Glomerulations have been considered a good diagnostic marker for interstitial cystitis/bladder pain syndrome (IC/BPS). We systematically characterized gene expression, inflammation and neovascularization in patients with IC/BPS with and without glomerulations to investigate biological significance of glomerulations in IC/BPS.
We sequenced total RNA obtained from bladder mucosal biopsies of 21 patients with IC/BPS without Hunner lesions, including with (11) and without (10) glomerulations, and 9 controls of normal bladder. Differentially expressed genes (DEGs) were searched to identify significantly enriched genes and biological processes for each group. Digital quantitative analysis of CD3-, CD20-, CD138-, human mast cell tryptase-, and vascular endothelial growth factor (VEGF)-positive cells, and CD31-positive microvessels was performed to assess subepithelial inflammation, neovascularization, and microvasculature.
Patients with glomerulations showed a similar gene expression profile to those without glomerulations, or to controls (Fig. 1). No differences in biological pathways or densities of lymphoplasmacytic and mast cells, VEGF-positive cells, and microvessels were detected between patients with IC/BPS and controls, regardless of the presence/absence of glomerulations (Fig. 2).
This study demonstrated that there are no significant differences in gene expression, inflammation, and neovascularization between patients with and without glomerulations. These results may support the growing clinical evidences that casted a doubt on the role of glomerulations in IC/BPS.