Abstract 15172: Quantitative Changes in High-Density Lipoprotein Underlie Impaired SR-B1 Mediated Efflux in Obese Individuals
Background: Obesity is associated with an adverse cardiovascular outcome. While high-density lipoprotein cholesterol (HDL-C) is often decreased in the setting of obesity, little is known regarding the potential impact of HDL functionality. The current study investigated the impact of obesity on scavenger receptor B1 (SR-B1) mediated serum cholesterol efflux.
Methods: 55 apparently healthy obese subjects (BMI>=30kg/m2) and 17 normal weight subjects underwent physical examination and fasting blood draw. The subject with history of diabetes and cardiovascular disease, and on the treatment of dyslipidemia was excluded. Serum lipid profile and capacities of serum to promote cholesterol efflux with SR-BI expressing Fu5AH hepatoma cells were examined.
Results: The characteristics of the entire cohort was, age 48.1±11.1 years, BMI 34.1±9.0, waist circumference 100.3±16.7cm, LDL-C 120.4±24.5mg/dL, HDL-C 50.1±12.3mg/dL and triglycerides 116±58.9mg/dL. While increased SR-B1 mediated cholesterol efflux capacities were observed in association with higher HDL-C (r=0.46, p<0.0001) and apolipoprotein AI (r=0.38, p=0.0009) concentrations, it was inversely correlated with waist hip ratio (r=-0.29, p=0.01). In obese subjects, 26 showed normal lipid profile and 29 subjects showed lower HDL-C and/or higher triglycerides. In the comparison between normal weight subjects and obese subjects without dyslipidemia, no differences were observed in lipid profile and also cholesterol efflux capacities (10.5±2.0 vs 10.3±1.7 %/4h, p=0.80). In the comparison within obese subjects, with or without dyslipidemia, there were no differences in age, BMI, waist circumference, blood pressure and LDL-C level. However, the group with dyslipidemia showed the impaired serum cholesterol efflux capacities (9.4±1.9 vs 10.3±1.7 %/4h, p=0.01) with increased waist hip ratio (0.9±0.1 vs 0.8±0.08, p=0.04).
Conclusion: SR-B1 mediated cholesterol efflux was impaired in accordance with dyslipidemia and increased waist hip ratio in apparently healthy obese subjects, which suggests that HDL functionality is impaired in association with HDL quantitative change and visceral obesity.
- © 2011 by American Heart Association, Inc.