The glycosaminoglycans (GAG)
Glycosaminoglycans are long chains of sugars present in the connective tissues, spread in almost all organs and tissues that make up our body, particularly concentrated in the cartilage, joints and extracellular matrix. The functions of GAG are many and with different specificities, depending on their location: protection, recognition, support, nutrition and hydration, thanks to the function of recovery and union with water molecules.
In the urinary tract, the most superficial portion of the urothelium is protected by GAG, among the main ones:
• Hyaluronic acid
• Heparan sulphate
• Keratin sulfate
• Chondroitin/dermatan sulfate
These substances, which are often linked to the superficial proteins of the urothelial cells, constitute the urothelial barrier, to form a sort of "filter" that protects foreign molecules (bacteria, uric acid crystals, toxic substances) contained in the urine. So, the altered production of glycosaminoglycans can predispose to recurrent bacterial infections, cause severe pain or bladder burning, urination urgency and frequency, symptoms characteristic of some urothelial diseases among which, interstitial cystitis.