Characteristics of blood plasma proteome changes associated with the hemorrhagic purpura of cosmonauts on the first day after long-term space missions.

The interest in the role of the gravitational factor during landing after long-term space flights (SF) leads to the search for various innovative approaches to assessing the compliance of external changes observed by clinicians. The results of special research methods such as Omics technologies that may reflect physiological responses to the conditions created during landing are of great interest. Our purpose is to compare the blood plasma proteome changes associated with the trauma and endothelial dysfunction processes prior to launch and on the day of landing, as well as the groups of cosmonauts with and without the secondary hemorrhagic purpura. In our study, the concentrations of 125 plasma proteins in 18 Russian cosmonauts, measured using targeted proteomic analysis based on liquid chromatography and tandem mass spectrometry were analyzed. The results reveal the trends of 12 proteins participating in the processes that trigger hemorrhagic purpura under the effect of re-entry g-forces. Exposure to intense g-forces and return to the gravity are the key factors for external manifestations of changes in the body systems induced by a long-term stay in space microgravity. Our results may be useful for further research to experts in gravitational physiology, aviation and space medicine.

[Cosmonauts' tolerance of the chest-back G-loads during ballistic and automatically controlled descents of space vehicles].

Analysis of cosmonauts' +Gx tolerance on the stage of ballistic or automatically controlled Soyuz descent after missions to the International space station of varying duration was performed. As compared with automatically controlled descents, tolerance of descent re-entry +G(x) following short (8-14 d) missions was marked by reliably more frequent instances of visual disorders, difficult breathing, sensation of a lump in the throat and vestibulovegetative disorders (p < 0.05). The ballistic but not controlled re-entry after long-term mission provoked visual disorders, difficulties with breathing and speech, and vestibulovegetative disorders more often (p < 0.05). A considerable HR rise due to the ballistic rather than control descent was associated with re-entry and the main parachute re-hooking for symmetrical suspension; respiration rate was the highest during parachuting. By and large, these factual data infer that the ballistic descent after various periods in spaceflight microgravity, especially after extended space missions (164-169 d), led to a dramatic loss in the body functional reserves.