One common etiologic theory of interstitial cystitis is a defect in the glycosaminoglycan component of the mucin layer that covers and protects the urothelium.

While the exact cause of interstitial cystitis is not known, it is probably related to many factors, including autoimmune, allergic and infectious etiologies.

According to one widely held theory, the symptoms of interstitial cystitis originate from a defect in the glycosaminoglycan component of the mucin layer that covers and protects the bladder urothelium8 (Figure 1). A deficiency of this layer is thought to cause interstitial cystitis. Low rates of urinary glycosaminoglycan excretion have been found in patients with interstitial cystitis. The glycosaminoglycan hypothesis is the basis for treating interstitial cystitis with glycosaminoglycan "replacements," such as sodium pentosan polysulfate (an exogenous, oral glycosaminoglycan) and heparin or hyaluronic acid administered intravesically.8,9 Irritating substances in the urine may leak through the urothelium, causing inflammation, tissue irritation and injury, mast cell degranulation and sensory nerve depolarization, which result in the urinary urgency, frequency and pain of interstitial cystitis.5,6,10 Glycosaminoglycans are highly hydrophilic and protective. They maintain a stable layer of water between the urothelium and the bladder lumen, and prevent adhesion to and invasion of the urothelium by bacteria, microcrystals, ions, proteins and other substances in the urine.

Copyright © 2008, Faye Combs