In JoVE (6)

Other Publications (135)

Articles by Gerald Brandacher in JoVE

 JoVE Immunology and Infection

Orthotopic Hind-Limb Transplantation in Rats

1Department of Visceral, Transplant, and Thoracic Surgery, Daniel Swarovski Research Laboratory, Innsbruck Medical University, 2Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Pittsburgh Medical Center

JoVE 2022

 JoVE Medicine

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

1Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, 2Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine

JoVE 50753

 JoVE Medicine

A Novel Microsurgical Model for Heterotopic, En Bloc Chest Wall, Thymus, and Heart Transplantation in Mice

1Johns Hopkins University School of Medicine, 2Burn and Complex Wound Center, 3Section of Plastic and Reconstructive Surgery, University of Chicago Medical Center, 4Division of Plastic, Reconstructive, and Maxillofacial Surgery, R Adams Cowley Shock Trauma Center, 5Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, 6Vascularized Composite Allotransplantation (VCA) Lab, Johns Hopkins University School of Medicine

JoVE 53442

 JoVE Medicine

Orthotopic Hind Limb Transplantation in the Mouse

1Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 2Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, 3Center for Vascularized Composite Allotransplantation, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital and School of Medicine, 4Department of General, Visceral and Transplant Surgery, Charite Berlin

JoVE 53483

 JoVE Immunology and Infection

Murine Full-thickness Skin Transplantation

1Sidney-Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, 2Department of Liver and Transplantation Surgery, Chang-Gung Transplantation Institute, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, 3Vascularized Composite Allotransplantation Laboratory, Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine

JoVE 55105

Other articles by Gerald Brandacher on PubMed

Estradiol Enhances Murine Cardiac Allograft Rejection Under Cyclosporin and Can Be Antagonized by the Antiestrogen Tamoxifen

Transplantation. Aug, 2002  |  Pubmed ID: 12177613

An increased incidence of acute rejection episodes in female heart transplant recipients has been reported in experimental and clinical studies. However, the exact mechanisms of gender-specific differences in alloreactivity are not completely understood.

Gene Expression Profiling of Prolonged Cold Ischemia and Reperfusion in Murine Heart Transplants

Transplantation. Nov, 2002  |  Pubmed ID: 12451246

Heart transplantation causes complex changes in the biological homeostasis of the graft. Current knowledge is restricted to a few genes and regulation of certain factors involved in ischemia-reperfusion (I/R) injury. Efficient strategies to prevent I/R injury, however, require a better understanding of its mechanisms. Using cDNA microarrays, we investigated gene expression profiles of murine cardiac isografts.

Lessons to Be Learned from a Complicated Case of Rhino-cerebral Mucormycosis in a Renal Allograft Recipient

Transplant International : Official Journal of the European Society for Organ Transplantation. Dec, 2003  |  Pubmed ID: 12942168

Fungal infections still represent a serious complication after organ transplantation. Early diagnosis and aggressive treatment are crucial. Because of the many diagnostic problems involved, we present a case of mucormycosis--primarily affecting the paranasal sinuses with later intracranial extension--in a highly immunized recipient of a third renal transplant. Although fungal infection was suspected from various imaging techniques, only the detection of typical fungal hyphae in the infected tissue was diagnostic. Neither the blood tests and cerebrospinal fluid examinations performed nor cultures from maxillary sinus fluid were of any diagnostic help. Surgical debridement from a transnasal as well as an intracranial approach and systemic amphotericin B together with the discontinuation of immunosuppression after removal of the rejected graft were able to save the patient. This case stresses the importance of early diagnosis that can only be made from tissue biopsies and allows appropriate timely treatment.

Mitochondrial Defects and Heterogeneous Cytochrome C Release After Cardiac Cold Ischemia and Reperfusion

American Journal of Physiology. Heart and Circulatory Physiology. May, 2004  |  Pubmed ID: 14693685

Mitochondria play a critical role in myocardial cold ischemia-reperfusion (CIR) and induction of apoptosis. The nature and extent of mitochondrial defects and cytochrome c (Cyt c) release were determined by high-resolution respirometry in permeabilized myocardial fibers. CIR in a rat heart transplant model resulted in variable contractile performance, correlating with the decline of ADP-stimulated respiration. Respiration with succinate or N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (substrates for complexes II and IV) was partially restored by added Cyt c, indicating Cyt c release. In contrast, NADH-linked respiration (glutamate+malate) was not stimulated by Cyt c, owing to a specific defect of complex I. CIR but not cold ischemia alone resulted in the loss of NADH-linked respiratory capacity, uncoupling of oxidative phosphorylation and Cyt c release. Mitochondria depleted of Cyt c by controlled hypoosmotic shock provided a kinetic model of homogeneous Cyt c depletion. Comparison to Cyt c control of respiration in CIR-injured myocardial fibers indicated heterogeneity of Cyt c release. The complex I defect and uncoupling correlated with heterogeneous Cyt c release, the extent of which increased with loss of cardiac performance. These results demonstrate a complex pattern of multiple mitochondrial damage as determinants of CIR injury of the heart.

Steroid- and ATG-resistant Rejection After Double Forearm Transplantation Responds to Campath-1H

American Journal of Transplantation : Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons. Aug, 2004  |  Pubmed ID: 15268743

We herein report on immunological and histological observations in the first bilateral forearm transplant recipient. The last of three rejection episodes occurring on day 95 after transplantation was resistant to steroid and antithymocyte globulin (ATG) treatment. Histology demonstrated lymphocytic infiltrates, apoptotic and necrotic keratinocytes and focal desquamation of the epidermis. Therapy with Campath-1H, however, resulted in complete restitution of normal skin. This is the first report on a successful rescue therapy with Campath-1H in a severe, steroid- and ATG-resistant rejection. Hence, Campath-1H treatment might be a novel and powerful therapeutic option for multiresistant allograft rejection.

Overexpression of Indoleamine 2,3-dioxygenase in Human Inflammatory Bowel Disease

Clinical Immunology (Orlando, Fla.). Oct, 2004  |  Pubmed ID: 15380529

T-cells are causally involved in the pathogenesis of inflammatory bowel disease (IBD). The tryptophan-metabolizing enzyme indoleamine 2,3-dioxygenase (IDO) regulates T-cell proliferation and survival. We show in this report that IDO mRNA is markedly induced in lesional colonic biopsies of IBD patients. IDO is primarily expressed in CD123(+) mononuclear cells infiltrating the submucosal areas of the inflamed lesions. In Crohn's disease (CD), IDO is also strongly expressed in perifollicular regions of lymphoid follicles. Upregulation of IDO is of functional significance, as we detected an increase of kynurenine and of the kynurenine/tryptophan ratio in supernatants from colonic explant cultures (CECs) of CD patients. Immunohistochemistry of colonic biopsies taken from CD patients prior and after treatment with the TNF-blocking antibody Infliximab revealed reduced IDO expression in patients with good clinical response to Infliximab. In summary, high local expression of IDO may represent an anti-inflammatory mechanism tempting to counterbalance the tissue-damaging effects of activated T-cells infiltrating the colonic mucosa in IBD.

Complete Hepatic Ischemia Due to Torsion of a Large Accessory Liver Lobe: First Case to Require Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. Apr, 2005  |  Pubmed ID: 15773969

Anatomical abnormalities of the liver are extremely rare. Although the majority of cases with an accessory liver are not detected, it can give rise to various clinical symptoms like recurrent abdominal pain and impaired liver function. Here we present the first case of orthotopic liver transplantation in a patient with hepatic ischemia caused by complete vascular occlusion due to a twisted accessory liver lobe. Although rare, an accessory liver lobe may cause serious and life-threatening problems and should therefore be kept in mind in patients presenting with acute abdominal pain.

14-3-3sigma Expression is an Independent Prognostic Parameter for Poor Survival in Colorectal Carcinoma Patients

Clinical Cancer Research : an Official Journal of the American Association for Cancer Research. May, 2005  |  Pubmed ID: 15867223

14-3-3sigma is an intracellular, dimeric, phosphoserine binding protein that is expressed in epithelial cells and involved in cancer development. In this study, we examined the expression of 14-3-3sigma and evaluated its clinical significance in colorectal carcinoma.

Tetrahydro-4-aminobiopterin Attenuates Dendritic Cell-induced T Cell Priming Independently from Inducible Nitric Oxide Synthase

Journal of Immunology (Baltimore, Md. : 1950). Jun, 2005  |  Pubmed ID: 15944258

Formation of NO by NO synthases (NOSs) strictly depends on tetrahydrobiopterin. Its structural analog, tetrahydro-4-aminobiopterin, is an inhibitor of all NOS isoenzymes, which prolongs allograft survival in acute murine cardiac rejection and prevents septic shock in the rat. In this study, we show that murine bone marrow-derived dendritic cells treated with tetrahydro-4-aminobiopterin had a reduced capacity to prime alloreactive murine T cells in oxidative mitogenesis. Checking for a possible influence on LPS-induced dendritic cell maturation, we found that tetrahydro-4-aminobiopterin down-regulated MHC class II expression and counteracted LPS-induced down-regulation of ICOS ligand, while expression of CD40, CD86, CD80, B7-H1, and B7-DC remained unchanged. Tetrahydro-4-aminobiopterin also reduced activation of CD4(+) T cells isolated from mice overexpressing an OVA-specific TCR by OVA-loaded murine bone marrow-derived dendritic cells, thus indicating that its effect on MHC class II expression is involved in attenuating T cell activation. In line with affecting dendritic cell function and T cell activation, tetrahydro-4-aminobiopterin impaired production of proinflammatory cytokines and the Th1 response. With regard to cell survival, tetrahydro-4-aminobiopterin induced efficient apoptosis of murine T cells but not of murine dendritic cells. Experiments with cells from inducible NOS (iNOS) knockout mice and with N(6)-(1-iminoethyl)-L-lysine, a specific inhibitor of iNOS, ruled out participation of iNOS in any of the observed effects. These findings characterize attenuation of T cell stimulatory capacity of murine bone marrow-derived dendritic cells as an immunosuppressive mechanism of tetrahydro-4-aminobiopterin that is not related to its iNOS-inhibiting properties.

Cytomegalovirus-related Complications in Human Hand Transplantation

Transplantation. Aug, 2005  |  Pubmed ID: 16123716

Up to date, 24 hands/thumbs have been transplanted in 18 patients. We herein report on cytomegalovirus (CMV) infection, disease, and the adopted treatment.

Prognostic Value of Indoleamine 2,3-dioxygenase Expression in Colorectal Cancer: Effect on Tumor-infiltrating T Cells

Clinical Cancer Research : an Official Journal of the American Association for Cancer Research. Feb, 2006  |  Pubmed ID: 16489067

The pathologic interactions between tumor and host immune cells within the tumor microenvironment create an immunosuppressive network that promotes tumor growth and protects the tumor from immune attack. In this study, we examined the contribution of the immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) on this phenomenon.

Tetrahydrobiopterin Compounds Prolong Allograft Survival Independently of Their Effect on Nitric Oxide Synthase Activity

Transplantation. Feb, 2006  |  Pubmed ID: 16495807

In previous work, the four-amino analogue of tetrahydrobiopterin, a novel, selective inhibitor of inducible nitric oxide synthase, has been shown to prolong survival of murine cardiac allografts.

Bariatric Surgery Cannot Prevent Tryptophan Depletion Due to Chronic Immune Activation in Morbidly Obese Patients

Obesity Surgery. May, 2006  |  Pubmed ID: 16687019

Increased activity of the immuno-modulatory enzyme indoleamine-2,3-dioxygenase (IDO) during immune activation, results in tryptophan depletion. Tryptophan metabolic changes reduce serotonin production and cause mood disturbances, depression, and impaired satiety, ultimately leading to increased food intake and obesity. Bariatric surgery significantly diminishes immune mediators by substantial weight reduction. We examined IDO-mediated tryptophan-catabolism in morbidly obese patients compared to lean individuals.

Antitumoral Activity of Interferon-gamma Involved in Impaired Immune Function in Cancer Patients

Current Drug Metabolism. Aug, 2006  |  Pubmed ID: 16918315

Insufficient immunosurveillance is an important aspect in early tumorigenesis and in the pathogenesis of malignant disease. In the later course of cancer, the development of immunodeficiency is considered the major reason for disease progression and death. Within the anti-tumoral host defense reaction, Th1-type cytokine interferon-gamma (IFN-gamma) is of particular relevance. IFN-gamma stimulates several anti-proliferative and thus tumoricidal biochemical pathways in macrophages and other cells and also in tumor cell lines. These include inducible nitric oxide synthase, indoleamine (2, 3)-dioxygenase, an enzyme degrading the essential amino acid tryptophan, and the production of reactive oxygen species and neopterin in human macrophages and dendritic cells. Although the anti-proliferative strategy of the immune system aims to inhibit the growth of malignant cells, it can also affect T-cell response and thus contribute to the development of immunodeficiency. Accelerated degradation of tryptophan and increased production of neopterin were found to parallel the course of malignant diseases. Moreover, a higher degree of these metabolic changes characterizes poor prognosis and is associated with the development of anemia, weight loss and depressive mood in patients. Available data suggest that immunodeficiency in cancer patients may develop as a long-term side-effect of the antiproliferative and pro-apoptotic mechanisms elicited within Th1-type immune response, and enhanced production of pro-inflammatory cytokine IFN-gamma seems to be critically involved.

Hemolytic Uremic Syndrome Following Campath-1H Induction

Transplant International : Official Journal of the European Society for Organ Transplantation. Apr, 2007  |  Pubmed ID: 17326780

Hemolytic uremic syndrome (HUS) is a rare complication following solid organ transplantation. We report on a patient who underwent renal transplantation using Campath-1H induction and tacrolimus maintenance therapy who developed HUS, which was managed by plasma exchange and switch to Rapamycin. However, graft function could not be restored.

CTLA4Ig Promotes the Induction of Hematopoietic Chimerism and Tolerance Independently of Indoleamine-2,3-dioxygenase

Transplantation. Mar, 2007  |  Pubmed ID: 17353791

Bone marrow transplantation (BMT) under costimulation blockade induces mixed chimerism and tolerance in rodent models. Recent data, predominantly from in vitro studies, suggest that in addition to blocking the CD28 costimulation pathway CTLA4Ig also acts through upregulating the tryptophan-catabolizing enzyme indoleamine-2,3-dioxygenase (IDO). Here we demonstrate that even though CTLA4Ig is critically required for the induction of chimerism and tolerance in a murine model of nonmyeloablative BMT, IDO activity is not. No significant differences were detectable in the kynurenine to tryptophan ratios (indicative of IDO activity) in sera of BMT recipients treated with CTLA4Ig (tolerant group) versus BMT recipients treated without CTLA4Ig (nontolerant group) versus naïve controls. In vivo inhibition of IDO immediately after BMT with CTLA4Ig or several months thereafter did not block achievement of chimerism and tolerance. Thus, IDO does not play a critical role in the induction or maintenance of chimerism and tolerance in a CTLA4Ig-based BMT model.

Laparoscopically Implanted Gastric Pacemaker After Kidney-pancreas Transplantation: Treatment of Morbid Obesity and Diabetic Gastroparesis

Obesity Surgery. Jan, 2007  |  Pubmed ID: 17355776

Combined kidney-pancreas transplantation is the treatment of choice for end-stage diabetic nephropathy. Weight gain post-transplant increases the risk for post-transplant complications and death due to cardiovascular events. Gastric pacemakers have been used for therapy of diabetic gastropathy and for the treatment of moderate morbid obesity. We report a patient who experienced significant weight gain following successful kidney-pancreas transplantation and was thereafter successfully treated for diabetic gastroparesis and morbid obesity by use of a laparoscopically implanted gastric pacemaker.

Implications of IFN-gamma-mediated Tryptophan Catabolism on Solid Organ Transplantation

Current Drug Metabolism. Apr, 2007  |  Pubmed ID: 17430115

The Th1-type cytokine interferon-gamma (IFN-gamma) is known as one of the most versatile players of the immune system. In transplantation immunology IFN-gamma has been shown to have contradictory effects on allograft survival via effects on both, the immune system and on the graft itself. The immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO), widely distributed in mammals, is induced preferentially by IFN-gamma. IDO degrades the essential amino acid tryptophan to form N-formyl kynurenine which is subsequently converted to niacin. Recently, it has been proposed that IFN-gamma-mediated activation of IDO is critically involved in the regulation of immune responses, to establish immune-tolerance in pregnant mice upon their fetuses, or to induce T-cell unresponsiveness. Proliferation of alloreactive T-cells is thereby arrested via local tryptophan deprivation and the accumulation of toxic tryptophan catabolites. Despite growing recognition of the molecular T-cell regulatory mechanisms, the physiologic role of IDO in solid organ transplantation, however, remains unclear. Available experimental data indicate that IDO is involved in the mechanism of spontaneous donor-specific tolerance of liver grafts, and that genetic manipulation by introduction of the IDO gene into allografts is associated with prolonged survival. Furthermore, antigen-presenting cells, such as dendritic cells, can increase their expression of IDO, thus regulating immune responses. Based on these findings, the concept that cells expressing IDO can inhibit T-cell responses and hence induce tolerance has emerged as a new paradigm in immunology. Here we review the current literature on IDO in the context of transplantation and outline its potential implication as a target for tolerance induction.

A Novel Technique for Heterotopic Vascularized Pancreas Transplantation in Mice to Assess Ischemia Reperfusion Injury and Graft Pancreatitis

Surgery. May, 2007  |  Pubmed ID: 17462470

Although various suture techniques for murine pancreas transplantation have been described, severe limitations have limited their widespread use. We therefore designed a surgical model for cervical heterotopic pancreas transplantation using a cuff technique.

Induction of Indoleamine 2,3-dioxygenase in Vascular Smooth Muscle Cells by Interferon-gamma Contributes to Medial Immunoprivilege

Journal of Immunology (Baltimore, Md. : 1950). Oct, 2007  |  Pubmed ID: 17911610

Atherosclerosis and graft arteriosclerosis are characterized by leukocytic infiltration of the vessel wall that spares the media. The mechanism(s) for medial immunoprivilege is unknown. In a chimeric humanized mouse model of allograft rejection, medial immunoprivilege was associated with expression of IDO by vascular smooth muscle cells (VSMCs) of rejecting human coronary artery grafts. Inhibition of IDO by 1-methyl-tryptophan (1-MT) increased medial infiltration by allogeneic T cells and increased VSMC loss. IFN-gamma-induced IDO expression and activity in cultured human VSMCs was considerably greater than in endothelial cells (ECs) or T cells. IFN-gamma-treated VSMCs, but not untreated VSMCs nor ECs with or without IFN-gamma pretreatment, inhibited memory Th cell alloresponses across a semipermeable membrane in vitro. This effect was reversed by 1-MT treatment or tryptophan supplementation and replicated by the absence of tryptophan, but not by addition of tryptophan metabolites. However, IFN-gamma-treated VSMCs did not activate allogeneic memory Th cells, even after addition of 1-MT or tryptophan. Our work extends the concept of medial immunoprivilege to include immune regulation, establishes the compartmentalization of immune responses within the vessel wall due to distinct microenvironments, and demonstrates a duality of stimulatory EC signals versus inhibitory VSMC signals to artery-infiltrating T cells that may contribute to the chronicity of arteriosclerotic diseases.

Mitochondrial Ischemia-reperfusion Injury of the Transplanted Rat Heart: Improved Protection by Preservation Versus Cardioplegic Solutions

Shock (Augusta, Ga.). Oct, 2008  |  Pubmed ID: 18317412

Cold ischemia time and preservation of organs are limited by I/R injury leading to primary nonfunction of the graft. In a rat heart transplant model, we compared cardioplegic St Thomas (ST) to histidine-tryptophan-ketoglutarate (HTK) and University of Wisconsin preservation solutions in terms of contractile function, and mitochondrial respiratory and enzymatic defects after prolonged cold ischemia and reperfusion. Contractile function was scored after transplantation and 24 h of reperfusion. Mitochondrial function was investigated by high-resolution respirometry of permeabilized myocardial fibers. Graft performance in terms of contractile function declined with the duration of cold storage. Recovery was significantly improved after 10 h of cold storage in HTK compared with ST (cardiac scores, 3.3+/-0.5 and 1.8+/-0.8, respectively). Tissue lactate dehydrogenase was better preserved in HTK than ST. Increase of tissue water content (edema) was less pronounced in HTK than ST (3.33+/-0.14 and 3.73+/-0.21 mg/mg dry weight, respectively). Similar cardiac scores (2.6+/-0.9 and 2.9+/-1.2, respectively) and mitochondrial respiratory parameters were obtained after preservation in HTK and University of Wisconsin. Decline in contractile function of individual grafts correlated well with loss of mitochondrial respiratory capacity, whereas citrate synthase activity remained largely preserved, indicating specific damage of respiratory complexes. Our data provide evidence for the superiority of preservation solutions versus a cardioplegic solution for prolonged cold storage of the heart. The correlation of graft performance and mitochondrial function indicates the potential of high-resolution respirometry for quantitative assessment of myocardial injury upon cold I/R, providing a basis for diagnostic approaches and evaluation of improved preservation solutions for heart transplantation.

Potential Applications of Global Protein Expression Analysis (proteomics) in Morbid Obesity and Bariatric Surgery

Obesity Surgery. Jul, 2008  |  Pubmed ID: 18330661

Global protein expression analysis, known as proteomics, has emerged as a novel scientific technology currently successfully applied to several fields of medicine including cancer and transplantation. Thereby, a thorough exploration of the pathogenic mechanisms and a better understanding of the pathophysiology of diseases as well as identification of diagnostic biomarkers have been achieved. In this paper, we outline the basic principles and potential applications of this promising tool in bariatric surgery where proteomics might hold great potential for new insights into diagnostic and therapeutic decision making based on improved knowledge of metabolic regulations pre- and postsurgical interventions in morbidly obese patients.

Clinical Relevance of Indoleamine 2,3-dioxygenase for Alloimmunity and Transplantation

Current Opinion in Organ Transplantation. Feb, 2008  |  Pubmed ID: 18660700

The immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) is activated by interferon-gamma and via tryptophan depletion and the production of proapoptotic downstream metabolites IDO suppresses adaptive T-cell-mediated immunity in inflammation, host immune defence and maternal tolerance. In addition, IDO-mediated tryptophan catabolism occurring in dendritic cells is an emerging potent mechanism of peripheral tolerance.

Intracellular Signaling Pathways Control Mitochondrial Events Associated with the Development of Ischemia/ Reperfusion-associated Damage

Transplant International : Official Journal of the European Society for Organ Transplantation. Sep, 2009  |  Pubmed ID: 19413579

Ischemia (I) and reperfusion (R) trigger a series of events, which culminate in severe injury to the transplanted organ. Cell death resulting from the formation of mitochondrial reactive oxygen species (ROS) coupled with the perturbation of mitochondrial Ca2+ homeostasis is central to the development of IR-associated tissue damage. We and others have shown recently that intracellular signaling pathways critically control these mitochondrial changes, making them potential targets for therapeutic intervention. Using a heterotopic murine heart transplant model as well as primary and immortalized cardiomyocyte cells we established the activity patterns of mitogen-activated protein kinases (MAPKs) ERK, JNK, and p38 during IR, and probed into their role in the perturbation of mitochondrial ROS and Ca2+ homeostasis, which are necessary for cardiomyocyte death. Our results showed a strong activation of all three MAPKs as well as a rise in mitochondrial ROS and Ca2+ during early reoxygenation. Inhibiting p38 kinase most efficiently prevented ROS production, Ca2+ overload and cell death, suggesting that targeting this signaling molecule may provide a possible strategy to limit the effects of IR.

Proteomic Profiling of Acute Cardiac Allograft Rejection

Transplantation. Aug, 2009  |  Pubmed ID: 19696639

Proteome analysis has emerged as a valuable tool for the study of large-scale protein expression profiles. Here, we applied this novel technology to identify specific biomarkers for acute cardiac allograft rejection.

Neopterin, a Prognostic Marker in Human Malignancies

Cancer Letters. Jan, 2010  |  Pubmed ID: 19500901

Increased neopterin concentrations are established in patients with an activated cellular (= Th1-type) immune response which includes allograft rejection, viral infection and autoimmune disorders as well as various malignant tumors. In patients with several types of cancer, neopterin concentrations in body fluids like urine, serum/plasma or ascites parallel the course of the disease, and a higher neopterin concentration in patients is an independent predictor of a shorter survival period. Neopterin is released in large amounts from human monocyte-derived macrophages and dendritic cells preferentially following stimulation with the pro-inflammatory cytokine interferon-gamma, thus reflecting the immune activation status. Therefore, not only as a laboratory diagnostic tool, the measurement of neopterin concentrations allows studying the immunological network and its interaction with the pathogenesis of tumor development. It contributes to a better understanding how immune activation is involved in the development of tumor-induced immune escape and tumor antigen specific tolerance.

Are B Cells Agreeable to Veto?

Transplantation. Mar, 2010  |  Pubmed ID: 20048694

Tetrahydrobiopterin Protects the Kidney from Ischemia-reperfusion Injury

Kidney International. Apr, 2010  |  Pubmed ID: 20164829

Tetrahydrobiopterin (BH4) is an essential cofactor for the nitric oxide (NO) synthases and represents a critical determinant of NO production. BH4 depletion during ischemia leads to the uncoupling of the synthases, thus contributing to reperfusion injury due to increased superoxide formation. To examine whether BH4 supplementation attenuates ischemia-reperfusion injury, we clamped the left renal arteries of male Lewis rats immediately following right-side nephrectomy. BH4 tissue levels significantly decreased after 45 min of warm ischemia compared with levels in non-ischemic controls. Histopathology demonstrated significant tubular damage and increased peroxynitrite formation. Intravital fluorescent microscopy found perfusion deficits in the microvasculature and leakage of the capillary mesh. Supplemental BH4 treatment before ischemia significantly reduced ischemia-induced renal dysfunction, and decreased tubular histologic injury scores and peroxynitrite generation. BH4 also significantly improved microcirculatory parameters such as functional capillary density and diameter. These protective effects of BH4 on microvasculature were significantly correlated with its ability to abolish peroxynitrite formation. We suggest that BH4 significantly protects against acute renal failure following ischemia reperfusion. Whether BH4 has a therapeutic potential will require more direct testing in humans.

Composite Tissue Allotransplantation: Hand Transplantation and Beyond

The Journal of the American Academy of Orthopaedic Surgeons. Mar, 2010  |  Pubmed ID: 20190102

Recent advances in transplant immunology are shifting the focus from immunosuppression to immunoregulation, making composite tissue allotransplantation with novel and less potent immunosuppressive regimens a possibility. Hand transplantation has been the most frequently performed human composite tissue allotransplantation, with more than 50 upper extremity-based transplants done worldwide. Further research is needed regarding immunomodulating protocols, and careful oversight and individualized screening procedures will be required as patients seeking improved quality of life through human composite tissue allotransplantation come to accept a certain level of risk in these experimental procedures. Still, composite tissue allotransplantation offers to advance transplant medicine and reconstructive surgery.

T Regulatory Cells and Transplantation Tolerance

Transplantation Reviews (Orlando, Fla.). Jul, 2010  |  Pubmed ID: 20541385

Despite the development of successful immunosuppression protocols and tremendous improvement in short-term graft survival rates, the problem of chronic graft loss remains the bane of clinical transplantation. The induction and maintenance of transplantation tolerance is the "Holy Grail" of transplantation. The recent identification and characterization of regulatory T cells has opened up exciting opportunities for tolerance induction, immunotherapy, and immunomodulation in transplantation. This review focuses on current understanding of regulatory T cells and their role in transplantation tolerance.

Cold Ischemia Contributes to the Development of Chronic Rejection and Mitochondrial Injury After Cardiac Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. Dec, 2010  |  Pubmed ID: 20561305

Chronic rejection (CR) remains an unsolved hurdle for long-term heart transplant survival. The effect of cold ischemia (CI) on progression of CR and the mechanisms resulting in functional deficit were investigated by studying gene expression, mitochondrial function, and enzymatic activity. Allogeneic (Lew→F344) and syngeneic (Lew→Lew) heart transplantations were performed with or without 10 h of CI. After evaluation of myocardial contraction, hearts were excised at 2, 10, 40, and 60 days for investigation of vasculopathy, gene expression, enzymatic activities, and mitochondrial respiration. Gene expression studies identified a gene cluster coding for subunits of the mitochondrial electron transport chain regulated in response to CI and CR. Myocardial performance, mitochondrial function, and mitochondrial marker enzyme activities declined in all allografts with time after transplantation. These declines were more rapid and severe in CI allografts (CR-CI) and correlated well with progression of vasculopathy and fibrosis. Mitochondria related gene expression and mitochondrial function are substantially compromised with the progression of CR and show that CI impacts on progression, gene profile, and mitochondrial function of CR. Monitoring mitochondrial function and enzyme activity might allow for earlier detection of CR and cardiac allograft dysfunction.

Cytomegalovirus Mismatch As Major Risk Factor for Delayed Graft Function After Pancreas Transplantation

Transplantation. Sep, 2010  |  Pubmed ID: 20724959

Risk factors for delayed graft function (DGF) in pancreas transplantation (PTx) and its implications on graft survival are poorly defined.

A Rapid Vascular Anastomosis Technique for Hind-limb Transplantation in Rats

Plastic and Reconstructive Surgery. Sep, 2010  |  Pubmed ID: 20811220

Mouse Hind Limb Transplantation: a New Composite Tissue Allotransplantation Model Using Nonsuture Supermicrosurgery

Transplantation. Dec, 2010  |  Pubmed ID: 21076369

The development of microsurgical techniques has facilitated the establishment of vascularized composite tissue transplant models in small mammals. Because the mouse would be the ideal model to study various composite tissue allotransplantation (CTA)-related problems, we designed two new surgical techniques for orthotopic (ORT) and heterotopic (HET) hind limb transplantation.

Alemtuzumab in Solid Organ Transplantation and in Composite Tissue Allotransplantation

Immunotherapy. Nov, 2010  |  Pubmed ID: 21091110

Alemtuzumab (Campath®, Genzyme Corporation, MA, USA) is a potent monoclonal antilymphocyte, anti-CD52 antibody. Since the 1980s, alemtuzumab has been used extensively in organ transplantation as an induction agent - also with the aim of avoiding or reducing maintenance immunosuppression. We herein review the literature on alemtuzumab in solid organ and composite tissue allotransplantation with an emphasis on clinical and mechanistic aspects of alemtuzumab. In summary, the use of alemtuzumab in solid organ and composite tissue allotransplantation shows excellent early results and holds potential for wider use in conjunction with immunosuppression minimization protocols.

Hand Allotransplantation

Seminars in Plastic Surgery. Feb, 2010  |  Pubmed ID: 21286301

In the past decade, more than 100 different composite tissue allotransplantation (CTA) procedures have been performed around the world including more than 50 hand and 8 facial transplants with encouraging graft survival and excellent functional outcomes. Broader clinical application of CTA, however, continues to be hampered by requirement for long-term, high-dose, multidrug maintenance immunosuppression to prevent graft rejection mediated particularly by composite tissue allograft's highly immunogenic skin component. Medication toxicity could result in severe adverse events including metabolic and infectious complications or malignancy. Notably, unlike in solid organs, clinical success is dictated not only by graft acceptance and survival but also by nerve regeneration, which determines ultimate functional outcomes. Novel strategies such as cellular and biologic therapies that integrate the concepts of immune regulation with those of nerve regeneration have shown promising results in small and large animal models. Clinical translation of these insights to reconstructive transplantation and CTA could further minimize the need of immunosuppression and optimize functional outcomes. This will enable wider application of such treatment options for patients in need of complex reconstructive surgery for congenital deformities or devastating injuries that are not amenable to standard methods of repair.

IDO-Mediated Tryptophan Degradation in the Pathogenesis of Malignant Tumor Disease

International Journal of Tryptophan Research : IJTR. 2010  |  Pubmed ID: 22084593

Immune escape is a fundamental trait of cancer in which the Th1-type cytokine interferon- γ (IFN-γ) seems to play a key role. Among other tumoricidal biochemical pathways, IFN-γ induces the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) in a variety of cells including macrophages, dendritic cells (DCs) and tumor cells. IDO activity has been shown to reflect the extent and the course in a plethora of malignancies including prostate, colorectal, pancreatic, cervical, endometrial, gastric, lung, bladder, ovarian, esophageal and renal cell carcinomas, glioblastomas, mesotheliomas, and melanomas. Furthermore IDO activity during malignant tumor diseases seems to be part of the tumoricidal immune defense strategy, which in the long run is detrimental to the host, when tryptophan deprivation and production of pro-apoptotic tryptophan catabolites counteract T-cell responsiveness.

Expression and Prognostic Impact of Indoleamine 2,3-dioxygenase in Oral Squamous Cell Carcinomas

Oral Oncology. May, 2011  |  Pubmed ID: 21440489

Indoleamine 2,3 dioxygenase (IDO) is a negative immune regulator and was found to be a prognostic marker in several tumor entities. In this study, we analysed IDO expression in oral squamous cell carcinoma (OSCC) regarding patient's prognosis. Additionally, expression of IDO like-1 gene (INDOL-1) was analysed. Tumor tissue from 88 patients with OSCC was analysed by immunohistochemistry for IDO expression. The influence of IDO expression on survival was studied by multivariate Cox regression, adjusting for established clinical prognostic parameters. Real time PCR of tumor samples was performed in a subgroup of patients to analyse mRNA expression of IDO and INDOL-1. IDO high-expression was observed in 44.2% of OSCC patients. No significant correlation was found between IDO expression and clinical stage, sex, age, tumor site, tumor size, metastasis or tumor grade. The median overall survival time was 3.1 years for patients with IDO low tumors, compared to 1.36 years for IDO high tumors (P=.028). Subset analysis of patients receiving adjuvant radio-chemotherapy showed a significant difference (P=.0046) in overall survival between IDO low tumors (3.35 years) and IDO high tumors (1.26 years). In contrast, the impact of IDO expression on survival time in patients without adjuvant therapy was not significant (P=.574). Interestingly, INDOL-1 was not expressed in OSCC. IDO high expression represents a significant negative prognostic factor in patients with OSCC, especially in those patients undergoing adjuvant radiochemotherapy. Our data support the suggestion, co-administration of small-molecule IDO inhibitors could represent a promising new strategy to increase the anti-tumor activity of radio-chemotherapy in patients with IDO positive OSCC.

Achievements and Challenges in Composite Tissue Allotransplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. Aug, 2011  |  Pubmed ID: 21554424

Overall, more than 60 hand/forearm/arm transplantations and 16 face transplantations have been performed in the past 12 years. In the European experience summarized here, three grafts have been lost in response to a vascular thrombosis (n = 1), rejection and incompliance with immunosuppression (n = 1) and death (n = 1). The overall functional and esthetic outcome is very satisfactory, but serious side effects and complications related to immunosuppression are challenges hindering progress in this field. The high levels of immunosuppression, skin rejection, nerve regeneration, donor legislation and the acceptance level need to be addressed to promote growth of this promising new field in transplantation and reconstructive surgery.

Single-center Experience with Third and Fourth Kidney Transplants

Transplant International : Official Journal of the European Society for Organ Transplantation. Aug, 2011  |  Pubmed ID: 21569127

Kidney retransplantation is often associated with a higher immunological risk than is primary renal transplantation. Faced with increasing organ shortage and growing waiting lists, results of kidney retransplantation are of particular interest. Fifty-six third and fourth kidney transplants were analyzed retrospectively. Parameters included patient and donor demographics, operative details, incidence of surgical, immunological and infectious complications and patient and graft survival. Patients receiving third kidney grafts had 1- and 5-year patient/graft survival rates of 97.4%/72.9% and 88.9%/53.6%, respectively. Episodes of acute rejection and delayed graft function were observed in 44% and 49% of these patients. Fourth kidney transplantation was associated with 1- and 2-year patient/graft survival rates of 84.8%/68.5% and 63.6%/47%, respectively. Acute rejection and delayed graft function occurred in 33% and in 60% of cases. Acceptable patient and graft survival may be achieved after third and fourth kidney transplantation. Graft losses in this sensitized population are mainly because of rejection. Profound immunosuppression may lead to major infectious problems.

Proteomics--a Blessing or a Curse? Application of Proteomics Technology to Transplant Medicine

Transplantation. Sep, 2011  |  Pubmed ID: 21716169

Proteomics has emerged as a powerful tool in clinical biomarker research. In the field of transplantation, proteomics aims not only at developing noninvasive tools for immune monitoring and identifying biomarkers of allograft rejection but also to gain mechanistic insights into the pathophysiology of an alloimmune response and hence defining new therapeutic targets. A basic knowledge of proteomic technology is a prerequisite to appreciate the complex data generated and required for critical evaluation/interpretation of proteomic-driven studies. This review provides an overview of proteomic approaches and its underlying concepts and discusses the advantages, clinical implications, challenges, and limitations of this exciting modality in transplantation.

Influence of Immunosuppressive Agents on Tryptophan Degradation and Neopterin Production in Human Peripheral Blood Mononuclear Cells

Transplant Immunology. Sep, 2011  |  Pubmed ID: 21742032

The anti-proliferative and immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) degrades the essential amino acid tryptophan via the kynurenine pathway. IDO is stimulated during cellular immune responses preferentially by Th1-type cytokine interferon-γ (IFN-γ). IDO activity is estimated by calculating the kynurenine to tryptophan ratio (Kyn/Trp). In human monocyte-derived macrophages and dendritic cells, GTP-cyclohydrolase I is induced in parallel to IDO and produces neopterin. This study investigated the effects of common immunosuppressants on freshly isolated human peripheral blood mononuclear cells (PBMC) in vitro. PBMC were incubated with compounds for 30 min and then either left unstimulated or stimulated with mitogen phytohaemagglutinin (PHA). Concentrations of tryptophan, kynurenine and neopterin were measured in supernatants after 48 h. Kyn/Trp, neopterin and IFN-γ concentrations were significantly higher in PHA-stimulated vs. unstimulated PBMC. Tacrolimus (FK506), cyclosporine A (CsA), sirolimus and methylprednisolone dose-dependently inhibited tryptophan degradation and neopterin production. FK506, CsA and sirolimus showed significant inhibition at concentrations as low as 0.1 μg/ml, whereas prednisolone and methylprednisolone required higher doses to suppress tryptophan degradation. Mycophenolate-mofetil suppressed neopterin formation more efficiently than Kyn/Trp. All tested drugs also strongly decreased mitogen-induced IFN-γ concentrations. Overall the investigated immunosuppressants are effective to inhibit IDO activity and neopterin production in a similar and dose-dependent manner, however with some differences in IC50s when comparing individual compounds. The corresponding changes of IFN-γ concentrations are in line with its role as a trigger of both biochemical changes.

The Effect of Chondroitinase on Nerve Regeneration Following Composite Tissue Allotransplantation

The Journal of Hand Surgery. Sep, 2011  |  Pubmed ID: 21788107

To improve the degree of functional return and sensibility provided by composite tissue allotransplantation, enhanced nerve regeneration is essential. Chondroitin sulfate proteoglycans are found in the extracellular matrix of nerves and inhibit regenerating axons after injury. Treatment with chondroitinase to remove chondroitin sulfate proteoglycans has been shown to improve nerve regeneration in isolated nerve graft and transection-and-repair models. This study assesses the efficacy of chondroitinase as a neurotherapeutic agent in the setting of composite tissue allotransplantation.

Concomitant Face and Hand Transplantation: Perfect Solution or Perfect Storm?

Annals of Plastic Surgery. Sep, 2011  |  Pubmed ID: 21836456

Face and hand composite tissue allotransplantations have evolved into a promising subset of reconstructive transplant surgery due to recent advances in immunotherapy. Concomitant composite tissue allotransplantation, which involves a variable combination of facial (myocutaneous versus osteomyocutaneous) and upper extremity (ie, various levels) composite subtypes, has been performed infrequently at this time. In this review, we will describe many reasons as to why this field remains unexplored. Undoubtedly, future investigation is warranted to investigate the potential advantages and disadvantages of using this approach versus a staged manner for alloreconstruction and to identify the complexities of cortical reorganization and rehabilitation in this setting.

Clinical Implementation of a Procedure to Prepare Bone Marrow Cells from Cadaveric Vertebral Bodies

Regenerative Medicine. Nov, 2011  |  Pubmed ID: 22050522

AIMS: Vertebral bone marrow is a rich and easily accessible source of hematopoietic and mesenchymal stem cells that has been used to promote chimerism and transplantation tolerance in connection with cadaveric organ transplantation. The purpose of this study is to provide a detailed account of the procedure used to prepare the first five vertebral bone marrow products for infusion in conjunction with the first hand/hand-forelimb transplants performed at the University of Pittsburgh (PA, USA). MATERIALS & METHODS: The cell separation and release testing were performed at the University of Pittsburgh Cancer Institute's Hematopoietic Stem Cell Laboratory, a Good Manufacturing Practice-compliant facility accredited for clinical cell processing by the Foundation for Accreditation of Cellular Therapy (FACT) and for clinical flow cytometry by the College of American Pathologists (CAP).

World Experience After More Than a Decade of Clinical Hand Transplantation: Update on the Innsbruck Program

Hand Clinics. Nov, 2011  |  Pubmed ID: 22051384

Patients who have lost a hand or upper extremity face many challenges in everyday life. For some patients, reconstructive hand transplantation represents a reasonable option for anatomic reconstruction, restoring prehensile function with sensation and allowing them to regain daily living independence. The first clinical case of bilateral hand transplantation at University Hospital Innsbruck was realized on March 17th, 2000. A decade later, a total of 7 hands and forearms were transplanted in 4 patients. This article review the clinical courses of 3 bilateral hand transplant recipients and highlights psychological aspects on reconstructive hand transplantation with special regard to unilateral/bilateral transplantation.

Functional Outcome After Hand and Forearm Transplantation: What Can Be Achieved?

Hand Clinics. Nov, 2011  |  Pubmed ID: 22051387

The first successful hand transplant in the modern era of reconstructive transplantation was performed in 1998. Since then, more than 65 hand and upper limb transplantations have been performed around the globe, with encouraging results. The main goal of all upper limb transplantations is to enhance the patient's quality of life. The transplant must be successfully integrated into the patient's body and self-image and the recipient should be satisfied with the recovery of sensitivity and muscle function of the new limb. To achieve these goals, a proper and thorough design of the rehabilitation regimen is of critical importance.

Favoring the Risk-benefit Balance for Upper Extremity Transplantation--the Pittsburgh Protocol

Hand Clinics. Nov, 2011  |  Pubmed ID: 22051391

Upper extremity transplantation is an innovative reconstructive strategy with potential of immediate clinical application and the most near-term pay-off for select amputees, allowing reintegration into employment and society. Routine applicability and widespread impact of such strategies for the upper extremity amputees with devastating limb loss could be enabled by implementation of cellular therapies that integrate and unify the concepts of transplant tolerance induction with those of reconstructive transplantation. Such therapies offer the promise of minimizing the risks, maximizing the benefits and optimizing outcomes of these innovative procedures.

Surgical and Technical Aspects of Hand Transplantation: is It Just Another Replant?

Hand Clinics. Nov, 2011  |  Pubmed ID: 22051392

The ultimate goal of hand allotransplantation is to achieve graft survival and useful long-term function. To achieve these goals, selection of the appropriate patient, detailed preoperative planning, and precise surgical technique are of paramount importance. Transplantation should be reserved for motivated consenting adults in good general heath, who are psychologically stable and have failed a trial of prosthetic use. While the key surgical steps of transplantation are similar to those of replantation, there are major differences. This article describes the steps in hand allotransplantation, and the importance of patient selection as well as preoperative and postoperative care.

Hand Transplantation

Hand Clinics. Nov, 2011  |  Pubmed ID: 22051398

Helping Hands: Caring for the Upper Extremity Transplant Patient

Critical Care Nursing Clinics of North America. Sep, 2011  |  Pubmed ID: 22054824

Caring for upper extremity transplant recipients can offer challenges and opportunities to nursing staff in combining new patient procedures, new technologies, and complex patient care needs including unique physical care, monitoring and observation, rehabilitation expectations, and psychiatric/psychosocial support. Medical professionals continue to be apprehensive about the risks of immunosuppressive therapy and the possibility of acute and chronic rejection. The sustained development and research into reliable, reduced-dose immunosuppression or immunomodulatory strategies could expand the life-enhancing benefits of reconstructive transplantation.

Technical Aspects of the Recipient Operation in Hand Transplantation

Journal of Reconstructive Microsurgery. Jan, 2012  |  Pubmed ID: 21811969

The goal of hand allotransplantation is to achieve graft survival and useful long-term function. To achieve these goals, precise surgical technique is of critical importance. The key surgical steps and sequence of events in hand allotransplantation are similar to major upper extremity replantations, but are modified to accommodate major conceptual differences that exist between the two procedures.

Histopathologic Characterization of Mild Rejection (grade I) in Skin Biopsies of Human Hand Allografts

Transplant International : Official Journal of the European Society for Organ Transplantation. Jan, 2012  |  Pubmed ID: 21981770

Mild skin rejection is a common observation in reconstructive transplantation. To enlighten the role of this inflammatory reaction we investigated markers for cellular and antibody mediated rejection, adhesion molecules and tolerance markers. Forty-seven skin biopsies (rejection grade I) of human hand allografts were investigated by immunohistochemistry (CD3, CD4, CD8, CD20, CD68, C4d, LFA-1, ICAM-1, E-selectin, P-selectin, VE-cadherin, HLA-DR, IDO, and Foxp3). Expression was read with respect to time after transplant. The infiltrate was mainly comprised of CD3+T-lymphocytes. Among these, CD8+cells were more prominent than CD4+cells. CD20+B-lymphocytes were sparse and CD68+macrophages were found in some, but not all samples (approximately 10% of the infiltrate). The CD4/CD8-ratio was increased after the first year. C4d staining was mainly positive in samples at time-points later than 1 year. Adhesion molecules LFA-1, ICAM-1, E-selectin, P-selectin, and VE-cadherin were found upregulated, and for P-selectin, expression increased with time after transplant. IDO expression was strongest at 3 months-1 year post-transplant and a tendency toward more Foxp3+ cells at later time points was observed. Mild skin rejection after hand transplantation presents with a T-cell dominated dermal cell infiltrate and upregulation of adhesion molecules. The role of C4d expression after year one remains to be elucidated.

IDO and Regulatory T Cell Support Are Critical for Cytotoxic T Lymphocyte-associated Ag-4 Ig-mediated Long-term Solid Organ Allograft Survival

Journal of Immunology (Baltimore, Md. : 1950). Jan, 2012  |  Pubmed ID: 22131334

Costimulatory blockade of CD28-B7 interaction with CTLA4Ig is a well-established strategy to induce transplantation tolerance. Although previous in vitro studies suggest that CTLA4Ig upregulates expression of the immunoregulatory enzyme IDO in dendritic cells, the relationship of CTLA4Ig and IDO in in vivo organ transplantation remains unclear. In this study, we studied whether concerted immunomodulation in vivo by CTLA4Ig depends on IDO. C57BL/6 recipients receiving a fully MHC-mismatched BALB/c heart graft treated with CTLA4Ig + donor-specific transfusion showed indefinite graft survival (>100 d) without signs of chronic rejection or donor specific Ab formation. Recipients with long-term surviving grafts had significantly higher systemic IDO activity as compared with rejectors, which markedly correlated with intragraft IDO and Foxp3 levels. IDO inhibition with 1-methyl-dl-tryptophan, either at transplant or at postoperative day 50, abrogated CTLA4Ig + DST-induced long-term graft survival. Importantly, IDO1 knockout recipients experienced acute rejection and graft survival comparable to controls. In addition, αCD25 mAb-mediated depletion of regulatory T cells (Tregs) resulted in decreased IDO activity and again prevented CTLA4Ig + DST induced indefinite graft survival. Our results suggest that CTLA4Ig-induced tolerance to murine cardiac allografts is critically dependent on synergistic cross-linked interplay of IDO and Tregs. These results have important implications for the clinical development of this costimulatory blocker.

Discussion: The Brigham and Women's Hospital Face Transplant Program: a Look Back

Plastic and Reconstructive Surgery. Jan, 2012  |  Pubmed ID: 22186588

The Psychological Assessment of Candidates for Reconstructive Hand Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. May, 2012  |  Pubmed ID: 22448727

Standardized psychological assessment of candidates for reconstructive hand transplantation (RHT) is a new approach in transplantation medicine. Currently, international guidelines and standardized criteria for the evaluation are not established. Patients suffering from the loss of a hand or an upper extremity have to cope with multiple challenges. For a selected group of patients, RHT represents an option for restoring natural function and for regaining daily living independence. The identification of at-risk patients and those requiring ongoing counseling due to poor coping or limited psychological resources are the primary focus of the psychological assessment. We have developed the 'Innsbruck Psychological Screening Program for Reconstructive Transplantation (iRT-PSP)' which utilizes a semi-structured interview and standardized psychological screening procedures and continuous follow-up ratings. Between January 2011 and October 2011, four candidates were evaluated using the iRT-PSP. Psychological impairments including social withdrawal, embarrassment, reduced self-esteem, and a depressive coping style were identified and poor quality of life was reported. The motivation for transplantation was diverse, depending on many factors such as bi- or unilateral impairment, native or accidental loss of hand, and social integration.

Hemiface Allotransplantation in the Mouse

Plastic and Reconstructive Surgery. Apr, 2012  |  Pubmed ID: 22456359

Rat models of experimental face transplantation have been widely used to study vascularized composite tissue allotransplantation. Because the mouse represents a superior species for vascularized composite tissue allotransplantation research, the authors developed a novel surgical technique with which to perform hemiface transplantation in mice. BALB/c hemifacial grafts were transplanted into BALB/c (group 1) or C57BL6 (group 2) recipients (n = 6 per group). Myocutaneous hemiface grafts including a vascular pedicle consisting of the common carotid artery and the external jugular vein were retrieved using superfine microsurgical instruments. The graft was transplanted orthotopically and revascularized using the recipient common carotid artery and external jugular vein for anastomosis applying a non-suture cuff technique. After an initial learning curve, the surgical procedure was performed with a constant and high success rate (78 percent). Operating time was comparable in all groups and lasted 120 ± 15 minutes for the donor and 150 ± 12 minutes for the recipient. All syngeneic grafts survived long term (>100 days). Allograft rejection in group 2 occurred within 14 ± 2 days. Hematoxylin and eosin stains of syngeneic grafts revealed unaltered muscle and skin histology. Allogeneic grafts gradually showed distinct rejection patterns progressing with time and similar to those observed after human face transplantation. This is the first description of a mouse hemiface allotransplantation model. The microsurgically demanding procedure may be used to investigate basic immunology and rejection and to address questions related to nerve regeneration in reconstructive face transplantation.

Animal Models for Basic and Translational Research in Reconstructive Transplantation

Birth Defects Research. Part C, Embryo Today : Reviews. Mar, 2012  |  Pubmed ID: 22457176

Reconstructive transplantation represents a bona fide option for select patients with devastating tissue loss, which could better restore the appearance, anatomy, and function than any other conventional treatment currently available. Despite favorable outcomes, broad clinical application of reconstructive transplantation is limited by the potential side effects of chronic multidrug immunosuppression. Thus, any reconstructive measures to improve these non-life-threatening conditions must address a delicate balance of risks and benefits. Today, several exciting novel therapeutic strategies, such as the implementation of cellular therapies including bone marrow or stem cells that integrate the concepts of immune regulation with those of nerve regeneration, are on the horizon. The development of reliable and reproducible small and large animal models is essential for the study of the unique immunological and biological aspects of vascularized composite allografts and to translate such novel immunoregulatory and tolerance-inducing strategies and therapeutic concepts from the bench to bedside. This review provides an overview of the multitude of small and large animal models that have been particularly designed for basic and translational research related to reconstructive transplantation.

Anesthetic Management in Upper Extremity Transplantation: the Pittsburgh Experience

Anesthesia and Analgesia. Sep, 2012  |  Pubmed ID: 22745115

Hand/forearm/arm transplants are vascularized composite allografts, which, unlike solid organs, are composed of multiple tissues including skin, muscle, tendons, vessels, nerves, lymph nodes, bone, and bone marrow. Over the past decade, 26 upper extremity transplantations were performed in the United States. The University of Pittsburgh Medical Center has the largest single center experience with 8 hand/forearm transplantations performed in 5 recipients between January 2008 and September 2010. Anesthetic management in the emerging field of upper extremity transplants must address protocol and procedure-specific considerations related to the role of regional blocks, effects of immunosuppressive drugs during transplant surgery, fluid and hemodynamic management in the microsurgical setting, and rigorous intraoperative monitoring during these often protracted procedures.

Prevention of Lethal Murine Pancreas Ischemia Reperfusion Injury is Specific for Tetrahydrobiopterin

Transplant International : Official Journal of the European Society for Organ Transplantation. Oct, 2012  |  Pubmed ID: 22805419

Tetrahydrobiopterin has been shown to efficiently abrogate ischemia reperfusion injury (IRI). However, it is unclear, whether its beneficial action relies on cofactor activity of one of the five known tetrahydrobiopterin-dependent reactions or on its antioxidative capacity. We therefore compared tetrahydrobiopterin with the pterin derivate tetrahydroneopterin (similar biochemical properties, but no nitric oxide synthase cofactor activity) and the antioxidants vitamin C and 5-methyltetrahydrofolate. Donor mice were pretreated with tetrahydrobiopterin, tetrahydroneopterin, vitamin C, or 5-methyltetrahydrofolate. Pancreatic grafts were subjected to 16-h cold ischemia time and implanted in syngeneic recipients. Untreated and nontransplanted animals served as controls. Following 2-h reperfusion, microcirculation was analyzed by intravital fluorescence microscopy. Graft damage was assessed by histology and nitrotyrosine immunostaining, and tetrahydrobiopterin levels were determined by HPLC. Recipient survival served as ultimate readout. Prolonged cold ischemia time resulted in microcirculatory breakdown. Only tetrahydrobiopterin pretreatment succeeded to preserve the capillary net, whereas all other compounds showed no beneficial effects. Along with increased intragraft tetrahydrobiopterin levels during recovery and implantation, only tetrahydrobiopterin pretreatment led to significant reduction of IRI-related parenchymal damage enabling recipient survival. These results show a striking superiority of tetrahydrobiopterin in preventing lethal IRI compared with related compounds and suggest nitric oxide synthases as treatment target.

Mechanisms and Mediators of Inflammation: Potential Models for Skin Rejection and Targeted Therapy in Vascularized Composite Allotransplantation

Clinical & Developmental Immunology. 2012  |  Pubmed ID: 23049603

Vascularized composite allotransplantation (VCA) is an effective treatment option for patients suffering from limb loss or severe disfigurement. However, postoperative courses of VCA recipients have been complicated by skin rejection, and long-term immunosuppression remains a necessity for allograft survival. To widen the scope of this quality-of-life improving procedure minimization of immunosuppression in order to limit risks and side effects is needed. In some aspects, the molecular mechanisms and dynamics of skin allograft rejection seem similar to inflammatory skin conditions. T cells are key players in skin rejection and are recruited to the skin via activation of adhesion molecules, cytokines, and chemokines. Blocking these molecules has not only shown success in the treatment of inflammatory dermatoses, but also prolonged graft survival in various models of solid organ transplantation. In addition to T cell recruitment, ectopic lymphoid structures within the allograft associated with chronic rejection in solid organ transplantation might contribute to the strong alloimmune response towards the skin. Selectively targeting the molecules involved offers exciting novel therapeutic options in the prevention and treatment of skin rejection after VCA.

Minimizing Immunosuppression in Hand Transplantation

Expert Review of Clinical Immunology. Sep, 2012  |  Pubmed ID: 23078064

Hand transplantation, despite all initial skepticism, has developed from myth to reality over the past decade and has shown highly encouraging immunological and functional outcomes. However, the requirement of life-long, multidrug immunosuppression bearing the risk of serious side effects still remains the limiting factor for widespread clinical application of this novel reconstructive modality. Recent advances in immunosuppressive drug development and the design of novel cell-based therapeutic strategies that take into consideration the unique immunological and biological aspects of vascularized composite allografts have shown favorable results with regard to minimization of immunosuppressive medication and tolerance induction in both translational animal studies and first clinical trials in reconstructive transplantation. This review provides an overview of the current available conventional treatment protocols and novel immunosuppression minimization concepts for hand transplantation, which ultimately could significantly favor the risk-benefit ratio for this life-changing type of transplant.

Real-time Three-dimensional Fourier-domain Optical Coherence Tomography Video Image Guided Microsurgeries

Journal of Biomedical Optics. Aug, 2012  |  Pubmed ID: 23224164

The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10 volume/s for an image volume size of 160 × 80 × 1024(X × Y × Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8 mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed "ultra microvascular" feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter ~0.1 mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment.

Upper-extremity Transplantation Using a Cell-based Protocol to Minimize Immunosuppression

Annals of Surgery. Feb, 2013  |  Pubmed ID: 23001085

To minimize maintenance immunosuppression in upper-extremity transplantation to favor the risk-benefit balance of this procedure.

Biomarker Discovery in Transplantation--proteomic Adventure or Mission Impossible?

Clinical Biochemistry. Apr, 2013  |  Pubmed ID: 23089107

Optimal management of transplanted organs requires specific and sensitive biomarkers for immunologic graft monitoring and subsequently patient tailored treatment. Proteomic science has emerged as an attractive tool in clinical biomarker research generating massive amounts of proteomic-driven data. However, critical interpretation of these data requires basic knowledge of proteomic principles and technology. This review provides an overview of proteomic approaches along with their advantages and limitations. Furthermore, this article summarizes the current status of biomarker achievements in the different areas of solid organ transplantation and discusses the hurdles that have precluded routine clinical application of these promising markers so far.

Trends in Immunosuppression After Pancreas Transplantation: What is in the Pipeline?

Current Opinion in Organ Transplantation. Feb, 2013  |  Pubmed ID: 23254700

To provide an overview of currently available immunosuppressive strategies and novel therapeutic developments in pancreas transplantation.

Review of the Early Diagnoses and Assessment of Rejection in Vascularized Composite Allotransplantation

Clinical & Developmental Immunology. 2013  |  Pubmed ID: 23431325

The emerging field of vascular composite allotransplantation (VCA) has become a clinical reality. Building upon cutting edge understandings of transplant surgery and immunology, complex grafts such as hands and faces can now be transplanted with success. Many of the challenges that have historically been limiting factors in transplantation, such as rejection and the morbidity of immunosuppression, remain challenges in VCA. Because of the accessibility of most VCA grafts, and the highly immunogenic nature of the skin in particular, VCA has become the focal point for cross-disciplinary approaches to developing novel approaches for some of the most challenging immunological problems in transplantation, particularly the early diagnoses and assessment of rejection. This paper provides a historically oriented introduction to the field of organ transplantation and the evolution of VCA.

Standardizing Skin Biopsy Sampling to Assess Rejection in Vascularized Composite Allotransplantation

Clinical Transplantation. Mar-Apr, 2013  |  Pubmed ID: 23452279

Over 70 hands and 20 faces have been transplanted during the past 13 yr, which have shown good to excellent functional and esthetic outcomes. However, (skin) rejection episodes complicate the post-operative courses of hand and face transplant recipients and are still a major obstacle to overcome after reconstructive allotransplantation. This article summarizes all relevant information on the skin component and rejection of a vascularized composite allograft. As more and more centers plan to implement a vascularized composite allotransplantation (VCA) program, we further develop guidelines and recommendations on collection and processing of skin biopsies from hand and face allograft recipients. This will help to standardize post-operative monitoring, avoid pitfalls for those new in the field and facilitate comparison of data on VCA between centers.

Targeting the Kv1.3 Potassium Channel for Immunosuppression in Vascularized Composite Allotransplantation - a Pilot Study

Transplant International : Official Journal of the European Society for Organ Transplantation. May, 2013  |  Pubmed ID: 23489391

Kv1.3-channels are critically involved in activation and function of effector memory T cells. Blocking Kv1.3-channels was investigated for its effect on skin rejection in a rat limb-transplantation-model. Animals received the Kv1.3-blocker correolide C systemically or locally as intra-graft-treatment in combination with tacrolimus. Systemic (intraperitoneal) administration of correolide C resulted in slight, but significant prolongation of allograft survival compared with untreated and placebo treated controls. In 4/6 correolide C treated animals, histology showed an intact epidermis and a mild infiltrate by day 10. High correolide C plasma trough levels correlated with prolonged allograft survival. A decrease in CD4+ and CD8+ effector memory T cells was observed in allograft skin, peripheral blood and the spleen on day 5. When applied subcutaneously in combination with systemic tacrolimus (30 days+/-anti-lymphocyte serum) detectable, but insignificant prolongation of graft survival was achieved. 2/5 animals showed an intact epidermis and a mild infiltrate until day 45. Tapering systemic tacrolimus and weaning on day 50 resulted in rejection by day 55, regardless of local correolide C treatment. Subcutaneous injection did not lead to systemic plasma levels. The Kv1.3-channel is a potential drug target worth exploring in more detail for immunosuppression in vascularized composite allotransplantation.

Immunology of Vascularized Composite Allografts

Clinical & Developmental Immunology. 2013  |  Pubmed ID: 23573113

Nitric Oxide-mediated Regulation of Ferroportin-1 Controls Macrophage Iron Homeostasis and Immune Function in Salmonella Infection

The Journal of Experimental Medicine. May, 2013  |  Pubmed ID: 23630227

Nitric oxide (NO) generated by inducible NO synthase 2 (NOS2) affects cellular iron homeostasis, but the underlying molecular mechanisms and implications for NOS2-dependent pathogen control are incompletely understood. In this study, we found that NO up-regulated the expression of ferroportin-1 (Fpn1), the major cellular iron exporter, in mouse and human cells. Nos2(-/-) macrophages displayed increased iron content due to reduced Fpn1 expression and allowed for an enhanced iron acquisition by the intracellular bacterium Salmonella typhimurium. Nos2 gene disruption or inhibition of NOS2 activity led to an accumulation of iron in the spleen and splenic macrophages. Lack of NO formation resulted in impaired nuclear factor erythroid 2-related factor-2 (Nrf2) expression, resulting in reduced Fpn1 transcription and diminished cellular iron egress. After infection of Nos2(-/-) macrophages or mice with S. typhimurium, the increased iron accumulation was paralleled by a reduced cytokine (TNF, IL-12, and IFN-γ) expression and impaired pathogen control, all of which were restored upon administration of the iron chelator deferasirox or hyperexpression of Fpn1 or Nrf2. Thus, the accumulation of iron in Nos2(-/-) macrophages counteracts a proinflammatory host immune response, and the protective effect of NO appears to partially result from its ability to prevent iron overload in macrophages.

Composite Tissue Transplantation

Methods in Molecular Biology (Clifton, N.J.). 2013  |  Pubmed ID: 23775733

Composite tissue transplantation is an emerging new era in transplant medicine and has become a viable reconstructive option for patients with large and devastating tissue defects. Advances in microsurgical techniques, transplant immunology and the development of potent immunosuppressive agents have enabled the realization of such types of transplants. Over the past decade, a rapidly growing number of face and upper extremity transplantations have been performed worldwide with highly encouraging outcomes. However, despite the fact that surgical, immunological and functional results are highly encouraging, the need for long-term and high-dose immunosuppression to enable graft survival and to treat/reverse acute skin rejection episodes remains a pace-limiting obstacle towards wide spread application. In this chapter we review the history and development of this novel field, the functional and immunological outcomes based on the world experience, unique biological features of such transplants, mechanisms and treatment protocols for acute skin rejection, as well as novel concepts for immune modulation and tolerance induction.

A Novel Laser-Doppler Flowmetry Assisted Murine Model of Acute Hindlimb Ischemia-reperfusion for Free Flap Research

PloS One. 2013  |  Pubmed ID: 23840492

Suitable and reproducible experimental models of translational research in reconstructive surgery that allow in-vivo investigation of diverse molecular and cellular mechanisms are still limited. To this end we created a novel murine model of acute hindlimb ischemia-reperfusion to mimic a microsurgical free flap procedure. Thirty-six C57BL6 mice (n = 6/group) were assigned to one control and five experimental groups (subject to 6, 12, 96, 120 hours and 14 days of reperfusion, respectively) following 4 hours of complete hindlimb ischemia. Ischemia and reperfusion were monitored using Laser-Doppler Flowmetry. Hindlimb tissue components (skin and muscle) were investigated using histopathology, quantitative immunohistochemistry and immunofluorescence. Despite massive initial tissue damage induced by ischemia-reperfusion injury, the structure of the skin component was restored after 96 hours. During the same time, muscle cells were replaced by young myotubes. In addition, initial neuromuscular dysfunction, edema and swelling resolved by day 4. After two weeks, no functional or neuromuscular deficits were detectable. Furthermore, upregulation of VEGF and tissue infiltration with CD34-positive stem cells led to new capillary formation, which peaked with significantly higher values after two weeks. These data indicate that our model is suitable to investigate cellular and molecular tissue alterations from ischemia-reperfusion such as occur during free flap procedures.

Microvascular Anastomosis Guidance and Evaluation Using Real-time Three-dimensional Fourier-domain Doppler Optical Coherence Tomography

Journal of Biomedical Optics. Nov, 2013  |  Pubmed ID: 23856833

Vascular and microvascular anastomoses are critical components of reconstructive microsurgery, vascular surgery, and transplant surgery. Intraoperative surgical guidance using a surgical imaging modality that provides an in-depth view and three-dimensional (3-D) imaging can potentially improve outcome following both conventional and innovative anastomosis techniques. Objective postoperative imaging of the anastomosed vessel can potentially improve the salvage rate when combined with other clinical assessment tools, such as capillary refill, temperature, blanching, and skin turgor. Compared to other contemporary postoperative monitoring modalities--computed tomography angiograms, magnetic resonance (MR) angiograms, and ultrasound Doppler--optical coherence tomography (OCT) is a noninvasive high-resolution (micron-level), high-speed, 3-D imaging modality that has been adopted widely in biomedical and clinical applications. For the first time, to the best of our knowledge, the feasibility of real-time 3-D phase-resolved Doppler OCT (PRDOCT) as an assisted intra- and postoperative imaging modality for microvascular anastomosis of rodent femoral vessels is demonstrated, which will provide new insights and a potential breakthrough to microvascular and supermicrovascular surgery.

Near-infrared Lymphography As a Minimally Invasive Modality for Imaging Lymphatic Reconstitution in a Rat Orthotopic Hind Limb Transplantation Model

Transplant International : Official Journal of the European Society for Organ Transplantation. Sep, 2013  |  Pubmed ID: 23879384

Wider application of vascularized composite allotransplantation (VCA) is limited by the need for chronic immunosuppression. Recent data suggest that the lymphatic system plays an important role in mediating rejection. This study used near-infrared (NIR) lymphography to describe lymphatic reconstitution in a rat VCA model. Syngeneic (Lewis-Lewis) and allogeneic (Brown Norway-Lewis) rat orthotopic hind limb transplants were performed without immunosuppression. Animals were imaged pre- and postoperatively using indocyanine green (ICG) lymphography. Images were collected using an NIR imaging system. Co-localization was achieved through use of an acrylic paint/hydrogen peroxide mixture. In all transplants, ICG first crossed graft suture lines on postoperative day (POD) 5. Clinical signs of rejection also appeared on POD 5 in allogeneic transplants, with most exhibiting Grade 3 rejection by POD 6. Injection of an acrylic paint/hydrogen peroxide mixture on POD 5 confirmed the existence of continuous lymphatic vessels crossing the suture line and draining into the inguinal lymph node. NIR lymphography is a minimally invasive imaging modality that can be used to study lymphatic vessels in a rat VCA model. In allogeneic transplants, lymphatic reconstitution correlated with clinical rejection. Lymphatic reconstitution may represent an early target for immunomodulation.

Discussion: Lessons Learned from Simultaneous Face and Bilateral Hand Allotransplantation

Plastic and Reconstructive Surgery. Aug, 2013  |  Pubmed ID: 23897340

Overcoming Cross-Gender Differences and Challenges in Le Fort-Based, Craniomaxillofacial Transplantation With Enhanced Computer-Assisted Technology

Annals of Plastic Surgery. Oct, 2013  |  Pubmed ID: 24025655

Sex-specific anthropometrics, skin texture/adnexae mismatch, and social apprehension have prevented cross-gender facial transplantation from evolving. However, the scarce donor pool and extreme waitlist times are currently suboptimal. Our objective was to (1) perform and assess cadaveric facial transplantation for each sex-mismatched scenario using virtual planning with cutting guide fabrication and (2) review the advantages/disadvantages of cross-gender facial transplantation.

Impact of Donor-specific Antibodies in Reconstructive Transplantation

Expert Review of Clinical Immunology. Sep, 2013  |  Pubmed ID: 24070047

For many devastating injuries and tissue defects where conventional reconstruction is not possible, reconstructive transplantation such as hand and face transplantation has become a viable alternative. This novel approach allows for improved restoration of appearance, anatomy and function not feasible by other available treatment options. However, clinical management of these injuries prior to transplantation frequently requires multiple blood transfusion or skin grafts resulting in the formation of alloantibodies (anti-HLA IgG Abs) and a high degree of sensitization. The role of donor-specific antibodies (DSA) and mechanisms of antibody-mediated rejection (AMR) in reconstructive transplantation are still largely unknown. Thus there is an imminent need to develop a better understanding of the mechanisms related to DSA and AMR after reconstructive transplantation. In this review, we will define the role of DSA and mechanisms of AMR in reconstructive transplantation and compare them to established measures and treatment concepts in solid organ transplantation.

Current Concepts and Systematic Review of Vascularized Composite Allotransplantation of the Abdominal Wall

Clinical Transplantation. Sep, 2013  |  Pubmed ID: 24102820

Abdominal wall vascularized composite allotransplantation (AW-VCA) is a rarely utilized technique for large composite abdominal wall defects. The goal of this article is to systematically review the literature and current concepts of AW-VCA, outline the challenges ahead, and provide an outlook for the future.

Immunomodulatory Effects of Adipose-Derived Stem Cells: Fact or Fiction?

BioMed Research International. 2013  |  Pubmed ID: 24106704

Adipose-derived stromal cells (ASCs) are often referred to as adipose-derived stem cells due to their potential to undergo multilineage differentiation. Their promising role in tissue engineering and ability to modulate the immune system are the focus of extensive research. A number of clinical trials using ASCs are currently underway to better understand the role of such cell niche in enhancing or suppressing the immune response. If governable, such immunoregulatory role would find application in several conditions in which an immune response is present (i.e., autoimmune conditions) or feared (i.e., solid organ or reconstructive transplantation). Although allogeneic ASCs have been shown to prevent acute GvHD in both preclinical and clinical studies, their potential warrants further investigation. Well-designed and standardized clinical trials are necessary to prove the role of ASCs in the treatment of immune disorders or prevention of tissue rejection. In this paper we analyze the current literature on the role of ASCs in immunomodulation in vitro and in vivo and discuss their potential in regulating the immune system in the context of transplantation.

Cutaneous Collateral Axonal Sprouting Re-innervates the Skin Component and Restores Sensation of Denervated Swine Osteomyocutaneous Alloflaps

PloS One. 2013  |  Pubmed ID: 24204901

Reconstructive transplantation such as extremity and face transplantation is a viable treatment option for select patients with devastating tissue loss. Sensorimotor recovery is a critical determinant of overall success of such transplants. Although motor function recovery has been extensively studied, mechanisms of sensory re-innervation are not well established. Recent clinical reports of face transplants confirm progressive sensory improvement even in cases where optimal repair of sensory nerves was not achieved. Two forms of sensory nerve regeneration are known. In regenerative sprouting, axonal outgrowth occurs from the transected nerve stump while in collateral sprouting, reinnervation of denervated tissue occurs through growth of uninjured axons into the denervated tissue. The latter mechanism may be more important in settings where transected sensory nerves cannot be re-apposed. In this study, denervated osteomyocutaneous alloflaps (hind- limb transplants) from Major Histocompatibility Complex (MHC)-defined MGH miniature swine were performed to specifically evaluate collateral axonal sprouting for cutaneous sensory re-innervation. The skin component of the flap was externalized and serial skin sections extending from native skin to the grafted flap were biopsied. In order to visualize regenerating axonal structures in the dermis and epidermis, 50 um frozen sections were immunostained against axonal and Schwann cell markers. In all alloflaps, collateral axonal sprouts from adjacent recipient skin extended into the denervated skin component along the dermal-epidermal junction from the periphery towards the center. On day 100 post-transplant, regenerating sprouts reached 0.5 cm into the flap centripetally. Eight months following transplant, epidermal fibers were visualized 1.5 cm from the margin (rate of regeneration 0.06 mm per day). All animals had pinprick sensation in the periphery of the transplanted skin within 3 months post-transplant. Restoration of sensory input through collateral axonal sprouting can revive interaction with the environment; restore defense mechanisms and aid in cortical re-integration of vascularized composite allografts.

Vascularized Composite Allotransplantation

Current Opinion in Organ Transplantation. Dec, 2013  |  Pubmed ID: 24220046

Immunosuppression and Monitoring of Rejection in Hand Transplantation

Techniques in Hand & Upper Extremity Surgery. Dec, 2013  |  Pubmed ID: 24275762

Advances in vascularized composite allotransplantation over the last decade have achieved significant milestones in basic science and translational research, as well as clinically with highly encouraging functional and immunologic outcomes. However, certain immunologic challenges remain. In particular, although tolerance has been induced to nearly all components of a hand allograft in experimental models, the skin component may still be subject to acute rejection episodes. Currently, conventional immunosuppressive protocols have been successful at preventing allograft loss; however, they have not prevented episodes of acute skin rejection. Furthermore, the profound side effect profile of the life-long, high-dose, multidrug immunosuppression regimen that is necessary to maintain a viable graft alters the risk to benefit ratio of this non-life-saving procedure. Therefore, there must be a concerted effort in the scientific community to develop novel protocols to either minimize immunosuppression or to induce tolerance to the allograft to promote the widespread application of this life-changing procedure.

Monocytes Loaded with Indocyanine Green As Active Homing Contrast Agents Permit Optical Differentiation of Infectious and Non-infectious Inflammation

PloS One. 2013  |  Pubmed ID: 24282595

Distinguishing cutaneous infection from sterile inflammation is a diagnostic challenge and currently relies upon subjective interpretation of clinical parameters, microbiological data, and nonspecific imaging. Assessing characteristic variations in leukocytic infiltration may provide more specific information. In this study, we demonstrate that homing of systemically administered monocytes tagged using indocyanine green (ICG), an FDA-approved near infrared dye, may be assessed non-invasively using clinically-applicable laser angiography systems to investigate cutaneous inflammatory processes. RAW 264.7 mouse monocytes co-incubated with ICG fluoresce brightly in the near infrared range. In vitro, the loaded cells retained the ability to chemotax toward monocyte chemotactic protein-1. Following intravascular injection of loaded cells into BALB/c mice with induced sterile inflammation (Complete Freund's Adjuvant inoculation) or infection (Group A Streptococcus inoculation) of the hind limb, non-invasive whole animal imaging revealed local fluorescence at the inoculation site. There was significantly higher fluorescence of the inoculation site in the infection model than in the inflammation model as early as 2 hours after injection (p<0.05). Microscopic examination of bacterial inoculation site tissue revealed points of near infrared fluorescence, suggesting the presence of ICG-loaded cells. Development of a non-invasive technique to rapidly image inflammatory states without radiation may lead to new tools to distinguish infectious conditions from sterile inflammatory conditions at the bedside.

Preoperative Anemia and Postoperative Outcomes in Immediate Breast Reconstructive Surgery: A Critical Analysis of 10,958 Patients from the ACS-NSQIP Database

Plastic and Reconstructive Surgery. Global Open. Aug, 2013  |  Pubmed ID: 25289224

Preoperative anemia is independently associated with adverse outcomes after general and cardiac surgery. Outcomes after breast reconstruction are not established. We assessed the effect of preoperative anemia on 30-day postoperative morbidity and length of hospital stay (LOS) in patients undergoing immediate breast reconstruction.

An Overview of Psychosocial Assessment Procedures in Reconstructive Hand Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. May, 2014  |  Pubmed ID: 24164333

There have been more than 90 hand and upper extremity transplants performed worldwide. Functional and sensory outcomes have been reported in several studies, but little is known about the psychosocial outcomes. A comprehensive systematic literature review was performed, addressing the psychosocial impact of reconstructive hand transplantation. This review provides an overview of psychosocial evaluation protocols and identifies standards in this novel and exciting field. Essentials of the psychosocial assessment are discussed and a new protocol, the 'Chauvet Protocol', representing a standardized assessment protocol for future multicenter psychosocial trials is being introduced.

Antibody-mediated Rejection in Hand Transplantation

Transplant International : Official Journal of the European Society for Organ Transplantation. Feb, 2014  |  Pubmed ID: 24266875

Clinical relevance of antibody-mediated rejection (ABMR) in vascularized composite allotransplantation (VCA) has not been defined. We herein describe a novel type of donor-specific antibody (DSA) and B-cell-associated rejection in hand transplantation. In 2003, a bilateral forearm transplantation was performed on a 42-year-old male patient. In 2012, the patient presented with edematous hands and forearms without skin lesions. Punch skin biopsies revealed rejection grade Banff II. Immunohistochemical analysis identified large aggregates of CD20 + lymphocytes with an architecture resembling lymph nodes. De novo DSA was found at a high level. Steroid treatment was ineffective, but administration of rituximab resulted in complete remission of clinical symptoms, evaporation of B-cell aggregates, and disappearance of DSA. We herein report the first case of what we suggest is an ABMR in VCA occurring at 9 years after forearm transplantation. Rituximab therapy successfully reversed the event.

Preliminary Development of a Workstation for Craniomaxillofacial Surgical Procedures: Introducing a Computer-assisted Planning and Execution System

The Journal of Craniofacial Surgery. Jan, 2014  |  Pubmed ID: 24406592

Facial transplantation represents one of the most complicated scenarios in craniofacial surgery because of skeletal, aesthetic, and dental discrepancies between donor and recipient. However, standard off-the-shelf vendor computer-assisted surgery systems may not provide custom features to mitigate the increased complexity of this particular procedure. We propose to develop a computer-assisted surgery solution customized for preoperative planning, intraoperative navigation including cutting guides, and dynamic, instantaneous feedback of cephalometric measurements/angles as needed for facial transplantation and other related craniomaxillofacial procedures.

A P38MAPK/MK2 Signaling Pathway Leading to Redox Stress, Cell Death and Ischemia/reperfusion Injury

Cell Communication and Signaling : CCS. 2014  |  Pubmed ID: 24423080

Many diseases and pathological conditions are characterized by transient or constitutive overproduction of reactive oxygen species (ROS). ROS are causal for ischemia/reperfusion (IR)-associated tissue injury (IRI), a major contributor to organ dysfunction or failure. Preventing IRI with antioxidants failed in the clinic, most likely due to the difficulty to timely and efficiently target them to the site of ROS production and action. IR is also characterized by changes in the activity of intracellular signaling molecules including the stress kinase p38MAPK. While ROS can cause the activation of p38MAPK, we recently obtained in vitro evidence that p38MAPK activation is responsible for elevated mitochondrial ROS levels, thus suggesting a role for p38MAPK upstream of ROS and their damaging effects.

Establishing Cephalometric Landmarks for the Translational Study of Le Fort-based Facial Transplantation in Swine: Enhanced Applications Using Computer-assisted Surgery and Custom Cutting Guides

Plastic and Reconstructive Surgery. May, 2014  |  Pubmed ID: 24445879

Le Fort-based, maxillofacial allotransplantation is a reconstructive alternative gaining clinical acceptance. However, the vast majority of single-jaw transplant recipients demonstrate less-than-ideal skeletal and dental relationships, with suboptimal aesthetic harmony. The purpose of this study was to investigate reproducible cephalometric landmarks in a large-animal model, where refinement of computer-assisted planning, intraoperative navigational guidance, translational bone osteotomies, and comparative surgical techniques could be performed.

The Neck As a Preferred Recipient Site for Vascularized Composite Allotransplantation in the Mouse

Plastic and Reconstructive Surgery. Feb, 2014  |  Pubmed ID: 24469184

The mouse is still considered the premier model in basic immunologic and transplant-related research. However, because of its much smaller size, the mouse has proven to be a technically difficult and physiologically fragile model from a surgical standpoint. That is why only a few studies currently use mouse models in vascularized composite allotransplantation. The purpose of this study therefore was to develop a reproducible and reliable surgical technique in the mouse for future vascularized composite allotransplantation studies.

Diagnosing Skin Rejection in Vascularized Composite Allotransplantation: Advances and Challenges

Clinical Transplantation. Mar, 2014  |  Pubmed ID: 24476538

Refinements in microsurgical techniques coupled with advances in immunosuppressive and immunomodulatory protocols have enabled broader clinical application of vascularized composite allotransplantation (VCA) with encouraging immunological, functional, and esthetic results. However, skin rejection remains a significant obstacle and a serious complication for VCA recipients. Clinical and histopathological features of rejection in VCA have been described in a number of studies, which led to the development of an international consensus on the classification guidelines of rejection in the context of VCA. Nevertheless, currently available diagnostic modalities still have several limitations and shortcomings that can pose a significant diagnostic challenge, particularly when signs of rejection are found to be equivocal. In this review, we provide a critical analysis of these advances and challenges in diagnosing skin rejection. Specifically, we highlight the gaps in understanding of rejection mechanisms, the shortfalls in correlating cellular, molecular, and clinicopathologic markers with rejection grades, deficiencies in defining chronic rejection, and antibody-mediated rejection after VCA, as well as providing an outlook on novel concepts, such as the utilization of advanced computational analyses and cross-disciplinary diagnostic approaches.

Using the Dorsal, Cavernosal, and External Pudendal Arteries for Penile Transplantation: Technical Considerations and Perfusion Territories

Plastic and Reconstructive Surgery. Jul, 2014  |  Pubmed ID: 24622570

Penile transplantation may provide improved outcomes compared with autogenous phalloplastic reconstruction. The optimal approach to vascularizing penile allografts is unknown. In penile replantation, typically only the dorsal arteries are repaired, but using the cavernosal and external pudendal arteries may improve erectile function and shaft skin perfusion, respectively. The authors sought to demonstrate the technical feasibility of using the dorsal, cavernosal, and external pudendal vessels for penile transplantation and to assess differences in their perfusion territories.

Donor Age Negatively Affects the Immunoregulatory Properties of Both Adipose and Bone Marrow Derived Mesenchymal Stem Cells

Transplant Immunology. May, 2014  |  Pubmed ID: 24632513

Age negatively impacts the biologic features of mesenchymal stem cells (MSCs), including decreased expansion kinetics and differentiation potential. Clinically, donor-age may be within a wide spectrum; therefore, investigation of the role of donor's age on immunoregulatory potential is of critical importance to translate stem cell therapies from bench to bedside.

Characterization, Prophylaxis, and Treatment of Infectious Complications in Craniomaxillofacial and Upper Extremity Allotransplantation: a Multicenter Perspective

Plastic and Reconstructive Surgery. Apr, 2014  |  Pubmed ID: 24675206

Vascularized composite allotransplants consist of heterogeneous tissues from different germ layers, which include skin, muscle, bone, fat, nerves, and lymph nodes. The antigenic diversity of these tissues, particularly of the highly immunogenic skin component, necessitates potent immunosuppressive regimens similar to that of some solid organ transplants. Indeed, the lifelong, high-dose, multidrug immunosuppressive protocols expose vascularized composite allotransplant recipients to considerable risk of infectious, metabolic, and neoplastic sequelae. In this article, the authors review the infectious risk to patients after vascularized composite allotransplantation, with special attention to the somewhat limited experience with the prophylaxis and treatment of infections after this innovative reconstructive surgery.

Facial Transplantation: the First 9 Years

Lancet (London, England). Dec, 2014  |  Pubmed ID: 24783986

Since the first facial transplantation in 2005, 28 have been done worldwide with encouraging immunological, functional, psychological, and aesthetic outcomes. Unlike solid organ transplantation, which is potentially life-saving, facial transplantation is life-changing. This difference has generated ethical concerns about the exposure of otherwise young and healthy individuals to the sequelae of lifelong, high-dose, multidrug immunosuppression. Nevertheless, advances in immunomodulatory and immunosuppressive protocols, microsurgical techniques, and computer-aided surgical planning have enabled broader clinical application of this procedure to patients. Although episodes of acute skin rejection continue to pose a serious threat to face transplant recipients, all cases have been controlled with conventional immunosuppressive regimens, and no cases of chronic rejection have been reported.

Case Series on Defense Mechanisms in Patients for Reconstructive Hand Transplantation: Consideration on Transplant Defense Concept

Annals of Transplantation : Quarterly of the Polish Transplantation Society. 2014  |  Pubmed ID: 24841554

The technical demands of reconstructive hand transplantation (RHT) and need for complex multidisciplinary care have led to intense research efforts to improve patient care and outcomes. However, RHT is an extraordinary life event which carries the potential for long-term consequences including psychological distress, which invokes coping and defense mechanisms.

Lymphoid Neogenesis in Skin of Human Hand, Nonhuman Primate, and Rat Vascularized Composite Allografts

Transplant International : Official Journal of the European Society for Organ Transplantation. Sep, 2014  |  Pubmed ID: 24853399

The mechanisms of skin rejection in vascularized composite allotransplantation (VCA) remain incompletely understood. The formation of tertiary lymphoid organs (TLO) in hand transplantation has been recently described. We assess this phenomenon in experimental and clinical VCA rejection. Skin biopsies of human (n = 187), nonhuman primate (n = 11), and rat (n = 15) VCAs were analyzed for presence of TLO. A comprehensive immunohistochemical assessment (characterization of the cell infiltrate, expression of adhesion molecules) including staining for peripheral node addressin (PNAd) was performed and correlated with rejection and time post-transplantation. TLO were identified in human, nonhuman primate, and rat skin samples. Expression of PNAd was increased in the endothelium of vessels upon rejection in human skin (P = 0.003) and correlated with B- and T-lymphocyte numbers and LFA-1 expression. PNAd expression was observed at all time-points after transplantation and increased significantly after year 5. In nonhuman primate skin, PNAd expression was found during inflammatory conditions early and late after transplantation. In rat skin, PNAd expression was strongly associated with acute rejection and time post-transplantation. Lymphoid neogenesis and TLO formation can be uniformly found in experimental and human VCA. PNAd expression in vascular endothelium correlates with skin rejection and T- and B-cell infiltration.

The Misuse of the Terminology "standard of Care" Hampers Innovations in Surgery

Annals of Surgery. Dec, 2014  |  Pubmed ID: 24854452

Taming Inflammation by Targeting Cytokine Signaling: New Perspectives in the Induction of Transplantation Tolerance

Immunotherapy. 2014  |  Pubmed ID: 24896631

Transplantation tolerance remains an elusive goal, partly due to limitations in our understanding of the interplay between inflammatory mediators and their role in the activation and regulation of T lymphocytes. Although multiple mechanisms acting both centrally and peripherally are responsible for tolerance induction, the signaling pathways leading to activation or regulation of adaptive immunity are often complex, branched, redundant and modulated by the microenvironment's inflammatory milieu. Accumulating evidence clearly indicates that inflammatory cytokines limit the tolerogenic potential of immunomodulatory protocols by supporting priming of the immune system and counteracting regulatory mechanisms, ultimately promoting rejection. In this review, we summarize recent progress in the development of novel therapeutics to manipulate this inflammatory environment and achievements in targeted inhibition of inflammatory cytokine signaling. Ultimately, robust transplant tolerance induction will probably require a multifaceted, holistic approach that integrates the various mechanisms of tolerance induction, incorporates the dynamic alterations in costimulatory requirements of alloreactive T cells, while maintaining endogenous mechanisms of immune regulation.

Insights from Computational Modeling in Inflammation and Acute Rejection in Limb Transplantation

PloS One. 2014  |  Pubmed ID: 24926998

Acute skin rejection in vascularized composite allotransplantation (VCA) is the major obstacle for wider adoption in clinical practice. This study utilized computational modeling to identify biomarkers for diagnosis and targets for treatment of skin rejection. Protein levels of 14 inflammatory mediators in skin and muscle biopsies from syngeneic grafts [n = 10], allogeneic transplants without immunosuppression [n = 10] and allografts treated with tacrolimus [n = 10] were assessed by multiplexed analysis technology. Hierarchical Clustering Analysis, Principal Component Analysis, Random Forest Classification and Multinomial Logistic Regression models were used to segregate experimental groups. Based on Random Forest Classification, Multinomial Logistic Regression and Hierarchical Clustering Analysis models, IL-4, TNF-α and IL-12p70 were the best predictors of skin rejection and identified rejection well in advance of histopathological alterations. TNF-α and IL-12p70 were the best predictors of muscle rejection and also preceded histopathological alterations. Principal Component Analysis identified IL-1α, IL-18, IL-1β, and IL-4 as principal drivers of transplant rejection. Thus, inflammatory patterns associated with rejection are specific for the individual tissue and may be superior for early detection and targeted treatment of rejection.

Injectable Bioadhesive Hydrogels with Innate Antibacterial Properties

Nature Communications. 2014  |  Pubmed ID: 24958189

Surgical site infections cause significant postoperative morbidity and increased healthcare costs. Bioadhesives used to fill surgical voids and support wound healing are typically devoid of antibacterial activity. Here we report novel syringe-injectable bioadhesive hydrogels with inherent antibacterial properties prepared from mixing polydextran aldehyde and branched polyethylenimine. These adhesives kill both Gram-negative and Gram-positive bacteria, while sparing human erythrocytes. An optimal composition of 2.5 wt% oxidized dextran and 6.9 wt% polyethylenimine sets within seconds forming a mechanically rigid (~1,700 Pa) gel offering a maximum adhesive stress of ~2.8 kPa. A murine infection model showed that the adhesive is capable of killing Streptococcus pyogenes introduced subcutaneously at the bioadhesive's surface, with minimal inflammatory response. The adhesive was also effective in a cecal ligation and puncture model, preventing sepsis and significantly improving survival. These bioadhesives represent novel, inherently antibacterial materials for wound-filling applications.

Discussion of Lessons Learned from the First Quadruple Extremity Transplantation in the World: Comments and Concerns Regarding Quadruple Extremity Allotransplantation

Annals of Plastic Surgery. Sep, 2014  |  Pubmed ID: 25003409

Histomorphometric Evaluation of Ischemia-reperfusion Injury and the Effect of Preservation Solutions Histidine-tryptophan-ketoglutarate and University of Wisconsin in Limb Transplantation

Transplantation. Oct, 2014  |  Pubmed ID: 25073033

The effect of cold ischemia (CI) in vascularized composite allotransplantation is unknown. We herein assess tissue-specific damage, acceptable CI time, and the effect of preservation solutions in a syngenic rat hindlimb transplant model.

Ancillary Procedures Necessary for Translational Research in Experimental Craniomaxillofacial Surgery

The Journal of Craniofacial Surgery. Nov, 2014  |  Pubmed ID: 25377964

Swine are often regarded as having analogous facial skeletons to humans and therefore serve as an ideal animal model for translational investigation. However, there is a dearth of literature describing the pertinent ancillary procedures required for craniomaxillofacial research. With this in mind, our objective was to evaluate all necessary procedures required for perioperative management and animal safety related to experimental craniomaxillofacial surgical procedures such as orthotopic, maxillofacial transplantation.

Crucial Role for Neuronal Nitric Oxide Synthase in Early Microcirculatory Derangement and Recipient Survival Following Murine Pancreas Transplantation

PloS One. 2014  |  Pubmed ID: 25389974

Aim of this study was to identify the nitric oxide synthase (NOS) isoform involved in early microcirculatory derangements following solid organ transplantation.

MEMS-based Handheld Fourier Domain Doppler Optical Coherence Tomography for Intraoperative Microvascular Anastomosis Imaging

PloS One. 2014  |  Pubmed ID: 25474742

To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT) imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.

Proteomics in Transplantation

Advances in Clinical Chemistry. 2014  |  Pubmed ID: 25735863

Proteomics and biochemical profiling have emerged as exciting and powerful tools in clinical biomarker research. In the field of transplantation, proteomics aims not only at developing noninvasive means for immune monitoring but also to gain mechanistic insights into the pathophysiology of the alloimmune response and hence defining new therapeutic targets. This chapter provides an overview of proteomic biomarker-driven approaches and its underlying concepts and discusses the advantages, clinical implications, challenges, and limitations of this novel modality as it relates to solid organ transplantation.

Abstract 9: Selectively Permeable Nanofiber Constructs to Prevent Inflammatory Scarring and Enhance Nerve Regeneration in Peripheral Nerve Injury

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942120

Abstract 11: the Role of Donor Antigen Persistance in Maintaining Immune Tolerance to a Vascularized Composite Allograft

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942122

Abstract 102: Inflammatory Mediators Modulate Alloreactive T Cell Susceptibility to Immune-regulation in Reconstructive Transplantation

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942213

Abstract 105: a Non-suture Cuff Technique for Lymph-vein Anastomosis in a Rat Model

Plastic and Reconstructive Surgery. Mar, 2014  |  Pubmed ID: 25942216

The Role of Lipocalin-2 in Liver Regeneration

Liver International : Official Journal of the International Association for the Study of the Liver. Apr, 2015  |  Pubmed ID: 25040147

Various immune mediators such as interleukin-6 (IL-6) have been implicated in the process of liver regeneration. Lipocalin-2 (LCN2) has been recently characterized as a prototypic immune mediator produced by various cell types being involved mainly in host defence. In addition, numerous studies have demonstrated its clinical value as a biomarker. This study aimed at defining the role of LCN2 in liver regeneration.

Functional Abdominal Wall Reconstruction Using an Innervated Abdominal Wall Vascularized Composite Tissue Allograft: a Cadaveric Study and Review of the Literature

Journal of Reconstructive Microsurgery. Jan, 2015  |  Pubmed ID: 25184615

Large, composite abdominal wall defects represent complex problems requiring a multidisciplinary approach for reconstruction. Abdominal wall vascularized composite allotransplantation (AW-VCA) has been successfully performed in 21 patients, already receiving solid organ transplants, to provide immediate abdominal closure. The current study aims to establish a novel anatomic model for AW-VCA that retains motor and sensory function in an effort to preserve form and function while preventing complications.

Hand and Upper Extremity Transplantation: an Update of Outcomes in the Worldwide Experience

Plastic and Reconstructive Surgery. Feb, 2015  |  Pubmed ID: 25401735

Hand/upper extremity transplantation is the most common form of vascularized composite allotransplantation performed to date. An Update of worldwide outcomes is reported.

Stem Cell-based Approaches to Improve Nerve Regeneration: Potential Implications for Reconstructive Transplantation?

Archivum Immunologiae Et Therapiae Experimentalis. Feb, 2015  |  Pubmed ID: 25428664

Reconstructive transplantation has become a viable option to restore form and function after devastating tissue loss. Functional recovery is a key determinant of overall success and critically depends on the quality and pace of nerve regeneration. Several molecular and cell-based therapies have been postulated and tested in pre-clinical animal models to enhance nerve regeneration. Schwann cells remain the mainstay of research focus providing neurotrophic support and signaling cues for regenerating axons. Alternative cell sources such as mesenchymal stem cells and adipose-derived stromal cells have also been tested in pre-clinical animal models and in clinical trials due to their relative ease of harvest, rapid expansion in vitro, minimal immunogenicity, and capacity to integrate and survive within host tissues, thereby overcoming many of the challenges faced by culturing of human Schwann cells and nerve allografting. Induced pluripotent stem cell-derived Schwann cells are of particular interest since they can provide abundant, patient-specific autologous Schwann cells. The majority of experimental evidence on cell-based therapies, however, has been generated using stem cell-seeded nerve guides that were developed to enhance nerve regeneration across "gaps" in neural repair. Although primary end-to-end repair is the preferred method of neurorrhaphy in reconstructive transplantation, mechanistic studies elucidating the principles of cell-based therapies from nerve guidance conduits will form the foundation of further research employing stem cells in end-to-end repair of donor and recipient nerves. This review presents key components of nerve regeneration in reconstructive transplantation and highlights the pre-clinical studies that utilize stem cells to enhance nerve regeneration.

The Use of Luminex Assays to Measure Cytokines

The Journal of Investigative Dermatology. Apr, 2015  |  Pubmed ID: 25785953

Evaluation of Microvascular Anastomosis Using Real-time, Ultra-high-resolution, Fourier Domain Doppler Optical Coherence Tomography

Plastic and Reconstructive Surgery. Apr, 2015  |  Pubmed ID: 25811583

Evolution in microsurgical techniques and tools has paved the way for supermicrosurgical anastomoses, with vessel diameters often approaching below 0.8 mm in the clinical realm and even smaller (0.2 to 0.3 mm) in murine models. Several imaging and monitoring devices have been introduced for postoperative monitoring, but intraoperative guidance, assessment, and predictability have remained limited to binocular optical microscopy and the surgeon's experience. The authors present a high-resolution, real-time, three-dimensional imaging modality for intraoperative evaluation of luminal narrowing, thrombus formation, and flow alterations.

Exploring Cell-based Tolerance Strategies for Hand and Face Transplantation

Expert Review of Clinical Immunology. Nov, 2015  |  Pubmed ID: 26289376

Broader clinical application of reconstructive hand and face transplantation is hindered by the need for lifelong immunosuppression for allograft maintenance. In this review, we summarize various cell-based approaches to tolerance induction currently under investigation in both clinical and pre-clinical models to alleviate the need for chronic immunosuppression. These include strategies to induce mixed hematopoietic chimerism, therapy with T and B regulatory cells, regulatory macrophages, tolerogenic dendritic cells, and mesenchymal stem cells. The vascularized, intragraft bone components inherent to reconstructive transplants serve as a continuous source of donor-derived hematopoietic cells, and make hand and face transplants uniquely well suited for cell-based approaches to tolerance that may ultimately tilt the risk-benefit balance for these life-changing, but not life-saving, procedures.

Reconstruction of Large Abdominal Wall Defects Using Neurotized Vascular Composite Allografts

Plastic and Reconstructive Surgery. Oct, 2015  |  Pubmed ID: 26397250

Abdominal wall vascularized composite allotransplantation is the second most common form of vascularized composite allotransplantation. Sensory and functional recovery are expected in other forms but have never been demonstrated in abdominal wall vascularized composite allotransplantation. The authors hypothesize that coaptation of two thoracolumbar nerves will result in reinnervation of the alloflap and maintenance of the muscle component.

A Novel Method for the Repair of Critically Sized Bone Defects: Utilization of a Muscle Derived Stem Cell-Seeded Scaffold Augments Proliferation, Migration and Osteogenic Induction

Plastic and Reconstructive Surgery. Oct, 2015  |  Pubmed ID: 26397530

An Injectable Nanofiber-Hydrogel Composite with Interfacial Bonding for Soft Tissue Filling and Regeneration

Plastic and Reconstructive Surgery. Oct, 2015  |  Pubmed ID: 26397687

Optimal Murine Cranial Defect Reconstruction Utilizing a Novel Collagen Scaffold and RhBMP2 with Analysis Utilizing Confocal Microscopy

Plastic and Reconstructive Surgery. Oct, 2015  |  Pubmed ID: 26397690

Preventing Allograft Rejection by Targeting Immune Metabolism

Cell Reports. Oct, 2015  |  Pubmed ID: 26489460

Upon antigen recognition and co-stimulation, T lymphocytes upregulate the metabolic machinery necessary to proliferate and sustain effector function. This metabolic reprogramming in T cells regulates T cell activation and differentiation but is not just a consequence of antigen recognition. Although such metabolic reprogramming promotes the differentiation and function of T effector cells, the differentiation of regulatory T cells employs different metabolic reprogramming. Therefore, we hypothesized that inhibition of glycolysis and glutamine metabolism might prevent graft rejection by inhibiting effector generation and function and promoting regulatory T cell generation. We devised an anti-rejection regimen involving the glycolytic inhibitor 2-deoxyglucose (2-DG), the anti-type II diabetes drug metformin, and the inhibitor of glutamine metabolism 6-diazo-5-oxo-L-norleucine (DON). Using this triple-drug regimen, we were able to prevent or delay graft rejection in fully mismatched skin and heart allograft transplantation models.

Cardiac Arrest Disrupts Caspase-1 and Patterns of Inflammatory Mediators Differently in Skin and Muscle Following Localized Tissue Injury in Rats: Insights from Data-Driven Modeling

Frontiers in Immunology. 2015  |  Pubmed ID: 26635801

Trauma often cooccurs with cardiac arrest and hemorrhagic shock. Skin and muscle injuries often lead to significant inflammation in the affected tissue. The primary mechanism by which inflammation is initiated, sustained, and terminated is cytokine-mediated immune signaling, but this signaling can be altered by cardiac arrest. The complexity and context sensitivity of immune signaling in general has stymied a clear understanding of these signaling dynamics.

A Multiphase Transitioning Peptide Hydrogel for Suturing Ultrasmall Vessels

Nature Nanotechnology. Jan, 2016  |  Pubmed ID: 26524396

Many surgeries are complicated by the need to anastomose, or reconnect, micrometre-scale vessels. Although suturing remains the gold standard for anastomosing vessels, it is difficult to place sutures correctly through collapsed lumen, making the procedure prone to failure. Here, we report a multiphase transitioning peptide hydrogel that can be injected into the lumen of vessels to facilitate suturing. The peptide, which contains a photocaged glutamic acid, forms a solid-like gel in a syringe and can be shear-thin delivered to the lumen of collapsed vessels (where it distends the vessel) and the space between two vessels (where it is used to approximate the vessel ends). Suturing is performed directly through the gel. Light is used to initiate the final gel-sol phase transition that disrupts the hydrogel network, allowing the gel to be removed and blood flow to resume. This gel adds a new tool to the armamentarium for micro- and supermicrosurgical procedures.

Growth Hormone Therapy Accelerates Axonal Regeneration, Promotes Motor Reinnervation, and Reduces Muscle Atrophy Following Peripheral Nerve Injury

Plastic and Reconstructive Surgery. Jun, 2016  |  Pubmed ID: 26890510

Therapies to improve outcomes following peripheral nerve injury are lacking. Prolonged denervation of muscle and Schwann cells contributes to poor outcomes. In this study, the authors assess the effects of growth hormone therapy on axonal regeneration, Schwann cell and muscle maintenance, and end-organ reinnervation in rats.

Reply: Reconstruction of Large Abdominal Wall Defects Using Neurotized Vascular Composite Allografts

Plastic and Reconstructive Surgery. Jul, 2016  |  Pubmed ID: 27002563

Therapeutic Augmentation of the Growth Hormone Axis to Improve Outcomes Following Peripheral Nerve Injury

Expert Opinion on Therapeutic Targets. Oct, 2016  |  Pubmed ID: 27192539

Peripheral nerve injuries often result in debilitating motor and sensory deficits. There are currently no therapeutic agents that are clinically available to enhance the regenerative process. Following surgical repair, axons often must regenerate long distances to reach and reinnervate distal targets. Progressive atrophy of denervated muscle and Schwann cells (SCs) prior to reinnervation contributes to poor outcomes. Growth hormone (GH)-based therapies have the potential to accelerate axonal regeneration while at the same time limiting atrophy of muscle and the distal regenerative pathway prior to reinnervation.

Ex Vivo Model of Human Penile Transplantation and Rejection: Implications for Erectile Tissue Physiology

European Urology. Jul, 2016  |  Pubmed ID: 27432525

Penile transplantation is a potential treatment option for severe penile tissue loss. Models of human penile rejection are lacking.

Ischemia/reperfusion Injury in Vascularized Tissue Allotransplantation: Tissue Damage and Clinical Relevance

Current Opinion in Organ Transplantation. Oct, 2016  |  Pubmed ID: 27495915

Ischemia and reperfusion injury (IRI) in vascularized tissue allotransplantation (VCA) remain largely undefined. Because VCA is comprised of different tissues, the sensitivity towards IRI may not be uniform. We, herein, attempt to address mechanistic aspects of IRI in VCA and provide a summary on potential technologies and targets for amelioration or treatment of IRI in this novel field.

Mesenchymal Stem Cells Enhance Nerve Regeneration in a Rat Sciatic Nerve Repair and Hindlimb Transplant Model

Scientific Reports. Aug, 2016  |  Pubmed ID: 27510321

This study investigates the efficacy of local and intravenous mesenchymal stem cell (MSC) administration to augment neuroregeneration in both a sciatic nerve cut-and-repair and rat hindlimb transplant model. Bone marrow-derived MSCs were harvested and purified from Brown-Norway (BN) rats. Sciatic nerve transections and repairs were performed in three groups of Lewis (LEW) rats: negative controls (n = 4), local MSCs (epineural) injection (n = 4), and systemic MSCs (intravenous) injection (n = 4). Syngeneic (LEW-LEW) (n = 4) and allogeneic (BN-LEW) (n = 4) hindlimb transplants were performed and assessed for neuroregeneration after local or systemic MSC treatment. Rats undergoing sciatic nerve cut-and-repair and treated with either local or systemic injection of MSCs had significant improvement in the speed of recovery of compound muscle action potential amplitudes and axon counts when compared with negative controls. Similarly, rats undergoing allogeneic hindlimb transplants treated with local injection of MSCs exhibited significantly increased axon counts. Similarly, systemic MSC treatment resulted in improved nerve regeneration following allogeneic hindlimb transplants. Systemic administration had a more pronounced effect on electromotor recovery while local injection was more effective at increasing fiber counts, suggesting different targets of action. Local and systemic MSC injections significantly improve the pace and degree of nerve regeneration after nerve injury and hindlimb transplantation.

Combining Theoretical and Experimental Techniques to Study Murine Heart Transplant Rejection

Frontiers in Immunology. 2016  |  Pubmed ID: 27872621

The quality of life of organ transplant recipients is compromised by complications associated with life-long immunosuppression, such as hypertension, diabetes, opportunistic infections, and cancer. Moreover, the absence of established tolerance to the transplanted tissues causes limited long-term graft survival rates. Thus, there is a great medical need to understand the complex immune system interactions that lead to transplant rejection so that novel and effective strategies of intervention that redirect the system toward transplant acceptance (while preserving overall immune competence) can be identified. This study implements a systems biology approach in which an experimentally based mathematical model is used to predict how alterations in the immune response influence the rejection of mouse heart transplants. Five stages of conventional mouse heart transplantation are modeled using a system of 13 ordinary differential equations that tracks populations of both innate and adaptive immunity as well as proxies for pro- and anti-inflammatory factors within the graft and a representative draining lymph node. The model correctly reproduces known experimental outcomes, such as indefinite survival of the graft in the absence of CD4(+) T cells and quick rejection in the absence of CD8(+) T cells. The model predicts that decreasing the translocation rate of effector cells from the lymph node to the graft delays transplant rejection. Increasing the starting number of quiescent regulatory T cells in the model yields a significant but somewhat limited protective effect on graft survival. Surprisingly, the model shows that a delayed appearance of alloreactive T cells has an impact on graft survival that does not correlate linearly with the time delay. This computational model represents one of the first comprehensive approaches toward simulating the many interacting components of the immune system. Despite some limitations, the model provides important suggestions of experimental investigations that could improve the understanding of rejection. Overall, the systems biology approach used here is a first step in predicting treatments and interventions that can induce transplant tolerance while preserving the capacity of the immune system to protect against legitimate pathogens.

Impaired Endothelial Nitric Oxide Synthase Homodimer Formation Triggers Development of Transplant Vasculopathy - Insights from a Murine Aortic Transplantation Model

Scientific Reports. Nov, 2016  |  Pubmed ID: 27883078

Transplant vasculopathy (TV) represents a major obstacle to long-term graft survival and correlates with severity of ischemia reperfusion injury (IRI). Donor administration of the nitric oxide synthases (NOS) co-factor tetrahydrobiopterin has been shown to prevent IRI. Herein, we analysed whether tetrahydrobiopterin is also involved in TV development. Using a fully allogeneic mismatched (BALB/c to C57BL/6) murine aortic transplantation model grafts subjected to long cold ischemia time developed severe TV with intimal hyperplasia (α-smooth muscle actin positive cells in the neointima) and endothelial activation (increased P-selectin expression). Donor pretreatment with tetrahydrobiopterin significantly minimised these changes resulting in only marginal TV development. Severe TV observed in the non-treated group was associated with increased protein oxidation and increased occurrence of endothelial NOS monomers in the aortic grafts already during graft procurement. Tetrahydrobiopterin supplementation of the donor prevented all these early oxidative changes in the graft. Non-treated allogeneic grafts without cold ischemia time and syngeneic grafts did not develop any TV. We identified early protein oxidation and impaired endothelial NOS homodimer formation as plausible mechanistic explanation for the crucial role of IRI in triggering TV in transplanted aortic grafts. Therefore, targeting endothelial NOS in the donor represents a promising strategy to minimise TV.

Nasal Unit Transplantation: A Cadaveric Anatomical Feasibility Study

Journal of Reconstructive Microsurgery. Dec, 2016  |  Pubmed ID: 28024304

Background The science and technical acumen in the field of vascularized composite allotransplantation has progressed rapidly over the past 15 years, and transplantation of specialized units of the face, such as the nose, appears possible. No study to date has evaluated the technical feasibility of isolated nasal unit transplantation (NUT). In this study, we explore the anatomy and technical specifics of NUT. Methods In this study, four fresh cadaver heads were studied. Bilateral vascular pedicle dissections were performed in each cadaver. The facial artery was cannulated and injected with food dye under physiologic pressure in two cadavers, and with lead oxide mixture in two cadavers to evaluate perfusion territories supplied by each vascular pedicle. Results The facial artery and vein were found to be adequate pedicles for NUT. Divergent courses of the vein and artery were consistently identified, which made for a bulky pedicle with necessary inclusion of large amounts of subcutaneous tissue. In all cases, the artery remained superficial, while the vein coursed in a deeper plane, and demonstrated consistent anastomoses with the superior transverse orbital arcade. While zinc oxide injection of the facial artery demonstrated filling of the nasal vasculature across the midline, dye perfusion studies suggested that unilateral arterial inflow may be insufficient to perfuse contralateral NUT components. Discrepancies in these two studies underscore the limitations of nondynamic assessment of nutritive perfusion. Conclusion NUT based on the facial artery and facial vein is technically feasible. Angiosome evaluation suggests that bilateral pedicle anastomoses may be required to ensure optimal perfusion.

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