Effect of drugs on crystal adhesion to injured urothelium.

The normal urothelium is covered by a glycosaminoglycan (GAG) layer which acts as a barrier to the adhesion of crystals. Destruction of the GAG layer increases the number of adhered crystals, and it is therefore assumed that it promotes crystal growth and stone formation. Intravesical instillation of pentosanpolysulfate, an exogenous glycosaminoglycan, after destruction of this layer reduces the adhesion of crystals to the urothelium. Intramuscular administration of carbenoxolone sodium following the experimental destruction of the GAG layer increases the rate of healing of the layer and reduces the number of adhered crystals.