Abstract: PD12-06
Sources of Funding: 2017 Urology Care Foundation Residency Research Award sponsored by the Russell Scott, Jr, MD Research Fund; Intramural Funds provided by the Division of Urology, Department of Surgery of the Duke University School of Medicine

Introduction

The NLRP3 inflammasome has gained recognition for its role in mediating inflammation through its activation of pro-inflammatory cytokines like IL-1β. It has been implicated in diabetic sequelae such as nephropathy, retinopathy, neuropathy, and vasculopathy, and in sterile cystopathy such as hemorrhagic cystitis and bladder outlet obstruction. We hypothesize that the NLRP3 inflammasome is activated in the inflammatory response in diabetic bladder dysfunction (DBD), the most common of all diabetic complications.

Methods

Ins2 (Akita) diabetic mice and age-matched controls underwent 4hr voiding assays to determine development of early DBD, defined as increased frequency and smaller voided volumes. Inflammation and fibrosis were compared through bladder weights, Evans Blue assay, Masson&[prime]s trichrome stain, and H&E stain. Active caspase-1, a functional moiety of activated inflammasome, was targeted intracellularly by a fluorescent caspase inhibitor and measured through flow cytometry. Paired geometric mean fluorescence intensity was compared via paired T-test, and all other univariate analysis was performed with ANOVA. Significance was defined as p<.05.

Results

Diabetic mice demonstrated DBD as early as week 11 with increased frequency of voids (p<.01), increased total voided volume (p<.05), and decreased volume per void (p<.05), compared to wild type mice. Inflammasome activation was evident as witnessed by increased active caspase-1 in diabetic mice (Figure 1). Diabetic mice also had increased Evans blue extravasation, indicating increased capillary permeability, an early sign of inflammation. Furthermore, diabetic bladders demonstrated hypertrophy compared to wild type bladders (20.6 vs 18.9mg; p=0.2); however, there was no increase in collagen deposition or histological changes on H&E staining.

Conclusions

Inflammasomes are activated early in the development of diabetic bladder dysfunction and may contribute to the onset of voiding dysfunction.

Funding

2017 Urology Care Foundation Residency Research Award sponsored by the Russell Scott, Jr, MD Research Fund; Intramural Funds provided by the Division of Urology, Department of Surgery of the Duke University School of Medicine