Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, China.
Amino Acids. 2012 Sep;43(3):1243-50. doi: 10.1007/s00726-011-1196-4. Epub 2011 Dec 13.
Total elevated plasma homocysteine (Hcy) is a risk factor for thromboembolism. Vascular endothelium is important to regulate coagulation, but the impact of Hcy on the clot-promoting activity (CPA) of endothelial cells has not been fully understood. In our study, human umbilical vein endothelial cells (HUVECs) were treated with Hcy (8, 20, 80, 200, 800 μmol/L) for 24 h. Annexin V was utilized to detect phosphatidylserine (PS) externalization and endothelial microparticles (MPs) formation. CPA was assessed by recalcification time and purified clotting complex tests. We found that Hcy enhanced the externalized PS and consequent CPA of HUVECs in a dose-dependent fashion, effect of Hcy had statistical significance at 800 μmol/L. In addition, Hcy also increased the shedding of procoagulant endothelial MPs. Blocking of PS with 128 nmol/L annexin V reduced approximately 70% CPA of HUVECs and endothelial MPs, but human anti-tissue factor antibody had little inhibitive effect. Our results showed that Hcy increased CPA of HUVECs via PS externalization and MPs release. Our present study has implications for hyperhomocysteinemia-related hypercoagulability.
血浆同型半胱氨酸（Hcy）升高是血栓栓塞的危险因素。血管内皮对凝血的调节具有重要意义，但 Hcy 对内皮细胞促凝活性（CPA）的影响尚未完全阐明。在我们的研究中，用人脐静脉内皮细胞（HUVEC）处理 Hcy（8、20、80、200、800μmol/L）24 小时。用 Annexin V 检测磷脂酰丝氨酸（PS）外翻和内皮微颗粒（MPs）形成。通过复钙时间和纯化凝血复合物试验评估 CPA。结果发现 Hcy 以剂量依赖性方式增强 HUVECs 的 PS 外翻和随后的 CPA，在 800μmol/L 时 Hcy 的作用具有统计学意义。此外，Hcy 还增加了促凝内皮 MPs 的脱落。用 128nmol/L Annexin V 阻断 PS 可使 HUVECs 和内皮 MPs 的 CPA 降低约 70%，但人抗组织因子抗体的抑制作用很小。我们的研究结果表明，Hcy 通过 PS 外翻和 MPs 释放增加 HUVECs 的 CPA。本研究对高同型半胱氨酸血症相关高凝状态具有重要意义。
