Urine nerve growth factor (NGF) level, bladder nerve staining and symptom/problem scores in patients with interstitial cystitis

BACKGROUND: Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a challenging disease, affecting thousands of people all around the world, especially women. Although there have been numerous theories regarding IC/BPS etiology, the physiopathology of the disease still remains unclear and there is a lack of certain treatment. OBJECTIVES: The aim of the study was to assess the role of nerve fibers and nerve growth factor (NGF) in the etiopathogenesis of IC/BPS symptoms by demonstrating if there is a correlation between urine NGF levels, amount of peripheral nerves in bladder mucosa and symptom severity. MATERIAL AND METHODS: A prospective clinical study was conducted with 15 IC/BPS patients and 18 controls. Urine NGF levels were measured by enzyme-linked immunosorbent assay (ELISA). Bladder punch biopsies were obtained from 15 IC/BPS patients and 9 controls. Immunohistochemistry was performed for S-100 to highlight peripheral nerve twigs in bladder mucosa. The O'Leary-Sant Interstitial Cystitis Symptom and Problem Index (OSICSPI) was used to assess symptom severity and effects of the disease on the patients' life. RESULTS: NGF normalized to urine creatinine (NGF/Cr) levels in IC/BPS patients were significantly higher than in controls, 0.34 ±0.22 and 0.09 ±0.08 pg/mL: mg/dL, respectively (p < 0.001). The mean symptom score in IC patients was 12.27 ±2.4 (median: 12) and the mean problem score was 10.9 ±2.3 (median: 12). The mean mucosal nerve (S-100 stained) area in the IC/BPS group was significantly higher than in the controls, 2.53 ±1.90 vs 1.0 ±0.70, respectively (p = 0.018). In correlation analyses, the NGF/Cr level in IC/BPS patients was found significantly correlated with the O'Leary-Sant IC Symptom and Problem Index scores independently (p = 0.001 and p = 0.028, respectively). CONCLUSIONS: NGF seems to be a promising biomarker in IC/BPS. It may help clinicians in diagnoses and patient follow-up. Thus, unnecessary, expensive and invasive tests, interventions and treatments might be avoided.