靶向拮抗P-选择素预防急性心肌梗死再灌注损伤的实验研究

Endothelial cells, platelets and white blood cells could aggregate with each other to trigger the local inflammatory reaction in the vascular damaged area. And this was the pathophysiological basis of reperfusion injury after acute myocardial infarction.The key factor to trigger and promote aggregation of these cells was the high concentration of P-selectin in the local damaged area. So if P-selectin could be antagonisted in the local impaired area specifically, the reperfusion injury would be prevented effectively. PSGL-1 analogues had been regarded as the most potential clinical application of P-selectin antagonist. However, the efficacy of general PSGL-1 analogues would be limitted due to lack of targeting, which were unable to bind to the local damaged area accurately and efficiently, and unable to achieve a effective therapeutic concentrations in the local damaged area. There were a huge number of apoptotic cells in the tissue of reperfusion injury, and annexin-V could make a targeted combination to these apoptotic cells. Our previous study have built the rPSGL-annexin-V fusion protein, which has the dual function of targeted combination to the local damaged area and specific antagonism of P-selectin in vitro experiments. Our current study intends to study the effect of this fusion protein to prevent reperfusion injury in vivo experiments. If successful, the research results may provide a new effective treatment for reperfusion injury after acute myocardial infarction.

内皮细胞、血小板、白细胞相互聚合，可以促发血管受损局部的炎症反应，是急性心肌梗死再灌注损伤的主要病理生理学基础。受损局部高浓度的P-选择素是触发和推动上述三种细胞聚合的关键因素，如能特异性地拮抗受损局部P-选择素的作用，就能有效预防再灌注损伤的发生。PSGL-1类似物被视作最有临床应用前景的P-选择素拮抗剂，但由于缺乏靶向性，一般的PSGL-1类似物无法准确、高效地结合到受损局部，在受损局部无法达到有效的治疗浓度，从而治疗效果有限。再灌注时的受损局部富含凋亡细胞，annexin-V能够靶向性地结合凋亡细胞。前期研究已构建出rPSGL-annexin-V融合蛋白，体外研究显示其具备靶向性结合受损局部和特异性拮抗P-选择素的双重功能。本研究拟建立动物模型，研究这种融合蛋白在活体动物中预防再灌注损伤的作用。如获成功，有可能为急性心肌梗死再灌注治疗提供一种新的有效的辅助治疗手段。

内皮细胞、血小板、白细胞相互聚合，可以促发血管受损局部的炎症反应，是急性心肌梗死再灌注损伤的主要病理生理学基础。受损局部高浓度的 P-选择素是触发和推动上述三种细胞聚合的关键因素.特异性地拮抗受损局部 P-选择素的作用能有效预防再灌注损伤的发生。本项目构建SSL5-Annexin V融合蛋白的表达体系，并评价其抗炎及抗血栓功能。研究显示融合蛋白具备靶向性结合受损局部和特异性拮抗 P-选择素的双重功能，能够有效阻止炎性环境中内皮细胞对炎性细胞的趋化作用，减少炎症环境下炎性细胞的滞留；同时融合蛋白能够阻止炎性环境下活化血小板与炎性细胞的黏附，阻止血栓生成。另外融合细胞可以阻止部分中心粒细胞陷阱的形成，从旁路阻止炎性级联反应及血栓形成。本项目揭示了融合蛋白SSL5-Annexin V治疗急性心肌梗死再灌注损伤的可能性，为其提供一种有效的辅助治疗手段。

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