The associations between high-density lipoprotein mean particle size and its fatty acid composition

Investigation of membrane fatty acid profiles in erythrocytes of patients with stable coronary artery disease

BACKGROUND

The association between the erythrocyte membrane fatty acids and the severity of coronary stenosis has not been studied in patients with stable coronary artery disease (CAD).

OBJECTIVE

We sought to investigate whether the fatty acid profile of erythrocyte membranes is significantly different in patients with stable CAD compared with patients with nonsignificant coronary stenosis and evaluate a possible relationship between fatty acid profile and the severity of coronary stenosis.

METHODS

The population included 144 patients, undergoing clinically indicated coronary angiography. The severity of coronary stenosis was scored after coronary angiography, and patients were divided into 2 groups; the S-stenosis group (CAD patients, n = 82) had a significant stenosis indicated by coronary angiography and the second group, S-stenosis (n = 62), had nonsignificant coronary stenosis.

RESULTS

The erythrocyte membranes linoleic acid (LA) levels were lower (P < .001) and the arachidonic acid (AA)-to-LA ratio, a marker of desaturase activity, were higher (P < .001) in CAD patients compared with S-stenosis patients. The CAD scores were correlated negatively with the membrane LA levels (r = -0.338; P < .001) and positively with the AA-to-LA ratio (r = 0.306; P < .001).

CONCLUSIONS

This study shows that LA levels of the erythrocyte membrane and AA-to-LA ratio are correlated with the severity of CAD.

Increased membrane lipid peroxidation and decreased Na+/K+-ATPase activity in erythrocytes of patients with stable coronary artery disease

OBJECTIVES

We aimed to determine erythrocyte membrane lipid peroxidation levels and Na/K-ATPase activity in patients with and without coronary artery disease (CAD) documented by coronary angiography.

DESIGN AND METHODS

A total of 144 patients who had undergone coronary angiography were divided into a CAD group (n=82) and a non-CAD group (control group, n=62) according to the results of coronary angiography. Lipid peroxide levels in plasma and the erythrocyte membrane were measured using a fluorimetric method. Total antioxidant status and Na/K-ATPase activity in plasma were determined using spectrophotometric methods.

RESULTS

Lipid peroxidation levels were significantly higher in the erythrocyte membrane of CAD patients compared with controls, whereas Na/K-ATPase activity was significantly lower in the erythrocyte membrane of CAD patients compared with controls. The coronary artery scores were correlated positively with membrane lipid peroxidation (r=0.324, P<0.001) and negatively with Na/K-ATPase activity (r=-0.302, P<0.001).

CONCLUSION

This study shows that the levels of membrane lipid peroxidation and Na/K-ATPase activity are correlated with the severity of CAD.

Association of the total cholesterol content of erythrocyte membranes with the severity of disease in stable coronary artery disease

Increasing evidence suggests that erythrocytes may participate in atherogenesis. We sought to investigate whether the total cholesterol content of erythrocyte membranes (CEM) is significantly different in patients with stable coronary artery disease (CAD) compared to patients with nonsignificant coronary stenosis and determine the correlation between CEM and the severity of coronary stenosis. Methods. The population included 144 patients, undergoing clinically indicated coronary angiography. The severity of coronary stenosis was scored after coronary angiography and patients were divided into two groups; the S-stenosis group (CAD patients, n = 82) had a significant stenosis indicated by coronary angiography and the second group, N-stenosis (n = 62), had nonsignificant coronary stenosis. Lipid parameters were determined by routine laboratory methods. CEM was measured using an enzymatic assay, and protein content was assessed by the modified Lowry method. Results. The mean of CEM levels was higher (P < 0.001) in stable CAD patients (137.2 µg/mg of membrane protein) compared with N-stenosis patients (110.0 µg/mg of membrane protein). The coronary artery scores were correlated positively with CEM levels (r = 0.296, P < 0.001). Conclusion. CEM levels are positively associated with the severity of CAD, meaning that CEM might contribute to the development of CAD.

Serum paraoxonase 1 activity is associated with fatty acid composition of high density lipoprotein

Introduction. Cardioprotective effect of high density lipoprotein (HDL) is, in part, dependent on its related enzyme, paraoxonase 1 (PON1). Fatty acid composition of HDL could affect its size and structure. On the other hand, PON1 activity is directly related to the structure of HDL. This study was designed to investigate the association between serum PON1 activity and fatty acid composition of HDL in healthy men. Methods. One hundred and forty healthy men participated in this research. HDL was separated by sequential ultracentrifugation, and its fatty acid composition was analyzed by gas chromatography. PON1 activity was measured spectrophotometrically using paraxon as substrate. Results. Serum PON1 activity was directly correlated with the amount of stearic acid and dihomo-gamma-linolenic acid (DGLA). PON1/HDL-C was directly correlated with the amount of miristic acid, stearic acid, and DGLA and was inversely correlated with total amount of ω6 fatty acids of HDL. Conclusion. The fatty acid composition of HDL could affect the activity of its associated enzyme, PON1. As dietary fats are the major determinants of serum lipids and lipoprotein composition, consuming some special dietary fatty acids may improve the activity of PON1 and thereby have beneficial effects on health.