Increased nerve growth factor levels in the urinary bladder of women with idiopathic sensory urgency and interstitial cystitis

Objectives To determine whether nerve growth factor (NGF) is elevated in painful conditions of the urinary bladder (idiopathic sensory urgency, interstitial cystitis and painful chronic cystitis). Patients and methods Sixteen women patients were recruited from the Urodynamic Clinic at The Elizabeth Garrett Anderson Hospital, London. Four each had idiopathic sensory urgency (mean age 34 years, range 24-51), chronic cystitis (mean age 51 years, range 40-79) and interstitial cystitis (mean age 41 years, range 29-53). Four women who had genuine stress incontinence on cystometry but with no irritative symptoms were used as controls (mean age 45 years, range 35-54). The levels of NGF were determined in bladder biopsies from all women and biopsy sections were immunostained to detect NGF. Results The levels of NGF were higher in samples from all three painful bladder conditions than in samples from controls. Immunostaining showed increased NGF expression in the urothelium, most marked in patients with idiopathic sensory urgency. Conclusions The increased level of NGF may explain several clinical and pathological features in these conditions, including sensitization of nociceptor fibres and increased numbers of mast cells. We propose that anti-NGF treatment may be a rational and effective treatment in intractable bladder pain.