Klimov A N, Nagornev V A, Lovyagina T N
Paroi Arterielle. 1981;7(2):47-57.
The aortic endothelium of rabbits, fed an atherogenic diet, has been studied by electron microscopy and by analysis of the distribution of intravenously injected, labeled, LDL and VLDL in plasma and aortic wall. It has been proposed that, in experimental hypercholesterolemia, when the receptor mechanism of lipoprotein uptake is saturated, a receptor-independent endocytosis plays the main role in the uptake of lipoproteins particles by endothelial cells. It has been established that, during the early stages of experimental hypercholesterolemia and atherosclerosis, there was an increase in the number of vesicles of 100-250 A in diameter, even up to 750 A, in the endothelial cells. Thus, it seems probable that there is transendothelial passage, not only of LDL, but also of particles like VLDL. Furthermore, the electron microscopy data have shown the possible formation of transedothelial canals by fusion of 3-4 vesicles. As hypercholesterolemia and atherosclerosis increase, the transport of lipoproteins occurs mostly through intercellular spaces and impaired endothelial regions. The intravenous administration to rabbits of LDL and VLDL, labeled with 14C-palmitic acid in their outer shell (phospholipids) and core (triglycerides + esters of cholesterol), has revealed a preferential penetration of small lipoprotein particles and of phospholipid-rich triglyceride-poor residues, both in normal and atherosclerotic aortas.
通过电子显微镜以及对静脉注射的、标记的低密度脂蛋白（LDL）和极低密度脂蛋白（VLDL）在血浆和主动脉壁中的分布分析，对喂食致动脉粥样硬化饮食的兔子的主动脉内皮进行了研究。有人提出，在实验性高胆固醇血症中，当脂蛋白摄取的受体机制饱和时，一种不依赖受体的内吞作用在内皮细胞摄取脂蛋白颗粒中起主要作用。已经确定，在实验性高胆固醇血症和动脉粥样硬化的早期阶段，内皮细胞中直径为100 - 250埃甚至可达750埃的小泡数量增加。因此，不仅LDL，而且像VLDL这样的颗粒似乎都有可能发生跨内皮通道运输。此外，电子显微镜数据显示，3 - 4个小泡融合可能形成跨内皮通道。随着高胆固醇血症和动脉粥样硬化的加剧，脂蛋白的运输主要通过细胞间隙和受损的内皮区域进行。给兔子静脉注射外壳（磷脂）和核心（甘油三酯 + 胆固醇酯）用14C - 棕榈酸标记的LDL和VLDL，结果显示，在正常和动脉粥样硬化的主动脉中，小脂蛋白颗粒以及富含磷脂、甘油三酯含量低的残留物都有优先渗透现象。
