Differential effects of hypergravity on immune dysfunctions induced by simulated microgravity.

Microgravity (µg) is among the major stressors in space causing immune cell dysregulations. These are frequently expressed as increased pro-inflammatory states of monocytes and reduced activation capacities in T cells. Hypergravity (as artificial gravity) has shown to have beneficial effects on the musculoskeletal and cardiovascular system both as a countermeasure option for µg-related deconditioning and as "gravitational therapy" on Earth. Since the impact of hypergravity on immune cells is sparsely explored, we investigated if an application of "mild" mechanical loading of 2.8 g is able to avoid or treat µg-mediated immune dysregulations. For this, T cell and monocyte activation states and cytokine pattern were first analyzed after whole blood antigen incubation in simulated µg (s-µg) by using the principle of fast clinorotation or in hypergravity. Subsequent hypergravity countermeasure approaches were run at three different sequences: one preconditioning setting, where 2.8 g was applied before s-µg exposure and two therapeutic approaches in which 2.8 g was set either intermediately or at the end of s-µg. In single g-grade exposure experiments, monocyte pro-inflammatory state was enhanced in s-µg and reduced in hypergravity, whereas T cells displayed reduced activation when antigen incubation was performed in s-µg. Hypergravity application in all three sequences did not alleviate the increased pro-inflammatory potential of monocytes. However, in T cells the preconditioning approach restored antigen-induced CD69 expression and IFNγ secretion to 1 g control values and beyond. This in vitro study demonstrates a proof of concept that mild hypergravity is a gravitational preconditioning option to avoid adaptive immune cell dysfunctions induced by (s-)µg and that it may act as a booster of immune cell functions.

Dietary habits, traveling and the living situation potentially influence the susceptibility to SARS-CoV-2 infection: results from healthcare workers participating in the RisCoin Study.

PURPOSE: To explore occupational and non-occupational risk and protective factors for the coronavirus disease 2019 (COVID-19) in healthcare workers (HCWs). METHODS: Serum specimens and questionnaire data were obtained between October 7 and December 16, 2021 from COVID-19-vaccinated HCWs at a quaternary care hospital in Munich, Germany, and were analyzed in the RisCoin Study. RESULTS: Of 3,696 participants evaluated, 6.6% have had COVID-19 at least once. Multivariate logistic regression analysis identified working in patient care occupations (7.3% had COVID-19, 95% CI 6.4-8.3, Pr = 0.0002), especially as nurses, to be a potential occupation-related COVID-19 risk factor. Non-occupational factors significantly associated with high rates of the disease were contacts to COVID-19 cases in the community (12.8% had COVID-19, 95% CI 10.3-15.8, Pr < 0.0001), being obese (9.9% had COVID-19, 95% CI 7.1-13.5, Pr = 0.0014), and frequent traveling abroad (9.4% had COVID-19, 95% CI 7.1-12.3, Pr = 0.0088). On the contrary, receiving the basic COVID-19 immunization early during the pandemic (5.9% had COVID-19, 95% CI 5.1-6.8, Pr < 0.0001), regular smoking (3.6% had COVID-19, 95% CI 2.1-6.0, Pr = 0.0088), living with the elderly (3.0% had COVID-19, 95% CI 1.0-8.0, Pr = 0.0475), and frequent consumption of ready-to-eat meals (2.6% had COVID-19, 95% CI 1.1-5.4, Pr = 0.0045) were non-occupational factors potentially protecting study participants against COVID-19. CONCLUSION: The newly discovered associations between the living situation, traveling as well as dietary habits and altered COVID-19 risk can potentially help refine containment measures and, furthermore, contribute to new mechanistic insights that may aid the protection of risk groups and vulnerable individuals.

Questionnaire-based study of COVID-19 vaccination induced headache: evidence of clusters of adverse events.

BACKGROUND: The adverse events (AEs) after a Coronavirus disease 2019 (Covid-19) Pfizer-Biotech mRNA vaccination present a medical and epidemiological issue of increasing interest. Headache is the most frequent neurological adverse effect and generally the third most common adverse event after a Covid-19 vaccination, but only a few studies focus on the link between headache and other AEs after vaccination. This study aims to investigate the correlation between headaches and Covid-19 vaccination, as well as the possible links between headaches and other AEs after Covid-19 vaccination, thereby helping the management of AEs and avoiding further occurrences. METHODS: This study is based on a published questionnaire survey of 1,402 healthcare workers. Our study focused on the 5 questions including 12 AEs and headaches extracted from the questionnaire post the first and second Covid-19 vaccination. The severity of the 12 AEs and headaches could be classified by the participants on a five-step scale: "Not at all", "Little", "Average", "Quite", and "Very" (abbreviated as "N", "L", "A", "Q", "V"). We used the Bowker test to study the comparison of headache severity, indicated on a 5-point Likert scale between the first and second vaccinations. We applied an ordinal logistic regression to the 5 categories with headache severity serving as the dependent variable and the ratings of the other 12 AEs serving as the independent variable to further explore to what extent the severity of the 12 AEs is associated with the severity of headaches. Receiver Operating Characteristic (ROC) analysis was conducted to evaluate the predictive value of the ratings of the 12 AEs to headache severity. RESULTS: We found that participants rated their headaches as more severe after the second vaccination, and participants who reported experiencing fatigue, flu-like symptoms, pain at the injection site, known tension-type headache, fever, dizziness/balance problems and known migraine are associated with headache symptoms. CONCLUSIONS: There are clusters of headache-associated AEs post Covid-19 vaccination. The association of various AEs with headaches may be due to similar causative mechanisms.

Blood transcriptomics mirror regulatory mechanisms during hibernation-a comparative analysis of the Djungarian hamster with other mammalian species.

Hibernation enables many species of the mammalian kingdom to overcome periods of harsh environmental conditions. During this physically inactive state metabolic rate and body temperature are drastically downregulated, thereby reducing energy requirements (torpor) also over shorter time periods. Since blood cells reflect the organism´s current condition, it was suggested that transcriptomic alterations in blood cells mirror the torpor-associated physiological state. Transcriptomics on blood cells of torpid and non-torpid Djungarian hamsters and QIAGEN Ingenuity Pathway Analysis (IPA) revealed key target molecules (TMIPA), which were subjected to a comparative literature analysis on transcriptomic alterations during torpor/hibernation in other mammals. Gene expression similarities were identified in 148 TMIPA during torpor nadir among various organs and phylogenetically different mammalian species. Based on TMIPA, IPA network analyses corresponded with described inhibitions of basic cellular mechanisms and immune system-associated processes in torpid mammals. Moreover, protection against damage to the heart, kidney, and liver was deduced from this gene expression pattern in blood cells. This study shows that blood cell transcriptomics can reflect the general physiological state during torpor nadir. Furthermore, the understanding of molecular processes for torpor initiation and organ preservation may have beneficial implications for humans in extremely challenging environments, such as in medical intensive care units and in space.

Plasticity of the human IgM repertoire in response to long-term spaceflight.

Immune dysregulation is among the main adverse outcomes of spaceflight. Despite the crucial role of the antibody repertoire in host protection, the effects of spaceflight on the human antibody repertoire are unknown. Consequently, using high-throughput sequencing, we examined the IgM repertoire of five cosmonauts 25 days before launch, after 64 ± 11 and 129 ± 20 days spent on the International Space Station (ISS), and at 1, 7, and 30 days after landing. This is the first study of this kind in humans. Our data revealed that the IgM repertoire of the cosmonauts was different from that of control subjects (n = 4) prior to launch and that two out the five analyzed cosmonauts presented significant changes in their IgM repertoire during the mission. These modifications persisted up to 30 days after landing, likely affected the specificities of IgM binding sites, correlated with changes in the V(D)J recombination process responsible for creating antibody genes, and coincided with a higher stress response. These data confirm that the immune system of approximately half of the astronauts who spent 6 months on the ISS is sensitive to spaceflight conditions, and reveal individual responses indicating that personalized approaches should be implemented during future deep-space exploration missions that will be of unprecedented durations.

Propofol and Sevoflurane Differentially Impact MicroRNAs in Circulating Extracellular Vesicles during Colorectal Cancer Resection: A Pilot Study.

BACKGROUND: Extracellular vesicles and their microRNA cargo are crucial facilitators of malignant cell communication and could mediate effects of anesthetics on tumor biology during cancer resection. The authors performed a proof-of-concept study to demonstrate that propofol and sevoflurane have differential effects on vesicle-associated microRNAs that influence signaling pathways involved in tumor progression and metastasis. METHODS: Circulating vesicles were investigated in a prospective, matched-case pilot study in two cohorts of colorectal cancer patients receiving either propofol (n = 8) or sevoflurane (n = 9), matched for tumor stage and location. Serum was sampled before anesthesia and after tumor resection. Vesicular microRNA profiles were analyzed by next generation sequencing and confirmed by real-time polymerase chain reaction. Next, we assessed perioperative changes in microRNA expression induced by either anesthetic and compared their biologic effects on tumor-relevant pathways. Additionally, vesicles from pre- and postoperative sera were biologic characterized. RESULTS: Postoperative microRNA profiles were shifted in both groups with overlap in the perioperative response. A total of 64 (48 up, range of log2 fold change 1.07 to 3.76; 16 down, -1.00 to -1.55) and 33 (32 up, 1.02 to 2.98; 1 down, -1.36) microRNAs were significantly regulated (adjusted P value less than 0.05) by propofol and sevoflurane, respectively. Thirty-six (propofol) and five (sevoflurane) microRNAs were specifically responsive to either anesthetic agent. In silico target analyses of microRNA expression patterns indicated an inhibitory effect of propofol on crucial carcinoma-related pathways such as proliferation (z-score, -1.73) and migration (z-score, -1.97), as well as enhanced apoptosis (z-score, 1.19). While size distribution and protein markers of circulating vesicles were not affected by anesthesia, their concentration was reduced after surgery using both anesthetic procedures. CONCLUSIONS: This proof-of-concept study provides preliminary evidence that anesthetic agents have specific effects on microRNA profiles in circulating vesicles. These findings could form the basis for larger and mechanistically oriented outcome studies in cancer patients.

Exhaled Breath and Oxygenator Sweep Gas Propionaldehyde in Acute Respiratory Distress Syndrome.

BACKGROUND: Oxidative stress-induced lipid peroxidation (LPO) due to neutrophil-derived reactive oxygen species plays a key role in the early stage of the acute respiratory distress syndrome (ARDS). Monitoring of oxidative stress in this patient population is of great interest, and, ideally, this can be done noninvasively. Recently, propionaldehyde, a volatile chemical compound (VOC) released during LPO, was identified in the breath of lung transplant recipients as a marker of oxidative stress. The aim of the present study was to identify if markers of oxidative stress appear in the oxygenator outflow gas of patients with severe ARDS treated with veno-venous extracorporeal membrane oxygenation (ECMO). METHODS: The present study included patients with severe ARDS treated with veno-venous ECMO. Concentrations of acetone, isoprene, and propionaldehyde were measured in inspiratory air, exhaled breath, and oxygenator inflow and outflow gas at corresponding time points. Ion-molecule reaction mass spectrometry was used to measure VOCs in a sequential order within the first 24 h and on day three after ECMO initiation. RESULTS: Nine patients (5 female, 4 male; age = 42.1 ± 12.2 year) with ARDS and already established ECMO therapy (pre-ECMO PaO2/FiO2 = 44.0 ± 11.5 mmHg) were included into analysis. VOCs appeared in comparable amounts in breath and oxygenator outflow gas (acetone: 838 (422-7632) vs. 1114 (501-4916) ppbv; isoprene: 53.7 (19.5-244) vs. 48.7 (37.9-108) ppbv; propionaldehyde: 53.7 (32.1-82.2) vs. 42.9 (24.8-122) ppbv). Concentrations of acetone, isoprene, and propionaldehyde in breath and oxygenator outflow gas showed a parallel course with time. CONCLUSIONS: Acetone, isoprene, and propionaldehyde appear in breath and oxygenator outflow gas in comparable amounts. This allows for the measurement of these VOCs in a critically ill patient population via the ECMO oxygenator outflow gas without the need of ventilator circuit manipulation.

Immune sensitization during 1 year in the Antarctic high-altitude Concordia Environment.

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.

Oxidative burst and Dectin-1-triggered phagocytosis affected by norepinephrine and endocannabinoids: implications for fungal clearance under stress.

A prolonged stress burden is known to hamper the efficiency of both the innate and the adaptive immune systems and to attenuate the stress responses by the catecholaminergic and endocannabinoid (EC) systems. Key mechanisms of innate immunity are the eradication of pathogens through phagocytosis and the respiratory burst. We tested the concentration-dependent, spontaneous and stimulated (via TNFα and N-formylmethionine-leucyl-phenylalanine) release of reactive oxygen species (ROS) by human polymorphonuclear leukocytes (PMNs) in vitro in response to norepinephrine (NE) and AM1241, a pharmacological ligand for the EC receptor CB2. We evaluated phagocytosis of Dectin-1 ligating zymosan particles and tested the cytokine response against Candida antigen in an in vitro cytokine release assay. Increasing concentrations of NE did not affect phagocytosis, yet stimulated ROS release was attenuated gradually reaching maximum suppression at 500 nM. Adrenergic receptor (AR) mechanisms using non-AR-selective (labetalol) as well as specific α-(prazosin) and ß-(propranolol) receptor antagonists were tested. Results show that only labetalol and propranolol were able to recuperate cytotoxicity in the presence of NE, evidencing a ß-receptor-mediated effect. The CB2 agonist, AM1241, inhibited phagocytosis at 10 µM and spontaneous peroxide release by PMNs. Use of the inverse CB2 receptor agonist SR144528 led to partial recuperation of ROS production, confirming the functional role of CB2. Additionally, AM1241 delayed early activation of monocytes and induced suppression of IL-2 and IL-6 levels in response to Candida via lower activity of mammalian target of rapamycin (mTOR). These findings provide new insights into key mechanisms of innate immunity under stressful conditions where ligands to the sympatho-adrenergic and EC system are released.

Cellular and extracellular miRNAs are blood-compartment-specific diagnostic targets in sepsis.

Septic shock is a common medical condition with a mortality approaching 50% where early diagnosis and treatment are of particular importance for patient survival. Novel biomarkers that serve as prompt indicators of sepsis are urgently needed. High-throughput technologies assessing circulating microRNAs represent an important tool for biomarker identification, but the blood-compartment specificity of these miRNAs has not yet been investigated. We characterized miRNA profiles from serum exosomes, total serum and blood cells (leukocytes, erythrocytes, platelets) of sepsis patients by next-generation sequencing and RT-qPCR (n = 3 × 22) and established differences in miRNA expression between blood compartments. In silico analysis was used to identify compartment-specific signalling functions of differentially regulated miRNAs in sepsis-relevant pathways. In septic shock, a total of 77 and 103 miRNAs were down- and up-regulated, respectively. A majority of these regulated miRNAs (14 in serum, 32 in exosomes and 73 in blood cells) had not been previously associated with sepsis. We found a distinctly compartment-specific regulation of miRNAs between sepsis patients and healthy volunteers. Blood cellular miR-199b-5p was identified as a potential early indicator for sepsis and septic shock. miR-125b-5p and miR-26b-5p were uniquely regulated in exosomes and serum, respectively, while one miRNA (miR-27b-3p) was present in all three compartments. The expression of sepsis-associated miRNAs is compartment-specific. Exosome-derived miRNAs contribute significant information regarding sepsis diagnosis and survival prediction and could serve as newly identified targets for the development of novel sepsis biomarkers.

Hypoxia-induced and A2A adenosine receptor-independent T-cell suppression is short lived and easily reversible.

Tissue hypoxia plays a key role in establishing an immunosuppressive environment in vivo by, among other effects, increasing the level of extracellular adenosine, which then signals through A2A adenosine receptor (A2AR) to elicit its immunosuppressive effect. Although the important role of the adenosine--A2AR interaction in limiting inflammation has been established, the current study revisited this issue by asking whether hypoxia can also exert its T-cell inhibitory effects even without A2AR. A similar degree of hypoxia-triggered inhibition was observed in wild-type and A2AR-deficient T cells both in vitro and, after exposure of mice to a hypoxic atmosphere, in vivo. This A2AR-independent hypoxic T-cell suppression was qualitatively and mechanistically different from immunosuppression by A2AR stimulation. The A2AR-independent hypoxic immunosuppression strongly reduced T-cell proliferation, while IFN-γ-producing activity was more susceptible to the A2AR-dependent inhibition. In contrast to the sustained functional impairment after A2AR-mediated T-cell inhibition, the A2AR-independent inhibition under hypoxia was short lived, as evidenced by the quick recovery of IFN-γ-producing activity upon re-stimulation. These data support the view that T-cell inhibition by hypoxia can be mediated by multiple mechanisms and that both A2AR and key molecules in the A2AR-independent T-cell inhibition should be targeted to overcome the hypoxia-related immunosuppression in infected tissues and tumors.

Terrestrial stress analogs for spaceflight associated immune system dysregulation.

Recent data indicates that dysregulation of the immune system occurs and persists during spaceflight. Impairment of immunity, especially in conjunction with elevated radiation exposure and limited clinical care, may increase certain health risks during exploration-class deep space missions (i.e. to an asteroid or Mars). Research must thoroughly characterize immune dysregulation in astronauts to enable development of a monitoring strategy and validate any necessary countermeasures. Although the International Space Station affords an excellent platform for on-orbit research, access may be constrained by technical, logistical vehicle or funding limitations. Therefore, terrestrial spaceflight analogs will continue to serve as lower cost, easier access platforms to enable basic human physiology studies. Analog work can triage potential in-flight experiments and thus result in more focused on-orbit studies, enhancing overall research efficiency. Terrestrial space analogs generally replicate some of the physiological or psychological stress responses associated with spaceflight. These include the use of human test subjects in a laboratory setting (i.e. exercise, bed rest, confinement, circadian misalignment) and human remote deployment analogs (Antarctica winterover, undersea, etc.) that incorporate confinement, isolation, extreme environment, physiological mission stress and disrupted circadian rhythms. While bed rest has been used to examine the effects of physical deconditioning, radiation and microgravity may only be simulated in animal or microgravity cell culture (clinorotation) analogs. This article will characterize the array of terrestrial analogs for spaceflight immune dysregulation, the current evidence base for each, and interpret the analog catalog in the context of acute and chronic stress.

Postoperative hyperoxia (60%) worsens hepatic injury in mice.

BACKGROUND: Liver damage by ischemia and reperfusion injury is a risk factor for morbidity and mortality after liver surgery. Postoperative oxygen treatment is routinely applied in the postanesthesia and intensive care unit after liver surgery. The risks of aggravating the injury by increasing inspiratory oxygen from 21 to 60% in the postoperative period were investigated in mice. METHODS: Parameters of liver injury were compared after induction of hepatic ischemia-reperfusion injury, by clamping the left liver lobe for 45 min, and reperfusion for 24 h either under normoxic (21% oxygen) or hyperoxic (60% oxygen) conditions (n=22 per group). The extent of tissue injury and oxidative responses was analyzed in the presence or absence of polymorphonuclear leukocytes, functional Kupffer cells, and the p47phox unit of the nicotinamide adenine dinucleotide phosphate oxidase (n=6 to 11 per group). RESULTS: Compared with postoperative normoxic conditions, hyperoxia increased cell damage (glutamate-pyruvate transaminase: 1,870 [±968 SD] vs. 60% 2,981 [±1,038 SD], 21 vs. 60% oxygen, in U/l as mean±SD; P<0.01), liver weights (341±52 vs. 383±44, 21 vs. 60% oxygen, in mg as mean±SD; P=0.02), damage scores (1.9±0.8 vs. 3.1±1.0, 21 vs. 60% oxygen, score as mean±SD; P=0.02), and reactive oxygen species (15.0±12.0 vs. 30.4±19.2, 21 vs. 60% oxygen, in µmol/l as mean±SD; P<0.05). The aggravation of the tissue damaging effects as a result of hyperoxia was not seen in mice with depletions of polymorphonuclear leukocytes or Kupffer cells, or with nonfunctioning nicotinamide adenine dinucleotide phosphate oxidase. CONCLUSION: Liver injury after ischemia was significantly aggravated by hyperoxia as a consequence of immune cell-mediated oxidative burst. Further studies are needed to elucidate whether routine delivery of high inspirational oxygen concentrations postoperatively should be limited.

Differential effects of acute and chronic hydrocortisone treatment on pyroptosis.

Pyroptosis is a programmed and inflammation-inducing cell death that occurs predominantly in macrophages. It is characterized by the inflammasome-mediated activation of caspase-1, leading to cell lysis. During pyroptosis, pro-inflammatory mediators such as IL-1ß are released extracellularly to further recruit and activate other immune cells. Thus, pyroptosis plays a crucial role in the prevention of the spread of pathogens. The clinically applied synthetic glucocorticoid, hydrocortisone (HC), has strong immunoregulatory properties. It may act as an immunosuppressive agent by negatively regulating pro-inflammatory gene transcription but has also shown immune-sensitizing properties. The conditions that determine the immunosuppressive or immune-sensitizing actions of HC during an infection are not fully clear. We hypothesized that the outcome may differ depending on the onset and duration of its administration. Therefore, we investigated the impact of acute (treatment upon infection) and chronic (24 h pre-treatment before infection) HC treatment on pyroptosis induction and execution in THP-1 macrophage-like cells. The focus was on pyroptosis-associated signaling pathways, inflammasome assembly and activation, IL-1ß, and cell death. Physiological HC concentration and HC deprivation were used as controls. Compared to the physiological concentration, cells displayed augmented inflammasome activation and IL-1ß release following acute HC treatment. Conversely, the whole pyroptosis machinery was suppressed by chronic HC administration. These in vitro investigations demonstrate pro-inflammatory actions of acute HC exposure and the immunosuppressive effects of chronic treatment. These differential effects on pyroptosis emphasize the importance of individualized HC medication in patients upon infection, and suggest the inclusion of IL-1ß as a marker for current immune capacities.

Assessing Stress Induced by Fluid Shifts and Reduced Cerebral Clearance during Robotic-Assisted Laparoscopic Radical Prostatectomy under Trendelenburg Positioning (UroTreND Study).

In addition to general anesthesia and mechanical ventilation, robotic-assisted laparoscopic radical prostatectomy (RALP) necessitates maintaining a capnoperitoneum and placing the patient in a pronounced downward tilt (Trendelenburg position). While the effects of the resulting fluid shift on the cardiovascular system seem to be modest and well tolerated, the effects on the brain and the blood-brain barrier have not been thoroughly investigated. Previous studies indicated that select patients showed an increase in the optic nerve sheath diameter (ONSD), detected by ultrasound during RALP, which suggests an elevation in intracranial pressure. We hypothesize that the intraoperative fluid shift results in endothelial dysfunction and reduced cerebral clearance, potentially leading to transient neuronal damage. This prospective, monocentric, non-randomized, controlled clinical trial will compare RALP to conventional open radical prostatectomy (control group) in a total of 50 subjects. The primary endpoint will be the perioperative concentration of neurofilament light chain (NfL) in blood using single-molecule array (SiMoA) as a measure for neuronal damage. As secondary endpoints, various other markers for endothelial function, inflammation, and neuronal damage as well as the ONSD will be assessed. Perioperative stress will be evaluated by questionnaires and stress hormone levels in saliva samples. Furthermore, the subjects will participate in functional tests to evaluate neurocognitive function. Each subject will be followed up until discharge. Conclusion: This trial aims to expand current knowledge as well as to develop strategies for improved monitoring and higher safety of patients undergoing RALP. The trial was registered with the German Clinical Trials Register DRKS00031041 on 11 January 2023.

Palmer Station, Antarctica: A ground-based spaceflight analog suitable for validation of biomedical countermeasures for deep space missions.

Astronauts are known to exhibit a variety of immunological alterations during spaceflight including changes in leukocyte distribution and plasma cytokine concentrations, a reduction in T-cell function, and subclinical reactivation of latent herpesviruses. These alterations are most likely due to mission-associated stressors including circadian misalignment, microgravity, isolation, altered nutrition, and increased exposure to cosmic radiation. Some of these stressors may also occur in terrestrial situations. This study sought to determine if crewmembers performing winterover deployment at Palmer Station, Antarctica, displayed similar immune alterations. The larger goal was to validate a ground analog suitable for the evaluation of countermeasures designed to protect astronauts during future deep space missions. For this pilot study, plasma, saliva, hair, and health surveys were collected from Palmer Station, Antarctica, winterover participants at baseline, and at five winterover timepoints. Twenty-six subjects consented to participate over the course of two seasons. Initial sample processing was performed at Palmer, and eventually stabilized samples were returned to the Johnson Space Center for analysis. A white blood cell differential was performed (real time) using a fingerstick blood sample to determine alterations in basic leukocyte subsets throughout the winterover. Plasma and saliva samples were analyzed for 30 and 13 cytokines, respectively. Saliva was analyzed for cortisol concentration and three latent herpesviruses (DNA by qPCR), EBV, HSV1, and VZV. Voluntary surveys related to general health and adverse clinical events were distributed to participants. It is noteworthy that due to logistical constraints caused by COVID-19, the baseline samples for each season were collected in Punta Arenas, Chile, after long international travel and during isolation. Therefore, the Palmer pre-mission samples may not reflect a true normal 'baseline'. Minimal alterations were observed in leukocyte distribution during winterover. The mean percentage of monocyte concentration elevated at one timepoint. Plasma G-CSF, IL1RA, MCP-1, MIP-1ß, TNFα, and VEGF were decreased during at least one winterover timepoint, whereas RANTES was significantly increased. No statistically significant changes were observed in mean saliva cytokine concentrations. Salivary cortisol was substantially elevated throughout the entire winterover compared to baseline. Compared to shedding levels observed in healthy controls (23%), the percentage of participants who shed EBV was higher throughout all winterover timepoints (52-60%). Five subjects shed HSV1 during at least one timepoint throughout the season compared to no subjects shedding during pre-deployment. Finally, VZV reactivation, common in astronauts but exceptionally rare in ground-based stress analogs, was observed in one subject during pre-deployment and a different subject at WO2 and WO3. These pilot data, somewhat influenced by the COVID-19 pandemic, do suggest that participants at Palmer Station undergo immunological alterations similar to, but likely in reduced magnitude, as those observed in astronauts. We suggest that winterover at Palmer Station may be a suitable test analog for spaceflight biomedical countermeasures designed to mitigate clinical risks for deep space missions.

Endocannabinoids, endocannabinoid-like compounds and cortisone in head hair of health care workers as markers of stress and resilience during the early COVID-19 pandemic.

The pandemic caused by SARS-CoV-2 impacted health systems globally, creating increased workload and mental stress upon health care workers (HCW). During the first pandemic wave (March to May 2020) in southern Germany, we investigated the impact of stress and the resilience to stress in HCW by measuring changes in hair concentrations of endocannabinoids, endocannabinoid-like compounds and cortisone. HCW (n = 178) recruited from multiple occupation and worksites in the LMU-University-Hospital in Munich were interviewed at four interval visits to evaluate mental stress associated with the COVID-19 pandemic. A strand of hair of up to 6 cm in length was sampled once in May 2020, which enabled retrospective individual stress hormone quantifications during that aforementioned time period. Perceived anxiety and impact on mental health were demonstrated to be higher at the beginning of the COVID-19 pandemic and decreased significantly thereafter. Resilience was stable over time, but noted to be lower in women than in men. The concentrations of the endocannabinoid anandamide (AEA) and the structural congeners N-palmitoylethanolamide (PEA), N-oleoylethanolamide (OEA) and N-stearoylethanolamide (SEA) were noted to have decreased significantly over the course of the pandemic. In contrast, the endocannabinoid 2-arachidonoylglycerol (2-AG) levels increased significantly and were found to be higher in nurses, laboratory staff and hospital administration than in physicians. PEA was significantly higher in subjects with a higher resilience but lower in subjects with anxiety. SEA was also noted to be reduced in subjects with anxiety. Nurses had significantly higher cortisone levels than physicians, while female subjects had significant lower cortisone levels than males. Hair samples provided temporal and measurable objective psychophysiological-hormonal information. The hair endocannabinoids/endocannabinoid-like compounds and cortisone correlated to each other and to professions, age and sex quite differentially, relative to specific periods of the COVID-19 pandemic.

How to obtain an integrated picture of the molecular networks involved in adaptation to microgravity in different biological systems?

Periodically, the European Space Agency (ESA) updates scientific roadmaps in consultation with the scientific community. The ESA SciSpacE Science Community White Paper (SSCWP) 9, "Biology in Space and Analogue Environments", focusses in 5 main topic areas, aiming to address key community-identified knowledge gaps in Space Biology. Here we present one of the identified topic areas, which is also an unanswered question of life science research in Space: "How to Obtain an Integrated Picture of the Molecular Networks Involved in Adaptation to Microgravity in Different Biological Systems?" The manuscript reports the main gaps of knowledge which have been identified by the community in the above topic area as well as the approach the community indicates to address the gaps not yet bridged. Moreover, the relevance that these research activities might have for the space exploration programs and also for application in industrial and technological fields on Earth is briefly discussed.

How are cell and tissue structure and function influenced by gravity and what are the gravity perception mechanisms?

Progress in mechanobiology allowed us to better understand the important role of mechanical forces in the regulation of biological processes. Space research in the field of life sciences clearly showed that gravity plays a crucial role in biological processes. The space environment offers the unique opportunity to carry out experiments without gravity, helping us not only to understand the effects of gravitational alterations on biological systems but also the mechanisms underlying mechanoperception and cell/tissue response to mechanical and gravitational stresses. Despite the progress made so far, for future space exploration programs it is necessary to increase our knowledge on the mechanotransduction processes as well as on the molecular mechanisms underlying microgravity-induced cell and tissue alterations. This white paper reports the suggestions and recommendations of the SciSpacE Science Community for the elaboration of the section of the European Space Agency roadmap "Biology in Space and Analogue Environments" focusing on "How are cells and tissues influenced by gravity and what are the gravity perception mechanisms?" The knowledge gaps that prevent the Science Community from fully answering this question and the activities proposed to fill them are discussed.

Fructose protects murine hepatocytes from tumor necrosis factor-induced apoptosis by modulating JNK signaling.

Fructose-induced hepatic ATP depletion prevents TNF-induced apoptosis, whereas it contrarily enhances CD95-induced hepatocyte apoptosis in vitro and in vivo. By contrast, transformed liver cells are not protected against TNF due to metabolic alterations, allowing selective tumor targeting. We analyzed the molecular mechanisms by which fructose modulates cytokine-induced apoptosis. A release of adenosine after fructose-induced ATP depletion, followed by a cAMP response, was demonstrated. Likewise, cAMP and adenosine mimicked per se the modulation by fructose of CD95- and TNF-induced apoptosis. The effects of fructose on cytokine-induced apoptosis were sensitive to inhibition of protein kinase A. Fructose prevented the pro-apoptotic, sustained phase of TNF-induced JNK signaling and thereby blocked bid-mediated activation of the intrinsic mitochondrial apoptosis pathway in a PKA-dependent manner. We explain the dichotomal effects of fructose on CD95- and TNF-induced cell death by the selective requirement of JNK signaling for the latter. These findings provide a mechanistic rationale for the protection of hepatocytes from TNF-induced cell death by pharmacological doses of fructose.