Glucose tolerance is negatively associated with circulating progenitor cell levels

AIMS/HYPOTHESIS: Circulating progenitor cells participate in cardiovascular homeostasis. Depletion of the pool of endothelial progenitor cells (EPCs) is associated with increased cardiovascular risk. Furthermore, EPCs are reduced in the presence of classical risk factors for atherosclerotic disease, including diabetes mellitus. This study was designed to evaluate progenitor cell levels in volunteers with different degrees of glucose tolerance. METHODS: Cardiovascular parameters and the levels of circulating CD34(+) and CD34(+) kinase insert domain receptor (KDR)(+) cells were determined in 219 middle-aged individuals with no pre-diagnosed alterations in carbohydrate metabolism. Glucose tolerance was determined by fasting and 2 h post-challenge glucose levels, with IFG and IGT considered as pre-diabetic states. RESULTS: CD34(+) and CD34(+)KDR(+) cells were significantly reduced in individuals who were found to have diabetes mellitus, and were negatively correlated with both fasting and post-challenge glucose in the whole population. While only CD34(+) cells, but not CD34(+)KDR(+) cells, were significantly reduced in pre-diabetic individuals, post-challenge glucose was an independent determinant of the levels of both CD34(+) and CD34(+)KDR(+) cells. CONCLUSIONS/INTERPRETATION: Glucose tolerance was negatively associated with progenitor cell levels in middle-aged healthy individuals. Depletion of endothelial progenitors with increasing fasting and post-meal glucose may be one cause of the high incidence of cardiovascular damage in individuals with pre-diabetes.     

Circulating endothelial progenitor cells correlate with erectile function in patients with coronary heart disease.

AIMS: The aim of the study was to determine the influence of endothelial progenitor cells (EPC) on erectile dysfunction (ED). EPC play a major role in repair mechanisms of the endothelial monolayer, but the role of EPC in ED is unclear. METHODS AND RESULTS: Circulating levels of CD34(+)/KDR(+) and CD133(+) EPC were determined in 119 patients with known coronary artery disease. ED was evaluated with an ED-score generated from the KEED questionnaire. Prevalence of ED was 59.7%. In univariate analysis, age, hypertension, reduced left ventricular ejection fraction (LVEF), diabetes, and circulating levels of CD133(+) EPC, but not cardiovascular drug treatment were associated with ED. Body mass index (BMI) was positively (r = 0.319, P=0.003) and high-density lipoprotein was negatively (r=-0.246, P=0.034) correlated with ED. Adjustment for age, diabetes, hypertension, BMI, smoking, LVEF, use of statins and lower urinary tract symptoms, and prior coronary intervention revealed low levels of circulating immature CD133(+) EPC as independent risk factor for ED (95% CI -11.183 to -1.7371, P=0.008). CONCLUSION: Reduced levels of circulating CD133(+) EPC are an independent risk factor for ED. Thus, EPC may be a link between cardiovascular risk factors, endothelial dysfunction, and ED.     

Fibroblast growth factor receptor-1 is expressed by endothelial progenitor cells

Recent experiments show that hematopoietic progenitor cell populations contain endothelial precursor cells. We have isolated a population of CD34(+) cells that expresses fibroblast growth factor receptor-1 (FGFR-1) and that differentiates into endothelial cells in vitro. We find that 4.5% +/- 2.1% of CD34(+) cells isolated from bone marrow, cord blood, and mobilized peripheral blood express FGFR-1 and that viable CD34(+)FGFR(+) cells are small, with little granularity, and express both primitive hematopoietic and endothelial markers on their surface. The primitive hematopoietic markers AC133, c-kit, and Thy-1 are coexpressed by 75%, 85%, and 64% of CD34(+)FGFR(+) cells, respectively. Most of the CD34(+)FGFR(+) cells also express antigens found on endothelial cells, such as CD31, vascular endothelial growth factor receptor-2, and the endothelial-specific cell surface marker, vascular endothelial cadherin (VE-cadherin), whereas 56% to 60% of the cells express Tie, Tek, and the endothelial-specific marker, P1H12. The CD34(+)FGFR(+) population is enriched in cells expressing endothelial-specific antigens compared with the CD34(+) population. Isolated CD34(+)FGFR(+) cells grow slowly in culture, are stimulated by fibroblast growth factor-2 and vascular endothelial growth factor, and give rise to cells that express von Willebrand factor and VE-cadherin and that incorporate acetylated low-density lipoprotein. These experiments show that FGFR-1 is expressed by a subpopulation of CD34(+) cells that give rise to endothelial cells in vitro, indicating that this population contains endothelial stem/progenitor cells.     

VEGFR-3 and CD133 identify a population of CD34+ lymphatic/vascular endothelial precursor cells

Human CD133 (AC133)(+)CD34(+) stem and progenitor cells derived from fetal liver and from bone marrow and blood incorporate a functional population of circulating endothelial precursor cells. Vascular endothelial growth factor receptor 3 (VEGFR-3) regulates cardiovascular development and physiological and pathological lymphangiogenesis and angiogenesis. However, the origin of VEGFR-3(+) endothelial cells (ECs) and the mechanisms by which these cells contribute to postnatal physiological processes are not known, and the possible existence of VEGFR-3(+) lymphatic or vascular EC progenitors has not been studied. Using monoclonal antibodies to the extracellular domain of VEGFR-3, we show that 11% +/- 1% of CD34(+) cells isolated from human fetal liver, 1.9% +/- 0.8% CD34(+) cells from human cord blood, and 0.2% +/- 0.1% of CD34(+) cells from healthy adult blood donors are positive for VEGFR-3. CD34(+)VEGFR-3(+) cells from fetal liver coexpress the stem/precursor cell marker CD133 (AC133). Because mature ECs do not express CD133, coexpression of VEGFR-3 and CD133 on CD34(+) cells identifies a unique population of stem and progenitor cells. Incubation of isolated CD34(+)VEGFR-3(+) cells in EC growth medium resulted in a strong proliferation (40-fold in 2 weeks) of nonadherent VEGFR-3(+) cells. Plating of these cells resulted in the formation of adherent VEGFR-3(+)Ac-LDL(+) (Ac-LDL = acetylated low-density lipoprotein) EC monolayers expressing various vascular and lymphatic endothelial-specific surface markers, including CD34, VE-cadherin, CD51/61, CD105, LYVE-1, and podoplanin. These data demonstrate that human CD34(+)CD133(+) cells expressing VEGFR-3 constitute a phenotypically and functionally distinct population of endothelial stem and precursor cells that may play a role in postnatal lymphangiogenesis and/or angiogenesis.     

Reduced number of circulating endothelial progenitors and HOXA9 expression in CD34+ cells of hypertensive patients

OBJECTIVE: Circulating endothelial progenitor cells (EPCs) differentiate into mature endothelial cells and regenerate the injured endothelium. The role of homeobox A9 (HOXA9) is critical for endothelial commitment during progenitor cell maturation, postnatal neovascularization and vascular repair. The objective of our study was to measure the expression of HOXA9 in CD34+ cells from hypertensive patients and to investigate its correlation with the number of circulating EPCs. METHODS: Thirty patients with newly diagnosed, never-treated essential hypertension and 30 age- and sex-matched normotensive controls were recruited for the study. Total RNA was extracted from peripheral CD34+ cells and quantitative real-time polymerase chain reaction for measurement of HOXA9 expression was performed. The number of CD34+/human kinase insert domain protein receptor + (KDR+) EPCs was measured and the Framingham risk estimated. RESULTS: Hypertensive patients had reduced HOXA9 expression compared to normotensive subjects (-26%, P < 0.001), and lower levels of peripheral CD34+/KDR+ EPCs (421 +/- 93 versus 582 +/- 101, P < 0.001). HOXA9 expression was inversely associated with systolic blood pressure (r = -0.54, P < 0.001) and the Framingham risk (r = -0.50, P < 0.001). A direct association was observed between the number of EPCs and HOXA9 expression (r = 0.50, P < 0.001), which was independent of blood pressure levels and Framingham risk. In a subgroup of 15 hypertensive patients, a 4-week treatment with ramipril was associated with a significant 15% increase in HOXA9 expression and 25% increase in EPC levels. CONCLUSIONS: In hypertensive patients, downregulation of HOXA9 expression in peripheral CD34+ cells may have a role in the loss of circulating EPCs, thus potentially impairing postnatal neovascularization and vascular repair.     

Circulating endothelial progenitor cell levels are higher during childhood than in adult life

Age-related vascular dysfunction contributes to the increased cardiovascular risk in elderly. Endothelial progenitor cells (EPC), a hematopoietic stem cell (HSC) subtype, can improve vascular repair. Therefore, it is hypothesized that a decrease in these circulating progenitor cells during aging plays a role in the enhanced cardiovascular risk. Until now, research has focused on EPC and HSC in the aging adult, but no studies have been conducted in children whereas animal studies specifically suggest a benefit of juvenile bone marrow. We investigated CD34(+)/KDR(+) EPC and CD34(+) HSC numbers by flow cytometry in healthy humans aged 1- to 81-years old. An inverse relation with age was observed for EPC counts [r=-0.37, p=0.007] as well as for HSC counts [r=-0.37, p=0.008]. During childhood significantly higher levels of EPC [p<0.0001] and HSC [p=0.001] were found compared to adults. These findings may have great clinical relevance since increasing circulating EPC levels is a promising therapeutic target to enhance the endogenous regenerative capacity. Better insight in the mechanisms underlying the higher EPC levels in children may provide options to increase EPC counts in adults, thereby potentiating endothelial repair mechanisms.     

Expression of VEGFR-2 and AC133 by circulating human CD34(+) cells identifies a population of functional endothelial precursors

Emerging data suggest that a subset of circulating human CD34(+) cells have phenotypic features of endothelial cells. Whether these cells are sloughed mature endothelial cells or functional circulating endothelial precursors (CEPs) is not known. Using monoclonal antibodies (MoAbs) to the extracellular domain of the human vascular endothelial receptor-2 (VEGFR-2), we have shown that 1.2 +/- 0.3% of CD34(+) cells isolated from fetal liver (FL), 2 +/- 0.5% from mobilized peripheral blood, and 1.4 +/- 0.5% from cord blood were VEGFR-2(+). In addition, most CD34(+)VEGFR-2(+) cells express hematopoietic stem cell marker AC133. Because mature endothelial cells do not express AC133, coexpression of VEGFR-2 and AC133 on CD34(+) cells phenotypically identifies a unique population of CEPs. CD34(+)VEGFR-2(+) cells express endothelial-specific markers, including VE-cadherin and E-selectin. Also, virtually all CD34(+)VEGFR-2(+) cells express the chemokine receptor CXCR4 and migrate in response to stromal-derived factor (SDF)-1 or VEGF. To quantitate the plating efficiency of CD34(+) cells that give rise to endothelial colonies, CD34(+) cells derived from FL were incubated with VEGF and fibroblast growth factor (FGF)-2. Subsequent isolation and plating of nonadherent FL-derived VEGFR-2(+) cells with VEGF and FGF-2 resulted in differentiation of AC133(+ )VEGFR-2(+) cells into adherent AC133(-)VEGFR-2(+)Ac-LDL(+ )(acetylated low-density lipoprotein) colonies (plating efficiency of 3%). In an in vivo human model, we have found that the neo-intima formed on the surface of left ventricular assist devices is colonized with AC133(+)VEGFR-2(+) cells. These data suggest that circulating CD34(+) cells expressing VEGFR-2 and AC133 constitute a phenotypically and functionally distinct population of circulating endothelial cells that may play a role in neo-angiogenesis.     

非阻塞性冠状动脉粥样硬化患者内皮功能不全的影响因素

目的探讨非阻塞性冠状动脉粥样硬化患者内皮功能不全的影响因素。方法选取2013年6月至2015年6月首都医科大学宣武医院心脏内科收治的因胸痛疑诊冠心病、经冠状动脉造影检查证实为非阻塞性冠状动脉粥样硬化症(冠状动脉狭窄<50%)的患者110例。行肱动脉血流介导内皮依赖性血管舒张功能(FMD)检测,用流式细胞仪检测外周血CD133+/KDR+、CD34+/KDR+以及CD34+/CD133+/KDR+内皮祖细胞(EPCs)。根据FMD分为对照组(FMD>10%)和内皮功能不全组(FMD≤10%)。采用SPSS 19.0软件进行统计分析。应用logistic回归模型分析影响内皮功能不全的因素。结果2组患者CD133+/CDR+、CD34+/KDR+或CD34+/CD133+/KDR+循环EPCs数量比较,差异无统计学意义(P>0.05)。多因素logistic回归分析显示,年龄是影响内皮功能不全的独立危险因素(95%CI 1.004~1.104,P=0.033)。结论非阻塞性冠状动脉粥样硬化患者内皮功能不全的独立影响因素是年龄,而非循环EPCs数量。     

Sex-dependent attenuation of plaque growth after treatment with bone marrow mononuclear cells

There are clinically relevant differences in symptomatology, risk stratification, and efficacy of therapies between men and women with coronary artery disease. Sex-based differences in plaque attenuation after administration of bone marrow mononuclear cells (BMNCs) are unknown. Forty-five male and 57 female apolipoprotein-E knockout (apoE(-/-)) mice were fed a high-fat diet. At 14 weeks of age, animals received 4 biweekly intravenous sex-matched (males, n=11; females, n=13) or -mismatched (males, n=12; females, n=14) BMNCs obtained from C57BL6/J mice. The rest of the apoE(-/-) mice were vehicle treated (males, n=13; females, n=20) or were age-matched untreated controls (males, n=9; females, n=10). Aortic plaque burden, progenitor cell profiles in bone marrow (BM) and 22 circulating cytokines/chemokines were examined 1 week following the final injection. Only female BMNCs infused into male apoE(-/-) recipients significantly decreased plaque formation (P<0.001). This reparative response univariately correlated with increased CD34(+) (P=0.02), CD45(+) (P=0.0001), and AC133(+)/CD34(+) (P=0.001) cell percentages in the BM of recipients but not with total serum cholesterol or percentage of BM-CD31(+)/CD45(low) cells. In a multivariate analysis, BM-AC133(+)/CD34(+) and BM-CD45(+) percentage counts correlated with a lower plaque burden (P<0.05). Increased granulocyte colony-stimulating factor levels highly correlated with plaque attenuation (r=-0.86, P=0.0004). In untreated apoE(-/-) mice of either sex, BM-AC133(+)/CD34(+) cells rose initially and then fell as plaque accumulated; however, BM-AC133(+)/CD34(+) percentages were higher in females at all times (P相似文献   

循环EPCs CD34^＋水平与高血压病患者心血管危险因素的关系

目的探讨能否将循环内皮祖细胞(EPCs)CD34 水平作为评价高血压病患者心血管危险度的标志。方法高血压病患者组62例,对照组20例。高血压病患者采用Framingham心血管危险因素积分分层心血管危险因素,分为低危组18例,中危组14例,高危组17例,极高危组13例。作外周血循环EPCs CD34 水平与Framingham心血管危险因素积分的相关性分析。结果各研究组高血压病患者外周循环EPCs CD34 水平随着其心血管危险程度的增加,逐步下降,各组间比较有统计学意义(P<0.05)。EPCs CD34 水平与Framingham心血管危险因素积分呈负相关关系(r=-0.875,P<0.01)。结论高血压病患者循环EPCs CD34 水平下降与心血管危险因素有显著的相关性。循环EPCs CD34 水平可以作为高血压病患者心血管危险度的标志。     

Differentiation of endothelial cells from human umbilical cord blood AC133−CD14+ cells

Endothelial progenitor cells (EPCs) participate in neovascularization and are consistent with postnatal vasculogenesis. In vitro, they differentiate into endothelial cells (ECs). Prior reports have suggested that circulating human AC133(+) cells have the capacity to differentiate into ECs as progenitor cells. However, recent studies have demonstrated that circulating CD34(-)CD14(+) cells also have EPC-like properties in vitro and in vivo. We tested whether AC133(-)CD14(+) cells from human umbilical cord blood (HUCB) have the potential to differentiate into ECs. The AC133(-)CD14(+) cells were isolated from HUCB by magnetic bead selection and cultured on fibronectin-coated six-well trays in M199 medium supplemented with fetal bovine serum (FBS), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and insulin growth factor (IGF-1). The AC133(-)CD14(+) cells adhered slightly within 1 day of culture and subsequently underwent a distinct process of morphological transformation to spindle-shaped cells that sprouted from the edge of the cell clusters. After 14 days, the cells formed cord- and tubular-like structures. The AC133(-)CD14(+) cells showed a strong increase in the endothelial marker P1H12 over time, whereas CD14 decreased, and CD45 did not change, respectively. In addition, the cells expressed endothelial markers von Willebrand's factor (vWF), platelet/endothelial cell adhesion molecule-1 (PECAM-1), vascular endothelial growth factor receptor-1 (VEGFR-1)/Flt-1, VEGFR-2/Flk-1, eNOS, and VE-cadherin, but did not express Tie-2 after 7 days of culture. The present data indicate that AC133(-)CD14(+) cells from HUCB are able to develop endothelial phenotype with expression of endothelial-specific surface markers and even form cord- and tubular-like structures in vitro as progenitor cells.     

Haematopoietic and endothelial progenitor cells are deficient in quiescent systemic lupus erythematosus

BACKGROUND: Systemic lupus erythematosus (SLE) is associated with a high prevalence of cardiovascular disease. Circulating endothelial progenitor cells (EPCs) contribute to vascular regeneration and repair, thereby protecting against atherosclerotic disease. EPCs are derived from CD34+ haematopoietic stem cells (HSCs), which have an increased propensity for apoptosis in the bone marrow of patients with SLE. AIM: To determine whether circulating HSCs and EPCs are reduced in SLE, contributing to an increased cardiovascular risk. METHODS: Progenitor cells were sampled from 15 female patients with SLE in prolonged clinical remission from their disease and 15 matched healthy controls. HSC and CD34+KDR+ EPCs were quantified by flow cytometry. Annexin V staining was used to identify apoptotic cells. RESULTS: Patients with SLE had reduced levels of circulating CD34+ HSCs and CD34+KDR+ EPCs, associated with increased HSC apoptosis. Compared with controls, the fraction of HSCs that could be identified as EPCs was higher in patients with SLE, consistent with a primary defect of HSCs. EPC outgrowth from mononuclear cells, which depends mainly on CD34- cells, was unaffected. CONCLUSIONS: Patients with SLE have lower levels of circulating HSCs and EPCs, even during clinical remission. The data suggest that increased HSC apoptosis is the underlying cause for this depletion. These observations indicate that progenitor cell-mediated endogenous vascular repair is impaired in SLE, which may contribute to the accelerated development of atherosclerosis.     

Evidence for genetic regulation of endothelial progenitor cells and their role as biological markers of atherosclerotic susceptibility.

AIMS: Endothelial progenitor cells (EPCs) are found in the peripheral circulation and are capable of endothelial repair and neovascularization. EPC number and function are reduced in subjects with cardiovascular risk factors or proven coronary artery disease (CAD). We hypothesized that EPC number and/or function may be genetically regulated and may vary in healthy adult offspring depending on parental history of CAD. METHODS AND RESULTS: We studied 102 subjects comprising 24 healthy parent-healthy offspring pairs and 27 CAD parent-healthy offspring pairs. We measured the number of circulating CD34(+)VEGFR-2(+) and AC133(+)VEGFR-2(+) EPCs, the number of EPCs grown in culture, and the migration capacity of cultured EPCs towards vascular endothelial growth factor. There was significant correlation in the number of cultured EPCs between healthy parents and their offspring (R = 0.492, P = 0.015) and CAD parents and their offspring (R = 0.751, P < 0.001). Offspring of subjects with CAD had significantly higher numbers of circulating CD34(+)VEGFR-2(+) and AC133(+)VEGFR-2(+) cells (P = 0.018 and P < 0.001, respectively). There was no difference in migration capacity between groups. CONCLUSION: Our results suggest that EPC number is, at least in part, genetically regulated. Circulating EPCs may represent biological markers of occult vascular damage in offspring with hereditary risk of CAD.     

Erythropoietin regulates endothelial progenitor cells

Circulating bone marrow-derived endothelial progenitor cells (EPCs) promote vascular reparative processes and neoangiogenesis, and their number in peripheral blood correlates with endothelial function and cardiovascular risk. We tested the hypothesis that the cytokine erythropoietin (EPO) stimulates EPCs in humans. We studied 11 patients with renal anemia and 4 healthy subjects who received standard doses of recombinant human EPO (rhEPO). Treatment with rhEPO caused a significant mobilization of CD34(+)/CD45(+) circulating progenitor cells in peripheral blood (measured by flow cytometry), and increased the number of functionally active EPCs (measured by in vitro assay) in patients (week 2, 312% +/- 31%; week 8, 308% +/- 40%; both P <.01 versus baseline) as well as in healthy subjects (week 8, 194% +/- 15%; P <.05 versus baseline). The effect on EPCs was already observed with an rhEPO dose of about 30 IU/kg per week. Administration of rhEPO increased the number of functionally active EPCs by differentiation in vitro in a dose-dependent manner, assessed in cell culture and by tube formation assay. Furthermore, rhEPO activates the Akt protein kinase pathway in EPCs. Erythropoietin increases the number of functionally active EPCs in humans. Administration of rhEPO or EPO analogs may open new therapeutic strategies in regenerative cardiovascular medicine.     

Influence of human leucocyte antigen disparity and graft lymphocytes on allogeneic engraftment and survival after umbilical cord blood transplant in adults

The dose of graft-nucleated cells and CD34(+) haematopoietic progenitor cells are predictors of allogeneic engraftment and survival in umbilical cord blood (UCB) recipients. In this single institution prospective phase II trial, flow cytometric analyses of CD34(+) progenitor and lymphocyte populations in unmodified single unit human leucocyte antigen (HLA)-disparate UCB grafts infused into 31 consecutive adults (median age 41 years, range 20-64) receiving myeloablative conditioning were compared with clinical outcomes. Median infused UCB graft-nucleated cells and CD34(+) dose was 2.2 x 10(7)/kg and 1.2 x 10(5)/kg respectively. Day to absolute neutrophil count >/=0.5 x 10(9)/l with full donor chimerism averaged 27 d (range 12-41). Univariate analyses demonstrated that UCB graft-infused cell doses of CD34(+) (P = 0.015), CD3(+) (P = 0.024) and CD34(+)HLADR(+)CD38(+) progenitors (P = 0.043) correlated with neutrophil engraftment. This same analysis did not demonstrate a correlation between CD34(+) (P = 0.11), CD3(+) (P = 0.28) or CD34(+)HLADR(+)CD38(+) (P = 0.108) cell dose and event-free survival (EFS). High-resolution matching for HLA-class II (DRB1) resulted in improved EFS (P = 0.02) and decreased risk for acute graft-versus-host disease (GVHD) (P = 0.004). Early mortality (prior to post-transplant day +28) occurred in three patients, while 26 patients achieved myeloid engraftment. These results suggest that UCB graft matching at DRB1 is an important risk factor for acute GVHD and survival, while higher UCB graft cell doses of CD34(+), committed CD34(+) progenitors and CD3(+) T cells favourably influence UCB allogeneic engraftment.     

不稳定性心绞痛患者循环内皮祖细胞与血管内皮功能的变化

目的探讨不稳定性心绞痛患者外周血循环内皮祖细胞(EPCS)与血管内皮功能的变化。方法采用高分辨率血管超声法检测30例不稳定性心绞痛患者与30例正常者作对照组肱动脉血流介导的内皮依赖性血管舒张功能(FMD)及硝酸甘油介导的非内皮依赖性血管舒张功能(NMD);流式细胞仪测定外周血中CD34+单个核细胞的水平;外周血分离单个核细胞一定条件下培养2周,免疫组织化学技术鉴定培养贴壁细胞表面标志CD34的表达;倒置荧光显微镜鉴定贴壁细胞FITC-UEA-I和DII-ACLDL双染色阳性细胞为正在分化的EPCS。结果不稳定性心绞痛组FMD明显低于对照组[(5·85±3·04)%比(8·81±4·48)%,P<0·05];NMD在两组中差异无统计学意义[(13·60±5·03)%比(14·18±4·50)%,P>0·05];CD34+细胞水平明显高于对照组[(0·13±0·05)%比(0·09±0·04)%,P<0·05];FMD与CD34+细胞水平呈负相关(R=-0·385,P<0·05)。培养的贴壁细胞免疫组化显示CD34阳性,倒置荧光显微镜显示这些贴壁细胞FITC-UEA-I和DII-ACLDL双染色阳性。结论不稳定性心绞痛患者CD34+细胞增加和血管内皮功能受损,提示循环EPCS增加可能是对急性冠状动脉缺血和内皮损伤的代偿反应。     

Smoking is associated with depletion of circulating endothelial progenitor cells and elevated pulmonary artery systolic pressure in patients with coronary artery disease

Smoking is associated with depletion of endothelial progenitor cells (EPCs) and may subsequently contribute to the development of vascular dysfunction. The aim of this study was to investigate the relation between circulating EPCs and pulmonary artery systolic pressure (PASP) as determined by flow cytometry and echocardiography in 174 patients (mean age 69 ± 9 years, 95 smokers) with established coronary artery disease. Smokers had significantly lower circulating log CD34/KDR(+) (0.86 ± 0.03 vs 0.96 ± 0.03 × 10?3/ml, p = 0.032) and log CD133/KDR(+) (0.68 ± 0.03 vs 0.82 ± 0.03 × 10?3/ml, p = 0.002) EPCs and a higher prevalence of elevated PASP >30 mm Hg (52% vs 30%, p = 0.001) than nonsmokers. Smokers with elevated PASP also had significantly lower circulating log CD34/KDR(+) (0.74 ± 0.04 vs 0.88 ± 0.06 × 10?3/ml, p <0.001) and log CD133/KDR(+) (0.61 ± 0.04 vs 0.78 ± 0.05 × 10?3/ml, p <0.001) EPCs, higher pulmonary vascular resistance, and larger right ventricular dimensions with impaired function (all p values <0.05). Log CD34/KDR(+) and log CD133/KDR(+) EPC counts were significantly and negatively correlated with PASP (r = -0.30, p <0.001, and r = -0.34, p <0.001, respectively) and pulmonary vascular resistance (r = -0.29, p = 0.002, and r = -0.18, p = 0.013, respectively). In conclusion, this study demonstrated that in patients with coronary artery disease, smoking was associated with a reduced number of EPCs and elevated PASP. This suggests that in smokers, depletion of circulating EPCs might be linked to the occurrence of pulmonary vascular dysfunction.     

Role of kinin B2 receptor signaling in the recruitment of circulating progenitor cells with neovascularization potential

Reduced migratory function of circulating angiogenic progenitor cells (CPCs) has been associated with impaired neovascularization in patients with cardiovascular disease (CVD). Previous findings underline the role of the kallikrein-kinin system in angiogenesis. We now demonstrate the involvement of the kinin B2 receptor (B(2)R) in the recruitment of CPCs to sites of ischemia and in their proangiogenic action. In healthy subjects, B(2)R was abundantly present on CD133(+) and CD34(+) CPCs as well as cultured endothelial progenitor cells (EPCs) derived from blood mononuclear cells (MNCs), whereas kinin B1 receptor expression was barely detectable. In transwell migration assays, bradykinin (BK) exerts a potent chemoattractant activity on CD133(+) and CD34(+) CPCs and EPCs via a B(2)R/phosphoinositide 3-kinase/eNOS-mediated mechanism. Migration toward BK was able to attract an MNC subpopulation enriched in CPCs with in vitro proangiogenic activity, as assessed by Matrigel assay. CPCs from cardiovascular disease patients showed low B(2)R levels and decreased migratory capacity toward BK. When injected systemically into wild-type mice with unilateral limb ischemia, bone marrow MNCs from syngenic B(2)R-deficient mice resulted in reduced homing of sca-1(+) and cKit(+)flk1(+) progenitors to ischemic muscles, impaired reparative neovascularization, and delayed perfusion recovery as compared with wild-type MNCs. Similarly, blockade of the B(2)R by systemic administration of icatibant prevented the beneficial effect of bone marrow MNC transplantation. BK-induced migration represents a novel mechanism mediating homing of circulating angiogenic progenitors. Reduction of BK sensitivity in progenitor cells from cardiovascular disease patients might contribute to impaired neovascularization after ischemic complications.     

Multiparameter flow-cytometrical quantitation of circulating CD34+-cells: correlation to the quantitation of circulating haemopoietic progenitor cells by in vitro colony-assay

A multiparameter flow-cytometrical method for the quantitation of CD34(+)-cells present in adult human peripheral blood cells (PBMC) has been developed. PBMC from 13 healthy adult subjects were analysed for CD34(+)-cells by flow-cytometry, with only the lymphoid population of cells negative for anti-CD3-moAb included in the analysis. At the same time mononuclear cells from the same individuals were depleted of CD3(+)- and CD14(+)-cells by immunomagnetic purging. These cells were cultured for haemopoietic colonies. A correlation coefficient of 0.92 was calculated by regression analysis of CD34(+)-cells number versus the numbers of colonies (CFU-GM, BFU-E). Purging with anti-CD34-moAb abrogated colony-growth. The flow-cytometrical method for the determination of circulating CD34(+)-cells was used for the determination of circulating haemopoietic progenitor cells in one patient, in order to time leukapheresis for subsequent autologous reinfusion following high-dose chemotherapy. Determination of CD34(+)-cells from human adult peripheral blood by multiparameter flow-cytometry promises to be a useful tool for monitoring circulating haemopoietic progenitor cells as identified by anti-CD34-moAb.     

Endothelial progenitor cells are reduced in refractory hypertension

Circulating endothelial progenitor cells (EPCs) play a key role in the maintenance of endothelial homoeostasis and promote vascular repair. They may also be of predictive value for cardiovascular events. Reduced EPC number and functional activity have been associated with several cardiovascular risk factors, but their relationship with hypertension remains unclear. The objective of this study was to investigate if number and function of circulating EPCs are reduced in patients with refractory hypertension (RHT). Circulating EPCs (CD34+ CD133+/CD45+) were isolated from peripheral blood by flow cytometry in 39 RHT and 30 normotensive controls. EPC number was also determined in vitro after 7 days in culture. After age adjustment, EPC concentration was significantly reduced in RHT as compared with controls (mean (95% CI), 33.8 (18.1-49.6) vs 69.1 (50.7-87.5) EPCs per 10(5) peripheral mononuclear cells (MNCs), respectively; P=0.014). After in vitro culture, EPCs were also reduced in patients as compared with controls (mean (95% CI), 142.3 (49.5-235.0) vs 611.0 (480.2-741.8) EPCs per field, respectively, P<0.001). In multiple linear regression analysis, circulating EPCs were significantly reduced by 56.3% in RHT as compared with control (P=0.006), independently of all other known risk factors. Moreover, RHT had a high independent predictive value for lower EPC proliferation. The number of EPCs per field was reduced by 76.7% in RHT with respect to controls (P<0.001). In summary, the number of circulating EPCs after culture is reduced in patients with RHT, which may be related to the increased rate of endothelial dysfunction, atherosclerotic disease and cardiovascular events observed in this population.