Novel Biomarkers for Diagnosis and Therapeutic Assessment of Overactive Bladder: Urinary Nerve Growth Factor and Detrusor Wall Thickness

Clinical diagnosis of overactive bladder (OAB) varies greatly and is based on subjective symptoms. A better way to diagnose and assess therapeutic outcome in patients who present with OAB needs to be developed. Evidence has shown that urinary proteins, such as nerve growth factor (NGF) and prostaglandin E2(PGE2) levels increase in patients with OAB, bladder outlet obstruction (BOO) and detrusor overactivity (DO). Urinary NGF level increases physiologically in normal subjects at urge to void, but increases pathologically in OAB patients at small bladder volume and at urgency sensation. Patients with OAB dry and OAB wet have significantly higher urinary NGF levels compared to controls and patients with increased bladder sensation. Urinary NGF levels decrease after antimuscarinic therapy and further decrease after detrusor botulinum toxin injections in refractory OAB. A higher urinary NGF level could be a biomarker for sensory nerve‐mediated DO. Urinary NGF levels could be a potential biomarker for diagnosis of OAB and serve for the assessment of the therapeutic effect of antimuscarinic therapy. Another potential biomarker for the diagnosis of OAB is detrusor wall thickness. It has been hypothesized that the bladder wall increases in thickness in patients with OAB. The thickened detrusor wall might decrease in response to antimuscarinic treatment, and measurement of detrusor wall thickness might be a useful biomarker for the evaluation of OAB. However, current investigations do not yet provide a uniform observation among various studies.