Effect of prebiotic fiber on physical function and gut microbiota in adults, mostly women, with knee osteoarthritis and obesity: a randomized controlled trial.

PURPOSE: Obesity is a primary risk factor for knee osteoarthritis (OA). Prebiotics enhance beneficial gut microbes and can reduce body fat and inflammation. Our objective was to examine if a 6-month prebiotic intervention improved physical function in adults with knee osteoarthritis and obesity. We also measured knee pain, body composition, quality of life, gut microbiota, inflammatory markers, and serum metabolomics. METHODS: Adults (n = 54, mostly women) with co-morbid obesity (BMI > 30 kg/m2) and unilateral/bilateral knee OA were randomly assigned to prebiotic (oligofructose-enriched inulin; 16 g/day; n = 31) or isocaloric placebo (maltodextrin; n = 21) for 6 months. Performance based-tests, knee pain, quality of life, serum metabolomics and inflammatory markers, and fecal microbiota and short-chain fatty acids were assessed. RESULTS: Significant between group differences were detected for the change in timed-up-and-go test, 40 m fast paced walk test, and hand grip strength test from baseline that favored prebiotic over placebo. Prebiotic also reduced trunk fat mass (kg) at 6 months and trunk fat (%) at 3 months compared to placebo. There was a trend (p = 0.059) for reduced knee pain at 6 months with prebiotic versus placebo. In gut microbiota analysis, a total of 37 amplicon sequence variants differed between groups. Bifidobacterium abundance was positively correlated with distance walked in the 6-min walk test and hand grip strength. At 6 months, there was a significant separation of serum metabolites between groups with upregulation of phenylalanine and tyrosine metabolism with prebiotic. CONCLUSION: Prebiotics may hold promise for conservative management of knee osteoarthritis in adults with obesity and larger trials are warranted. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov/study/NCT04172688.

The Heterogeneity of Post-Menopausal Disease Risk: Could the Basis for Why Only Subsets of Females Are Affected Be Due to a Reversible Epigenetic Modification System Associated with Puberty, Menstrual Cycles, Pregnancy and Lactation, and, Ultimately, Menopause?

For much of human evolution, the average lifespan was <40 years, due in part to disease, infant mortality, predators, food insecurity, and, for females, complications of childbirth. Thus, for much of evolution, many females did not reach the age of menopause (45-50 years of age) and it is mainly in the past several hundred years that the lifespan has been extended to >75 years, primarily due to public health advances, medical interventions, antibiotics, and nutrition. Therefore, the underlying biological mechanisms responsible for disease risk following menopause must have evolved during the complex processes leading to Homo sapiens to serve functions in the pre-menopausal state. Furthermore, as a primary function for the survival of the species is effective reproduction, it is likely that most of the advantages of having such post-menopausal risks relate to reproduction and the ability to address environmental stresses. This opinion/perspective will be discussed in the context of how such post-menopausal risks could enhance reproduction, with improved survival of offspring, and perhaps why such risks are preserved. Not all post-menopausal females exhibit risk for this set of diseases, and those who do develop such diseases do not have all of the conditions. The diseases of the post-menopausal state do not operate as a unified complex, but as independent variables, with the potential for some overlap. The how and why there would be such heterogeneity if the risk factors serve essential functions during the reproductive years is also discussed and the concept of sets of reversible epigenetic changes associated with puberty, pregnancy, and lactation is offered to explain the observations regarding the distribution of post-menopausal conditions and their potential roles in reproduction. While the involvement of an epigenetic system with a dynamic "modification-demodification-remodification" paradigm contributing to disease risk is a hypothesis at this point, validation of it could lead to a better understanding of post-menopausal disease risk in the context of reproduction with commonalities may also lead to future improved interventions to control such risk after menopause.

Optimizing tendon repair and regeneration: how does the in vivo environment shape outcomes following rupture of a tendon such as the Achilles tendon?

Risk for rupture of the Achilles tendon, and other tendons increases with age. Such injuries of tissues that function in high load environments generally are believed to heal with variable outcome. However, in many cases, the healing does not lead to a good outcome and the patient cannot return to the previous level of participation in active living activities, including sports. In the past few years, using proteomic approaches and other biological techniques, reports have appeared that identify biomarkers that are prognostic of good outcomes from healing, and others that are destined for poor outcomes using validated criteria at 1-year post injury. This review will discuss some of these recent findings and their potential implications for improving outcomes following connective tissue injuries, as well as implications for how clinical research and clinical trials may be conducted in the future where the goal is to assess the impact of specific interventions on the healing process, as well as focusing the emphasis on regeneration and not just repair.

'I do hope more people can benefit from it.': The qualitative experience of individuals living with osteoarthritis who participated in the GLA:D™ program in Alberta, Canada.

INTRODUCTION: The Good Life with osteoArthritis: Denmark (GLA:DTM) is an evidence-based program designed for individuals with symptomatic hip and knee osteoarthritis (OA). This program has reported improvement in pain, quality of life and self-efficacy, as well as delays in joint replacement surgery for adults with moderate to severe hip or knee OA. Evaluations of GLA:DTM implementation in several countries have focused on effectiveness, training, and feasibility of the program primarily from the provider perspective. Our objective was to examine how the GLA:DTM program was perceived and experienced by individuals with hip and knee OA to inform on-going program refinement and implementation. METHODS: Thirty semi-structured telephone interviews were conducted with participants who completed the GLA:DTM program in Alberta. An interpretive description approach was used to frame the study and thematic analysis was used to code the data and identify emergent themes and sub-themes associated with participants' experience and perception of the GLA:DTM program. RESULTS: Most participants had a positive experience of the GLA:DTM program and particularly enjoyed the group format, although some participants felt the group format prevented one-on-one support from providers. Three emergent themes related to acceptability were identified: accessible, adaptable, and supportive. Participants found the program to be accessible in terms of location, cost, and scheduling. They also felt the program was adaptable and allowed for individual attention and translatability into other settings. Finally, most participants found the group format to be motivating and fostered connections between participants. CONCLUSION: The GLA:DTM program was perceived as acceptable by most participants, yet the group format may not be useful for all individuals living with OA. Recommended improvements included adapting screening to identify those suited for the group format, providing program access earlier in the disease progression trajectory, modifying educational content based on participants' knowledge of OA and finally, providing refresher sessions after program completion.

Towards understanding how bisphosphonate-dependent alterations to nutrient canal integrity can contribute to risk for atypical femoral fractures: Biomechanical considerations and potential relationship to a real-world analogy.

Bisphosphonates are a class of drugs which have shown good efficacy in the treatment of post-menopausal osteoporosis, as well as a good safety profile. However, side-effects such as risk for atypical femoral fractures (AFF) have appeared, leading to a decline in use of the drugs by many patients who would benefit from the treatment. While patient characteristics have contributed to improved understanding of risk factors, the mechanisms involved that explain AFF risk have not appeared. Recently, the possibility that the mechanism(s) involved drug-induced modification of cells of the nutrient canals of the femur and subsequent compromise in the bone matrix has been published. The present Hypothesis article builds on the concept presented earlier and expands into biomechanical considerations. An analogy of the mechanisms involved to a real-life scenario is also presented. While this analogy has limitations, consideration of the biomechanical implications of progressive alterations to defects presented by compromised nutrient canal-bone matrix also presents potential relationships with AFF risk.

Repair of osteochondral defects: efficacy of a tissue-engineered hybrid implant containing both human MSC and human iPSC-cartilaginous particles.

Both mesenchymal stromal cells (MSC) and induced pluripotent stem cells (iPSC) offer the potential for repair of damaged connective tissues. The use of hybrid implants containing both human MSC and iPSC was investigated to assess their combined potential to yield enhanced repair of osteochondral defects. Human iPSC-CP wrapped with tissue engineered constructs (TEC) containing human MSC attained secure defect filling with good integration to adjacent tissue in a rat osteochondral injury model. The presence of living MSC in the hybrid implants was required for effective biphasic osteochondral repair. Thus, the TEC component of such hybrid implants serves several critical functions including, adhesion to the defect site via the matrix and facilitation of the repair via live MSC, as well as enhanced angiogenesis and neovascularization. Based on these encouraging studies, such hybrid implants may offer an effective future intervention for repair of complex osteochondral defects.

Complement factor D regulates collagen type I expression and fibroblast migration to enhance human tendon repair and healing outcomes.

Introduction: Dense connective tissues (DCTs) such as tendon, ligament, and cartilage are important stabilizers and force transmitters in the musculoskeletal system. The healing processes after DCT injuries are highly variable, often leading to degenerative changes and poor clinical outcome. Biomarkers in relation to repair quality for human DCTs, especially tendon are lacking. This study expands our previous findings and aimed to characterize the mechanisms by which a potential biomarker of good outcomes, complement factor D (CFD), regulates tendon healing. Methods: Quantitative mass spectrometry (QMS) profiling of tissue biopsies from the inflammatory phase of healing (n = 40 patients) and microdialysates from the proliferative phase of healing (n = 28 patients) were used to identify specific biomarkers for tendon healing. Further bioinformatic and experimental investigations based on primary fibroblasts and fibroblast cell line were used to confirm the identified biomarkers. Results: The QMS profiling of tissue biopsies from the inflammatory phase of healing identified 769 unique proteins, and microdialysates from the proliferative phase of healing identified 1423 unique proteins in Achilles tendon rupture patients. QMS-profiling showed that CFD expression was higher during the inflammatory- and lower during the proliferative healing phase in the good outcome patients. Further bioinformatic and experimental explorations based on both inflammatory and proliferative fibroblast models demonstrated that CFD potentially improved repair by regulating cell migration and modulating collagen type I (Col1a1) expression. Moreover, it was shown that the enhanced Col1a1 expression, through increased fibroblast migration, was correlated with the validated clinical outcome. Discussion: The results of the current studies characterized underlying inflammatory- and proliferative healing mechanisms by which CFD potentially improved tendon repair. These findings may lead to improved individualized treatment options, as well the development of effective therapies to promote good long-term clinical outcomes after tendon and other DCT injuries. Trial registration: http://clinicaltrials.gov, identifiers NCT02318472, NCT01317160.

Five-Year Outcomes After Implantation of a Scaffold-Free Tissue-Engineered Construct Generated From Autologous Synovial Mesenchymal Stromal Cells for Repair of Knee Chondral Lesions.

Background: In an earlier study, a scaffold-free tissue-engineered construct (TEC) derived from autologous synovial membrane mesenchymal stromal cells (MSCs) was developed and demonstrated to be safe and effective for cartilage repair at 2 years postoperatively. Purpose: To investigate clinical outcomes and magnetic resonance imaging (MRI) findings at 5 years after implantation. Study Design: Case series; Level of evidence, 4. Methods: This was an observational first-in-human study limited to 5 patients (age, 28-46 years) with symptomatic knee chondral lesions (size, 1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed at up to 5 years postoperatively. The patients were clinically evaluated using the visual analog scale for pain, Lysholm score, Tegner score, and Knee injury and Osteoarthritis Outcome Score. An MRI scan evaluation was also performed for morphologic and compositional quality of the repair tissue at both 2 and 5 years of follow-up. Results: All clinical scores were significantly improved from the preoperative evaluation to the 2- and 5-year follow-ups and the results were stable over time. The MRI scan evaluation showed cartilage defects filled with newly generated tissues with good tissue integration to adjacent host cartilage over time. The cartilage thickness and surface smoothness of the repair cartilage were maintained up to 5 years postoperatively. The MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 Knee Scores remained high at 5 years, although the total points decreased slightly. Conclusion: The results highlight the efficacy and feasibility of autologous scaffold-free TEC derived from synovial MSCs for regenerative cartilage repair via a sutureless and simple implantation procedure, showing good clinical outcomes and MRI findings with stable results at midterm follow-up. Further follow-up will be needed to assess the long-term quality of the repair tissue.

Physiological oxygen conditions enhance the angiogenic properties of extracellular vesicles from human mesenchymal stem cells.

BACKGROUND: Following an ischemic injury to the brain, the induction of angiogenesis is critical to neurological recovery. The angiogenic benefits of mesenchymal stem cells (MSCs) have been attributed at least in part to the actions of extracellular vesicles (EVs) that they secrete. EVs are membrane-bound vesicles that contain various angiogenic biomolecules capable of eliciting therapeutic responses and are of relevance in cerebral applications due to their ability to cross the blood-brain barrier (BBB). Though MSCs are commonly cultured under oxygen levels present in injected air, when MSCs are cultured under physiologically relevant oxygen conditions (2-9% O2), they have been found to secrete higher amounts of survival and angiogenic factors. There is a need to determine the effects of MSC-EVs in models of cerebral angiogenesis and whether those from MSCs cultured under physiological oxygen provide greater functional effects. METHODS: Human adipose-derived MSCs were grown in clinically relevant serum-free medium and exposed to either headspace oxygen concentrations of 18.4% O2 (normoxic) or 3% O2 (physioxic). EVs were isolated from MSC cultures by differential ultracentrifugation and characterized by their size, concentration of EV specific markers, and their angiogenic protein content. Their functional angiogenic effects were evaluated in vitro by their induction of cerebral microvascular endothelial cell (CMEC) proliferation, tube formation, and angiogenic and tight junction gene expressions. RESULTS: Compared to normoxic conditions, culturing MSCs under physioxic conditions increased their expression of angiogenic genes SDF1 and VEGF, and subsequently elevated VEGF-A content in the EV fraction. MSC-EVs demonstrated an ability to induce CMEC angiogenesis by promoting tube formation, with the EV fraction from physioxic cultures having the greatest effect. The physioxic EV fraction further upregulated the expression of CMEC angiogenic genes FGF2, HIF1, VEGF and TGFB1, as well as genes (OCLN and TJP1) involved in BBB maintenance. CONCLUSIONS: EVs from physioxic MSC cultures hold promise in the generation of a cell-free therapy to induce angiogenesis. Their positive angiogenic effect on cerebral microvascular endothelial cells demonstrates that they may have utility in treating ischemic cerebral conditions, where the induction of angiogenesis is critical to improving recovery and neurological function.

Implementing a guideline-based education and exercise program for people with knee and hip osteoarthritis-Practical experiences of providers and clinic leaders: A qualitative study.

BACKGROUND: The Good Life with osteoArthritis: Denmark (GLA:DTM ) program is an evidence-based education and exercise program designed for individuals with symptomatic hip and knee osteoarthritis. Launched in Denmark, it has been implemented across Europe, Australia, and North America. The authors assessed the feasibility of GLADTM implementation in Canada (Alberta) by applying the RE-AIM framework. An evaluation objective was to identify factors impacting the implementation of the program in both publicly funded and private rehabilitation settings, based on the experience of the initial cohort of providers and clinic leaders who set up and delivered the program. METHODS: Semi-structured telephone interviews were conducted with GLA:DTM -trained providers, managers, or directors of clinics across Alberta. Braun and Clarke's thematic approach was used to code the data and identify emergent categories and themes. Those relevant to the implementation were identified and by consensus, categorized as facilitators of and challenges to the implementation process. RESULTS: Eighteen GLA:DTM -trained providers and three clinic leaders from a range of clinical settings completed an interview. Seven common themes emerged in relation to implementation across the study settings. Three themes reflect facilitators of implementation (program acceptability by providers, multi-level support mechanisms, and program flexibility) and four implementation challenges (direct and indirect costs, lack of external referrals, program access issues, and lack of suitable space). The initial implementation of the program was exploratory with limited focus on long-term sustainability. CONCLUSIONS: The GLA:DTM program is a translatable program that can be implemented with relative ease in both public and private rehabilitation settings; however, costs, space constraints, and having an adequate referral base were noted challenges. Further work is warranted to explore equitable access across public and private settings and program sustainability.

Evaluation of Uveitis Induced in Rats by a Type I Collagen Peptide as a Model for Childhood Arthritis-associated Uveitis.

Chronic asymptomatic and acute symptomatic anterior uveitis are forms of ocular inflammation associated with juvenile idiopathic arthritis (JIA) Chronic JIA-associated uveitis is characterized by young age of onset, female predilection, oligoarthritis, and antinuclear antibody (ANA) positivity. Acute JIA-associated uveitis predominantly affects older male juveniles who also develop enthesitis. A type I collagen-derived peptide (melanin-associated antigen [MAA]) induces anterior uveitis in rodents. In this study, we evaluated MAA-induced uveitis in rats as a potential model for JIA-uveitis. We characterized MAA-induced uveitis by assessing its relationship to age and sex; tracking the occurrence of arthritis, enthesitis, and ANA positivity; and measuring vitreous fluid inflammatory biomarkers. Juvenile and adult and male and female Lewis rats (Rattus norvegicus) were inoculated with MAA. Slit-lamp biomicroscopy, indirect ophthalmoscopy, and joint examinations were performed 3 times weekly. Rats were euthanized at 4 wk after MAA inoculation, and plasma ANA testing, vitreous inflammatory biomarker assays, and globe histopathology assessments were conducted. Uveitis, arthritis, ANA status, levels of inflammatory biomarkers, histopathology, and joint tomographic images were assessed in relation to age and sex and compared with nonuveitic controls. All MAA-immunized rats developed uveitis characterized by anterior chamber fibrin, iridal vessel dilation, and miosis, and uveal and choroidal lymphocytic infiltration. Levels of the vitreous fluid biomarker CCL5 were higher in uveitic rats compared with control rats. Time to uveitis onset, clinical uveitis scores, and biomarker levels did not differ based on age or sex. None of the MAA-exposed rats had arthritis, enthesitis, or ANA. None of the rats inoculated with MAA that had been treated with matrix metallopeptidase 1 had clinical, histologic, or immunohistochemical evidence of ocular inflammation. In contrast to JIA-associated uveitis in humans, MAA-induced uveitis in rats is not associated with age or sex predilections and MAA is not arthritogenic.

The effect of geographic location and payor type on provincial-wide delivery of the GLA:D program for hip and knee osteoarthritis in Alberta, Canada.

Objective: The Good Life with osteoArthritis: Denmark (GLA:D™) program for knee and hip osteoarthritis has been shown to be effective, but evaluations have yet to explore whether effectiveness differs by program context. The present study explores whether there are differences in effectiveness of the GLA:D™ program for treatment of hip and knee osteoarthritis across program location (i.e., rural, urban, metro) and program payor (i.e., public, private) within Alberta, Canada. Design: The study population was adults with hip or knee osteoarthritis attending the 8-week GLA:D™ supervised exercise and education programme in Alberta between Sep 2017-Mar 2020. Outcomes of interest were joint-related pain and quality of life (HOOS/KOOS), health quality of life (EQ-5D-5L), and performance-based functional (30-s chair stand test; 40-m walk test) measures. Minimally clinically important changes were calculated for each outcome and ANOVA and chi-square tests were used to determine statistical significance by program location or payor. Results: Of the 1321 eligible participants, 974 (73.7%) completed the baseline questionnaire, about 50% of participants participated in a metro area and 60% paid privately for the program. There were no statistically significant differences in improvements of joint-related pain, joint-related quality of life, health-related quality of life, or performance-based functional measures by program location or program payor, except for participants who received the program in a publicly covered primary care clinic who experienced significantly larger improvements in joint-related pain. Conclusion: The implementation of the GLA:D™ program for the treatment of knee and hip osteoarthritis in Alberta is effective across a range of contexts.

Regulation of Bone by Mechanical Loading, Sex Hormones, and Nerves: Integration of Such Regulatory Complexity and Implications for Bone Loss during Space Flight and Post-Menopausal Osteoporosis.

During evolution, the development of bone was critical for many species to thrive and function in the boundary conditions of Earth. Furthermore, bone also became a storehouse for calcium that could be mobilized for reproductive purposes in mammals and other species. The critical nature of bone for both function and reproductive needs during evolution in the context of the boundary conditions of Earth has led to complex regulatory mechanisms that require integration for optimization of this tissue across the lifespan. Three important regulatory variables include mechanical loading, sex hormones, and innervation/neuroregulation. The importance of mechanical loading has been the target of much research as bone appears to subscribe to the "use it or lose it" paradigm. Furthermore, because of the importance of post-menopausal osteoporosis in the risk for fractures and loss of function, this aspect of bone regulation has also focused research on sex differences in bone regulation. The advent of space flight and exposure to microgravity has also led to renewed interest in this unique environment, which could not have been anticipated by evolution, to expose new insights into bone regulation. Finally, a body of evidence has also emerged indicating that the neuroregulation of bone is also central to maintaining function. However, there is still more that is needed to understand regarding how such variables are integrated across the lifespan to maintain function, particularly in a species that walks upright. This review will attempt to discuss these regulatory elements for bone integrity and propose how further study is needed to delineate the details to better understand how to improve treatments for those at risk for loss of bone integrity, such as in the post-menopausal state or during prolonged space flight.

Network proteomic analysis identifies inter-alpha-trypsin inhibitor heavy chain 4 during early human Achilles tendon healing as a prognostic biomarker of good long-term outcomes.

The suboptimal or protracted regeneration of injured connective tissues often results in significant dysfunction, pain, and functional disability. Despite the prevalence of the condition, few studies have been conducted which focused on biomarkers or key molecules involved in processes governing healing outcomes. To gain insight into injured connective tissue repair, and using the Achilles tendon as a model system, we utilized quantitative proteomic and weighted co-expression network analysis of tissues acquired from Achilles tendon rupture (ATR) patients with different outcomes at 1-year postoperatively. Two modules were detected to be associated with prognosis. The initial analysis identified inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) as a biomarker or hub protein positively associated with better healing outcomes. Additional analysis identified the beneficial role of ITIH4 in inflammation, cell viability, apoptosis, proliferation, wound healing, and for the synthesis of type I collagen in cultured fibroblasts. Functionally, the effects of ITIH4 were found to be mediated by peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathways. Taken together, these findings suggest that ITIH4 plays an important role in processes of connective tissue repair and advocate for the potential of ITIH4 as a therapeutic target for injured connective tissue repair. Trial registration: http://clinicaltrials.gov, identifiers NCT02318472, NCT01317160.

Alterations in skeletal muscle morphology and mechanics in juvenile male Sprague Dawley rats exposed to a high-fat high-sucrose diet.

Although once a health concern largely considered in adults, the obesity epidemic is now prevalent in pediatric populations. While detrimental effects on skeletal muscle function have been seen in adulthood, the effects of obesity on skeletal muscle function in childhood is not clearly understood. The purpose of this study was to determine if the consumption of a high-fat high-sucrose (HFS) diet, starting in the post-weaning period, leads to changes in skeletal muscle morphology and mechanics after 14 weeks on the HFS diet. Eighteen 3-week-old male CD-Sprague Dawley rats were randomly assigned to a HFS (C-HFS, n = 10) or standard chow diet (C-CHOW, n = 8). Outcome measures included: weekly energy intake, activity levels, oxygen consumption, body mass, body composition, metabolic profile, serum protein levels, and medial gastrocnemius gene expression, morphology, and mechanics. The main findings from this study were that C-HFS rats: (1) had a greater body mass and percent body fat than control rats; (2) showed early signs of metabolic syndrome; (3) demonstrated potential impairment in muscle remodeling; (4) produced lower relative muscle force; and (5) had a shift in the force-length relationship, indicating that the medial gastrocnemius had shorter muscle fiber lengths compared to those of C-CHOW rats. Based on the results of this study, we conclude that exposure to a HFS diet led to increased body mass, body fat percentage, and early signs of metabolic syndrome, resulting in functional deficits in MG of childhood rats.

Small extracellular vesicles derived from human adipose-derived mesenchymal stromal cells cultured in a new chemically-defined contaminate-free media exhibit enhanced biological and therapeutic effects on human chondrocytes in vitro and in a mouse osteoarthritis model.

Human small extracellular vesicles (sEVs) derived from adipose-derived mesenchymal stromal cells (ASC) have been reported to suppress the progression of osteoarthritis (OA) in animal studies and subsequently, translation of this potential to assess their clinical efficacy is anticipated. However, fabrication protocols for sEVs to eliminate potential contamination by culture medium-derived components need to be established prior to their clinical use. The purpose of the present studies was to elucidate the influence of medium-derived contaminants on the biological effects of sEVs, and to establish isolation methods for sEVs using a new clinical grade chemically-defined media (CDM). The quantity and purity of ASC-derived sEVs cultured in four different CDMs (CDM1, 2, 3 and 4) were evaluated. The concentrates of the four media incubated without cells were used as the background (BG) control for each set of sEVs. The biological effect of sEVs fabricated in the four different CDMs on normal human articular chondrocytes (hACs) were evaluated in vitro using a variety of methodological assessments. Finally, the sEVs with the highest purity were tested for their ability to suppress the progression of knee OA mouse model. Analysis of the BG controls revealed that CDM1-3 contained detectable particles, while there was no visible contamination of culture media-derived components detected with CDM4. Accordingly, the sEVs fabricated with CDM4 (CDM4-sEVs) exhibited the highest purity and yield. Notably, the CDM4-sEVs were the most efficient in promoting the cellular proliferation, migration, chondrogenic differentiation, and anti-apoptotic activity of hACs. Furthermore, CDM4-sEVs significantly suppressed the osteochondral degeneration in vivo model. Small EVs derived from ASCs cultured in a CDM without detectable contaminants demonstrated enhanced biological effects on hACs and the progression of OA. Thus, sEVs isolated with CDM4 most optimally meet the requirements of efficacy and safety for assessment in their future clinical applications.

eEF2 improves dense connective tissue repair and healing outcome by regulating cellular death, autophagy, apoptosis, proliferation and migration.

Outcomes following human dense connective tissue (DCT) repair are often variable and suboptimal, resulting in compromised function and development of chronic painful degenerative diseases. Moreover, biomarkers and mechanisms that guide good clinical outcomes after DCT injuries are mostly unknown. Here, we characterize the proteomic landscape of DCT repair following human Achilles tendon rupture and its association with long-term patient-reported outcomes. Moreover, the potential regulatory mechanisms of relevant biomarkers were assessed partly by gene silencing experiments. A mass-spectrometry based proteomic approach quantified a large number (769) of proteins, including 51 differentially expressed proteins among 20 good versus 20 poor outcome patients. A novel biomarker, elongation factor-2 (eEF2) was identified as being strongly prognostic of the 1-year clinical outcome. Further bioinformatic and experimental investigation revealed that eEF2 positively regulated autophagy, cell proliferation and migration, as well as reduced cell death and apoptosis, leading to improved DCT repair and outcomes. Findings of eEF2 as novel prognostic biomarker could pave the way for new targeted treatments to improve healing outcomes after DCT injuries.Trial registration: NCT02318472 registered 17 December 2014 and NCT01317160 registered 17 March 2011, with URL http://clinicaltrials.gov/ct2/show/NCT02318472 and http://clinicaltrials.gov/ct2/show/study/NCT01317160 .

Sex differences in musculoskeletal injury and disease risks across the lifespan: Are there unique subsets of females at higher risk than males for these conditions at distinct stages of the life cycle?

Sex differences have been reported for diseases of the musculoskeletal system (MSK) as well as the risk for injuries to tissues of the MSK system. For females, some of these occur prior to the onset of puberty, following the onset of puberty, and following the onset of menopause. Therefore, they can occur across the lifespan. While some conditions are related to immune dysfunction, others are associated with specific tissues of the MSK more directly. Based on this life spectrum of sex differences in both risk for injury and onset of diseases, a role for sex hormones in the initiation and progression of this risk is somewhat variable. Sex hormone receptor expression and functioning can also vary with life events such as the menstrual cycle in females, with different tissues being affected. Furthermore, some sex hormone receptors can affect gene expression independent of sex hormones and some transitional events such as puberty are accompanied by epigenetic alterations that can further lead to sex differences in MSK gene regulation. Some of the sex differences in injury risk and the post-menopausal disease risk may be "imprinted" in the genomes of females and males during development and sex hormones and their consequences only modulators of such risks later in life as the sex hormone milieu changes. The purpose of this review is to discuss some of the relevant conditions associated with sex differences in risks for loss of MSK tissue integrity across the lifespan, and further discuss several of the implications of their variable relationship with sex hormones, their receptors and life events.

Homo sapiens-A Species Not Designed for Space Flight: Health Risks in Low Earth Orbit and Beyond, Including Potential Risks When Traveling beyond the Geomagnetic Field of Earth.

Homo sapiens and their predecessors evolved in the context of the boundary conditions of Earth, including a 1 g gravity and a geomagnetic field (GMF). These variables, plus others, led to complex organisms that evolved under a defined set of conditions and define how humans will respond to space flight, a circumstance that could not have been anticipated by evolution. Over the past ~60 years, space flight and living in low Earth orbit (LEO) have revealed that astronauts are impacted to varying degrees by such new environments. In addition, it has been noted that astronauts are quite heterogeneous in their response patterns, indicating that such variation is either silent if one remained on Earth, or the heterogeneity unknowingly contributes to disease development during aging or in response to insults. With the planned mission to deep space, humans will now be exposed to further risks from radiation when traveling beyond the influence of the GMF, as well as other potential risks that are associated with the actual loss of the GMF on the astronauts, their microbiomes, and growing food sources. Experimental studies with model systems have revealed that hypogravity conditions can influence a variety biological and physiological systems, and thus the loss of the GMF may have unanticipated consequences to astronauts' systems, such as those that are electrical in nature (i.e., the cardiovascular system and central neural systems). As astronauts have been shown to be heterogeneous in their responses to LEO, they may require personalized countermeasures, while others may not be good candidates for deep-space missions if effective countermeasures cannot be developed for long-duration missions. This review will discuss several of the physiological and neural systems that are affected and how the emerging variables may influence astronaut health and functioning.

Are secondary effects of bisphosphonates on the vascular system of bone contributing to increased risk for atypical femoral fractures in osteoporosis?

Osteoporosis (OP) is a bone disease which affects a number of post-menopausal females and puts many at risk for fractures. A large number of patients are taking bisphosphonates (BPs) to treat their OP and a rare complication is the development of atypical femoral fractures (AFF). No real explanations for the mechanisms underlying the basis for development of where AFF develop while on BPs has emerged. The present hypothesis will discuss the possibility that part of the risk for an AFF is a secondary effect of BPs on a subset of vascular cells in a genetically at-risk population, leading to localized deregulation of the endothelial cell (EC)-bone cell-matrix units in nutrient channels/canals of the femur and increased risk for AFF. This concept of targeting ECs is consistent with location of AFF in the femur, the bilateral risk for occurrence of AFF, and the requirement for long term exposure to the drugs.