Background: ApoA-IV, an apolipoprotein (apo) with antioxidant, antiatherogenic, and antiinflammatory properties, was recently demonstrated to inhibit dextran sulfate sodium (DSS)-induced experimental colitis in mice. We therefore hypothesized that apoA-IV may be associated with disease activity in patients with inflammatory bowel disease (IBD).
Methods: We addressed this question by testing for associations between apoA-IV genotypes, apoA-IV plasma levels, inflammatory parameters, and clinical disease activity in 206 patients with Crohn's disease (CD), 95 subjects with ulcerative colitis (UC), and 157 healthy controls.
Results: In CD patients, apoA-IV plasma levels were inversely associated with C-reactive protein (CRP) (P = 0.005) and disease activity (P = 0.01) in univariate analysis. In multiple logistic regression analysis, apoA-IV levels were identified as an independent predictor of elevated CRP (odds ratio [OR] 0.956, 95% confidence interval [CI]: 0.916-0.998, P = 0.04) and active disease (OR 0.957, 95% CI: 0.918-0.998, P = 0.04). In UC patients the apoA-IV gene variant 360 His (P = 0.03) but not apoA-IV levels (P = 0.15) were associated with increased disease activity in univariate analysis. This association, however, was lost in multiple logistic regression analysis (OR 3.435, 95% CI 0.995-11.853, P = 0.05).
Conclusions: To our knowledge, this is the first study to demonstrate an association of apoA-IV with disease activity in patients with CD. Further studies are needed to define the relationship of apoA-IV to IBD.