Abstract 479: Juvenile Idiopathic Arthritis Does Not Impair ABCA-1 and SR-B1-Mediated Cholesterol Efflux Capacity
Background: Autoimmune disease in adults significantly increase atherosclerotic burden and cardiovascular risk, potentially secondary to impaired high density lipoprotein (HDL) function. It is unknown whether adolescents with autoimmune diseases such as juvenile idiopathic arthritis (JIA) demonstrate changes in HDL function. We hypothesized that patients with JIA have intact HDL functionality as measured by ATP binding cassette A1 (ABCA-1) and scavenger receptor B1 (SR-B1) mediated cholesterol efflux.
Methods: 22 patients with JIA and 14 healthy controls underwent physical examination and fasting lipid panel. Subjects with significant cardiovascular risk factors, personal or family history of early cardiovascular events, or other chronic inflammatory disease were excluded. ABCA-1 and SR-B1 mediated efflux of serum were studied using J774 macrophages and Fu5AH hepatoma cells, respectively.
Results: While JIA patients were younger than controls (14.8±4.7 y vs 21.1±6.5 y, p= 0.002), there were no other differences in risk factors, lipids, or lipoproteins. JIA patients demonstrated less SR-B1 mediated efflux (9.8±2.5 % vs 12.1±3.3%, p=0.007) than controls. However, after controlling efflux for ApoA1 level, no difference was noted (0.08±0.01% vs 0.08±0.02%, p=0.60). In contrast, no difference was observed in ABCA-1 mediated efflux (11.5±3.6% vs 11.4±4.9%, p=0.96). Analysis of JIA patients showed that presence of higher active joint counts had no effect on SR-B1 or ABCA-1 mediated efflux. In the entire cohort, HDL-C and ApoA1 levels correlated with SR-B1 mediated efflux (r=0.74 and r=0.77, respectively; both p<0.0001,), but not with ABCA-1 mediated efflux.
Conclusions: Our results suggest that the capacity for SR-B1 mediated efflux is determined by the number of carriers present, while ABCA-1 mediated efflux is independent of carrier levels. In addition, the results show that patients with JIA have intact capacity for cholesterol efflux via ABCA-1 and SR-B1. Our study is the first to demonstrate that, despite ongoing systemic inflammation, the lipid transporting ability of HDL in JIA patients is not impaired.
- © 2012 by American Heart Association, Inc.