The impact of decreasing urinary IgA levels on decreased bacteriuria in a rat model of ileal augmented bladder.

PURPOSE: Bacteriuria is frequently observed in patients with urinary tract reconstruction using intestinal segments. These patients have higher urinary IgA levels than those with a normal bladder. We examined the relationship between bacterial adherence and urinary IgA in a rat ileal augmented bladder model.

MATERIALS AND

METHODS

Rat ileal augmented bladder models were divided into groups 3 months and 1 year after surgery. Experimental cystitis was induced in the 2 groups by transurethral inoculation of Escherichia coli. At 14 days after inoculation the rats were sacrificed, and cfu/mg tissue of the bladder and ileal patch was measured. Rats with negative urine culture in the 2 groups were sacrificed, and urine specimens and augmented bladder tissue were collected. Urinary IgA levels were determined and immunohistochemistry staining of the tissue was done with anti-rat IgA antibody.

RESULTS

In rats with experimental cystitis E. coli significantly adhered to the bladder and ileal patch in the 3-month group but not in the 1-year group. Urinary IgA levels in the 3-month group were significantly higher than in the 1-year group. On immunohistochemistry the number of IgA immunoreactive cells in the ileal patch decreased in the 1-year group compared to that in the 3-month group.

CONCLUSIONS

These results suggest that increased urinary IgA may be the cause of the higher incidence of bacteriuria in patients with urinary reconstruction using intestinal segments. Therefore, the decrease in IgA production in the inserted intestinal segments may contribute to a spontaneous decrease in of bacteriuria with time.