Abstract 5107 Circulating Retinol-Binding Protein 4 and Presence of Subclinical Cardiovascular Disease
Retinol-binding protein 4 (RBP4), a novel adipokine, has been associated with subclinical and prevalent clinical cardiovascular disease (CVD) in two small prior studies. We tested the hypothesis that circulating RBP4 would be related to presence of subclinical CVD in a large community-based sample of elderly, comprehensively characterized with measures of subclinical CVD in different compartments. We evaluated associations of serum RBP4 to subclinical CVD assessed by echocardiography, carotid artery ultrasound, brachial artery ultrasound, and invasive forearm endothelial measurements in 890 70-year old participants (51% women) of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). In multivariable-adjusted analyses (adjusting for sex, body mass index, systolic blood pressure, anti-hypertensive medication, log plasma glucose, total cholesterol, high-density lipoprotein cholesterol, creatinine, and current smoking), we observed highly significant inverse associations of RBP4 with intima-media (β, −0.40; 95% confidence interval, −0.57, −0.23) and plaque (β, −0.42; 95% confidence interval, −0.72, −0.12) gray scale median. These associations remained statistically significant and borderline significant after adjustment for multiple comparisons using bootstrap methods (empirical P, 0.0001 and 0.056, respectively). Circulating RBP4 concentrations were inversely associated with intima-media and plaque gray scale median in the carotid arteries. Gray scale median is a measure of echogenicity of the vessel wall, and a lower value has been suggested to represent a higher fat content. These findings imply that RBP4 could be involved in pathogenesis of CVD. Further studies are needed to validate these associations and to evaluate the clinical implications of our findings.