Metabolic heterogeneity underlying postprandial lipemia among men with lowfasting high density lipoprotein cholesterol concentrations

The high triglyceride (TG) and low high density lipoprotein (HDL) cholester ol dyslipidemia has been associated with increased postprandial lipemia. Al though fasting TG is a powerful predictor of postprandial hyperlipidemia, t he role of hypoalphalipoproteinemia in postprandial TG metabolism is uncert ain. We have studied postprandial lipemia among 63 men with low fasting pla sma HDL cholesterol concentrations (<0.9 mmol/L), but with either low (<2.0 mmol/L) or high (>2.0 mmol/L) fasting plasma TG levels. A significant rela tionship was noted between postprandial TG response and fasting HDL cholest erol concentration (r = -0.43; P < 0.0005). We also found that men with hig h TG/low HDL dyslipidemia (high TG and low HDL cholesterol; n = 16) were ch aracterized by abdominal obesity as well as increased visceral adipose tiss ue accumulation, whereas normolipidemic controls (low TG and high HDL chole sterol; n = 26) and men with isolated low HDL cholesterol concentrations (l ow TG and low HDL cholesterol; n = 17) were not characterized by features o f the insulin resistance syndrome (visceral obesity, hyperinsulinemia, and hypertriglyceridemia). Although controls and men with isolated low HDL chol esterol levels had similar postprandial lipemic responses, men with the hig h TG/low HDL dyslipidemia had a marked increase in their postprandial TG re sponses to the fat load compared with the other subgroups (P < 0.001). Men with the high TG/low HDL dyslipidemia were also characterized by higher con centrations of apolipoprotein (apo) B-48 and B-100 particles (chylomicron r emnants and very low density lipoproteins, respectively) before and during the postprandial period compared with the other subjects. These results sug gest that low HDL cholesterol concentration is a heterogeneous metabolic ph enotype that it is not associated with postprandial hyperlipidemia unless a ccompanied by other features of the insulin resistance syndrome.