Study on the significance of apo E in aherosclerosis

载脂蛋白E是极低密度脂蛋白、极低密度脂蛋白残留物和乳糜粒残留物的蛋白质组分之一，是致动脉粥样硬化的脂蛋白。富含甘油三酯的脂蛋白及其残留物被巨噬细胞摄取，导致胆固醇酯(CE)的积聚，进而形成泡沫细胞。载脂蛋白E作为脂蛋白受体的配体在上述过程中起着重要作用。本研究探讨载脂蛋白E在动脉粥样硬化发病机制中的意义。缺血性心脏病患者载脂蛋白E_2、E_4频率显著高于对照组。载脂蛋白E2与III型高脂蛋白血症(HLP)和高甘油三酯血症(IV型HLP)有关，而ApoE4与高胆固醇血症(IIa型和IIb型HLP)有关。因此，载脂蛋白E_2和E_4具有致动脉粥样硬化作用。我们建立了一种用聚合酶链式反应-限制性片段长度多态性方法进行载脂蛋白E基因分型的方法。载脂蛋白E_2使血浆残留物样颗粒(RLP)增加，并引起被认为是动脉粥样硬化的餐后脂血症。NIDDM和apo E_2相关高脂血症患者的RLP和富含TG的脂蛋白与对照组相比，可促进CE的合成。结论：载脂蛋白E在动脉粥样硬化中起重要作用。

Apolipoprotein E is one of the protein constituents of VLDL,VLDL remnants and chylomicron remnants, which are atherogenic lipoproteins. TG-rich lipoproteins and their remnants are taken up by macrophages and cause the accumulation of cholestervl ester (CE), and then the formation of foam cells. apo E plays an important role in the above process as a ligand for the lipoprotein receptors. The significance of Apo E in the pathogenesis of atheroscler osis was examined in this study. The frequencies of apo E2 and E4 were significantly higher in patients with ischemic heart disease than in controls. Apo E2 is associated with type III hyperlipoproteinemia (HLP) and hypertriglyceridemia (type IV HLP) , whereas apo E4 is associated with hyper-cholesterolemia (type IIa and IIb HLP). Thus, apo E2 and E4 are atherogenic. We established a method for apo E genotyping by PCR-RFLP.ApoE2 increased plasma RLP (remnant-like particles) and caused postprandial lipemia, which is thought to be atherogenic. RLP and TG-rich lipoproteins derived from NIDDM and apo E2-associated hyperlipemia enhanced the CE synthesis as compared with those derived fromcontrols. It is concluded that apo E plays an important role in atherosclerosis.