同型半胱氨酸作用于正常个体血小板凝聚反应的体外研究

目的　研究人体血清或血浆同型半胱氨酸 (HCY)的升高与血小板高凝状态的关系。方法　全血或浓缩血小板与不同浓度的 HCY于 37℃ (用于血小板凝聚检测 )或 2 2～ 2 5℃ [用于血小板纤维原结合及 P-选择素 (P- selectin)表达的检测 ]作用 15 min,后应用血小板凝聚仪和流式细胞仪分别检测 HCY对血小板活性的作用。结果　 HCY在浓度 30 μm ol/ L 时能增加一磷酸腺苷 (ADP)和胶原诱导的全血和浓缩血小板凝聚反应 [(3.0± 0 .8) Ω/ min vs(5 .0± 2 .0 ) Ω/ m in,P<0 .0 5 ,n=9和 (8.5± 1.5 ) Ω/ min vs(11± 2 .5 ) Ω/ min,P<0 .0 5 ,n=6 ],但在浓度 10 0 0μm ol/ L时却抑制 ADP和胶原诱导的全血和浓缩血小板凝聚反应 [(7.0± 4 .0 )Ω vs (3.6± 2 .6 )Ω和 (6 .8± 2 .2 )Ω vs (4.1± 3.3)Ω ,P<0 .0 5 ,n=9],血小板凝聚性的改变并不伴随血小板纤维原结合及 P- selectin表达的变化。结论　体外实验表明 HCY能协同促进已激活的血小板凝聚反应 ,可能是 HCY与体内血栓形成有关的机理之一

In vitro study of homocysteine on platelet aggregation in healthy Chinese subjects

Objective To examine the effects of homocysteine (HCY) on platelet aggregation in vitro at levels similar to moderately elevated in vivo levels and higher concentrations. Methods The effects of HCY at a variety of concentrations on platelet aggregation, platelet fibrinogen binding and P-selectin expression were tested with and without addition of agonists (ADP, collagen) in 25 healthy participants after platelet-rich plasma (PRP) or whole blood was incubated with HCY for 15 minutes at 37℃ or room temperature. Results HCY alone failed to induce platelet aggregation in either whole blood or PRP. However, HCY (30±mol/L) slightly, but significantly, increased platelet aggregation (slope of aggregation) induced by ADP at 20 μmol/L in whole blood [(3.0±0.8) vs (5.0±2.0) ohm/ min, n=9] and collagen (2 μg/ml) in PRP [(8.5±1.5) vs (11±2.5) ohm/ min, n=6]. However, at higher concentrations of up to 1000 μmol/L, HCY significantly decreased whole blood platelet aggregation induced by ADP[ (7.0±4.0) vs (3.6±2.6) and (6.8±2.2) vs (4.1±3.3) ohms 10 and 20 μmol/L, respectively, P<0.05, n=9). Conclusion In the presence of natural agonists HCY (30 μmol/L final concentration) potentiated platelet aggregation in PRP and whole blood.