Urinary cytokines in women with refractory detrusor overactivity: A longitudinal study of rotating antibiotic versus placebo treatment

Over 50% of women with detrusor overactivity (DO), who do not respond to therapy have been shown to have bacteriuria, which may stimulate the release of inflammatory cytokines than can enhance nerve signalling, leading to symptoms of urgency. This study made use of a consecutive series of urine samples collected from women with refractory DO, who participated in a clinical trial of rotating antibiotic therapy. The aim was to determine the effect of bacteriuria and antibiotic treatment on the levels of urinary cytokines, and to correlate the cytokine concentration with patient outcome measures relating to urgency or urge incontinence. The urinary cytokines chosen were IL-1α, IL-1 receptor antagonist, IL-4, IL-6, IL-8, IL-10, CXCL10 (IP-10), MCP-1 and TNF-α. The presence of bacteriuria stimulated a significant increase in the concentrations of IL-1α (P 0.0216), IL-1 receptor antagonist (P 0.0264), IL-6 (P 0.0003), IL-8 (P 0.0043) and CXCL-10 (P 0.009). Antibiotic treatment significantly attenuated the release of IL-1α (P 0.005), IL-6 (P 0.0027), IL-8 (P 0.0001), IL-10 (P 0.049), and CXCL-10 (P 0.042), i.e. the response to the presence of bacteria was less in the antibiotic treated patients. Across the 26 weeks of the trial, antibiotic treatment reduced the concentration of five of the nine cytokines measured (IL-1α, IL-6, IL-8, IL-10 and CXCL-10); this did not reach significance at every time point. In antibiotic treated patients, the urinary concentration of CXCL-10 correlated positively with four of the six measures of urgency. This study has shown that cytokines associated with activation of the innate immune system (e.g. cytokines chemotactic for or activators of macrophages and neutrophils) are reduced by antibiotic therapy in women with refractory DO. Antibiotic therapy is also associated with symptom improvement in these women, therefore the inflammatory response may have a role in the aetiology of refractory DO.