26th Annual EAU Congress: first prize Best Abstract in Non-Oncology category
Tuesday, 5 April 2011- A Portuguese group bagged the first prize for Best Abstract in Non-Oncology during the 26th Annual EAU Congress held recently in Vienna, Austria. Below is the winning abstract by T. Antunes-Lopes and colleagues, unedited and without additional commentary:
Title: Urinary levels of Brain Derived Neurotrophic Factor (BDNF) in women with overactive bladder (OAB) syndrome correlate with the severity of symptoms
Authors List: Antunes-Lopes, T.1, Pinto, R.1, Carvalho-Barros, S.2, Diniz, P.1, Martins-Silva, C.1, Duarte-Cruz, C.2, Cruz, F.1
1Hospital de São João and University of Porto, Urology and IBMC, Institute of Biology, Molecular and Cellular, Porto, Portugal, 2Faculty of Medicine, University of Porto, Institute of Histology and Embryology and IBMC-- Instituto de Biologia e Molecular e Cellular, Porto, Portugal
Introduction & Objectives
Nerve Growth Factor (NGF) may constitute a useful biomarker of OAB syndrome. Less is known about the role of BDNF, another ubiquitous neurotrophin, in lower urinary tract (LUT) function, both in normal and pathological conditions. However, BDNF was recently found in high concentrations in the urine of patients with bladder pain syndrome. In this study, we investigated urinary levels of BDNF in OAB patients and correlated them with the severity of symptoms. Additionally, we described urinary BDNF in a population of healthy volunteers to investigate physiological pattern of secretion and gender differences.
Material & Methods
Urine samples from 40 healthy volunteers (20 men and 20 women) were collected in the morning, afternoon and evening. The procedure was repeated 3 months later. Samples were adequately stored until further processing. Seventeen naive OAB female patients were enrolled in this study from the out-patient clinic consultation. Urine was also collected at baseline and 3 months. Urine samples were processed for ELISA analysis of urinary BDNF. The urine BDNF content was normalized against creatinine (Cr) concentration (BDNF/Cr ratio- pg/mg). For each OAB patient the severity of symptoms was accessed using Indevus Urgency Severity Scale (IUSS), at the time of urine collection, and correlated with the respective BDNF/Cr ratio.
In healthy volunteers, urinary BDNF levels were constantly very low, despite the time of urine collection (morning, afternoon and night). Moreover, no significant differences were found between male and female volunteers. In contrast, BDNF/Cr ratio was significantly higher in OAB patients compared to healthy female volunteers (morning urine sample) at baseline (980.3 ± 1774.8 vs 110.4 ± 159.5, p<0.01) and 3 months (399.5 ± 487.9 vs 131.1 ± 289.0, p<0.01). At baseline, there is a trend for patients with IUSS score of 4 (OAB wet) to have higher levels of urinary BDNF than those with 3 or less (1795.2 ± 2874 vs 535.8 ± 541). From baseline to 3 months evaluation, after non-pharmacological interventions, there was a decrease in urinary BDNF (980.3 ± 1774.8 vs 399.5 ± 487.9), accompanied by a reduction in IUSS score (3.29 ± 0.59 vs 3.18 ± 0.39) A significant correlation between BDNF/Cr ratio and IUSS score variations was found (r = 0.684, p<0.01).
To our knowledge, this is the first comprehensive study of urinary BDNF in healthy volunteers. In this group BDNF/Cr ratios were systematically low, irrespective of gender or time of urine sampling. In contrast, in OAB patients, urinary BDNF was very high and correlated with the severity of symptoms. The striking differences observed between OAB patients and controls clearly point that urinary BDNF may serve as a potential biomarker of OAB syndrome.