Can urinary nerve growth factor be a biomarker for overactive bladder?

The clinical diagnosis of overactive bladder (OAB) greatly varies and is based on subjective symptoms. A more objective method to diagnose and assess therapeutic outcome in OAB patients, especially for health care providers not trained in urology, needs to be found. Evidence has shown that urinary proteins such as nerve growth factor (NGF) and prostaglandin E(2) levels increase in patients with OAB, bladder outlet obstruction, and detrusor overactivity. Urinary NGF level increases physiologically in normal subjects at urge to void, but increases pathologically in OAB patients at a small bladder volume and with a sensation of urgency. Recent studies have shown that patients with OAB dry and OAB wet have significantly higher urinary NGF levels compared with control groups and patients with increased bladder sensation. Urinary NGF levels decrease after antimuscarinic therapy and further decrease after detrusor botulinum toxin injections in refractory OAB. Urinary NGF level could be a potential biomarker for diagnosis of OAB and assessment of the therapeutic effect of antimuscarinic therapy. The latest medical advances in this field are reviewed herein.