Anales RANF

P.94 URINARY ATP CONCENTRATION IS RELATED TO DETRUSOR PRESSURE DURING VOIDING M. Silva-Ramos 1,2,3 , A. Lopes 3 , D. Silva 1,2 , I. Silva 1,2 & Paulo Correia-de-Sá 1,2 1 Laboratório de Farmacologia e Neurobiologia, 2 Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, and 3 Serviço Urologia, Centro Hospitalar do Porto (CHP), Porto, Portugal. The bladder urothelium releases huge amounts of ATP into the bladder lumen in response to mechanical stress, both stretch and increase in the local pressure (Ferguson et al., 1997, J Physiol 505: 503-11). The urinary ATP concentration is directly correlated to the voided volume, suggesting that urothelium stretch impacts on urinary ATP levels (Silva-Ramos et al., 2013, PLoS One 8:e64696). Here, we investigated if bladder internal pressure during voiding also influences urinary ATP concentrations. Male patients scheduled for urodynamic investigation of LUTS, were recruited. Patients were asked to void at normal desire to an uroflowmetry apparatus. Then, the bladder was catheterized with a 7Fr double lumen catheter and the urine residual volume measured. Next, standard filling cistometry and pressure-flow studies were performed. Urine samples collected during the uroflowmetry were snap frozen in liquid nitrogen and preserved at −80°C until ATP determination using the luciferin -luciferase method. A total of 50 patients were included in the study. The patients’ average age was 59.8 [27-80] years old and the mean urinary ATP concentration was 2.95 [0.45-12.53] nM. Correlation between urinary ATP and Pdet@Qmax was independent of the voided volume (p<0,001). The urinary ATP content was not different among patients with and without detrusor overactivity: 3.05±0.37 and 2.87±0.62 nM, respectively. Data suggest that the voiding dynamics significantly affects urinary ATP concentrations. Higher detrusor pressures during voiding are correlated to higher urinary ATP concentrations, an effect that is independent of the voided volume. Detrusor overactivity had no impact on urinary ATP concentrations. Thus, both stretch and pressure induced urothelial ATP release impacting on urinary ATP concentrations. Urinary ATP may be a surrogate of detrusor pressure during voiding. Work supported by FCT (FEDER funding, project UID/BIM/4308/2016); IS was in receipt for a PhD Studentship from FCT (SFRH/BD/88855/2012). Correlation between urinary ATP (nM) Pearson´s r P Voided volume 0,238 0,096 Pdet@Qmax 0,689 <0,001 Bladder outlet obstruction index 0,640 <0,001 Bladder contractility index 0,561 <0,001