Abstract
Bladder epithelium is not only a simple defence against infections, but it is also a specialized tissue regulating complex bladder functions and playing an active role in the pathogenesis of many bladder diseases. There is strong evidence that different chronic inflammatory bladder diseases, such as recurrent urinary tract infection (UTI), chemical or radiation cystitis and painful bladder syndrome/interstitial cystitis (PBS/IC), can be pathophysiologically linked in the first step of the disease to the loss of the glycosaminoglycan (GAG) mucous layer independently of the original cause of the inflammatory process. The aim of this article is to review the current evidence on the clinic applications of GAGs in urology, with particular emphasis on the therapeutic use of hyaluronic acid (HA) and chondroitin sulphate (CS). A comprehensive electronic literature search was conducted in May 2011 using the Medline database. Three studies supported the decrease of the rate of recurrent UTIs by restoring the GAG layer, showing a significant reduction of UTI rates and a prolonged median time to recurrence after HA intravesical instillations in women with recurrent UTI. We provide higher level evidence by reporting a prospective, randomized, double-blind, placebo-controlled study on the use of intravesical HA and CS in women with recurrent UTIs. A significant reduction of 77% in the UTI rate per patient per year versus placebo was observed at the end of the study. Nine studies were published between 2002 and 2011 on the use of HA and CS to treat PBS/IC. Three of them evaluated the use of GAGs bladder instillation to prolong the effects of bladder hydrodistension. In the other six studies the efficacy of HA bladder instillations to reduce symptoms score was assessed. Preliminary studies support data on the role of HA-CS in detrusor overactivity, nonbacterial cystitis and urological malignancies. Few data are available regarding the mode of action of HA-CS or its effectiveness in the management of bladder diseases. The major issue in interpreting the available evidence regarding HA-CS is that most of the reported studies are nonrandomized and without a control arm. HA-CS may be considered for further studies, including randomized, controlled trials with adequate power.