Effects of statins on endothelium and their contribution to neovascularization by mobilization of endothelial progenitor cells

Statins are potent drugs with a variety of cardiovascular protective effects which appear to occur independent of cholesterol reduction. The vasculoprotective effects of statins might be due to their direct effect on endothelial cells leading to improved nitric oxide (NO) bioavailability. Mechanistically, statins induce endothelial nitric oxide synthesis (eNOS) mRNA stability in endothelial cells and promote eNOS activity through a PI3K/Akt dependent pathway. Novel targets of statins are pro-angiogenic actions including the mobilization and differentiation of bone marrow derived endothelial progenitor cells, which accelerate angiogenesis or re-endothelialization. The functional improvement and increased homing capacity of endothelial progenitor cells induced by statin treatment might reverse impaired functional regeneration capacities seen in patients with risk factors for coronary artery disease or documented active coronary artery disease.     

Beneficial effects of statins on endothelial progenitor cells

ABSTRACT:: In recent years, endothelial progenitor cells (EPCs) have been demonstrated to play an important role during tissue vascularization and endothelium homeostasis in adults. In addition, EPCs have been implicated in the pathophysiology of cardiovascular and cerebrovascular disease, such that a decreased number of EPCs may not only be a risk indicator but also a potential therapeutic target. Of the many agents that have been examined to increase EPCs and enhance their function, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors or statins are one of the most intriguing. Accumulated evidence has demonstrated that statins promote EPC mobilization, proliferation, migration, adhesion, differentiation and reduce senescence and apoptosis independent of their serum lipid-lowering effect. This review summarizes the understanding of current mechanisms explaining the myriad of beneficial effects of statins on EPCs and discusses future challenges for studies involving statins and subpopulations of EPCs. However, the pharmacologic mechanisms of action of statins on EPCs remain at the cellular level, whereas the putative molecular mechanisms await further studies.     

Effects of myocardial postconditioning on the recruitment of endothelial progenitor cells

Background: Ischemic postconditioning (PostC), brief repetitive cycles of ischemia and reperfusion during early reperfusion, is suggested to protect the myocardium in patients with stent thrombosis‐elevation myocardial infarction (STEMI) by improved endothelial dysfunction and alteration of cytokine release. These mechanisms are also of importance for the recruitment of endothelial progenitor cells (EPC), an endogenous repair mechanism for re‐endothelialization and neoangiogenesis. The aim of this study was to investigate the effect of PostC on recruitment of EPC. Methods: EPC were analyzed in 20 patients with STEMI randomized to receive four cycles of PostC following percutaneous coronary intervention (PCI) or conventional PCI. Different subpopulations of EPC were quantified immediately and on day 4 using flow cytometry. Myocardium at risk, and infarct size was determined by cardiovascular magnetic resonance. Results: There was no influence of PostC on the number of different EPC (CD34⁺, CD133⁺, CD34⁺CD133⁺, CD34⁺KDR⁺, CD34^?CD133⁺KDR⁺, CD34⁺CD133⁺KDR⁺). Left ventricular ejection fraction, myocardium at risk, and infarct size did not correlate to the mobilization of EPC. There was an inverse correlation between the symptom‐to‐balloon time and the mobilization of progenitor precursor cells (CD34⁺ cells: R =?0.527, P = 0.02; CD133⁺ cells: R =?0.624, P = 0.004; CD34⁺CD133⁺ cells: R =?0.466, P = 0.04). Discussion: Ischemic PostC did not result in improved mobilization of EPC in STEMI patients. The recruitment of progenitor cells seems to be related to the duration of ischemia rather than the size of the ischemic myocardial area. More effort is needed to understand the changes of endothelial surface markers by PostC and their role in EPC recruitment and homing. (J Interven Cardiol 2012;25:103–110)     

他汀类药物对外周血内皮祖细胞数量和功能的影响

目的　观察氟伐他汀和辛伐他汀对外周血内皮祖细胞 (endothelialprogenitorcell,EPC)的影响。方法　采用密度梯度离心法从外周血获取单个核细胞 ,将其接种在人纤维连接蛋白包被培养板 ,培养 7d后 ,收集贴壁细胞 ,加入不同浓度氟伐他汀 (分别为 0 0 1、0 1、1 0、10 μmol/L)和辛伐他汀 (1 0 μmol/L)培养一定的时间 (6、12、2 4h和 4 8h)。激光共聚焦显微镜鉴定FITC UEA Ⅰ和DiI acLDL双染色阳性细胞为正在分化的EPC ,并在倒置荧光显微镜下计数。然后分别采用MTT比色法、改良的Boyden小室和黏附能力测定实验来观察EPC的增殖能力、迁移能力和黏附能力。结果　氟伐他汀显著增加外周血EPC数量 ,并且EPC数量随氟伐他汀浓度增加及作用时间延长而增加 ,1 0 μmol/L浓度氟伐他汀作用 2 4h对EPC数量的影响最为显著 (较对照组增加了 1 5倍 ,P <0 0 5 )。氟伐他汀和辛伐他汀也显著改善了外周血EPC的黏附能力、迁移能力和增殖能力。相同浓度的氟伐他汀和辛伐他汀 (1 0 μmol/L)对EPC数量和功能的影响无显著性差异 (P >0 0 5 )。结论结果提示他汀类药物可增加EPC的数量且伴随着EPC功能的改善。     

Effects of haemodialysis on circulating endothelial progenitor cell count

During haemodialysis (HD) the endothelium is the first organ to sense and to be impaired by mechanical and immunological stimuli. We hypothesized that a single HD session induces mobilization of endothelial progenitor cells (EPCs) and that cardiovascular risk factors may influence this process. We quantified EPCs at different maturational stages (CD34+, CD133+/VEGFR2+) in blood samples from 30 patients, during HD and on the interdialytic day, and in 10 healthy volunteers. Samples were drawn at the start of HD, 1, 2 and 3 h after, at the end of HD and at 24 h on the interdialytic day. Patients were divided into two groups based on a recent risk scoring system (SCORE project): low-risk (LR) and high-risk groups (HR). HD patients showed a significantly reduced basal number of EPCs with respect to healthy volunteers. In contrast, we observed increasing EPCs during HD whereas they diminished on the interdialytic day. The EPC number was directly correlated with HD time progression. The EPC number during HD was increased in the HR group with respect to the LR group. We had a direct correlation between risk score and number of EPCs. Cardiovascular risk factors influenced the mobilization of stem cells from the bone marrow. This feature could be the direct consequence of an augmented request of stem cells to respond to the most important endothelial impairment but could also show a defective capacity of EPCs to home in and repair the sites of vascular injury.     

内皮型一氧化氮合酶对内皮祖细胞生物学功能的影响

一氧化氮(NO)及一氧化氮合酶(NOS)参与调节机体多种生理活动,在心血管系统中的作用亦倍受重视.近年来,内皮型一氧化氮合酶(eNOS)的又一生物学作用已引起人们的关注.本文探讨了eNOS在内皮祖细胞的动员、分化和归巢中的作用,及其促进内皮祖细胞的生物学功能.     

C反应蛋白对内皮祖细胞部分生物学功能的影响及其机制的实验研究

目的 观察C反应蛋白(CRP)对体外培养骨髓源性内皮祖细胞(EPC)数量及增殖、迁移、黏附功能的影响及其机制探讨. 方法 密度梯度离心法获取骨髓单个核细胞,FITC-荆豆凝集紊I、DiI-乙酰化低密度脂蛋白荧光双染鉴定.单个核细胞培养7 d后进行实验分组,分为对照组和CRP干预组.CRP干预组加入不同浓度CRP(分别为5、10、15、20 μg/ml)培养48 h,然后分别采用四氮唑溴盐比色法、改良的Boyden小室和黏附能力测定来观察EPC的增殖、迁移和黏附能力.RT-PCR检测不同浓度下CRP对EPC内皮型一氧化氮合酶(eNOS)mRNA的影响,并检测EPC的NOS活性. 结果 CRP(分别为5、10、15、20 μg/ml)各组EPC数量分别为(58±3)、(54±3)、(47±3)和(39±5)个,对照组EPC数量为(60±3)个.MTT法检测CRP各亚组EPC在490 nm吸光度值分别为0.332±0.003、0.297±0.036、0.273±0.013和0.259±0.035,对照组为0.345±0.014.CRP浓度为10、15、20μ/ml 3个亚组EPC的数量及增殖能力显著低(P＜0.01).CRP各组(10、15、20 μg/ml)与对照组相比EPC黏附数量明显低[(28±2)、(22±3)、(19±3)和(16±2)个比(30±2)个,P＜0.05].不同浓度CRP各组与对照组相比EPC迁移数量明显低[(11±2)、(9±2)、(6±2)和(5±1)个比(12±2)个,P＜0.05].CRP各亚组(5、10、15、20μg/ml)EPC eNOS mRNA相对光密度显著低于对照组.CRP呈剂量依赖性降低EPC NOS活性,CRP各组EPC的NOS活性分别为(66.29±1.81)、(57.44±3.25)、(48.37±3.86)和(36.82±4.89)nmol/mg蛋白,对照组EPC NOS活性为(68.56±2.82)nmol/mg蛋白,其中浓度为10、15、20μg/ml CRP组与对照组比较差异有统计学意义(P＜0.01). 结论 CRP可能通过影响EPC eNOS表达活性降低EPC数量并影响其部分生物学功能.     

阿司匹林对内皮祖细胞功能及其诱导型一氧化氮合酶的影响

目的:观察阿司匹林对外周血内皮祖细胞(endothelial progenitor cells,EPCs)数量和功能的影响. 方法:采用密度梯度离心法从外周血获得单个核细胞,将其接种在人纤维连接蛋白包被的培养板上,培养7d后收集贴壁细胞,分别加入不同浓度阿司匹林(分别为1、2、5、10 mmol/L)培养3、6、12、24 h.激光共聚焦显微镜鉴定FITC-UEA-I和Dil-acLDL双染色阳性细胞为正在分化的EPCs,将其在倒置荧光显微镜下计数.然后分别采用MTT比色法、改良的Boyden小室、黏附能力测定实验和体外血管形成试剂盒来观察EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,免疫印迹杂交法(Western blot)半定量测定诱导型一氧化氮合酶(iNOS)含量. 结果:阿司匹林能减少外周血EPCs数量,并且EPCs数量随阿司匹林浓度和作用时间增加而减少.EPCs的增殖能力、迁移能力、黏附能力、体外血管形成能力和iNOS含量亦随阿司匹林浓度和作用时间增加而降低. 结论:阿司匹林通过减少EPCs中iNOS含量,降低EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,从而抑制内皮细胞的生成.     

阿司匹林对内皮祖细胞功能及其诱导型一氧化氮合酶的影响

目的:观察阿司匹林对外周血内皮祖细胞(endothelial progenitor cells,EPCs)数量和功能的影响。方法:采用密度梯度离心法从外周血获得单个核细胞,将其接种在人纤维连接蛋白包被的培养板上,培养7d后收集贴壁细胞,分别加入不同浓度阿司匹林(分别为1、2、5、10mmol/L)培养3、6、12、24h。激光共聚焦显微镜鉴定FITC-UEA-I和Dil-acLDL双染色阳性细胞为正在分化的EPCs,将其在倒置荧光显微镜下计数。然后分别采用MTT比色法、改良的Boyden小室、黏附能力测定实验和体外血管形成试剂盒来观察EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,免疫印迹杂交法(Western blot)半定量测定诱导型一氧化氮合酶(iNOS)含量。结果:阿司匹林能减少外周血EPCs数量,并且EPCs数量随阿司匹林浓度和作用时间增加而减少。EPCs的增殖能力、迁移能力、黏附能力、体外血管形成能力和iNOS含量亦随阿司匹林浓度和作用时间增加而降低。结论:阿司匹林通过减少EPCs中iNOS含量,降低EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,从而抑制内皮细胞的生成。     

Effects of an ARB on endothelial progenitor cell function and cardiovascular oxidation in hypertension

BACKGROUND: Angiotensin II (Ang II) receptor blocker (ARB) has been reported to have protective effects on the cardiovascular system independent of blood pressure reduction. Endothelial progenitor cells (EPCs) play a significant role in neovascularization of ischemic tissue. The average lifespan of EPCs was recently reported to be shortened by oxidative stress and regulated by anti-oxidative mechanisms. It has been reported that EPCs are present in peripheral blood and have the ability to repair cardiovascular damage. We investigated the effects of an ARB, candesartan, on EPC function and cardiovascular oxidation in salt-loaded, stroke-prone, spontaneously hypertensive rats (SHR-SP) in vivo. METHODS: Salt-loaded SHR-SP were treated with candesartan (1 mg/kg/day), a diuretic (trichlormethiazide, TCM, 1.6 mg/kg/day), or an antioxidant (tempol, 5 mg/kg/day) for 2 weeks. Peripheral blood mononuclear cells (MNCs) were isolated and cultured to assay EPC colony formation and migration. Oxidative stress in EPCs was evaluated by thiobarbituric acid reactive substance (TBARS) assay. We evaluated messenger RNA (mRNA) expression of c-kit in the heart, the renin-angiotensin system (RAS) in EPC colonies, and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit in cardiovascular organs. RESULTS: Candesartan and tempol, but not TCM, markedly increased EPC colony number in SHR-SP and reduced TBARS. Candesartan also significantly decreased mRNA expression of NADPH oxidase subunits in cardiovascular organs and increased cardiac c-kit mRNA expression. EPCs expressed mRNAs of renin, cathepsin D, chymase, and Ang II type 1 and type 2 receptors. CONCLUSIONS: Candesartan, an ARB, improves EPC dysfunction and increases cardiac c-kit expression through the anti-oxidative mechanism in hypertension. The local RAS induces oxidative stress and regulates the EPC functions.     

姜黄素对内皮祖细胞功能及内皮型一氧化氮合酶的影响

目的观察姜黄素对体外培养的人外周血内皮祖细胞（EPCs）数量及功能的影响。方法采用贴壁选择法培养人外周EPCs,培养6 d后,收集贴壁细胞并加入姜黄素（0、5、10、15μmol/L）培养一定时间（6、12、24和48 h）。荧光显微镜鉴定EPCs,分别观察EPCs的体外增殖、黏附、迁移、体外血管生成能力。Griess法检测NO分泌量,并RT-PCR半定量测定eNOS基因表达。结果姜黄素增加外周血EPCs的数量,改善EPCs的体外增殖、黏附、迁移、体外血管生成能力（P<0.01）。并上调eNOS基因表达,促进EPCs来源的NO的释放（P<0.01）。结论姜黄素增加体外EPCs数量及改善其功能,上调eNOS基因表达并增加EPCs来源的NO分泌。     

Platelets and stromal cell-derived factor-1 in progenitor cell recruitment

Stromal cell-derived factor-1 (SDF-1) is a CXC chemokine that binds to its sole counterreceptor, CXCR4. It is well reported that the SDF-1/CXCR4 signaling pathway is of vital importance to human development and to various pathophysiological phenomena, including hematopoiesis, angiogenesis, atherosclerosis, cancer growth, metastasis, and human immunodeficiency virus infection. SDF-1 promotes mobilization of bone marrow-derived endothelial progenitor cells (EPCs) to the circulation in response to vascular injury. Recently, we found that platelets express and release SDF-1 into the microcirculation upon activation and we observed that platelet-derived SDF-1 is functionally involved in recruitment of EPCs to arterial thrombi in vivo. This review discusses the unique functions of this chemokine and the newly discovered impact of platelet-derived SDF-1 into the recruitment of progenitor cells to vascular injury areas, and its subsequent effects in atherosclerosis, vascular repair, and angiogenesis.     

血管内皮祖细胞的研究进展

Asahara等1997年首次在Science杂志提出血管内皮祖细胞（endothelial progenitor cell,EPC）以来,有关EPC的研究日益增多。EPC是血管内皮细胞的前体细胞,又称为血管母细胞（angioblast）,不仅参与胚胎血管生成,而且最近几年研究发现,EPC也参与出生后的血管发生过程,提示它在缺血性疾病、防止血管再狭窄、血管创伤愈合等过程中的重要治疗作用和广阔的临床应用前景。本就目前有关EPC的来源、发育分化、动员与归巢及其应用研究作一综述。     

Involvement of E-selectin in recruitment of endothelial progenitor cells and angiogenesis in ischemic muscle

E-selectin plays critical roles in tethering leukocytes to endothelial cells (ECs). We studied the role of E-selectin in endothelial progenitor cell (EPC) homing and vasculogenesis. After ischemia, the expression of E-selectin on ECs peaked 6 to 12 hours and returned to baseline at 24 hours, whereas the level of soluble E-selectin (sE-selectin) in serum increased over 24 hours and remained high at day 7. Mouse bone marrow-derived EPCs expressed not only E-selectin but also its ligand. Homing of circulating EPCs to ischemic limb was significantly impaired in E-selectin knock-out mice, as well as wild-type mice pretreated with blocking antibody against E-selectin, which was rescued by local sE-selectin injection. Mechanism for this is that sE-selectin stimulated not only ECs to express ICAM-1, but also EPCs to secrete interleukin-8 (IL-8), leading to enhanced migration and incorporation to ECs capillary formation. In therapeutic aspect, local treatment with sE-selectin enhanced efficacy of EPC transplantation for vasculogenesis and salvage of ischemic limb. Conversely, when E-selectin was knocked down by E-selectin small interfering RNA, blood flow recovery after EPC transplantation was significantly impaired. But this impaired vasculogenesis was rescued by sE-selectin. In conclusion, these data demonstrate E-selectin is a pivotal molecule for EPCs' homing to ischemic limb and vasculogenesis.     

缺氧对糖尿病血管内皮祖细胞的影响

血管内皮的损害和再生对维持血管的完整性十分重要,血循环中骨髓来源的血管内皮祖细胞有助于血管内皮的修复.局部缺血后,血管内皮祖细胞从骨髓动员到血液中,然后归巢到缺血组织处,在缺血处通过旁分泌生长因子或者渗入血管来促进新生血管形成.糖尿病患者的血管内皮祖细胞在缺氧条件下,功能受到损害,包括动员、附着、迁移、增殖等一系列环节...