The aim is to assess the levels of certain cytokines IL-6, TNF-α, IL-1β и IL-10, and BDNF in the blood plasma of the elderly, depending on degree of cognitive impairment. 65 elderly with (vascular dementia) or without cognitive impairment were enrolled in the study. The level of cytokines and BDNF were measured in plasma by ELISA. It was found that, regardless of the degree of cognitive impairment, the condition of systemic chronic low-grade inflammation is characteristic of the elderly. Against this background, plasma levels of BDNF were increased in elderly with vascular dementia, reaching statistical significance compared with healthy individuals. Such changes in the level of BDNF may reflect a compensatory repair mechanism in neurodegeneration or be associated with a defective axonal transport or utilization of BDNF in the central nervous system paralleled by increased serum concentrations.

The study of the small intestine microbiota in humans is difficult due to the low availability of biomaterial. Non-invasive methods of metabolomics and bioinformatic data analysis can expand our understanding of the structure and role the small intestine microbiota in maintaining homeostasis of the body. The article presents the trajectory of age-related changes in the microbial community of the small intestine in healthy individuals in the context of interaction with the cytokine and neuroendocrine systems within the metaorganism, using the methods of gas chromatography - mass spectrometry of microbial markers (GCMS MM) and optimal scaling. 110 practically healthy individuals: children, adults and elderly, were included into the study. The number of the main types of small intestine microbiota (Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, and Fusobacteria) was determined in peripheral blood by the GCMS MM method. To construct the trajectories of changes in the small intestine microbiota and indicators of the cytokine and neuroendocrine systems with age, the optimal scaling technique based on the multivariate Gifi transformation (CATPCA method) was used. It was found, that the bacterial community of the small intestine of both children and the elderly and seniors has a significantly low total number of microorganisms, due to the low content of bacteria of the types Firmicutes and Actinobacteria against the background of a high number of representatives of the types Proteobacteria and Fusobacteria, in comparison with similar indicators in adults. Assessment of the trajectory of age-associated changes in the microbiota of the small intestine showed: 1) children have strong dynamic fluctuations in the number and connections within the community of microorganisms against the background of the formation of connections between the main regulatory systems of the metaorganism – immune and neuroendocrine; 2) adults present the plasticity and consistency of the functioning of the immune and nervous systems, what determine the state of dynamic balance of the small intestine microbiota; 3) healthy aging characterize by hight degree of cooperation between the main members of the bacterial community, which ensures the stability of the system at a new level, as one of the mechanisms of adaptation of the organism. Thus, the using the methods of GCMS MM and optimal scaling, allows us to expand our understanding of the age-associated trajectory of changes in the small intestine microbiota and its cooperation with the immune and neuroendocrine systems within the metaorganism, which can be used in the development of new methods of therapy of an infectious and non-infectious diseases.