HMG-CoA reductase inhibitors (statins) increase endothelial progenitor cells via the PI 3-kinase/Akt pathway

HMG-CoA reductase inhibitors (statins) have been developed as lipid-lowering drugs and are well established to reduce morbidity and mortality from coronary artery disease. Here we demonstrate that statins potently augment endothelial progenitor cell differentiation in mononuclear cells and CD34-positive hematopoietic stem cells isolated from peripheral blood. Moreover, treatment of mice with statins increased c-kit(+)/Sca-1(+)--positive hematopoietic stem cells in the bone marrow and further elevated the number of differentiated endothelial progenitor cells (EPCs). Statins induce EPC differentiation via the PI 3-kinase/Akt (PI3K/Akt) pathway as demonstrated by the inhibitory effect of pharmacological PI3K blockers or overexpression of a dominant negative Akt construct. Similarly, the potent angiogenic growth factor VEGF requires Akt to augment EPC numbers, suggesting an essential role for Akt in regulating hematopoietic progenitor cell differentiation. Given that statins are at least as potent as VEGF in increasing EPC differentiation, augmentation of circulating EPC might importantly contribute to the well-established beneficial effects of statins in patients with coronary artery disease.     

Therapeutic angiogenesis with bone marrow--derived stem cells

Despite that advances in medical treatment and interventional procedures have reduced the mortality rate in patients with coronary artery disease, the number of patients with refractory myocardial ischemia and congestive heart failure is rapidly increasing. Experimental studies have demonstrated that bone marrow (BM) contains adult stem cells that can induce neovascularization and improve heart function in ischemic myocardium. Recent insights into the understanding of the mechanisms involved in proliferation, recruitment, mobilization, and incorporation of BM-derived stem cells into the myocardium and blood vessels have prompted development of cellular transplantation therapy for heart diseases refractory to conventional therapy. Initial preliminary clinical studies indicated potential clinical benefit of BM therapy in patients with acute myocardial infarction and chronic myocardial ischemia. Nevertheless, many obstacles remain, such as long-term safety and optimal timing and treatment strategies for BM cell therapy, and these issues need to be addressed in rationally designed, randomized clinical trials.     

Lovastatin: an HMG-CoA reductase inhibitor for lowering cholesterol

Increased levels of cholesterol, LDL-cholesterol, and VLDL-cholesterol are known risk factors for the development of coronary artery disease. There are multiple drugs that can be used for lowering cholesterol, including lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme step in cholesterol synthesis in the body. The pharmacology of this novel agent is discussed in this article.     

全骨髓培养法扩增小鼠内皮祖细胞

背景：对于小型实验动物,通过分离骨髓单个核细胞进行内皮祖细胞培养、扩增的方法较为繁琐。目的：探讨采用全骨髓培养方式扩增小型动物内皮祖细胞的可行性。方法：采用全骨髓培养分离C57BL/6小鼠内皮祖细胞,培养第7天行DiL-acLDL和FITC-UEA-1双荧光染色检测,并利用流式细胞仪检测其CD34、FLK-1表达情况。同时检测其体外血管生成能力,黏附、增殖和迁移能力。设立骨髓单个核细胞培养法为对照。结果与结论：全骨髓培养至第2天便可见早期内皮祖细胞集落形成,第7天时可见大量短梭状内皮祖细胞,其具有吞噬DiL-acLDL及结合FITC-UEA-1的能力,内皮祖细胞在基质胶上同样能够形成血管样结构,培养至第2周晚期内皮祖细胞集落出现,迅速生长形成典型的铺路石样,并能够在体外传代培养,细胞数量、细胞表面CD34、FLK-1表达、体外黏附、增殖和迁移能力及晚期集落出现时间与对照组差异无显著性意义（P〉0.05）。说明采用全骨髓培养的方式能够实现小型动物内皮祖细胞的筛选扩增,且操作简便。     

Dyslipidemias and HMG-CoA reductase inhibitor prescription in heart transplant recipients

BACKGROUND: The treatment of dyslipidemias in orthotopic heart transplant (OHT) recipients is not highlighted in the National Cholesterol Education Program Adult Treatment Panel guidelines. Emerging data suggest that hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) safely reduce the risk of transplant rejection and coronary artery vasculopathy in OHT patients. OBJECTIVE: To assess the proportion of patients from our institution reaching the low-density lipoprotein cholesterol (LDL-C) target of <100 mg/dL, evaluate the impact of statins in reaching this goal, and evaluate the prescribing practice for statins in US OHT centers. METHODS: The management of dyslipidemia of OHT recipients followed at our institution was retrospectively evaluated. In addition, the use of statins in adult OHT centers in the US that performed >or=15 OHTs per year was assessed through a survey. RESULTS: Of the 328 patients from our institution, 58.5% achieved an LDL-C <100 mg/dL. Patients prescribed statins were more likely to reach this goal (p < 0.01). A total of 85.0% of centers responding to the survey use statins as a part of their post-OHT protocol, primarily to reduce coronary artery vasculopathy (70.6%). CONCLUSIONS: Due to the potential for improved outcomes, a large proportion of patients are prescribed a statin. Our results support previous findings that statins are safe and effective in reducing LDL-C in the management of dyslipidemias in OHT recipients. Nonetheless, dyslipidemias are suboptimally managed in many post-OHT patients.     

Pharmacologic characteristics of rosuvastatin,a new HMG-CoA reductase inhibitor

Rosuvastatin is a new synthetic statin that produces a more potent and prolonged inhibition of HMG-CoA reductase than any of the other statins currently available. It is also characterised by a very low lipophilicity, which is close to that of pravastatin, and by a high hepatic selectivity. Rosuvastatin is not extensively metabolised, with little or no transformation by the different isoenzymes of cytochrome P450. It is mainly eliminated in the faeces, with an elimination half-life in humans of between 13 and 21 hours. In patients with hypercholesterolaemia, rosuvastatin was associated with large dose-dependent reductions in low density lipoprotein (LDL)-cholesterol, by 50.5% at a dose of 10 mg/day and up to 64.8% at a dose of 80 mg. Each doubling of the dose of rosuvastatin results in an additional 4.5% decrease in blood LDL-cholesterol. In phase III studies, rosuvastatin decreased LDL-cholesterol significantly more than atorvastatin, pravastatin and simvastatin. Compared with the other statins, the decrease in triglyceride levels was similar and the increase in high density lipoprotein-cholesterol was more marked, with a significant difference in most cases. To date, there has not been an excess of adverse reactions, especially liver or muscle problems, compared with the reference statins. The safety of rosuvastatin can only be definitively established in post-marketing surveys.     

绵羊骨髓来源内皮祖细胞的培养与鉴定

背景:当今,组织工程化静脉瓣的研究刚刚起步,种子细胞的选择是其关键,内皮祖细胞可以作为组织工程化静脉瓣体外构建理想的种子细胞.目的:通过体外培养与鉴定绵羊骨髓来源内皮祖细胞,探讨绵羊骨髓来源内皮祖细胞培养方法,为绵羊组织工程静脉瓣种子细胞选择提供实验基础.方法:绵羊骨髓经条件培养基进行选择培养获取骨髓单个核细胞,传代扩增后用磁珠分选出CD133+细胞再培养,流式细胞检测确认分前细胞CD133的表达情况;分选传代后绘制细胞生长曲线观察细胞生长能力,用免疫细胞化学检测细胞特异性分了CD133,D34,VWF的表达情况;FITC标记BS-1-Lectin和Dil标记ac-LDL标记细胞检测细胞吞噬功能.结果与结论:绵羊骨髓单个核细胞原代培养2 d细胞开始贴壁,7 d细胞完全融合,传代后第2天进入对数生长期,传代3～5 d形成为典型的铺路石样,传代后第7 d细胞进入增殖平台期;细胞传代后磁珠分选率为12.6%,流式细胞仪检测显示CD133阳性率为12.64%:免疫细胞化学检测显示细胞呈CD133、CD34、血管性血友病因子阳性表达.细胞能同时吞噬FITC-labeledBS-1-lectin,Dil-ac-LDL阳性率达85.3%.证实实验成功地从绵羊骨髓单个核细胞中分离培养出内皮祖细胞.     

小鼠内皮祖细胞的培养和移植

背景:内皮祖细胞移植在缺血性心脑血管疾病、创伤愈合等血管类疾病的治疗中展现出广泛的应用前景,目前内皮祖细胞在肺部疾病的研究还比较少.目的:分离和诱导培养骨髓来源的内皮祖细胞,并进行鉴定;经气管移植,观察内皮祖细胞的定位.设计、时间及地点:细胞体外培养和体内移植实验,于2008-05/2009-04在中南大学湘雅二医院中心实验室完成.材料:6周龄C57BL/6J小鼠17只,随机数字表法分为5只供体,10只受体,2只供细胞双荧光染色、免疫细胞化学实验.方法:冲洗小鼠长骨骨髓,用密度梯度离心法收集单个核细胞层,内皮细胞培养液EGM-2MV培养,观察细胞形态,将培养第7天内皮祖细胞与Dil标记的乙酰化低密度脂蛋白37℃孵育4 h,以检测内皮祖细胞对Dil-乙酰化低密度脂蛋白的摄取,再用20 g/L多聚甲醛固定细胞10 min,固定后用PBS浸洗,将FITC标记的凝集素Ⅰ加入上述标本,37℃孵育1 h,PBS浸洗,通过激光共聚焦显微镜鉴定FITC-凝集素Ⅰ和Dil-乙酰化低密度脂蛋白.主要观察指标:将标记CM-Dil的内皮祖细胞经气管注入小鼠体内,10 d后观察其在体内的定位.免疫组织化学方法检测细胞血管性血友病因子阳性率.移植后内皮祖细胞在体内的定位.结果:贴壁细胞呈现类圆形、纺锤形或多边形,7～14 d可见部分贴壁细胞生长呈"铺路石"样外观.胞浆摄取Dil-乙酰化低密度脂蛋白,显示红色,胞膜结合FITC-凝集素Ⅰ,显示绿色,双染色阳性细胞为黄色,为正在分化的内皮祖细胞,双阳性细胞达90%以上,血管性血友病因子阳性率90%以上.经气管移植后标记CM-Dil的内皮祖细胞可定位至肺内气管、血管及肾、脾血管.结论:用密度梯度离心法在EGM-2MV培养体系下可以获得较高纯度的内皮祖细胞,该细胞气管移植后可定位至肺内气管、血管及肾、脾血管.     

Chronic creatine kinase elevation not associated with HMG-CoA reductase inhibitor treatment

OBJECTIVE: To report a case of chronically elevated creatine kinase (CK) concentration that is possibly associated with renal insufficiency and prostatic carcinoma. The goal is to raise awareness among clinicians who monitor CK concentrations in patients receiving hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. CASE SUMMARY: Because of an elevated CK concentration, a 64-year-old African-American man with a history of chronic heart disease and renal insufficiency was assessed for possible myositis relating to his treatment with HMG-CoA reductase inhibitors. However, an association between the elevated enzyme concentration and drug treatment could not be clearly established. The patient was subsequently diagnosed with prostatic cancer and underwent a radical retropubic prostatectomy. The CK enzyme concentration declined following the surgery despite continuation of the drug therapy. DISCUSSION: CK is relatively nonspecific because of its wide distribution in human tissues. Although several findings of elevated CK concentrations, particularly the CK-BB isoenzyme, in patients with carcinoma or chronic renal insufficiency have been documented, these may not be common knowledge among clinicians. This case report provides an example of an unusually high CK enzyme concentration that may be linked to prostatic carcinoma and renal insufficiency. CONCLUSIONS: It is important to be aware of different causes for CK enzyme concentration elevation, especially when it is used as a monitoring parameter during HMG-CoA reductase inhibitor treatment. In a case of persistent elevated CK enzyme concentration without evidence of myositis, renal insufficiency may be a contributing factor and malignancy must be ruled out.     

Clinical rationale for rosuvastatin, a potent new HMG-CoA reductase inhibitor

Coronary heart disease (CHD) is the leading cause of death worldwide, and effective treatment of hyperlipidaemia can prevent development of CHD and significantly reduce the risk for cardiovascular events and mortality in this disease. The advent of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) has revolutionised the treatment of hyperlipidaemia, but many patients receiving these drugs still do not achieve their therapeutic goals. Rosuvastatin (Crestor; formerly ZD4522) is a new, potent and long-lasting inhibitor of HMG-CoA reductase that is highly selective for hepatocytes. Its pharmacokinetics permit once-daily dosing, and a lack of oxidative hepatic metabolism results in a reduced potential for drug-drug interactions. Preliminary clinical results indicate that it produces rapid dose-related reductions in total cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoprotein B that may exceed those achieved with other currently available statins. Increases in high-density lipoprotein cholesterol have also been observed. Rosuvastatin is also well tolerated, with no evidence of either hepato- or myotoxicity. It is hoped that new agents such as rosuvastatin may help to reduce the high global morbidity, mortality and associated costs of CHD and related vascular disorders.     

吡格列酮促进大鼠骨髓内皮祖细胞的增殖

背景：内皮祖细胞具有增殖、迁移和分化为内皮细胞的特征,对冠状动脉硬化性心脏病及糖尿病心血管并发症的发生、发展可能起着重要作用。目的：探讨选择性过氧化物酶体增殖物激活受体γ激动剂吡格列酮对大鼠骨髓内皮祖细胞增殖的影响及相关机制。方法：①采用密度梯度离心法和差速贴壁法培养大鼠骨髓内皮祖细胞,置于含0,1,10,50,100,200μmol/L吡格列酮的培养基中培养,观察吡格列酮促进内皮祖细胞增殖的最佳浓度。②将培养7d的内皮祖细胞随机分5组：对照组加含二甲基亚砜的培养液;吡格列酮组加入50μmol/L吡格列酮;PPAR-γ拮抗剂组加入50μmol/L吡格列酮及10μmol/L过氧化物酶体增殖物激活受体γ拮抗剂GW9662;PI3K/Akt阻滞剂组加入50μmol/L吡格列酮及50μmol/L磷脂酰肌醇3-激酶/蛋白激酶B通道阻滞剂Wortmannin;ERK阻滞剂组加入50μmol/L吡格列酮及20μmol/L细胞外调节蛋白激酶通道阻滞剂PD98059,观察不同组内皮祖细胞的增殖情况。结果与结论：倒置显微镜下见培养前4d细胞增殖不明显,第5-10天迅速增殖,并可见细胞集落及线状结构形成,第10天可达80%融合。培养第7天的内皮祖细胞具有吞噬Dil标记的乙酰化低密度脂蛋白和FITC标记的荆豆凝集素1的功能。10-200μmol/L的吡格列酮均可明显促进内皮祖细胞的增殖（P〈0.01）,以50μmol/L吡格列酮的作用最明显。进一步阻断相关信号通路发现,Wortmannin和GW9662可明显拮抗吡格列酮的促细胞增殖作用,而PD98059对吡格列酮的作用无影响。说明吡格列酮促进大鼠骨髓内皮祖细胞增殖的作用是通过磷脂酰肌醇3-激酶/蛋白激酶B信号通路介导的。     

血管内皮祖细胞/骨髓间充质干细胞复合细胞膜片的构建

背景：研究发现充足的血供是骨组织修复与再生必不可少的条件。
　　目的：应用血管内皮祖细胞与骨髓间充质干细胞构建出复合细胞膜片。
　　方法：体外分离培养SD大鼠血管内皮祖细胞及骨髓间充质干细胞,将两种细胞直接共培养,经成膜诱导10 d后构建出复合细胞膜片并对获得的膜片进行大体、倒置显微镜及苏木精-伊红染色观察。将血管内皮祖细胞及骨髓间充质干细胞分别应用荧光标记液标记后,观察膜片诱导过程中两种细胞的分布及交流情况。对复合细胞膜片进行碱性磷酸酶活性检测及茜素红染色,观察其成骨分化能力。
　　结果与结论：血管内皮祖细胞与骨髓间充质干细胞直接共培养成膜诱导10 d后可成功获得复合细胞膜片,两种细胞在成膜诱导过程中存在细胞间接触。获得的膜片由多层细胞及细胞外基质构成,经碱性磷酸酶活性检测及茜素红染色结果证实该膜片具有较强的成骨分化能力,为进一步将血管内皮祖细胞/骨髓间充质干细胞复合细胞膜片应用于骨缺损的修复提供了条件。     

Defining human endothelial progenitor cells

Summary.  There is no specific marker to identify an endothelial progenitor cell (EPC) and this deficiency is restricting the ability of an entire field of research in defining these cells. We will review current methods to define EPC in the human system and suggest approaches to define better the cell populations involved in neoangiogenesis. PubMed was used to identify articles via the search term 'endothelial progenitor cell' and those articles focused on defining the term were evaluated. The only human cells expressing the characteristics of an EPC, as originally proposed, are endothelial colony forming cells. A variety of hematopoietic cells including stem and progenitors, participate in initiating and modulating neoangiogenesis. Future studies must focus on defining the specific hematopoietic subsets that are involved in activating, recruiting, and remodeling the vascular networks formed by the endothelial colony forming cells.     

大鼠骨髓内皮祖细胞的分离培养与鉴定

背景：内皮祖细胞参与血管新生,但其分离、培养、鉴定方法目前并不统一。目的：探索大鼠骨髓内皮祖细胞的分离培养及鉴定方法。方法：使用密度梯度离心法及差速贴壁法联合的方法培养内皮祖细胞,在倒置显微镜下观察细胞生长情况及形态变化,使用Dil标记的乙酰化低密度脂蛋白和FITC标记的荆豆凝集素1双荧光染色、流式细胞仪检测细胞表面抗原CD34、CD133表达情况。结果与结论：培养前4d细胞增殖不明显,第5～10天迅速增殖,并可见细胞集落及线状结构形成。培养第7天的内皮祖细胞具有吞噬Dil标记的乙酰化低密度脂蛋白和FITC标记的荆豆凝集素1的功能。流式细胞仪检测体外培养第10天的细胞,CD133＋细胞占19.2%,CD34＋细胞占28.7%,CD34＋/CD133＋细胞占19.1%。说明密度梯度离心法联合差速贴壁法可在体外有效分离培养大鼠骨髓内皮祖细胞。     

大鼠骨髓源性内皮祖细胞的分离培养与鉴定

背景：内皮祖细胞因其分离与培养的方法各不相同,在实验中难以重复。目的：探讨大量获取骨髓源性内皮祖细胞分离与培养的方法。方法：通过密度梯度离心法从4周龄SD大鼠骨髓中分离单个核细胞,使用EGM-2MV培养基进行诱导培养,采用形态学特征观察、摄取Dil-Ac-LDL与结合FITC—UEA-1实验、免疫荧光化学鉴定其表面抗原CD133与VEGFR2等方法对其进行鉴定,并通过管腔形成实验观察形成管腔的能力。结果与结论：①形态学观察：分离的骨髓单个核细胞经诱导培养后,在生长的早期（8d左右）、晚期（15d左右）其细胞形态有一定差异,早期以纺锤形、三角形、圆形细胞多见,晚期以圆形、短梭形细胞多见。②摄取Dil-Ac-LDL与结合FITC-UEA-1实验：显示8,21d的细胞均为阳性。⑧免疫荧光化学染色：8d的细胞表达CD133、VEGFR2。④管腔形成实验：在Matrigel基质上15h左右能够生成血管样结构。结果表明：利用密度梯度离心法分离大鼠骨髓单个核细胞后以EGM-2MV进行诱导培养,经过鉴定证明获得的细胞符合内皮祖细胞的特征。这种方法能够简单、快速、可靠、大量地获取内皮祖细胞。     

Thrombin and PAR-1 stimulate differentiation of bone marrow-derived endothelial progenitor cells

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.