PPAR  as a new therapeutic target in inflammatory bowel diseases

[...]specific natural or synthetic ligands of PPAR[GAMMA] can induce a mean 2-3-fold expression of this receptor in a positive feedback loop. 27 Secondly, different studies have demonstrated in vitro a synergistic effect of insulin and corticosteroids in inducing in vitro human PPAR[GAMMA] expression by cultured adipocytes. 25, 28 The NFκB and stress kinase pathways seem to be essential in post translational modifications of this nuclear receptor, but their regulatory effects on PPAR[GAMMA] expression remain uncertain. Other studies also indicate a role of PPAR[GAMMA] in tumour suppression, particularly in colon cancer. 6- 8 Therefore, greater knowledge of PPAR[GAMMA] expression and function in intestinal homeostasis and during inflammation will fuel speculations about its potential therapeutic effects in IBD to prevent inflammation and colorectal cancer. 81 The discovery that 5-ASA is a new topical ligand for this receptor expressed by colonic epithelial cells paves the way for the development of new molecules specifically targeting intestinal PPAR[GAMMA]. Because 5-ASA was originally developed without any prior knowledge of its molecular target, there is hope that the research described above will lead to rationale optimisation or development of better PPAR[GAMMA] ligands.