脐血血管内皮祖细胞移植对心肌梗死血管形成的影响

背景：人体内存在一种能以血管发生方式形成新生血管的内皮祖细胞，更新了传统意义上的出生后血管生成、血管损伤修复的理论。目的：观察犬脐血血管内皮祖细胞移植对梗死心肌血管形成的影响。设计、时间及地点：细胞学体内实验，于2006-05/2007-03在新华医院实验中心完成。材料：接近足月的妊娠杂种犬1只，用于制备脐血血管内皮祖细胞；成年犬36只，随机分为细胞移植组、模型对照组，18只/组。方法：2组犬均于冠状动脉前降支第1对角支分出后结扎建立急性心肌梗死模型。细胞移植组向冠状动脉内注射含5×106个血管内皮祖细胞(经BrdU标记)的生理盐水2 mL，模型对照组同法注射单纯等量生理盐水。移植后1，4，8周处死取材。主要观察指标：心肌标本苏木精-伊红染色确认梗死模型，BrdU免疫组化染色观察心肌血管新生情况，vW因子染色观察梗死心肌血管数。结果：心肌梗死区可见大量的瘢痕组织、成纤维细胞以及小血管形成。细胞移植组梗死心肌区小血管上可见部分细胞核内有棕黄色颗粒，BrdU呈阳性表达；模型对照组无明显新生血管。细胞移植组在心肌缺血区和梗死区血管内皮细胞的胞浆内有棕黄色颗粒，vW因子呈阳性表达；模型对照组不表达vW因子。心肌梗死后第1，4，8周，细胞移植组和模型对照组的心肌缺血区、梗死区的血管数均无明显差异(P > 0.05)。结论：犬脐血血管内皮祖细胞移植至梗死心肌后可参与血管形成，但尚不能够促进心肌的血管再生。

Effects of umbilical cord blood endothelial progenitor cell transplantation on angiogenesis following myocardial infarction

BACKGROUND: Endothelial progenitor cells are the cells that can form new blood vessels in the way of angiogenesis in the body, which updates the conventional theory of angiogenesis, vascular damage and repair after birth and provides new ideas for research and treatment of ischemic diseases. OBJECTIVE: To investigate the effects of dog umbilical cord blood endothelial progenitor cell (UCB-EPC) transplantation on angiogenesis after myocardial infarction. DESIGN, TIME AND SETTING: An in vivo cytological experiment was performed at the Laboratory Center of Xinhua Hospital between May 2006 and March 2007.MATERIALS: One full-term pregnant hybrid dog was included for preparation of UCB-EPCs. Thirty-six adult dogs were randomly divided into a cell transplantation group (n = 18) and a model control group (n = 18). METHODS: Acute myocardial infarction model was established in each group by ligation of anterior descending coronary artery. In the cell transplantation group, 2 mL physiological saline containing 5×106 BrdU-labeled EPCs was injected into the coronary artery, while in the model control group, simple physiological saline of the same amount was given. At 1, 4, and 8 weeks after transplantation, dogs were sacrificed for harvesting myocardial tissue. MAIN OUTCOME MEASURES: Myocardial infarction was confirmed by hematoxylin-eosin staining. Myocardial angiogenesis was observed by BrdU immunohistochemical staining. The number of infarcted myocardial vessels was calculated by von Willebrand (vW) factor staining. RESULTS: There was plenty of scar tissue, fibroblasts, and small vessels in the myocardial infarction region. In the cell transplantation group, brown yellow particles (BrdU-positive expression) appeared in some nuclei in small vessels from infarcted myocardium. Newly formed vessels were not found in the model control group. In the cell transplantation group, brown yellow particles (vW factor-positive expression) appeared in the cytoplasm of the vascular endothelial cells in the myocardial ischemia and infarction regions. vW factors were not expressed in the model control group. At 1, 4, and 8 weeks after myocardial infarction, there was no significant difference in vessel counts no matter in myocardial ischemia region or in myocardial infarction region between the cell transplantation and model control groups. CONCLUSION: EPCs derived from UCB of pregnant dog can participate in the formation of blood vessels but can not promote angiogenesis after acute myocardial infarction.