腺病毒介导的肝细胞生长因子/血管内皮生长因子双基因转染骨髓间充质干细胞移植治疗心肌梗死***

背景：骨髓间充质干细胞可以分化为心肌细胞,促进血管再生,但在移植早期其自身分泌的细胞因子不足以维持良好的分化和再生。 目的：验证腺病毒介导的肝细胞生长因子和血管内皮生长因子双基因转染新西兰兔骨髓间充质干细胞移植对新西兰兔梗死心肌组织的修复重建和血管再生的影响。 方法：腺病毒介导肝细胞生长因子/血管内皮生长因子双基因转染BrdU标记的新西兰兔骨髓间充质干细胞。取新西兰兔50只建立急性心肌梗死模型,4周后随机分为5组,分别于梗死心肌内注射：①骨髓间充质干细胞/Ad.血管内皮生长因子+肝细胞生长因子。②骨髓间充质干细胞/Ad. 肝细胞生长因子。③骨髓间充质干细胞/Ad.血管内皮生长因子。④骨髓间充质干细胞。⑤对照组注射等量无血清IMDM培养液。移植4周后观察移植细胞的分化和新生血管的形成,并通过超声多普勒检测心功能变化。 结果与结论：除对照组外,其余4组兔心功能都较移植前有明显改善(P < 0.05),其中移植双基因转染骨髓间充质干细胞/Ad.血管内皮生长因子+肝细胞生长因子组兔的心功能改善程度要明显高于其他3组。部分BrdU染色阳性的细胞可以分化成为内皮细胞,参与构成了梗死区域的新生毛细血管。与对照组比较,其余4组都有明显的血管新生(P < 0.05),而以骨髓间充质干细胞/Ad.血管内皮生长因子+肝细胞生长因子组最显著。提示肝细胞生长因子/血管内皮生长因子双基因转染新西兰兔骨髓间充质干细胞移植于梗死心肌可以促进心肌再生和新生血管的形成,明显改善心功能。 关键词：基因转染;骨髓间充质干细胞;血管内皮生长因子;肝细胞生长因子;移植 doi:10.3969/j.issn.1673-8225.2012.10.029     

血管内皮生长因子基因转染骨髓间充质干细胞同种异体移植治疗大鼠急性心肌梗死

目的探讨同种异体血管内皮生长因子(VEGF)基因转染的骨髓间充质干细胞(MSCs)在大鼠梗死心脏局部存活、分化及对心功能的影响;明确同种异体干细胞及VEGF基因转染干细胞移植治疗急性心肌梗死(AMI)的可行性及效果。方法雄性SD大鼠30只,随机分为单纯注射培养基对照组、MSCs治疗组及VEGF基因转染MSCs治疗组。分离纯化雄性Wistar大鼠骨髓间充质干细胞(rMSCs),于左冠状动脉前降支结扎1h后植入到SD大鼠心组织,移植4周后检测心功能并取心脏行组织染色检查。结果异体大鼠MSCs可在梗死心组织定居、生存;免疫组化检测MSCs转化为心肌细胞及血管内皮细胞;与对照组比较VEGF基因转染异体细胞移植组左室射血分数升高(P<0.05),梗死边缘区心肌面毛细血管数目明显增加(P<0.05)。结论同种异体VEGF基因转染MSCs移植治疗AMI可行、有效。     

Bone marrow mesenchymal stem cells overexpressing human basic fibroblast growth factor increase vasculogenesis in ischemic rats

Administration or expression of growth factors, as well as implantation of autologous bone marrow cells, promote in vivo angiogenesis. This study investigated the angiogenic potential of combining both approaches through the allogenic transplantation of bone marrow-derived mesenchymal stem cells (MSCs) expressing human basic fibroblast growth factor (hbFGF). After establishing a hind limb ischemia model in Sprague Dawley rats, the animals were randomly divided into four treatment groups: MSCs expressing green fluorescent protein (GFP-MSC), MSCs expressing hbFGF (hbFGF-MSC), MSC controls, and phosphate-buffered saline (PBS) controls. After 2 weeks, MSC survival and differentiation, hbFGF and vascular endothelial growth factor (VEGF) expression, and microvessel density of ischemic muscles were determined. Stable hbFGF expression was observed in the hbFGF-MSC group after 2 weeks. More hbFGF-MSCs than GFP-MSCs survived and differentiated into vascular endothelial cells (P<0.001); however, their differentiation rates were similar. Moreover, allogenic transplantation of hbFGF-MSCs increased VEGF expression (P=0.008) and microvessel density (P<0.001). Transplantation of hbFGF-expressing MSCs promoted angiogenesis in an in vivo hind limb ischemia model by increasing the survival of transplanted cells that subsequently differentiated into vascular endothelial cells. This study showed the therapeutic potential of combining cell-based therapy with gene therapy to treat ischemic disease.     

自体骨髓基质干细胞移植治疗兔缺血心肌的实验研究

目的：用一种接近临床的骨髓移植模型，观察骨髓基质干细胞（MSCs）移植到缺血心肌后是否在心肌的微环境中可以向心肌细胞分化，提高心功能。 方法： 采用自体MSCs移植的方法，MSCs在体外培养扩增。在通过结扎冠状动脉造成心肌缺血1周后，MSCs被5溴-2脱氧尿苷（BrdU)标记后移植到自体的缺血心肌中。 结果： 移植4周后，MSCs向心肌细胞分化，表达出α-横纹肌肌动蛋白（sarcomeric actin），缺血区血管密度明显增加，左室收缩功能明显强于对照组。 结论： MSCs移植可以提高缺血心肌的心功能可能和MSCs向心肌细胞分化有关。     

血红素氧合酶-1修饰的骨髓间充质干细胞心肌移植对梗死后心肌细胞凋亡及左心室功能的影响

目的： 探讨血红素氧合酶-1(HO-1)修饰的骨髓间充质干细胞(MSCs)对心肌梗死后心肌细胞凋亡及左心室功能的影响。方法: 取大鼠骨髓,体外分离扩增培养MSCs,HO-1腺病毒转染。结扎左前降支1 h后,分别将HO-1-MSCs、MSCs多点注射到大鼠心脏梗死区周边,对照组注射等量PBS。移植后第4 d,Western blotting检测梗死区周边HO-1蛋白、促凋亡蛋白Bax的表达;ELISA检测梗死区周边组织细胞因子血管内皮生长因子(VEGF)、b-成纤维生长因子(bFGF)的表达,第7 d超声心动图检测各组大鼠心功能变化。4周后,取梗死区周边心肌行Masson染色和免疫组化CD34因子染色。结果: Adv-HO-1转染MSCs后获稳定表达;HO-1蛋白在HO-1-MSCs组的表达明显高于MSCs组和对照组(P<0.01);促凋亡蛋白Bax的表达明显低于其它2组(P<0.01);细胞因子VEGF、bFGF的表达不同程度地高于其它2组(P<0.01)。HO-1-MSCs组左室收缩功能各项指标明显优于其它2组(P<0.01)。移植4周后,HO-1-MSCs组梗死区周边毛细血管密度明显高于MSCs组和对照组(P<0.01),HO-1-MSCs组心室壁变厚,心室腔明显缩小,胶原蛋白沉积减少。结论: HO-1修饰的MSCs分泌细胞因子协同HO-1蛋白抑制心肌细胞凋亡,促血管新生,抑制心室重构,改善心功能。     

骨髓间充质干细胞膜微粒促进大鼠心肌梗死后血管新生

目的:观察骨髓间充质干细胞膜微粒(MSC-MPs)对大鼠心肌梗死后血管新生以及心功能的影响。方法:提取Sprague-Dawley大鼠MSCs并培养,在低氧低营养条件下培养72 h,以诱导细胞凋亡释放MSC-MPs。将培养上清液超速离心获取MSC-MPs,透射电镜下观察其大小及形态,并用流式细胞术分析其表型。建立SD大鼠心肌梗死模型,心肌梗死边缘区注射膜微粒及对照试剂。超声心动图检测心功能,Masson染色检测心梗面积,免疫组织化学染色技术检测梗死边缘区血管α-平滑肌肌动蛋白和von Willebrand因子以确定血管新生情况,real-time PCR检测心梗组织中血管内皮生长因子(VEGF)表达变化。结果:MSCs凋亡后可以释放膜微粒,MSC-MPs来自MSCs,直径为100~1 000 nm。心肌梗死大鼠心肌内注射MSC-MPs后,第7天和第28天时心功能明显改善,第28 d时心梗面积比对照组减小,新生血管密度明显增加,第7天时心梗组织VEGF的表达增加。结论:MSC-MPs可以促进大鼠心肌梗死后的血管新生,改善心功能。     

Monocyte chemotactic protein 1 increases homing of mesenchymal stem cell to injured myocardium and neovascularization following myocardial infarction

Objective:To investigate the effect of MCP-1 on mesenchymal stem cells(MSCs) homing to injured myocardium in a rat myocardial infarction(MI) model. Methods:Rat myocardial infarction model was established by permanent left anterior descending branch ligation. Mesenchymal stem cells from donor rats were cultured in IMDM and labeled with BrdU. The Rats were divided into two groups. Monocyte chemotactic protein 1(MCP-1) expression were measured by in situ hybridization and immunohistochemistry in the sham operated or infarcted hearts at 1,2, 4,7,14 and 28 days post operation in MCP-1 detection group. The rats were injected with MCP-1, anti-MCP-1 antibody or saline 4 days after myocardial infarction in intervention group. Then, a total of 5 × 106 cells in 2.5 ml of PBS were injected through the tail vein. The number of the labeled MSCs in the infarcted hearts was counted 3 days post injection. Cardiac function and blood vessel density were assessed 28 days post injection. Results:Self-generating MCP-1 expression was increased at the first day, peaked at the 7th day and decreased thereafter post MI and remained unchanged in sham operated hearts. The MSCs enrichment in the host hearts were more abundant in the MI groups than that in the non-Mi group(P = 0.000), the MSCs enrichment in the host hearts were more abundant in the MCP-1 injected group than that in the anti-MCP-1 antibody and saline injected groups (P = 0.000). Cardiac function was improved more in MCP-1 injected group than anti-MCP-1 antibody and saline injected groups(P= 0.000). Neovascularization in MCP-1 injected group significantly increased compared with that of other groups(P = 0.000). Conclusion: Myocardial MCP-1 expression was increased only in the early phase post MI. MCP-1 may enhance MSCs homing to the injured heart and improve cardiac function by promoting neovascularization.     

Adenovirus-mediated transfer of VEGF into marrow stromal cells combined with PLGA/TCP scaffold increases vascularization and promotes bone repair in vivo

Introduction

Large osseous defect remains a serious clinical problem due to the lack of sufficient blood supply and it has been proposed that this situation can be relieved by accelerating the formation of new vessels in the process of bone defect repair. The aim of this study was to develop a new type of artificial bone by transferring the VEGF gene into marrow stromal cells (MSCs) and seeding them into a porous scaffold.

Material and methods

An adenovirus vector was employed to transfer the VEGF gene into MSCs and expression of the exogenous gene was confirmed by ELISA. Next the transduced cells were seeded into a collagen I modified PLGA/TCP scaffold. The constructed new complex artificial bone was then assessed for biocompatibility in vitro and blood vessel formation and bone formation in vivo.

Results

We found that adenovirus mediated VEGF gene transfer into MSCs sustained VEGF expression in MSCs for 3 weeks. Porous scaffold PLGA/TCP made by rapid prototyping technology exhibited improved biocompatibility resulting from crosslinking with collagen I. Furthermore, the in vivo study showed that large amounts of blood vessels were detected histologically 1 week after artificial bone implantation, and significant bone formation was detected 8 weeks after implantation.

Conclusions

Our findings suggest that gene transfer of VEGF into MSCs combined with PLGA/TCP scaffold enhances bone repair in vivo by promoting vascularization.     

血管内皮生长因子基因转染的心肌细胞移植对心肌梗死大鼠心功能的影响

目的：探讨腺病毒介导血管内皮生长因子165基因（AdVEGF165）转染乳鼠心肌细胞后血管内皮生长因子（VEGF）的表达及移植于大鼠急性心肌梗死（MI）模型后对心功能的影响。方法:体外培养新生大鼠心室肌细胞、标记BrdU、共培养法转染AdVEGF165基因；收集培养液上清，ELISA法检测转染细胞VEGF的表达。结扎同种大鼠前降支建立心肌梗死模型，4周后将心肌梗死大鼠随机分为4组，分别注射移植转染心肌细胞(组Ⅰ)、单纯心肌细胞（组Ⅱ）、AdVEGF165（组Ⅲ）和DMEM培养基（组Ⅳ）。超声心动图检测移植前及移植4周后的心功能。处死大鼠，留取心脏标本作HE病理染色及免疫组化检测，并计数血管密度。结果:AdVEGF165基因转染的心肌细胞表达VEGF高于对照组(P<0.01)；超声检测心功能提示转染细胞组(组Ⅰ)心功能障碍轻于其它3组（P<0.01）；免疫组化检测显示，移植细胞在移植区存活；HE染色血管计数显示转染组(组Ⅰ)有更多的新生血管形成（P<0.01） 。结论：AdVEGF165基因转染心肌细胞后表达分泌VEGF增加，可促进梗死区新生血管形成，改善心肌血供，有利于移植细胞的存活，能更好地减轻心功能障碍。     

骨髓间充质干细胞和心脏Sca1阳性细胞移植治疗心肌梗死的效果比较及其机制研究

目的探讨骨髓来源的间充质干细胞(MSCs)和心脏来源的Sca1阳性干细胞移植对小鼠急性心肌梗死后的心功能恢复的影响。方法分别从成年C57BL/C小鼠的骨髓分离获取骨髓间充质干细胞,从心脏利用流式分选获取Sca1阳性干细胞,并在体外进行培养、扩增。C57BL/C小鼠雄性小鼠24只,按照以下方式分组,每组6只,假手术组,生理盐水对照组,MSCs治疗组和Sca1阳性细胞治疗组。小鼠麻醉后开胸,利用结扎心脏冠状动脉的左前降支建立急性心肌梗死模型,建模成功后分别在梗死区周围心肌内注射上述细胞或者生理盐水,假手术组小鼠不结扎冠状动脉。4周后,利用心脏超声观察小鼠左心室射血分数(LVEF)以及左心室舒张末期容积,以此评估心功能改变。细胞培养至第4代,采用荧光半定量PCR的方式分析细胞表达血管内皮生长因子(VEGFa和VEGFb)的情况。结果分离培养的骨髓MSCs贴壁生长,呈梭形;Sca1阳性干细胞在心脏组织的阳性率约为18%,培养后细胞贴壁生长,成短梭形,形态较MSCs更饱满。在细胞移植治疗后,与Sca1阳性干细胞治疗相比,MSCs治疗可以增加心梗后小鼠的存活率。细胞移植治疗4周后,骨髓来源MSCs治疗组的LVEF明显高于心脏来源Sca1阳性干细胞,且更有利于减少心梗后左心室舒张末期容积的扩大,改善心肌重塑。骨髓来源的MSCs表达VEGFa和VEGFb明显高于Sca1阳性细胞。结论心脏来源的Sca1阳性干细胞和骨髓来源的MSCs均可提高LVEF,促进心功能的恢复,且后者优于前者,这可能与MSCs高表达VEGF有关。     

心肌梗死大鼠缺血心肌中内皮抑素的表达

目的： 观察心肌梗死后大鼠不同时间缺血心肌中内皮抑素的表达及其与新生血管密度和血管内皮生长因子（VEGF）的关系。 方法： 32只心肌梗死SD大鼠随机分为心肌梗死后7、14、21、28 d 4个组，以假手术组作为正常对照组，每组8只。应用免疫组织化学染色方法，观察各组心肌梗死大鼠缺血心肌中内皮抑素、VEGF 的表达和新生血管密度。 结果： 心肌梗死大鼠缺血心肌中内皮抑素的表达明显增加，弥散分部于心肌细胞和组织间隙，第7 d表达量最高，至14、21、28 d表达量逐渐降低，28 d基本降至基础水平，与VEGF表达的变化趋势一致，并与新生血管密度相关。 结论： 内皮抑素在心肌梗死大鼠的缺血心肌中表达增加，与VEGF的动态变化一致，并与新生血管密度呈正相关，提示内皮抑素可能参与缺血心肌血管新生的调节。     

兔骨髓间充质干细胞来源的心肌(样)细胞的诱导分化研究

目的体外诱导骨髓间充质干细胞(Mesenchymal stem cells,MSCs)向肌源性细胞分化,探索诱导后的MSCs移植于心肌梗死区的存活和分化情况。方法提取、分离、培养兔的MSCs。经5-氮胞苷诱导后,进行免疫组化,电镜观察。4',6二乙酞基-2-苯基吲哚(DAPI)标记MSCs,建立兔心肌梗死模型。实验动物随机分两组:实验组(n=10)在心梗区域注入经诱导后的MSCs;对照组(n=10)在心梗区域注入不含MSCs的培养液。移植4周后,进行病理标本观察和免疫组化检测。结果5-氮胞苷诱导MSCs4周,部分细胞表达肌钙蛋白T(troponin T),电镜观察到肌丝形成。MSCs在体外用DAPI标记,用荧光显微镜观察细胞发蓝色荧光。移植4周后,在实验组中用荧光显微镜观察可见梗死区组织标本中可见DAPI标记带蓝色荧光的供体细胞核,移植细胞表达troponin T。结论MSCs经5-氮胞苷诱导后可向心肌细胞转化。移植细胞可在心肌存活,并向心肌细胞(样)转化。     

骨髓间充质干细胞介导的血红素氧合酶-1促进大鼠心肌梗死后血管再生简

 目的 探讨骨髓间充质干细胞 (MSCs) 介导的血红素氧合酶-1 (HO-1) 对心肌梗死后心 脏血管再生及左心室功能的影响。方法 取大鼠骨髓,体外分离扩增培养 MSCs,HO-1 腺病毒转染。结扎左前降支 1 h 后,分别将 HO-1-MSCs、MSCs 多点注射到大鼠心肌梗死区周边,对照组注射等量 PBS。 结果 MSCs 介导的HO-1能在体外及体内获得稳定表达;HO-1-MSCs组促血管生长因子VEGF、FGF2的表达及毛细血管密度明显高于 MSCs 组和对照组 (P < 0.01);但促血管再生的作用可被HO抑制剂阻断。HO-1-MSCs组心肌细胞凋亡及纤维化明显低于MSCs 组和对照组 (P < 0.01);HO-1-MSCs组左室收缩功能各项指标明显优于其他两组(P < 0.01)。HO-1-MSCs组心室壁变厚,心室腔明显缩小。结论 MSCs介导的血红素氧合酶-1能促进心肌梗死后心脏血管再生,改善左心室功能。     

Coronary Flow Reserve in the Remote Myocardium Predicts Left Ventricular Remodeling Following Acute Myocardial Infarction

Purpose

Coronary flow reserve (CFR) in the non-infarcted myocardium is often impaired following acute myocardial infarction (AMI). However, the clinical significance of CFR in the non-infarcted myocardium is not fully understood. The objective of the present study was to assess whether a relationship exists between CFR and left ventricular remodeling following AMI.

Materials and Methods

We enrolled 18 consecutive patients undergoing coronary intervention. Heart function was analyzed using real-time myocardial contrast echocardiography at one week and six months after coronary angioplasty. Ten subjects were enrolled as the control group and were examined using the same method at the same time to assess CFR. Cardiac troponin I (cTnI) levels were routinely analyzed to estimate peak concentration.

Results

CFR was 1.55±0.11 in the infarcted zone and 2.05±0.31 in the remote zone (p<0.01) at one week following AMI. According to CFR values in the remote zone, all patients were divided into two groups: Group I (CFR <2.05) and Group II (CFR >2.05). The levels of cTnI were higher in Group I compared to Group II on admission (36.40 vs. 21.38, p<0.05). Furthermore, left ventricular end diastolic volume was higher in Group I compared to Group II at six months following coronary angioplasty.

Conclusion

Microvascular dysfunction is commonly observed in the remote myocardium. The CFR value accurately predicts adverse ventricular remodeling following AMI.     

同种异体骨髓单个核细胞移植治疗大鼠急性心肌梗死实验研究

目的探讨大鼠同种异体骨髓单个核细胞（bone marrow mononuclear cells，BM—MNCs）在急性心肌梗死区分化增殖潜能及其修复重建心肌作用。方法健康雄性Wistar大鼠24只，用结扎冠状动脉左前降支的方法建立大鼠心肌梗死模型，随机分为对照组（AMI＋培养基，12只），移植组（AMI＋BM—MNCs，12只）；分别将制备的培养基和BM—MNCs悬液心外膜下植入梗死心肌周围。移植术后4周，观察心肌梗死区及其周边区组织形态学特点、心肌梗死面积变化。结果实验组与对照组相比心肌梗死面积明显缩小（P〈0．01）；实验组心肌梗死区内有BrdU标记阳性的BM—MNCs移植细胞存活，向心肌源性细胞分化并且诱导了大量的新生毛细血管。结论同种异体BM—MNCs移植在细胞水平完成了对心肌梗死区再心肌化和再血管化过程，可以改善急性心肌梗死后的心脏功能。     

骨髓干细胞动员与移植治疗心肌梗死的比较

目的：比较骨髓干细胞动员与骨髓单个核细胞移植对兔心肌梗死的治疗作用，探讨更有效、更适用的干细胞治疗心肌梗死的方法。 方法： 将30只新西兰兔采用结扎前降支的方法复制心肌梗死模型，随机分为动员组、移植组和对照组，动员组（n=10）心梗后3 h开始皮下注射粒细胞集落刺激因子（G-CSF）30 μg·kg-1·d-1，连续使用5 d，第5 d抽取静脉血约10 mL，分离单个核细胞(BMCs)用5-溴脱氧尿嘧啶核苷（BrdU）标记后，经静脉注入动物体内。移植组（n=10）心梗后7-10 d，抽取骨髓3-5 mL,分离MNCs用BrdU标记，然后开胸将细胞移植至梗死区，对照组（n=10）不采取任何治疗措施。心梗后1周及5周采用超声心动图（UCG）检查心脏功能变化，5周时作血液动力学测定，取心脏作免疫组织化学鉴定。 结果： 心梗后5周，动员组左室射血分数（EF）明显高于1周时，移植组无变化，对照组显著下降。5周时动员组及移植组左室舒张末压（LVEDP）、+dp/dtmax和-dp/dtmax与对照组相比均有显著差异。动员组及移植组在心肌梗死区均发现有BrdU标记的阳性细胞，两组梗塞区血管密度明显高于对照组，但均未发现有新生的平滑肌细胞及心肌细胞。 结论： 骨髓干细胞动员及BMCs移植治疗心肌梗死，均能通过促进梗死区血管新生，明显改善心脏功能，骨髓干细胞动员可能为心肌梗死的治疗提供一种新的无创性手段。     

人生长激素基因修饰的鼠骨骼肌成肌细胞移植对心肌梗死大鼠血流动力学的影响

目的：探讨人生长激素（hGH）基因修饰的鼠骨骼肌成肌细胞移植对心肌梗死大鼠血流动力学和血管新生的影响。方法: 结扎大鼠左冠状动脉前降支制作大鼠心力衰竭模型。2周后将冠脉结扎后存活的30只大鼠随机分为3组,hGH基因修饰的成肌细胞移植组（hGH组）、绿色荧光蛋白(GFP)基因修饰的成肌细胞移植组（GFP组）、注射等体积培养液的对照组。治疗4周后,血流动力学检查各组心功能指标;心肌组织进行HE染色检测心肌梗死面积,Ⅷ因子免疫组织化学检测血管新生。RT-PCR检测bax和bcl〖STBX〗-2〖STBZ〗 mRNA的表达。Western blotting检测各组心肌hGH、血管内皮生长因子（VEGF）、caspase-3蛋白表达情况。结果: （1）与对照组和GFP组相比： hGH组血流动力学指标明显改善,心肌梗死面积缩小。（2）心肌组织Ⅷ因子免疫组织化学检查结果显示： hGH组血管密度显著高于GFP组和对照组。（3）RT-PCR检测结果显示hGH组bax mRNA水平显著低于GFP组和对照组, bcl-2 mRNA水平显著高于GFP组和对照组。（4）Western blotting检测结果显示hGH组大鼠心肌组织有hGH蛋白表达,其余两组心肌组织无hGH蛋白表达。与其它两组相比,hGH组caspase-3蛋白表达降低, VEGF蛋白表达增加。结论: hGH基因修饰的成肌细胞移植可以抑制细胞凋亡,与单独成肌细胞治疗相比可以诱导更大的血管化,更好地缩小心肌梗死面积,并改善心肌梗死大鼠血流动力学。成肌细胞治疗联合hGH基因治疗为心肌梗死后心力衰竭的治疗提供了一个新的途径。     

同种异体脂肪组织源性间质干细胞移植治疗大鼠急性心肌梗死

目的：建立体外分离扩增脂肪组织源性间质干细胞方法，并探讨同种异体脂肪干细胞移植治疗大鼠心肌梗死的效果及可行性。方法: 18只雄性SD大鼠随机分为假手术组、急性心肌梗死对照组（AMI组）及AMI+细胞移植组。分离大鼠腹部脂肪组织干细胞，体外扩增，BrdU标记后于结扎左冠状动脉前降支后1h移植入梗死心肌，移植后4周进行血流动力学检测心功能并取出心脏进行病理切片观察和免疫组织化学染色检测移植细胞在梗死心脏中的定居、存活情况。结果: 大鼠腹部脂肪组织可分离培养出大量间质干细胞。细胞移植治疗组左心室收缩压高于AMI对照组（P＜0.01），舒张末压显著降低（P＜0.01），左心室内压最大上升、下降速率明显加快（P＜0.05）；病理组织切片显示梗死边缘区心肌面毛细血管计数明显增加，梗死区心肌组织内及毛细血管壁中均可见移植标记细胞。结论: 脂肪组织可作为干细胞又一新的来源，同种异体脂肪干细胞移植治疗AMI有效、可行。     

Bioreducible polymer-transfected skeletal myoblasts for VEGF delivery to acutely ischemic myocardium

Implantation of skeletal myoblasts to the heart has been investigated as a means to regenerate and protect the myocardium from damage after myocardial infarction. While several animal studies utilizing skeletal myoblasts have reported positive findings, results from clinical studies have been mixed. In this study we utilize a newly developed bioreducible polymer system to transfect skeletal myoblasts with a plasmid encoding vascular endothelial growth factor (VEGF) prior to implantation into acutely ischemic myocardium. VEGF has been demonstrated to promote revascularization of the myocardium following myocardial infarction. We report that implanting VEGF expressing skeletal myoblasts into acutely ischemic myocardium produces superior results compared to implantation of untransfected skeletal myoblasts. Skeletal myoblasts expressing secreted VEGF were able to restore cardiac function to non-diseased levels as measured by ejection fraction, to limit remodeling of the heart chamber as measured by end systolic and diastolic volumes, and to prevent myocardial wall thinning. Additionally, arteriole and capillary formation, retention of viable cardiomyocytes, and prevention of apoptosis was significantly improved by VEGF expressing skeletal myoblasts compared to untransfected myoblasts. This work demonstrates the feasibility of using bioreducible cationic polymers to create engineered skeletal myoblasts to treat acutely ischemic myocardium.