Electron microscopic investigation of the bladder urothelium and glycocalyx in patients with interstitial cystitis

The electron microscopic appearance of the bladder urothelium and glycocalyx was investigated in ten patients with well defined interstitial cystitis and compared to the findings in ten control patients with stress incontinence as the only symptom. Ruthenium red, a polycationic dye which binds specifically to cell surface acid polysaccharides, was used to demonstrate the glycocalyx. In cases of interstitial cystitis two types of luminal cell were observed, each possessing a distinct surface glycocalyx. One type of cell possessed numerous plaques of asymmetric unit membrane associated with a relatively thin glycocalyx. The second type of cell was characterised by numerous microvilli and a relatively thick glycocalyx. In control material each type of cell and its associated glycocalyx was identified with similar frequency. Our study concludes that there are no differences in the morphologic appearances of the glycocalyx and of urothelial cells in patients with interstitial cystitis when compared with controls. Hence, the hypothesis that an important pathogenic factor in interstitial cystitis is a defective glycocalyx associated with a permeable urothelium, has not been supported.