Total cholesterol content of erythrocyte membranes in acute coronary syndrome: correlation with apolipoprotein A-I and lipoprotein (a)

OBJECTIVES: Recent studies reported that total cholesterol erythrocyte membrane (CEM) levels were associated with the presence of acute coronary syndrome (ACS). However, little is known about the mechanisms of CEM elevation in these patients. The aim of this study was to investigate the association between CEM and the circulating lipid profile to delineate the possible mechanisms of CEM elevation in patients with ACS. METHODS: CEM levels, serum concentrations of triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, lipoprotein (a), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), and high-sensitive C-reactive protein levels were measured in 418 Chinese patients undergoing coronary artery angiography, including ACS (n=311) and stable angina pectoris (n=107). RESULTS: CEM levels in the ACS group were significantly higher (median, 129.82; interquartile range, 110.99-156.54 μg/mg, P<0.001) compared with the stable angina pectoris group (median, 80.88; interquartile range, 66.69-98.57 μg/mg). Multivariable logistic regression analyses showed a significantly independent relationship between CEM levels and the presence of ACS (odds ratio, 10.257; 95% confidence interval, 5.380-19.556, P<0.001). CEM levels were positively correlated with plasma lipoprotein (a) levels (r=0.175; P<0.001) and negatively correlated with serum Apo A-I levels (r=-0.149; P=0.002). CONCLUSION: CEM levels are closely associated with the occurrence of ACS as an independent determinant. The correlation of CEM with lipoprotein (a) and Apo A-I suggests that changes to these lipid proteins could be one possible mechanism for CEM increase in patients with ACS.