Objective: To investigate the expression of urinary brainderived neurotrophic factor (BDNF) in benign prostatic hyperplasia patients with overactive bladder (OAB) symptoms and its correlation with the severity of OAB symptoms.
Methods: According to the inclusion and exclusion criteria, a total of 178 patients with benign prostatic hyperplasia who were to undergo transurethral resection of prostate (TURP) were enrolled in this study. All the patients had accepted basic preoperative evaluations, as well as an assessment of their International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS). The patients who had been scheduled for surgery had to take the urodynamic assessment. Urinary BDNF levels were measured by the enzyme-linked immunosorbent assay (ELISA) and the results were further normalized to the concentration of urinary creatinine (BDNF/Cr, mg/mol).
Results: The urinary BDNF/Cr levels of the patients with moderate and severe lower urinary tract symptoms were (1.189 ± 0.753) mg/mol and (1.817 ± 1.110) mg/mol (P < 0.001). The urinary BDNF/Cr levels of the patients with grades III-VI obstruction were (1.382 ± 0.945) mg/mol, (1.435 ± 0.938) mg/mol, (1.640 ± 1.104) mg/mol, and (1.653 ± 1.019) mg/mol, respectively (P > 0.05). There was no correlation between the urinary BDNF/Cr levels and the severity of obstruction (r = 0.103, P = 0.173). The urinary BDNF/Cr levels in the patients with and without OAB symptoms were (1.913 ± 0.843) mg/mol and (0.297 ± 0.183) mg/mol (P < 0.001). The urinary BDNF/Cr levels in the patients with mild, moderate and severe OAB symptoms were (1.501 ± 0.543) mg/mol, (1.806 ± 0.703) mg/mol and (2.560 ± 0.979) mg/mol, respectively (P < 0.05). There was a correlation between the urinary BDNF/Cr levels and the severity of OAB symptoms (r = 0.743, P < 0.001). The urinary BDNF/Cr levels in the patients with urodynamic detrusor overativity were significantly higher than those without detrusor overativity [(1.917 ± 0.866) mg/mol and (1.194 ± 1.013) mg/mol, P < 0.001].
Conclusion: There is no correlation between urinary BDNF and severity of obstruction in benign prostatic hyperplasia patients with moderate and severe lower urinary tract symptoms. The urinary BDNF levels in patients with OAB symptoms are elevated compared with patients without OAB symptoms, and are correlated with the severity of OAB symptoms.