Background: Intestinal fibrosis is mainly associated with Crohn's disease and is defined as a progressive and excessive deposition of extracellular matrix components. No specific antifibrotic therapies are available. In this study, we evaluate the antifibrotic effect of a novel 5-ASA analog able to activate the peroxisome proliferator-activated receptor γ, named GED-0507-34 Levo.
Methods: Colonic fibrosis was induced in 110 C57BL/6 mice by 3 cycles of 2.5% (wt/vol) dextran sulfate sodium administration for 6 weeks. The preventive effects of oral daily GED (30 mg · kg(-1) · d(-1)) administration were evaluated using a macroscopic and histological score and also through biological endpoints. Expression of main markers of myofibroblasts activation was determined in transforming growth factor (TGF-β)-stimulated intestinal fibroblasts and epithelial cells.
Results: GED improved macroscopic and microscopic intestinal lesions in dextran sulfate sodium-treated animals and reduced the profibrotic gene expression of Acta2, COL1a1, and Fn1 by 1.48-folds (P < 0.05), 1.93-folds (P < 0.005), and 1.03-fold (P < 0.05), respectively. It reduced protein levels of main markers of fibrosis (α-SMA and Collagen I-II) and the main TGF-β/Smad pathway components. GED also decreased the interleukin-13 and connective tissue growth factor expression by 1.89-folds (P < 0.05) and 2.2-folds (P < 0.005), respectively. GED inhibited TGF-β-induced activation of both fibroblast and intestinal epithelial cell lines, by regulating mRNA expression of α-SMA and fibronectin, and restoring the TGF-β-induced loss of intestinal epithelial cell markers. GED treatment also reduced the TGF-β and ACTA1 expression in primary human intestinal fibroblasts from ulcerative colitis patients.
Conclusions: GED ameliorates intestinal fibrosis in dextran sulfate sodium-induced chronic colitis in mice and regulates major profibrotic cellular and molecular mechanisms.