Thymosin β4 is an essential paracrine factor of embryonic endothelial progenitor cell-mediated cardioprotection
Thymosin β4 is an essential paracrine factor of embryonic endothelial progenitor cell-mediated cardioprotection
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DOI：
10.1161/circulationaha.107.758904
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发表时间：
2008-04-29
期刊：
影响因子：
37.8
通讯作者：
Kupatt, Christian
中科院分区：
文献类型：
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作者：
Hinkel, Rabea;El-Aouni, Chiraz;Kupatt, Christian
背景-尽管成功进行血运重建，但长期心肌缺血会导致心肌细胞丢失。我们报道了胚胎内皮祖细胞（eEPC）的逆行应用提供了针对缺血再灌注损伤的快速旁分泌保护。在这里，我们研究了胸腺素β4（Tβ4）作为eEPC介导的心脏保护介质的作用。方法和结果-在体外，在存在或不存在eEPC的情况下，在有或没有Tβ4短发夹RNA（shRNA）转染的情况下，对新生大鼠心肌细胞进行缺氧复氧。在体内，猪（每组 n = 9）在第一天接受经皮左前降支动脉闭塞 60 分钟。缺血 55 分钟后，将对照 eEPC（5 x 10(6) 细胞）或转染 T beta 4 shRNA 的细胞（当需要时）或单独 15 mg T beta 4 回输至前室间静脉。 24小时后测定150bpm心房起搏时梗塞区的节段性心内膜缩短、梗塞面积（氯化三苯基四氮唑活力和亚甲蓝排除）和炎症细胞流入（髓过氧化物酶活性）。应用 eEPC 后，新生大鼠心肌细胞的存活率从 32 +/- 4% 增加到 90 +/- 2%，与 T beta 4 (45 +/- 7%) 相比，这种效应对 shRNA 转染敏感。在体内，梗死面积随着 eEPC 的应用而减小（38 +/- 4% 相对于危险区域的 54 +/- 4%；P < 0.01），T beta 4 shRNA 消除了这一效应（62 +/- 3%）。 eEPC 治疗后节段性心内膜下缩短得到改善（对照区域为 22 +/- 3% 对比 -3 +/- 4%），除非转染 T beta 4 shRNA (-6 +/- 4%)。 T beta 4 的回输模拟了 eEPC 应用（梗死面积，37 +/- 3%；节段性心内膜缩短，34 +/- 7%）。髓过氧化物酶活性（对照组为 3323 +/- 388 U/mg）被 eEPC（1996 +/- 546 U/mg）或单独的 T beta 4（1455 +/- 197 U/mg）降低，但 T beta 4 shRNA 处理的 eEPC（5449 +/- 829 U/mg）没有降低。结论 - 我们的研究结果表明，局部应用髓过氧化物酶可产生短期心脏保护作用。 eEPC 至少部分归因于 T beta 4。
Background - Prolonged myocardial ischemia results in cardiomyocyte loss despite successful revascularization. We have reported that retrograde application of embryonic endothelial progenitor cells (eEPCs) provides rapid paracrine protection against ischemia-reperfusion injury. Here, we investigated the role of thymosin beta 4 (T beta 4) as a mediator of eEPC-mediated cardioprotection.Methods and Results - In vitro, neonatal rat cardiomyocytes were subjected to hypoxia-reoxygenation in the absence or presence of eEPCs with or without T beta 4 short hairpin RNA (shRNA) transfection. In vivo, pigs (n = 9 per group) underwent percutaneous left anterior descending artery occlusion for 60 minutes on day 1. After 55 minutes of ischemia, control eEPCs (5 x 10(6) cells) or cells transfected with T beta 4 shRNA when indicated or 15 mg T beta 4 alone were retroinfused into the anterior interventricular vein. Segmental endocardial shortening in the infarct zone at 150-bpm atrial pacing, infarct size (triphenyl tetrazolium chloride viability and methylene blue exclusion), and inflammatory cell influx (myeloperoxidase activity) were determined 24 hours later. Survival of neonatal rat cardiomyocytes increased from 32 +/- 4% to 90 +/- 2% after eEPC application, an effect sensitive to shRNA transfection compared with T beta 4 (45 +/- 7%). In vivo, infarct size decreased with eEPC application (38 +/- 4% versus 54 +/- 4% of area at risk; P < 0.01), an effect abolished by T beta 4 shRNA (62 +/- 3%). Segmental subendocardial shortening improved after eEPC treatment (22 +/- 3% versus -3 +/- 4% of control area) unless T beta 4 shRNA was transfected (-6 +/- 4%). Retroinfusion of T beta 4 mimicked eEPC application (infarct size, 37 +/- 3%; segmental endocardial shortening, 34 +/- 7%). Myeloperoxidase activity (3323 +/- 388 U/mg in controls) was decreased by eEPCs (1996 +/- 546 U/mg) or T beta 4 alone (1455 +/- 197 U/mg) but not T beta 4 shRNA-treated eEPCs (5449 +/- 829 U/mg).Conclusion - Our findings show that short-term cardioprotection derived by regional application of eEPCs can be attributed, at least in part, to T beta 4.