Heart Transplantation: a Thirty-year Perspective

Annual Review of Medicine. 2002  |  Pubmed ID: 11818470

Heart transplantation has evolved over the past 30 years into a mainstay of therapy for heart failure patients. As the surgical technique and basic immunology were defined, heart transplantation became a real therapeutic option. Over the next few decades, thoracic transplant teams at Stanford University and other institutions refined this mode of therapy. This review addresses the history, current surgical technique, recipient and donor selection, postoperative care, immunosuppression, short- and long-term complications, and clinical outcomes associated with this procedure.

Up-regulation of Bcl-2 Through Hyperbaric Pressure Transfection of TGF-beta1 Ameliorates Ischemia-reperfusion Injury in Rat Cardiac Allografts

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Feb, 2002  |  Pubmed ID: 11834353

Oxidative stress after ischemia-reperfusion of cardiac allografts leads to activation of cardiomyocytes and production of cytokines. Bcl-2, an inhibitor of the apoptotic pathway, also has strong antioxidant properties. Ischemia-reperfusion injury after transplantation leads to decreased bcl-2 and increased tumor necrosis factor (TNF)-alpha levels. Transforming growth factor (TGF)-beta1 is known to attenuate ischemia-reperfusion injury and inhibits apoptosis of myofibroblasts. We hypothesize that TGF-beta1, prevents bcl-2 cleavage and increased TNF-alpha production.

Zinc Chloride-mediated Reduction of Apoptosis As an Adjunct Immunosuppressive Modality in Cardiac Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2002  |  Pubmed ID: 11897525

Zinc (Zn) blocks caspase-3 activation in cardiac allografts and therefore may synergistically decrease apoptosis along with cyclosporine (CsA), which inhibits mitochondrial release of cytochrome c. Simultaneous treatment of rat recipients of heterotopic heart transplants with zinc chloride (ZnCl(2)) thus may allow lower doses of CsA for immunosuppression.

Alternative Approach for Use of a Left Ventricular Assist Device with a Thrombosed Prosthetic Valve

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2002  |  Pubmed ID: 11897531

Implantation of a left ventricular assist device is problematic in patients with prosthetic heart valves, due to an increased risk of thrombosis with embolization. This report describes the use of a bovine pericardial patch to close the aortic outflow tract in a patient with a mechanical aortic valve and end-stage cardiomyopathy who required urgent left ventricular assist support. A successful outcome suggests that this technique may be of value in treating similar patients.

Ex Vivo Blockade of Endothelin-1 Inhibits Graft Coronary Artery Disease in a Rodent Cardiac Allograft Model

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Apr, 2002  |  Pubmed ID: 11927217

Graft coronary artery disease (GCAD) is characterized by vascular narrowing resulting from intimal hyperplasia. Endothelin (ET)-1, derived from the vascular endothelium and macrophages, stimulates vascular smooth muscle cells (SMCs), which leads to neointimal formation in donor graft coronary arteries. In this study, we hypothesized that antisense (AS) oligodeoxynucleotides (ODN) for preproendothelin-1 (ppET-1) delivered to rat cardiac allografts by means of hyperbaric pressure would reduce the incidence of GCAD.

VEGF Gene Delivery for Treatment of Ischemic Cardiovascular Disease

Trends in Cardiovascular Medicine. Apr, 2002  |  Pubmed ID: 12007735

There are increasing numbers of patients with ischemic myocardial disease not amenable to traditional methods of revascularization. These patients may benefit from new research into the use of naturally occurring angiogenic compounds, such as vascular endothelial growth factor (VEGF) for re-establishing blood flow into regions of hibernating myocardium. Animal studies and human clinical trials evaluating VEGF demonstrate increases in myocardial perfusion after treatment, with some patients reporting improvement in anginal symptoms. Further research into the ideal form of VEGF therapy (protein, plasmid, or adenoviral) and delivery method (intracoronary, intramyocardial, or epicardial) seems justified.

Lung and Heart-lung Transplantation in Patients with End-stage Cystic Fibrosis: the Stanford Experience

The Annals of Thoracic Surgery. Jul, 2002  |  Pubmed ID: 12118744

Bilateral lung (BLTx) and heart-lung transplantation have gained wide acceptance as treatment of end-stage lung disease from cystic fibrosis. We reviewed our 13-year experience with thoracic transplantation for cystic fibrosis with an operative approach that favors use of cardiopulmonary bypass for BLTx.

Consensus Conference Report: Maximizing Use of Organs Recovered from the Cadaver Donor: Cardiac Recommendations, March 28-29, 2001, Crystal City, Va

Circulation. Aug, 2002  |  Pubmed ID: 12176957

The shortage of available donor hearts continues to limit cardiac transplantation. For this reason, strict criteria have limited the number of patients placed on the US waiting list to approximately 6000 to 8000 per year. Because the number of available donor hearts has not increased beyond approximately 2500 per year, the transplant waiting list mortality rate remains substantial. Suboptimal and variable utilization of donor hearts has compounded the problem in the United States. In 1999, the average donor yield from 55 US regions was 39%, ranging from 19% to 62%. This report provides the detailed cardiac recommendations from the conference on "Maximizing Use of Organs Recovered From the Cadaver Donor" held March 28 to 29, 2001, in Crystal City, Va. The specific objective of the report is to provide recommendations to improve the evaluation and successful utilization of potential cardiac donors. The report describes the accuracy of current techniques such as echocardiography in the assessment of donor heart function before recovery and the impact of these data on donor yield. The rationale for and specific details of a donor-management pathway that uses pulmonary artery catheterization and hormonal resuscitation are provided. Administrative recommendations such as enhanced communication strategies among transplant centers and organ-procurement organizations, financial incentives for organ recovery, and expansion of donor database fields for research are also described.

The Use of (99m)technetium-labeled MCP-1 to Assess Graft Coronary Artery Disease in Rat Cardiac Allografts

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Sep, 2002  |  Pubmed ID: 12231372

Monocyte chemoattractant protein-1 (MCP-1) is associated with the development of graft coronary artery disease (GCAD) following cardiac transplantation. This study assessed whether technetium 99m ((99m)Tc)-labeled MCP-1 binds its receptors in chronic cardiac transplants and thereby provides a potential modality to assess GCAD.

Does Profound Hypothermic Circulatory Arrest Improve Survival in Patients with Acute Type a Aortic Dissection?

Circulation. Sep, 2002  |  Pubmed ID: 12354737

No evidence exists that profound hypothermic circulatory arrest (PHCA) improves survival or reduces the likelihood of distal aortic reoperation in patients with acute type A aortic dissection.

Absent Secretion to Vasoactive Intestinal Peptide in Cystic Fibrosis Airway Glands

The Journal of Biological Chemistry. Dec, 2002  |  Pubmed ID: 12368280

We are testing the hypothesis that the malfunctioning of airway gland serous cells is a component of cystic fibrosis (CF) airway disease. CF is caused by mutations that disrupt CF transmembrane conductance regulator, an anion channel essential for proper fluid secretion in some epithelia. Submucosal glands supply most of the mucus in upper airways, and gland serous cells are the primary site of CF transmembrane conductance regulator expression in airways. We have discovered a major defect in CF glands by in situ optical monitoring of secretions from single human airway glands. CF glands did not secrete to agents that elevated [cAMP](i) (0 responses/450 glands, 8 subjects), whereas glands were responsive in all donor tracheas (605/827 glands, 15 subjects) and in bronchi from subjects who were transplanted because of other lung diseases (148/166 glands, n = 10). CF glands secreted to cholinergic stimulation, and serous cells were abundant in glands from all CF subjects. The complete absence of secretion to agents that elevate [cAMP](i) suggests that altered secretion of gland mucus could contribute to CF lung disease.

Is Medical Therapy Still the Optimal Treatment Strategy for Patients with Acute Type B Aortic Dissections?

The Journal of Thoracic and Cardiovascular Surgery. Nov, 2002  |  Pubmed ID: 12407372

The optimal treatment of patients with acute type B dissections continues to be debated.

Coronary Atherosclerosis in Cardiac Transplant Patients Treated with Total Lymphoid Irradiation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Feb, 2003  |  Pubmed ID: 12581759

Multiple episodes of rejection following cardiac transplantation have been associated with an increased incidence of coronary atherosclerosis. Total lymphoid irradiation (TLI) has been shown to be a successful treatment for persistent allograft rejection, but its effect on coronary arterial disease has yet to be evaluated.

Antisense Oligonucleotides: Design, Construction, and Applications to Cardiac Allograft Transfer

Methods in Molecular Biology (Clifton, N.J.). 2003  |  Pubmed ID: 12597003

Novel Index for Invasively Assessing the Coronary Microcirculation

Circulation. Jul, 2003  |  Pubmed ID: 12821539

A relatively simple, invasive method for quantitatively assessing the status of the coronary microcirculation independent of the epicardial artery is lacking.

Antegrade Versus Retrograde Perfusion of the Donor Lung: Impact on the Early Reperfusion Phase

Transplant International : Official Journal of the European Society for Organ Transplantation. Nov, 2003  |  Pubmed ID: 12856115

Transpulmonary thermodilution was used to evaluate the effect of flush route during harvest on hemodynamic and respiratory function of the pulmonary graft in the early post-transplant phase. Single lung transplantation was performed in two piglet groups after 24 h of cold storage. Donor organs for group A underwent antegrade perfusion, and those for group R retrograde perfusion. PaO(2), compliance (C), airway resistance (R), extravascular lung water index (EVLWI), pulmonary blood volume index (PBVI), intrathoracic blood volume index (ITBVI), capillary leak (CL), and cardiac function index (CFI) were assessed by transpulmonary thermodilution at baseline, 1, 3, and 6 h after reperfusion. EVLWI was significantly lower in group R. Compliance and PaO(2) were higher in the same group. The two groups did not differ significantly with regard to CFI, PBVI, ITBVI, and airway resistance. Retrograde perfusion of the donor lung had a positive impact on graft function during early reperfusion. Transpulmonary hemodynamic monitoring can be a powerful tool for intra- and postoperative management of transplant patients.

Elevated Cyclic Adenosine Monophosphate Ameliorates Ischemia-reperfusion Injury in Rat Cardiac Allografts

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jul, 2003  |  Pubmed ID: 12873549

Oxidative stress after ischemia and reperfusion leads to leukocyte activation, the production of injurious cytokines, and increased expression of inflammatory adhesion molecules. This initial event is one of the most important alloantigen-independent factors associated with graft coronary artery disease (GCAD). Cyclic adenosine monophosphate (cAMP) is an important second messenger that inhibits the expression of tumor necrosis factor alpha (TNF-alpha), vascular cell adhesion molecule 1 (VCAM-1), and endothelial leukocyte adhesion molecule 1 (ELAM-1) in vitro. Its levels decrease during organ preservation. We hypothesized that augmenting allograft cAMP levels with the water-soluble adenylate cyclase activator, NKH477, could decrease ischemia-reperfusion injury and inhibit the progression of GCAD.

Long-term Results of Heart Transplantation in Patients Older Than 60 Years

The Journal of Thoracic and Cardiovascular Surgery. Jul, 2003  |  Pubmed ID: 12878959

Advanced age has been traditionally considered a relative contraindication for heart transplantation. Older patients are now considered as potential candidates for heart transplantation. The objective of this study was to evaluate the long-term results of heart transplantation in patients older than 60 years.

Effects of Adenoviral Up-regulation of Bcl-2 on Oxidative Stress and Graft Coronary Artery Disease in Rat Heart Transplants

Transplantation. Jul, 2003  |  Pubmed ID: 12883197

Bcl-2 has been shown to have antioxidant properties. Early oxidative stress is an important antigen-independent factor that contributes to the development of graft coronary artery disease (GCAD). We hypothesized that adenoviral up-regulation of bcl-2 would decrease early oxidative stress and inhibit GCAD after heart transplantation.

Quantification of Mechanical Stabilization for the Performance of Off-pump Coronary Artery Surgery

The Heart Surgery Forum. 2003  |  Pubmed ID: 12928205

Our objective was to analyze the motion of a coronary artery in 3-dimensional (3-D) space and to quantify the stabilization afforded by a mechanical arm using 3-D digital sonomicrometry.

Bcl-2-mediated Inhibition of Apoptosis in Rat Cardiac Allografts Worsens Development of Graft Coronary Artery Disease

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Sep, 2003  |  Pubmed ID: 12957608

We hypothesized that adenovirally mediated Bcl-2 transfection of donor hearts would reduce the apoptosis that occurs during acute rejection while worsening the development of chronic graft coronary artery disease (GCAD).

Comparison of Developmental Endothelial Locus-1 Angiogenic Factor with Vascular Endothelial Growth Factor in a Porcine Model of Cardiac Ischemia

The Annals of Thoracic Surgery. Oct, 2003  |  Pubmed ID: 14530019

This study compared the angiogenic effects of developmental endothelial locus-1 (DEL-1), vascular endothelial growth factor (VEGF), as well as the negative control, beta-galactosidase (beta-gal), in a porcine model of cardiac ischemia.

Longer-term Risks Associated with 10-year Survival After Heart Transplantation in the Cyclosporine Era

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Oct, 2003  |  Pubmed ID: 14550819

Long-term survival after heart transplantation is common in the cyclosporine era. However, there are few data documenting pre-transplant/peri-operative factors predictive of truly long-term survival (>10 years). The purpose of this study is to identify factors associated with 10-year survival after heart transplantation.

Atrial Tachyarrhythmias and Permanent Pacing After Pediatric Heart Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Oct, 2003  |  Pubmed ID: 14550822

Atrial tachyarrhythmias have been reported in as high as 50% of adult heart recipients. Limited information is available on arrhythmias in pediatric transplant patients. Our objective was to determine the prevalence and significance of atrial tachyarrhythmias and permanent pacing following pediatric heart transplantation.

L-Arginine Polymers Enhance Coronary Flow and Reduce Oxidative Stress Following Cardiac Transplantation in Rats

The Journal of Thoracic and Cardiovascular Surgery. Oct, 2003  |  Pubmed ID: 14566248

Hearts treated with l-arginine polymers have demonstrated upregulated production of nitric oxide. The current study examined whether these polymers improved coronary flow and reduced myocardial oxidative stress after rat heart transplantation.

Comparison of Coronary Thermodilution and Doppler Velocity for Assessing Coronary Flow Reserve

Circulation. Nov, 2003  |  Pubmed ID: 14568891

Thermodilution coronary flow reserve (CFRthermo) is a new technique for invasively measuring coronary flow reserve (CFR) with a coronary pressure wire and is based on the ability of the pressure transducer to also measure temperature changes. Whether CFRthermo correlates well enough with absolute flow-derived CFR (CFRflow) to replace Doppler wire-derived CFR (CFRDoppler) remains unclear.

The Impact of Brain Death on Survival After Heart Transplantation: Time is of the Essence

Transplantation. Nov, 2003  |  Pubmed ID: 14627902

It has been suggested that the modality of brain death and time from brain death until harvest impact survival and rejection after heart transplantation.

Acute Type A Aortic Dissection Complicated by Aortic Regurgitation: Composite Valve Graft Versus Separate Valve Graft Versus Conservative Valve Repair

The Journal of Thoracic and Cardiovascular Surgery. Dec, 2003  |  Pubmed ID: 14688716

To clarify the merits of various surgical approaches, we studied the outcome after composite valve graft versus separate valve and graft replacement versus conservative valve treatment with replacement of the ascending aorta in patients with acute type A aortic dissection complicated by aortic regurgitation.

A Few Critical Aspects--and Achilles Heels--of Tissue Engineering Approaches to Restore Injured Myocardium

The Journal of Thoracic and Cardiovascular Surgery. Dec, 2003  |  Pubmed ID: 14688751

Analysis of Survivors More Than 10 Years After Heart Transplantation in the Cyclosporine Era: Stanford Experience

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Feb, 2004  |  Pubmed ID: 14761762

Truly long term survival post heart transplantation has become increasingly frequent over the past two decades.

Identifying Cardiac Transplant Rejection in Children: Diagnostic Utility of Echocardiography, Right Heart Catheterization and Endomyocardial Biopsy Data

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2004  |  Pubmed ID: 15019642

There has been a continued search for alternative diagnostic techniques that do not necessitate endomyocardial biopsy for diagnosing rejection in cardiac transplant recipients. The purpose of this study is to evaluate the role of echocardiography and hemodynamic catheterization data compared with endomyocardial biopsy results, in rejection surveillance for the pediatric heart transplant recipient.

Gastric Pacing for Severe Gastroparesis in a Heart-lung Transplant Recipient

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2004  |  Pubmed ID: 15019648

Gastroparesis is a serious complication of lung and heart-lung transplantation that can lead to malnutrition, gastroesophageal reflux, aspiration pneumonia and deteriorating lung function. Some patients with severe gastroparesis have symptoms that are refractory to dietary modifications and gastric promotility agents and require surgery. We describe the successful use of gastric pacing for the management of intractable gastroparesis, malnutrition and recurrent aspiration in a heart-lung allograft recipient. Lung transplant recipients with severe gastroparesis may benefit from gastric pacing.

Haematopoietic Stem Cells Adopt Mature Haematopoietic Fates in Ischaemic Myocardium

Nature. Apr, 2004  |  Pubmed ID: 15034594

Under conditions of tissue injury, myocardial replication and regeneration have been reported. A growing number of investigators have implicated adult bone marrow (BM) in this process, suggesting that marrow serves as a reservoir for cardiac precursor cells. It remains unclear which BM cell(s) can contribute to myocardium, and whether they do so by transdifferentiation or cell fusion. Here, we studied the ability of c-kit-enriched BM cells, Lin- c-kit+ BM cells and c-kit+ Thy1.1(lo) Lin- Sca-1+ long-term reconstituting haematopoietic stem cells to regenerate myocardium in an infarct model. Cells were isolated from transgenic mice expressing green fluorescent protein (GFP) and injected directly into ischaemic myocardium of wild-type mice. Abundant GFP+ cells were detected in the myocardium after 10 days, but by 30 days, few cells were detectable. These GFP+ cells did not express cardiac tissue-specific markers, but rather, most of them expressed the haematopoietic marker CD45 and myeloid marker Gr-1. We also studied the role of circulating cells in the repair of ischaemic myocardium using GFP+-GFP- parabiotic mice. Again, we found no evidence of myocardial regeneration from blood-borne partner-derived cells. Our data suggest that even in the microenvironment of the injured heart, c-kit-enriched BM cells, Lin- c-kit+ BM cells and c-kit+ Thy1.1(lo) Lin- Sca-1+ long-term reconstituting haematopoietic stem cells adopt only traditional haematopoietic fates.

Distinct Cell-to-fiber Junctions Are Critical for the Establishment of Cardiotypical Phenotype in a 3D Bioartificial Environment

Medical Engineering & Physics. Mar, 2004  |  Pubmed ID: 15036183

The first step toward improving the cell-matrix interactions that occur in bioartificial myocardial tissue is an understanding of the ultrastructural links between cells and host fibers. Here, we identify a distinct type of junction that helps the cells to find anchorage in the three-dimensional environment, and we evaluate the phenotype of the resulting tissue. Neonatal rat cardiomyocytes were seeded in two different collagen scaffolds after pre-hydration of the scaffold. Conventional and electron microscopy were used to analyze the tissue microstructure. Viability was assessed by life/dead assay and physical properties of the resulting tissue were evaluated. The resulting tissue displayed high cellular viability, spontaneous contractions over 12 weeks, and responded to passive stretch similar to native rat myocardium. Contractile force responded physiologically to calcium (Ca), adrenaline, and stretch administration. Ultrastructural studies revealed a cell-to-fiber junction, as well as a background matrix configuration, which has not been described before in this context. The cells aligned along collagen fibers and engaged in complex intercalations. The cell-to-fiber affinity is essential for the phenotypical performance of bioartificial myocardial tissue equivalents. Moreover, given the appropriate porosity of the scaffold, pre-hydration promotes migration and affinity of cells to host structures.

Will Minimally Invasive Valve Replacement Ever Really Be Important?

Current Opinion in Cardiology. Mar, 2004  |  Pubmed ID: 15075738

Most cardiac surgical centers worldwide have instituted some form of minimally invasive surgery into their operative armamentarium. However, skepticism still remains whether minimally invasive valve replacement will ever really be important. This review first addresses the definition of minimally invasive surgery and then analyzes the possible advantages and disadvantages of minimally invasive valvular surgery.

Chylothorax After Heart/lung Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. May, 2004  |  Pubmed ID: 15135382

Chylothorax is a potentially serious complication of lung and heart-lung transplantation. This article describes the clinical course of chylothorax in 3 heart-lung allograft recipients. We discuss management options, including dietary modifications, octreotide infusion, thoracic duct ligation and embolization, and surgical pleurodesis. In addition, we describe the novel use of aminocaproic acid to reduce lymph flow. We propose a multidisciplinary approach for the management of chylothorax that includes both medical and surgical options.

Microvascular Resistance is Not Influenced by Epicardial Coronary Artery Stenosis Severity: Experimental Validation

Circulation. May, 2004  |  Pubmed ID: 15136503

The effect of epicardial artery stenosis on myocardial microvascular resistance remains controversial. Recruitable collateral flow, which may affect resistance, was not incorporated into previous measurements.

Effects of AGI-1096, a Novel Antioxidant Compound with Anti-inflammatory and Antiproliferative Properties, on Rodent Allograft Arteriosclerosis

Transplantation. May, 2004  |  Pubmed ID: 15239610

AGI-1096 is a novel phenolic intracellular antioxidant with anti-inflammatory and antiproliferative properties. In vitro, AGI-1096 inhibited the inducible expression of vascular cell adhesion molecule (VCAM)-1, E-selectin, and monocyte chemoattractant protein (MCP)-1 in endothelial cells and tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta secretion from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells. It also inhibited serum-stimulated proliferation of aortic smooth-muscle cells. In vivo, AGI-1096 demonstrated anti-inflammatory properties in a murine delayed-type hypersensitivity model. Given these antioxidant, anti-inflammatory and antiproliferative properties, we reasoned that AGI-1096 may be able to prevent chronic allograft arteriosclerosis. This hypothesis was tested in a rodent aortic transplantation model.

Cardiomyocyte-specific Bcl-2 Overexpression Attenuates Ischemia-reperfusion Injury, Immune Response During Acute Rejection, and Graft Coronary Artery Disease

Blood. Dec, 2004  |  Pubmed ID: 15280201

After cardiac transplantation, graft damage occurs secondary to ischemia-reperfusion injury and acute rejection. This damage ultimately leads to the development of graft coronary artery disease (GCAD), which limits long-term graft survival. Apoptosis is directly involved in graft injury, contributing to the development of GCAD. To assess the role of the antiapoptotic factor Bcl-2 in the process of GCAD, we transplanted hearts from FVB transgenic mice overexpressing human Bcl-2 under the control of alpha-myosin heavy chain promoter into allogenic C57BL/6 mice. Bcl-2 overexpression led to reduced cytochrome c-mediated caspase-9-dependent cardiomyocyte apoptosis and local inflammation (neutrophil infiltration and proinflammatory cytokine production) in cardiac allografts during ischemia-reperfusion injury and also led to reduced immune responses (inflammatory cell infiltration, production of T(H)1 cytokines and chemokines, and expression of adhesion molecules) during acute and chronic rejection without affecting host CD4(+) and CD8(+) cell responses in the spleen. Thus, local Bcl-2 expression directly contributes to the modulation of local immune responses in allograft rejection, resulting in attenuated GCAD. In conclusion, our findings suggest that the modulation of Bcl-2 expression by pharmacologic up-regulation or gene transfer may be of clinical benefit in the short- and long-term function of cardiac allografts.

Suppression of Graft Coronary Artery Disease by a Brief Treatment with a Selective EpsilonPKC Activator and a DeltaPKC Inhibitor in Murine Cardiac Allografts

Circulation. Sep, 2004  |  Pubmed ID: 15364862

Inhibiting delta protein kinase C (deltaPKC) during reperfusion and activating epsilon PKC (epsilonPKC) before ischemia each limits cardiac ischemic injury. Here, we examined whether limiting ischemia-reperfusion injury inhibits graft coronary artery disease (GCAD) and improves murine cardiac allografting.

Overexpression of Human Copper/zinc Superoxide Dismutase (SOD1) Suppresses Ischemia-reperfusion Injury and Subsequent Development of Graft Coronary Artery Disease in Murine Cardiac Grafts

Circulation. Sep, 2004  |  Pubmed ID: 15364863

Ischemia-reperfusion injury is an important risk factor for graft coronary artery disease (GCAD). We hypothesized that overexpression of SOD1 in donor hearts would suppress ischemia-reperfusion injury and thereby reduce GCAD.

Injectable Bioartificial Myocardial Tissue for Large-scale Intramural Cell Transfer and Functional Recovery of Injured Heart Muscle

The Journal of Thoracic and Cardiovascular Surgery. Oct, 2004  |  Pubmed ID: 15457158

Most tissue-engineering approaches to restore injured heart muscle result in distortion of left ventricular geometry. In the present study we suggest seeding embryonic stem cells in a liquid matrix for myocardial restoration.

The Road to Clinical Xenotransplantation: a Worthwhile Journey

Transplantation. Oct, 2004  |  Pubmed ID: 15502703

Xenotransplantation carries numerous ethical dilemmas. In the Position Paper of the Ethics Committee of the International Xenotransplantation Association, Sykes et al. diagram important ethics issues including respect for clinical subjects characterized by proper informed consent, and beneficence to the patient and the community at large, highlighting the possible risk of porcine endogenous retroviruses and xenotourism. We propose optimizing informed consent to take into account the psychological, scientific, and ethical nuances of xenotransplantation. Moreover, regulation of xenotourism should mirror established U.S. guidelines for visitors with communicable diseases, thereby not limiting the rights of xenotransplant recipients.

Superoxide Dismutase Mimetic M40401 Reduces Ischemia-reperfusion Injury and Graft Coronary Artery Disease in Rodent Cardiac Allografts

Transplantation. Oct, 2004  |  Pubmed ID: 15502714

The oxidative stress associated with ischemia-reperfusion (I/R) of cardiac allografts leads to production of injurious cytokines and expression of proinflammatory adhesion molecules. This is one of the most important alloantigen-independent factors associated with graft coronary artery disease (GCAD). M40401 is a newly developed cell permeable superoxide dismutase mimetic, which has been shown to scavenge superoxide anion with highly specific and enhanced catalytic activity. We hypothesized that M40401 would exert a protective effect in I/R injury of cardiac allografts and ameliorate the progression of GCAD.

Insulin-like Growth Factor Promotes Engraftment, Differentiation, and Functional Improvement After Transfer of Embryonic Stem Cells for Myocardial Restoration

Stem Cells (Dayton, Ohio). 2004  |  Pubmed ID: 15579642

Insulin-like growth factor-1 (IGF-1) promotes myocyte proliferation and can reverse cardiac abnormalities when it is administered in the early fetal stage. Supplementation of a mouse embryonic stem cell (ESC) suspension with IGF-1 might enhance cellular engraftment and host organ-specific differentiation after injection in the area of acute myocardial injury. In the study reported here, we sought to enhance the restorative effect of ESCs in the injured heart by adding IGF-1 to the injected cell population. Green fluorescent protein (GFP)-labeled sv129 ESCs (2.5 x 10(5)) were injected into the ischemic area after left anterior descending (LAD) artery ligation in BalbC mice. Recombinant mouse IGF-1 (25 ng) was added to the cell suspension prior to the injection (n = 5). Echocardiography was performed before organ harvest 2 weeks later. The degree of restoration (ratio of GFP+ to infarct area), expression of cardiac markers by GFP+ cells, inflammatory response, and tumorigenicity were evaluated. Mice with LAD ligation only (n = 5) and ESC transfer without IGF-1 (n = 5) served as controls. ESCs formed viable grafts and improved cardiac function. Left ventricular wall thickness was higher in the IGF-1 group (p = .025). There was a trend toward higher fractional shortening in the IGF-treated group. Histological analysis demonstrated that IGF-1 promoted expression of alpha-sarcomeric actin (p = .015) and major histocompatibility complex class I (p = .01). IGF did not affect the cellular response to the donor cells or tumorigenicity. IGF-1 promotes expression of cardiomyocyte phenotype in ESCs in vivo. It should be considered as an adjuvant to cell transfer for myocardial restoration.

Matrix Metalloproteinase Inhibition Decreases Ischemia-reperfusion Injury After Lung Transplantation

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. Jan, 2004  |  Pubmed ID: 14678033

Increased microvascular permeability and extravasation of inflammatory cells are key events of lung ischemia-reperfusion (IR) injury. The purpose of this study was to investigate the role of matrix metalloproteinases (MMP) in IR-induced alveolar capillary membrane disruption after experimental lung transplantation. We used a rat model of lung orthotopic transplantation (n = 86) with a prolonged cold ischemic phase. MMP2 and MMP9 were elevated 4 h after the onset of ischemia and further increased during reperfusion. Compared to sham values, the alveolar-capillary membrane permeability increased by 105% and 82.6% after 4 h of ischemia and 2 h or 24 h of reperfusion, respectively. A 4- and 5-fold increase of the infiltration of ischemic tissue by neutrophils was also observed after 2 h and 24 h of reperfusion. The PO2/FIO2 ratio dropped significantly from 244 to 76.6 after 2 h of reperfusion and from 296.4 to 127.6 after 24 h of reperfusion. A nonselective inhibitor of MMP, administered to the rats and added to the preservation solution, reduced significantly the alveolar-capillary leakage, the transmigration of neutrophils and improved gas exchanges in animals submitted to 4 h of ischemia combined with 2 h or 24 h of reperfusion. We conclude that inhibition of MMP attenuates IR injury after experimental lung transplantation.

Pre-transplant Blood Transfusion and Cyclosporin A Induce Long-term Hamster Cardiac Xenograft Survival in Immunocompetent Rats

Xenotransplantation. Jan, 2005  |  Pubmed ID: 15598275

In previous studies we have shown that pre-transplant hamster blood transfusion (HBT) can induce non-responsiveness in the T cell independent immunecompartment and result in tolerance towards hamster cardiac xenografts (Xgs) in T cell deficient athymic nude rats. In this study we test the combination of pre-transplant HBT with cyclosporin A (CSA) in immunocompetent Lewis rats.

Successful Repair of Tracheal Dehiscence After Heart-lung Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jan, 2005  |  Pubmed ID: 15653388

Tracheal dehiscence remains one of the most feared complications after heart-lung transplantation because of its nearly universal fatality rate. Drawing on experiences from the tracheal reconstruction and the lung transplantation literature, we report the successful repair of tracheal dehiscence, after heart-lung transplantation, with an intercostal muscle flap.

Lung Transplantation: a Decade of Experience

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Feb, 2005  |  Pubmed ID: 15701428

Over the past 3 decades, the field of lung transplantation has been refined. However, many barriers exist that limit long-term success. The purpose of this study was to review a single institution's long-term experience with single and double lung transplantation and to assess the effect of different immunosuppressive therapies on outcomes.

Graft Coronary Artery Disease in Murine Cardiac Allografts: Proposal to Meet the Need for Standardized Assessment

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2005  |  Pubmed ID: 15737759

Inconsistency exists in assessing the severity of graft coronary artery disease (GCAD) in studies that use mouse models. The central issue associated with this inconsistency is the lack of a standardized approach for assessing mouse GCAD.

Cyclosporine Treatment of High Dose and Long Duration Reduces the Severity of Graft Coronary Artery Disease in Rodent Cardiac Allografts

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Apr, 2005  |  Pubmed ID: 15797746

Graft coronary artery disease (GCAD) limits allograft survival after cardiac transplantation. The objective of this study was to correlate GCAD with the level of immunosuppression in an established allogeneic rodent cardiac chronic rejection model to better understand the mechanisms of GCAD in this system.

Cyclosporine Mitigates Graft Coronary Artery Disease in Murine Cardiac Allografts: Description and Validation of a Novel Fully Allogeneic Model

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Apr, 2005  |  Pubmed ID: 15797747

The effect of cyclosporine (CsA) on the development of graft coronary artery disease (GCAD) is controversial. We developed a novel allogeneic mouse model of heart transplantation and investigated the effect of CsA on acute rejection and GCAD.

Overexpression of Human Bcl-2 in Syngeneic Rat Donor Lungs Preserves Posttransplant Function and Reduces Intragraft Caspase Activity and Interleukin-1beta Production

Transplantation. Apr, 2005  |  Pubmed ID: 15818317

A significant cause of primary graft failure in lung transplantation is ischemia-reperfusion (I/R). I/R injury generates proinflammatory cytokines, such as interleukin (IL)-1beta, and activates the caspase-mediated pathways of alveolar epithelial apoptosis. The authors investigated whether gene transfer of the human antiapoptotic protein Bcl-2 by means of intratracheal adenoviral administration would preserve posttransplant lung function and reduce intragraft activated caspase activity and IL-1beta production in syngeneic rat donor lung grafts.

Caspase-3 Inhibition Preserves Myocardial Geometry and Long-term Function After Infarction

The Journal of Surgical Research. Apr, 2005  |  Pubmed ID: 15820248

Cardiac remodeling after infarction is characterized by progressive ventricular dilation and functional impairment. Although surgical and percutaneous revascularization strategies may prevent remodeling, not all patients are candidates for these procedures. Apoptosis in the border-zone myocardium is thought to be critical to the remodeling process, and caspase-3 is a downstream effector of apoptosis. We hypothesized that inhibition of caspase-3 activity might limit dysfunction and remodeling after permanent coronary artery ligation.

Inhibition of Heart Transplant Injury and Graft Coronary Artery Disease After Prolonged Organ Ischemia by Selective Protein Kinase C Regulators

The Journal of Thoracic and Cardiovascular Surgery. May, 2005  |  Pubmed ID: 15867794

Transplanted hearts subjected to prolonged ischemia develop ischemia-reperfusion injury and graft coronary artery disease. To determine the effect of delta-protein kinase C and -protein kinase C on ischemia-reperfusion injury and the resulting graft coronary artery disease induced by prolonged ischemia, we used a delta-protein kinase C-selective inhibitor peptide and an -protein kinase C-selective activator peptide after 30 or 120 minutes of ischemia.

Stimulation of Paracrine Pathways with Growth Factors Enhances Embryonic Stem Cell Engraftment and Host-specific Differentiation in the Heart After Ischemic Myocardial Injury

Circulation. May, 2005  |  Pubmed ID: 15883216

Growth factors play an essential role in organogenesis. We examine the potential of growth factors to enhance cell engraftment and differentiation and to promote functional improvement after transfer of undifferentiated embryonic stem cells into the injured heart.

Progression of Alloresponse and Tissue-specific Immunity During Graft Coronary Artery Disease

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. Jun, 2005  |  Pubmed ID: 15888032

Chronic rejection remains the major obstacle for long-term transplant survival. Both indirect alloresponse and tissue-specific autoimmunity have been implicated in its pathogenesis. The interrelationship between these two types of host anti-graft response remains poorly understood. We have developed an immunosuppression-free mouse model of graft coronary artery disease (GCAD), in which all FVB (H-2(q)) cardiac allografts placed into minor Ag (mHC)-mismatched DBA/1 (H-2(q)) hosts survived more than 112 days, and developed GCAD. We then examined the kinetics of both anti-mHC alloresponse and host autoimmunity against heart-specific antigen, cardiac myosin (CM). At 8 days post-transplantation, recipient mice showed minimal intragraft inflammation and apoptosis, and limited expansion of allo-specific T cells. In addition, we observed early production of anti-myosin IgG1 autoantibodies, which occurred in the absence of activated CM-specific T lymphocytes. By day 56, GCAD indices, the numbers of mHC- and CM-reactive T cells, and the levels of circulating allo- and CM-specific antibodies were all significantly increased. While host alloresponse was exhausted at 112 days post-transplant, T-cell reactivity against CM persisted. Our data suggest that both allo- and tissue-specific immunity might contribute to the induction of GCAD. They indicate that continual autoimmune response against graft tissue antigens may provide for GCAD sustenance.

Comparing On-pump and Off-pump Coronary Artery Bypass Grafting: Numerous Studies but Few Conclusions: a Scientific Statement from the American Heart Association Council on Cardiovascular Surgery and Anesthesia in Collaboration with the Interdisciplinary Working Group on Quality of Care and Outcomes Research

Circulation. May, 2005  |  Pubmed ID: 15927994

One of the most hotly debated and polarizing issues in cardiac surgery has been whether coronary artery bypass grafting (CABG) without the use of cardiopulmonary bypass or cardioplegia (off-pump CABG, or OPCAB) is superior to that performed with the heart-lung machine and the heart's being chemically arrested (standard CABG). Various clinical trials are reviewed comparing the 2 surgical strategies, including several large retrospective analyses, meta-analyses, and the randomized trials that address different aspects of standard CABG and OPCAB. Although definitive conclusions about the relative merits of standard CABG and OPCAB are difficult to reach from these varied randomized and nonrandomized studies, several generalizations may be possible. Patients may achieve an excellent outcome with either type of procedure, and individuals' outcomes likely depend more on factors other than whether they underwent standard CABG or OPCAB. Nevertheless, there appear to be trends in most studies. These trends include less blood loss and need for transfusion after OPCAB, less myocardial enzyme release after OPCAB up to 24 hours, less early neurocognitive dysfunction after OPCAB, and less renal insufficiency after OPCAB. Fewer grafts tend to be performed with OPCAB than with standard CABG. Length of hospital stay, mortality rate, and long-term neurological function and cardiac outcome appear to be similar in the 2 groups. To definitively answer the remaining questions of whether either strategy is superior and in which patients, a large-scale prospective randomized trial is required.

Myocardial Restoration with Embryonic Stem Cell Bioartificial Tissue Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jun, 2005  |  Pubmed ID: 15949735

The optimal cell-matrix combination for robust and sustained myocardial restoration has not been identified. The present study utilizes embryonic stem cells as the substrate of bioartificial myocardial tissue and evaluates engraftment in, and functional recovery of, the recipient heart.

Early Inhibition of Caspase-3 Activity Lessens the Development of Graft Coronary Artery Disease

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jul, 2005  |  Pubmed ID: 15982609

The role of apoptosis in the development of graft coronary artery disease (GCAD) is poorly understood. We have previously shown that early overexpression of the anti-apoptotic protein Bcl-2 lessens the development of GCAD. We hypothesized that early inhibition of apoptosis with a caspase-3 inhibitor would also lessen the development of GCAD.

Molecular Imaging Using Labeled Donor Tissues Reveals Patterns of Engraftment, Rejection, and Survival in Transplantation

Transplantation. Jul, 2005  |  Pubmed ID: 16003245

Tissue regeneration and transplantation of solid organs involve complex processes that can only be studied in the context of the living organism, and methods of analyzing these processes in vivo are essential for development of effective transplantation and regeneration procedures. We utilized in vivo bioluminescence imaging (BLI) to noninvasively visualize engraftment, survival, and rejection of transplanted tissues from a transgenic donor mouse that constitutively expresses luciferase. Dynamic early events of hematopoietic reconstitution were accessible and engraftment from as few as 200 transplanted whole bone marrow (BM) cells resulted in bioluminescent foci in lethally irradiated, syngeneic recipients. The transplantation of autologous pancreatic Langerhans islets and of allogeneic heart revealed the tempo of transplant degeneration or immune rejection over time. This imaging approach is sensitive and reproducible, permits study of the dynamic range of the entire process of transplantation, and will greatly enhance studies across various disciplines involving transplantation.

Dimethylarginine Dimethylaminohydrolase Overexpression Suppresses Graft Coronary Artery Disease

Circulation. Sep, 2005  |  Pubmed ID: 16144995

Graft coronary artery disease (GCAD) is the leading cause of death after the first year of heart transplantation. The reduced bioavailability of endothelium-derived nitric oxide (NO) may play a role in endothelial vasodilator dysfunction and the structural changes that are characteristic of GCAD. A potential contributor to endothelial pathobiology is asymmetric dimethylarginine (ADMA), an endogenous NO synthase inhibitor. We hypothesized that lowering ADMA concentrations by dimethylarginine dimethylaminohydrolase (DDAH) overexpression in the recipient might suppress GCAD and long-term immune responses in murine cardiac allografts.

In Vivo Visualization of Cardiac Allograft Rejection and Trafficking Passenger Leukocytes Using Bioluminescence Imaging

Circulation. Aug, 2005  |  Pubmed ID: 16159800

We investigated the feasibility of bioluminescence imaging (BLI) for the in vivo assessment of cardiac allograft viability and visualization of passenger leukocytes during the course of acute rejection.

Embryonic Stem Cell Immunogenicity Increases Upon Differentiation After Transplantation into Ischemic Myocardium

Circulation. Aug, 2005  |  Pubmed ID: 16159810

We investigated whether differentiation of embryonic stem cells (ESCs) in ischemic myocardium enhances their immunogenicity, thereby increasing their chance for rejection.

Novel Injectable Bioartificial Tissue Facilitates Targeted, Less Invasive, Large-scale Tissue Restoration on the Beating Heart After Myocardial Injury

Circulation. Aug, 2005  |  Pubmed ID: 16159811

Implantation of bioartificial patches distorts myocardial geometry, and functional improvement of the recipient heart is usually attributed to reactive angiogenesis around the graft. With the liquid bioartificial tissue compound used in this study, we achieved targeted large-scale support of the infarcted left ventricular wall and improvement of heart function.

Haematopoietic Stem Cells and Repair of the Ischaemic Heart

Clinical Science (London, England : 1979). Dec, 2005  |  Pubmed ID: 16287425

HSCs (haematopoietic stem cells) are multipotent stem cells that give rise to all cells of the blood cell lineage. In recent years, it has been proposed that bone marrow serves as a reservoir for cardiomyogenic precursors and that, following cardiac injury, these stem cells circulate to the site of injury where they contribute to myocardial repair and regeneration. This concept of stem cell plasticity has been controversial and, in fact, several key studies on the cardiomyogenic potential of HSCs have not been reproducible in the hands of independent investigators. Despite this controversy, the clinical community has pushed forward with clinical trials of bone marrow transplantation for the treatment of ischaemic heart disease. The following review summarizes the mechanistic underpinnings of bone marrow transplantation into ischaemic myocardium, focusing on the basic science that forms the foundation of this field, and highlights the controversies and new avenues for research that have emerged. It also describes the current state of the art in clinical trials of bone marrow transplantation for heart failure.

Prolonged Cold Ischemia in Rat Cardiac Allografts Promotes Ischemia-reperfusion Injury and the Development of Graft Coronary Artery Disease in a Linear Fashion

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Nov, 2005  |  Pubmed ID: 16297799

Prolonged cold ischemia is thought to exacerbate ischemia-reperfusion injury and graft coronary artery disease (GCAD). We investigated the effect of varying lengths of cold ischemia on inflammation and apoptosis during ischemia-reperfusion injury and correlated this with the degree of GCAD in rat cardiac allografts.

Executive Summary for the National Heart, Lung, and Blood Institute Working Group on Next Generation Ventricular Assist Devices for Destination Therapy

Seminars in Thoracic and Cardiovascular Surgery. 2005  |  Pubmed ID: 16428046

Thoratec Ventricular Assist Devices in Pediatric Patients: Update on Clinical Results

ASAIO Journal (American Society for Artificial Internal Organs : 1992). Sep-Oct, 2005  |  Pubmed ID: 16322705

Particularly in pediatric patients, mechanical circulatory support remains a clinical challenge. We analyzed the Stanford experience with use of the Thoratec ventricular assist device (VAD) in children and adolescents and data from the company's voluntary database. Through January 2005, 209 patients up to 18 years of age have been supported with the Thoratec VAD worldwide. Mean age was 14.5 years (range 5-18 years), mean weight was 57 kg (range 17-118 kg), and mean body surface area was 1.6 m2 (range 0.7-2.3 m2). The majority of patients were supported for cardiomyopathies (55%) and acute myocarditis (25%). A minority (6%) was treated for end-stage congenital heart disease. Average duration of support was 44 days (0-434 days). Overall survival to transplantation or weaning off the device was 68%. Survival rates were higher for patients with cardiomyopathies (74%) and acute myocarditis (86%) compared with patients with congenital heart disease (27%). We performed a subanalysis in small children with a body surface area of less 1.3 m2. This subgroup had a higher incidence of congenital heart disease and a slightly lower survival (52%). Aspects of the particular risks and device management in these small patients are discussed.

Allopurinol/uricase and Ibuprofen Enhance Engraftment of Cardiomyocyte-enriched Human Embryonic Stem Cells and Improve Cardiac Function Following Myocardial Injury

European Journal of Cardio-thoracic Surgery : Official Journal of the European Association for Cardio-thoracic Surgery. Jan, 2006  |  Pubmed ID: 16337396

A major limitation of stem cell transfer is early donor-cell death. Here, we seek to enhance myocardial repair following injury through transplantation of cardiomyocyte-enriched human embryonic stem cells (hESC) and recipient treatment with cytoprotective (allopurinol+uricase) and anti-inflammatory (ibuprofen) agents.

Are Heart-lung Transplant Recipients Protected from Developing Bronchiolitis Obliterans Syndrome?

The Annals of Thoracic Surgery. Jan, 2006  |  Pubmed ID: 16368382

Heart-lung transplant recipients, when compared with heart transplant recipients, are relatively spared from allograft coronary artery disease. This study was undertaken to investigate whether heart-lung transplant recipients are also spared from experiencing bronchiolitis obliterans syndrome (BOS) when compared with double-lung transplant recipients. In addition, the risk factors for developing BOS after lung transplantation were analyzed.

Transcriptional Profiling of Reporter Genes Used for Molecular Imaging of Embryonic Stem Cell Transplantation

Physiological Genomics. Mar, 2006  |  Pubmed ID: 16390873

Stem cell therapy offers exciting promise for treatment of ischemic heart disease. Recent advances in molecular imaging techniques now allow investigators to monitor cell fate noninvasively and repetitively. Here we examine the effects of a triple-fusion reporter gene on embryonic stem (ES) cell transcriptional profiles. Murine ES cells were stably transfected with a self-inactivating lentiviral vector carrying a triple-fusion (TF) construct consisting of fluorescence, bioluminescence, and positron emission tomography (PET) reporter genes. Fluorescence-activated cell sorting (FACS) analysis allowed isolation of stably transfected populations. Microarray studies comparing gene expression in nontransduced control ES cells vs. stably transduced ES cells expressing triple fusion (ES-TF) revealed some increases in transcriptional variability. Annotation analysis showed that ES-TF cells downregulated cell cycling, cell death, and protein and nucleic acid metabolism genes while upregulating homeostatic and anti-apoptosis genes. Despite these transcriptional changes, expression of the TF reporter gene had no significant effects on ES cell viability, proliferation, and differentiation capability. Importantly, transplantation studies in murine myocardium demonstrated the feasibility of tracking ES-TF cells in living subjects using bioluminescence and PET imaging. Taken together, this is the first study to analyze in detail the effects of reporter genes on molecular imaging of ES cells.

New Directions in Cardiac Transplantation

Annual Review of Medicine. 2006  |  Pubmed ID: 16409160

More than three decades of clinical experience in cardiac transplantation resulted in the spread of the procedure worldwide with a wealth of knowledge and advancements. Developments included liberalization of recipient and donor selection criteria, improved surgical techniques, novel immunosuppressive drugs and protocols, new rejection surveillance techniques, and better understanding of the pathophysiology of cardiac allograft vasculopathy to direct interventions for prevention and treatment.

Hyposecretion, Not Hyperabsorption, is the Basic Defect of Cystic Fibrosis Airway Glands

The Journal of Biological Chemistry. Mar, 2006  |  Pubmed ID: 16410244

Human airways and glands express the anion channel cystic fibrosis transmembrane conductance regulator, CFTR, and the epithelial Na(+) channel, ENaC. Cystic fibrosis (CF) airway glands fail to secrete mucus in response to vasoactive intestinal peptide or forskolin; the failure was attributed to loss of CFTR-mediated anion and fluid secretion. Alternatively, CF glands might secrete acinar fluid via CFTR-independent pathways, but the exit of mucus from the glands could be blocked by hyperabsorption of fluid in the gland ducts. This could occur because CFTR loss can disinhibit ENaC, and ENaC activity can drive absorption. To test these two hypotheses, we measured single gland mucus secretion optically and applied ENaC inhibitors to determine whether they augmented secretion. Human CF glands were pretreated with benzamil and then stimulated with forskolin in the continued presence of benzamil. Benzamil did not rescue the lack of secretion to forskolin (50 glands, 6 CF subjects) nor did it increase the rate of cholinergically mediated mucus secretion from CF glands. Finally, neither benzamil nor amiloride increased forskolin-stimulated mucus secretion from porcine submucosal glands (75 glands, 7 pigs). One possible explanation for these results is that ENaC within the gland ducts was not active in our experiments. Consistent with that possibility, we discovered that human airway glands express Kunitz-type and non-Kunitz serine protease inhibitors, which might prevent proteolytic activation of ENaC. Our results suggest that CF glands do not display excessive, ENaC-mediated fluid absorption, leaving defective, anion-mediated fluid secretion as the most likely mechanism for defective mucus secretion from CF glands.

Successful Repair of Blunt Injury of Aortic Arch Branches in the Setting of Bovine Arch

Journal of Vascular Surgery : Official Publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter. Feb, 2006  |  Pubmed ID: 16476622

Intrathoracic great vessels injuries are usually fatal and represent a special surgical challenge. We report a successful surgical repair for blunt disruption of the three aortic arch branches in the setting of bovine arch anatomy. The repair was achieved without the use of cardiopulmonary bypass or arterial shunts. There was no clinical or radiologic evidence of neurologic abnormality after the repair.

Successful Bridge to Transplant Using the Berlin Heart Left Ventricular Assist Device in a 3-month-old Infant

The Annals of Thoracic Surgery. Mar, 2006  |  Pubmed ID: 16488739

The EXCOR Berlin Heart (Berlin Heart, Berlin, Germany) was successfully used as a pediatric left ventricular assist device as a bridge to cardiac transplantation. The pneumatically driven paracorporeal device successfully supported a 7 kg patient for 53 days until a suitable heart was obtained for transplantation.

Human Tissue-engineered Blood Vessels for Adult Arterial Revascularization

Nature Medicine. Mar, 2006  |  Pubmed ID: 16491087

There is a crucial need for alternatives to native vein or artery for vascular surgery. The clinical efficacy of synthetic, allogeneic or xenogeneic vessels has been limited by thrombosis, rejection, chronic inflammation and poor mechanical properties. Using adult human fibroblasts extracted from skin biopsies harvested from individuals with advanced cardiovascular disease, we constructed tissue-engineered blood vessels (TEBVs) that serve as arterial bypass grafts in long-term animal models. These TEBVs have mechanical properties similar to human blood vessels, without relying upon synthetic or exogenous scaffolding. The TEBVs are antithrombogenic and mechanically stable for 8 months in vivo. Histological analysis showed complete tissue integration and formation of vasa vasorum. The endothelium was confluent and positive for von Willebrand factor. A smooth muscle-specific alpha-actin-positive cell population developed within the TEBV, suggesting regeneration of a vascular media. Electron microscopy showed an endothelial basement membrane, elastogenesis and a complex collagen network. These results indicate that a completely biological and clinically relevant TEBV can be assembled exclusively from an individual's own cells.

Outcome Analysis of Donor Gender in Heart Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Apr, 2006  |  Pubmed ID: 16563978

Several studies have shown a detrimental effect of female donor gender on the survival of solid-organ transplant recipients, including heart, kidney and liver. We evaluated our own experience in heart transplantation in the cyclosporine era, since 1980, to determine the effect of donor gender on survival.

Collagen Matrices Enhance Survival of Transplanted Cardiomyoblasts and Contribute to Functional Improvement of Ischemic Rat Hearts

Circulation. Jul, 2006  |  Pubmed ID: 16820568

Cardiac cell transplantation is limited by poor graft viability. We aimed to enhance the survival of transplanted cardiomyoblasts using growth factor-supplemented collagen matrices.

Adenoviral Human BCL-2 Transgene Expression Attenuates Early Donor Cell Death After Cardiomyoblast Transplantation into Ischemic Rat Hearts

Circulation. Jul, 2006  |  Pubmed ID: 16820569

Cell transplantation for myocardial repair is limited by early cell death. Gene therapy with human Bcl-2 (hBcl-2) has been shown to attenuate apoptosis in the experimental setting. Therefore, we studied the potential benefit of hBcl-2 transgene expression on the survival of cardiomyoblast grafts in ischemic rat hearts.

Dual in Vivo Magnetic Resonance Evaluation of Magnetically Labeled Mouse Embryonic Stem Cells and Cardiac Function at 1.5 T

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Jan, 2006  |  Pubmed ID: 16315206

Cell therapy has demonstrated the potential to restore injured myocardium. A reliable in vivo imaging method to localize transplanted cells and monitor their restorative effects will enable a systematic investigation of this therapeutic modality. The dual MRI capability of imaging both magnetically labeled mouse embryonic stem cells (mESC) and their restorative effects on cardiac function in a murine model of acute myocardial infarction is demonstrated. Serial in vivo MR detection of transplanted mESC and monitoring of the mESC-treated myocardium was conducted over a 4-week period using a 1.5 T clinical scanner. During the 4-week duration, the mESC-treated myocardium demonstrated sustained improvement of the left ventricular (LV) ejection fraction and conservation of LV mass. Furthermore, no significant difference of their restorative effects on the cardiac function was created by the magnetic labeling of mESC. Thus, in vivo MRI enables simultaneous detection of transplanted mESC and their therapeutic effect on the injured myocardium.

Aortic Root Aneurysm Due to Donor Cystic Medial Degeneration After Heart-lung Transplantation

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Oct, 2006  |  Pubmed ID: 17045942

A patient presented with symptomatic aortic root enlargement 5 years after combined heart and double-lung transplantation for cystic fibrosis, requiring homograft aortic root replacement. Histologic examination of the resected aneurysm showed cystic medial degeneration with no evidence of infectious or atherosclerotic process. Surgical options and potential role of immunosuppressive therapy after homograft implantation are discussed.

Magnetic Resonance Imaging of Progressive Cardiomyopathic Changes in the Db/db Mouse

American Journal of Physiology. Heart and Circulatory Physiology. May, 2007  |  Pubmed ID: 17122193

The db/db mouse is a well-established model of diabetes. Previous reports have documented contractile dysfunction (i.e., cardiomyopathy) in these animals, although the extant literature provides limited insights into cardiac structure and function as they change over time. To better elucidate the natural history of cardiomyopathy in db/db mice, we performed cardiac magnetic resonance (CMR) scans on these animals. CMR imaging was conducted with a 4.7-T magnet on female db/db mice and control db/+ littermates at 5, 9, 13, 17, and 22 wk of age. Gated gradient echo sequences were used to obtain cineographic short-axis slices from apex to base. From these images left ventricular (LV) mass (LVM), wall thickness, end-diastolic volume (LVEDV), and ejection fraction (LVEF) were determined. Additionally, cardiac [(18)F]fluorodeoxyglucose ([(18)F]FDG) PET scanning, pressure-volume loops, and real-time quantitative PCR on db/db myocardium were performed. Relative to control, db/db mice developed significant increases in LVM and wall thickness as early as 9 wk of age. LVEDV diverged slightly later, at 13 wk. Interestingly, compared with the baseline level, LVEF in the db/db group did not decrease significantly until 22 wk. Additionally, [(18)F]FDG metabolic imaging showed a 40% decrease in glucose uptake in db/db mice. Furthermore, contractile dysfunction was observed in 15-wk db/db mice undergoing pressure-volume loops. Finally, real-time quantitative PCR revealed an age-dependent recapitulation of the fetal gene program, consistent with a myopathic process. In summary, as assessed by CMR, db/db mice develop characteristic structural and functional changes consistent with cardiomyopathy.

FK778 in Experimental Xenotransplantation: a Detailed Analysis of Drug Efficacy

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jan, 2007  |  Pubmed ID: 17234520

This study examines the efficacy of FK778 regimens for prevention of different phases of xenograft rejection.

Influence of Mast Cells on Outcome After Heterotopic Cardiac Transplantation in Rats

Transplant International : Official Journal of the European Society for Organ Transplantation. Mar, 2007  |  Pubmed ID: 17291219

Correlative data suggest that mast cells adversely affect cardiac transplantation. This study uses a mast cell-deficient rat model to directly address the role of mast cells in cardiac allotransplantation. Standardized cardiac heterotopic transplantation with cyclosporine immunosuppression was performed in mast cell-deficient and mast cell-competent rats. Rejection, ischemia, fibrosis, fibrin deposition, numbers of T-cell receptor alpha/beta positive cells, expression of transforming growth factor-beta (TGF-beta), and of endothelin-1 (ET-1) and its receptors ETA and ETB were assessed. Differences in baseline cardiac gene expression were quantified by real-time PCR in a separate group of untransplanted animals. Baseline cardiac gene expression levels of all investigated growth factors, cytokines, ET-1, ETA, and ETB were similar in mast cell-deficient and mast cell-competent rats. Surprisingly, upon heterotopic transplantation, donor heart survival was significantly reduced in mast cell-deficient rats. Moreover, in mast cell-deficient donor hearts rejection was more severe, although nonsignificant, and extracellular matrix associated TGF-beta immunoreactivity was significantly lower than in mast cell-competent donor hearts. Fibrin immunoreactive area, on the other hand, was only increased in mast cell-deficient donor hearts, but not in mast cell-competent donor hearts. Histopathological changes in all donor hearts were accompanied by increased immunoreactivity for ET-1. In conclusion, this study shows that mast cells play a protective role after cardiac transplantation.

Experimental Orthotopic Tracheal Transplantation: The Stanford Technique

Microsurgery. 2007  |  Pubmed ID: 17326196

The rat heterotopic tracheal transplantation model is widely used as an experimental model to study the development of obliterative airway disease (OAD) and to assess immunosuppressive strategies for chronic rejection. Despite its widespread application, the heterotopic transplantation model does have a number of limitations like the lack of air flow and mucociliary clearance. The present article provides a detailed description of the surgical technique for orthotopic tracheal transplantations, which may share more similarities with lung transplants in humans. The technique is easy to learn, the procedure is well tolerated by the animals, and the grafts develop OAD lesions similar to those of human obliterative bronchiolitis.

In Vivo Optical Bioluminescence Imaging of Collagen-supported Cardiac Cell Grafts

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Mar, 2007  |  Pubmed ID: 17346630

Histology-based survival assessment of cell grafts does not allow for in vivo follow-up. In this study we introduce two new experimental models for longitudinal in vivo survival studies of cardiac cell grafts using optical bioluminescence imaging.

Simplified Protocol to Isolate, Purify, and Culture Expand Mesenchymal Stem Cells

Stem Cells and Development. Feb, 2007  |  Pubmed ID: 17348808

Mesenchymal stem cells (MSCs) are widely used for experimental regenerative strategies. Due to their differentiation capacity into mesenchymal lineages, they are a potential cellular source for tissue regeneration. Because there is no specific antigen that can be used to define MSCs directly, there is no consensus about how to isolate them. Here we describe a simple protocol to isolate, purify, and culture expand murine bone marrow MSCs using magnetic cell sorting and plastic adherence. We further show that cytokine supplementation enhances MSC proliferation without jeopardizing their pluripotency.

Positron Emission Tomography Imaging of Conditional Gene Activation in the Heart

Journal of Molecular and Cellular Cardiology. Jul, 2007  |  Pubmed ID: 17467733

The Cre-loxP system has been routinely used for conditional activation and deletion of gene expression. However, the spatiotemporal manner of these events in the heart has not yet been defined by in vivo imaging. Adenovirus (1 x 10(9 )pfu) carrying the silent positron emission tomography (PET) reporter gene, herpes simplex virus type 1 thymidine kinase (HSV1-tk), was injected into the left ventricular wall of male transgenic mice (n=15) or FVB controls (n=8). Transgenic mice expressed Cre recombinase driven by a cardiac-specific alpha-myosin heavy chain (alpha-MHC) promoter. Following injection of the 9-[4-fluoro-3-(hydroxymethyl)butyl]guanine ([18F]-FHBG; 137+/-25 microCi) reporter probe, microPET imaging was used to assess the expression of HSV1-tk reporter gene in the myocardium. Two days following adenoviral injection, cardiac HSV1-tk gene activation resulted in tracer uptake of 3.20+/-0.51% ID/g for alpha-MHC-Cre and 0.05+/-0.02%ID/g for control mice (P<0.01). The in vivo results were confirmed by RT-PCR and Western blot analysis. Similar transfections were evaluated in both cardiac-specific and non-cardiac-specific cell lines. Enzyme activity showed a robust correlation (r2=0.82) between in vivo molecular imaging technique and traditional in vitro enzyme assays. With further development and validation, PET imaging will likely play an important role in the noninvasive, repetitive, and quantitative measurement of conditional gene activation in the future.

Comment on "Transplantation of Undifferentiated Murine Embryonic Stem Cells in the Heart: Teratoma Formation and Immune Response"

FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology. May, 2007  |  Pubmed ID: 17470572

Techniques for Experimental Heterotopic and Orthotopic Tracheal Transplantations - When to Use Which Model?

Transplant Immunology. Jun, 2007  |  Pubmed ID: 17493528

Different animal models have been developed to study the pathogenesis and treatment of obliterative airway disease (OAD). Here we describe the techniques of heterotopic and orthotopic tracheal transplantations in the rat, comparing the kinetics of systemic host immune response and of histopathologic OAD development.

In Vitro Comparison of the Biological Effects of Three Transfection Methods for Magnetically Labeling Mouse Embryonic Stem Cells with Ferumoxides

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Jun, 2007  |  Pubmed ID: 17534917

In vivo MRI of stem cells (SCs) is an emerging application to evaluate the role of cell therapy in restoring the injured myocardium. The high spatial and temporal resolution combined with iron-oxide-based intracellular labeling techniques will provide a sensitive, noninvasive, dual imaging modality for both cells and myocardium. In order to facilitate this novel imaging approach, much effort has been directed towards developing efficient transfection methods. While techniques utilizing poly-L-lysine (PLL), protamine sulfate (PS), and electroporation (ELP) have been proposed, the fundamental biological effects of these methods on mouse embryonic SCs (mESC) have not been investigated systematically. In this study a longitudinal in vitro evaluation of cellular viability, apoptosis, proliferation, and cardiac differentiation of magnetically labeled mESC was conducted. No significant difference was seen in these biological parameters among the three transfection methods. However, cardiac differentiation was most attenuated by ELP, and iron uptake was most effective by PS.

Molecular Imaging of Bone Marrow Mononuclear Cell Homing and Engraftment in Ischemic Myocardium

Stem Cells (Dayton, Ohio). Oct, 2007  |  Pubmed ID: 17628019

Bone marrow mononuclear cell (BMMC) therapy shows promise as a treatment for ischemic heart disease. However, the ability to monitor long-term cell fate remains limited. We hypothesized that molecular imaging could be used to track stem cell homing and survival after myocardial ischemia-reperfusion (I/R) injury. We first harvested donor BMMCs from adult male L2G85 transgenic mice constitutively expressing both firefly luciferase (Fluc) and enhanced green fluorescence protein reporter gene. Fluorescence-activated cell sorting analysis revealed approximately 0.07% of the population to consist of classic hematopoietic stem cells (lin-, thy-int, c-kit+, Sca-1+). Afterward, adult female FVB recipients (n = 38) were randomized to sham surgery or acute I/R injury. Animals in the sham (n = 16) and I/R (n = 22) groups received 5 x 10(6) of the L2G85-derived BMMCs via tail vein injection. Bioluminescence imaging (BLI) was used to track cell migration and survival in vivo for 4 weeks. BLI showed preferential homing of BMMCs to hearts with I/R injury compared with sham hearts within the first week following cell injection. Ex vivo analysis of explanted hearts by histology confirmed BLI imaging results, and quantitative real-time polymerase chain reaction (for the male Sry gene) further demonstrated a greater number of BMMCs in hearts with I/R injury compared with the sham group. Functional evaluation by echocardiography demonstrated a trend toward improved left ventricular fractional shortening in animals receiving BMMCs. Taken together, these data demonstrate that molecular imaging can be used to successfully track BMMC therapy in murine models of heart disease. Specifically, we have demonstrated that systemically delivered BMMCs preferentially home to and are retained by injured myocardium. Disclosure of potential conflicts of interest is found at the end of this article.

Pharmacological Inhibition of Epsilon PKC Suppresses Chronic Inflammation in Murine Cardiac Transplantation Model

Journal of Molecular and Cellular Cardiology. Oct, 2007  |  Pubmed ID: 17655859

Epsilon protein kinase C (epsilonPKC) plays pivotal roles in myocardial infarction and in heart failure. Although cardiac transplantation is a well-established therapy for severe heart failure, allograft rejection and host inflammatory responses limit graft function and reduce life expectancy. Here we determined whether sustained epsilonPKC inhibition beginning 3 days after transplantation suppress allograft rejection and improve cardiac transplantation using a murine heterotopic transplantation model. Hearts of FVB mice (H-2(q)) were transplanted into C57BL/6 mice (H-2(b)). Delivery of the epsilonPKC inhibitor, TAT(47-57)-epsilonV1-2 (epsilonV1-2, n=9, 20 mg/kg/day), or the carrier control peptide, TAT(47-57) (TAT, n=8), by osmotic pump began 3 days after transplantation and continued for the remaining 4 weeks. epsilonV1-2 treatment significantly improved the beating score throughout the treatment. Infiltration of macrophages and T cells into the cardiac grafts was significantly reduced and parenchymal fibrosis was decreased in animals treated with epsilonV1-2 as compared with control treatment. Finally, the rise in pro-fibrotic cytokine, TGF-beta and monocyte recruiting chemokine MCP-1 levels was almost abolished by epsilonV1-2 treatment, whereas the rise in PDGF-BB level was unaffected. These data suggest that epsilonPKC activity contributes to the chronic immune response in cardiac allograft and that an epsilonPKC-selective inhibitor, such as epsilonV1-2, could augment current therapeutic strategies to suppress inflammation and prolong graft survival in humans.

Differentiation, Survival, and Function of Embryonic Stem Cell Derived Endothelial Cells for Ischemic Heart Disease

Circulation. Sep, 2007  |  Pubmed ID: 17846325

Embryonic stem (ES) cells are distinguished by their capacity for self-renewal and pluripotency. Here we characterize the differentiation of ES cell-derived endothelial cells (ESC-ECs), use molecular imaging techniques to examine their survival in vivo, and determine the therapeutic efficacy of ESC-ECs for restoration of cardiac function after ischemic injury.

Synergistic Airway Gland Mucus Secretion in Response to Vasoactive Intestinal Peptide and Carbachol is Lost in Cystic Fibrosis

The Journal of Clinical Investigation. Oct, 2007  |  Pubmed ID: 17853942

Cystic fibrosis (CF) is caused by dysfunction of the CF transmembrane conductance regulator (CFTR), an anion channel whose dysfunction leads to chronic bacterial and fungal airway infections via a pathophysiological cascade that is incompletely understood. Airway glands, which produce most airway mucus, do so in response to both acetylcholine (ACh) and vasoactive intestinal peptide (VIP). CF glands fail to secrete mucus in response to VIP, but do so in response to ACh. Because vagal cholinergic pathways still elicit strong gland mucus secretion in CF subjects, it is unclear whether VIP-stimulated, CFTR-dependent gland secretion participates in innate defense. It was recently hypothesized that airway intrinsic neurons, which express abundant VIP and ACh, are normally active and stimulate low-level gland mucus secretion that is a component of innate mucosal defenses. Here we show that low levels of VIP and ACh produced significant mucus secretion in human glands via strong synergistic interactions; synergy was lost in glands of CF patients. VIP/ACh synergy also existed in pig glands, where it was CFTR dependent, mediated by both Cl(-) and HCO(3) (-), and clotrimazole sensitive. Loss of "housekeeping" gland mucus secretion in CF, in combination with demonstrated defects in surface epithelia, may play a role in the vulnerability of CF airways to bacterial infections.

Spatial and Temporal Kinetics of Teratoma Formation from Murine Embryonic Stem Cell Transplantation

Stem Cells and Development. Dec, 2007  |  Pubmed ID: 17896868

Pluripotent embryonic stem (ES) cells have the potential to form teratomas composed of derivatives from all three germ layers in animal models. This tumorigenic potential prevents clinical translation of ES cell research. In order to understand the biology and physiology of teratoma formation, we investigated the influence of undifferentiated ES cell number, migration, and long-term follow up after transplantation. Murine ES cells were stably transduced with a self-inactivating (SIN) lentiviral vector with a constitutive ubiquitin promoter driving a double-fusion (DF) reporter gene that consists of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP). To assess effects of cell numbers, varying numbers of ES-DF cells (1, 10, 100, 1,000, and 10,000) were injected subcutaneously into the dorsal regions of adult nude mice. To assess cell migration, 1 x 10(6) ES-DF cells were injected intramyocardially into adult Sv129 mice, and leakage to other extracardiac sites was monitored. To assess effects of long-term engraftment, 1 x 10(4) ES-DF cells were injected intramyocardially into adult nude rats, and cell survival response was monitored for 10 months. Our results show that ES-DF cells caused extracardiac teratoma in both immunocompetent and immunodeficient hosts; the lowest number of undifferentiated ES cells capable of causing teratoma was 500-1,000; and long-term engraftment could be shown for >300 days. Collectively, these results illustrate the potent tumorigenic potential of ES cells, which presents an enormous obstacle for future clinical studies.

Inhibition of Restenosis Development After Mechanical Injury: a New Field of Application for Malononitrilamides?

Cardiology. 2007  |  Pubmed ID: 17028423

To investigate the efficacy of the malononitrilamide FK778 to prevent vascular smooth muscle cell (SMC) migration/proliferation, and vascular fibrosis, the key events in restenosis development using in vivo and in vitro studies.

Genetic Modification of Embryonic Stem Cells with VEGF Enhances Cell Survival and Improves Cardiac Function

Cloning and Stem Cells. 2007  |  Pubmed ID: 18154515

Cardiac stem cell therapy remains hampered by acute donor cell death posttransplantation and the lack of reliable methods for tracking cell survival in vivo. We hypothesize that cells transfected with inducible vascular endothelial growth factor 165 (VEGF(165)) can improve their survival as monitored by novel molecular imaging techniques. Mouse embryonic stem (ES) cells were transfected with an inducible, bidirectional tetracycline (Bi-Tet) promoter driving VEGF(165) and renilla luciferase (Rluc). Addition of doxycycline induced Bi-Tet expression of VEGF(165) and Rluc significantly compared to baseline (p<0.05). Expression of VEGF(165) enhanced ES cell proliferation and inhibited apoptosis as determined by Annexin-V staining. For noninvasive imaging, ES cells were transduced with a double fusion (DF) reporter gene consisting of firefly luciferase and enhanced green fluorescence protein (Fluc-eGFP). There was a robust correlation between cell number and Fluc activity (R(2)=0.99). Analysis by immunostaining, histology, and RT-PCR confirmed that expression of Bi-Tet and DF systems did not affect ES cell self-renewal or pluripotency. ES cells were differentiated into beating embryoid bodies expressing cardiac markers such as troponin, Nkx2.5, and beta-MHC. Afterward, 5 x 10(5) cells obtained from these beating embryoid bodies or saline were injected into the myocardium of SV129 mice (n=36) following ligation of the left anterior descending (LAD) artery. Bioluminescence imaging (BLI) and echocardiography showed that VEGF(165) induction led to significant improvements in both transplanted cell survival and cardiac function (p<0.05). This is the first study to demonstrate imaging of embryonic stem cell-mediated gene therapy targeting cardiovascular disease. With further validation, this platform may have broad applications for current basic research and further clinical studies.

Pneumatic Paracorporeal Ventricular Assist Device in Infants and Children: Initial Stanford Experience

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Feb, 2008  |  Pubmed ID: 18267223

Mechanical circulatory support with the Berlin Heart EXCOR pediatric ventricular assist device (VAD) has been used successfully in Europe for children with cardiac failure. Eighty-seven devices have been placed in North America through February 2007. We describe our single-center experience in 8 children.

Introducing the First Polymer-free Leflunomide Eluting Stent

Atherosclerosis. Sep, 2008  |  Pubmed ID: 18295768

We here describe the pharmacological characteristic, in vivo efficacy, and in vitro mechanisms of a polymer-free leflunomide eluting stent in comparison to its rapamycin-coated equivalent.

Prevention and Inhibition but Not Reversion of Chronic Allograft Vasculopathy by FK778

Transplantation. Mar, 2008  |  Pubmed ID: 18360270

This study aimed at investigating the efficacy of the novel immunosuppressant FK778 to prevent the development and progression of chronic allograft vasculopathy (CAV).

Novel Immunosuppression: R348, a JAK3- and Syk-inhibitor Attenuates Acute Cardiac Allograft Rejection

Transplantation. Mar, 2008  |  Pubmed ID: 18360272

Janus kinase (JAK)3 is crucial for signal transduction downstream of various cytokine receptors in immune cells. This is the first report on the novel JAK3 inhibitor R348.

In Vivo Imaging of Embryonic Stem Cells Reveals Patterns of Survival and Immune Rejection Following Transplantation

Stem Cells and Development. Dec, 2008  |  Pubmed ID: 18491958

Embryonic stem cell (ESC)-based transplantation is considered a promising novel therapy for a variety of diseases. This is bolstered by the suggested immune-privileged properties of ESCs. In this study, we used in vivo bioluminescent imaging (BLI) to non-invasively track the fate of transplanted murine ESCs (mESCs), which are stably transduced with a double fusion reporter gene consisting of firefly luciferase (FLuc) and enhanced green fluorescent protein (eGFP). Following syngeneic intramuscular transplantation of 1 x 10(6) mESCs, the cells survived and differentiated into teratomas. In contrast, allogeneic mESC transplants were infiltrated by a variety of inflammatory cells, leading to rejection within 28 days. Acceleration of rejection was observed when mESCs were allotransplanted following prior sensitization of the host. Finally, we demonstrate that the mESC derivatives were more rapidly rejected compared to undifferentiated mESCs. These data show that mESCs do not retain immune-privileged properties in vivo and are subject to immunological rejection as assessed by novel molecular imaging approaches.

A Novel Platform Device for Rodent Echocardiography

ILAR Journal / National Research Council, Institute of Laboratory Animal Resources. 2008  |  Pubmed ID: 18506056

Acquisition of echocardiographic data from rodents is subject to wide variability due to variations in technique. We hypothesize that a dedicated imaging platform can aid in standardization of technique and improve the quality of images obtained. We constructed a device consisting of a boom-mounted steel platform frame (25 x 35 x 3 cm) on which a transparent polyethylene membrane is mounted. The animal is placed onto the membrane and receives continual inhaled anesthesia via an integrated port. The membrane allows for probe positioning from beneath the animal to obtain standard echo-views in left lateral decubitus or prone positions. The frame can be set at any desired angle ranging from 0 to 360 degrees along either the long or short axis. Adult male Sprague-Dawley rats (n = 5) underwent echocardiography (General Electric, Vivid 7, 14 MHz) using the platform. The device allowed for optimal positioning of animals for a variety of standard echocardiographic measurements. Evaluations among all animals showed minimal variability between two different operators and time points. We tested the feasibility of the device for supporting the assessment of cardiac function in a disease model by evaluating a separate cohort of adult male spontaneously hypertensive rats (n = 5) that underwent left anterior descending coronary artery ligation. Serial echocardiography demonstrated statistically significant decreases of fractional shortening and ejection fraction (p < 0.01) 240 days after surgery. Our novel imaging platform allowed for consistent collection of high-quality echocardiographic data from rats. Future studies will focus on improving this technology to allow for standardized high-throughput echocardiographic analysis in small animal models of disease.

Immunosuppressive Therapy Mitigates Immunological Rejection of Human Embryonic Stem Cell Xenografts

Proceedings of the National Academy of Sciences of the United States of America. Sep, 2008  |  Pubmed ID: 18728188

Given their self-renewing and pluripotent capabilities, human embryonic stem cells (hESCs) are well poised as a cellular source for tissue regeneration therapy. However, the host immune response against transplanted hESCs is not well characterized. In fact, controversy remains as to whether hESCs have immune-privileged properties. To address this issue, we used in vivo bioluminescent imaging to track the fate of transplanted hESCs stably transduced with a double-fusion reporter gene consisting of firefly luciferase and enhanced GFP. We show that survival after transplant is significantly limited in immunocompetent as opposed to immunodeficient mice. Repeated transplantation of hESCs into immunocompetent hosts results in accelerated hESC death, suggesting an adaptive donor-specific immune response. Our data demonstrate that transplanted hESCs trigger robust cellular and humoral immune responses, resulting in intragraft infiltration of inflammatory cells and subsequent hESC rejection. Moreover, we have found CD4(+) T cells to be an important modulator of hESC immune-mediated rejection. Finally, we show that immunosuppressive drug regimens can mitigate the anti-hESC immune response and that a regimen of combined tacrolimus and sirolimus therapies significantly prolongs survival of hESCs for up to 28 days. Taken together, these data suggest that hESCs are immunogenic, trigger both cellular and humoral-mediated pathways, and, as a result, are rapidly rejected in xenogeneic hosts. This process can be mitigated by a combined immunosuppressive regimen as assessed by molecular imaging approaches.

Comparison of Different Adult Stem Cell Types for Treatment of Myocardial Ischemia

Circulation. Sep, 2008  |  Pubmed ID: 18824743

A comparative analysis of the efficacy of different cell candidates for the treatment of heart disease remains to be described. This study is designed to evaluate the therapeutic efficacy of 4 cell types in a murine model of myocardial infarction.

Short Hairpin RNA Interference Therapy for Ischemic Heart Disease

Circulation. Sep, 2008  |  Pubmed ID: 18824759

During hypoxia, upregulation of hypoxia inducible factor-1 alpha transcriptional factor can activate several downstream angiogenic genes. However, hypoxia inducible factor-1 alpha is naturally degraded by prolyl hydroxylase-2 (PHD2) protein. Here we hypothesize that short hairpin RNA (shRNA) interference therapy targeting PHD2 can be used for treatment of myocardial ischemia and this process can be followed noninvasively by molecular imaging.

Transcriptional and Functional Profiling of Human Embryonic Stem Cell-derived Cardiomyocytes

PloS One. 2008  |  Pubmed ID: 18941512

Human embryonic stem cells (hESCs) can serve as a potentially limitless source of cells that may enable regeneration of diseased tissue and organs. Here we investigate the use of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) in promoting recovery from cardiac ischemia reperfusion injury in a mouse model. Using microarrays, we have described the hESC-CM transcriptome within the spectrum of changes that occur between undifferentiated hESCs and fetal heart cells. The hESC-CMs expressed cardiomyocyte genes at levels similar to those found in 20-week fetal heart cells, making this population a good source of potential replacement cells in vivo. Echocardiographic studies showed significant improvement in heart function by 8 weeks after transplantation. Finally, we demonstrate long-term engraftment of hESC-CMs by using molecular imaging to track cellular localization, survival, and proliferation in vivo. Taken together, global gene expression profiling of hESC differentiation enables a systems-based analysis of the biological processes, networks, and genes that drive hESC fate decisions, and studies such as this will serve as the foundation for future clinical applications of stem cell therapies.

Multimodal Evaluation of in Vivo Magnetic Resonance Imaging of Myocardial Restoration by Mouse Embryonic Stem Cells

The Journal of Thoracic and Cardiovascular Surgery. Oct, 2008  |  Pubmed ID: 18954646

Mouse embryonic stem cells have demonstrated potential to restore infarcted myocardium after acute myocardial infarction. Although the underlying mechanism remains controversial, magnetic resonance imaging has provided reliable in vivo assessment of functional recovery after cellular transplants. Multimodal comparison of the restorative effects of mouse embryonic stem cells and mouse embryonic fibroblasts was performed to validate magnetic resonance imaging data and provide mechanistic insight.

In Vivo Serial Evaluation of Superparamagnetic Iron-oxide Labeled Stem Cells by Off-resonance Positive Contrast

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Dec, 2008  |  Pubmed ID: 19030159

MRI is emerging as a diagnostic modality to track iron-oxide-labeled stem cells. This study investigates whether an off-resonance (OR) pulse sequence designed to generate positive contrast at 1.5T can assess the location, quantity, and viability of delivered stem cells in vivo. Using mouse embryonic stem cell transfected with luciferase reporter gene (luc-mESC), multimodality validation of OR signal was conducted to determine whether engraftment parameters of superparamagnetic iron-oxide labeled luc-mESC (SPIO-luc-mESC) could be determined after cell transplantation into the mouse hindlimb. A significant increase in signal- and contrast-to-noise of the SPIO-luc-mESC was achieved with the OR technique when compared to a gradient recalled echo (GRE) sequence. A significant correlation between the quantity of SPIO-luc-mESC and OR signal was observed immediately after transplantation (R(2) = 0.74, P < 0.05). The assessment of transplanted cell viability by bioluminescence imaging (BLI) showed a significant increase of luciferase activities by day 16, while the MRI signal showed no difference. No significant correlation between BLI and MRI signals of cell viability was observed. In conclusion, using an OR sequence the precise localization and quantitation of SPIO-labeled stem cells in both space and time were possible. However, the OR sequence did not allow evaluation of cell viability.

Multimodality Evaluation of the Viability of Stem Cells Delivered into Different Zones of Myocardial Infarction

Circulation. Cardiovascular Imaging. Jul, 2008  |  Pubmed ID: 19808509

We tested the hypothesis that multimodality imaging of mouse embryonic stem cells (mESCs) provides accurate assessment of cellular location, viability, and restorative potential after transplantation into different zones of myocardial infarction.

In Vivo Genetic Profiling and Cellular Localization of Apelin Reveals a Hypoxia-sensitive, Endothelial-centered Pathway Activated in Ischemic Heart Failure

American Journal of Physiology. Heart and Circulatory Physiology. Jan, 2008  |  Pubmed ID: 17906101

Signaling by the peptide ligand apelin and its cognate G protein-coupled receptor APJ has a potent inotropic effect on cardiac contractility and modulates systemic vascular resistance through nitric oxide-dependent signaling. In addition, there is evidence for counterregulation of the angiotensin and vasopressin pathways. Regulatory stimuli of the apelin-APJ pathway are of obvious importance but remain to be elucidated. To better understand the physiological response of apelin-APJ to disease states such as heart failure and to elucidate the mechanism by which such a response might occur, we have used the murine model of left anterior descending coronary artery ligation-induced ischemic cardiac failure. To identify the key cells responsible for modulation and production of apelin in vivo, we have created a novel apelin-lacZ reporter mouse. Data from these studies demonstrate that apelin and APJ are upregulated in the heart and skeletal muscle following myocardial injury and suggest that apelin expression remains restricted to the endothelium. In cardiac failure, endothelial apelin expression correlates with other hypoxia-responsive genes, and in healthy animals both apelin and APJ are markedly upregulated in various tissues following systemic hypoxic exposure. Experiments with cultured endothelial cells in vitro show apelin mRNA and protein levels to be increased by hypoxia, through a hypoxia-inducible factor-mediated pathway. These studies suggest that apelin-expressing endothelial cells respond to conditions associated with heart failure, possibly including local tissue hypoxia, and modulate apelin-APJ expression to regulate cardiovascular homeostasis. The apelin-APJ pathway may thus provide a mechanism for systemic endothelial monitoring of tissue perfusion and adaptive regulation of cardiovascular function.

Effect of Work-hour Restriction on Operative Experience in Cardiothoracic Surgical Residency Training

The Journal of Thoracic and Cardiovascular Surgery. Mar, 2009  |  Pubmed ID: 19258094

Resident work-hour regulations were instituted to improve patient care during resident training. Although initial data have not shown the intended benefit of limiting resident work hours, concern has developed as to whether resident operative experience has significantly decreased since instituting the work-hour restrictions.

Comparison of Transplantation of Adipose Tissue- and Bone Marrow-derived Mesenchymal Stem Cells in the Infarcted Heart

Transplantation. Mar, 2009  |  Pubmed ID: 19295307

Mesenchymal stem cells hold promise for cardiovascular regenerative therapy. Derivation of these cells from the adipose tissue might be easier compared with bone marrow. However, the in vivo fate and function of adipose stromal cells (ASC) in the infarcted heart has never been compared directly to bone marrow-derived mesenchymal cells (MSC).

A Novel JAK3 Inhibitor, R348, Attenuates Chronic Airway Allograft Rejection

Transplantation. Mar, 2009  |  Pubmed ID: 19295308

This study aimed at investigating the role of a novel JAK3 inhibitor, R348, in the prevention of chronic airway allograft rejection.

Imaging Survival and Function of Transplanted Cardiac Resident Stem Cells

Journal of the American College of Cardiology. Apr, 2009  |  Pubmed ID: 19341866

The goal of this study is to characterize resident cardiac stem cells (CSCs) and investigate their therapeutic efficacy in myocardial infarction by molecular imaging methods.

Imaging Gene Expression in Human Mesenchymal Stem Cells: from Small to Large Animals

Radiology. Jul, 2009  |  Pubmed ID: 19366903

To evaluate the feasibility of reporter gene imaging in implanted human mesenchymal stem cells (MSCs) in porcine myocardium by using clinical positron emission tomography (PET)-computed tomography (CT) scanning.

Substance P Stimulates Human Airway Submucosal Gland Secretion Mainly Via a CFTR-dependent Process

The Journal of Clinical Investigation. May, 2009  |  Pubmed ID: 19381016

Chronic bacterial airway infections are the major cause of mortality in cystic fibrosis (CF). Normal airway defenses include reflex stimulation of submucosal gland mucus secretion by sensory neurons that release substance P (SubP). CFTR is an anion channel involved in fluid secretion and mutated in CF; the role of CFTR in secretions stimulated by SubP is unknown. We used optical methods to measure SubP-mediated secretion from human submucosal glands in lung transplant tissue. Glands from control but not CF subjects responded to mucosal chili oil. Similarly, serosal SubP stimulated secretion in more than 60% of control glands but only 4% of CF glands. Secretion triggered by SubP was synergistic with vasoactive intestinal peptide and/or forskolin but not with carbachol; synergy was absent in CF glands. Pig glands demonstrated a nearly 10-fold greater response to SubP. In 10 of 11 control glands isolated by fine dissection, SubP caused cell volume loss, lumen expansion, and mucus flow, but in 3 of 4 CF glands, it induced lumen narrowing. Thus, in CF, the reduced ability of mucosal irritants to stimulate airway gland secretion via SubP may be another factor that predisposes the airways to infections.

Manganese-guided Cellular MRI of Human Embryonic Stem Cell and Human Bone Marrow Stromal Cell Viability

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Oct, 2009  |  Pubmed ID: 19526508

This study investigated the ability of MnCl(2) as a cellular MRI contrast agent to determine the in vitro viability of human embryonic stem cells (hESC) and human bone marrow stromal cells (hBMSC). Basic MRI parameters including T(1) and T(2) values of MnCl(2)-labeled hESC and hBMSC were measured and viability signal of manganese (Mn(2+))-labeled cells was validated. Furthermore, the biological activity of Ca(2+)-channels was modulated utilizing both Ca(2+)-channel agonist and antagonist to evaluate concomitant signal changes. Metabolic effects of MnCl(2)-labeling were also assessed using assays for cell viability, proliferation, and apoptosis. Finally, in vivo Mn(2+)-guided MRI of the transplanted hESC was successfully achieved and validated by bioluminescence imaging.

Effects of Cell Number on Teratoma Formation by Human Embryonic Stem Cells

Cell Cycle (Georgetown, Tex.). Aug, 2009  |  Pubmed ID: 19597339

Teratoma formation is a critical obstacle to safe clinical translation of human embryonic stem (ES) cell-based therapies in the future. As current methods of isolation are unable to yield 100% pure population of differentiated cells from a pluripotent donor source, potential development of these tumors is a significant concern. Here we used non-invasive reporter gene imaging to investigate the relationship between human ES cell number and teratoma formation in a xenogenic model of ES cell transplantation. Human ES cells (H9 line) were stably transduced with a double fusion (DF) reporter construct containing firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP) driven by a human ubiquitin promoter. Immunodeficient mice received intramyocardial (n = 35) or skeletal muscle (n = 35) injection of 1 x 10(2), 1 x 10(3), 1 x 10(4), 1 x 10(5) or 1 x 10(6) DF positive ES cells suspended in saline for myocardium and Matrigel for skeletal muscle. Cell survival and proliferation were monitored via bioluminescence imaging (BLI) for an 8 week period following transplantation. Mice negative for Fluc signal after 8 weeks were followed out to day 365 to confirm tumor absence. Significantly, in this study, a minimum of 1 x 10(5) ES cells in the myocardium and 1 x 10(4) cells in the skeletal muscle was observed to be requisite for teratoma development, suggesting that human ES cell number may be a critical factor in teratoma formation. Engraftment and tumor occurrence were also observed to be highly dependent on ES cell number. We anticipate these results should yield useful insights to the safe and reliable application of human ES cell derivatives in the clinic.

Novel Minicircle Vector for Gene Therapy in Murine Myocardial Infarction

Circulation. Sep, 2009  |  Pubmed ID: 19752373

Conventional plasmids for gene therapy produce low-level and short-term gene expression. In this study, we develop a novel nonviral vector that robustly and persistently expresses the hypoxia-inducible factor-1 alpha (HIF-1alpha) therapeutic gene in the heart, leading to functional benefits after myocardial infarction.

Hepatocyte Growth Factor or Vascular Endothelial Growth Factor Gene Transfer Maximizes Mesenchymal Stem Cell-based Myocardial Salvage After Acute Myocardial Infarction

Circulation. Sep, 2009  |  Pubmed ID: 19752375

Mesenchymal stem cell (MSC)-based regenerative strategies were investigated to treat acute myocardial infarction and improve left ventricular function.

NAChRs Mediate Human Embryonic Stem Cell-derived Endothelial Cells: Proliferation, Apoptosis, and Angiogenesis

PloS One. 2009  |  Pubmed ID: 19753305

Many patients with ischemic heart disease have cardiovascular risk factors such as cigarette smoking. We tested the effect of nicotine (a key component of cigarette smoking) on the therapeutic effects of human embryonic stem cell-derived endothelial cells (hESC-ECs).

Alternative Technique for Salvage of Donor Lungs with Insufficient Atrial Cuffs

The Annals of Thoracic Surgery. Oct, 2009  |  Pubmed ID: 19766854

Inadequate left atrial cuff surrounding donor pulmonary veins may present a technical challenge for successful lung transplantation. A simple technique for construction of venous anastomoses during lung transplantation when donor atrial cuff is lacking involves circumferential incorporation of surrounding donor pericardium into the anastomosis without directly suturing or augmenting donor venous structures.

Poor Functional Recovery After Transplantation of Diabetic Bone Marrow Stem Cells in Ischemic Myocardium

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Nov, 2009  |  Pubmed ID: 19782602

Autologous bone marrow mononuclear cell (BMMC) therapy has shown promise for improving cardiac function after myocardial infarction. The efficiency of such therapy for diabetic patients remains unknown.

Feeder-free Derivation of Induced Pluripotent Stem Cells from Adult Human Adipose Stem Cells

Proceedings of the National Academy of Sciences of the United States of America. Sep, 2009  |  Pubmed ID: 19805220

Ectopic expression of transcription factors can reprogram somatic cells to a pluripotent state. However, most of the studies used skin fibroblasts as the starting population for reprogramming, which usually take weeks for expansion from a single biopsy. We show here that induced pluripotent stem (iPS) cells can be generated from adult human adipose stem cells (hASCs) freshly isolated from patients. Furthermore, iPS cells can be readily derived from adult hASCs in a feeder-free condition, thereby eliminating potential variability caused by using feeder cells. hASCs can be safely and readily isolated from adult humans in large quantities without extended time for expansion, are easy to maintain in culture, and therefore represent an ideal autologous source of cells for generating individual-specific iPS cells.

Functional and Transcriptional Characterization of Human Embryonic Stem Cell-derived Endothelial Cells for Treatment of Myocardial Infarction

PloS One. 2009  |  Pubmed ID: 20046878

Differentiation of human embryonic stem cells into endothelial cells (hESC-ECs) has the potential to provide an unlimited source of cells for novel transplantation therapies of ischemic diseases by supporting angiogenesis and vasculogenesis. However, the endothelial differentiation efficiency of the conventional embryoid body (EB) method is low while the 2-dimensional method of co-culturing with mouse embryonic fibroblasts (MEFs) require animal product, both of which can limit the future clinical application of hESC-ECs. Moreover, to fully understand the beneficial effects of stem cell therapy, investigators must be able to track the functional biology and physiology of transplanted cells in living subjects over time.

IL-17 Contributes to the Development of Chronic Rejection in a Murine Heart Transplant Model

Journal of Clinical Immunology. Mar, 2010  |  Pubmed ID: 20130970

Although interleukin-17 (IL-17) has been reported to participate in the pathogenesis of infectious, autoimmune and allergic disorders, the precise role in allograft rejection remains uncertain. This study illustrates that IL-17 contributes to the pathogenesis of chronic allograft rejection.

A Nonviral Minicircle Vector for Deriving Human IPS Cells

Nature Methods. Mar, 2010  |  Pubmed ID: 20139967

Owing to the risk of insertional mutagenesis, viral transduction has been increasingly replaced by nonviral methods to generate induced pluripotent stem cells (iPSCs). We report the use of 'minicircle' DNA, a vector type that is free of bacterial DNA and capable of high expression in cells, for this purpose. Here we use a single minicircle vector to generate transgene-free iPSCs from adult human adipose stem cells.

Non-volume-loaded Heart Provides a More Relevant Heterotopic Transplantation Model

Transplant Immunology. May, 2010  |  Pubmed ID: 20403439

We aimed to compare two techniques of heterotopic heart transplantation in rats. Non-volume-loaded (NL) and volume-loaded (VL) models were tested for their physiologic and immunologic properties to assess their suitability for transplant studies.

Review of Heart-lung Transplantation at Stanford

The Annals of Thoracic Surgery. Jul, 2010  |  Pubmed ID: 20609821

Long-term survival after heart-lung transplantation was first achieved in 1981 at Stanford and a total of 217 heart-lung transplantations had been performed by June 2008. This review summarizes Stanford's cumulative experience with heart-lung transplantation, demonstrates the progress that has been made, and discusses past and persistent problems. Diagnostic tools and treatment options for infectious diseases and rejection have changed and patient survival markedly improved over the almost three decades. Eight patients lived longer than 20 years. Further options to treat infections and strategies to control bronchiolitis obliterans syndrome, the main causes of early and long-term mortality, respectively, are required to achieve routine long-term survival.

Micro-CT for Characterization of Murine CV Disease Models

JACC. Cardiovascular Imaging. Jul, 2010  |  Pubmed ID: 20633858

MicroRNA-210 As a Novel Therapy for Treatment of Ischemic Heart Disease

Circulation. Sep, 2010  |  Pubmed ID: 20837903

MicroRNAs are involved in various critical functions, including the regulation of cellular differentiation, proliferation, angiogenesis, and apoptosis. We hypothesize that microRNA-210 can rescue cardiac function after myocardial infarction by upregulation of angiogenesis and inhibition of cellular apoptosis in the heart.

Sustained Inhibition of Epsilon Protein Kinase C Inhibits Vascular Restenosis After Balloon Injury and Stenting

Circulation. Sep, 2010  |  Pubmed ID: 20837910

ε protein kinase C (εPKC) is involved in vascular smooth muscle cell (VSMC) activation, but little is known about its function in vascular pathology. We aimed at assessing the role of εPKC in the development of restenosis.

Role of Molecular Imaging in Stem Cell Therapy for Myocardial Restoration

Trends in Cardiovascular Medicine. Aug, 2010  |  Pubmed ID: 22137639

During the past two decades, stem cells have created enthusiasm as a regenerative therapy for ischemic heart disease. Transplantation of bone marrow stem cells, skeletal myoblasts, and endothelial progenitor cells has shown to improve myocardial function after infarction. Recently, attention has focused on the potential use of embryonic stem cells and induced pluripotent stem cells because they possess the capacity to differentiate into various cell types, including cardiac and endothelial cells. Clinical trials have shown positive effects on the functional recovery of heart after myocardial infarction and have answered questions on timing, dosage, and cell delivery route of stem cells such as those derived from bone marrow. Despite the current advances in stem cell research, one main hurdle remains the lack of reliable information about the fate of cell engraftment, survival, and proliferation after transplantation. This review discusses the different cell types used in cardiac cell therapy as well as molecular imaging modalities relevant to survival issues.

The Role of Recipient Mast Cells in Acute and Chronic Cardiac Allograft Rejection in C57BL/6-KitW-sh/W-sh Mice

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Apr, 2010  |  Pubmed ID: 19818646

Mast cells are hypothesized to promote rejection and adverse remodeling in cardiac allografts. In contrast, it has been reported that mast cells may enhance cardiac allograft survival in rats. We used C57BL/6-Kit(W-sh/W-sh) mast cell-deficient and corresponding wild-type mice to investigate possible contributions of recipient mast cells to acute or chronic cardiac allograft rejection.

Mechanisms Behind Local Immunosuppression Using Inhaled Tacrolimus in Preclinical Models of Lung Transplantation

American Journal of Respiratory Cell and Molecular Biology. Oct, 2010  |  Pubmed ID: 19880819

Inhaled immunosuppression with tacrolimus (TAC) is a novel strategy after lung transplantation. Here we investigate the feasibility of tacrolimus delivery via aerosol, assess its immunosuppressive efficacy, reveal possible mechanisms of action, and evaluate its airway toxicity. Rats received 4 mg/kg TAC via oral or inhaled (AER) administration. Pharmacokinetic properties were compared, and in vivo airway toxicity was assessed. Full-thickness human airway epithelium (AE) was grown in vitro at an air-liquid interface. Equal TAC doses (10-1,000 ng) were either added to the bottom chamber (MED) or aerosolized for gas-phase exposure (AER). Airway epithelium TAC absorption, cell toxicity, and interactions of TAC with NFκB activation were studied. Single-photon emission computed tomography demonstrated a linear tracer accumulation within the lungs during TAC inhalation. The AER TAC generated higher lung-tissue concentrations, but blood concentrations that were 11 times lower. Airway histology and gene expression did not reveal drug toxicity after 3 weeks of treatment. In vitro AE exposed to TAC at 10-1,000 ng, orally or AER, maintained its pseudostratified morphology, did not show cell toxicity, and maintained its epithelial integrity, with tight junction formation. The TAC AER-treated AE absorbed the drug from the apical surface and generated lower-chamber TAC concentrations sufficient to suppress activated lymphocytes. Tacrolimus AER was superior to TAC MED at preventing AE IFN-γ, IL-10, IL-13, monocyte chemoattractant protein-1 chemokine (C-C motif) ligand 5 (RANTES) and TNF-α up-regulation. Tacrolimus inhibited airway epithelial cell NFκB activation. In conclusion, TAC can be delivered easily and effectively into the lungs without causing airway toxicity, decreases inflammatory AE cytokine production, and inhibits NFκB activation.

Timing of Bone Marrow Cell Delivery Has Minimal Effects on Cell Viability and Cardiac Recovery After Myocardial Infarction

Circulation. Cardiovascular Imaging. Jan, 2010  |  Pubmed ID: 19920031

Despite ongoing clinical trials, the optimal time for delivery of bone marrow mononuclear cells (BMCs) after myocardial infarction is unclear. We compared the viability and effects of transplanted BMCs on cardiac function in the acute and subacute inflammatory phases of myocardial infarction.

A Novel Cardioprotective Agent in Cardiac Transplantation: Metformin Activation of AMP-activated Protein Kinase Decreases Acute Ischemia-reperfusion Injury and Chronic Rejection

The Yale Journal of Biology and Medicine. Dec, 2011  |  Pubmed ID: 22180679

The main cause of mortality after the first year from cardiac transplantation is cardiac allograft vasculopathy (CAV), which leads to chronic rejection of the heart. To improve long-term outcomes in cardiac transplantation, treatments to prevent or diminish CAV are actively being researched. Ischemia-reperfusion (I-R) injury has been shown to be the strongest alloantigen-independent factor in the development of CAV. Here, we investigate the use of metformin in murine cardiac transplantation models as a novel cardioprotective agent to limit acute I-R injury and subsequent chronic rejection. We show that metformin treatment activates AMP-activated kinase (AMPK) in vitro and in vivo. In the acute transplantation model, metformin activation of AMPK resulted in significantly decreased apoptosis in cardiac allografts on postoperative day (POD) 1 and 8. In the chronic transplantation model, metformin pretreatment of allografts led to significantly improved graft function and significantly decreased CAV, as measured on POD 52. Taken together, our results in the acute and chronic rejection studies suggest a potential cardioprotective mechanism for metformin; we demonstrate a correlation between metformin-induced decrease in acute I-R injury and metformin-related decrease in chronic rejection. Thus, one of the ways by which metformin and AMPK activation may protect the transplanted heart from chronic rejection is by decreasing initial I-R injury inherent in donor organ preservation and implantation. Our findings suggest novel therapeutic strategies for minimizing chronic cardiac rejection via the use of metformin- and AMPK-mediated pathways to suppress acute I-R injury.

Theranostic Effect of Serial Manganese-enhanced Magnetic Resonance Imaging of Human Embryonic Stem Cell Derived Teratoma

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Dec, 2011  |  Pubmed ID: 22190225

Although human embryonic stem cell (hESC) hold therapeutic potential, teratoma formation has deterred clinical translation. Manganese (Mn(2+) ) enters metabolically active cells through voltage-gated calcium channels and subsequently, induces T(1) shortening. We hypothesized that serial manganese-enhanced MRI would have theranostic effect to assess hESC survival, teratoma formation, and hESC-derived teratoma reduction through intracellular accumulation of Mn(2+) . Firefly luciferase transduced hESCs (hESC-Lucs) were transplanted into severe combined immunodeficient mouse hindlimbs to form teratoma. The chemotherapy group was injected with MnCl(2) intraperitoneally three times a week. The control group was given MnCl(2) only prior to manganese-enhanced MRI. Longitudinal evaluation by manganese-enhanced MRI and bioluminescence imaging was performed. The chemotherapy group showed significant reduction in the teratoma volume and luciferase activity at weeks 6 and 8. Histology revealed increased proportion of dead cells and caspase 3 positive cells in the chemotherapy group. Systemic administration of MnCl(2) enabled simultaneous monitoring and elimination of hESC-derived teratoma cells by higher intracellular accumulation of Mn(2+) . Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.

Interleukin-16 Deficiency Suppresses the Development of Chronic Rejection in Murine Cardiac Transplantation Model

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Dec, 2011  |  Pubmed ID: 22055099

IL-16 promotes the recruitment of various cells expressing CD4, a receptor for IL-16. The precise role of IL-16 in transplant rejection remains unknown; therefore, the present study investigated the contribution of IL-16 to the development of chronic rejection in heart transplants.

Immunogenicity and Immunomodulatory Properties of Umbilical Cord Lining Mesenchymal Stem Cells

Cell Transplantation. 2011  |  Pubmed ID: 21054940

We here present an immunologic head-to-head comparison between human umbilical cord lining mesenchymal stem cells (clMSCs) and adult bone marrow MSCs (bmMSCs) from patients >65 years of age. clMSCs had significantly lower HLA class I expression, higher production of tolerogenic TGF-β and IL-10, and showed significantly faster proliferation. In vitro activation of allogeneic lymphocytes and xenogeneic in vivo immune activation was significantly stronger with bmMSCs, whereas immune recognition of clMSCs was significantly weaker. Thus, bmMSCs were more quickly rejected in immunocompetent mice. IFN-γ at 25 ng/ml increased both immunogenicity by upregulation of HLA class I/ HLA-DR expression and tolerogenicity by increasing intracellular HLA-G and surface HLA-E expression, augmenting TGF-β and IL-10 release, and inducing indoleamine 2,3-dioxygenase (IDO) expression. Higher concentrations of IFN-γ (>50 ng/ml) further enhanced the immunosuppressive phenotype of clMSCs, more strongly downregulating HLA-DR expression and further increasing IDO production (at 500 ng/ml). The net functional immunosuppressive efficacy of MSCs was tested in mixed lymphocyte cultures. Although both clMSCs and bmMSCs significantly reduced in vitro immune activation, clMSCs were significantly more effective than bmMSCs. The veto function of both MSC lines was enhanced in escalating IFN-γ environments. In conclusion, clMSCs show a more beneficial immunogeneic profile and stronger overall immunosuppressive potential than aged bmMSCs.

Pretreatment with Angiotensin-converting Enzyme Inhibitor Improves Doxorubicin-induced Cardiomyopathy Via Preservation Of Mitochondrial Function

The Journal of Thoracic and Cardiovascular Surgery. Aug, 2011  |  Pubmed ID: 21094500

Doxorubicin is a widely used chemotherapy drug, but its application is associated with cardiotoxicity. Free radical generation and mitochondrial dysfunction are thought to contribute to doxorubicin-induced cardiac failure. Angiotensin-converting enzyme inhibitors are commonly used as cardioprotective agents and have recently been shown in clinical studies to be efficacious in the prevention of anthracycline-induced heart failure. This study evaluated a mechanism for these protective effects by testing the ability of the angiotensin-converting enzyme inhibitor enalapril to preserve mitochondrial function in a model of chronic doxorubicin treatment in rats.

Generation of Adult Human Induced Pluripotent Stem Cells Using Nonviral Minicircle DNA Vectors

Nature Protocols. Jan, 2011  |  Pubmed ID: 21212777

Human induced pluripotent stem cells (hiPSCs) derived from patient samples have tremendous potential for innovative approaches to disease pathology investigation and regenerative medicine therapies. However, most hiPSC derivation techniques use integrating viruses, which may leave residual transgene sequences as part of the host genome, thereby unpredictably altering cell phenotype in downstream applications. In this study, we describe a protocol for hiPSC derivation by transfection of a simple, nonviral minicircle DNA construct into human adipose stromal cells (hASCs). Minicircle DNA vectors are free of bacterial DNA and thus capable of high expression in mammalian cells. Their repeated transfection into hASCs, abundant somatic cell sources that are amenable to efficient reprogramming, results in transgene-free hiPSCs. This protocol requires only readily available molecular biology reagents and expertise, and produces hiPSC colonies from an adipose tissue sample in ∼4 weeks.

Single Cell Transcriptional Profiling Reveals Heterogeneity of Human Induced Pluripotent Stem Cells

The Journal of Clinical Investigation. Mar, 2011  |  Pubmed ID: 21317531

Human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) are promising candidate cell sources for regenerative medicine. However, despite the common ability of hiPSCs and hESCs to differentiate into all 3 germ layers, their functional equivalence at the single cell level remains to be demonstrated. Moreover, single cell heterogeneity amongst stem cell populations may underlie important cell fate decisions. Here, we used single cell analysis to resolve the gene expression profiles of 362 hiPSCs and hESCs for an array of 42 genes that characterize the pluripotent and differentiated states. Comparison between single hESCs and single hiPSCs revealed markedly more heterogeneity in gene expression levels in the hiPSCs, suggesting that hiPSCs occupy an alternate, less stable pluripotent state. hiPSCs also displayed slower growth kinetics and impaired directed differentiation as compared with hESCs. Our results suggest that caution should be exercised before assuming that hiPSCs occupy a pluripotent state equivalent to that of hESCs, particularly when producing differentiated cells for regenerative medicine aims.

Prevention of Transplant Coronary Artery Disease by Prenylation Inhibitors

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation. Jul, 2011  |  Pubmed ID: 21458297

In this study we systematically dissect the prenylation pathway to better define the mechanism behind statin inhibition in chronic allograft rejection in heart transplants, or transplant coronary artery disease (TCAD).

In Vivo Molecular MRI of Cell Survival and Teratoma Formation Following Embryonic Stem Cell Transplantation into the Injured Murine Myocardium

Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. Nov, 2011  |  Pubmed ID: 21604295

Embryonic stem cells (ESCs) have shown the potential to restore cardiac function after myocardial injury. Superparamagnetic iron oxide nanoparticles (SPIO) have been widely employed to label ESCs for cellular MRI. However, nonspecific intracellular accumulation of SPIO limits long-term in vivo assessment of the transplanted cells. To overcome this limitation, a novel reporter gene (RG) has been developed to express antigens on the ESC surface. By employing SPIO-conjugated monoclonal antibody against these antigens (SPIO-MAb), the viability of transplanted ESCs can be detected in vivo. This study aims to develop a new molecular MRI method to assess in vivo ESC viability, proliferation, and teratoma formation. The RG is designed to express 2 antigens (hemagglutinin A and myc) and luciferase on the ESC surface. The two antigens serve as the molecular targets for SPIO-MAb. The human and mouse ESCs were transduced with the RG (ESC-RGs) and transplanted into the peri-infarct area using the murine myocardial injury model. In vivo MRI was performed following serial intravenous administration of SPIO-MAb. Significant hypointense signal was generated from the viable and proliferating ESCs and subsequent teratoma. This novel molecular MRI technique enabled in vivo detection of early ESC-derived teratoma formation in the injured murine myocardium.

αB-crystallin Improves Murine Cardiac Function and Attenuates Apoptosis in Human Endothelial Cells Exposed to Ischemia-reperfusion

The Annals of Thoracic Surgery. Jun, 2011  |  Pubmed ID: 21619989

This study investigates the protective effect of exogenous αB-crystallin (CryAB) on myocardial function after ischemia-reperfusion injury.

Adipose Tissue-derived Stem Cells Display a Proangiogenic Phenotype on 3D Scaffolds

Journal of Biomedical Materials Research. Part A. Sep, 2011  |  Pubmed ID: 21630430

Ischemic heart disease is the leading cause of death worldwide. Recent studies suggest that adipose tissue-derived stem cells (ASCs) can be used as a potential source for cardiovascular tissue engineering due to their ability to differentiate along the cardiovascular lineage and to adopt a proangiogenic phenotype. To understand better ASCs' biology, we used a novel 3D culture device. ASCs' and b.END-3 endothelial cell proliferation, migration, and vessel morphogenesis were significantly enhanced compared to 2D culturing techniques. ASCs were isolated from inguinal fat pads of 6-week-old GFP+/BLI+ mice. Early passage ASCs cells (P3-P4), PKH26-labeled murine b.END-3 cells or a co-culture of ASCs and b.END-3 cells were seeded at a density of 1 × 10(5) on three different surface configurations: (a) a 2D surface of tissue culture plastic, (b) Matrigel, and (c) a highly porous 3D scaffold fabricated from inert polystyrene. VEGF expression, cell proliferation, and tubulization, were assessed using optical microscopy, fluorescence microscopy, 3D confocal microscopy, and SEM imaging (n = 6). Increased VEGF levels were seen in conditioned media harvested from co-cultures of ASCs and b.END-3 on either Matrigel or a 3D matrix. Fluorescence, confocal, SEM, bioluminescence revealed improved cell, proliferation, and tubule formation for cells seeded on the 3D polystyrene matrix. Collectively, these data demonstrate that co-culturing ASCs with endothelial cells in a 3D matrix environment enable us to generate prevascularized tissue-engineered constructs. This can potentially help us to surpass the tissue thickness limitations faced by the tissue engineering community today.

Preclinical Derivation and Imaging of Autologously Transplanted Canine Induced Pluripotent Stem Cells

The Journal of Biological Chemistry. Sep, 2011  |  Pubmed ID: 21719696

Derivation of patient-specific induced pluripotent stem cells (iPSCs) opens a new avenue for future applications of regenerative medicine. However, before iPSCs can be used in a clinical setting, it is critical to validate their in vivo fate following autologous transplantation. Thus far, preclinical studies have been limited to small animals and have yet to be conducted in large animals that are physiologically more similar to humans. In this study, we report the first autologous transplantation of iPSCs in a large animal model through the generation of canine iPSCs (ciPSCs) from the canine adipose stromal cells and canine fibroblasts of adult mongrel dogs. We confirmed pluripotency of ciPSCs using the following techniques: (i) immunostaining and quantitative PCR for the presence of pluripotent and germ layer-specific markers in differentiated ciPSCs; (ii) microarray analysis that demonstrates similar gene expression profiles between ciPSCs and canine embryonic stem cells; (iii) teratoma formation assays; and (iv) karyotyping for genomic stability. Fate of ciPSCs autologously transplanted to the canine heart was tracked in vivo using clinical positron emission tomography, computed tomography, and magnetic resonance imaging. To demonstrate clinical potential of ciPSCs to treat models of injury, we generated endothelial cells (ciPSC-ECs) and used these cells to treat immunodeficient murine models of myocardial infarction and hindlimb ischemia.

Dual Manganese-enhanced and Delayed Gadolinium-enhanced MRI Detects Myocardial Border Zone Injury in a Pig Ischemia-reperfusion Model

Circulation. Cardiovascular Imaging. Sep, 2011  |  Pubmed ID: 21719779

Gadolinium (Gd)-based delayed-enhancement MRI (DEMRI) identifies nonviable myocardium but is nonspecific and may overestimate nonviable territory. Manganese (Mn(2+))-enhanced MRI (MEMRI) denotes specific Mn(2+) uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI identifies viable infarct border zone (BZ) myocardium in vivo.

Immunobiology of Naïve and Genetically Modified HLA-class-I-knockdown Human Embryonic Stem Cells

Journal of Cell Science. Sep, 2011  |  Pubmed ID: 21878509

Human embryonic stem cells (hESCs) can serve as a universal cell source for emerging cell or tissue replacement strategies, but immune rejection of hESC derivatives remains an unsolved problem. Here, we sought to describe the mechanisms of rejection for naïve hESCs and upon HLA class I (HLA I) knockdown (hESC(KD)). hESCs were HLA I-positive but negative for HLA II and co-stimulatory molecules. Transplantation of naïve hESC into immunocompetent Balb/c mice induced substantial T helper cell 1 and 2 (Th1 and Th2) responses with rapid cell death, but hESCs survived in immunodeficient SCID-beige recipients. Histology revealed mainly macrophages and T cells, but only scattered natural killer (NK) cells. A surge of hESC-specific antibodies against hESC class I, but not class II antigens, was observed. Using HLA I RNA interference and intrabody technology, HLA I surface expression of hESC(KD) was 88%-99% reduced. T cell activation after hESC(KD) transplantation into Balb/c was significantly diminished, antibody production was substantially alleviated, the levels of graft-infiltrating immune cells were reduced and the survival of hESC(KD) was prolonged. Because of their very low expression of stimulatory NK ligands, NK-susceptibility of naïve hESCs and hESC(KD) was negligible. Thus, HLA I recognition by T cells seems to be the primary mechanism of hESC recognition, and T cells, macrophages and hESC-specific antibodies participate in hESC killing.

Interleukin-17 Accelerates Allograft Rejection by Suppressing Regulatory T Cell Expansion

Circulation. Sep, 2011  |  Pubmed ID: 21911812

Interleukin-17 (IL-17), which is predominantly produced by T helper 17 cells distinct from T helper 1 or T helper 2 cells, participates in the pathogenesis of infectious, autoimmune, and allergic disorders. However, the precise role in allograft rejection remains uncertain. In the present study, we investigated the role of IL-17 in acute allograft rejection using IL-17-deficient mice.

Novel MicroRNA Prosurvival Cocktail for Improving Engraftment and Function of Cardiac Progenitor Cell Transplantation

Circulation. Sep, 2011  |  Pubmed ID: 21911815

Although stem cell therapy has provided a promising treatment for myocardial infarction, the low survival of the transplanted cells in the infarcted myocardium is possibly a primary reason for failure of long-term improvement. Therefore, the development of novel prosurvival strategies to boost stem cell survival will be of significant benefit to this field.

Human Leukocyte Antigen I Knockdown Human Embryonic Stem Cells Induce Host Ignorance and Achieve Prolonged Xenogeneic Survival

Circulation. Sep, 2011  |  Pubmed ID: 21911816

Although human embryonic stem cells (hESC) have enormous potential for cell replacement therapy of heart failure, immune rejection of hESC derivatives inevitably would occur after transplantation. We therefore aimed to generate a hypoantigeneic hESC line with improved survival characteristics.

Double Knockdown of Prolyl Hydroxylase and Factor-inhibiting Hypoxia-inducible Factor with Nonviral Minicircle Gene Therapy Enhances Stem Cell Mobilization and Angiogenesis After Myocardial Infarction

Circulation. Sep, 2011  |  Pubmed ID: 21911818

Under normoxic conditions, hypoxia-inducible factor (HIF)-1α is rapidly degraded by 2 hydroxylases: prolyl hydroxylase (PHD) and factor-inhibiting HIF-1 (FIH). Because HIF-1α mediates the cardioprotective response to ischemic injury, its upregulation may be an effective therapeutic option for ischemic heart failure.

In Vivo Functional and Transcriptional Profiling of Bone Marrow Stem Cells After Transplantation into Ischemic Myocardium

Arteriosclerosis, Thrombosis, and Vascular Biology. Jan, 2012  |  Pubmed ID: 22034515

Clinical trials of bone marrow-derived stem cell therapy for the heart have yielded variable results. The basic mechanism(s) that underlies their potential efficacy remains unknown. In the present study, we evaluated the survival kinetics, transcriptional response, and functional outcome of intramyocardial bone marrow mononuclear cell (BMMC) transplantation for cardiac repair in a murine myocardial infarction model.

MiR-29b Participates in Early Aneurysm Development in Marfan Syndrome

Circulation Research. Jan, 2012  |  Pubmed ID: 22116819

Rationale: Marfan syndrome (MFS) is a systemic connective tissue disorder notable for the development of aortic root aneurysms and the subsequent life-threatening complications of aortic dissection and rupture. Underlying fibrillin-1 gene mutations cause increased transforming growth factor-β (TGF-β) signaling. Although TGF-β blockade prevents aneurysms in MFS mouse models, the mechanisms through which excessive TGF-β causes aneurysms remain ill-defined. Objective: We investigated the role of microRNA-29b (miR-29b) in aneurysm formation in MFS. Methods and Results: Using quantitative polymerase chain reaction, we discovered that miR-29b, a microRNA regulating apoptosis and extracellular matrix synthesis/deposition genes, is increased in the ascending aorta of Marfan (Fbn1(C1039G/+)) mice. Increased apoptosis, assessed by increased cleaved caspase-3 and caspase-9, enhanced caspase-3 activity, and decreased levels of the antiapoptotic proteins, Mcl-1 and Bcl-2, were found in the Fbn1(C1039G/+) aorta. Histological evidence of decreased and fragmented elastin was observed exclusively in the Fbn1(C1039G/+) ascending aorta in association with repressed elastin mRNA and increased matrix metalloproteinase-2 expression and activity, both targets of miR-29b. Evidence of decreased activation of nuclear factor κB, a repressor of miR-29b, and a factor suppressed by TGF-β, was also observed in Fbn1(C1039G/+) aorta. Furthermore, administration of a nuclear factor κB inhibitor increased miR-29b levels, whereas TGF-β blockade or losartan effectively decreased miR-29b levels in Fbn1(C1039G/+) mice. Finally, miR-29b blockade by locked nucleic acid antisense oligonucleotides prevented early aneurysm development, aortic wall apoptosis, and extracellular matrix deficiencies. Conclusions: We identify increased miR-29b expression as key to the pathogenesis of early aneurysm development in MFS by regulating aortic wall apoptosis and extracellular matrix abnormalities.

Molecular Imaging of Bone Marrow Mononuclear Cell Survival and Homing in Murine Peripheral Artery Disease

JACC. Cardiovascular Imaging. Jan, 2012  |  Pubmed ID: 22239892

This study aims to provide insight into cellular kinetics using molecular imaging after different transplantation methods of bone marrow-derived mononuclear cells (MNCs) in a mouse model of peripheral artery disease (PAD).

Patient-specific Induced Pluripotent Stem Cells As a Model for Familial Dilated Cardiomyopathy

Science Translational Medicine. Apr, 2012  |  Pubmed ID: 22517884

Characterized by ventricular dilatation, systolic dysfunction, and progressive heart failure, dilated cardiomyopathy (DCM) is the most common form of cardiomyopathy in patients. DCM is the most common diagnosis leading to heart transplantation and places a significant burden on healthcare worldwide. The advent of induced pluripotent stem cells (iPSCs) offers an exceptional opportunity for creating disease-specific cellular models, investigating underlying mechanisms, and optimizing therapy. Here, we generated cardiomyocytes from iPSCs derived from patients in a DCM family carrying a point mutation (R173W) in the gene encoding sarcomeric protein cardiac troponin T. Compared to control healthy individuals in the same family cohort, cardiomyocytes derived from iPSCs from DCM patients exhibited altered regulation of calcium ion (Ca(2+)), decreased contractility, and abnormal distribution of sarcomeric α-actinin. When stimulated with a β-adrenergic agonist, DCM iPSC-derived cardiomyocytes showed characteristics of cellular stress such as reduced beating rates, compromised contraction, and a greater number of cells with abnormal sarcomeric α-actinin distribution. Treatment with β-adrenergic blockers or overexpression of sarcoplasmic reticulum Ca(2+) adenosine triphosphatase (Serca2a) improved the function of iPSC-derived cardiomyocytes from DCM patients. Thus, iPSC-derived cardiomyocytes from DCM patients recapitulate to some extent the morphological and functional phenotypes of DCM and may serve as a useful platform for exploring disease mechanisms and for drug screening.