Combination therapy of pentoxifylline and TNFalpha monoclonal antibody in dextran sulphate-induced mouse colitis.

BACKGROUND

Tumour necrosis factor-alpha (TNFalpha) has been suspected of playing an important role in the pathogenesis of inflammatory bowel diseases, and has become a target for the treatment of these diseases. Open-label, placebo controlled studies have shown that engineered CDP571 and chimeric anti-TNF antibody (cA2) provide a significant benefit in Crohn's disease. Since these antibodies have to be used repeatedly to maintain remission in inflammatory bowel disease, there is a concern that their use may compromise host defence and produce toxic side-effects.

METHODS

We evaluated the combined use of mouse specific TNFalpha mab (25 microg/mouse, Endogen) and pentoxifylline (PF, 100 mg/kg/day, p.o., TNFalpha release inhibitor) in the DSS (3% dextran sulphate solution) model of mouse colitis. Colitis was induced by the feeding of 3% DSS for three cycles. The study groups were: Group I: single injection of rat anti-mouse IgG, Group II: single injection of TNFalpha mab, Group III: daily PF for three cycles, Group IV: single injection of TNFalpha mab + PF for three cycles, Group V: TNFalpha mab at the beginning of each cycle (three injections) and Group VI: TNFalpha mab (three injections) + daily PF for three cycles. Daily disease activity (DAI) was measured throughout the study. At the end of each cycle, colon tissue was processed for histology, myeloperoxidase (MPO) and plasma TNFalpha.

RESULTS

Mice treated with a single injection of TNFalpha alone or TNFalpha mab + PF showed significantly lower DAI, inflammation scores and ulcer index compared with the IgG treated group. Mice treated with TNFalpha mab + PF had no ulcers. Multiple injections of TNFalpha mab or TNFalpha mab + PF showed greater inhibition in DAI and cytokines in the first two cycles. However, in the third cycle, multiple injections of TNFalpha mab showed adverse proinflammatory effects.

CONCLUSION

The simultaneous administration of pentoxifylline and TNFalpha mab may enhance therapeutic outcomes in inflammatory bowel disease and reduce the side-effects associated with the repeated use of TNFalpha mab.