骨髓间质干细胞移植与心肌再生

骨髓间质干细胞是多能细胞，在体外培养时，通过诱导可分化为肌肉细胞等。新近进行的骨髓间质干细胞移植实验，为治疗心肌梗死提供了一个潜在的、较为光明的前景。     

骨髓间充质干细胞移植对心肌缺血/再灌注大鼠心肌胶原与血管新生的影响

目的通过心肌缺血/再灌注模型观察大鼠骨髓间充质干细胞心肌移植对心肌细胞外胶原、小血管新生和心功能变化的影响,并探讨其机制。方法分离、原代培养Wistar大鼠骨髓间充质干细胞,建立缺血/再灌注动物模型,分为假手术组、心肌梗死 骨髓间充质干细胞移植组、心肌梗死对照组,观察骨髓间充质干细胞移植后动物模型血流动力学指标、心肌梗死面积和心肌细胞形态、心肌间质、血管密度、心室膨展指数、心肌细胞横截面积和心肌胶原变化。结果(1)骨髓间充质干细胞心肌移植可缩小60min缺血/再灌注大鼠28d心肌梗死面积;(2)骨髓间充质干细胞移植可减轻心肌梗死动物左心室重塑,但心功能改善作用不明显;(3)骨髓间充质干细胞移植发挥细胞外基质抑制、促血管生成作用,心肌间质胶原含量、胶原分数下降,心肌毛细血管、小动脉密度增加。结论骨髓间充质干细胞移植可改善心肌梗死后心室重塑、促进血管新生和降低心肌胶原作用。     

骨髓间质干细胞移植与心肌再生

骨髓间质干细胞是多能细胞，在体外培养时，通过诱导可分化为肌肉细胞等，新近进行的骨髓间质干细胞移植实验，为治疗心肌梗死提供了一个潜在的，较为光明的前景。     

骨髓间质干细胞静脉移植治疗大鼠急性心肌梗死的实验研究

目的:观察多次静脉移植骨髓间质干细胞治疗心肌梗死的可行性及对心肌梗死后心功能的影响。方法:骨髓间质干细胞培养传至5代后,制备成终浓度为4×109个/L的悬液备用。将40只SD大鼠均结扎冠状动脉左前降支,建立急性心肌梗死模型后,随机分为3组:①对照组(10只):只静脉注射0.85%氯化钠溶液;②静脉移植组(15只):心肌梗死模型制备后24h,从尾静脉注射骨髓间质干细胞0.5ml(含2×109个/L)连续7d;③心外膜移植组(15只):心肌梗死模型制备后1~3h,于梗死周边区(心肌颜色苍白区周边)分6点注射骨髓间质干细胞,每点50μl。5周后,观察3组的生存情况及心脏的结构功能。结果:心肌梗死对照组有3只大鼠死亡,其他组无死亡。与对照组相比,静脉移植组、心外膜移植组的左室结构与功能明显改善(P<0·05),静脉移植组与心外膜移植组差异无统计学意义(P>0·05)。结论:骨髓间质干细胞可以在体外大量扩增,异体输入无不良反应,静脉注射与直接心肌注射无明显差别,方法可行。     

间质干细胞移植治疗心肌梗死

心肌细胞在成熟个体中属永久性细胞，发生局部心肌梗死后，不能再生而影响心功能。间质干细胞移植于心肌梗死部位，在局部诱导分化为心肌细胞、血管内皮细胞，以修复坏死的心肌，重建梗死部位的血运，而且可以将治疗性基因转染骨髓间质干细胞后进行移植，以最大限度恢复心功能。     

骨髓间质干细胞治疗心肌梗死研究进展

以往认为,心肌细胞不能再生,心肌受损后只能形成瘢痕组织来修复。近年研究显示,在急性心肌梗死（AMI）患者的心脏中,特别在梗死周边区域,也有少量心肌细胞发生有丝分裂。虽然这些细胞的分裂能力有限,但心肌细胞具有分裂能力的新观念将干细胞与心肌细胞移植治疗联系起来,使干细胞移植治疗心肌梗死成为可能。现将骨髓间质干细胞移植重建受损心肌的研究进展综述如下。     

干细胞移植治疗心肌梗死

近几年干细胞移植在心肌梗死方面的应用研究有了较大突破 ,作者对干细胞的基本概念、调控、分离纯化、定向诱导以及胚胎干细胞移植、骨髓干细胞移植、骨骼肌干细胞移植和其它成体干细胞移植治疗心肌梗死研究的最新进展进行综述。     

骨髓干细胞移植治疗心肌梗死的新观点及进展

骨髓干细胞移植治疗心肌梗死是近几年研究的热点,国内外的研究者们作了大量工作,对其作用机制有了进一步的了解,而骨髓干细胞与其他治疗方法的结合进一步发挥了干细胞治疗的潜能,在临床中干细胞的治疗也逐渐增多.本文就此对骨髓干细胞移植治疗心肌梗死的最新成果、进展着重阐述.     

心肌梗死治疗的新方向--干细胞移植

近年来干细胞移植已逐渐应用于治疗心肌梗死,有望将来在临床得到推广。目前可供移植的细胞包括骨髓间质干细胞、内皮祖细胞、成骨骼肌细胞,可通过直接心肌注射、经冠脉内和经静脉内注射三种途径移植,相关的临床研究提示能明显改善患者心功能,提高生活质量,但是许多问题现在尚未得到解决,有待进一步研究。     

骨髓干细胞动员治疗急性心肌梗死研究进展

研究发现骨髓干细胞可以分化为心肌细胞、血管内皮细胞以及平滑肌细胞 ,从而为骨髓干细胞治疗心肌梗死提供了基本的理论依据。此外 ,一些研究表明心肌梗死早期伴随有自发性骨髓干细胞的梗死区定向迁移 ,而由于目前已知的多种骨髓干细胞移植方案具有一定的复杂性和潜在危险性 ,动员骨髓干细胞治疗急性心肌梗死成为目前研究的前沿问题。     

骨髓基质干细胞自体移植治疗心肌梗死的研究进展

骨髓基质干细胞(MSC)具有良好的分化潜能,能分化为心肌细胞和血管内皮细胞,从而再生心肌和血管,重塑心肌结构,改善心肌收缩功能和室壁顺应性,促进血管再生,建立有效冠脉侧枝循环,提高心脏整体功能,既改善了血供又解决心肌细胞数量减少这一心力衰竭的根本原因;而自体移植不受来源限制,取材方便、创伤小,更新率低而代谢活力高,由其分化来的心肌细胞能与周围受体肌肉细胞进行有效的电机械偶合,容易通过转基因技术获得目标基因并在体内外长期表达,也不存在免疫排斥和基因突变等安全性问题,因此作为心肌梗死(MI)疾病治疗的新途径有着广阔的前景.现就近年来国内外MSC自体移植在治疗MI方面的研究进展作一综述.     

Mesenchymal Stem Cells Pretreatment With Stromal-Derived Factor-1 Alpha Augments Cardiac Function and Angiogenesis in Infarcted Myocardium

BackgroundStem cell therapy is among the novel approaches for the treatment of post-myocardial infarction cardiomyopathy. This study aims to compare the effect of stromal-derived factor 1 α (SDF1α), mesenchymal stem cells (MSCs) in combination with the lentiviral production of vascular endothelial growth factor (VEGF) on infarct area, vascularization and eventually cardiac function in a rat model of myocardial infarction (MI).MethodsThe influence of SDf1α on MSCs survival was investigated. MSCs were transduced via a lentiviral vector containing VEGF. After that, the effect of mesenchymal stem cell transfection of VEGF-A165 and SDf1α preconditioning on cardiac function and scar size was investigated in five groups of MI rat models. The MSC survival, cardiac function, scar size, angiogenesis, and lymphocyte count were assessed 72 hours and 6 weeks after cell transplantation.ResultsSDF1α decreased the lactate dehydrogenase release in MSCs significantly. Also, the number of viable cells in the SDF1α-pretreated group was meaningfully more than the control. The left ventricular systolic function significantly enhanced in groups with ^p240MSC, ^SDF1αMSC, and ^VEGF-A165MSC in comparison to the control group.ConclusionsThese findings suggest that SDF1α pretreatment and overexpressing VEGF in MSCs could augment the MSCs' survival in the infarcted myocardium, reduce the scar size, and improve the cardiac systolic function.     

Mesenchymal stem cell injection ameliorates the inducibility of ventricular arrhythmias after myocardial infarction in rats

Background

Mesenchymal stem cell transplantation is a promising new therapy to improve cardiac function after myocardial infarction (MI). The electrophysiological consequences of MSC implantation has not been systematically studied.

Methods

We investigated the electrophysiological and arrhythmogenic effects of mesenchymal stem cells (MSCs) therapy in experimental infarction model. Rats were subjected to MI operation by LAD ligation and randomly allocated to receive intramyocardially injection PBS (MI-PBS) or 5 × 10⁵ EGFP labeled MSCs (MI-MSCs). Electrophysiological study, histological examination, and western blotting were performed 2 weeks after cell transplantation.

Results

Programmed electrical stimulation (PES) showed a significant reduced inducible ventricular tachycardias (VTs), raised ventricular fibrillation threshold (VFT) and prolonged ventricular effective refractory period (VERP) in MSC-treated rats compared to PBS-treated animals. MSC implantation led to markedly longer action potential duration (APD) and shorter activation time (AT) in infarcted border zone (IBZ) of left ventricular epicardium compared with PBS-treated hearts. Histological study revealed that fibrotic area and collagen deposition in infarcted region were significantly lower in MI-MSC group than in MI-PBS group. Abnormal alterations of Connexin 43 including reduction and lateralization were significantly attenuated by MSC treatment.

Conclusions

This study provide strong evidence that MSC implantation ameliorates interstitial fibrosis and the remodeling of gap junction, attenuates focal heterogeneity of reporlarization and conduction and reduces vulnerability to VTs. The results suggest that MSC transplantation might emerge as a new preventive strategy against VAs besides improving cardiac performance in ischemic heart disease.     

Mesenchymal stem cells: biology, pathophysiology, translational findings, and therapeutic implications for cardiac disease

Mesenchymal stem cells (MSCs) are a prototypical adult stem cell with capacity for self-renewal and differentiation with a broad tissue distribution. Initially described in bone marrow, MSCs have the capacity to differentiate into mesoderm- and nonmesoderm-derived tissues. The endogenous role for MSCs is maintenance of stem cell niches (classically the hematopoietic), and as such, MSCs participate in organ homeostasis, wound healing, and successful aging. From a therapeutic perspective, and facilitated by the ease of preparation and immunologic privilege, MSCs are emerging as an extremely promising therapeutic agent for tissue regeneration. Studies in animal models of myocardial infarction have demonstrated the ability of transplanted MSCs to engraft and differentiate into cardiomyocytes and vasculature cells, recruit endogenous cardiac stem cells, and secrete a wide array of paracrine factors. Together, these properties can be harnessed to both prevent and reverse remodeling in the ischemically injured ventricle. In proof-of-concept and phase I clinical trials, MSC therapy improved left ventricular function, induced reverse remodeling, and decreased scar size. This article reviews the current understanding of MSC biology, mechanism of action in cardiac repair, translational findings, and early clinical trial data of MSC therapy for cardiac disease.     

Improved graft mesenchymal stem cell survival in ischemic heart with a hypoxia-regulated heme oxygenase-1 vector.

OBJECTIVES: The goal of this study was to modify mesenchymal stem cells (MSCs) cells with a hypoxia-regulated heme oxygenase-1 (HO-1) plasmid to enhance the survival of MSCs in acute myocardial infarction (MI) heart. BACKGROUND: Although stem cells are being tested clinically for cardiac repair, graft cells die in the ischemic heart because of the effects of hypoxia/reoxygenation, inflammatory cytokines, and proapoptotic factors. Heme oxygenase-1 is a key component in inhibiting most of these factors. METHODS: Mesenchymal stem cells from bone marrow were transfected with either HO-1 or LacZ plasmids. Cell apoptosis was assayed in vitro after hypoxia-reoxygen treatment. In vivo, 1 x 10(6) of male MSC(HO-1), MSC(LacZ), MSCs, or medium was injected into mouse hearts 1 h after MI (n = 16/group). Cell survival was assessed in a gender-mismatched transplantation model. Apoptosis, left ventricular remodeling, and cardiac function were tested in a gender-matched model. RESULTS: In the ischemic myocardium, the MSC(HO-1) group had greater expression of HO-1 and a 2-fold reduction in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling-positive cells compared with the MSC(LacZ) group. At seven days after implantation, the survival MSC(HO-1) was five-fold greater than the MSC(LacZ) group; MSC(HO-1) also attenuated left ventricular remodeling and enhanced the functional recovery of infarcted hearts two weeks after MI. CONCLUSIONS: A hypoxia-regulated HO-1 vector modification of MSCs enhances the tolerance of engrafted MSCs to hypoxia-reoxygen injury in vitro and improves their viability in ischemic hearts. This demonstration is the first showing that a physiologically inducible vector expressing of HO-1 genes improves the survival of stem cells in myocardial ischemia.     

骨髓间充质干细胞同种移植治疗急性心肌梗死的实验研究

目的探讨骨髓间充质干细胞(MSCs)同种移植治疗急性心肌梗死的可行性。方法50只Wistar大鼠随机分为两组,对照组和移植组各25只。应用液氮冷冻法制作心肌梗死模型。移植组梗死部位注入经5-氮胞苷(5-aza)诱导和溴氮胞苷标记的大鼠MSCs,对照组梗死部位注入等容量DMEM液。分别于术前1天、术后1周和术后4周行超声心动图检查,以收缩期峰值速度(Vs)、左室舒张末容积(LVEDV)和左室射血分数(LVEF)为指标评价心功能。移植组于术后4周处死,移植心肌行溴氮胞苷免疫组化染色。结果对照组(n=13)和移植组(n=15)相比,术前及术后1周的心功能差异均无统计学意义(P>0.05),术后4周差异有统计学意义(P<0.05),术后4周移植组心功能明显优于对照组。移植部位免疫组化可见溴氮胞苷染色阳性细胞。结论经5-aza诱导的MSCs同种移植入大鼠急性心肌梗死模型的受损心肌后能存活并改善宿主的心功能。     

Direct intramyocardial injection of mesenchymal stem cell sheet fragments improves cardiac functions after infarction

AIMS: Cell transplantation is a promising approach for patients with myocardial infarction. However, following injection, retention of the transplanted cells in the injected area remains a central issue, which can be deleterious to cell transplantation therapy. We hypothesized that the use of cell sheet fragments, with the preservation of extracellular matrix (ECM), may significantly increase cell retention and thus improve cell therapy. METHODS AND RESULTS: Mesenchymal stem cell (MSC) sheet fragments with ECM were fabricated. Experimental myocardial infarction was created in male syngeneic Lewis rats. Thirty minutes after myocardial infarction, an intramyocardial injection was conducted with a needle directly into the peri-infarct areas. There were four treatment groups (n > or = 10): sham; phosphate buffered saline; dissociated MSCs; and MSC sheet fragments. Echocardiography and pressure measurements were assessed postoperatively. At retrieval, the hearts were fixed for histological evaluation. After injection, the MSC sheet fragments remained intact, while the complete cell sheets were torn into pieces. The results obtained in the echocardiography and pressure measurements revealed a superior heart function in the MSC sheet fragment group compared with the dissociated MSC group (P < 0.05). The MSC sheet fragments were able to conform and align their inherent ECM along the interstices of the muscular tissues at the injection sites, while only a few cells were identified in the dissociated MSC group at 12 weeks postoperatively. Additionally, transplantation of the MSC sheet fragments stimulated a significant increase in vascular density (P < 0.05) and enhanced the graft/host cell connection. CONCLUSION: The MSC sheet fragments may serve as a cell delivery vehicle by providing a favourable ECM environment to retain the transplanted cells and improve the efficacy of therapeutic cell transplantation.     

Cellular cardiomyoplasty in large myocardial infarction: Can the beneficial effect be enhanced by ACE‐inhibitor therapy?

BACKGROUND: Cellular cardiomyoplasty with bone marrow derived stromal (MSC) and mononuclear (BMNC) cells has been shown to improve performance of infarcted hearts. We performed a comparative study with MSC and BMNC and tested the hypothesis that captopril treatment could enhance the beneficial effect of cell therapy in large myocardial infarctions. METHODS: Male syngeneic Wistar rats underwent experimental infarction and were randomized to receive 1-3 x 10(6) MSC, 10(8) BMNC or vehicle (BSS group). Two additional groups were treated with captopril and received 1-3 x 10(6) MSC (Cap.MSC) or vehicle (Cap). RESULTS: The ejection fraction (EF%) of MSC and BMNC-treated rats was higher than in the BSS rats, eight weeks after transplantation (33.0+/-4.0, 34.0+/-2.0 and 20.0+/-2.0% respectively, P<0.01). Both captopril-treated groups improved EF% similarly. But only captopril plus MSC treatment almost restored cardiac function to control levels, 8 weeks after injection (60.50+/-5.40% vs. 41.00+/-4.50% in Cap.MSC and Cap respectively, P<0.05). Many DAPI-labelled cells were found in the scar tissue of the left ventricle only in the Cap.MSC group. CONCLUSIONS: Cell transplantation with both MSC and BMNC produced a similar stabilisation of heart function, but the success of the cell engraftment and the recovery of cardiac performance were dependent on concomitant treatment with captopril.     

骨髓间充质干细胞向心肌分化的实验研究

目的:研究骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)分化为心肌样细胞的能力,用于心肌补片治疗心肌梗死的研究。方法:分离C57/BSL小鼠BMSCs,全培养差速贴壁法,经过贴壁培养至第3代,流式细胞仪鉴定细胞表面标志(CD34、CD45、CD73、CD90),经10μmol/L的5-氮杂胞苷诱导细胞,24 h后更换完全培养基培养,2 w后进行免疫荧光染色,荧光显微镜观察心肌钙蛋白T(cTnT)和连接素蛋白43(CX43)的表达。结果:流式鉴定结果显示CD34、CD45阴性,CD73强阳性,CD90弱阳性。免疫荧光染色显示,诱导后细胞高表达心肌细胞特异性蛋白cTnT,连接素蛋白CX43表达水平明显增加。结论:5-aza可以诱导BMSCs大量表达心肌特异性蛋白cTnT和细胞连接素蛋白(CX43),干细胞分化为心肌样细胞,为干细胞移植治疗小鼠心梗提供种子细胞。