Ileocecal Valve Removal Reverses the Constipating Effects of Loperamide in Rats

Background: Previous evidence associating ileocecal valve removal (ICVR) with a reduced risk of fecal impaction of the ileocecum in cystic fibrosis indicated possible benefits from ileocecal valve loss in disorders with inhibited proximal colon transit caused by fecal dehydration and hypoperistalsis. We aimed to investigate the ability of ICVR in reversing fecal impaction in a loperamide-induced model of a similar pattern of inhibited proximal colon transit in rats.

Materials and methods: Thirty pubertal Sprague-Dawley rats were rendered constipated with subcutaneous loperamide treatment (1 mg/kg/d) for 7 d. On day four, rats were allocated to groups: ICVR (n = 12), total colectomy (TC, n = 9), and sham operation (SO, n = 9). Fecal pellet number and consistency were assessed daily. On day seven, all rats were gavaged with barium. Two hours later, intestinal transit ratio (distance of barium head from the pylorus adjusted for small intestine length) and adjusted (for total intestine length) barium-to-anus distance were assessed.

Results: ICVR showed higher transit ratio and shorter barium-to-anus distance, that is, faster transit, than SO (P < 0.0001); differences between ICVR and TC were not significant (P > 0.06). Furthermore, ICVR and TC showed similar reduction in hard feces, compared with SO (P < 0.0001). TC showed higher diarrhea rate than ICVR (P < 0.0001).

Conclusions: ICVR led to an effective, similar to TC, reversal of the constipating effects of loperamide and, unlike TC, was not associated with diarrhea. Our findings support the idea that ICVR might be beneficial in disorders with inhibited proximal colon transit resulting from fecal dehydration and hypoperistalsis, such as refractory cystic fibrosis-related intestinal obstruction. Potential clinical implications merit further study.

Keywords: Cystic fibrosis; Distal intestinal obstruction syndrome; Ileocecal valve removal; Intestinal transit; Loperamide-induced constipation.