Objective-High-density lipoprotein (HDL) is a heterogeneous lipoprotein class and there is no consensus on the value of HDL subspecies in coronary heart disease (CHD) risk assessment. We tested the hypothesis whether specific HDL subpopulations are significantly associated with CHD-prevalence. Methods and Results-ApoA-I concentrations (mg/dL) in HDL subpopulations were quantitatively determined by native 2d gel electrophoresis, immunoblotting, and image analysis in male participants in the Framingham Offspring Study (FOS). CHD cases (nϭ169) had higher pre␤-1 and ␣-3 particle and lower ␣-1, pre␣-3, and pre␣-1 particle levels than either all (nϭ1277) or HDL cholesterol-matched (nϭ358) controls. ␣-1 and pre␣-3 levels had an inverse association, whereas ␣-3 and pre␣-1 particle levels had a positive association with CHD prevalence after adjusting the data for established CHD risk factors. Standardized logit coefficients indicated that ␣-1 HDL was most significantly associated with CHD prevalence. Moreover, each mg/dL increase in ␣-1 particle level decreased odds of CHD by 26% (PϽ0.0001), whereas each mg/dL increase in HDL cholesterol decreased odds of CHD by 2% in a model including all established CHD risk factors. Conclusions-Specific HDL subpopulations were positively correlated, whereas others were inversely correlated with CHD prevalence in male subject in the FOS, indicating that the various HDL particles might have different roles in the cause of CHD. [1][2][3][4] Traditionally, HDL has been separated into major subclasses by polyanion precipitation, ultracentrifugation (HDL2 and HDL3), or by the apolipoprotein content, distinguishing particles containing only apoA-I (LpA-I), the major apolipoprotein of HDL, from particles containing both apoA-I and apoA-II (LpA-I:A-II). None of these techniques has provided any convincing evidence that 1 kind of HDL subfraction has any greater cardioprotective function than another. [5][6][7][8][9][10] The lack of agreement among these studies is probably related to the fact that all of these HDL subfractions are themselves heterogeneous, containing a variety of different HDL subspecies with possibly different physiological functions.Our laboratory uses native 2-dimensional gel electrophoresis, immunoblotting, and image analysis to separate HDL subpopulations quantitatively from plasma with highresolution based on electrophoretic charge and particle size. 11 We determine apoA-I content, not cholesterol, in these particles. This method has been useful in studies of HDL metabolism and cholesterol transport from cells because it separates intermediates in these processes. 12 A small casecontrol study indicated that coronary heart disease (CHD) patients not only had HDL deficiency but also had a major rearrangement in the apoA-I-containing HDL subpopulations with significantly lower levels of the large ␣-1 and pre␣-1 (Ϸ11 nm), and higher levels of the small ␣-3 (Ϸ8.4 nm) and pre␤-1 (Ϸ5.6 nm) HDL particles than controls. 13 Among these particles, ␣-3 contains both apoA-I and apoA-...

An altered HDL subpopulation profile marked with low alpha-1 and alpha-2 levels and a high alpha-3 level in coronary heart disease patients indicated an elevated risk for new CVD events. Moreover, alpha-1 and alpha-2 levels were superior to HDL-C levels in risk assessment in patients with low HDL-C in VA-HIT.