By Thomas S. May
HELSINKI, FINLAND -- June 14, 2007 -- According to a new study presented here at the 76th Congress of the European Atherosclerosis Society (EAS), high-density cholesterol (HDL-C) levels decrease following the ingestion of a high-fat-load meal, and this postprandial drop in "good" cholesterol is not affected by lipid-lowering therapy in subjects with the metabolic syndrome.
"The metabolic syndrome is characterized by a clustering of obesity-associated risk factors, such as elevated blood pressure, elevated triglycerides and low plasma levels of HDL-C," said Frank Visseren, MD, PhD, senior researcher at the Department of Vascular Medicine, Utrecht University Medical Center, Utrecht, The Netherlands. Dr. Visseren is head of the research group that conducted the study.
"In metabolic syndrome and in insulin resistant subjects, postprandial dyslipidemia is characterized by prolonged presence of triglyceride-rich lipoprotein particles, which leads to atherosclerosis," Dr. Visseren explained. "However, little is known about postprandial HDL-C metabolism in these patients," he noted.
To investigate HDL-C metabolism in patients with the metabolic syndrome, Dr. Visseren's group conducted a randomised crossover trial comparing the effects of 6 weeks of treatment with simvastatin 80 mg or simvastatin/ezetimibe (10 mg/10 mg) on postprandial lipid metabolism in 19 male patients with the metabolic syndrome, as defined by the Adult Treatment Panel (ATPIII). HDL-C plasma concentration and plasma cholesteryl ester transfer (CET) were measured for a period of 8 hours before and after ingestion of a high-fat-load meal.
The investigators found that HDL-C concentrations remained stable during 8 hours of fasting. However, the high-fat-load meal induced a 15% drop in HDL-C plasma levels. Total CET increased from 10.86 ± 3.83 to 13.38 ± 4.58 nmol/ml/hr, then returned to baseline. The drop in postprandial HDL-C concentrations was not affected by simvastatin or simvastatin/ezetimibe therapy.
According to Dr. Visseren, these results show that in subjects with the metabolic syndrome, regardless of lipid lowering therapy, postprandial HDL-C levels decrease in a model of acute hypertriglyceridemia, due to an increase in the cholesteryl ester transfer (CET). "CET is the process in which HDL-C particles exchange cholestryl esters for triglycerides with other lipoproteins and is facilitated by the CET protein," Dr. Visseren explained.
In conclusion, Dr. Visseren stressed that it is important for clinicians to realise that measuring fasting HDL-C in daily practice in metabolic syndrome patients gives only "part of the picture." "A decrease in postprandial HDL-C levels -- on top of already low fasting HDL-C levels -- further contributes to the increased cardiovascular risk for metabolic syndrome patients."
[Presentation title: HDL-Cholesterol Plasma Concentrations Drop in Postprandial Phase in Metabolic Syndrome Patients and Is Not Affected by Lipid Lowering Therapy. Abstract P789]
E-Mail this DGDispatch to a colleague
