High density lipoprotein heterogeneity & function among Indians with coronary artery disease.

Background & objectives: Impaired high density lipoprotein (HDL) functionality has been shown to be associated with cardiovascular disease risk. The study was aimed to identify the alterations in HDL function [antioxidative activity (AOA)] and subfraction distribution between acute coronary syndrome (ACS) and stable coronary artery disease (SCAD) individuals and analysing the accuracy of HDL parameters to discriminate between the groups. Methods: HDL subfraction distribution analysis was performed in 200 coronary artery disease patients (ACS and SCAD) and 60 control individuals using dextran sulphate, heparin and manganese chloride precipitation method. In terms of HDL function, AOA was evaluated by dihydrorhodamine-based fluorescent cell-free assay and paraoxonase (PON1) enzyme paraoxonase and arylesterase activity. Results: We found that higher AOA [odds ratio (95% confidence interval {CI})]: 0.09 (0.02-0.44), P<0.01 for SCAD; 0.008 (0.001-0.07), P<0.001 for ACS and higher PON1 activity [0.22 (0.8-0.59), P<0.01 for SCAD; 0.16 (0.06-0.4), P<0.001 for ACS] were associated with a lower odds of developing coronary artery disease (CAD). AOA of apoB-depleted serum was significantly correlated with HDL2-C/HDL3-C (HDL-cholesterol) ratio in controls (r=-0.31, P=0.01) and ACS (r=-0.18, P=0.04). It was observed that AOA and HDL subfraction distribution together could discriminate between the two groups of CAD with an accuracy of 72.8 per cent (P=0.004). Interpretation & conclusions: Impaired AOA and altered subfraction distribution of HDL may be responsible for its diminished anti-athero protective activity and can discriminate between the two groups of CAD individuals.