Department of Internal Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria.
Int J Obes (Lond). 2010 Apr;34(4):687-700. doi: 10.1038/ijo.2009.280. Epub 2010 Jan 12.
Circulating endothelial progenitor cells (EPCs), responsible for neoangiogenesis and vascular repair, negatively correlate with vascular dysfunction and atherosclerotic risk factors. Because obesity may have a crucial role in the development of endothelial dysfunction, this study evaluated the number and proliferative activity of circulating human EPCs in obese (body mass index (BMI)=48+/-9, n=45) compared with lean (23+/-2, n=45) volunteers.
EPCs were quantified after isolation of peripheral blood mononuclear cells (PBMCs) using fluorescence-activated cell sorting analyses. In addition, plated PBMCs developed colony-forming units (CFUs) from which 'outgrowth' endothelial cells (OECs) sprouted and differentiated into mature endothelial cells. Growth rates were monitored by periodical microscopic evaluation. Cell-cycle protein expression was determined by western blot analyses.
BMI negatively correlated (P<0.01) with the number of CD34(+)/CD133(+)/KDR(+) (r=-0.442), CD34(+)/KDR(+) (r=-0.500) and CD133(+)/KDR(+) (r=-0.282) EPCs. Insulin, leptin, HbA(1c), high-sensitivity C-reactive protein and hypertension, as well as diminished high-density lipoprotein and apolipoprotein A1, were not only associated with obesity but also with significantly reduced EPC levels. Applying selective culture conditions, EPC-CFUs differentiated into OECs that proliferated more slowly when derived from obese compared with lean subjects (obese: 19.9+/-2.2% vs lean: 30.9+/-3.2% grown area per week, P<0.01). The reduced proliferation was reflected by decreased (P<0.05, n=24 for each group) expression of cell-cycle-promoting cyclins and E2F-1, by hypophosphorylation of retinoblastoma protein and by increased (P<0.05, n=24 for each group) expression of the cell-cycle inhibitor p21(WAF-1/Cip1).
Reduced numbers of EPCs along with their premature senescence, as shown in this study, could function as early contributors to the development and progression of vascular dysfunction in obesity.
循环内皮祖细胞（EPCs）负责新生血管形成和血管修复，与血管功能障碍和动脉粥样硬化危险因素呈负相关。由于肥胖可能在血管内皮功能障碍的发展中起着至关重要的作用，因此本研究评估了肥胖者（体重指数（BMI）=48±9，n=45）与瘦者（23±2，n=45）志愿者外周血单个核细胞（PBMCs）中循环人 EPCs 的数量和增殖活性。
使用荧光激活细胞分选分析分离 PBMCs 后，定量 EPCs。此外，在平板 PBMCs 中形成集落形成单位（CFUs），从中“生长”出的内皮细胞（OECs）发芽并分化为成熟的内皮细胞。通过定期的显微镜评估来监测生长速度。通过 Western blot 分析确定细胞周期蛋白的表达。
BMI 与 CD34(+)/CD133(+)/KDR(+)（r=-0.442）、CD34(+)/KDR(+)（r=-0.500）和 CD133(+)/KDR(+)（r=-0.282）EPCs 的数量呈负相关（P<0.01）。胰岛素、瘦素、HbA(1c)、高敏 C 反应蛋白和高血压，以及高密度脂蛋白和载脂蛋白 A1 减少，不仅与肥胖有关，而且与 EPC 水平显著降低有关。应用选择性培养条件，EPC-CFUs 分化为 OECs，从肥胖者中分离出的 OECs增殖速度较慢，与瘦者相比（肥胖者：19.9±2.2%，每周增长面积；瘦者：30.9±3.2%，P<0.01）。增殖减少反映在细胞周期促进细胞周期蛋白和 E2F-1 的表达减少（每组 P<0.05，n=24），视网膜母细胞瘤蛋白的低磷酸化以及细胞周期抑制剂 p21(WAF-1/Cip1)的表达增加（每组 P<0.05，n=24）。
本研究表明，EPCs 数量减少及其衰老提前，可能是肥胖患者血管功能障碍发展和进展的早期原因。
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