Relationship Between Total Cholesterol Of Erythrocyte Membranes And Plaque Stability Of Coronary Lesions

Objective: To study the changes of total cholesterol from erythrocyte membranes (CEM)in patients with coronary artery disease(CAD)and the relationship between the CEM and plaque qualities and lesions type; and investigate the relationship between the CEM and plaque stability of coronary lesions.Background: Plaque rupture in ACS depends at least partly on the volume of the necrotic lipid core. Histopathologic studies have suggested that cholesterol transported by erythrocytes and deposited into the necrotic core of atheromatous plaques contributes to lipid core growth.Methods: 1.A cohort of 182 patients were chosen, 51patients were stable angina(SA), 81patients were acute coronary syndrome (ACS), we assessed 50 individuals with atypical chest pain and normal coronary arteries on angiography and MSCT who were considered to represent a control group.2. 97 patients with CAD underwent coronary angiography(CAG) were chosen, which stenosis of the coronary artery was 50% or greater from one or more of left main coronary artery (LM), left anterior descending artery(LAD), left circumflex artery(LCX) and right coronary artery (RCA). The morphology of coronary artery lesions on coronary angiography(CAG) was categorized as follow: Type I; Type II and TypeⅢlesions. The severity of coronary artery stenosis on CAG was categorized as follow: mild stenosis; middle stenosis; severe stenosis. 70 patients underwent 64-multidetector computed tomography angiography (MSCT) examinations too, MSCT was used to analyze the qualities of plaque including soft plaques, fibrous plaques and calcified plaques. CEM was measured using an enzymatic assay, and protein content was assessed by the biuret method. 3. Routine biochemical measurements such as red blood cell(RBC),serum lipid and hypersensitive C-reactive protein(HSCRP) were abtained. The SPSS 16.0 ststistical software package was used for all calculations, A Pvalue﹤0.05 was considered to indicate statistical significance. Results for continuous variables are presented as means and SD or as medians and interquartile ranges(P75-P25) if the distributions were skewed and as percentages for categorical data. Normality was tested using the Kolmogorov-Smirnov Test. The 2-tailed unpaired Student t test or the Mann-Whitney U test were used to evaluate difference in continuous variables between the 2 groups. Analysis of variance with covariates(ANCOVA) were used to evaluate difference in continuous variables between the 3 groups. Comparisons between categorical variables were performed with the chi-square test or Fisher exact test as appropriate. continuous variables with skewed distribution were assessed as nonparametric tests. Multiple logistic regression analysis was used to assess relationship between risk factors,biochemical measuremens and ACS. Correlation analysis between CEM level and serum TC,TG,LDL,HDL,apoA1,apoB,LP(a)and HSCRP level was carried out by Spearman's correlation coefficient.Results: 1) The CEM was significantly higher in the ACS patients than that in non-CAD and stable CAD patients(P﹤0.001), did not differ in the non-CAD groups compared with that in stable CAD patients (P=0.13); The CEM in typeⅡgroup was significantly higher than that in typeⅠand in typeⅢgroup(P<0.001), the CEM did not differ in typeⅠgroupscompared with that in typeⅢgroups (P=0.24).2) The results of Multiple logistic regression analysis showed that increased CEM and HSCRP level were predictive markers of ACS(P﹤0.001).3) The CEM was positive correlation with soft plaques(r=0.52, P﹤0.001); typeⅡlesions(r=0.431, P﹤0.001)and hypersensitive C-reactive protein (HSCRP)(r=0.2,P=0.03), but negative correlation with fibrous plaques(r=-0.446, P﹤0.001); calcified plaques (r=-0.255, P=0.002)and typeⅠlesions(r=-0.446, P﹤0.001).4)The CEM was not correlation with serum TCConclusions: The CEM was close relationship with plaque stability of coronary lesions and a new predictive marker of atheromatous plaque growth and vulnerability.