Hazzard W R, Porte D, Bierman E L
J Clin Invest. 1970 Oct;49(10):1853-8. doi: 10.1172/JCI106403.
Chylomicron (primary particles) were detected by polyvinylpyrollidone (PVP) flocculation in plasma collected after an overnight fast from eight hyperlipemic subjects with broad-beta disease (type III hyperlipoproteinemia). The composition of these chylomicrons was abnormal: relatively poor in triglyceride and rich in cholesterol, giving rise to a triglyceride/cholesterol ratio of < 3.0 in all cases, uniformly below the ratio in chylomicrons from eight fasting subjects with mixed lipemia. By contrast, at the peak of alimentary lipemia following an oral fat load (2 g/kg), chylomicrons from broad-beta subjects had normal, triglyceride-rich composition (triglyceride/cholesterol = 14.0) and resembled chylomicrons from subjects with mixed lipemia, endogenous lipemia, and familial hypercholesterolemia after similar fat loads. As the alimentary lipemia cleared, chylomicrons remaining in broad-beta subjects 14-24 hr after the fat load were again rich in cholesterol. However, a similar degree of cholesterol enrichment was observed in chylomicrons from the subjects with familial hypercholesterolemia, while only a minor increase in cholesterol was recorded in chylomicrons from subjects with mixed or endogenous lipemia. Parallel studies of changes in chylomicron composition during in vitro incubation of whole plasma and of S(f) > 400 with S(f) < 400 lipoproteins from subjects with the different forms of hyperlipoproteinemia revealed equal cholesterol enrichment of chylomicrons from a subject with mixed lipemia and from a subject with broad-beta disease in media of equivalent cholesterol content. These experiments suggested neither excessive avidity of chylomicrons for cholesterol uptake nor excessive influence of S(f) < 400 lipoproteins upon chylomicron composition in broad-beta disease.Thus, results in this study suggest that the cholesterol-rich chylomicrons observed in subjects with broad-beta disease after an overnight fast may originate in the intestine as particles of normal composition (chiefly dietary triglyceride) but assume a composition which is relatively rich in cholesterol through processes of lipolysis and cholesterol transfer among circulating lipoproteins which may not be unique to broad-beta disease.
通过聚乙烯吡咯烷酮（PVP）絮凝法，在8名患有宽β病（III型高脂蛋白血症）的高脂血症受试者空腹过夜后采集的血浆中检测到乳糜微粒（初级颗粒）。这些乳糜微粒的组成异常：甘油三酯相对较少，胆固醇丰富，在所有情况下甘油三酯/胆固醇比值均<3.0，始终低于8名混合性血脂异常的空腹受试者的乳糜微粒中的该比值。相比之下，口服脂肪负荷（2 g/kg）后出现食源性血脂异常高峰时，宽β病受试者的乳糜微粒具有正常的、富含甘油三酯的组成（甘油三酯/胆固醇 = 14.0），并且类似于混合性血脂异常、内源性血脂异常和家族性高胆固醇血症受试者在相似脂肪负荷后的乳糜微粒。随着食源性血脂异常消退，宽β病受试者在脂肪负荷后14 - 24小时残留的乳糜微粒再次富含胆固醇。然而，在家族性高胆固醇血症受试者的乳糜微粒中也观察到了类似程度的胆固醇富集，而在混合性或内源性血脂异常受试者的乳糜微粒中仅记录到胆固醇的少量增加。对不同形式高脂蛋白血症受试者的全血浆以及S(f)>400和S(f)<400脂蛋白进行体外孵育期间乳糜微粒组成变化的平行研究表明，在胆固醇含量相当的介质中，混合性血脂异常受试者和宽β病受试者的乳糜微粒胆固醇富集程度相同。这些实验表明，在宽β病中，乳糜微粒对胆固醇摄取既没有过度的亲和力，S(f)<400脂蛋白对乳糜微粒组成也没有过度影响。因此，本研究结果表明，宽β病受试者空腹过夜后观察到的富含胆固醇的乳糜微粒可能在肠道中以正常组成的颗粒（主要是膳食甘油三酯）形式产生，但通过脂解过程以及循环脂蛋白之间的胆固醇转移，其组成变得相对富含胆固醇，而这些过程可能并非宽β病所特有。
