Katzel L I, Coon P J, Busby M J, Gottlieb S O, Krauss R M, Goldberg A P
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Md.
Arterioscler Thromb. 1992 Jul;12(7):814-23. doi: 10.1161/01.atv.12.7.814.
Silent myocardial ischemia (SI), an asymptomatic manifestation of coronary artery disease (CAD), was identified in 10% of apparently healthy nonsmoking, nondiabetic older (60 +/- 7 years, mean +/- SD) men with normal plasma cholesterol levels. We hypothesized that in the absence of other major risk factors for CAD, the men with SI would have reduced plasma levels of high density lipoprotein (HDL) and HDL2 subspecies due to an upper-body fat distribution (waist-to-hip ratio [WHR]), hyperinsulinemia, and abnormal postheparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities. Compared with 47 normal control subjects of similar age, obesity, and maximal aerobic capacity, the 18 men with SI had higher plasma triglyceride (TG) (162 +/- 71 versus 102 +/- 39 mg/dl, p less than 0.001) and lower HDL-C (33 +/- 6 versus 37 +/- 7 mg/dl, p less than 0.02) levels with no difference in low density lipoprotein cholesterol level. The HDL2b and HDL2a subspecies measured by gradient gel electrophoresis were also lower in the men with SI (p less than 0.01). The plasma glucose and insulin responses during an oral glucose tolerance test were the same in both groups. Postheparin plasma HL activity was significantly higher in 12 men with SI than in 41 control subjects (34 +/- 8 versus 27 +/- 10 mumol/ml.hr-1, p less than 0.03) and was correlated with log insulin area (r = 0.36, p less than 0.05) and WHR (r = 0.32, p less than 0.05) in the control subjects but not in the men with SI. In the control group, the percent HDL2b subspecies was correlated inversely with postheparin plasma HL activity (r = -0.46, p less than 0.01, n = 41) as well as WHR (r = -0.49, p less than 0.001, n = 47) and log insulin area (r = -0.37, p less than 0.05, n = 47) but not in the men with SI. Postheparin LPL activity was the same in both groups of men and did not correlate with HDL, WHR, insulin, or plasma TG levels. As the control subjects and men with SI had comparable degrees of abdominal obesity and hyperinsulinemia, these results suggest that the reduced HDL-C levels in men with SI may be related to elevations in HL activity. Thus, abdominal obesity, hyperinsulinemia, elevated TG levels, and low HDL-C and HDL2 subspecies levels may predispose these older men to atherosclerosis.
无症状性心肌缺血（SI）是冠状动脉疾病（CAD）的一种无症状表现，在血浆胆固醇水平正常、明显健康的非吸烟、非糖尿病老年男性（60±7岁，平均值±标准差）中，有10%被发现存在该症状。我们推测，在没有其他CAD主要危险因素的情况下，患有SI的男性由于上身脂肪分布（腰臀比[WHR]）、高胰岛素血症以及肝素后血浆脂蛋白脂肪酶（LPL）和肝脂酶（HL）活性异常，其高密度脂蛋白（HDL）和HDL2亚类的血浆水平会降低。与47名年龄、肥胖程度和最大有氧能力相似的正常对照受试者相比，18名患有SI的男性血浆甘油三酯（TG）水平更高（162±71对102±39mg/dl，p<0.001），高密度脂蛋白胆固醇（HDL-C）水平更低（33±6对37±7mg/dl，p<0.02），而低密度脂蛋白胆固醇水平无差异。通过梯度凝胶电泳测量的HDL2b和HDL2a亚类在患有SI的男性中也较低（p<0.01）。两组在口服葡萄糖耐量试验期间的血浆葡萄糖和胰岛素反应相同。12名患有SI的男性的肝素后血浆HL活性显著高于41名对照受试者（34±8对27±10μmol/ml·hr-1，p<0.03），并且在对照受试者中与胰岛素面积对数（r = 0.36，p<0.05）和WHR（r = 0.32，p<0.05）相关，但在患有SI的男性中不相关。在对照组中，HDL2b亚类百分比与肝素后血浆HL活性呈负相关（r = -0.46，p<0.01，n = 41），与WHR（r = -0.49，p<0.001，n = 47）以及胰岛素面积对数（r = -0.37，p<0.05，n = 47）也呈负相关，但在患有SI的男性中不相关。两组男性的肝素后LPL活性相同，且与HDL、WHR、胰岛素或血浆TG水平均无相关性。由于对照受试者和患有SI的男性腹部肥胖和高胰岛素血症程度相当，这些结果表明，患有SI的男性HDL-C水平降低可能与HL活性升高有关。因此，腹部肥胖、高胰岛素血症、TG水平升高以及HDL-C和HDL2亚类水平降低可能使这些老年男性易患动脉粥样硬化。
