Urinary Neurotrophin Levels Increase in Women With Stress Urinary Incontinence After a Midurethral Sling Procedure

OBJECTIVE To investigate the association between urinary neurotrophin levels, maximum flow rate (Qmax) variation, and the appearance of urgency in women with stress urinary incontinence (SUI) after a midurethral sling (MUS) procedure. MATERIALS AND METHODS Thirty-one women with SUI were treated with a MUS. One year later, the outcome of surgery and the onset of urgency were assessed. At baseline and 1-year follow-up, urine was collected to measure nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) concentration, and Qmax variation was calculated. Urine samples from healthy women (n = 20) without lower urinary tract symptoms and overactive bladder (OAB) wet patients (n = 32) were used as controls. Urinary neurotrophin levels were measured by enzyme-linked immunosorbent assay and normalized to creatinine concentration. RESULTS At baseline, urinary levels of NGF and BDNF were similar between SUI and healthy women (NGF: 2.10 +/- 0.68 vs 1.99 +/- 1.05; BDNF: 1.99 +/- 0.71 vs 1.81 +/- 0.90), and significantly inferior to OAB wet patients (NGF: 2.10 +/- 0.68 vs 2.50 +/- 0.54, P <.05; BDNF: 1.99 +/- 0.71 vs 2.71 +/- 0.45, P <.05). After surgery, there was a significant increase of both neurotrophins (vs baseline, P <.05) to the values of OAB wet patients. Moreover, there was a significantly higher percentage increase of NGF in women with de novo urgency than in those without lower urinary tract symptoms (P =.019). A trend for a higher mean Qmax reduction in women with de novo urgency was also found (P =.085). CONCLUSION These findings suggest that increased bladder outlet resistance after a MUS may play a key role in the rise of urinary neurotrophins, promoting sensitization of bladder primary afferents and causing de novo urgency in susceptible patients. (C) 2016 Elsevier Inc.