高半胱氨酸对血管内皮细胞、血小板聚集和肝素辅助因子活性效应的实验研究

Effects of homocysteine on human vascular endothelial cells, platelet aggregation and heparin cofactor activity

目的 揭示高半胱氨酸（ Ｈｃｙ） 致血栓形成的机制。方法 ①免疫荧光分析血管内皮细胞凝血酶调节蛋白（ Ｔ Ｍ） 抗原分布；②发色基质法测定肝素辅助因子Ⅱ（ Ｈ ＣⅡ） 活性。结果 ① Ｈｃｙ 可下调血管内皮细胞表面 Ｔ Ｍ 的表达，且呈浓度依赖性；② Ｈｃｙ 对 Ａ Ｄ Ｐ 和凝血酶诱导的血小板聚集均无影响；③在正常人血浆体系中， 以肝素和硫酸皮肤素（ Ｄ Ｓ） 为激动剂， Ｈｃｙ 对血浆 Ａ ＴⅢ和 Ｈ ＣⅡ的抗凝血酶活性无明显影响， 在纯化的 Ａ ＴⅢ体系， Ｈｃｙ 对 Ａ ＴⅢ的抗凝血酶作用也无影响。结论 Ｈｃｙ 的致血栓效应与其对内皮细胞 Ｔ Ｍ 表达调节有关，且独立于血小板聚集功能和肝素辅助因子活性变化。

Objectives To elucidate partly the mechanism of homocysteine associated thrombosis. Methods ①Thrombomodulin (TM ) antigen distribution on human vascular endothelial cell (EC)membrane was assayed by immune fluorescence histochemistry stain and flow cytometry; ②Plasma heparin cofactor activity was measured by chromogenic method. Results Homocysteine (Hcy) significantly down regulated the expression of TM on EC, with a concentration dependent manner; ②Hcy did not influence platelet aggregation induced by ADP and thrombin; ③Hcy exerted no effects on the activities of antithrombin Ⅲ or heparin cofactor. Conclusion The effect of Hcy in developing thrombosis may be associated with an inhibitory action on EC TM expression;which was independent of platelet aggregation or heparin cofactor activity.