Interleukin-13 inhibits nitric oxide production in human colonic mucosa
Kolios, G.; Wright, K.L.; Linehan, J.D.; Robertson, D.A.; Westwick, J.
Hepato-Gastroenterology 47(33): 714-717
2000
ISSN/ISBN: 0172-6390 PMID: 10919016 Document Number: 519188
Background/Aims: Nitric oxide synthesis is increased in rectal biopsies from patients with ulcerative colitis and colonic epithelial cells are considered to be a major source of nitric oxide in intestinal inflammation. Methodology: Human colonic biopsies from normal bowel mucosa and colonic epithelial cell line HT-29 were cultured in the presence of the inflammatory cytokines IL-1alpha+TNF-alpha+IFN-alpha added after 1 hour pretreatment with vehicle or Interleukin-13. Nitrite levels were determined at 30 hours in culture supernatants by a fluorometric assay. Results: Unstimulated human colonic biopsies and HT-29 cells produced a basal amount of nitrite. Stimulation with IL-1alpha+TNF-alpha+IFN-alpha induced a significant (P<0.001) increase of nitrite generation by both human colonic biopsies and HT-29 cells. The presence of Interleukin-13 produced a significant (P<0.001) suppression of the cytokine-induced nitrite generation from both colonic biopsies and HT-29 cells. Conclusions: Nitric oxide generation in human colonic mucosa is susceptible to manipulation by proinflammatory cytokines. Interleukin-13 has an inhibitory effect on cytokine induced nitrite production in colonic mucosa and could play an anti-inflammatory role in intestinal inflammation.