Ureteroneocystostomy contributes to late functional and morphological changes in rat kidney transplants

Purpose: We investigated whether the surgical technique used to reconstruct the ureter has an impact on the late function of kidney transplants by com paring ureteroneocystostomy and ureteroureterostomy. To rule out alloantige neic mediated effects on late graft dysfunction kidney transplants were per formed in a syngeneic model. Materials and Methods: Rat kidney isografts were transplanted with simultan eous ureteroneocystostomy or ureteroureterostomy. Unilaterally nephrectomiz ed rats sen ed as controls. Eight weeks after transplantation intrapelvic p ressure was measured during baseline diuresis, and after intravesical and i ntrapelvic infusion. Albuminuria was determined monthly until sacrifice at week 52. Histomorphological analysis included the degree of glomerulopathy, tubular atrophy, interstitial fibrosis and intimal hyperplasia, CD4(+)- an d CD8(+) T cells, and macrophages were identified using immunohistochemical testing. Results: Eight weeks after transplantation intrapelvic pressure during base line diuresis and after intrapelvic infusion was significantly increased in rats with ureteroneocystostomy versus those with ureterostomy and unilater al nephrectomy, whereas intravesical infusion did not change the pressure i n any group. During followup albuminuria after ureteroureterostomy did not differ from that after unilateral nephrectomy. In contrast, albuminuria sig nificantly increased after ureteroneocystostomy from week 36 onward. At wee k 52 the uteter and kidney after ureteroureterostomy and unilateral nephrec tomy had a normal appearance, whereas all ureters were dilated after ureter oneocystostomy. Nevertheless, 6 of the 3 kidneys in the ureteroneocystostom y group had a normal appearance. However, histomorphological findings in ra ts with transplants and ureterovesical anastomosis demonstrated significant ly more interstitial fibrosis, CD8(+) T cells and macrophages than isograft s ureteroureterostomy. Conclusions: As a surgical technique for restoring the urinary tract after kidney transplantation, ureteroneocystostomy contributes to the development , of long-term functional and histological renal changes. Partial obstructi on mag be the cause of this renal impairment.