Increased urinary 8-hydroxy-2'-deoxyguanosine excretion after ileal neobladder replacement

To examine whether orthotopic neobladder replacement using either ileum or colon segments results in increased oxidative stress, by measuring urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), one of the most commonly used markers for evaluating oxidative DNA damage.

Urinary levels of 8-OHdG and creatinine, urine analysis, nutritional status, and acid-base and electrolyte balances, were assessed in 22 patients with an ileal neobladder, 28 with a colon neobladder, 37 with an ileal conduit and 22 healthy volunteers. The results from both types of orthotopic neobladder, the ileal conduit and in the healthy controls were compared.

The mean (sd) ratios of urinary 8-OHdG to urinary creatinine in patients with an ileal neobladder, colon neobladder, ileal conduit and in controls were 20.4 (7.8), 15.2 (4.3), 15.9 (5.1) and 15.2 (5.4) ng/mg, respectively. The urinary 8-OHdG ratio in the first group was significantly higher than in the other three groups. Among patients with a neobladder, the urinary 8-OHdG ratio was closely associated with the degree of pyuria, but not age, gender, the interval from surgery, body weight, height, serum creatinine or the degree of metabolic acidosis.

These findings suggest that creating an ileal neobladder caused significantly greater oxidative stress than a colon neobladder, ileal conduit, or that in healthy controls. Therefore, it is recommended to conduct a careful long-term follow-up considering the possible development of malignant disease after urinary diversion, especially by an ileal neobladder.