Rosiglitazone, a PPARgamma ligand, modulates signal transduction pathways during the development of acute TNBS-induced colitis in rats

A clinical trial of combined use of rosiglitazone and 5-aminosalicylate for ulcerative colitis

AIM: To investigate the therapeutic effects of the combined use of rosiglitazone and aminosalicylate on mild or moderately active ulcerative colitis (UC).

METHODS: According to the national guideline for diagnosis and treatment of inflammatory bowel disease (IBD) in China, patients with mild or moderately active UC in our hospital were selected from July to November, 2004. Patients with infectious colitis, amoebiasis, or cardiac, renal or hepatic failure and those who had received corticosteroid or immunosuppressant treatment within the last month were excluded. Following a quasi-randomization principle, patients were allocated alternatively into the treatment group (TG) with rosiglitazone 4 mg/d plus 5-ASA 2 g/d daily or the control group (CG) with 5-ASA 2 g/d alone, respectively, for 4 wk. Clinical changes were evaluated by Mayo scoring system and histological changes by Truelove-Richards’ grading system at initial and final point of treatment.

RESULTS: Forty-two patients completed the trial, 21 each in TG and CG. The Mayo scores in TG at initial and final points were 5.87 (range: 4.29-7.43) and 1.86 (range: 1.03-2.69) and those in CG were 6.05 (range: 4.97-7.13) and 2.57 (range: 1.92-3.22) respectively. The decrements of Mayo scores were 4.01 in TG and 3.48 in CG, with a remission rate of 71.4% in TG and 57.1% in CG, respectively. Along with the improvement of disease activity index (DAI), the histological grade improvement was more significant in TG than in CG (P < 0.05).

CONCLUSION: Combined treatment with rosiglitazone and 5-ASA achieved better therapeutic effect than 5-ASA alone without any side effects. Rosiglitazone can alleviate colonic inflammation which hopefully becomes a novel agent for UC treatment.

Pioglitazone, a PPARgamma ligand, suppresses NFkappaB activation through inhibition of IkappaB kinase activation in cerulein-treated AR42J cells

BACKGROUND AND AIM

NFkappaB plays a major role in the immune and inflammation responses of pancreatitis. Recently, there is increasing evidence that the expression and activity of PPARgamma may participate in the activity of NFkappaB. Therefore, we investigated a putative relationship of the two transcription factors in cerulein-treated pancreatic acinar AR42J cells.

METHOD

AR42J were stimulated by cerulein with or without the presence of a PPARgamma activator pioglitazone or a PPARgamma antagonist GW9662.

RESULTS

Treatment of AR42J cells with pioglitazone attenuated cerulein induced p50 and p65 NFkappaB dimer activity in the nucleus as measured by transcription factor assay. Cytosolic expression of IkappaBalpha protein was reduced by cerulein, basal signalling was not influenced by the PPARgamma inhibitor GW9662 and pioglitazone. Adversely, the inhibitory effect of pioglitazone on NFkappaB activity induced by cerulein was almost reversed by GW9662.

CONCLUSION

These findings provide evidence for the involvement of the nuclear hormone receptors PPARgamma in the activity of NFkappaB in cerulein-treated AR42J cells.