Purpose: Glomerulation has been one of the requisite criteria for the diagnosis of interstitial cystitis (IC) but the mechanisms for glomerulation remain unclear. Therefore, we investigated the relationship between the cystoscopic findings of vascular events and the expression of angiogenic growth factors in IC bladders to identify the possible mechanisms inducing glomerulations in IC.

Materials and methods: In 45 patients suspected of having IC continuous, fixed point cystoscopic observation was performed during hydrodistention using spinal anesthesia. Bladder biopsies were performed in these cases and in an additional 5 asymptomatic cases. Thereafter, the expression of platelet derived endothelial cell growth factor/thymidine phosphorylase (PDECGF/TP) was measured by enzyme-linked immunosorbent assay. Immunohistochemical staining for PDECGF/TP and vascular endothelial growth factor was also performed.

Results: Of 45 symptomatic patients 38 had glomerulations during cystoscopic examination. In these patients during hydrodistention the blood flow in bladder wall vessels was interrupted by whitish fibrous bundles. Thereafter petechial bleeding began from capillaries distal to obstructed vessels during bladder emptying. PDECGF/TP expression in patients with glomerulation was significantly higher than in symptomatic patients without glomerulation or asymptomatic patients (p < 0.001). In patients with glomerulations a high positive rate for PDECGF/TP (97.4%) and vascular endothelial growth factor (68.4%) staining was observed, while no positive staining was found in asymptomatic patients.

Conclusions: Glomerulations during hydrodistention are highly associated with the over expression of angiogenic growth factors in the bladder. Thus, it seems likely that neovascularization promoted by angiogenic growth factors has an important role in the pathogenesis of IC, inducing glomerulations during hydrodistension.