Urinary nerve growth factor correlates with the severity of urgency and pain

Introduction and hypothesis

Urinary nerve-growth-factor (NGF) level reflected the severity of urgency in patients with lower urinary tract symptoms (LUTS) and pain in patients with Bladder pain syndrome/interstitial cystitis (BPS/IC). The aim of this study was to investigate the levels of biomarkers, nerve growth factor (NGF), and prostaglandin E2 (PGE₂) among disease groups sharing similar urinary symptoms and to elucidate which symptoms are related to individual biomarker levels.

Methods

We studied 83 patients with LUTS who visited our outpatient clinic from May 2011 to December 2012. On the basis of clinical symptoms and a 3-day voiding diary, patients were classified into three groups: those with frequency (n?=?13), overactive bladder (OAB) (n?=?35), and BPS/IC (n?=?35). Patients with stress urinary incontinence (SUI) or microscopic hematuria served as controls (n?=?24). Storage symptoms were evaluated based on OAB symptom score (OAB-SS).

Results

Mean patient age was 62.08?±?11.47 (range, 23–84). Urinary NGF and creatinine-normalized NGF levels were significantly increased in those with OAB (201.90 and 4.08, respectively) and BPS/IC (173.71 and 2.72) compared with controls (77.77 and 1.29) and those with frequency (67.76 and 1.23). Neither value significantly differed between OAB and BPS/IC patients or between controls and frequency patients. Urinary PGE₂ and creatinine-normalized PGE₂ levels were not significantly different among groups. On linear regression analysis, urinary NGF levels were significantly correlated with urgency severity overall (R?=?0.222) and also pain in BPS/IC patients (R?=?0.409).

Conclusions

The levels of urinary NGF were elevated in patients with OAB and BPS/IC but not those with frequency and reflected the severity of urgency. In BPS/IC patients, urinary NGF increased with pain severity.