Kojima S, Homma Y, Sakane H, Kobayashi T, Ozawa H, Okajima Y
Tokai University, School of Medicine, Kanagawa, Japan.
Tokai J Exp Clin Med. 1996 Dec;21(4-6):165-9.
Hyperlipoproteinemic subjects with apo(lipoprotein)E4 are usually hypercholesterolemic and those with apoE2 are hypertriglyceridemic. We report a case of moderate hypertriglyceridemia with apoE phenotype E4/3. Plasma levels of total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL)-C, apoAI, apoB, apoCII, apoCIII, and apoE were 200mg/dL, 451 mg/dL, 31 mg/dL, 115 mg/dL, 99 mg/dL, 10.0 mg/dL, 22.2 mg/dL, and 12.0 mg/dL, respectively. Plasma levels of very low density lipoprotein (VLDL)-C and intermediate density lipoprotein (IDL)-C were high, and those of low density lipoprotein (LDL)-C and HDL2-C were low. All lipoprotein subfractions except VLDL were TG-rich. These findings are common in moderate hypertriglyceridemia. The plasma level of remnant-like particle (RLP, equivalent to chylomicron remnant)-C, was high. The lipoprotein lipase which removes TG from chylomicron and VLDL was normal. The activity of LDL receptor which removes remnants of chylomicron and VLDL as well as LDL was high. ApoE4 actively binds to receptors of remnant and LDL. Thus, the removal of TG-rich lipoproteins should not be impaired in this patient. Plasma levels of insulin during oral glucose tolerance test were high. Hyperinsulinism stimulates VLDL synthesis in the liver. Subjects with apoE4 show active synthesis of chyromicron. Thus, we concluded that the moderate hypertriglyceridemia in this E4/3 patient was due to the overproduction of chylomicron and VLDL.
载脂蛋白E4的高脂蛋白血症患者通常为高胆固醇血症，而载脂蛋白E2的患者则为高甘油三酯血症。我们报告一例载脂蛋白E表型为E4/3的中度高甘油三酯血症病例。血浆总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白（HDL）-C、载脂蛋白AI、载脂蛋白B、载脂蛋白CII、载脂蛋白CIII和载脂蛋白E的水平分别为200mg/dL、451mg/dL、31mg/dL、115mg/dL、99mg/dL、10.0mg/dL、22.2mg/dL和12.0mg/dL。极低密度脂蛋白（VLDL）-C和中间密度脂蛋白（IDL）-C的血浆水平较高，而低密度脂蛋白（LDL）-C和HDL2-C的水平较低。除VLDL外，所有脂蛋白亚组分均富含TG。这些发现在中度高甘油三酯血症中很常见。残留样颗粒（RLP，相当于乳糜微粒残粒）-C的血浆水平较高。从乳糜微粒和VLDL中清除TG的脂蛋白脂肪酶正常。清除乳糜微粒和VLDL以及LDL残粒的LDL受体活性较高。载脂蛋白E4能与残粒和LDL的受体有效结合。因此，该患者富含TG的脂蛋白的清除不应受到损害。口服葡萄糖耐量试验期间的胰岛素血浆水平较高。高胰岛素血症刺激肝脏中VLDL的合成。载脂蛋白E4的受试者显示乳糜微粒的合成活跃。因此，我们得出结论，该E4/3患者的中度高甘油三酯血症是由于乳糜微粒和VLDL的过度产生所致。
