Ileocystoplasty in rats: metabolic, renal and enteropatch changes in a mid- and long-term follow-up

INTRODUCTION: Bladder augmentation predisposes humans to many metabolic, renal and enteropatch changes. Our aim was to evaluate in a rat model of ileocystoplasty mid- and long-term urinary, metabolic, renal and graft changes. MATERIALS AND METHODS: We performed an ileocystoplasty and a sham operation in 30 rats. Seven augmented rats and 3 sham-operated animals were euthanized after 1, 3 and 6 months. We performed urinalysis, urine culture and blood sampling for serum electrolytes and urea. Histopathological changes of the ileal patch and kidneys were also evaluated. RESULTS: The urine cultures were positive in 14.3, 57 and 71%, respectively, 1, 3 and 6 months after surgery. Urinary pH, serum chloride and urea of the augmented group were significantly higher. Bladder calculi were formed in 23.8% of ileocystoplasty. Histopathological examination showed urothelialization of the graft with hyperplastic/metaplastic changes. The kidneys showed glomerular depletion and a marked distal tubular ectasia. CONCLUSIONS: Our data showed that, in a mid- and long-term follow-up, rat bladders subjected to ileocystoplasty displayed hyperchloremic metabolic acidosis, electrolyte imbalance, enhanced serum blood urea levels and glomerular/tubular changes. Hyperplastic and/or metaplastic changes at the junctional zone were observed. Our experimental results suggest that frequent monitoring of renal function and surveillance of humans who have undergone ileocystoplasty are recommended.