[Discussion of the immunomorphological role of interactions between mast cells and Helicobacter pylori in the gastric mucosa].

Helicobacter pylori induced gastritis accounts for 70% of cases in the structure of this pathology. Features of the long-term inflammatory reaction of the mucous membrane are directly related to the mechanisms of bacterial pathogenicity, and features of immunogenesis within narrow limits of the specific tissue microenvironment of organ structures. Mast cells appear to be one of the key players (promoters) in the regulation of the inflammatory mediator cascade and the formation of cytokine-induced expression. Possessing a wide arsenal of biologically active substances, mast cells are able to participate in the formation of the immune response and resistance of the gastric mucosa, modulating both pro- and anti-inflammatory effects. The antigen-presenting features of mast cells are of interest in terms of interaction with H. pylori and induction of mucosa bacterial colonization. The aim of study was to assess the mast cell tryptase profile of the gastric mucosa in the immunopathogenesis of H. pylori-associated inflammation. Material and methods. The study included 19 biopsies of the gastric mucosa with unknown status of H. pylori infection. Microslides were stained with hematoxylin and eosin, and Giemsa's dye for plain microscopy. H. pylori infection of the gastric mucosa was detected using the immunohistochemical method. Using double immunofluorescent labeling, localization of tryptase-positive mast cells and H. pylori strains was detected. Results. In patients infected with H. pylori (n=12), there was a significant increase in the number of tryptase-positive mast cells (177.99±30.55 vs 88.58±11.49; p<0.05) with activation of secretory pathways and release of protease into the extracellular matrix of the gastric mucosa. The quantitative parameters of mast cells in the group of patients with an undetected pathogen and signs of a chronic inflammation of the gastric mucosa were statistically significantly lower than in the group of infected patients. Co-localization of tryptase-positive mast cells and H. pylori strains (with the formation of areas of large free-lying granule accumulation around the glands with pronounced degree of H. pylori contamination) was detected in gastrobiopsy specimens, the fact evidencing their close involvement in the development of inflammatory reactions of the gastric mucosa. Conclusion. The study demonstrated the features of mast cells and H. pylori interaction revealing previously unknown aspects of gastritis pathophysiology. The data obtained contribute a valuable insight to choose a treatment strategy for H. pylori-associated gastritis.

[Extracellular matrix collagen fiber structures of the gastrointestinal connective tissues in mice after a 30 day orbital flight].

The organs of the digestive system experience high sensitivity to the orbital flight factors and may limit the implementation of the professional activities of crews on International space station. The connective tissue as a system-forming matrix of the integrative and buffering metabolic environment has a particular importance in the space biomedicine because it provides the inner organ functionality in the conditions of changing level of the gravitational incentive. Aim - to study the adaptive mechanisms of the fibrous component of the extracellular matrix of the connective tissue of stomach and intestines on the effect of prolonged microgravity. MATERIAL AND METHODS: Using histochemical methods the condition of collagen fibers of a specific tissue microenvironment of the membranes of stomach and intestines of C57BL/6N mice (58 males with an initial body weight of 27.1±0.7 g) after a 30-day space flight and the following 7-day land readaptation was studied as well as in the animals representing corresponding control groups. RESULTS AND DISCUSSION: Laboratory animal presence on the biosatellite «BION-M¼ No. 1 has led to the fibrous reduction of extracellular matrix of connective tissue in the studied organs of digestive system structure except for the proper lamina of the gastric mucous membrane. Fibrillogenesis increase in the gastrointestinal tract in comparison with the indicators of space flight animal group has been found after 7 days of the biosatellite landing. The collagen fibers were not characterized by the significance change from the vivarium control group during the experiment with the land modelling of orbital flight conditions. CONCLUSION: The obtained results represent the evidence of fibrous structure gravity sensitivity of extracellular matrix of the connective tissue and show the relevance in the sphere of preventive measure improvement of the digestive system organs in the profession of astronauts in the orbital flight conditions.