Although exercise increases HDL-cholesterol, exercise-induced changes in HDL metabolism have been little explored. Lipid transfer to HDL is essential for HDL's role in reverse cholesterol transport. We investigated the effects of acute exhaustive exercise on lipid transfer to HDL. We compared plasma lipid, apolipoprotein and cytokine levels and in vitro transfer of four lipids from a radioactively labeled lipid donor nanoemulsion to HDL in sedentary individuals (n = 28) and in marathon runners (n = 14) at baseline, immediately after and 72 h after a marathon. While HDL-cholesterol concentrations and apo A1 levels were higher in marathon runners, LDL-cholesterol, apo B and triacylglycerol levels were similar in both groups. Transfers of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.2 (4.5-6), p = 0.001], phospholipids [21.7 (20.4-22.2) vs. 8.2 (7.7-8.9), p = 0.0001] and triacylglycerol [3.7 (3.1-4) vs. 1.3 (0.8-1.7), p = 0.0001] were higher in marathon runners, but esterified-cholesterol transfer was similar. Immediately after the marathon, LDL- and HDL-cholesterol concentrations and apo A1 levels were unchanged, but apo B and triacylglycerol levels increased. Lipid transfer of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.8 (4.9-6.6), p = 0.0001], phospholipids [21.7 (20.4-22.2) vs. 19.1 (18.6-19.3), p = 0.0001], esterified-cholesterol [3.2 (2.2-3.8) vs. 2.3 (2-2.9), p = 0.02] and triacylglycerol [3.7 (3.1-4) vs. 2.6 (2.1-2.8), p = 0.0001] to HDL were all reduced immediately after the marathon but returned to baseline 72 h later. Running a marathon increased IL-6 and TNF-α levels, but after 72 h these values returned to baseline. Lipid transfer, except esterified-cholesterol transfer, was higher in marathon runners than in sedentary individuals, but the marathon itself acutely inhibited lipid transfer. In light of these novel observations, further study is required to clarify how these metabolic changes can influence HDL composition and anti-atherogenic function.

SummaryBrickground: Atherosclerotic cardiovascular disease is prevalent among renal transplant patients. Increase in serum total cholesterol, low-density lipoprotein, and very low-density lipoprotein is common in those patients. Alterations in chylomicron metabolism, however, are also related to atherogenesis and were not studied in renal transplant.Hypothesis: The aim of this study was to evaluate chylomicron metabolism in renal transplant recipients receiving cyclosporin-based immunosuppression. We determined the plasma kinetics of triglyceride-rich emulsions labeled with [ jHH]triolein and [ 14C]cholesteryl oleate that are known to mimic the chylomicron metabolism when injected into the blood stream.Mothoils: Fourteen renal transplant recipients with normal renal function ( 10 men, 4 women, aged 40 k 6. I years) and 17 age-and gender-matched healthy controls received bolus injections of the chylomicron-like emulsion. Plasma samples were then taken at regular intervals during 60 min. Disappearance curves of the labels and the respective fractional clearance rates (FCR) were calculated in order to measure lipolysis and chylomicron remnant removal from the plasma.