The influence of uremia and immunosuppression on an animal model for ischemic colitis.

Up to 1 percent of renal transplant recipients have been reported to develop ischemic colitis. Immunosuppressive agents and uremia have been implicated in the development of this complication, but their exact relationship remains unclear. A rat model was developed to determine the effects of uremia alone and in combination with immunosuppression on the development of ischemic colitis. Seventy-six animals were included in the study. Uremia and ischemic colitis were induced surgically. The immunosuppressive agents azathioprine and methylprednisolone were administered for 72 hours after a colonic segment was devascularized in chronically uremic rats. One-way analysis of variance (ANOVA) showed that uremia potentiates colonic ischemia significantly (4.09 cm2 vs 1.25 cm2, P less than 0.03). The addition of parenteral steroids (methylprednisolone) or azathioprine alone and in combination did not potentiate or reduce this ischemic process in uremic animals. Each of these factors alone is commonly present in the renal transplant population and can contribute to the development of potentially fatal ischemic colitis.