MODERN VIEWS ON ROLE OF VITAMIN D IN PATHOGENESIS OF BRONCHIAL ASTHMA IN CHILDREN

Bronchial asthma (BA) is a common disease of airways in children characterized by chronic inflammation, as well as respiratory symptoms varying in time and intensity. In recent years, an increase in the prevalence of BA has been seen, both among the adult and children's population. The current trend stimulates scientists to continue studying the probable influence of various factors on this process, including the role of micronutrient deficiency, especially antioxidants, methylene donors and vitamin D (VD). Hypovitaminosis D has been considered as a provoking factor affecting the pathogenesis of various pathological processes. The results of numerous studies confirm the opinion that VD affects the intensity of inflammation, reducing the production of pro-inflammatory cytokines and secretion of mucus, and stimulates the secretion of the anti-inflammatory cytokine IL-10. VD-regulated genes encode the synthesis of antimicrobial peptides that provide protection against bacteria and viruses provoking BA exacerbations. The article discusses the role of tissue growth factor (TGF-β) as an initiator of fibrosis in the epithelial cells of the respiratory tract through the activation of epithelial mesenchymal transition signals, and also discusses the inhibitory effect of VD on the processes of airway remodeling in BA. Today it is known that VD can inhibit the progression of pulmonary fibrosis in various ways, including suppression of the expression of TGF, inhibition of the motility of epithelial cells induced by TGF-β, reduction of the excessive activation of RAS (antifibrotic effect), increase in the level of TGF antagonist. Separately, the issue of the possible strengthening of the antioxidant defense of the body in BA is considered through optimization of the supply of the organism with VD. Conclusion. Thus, taking into account the fact that to date, the results of clinical studies of the use of VD in the treatment of BA gave conflicting results, additional studies are needed to address controversial issues regarding the role of VD deficiency in the pathogenesis of BA and its control. Further understanding of the mechanisms underlying the airway remodeling will help develop a set of measures aimed at minimizing the risk of structural changes in AD.