Sheng Zu-Long, Yao Yu-Yu, Li Ye-Fei, Fu Cong, Ma Gen-Shan
Department of Cardiology, Zhongda Hospital, Medical School of Southeast University 87 Dingjiaqiao, Nanjing, Jiangsu, 210009, China.
Am J Transl Res. 2015 Jul 15;7(7):1214-26. eCollection 2015.
This study determines whether preconditioning (PC) of human endothelial progenitor cells (hEPCs) with bradykinin promotes infarcted myocardium repair via enhanced activation of B2 receptor (B2R)-dependent Akt/eNOS and increased angiogenesis. hEPCs with or without bradykinin preconditioning (BK-PC) were transplanted into a nude mouse model of acute myocardial infarction. Survival of transplanted cells was assessed using DiD-labeled hEPCs. Infarct size, cardiac function, and angiogenesis were measured 10 d after transplantation. Akt, eNOS, and vascular endothelial growth factor (VEGF) expressions in cardiac tissues were detected by western blotting, and NO production was determined using an NO assay kit. The cell migration and tube formation in cultured hEPCs were determined using transwell chamber and matrigel tube formation assays, respectively. The VEGF levels in the cell supernatant were measured using an enzyme-linked immunosorbent assay kit. BK-PC-hEPCs improved cardiac function, decreased infarct size, and promoted neovascularization 10 d following transplantation. PC increased Akt and eNOS phosphorylation, VEGF expression, and NO production in the ischemic myocardium. The effects of BK-PC were abrogated by HOE140 (B2R antagonist) and LY294002 (Akt antagonist). PC increased hEPC migration, tube formation, and VEGF levels in vitro. Activation of B2R-dependent Akt/eNOS phosphorylation by BK-PC promotes hEPC neovascularization and improves cardiac function following transplantation.
本研究旨在确定用缓激肽对人内皮祖细胞（hEPCs）进行预处理（PC）是否通过增强B2受体（B2R）依赖性Akt/eNOS的激活和增加血管生成来促进梗死心肌的修复。将经过或未经过缓激肽预处理（BK-PC）的hEPCs移植到急性心肌梗死的裸鼠模型中。使用DiD标记的hEPCs评估移植细胞的存活情况。在移植后10天测量梗死面积、心脏功能和血管生成。通过蛋白质印迹法检测心脏组织中Akt、eNOS和血管内皮生长因子（VEGF）的表达，并使用NO检测试剂盒测定NO的产生。分别使用Transwell小室和基质胶管形成试验测定培养的hEPCs中的细胞迁移和管形成。使用酶联免疫吸附测定试剂盒测量细胞上清液中的VEGF水平。BK-PC-hEPCs在移植后10天改善了心脏功能，减小了梗死面积，并促进了新生血管形成。预处理增加了缺血心肌中Akt和eNOS的磷酸化、VEGF表达以及NO的产生。HOE140（B2R拮抗剂）和LY294002（Akt拮抗剂）消除了BK-PC的作用。预处理在体外增加了hEPC的迁移、管形成和VEGF水平。BK-PC对B2R依赖性Akt/eNOS磷酸化的激活促进了hEPC的新生血管形成，并改善了移植后的心脏功能。
