Translate this page to:
In JoVE (1)
Other Publications (40)
- Proceedings of the National Academy of Sciences of the United States of America
- Molecular Therapy : the Journal of the American Society of Gene Therapy
- American Journal of Physiology. Lung Cellular and Molecular Physiology
- Experimental Neurology
- The American Journal of Pathology
- FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology
- Progress in Cardiovascular Diseases
- Clinics in Laboratory Medicine
- Circulation Research
- Growth Hormone & IGF Research : Official Journal of the Growth Hormone Research Society and the International IGF Research Society
- The Journal of Trauma
- Current Opinion in Investigational Drugs (London, England : 2000)
- The Journal of Trauma
- The American Journal of Pathology
- Proceedings of the National Academy of Sciences of the United States of America
- Cancer Research
- The Journal of Trauma
- Biomechanics and Modeling in Mechanobiology
- The Journal of Surgical Research
- The Journal of Trauma
- International Journal of Experimental Pathology
- The Journal of Trauma
- The American Journal of Pathology
- The Journal of Trauma
- The Journal of Biological Chemistry
- PloS One
- Cancer Microenvironment : Official Journal of the International Cancer Microenvironment Society
- Cardiovascular Pathology : the Official Journal of the Society for Cardiovascular Pathology
- Molecular Cancer Research : MCR
- Transfusion Medicine Reviews
- Cell Transplantation
- Vitamins and Hormones
- Wound Repair and Regeneration : Official Publication of the Wound Healing Society [and] the European Tissue Repair Society
- American Journal of Physiology. Endocrinology and Metabolism
This translation into Dutch was automatically generated.
English Version | Other Languages
Articles by Pampee P. Young in JoVE
De polyvinylalcohol Sponge Model Implantatie
Desirae L. Deskins1,2, Shidrokh Ardestani1,2, Pampee P. Young1,2,3
1Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, 2The Department of Veterans Affairs Medical Center, 3Internal Medicine, Vanderbilt University School of Medicine
Een handig hulpmiddel om de effecten van drugs, groeifactoren, en / of gemanipuleerde cellen in een diermodel van wondheling te analyseren wordt beschreven. Deze techniek maakt gebruik van de eigenschappen van een polyvinyl alcohol (PVA) spons leveren en bevatten de gewenste behandeling en een platform worden uitgesneden en geanalyseerd voorzien.
Other articles by Pampee P. Young on PubMed
VEGF Increases Engraftment of Bone Marrow-derived Endothelial Progenitor Cells (EPCs) into Vasculature of Newborn Murine Recipients
Proceedings of the National Academy of Sciences of the United States of America. Sep, 2002 | Pubmed ID: 12195016
Recent evidence suggests that bone marrow-derived angioblasts or endothelial progenitor cells circulate in peripheral blood and can incorporate at sites of pathologic neovascularization or during the ovarian cycle. However, the incorporation of endothelial progenitor cells into vessels of nonischemic tissues in adult animals has not been observed. We hypothesized that the vascular microenvironment differs between newborn and adult animals, and that donor endothelial cell progenitors would engraft in rapidly growing normal tissues during the neonatal period. After nonablative administration of bone marrow cells either at birth or at 4 weeks of age, donor-derived endothelial cells were found only in the neovasculature of the newborn recipients. Both the incorporation of donor endothelial cells into the newborn neovasculature as well as tissue vascularity were significantly increased by coadministering vascular endothelial growth factor with bone marrow cells. These findings suggest that bone marrow-derived endothelial progenitor cells can contribute to neovascularization during the newborn period and are responsive to vascular endothelial growth factor.
Molecular Therapy : the Journal of the American Society of Gene Therapy. Jan, 2003 | Pubmed ID: 12573618
Lymphocyte-directed gene transfer has been proposed as potential therapy to treat certain congenital immunological deficiencies as well as other genetic diseases such as lysosomal storage diseases (LSDs). To understand better the extent to which adoptively transferred peripheral T lymphocytes (PTLs) are able to ameliorate LSDs we utilized the beta-glucuronidase-deficient mouse as a model system. PTLs (1 x 10(7)) isolated from the spleen of syngeneic mice overexpressing ( approximately 8-fold) human beta-glucuronidase (GUSB) were injected intravenously into young adult beta-glucuronidase-deficient mice without myeloablative conditioning. Using biochemical and histochemical assays, we were able to track the donor lymphocytes in vivo. Donor lymphocytes were detected in relatively high numbers in liver, spleen, small intestine, mesenteric lymph node, and thymus for at least 5 months, the last time point of analysis. Although liver and spleen had the highest total GUSB activity, histopathologic analysis demonstrated minimal to no correction of lysosomal distention at all time points studied. By contrast, we have shown in earlier studies that administration of similar numbers of macrophages reduced lysosomal storage in several organs, including liver and spleen. To understand this difference in efficacy, we compared the relative level of GUSB released into the medium by nonactivated and activated PTLs as well as by macrophages. Macrophages released >50-fold excess enzyme compared to either activated or nonactivated PTLs. These data suggest that a LSD can be more effectively treated by directing a gene therapy approach to a hematopoietic lineage other than T lymphocytes.
Glucocorticoid Inhibition of SP-A Gene Expression in Lung Type II Cells is Mediated Via the TTF-1-binding Element
American Journal of Physiology. Lung Cellular and Molecular Physiology. Apr, 2004 | Pubmed ID: 14633512
Induction of surfactant protein-A (SP-A) gene expression in fetal lung type II cells by cAMP and IL-1 is mediated by increased binding of thyroid transcription factor-1 (TTF-1) and NF-B proteins p50 and p65 to the TTF-1-binding element (TBE) at -183 bp. In type II cell transfections, dexamethasone (Dex) markedly inhibits cAMP-induced expression of rabbit SP-A:human growth hormone (hGH) fusion genes containing as little as 300 bp of the SP-A 5'-flanking sequence. Dex inhibition is blocked by RU-486, suggesting a role of the glucocorticoid receptor (GR). The present study was undertaken to define the mechanisms for GR inhibition of SP-A expression. Cotransfection of primary cultures of type II cells with a GR expression vector abrogated cAMP induction of SP-A promoter activity while, at the same time, causing a 60-fold induction of cotransfected mouse mammary tumor virus (MMTV) promoter. In lung cells transfected with a fusion gene containing three TBEs fused to the basal SP-A promoter, Dex prevented the stimulatory effect of IL-1 on TTF-1 induction of SP-A promoter activity, suggesting that the GR inhibits SP-A promoter activity through the TBE. In gel shift assays using nuclear extracts from human fetal type II cells cultured in the absence or presence of cAMP, Dex markedly reduced binding of nuclear proteins to the TBE and blocked the stimulatory effect of cAMP on TBE-binding activity. Our finding that Dex increased expression of the NF-kappaB inhibitory partner IkappaB-alpha suggests that the decrease in TBE-binding activity may be caused, in part, by GR inhibition of NF-kappaB interaction with this site.
Autoantibody Formation After Alloimmunization: Are Blood Transfusions a Risk Factor for Autoimmune Hemolytic Anemia?
Transfusion. Jan, 2004 | Pubmed ID: 14692969
The development of RBC autoantibodies resulting from or associated with allogeneic blood transfusions (i.e., RBC autoimmunization) is not a well-recognized complication of RBC transfusions.
VEGF Disrupts the Neonatal Blood-brain Barrier and Increases Life Span After Non-ablative BMT in a Murine Model of Congenital Neurodegeneration Caused by a Lysosomal Enzyme Deficiency
Experimental Neurology. Jul, 2004 | Pubmed ID: 15191807
The course of certain congenital neurodegenerative diseases like lysosomal storage diseases (LSDs) begins shortly after birth and can progress quickly. Ideally, therapeutic interventions for LSDs, which include bone marrow transplantation (BMT), recombinant enzyme replacement, or systemic viral-mediated gene therapy, should be initiated at birth. However, the blood-brain barrier (BBB) remains an obstacle to effective therapy even when these strategies are initiated at birth. We studied whether VEGF, an endothelial cell mitogen and permeability factor, can open the BBB in newborn mice for therapeutic purposes. Intravenous (IV) administration of VEGF at birth increased BBB permeability within 2 h. The increased permeability persisted for at least 24 h, became undetectable 48 h after injection, and was restricted to newborns. Systemic VEGF treatment before BMT or administration of recombinant lentivirus resulted in increased numbers of both donor cells and virus-transduced cells, respectively, in the recipient brain. Administration of VEGF before BMT in newborn mice with a neurodegenerative LSD, globoid-cell leukodystrophy, resulted in a significant increase in life span compared to affected animals that were injected with saline before BMT.
Blood Donor White Blood Cell Reduction Filters As a Source of Human Peripheral Blood-derived Endothelial Progenitor Cells
Transfusion. Jan, 2005 | Pubmed ID: 15647014
Neovascularization in tumors, wounds, and sites of ischemic injury occurs by both angiogenesis (proliferation from existing vessels) and by vasculogenesis (differentiation into endothelial cells from circulating endothelial progenitor cells [EPCs]). EPCs can be obtained from marrow, from cord blood, or by ex vivo expansion of human peripheral blood (PB). The ease of obtaining human PB EPCs has led many recent studies to utilize PB EPCs. The ability to obtain large numbers of PB EPCs would greatly facilitate characterization to further our understanding of EPC biology and their application in cellular gene therapy.
Enrichment of Genes in the Aortic Intima That Are Associated with Stratified Epithelium: Implications of Underlying Biomechanical and Barrier Properties of the Arterial Intima
Circulation. May, 2005 | Pubmed ID: 15867175
Arteries and veins are exposed to different pressures and are easily distinguished by morphology. Although several recent studies have focused on differential gene expression between the arterial and venous endothelium, the molecular distinctions that give rise to the dramatic structural distinctions between arteries and veins, such as in the organization of the intima, are not known.
The Origin and in Vivo Significance of Murine and Human Culture-expanded Endothelial Progenitor Cells
The American Journal of Pathology. May, 2006 | Pubmed ID: 16651636
In adults highly purified populations of early hematopoietic progenitors or cells derived from ex vivo expanded unmobilized human peripheral blood mononuclear cells contribute to new blood vessel formation. However, the source of these culture-expanded endothelial progenitor cells (CE-EPCs) remains controversial. We demonstrate that ex vivo expansion of unmobilized human peripheral blood generated CE-EPCs with similar numbers, kinetics, and antigen expression profile as compared to plating unfractionated CD34(+)/lin(-)-enriched bone marrow mononuclear cells. Both CE-EPC populations uniformly co-expressed myeloid and endothelial markers, suggesting that peripheral blood progenitor enumeration does not correlate with the numbers of early outgrowth CE-EPCs. Using purified myeloid subpopulations obtained from mice harboring the lacZ transgene driven by an endothelial-specific promoter, we showed that the immature myeloid lineage marker CD31(+) cells generated CE-EPCs with fourfold greater frequency than mature myeloid populations. Biphenotypic cells co-expressing myeloid/endothelial antigens were not detected in circulating human or murine peripheral blood or bone marrow but were associated with murine tumors. Unlike CE-EPCs, CD14(+) leukocytes admixed within tumors did not generate vWF-positive blood vessels during a similarly defined period of tumor growth, but some leukocytes up-regulated the endothelial marker VE-cadherin. Taken together, the data suggest that the local neovascular microenvironment may facilitate vasculogenesis by promoting endothelial differentiation and that CE-EPCs may accelerate such vasculo-genesis.
VEGF and PlGF Promote Adult Vasculogenesis by Enhancing EPC Recruitment and Vessel Formation at the Site of Tumor Neovascularization
FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology. Jul, 2006 | Pubmed ID: 16754748
There are growing data to suggest that tissue hypoxia represents a critical force that drives adult vasculogenesis. Vascular endothelial growth factor (VEGF) expression is dramatically up-regulated by hypoxia and results in enhanced neovascularization. Although the role of VEGF in angiogenesis has been well characterized, its role in adult vasculogenesis remains poorly understood. We used two distinct murine bone marrow transplantation (BMT) models to demonstrate that increased VEGF levels at the site of tumor growth promoted vasculogenesis in vivo. This effect of VEGF was downstream of its effect to enhance either mobilization or survival of circulating endothelial progenitor cells (EPCs). Both VEGFR1 (flt1) and VEGFR2 (flk1) are expressed on culture expanded human EPCs. Previous studies suggest that the effect of VEGF on endothelial cell migration is primarily mediated via VEGFR2; however, VEGF-induced EPC migration in vitro was mediated by both receptors, suggesting that VEGF-VEGFR1 interactions in EPCs are distinct from differentiated endothelial cells. We used specific blocking antibodies to these receptors to demonstrate that VEGFR1 plays an important role in human EPC recruitment to tumors. These findings were further supported by our finding that tumor-associated placental growth factor (PlGF), a VEGFR1-specific agonist, increased tumor vasculogenesis in a murine BMT model. We further showed that both VEGF receptors were necessary for the formation of functional vessels derived from exogenously administered human ex vivo expanded EPCs. Our data suggest local VEGF and/or PlGF expression promote vasculogenesis; VEGF plays a role in EPC recruitment and subsequent formation of functional vessels.
Progress in Cardiovascular Diseases. May-Jun, 2007 | Pubmed ID: 17498522
Recent studies indicate that portions of ischemic and tumor neovasculature are derived by neovasculogenesis, whereby bone marrow (BM)-derived circulating endothelial progenitor cells (EPCs) home to sites of regenerative or malignant growth and contribute to blood vessel formation. Recent data from animal models suggest that a variety of cell types, including unfractionated BM mononuclear cells and those obtained by ex vivo expansion of human peripheral blood or enriched progenitors, can function as EPCs to promote tissue vasculogenesis, regeneration, and repair when introduced in vivo. The promising preclinical results have led to several human clinical trials using BM as a potential source of EPCs in cardiac repair as well as ongoing basic research on using EPCs in tissue engineering or as cell therapy to target tumor growth.
Clinics in Laboratory Medicine. Jun, 2007 | Pubmed ID: 17556094
Laboratory medicine offers attractive opportunities for individuals who have MD and PhD degrees and advanced training in medicine and the underlying basic biomedical sciences, and these individuals have much to contribute to the field. The modern era of basic biomedical sciences has produced a wealth of genomic, postgenomic, and proteomic knowledge. As a bridge discipline, a major challenge and opportunity for laboratory medicine is to bring these advances to the diagnostic, prognostic, and therapeutic care of patients. The authors believe that, for many reasons, the field of laboratory medicine represents an excellent, although underrecognized, career choice for graduates of MD/PhD programs.
Adenosine Receptor-mediated Adhesion of Endothelial Progenitors to Cardiac Microvascular Endothelial Cells
Circulation Research. Feb, 2008 | Pubmed ID: 18032734
Intracoronary delivery of endothelial progenitor cells (EPCs) is an emerging concept for the treatment of cardiovascular disease. Enhancement of EPC adhesion to vascular endothelium could improve cell retention within targeted organs. Because extracellular adenosine is elevated at sites of ischemia and stimulates neovascularization, we examined the potential role of adenosine in augmenting EPC retention to cardiac microvascular endothelium. Stimulation of adenosine receptors in murine embryonic EPCs (eEPCs) and cardiac endothelial cells (cECs) rapidly, within minutes, increased eEPC adhesion to cECs under static and flow conditions. Similarly, adhesion of human adult culture-expanded EPCs to human cECs was increased by stimulation of adenosine receptors. Furthermore, adenosine increased eEPC retention in isolated mouse hearts perfused with eEPCs. We determined that eEPCs and cECs preferentially express functional A1 and A2B adenosine receptor subtypes, respectively, and that both subtypes are involved in the regulation of eEPC adhesion to cECs. We documented that the interaction between P-selectin and its ligand (P-selectin glycoprotein ligand-1) plays a role in adenosine-dependent eEPC adhesion to cECs and that stimulation of adenosine receptors in cECs induces rapid cell surface expression of P-selectin. Our results suggest a role for adenosine in vasculogenesis and its potential use to stimulate engraftment in cell-based therapies.
Growth Hormone & IGF Research : Official Journal of the Growth Hormone Research Society and the International IGF Research Society. Jun, 2008 | Pubmed ID: 18166495
Endothelial progenitor cells (EPCs) mobilize from the bone marrow secondary to a stimulus and home to sites of injury, where they differentiate into endothelial cells and contribute to the repair of damaged vasculature. We hypothesized that growth hormone (GH) administration would increase the number of circulating EPCs in adults and thereby represent a mechanism to enhance vascular health.
Damage Control Hematology: the Impact of a Trauma Exsanguination Protocol on Survival and Blood Product Utilization
The Journal of Trauma. May, 2008 | Pubmed ID: 18469638
The importance of early and aggressive management of trauma- related coagulopathy remains poorly understood. We hypothesized that a trauma exsanguination protocol (TEP) that systematically provides specified numbers and types of blood components immediately upon initiation of resuscitation would improve survival and reduce overall blood product consumption among the most severely injured patients.
The Effects of Growth Hormone and Insulin-like Growth Factor-1 on the Aging Cardiovascular System and Its Progenitor Cells
Current Opinion in Investigational Drugs (London, England : 2000). Sep, 2008 | Pubmed ID: 18729005
Aging is a major risk factor for the development of cardiovascular disease. Aging is also associated with a decline in the growth hormone (GH) and insulin-like growth factor-1 (IGF-1) axis. This axis impacts endothelial and vascular smooth muscle cell biology, as well as cardiac function. The number of endothelial progenitor cells (EPCs) also decreases with age and is emerging as a surrogate measurement of vascular senescence. Studies suggest that EPCs impact vascular health by modulating vascular repair and function. Current evidence demonstrates that EPC number and function is restored with a GH-mediated increase in serum IGF-1. Modulation of the GH and IGF-1 system may therefore provide a useful therapy in the prevention of age-associated changes in the cardiovascular system and in future regenerative cell-based therapies.
Optimizing Outcomes in Damage Control Resuscitation: Identifying Blood Product Ratios Associated with Improved Survival
The Journal of Trauma. Sep, 2008 | Pubmed ID: 18784564
Despite recent attention and impressive results with damage control resuscitation, the appropriate ratio of blood products to be transfused has yet to be defined. The purpose of this study was to evaluate whether suggested blood product ratios yield superior survival rates.
Regulation of the Atheroma-enriched Protein, SPRR3, in Vascular Smooth Muscle Cells Through Cyclic Strain is Dependent on Integrin Alpha1beta1/collagen Interaction
The American Journal of Pathology. Nov, 2008 | Pubmed ID: 18832573
Atherosclerotic plaques express high levels of small proline-rich repeat protein (SPRR3), a previously characterized component of the cornified cell envelope of stratified epithelia, where it is believed to play a role in cellular adaptation to biomechanical stress. We investigated the physiological signals and underlying mechanism(s) that regulate atheroma-enriched SPRR3 expression in vascular smooth muscle cells (VSMCs). We showed that SPRR3 is expressed by VSMCs in both human and mouse atheromas. In cultured arterial VSMCs, mechanical cyclic strain, but neither shear stress nor lipid loading induced SPRR3 expression. Furthermore, this upregulation of SPRR3 expression was dependent on VSMC adherence to type I collagen. To link the mechanoregulation of SPRR3 to specific collagen/integrin interactions, we used blocking antibodies against either integrin alpha1 or alpha2 subunits and VSMCs from mice that lack specific collagen receptors. Our results showed a dependence on the alpha1beta1 integrin for SPRR3 expression induced by cyclic strain. Furthermore, we showed that integrin alpha1 but not alpha2 subunits were expressed on VSMCs within mouse lesions but not in normal arteries. Therefore, we identified the enrichment of the mechanical strain-regulated protein SPRR3 in VSMCs of both human and mouse atherosclerotic lesions whose expression is dependent on the collagen-binding integrin alpha1beta1 on VSMCs. These data suggest that SPRR3 may play a role in VSMC adaptation to local biomechanical stress within the plaque microenvironment.
The Wnt Modulator SFRP2 Enhances Mesenchymal Stem Cell Engraftment, Granulation Tissue Formation and Myocardial Repair
Proceedings of the National Academy of Sciences of the United States of America. Nov, 2008 | Pubmed ID: 19017790
Cell-based therapies, using multipotent mesenchymal stem cells (MSCs) for organ regeneration, are being pursued for cardiac disease, orthopedic injuries and biomaterial fabrication. The molecular pathways that regulate MSC-mediated regeneration or enhance their therapeutic efficacy are, however, poorly understood. We compared MSCs isolated from MRL/MpJ mice, known to demonstrate enhanced regenerative capacity, to those from C57BL/6 (WT) mice. Compared with WT-MSCs, MRL-MSCs demonstrated increased proliferation, in vivo engraftment, experimental granulation tissue reconstitution, and tissue vascularity in a murine model of repair stimulation. The MRL-MSCs also reduced infarct size and improved function in a murine myocardial infarct model compared with WT-MSCs. Genomic and functional analysis indicated a downregulation of the canonical Wnt pathway in MRL-MSCs characterized by significant up-regulation of specific secreted frizzled-related proteins (sFRPs). Specific knockdown of sFRP2 by shRNA in MRL-MSCs decreased their proliferation and their engraftment in and the vascular density of MRL-MSC-generated experimental granulation tissue. These results led us to generate WT-MSCs overexpressing sFRP2 (sFRP2-MSCs) by retroviral transduction. sFRP2-MSCs maintained their ability for multilineage differentiation in vitro and, when implanted in vivo, recapitulated the MRL phenotype. Peri-infarct intramyocardial injection of sFRP2-MSCs resulted in enhanced engraftment, vascular density, reduced infarct size, and increased cardiac function after myocardial injury in mice. These findings implicate sFRP2 as a key molecule for the biogenesis of a superior regenerative phenotype in MSCs.
Low Levels of Tumor Necrosis Factor Alpha Increase Tumor Growth by Inducing an Endothelial Phenotype of Monocytes Recruited to the Tumor Site
Cancer Research. Jan, 2009 | Pubmed ID: 19118019
Microenvironmental cues instruct infiltrating tumor-associated myeloid cells to drive malignant progression. A subpopulation of tumor-associated myeloid cells coexpressing endothelial and myeloid markers, although rare in peripheral blood, are primarily associated with tumors where they enhance tumor growth and angiogenesis. These biphenotypic vascular leukocytes result from the endothelial differentiation of myeloid progenitors, a process regulated by tumor necrosis factor (TNF)alpha in vitro. An in vivo increase in tumor-derived TNFalpha expression promoted tumor growth and vascularity of mouse melanoma, lung cancer, and mammary tumors. Notably, tumor growth was accompanied by a significant increase in myeloid/endothelial biphenotypic populations. TNFalpha-associated tumor growth, vascularity, and generation of tumor vascular leukocytes in mouse melanoma tumors were dependent on intact host TNFalpha receptors. Importantly, TNFalpha-expressing tumors did not exhibit increased inflammation over control tumors, suggesting a unique action related to myeloid to endothelial differentiation. Our studies suggest that TNFalpha constitutes a tumor microenvironment signal that biases recruited monocytes toward a proangiogenic/provasculogenic myeloid/endothelial phenotype.
Predefined Massive Transfusion Protocols Are Associated with a Reduction in Organ Failure and Postinjury Complications
The Journal of Trauma. Jan, 2009 | Pubmed ID: 19131804
Massive transfusion (MT) protocols have been shown to improve survival in severely injured patients. However, others have noted that these higher fresh frozen plasma (FFP):red blood cell (RBC) ratios are associated with increased risk of organ failure. The purpose of this study was to determine whether MT protocols are associated with increased organ failure and complications.
Biomechanics and Modeling in Mechanobiology. Aug, 2009 | Pubmed ID: 19308472
In previous work, a new assay was realized for determining soft-tissue mechanical properties. The method, named the model-gel-tissue (MGT) assay, couples material testing with a finite element model built from a micro-CT image acquisition of a gel-embedded tissue specimen to determine its mechanical properties. Given recent reports demonstrating that increased stromal collagen promotes mammary tumor initiation and proliferation, in this paper, the MGT assay is used to evaluate the modulus of murine mammary tumors and is subsequently correlated quantitatively to type I collagen content. In addition, preliminary testing of the assay sensitivity with respect to gel-volume to tissue-mass ratio is reported here. The results demonstrate a strong linear correlation between tumor mechanical properties and collagen content (R (2) = 0.9462). This result is important because mechanical stiffness as provided by the MGT assay is very similar to parameters under clinical investigation using elastographic imaging techniques. The sensitivity tests indicated that an approximate gel-volume to tissue-mass ratio threshold of 16.5 ml g(-1) is needed for successful analysis. This is an important result in that it presents guideline constraints for conducting this analysis.
The Journal of Surgical Research. Dec, 2009 | Pubmed ID: 19765727
Large-volume blood transfusions have been implicated in the development of hyperkalemia. The purpose of the current study was to determine whether critically injured patients receiving massive transfusions are at an increased risk of hyperkalemia.
Room for (performance) Improvement: Provider-related Factors Associated with Poor Outcomes in Massive Transfusion
The Journal of Trauma. Nov, 2009 | Pubmed ID: 19901661
Massive transfusion (MT) protocols improve survival in patients with exsanguinating hemorrhage. Both the increased plasma to red blood cells (RBC) and platelets to RBC ratios, and the "protocolization" of product delivery seem to be critical components of the reduction in mortality. The purpose of this study was to identify the incidence and impact of MT protocol noncompliance and to intervene in provider-related events associated with poor compliance and outcomes.
International Journal of Experimental Pathology. Aug, 2010 | Pubmed ID: 20353421
A significant proportion of patients with osteogenic sarcoma die from lung metastasis within 5 years of diagnosis. Molecular signatures that predict pulmonary metastasis from primary osteogenic sarcoma and identify those patients at risk would be clinically useful as prognostic markers. Protein expression profiles of two clonally related murine osteogenic sarcoma cell lines with low (K12) and high (K7M2) metastatic potential were compared using two different proteomic technologies, two-dimensional difference gel electrophoresis and cell profiling by matrix-assisted laser desorption/ionization mass spectrometry. Interrogation of a molecular pathways network database suggested several additional candidate molecules that potentially predict metastatic potential of primary osteogenic sarcoma. Two such proteins, macrophage migration inhibitory factor and tumour necrosis factor were selected for further validation studies. Western blots confirmed increased expression of both cytokines in K7M2 cells compared to K12 cells. Levels of migration inhibitory factor and tumour necrosis factor were semi-quantitatively measured in human osteogenic sarcoma samples by immunohistochemistry and were correlated with clinicopathologic parameters and patient outcomes. Multivariate survival analysis demonstrated that tumour necrosis factor expression in chemotherapy naïve osteogenic sarcoma is an independent prognostic factor for overall and metastasis-free survival. No significant differences in adverse outcomes were observed based on macrophage migration inhibitory factor expression.
Emergency Department Blood Transfusion Predicts Early Massive Transfusion and Early Blood Component Requirement
Transfusion. Sep, 2010 | Pubmed ID: 20456707
The purpose of this study was to evaluate the ability of uncrossmatched transfusions in the emergency department (ED) to predict early (< 6 hr) massive transfusion (MT) of red blood cells (RBCs) and blood components.
Creation, Implementation, and Maturation of a Massive Transfusion Protocol for the Exsanguinating Trauma Patient
The Journal of Trauma. Jun, 2010 | Pubmed ID: 20539192
The majority of trauma patients (>90%) do not require any blood product transfusion and their mortality is <1%. However, 3% to 5% of civilian trauma patients will receive a massive transfusion (MT), defined as >10 units of packed red blood cells (PRBC) in 24 hours. In addition, more than 25% of these patients will arrive to emergency departments with evidence of trauma-associated coagulopathy. With this combination of massive blood loss and coagulopathy, it has become increasingly more common to transfuse early the trauma patients and with a combination of PRBC, plasma, and platelets. Given the inherent uncertainties common early in the care of patients with severe injuries, the efficient administration of massive amounts of PRBC and clotting factors tends to work best in a predefined, protocol driven system. Our purpose here is to (1) define the problem of massive hemorrhage and coagulopathy in the trauma patient, (2) identify which group of patients this type of protocol should be applied, (3) describe the extensive coordination required to implement this multispecialty MT protocol, (4) explain in detail how the MT was developed and implemented, and (5) emphasize the need for a robust performance improvement or quality improvement process to monitor the implementation of such a protocol and to help identify problems and deliver feedback in a "real-time" fashion. The successful implementation of such a complex process can only be accomplished in a multispecialty setting. Input and representation from departments of Trauma, Critical Care, Anesthesiology, Transfusion Medicine, and Emergency Medicine are necessary to successfully formulate (and implement) such a protocol. Once a protocol has been agreed upon, education of the entire nursing and physician staff is equally essential to the success of this effort. Once implemented, this process may lead to improved clinical outcomes and decreased overall blood utilization with extremely small wastage of vital blood products.
The American Journal of Pathology. Jul, 2010 | Pubmed ID: 20558573
Atherosclerosis, a chronic vascular disease, is the underlying cause of over half the deaths in the United States each year. Variations in local vascular hemodynamics predispose select sites in the vasculature to atherosclerosis, and the atherosclerotic lesions, in turn alter the biomechanical functioning of the local microenvironment, the consequences of which are not well understood on a molecular level. Further progress in the field of atherosclerosis will require an understanding of the relationship between biomechanics, the tissue microenvironment, and the cellular and molecular response to these factors. This review summarizes this field, particularly within the context of the vascular smooth muscle cell.
The Journal of Trauma. Jul, 2010 | Pubmed ID: 20622617
Several studies have described predictive models to identify trauma patients who require massive transfusion (MT). Early identification of lethal exsanguination may improve survival in this patient population. The purpose of the current study was to validate a simplified score to predict MT at multiple Level I trauma centers.
SFRP2 Suppression of Bone Morphogenic Protein (BMP) and Wnt Signaling Mediates Mesenchymal Stem Cell (MSC) Self-renewal Promoting Engraftment and Myocardial Repair
The Journal of Biological Chemistry. Nov, 2010 | Pubmed ID: 20826809
Transplantation of mesenchymal stem cells (MSCs) is a promising therapy for ischemic injury; however, inadequate survival of implanted cells in host tissue is a substantial impediment in the progress of cellular therapy. Secreted Frizzled-related protein 2 (sFRP2) has recently been highlighted as a key mediator of MSC-driven myocardial and wound repair. Notably, sFRP2 mediates significant enhancement of MSC engraftment in vivo. We hypothesized that sFRP2 improves MSC engraftment by modulating self-renewal through increasing stem cell survival and by inhibiting differentiation. In previous studies we demonstrated that sFRP2-expressing MSCs exhibited an increased proliferation rate. In the current study, we show that sFRP2 also decreased MSC apoptosis and inhibited both osteogenic and chondrogenic lineage commitment. sFRP2 activity occurred through the inhibition of both Wnt and bone morphogenic protein (BMP) signaling pathways. sFRP2-mediated inhibition of BMP signaling, as assessed by levels of pSMAD 1/5/8, was independent of its effects on the Wnt pathway. We further hypothesized that sFRP2 inhibition of MSC lineage commitment may reduce heterotopic osteogenic differentiation within the injured myocardium, a reported adverse side effect. Indeed, we found that sFRP2-MSC-treated hearts and wound tissue had less ectopic calcification. This work provides important new insight into the mechanisms by which sFRP2 increases MSC self-renewal leading to superior tissue engraftment and enhanced wound healing.
Pyrvinium, a Potent Small Molecule Wnt Inhibitor, Promotes Wound Repair and Post-MI Cardiac Remodeling
PloS One. 2010 | Pubmed ID: 21170416
Wnt signaling plays an important role in developmental and stem cell biology. To test the hypothesis that temporary inhibition of Wnt signaling will enhance granulation tissue and promote angiogenesis in tissue repair, we employed a recently characterized small molecule Wnt inhibitor. Pyrvinium is an FDA-approved drug that we identified as a Wnt inhibitor in a chemical screen for small molecules that stabilize β-catenin and inhibit Axin degradation. Our subsequent characterization of pyrvinium has revealed that its critical cellular target in the Wnt pathway is Casein Kinase 1α. Daily administration of pyrvinium directly into polyvinyl alcohol (PVA) sponges implanted subcutaneously in mice generated better organized and vascularized granulation tissue; this compound also increased the proliferative index of the tissue within the sponges. To evaluate its effect in myocardial repair, we induced a myocardial infarction (MI) by coronary artery ligation and administered a single intramyocardial dose of pyrvinium. Mice were evaluated by echocardiography at 7 and 30 days post-MI and treatment; post mortem hearts were evaluated by histology at 30 days. Pyrvinium reduced adverse cardiac remodeling demonstrated by decreased left ventricular internal diameter in diastole (LVIDD) as compared to a control compound. Increased Ki-67+ cells were observed in peri-infarct and distal myocardium of pyrvinium-treated animals. These results need to be further followed-up to determine if therapeutic inhibition of canonical Wnt may avert adverse remodeling after ischemic injury and its impact on myocardial repair and regeneration.
Myeloid Cells in Cancer Progression: Unique Subtypes and Their Roles in Tumor Growth, Vascularity, and Host Immune Suppression
Cancer Microenvironment : Official Journal of the International Cancer Microenvironment Society. 2010 | Pubmed ID: 21505557
Leukocytic infiltrates, particularly myeloid cells, can stimulate an anti-tumor immune response, but more often they stimulate tumor development, including promoting invasion, tumor growth, angiogenesis, and metastasis. Distinct myeloid phenotypes are being characterized that have been shown to promote tumor growth, angiogenesis, and metastasis. This review provides an overview of myeloid differentiation and spotlights specific pro-tumorogenic myeloid populations and their role in cancer progression. Efforts to characterize these pro-tumorogenic myeloid cell immunophenotypes may lead to novel targets for cancer therapy.
Biomechanical Stress Induces Novel Arterial Intima-enriched Genes: Implications for Vascular Adaptation to Stress
Cardiovascular Pathology : the Official Journal of the Society for Cardiovascular Pathology. Mar-Apr, 2010 | Pubmed ID: 19211270
The arterial vasculature is subjected to considerably greater biomechanical stress than the venous circulation. This is reflected in the difference in morphology between large arteries and veins, however little is known about the molecular differences that arise as a consequence of biomechanical stress. Previously, we identified a group of arterial intima-enriched (AIE) genes: sciellin, periplakin, SPRR3, envoplakin, galectin 7, and plakoglobin that are functionally related in that they contribute to the stress properties of stratified epithelium. We sought to test our hypothesis that these genes were regulated by biomechanical stress in vascular smooth muscle cells (VSMCs).
TNFalpha Accelerates Monocyte to Endothelial Transdifferentiation in Tumors by the Induction of Integrin Alpha5 Expression and Adhesion to Fibronectin
Molecular Cancer Research : MCR. Jun, 2011 | Pubmed ID: 21536688
Tumor-associated myeloid cells are believed to promote tumor development by stimulating tumor growth, angiogenesis, invasion, and metastasis. Tumor-associated myeloid cells that coexpress endothelial and myeloid markers represent a proangiogenic subpopulation known as vascular leukocytes. Recently, we and others had shown that tumor-derived TNFα promotes local tumor growth and vascularity. Our data suggested that tumor growth is in part due to TNFα-mediated increased numbers of tumor-associated vascular leukocytes (i.e., myeloid-endothelial biphenotypic cells). The work detailed herein explored the mechanism by which TNFα mediates endothelial differentiation of myeloid cells. Our studies showed that fibronectin is a robust facilitator of endothelial differentiation of blood mononuclear cells in vitro. We have found that TNFα treatment of monocytes significantly increased expression of α(5)β(1) integrin, a major fibronectin receptor enriched on endothelial cells, leading to a consequent fourfold increase in fibronectin adhesion. Furthermore, TNFα-treated monocytes upregulated expression of endothelial markers, flk-1(VEGFR2/KDR) and VE-cadherin. Integrin α(5) subunit inhibitory antibodies blocked adhesion to fibronectin as well as consequent upregulation of flk-1 and VE-cadherin transcripts, implying a role for outside-in signaling by the α(5)β(1) integrin after binding fibronectin. Finally, treatment of mouse tumors with anti-α(5) antibodies reduced accumulation of tumor vascular leukocytes in vivo. Our studies suggest that tumor cell-derived TNFα constitutes a tumor microenvironment signal that promotes differentiation of tumor-associated monocytes toward a proangiogenic/provasculogenic myeloid-endothelial phenotype via upregulation of the fibronectin receptor α(5)β(1).
Transfusion Medicine Reviews. Oct, 2011 | Pubmed ID: 21664104
Transfusion medicine for the resuscitation of patients with massive hemorrhage has recently advanced from reactive, supportive treatment with crystalloid and red blood cell therapy to use of standardized massive transfusion protocols (MTPs). Through MTPs, medical facilities are able to standardize the most effective posthemorrhage treatments and execute them rapidly while reducing potential waste of blood products. Damage control resuscitation is an example of an MTP, where patients are (1) allowed more permissive hypotension, (2) spared large volumes of crystalloid/colloid therapy (through low volume resuscitation), and (3) transfused with blood products preemptively using a balanced ratio of plasma and platelets to red blood cells. This focused approach improves the timely availability of blood components during resuscitation. However, the use of MTPs remains controversial. This review describes published experiences with MTPs and illustrates the potential value of several MTPs currently utilized by academic transfusion services.
Transfusion. Sep, 2011 | Pubmed ID: 21896029
Lessons from Genetically Altered Mesenchymal Stem Cells (MSCs); Candidates for Improved MSC-Directed Myocardial Repair
Cell Transplantation. Nov, 2011 | Pubmed ID: 22080676
The regenerative and reparative potential of Mesenchymal Stem Cells (MSCs) make them attractive candidates for numerous cell-directed therapies. The variant degree of tissue repair by transplanted MSCs has been assessed in several published reports. There are many gaps in the knowledge of MSC biology and the underlying reasons for their disparate effectiveness in tissue repair. This review examines successful pre-clinical models of MSC-directed repair, particularly of myocardial repair, in an attempt to shed light into the events dictating MSC therapeutic efficacy. The reparative advantage of genetically altered MSCs will be described. This overview will elucidate possible molecular mechanisms that can influence MSC engraftment, differentiation, self-renewal, and ultimately increase wound repair.
Vitamins and Hormones. 2011 | Pubmed ID: 22127236
Mesenchymal stem cells (MSCs) have the ability to self-renew and differentiate into multiple lineages making them an appropriate candidate for stem cell therapy. In spite of achieving considerable success in preclinical models, limited success has been achieved in clinical settings with MSCs. A major impediment that is faced is low survival of MSCs in injured tissues following implantation. In order to enhance the reparative properties of MSCs, it is vital to understand the molecular signals that regulate MSC survival and self-renewal. This review assimilates information that characterizes MSCs and mentions their utilization in myocardial infarction therapy. Additionally, our attempt herein is to gather pertinent published information regarding the role of canonical Wnt and BMP signaling in regulating the potential of MSCs to self-renew, proliferate, differentiate, and survive.
Pyrvinium, a Potent Small Molecule Wnt Inhibitor, Increases Engraftment and Inhibits Lineage Commitment of Mesenchymal Stem Cells (MSCs)
Wound Repair and Regeneration : Official Publication of the Wound Healing Society [and] the European Tissue Repair Society. Feb, 2012 | Pubmed ID: 22332749
We and others have found that Wnt signaling inhibition is important in mesenchymal stem cell (MSC) self-renewal. Pyrvinium was identified as a potent Wnt inhibitor in a chemical screen for small molecules. In the present study, we hypothesized that pyrvinium will enhance MSC self-renewal to improve the clinical efficacy of MSC therapy. Pyrvinium increased MSC proliferation in vitro while inhibiting their osteogenic and chondrogenic lineage commitment by reducing cytoplasmic β-catenin. Although MSCs are a promising target for cell therapy, strategies to enhance their survival and maintain their stemness in the wounded area are essential. Using an in vivo model of granulation tissue formation, we demonstrated that pyrvinium enhanced long-term MSC engraftment. Pyrvinium-treated MSC-generated granulation tissue also demonstrated less ectopic differentiation into bone or cartilage. This study highlights the potential of using a therapeutic Wnt inhibitor to enhance MSC-driven regenerative therapy.
Mesenchymal Stem Cell Transplantation for the Infarcted Heart: a Role in Minimizing Abnormalities in Cardiac-specific Energy Metabolism
American Journal of Physiology. Endocrinology and Metabolism. Jan, 2012 | Pubmed ID: 21971524
Intense interest has been focused on cell-based therapy for the infarcted heart given that stem cells have exhibited the ability to reduce infarct size and mitigate cardiac dysfunction. Despite this, it is unknown whether mesenchymal stem cell (MSC) therapy can prevent metabolic remodeling following a myocardial infarction (MI). This study examines the ability of MSCs to rescue the infarcted heart from perturbed substrate uptake in vivo. C57BL/6 mice underwent chronic ligation of the left anterior descending coronary artery to induce a MI. Echocardiography was performed on conscious mice at baseline as well as 7 and 23 days post-MI. Twenty-eight days following the ligation procedure, hyperinsulinemic euglycemic clamps assessed in vivo insulin sensitivity. Isotopic tracer administration evaluated whole body, peripheral tissue, and cardiac-specific glucose and fatty acid utilization. To gain insight into the mechanisms by which MSCs modulate metabolism, mitochondrial function was assessed by high-resolution respirometry using permeabilized cardiac fibers. Data show that MSC transplantation preserves insulin-stimulated fatty acid uptake in the peri-infarct region (4.25 ± 0.64 vs. 2.57 ± 0.34 vs. 3.89 ± 0.54 μmol·100 g(-1)·min(-1), SHAM vs. MI + PBS vs. MI + MSC; P < 0.05) and prevents increases in glucose uptake in the remote left ventricle (3.11 ± 0.43 vs. 3.81 ± 0.79 vs. 6.36 ± 1.08 μmol·100 g(-1)·min(-1), SHAM vs. MI + PBS vs. MI + MSC; P < 0.05). This was associated with an enhanced efficiency of mitochondrial oxidative phosphorylation with a respiratory control ratio of 3.36 ± 0.18 in MSC-treated cardiac fibers vs. 2.57 ± 0.14 in the infarct-only fibers (P < 0.05). In conclusion, MSC therapy exhibits the potential to rescue the heart from metabolic aberrations following a MI. Restoration of metabolic flexibility is important given the metabolic demands of the heart and the role of energetics in the progression to heart failure.
Transfusion Medicine Illustrated. Profound Piperacillin-mediated Drug-induced Immune Hemolysis in a Patient with Cystic Fibrosis
Transfusion. Jan, 2012 | Pubmed ID: 22032241