Инфекция и иммунитет (Dec 2024)
Relationship between <I>E. coli, Enterobacter</i> spp. and <i>S. aureus</i> isolated from intestinal microflora and blood proteins associated with the immune system and infectious diseases during 3-day dry immersion
Abstract
“Dry” immersion is one of the methods for simulating some factors of a space flight. Volunteer-derived intestinal microbiota previously studied by “dry” immersion showed profoundly deteriorated state of microflora and blood protein composition. The study was aimed to analyze mechanisms underlying a positive correlation with amount of intestinal E. coli, and negative correlation between S. aureus and Enterobacter spp. with the number of human blood proteins assessed by proteomics methods based on mass spectrometry, in a 3-day experiment “dry” female immersion. 6 female volunteers aged from 25 to 40 years took part in the 3-days “dry” immersion experiment. During the experiment, the subjects did not take any drugs that could affect the microflora. Fecal samples were collected once per 1–2 days before the onset of the experiment and once on days 1–3 after the end of the “dry” immersion, number of microorganisms in the above-mentioned samples was assessed. Capillary blood samples were obtained by puncture of the terminal phalanx of the ring finger 2 days before the onset of the experiment, on day 1, 2 and 3 during dry immersion and 2 days afterwards. The relationship between the level of proteins in the samples and the number of intestinal microorganisms was described using a regression model in which the blood specific protein was a dependent variable, and the number of microorganisms was an independent variable. The STATISTICA 12.0 program was used for data processing. When analyzing the data obtained, 30 proteins were identified, which positively correlated with the amount of E. coli and negatively correlated with the amount of S. aureus and Enterobacter spp. While considering the events in which these proteins are involved in the human body, they were divided into several groups. In the current study, there were examined 6 proteins associated with infectious diseases (PSMA2, PSMC3, PSME2, NCKAP1, LTF, ENO1) and 10 immune-related proteins (the above-mentioned proteins, as well as CCT2, APOB, FGB, CA1, STOM). Thus, it is necessary to continue close examination of the mechanisms underlying this relationship in the interest of ensuring spaceflight medical safety.
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