Effect of Infliximab and Adalimumab on Experimental Colitis Following Orally Supplemented Iron

Background: Orally administered iron can induce colonic inflammation in healthy animals and aggravate experimental colitis. Aim: To investigate the influence of the biologic agents infliximab and adalimumab on the severity of TNBS colitis following orally supplemented iron. Materials-Methods: 204 Wistar rats were allocated into 14 groups. Colitis was induced by TNBS. Iron was administered via a mouth catheter at a dose of 0.027, 0.3, and 3%/kg diet per day, respectively. Infliximab was subcutaneously administered on the 2nd and 6th day in a dose of 5mg/kgBW, while adalimumab was administered on the 2nd day in a dose of 2mg/kgBW. On the 8th day, all animals were euthanatized. Activity of colitis and extent of tissue damage were assessed histologically. Tissue Tumor Necrosis Factor- (t-TNF-) and malondialdehyde (t-MDA) were estimated. Results: In normal rats both agents significantly worsen the degree of inflammation induced by moderate or high iron supplementation despite the disappearance of t-TNF-, and reduction of t-MDA. In the groups of TNBS colitis and moderate or high iron administration, both agents again significantly worsen the degree of inflammation despite the significant reduction in the t-TNF- and t-MDA. Conclusion: Adalimumab and infliximab do not ameliorate the inflammation in TNBS-induced colitis aggravated by orally administered iron. These findings might be clinically relevant in patients with active IBD under concurrent treatment with biologic agents and per oral iron.