The effects of chronic cystitis on vesicoureteral reflux in an animal model

The purpose of this study was to determine if chronic cystitis interferes with maturation of the ureterovesical junction, thus prolonging vesicoureteral reflux in infant rhesus monkeys (Macaca mulatta). Serial implantations of a Proteus-infested silastic pellet into the bladder wall ensured continued infection as demonstrated by urine culture. Chronic cystitis as evidenced by pathological findings at surgery and sacrifice was created in a group of infant monkeys who had initial spontaneous vesicoureteral reflux. There was no evidence of pyelonephritis. Four animals represent a short term study since they were followed from four months to one year of age. Three animals were long term studies and were evaluated for at least 2 1/2 years. In no animals did chronic cystitis delay the normal disappearance of vesicoureteral reflux that is commonly seen in these animals as the ureterovesical junction matures, as demonstrated by serial cystograms. In two animals reflux (after initial clearing) reappeared when a bladder calculus formed in these chronically infected animals. Renal damage occured only in these animals. In conclusion, this animal model failed to demonstrate interference with normal vesicoureteral junction maturation in the face of a chronic bladder infection.