人脂肪间充质干细胞对异种小鼠间皮肤移植的免疫调节作用

背景:皮肤移植是治疗大面积烧烫伤最有效的方法之一,如何有效抑制异体皮肤移植后的免疫排斥反应,是目前亟待解决的问题.目的:探讨人脂肪间充质干细胞对异种小鼠间皮肤移植免疫调节作用的影响.方法:取抽脂减肥术后人脂肪组织分离出人脂肪间充质干细胞并培养至第3代,将60只2-4 d龄ICR小鼠随机分为4组,取其皮肤移植至C57BL...     

myocardin基因沉默在PDGF-BB诱导小鼠骨髓间充质干细胞向平滑肌样细胞分化中的作用

目的 构建myocardin特异性siRNA真核表达载体,体外观察其对myocardin基因的沉默效应及对小鼠骨髓间充质干细胞(MSC)向平滑肌样细胞分化过程中的影响.方法 培养小鼠骨髓问充质干细胞并利用血小板源生长因子(PDGF-BB,50 mg/L)联合高浓度胎牛血清(20%FBS)诱导其向平滑肌样细胞分化;构建含U6启动子和myocardin特异短发卡RNA(shRNA)编码序列的质粒载体pGen-myo-shRNA,以含非特异性shRNA编码序列的质粒载体pGenesil-Con(pCon)为阴性对照,分别转染诱导培养后第6天的小鼠MSC,48 h后用RT-PCR技术检测细胞内myocardin在mRNA水平的表达;同时用免疫组织化学方法 检测平滑肌肌球蛋白重链(sM myosin heavy chain,SM-MHC)的表达来鉴定平滑肌样细胞的分化.结果 成功构建myocardin特异性siRNA真核表达载体,利用其沉默myocardin基因后,干扰组相比空白对照组myocardin mRNA表达下调42.86%,差异有统计学意义(P相似文献   

Widespread distribution and muscle differentiation of human fetal mesenchymal stem cells after intrauterine transplantation in dystrophic mdx mouse

Duchenne muscular dystrophy (DMD) is a common X-linked disease resulting from the absence of dystrophin in muscle. Affected boys suffer from incurable progressive muscle weakness, leading to premature death. Stem cell transplantation may be curative, but is hampered by the need for systemic delivery and immune rejection. To address these barriers to stem cell therapy in DMD, we investigated a fetal-to-fetal transplantation strategy. We investigated intramuscular, intravascular, and intraperitoneal delivery of human fetal mesenchymal stem cells (hfMSCs) into embryonic day (E) 14-16 MF1 mice to determine the most appropriate route for systemic delivery. Intramuscular injections resulted in local engraftment, whereas both intraperitoneal and intravascular delivery led to systemic spread. However, intravascular delivery led to unexpected demise of transplanted mice. Transplantation of hfMSCs into E14-16 mdx mice resulted in widespread long-term engraftment (19 weeks) in multiple organs, with a predilection for muscle compared with nonmuscle tissues (0.71% vs. 0.15%, p < .01), and evidence of myogenic differentiation of hfMSCs in skeletal and myocardial muscle. This is the first report of intrauterine transplantation of ontologically relevant hfMSCs into fully immunocompetent dystrophic fetal mice, with systemic spread across endothelial barriers leading to widespread long-term engraftment in multiple organ compartments. Although the low-level of chimerism achieved is not curative for DMD, this approach may be useful in other severe mesenchymal or enzyme deficiency syndromes, where low-level protein expression may ameliorate disease pathology.     

Heparan sulfate enhances the self-renewal and therapeutic potential of mesenchymal stem cells from human adult bone marrow

Insufficient cell number hampers therapies utilizing adult human mesenchymal stem cells (hMSCs) and current ex vivo expansion strategies lead to a loss of multipotentiality. Here we show that supplementation with an embryonic form of heparan sulfate (HS-2) can both increase the initial recovery of hMSCs from bone marrow aspirates and increase their ex vivo expansion by up to 13-fold. HS-2 acts to amplify a subpopulation of hMSCs harboring longer telomeres and increased expression of the MSC surface marker stromal precursor antigen-1. Gene expression profiling revealed that hMSCs cultured in HS-2 possess a distinct signature that reflects their enhanced multipotentiality and improved bone-forming ability when transplanted into critical-sized bone defects. Thus, HS-2 offers a novel means for decreasing the expansion time necessary for obtaining therapeutic numbers of multipotent hMSCs without the addition of exogenous growth factors that compromise stem cell fate.     

Engraftment potential of human placenta-derived mesenchymal stem cells after in utero transplantation in rats

BACKGROUND: Human placental mesenchymal stem cells (hPMCs) are thought tobe multipotent, but their fate after in utero transplantationis not known. METHODS: hPMCs isolated from term placenta were assessed for their phenotypemarkers, mutilineage capacity, and immunomodulatory properties.Their engraftment potential was analyzed in a pregnant rat modelafter in utero transplantation at embryonic day 17. Immunohistochemistry,tracing of labeled cells, fluorescence in situ hybridizationand real-time PCR were used to assess post-transplant chimerism. RESULTS: In vitro, lineage-negative, CD34-negative hPMCs differentiatedinto osteocytes, adipocytes, hepatocytes and endothelial cellswith tube formation, and actively suppressed the rat lymphocyteproliferative response to allogeneic lymphocyte stimulation(P < 0.0001). After in utero transplantation into pregnantrats, a low level of engraftment was achieved in various fetaltissues. Engraftment occurred in more than 60% of the fetalrats. Cells persisted for at least 12 weeks after delivery andevidence was obtained to suggest differentiation into specificlineages, including hepatocytes and hematopoietic cells. However,a greater number of hPMCs migrated to the placenta than to thefetus, thus limiting the degree of cell engraftment in fetalorgans. CONCLUSIONS: We conclude that hPMCs are mutipotent cells that can be engraftedlong-term in immunocompetent rats after in utero transplantation.     

MicroRNA-378*通过抑制CTGF促进人骨髓间充质干细胞凋亡

 目的:研究年龄相关microRNA-378* (miR-378*) 对人骨髓间充质干细胞（hMSCs）存活和凋亡的调控作用。方法:通过microRNA芯片和qRT-PCR检测供体年龄对hMSCs 中miR-378*表达的影响;通过H2O2诱导hMSCs凋亡;通过转染miR-378*模拟物或抑制物,过表达或抑制miR-378*的表达;用MTT、LDH、caspase-3/7、TUNEL检测等方法研究其对hMSCs存活和凋亡的影响;通过siRNA研究结缔组织生长因子（CTGF）对hMSCs存活和凋亡的影响。结果: 随供体年龄增加,hMSCs 中miR-378*的表达增加。H2O2刺激可促进miR-378*表达,抑制CTGF表达。过表达miR-378*可减少hMSCs的存活,促进细胞凋亡。相反,抑制miR-378*的表达促进hMSCs的存活,减少细胞凋亡。同时抑制miR-378*和CTGF的表达,使miR-378*失去对hMSCs存活和凋亡的调控作用。直接抑制CTGF的表达可减少hMSCs的存活,促进细胞凋亡。结论: miR-378*通过抑制CTGF的表达减少hMSCs存活,促进hMSCs凋亡。     

骨髓间充质干细胞移植后在mdx鼠体内的分布研究

目的： 研究骨髓间质干细胞移植治疗Duchenne型肌营养不良鼠(mdx鼠)后体内各主要器官的分布状况。方法: 取第5代SD大鼠骨髓间质干细胞，应用［3H］－TdR标记后以2×107cells／只细胞尾静脉移植到经7Gy γ射线预处理后的7-9周龄mdx鼠体内，分别于移植后24 h、48 h、4周、8周和16周测定血液、肺、肝、骨髓、骨骼肌及心肌的放射性分布计数。结果: 经7Gy γ射线放疗预处理的mdx鼠，在尾静脉移植骨髓干细胞后，24 h肺的放射性分布计数最高，为36.70±3.04；48 h肝的放射性分布计数最高，为36.74±3.28；骨髓分布计数随移植时间延长增多，2周时达到高峰，计数为38.43±4.99，以后逐渐下降，但4月时仍明显高于其它组织器官，计数为13.45±1.37；骨骼肌、心肌的放射性分布计数随移植时间延长明显增高，16周时分别达到4.79±0.94和9.55±1.53。结论: 在MSCs移植后早期，MSCs主要分布于肺、肝等血流丰富的器官，随移植时间延长逐渐归巢到骨髓定居，2周时达到高峰，此后逐渐向损伤器官如骨骼肌、心肌等定向迁移，并且随时间延长分布增加，从而为MSCs定居于肌组织并且分化为肌细胞提供了证据。     

Myocardin重组蛋白表达及其在人骨髓间充质干细胞重编程为血管平滑肌细胞中的作用

目的:研究心肌素(myocardin)重组蛋白的表达及分离纯化方法,并探讨myocardin重组蛋白对人骨髓间充质干细胞(human bone marrow mesenchymal stem cells,h BMSCs)向血管平滑肌细胞转分化的作用。方法:构建myocardin原核表达载体,摸索最佳诱导myocardin重组蛋白表达的方法及优化分离纯化方式。使用纳米转导试剂包裹myocardin形成纳米-蛋白复合体,转染h BMSCs,观察蛋白转导效率;蛋白转导成功后,检测血管平滑肌的特异性标志物平滑肌肌球蛋白重链的表达情况,观察h BMSCs向平滑肌细胞转化情况。结果:与传统方法相比较,高浓度法诱导myocardin重组蛋白的表达量更高,新采用的洗脱方式能获取更多的myocardin重组蛋白;纳米-myocardin复合体可成功转染h BMSCs并诱导其向血管平滑肌样细胞转化。结论:Myocardin重组蛋白能被高效转导到细胞内,并促使h BMSCs重编程为血管平滑肌样细胞。     

IFATS collection: in vivo therapeutic potential of human adipose tissue mesenchymal stem cells after transplantation into mice with liver injury

Mesenchymal stem cells (MSCs), largely present in the adult human body, represent an attractive tool for the establishment of a stem cell-based therapy for liver diseases. Recently, the therapeutic potential and immunomodulatory activity of MSCs have been revealed. Adipose tissue-derived mesenchymal stem cells (AT-MSCs), so-called adipose-derived stem cells or adipose stromal cells, because of their high accessibility with minimal invasiveness, are especially attractive in the context of future clinical applications. The goal of the present study was to evaluate the therapeutic potential of AT-MSCs by their transplantation into nude mice with CCl(4)-caused liver injury. We observed that after transplantation, AT-MSCs can improve liver functions, which we verified by changes in the levels of biochemical parameters. Ammonia, uric acid, glutamic-pyruvic transaminase, and glutamic-oxaloacetic transaminase concentrations returned to a nearly normal level after AT-MSC transplantation. These results raised the question of how AT-MSCs can achieve this. To discover the possible mechanisms involved in this therapeutic ability of AT-MSCs, in vitro production of cytokines and growth factors was analyzed and compared with MSCs from bone marrow (BM-MSCs) and normal human dermal fibroblasts (NHDFs). As a result we observed that AT-MSCs secrete interleukin 1 receptor alpha (IL-1Ralpha), IL-6, IL-8, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemotactic protein 1, nerve growth factor, and hepatocyte growth factor in a volume higher than both BM-MSCs and NHDFs. Thus, our findings suggest that AT-MSCs may account for their broad therapeutic efficacy in animal models of liver diseases and in the clinical settings for liver disease treatment. Disclosure of potential conflicts of interest is found at the end of this article.     

myocardin在骨髓间充质干细胞向平滑肌细胞分化过程中的表达

目的 探讨通过条件培养液(CM)和高浓度血清即20%的胎牛血清(FBS)联合作用下,myocardin在骨髓来源的间充质干细胞向平滑肌细胞(SMC)定向分化过程中的表达特点.方法 采用伞骨髓贴壁法分离骨髓问充质干细胞,CM联合20%FBS诱导骨髓间充质干细胞,同时设立持续10%FBS、单20%FBS及单CM诱导下的骨髓间充质十细胞对照组和SMC阳性对照组,分别于诱导前及诱导3、7、10和14 d时观察细胞形态的变化,并在相应的时间点用免疫荧光法、逆转录聚合酶链反应法、Western blot半定量分析法榆测myocardin以及SMC表面各种标志基因的表达变化,用透射电镜检测诱导后细胞内肌丝存在以此来证实诱导分化成功.结果 光镜观察显示诱导前至诱导3、7、10和14 d时,骨髓问允质十细胞南纺锤形、多角形、扁平形和小圆形等多种形态逐渐转变为单一的长梭形,在诱导21 d后显示出明显的峰-谷特征.免疫荧光结果显示表达myocardin的阳性细胞数量逐渐增多,表达部位由胞质逐渐移向胞核,而表达平滑肌标志基因Ot一平滑肌肌动蛋白(Ot.SMA)、平滑肌肌动蛋白重链(SM-MHC)的细胞也随之增加,同时联合诱导后3、7、lO和14 d表达myocardin和平滑肌标志基因(α-SMA或SM-MHC)的双阳性细胞数最逐渐增加.RT-PCR结果显示myocardin的mRNA表达逐渐上调,在诱导7 d达到高峰后表达基本稳定(P<0.05);平滑肌标志基因α-SMA及SM22α的表达随着myocardin表达上调而增加(r=O.81,P<0.05),诱导10 d后表达基本稳定.Western blot结果显示myocardin蛋白和平滑肌标志基因α-SMA蛋白表达量在诱导后明显增加(r=0.84,P<0.05).透射电镜结果显示诱导21 d后的分化细胞中有肌丝的存在.在不同时间点各组之间的差异有统计学意义(P<0.05).结论 CM联合高浓度的血清可有效诱导骨髓间充质干细胞向SMC分化,myocardin在此分化过程中起了重要作用.骨髓来源的间充质干细胞可以在诱导下定向分化成为SMC.     

人脐带来源间充质干细胞移植急性阿尔茨海默病模型小鼠引发的免疫应答反应*

背景：阿尔茨海默病患者的外周血和脑脊液中相应细胞因子浓度较正常人相比有明显的改变,加强了阿尔茨海默病伴随着免疫应答的结论,提示炎性应答可能参与了阿尔茨海默病神经改变的级联反应。 目的：探讨人脐带间充质干细胞在急性阿尔茨海默病小鼠模型中引发的免疫应答反应与外周血中各细胞因子水平的关系。 方法：取第5代人脐带间充质干细胞,调整细胞浓度为1×109 L-1待用。C57小鼠随机分为4组,间充质干细胞组侧脑室注射β-淀粉样蛋白1~42,尾静脉注射1 mL人脐带间充质干细胞;模型组侧脑室注射β-淀粉样蛋白1~42,尾静脉注射等体积生理盐水;生理盐水组不造模,尾静脉给予等体积的生理盐水;正常组不造模,不给予任何干预措施。 结果与结论：与正常组相比,模型组小鼠在Morris水迷宫实验中逃避潜伏期延长、第一次穿环时间增加而穿环次数减少,间充质干细胞组小鼠逃避潜伏期有所减少,第一次穿环时间减少,穿环次数有所提高,但改善情况较模型组比较不明显。与正常组小鼠相比,模型组在造模后4 d出现N-乙酰天冬氨酸降低,肌醇升高,造模后7 d外周血炎性因子白细胞介素1β、肿瘤坏死因子α水平升高,白细胞介素10水平升高不明显;与模型组相比,注射脐带间充质干细胞7 d后外周血各炎性因子水平有所降低。结果表明人脐带间充质干细胞治疗阿尔茨海默病可能是通过调节免疫应答的途径来实现的。关键词：阿尔茨海默病;小鼠;β-淀粉样蛋白;人脐带;间充质干细胞 doi:10.3969/j.issn.1673-8225.2012.19.012     

骨髓间充质干细胞移植治疗mdx鼠：3个月疗效

背景：干细胞移植治疗肌营养不良症是目前的研究热点,相对造血干细胞移植,间充质干细胞移植风险较小。 目的：观察骨髓间充质干细胞移植治疗Duchenne型肌营养不良鼠(mdx鼠)的疗效。 方法：4周龄mdx鼠16只,随机分为治疗组与对照组,每组8只,经静脉移植及肌肉局部注射C57BL/6小鼠的骨髓间充质干细胞或等量生理盐水。 结果与结论：移植3个月后,治疗组较对照组血清肌酸激酶水平下降,骨骼肌肌膜部分有dystrophin蛋白表达,而对照组检测不到dystrophin蛋白表达。但是两组的运动功能无明显改善。结果初步表明骨髓间充质干细胞移植对mdx鼠有一定的治疗作用,可能使肌细胞膜破坏减少,延缓病情发展。     

Ultrasound-mediated microbubble destruction enhances the therapeutic effect of intracoronary transplantation of bone marrow stem cells on myocardial infarction

Objective: The combination of intracoronary transplantation and ultrasound-mediated microbubble destruction may promote effective and accurate delivery of bone marrow stem cells (BMSCs) into the infarct zone. To test this hypothesis in this study we examined the effectiveness of ultrasound-mediated microbubble destruction in combination with intracoronary transplantation of BMSCs for the treatment of myocardial infarction in canine model of acute myocardial infarction. Method: The dogs were randomly assigned to four groups: PBS, ultrasound-mediated microbubble destruction, BMSCs, BMSCs together with ultrasound-mediated microbubble destruction. At 28 days post-surgery, cardiac function and the percentage of perfusion defect area to total left ventricular perfusion area (DA%) were determined by myocardial contrast echocardiography. Nitro blue tetrazolium staining was performed to determine myocardial infarct size, hematoxylin and eosin staining for assessing microvascular injury, Masson’s staining for analyzing myocardial tissue collagen, immunohistochemical analysis of α-actin to measure cardiac contractile function and of BrdU-labeled myocardial cells to measure the number of the BMSCs homing to the infarcted region. Results: The transplantation of BMSCs significantly improved heart function and DA% (P < 0.05). The group that received ultrasound-mediated microbubble destruction with BMSCs transplantation showed the most improvement in heart function and DA% (P < 0.05). This group also showed a denser deposition of BMSCs in the coronary artery and more BrdU positive cells in the infarcted region, had the maximum number of α-actin positive cells, showed the smallest myocardial infarct area compared to other groups (P< 0.05). Conclusion: Ultrasound-mediated microbubble destruction increases the homing of BMSCs in the target area following intracoronary transplantation, which allows more BMSCs to differentiate into functional cardiomyocytes, thereby reducing myocardial infarct size and improving cardiac function.     

Nitric oxide releasing hydrogel enhances the therapeutic efficacy of mesenchymal stem cells for myocardial infarction

Stem cell therapy has been proved to be an effective approach to ameliorate the heart remodeling post myocardial infarction (MI). However, poor cell engraftment and survival in ischemic myocardium limits the successful use of cellular therapy for treating MI. Here, we sought to transplant adipose derived-mesenchymal stem cells (AD-MSCs) with a hydrogel (NapFF-NO), naphthalene covalently conjugated a short peptide, FFGGG, and β-galactose caged nitric oxide (NO) donor, which can release NO molecule in response to β-galactosidase. AD-MSCs, either from transgenic mice that constitutively express GFP and firefly luciferase (Fluc), or express Fluc under the control of VEGFR2 promoter, were co-transplanted with NapFF-NO hydrogel into murine MI models. Improved cell survival and enhanced cardiac function were confirmed by bioluminescence imaging (BLI) and echocardiogram respectively. Moreover, increasing VEGFR2-luc expression was also tracked in real-time in vivo, indicating NapFF-NO hydrogel stimulated VEGF secretion of AD-MSCs. To investigate the therapeutic mechanism of NapFF-NO hydrogel, cell migration assay, paracrine action of AD-MSCs, and histology analysis were carried out. Our results revealed that condition medium from AD-MSCs cultured with NapFF-NO hydrogel could promote endothelial cell migration. Additionally, AD-MSCs showed significant improvement secretion of angiogenic factors VEGF and SDF-1α in the presence of NapFF-NO hydrogel. Finally, postmortem analysis confirmed that transplanted AD-MSCs with NapFF-NO hydrogel could ameliorate heart function by promoting angiogenesis and attenuating ventricular remodeling. In conclusion, NapFF-NO hydrogel can obviously improve therapeutic efficacy of AD-MSCs for MI by increasing cell engraftment and angiogenic paracrine action.     

通心络超微粉对猪急性心肌梗死后移植骨髓间充质干细胞的影响

目的探讨通心络超微粉能否改善猪急性心肌梗死(AMI)局部微环境,从而提高移植自体骨髓间充质干细胞(MSCs)在体存活和移植效果。方法28头中华小型猪被分为4组(n=7),分别为对照、通心络超微粉(自AMI前3 d用药直至后4 d)、MSCs移植和通心络超微粉+MSCs联合组。AMI模型由阻断冠状动脉左前降支90 min制成,再灌注后即刻经心肌内注射DAPI标记的自体骨髓MSCs(3×107cells/动物)。在移植后1周(基线)和6周(终点),以核磁共振(MRI)检测心功能。6周后处死动物,检测移植细胞在体存活和分化、梗死周边心肌凋亡和氧化应激指标。结果终点时,与对照组、MSCs组和通心络超微粉组相比,联合组纤维化和炎症细胞浸润显著减轻,并伴较多存活心肌。与MSCs移植组相比,联合组移植细胞的在体存活和成心肌分化能力均显著增强(P<0.0001)。MRI显示在基线时各心功能参数无显著差异(P>0.05);终点时,和对照组相比,仅联合组左室射血分数(LVEF)显著增加(P<0.0001),室壁运动障碍节段数、梗死室壁增厚率、梗死面积和左室质量指数均显著减小(P<0.0001)。终点时,和对照组相比,在通心络超微粉组和联合组梗死周边区的心肌凋亡均显著减轻(P<0.0001),SOD显著增加(P<0.05),MDA显著减少(P<0.05)。结论实验表明AMI再灌注后即刻心肌内移植自体骨髓MSCs生存和分化能力有限,未产生显著功能学获益。而围移植期使用通心络超微粉可显著改善梗死局部微环境,提高移植细胞存活和分化,并产生显著心功能获益。     

脐血间充质干细胞移植与免疫调节

背景：近年研究显示,脐血间充质干细胞的自我更新和多向分化潜能为细胞移植治疗提供了基础条件,而其免疫调节功能也极大地拓展了细胞治疗的方向和范围。 目的：就近期脐血间充质干细胞的免疫调节和细胞移植研究进行回顾分析。 方法：应用计算机以“umbilical cord blood-derived mesenchymal stem cells”为关键词检索Pubmed数据库,以“脐血间充质干细胞”为关键词检索知网数据库,时间限定为2008-01/2011-06,语言种类为“English”和汉语。通过阅读标题和摘要进行初筛,排除研究内容与此文无关的文献、重复性研究及Meta分析,选择近期发表或发表在权威杂志的30篇文献进行综述。 结果与结论：脐血间充质干细胞具有与骨髓间充质干细胞相似的自我更新和多向分化潜能。通过细胞移植技术,脐血间充质干细胞在糖尿病、神经退化性疾病如阿尔茨海默病和帕金森病等以及神经损伤后的修复治疗方面显示出很强的潜力。同时,脐血间充质干细胞又具有免疫调节作用,其可通过下调T细胞的增殖,降低免疫反应。利用该特点,脐血间充质干细胞在一些免疫性疾病,如移植物抗宿主病和狼疮性肾炎等疾病的细胞治疗方面也取得了积极的进展。     

骨髓间充质干细胞移植后的肝功能重建

背景：细胞移植是治疗肝功能衰竭的一种有效方法,而理想的细胞源和最佳的移植途径一直是各实验室不断研究的目标。 目的：观察骨髓间充质干细胞移植对急性肝衰竭大鼠肝功能重建的影响和最佳移植途径。 方法：以D-氨基半乳糖胺作为肝脏毒剂,构建雌性SD大鼠急性肝衰竭模型。以雄性SD大鼠骨髓间充质干细胞为细胞源,通过腹股沟静脉和脾内移植两种途径植入肝衰竭大鼠,动态检测多项肝功能血生化指标。并以sry基因为分子标志,采用PCR技术检测骨髓间充质干细胞在肝脏内的存活状态。 结果与结论：骨髓间充质干细胞经腹股沟静脉和脾内移植均可降低血清谷丙转氨酶、谷草转氨酶、总胆红素水平,提高白蛋白合成能力,改善肝功能,降低动物死亡率。经腹股沟静脉移植组死亡率低于经脾内移植组。移植后7~30 d在受体大鼠肝脏内均能检测到sry基因阳性细胞的存在,而相应对照组未能检测到sry基因阳性细胞。结果表明①骨髓间充质干细胞移植可改善急性肝衰竭大鼠的肝功能。②骨髓间充质干细胞可在受体肝脏内存活。③经腹股沟静脉移植操作简便易行,死亡率较低,是较好的细胞移植途径。     

人脂肪间充质干细胞的免疫调节作用

背景：脂肪间充质干细胞的免疫调节作用及其机制如何,目前了解甚少。 目的：观察人脂肪间充质干细胞体外对淋巴细胞增殖、细胞亚群和分泌细胞因子水平的影响,以了解其免疫调节作用。 方法：分离培养成人脂肪间充质干细胞,流式细胞仪鉴定细胞表型,分别成骨、成心肌细胞诱导,免疫细胞化学染色对诱导后的细胞进行鉴定。分离培养人外周血淋巴细胞,按不同浓度(1∶1,1∶10,1∶100)与脂肪间充质干细胞共培养,并添加植物血凝素刺激,同时设立对照组,3 d后收集上清。 结果与结论：脂肪间充质干细胞与淋巴细胞共培养后检测3种浓度组淋巴细胞的A值明显低于阳性对照组,其中1∶1浓度组最低(P < 0.05);CD4⁺CD25⁺Tregs亚群比例明显高于阳性对照组,且1∶1浓度组最高;细胞因子白细胞介素2、白细胞介素4、γ-干扰素水平明显减低,但白细胞介素10水平升高,且具有一定的浓度依赖性(P < 0.05)。提示脂肪间充质干细胞在体外能明显抑制淋巴细胞的增殖,这种抑制作用可能与其增加CD4⁺CD25⁺Tregs亚群数量,以及改变淋巴细胞分泌细胞因子的水平有关。     

Paracrine effect of Wnt11-overexpressing mesenchymal stem cells on ischemic injury

Our previous studies have suggested that transduction of Wnt11 directly increases bone marrow-derived mesenchymal stem cells (MSCs) differentiation into cardiac phenotypes. In this study, we investigated whether Wnt11 enhances MSC-mediated cardioprotection via paracrine fashion after acute ischemia. MSCs were harvested from male rat bone marrow and transduced with Wnt11 (MSC(Wnt11)). An acute myocardial infarction model in rats was developed by ligation of the left anterior descending coronary artery. MSC(Wnt11) were transplanted into the peri-infarct region after acute myocardial infarction. To mimic ischemic injury, cultured cardiomyocytes (CMs) isolated from neonatal ventricles were exposed to hypoxia. ELISA studies indicated that the release of Wnt11 (3.45-fold) as well as transforming growth factor-β2 (TGFβ2) (1.5-fold) was significantly increased from MSC(Wnt11) compared with transduced control MSC (MSC(Null)). Hypoxia-induced apoptosis and cell death was significantly reduced when CM were co-cultured with MSC(Wnt11) in a dual chamber system. The cell protection mediated by MSC(Wnt11) was mimicked by treating CM with conditioned medium obtained from MSC(Wnt11) and abrogated by Wnt11- and TGFβ2 neutralizing antibodies. Further, animals receiving MSC(Wnt11) showed a significant improvement in cardiac contractile function as assessed by echocardiography. Masson trichrome and TUNEL staining showed a significant reduction in infarct size and apoptosis of CM in MSC(Wnt11)-treated animals. Transplantation of MSC(Wnt11) improved cardiac function. The release of Wnt11 and other factors from transplanted MSC(Wnt11) is more likely responsible for protection of native CM at risk.     

Neural induction with neurogenin1 increases the therapeutic effects of mesenchymal stem cells in the ischemic brain

Mesenchymal stem cells (MSCs) have been shown to ameliorate a variety of neurological dysfunctions. This effect is believed to be mediated by their paracrine functions, since these cells rarely differentiate into neuronal cells. It is of clinical interest whether neural induction of MSCs is beneficial for the replacement therapy of neurological diseases. Here we report that expression of Neurogenin1 (Ngn1), a proneural gene that directs neuronal differentiation of progenitor cells during development, is sufficient to convert the mesodermal cell fate of MSCs into a neuronal one. Ngn1-expressing MSCs expressed neuron-specific proteins, including NeuroD and voltage-gated Ca2+ and Na+ channels that were absent in parental MSCs. Most importantly, transplantation of Ngn1-expressing MSCs in the animal stroke model dramatically improved motor functions compared with the parental MSCs. MSCs with Ngn1 populated the ischemic brain, where they expressed mature neuronal markers, including microtubule associated protein 2, neurofilament 200, and vesicular glutamate transporter 2, and functionally connected to host neurons. MSCs with and without Ngn1 were indistinguishable in reducing the numbers of Iba1+, ED1+ inflammatory cells, and terminal deoxynucleotidyl transferase dUTP nick-end labeling(+) apoptotic cells and in increasing the numbers of proliferating Ki67+ cells. The data indicate that in addition to the intrinsic paracrine functions of MSCs, motor dysfunctions were remarkably improved by MSCs able to transdifferentiate into neuronal cells. Thus, neural induction of MSCs is advantageous for the treatment of neurological dysfunctions.