P241 Systemic redox status associates with disease activity and clinical phenotypes in Inflammatory Bowel Disease

Abstract Background Oxidative stress is a key pathophysiological mechanism in inflammatory bowel diseases (IBD). Systemic levels of oxidative stress are reflected by reduced levels of free thiols (FT) in circulating proteins, especially those in albumin, which associates with disease activity in IBD. Yet, clinal value of circulating FT level as biomarkers of disease and therapy response remains largely unexplored. Here we investigated the association between plasma FT levels and clinical parameters, the plasma inflammatory proteome and medication use. Methods Plasma samples from 1,028 patients with IBD (567 Crohn's disease [CD] and 461 ulcerative colitis [UC]), and 500 healthy controls (HCs) participating in the 1000IBD and LifeLines projects were profiled for free thiols (FT), uric acid, bilirubin and 92 inflammation-related proteins (Olink Inflammation panelÒ). All biomarkers were associated with clinical phenotypes using general linear models adjusting for age, sex, body mass index, smoking and medication use. Results Plasma FT levels were significantly lower in IBD compared to HCs (p