Relationships between cytokines and the amounts of microsymbionts in microecological disorders of the human intestine

Cytokines and chemokines, as well as gut microsymbionts, are sufficient participants in the intercellular communications, thus supporting homeostasis of gut mucosa. However, these components may be of key significance for intestinal inflammation and damage to epithelial barrier. This work expands the understanding of the relationships between intestinal microbial communities and the local cytokine network of the host. The paper presents the results of the correlation analysis between total microbial number of intestinal microsymbionts and the level of pro- (TNFα, IFNγ, IL-8) and anti-inflammatory cytokines (IL-10, IL- 1ra) in coprofiltrates obtained from clinically healthy people examined for gut dysbiosis. Determination of cytokines in coprofiltrates was carried out by ELISA technique (JSC Vector-Best, Russia). The study of 65 microsymbiocenoses of the human gut was carried out by classical bacteriological methods. Identification of obligate-anaerobic, facultative-anaerobic bacteria and fungi was carried out by time-of-flight mass spectrometry using MALDI TOF-MS Microflex LT series (Bruker Daltonians, Germany). These studies have revealed the leading role of associations between enterobacteria, fungi and representatives of the Staphylococcus genus in gut dysbiosis. In general composition of the obligate-anaerobic association, we have observed a change of consortia from several types of Bifidobacteria and Lactobacilli in eubiotic state to a monoid variant in dysbiosis. At the same time, the number of associations that included Clostridia was increased. The analysis of correlations between cytokine indices and the number of gut microbiota showed persistance of significant associations established during eubiosis under dysbiosis conditions, with an increase in their correlation coefficient: Bifidobacterium spp., Enterobacteriaceae, Staphylococcus spp., Candida spp. and TNFα. At the same time, in dysbiosis, the direction of the connections changed, and new correlations were determined: for Staphylococcus spp. and IFNγ; Staphylococcus spp. and IL-8; Enterobacteriaceae and IL-1ra, IFNγ. The established features of correlations between indices of microsymbiocenosis and quantitative changes in cytokines allow us to consider the number, composition of microsymbiocenosis and cytokine profile as factors that may affect the state of gut homeostasis in eu- and dysbiosis.