Insights from advances in research of chemically induced experimental models of human inflammatory bowel disease

Inflammatory bowel disease(IBD),the most important being Crohn's disease and ulcerative colitis,results from chronic dysregulation of the mucosal immune system in the gastrointestinal tract.Although the pathogenesis of IBD remains unclear,it is widely accepted that genetic,environmental,and immunological factors are involved.Recent studies suggest that intestinal epithelial defenses are important to prevent inflammation by protecting against microbial pathogens and oxidative stresses.To investigate the etiology of IBD,animal models of experimental colitis have been developed and are frequently used to evaluate new anti-inflammatory treatments for IBD.Several models of experimental colitis that demonstrate various pathophysiological aspects of the human disease have been described.In this manuscript,we review the characteristic features of IBD through a discussion of the various chemically induced experimental models of colitis(e.g.dextran sodium sulfate-,2,4,6-trinitrobenzene sulfonic acid-,oxazolone-,acetic acid-,and indomethacin-induced models).We also summarize some regulatory and pathogenic factors demonstrated by these models that can,hopefully,be exploited to develop future therapeutic strategies against IBD.

Bowel preparation for colonoscopy using standard vs reduced doses of sodium phosphate: A single-blind randomized controlled study

AIM: To evaluate the efficacy of a colonoscopy prepa-ration that utilizes a reduced dose of sodium phosphate(NaP) and an adjunct.METHODS: Sixty-two patients requiring screening colonoscopies were studied. Each patient was randomly allocated to receive either 50 NaP tablets(50 g) or 30 NaP tablets(30 g) with 10 mL of 0.75% sodium pico-sulfate for bowel preparation. NaP was administered at a rate of five tablets(5 g) or three tablets(3 g) every 15 min with 200 mL of water, beginning five to six hours before colonoscopy. The sodium picosulfate was administered with 200 mL of water on the night before the procedure. Both groups were compared in term of the efficacies of colonic cleansing, the time required for completion of the bowel preparation, and acceptability of the preparation.RESULTS: Sixty patients(n = 30 for each group) were analyzed. The cleansing efficacy tended to be higher in the 30 g NaP plus sodium picosulfate group as as-sessed by the mean total Ottawa scale score(50 g NaP6.70 ± 1. 42 vs 30 g NaP plus sodium picosulfate 6.17 ± 1.18 P = 0.072). The mean time for bowel prepara-tion tended to be shorter in the 30 g NaP plus sodium picosulfate group(50 g NaP 189.9 ± 64.0 min vs 30 g NaP plus sodium picosulfate 161.8 ± 57.6 min, P = 0.065). There were no significant differences between the two groups in the acceptability of the preparations(50 g NaP 83.3% vs 30 g NaP plus sodium picosulfate 86.7%, P = 0.500). There were no adverse events re-lated to bowel preparation in either of the groups.CONCLUSION: The colonoscopy preparation that uti-lized 30 g NaP with sodium picosulfate was comparable to that utilizing 50 g NaP. This novel bowel preparation might be useful before colonoscopy.