Urinary Biomarkers in Women with Refractory Urgency Urinary Incontinence Randomized to Sacral Neuromodulation versus OnabotulinumtoxinA Compared to Controls.

PURPOSE: We measured urinary biomarker levels in women with refractory urgency urinary incontinence and controls at baseline and 6 months after treatment with sacral neuromodulation or intradetrusor injection of onabotulinumtoxinA. We also assessed the association of baseline biomarkers with posttreatment urgency urinary incontinence episodes and overactive bladder symptom bother outcomes. MATERIALS AND METHODS: First morning urine samples were collected from consented trial participants and age matched women without urgency urinary incontinence. Biomarkers reflecting general inflammation, neuroinflammation, afferent neurotransmitters and tissue remodeling were measured using standardized enzyme-linked immunosorbent assay and activity assays as appropriate. Symptom bother was assessed by the overactive bladder questionnaire and urgency urinary incontinence episodes were determined by bladder diary. Linear models were used to examine differences in mean biomarker levels and the change in urgency urinary incontinence episodes and symptom bother between baseline and 6 months. Modest evidence of a potential association was represented by p ≤0.01 and p ≤0.004 represented moderate evidence of an association with outcomes. RESULTS: Baseline biomarker levels differed little between cases and controls except tropoelastin (p = 0.001) and N-terminal telopeptide collagen type 1 (p <0.001). Changes in biomarker levels 6 months after intervention included decreases in collagenase (p <0.001) in both treatment groups and increases in interleukin-8 (p = 0.002) and matrix metalloprotease-9 (p <0.001) in the onabotulinumtoxinA group. Higher baseline calcitonin gene-related peptide across both treatments (p = 0.007) and nerve growth factor in the onabotulinumtoxinA arm (p = 0.007) were associated with less reduction in overactive bladder symptom bother. CONCLUSIONS: Refractory urgency urinary incontinence is a complex condition. These data suggest that matrix remodeling and neuropeptide mediation may be involved in its pathophysiological mechanisms and response to treatment.

Sacral nerve stimulation reduces elevated urinary nerve growth factor levels in women with symptomatic detrusor overactivity.

OBJECTIVES: To investigate changes in urinary nerve growth factor (uNGF) in women with symptomatic detrusor overactivity (DO) following peripheral nerve evaluation (PNE) for sacral neuromodulation vs controls. STUDY DESIGN: There were 23 subjects with overactive bladder symptoms and DO who failed management with anticholinergics and 22 controls consented to participate in this prospective pilot study. Urine specimens were collected from controls at baseline for evaluation of uNGF and creatinine. Subjects were evaluated at baseline and 5 days after a trial of sacral nerve stimulation referred to as a PNE. Each visit included urine collection for uNGF and, Incontinence Quality of Life Questionnaire, Urinary Distress Inventory Questionnaire, postvoid residual volume, and a 3-day voiding diary. uNGF levels were measured by enzyme-linked immunosorbent assay and expressed as uNGF pg/creatinine mg. RESULTS: Subjects with DO had significantly higher baseline uNGF levels (corrected for creatinine) compared with controls (19.82 pg/mg vs 7.88 pg/mg, P < .002). Seventeen DO subjects underwent PNE and were evaluated at the end of the testing period. There was a significant improvement in quality of life scores for subjects after PNE compared with baseline (Urinary Distress Inventory Questionnaire: 7.0 vs 13.7, P < .001; Incontinence Quality of Life Questionnaire: 87.3 vs 52.8, P < .0001). Concordantly, uNGF levels significantly decreased from 17.23 pg/mg to 9.24 pg/mg (P < .02) after PNE. CONCLUSION: uNGF levels decrease with symptomatic response in DO subjects undergoing PNE. DO subjects had significantly higher uNGF at baseline vs controls, and uNGF levels significantly decreased after only 5 days of sacral nerve stimulation. These findings support a larger study to validate the use of uNGF as an objective tool to assess therapeutic outcome in patients undergoing PNE for sacral neuromodulation.