Correlation of urinary nerve growth factor level with pathogenesis of overactive bladder

The origin of overactive bladder (OAB), which is a leading cause of lower urinary tract symptoms, remains unknown. Nerve growth factor (NGF) is one of the neurotrophic factors which are needed for the maintenance of sensory neurons. It is known that too much expression of NGF may induce bladder hyperactivity. In this study, we explored the correlation of the level of urinary NGF with various pathogenic OAB such as idiopathic, neurogenic OAB, and bladder outlet obstruction (BOO).

The study group included 51 OAB patients. Thirteen patients (7 females and 6 males) had idiopathic detrusor overactivity (DO) without BOO, 6 female idiopathic OAB without DO (sensory urgency), 16 patients with BOO due to BPH, and 16 patients with neurogenic DO (10 due to spinal cord injury (SCI), 6 due to cerebrovascular disease (CVD)). Thirty-two patients who had normal cystometric findings (23 females and 9 males) without OAB symptoms were used as controls. Urinary NGF levels were measured by enzyme-linked immunosorbent assay technique (ELISA) and the results were normalized based on creatinine (Cr) concentration.

The urinary NGF levels in patients with neurogenic DO due to SCI, BOO, and sensory urgency were significantly higher compared with those of normal cystometric finding patients. However, the levels of urinary NGF were not statistically significant between patients with idiopathic DO without BOO, neurogenic DO due to CVD and patients with normal cystometric findings.

These data suggest that urinary NGF levels could serve as a basis for adjunct diagnosis of OAB.