Endothelial dysfunction markers and immune response indices in cosmonauts' blood after long-duration space flights.

Space flight factors are known to cause a malfunction in the human immune system and lead to damage to blood vessels. The hemostatic function of endothelium during space missions and its interaction with human immunity has not been determined so far. In this work, we investigated the markers of endothelial activation and damage (plasma concentrations of soluble thrombomodulin fraction (sTM), von Willebrand factor (vWF), highly sensitive C-reactive protein (hs-CRP)), as well as the level of D-dimer and compared them to the immunological parameters characterizing the state of human humoral and cellular immunity. The immune status of long-duration ISS crewmembers was assessed by whole-blood testing, and comprehensive postflight immune assessment included the analysis of leukocyte distribution. Flow cytometry was applied to determine the absolute counts and the percentage of lymphocyte subsets: B cells (CD19+), T cells (CD3+, CD3+CD4+, CD3+CD8+), NK cells (CD3-CD16+CD56+, CD11b+CD56+), and activated subsets (CD3+CD25+ and CD3+HLA-DR+). The in vitro basal cytokine production was investigated in whole blood cell culture. The cytokines IFN-gamma, IL-1-beta, IL-4, IL-6, IL-10, IL-18, and TNF-alpha were measured in plasma and the 24-h supernatants by a sensitive enzyme-linked immunosorbent assay. A significant increase in the plasma levels of vWF and hs-CRP and a decrease in the concentration of sTM after spaceflights were detected. Divergent changes in the parameters characterizing the state of the immune system were observed. We propose that the changes revealed may lead to an increase in the procoagulant activity of blood plasma, suppression of protein C activation and thrombin inhibition, as well as to an increase in the adhesive-aggregate potential of platelets, especially in case of changes in the rheological characteristics of blood flow during re-adaptation to ground conditions. We also speculate that the immune system might play an important role in vessel damage during long-duration missions.

The impact of short-term confinement on human innate immunity.

During space missions cosmonauts are exposed to a myriad of distinct stressors such as radiation, overloads, weightlessness, radiation, isolation in artificial environmental conditions, which causes changes in immune system. During space flights it is very difficult to determine the particular factor associated with the observed immunological responses. This makes ground-based experiments examining the effect of each space flight associated factor along of particular value. Determining mechanisms causing alterations in cosmonauts' immunity can lead to potential targets for different countermeasures. In the current article we present the study of the early period of adaptation of human innate immunity of 6 healthy test-subjects, 4 males and 2 females aged 25 through 40, to isolation factors (hypodynamia, psychological stress, artificial environment). We measured multiple parameters characterizing innate immunity status in blood samples at chosen time points before, during and after the mission. In the experiment, highly enhanced cytokine responses were observed upon ex vivo antigen stimulations in comparison to baseline values. For cellular parameters we found multidirectional dynamics with a persistent prevalence of increasing TLRs+ monocytes as well as TLRs expression. Our study provides evidence that even a short-term confinement leads to immune changes in healthy humans that may trigger aberrant immune response.

[Chromato-mass spectrometric analysis of urine proteins associated with the functions of Toll-receptors in a healthy person under conditions of 17-day isolation.] / Хромато-масс-спектрометрический анализ белков мочи, ÑÐ¾Ð¿Ñ€ÑÐ¶ÐµÐ½Ð½Ñ‹Ñ Ñ функциями Toll-рецепторов у здорового человека в ÑƒÑÐ»Ð¾Ð²Ð¸ÑÑ 17-суточной изоляции.

Under controlled conditions of 17-day isolation (Sirius-17 experiment), the protein composition of urine was studied in 6 healthy test volunteers-3 women and 3 men. Collection of samples in the form of a second freely separated morning urine fraction was carried out in the background (seven days before the experiment), as well as 1 day after the end of exposure. Chromatographic-mass-spectrometric semi-quantitative analysis of the protein composition of samples was performed on a system consisting of an Agilent 1100 chromatograph and an LTQ-FT Ultra hybrid mass spectrometer using bioinformatics resources UniProtKB, GeneOntology. An asymptomatic change in the immune defense system of kidney tissue after isolation in a closed hermetic object is associated with a change in the content of 7 proteins that provide functional activity of the TLR tubules of the kidneys - FcRIII, MUC1, Galectin-3, Ficolin-2, APOA1, FLNA, FCGR3A and Clusterin. These proteins are found to be useful biomarkers in the study of physiology and kidney diseases. They can be attributed to candidates for protein markers of the initial stages of impaired recognition by the epithelium of renal tubules of bacteria with known pathogenic potential.

STATUS OF THE SYSTEM OF SIGNALING PATTERN RECOGNITION RECEPTORS OF MONOCYTES AND GRANULOCYTES IN COSMONAUTS' PERIPHERAL BLOOD BEFORE AND AFTER LONG-DURATION MISSIONS TO THE INTERNATIONAL SPACE STATION.

The system of signaling pattern recognition receptors was studied in 8 cosmonauts aged 35 to 56 years before and after (R+) long-duration missions to the International space station. Peripheral blood samples were analyzed for the content of monocytes and granulocytes that express the signaling pattern recognition Toll- like (TLR) receptors localized as on cell surface (TLR1, TLR2, TLR4, TLR5, TLR6), so inside cells (TLR3, TLR8, TLR9). In parallel, serum concentrations of TLR2 (HSP60) and TLR4 ligands (HSP70, HMGB1) were measured. The results of investigations showed growth of HSP60, HSP70 and HMGB1 concentrations on R+1. In the;majority of cosmonauts increases in endogenous ligands were followed by growth in the number of both monocytes and granulocytes that express TLR2 1 TLR4. This consistency gives ground to assume that changes in the system of signaling pattern recognition receptors can stem .from the predominantly endogenous ligands' response to the effects of long-duration space flight on human organism.

[TOLL-LIKE RECEPTORS IN COSMONAUT'S PERIPHERAL BLOOD CELLS AFTER LONG-DURATION MISSIONS TO THE INTERNATIONAL SPACE STATION].

Studies of Toll-like receptors (TLR) in 20 cosmonauts-members of long-duration (124-199-day) missions to the International space station evidenced changes in relative and absolute counts of peripheral blood monocytes with TLR2, TLR4 and TLR6 on the surface, expression of TLR2 and TLR6 genes, and genes of molecules involved in the TLR signaling pathway and TLR-related NF-KB-, JNK/p38- and IRF pathways on the day of return to Earth. The observed changes displayed individual variability.

[Status of the osteoclast-activating system in cosmonauts after long-duration missions to the International Space Station].

The results of studying the system of osteoprotegerin/ receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) in 22 cosmonauts after long-duration (124 to 199 days) ISS missions are presented. Immediately on return to 1 g, changes were observed in OPG and RANKL serum levels and the ability to produce unstimulated and stimulated PGA of peripheral blood mononuclear cells in vitro. Individual variability of these changes was noticed. Our findings suggest that the cytokine OPG/RANKL-system is involved in bone remodeling in members of long-duration space missions.

[Immunological aspects of a piloted mission to Mars].

The paper deals with the results of the effects of 520-day isolation and confinement modeling some elements of a mission to Mars on the immune system. Longitudinal analyses revealed that the mechanisms of adaptive response of the human immune system to the conditions of extremely long isolation led to a change of the parameters, characterizing innate and adaptive immunity. Among them the most important are: changes in the signaling PRRs--TLR, manifested in the reduction of the percentage of circulating monocytes and granulocytes expressed on its own surfaces TLR2, TLR4 and TLR6, decreases early NK cell activation potential, increases in the percentage T- and B-lymphocytes, that expressed early activation marker CD69 after adequate stimulation, and in production of cytokines in response to PHA stimulation. The active mobilization of the mechanisms of adaptive immunity, the implementation of the function of the level of immunity to a qualitatively different level, apparently, should be taken as a sign of adaptive adjustment of an organism in response to the complex influence of unfavorable factors, aimed at the preservation of immune homeostasis.

[Congenital human immunity during 5-day dry immersion].

The system of congenital immunity was studied in 12 essentially healthy males 18 to 26 years of age subjected to 5-day dry immersion without use of countermeasures. Peripheral blood was analyzed for monocytes, granulocytes and lymphocytes expressing the TLR2+, TLR4+, TLR6+, CD11b+, CD14+, CD16+, CD18+, CD24+, CD36+, CD54+, CD56+ and CD206+ receptors. Expression of early activation marker CD69 on lymphocytes-natural killers was studied in unstimulated and interleukin-2 activated mononuclear cell cultures. The negative shifts in the congenital immunity system in some volunteers at the end of immersion and during recovery can be considered as warnings about depletion of the system reserve and increase of the risk of infectious diseases such as caused by normal microflora which typically does not provoke pathological reactions of the host.

[Analysis of the relationships between the psychophysiological status and system of adaptive immunity in the conditions of 5-day dry immersion].

Relationships of the T- and B-components of adaptive immunity and the psychophysiological status were studied in 14 volunteers for the experiment with 5-d dry immersion (DI) w/o countermeasures. Comparison of frequency of deviations in immunity parameters of psychologically different subjects demonstrated the highest frequency in non-anxious and extravert individuals on day-5 in DI. These differences in immune reactions as a function of psychological type and temperament point to existence of a neuroimmune typology and, therefore, the necessity of concurrent immunologic and psychological investigations in order to develop separate measures of rehabilitation from and prevention of stress in people with polar psychological status.

[Indicators of innate and adaptive immunity of cosmonauts after long-term space flight to international space station].

Results of innate and adaptive immunity indicators research at 12 cosmonauts who took part in long (128-215 days) expeditions to the International space station (ISS) are presented. It is shown that a space flight can lead to deflection of deviations in human immune system. These shifts occurred in decrease of phagocytes, NK, T-lymphocytes functional activity and also in abilities of immunocompetent cells to synthesize cytokines. Significant individual changes are noted in reaction of immune system to the long term space flight conditions specifying on individual predisposition to development of immune reactance infringements in the conditions of varying gravitational influences.