Neurotrophins and Proneurotrophins as Biomarkers for Overactive Bladder Syndrome in Aging Females.

Background/Objectives: Overactive bladder (OAB), common in elderly women, involves urgency, frequency, and nocturia, with complex phenotypes. The use of neurotrophins as non-invasive urinary biomarkers has been previously explored. The objective of this study was to assess the diagnostic and therapeutic utility of urinary biomarkers in a Canadian population of aging female OAB patients. Methods: We conducted a single-center prospective study of aging female patients diagnosed with OAB and age-matched healthy controls, where we conducted pre- and post-treatment assessments using a combination of clinical questionnaires, voiding diaries, and urinary biomarkers nerve growth factor (NGF), proform of NGF (proNGF), brain-derived neurotrophic factor (BDNF), proform of BDNF (proBDNF), and neurotrophin receptor p75 extracellular domain (p75^ECD)) quantified using ELISA. Baseline and post-treatment urinary biomarker levels in OAB patients were compared with those of controls. Results: OAB patients and controls at baseline displayed significant differences in neurotrophin levels and in their ratios of mature/precursors. In the post-treatment OAB cohort, only NGF and proNGF exhibited significant improvement correlating with clinical symptom relief. Biomarkers in non-responders remained unchanged, suggesting heterogeneity in therapeutic response. Conclusions: Urinary neurotrophins show promise as non-invasive diagnostic markers of OAB and monitoring treatment response in aging female patients. While this study focused on patients broadly diagnosed with OAB, future research should aim to classify OAB subtypes-such as those based on urodynamic studies or underlying pathophysiology-to better understand how urinary neurotrophins can differentiate between mechanisms like detrusor overactivity, detrusor underactivity, or bladder outlet obstruction. This will enhance their relevance in guiding personalized treatment strategies and predicting outcomes.