Insulin decreases plasma cholesteryl ester transfer but not cholesterol esterification in healthy subjects as well as in normotriglyceridaemic patients with type 2 diabetes

Abstract

Insulin infusion decreases plasma CET in conjunction with a fall in triglycerides but does not decrease cholesterol esterification in healthy and type 2 diabetic subjects, indicating that acute hyperinsulinaemia has a different effect on these processes involved in HDL metabolism. Despite unaltered fasting plasma CET, HDL core lipid composition was abnormal in diabetic patients, suggesting that additional mechanisms may contribute to changes in HDL metabolism in diabetes mellitus.

Cellular cholesterol efflux to plasma from moderately hypercholesterolaemic type 1 diabetic patients is enhanced, and is unaffected by simvastatin treatment

“…Plasma was obtained within 30 min by centrifugation at 1400 g for 15 min at 4°C. Total cholesterol, triglyceride and choline-containing phospholipids were measured enzymatically as described [25]. HDL was separated in fresh plasma by precipitation of apo-B-containing lipoproteins using sodium phosphotungstate/MgCl 2 .…”

“…Plasma cholesteryl ester transfer was assayed essentially as described previously [25]. In brief, [ 3 H] cholesterol was equilibrated for 24 h with plasma-free cholesterol at 4°C followed by incubation of the sample at 37°C for 3 h. Subsequently, VLDL+LDL were precipitated by addition of phosphotungstate/MgCl 2 .…”

“…Lipids were extracted from the precipitate and the cholesteryl esters were isolated on silica columns and radioactivity was counted. Plasma cholesterol esterification was determined by measurement of formation of cholesteryl esters after addition of [ H] cholesterol was obtained after incubation at 4°C for 24 h. Subsequently, the plasma was incubated at 37°C for 1 h [25]. Plasma LCAT activity was measured using excess exogenous substrate containing [ 3 H] cholesterol as described [27].…”

Fibroblast cholesterol efflux to plasma from metabolic syndrome subjects is not defective despite low high-density lipoprotein cholesterol

“…Plasma PLTP activity is related to the activity in human reference pool plasma and is expressed in arbitrary units (AU; 100 AU corresponds to 13.6 mmol phosphatidylcholine transferred, ml/h). Plasma CET was determined as described previously (29). Briefly, [ 3 H]cholesterol was equilibrated for 24 h at 4 8C with plasma cholesterol followed by incubation of plasma at 37 8C.…”

“…Thereafter, apo B-containing lipoproteins were precipitated and the labeled cholesteryl esters were separated from the labeled unesterified cholesterol on silica columns. Plasma EST was measured as the formation of cholesteryl esters after the addition of [ 3 H]cholesterol to plasma as described (29). Equilibration of added [ 3 H]cholesterol was obtained after incubation at 4 8C for 24 h. Subsequently, the plasma was incubated at 37 8C.…”