Abstract
BackgroundThe conditions of space flight have a significant effect on the physiological processes in the human body, yet the molecular mechanisms driving physiological changes remain unknown.MethodsBlood samples of 18 Russian cosmonauts who had conducted long-duration missions to the International Space Station were collected 30 days before launch and on the first and seventh days after landing.ResultsA panel of 125 proteins in the blood plasma was quantitated by a well-established and highly regarded targeted mass spectrometry approach. This method involves the monitoring of multiple reactions in conjunction with stable isotope-labeled standards at the University of Victoria - Genome BC Proteomics Centre.ConclusionsReduction of circulating plasma volume during space flight and activation of fluid retention at the final stage of the flight affect the changes in plasma protein concentrations present in the first days after landing. Using an ANOVA approach, it was revealed that only 1 protein (S100A9) reliably responded to space flight conditions. This protein plays an important role in the functioning of the endothelium and can serve as a marker for activation of inflammatory reactions. Concentrations of the proteins of complement, coagulation cascades, and acute phase reactants increase in the blood of cosmonauts as measured the first day after landing. Most of these proteins’ concentrations continue to increase by the 7th day after space flight. Similar dynamics are observed for proteases and their inhibitors. Thus, there is a shift in proteolytic blood systems, which is necessary for the restoration of muscle tissue and maintenance of oncotic homeostasis.
Highlights
The conditions of space flight have a significant effect on the physiological processes in the human body, yet the molecular mechanisms driving physiological changes remain unknown
Binding to Toll-like receptor 4 (TLR4) and advanced glycation end products (AGER) activates the MAP-kinase and NF-kappa-B signaling pathways resulting in the amplification of the proinflammatory cascade and IL-6 secretion
Analyzing the dynamics of 19 reliably different proteins, we found that most of these proteins are decreased on the first day after landing compared with L-30
Summary
The conditions of space flight have a significant effect on the physiological processes in the human body, yet the molecular mechanisms driving physiological changes remain unknown. Space flight has significant influence on cardiovascular system function due to fluid redistribution and modification mechanisms involved in the regulation of blood pressure. Endothelial cells are active functioning elements of the CVS that participate in the factors affecting adaptation to space flight. There were three distinct groups of proteins: 1) proteins with post-flight protein concentrations remaining stable; 2) proteins whose concentrations recovered slowly; and 3) proteins whose concentrations recovered rapidly to their pre-flight levels We reanalyze this data set to reveal the reason for the decreased concentrations of these proteins with subsequent correlation with states of water and electrolytic exchange in cosmonauts in the final flight period. The previous analysis was aimed at identifying proteins involved in the adaptation process to the conditions of terrestrial gravity, and mainly, the dynamics of proteins’ level recovery were examined by looking at samples collected on the seventh day, while in the current study, the mechanism of changes in protein concentrations from samples taken on the first day after flight was examined
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