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Endothelial Progenitor Cells (endothelial + progenitor_cell)
Selected AbstractsIn Vivo Perfusion of Human Skin Substitutes With Microvessels Formed by Adult Circulating Endothelial Progenitor CellsDERMATOLOGIC SURGERY, Issue 2 2008ELAINE F. KUNG MD BACKGROUND At present, tissue-engineered human skin substitutes (HSSs) mainly function as temporary bioactive dressings due to inadequate perfusion. Failure to form functional vascular networks within the initial posttransplantation period compromises cell survival of the graft and its long-term viability in the wound bed. OBJECTIVES Our goal was to demonstrate that adult circulating endothelial progenitor cells (EPCs) seeded onto HSS can form functional microvessels capable of graft neovascularization and perfusion. MATERIALS AND METHODS Adult peripheral blood mononuclear cells (PBMCs) underwent CD34 selection and endothelial cell (EC) culture conditions. After in vitro expansion, flow cytometry verified EC phenotype before their incorporation into HSS. After 2 weeks in vivo, immunohistochemical analysis, immunofluorescent microscopy, and microfil polymer perfusion were performed. RESULTS CD34+ PBMCs differentiated into EPC demonstrating characteristic EC morphology and expression of CD31, Tie-2, and E-selectin after TNF,-induction. Numerous human CD31 and Ulex europaeus agglutinin-1 (UEA-1) microvessels within the engineered grafts (HSS/EPCs) inosculated with recipient murine circulation. Limitation of murine CD31 immunoreactivity to HSS margins showed angiogenesis was attributable to human EPC at 2 weeks posttransplantation. Delivery of intravenous rhodamine-conjugated UEA-1 and microfil polymer to HSS/EPCs demonstrated enhanced perfusion by functional microvessels compared to HSS control without EPCs. CONCLUSION We successfully engineered functional microvessels in HSS by incorporating adult circulating EPCs. This autologous EC source can form vascular conduits enabling perfusion and survival of human bioengineered tissues. [source] Enhancement of Viability of Fat Grafts in Nude Mice by Endothelial Progenitor CellsDERMATOLOGIC SURGERY, Issue 12 2006CHENGGANG YI MD BACKGROUND A recent discovery showed that endothelial progenitor cells (EPCs) could augment collateral vessel growth to ischemic tissues. OBJECTIVE The objective was to demonstrate the effects of EPCs on the vasculogenesis and survival of free transplanted fat tissues in nude mice. METHODS EPCs from human donors were cultured in vitro for 7 days. Human fat tissues were injected subcutaneously into the scalps of 20 6-week-old nude male mice. EPCs stained with CM-DiI were mixed with the transplanted fat tissues and injected into the mice. EBM-2 medium was used as control group. The animals were euthanized 15 weeks after the procedure. Graft volume were measured, and histologic evaluation was performed. The central part of fat tissues was histologically evaluated 15 weeks after the fat injection. RESULTS The survival volume of the experimental group was significantly greater than that of the control group (p< .05). Less cyst formation and fibrosis was obtained in the experimental group. Histologic evaluation of the central part of fat tissues 15 weeks after the fat injection showed that capillary densities increased markedly in the experimental group mice. CONCLUSION The results indicate that EPCs have the ability to enhance the survival and the quality of the transplanted fat tissues. [source] Endothelial Progenitor Cells: A Promising Therapeutic Alternative for Cardiovascular DiseaseJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2007CHUNMING DONG The integrity and functional activity of the endothelial monolayer play a critical role in preventing atherosclerotic disease progression. Endothelial cell (EC) damage by atherosclerosis risk factors can result in EC apoptosis with loss of the integrity of the endothelium. Thus, approaches to repair the injured vessels with the goal of regenerating ECs have been tested in preclinical experimental models and in clinical studies. Indeed, endothelial progenitor cells (EPCs) originating from the bone marrow have been shown to incorporate into sites of neovascularization and home to sites of endothelial denudation. These cells may provide an endogenous repair mechanism to counteract ongoing risk factor-induced endothelial injury and to replace dysfunctional endothelium. Risk factors for coronary artery disease, such as age, smoking, hypertension, hyperlipidemia, and diabetes, however, reduce the number and functional activity of circulating EPCs, potentially restricting the therapeutic prospective of progenitor cells and limiting the regenerative capacity. Furthermore, the impairment of EPCs by risk factors may contribute to atherogenesis and atherosclerotic disease progression. The article reviews the role of EPCs in atherogenesis and in predicting cardiovascular outcomes, and highlights the potential challenges in developing therapeutic strategies aiming to interfere with the balance of injury and repair mechanisms. [source] Circulating Endothelial Progenitor Cells During Normal Pregnancy and Pre-EclampsiaAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2006Keiichi Matsubara Problem Endothelial progenitor cell (EPC), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero-placental circulation. We evaluated whether EPC proliferation in pre-eclampsia (PE) differed from that in normal pregnancy. Method of study EPC number in peripheral blood (20 non-pregnancy, 36 normal pregnancy, 10 PE) was measured using flow cytometry. Peripheral blood mononuclear cell was cultured for 7 days and EPC proliferation was assessed based on detection of the uptake of acetylated low-density lipoprotein and lectin. Furthermore, the proliferative activity induced by angiotensin II (Ang II) and tumor necrosis factor- , (TNF- ,) was measured by BrdU assay. Results EPC number in peripheral blood did not differ significantly between PE and normal pregnancy; however, EPC proliferation was significantly increased in PE. Furthermore, Ang II and TNF- , induced the proliferation of EPC derived from patients with PE. Conclusions In PE, some factors including Ang II and TNF- , stimulated EPC proliferation; however, the impairment of EPC mobilization into systemic circulation by serum factors may contribute to insufficient regeneration of EC in disturbed utero-placental circulation of PE. [source] Circulating Endothelial Progenitor Cells After Kidney TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2005María José Soler Circulating endothelial progenitor cells (EPCs) promote vascular repair and maintain integrity of the endothelial monolayer. Reduced EPCs number has been associated with endothelial dysfunction in various cardiovascular diseases. Cardiovascular disease risk is higher in renal transplant patients (RT) than the general population. We studied EPCs number and proliferation in RT, and examined the association with other cardiovascular risk factors such as reduced glomerular filtration rate (GFR) and LDL cholesterol. EPCs concentration was determined in 94 RT and 39 control subjects (C) by flow cytometry. EPCs proliferation was also studied after 7 days in culture. EPCs concentration was significantly reduced in RT versus C (median 33.5 [5,177] vs. 53 [9,257] EPCs/105 PMN cells, p = 0.006). EPCs proliferation was also reduced in RT versus C (mean ± SD; 372.7 ± 229.3 vs. 539.8 ± 291.3 EPCs × field, p = 0.003). In multiple regression analysis, GFR, HDL, LDL and body weight were independent predictors of EPCs concentration in RT (r2= 0.25, p < 0.001). EPCs number is reduced in RT, particularly in patients with reduced GFR. Moreover, EPCs from RT studied in vitro, showed reduced proliferation, which is a sign of functional impairment. These alterations may be involved in increased cardiovascular risk of RT. [source] New Insights in Vascular Development: Vasculogenesis and Endothelial Progenitor CellsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009S. Käßmeyer Summary In the course of new blood vessel formation, two different processes , vasculogenesis and angiogenesis , have to be distinguished. The term vasculogenesis describes the de novo emergence of a vascular network by endothelial progenitors, whereas angiogenesis corresponds to the generation of vessels by sprouting from pre-existing capillaries. Until recently, it was thought that vasculogenesis is restricted to the prenatal period. During the last decade, one of the most fascinating innovations in the field of vascular biology was the discovery of endothelial progenitor cells and vasculogenesis in the adult. This review aims at introducing the concept of adult vasculogenesis and discusses the efforts to identify and characterize adult endothelial progenitors. The different sources of adult endothelial progenitors like haematopoietic stem cells, myeloid cells, multipotent progenitors of the bone marrow, side population cells and tissue-residing pluripotent stem cells are considered. Moreover, a survey of cellular and molecular control mechanisms of vasculogenesis is presented. Recent advances in research on endothelial progenitors exert a strong impact on many different disciplines and provide the knowledge for functional concepts in basic fields like anatomy, histology as well as embryology. [source] Two-Year Clinical Registry Follow-up of Endothelial Progenitor Cell Capture Stent Versus Sirolimus-Eluting Bioabsorbable Polymer-Coated Stent Versus Bare Metal Stents in Patients Undergoing Primary Percutaneous Coronary Intervention for ST Elevation Myocardial InfarctionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2010ERIC CHONG M.B.B.S., F.A.M.S., M.R.C.P. Background: Endothelial progenitor cell (EPC) capture stent is designed to promote rapid endothelization and healing and is potentially useful in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). We studied the intermediate-term efficacy and safety of EPC stent and compared that with sirolimus-eluting bioabsorbable polymer stent (CURA) and bare metal stent (BMS) in AMI patients. Methodology: Patients presenting with AMI who underwent primary PCI with the respective stents between January 2004 and June 2006 were enrolled in the single-center clinical registry. The study end-points were major adverse cardiac events (MACE) and stent thrombosis. Results: A total of 366 patients (EPC = 95, CURA = 53, BMS 218) were enrolled. Baseline demographics including age, gender, diabetes, renal impairment, predischarge left ventricular ejection fraction, and creatinine kinase level were comparable among the groups. Procedural success rate was 99.5%. Post-procedural thrombolysis in myocardial infarction (TIMI) 3 flow was achieved in EPC 91.6%, CURA 96.2%, and BMS 88.5% (P = 0.209). At 2 years, the MACE rate was EPC 13.7%, CURA 15.1%, and BMS 19.7% (P = 0.383). Target vessel revascularizations (TVR) were EPC 4.2%, CURA 9.4%, and BMS 6.0% (P = 0.439). Nonfatal myocardial infarctions were EPC 1.1%, CURA 3.8%, and BMS 4.1% (P = 0.364). One patient in the EPC group had acute stent thrombosis. There was no late stent thrombosis in the EPC group. Conclusion: EPC stent appeared to be safe and had comparable clinical efficacy with a BMS when used in the AMI setting. At 2-year follow-up, the EPC group showed favorable, single-digit TVR rate and stent thrombosis remained a low-event occurrence. (J Interven Cardiol 2010;23:101-108) [source] Circulating Endothelial Progenitor Cells During Normal Pregnancy and Pre-EclampsiaAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2006Keiichi Matsubara Problem Endothelial progenitor cell (EPC), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero-placental circulation. We evaluated whether EPC proliferation in pre-eclampsia (PE) differed from that in normal pregnancy. Method of study EPC number in peripheral blood (20 non-pregnancy, 36 normal pregnancy, 10 PE) was measured using flow cytometry. Peripheral blood mononuclear cell was cultured for 7 days and EPC proliferation was assessed based on detection of the uptake of acetylated low-density lipoprotein and lectin. Furthermore, the proliferative activity induced by angiotensin II (Ang II) and tumor necrosis factor- , (TNF- ,) was measured by BrdU assay. Results EPC number in peripheral blood did not differ significantly between PE and normal pregnancy; however, EPC proliferation was significantly increased in PE. Furthermore, Ang II and TNF- , induced the proliferation of EPC derived from patients with PE. Conclusions In PE, some factors including Ang II and TNF- , stimulated EPC proliferation; however, the impairment of EPC mobilization into systemic circulation by serum factors may contribute to insufficient regeneration of EC in disturbed utero-placental circulation of PE. [source] Potential manipulation of endothelial progenitor cells in diabetes and its complicationsDIABETES OBESITY & METABOLISM, Issue 7 2010G. P. Fadini Diabetes mellitus increases cardiovascular risk through its negative impact on vascular endothelium. Although glucotoxicity and lipotoxicity account for endothelial cell damage, endothelial repair is also affected by diabetes. Endothelial progenitor cells (EPCs) are involved in the maintenance of endothelial homoeostasis and in the process of new vessel formation. For these reasons, EPCs are thought to have a protective impact within the cardiovascular system. In addition, EPCs appear to modulate the functioning of other organs, providing neurotropic signals and promoting repair of the glomerular endothelium. The exact mechanisms by which EPCs provide cardiovascular protection are unknown and the definition of EPCs is not standardized. Notwithstanding these limitations, the literature consistently indicates that EPCs are altered in type 1 and type 2 diabetes and in virtually all diabetic complications. Moreover, experimental models suggest that EPC-based therapies might help prevent or reverse the features of end-organ complications. This identifies EPCs as having a novel pathogenic role in diabetes and being a potential therapeutic target. Several ways of favourably modulating EPCs have been identified, including lifestyle intervention, commonly used medications and cell-based approaches. Herein, we provide a comprehensive overview of EPC pathophysiology and the potential for EPC modulation in diabetes. [source] Effect of atorvastatin on microRNA 221,/,222 expression in endothelial progenitor cells obtained from patients with coronary artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2009Y. Minami Abstract Background, Endothelial progenitor cells (EPCs) play an important role in the maintenance of vascular integrity. Lipid lowering therapy (LLT) with statins may contribute to biologically relevant activities including the proliferation of endothelial cells. The physiological role of microRNA (miR)-221/222, a newly discovered class of small RNA, is closely linked to the proliferation of endothelial cells. We therefore investigated whether LLT with statins might affect miR-221/222 expression in EPCs obtained from patients with coronary artery disease (CAD). Materials and methods, This study included 44 patients with stable CAD and 22 subjects without CAD (non-CAD). Patients with CAD were randomized to 12 months of LLT with atorvastatin (10 mg day,1) or pravastatin (10 mg day,1). EPCs were obtained from peripheral blood at baseline and after 12 months of statin therapy. Levels of miR-221/222 in EPCs were measured by real-time RT-PCR. Results, Levels of miR-221/222 were significantly higher in the CAD group than in the non-CAD group (P < 0·01). Levels of miR-221/222 were weakly negatively correlated with EPC number in the CAD group. After 12 months of therapy, changes in lipid profiles were greater in the atorvastatin group than in the pravastatin group. LLT with atorvastatin markedly increased EPC numbers and decreased miR-221/222 levels (all P < 0·05), whereas LLT with pravastatin did not change EPC numbers or miR-221/222 levels. Conclusions, This study demonstrates that LLT with atorvastatin increases EPC numbers and decreases miR-221/222 levels in patients with CAD, possibly contributing to the beneficial effects of LLT with atorvastatin in this disorder. [source] LDL lipid apheresis rapidly increases peripheral endothelial progenitor cell competenceJOURNAL OF CLINICAL APHERESIS, Issue 5 2009Daniel Patschan Abstract Background and Aim: Endothelial progenitor cells (EPCs) have been shown to promote neovascularization under physiologic and pathologic conditions. Statins have been documented to increase the total number of circulating EPCs in long-term treated patients. Lipid apheresis is used to treat patient with refractory hyperlipidemia. The aim of our study was to evaluate whether lipid apheresis is associated with EPC mobilization. Methods: Thirteen patients with refractory hyperlipidemia (analysis at the beginning and at the end of a single lipid apheresis treatment) and 10 healthy controls were included into the study. For quantifying total peripheral EPCs, CD133+/Flk-1+ myelo-monocytic blood cells were enumerated by flow cytometry. The proliferative potential of EPCs was evaluated by a "colony-forming unit" assay. In some patients, EPC eNOS expression was evaluated before and after treatment. Results: Circulating EPCs and the cells' proliferative activity were lower in hyperlipidemia patients as compared to controls (0.14 ± 0.07 vs. 0.6 ± 0.14, P = 0.01, and 13.9 ± 4.9 vs. 45.6 ± 8.1, P = 0.0007). Lipid apheresis treatment was not associated with an increase in total EPCs. The cells' proliferative activity was strongly stimulated by lipid apheresis as reflected by an increase in the number of EPC colonies (13.9 ± 4.9 to 34.1 ± 7.3, P = 0.035). Analysis of EPC eNOS expression revealed a threefold increase in the cellular expression intensity after lipid apheresis. Conclusions: Patients with refractory hyperlipidemia exhibit lower peripheral EPC numbers and a lower proliferative activity of circulating EPCs than healthy controls. A single lipid apheresis treatment significantly stimulates EPC proliferation, it furthermore increases cellular eNOS. In summary, these results show that lipid apheresis mediates beneficial effects on the EPC system as an essential element in the process of vascular repair in the human organism. J. Clin. Apheresis 2009. © 2009 Wiley-Liss, Inc. [source] Cleaved high molecular weight kininogen inhibits tube formation of endothelial progenitor cells via suppression of matrix metalloproteinase 2JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2010Y. WU Summary.,Background and objective:,Endothelial progenitor cells (EPCs) contribute to postnatal neovascularization, thus promoting wide interest in their therapeutic potential in vascular injury and prevention of their dysfunction in cardiovascular diseases. Cleaved high molecular weight kininogen (HKa), an activation product of the plasma kallikrein-kinin system (KKS), inhibits the functions of differentiated endothelial cells including in vitro and in vivo angiogenesis. In this study, our results provided the first evidence that HKa is able to target EPCs and inhibits their tube forming capacity. Methods and results:,We determined the effect of HKa on EPCs using a three-dimensional vasculogenesis assay. Upon stimulation with vascular endothelial growth factor (VEGF) alone, EPCs formed vacuoles and tubes, and differentiated into capillary-like networks. As detected by gelatinolytic activity assay, VEGF stimulated secretion and activation of matrix metallopeptidase 2 (MMP-2), but not MMP-9, in the conditioned medium of 3D culture of EPCs. Specific inhibition or gene ablation of MMP-2, but not MMP-9, blocked the vacuole and tube formation by EPCs. Thus, MMP-2 is selectively required for EPC vasculogenesis. In a concentration-dependent manner, HKa significantly inhibited tube formation by EPCs and the conversion of pro-MMP-2 to MMP-2. Moreover, HKa completely blocked the association between pro-MMP-2 and ,v,3 integrin, and its inhibition of MMP-2 activation was dependent on the presence of ,v,3 integrin. In a purified system, HKa did not directly inhibit MMP-2 activity. Conclusions:,HKa inhibits tube forming capacity of EPCs by suppression of MMP-2 activation, which may constitute a novel link between activation of the KKS and EPC dysfunction. [source] Thrombin and PAR-1 stimulate differentiation of bone marrow-derived endothelial progenitor cellsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2006S. T. TARZAMI Summary., Endothelial progenitor cells (EPCs) from the bone marrow play an important role in vascular response to injury and ischemia. The mediators involved in the mobilization, recruitment, proliferation and differentiation of EPCs are not fully understood. In this study, the role of coagulation factor thrombin and protease-activated receptor-1 (PAR-1) on bone marrow-derived cell proliferation and differentiation was investigated. Bone marrow cells (BMCs) were isolated from C57/BL6 mice and plated on fibronectin-coated flasks. Cell characteristics, proliferation and the expression of endothelial cell markers were determined using immunohistochemistry, thymidine uptake and fluorescence activated-cell sorting (FACS), respectively. The results show that thrombin stimulated enrichment of bone marrow cells with endothelial morphology, exhibiting acetylated-low-density lipoprotein (LDL) uptake and isolectin staining. Thrombin or PAR-1-activating peptide produced a 2- to 3-fold increase in the total number of cells as well as an increase in vascular endothelial (VE)-cadherin-positive cells. Thrombin treatment of VE-cadherin-negative cells prepared after cell sorting resulted in the generation of 3- to 4-fold higher VE-cadherin-positive cells than the untreated cultures. Increase in VE-cadherin-positive cells was inhibited by hirudin and efegatran. These results provide first evidence for a novel activity of thrombin and PAR-1 on bone marrow progenitor cell proliferation and EPC differentiation, and suggest their potential role in vascular regeneration and recanalization of thrombus. [source] Endothelial progenitor cell transplantation improves long-term stroke outcome in miceANNALS OF NEUROLOGY, Issue 4 2010Yongfeng Fan PhD Objective Endothelial progenitor cells (EPCs) play an important role in tissue repairing and regeneration in ischemic organs, including the brain. However, the cause of EPC migration and the function of EPCs after ischemia are unclear. In this study, we demonstrated the effects of EPCs on ischemic brain injury in a mouse model of transient middle cerebral artery occlusion (tMCAO). Methods Circulating human EPCs were characterized with immunofluorescent staining and flow cytometry. EPCs (1 × 106) were injected into nude mice after 1 hour of tMCAO. Histological analysis and behavioral tests were performed from day 0 to 28 days after tMCAO. Results EPCs were detected in ischemic brain regions 24 hours after tMCAO. EPC transplantation significantly reduced ischemic infarct volume at 3 days after tMCAO compared with control animals (p < 0.05). CXCR4 was expressed in the majority of EPCs, and stromal-derived factor-1 (SDF-1) induced EPC migration, which was blocked by pretreated EPCs with AMD3100 in vitro. SDF-1 was upregulated in ischemic brain. Compared with control animals, injecting AMD3100-pretreated EPCs resulted in a larger infarct volume 3 days after tMCAO, suggesting that SDF-1,mediated signaling was involved in EPC-mediated neuroprotection. In addition, EPC transplantation reduced mouse cortex atrophy 4 weeks after tMCAO and improved neurobehavioral outcomes (p < 0.05). EPC injection potently increased angiogenesis in the peri-infarction area (p < 0.05). Interpretation We conclude that systemic delivery of EPCs protects the brain against ischemic injury, promotes neurovascular repair, and improves long-term neurobehavioral outcomes. Our data suggest that SDF-1,mediated signaling plays a critical role in EPC-mediated neuroprotection. ANN NEUROL 2010;67:488,497 [source] Endothelial progenitor cells: Novel players in the pathogenesis of rheumatic diseasesARTHRITIS & RHEUMATISM, Issue 11 2009Jörg H. W. Distler First page of article [source] Endothelial progenitor cells & translational researchBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2009JM Ritter No abstract is available for this article. [source] Endothelial progenitor cells and arterial functions in the late convalescence period of Kawasaki diseaseACTA PAEDIATRICA, Issue 8 2009Xiao-qin Liu Abstract Aim:, The relationship was investigated between endothelial progenitor cells (EPCs) level and arterial functions in the convalescence of Kawasaki disease (KD). Methods:, Sixty-three children were divided into coronary artery lesion (CAL) group (group 1, n = 21), non-CAL group (group 2, n = 20) and control group (group 3, n = 22). EPCs were examined by flow cytometry and arterial functions (flow-mediated dilation [FMD], carotid artery stiffness index [SI]) were measured by ultrasound. Results:, From group1 to group 3, FMD was 4.5%± 1.5%, 9.5%± 2.8% and 12.1%± 2.3% (p < 0.01 between any two groups); carotid artery SI was 4.10 ± 0.44, 3.81 ± 0.50 and 3.59 ± 0.46 (group 1 vs. group 2, p < 0.05; group 1 vs. group 3, p < 0.01; group 2 vs. group 3, p = 0.142) and the number of EPCs was 2.0 ± 0.6/,L, 4.2 ± 0.8/,L, 4.5 ± 0.7/,L (p < 0.01 for group1 vs. group 2 and group 1 vs. group 3; group 2 vs. group 3, p = 0.292). Multiple linear regressions analysis and correlation analysis identified that FMD and carotid artery SI were significant determinants of EPCs level and were all independently correlated with EPCs level. Conclusions:, Our results indicate decreased EPCs are associated with arterial dysfunction in patients with CAL in the convalescence of KD. Our findings suggest EPCs may have a role in alteration of arterial functions. [source] OXIDIZED LOW-DENSITY LIPOPROTEIN INDUCES ENDOTHELIAL PROGENITOR CELL SENESCENCE, LEADING TO CELLULAR DYSFUNCTIONCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 7 2004Toshio Imanishi SUMMARY 1.,Recent studies have revealed an association between coronary risk factors and both the number and function of bone marrow-derived endothelial progenitor cells (EPC). We investigated the effect of oxidized low-density lipoprotein (ox-LDL) on the senescence of EPC, leading to cellular dysfunction. 2.,Endothelial progenitor cells were isolated from human peripheral blood and characterized. The exposure of cultured EPC to ox-LDL (10 µg/mL) significantly accelerated the rate of senescence compared with control during 20 days in culture as determined by acidic ,-galactosidase staining. Oxidized LDL-induced EPC senescence was significantly inhibited by pretreatment with either lectin-like ox-LDL receptor-1 (LOX-1) antibody (Ab) or atorvastatin (P < 0.01). 3.,Because cellular senescence is critically influenced by telomerase, which elongates telomeres, we measured telomerase activity using a polymerase chain reaction,ELISA-based assay. Oxidized LDL significantly diminished telomerase activity to approximately 50%, an effect that was significantly abolished by pretreatment with either LOX-1 Ab or atorvastatin (P < 0.01). 4.,We examined whether ox-LDL-induced EPC senescence translates into EPC dysfunction. An MTS assay disclosed an inhibitory effect of ox-LDL on EPC proliferation. In a Matrigel assay, EPC treated with ox-LDL were less likely to participate in network fomation compared with controls. 5.,In conclusions, ox-LDL accelerates the onset of EPC senescence, which may be related to telomerase inactivation. Oxidized LDL-induced EPC senescence leads to the impairment of proliferative capacity and network formation. [source] The Effects of Ethanol Consumption on Vasculogenesis Potential in Nonhuman PrimatesALCOHOLISM, Issue 1 2008J. Koudy Williams Background:, Vasculogenesis is essential to the preservation and repair of damaged or diseased vessels. Alcohol is the most commonly abused drug among young adults, but its effects on vessel growth and repair are unknown. The basis of vascular repair is endothelial progenitor cell (EPC) recruitment to assist in the formation of new vascular network (vasculogenesis). Therefore, the objective of this study was to measure the effects of ethanol consumption on the production, mobilization and vasculogenesis potential EPCs in nonhuman primates. Methods:, Four to five year-old (young adult) male rhesus monkeys consumed monkey chow and water (Control, n = 7), or chow and water + ethanol (Alcohol, 2.45 g/d, n = 7) for 12 months. Peripheral blood (PB) and bone marrow (BM) samples were collected for fluorescence-activated cell-sorting analysis of cell surface antigens (CD45, CD31, CD44, CD133, VEGF-R2 , or KDR); and for capillary formation on Matrigel-coated plates. Results:, There were greater numbers of nonhematopoeitic stromal cells (CD45,) and putative mesenchymal progenitor cells (CD45,/CD44+) in the PB and BM of Alcohol versus Control monkeys (p < 0.05). Additionally, there were greater numbers of EPCs (CD45,/CD133+/KDR+) in the BM and PB of Alcohol versus Control monkeys (p < 0.05). However, the EPCs of Alcohol monkeys were less likely to form capillaries on matrigel-coated plates than Control monkeys (p < 0.05). Conclusions:, Ethanol consumption in monkeys markedly increased the production and mobilization of EPCs, but decreased their ability to form capillaries. The pathophysiologic consequences of such effects are unclear, but may represent an ethanol-induced chronic stress on the BM, resulting in EPC. [source] Reduced endothelial progenitor cells and brachial artery flow-mediated dilation as evidence of endothelial dysfunction in ocular hypertension and primary open-angle glaucomaACTA OPHTHALMOLOGICA, Issue 1 2010Gian Paolo Fadini Abstract. Purpose:, This study aimed to assess vascular endothelial function in patients with ocular hypertension (OHT) or primary open-angle glaucoma (POAG) by measuring: (a) endothelium-dependent flow-mediated vasodilation (FMD) of the brachial artery, and (b) circulating endothelial progenitor cells, which are believed to support the integrity of the vascular endothelium. Methods:, We enrolled 25 patients with OHT, 23 with POAG and 26 control subjects, all of whom were aged < 65 years and had no medical history of cardiovascular disease or cardiovascular risk factors. All subjects underwent a complete ophthalmological examination, biochemistry study, assessment of cardiovascular parameters, brachial artery ultrasound assessment of endothelium-dependent FMD, generic circulating progenitor cell (CPC) and circulating endothelial progenitor cell (EPC) count with the use of flow cytometry. Results:, Flow-mediated vasodilation values differed significantly in OHT (4.5 ± 1.1%; p = 0.021) and POAG (4.0 ± 0.9%; p = 0.003) patients compared with controls (7.7 ± 0.8%). The CD34+ KDR+ EPC count was markedly lower in OHT (28.0 ± 5.0; p < 0.001) and POAG (24.3 ± 3.4; p < 0.001) patients compared with controls (73.1 ± 8.1). Neither FMD not EPCs differed significantly between OHT and POAG patients. No significant differences in CPC count or cardiovascular parameters were found among OHT or POAG patients and controls. The levels of CD34+ KDR+ EPCs were directly correlated (p = 0.043) with FMD, and inversely correlated (p = 0.032) with baseline intraocular pressure in OHT and POAG patients. Conclusions:, Both OHT and POAG patients without cardiovascular risk factors have previously unreported severely reduced circulating EPCs and reduced FMD, both of which are indicators of endothelial dysfunction and increased risk of cardiovascular events. [source] Flow cytometric measurement of circulating endothelial cells: The effect of age and peripheral arterial disease on baseline levels of mature and progenitor populationsCYTOMETRY, Issue 2 2006Rebecca Gusic Shaffer Abstract Background: Age and cardiovascular disease status appear to alter numbers and function of circulating endothelial progenitor cells (EPCs). Despite no universal phenotypic definition, numerous studies have implicated progenitors with apparent endothelial potential in local responses to vascular injury and with cardiovascular disease in general. To further define the role of this lineage in peripheral artery disease (PAD), we developed a multiparameter flow cytometry assay to analyze multiple phenotypic definitions of progenitor cells (PCs), EPCs, and mature endothelial cells (ECs) and evaluate effects of age and PAD on baseline levels of each subset. Methods: Blood was collected from young healthy subjects (N = 9, mean age 33 ± 8 years), older healthy subjects (N = 13, mean age 66 ± 8 years), and older subjects with PAD (N = 15, mean age 69 ± 8 years). After ammonium chloride lysis, cells were stained and analyzed on a Becton-Dickinson LSR II with a 5-color antibody panel: FITC-anti-CD31, PE-anti-CD146, PE-anti-CD133, PerCP-Cy5.5-anti-CD3,-CD19,-CD33 (lineage panel), PE-Cy7-anti-CD34, and APC-anti-VEGF-R2. Viability was assessed by propidium iodide exclusion, and only viable, low to medium side scatter lineage-negative singlets were analyzed. In some studies, cells were sorted for morphological studies. Subsets were defined as indicated later. Results: Our results, using a comprehensive flow cytometric panel, indicate that CD133+, CD34+, and CD133+/CD34+ PCs are elevated in younger healthy individuals compared to older individuals, both healthy and with PAD. However, the number of EPCs and mature ECs did not significantly differ among the three groups. Assessment of endothelial colony forming units and dual acLDL-lectin staining supported the flow cytometric findings. Conclusions: We describe a comprehensive flow cytometric method to detect circulating mature and progenitor endothelial populations confirmed by conventional morphological and functional assays. Our findings suggest that aging may influence circulating levels of PCs, but not EPCs or ECs; PAD had no effect on baseline levels of any populations investigated. This study provides the basis for evaluating the potential effects of acute stress and therapeutic intervention on circulating progenitor and endothelial populations as a biomarker for cardiovascular status. © 2005 International Society for Analytical Cytology [source] In Vivo Perfusion of Human Skin Substitutes With Microvessels Formed by Adult Circulating Endothelial Progenitor CellsDERMATOLOGIC SURGERY, Issue 2 2008ELAINE F. KUNG MD BACKGROUND At present, tissue-engineered human skin substitutes (HSSs) mainly function as temporary bioactive dressings due to inadequate perfusion. Failure to form functional vascular networks within the initial posttransplantation period compromises cell survival of the graft and its long-term viability in the wound bed. OBJECTIVES Our goal was to demonstrate that adult circulating endothelial progenitor cells (EPCs) seeded onto HSS can form functional microvessels capable of graft neovascularization and perfusion. MATERIALS AND METHODS Adult peripheral blood mononuclear cells (PBMCs) underwent CD34 selection and endothelial cell (EC) culture conditions. After in vitro expansion, flow cytometry verified EC phenotype before their incorporation into HSS. After 2 weeks in vivo, immunohistochemical analysis, immunofluorescent microscopy, and microfil polymer perfusion were performed. RESULTS CD34+ PBMCs differentiated into EPC demonstrating characteristic EC morphology and expression of CD31, Tie-2, and E-selectin after TNF,-induction. Numerous human CD31 and Ulex europaeus agglutinin-1 (UEA-1) microvessels within the engineered grafts (HSS/EPCs) inosculated with recipient murine circulation. Limitation of murine CD31 immunoreactivity to HSS margins showed angiogenesis was attributable to human EPC at 2 weeks posttransplantation. Delivery of intravenous rhodamine-conjugated UEA-1 and microfil polymer to HSS/EPCs demonstrated enhanced perfusion by functional microvessels compared to HSS control without EPCs. CONCLUSION We successfully engineered functional microvessels in HSS by incorporating adult circulating EPCs. This autologous EC source can form vascular conduits enabling perfusion and survival of human bioengineered tissues. [source] Enhancement of Viability of Fat Grafts in Nude Mice by Endothelial Progenitor CellsDERMATOLOGIC SURGERY, Issue 12 2006CHENGGANG YI MD BACKGROUND A recent discovery showed that endothelial progenitor cells (EPCs) could augment collateral vessel growth to ischemic tissues. OBJECTIVE The objective was to demonstrate the effects of EPCs on the vasculogenesis and survival of free transplanted fat tissues in nude mice. METHODS EPCs from human donors were cultured in vitro for 7 days. Human fat tissues were injected subcutaneously into the scalps of 20 6-week-old nude male mice. EPCs stained with CM-DiI were mixed with the transplanted fat tissues and injected into the mice. EBM-2 medium was used as control group. The animals were euthanized 15 weeks after the procedure. Graft volume were measured, and histologic evaluation was performed. The central part of fat tissues was histologically evaluated 15 weeks after the fat injection. RESULTS The survival volume of the experimental group was significantly greater than that of the control group (p< .05). Less cyst formation and fibrosis was obtained in the experimental group. Histologic evaluation of the central part of fat tissues 15 weeks after the fat injection showed that capillary densities increased markedly in the experimental group mice. CONCLUSION The results indicate that EPCs have the ability to enhance the survival and the quality of the transplanted fat tissues. [source] Potential manipulation of endothelial progenitor cells in diabetes and its complicationsDIABETES OBESITY & METABOLISM, Issue 7 2010G. P. Fadini Diabetes mellitus increases cardiovascular risk through its negative impact on vascular endothelium. Although glucotoxicity and lipotoxicity account for endothelial cell damage, endothelial repair is also affected by diabetes. Endothelial progenitor cells (EPCs) are involved in the maintenance of endothelial homoeostasis and in the process of new vessel formation. For these reasons, EPCs are thought to have a protective impact within the cardiovascular system. In addition, EPCs appear to modulate the functioning of other organs, providing neurotropic signals and promoting repair of the glomerular endothelium. The exact mechanisms by which EPCs provide cardiovascular protection are unknown and the definition of EPCs is not standardized. Notwithstanding these limitations, the literature consistently indicates that EPCs are altered in type 1 and type 2 diabetes and in virtually all diabetic complications. Moreover, experimental models suggest that EPC-based therapies might help prevent or reverse the features of end-organ complications. This identifies EPCs as having a novel pathogenic role in diabetes and being a potential therapeutic target. Several ways of favourably modulating EPCs have been identified, including lifestyle intervention, commonly used medications and cell-based approaches. Herein, we provide a comprehensive overview of EPC pathophysiology and the potential for EPC modulation in diabetes. [source] Irradiated cultured apoptotic peripheral blood mononuclear cells regenerate infarcted myocardiumEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2009H. J. Ankersmit Abstract Background, Acute myocardial infarction (AMI) is followed by post AMI cardiac remodelling, often leading to congestive heart failure. Homing of c-kit+ endothelial progenitor cells (EPC) has been thought to be the optimal source for regenerating infarcted myocardium. Methods, Immune function of viable peripheral blood mononuclear cells (PBMC) was evaluated after co-culture with irradiated apoptotic PBMC (IA-PBMC) in vitro. Viable PBMC, IA-PBMC and culture supernatants (SN) thereof were obtained after 24 h. Reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay were utilized to quantify interleukin-8 (IL-8), vascular endothelial growth factor, matrix metalloproteinase-9 (MMP9) in PBMC, SN and SN exposed fibroblasts. Cell suspensions of viable- and IA-PBMC were infused in an experimental rat AMI model. Immunohistological analysis was performed to detect inflammatory and pro-angiogenic cells within 72 h post-infarction. Functional data and determination of infarction size were quantified by echocardiography and Elastica van Gieson staining. Results, The IA-PBMC attenuated immune reactivity and resulted in secretion of pro-angiogenic IL-8 and MMP9 in vitro. Fibroblasts exposed to viable and IA-PBMC derived SN caused RNA increment of IL-8 and MMP9. AMI rats that were infused with IA-PBMC cell suspension evidenced enhanced homing of endothelial progenitor cells within 72 h as compared to control (medium alone, viable-PBMC). Echocardiography showed a significant reduction in infarction size and improvement in post AMI remodelling as evidenced by an attenuated loss of ejection fraction. Conclusion, These data indicate that infusion of IA-PBMC cell suspension in experimental AMI circumvented inflammation, caused preferential homing of regenerative EPC and replaced infarcted myocardium. [source] Effect of atorvastatin on microRNA 221,/,222 expression in endothelial progenitor cells obtained from patients with coronary artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2009Y. Minami Abstract Background, Endothelial progenitor cells (EPCs) play an important role in the maintenance of vascular integrity. Lipid lowering therapy (LLT) with statins may contribute to biologically relevant activities including the proliferation of endothelial cells. The physiological role of microRNA (miR)-221/222, a newly discovered class of small RNA, is closely linked to the proliferation of endothelial cells. We therefore investigated whether LLT with statins might affect miR-221/222 expression in EPCs obtained from patients with coronary artery disease (CAD). Materials and methods, This study included 44 patients with stable CAD and 22 subjects without CAD (non-CAD). Patients with CAD were randomized to 12 months of LLT with atorvastatin (10 mg day,1) or pravastatin (10 mg day,1). EPCs were obtained from peripheral blood at baseline and after 12 months of statin therapy. Levels of miR-221/222 in EPCs were measured by real-time RT-PCR. Results, Levels of miR-221/222 were significantly higher in the CAD group than in the non-CAD group (P < 0·01). Levels of miR-221/222 were weakly negatively correlated with EPC number in the CAD group. After 12 months of therapy, changes in lipid profiles were greater in the atorvastatin group than in the pravastatin group. LLT with atorvastatin markedly increased EPC numbers and decreased miR-221/222 levels (all P < 0·05), whereas LLT with pravastatin did not change EPC numbers or miR-221/222 levels. Conclusions, This study demonstrates that LLT with atorvastatin increases EPC numbers and decreases miR-221/222 levels in patients with CAD, possibly contributing to the beneficial effects of LLT with atorvastatin in this disorder. [source] CD31+/Annexin V+ microparticles in healthy offsprings of patients with coronary artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2009D. Bulut ABSTRACT Background, First-degree relatives of patients with premature coronary artery disease (CAD) develop endothelial dysfunction even in the case they are apparently healthy. In this study we wanted to clarify whether reduced blood levels of circulating endothelial progenitor cells (EPCs), an endogenous repair mechanism to replace dysfunctional endothelium, or elevated endothelial-derived microparticles (EMPs), an indicator and a mediator of increased endothelial cell damage/apoptosis, are an initial step in the pathogenesis of endothelial dysfunction in genetically predisposed subjects. Materials and methods, Fifty-six healthy young men (aged 23 to 31 years) from a fire brigade were enrolled, of which 20 subjects had a positive family history (FH) for premature CAD. Subjects with or without a positive FH did not differ with respect to age, body mass index, risk factors and C-reactive protein. Endothelial function was assessed by hyperaemia-mediated relaxation of the brachial artery, blood levels of EPCs (VEGFR2+CD34+ cells) and number of EMPs (CD31+(bright)/Annexin V+ particles) were analysed by flow cytometry. Results, Hyperaemia-mediated relaxation of the brachial artery was similar in both groups, and the blood levels of EPCs were comparable. However, the number of EMPs were significantly increased in subjects with a positive FH compared to those with a negative FH (neg. FH: 55·31 ± 4·88 vs. pos. FH: 70·37 ± 6·32 particles µL,1 platelet poor plasma; P < 0·05). Number of EMPs correlate inversely with the FMD response. Conclusions, These results suggest that increased plasma levels of EMPs may be an initial step in the development of endothelial dysfunction in genetically predisposed subjects. [source] Anaemia after renal transplantationEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2005M. Lorenz Abstract Anaemia is a frequent complication among long-term renal transplant recipients. A prevalence of approximately 40% has been reported in several studies. If renal function declines to stage 5 kidney disease, the prevalence of anaemia in kidney transplants is even higher. A positive correlation between haemoglobin concentration and creatinine clearance has been reported, which is a function of endogenous erythropoietin production by the functioning graft. Inflammation related to a retained kidney graft may cause hypo-responsiveness to erythropoietic agents once kidney transplant recipients return to dialysis. Furthermore, the use of azathioprine, mycophenolate mofetil and sirolimus may be associated with post-transplant anaemia. Along with erythropoietin deficiency, depletion of iron stores is one of the major reasons for anaemia in the kidney transplant population. The proportion of hypochromic red blood cells appears to be a useful parameter to measure iron supply and utilization as well as to estimate mortality risks in kidney transplant recipients. While anaemia is an important cardiovascular risk-factor after transplantation, our data suggest that anaemia is not associated with mortality and graft loss. Nevertheless, inadequate attention is paid so far to the management of anaemia after renal transplantation. A promising future aspect for risk reduction of cardiovascular disease includes the effect of erythropoietic agents on endothelial progenitor cells. [source] Transplantation of umbilical cord blood-derived endothelial progenitor cells: a promising method of therapeutic revascularisationEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2006Lei Zhang Abstract:, Therapeutic neovascularisation by endothelial progenitor cells (EPCs) mediated vascular regeneration is becoming a novel option for the treatment of ischaemic diseases. Recently, human umbilical cord blood (CB) has been found to contain a large number of EPCs and transplantation of CB EPCs led to a successful salvage of the ischaemic limbs through improvement in blood perfusion, indicating the feasibility of using CB cells for therapeutic revascularisation. This review will summarise recent studies in therapeutic revascularisation using CB cells and discuss the potential clinical utilisation of CB cells in ischaemic diseases. [source] Therapeutic angiogenesis and vasculogenesis for tissue regenerationEXPERIMENTAL PHYSIOLOGY, Issue 3 2005Paolo Madeddu Therapeutic angiogenesis/vasculogenesis holds promise for the cure of ischaemic disease. The approach postulates the manipulation of spontaneous healing response by supplementation of growth factors or transplantation of vascular progenitor cells. These supplements are intended to foster the formation of arterial collaterals and promote the regeneration of damaged tissues. Angiogenic factors are generally delivered in the form of recombinant proteins or by gene transfer using viral vectors. In addition, new non-viral methods are gaining importance for their safer profile. The association of growth factors with different biological activity might offer distinct advantages in terms of efficacy, yet combined approaches require further optimization. Alternatively, substances with pleiotropic activity might be considered, by virtue of their ability to target multiple mechanisms. For instance, some angiogenic factors not only stimulate the growth of arterioles and capillaries, but also inhibit vascular destabilization triggered by metabolic and oxidative stress. Transplantation of endothelial progenitor cells was recently proposed for the treatment of peripheral and myocardial ischaemia. Progenitor cells can be transplanted either without any preliminary conditioning or after ex vivo genetic manipulation. Delivery of genetically modified progenitor cells eliminates the drawback of immune response against viral vectors and makes feasible repeating the therapeutic procedure in case of injury recurrence. It is envisioned that these new approaches of regenerative medicine will open unprecedented opportunities for the care of life-threatening diseases. [source] | ||||||||||||||||||||||||||||||||||