Scientific and Research Department of Plastic and Reconstructive Oncourology,
SI “National Cancer Institute” Ministry of Health of Ukraine, Kyiv
It has been proved that the GAG-layer simultaneously performs several important functions: it protects the deeper layers of the urinary bladder walls from irritants’ penetration from the urine; prevents giving rise and increase of inflammation, as well as reduces the degree of pain caused by inflammation [1, 21].
Urothelium defects are the cause of many chronic diseases of the urinary tract (interstitial cystitis, recurrent bacterial cystitis, radiation cystitis, overactive urinary bladder, etc.), accompanied by the appearance of such symptoms as urgent and frequent urination, urinary incontinence, pain during urination, syndrome of urinary bladder chronic pain. Such patients are largely limited in their daily activities and suffer from reduced quality of their life [2, 3].
The mechanism of pain in the bladder:
1. Damage of GAG-layer.
2. The destruction of the epithelial layer by aggressive structures.
3. Inflammation in sub-epithelial structures.
4. Activation of C-fibres and release of Neuropeptides.
5. Neurogenic inflammation.
6. Progression of fibrosis, scarring, shrinkage of the urinary bladder.
Chronic inflammation of the urinary bladder can lead to the replacement of its muscular wall by fibrous tissue, as well as sclerosis and ultimately to the development of microcysts . To solve this problem, the therapy designed to restore the protective layer of urothelium is recommended.
Today in clinical practice different treatment strategies are used. They suggest prescription of antidepressants, antihistamines, cysteine, leukotrienes receptors antagonists, internal bladder instillation of dimethyl sulfoxide to patient, but when the pain syndrome is present, opioid analgesics are prescribed. In difficult cases surgery can be performed (augmentation of urinary bladder, cystectomy with application of urine derivation methods), which is the only method of solving this problem [13-15].
In recent years the application of therapy that helps to restore the GAG-layer is actively studied.
The most studied among glycosaminoglycans are hyaluronic acid, chondroitin sulfates, dermatan sulfates, keratan sulfates and heparan sulfates that compose skin, tendons, cartilage, joints, providing mechanical strength and elasticity of inner organs, as well as elasticity of their joining .
In particular, hyaluronic acid is a glycosaminoglycan which, according to its chemical nature, is a branched chain of repeated disaccharide components (Fig. 1). At pH 7.0 level carboxyl groups of hyaluronic acid are fully ionized, bearing a negative charge and interacting with water molecules to form jelly-like matrix .
The name “Hyaluronic acid” was first suggested in 1934 by K. Meyer and J. W. Palmer, who identified this substance of the vitreous body of the eye. Its name comes from the Greek word hyalos – “glassy” and “uronic acid” .
It has been proved that glucosamine, chondroitin and hyaluronic acid have anti-inflammatory and analgesic effects, as well as water-containing biopolymer with silver ions has antibacterial effect, and the hyaluronic acid has derma-protective effect.