Hoogeveen R C, Gambhir J K, Gambhir D S, Kimball K T, Ghazzaly K, Gaubatz J W, Vaduganathan M, Rao R S, Koschinsky M, Morrisett J D
Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.
J Lipid Res. 2001 Apr;42(4):631-8.
Conventional risk factors for coronary heart disease (CHD) do not completely account for the observed increase in premature CHD in people from the Indian subcontinent or for Asian Indians who have immigrated to the USA. The objective of this study was to determine the effect of immigration to the USA on plasma levels of lipoprotein [a] (Lp[a]) and other independent risk factors for CHD in Asian Indians. Three subject groups were studied: group 1, 57 subjects living in India and diagnosed with CHD (CHD patients); group 2, 46 subjects living in India and showing no symptoms of CHD (control subjects); group 3, 206 Asian Indians living in the USA. Fasting blood samples were drawn to determine plasma levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein [LDL cholesterol (LDL-Chol)], high density lipoprotein [HDL cholesterol (HDL-Chol)], apolipoprotein B-100 (apoB-100), and Lp[a]. Apolipoprotein [a] (apo[a]) size polymorphism was determined by immunoblotting. Plasma TG, apoB-100, and Lp[a] concentrations were higher in CHD patients than in control and USA groups. CHD patients had higher levels of TC and LDL-Chol and lower HDL-Chol than control subjects. However, the USA population had higher levels of TC, LDL-Chol, and apoB-100 and lower HDL-Chol than control subjects. Plasma Lp[a] levels were inversely correlated with the relative molecular weight of the more abundant of each subject's two apo[a] isoforms (MAI), and CHD patients showed higher frequencies of lower relative molecular weights among MAI. Our observed changes in lipid profiles suggest that immigrating to the USA may place Asian Indians at increased risk for CHD. This study suggests that elevated plasma Lp[a] confers genetic predisposition to CHD in Asian Indians, and nutritional and environmental factors further increase the risk of CHD. This is the first report implicating MAI size as a predictor for development of premature CHD in Asian Indians. Including plasma Lp[a] concentration and apo[a] phenotype in screening procedures may permit early detection and preventive treatment of CHD in this population.
冠心病（CHD）的传统风险因素并不能完全解释印度次大陆人群或移民到美国的亚洲印度人过早患冠心病的现象。本研究的目的是确定移民到美国对亚洲印度人血浆脂蛋白[a]（Lp[a]）水平及其他冠心病独立风险因素的影响。研究了三个受试者组：第1组，57名生活在印度且被诊断为冠心病的受试者（冠心病患者）；第2组，46名生活在印度且无冠心病症状的受试者（对照组）；第3组，206名生活在美国的亚洲印度人。采集空腹血样以测定血浆甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白[LDL胆固醇（LDL-Chol）]、高密度脂蛋白[HDL胆固醇（HDL-Chol）]、载脂蛋白B-100（apoB-100）和Lp[a]水平。通过免疫印迹法测定载脂蛋白[a]（apo[a]）大小多态性。冠心病患者的血浆TG、apoB-100和Lp[a]浓度高于对照组和美国组。冠心病患者的TC和LDL-Chol水平高于对照组，HDL-Chol水平低于对照组。然而，美国人群的TC、LDL-Chol和apoB-100水平高于对照组，HDL-Chol水平低于对照组。血浆Lp[a]水平与每个受试者两种apo[a]异构体中含量较高者（MAI）的相对分子量呈负相关，冠心病患者中MAI相对分子量较低的频率较高。我们观察到的血脂谱变化表明，移民到美国可能会使亚洲印度人患冠心病的风险增加。本研究表明，血浆Lp[a]升高使亚洲印度人具有患冠心病的遗传易感性，营养和环境因素会进一步增加患冠心病的风险。这是首篇将MAI大小作为亚洲印度人过早患冠心病预测指标的报道。在筛查程序中纳入血浆Lp[a]浓度和apo[a]表型可能有助于早期发现和预防该人群的冠心病。
