Lipid transfers to HDL are predictors of precocious clinical coronary heart disease

BackgroundHigh-density-lipoprotein (HDL) has several antiatherogenic properties and, although the concentration of HDL-cholesterol negatively correlates with incidence of coronary artery disease (CAD), this is not sufficient to evaluate the overall HDL protective role. The aim was to investigate whether precocious CAD patients show abnormalities in lipid transfers to HDL, a fundamental step in HDL metabolism and function.MethodsThirty normocholesterolemic CAD patients aged < 50 y and 30 controls paired for sex, age and B.M.I. were studied. Fasting blood samples were collected for the in vitro lipid transfer assay and plasma lipid determination. A donor nanoemulsion labeled with radioactive free-cholesterol, cholesteryl esters, phospholipids and triglycerides was incubated with whole plasma and after chemical precipitation of non-HDL fractions, supernatant was counted for radioactivity in HDL.ResultsLDL and HDL-cholesterol and triglycerides were equal in both groups. Transfers of free-cholesterol (3.8 ± 1.2%vs 7.0 ± 3.3%,p < 0.0001) and triglycerides (3.7 ± 1.7%vs 4.9 ± 1.9%, p = 0.0125) were diminished in CAD patients whereas cholesteryl ester transfer increased (6.5 ± 1.9%vs 4.8 ± 1.8%, p = 0.0008); phospholipid transfer was equal (17.8 ± 3.5% vs19.5 ± 3.9%).ConclusionAlterations in the transfer of lipids to HDL may constitute a new marker for precocious CAD and relation of this metabolic alteration with HDL antiatherogenic function should be investigated in future studies.