Chronic bladder ischemia and oxidative stress: new pharmacotherapeutic targets for lower urinary tract symptoms

Chronic bladder ischemia is potentially a common cause of lower urinary tract symptoms in the elderly. Epidemiological studies have shown a close association between lower urinary tract symptoms and vascular risk factors for atherosclerosis, and investigations using transrectal color Doppler ultrasonography have shown a negative correlation between decreased lower urinary tract perfusion and International Prostate Symptom Score in elderly patients with lower urinary tract symptoms. Bladder blood flow is also known to decrease in men with bladder outlet obstruction as a result of benign prostatic hyperplasia. Studies in animal models suggest that chronic bladder ischemia and repeated ischemia/reperfusion during a micturition cycle might produce oxidative stress, leading to denervation of the bladder and the expression of tissue-damaging molecules in the bladder wall, which could be responsible for the development of bladder hyperactivity progressing to bladder underactivity. The effects of drugs with different mechanisms of action; for example, α1-adrenoceptor antagonists, phosphodiesterase type 5 inhibitors, free radical scavengers and β3-adrenoceptor agonist, have been studied in animal models of chronic bladder ischemia. The drugs, representing different treatment principles for increasing blood flow and decreasing oxidative stress, showed protective effects not only on urodynamic parameters, but also on negative effects on muscle contractility and on detrimental structural bladder wall changes. Improvement of lower urinary tract perfusion and control of oxidative stress can be considered new therapeutic strategies for treatment of bladder dysfunction induced by chronic ischemia.