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1.
Artigo em Inglês | MEDLINE | ID: mdl-31751178

RESUMO

As the international space community plans for manned missions to Mars, spaceflight associated immune dysregulation has been identified as a potential risk to the health and safety of the flight crew. There is a need to determine if salivary antimicrobial proteins - which act as a first line of innate immune defense against multiple pathogens - are altered in response to long-duration (>6-months) missions. We collected 7 consecutive days of saliva samples from 8 international space station (ISS) crewmembers and 7 ground-based controls at 9 separate mission time points; ~180 and ~60 days before launch (L-180/L-60), on orbit at flight day ~10 and ~90 (FD10/FD90) and ~1-day before return (R-1), and at R+0, R+18, R+33 and R+66 days after returning to Earth. We found that salivary sIgA, lysozyme, LL-37, and the cortisol to DHEA ratio were elevated in the ISS crew before (L-180) and during (FD10/FD90) the mission. 'Rookie' crewmembers embarking on their first spaceflight mission had lower levels of salivary sIgA, but increased levels of α-amylase, lysozyme and LL-37 during and after the mission compared to the 'veteran' crew who had previously flown. Latent herpesvirus reactivation was distinct to the ~6-month mission crewmembers who performed extravehicular activity ('spacewalks'). Crewmembers who shed at least one latent virus had higher cortisol levels compared to those who did not shed. We conclude that long-duration spaceflight alters the concentration and/or secretion of several antimicrobial proteins in saliva, some of which are related to crewmember flight experience, biomarkers of stress and latent viral reactivation.

2.
Sci Rep ; 9(1): 9911, 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31289321

RESUMO

Over the course of a mission to the International Space Station (ISS) crew members are exposed to a number of stressors that can potentially alter the composition of their microbiomes and may have a negative impact on astronauts' health. Here we investigated the impact of long-term space exploration on the microbiome of nine astronauts that spent six to twelve months in the ISS. We present evidence showing that the microbial communities of the gastrointestinal tract, skin, nose and tongue change during the space mission. The composition of the intestinal microbiota became more similar across astronauts in space, mostly due to a drop in the abundance of a few bacterial taxa, some of which were also correlated with changes in the cytokine profile of crewmembers. Alterations in the skin microbiome that might contribute to the high frequency of skin rashes/hypersensitivity episodes experienced by astronauts in space were also observed. The results from this study demonstrate that the composition of the astronauts' microbiome is altered during space travel. The impact of those changes on crew health warrants further investigation before humans embark on long-duration voyages into outer space.

3.
Science ; 364(6436)2019 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-30975860

RESUMO

To understand the health impact of long-duration spaceflight, one identical twin astronaut was monitored before, during, and after a 1-year mission onboard the International Space Station; his twin served as a genetically matched ground control. Longitudinal assessments identified spaceflight-specific changes, including decreased body mass, telomere elongation, genome instability, carotid artery distension and increased intima-media thickness, altered ocular structure, transcriptional and metabolic changes, DNA methylation changes in immune and oxidative stress-related pathways, gastrointestinal microbiota alterations, and some cognitive decline postflight. Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within 6 months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted. These multiomic, molecular, physiological, and behavioral datasets provide a valuable roadmap of the putative health risks for future human spaceflight.


Assuntos
Adaptação Fisiológica , Astronautas , Voo Espacial , Imunidade Adaptativa , Peso Corporal , Artérias Carótidas/diagnóstico por imagem , Espessura Intima-Media Carotídea , Dano ao DNA , Metilação de DNA , Microbioma Gastrointestinal , Instabilidade Genômica , Humanos , Masculino , Homeostase do Telômero , Fatores de Tempo , Estados Unidos , United States National Aeronautics and Space Administration
4.
Artigo em Inglês | MEDLINE | ID: mdl-30382809

RESUMO

Maintaining astronaut health during space travel is paramount for further human exploration of the solar system beyond Earth's orbit. Of concern are potential dysregulations in immunity, which could impair protection against cancer and latent viral reactivation. We compared changes in NK-cell phenotype and function in 8 crewmembers who completed a ~6-month mission to the International Space Station (ISS) with healthy controls who remained on Earth. Assessments were made before [(-180 and -60 days before launch (L)], during [flight day (FD) +90 and 1 day prior to return (R) -1], and after the mission at days R+0, R+18, R+33, and R+66. These samples, plus an additional in flight sample (FD+180), were collected from a crewmember who spent 340 days (~1-year) on the ISS. NK-cell cytotoxic activity (NKCA) against K562 leukemia targets in vitro was reduced by ~50% at FD+90 in ISS crew but not controls. This decrease was more pronounced in 'rookie' compared to 'veteran' crewmembers. The ~1-year mission crewmember did not show declines in NKCA against K562 until late in the mission (R-1 and R+0). NK-cell numbers, expression of activating and inhibitory receptors, target cell binding, and expression and degranulation of perforin and granzyme b were unaltered with spaceflight. Similarly, exposing the NK-92 cell line to sera collected at different mission time-points did not affect NKCA. This is the first study to report impaired NK-cell function during long duration space travel. Countermeasures may be needed to mitigate immune system impairment in exploration class mission crew during long duration spaceflight missions.

5.
Artigo em Inglês | MEDLINE | ID: mdl-30496712

RESUMO

Long duration spaceflights reportedly induce immune dysregulation, which is considered a risk to astronaut safety and mission success. Recent studies have examined the impact of spaceflight on markers of adaptive and innate immunity, but no study to date has comprehensively evaluated humoral immunity and serological markers of B-cell function. The aim of this study was to characterize changes in B-cell numbers and phenotypes, along with plasma immunoglobulins and polyclonal free light chains (FLC) - near 'real-time' biomarkers of immunoglobulin synthesis - in response to a ~6-month mission to the International Space Station (ISS). Blood samples were collected before flight, during ("Early flight", "Mid-flight" and "Late flight"), immediately upon return and during a recovery period (R+18, R+30/R+33 and R+60/R+66) from 23 ISS crewmembers. B-cell counts and phenotypes were measured throughout the duration of the mission, along with total plasma immunoglobulin (Ig) and FLC levels. There was no effect of spaceflight on the number and proportion of the different B-cell subsets. There was no difference in kappa FLC between pre-flight samples and either in-flight or recovery samples (p>0.05), and only a marginal reduction was observed in lambda FLC levels upon return to Earth (p<0.05). Furthermore, IgG and IgM remained unchanged during and after spaceflight, when compared to pre-flight values (p>0.05). Of note, plasma IgA concentrations were elevated in-flight when compared to baseline and recovery values (p<0.05). These results indicate that B-cell homeostasis is maintained during long duration spaceflight, advocating for potential in-flight vaccination as viable countermeasures against viral reactivation during exploration-class missions.

6.
Front Immunol ; 9: 1437, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30018614

RESUMO

Recent studies have established that dysregulation of the human immune system and the reactivation of latent herpesviruses persists for the duration of a 6-month orbital spaceflight. It appears certain aspects of adaptive immunity are dysregulated during flight, yet some aspects of innate immunity are heightened. Interaction between adaptive and innate immunity also seems to be altered. Some crews experience persistent hypersensitivity reactions during flight. This phenomenon may, in synergy with extended duration and galactic radiation exposure, increase specific crew clinical risks during deep space exploration missions. The clinical challenge is based upon both the frequency of these phenomena in multiple crewmembers during low earth orbit missions and the inability to predict which specific individual crewmembers will experience these changes. Thus, a general countermeasure approach that offers the broadest possible coverage is needed. The vehicles, architecture, and mission profiles to enable such voyages are now under development. These include deployment and use of a cis-Lunar station (mid 2020s) with possible Moon surface operations, to be followed by multiple Mars flyby missions, and eventual human Mars surface exploration. Current ISS studies will continue to characterize physiological dysregulation associated with prolonged orbital spaceflight. However, sufficient information exists to begin consideration of both the need for, and nature of, specific immune countermeasures to ensure astronaut health. This article will review relevant in-place operational countermeasures onboard ISS and discuss a myriad of potential immune countermeasures for exploration missions. Discussion points include nutritional supplementation and functional foods, exercise and immunity, pharmacological options, the relationship between bone and immune countermeasures, and vaccination to mitigate herpes (and possibly other) virus risks. As the immune system has sentinel connectivity within every other physiological system, translational effects must be considered for all potential immune countermeasures. Finally, we shall discuss immune countermeasures in the context of their individualized implementation or precision medicine, based on crewmember specific immunological biases.

7.
Allergy ; 2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29978486

RESUMO

BACKGROUND: Antarctica is a challenging environment for humans. It serves as a spaceflight ground analog, reflecting some conditions of long-duration exploration class space missions. The French-Italian Concordia station in interior Antarctica is a high-fidelity analog, located 1000 km from the coast, at an altitude of 3232 m. The aim of this field study was to characterize the extent, dynamics, and key mechanisms of the immune adaptation in humans overwintering at Concordia for 1 year. METHODS: This study assessed immune functions in fourteen crewmembers. Quantitative and phenotypic analyses from human blood were performed using onsite flow cytometry together with specific tests on receptor-dependent and receptor-independent functional innate and adaptive immune responses. Transcriptome analyses and quantitative identification of key response genes were assessed. RESULTS: Dynamic immune activation and a two-step escalation/activation pattern were observed. The early phase was characterized by moderately sensitized global immune responses, while after 3-4 months, immune responses were highly upregulated. The cytokine responses to an ex vivo stimulation were markedly raised above baseline levels. These functional observations were reflected at the gene transcriptional level in particular through the modulation of hypoxia-driven pathways. CONCLUSIONS: This study revealed unique insights into the extent, dynamics, and genetics of immune dysfunctions in humans exposed for 1 year to the Antarctic environment at the Concordia station. The scale of immune function was imbalanced toward a sensitizing of inflammatory pathways.

8.
Sci Rep ; 7(1): 16180, 2017 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-29170507

RESUMO

Humans' core body temperature (CBT) is strictly controlled within a narrow range. Various studies dealt with the impact of physical activity, clothing, and environmental factors on CBT regulation under terrestrial conditions. However, the effects of weightlessness on human thermoregulation are not well understood. Specifically, studies, investigating the effects of long-duration spaceflight on CBT at rest and during exercise are clearly lacking. We here show that during exercise CBT rises higher and faster in space than on Earth. Moreover, we observed for the first time a sustained increased astronauts' CBT also under resting conditions. This increase of about 1 °C developed gradually over 2.5 months and was associated with augmented concentrations of interleukin-1 receptor antagonist, a key anti-inflammatory protein. Since even minor increases in CBT can impair physical and cognitive performance, both findings have a considerable impact on astronauts' health and well-being during future long-term spaceflights. Moreover, our findings also pinpoint crucial physiological challenges for spacefaring civilizations, and raise questions about the assumption of a thermoregulatory set point in humans, and our evolutionary ability to adapt to climate changes on Earth.

9.
NPJ Microgravity ; 3: 11, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28649633

RESUMO

Reactivation of latent herpes viruses was measured in 23 astronauts (18 male and 5 female) before, during, and after long-duration (up to 180 days) spaceflight onboard the international space station . Twenty age-matched and sex-matched healthy ground-based subjects were included as a control group. Blood, urine, and saliva samples were collected before, during, and after spaceflight. Saliva was analyzed for Epstein-Barr virus, varicella-zoster virus, and herpes simplex virus type 1. Urine was analyzed for cytomegalovirus. One astronaut did not shed any targeted virus in samples collected during the three mission phases. Shedding of Epstein-Barr virus, varicella-zoster virus, and cytomegalovirus was detected in 8 of the 23 astronauts. These viruses reactivated independently of each other. Reactivation of Epstein-Barr virus, varicella-zoster virus, and cytomegalovirus increased in frequency, duration, and amplitude (viral copy numbers) when compared to short duration (10 to 16 days) space shuttle missions. No evidence of reactivation of herpes simplex virus type 1, herpes simplex virus type 2, or human herpes virus 6 was found. The mean diurnal trajectory of salivary cortisol changed significantly during flight as compared to before flight (P = 0.010). There was no statistically significant difference in levels of plasma cortisol or dehydoepiandosterone concentrations among time points before, during, and after flight for these international space station crew members, although observed cortisol levels were lower at the mid and late-flight time points. The data confirm that astronauts undertaking long-duration spaceflight experience both increased latent viral reactivation and changes in diurnal trajectory of salivary cortisol concentrations.

10.
NPJ Microgravity ; 3: 10, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28649632

RESUMO

Three-dimensional models of human intestinal epithelium mimic the differentiated form and function of parental tissues often not exhibited by two-dimensional monolayers and respond to Salmonella in key ways that reflect in vivo infections. To further enhance the physiological relevance of three-dimensional models to more closely approximate in vivo intestinal microenvironments encountered by Salmonella, we developed and validated a novel three-dimensional co-culture infection model of colonic epithelial cells and macrophages using the NASA Rotating Wall Vessel bioreactor. First, U937 cells were activated upon collagen-coated scaffolds. HT-29 epithelial cells were then added and the three-dimensional model was cultured in the bioreactor until optimal differentiation was reached, as assessed by immunohistochemical profiling and bead uptake assays. The new co-culture model exhibited in vivo-like structural and phenotypic characteristics, including three-dimensional architecture, apical-basolateral polarity, well-formed tight/adherens junctions, mucin, multiple epithelial cell types, and functional macrophages. Phagocytic activity of macrophages was confirmed by uptake of inert, bacteria-sized beads. Contribution of macrophages to infection was assessed by colonization studies of Salmonella pathovars with different host adaptations and disease phenotypes (Typhimurium ST19 strain SL1344 and ST313 strain D23580; Typhi Ty2). In addition, Salmonella were cultured aerobically or microaerobically, recapitulating environments encountered prior to and during intestinal infection, respectively. All Salmonella strains exhibited decreased colonization in co-culture (HT-29-U937) relative to epithelial (HT-29) models, indicating antimicrobial function of macrophages. Interestingly, D23580 exhibited enhanced replication/survival in both models following invasion. Pathovar-specific differences in colonization and intracellular co-localization patterns were observed. These findings emphasize the power of incorporating a series of related three-dimensional models within a study to identify microenvironmental factors important for regulating infection.

11.
J Med Virol ; 89(9): 1686-1689, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28295404

RESUMO

Varicella zoster virus (VZV) in saliva from six herpes zoster patients and one chickenpox patient was found to be exclusively associated with epithelial cells by confocal microscopy. VZV localization with antibody specific to the VZV glycoprotein E was detected primarily on the membrane but was also inside the cell. Epithelial cells with VZV were still present in saliva in one out of two tested zoster patients after 10 months of recovery. Saliva from healthy controls (non-shingles patients, n = 5) did not show any sign of VZV by polymerase chain reaction or by confocal microscopy. No VZV was found in the liquid fraction of saliva. Further work is required to understand the movement of VZV in the saliva cells of infected patients.


Assuntos
Herpes Zoster/virologia , Herpesvirus Humano 3/isolamento & purificação , Saliva/virologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Epiteliais/virologia , Feminino , Humanos , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
12.
JCI Insight ; 1(12): e88787, 2016 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-27699228

RESUMO

Following the advent of molecular assays that measure T cell receptor excision circles (TRECs) present in recent thymic emigrants, it has been conclusively shown that thymopoiesis persists in most adults, but that functional output decreases with age, influencing the maintenance of a diverse and functional T cell receptor (TCR) repertoire. Space flight has been shown to result in a variety of phenotypic and functional changes in human T cells and in the reactivation of latent viruses. While space flight has been shown to influence thymic architecture in rodents, thymopoiesis has not previously been assessed in astronauts. Here, we assessed thymopoiesis longitudinally over a 1-year period prior to and after long-term space flight (median duration, 184 days) in 16 astronauts. While preflight assessments of thymopoiesis remained quite stable in individual astronauts, we detected significant suppression of thymopoiesis in all subjects upon return from space flight. We also found significant increases in urine and plasma levels of endogenous glucocorticoids coincident with the suppression of thymopoiesis. The glucocorticoid induction and thymopoiesis suppression were transient, and they normalized shortly after return to Earth. This is the first report to our knowledge to prospectively demonstrate a significant change in thymopoiesis in healthy individuals in association with a defined physiologic emotional and physical stress event. These results suggest that suppression of thymopoiesis has the potential to influence the maintenance of the TCR repertoire during extended space travel. Further studies of thymopoiesis and endogenous glucocorticoids in other stress states, including illness, are warranted.


Assuntos
Astronautas , Linfopoese , Voo Espacial , Estresse Fisiológico/imunologia , Linfócitos T/citologia , Glucocorticoides/sangue , Glucocorticoides/urina , Humanos
13.
NPJ Microgravity ; 2: 16025, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28725735

RESUMO

Genomic and epigenomic studies require the precise transfer of microliter volumes among different types of tubes in order to purify DNA, RNA, or protein from biological samples and subsequently perform analyses of DNA methylation, RNA expression, and chromatin modifications on a genome-wide scale. Epigenomic and transcriptional analyses of human blood cells, for example, require separation of purified cell types to avoid confounding contributions of altered cellular proportions, and long-term preservation of these cells requires their isolation and transfer into appropriate freezing media. There are currently no protocols for these cellular isolation procedures on the International Space Station (ISS). Currently human blood samples are either frozen as mixed cell populations (within the CPT collection tubes) with poor yield of viable cells required for cell-type isolations, or returned under ambient conditions, which requires timing with Soyuz missions. Here we evaluate the feasibility of translating terrestrial cell purification techniques to the ISS. Our evaluations were performed in microgravity conditions during parabolic atmospheric flight. The pipetting of open liquids in microgravity was evaluated using analog-blood fluids and several types of pipette hardware. The best-performing pipettors were used to evaluate the pipetting steps required for peripheral blood mononuclear cell (PBMC) isolation following terrestrial density-gradient centrifugation. Evaluation of actual blood products was performed for both the overlay of diluted blood, and the transfer of isolated PBMCs. We also validated magnetic purification of cells. We found that positive-displacement pipettors avoided air bubbles, and the tips allowed the strong surface tension of water, glycerol, and blood to maintain a patent meniscus and withstand robust pipetting in microgravity. These procedures will greatly increase the breadth of research that can be performed on board the ISS, and allow improvised experimentation by astronauts on extraterrestrial missions.

14.
NPJ Microgravity ; 2: 16040, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28725745

RESUMO

Dysregulation of the immune system occurs during spaceflight and may represent a crew health risk during exploration missions because astronauts are challenged by many stressors. Therefore, it is crucial to understand the biology of immune modulation under spaceflight conditions in order to be able to maintain immune homeostasis under such challenges. In the framework of the THESEUS project whose aim was to develop an integrated life sciences research roadmap regarding human space exploration, experts working in the field of space immunology, and related disciplines, established a questionnaire sent to scientists around the world. From the review of collected answers, they deduced a list of key issues and provided several recommendations such as a maximal exploitation of currently available resources on Earth and in space, and to increase increments duration for some ISS crew members to 12 months or longer. These recommendations should contribute to improve our knowledge about spaceflight effects on the immune system and the development of countermeasures that, beyond astronauts, could have a societal impact.

15.
J Interferon Cytokine Res ; 34(10): 778-86, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24702175

RESUMO

Aspects of immune system dysregulation associated with long-duration spaceflight have yet to be fully characterized and may represent a clinical risk to crewmembers during deep space missions. Plasma cytokine concentration may serve as an indicator of in vivo physiological changes or immune system mobilization. The plasma concentrations of 22 cytokines were monitored in 28 astronauts during long-duration spaceflight onboard the International Space Station. Blood samples were collected 3 times before flight, 3-5 times during flight (depending on mission duration), at landing, and 30 days after landing. Analysis was performed by bead array immunoassay. With few exceptions, minimal detectable mean plasma concentrations were observed at baseline (launch minus 180) for innate inflammatory cytokines or adaptive regulatory cytokines; however, interleukin (IL)-1ra and several chemokines and growth factors were constitutively present. An increase in the plasma concentration, tumor necrosis factor-α (TNFα), IL-8, IL-1ra, thrombopoietin (Tpo), vascular endothelial growth factor (VEGF), C-C motif chemokine ligand 2 (CCL2), chemokine ligand 4/macrophage inhibitory protein 1b (CCL4), and C-X-C motif chemokine 5/epithelial neutrophil-activating protein 78 (CXCL5) was observed associated with spaceflight. No significant alterations were observed during or following spaceflight for the inflammatory or adaptive/T-regulatory cytokines: IL-1α, IL-1ß, IL-2, interferon-gamma (IFN-γ), IL-17, IL-4, IL-5, IL-10, G-CSF, GM-CSF, FGF basic, CCL3, or CCL5. This pattern of cytokine dysregulation suggests multiple physiological adaptations persist during flight, including inflammation, leukocyte recruitment, angiogenesis, and thrombocyte regulation.


Assuntos
Adaptação Fisiológica/imunologia , Citocinas/sangue , Hormônios/imunologia , Voo Espacial , Imunidade Adaptativa , Coagulação Sanguínea , Movimento Celular , Feminino , Seguimentos , Humanos , Imunidade Inata , Imunomodulação , Masculino , Pessoa de Meia-Idade , Neovascularização Fisiológica , Fatores de Tempo
16.
FASEB J ; 28(3): 1486-98, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24334706

RESUMO

Astronauts are exposed to increased body iron stores and radiation, both of which can cause oxidative damage leading to negative health effects. The purpose of this study was to investigate combined effects of high dietary iron (650 mg/kg diet) and radiation exposure (0.375 Gy cesium-137 every other day for 16 d) on markers of oxidative stress, immune system function, and colon mucosal environment in male Sprague-Dawley rats (n=8/group). Control rats consumed adequate iron (45 mg/kg diet) and were not irradiated. Combined treatments increased liver glutathione peroxidase, serum catalase, and colon myeloperoxidase while decreasing total fecal short-chain fatty acid concentrations. The high-iron diet alone increased leukocyte count. Radiation decreased the T-cell CD4:CD8 ratio. Plasma iron was negatively correlated with cytokine production in activated monocytes. Genes involved in colon microbial signaling, immune response, and injury repair were altered by radiation. Genes involved with injury repair and pathogen recognition changed with dietary iron. These data demonstrate that dietary iron and radiation, alone and combined, contribute to oxidative stress that is related to immune system alterations in circulation and the colon. The model presented may help us better understand the changes to these systems that have been identified among astronauts.


Assuntos
Colo/fisiologia , Dieta , Sistema Imunitário/fisiologia , Ferro/administração & dosagem , Estresse Oxidativo , Radiação Ionizante , Animais , Mucosa Intestinal/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley
17.
Open J Med Microbiol ; 2(3)2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24409401

RESUMO

A 41-year-old woman developed skin lesions on her upper back and arm. Initially, a definitive diagnosis could not be made. Subsequently, PCR detected VZV DNA in skin lesions and saliva. Immediate antiviral treatment led to a quick recovery without complicating prolonged fatigue and weakness typically seen in adults with varicella.

18.
Aviat Space Environ Med ; 80(5 Suppl): A37-44, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19476168

RESUMO

INTRODUCTION: As logistical access for space research becomes more limited and NASA prepares for exploration-class missions, ground-based spaceflight analogs will increase in importance for biomedical countermeasures development. A monitoring of immune parameters was performed during the NASA Flight Analogs Project bed rest study (without countermeasure); to establish 'control' data against which future studies (with countermeasure) will be evaluated. Some of the countermeasures planned to be evaluated in future studies may impact immune function. METHODS: The immune assessment consisted of: leukocyte subset distribution, early T cell activation, intracellular cytokine profiles, latent viral reactivation, virus specific T cell levels and function, stress hormone levels, and a behavioral assessment using stress questionnaires. RESULTS: In general, subjects did not display altered peripheral leukocyte subsets, constitutive immune activation, altered T cell function, or significant latent viral reactivation (EBV, VZV). Levels of constitutively activated T cells (CD8+/CD69+) and virus-specific T cells (CMV and EBV) decreased during the study. Cortisol levels (plasma and saliva) did not vary significantly during 90-d bed rest. CONCLUSIONS: These data demonstrate the absence of significant immune system alteration and physiological stress during 90-d bed rest, and establish control data against which future studies (including countermeasures) may be compared.


Assuntos
Repouso em Cama , Decúbito Inclinado com Rebaixamento da Cabeça/efeitos adversos , Sistema Imunitário/imunologia , Voo Espacial , Estresse Fisiológico , Viroses/imunologia , Adaptação Fisiológica , Adulto , Citocinas/análise , DNA Viral/análise , Feminino , Nível de Saúde , Humanos , Masculino , Estudos Prospectivos , Psicometria , Estresse Fisiológico/imunologia , Estresse Psicológico/imunologia , Inquéritos e Questionários , Linfócitos T/imunologia , Fatores de Tempo , Estados Unidos , United States National Aeronautics and Space Administration , Ativação Viral/imunologia , Ausência de Peso/efeitos adversos
19.
Aviat Space Environ Med ; 79(9): 835-43, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18785351

RESUMO

INTRODUCTION: Immune system dysregulation has been demonstrated to occur during and immediately following spaceflight. If found to persist during lengthy flights, this phenomenon could be a serious health risk to crewmembers participating in lunar or Mars missions. METHODS: A comprehensive postflight immune assessment was performed on 17 short-duration Space Shuttle crewmembers and 8 long-duration International Space Station (ISS) crewmembers. Testing consisted of peripheral leukocyte subset analysis, early T cell activation potential, and intracellular/secreted cytokine profiles. RESULTS: For Shuttle crewmembers, the distribution of the peripheral leukocyte subsets was found to be altered postflight. Early T cell activation was elevated postflight; however, the percentage of T cell subsets capable of being stimulated to produce IL-2 and IFN gamma was decreased. The ratio of secreted IFN gamma:IL-10 following T cell stimulation declined after landing, indicating a Th2 shift. For the ISS crewmembers, some alterations in peripheral leukocyte distribution were also detected after landing. In contrast to Shuttle crewmembers, the ISS crewmembers demonstrated a statistically significant reduction in early T cell activation potential immediately postflight. The percentage of T cells capable of producing IL-2 was reduced, but IFN gamma percentages were unchanged. A reduction in the secreted IFN gamma:IL-10 ratio (Th2 shift) was also observed postflight in the ISS crewmembers. CONCLUSION: These data indicate that consistent peripheral phenotype changes and altered cytokine production profiles occur following spaceflight of both short and long duration; however, functional immune dysregulation may vary related to mission duration. In addition, a detectable Th2 cytokine shift appears to be associated with spaceflight.


Assuntos
Sistema Imunitário/imunologia , Voo Espacial , Células Th2/citologia , Ausência de Peso/efeitos adversos , Feminino , Citometria de Fluxo , Humanos , Sistema Imunitário/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fenótipo , Projetos Piloto , Linfócitos T/citologia , Linfócitos T/imunologia , Células Th2/imunologia , Fatores de Tempo
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