Octogenarian Subjects Have Low Postprandial Levels of Chylomicron Remnants: A Possible Explanation for Protection Against Atherosclerosis

Abstract

Postprandial lipoprotein metabolism may play an important role in the development of atherosclerosis. It is widely believed that in healthy octogenarians, the atherogenic process occurs very slowly. In the present study, postprandial lipoprotein metabolism was examined in 14 octogenarian subjects (mean age, 84 +/- 4.2 years) and 19 younger controls (mean age, 50 +/- 4.8 years) using the vitamin A-fat loading test, in which intestinally derived lipoproteins are specifically labeled with retinyl palmitate (RP). Results indicated that mean peak chylomicron remnant RP levels and the areas below the chylomicron remnant RP curve were significantly lower in the octogenarian group than in the controls (625 +/- 329 vs 1321 +/- 688 micrograms/L and 3740 +/- 1078 vs 6162 +/- 1063 micrograms/L.h, respectively; p < .0001). No differences were found between the two groups in chylomicron RP levels or in lipolytic activity. The study suggests that octogenarians do not exhibit the decrease in chylomicron lipolysis that usually accompanies aging. In addition, these subjects have significantly lower levels of chylomicron remnants in the circulation. Since accumulation of these particles has been implicated in the development of atherogenesis, our findings may indicate a major mechanism of atherosclerosis prevention in healthy octogenarians.

Lipoprotein Profile and High-Density Lipoproteins: Subfractions Distribution in Centenarians

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Clearance of chylomicron remnants in normolipidaemic patients with coronary artery disease: case control study over three years

“…Zilversmit was the first to publish this hypothesis,5 which was followed by many confirmatory studies. Most, however, were small and provided only indirect support by showing correlations between postprandial lipoprotein metabolism and other well known risk factors for coronary artery disease 16 17 18 19 20. Only one study found that coronary artery disease patients with normal fasting lipid values had higher concentrations of postprandial lipoproteins than patients without coronary artery disease 21.…”

Effects of chylomicrons and chylomicron remnants on endothelium-dependent relaxation of rat aorta

“…Secondly, octogenarian subjects without any evidence of vascular disease exhibit low postprandial lev-Ž . els of chylomicron remnants Weintraub et al, 1992 . Thirdly, patients with familial hyperchylomicronaemia, previously thought to be resistant to atheroma development because of low circulating LDL concentrations, do develop Ž .…”