Guthikonda S, Haynes W G
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242-1081, USA.
Curr Opin Cardiol. 1999 Jul;14(4):283-91. doi: 10.1097/00001573-199907000-00002.
Homocysteine is a sulfhydryl amino acid formed during metabolism of methionine. Increasing evidence suggests that homocyst(e)ine may act as an independent risk factor for ischemic heart disease, cerebrovascular disease, and peripheral arterial disease. Recent prospective data have shown that homocyst(e)ine levels in the top 20% of the population increase the risk for ischemic heart disease by approximately twofold. Homocyst(e)ine seems to promote the progression of atherosclerosis by causing endothelial dysfunction, increasing oxidant stress, and promoting vascular smooth muscle growth. Recent human studies using methionine loading to experimentally induce moderate hyperhomocyst(e)inemia have demonstrated rapid and profound impairment of resistance and conduit artery endothelial function. No data are available from randomized, controlled trials of the effects of lowering plasma homocyst(e)ine on atherosclerotic vascular events; however, screening for hyperhomocyst(e)inemia should be actively considered in individuals with progressive and unexplained atherosclerosis. Both fasting and postmethionine load homocyst(e)ine levels should be measured. B vitamins, including folic acid and vitamins B6 and B12 are the mainstay of treatment of patients with hyperhomocyst(e)inemia. Primary prevention strategies await the completion of long-term, randomized, prospective studies.
同型半胱氨酸是甲硫氨酸代谢过程中形成的一种含巯基氨基酸。越来越多的证据表明，同型半胱氨酸可能是缺血性心脏病、脑血管疾病和外周动脉疾病的独立危险因素。最近的前瞻性数据显示，同型半胱氨酸水平处于人群前20%的人，缺血性心脏病风险增加约两倍。同型半胱氨酸似乎通过引起内皮功能障碍、增加氧化应激和促进血管平滑肌生长来推动动脉粥样硬化的进展。最近利用甲硫氨酸负荷实验性诱导中度高同型半胱氨酸血症的人体研究表明，阻力动脉和输送动脉的内皮功能迅速且严重受损。关于降低血浆同型半胱氨酸对动脉粥样硬化血管事件影响的随机对照试验尚无数据；然而，对于患有进行性且原因不明的动脉粥样硬化的个体，应积极考虑筛查高同型半胱氨酸血症。应同时测量空腹和甲硫氨酸负荷后的同型半胱氨酸水平。包括叶酸、维生素B6和维生素B12在内的B族维生素是高同型半胱氨酸血症患者治疗的主要手段。一级预防策略有待长期、随机、前瞻性研究的完成。
