An investigation of the nature of bladder mucosal glycoconjugates and their role in interstitial cystitis.
The long-term objective of this study is to elucidate the role of bladder mucosal glycosaminoglycans and mucin glycoproteins in the development of interstitial cystitis and other bladder diseases. Bladder biopsies and urine samples from patients and healthy controls were analyzed for glycoconjugates by biochemical and immunochemical methods. Due to the limited availability of human bladders for research purposes, detailed analysis of rabbit bladders glycoconjugates were also carried out. Biochemical analysis of rabbit bladders indicate that while the major portion of the glycoconjugates in the urothelium is sialoglycoprotein, low levels of heparan sulfate and chondroitin sulfate are also present. The correlating immunohistochemical data show very weak staining of the rabbit bladder epithelium by antiglycosaminoglycan antibodies. In contrast, the lamina propria and muscle layers stained intensely for chondroitin sulfate and hyaluronic acid. Thus, the quantity of glycosaminoglycans associated with the bladder epithelial layer, particularly as extracellular matrix components on the luminal surface of the bladder, appears insignificant. On the other hand, several lectins and anti-epitectin (a MUC1 sialoglycoprotein) antibodies showed strong staining of the luminal surface of rabbit and normal human bladders. Further, preliminary results with anti-epitectin antibodies reveal a weaker and patchy staining of biopsy specimens from interstitial cystitis patients compared to controls. The urinary levels of glycosaminoglycans and epitectin, in interstitial cystitis patients and healthy controls were determined by chemical or immunoassays. Urinary epitectin, but not glycosaminoglycans, was decreased in interstitial cystitis patients.