Metabolism of high density lipoprotein subfractions and constituents in Tangier disease following the infusion of high density lipoproteins.

Abstract

The metabolism of apolipoproteins A-I and A-II, as well as other high density lipoprotein (HDL) constituents, was studied in patients with homozygous familial HDL deficiency (Tangier disease) prior to and after plasma exchange or HDL infusion. Mean plasma apoA-I, apoA-II, and HDL cholesterol values in homozygotes (n = 2) were 2.0 mg/dl, 2.7 mg/dl, and 1.5 mg/dl, respectively, and in a normal control subject were 125.1 mg/dl, 23.0 mg/dl, and 53.0 mg/dl, respectively. Based on radioiodinated apoA-I and apoA-II kinetic studies in the baseline state, synthesis rates for apoA-I and apoA-II in mg/kg/day were 3.81 and 1.61, respectively, in one homozygote (patient B) and 11.82 and 1.99, respectively, in the normal subject. ApoA-I and apoA-II plasma residence times in days were 0.22 and 0.81, respectively, in the homozygote, and 4.04 and 4.44, respectively, in the normal subject. These data indicate that this homozygote had both a moderate decrease in the synthetic rates of apoA-I and apoA-II, as well as a marked decrease in the plasma residence times of these two apolipoproteins. In one homozygote (patient A) following a complete plasma exchange during cardiopulmonary bypass, plasma HDL cholesterol, apoA-I, and apoA-II levels were very similar to pre-exchange values within 64 hr after exchange. A second homozygote (patient B) received HDL intravenously as well as 125I-labeled apoA-I and 131I-labeled apoA-II. Following infusion, the residence time in days for HDL subfractions, HDL2b,…