Spatiotemporal expression and control of haemoglobin in space.

It is now widely recognised that the environment in space activates a diverse set of genes involved in regulating fundamental cellular pathways. This includes the activation of genes associated with blood homoeostasis and erythropoiesis, with a particular emphasis on those involved in globin chain production. Haemoglobin biology provides an intriguing model for studying space omics, as it has been extensively explored at multiple -omic levels, spanning DNA, RNA, and protein analyses, in both experimental and clinical contexts. In this study, we examined the developmental expression of haemoglobin over time and space using a unique suite of multi-omic datasets available on NASA GeneLab, from the NASA Twins Study, the JAXA CFE study, and the Inspiration4 mission. Our findings reveal significant variations in globin gene expression corresponding to the distinct spatiotemporal characteristics of the collected samples. This study sheds light on the dynamic nature of globin gene regulation in response to the space environment and provides valuable insights into the broader implications of space omics research.

Transcriptomic evidence of erythropoietic adaptation from the International Space Station and from an Earth-based space analog.

Space anemia affects astronauts and the underlying molecular alterations remain unknown. We evaluated the response of erythropoiesis-modulating genes to spaceflight through the analysis of leukocyte transcriptomes from astronauts during long-duration spaceflight and from an Earth model of microgravity. Differential expression analysis identified 50 genes encoding ribosomal proteins with reduced expression at the transition to bed rest and increased during the bed rest phase; a similar trend was observed in astronauts. Additional genes associated with anemia (15 genes), erythrocyte maturation (3 genes), and hemoglobin (6 genes) were down-regulated during bed rest and increased during reambulation. Transcript levels of the erythropoiesis transcription factor GATA1 and nine of most enriched erythrocyte proteins increased at reambulation after bed rest and at return to Earth from space. Dynamic changes of the leukocyte transcriptome composition while in microgravity and during reambulation supported an erythropoietic modulation accompanying the hemolysis of space anemia and of immobility-induced anemia.

Protecting the regenerative environment: selecting the optimal delivery vehicle for cartilage repair-a narrative review.

Focal cartilage defects are common in youth and older adults, cause significant morbidity and constitute a major risk factor for developing osteoarthritis (OA). OA is the most common musculoskeletal (MSK) disease worldwide, resulting in pain, stiffness, loss of function, and is currently irreversible. Research into the optimal regenerative approach and methods in the setting of either focal cartilage defects and/or OA holds to the ideal of resolving both diseases. The two fundamentals required for cartilage regenerative treatment are 1) the biological element contributing to the regeneration (e.g., direct application of stem cells, or of an exogenous secretome), and 2) the vehicle by which the biological element is suspended and delivered. The vehicle provides support to the regenerative process by providing a protective environment, a structure that allows cell adherence and migration, and a source of growth and regenerative factors that can activate and sustain regeneration. Models of cartilage diseases include osteochondral defect (OCD) (which usually involve one focal lesion), or OA (which involves a more diffuse articular cartilage loss). Given the differing nature of these models, the optimal regenerative strategy to treat different cartilage diseases may not be universal. This could potentially impact the translatability of a successful approach in one condition to that of the other. An analogy would be the repair of a pothole (OCD) versus repaving the entire road (OA). In this narrative review, we explore the existing literature evaluating cartilage regeneration approaches for OCD and OA in animal then in human studies and the vehicles used for each of these two conditions. We then highlight strengths and challenges faced by the different approaches presented and discuss what might constitute the optimal cartilage regenerative delivery vehicle for clinical cartilage regeneration.

The ups and downs of bone-marrow adipose tissue in space.

Knowledge is rapidly accumulating on basic roles and modulation of bone-marrow adipose tissue (BMAT). Among key modulators are physical forces on bones as exerted by gravity and exercise. Studying humans returning from space has revealed that, in addition to physical forces, local energetics within the bone marrow can play modulatory roles.

Association of Knee Osteoarthritis and Flexion Contracture With Localized Tibial Articular Cartilage Loss: Data From the Osteoarthritis Initiative.

OBJECTIVE: To evaluate whether a knee flexion contracture (FC) was associated with localized tibial articular cartilage loss over a 1-year period using Osteoarthritis Initiative quantitative data. METHODS: Five hundred seventy-eight participants from a previously established nested case-control study of people with radiographic knee OA with or without progression, based on radiographs and symptoms, had their knee range of extension measured at baseline and received magnetic resonance imaging (MRI) at baseline and 1 year. The tibial articular cartilage of the medial and lateral condyles was segmented into anterior, center, and posterior regions. We tested for associations between knee FC (defined as lack of extension to 0°), and localized changes in tibial articular cartilage thickness or percent of denuded bone (0 mm thickness) after 1 year relative to baseline using ANOVA, controlling for baseline MRI outcomes and clinical factors. RESULTS: Knee FC was associated with denuded bone in the medial condyle center (ß 0.44, 95% CI 0.02-0.86) and preserved cartilage thickness in the medial condyle posterior (ß 0.01, 95% CI 0.002-0.03) regions. CONCLUSION: Knee FC unloading the tibial center region and loading the posterior region was associated with localized articular cartilage loss centrally and preserved articular cartilage posteriorly. These findings are consistent with knee FC negatively affecting unloaded tibial articular cartilage.

Evidence- and data-driven classification of low back pain via artificial intelligence: Protocol of the PREDICT-LBP study.

In patients presenting with low back pain (LBP), once specific causes are excluded (fracture, infection, inflammatory arthritis, cancer, cauda equina and radiculopathy) many clinicians pose a diagnosis of non-specific LBP. Accordingly, current management of non-specific LBP is generic. There is a need for a classification of non-specific LBP that is both data- and evidence-based assessing multi-dimensional pain-related factors in a large sample size. The "PRedictive Evidence Driven Intelligent Classification Tool for Low Back Pain" (PREDICT-LBP) project is a prospective cross-sectional study which will compare 300 women and men with non-specific LBP (aged 18-55 years) with 100 matched referents without a history of LBP. Participants will be recruited from the general public and local medical facilities. Data will be collected on spinal tissue (intervertebral disc composition and morphology, vertebral fat fraction and paraspinal muscle size and composition via magnetic resonance imaging [MRI]), central nervous system adaptation (pain thresholds, temporal summation of pain, brain resting state functional connectivity, structural connectivity and regional volumes via MRI), psychosocial factors (e.g. depression, anxiety) and other musculoskeletal pain symptoms. Dimensionality reduction, cluster validation and fuzzy c-means clustering methods, classification models, and relevant sensitivity analyses, will classify non-specific LBP patients into sub-groups. This project represents a first personalised diagnostic approach to non-specific LBP, with potential for widespread uptake in clinical practice. This project will provide evidence to support clinical trials assessing specific treatments approaches for potential subgroups of patients with non-specific LBP. The classification tool may lead to better patient outcomes and reduction in economic costs.

Towards data-driven biopsychosocial classification of non-specific chronic low back pain: a pilot study.

The classification of non-specific chronic low back pain (CLBP) according to multidimensional data could guide clinical management; yet recent systematic reviews show this has not been attempted. This was a prospective cross-sectional study of participants with CLBP (n = 21) and age-, sex- and height-matched pain-free controls (n = 21). Nervous system, lumbar spinal tissue and psychosocial factors were collected. Dimensionality reduction was followed by fuzzy c-means clustering to determine sub-groups. Machine learning models (Support Vector Machine, k-Nearest Neighbour, Naïve Bayes and Random Forest) were used to determine the accuracy of classification to sub-groups. The primary analysis showed that four factors (cognitive function, depressive symptoms, general self-efficacy and anxiety symptoms) and two clusters (normal versus impaired psychosocial profiles) optimally classified participants. The error rates in classification models ranged from 4.2 to 14.2% when only CLBP patients were considered and increased to 24.2 to 37.5% when pain-free controls were added. This data-driven pilot study classified participants with CLBP into sub-groups, primarily based on psychosocial factors. This contributes to the literature as it was the first study to evaluate data-driven machine learning CLBP classification based on nervous system, lumbar spinal tissue and psychosocial factors. Future studies with larger sample sizes should validate these findings.

Bone marrow adiposity modulation after long duration spaceflight in astronauts.

Space travel requires metabolic adaptations from multiple systems. While vital to bone and blood production, human bone marrow adipose (BMA) tissue modulation in space is unknown. Here we show significant downregulation of the lumbar vertebrae BMA in 14 astronauts, 41 days after landing from six months' missions on the International Space Station. Spectral analyses indicated depletion of marrow adipose reserves. We then demonstrate enhanced erythropoiesis temporally related to low BMA. Next, we demonstrated systemic and then, local lumbar vertebrae bone anabolism temporally related to low BMA. These support the hypothesis that BMA is a preferential local energy source supplying the hypermetabolic bone marrow postflight, leading to its downregulation. A late postflight upregulation abolished the lower BMA of female astronauts and BMA modulation amplitude was higher in younger astronauts. The study design in the extreme environment of space can limit these conclusions. BMA modulation in astronauts can help explain observations on Earth.

The transcriptome response of astronaut leukocytes to long missions aboard the International Space Station reveals immune modulation.

Introduction: Spaceflight leads to the deconditioning of multiple body systems including the immune system. We sought to characterize the molecular response involved by capturing changes in leukocyte transcriptomes from astronauts transitioning to and from long-duration spaceflight. Methods: Fourteen male and female astronauts with ~6-month- long missions aboard the International Space Station (ISS) had 10 blood samples collected throughout the three phases of the study: one pre-flight (PF), four in-flight (IF) while onboard the ISS, and five upon return to Earth (R). We measured gene expression through RNA sequencing of leukocytes and applied generalized linear modeling to assess differential expression across all 10 time points followed by the analysis of selected time points and functional enrichment of changing genes to identify shifts in biological processes. Results: Our temporal analysis identified 276 differentially expressed transcripts grouped into two clusters (C) showing opposite profiles of expression with transitions to and from spaceflight: (C1) decrease-then-increase and (C2) increase-then-decrease. Both clusters converged toward average expression between ~2 and ~6 months in space. Further analysis of spaceflight transitions identified the decrease-then-increase pattern with most changes: 112 downregulated genes between PF and early spaceflight and 135 upregulated genes between late IF and R. Interestingly, 100 genes were both downregulated when reaching space and upregulated when landing on Earth. Functional enrichment at the transition to space related to immune suppression increased cell housekeeping functions and reduced cell proliferation. In contrast, egress to Earth is related to immune reactivation. Conclusion: The leukocytes' transcriptome changes describe rapid adaptations in response to entering space followed by opposite changes upon returning to Earth. These results shed light on immune modulation in space and highlight the major adaptive changes in cellular activity engaged to adapt to extreme environments.

Carbon monoxide as a clinical marker of hemolysis.

Carbon monoxide (CO)-based tests have precisely measured hemolysis for over 40 years. End-tidal CO was the primary marker in clinical hematology research, followed by carboxyhemoglobin. Quantification of CO reflects heme oxygenases degrading heme in a 1:1 stoichiometric ratio, making CO a direct marker of hemolysis. CO in alveolar air can be quantified using gas chromatography, whose high resolution allows detecting mild and moderate levels of hemolysis. CO can be elevated in active bleeding, resorbing hematoma, and smoking. Clinical acumen and other markers remain necessary to diagnose the cause of hemolysis. CO-based tests constitute an opportunity for bench-to-bedside technology transfer.

Asymmetric Flexion Contracture is Associated With Leg Length Inequality in Patients With Knee Osteoarthritis: Data From the Osteoarthritis Initiative.

OBJECTIVE: To evaluate whether knee flexion contracture (FC) was associated with leg length inequality (LLI) and/or morbidity in knee osteoarthritis (OA). DESIGN: We accessed 2 databases: (1) the Osteoarthritis Initiative (OAI) cohort, including participants with, or at-risk of OA, and (2) the Ottawa Knee Osteoarthritis cross-sectional database (OKOA), including participants with primary advanced knee OA. Both included demographics, radiographic data, knee range of motion, leg length, pain, and function scales. SETTING: Tertiary care academic rheumatology and orthopedic clinics. PARTICIPANTS: Patients with or at-risk of primary OA. We included 881 OAI and 72 OKOA participants (N=953). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: The primary outcome tested the association between the difference in knee extensions of the OA and contralateral knees (the knee extension difference, or KExD) and LLI. This was evaluated using bivariate regression, followed by a multivariable linear regression model. RESULTS: OAI participants had less severe knee OA [Kellgren and Lawrence (KL) score 1.9±1.3] vs OKOA (KL score 3.4±0.6). The KExD correlated with LLI for both databases (OAI: R=0.167; P≤.001; OKOA: R=0.339; P=.004). Multivariable regression showed an effect of KExD on LLI in both databases (OAI: ß=0.37[0.18,0.57]; P<.001, OKOA: ß=0.73[0.20,1.26]; P=.007). When broken down by subgroup, the OAI moderate-severe OA group showed a significant effect of KExD on LLI (ß=0.60 [0.34,0.85]; P<.001). CONCLUSIONS: OA-related loss of knee extension was associated with LLI for those with moderate-severe OA. Because LLI correlates with worse knee OA symptoms, discovering an FC should cue clinicians to evaluate for LLI, an easily-treatable finding that may help reduce OA-associated morbidity for those approaching the need for arthroplasty.

Adaptation and Validation of the Well-Being Related to Food Questionnaire (Well-BFQ©) for the French-Speaking General Adult Population of Québec, Canada.

Efforts to develop effective strategies that improve dietary intake are needed; however, this improvement in diet quality must not be at the expense of well-being. The Well-Being related to Food Questionnaire (Well-BFQ©) is a tool that has been developed in France to comprehensively measure food well-being. Even though the same language is spoken in France and in Québec, cultural and linguistic differences are present, which supports the importance of adapting and validating this tool before its use in the Québec population. This study aimed to adapt and validate the Well-BFQ© for the French-speaking general adult population of Québec, Canada. The Well-BFQ© underwent a full linguistic adaptation process, including an expert panel adaptation step, a pretest among 30 French-speaking adult (18-65 years) Quebecers, and a final proofreading. The questionnaire was thereafter administered to 203 French-speaking adult Quebecers (49.3% females, MAGE = 34.9, SD = 13.5; 88.2% Caucasians; 54.2% with a university degree). The exploratory factor analysis showed a two-factor structure: (1) food well-being related to physical and psychological health (27 items) and (2) food well-being related to symbolic/pleasure of food (32 items). Internal consistency was adequate, with a Cronbach's α of 0.92 and 0.93, respectively, for the subscales, and 0.94 for the total scale. The total food well-being score, as well as the two subscale scores, were associated with psychological and eating-related variables in expected directions. Overall, the adapted version of the Well-BFQ© was found to be a valid instrument to measure food well-being in the French-speaking general adult population of Québec, Canada.

The Characteristic Response of the Human Leukocyte Transcriptome to 60 Days of Bed Rest and to Reambulation.

INTRODUCTION: We sought to isolate the microgravity effect of spaceflight from other space stressors by characterizing the leukocytes' transcriptome of participants to a 60-d bed rest study; an Earth model of microgravity. METHODS: Twenty healthy men received a nutritional supplement or not and 10 blood samples were collected throughout three study phases: baseline data collection (BDC) (BDC-12, BDC-11), head-down tilt (HDT) bed rest (HDT1, HDT2, HDT30, HDT60), and reambulation (R1, R2, R12, R30). We measured gene expression through RNA sequencing of leukocytes, applied generalized linear models to assess differential expression followed by enrichment analysis to identify temporal changes (model 1) and to measure the impact of a nutritional supplement (model 2). RESULTS: Baseline transcriptomes included 14,624 protein-coding transcripts and showed both high intraindividual correlations (mean Kendall coefficient, 0.91 ± 0.04) and interindividual homogeneity (0.89 ± 0.03). We identified 2415 differentially expressed protein-coding transcripts grouping into six clusters (C1-C6). At phase transitions, clusters showed either a decrease-then-increase (C3 and C5) or an increase-then-decrease (C1, C2, C6) pattern. All six clusters converged toward average expression at HDT30 and HDT60. Gene ontology terms at baseline related to immune functions while in bed rest and reambulation related to sequestration of ions, immune response, cellular stress, and mineralization. The nutritional intervention had no effect. CONCLUSIONS: The temporal profiles of leukocytes' transcriptomes emphasized the dynamic nature of gene expression occurring during and after bed rest. Enriched biological processes among the differentially expressed genes included immune related and unrelated responses. The convergence toward no differential expression at days 30 and 60 of bed rest suggests a hypometabolic state. Current findings can guide future work on the complex responses and adaptation mechanisms to microgravity.

Baseline knee extension may be associated with volumetric cartilage loss in the anterolateral tibia: data from the Osteoarthritis Initiative.

OBJECTIVES: Animal studies suggest regional unloading of the knee due to flexion contracture (FC) results in cartilage loss in the anterior tibia. We looked for an association between the range of knee extension and articular cartilage thickness in the tibia of patients with knee OA, using quantitative MRI data from the OA Initiative. METHODS: Baseline knee extension was measured using a goniometer. Cartilage thickness was measured using 3-Tesla coronal MRI images of the knee. The tibia articular cartilage was segmented into medial and lateral regions, then further divided into anterior, central and posterior subregions. We evaluated differences between participants with and without a knee FC and associations between knee extension and cartilage thickness, including percentage denudation of bones (0 mm thickness), using linear models. RESULTS: A total of 596 participants were included. Participants with a knee FC had a larger percentage of denuded bone in the anterolateral tibia vs participants without FC (2.2 ± 0.7% vs 0.4 ± 0.1%; P = 0.006), and knee extension was associated with anterolateral tibia denuded bone (r = 0.16, P < 0.001). After correcting for demographics, knee alignment, and OA severity, presence of FC and lost knee extension were associated with the percentage of denuded bone in the anterolateral tibia [ß = 1.702 (0.634-2.770) and ß = 0.261 (95% CI 0.134, 0.388), respectively]. CONCLUSION: While causation cannot be determined in this study, limitation in knee extension was statistically associated with the percentage of denuded bone in the anterolateral tibia. These novel data support that maintaining range of motion over the entire joint surface may help preserve articular cartilage health.

Enhancing COVID Rehabilitation with Technology (ECORT): protocol for an open-label, single-site randomized controlled trial evaluating the effectiveness of electronic case management for individuals with persistent COVID-19 symptoms.

BACKGROUND: As of May 2022, Ontario has seen more than 1.3 million cases of COVID-19. While the majority of individuals will recover from infection within 4 weeks, a significant subset experience persistent and often debilitating symptoms, known as "post-COVID syndrome" or "Long COVID." Those with Long COVID experience a wide array of symptoms, with variable severity, including fatigue, cognitive impairment, and shortness of breath. Further, the prevalence and duration of Long COVID is not clear, nor is there evidence on the best course of rehabilitation for individuals to return to their desired level of function. Previous work with chronic conditions has suggested that the addition of electronic case management (ECM) may help to improve outcomes. These platforms provide enhanced connection with care providers, detailed symptom tracking and goal setting, and access to relevant resources. In this study, our primary aim is to determine if the addition of ECM with health coaching improves Long COVID outcomes at 3 months compared to health coaching alone. METHODS: The trial is an open-label, single-site, randomized controlled trial of ECM with health coaching (ECM+) compared to health coaching alone (HC). Both groups will continue to receive usual care. Participants will be randomized equally to receive health coaching (± ECM) for a period of 8 weeks and a 12-week follow-up. Our primary outcome is the WHO Disability Assessment Scale (WHODAS), 36-item self-report total score. Participants will also complete measures of cognition, fatigue, breathlessness, and mental health. Participants and care providers will be asked to complete a brief qualitative interview at the end of the study to evaluate acceptability and implementation of the intervention. DISCUSSION: There is currently little evidence about the optimal treatment of Long COVID patients or the use of digital health platforms in this population. The results of this trial could result in rapid, scalable, and personalized care for people with Long COVID which will decrease morbidity after an acute infection. Results from this study will also inform decision making in Long COVID and treatment guidelines at provincial and national levels. TRIAL REGISTRATION: ClinicalTrials.gov NCT05019963. Registered on 25 August 2021.

The Hunt Is On! In Pursuit of the Ideal Stem Cell Population for Cartilage Regeneration.

Cartilage injury and degeneration are hallmarks of osteoarthritis (OA), the most common joint disease. OA is a major contributor to pain, loss of function, and reduced quality of life. Over the last decade, considerable research efforts have focused on cell-based therapies, including several stem cell-derived approaches to reverse the cartilage alterations associated with OA. Although several tissue sources for deriving cell-based therapies have been identified, none of the resident stem cell populations have adequately fulfilled the promise of curing OA. Indeed, many cell products do not contain true stem cells. As well, issues with aggressive marketing efforts, combined with a lack of evidence regarding efficacy, lead the several national regulatory bodies to discontinue the use of stem cell therapy for OA until more robust evidence becomes available. A review of the evidence is timely to address the status of cell-based cartilage regeneration. The promise of stem cell therapy is not new and has been used successfully to treat non-arthritic diseases, such as hematopoietic and muscle disorders. These fields of regenerative therapy have the advantage of a considerable foundation of knowledge in the area of stem cell repair mechanisms, the role of the stem cell niche, and niche-supporting cells. This foundation is lacking in the field of cartilage repair. So, where should we look for the ideal stem cell to regenerate cartilage? It has recently been discovered that cartilage itself may contain a population of SC-like progenitors. Other potential tissues include stem cell-rich dental pulp and the adolescent growth plate, the latter of which contains chondrocyte progenitors essential for producing the cartilage scaffold needed for bone growth. In this article, we review the progress on stem cell therapies for arthritic disorders, focusing on the various stem cell populations previously used for cartilage regeneration, successful cases of stem cell therapies in muscle and hemopoietic disorders, some of the reasons why these other fields have been successful (i.e., "lessons learned" to be applied to OA stem cell therapy), and finally, novel potential sources of stem cells for regenerating damaged cartilage in vivo.

Hemolysis contributes to anemia during long-duration space flight.

Anemia in astronauts has been noted since the first space missions, but the mechanisms contributing to anemia in space flight have remained unclear. Here, we show that space flight is associated with persistently increased levels of products of hemoglobin degradation, carbon monoxide in alveolar air and iron in serum, in 14 astronauts throughout their 6-month missions onboard the International Space Station. One year after landing, erythrocytic effects persisted, including increased levels of hemolysis, reticulocytosis and hemoglobin. These findings suggest that the destruction of red blood cells, termed hemolysis, is a primary effect of microgravity in space flight and support the hypothesis that the anemia associated with space flight is a hemolytic condition that should be considered in the screening and monitoring of both astronauts and space tourists.

Exercise may impact on lumbar vertebrae marrow adipose tissue: Randomised controlled trial.

BACKGROUND: Animal and human cross-sectional data suggest that bone marrow adipose tissue (MAT) may respond to mechanical loads and exercise. We conducted the first randomised controlled trial of exercise on MAT modulations in humans. METHODS: Forty patients with chronic non-specific low back pain (NSCLBP) were enrolled in a six-month single-blinded randomised controlled trial (ACTRN12615001270505). Twenty patients loaded their spines via progressive upright aerobic and resistance exercises targeting major muscle groups (Exercise). Twenty patients performed non-weightbearing motor control training and manual therapy (Control). Testing occurred at baseline, 3-months (3mo) and 6-months (6mo). Lumbar vertebral fat fraction (VFF) was measured using magnetic resonance imaging axial mDixon sequences. RESULTS: When compared to baseline (percent change), lumbar vertebral fat fraction (VFF; measured using magnetic resonance imaging axial mDixon sequences) was lower in Exercise at 3mo at L2 (-3.7[6.8]%, p = 0.033) and L4 (-2.6[4.1]%, p = 0.015), but not in Control. There were no between-group effects. The effects of Exercise on VFF were sex-specific, with VFF lower in men at L2, L3, L4 at 3mo and at L1, L2, L3 and L4 at 6mo (p all ≤ 0.05), but not in women. Leg and trunk lean mass were increased at 3mo in Exercise. Changes in VFF correlated significantly with changes in total fat (ρ = 0.40) and lean (ρ = -0.41) masses, but not with lumbar BMD (ρ = -0.10) or visceral adipose tissue volume (ρ = 0.23). CONCLUSIONS: This trial provided first prospective evidence in humans that a moderate exercise intervention may modulate lumbar VFF as a surrogate measure of MAT at 3mo, yet not 6mo. The effect of exercise on MAT may be more prominent in males than females.