Nerve growth factors sense OAB in children

By Sally Robertson, B.Sc.Jul 18 2012

Researchers may have found a reliable biomarker for diagnosing overactive bladder (OAB) in children and monitoring their treatment outcome.

Measuring urinary nerve growth factor (NGF) seems to be an effective alternative to the current method of diagnosis, which is based on a combination of symptom evaluation and measures of urine flow and volume.

"Many factors influence changes in detrusor overactivity, including environmental factors, mental status changes, variations in hydration, the nature of the disease process itself or other unrecognized factors," explain Tayfun Oktar (Istanbul University, Turkey) and colleagues.

A more objective method of both assessing OAB and monitoring treatment outcome is needed for the pediatric population, they say.

In adults, urinary NGF levels have been observed to be associated with OAB. However, until now, this association has not been tested in children, says the team.

As reported in the Journal of Pediatric Urology, the team found that pretreatment levels of NGF and NGF normalized to the concentration of urinary creatinine (NGF/Cr) were significantly higher in 40 children who had OAB than in a group of 20 children who did not have OAB.

The mean baseline NGF levels among the children with versus without OAB were 30.75 pg/mL versus 9.75 pg/mL and the corresponding mean baseline NGF/Cr levels were 0.53 versus 0.16.

Following 6 months of antimuscarinic treatment (oxybutynin 0.3‑0.5 mg/kg per day), continence was improved in all cases of OAB, with complete dryness in seven (17.6%) children and a greater than 90% decrease in incontinence in seven (7.6%) children. A partial response was observed in 26 (64.7%) children.

The team reports that the mean urinary NGF/Cr level among the patients with OAB was also significantly reduced, to almost as low as that of the control group.

The researchers say that NGF is believed to be involved in the physiology and pathophysiology of detrusor activity. "Studies have demonstrated that chronic administration of NGF to the bladder in rats leads to bladder hyperactivity and increases the firing frequency of dissociated bladder afferent neurons."

Such biomarkers may be a reasonable alternative for assessing OAB in the pediatric age group, they suggest.

Furthermore, it may be possible to determine specific cutoff values of urinary NGF levels and these could be used to tailor the maintenance of the antimuscarinic therapy individually, adds the team.

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