Correlation of blood proteome parameters to the number of certain intestinal microflora bacteria in healthy women

Introduction . Human intestinal microflora fulfils a wide range of important functions for the body. It provides non-specific anti-inflammatory defense through the production of bacteriocins, organic acids and substances with bacteriostatic properties. It also stimulates eukaryotic cells to synthesize mucin and substances with antimicrobial activity, thus suppressing the development of inflammatory reactions in intestinal epithelial cells. These bacteria obviously act synergistically with immunocompetent intestinal cells undergoing changes in zero gravity conditions modeled using dry immersion. Regulatory and metabolic changes which occur during model experiments are reflected, inter alia, in the protein composition of the blood. Objective . Identification of the relationship between the blood protein level and the amount of E. coli, Lactobacillus spp ., Enterococcus spp. and Bifidobacterium spp. in the intestine using an experimental model of 3-day dry immersion for potential use as clinical recommendations for the correction of intestinal microflora, based on data from the proteomic profile of the blood. Materials and methods . The study was conducted among six women aged 25–40 years. During 3-day dry immersion, the subjects were completely immersed in an immersion bath containing water at room temperature. Direct contact between the subjects’ skin and the water was excluded. During the study, fecal samples and capillary blood samples were taken from each of the participants. In order to assess the protein levels, chromatography-mass spectrometric analysis of samples of dried blood spots was performed using nano-HPLC Dionex Ultimate3000 combined with a timsTOF Pro mass spectrometer. The study of the number of intestinal bacteria was carried out using culture seeding of pre-diluted fecal samples on selective media according to a standard technique, followed by consideration of colonies. Results . The regression model showed a relationship between the levels of individual proteins and representatives of the intestinal microflora. A statistically significant correlation was found between blood proteins ENO1 ( r = 0.71), MYH9 and SPTA1 ( r = –0.99) with the amount of E. coli ; blood proteins EPB41, VCP, C8B, CCT2 ( r = 0.74), FAH, YWHAE ( r = –0.46) with the amount of Bifidobacterium spp . There was also a significant strong positive correlation between Lactobacillus spp. and proteins ENO1, CA2 (r =0.74) and S100A6 and HSPA4 ( r =–0.87). The CALM2 protein ( r = –0.76) correlated with the amount of Enterococcus spp.