Urinary Neurotrophin Levels Increase in Women with Stress Urinary Incontinence after a Midurethral Sling Procedure

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.

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 LUTS and OAB wet patients (n=32) were used as controls. Urinary neurotrophin levels were measured by enzyme-linked immunosorbent assay and normalized to creatinine concentration.

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<0.05; BDNF: 1.99±0.71 vs. 2.71±0.45, p<0.05). After surgery, there was a significant increase of both neurotrophins (vs. baseline, p<0.05) 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 LUTS (p=0.019). A trend for a higher mean Qmax reduction in women with de novo urgency was also found (p=0.085).

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.

Urology. 2016 [Epub ahead of print]

Tiago Antunes-Lopes, Ana Coelho, Rui Pinto, Sérgio C Barros, Célia D Cruz, Francisco Cruz, Carlos M Silva

Department of Urology, Hospital de S. João, Porto, Portugal; Faculty of Medicine, University of Porto, Portugal; I3S - Instituto de Inovação e Investigação em Saúde, IBMC - Institute for Molecular and Cell Biology, University of Porto, Portugal. Electronic address: ., Department of Experimental Biology, Faculty of Medicine, University of Porto, Portugal; I3S - Instituto de Inovação e Investigação em Saúde, IBMC - Institute for Molecular and Cell Biology, University of Porto, Portugal., Department of Urology, Hospital de S. João, Porto, Portugal; Faculty of Medicine, University of Porto, Portugal; I3S - Instituto de Inovação e Investigação em Saúde, IBMC - Institute for Molecular and Cell Biology, University of Porto, Portugal.

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