The Changes Of HDL Cholesterol Efflux Capacity In Patients With Coronary Heart Disease And Its Correlation With Content Of Erythrocyte Membranes

Background Previous studies has showed that the low level of high-densitylipoprotein Cholesterol (HDL-C) is an independent risk factor to coronary heart disease(CHD), and negative correlation exists between the level of HDL-C and the incidence ofCHD. Recently, however, increasing studies has found that the level of HDL-C couldnot reflect the overall function of the high-density lipoprotein (HDL), and suggested thefunctional activity of high-density lipoprotein, HDL cholesterol efflux capacity (HCEC),is uncorrelated with HDL-C levels, which shows negative correlation with the incidenceof coronary heart disease. However, there are not enough studies to support this point ofview. Our team has found that the total cholesterol content of erythrocyte membranes(CEM) in CHD subjects was significantly higher than control group. But the mechanismof cholesterol reverse transport in red cell membranes is still unclear. Is there anyrelationship between CEM and HCEC? There is no report about it so far..Objective To observe the difference of serum HCEC between CHD and Controlgroups, analyse the correlation between HCEC and CEM levels, and discuss why thelevels of CEM in CHD patients is higher than control group. Finally, to explore thepathophysiological mechanisms of coronary heart disease.Methods (1)201subjects with chest pain or chest tightness were assigned into twogroup according to their clinical symptoms and the results of coronary arteryangiography: CHD group(n=148)had coronary heart disease; Control group(n=53) waswith normal results of coronary artery angiography;(2) To assess the level of serum HDL cholesterol efflux capacity (HCEC) To collect whole blood during coronaryangiography process, extract serum from whole blood, choose cell culture method andtest HCEC by liquid scintillation counting.(3) To assess the amount of total cholesterolcontent of erythrocyte membranes (CEM) To collect whole blood during coronaryangiography process, extract erythrocyte membranes from the blood, and then evaluatethe levels of CEM by an enzymatic assay after.(4) Statistical analysis Continuousvariables means and standard deviations, and categorical variables were represented byfrequencies and percentages. Analyses were performed by SPSS13.0software.Results (1) HCEC level in the CHD group (1.53±0.40) was significantly lower(p=0.036) than the control group (1.67±0.46), and there was no significant difference(p=0.614) in levels of HDL-C between CHD group (1.16±0.40mmol/L) and controlgroup (1.20±0.36mmol/L);(2) CEM level in the CHD group (138.53±34.82ug/mg) wassignificantly lower (p=0.029) than the control group (121.29±25.03ug/mg);(3) HCEClevel has positive correlation with ApoA-I levels, and there was no correlation betweenHCEC and other serum lipids;(4) There was no correlation between CEM levels andother serum lipid;(5) HCEC level has negative correlation with CEM levels(r=-0.261，p<0.001).Conclusion In Coronary heart disease group, the level of serum HCEC wassignificant decreased,which has negative correlation with the high CEM level. Giventhat, the reduction of HCEC level in CHD patients may be one of the mechanisms ofreverse cholesterol transport in red blood cell.