New therapy against myocardial infarction using synthetic peptides

中性粒细胞向组织内的迁移是心肌缺氧和炎症反应的中心事件。中性粒细胞的卷曲是炎症反应中中性粒细胞与血管壁相互作用的第一步，这依赖于血管内皮细胞表面颗粒膜蛋白-140(GMP-140)的表达。首先，利用体外H/R模型，我们发现在60min的缺氧和30min的复氧条件下，中性粒细胞黏附在人脐静脉内皮细胞(HUVECs)上的数量高于未经I/R刺激的黏附在HUVECs上的中性粒细胞，并且抗人GMP-140抗体预先孵育HUVEC可阻断这种黏附。此外，免疫过氧化物酶染色首次证实H/R可增强HUVECs表面GMP-140的表达。其次，利用在体大鼠心肌缺血再灌注模型，我们发现在再灌流后2小时内，白细胞开始渗入到缺血30分钟的大鼠心肌中，并首次阐明细胞间黏附分子-1(ICAM-1)在再灌流后8~96小时在毛细血管和静脉内皮细胞上的表达增强。此外，用抗细胞黏附分子的单抗(CD11a、CD11b+c、CD18和ICAM-1)预处理，不仅减少了白细胞的渗透，而且减少了再灌流心脏的梗塞面积。我们的研究表明，血管内皮细胞上GMP-140和ICAM-1的表达在I/R诱导的心肌损伤中起重要作用。

The migration of neutrophils into tissues is the central event in myocardial hypoxiareoxygenation (H/R) as well as in inflammatory responses. The rolling of neutrophils has been revealed to be the first step of the interaction of the neutrophils with the vessel wall during an inflammatory response, which is dependent of the expression of granule membrane protein-140 (GMP-140) on the surface of vascular endothelial cells. First, using an in vitro model of H/R,we showed that higher number of neutrophils adhered to human umbilical vein endothelial cells (HUVECs) subjected to 60 minutes of hypoxia followed by 30 minutes of reoxygenation compared with neutrophils adhered to HUVECs subjected to no stimulation of I/R,and that preincubation of HUVECs with anti-human GMP-140 antibody blocked these adhesion. Furthermore, immunoperoxidase staining clarified, for the first time, that H/R enhanced the expression of GMP-140 on the surface of HUVECs. Next, using an in vivo rat model of myocardial ischemiareperfusion (I/R), we indicated that within 2 hours after reperfusion leukocytes began to infiltrate into the rat myocardia subjected to 30 minutes of ischemia, and clarified, for the first time, that the expression of intercellular adhesion molecule-1 (ICAM-1) was enhanced on the capillary and venous endothelial cells from 8 to 96 hours after the start of reperfusion. Furthermore, pretreatment with individual monoclonal antibodies against cell-adhesion molecules (CD11a, CD11b+c, CD18 and ICAM-1) reduced not only the infiltration of leukocytes but also the area of infarction in the reperfused hearts. Our present study suggests that the expression of GMP-140 along with ICAM-1 on vascular endothelial cells play a critical role in myocardial injury induced by I/R.