Omega-3 Fatty Acids Exacerbate DSS-Induced Colitis Through Decreased Adiponectin in Colonic Subepithelial Myofibroblasts

Background: Although the immunoregulatory effects of omega-3 fatty acid and adiponectin have been postulated, their role ill intestinal inflammation is controversial. The aim of this study was to determine whether dietary fat intake influence activity of colonic inflammation through modulating this system. Methods: C57BL/6 mice received dextran Sulfate sulfate for induction of colitis. Mice were fed a control diet. omega-3 fat-rich diet, omega-6 fat-rich diet, or Saturated fat-rich diet. Some mice were administered at peroxisome proliferator activated receptor-gamma; agonist, pioglitazone. Messenger RNA expression of adiponectin and its receptors were analyzed. Adiponectin expression in colonic mucosa of ulcerative colitis patients was also analyzed. Results: The receptors for adiponectin were found to be ubiquitously expressed in epithelial cells. intraepithelial lymphocytes, lamina proprial mononuclear cells, and subepithelial myofibro-blasts from colonic tissue. but adiponectin was only expressed ill myofibroblasts. Induction of colitis significantly decreased the expression of adiponectin ill colonic mucosa. The omega-3 fat diet group, but Clot the other fat diet groups. Showed exacerbated colitis with a farther decrease of adiponectin expression. Pioglitazone treatment ameliorated the level of decrease in adiponectin expression and improved colonic inflammation induced by the omega-3 fat-rich diet. Ill patients with ulcerative colitis, the expression level of adiponectin ill colonic mucosa was also decreased compared with that ill control mucosa. Conclusions: Adiponectin was found to be expressed in myofibroblasts. Adiponectin expression was significantly Suppressed by induction of colitis, and aggravation of colitis after exposure to omega-3 fat may be due to a further decrease ill the expression level of adiponectin. (Inflamm Bowel Dis 2008; 14.-1348-1357)