Morphology, mechanisms and pathology of musculoskeletal ageing

Ectodysplasin A2 receptor signaling in skeletal muscle pathophysiology

Skeletal muscle is essential in generating mechanical force and regulating energy metabolism and body temperature. Pathologies associated with muscle tissue often lead to impaired physical activity and imbalanced metabolism. Recently, ectodysplasin A2 receptor (EDA2R) signaling has been shown to promote muscle loss and glucose intolerance. Upregulated EDA2R expression in muscle tissue was associated with aging, denervation, cancer cachexia, and muscular dystrophies. Here, we describe the roles of EDA2R signaling in muscle pathophysiology, including muscle atrophy, insulin resistance, and aging-related sarcopenia. We also discuss the EDA2R pathway, which involves EDA-A2 as the ligand and nuclear factor (NF)κB-inducing kinase (NIK) as a downstream mediator, and the therapeutic potential of targeting these proteins in the treatment of muscle wasting and metabolic dysfunction.

Differential Effects of Endurance Exercise on Musculoskeletal and Hematopoietic Modulation in Old Mice

One of the most important strategies for successful aging is exercise. However, the effect of exercise can differ among individuals, even with exercise of the same type and intensity. Therefore, this study aims to confirm whether endurance training (ETR) has the same health-promoting effects on the musculoskeletal and hematopoietic systems regardless of age. Ten weeks of ETR improved endurance exercise capacity, with increased skeletal muscle mitochondrial enzymes in both young and old mice. In addition, age-related deterioration of muscle fiber size and bone microstructure was improved. The expression levels of myostatin, muscle RING-finger protein-1, and muscle atrophy F-box in skeletal muscle and peroxisome proliferator-activated receptor-γ in the femur increased with age but decreased after ETR. ETR differentially modulated hematopoietic stem cells (HSCs) depending on age; ETR induced HSC quiescence in young mice but caused HSC senescence in old mice. ETR has differential effects on modulation of the musculoskeletal and hematopoietic systems in old mice. In other words, endurance exercise is a double-edged sword for successful aging, and great effort is required to establish exercise strategies for healthy aging.

Prevalence and risk factors of work-related musculoskeletal disorders among shopkeepers in Ethiopia: Evidence from a workplace cross-sectional study

INTRODUCTION

Work-related musculoskeletal disorders (WRMSDs) are the leading cause of disability worldwide. Shopkeepers are prone to developing work-related musculoskeletal disorders, but they are largely overlooked in research and policy actions, particularly in developing countries. So far, there is a lack of data on the magnitude and factors influencing work-related musculoskeletal disorders among shopkeepers in Ethiopia. Therefore, the current study aimed to explore the prevalence and risk factors of work-related musculoskeletal disorders among shopkeepers in Gondar City, Ethiopia.

METHODS

A workplace-based cross-sectional study was conducted from July to August 2022, in Gondar city, Northwest Ethiopia. A multistage sampling technique was used to select 625 shopkeepers. The data were collected using an interviewer-administered standardized Nordic Musculoskeletal Questionnaire. Analysis was made using Stata version 14. Factors associated with the prevalence of work-related musculoskeletal disorders were identified using the multivariable Poisson regression model. The adjusted prevalence ratio with 95% confidence intervals (CIs) and p-value < 0.05 were applied to establish the significance of associations.

RESULTS

The overall prevalence of work-related musculoskeletal disorders among shopkeepers in the past 12 months was found to be 81.1% (N = 507). The most frequently affected body part was the lower back (46.6%), followed by the upper back (43.8%) and shoulder (35.4%). Being female (p = 0.043), being in the age group of ≥40 years (p = 0.028), being overweight (p = 0.035), experiencing job stress (p = 0.006) and prolonged sitting (p = 0.045) were significant factors for the prevalence of work-related musculoskeletal disorders among shopkeepers.

CONCLUSION

This study revealed that shopkeepers face an alarmingly high prevalence of work-related musculoskeletal disorders. Female, older, overweight, stressed and shopkeepers who sit in the same position for long periods of time were identified as particularly vulnerable groups. These findings call for the urgent development and implementation of preventive measures, including ergonomic adjustments, education and training programs, stress management techniques and the promotion of physical activity, to protect this vulnerable workforce from the debilitating effects of work-related musculoskeletal disorders and to ensure their long-term health and well-being.

Aging disrupts spatiotemporal regulation of germline stem cells and niche integrity

A major factor driving stem cell decline is stem cell niche aging, but its molecular mechanism remains elusive. We use the Caenorhabditis elegans distal tip cell (DTC), the mesenchymal niche that employs Notch signaling to regulate germline stem cells (GSCs), as an in vivo niche aging model and delineate the molecular details of the DTC/niche aging process. Here, we demonstrate that a drastic decrease in C. elegans germline fecundity, which begins even in early adulthood, is mainly due to an age-induced disruption in spatial regulation of Notch-dependent transcription in the germline combined with a moderate reduction in Notch transcription at both tissue and cellular levels. Consequently, the Notch-responsive GSC pool shifts from the distal end of the gonad to a more proximal region, disrupting the distal-to-proximal germline polarity. We find that this GSC pool shift is due to a dislocation of the DTC/niche nucleus, which is associated with age-induced changes in the structure and morphology of the DTC/niche. Our findings reveal a critical link between physiological changes in the aging niche, their consequences in stem cell regulation, and germline tissue functions.

Normal joint range of motion in children with Down syndrome

Down syndrome (DS) is one of the most common chromosomal conditions that results in intellectual disability. Children with DS have many different inflammatory and noninflammatory conditions that can affect joint mobility leading to arthralgia and altered joint range of motion (ROM), and it is important to have normal reference values for comparison to determine the degree of impairment. The objective of this study was to establish normative joint ROM values, using a standardized measurement approach, for upper and lower joints of healthy children of both genders with DS. This study evaluated joint ROM in healthy males and females with DS who had no previous musculoskeletal pathology. Younger males have more ROM than females at the same age and both genders lose ROM with age but continue to have increased ROM in the ankles compared to children without DS. This study establishes optimal estimates of joint ROM in children with DS, and this information should be helpful to clinicians when assessment requires evaluation of joint ROM to know if evaluation falls within the normal ROM. This reference should be helpful to track joint disease progression over time or as part of a musculoskeletal screen for abnormal joint ROM in children with DS.

A roadmap for delivering a human musculoskeletal cell atlas

Advances in single-cell technologies have transformed the ability to identify the individual cell types present within tissues and organs. The musculoskeletal bionetwork, part of the wider Human Cell Atlas project, aims to create a detailed map of the healthy musculoskeletal system at a single-cell resolution throughout tissue development and across the human lifespan, with complementary generation of data from diseased tissues. Given the prevalence of musculoskeletal disorders, this detailed reference dataset will be critical to understanding normal musculoskeletal function in growth, homeostasis and ageing. The endeavour will also help to identify the cellular basis for disease and lay the foundations for novel therapeutic approaches to treating diseases of the joints, soft tissues and bone. Here, we present a Roadmap delineating the critical steps required to construct the first draft of a human musculoskeletal cell atlas. We describe the key challenges involved in mapping the extracellular matrix-rich, but cell-poor, tissues of the musculoskeletal system, outline early milestones that have been achieved and describe the vision and directions for a comprehensive musculoskeletal cell atlas. By embracing cutting-edge technologies, integrating diverse datasets and fostering international collaborations, this endeavour has the potential to drive transformative changes in musculoskeletal medicine.

Multiparity and Aging Impact Chondrogenic and Osteogenic Potential at Symphyseal Enthesis: New Insights into Interpubic Joint Remodeling

Pregnancy and childbirth cause adaptations to the birth canal to allow for delivery and fast recovery. To accommodate delivery through the birth canal, the pubic symphysis undergoes changes that lead to the interpubic ligament (IpL) and enthesis formation in primiparous mice. However, successive deliveries influence joint recovery. We aimed to understand tissue morphology and chondrogenic and osteogenic potential at symphyseal enthesis during pregnancy and postpartum in primiparous and multiparous senescent female mice. Morphological and molecular differences were found at the symphyseal enthesis among the study groups. Despite the apparent incapacity to restore cartilage in multiparous senescent animals, the symphyseal enthesis cells are active. However, these cells have reduced expression of chondrogenic and osteogenic markers and are immersed in densely packed collagen fibers contiguous to the persistent IpL. These findings may indicate alterations of key molecules in the progenitor cell population maintenance of the chondrocytic and osteogenic lineages at the symphyseal enthesis in multiparous senescent animals, possibly compromising the mouse joint histoarchitecture recovery. This sheds light on the distention of the birth canal and the pelvic floor that may play a role in pubic symphysis diastasis (PSD) and pelvic organ prolapse (POP), both in orthopedic and urogynecological practice in women.

Characteristics of Postoperative Patients with Breast Cancer Aged 65 Years and Older

Objective: This study aimed to compare postoperative patients with breast cancer aged ≥65 years with those aged <65 years and clarify the characteristics of postoperative patients with breast cancer aged ≥65. Methods: In total, 376 patients in whom we were able to evaluate survey items one month after surgery were included in the study. Comorbidity, including diabetes mellitus and hypertension, shoulder range of motion (ROM), upper-limb function, and psychological problems, was evaluated. Results: Hypertension and diabetes mellitus were significantly higher in patients aged ≥65 years (the elderly group) than in those aged <65 years (the non-elderly group) (p < 0.05). Preoperative shoulder flexion ROM was significantly restricted in the elderly group compared with the non-elderly group (p < 0.05). Preoperative shoulder abduction ROM was significantly restricted in the elderly group compared with the non-elderly group (p < 0.05). At one month after surgery, upper-limb function was more impaired in the non-elderly group than in the elderly group (p < 0.05). In both groups, both ROM and upper-limb function were significantly impaired one month after surgery compared with before surgery (p < 0.05). Conclusions: Postoperative patients with breast cancer aged ≥65 years should be careful about risk management and intervention during rehabilitation. Preoperative evaluation of shoulder ROM should be performed because patients aged ≥65 years have limited ROM before surgery.

Musculoskeletal Disorder Burden and Its Attributable Risk Factors in China: Estimates and Predicts from 1990 to 2044

Musculoskeletal disorders are one of the three major disabling diseases in the world. However, the current disease burden in China is not well-known. This study aimed to explore the burden and risk factors of musculoskeletal disorders in China from 1990 to 2019, predicting the incidence trend from 2020 to 2044. All data were extracted from the Global Burden of Disease Study 2019 (GBD 2019). Joinpoint regression and age-period-cohort (APC) models were selected to analyze the epidemic trend, and descriptive analyses of the time trends and age distributions of risk factors were performed. The Bayesian APC model was used to foresee the incidence trend from 2020 to 2044. The results indicated that the burden of musculoskeletal disorders is higher in women and older adults. Its attributable risk factors were found to be tobacco, a high body mass index, kidney dysfunction and occupational risks. In 2044, musculoskeletal disorders in China showed a downward trend for 35-59-year-olds and a slight upward trend for 30-34- and 65-84-year-olds. The 70-74 year age group saw the largest increase in incidence at 4.66%. Overall, the incidence increased with age. Therefore, prevention and control policies should focus on women and the elderly, and health interventions should be carried out based on risk factors.

mtDNA variability determines spontaneous joint aging damage in a conplastic mouse model

Mitochondria and mtDNA variations contribute to specific aspects of the aging process. Here, we aimed to investigate the influence of mtDNA variation on joint damage in a model of aging using conplastic mice. A conplastic (BL/6^NZB) mouse strain was developed with the C57BL/6JOlaHsd nuclear genome and NZB/OlaHsd mtDNA, for comparison with the original C57BL/6JOlaHsd strain (BL/6^C57). Conplastic (BL/6^NZB) and BL/6^C57 mice were sacrificed at 25, 75, and 90 weeks of age. Hind knee joints were processed for histological analysis and joint pathology graded using the Mankin scoring system. By immunohistochemistry, cartilage expression of markers of autophagy (LC3, Beclin-1, and P62) and markers of senescence (MMP13, beta-Galactosidase, and p16) and proliferation (Ki67) were analyzed. We also measured the expression of 8-oxo-dG and cleaved caspase-3.

Conplastic (BL/6^NZB) mice presented lower Mankin scores at 25, 75, and 90 weeks of age, higher expression of LC3 and Beclin-1 and lower of P62 in cartilage than the original strain. Moreover, the downregulation of MMP13, beta-Galactosidase, and p16 was detected in cartilage from conplastic (BL/6^NZB) mice, whereas higher Ki67 levels were detected in these mice. Finally, control BL/6^C57 mice showed higher cartilage expression of 8-oxo-dG and cleaved caspase-3 than conplastic (BL/6^NZB) mice. This study demonstrates that mtDNA genetic manipulation ameliorates joint aging damage in a conplastic mouse model, suggesting that mtDNA variability is a prognostic factor for aging-related osteoarthritis (OA) and that modulation of mitochondrial oxidative phosphorylation (OXPHOS) could be a novel therapeutic target for treating OA associated with aging.

Molecular Mechanisms of Changes in Homeostasis of the Dermal Extracellular Matrix: Both Involutional and Mediated by Ultraviolet Radiation

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. With age, an impairment of structures, quality characteristics, and functions of the dermal extracellular matrix (ECM) occurs in the skin, which leads to disrupted functioning of dermal fibroblasts (DFs), the main cells supporting morphofunctional organization of the skin. The DF functioning directly depends on the state of the surrounding collagen matrix (CM). The intact collagen matrix ensures proper adhesion and mechanical tension in DFs, which allows these cells to maintain collagen homeostasis while ECM correctly regulates cellular processes. When the integrity of CM is destroyed, mechanotransduction is disrupted, which is accompanied by impairment of DF functioning and destruction of collagen homeostasis, thereby contributing to the progression of aging processes in skin tissues. This article considers in detail the processes of skin aging and associated changes in the skin layers, as well as the mechanisms of these processes at the molecular level.

Association Between the Amount of Limb Lengthening and Hip Range of Motion After Total Hip Arthroplasty

AIMS

The relationship between prosthetic position and range of motion (ROM) after total hip arthroplasty (THA) has been rigorously examined. However, the effects of limb lengthening on postoperative hip ROM remain unclarified. We aimed to examine the effect of limb lengthening on hip ROM after THA.

METHODS

We retrospectively reviewed the data from 120 patients who underwent unilateral THA. Univariate and multivariate regression models were used to evaluate the effects of the following patient- and surgery-related covariates on hip flexion ROM at 3, 6, and 12 months after THA: age, sex, body mass index, diagnosis, preoperative University of California Los Angeles activity score, preoperative Oxford Hip Score, preoperative flexion ROM, amount of leg lengthening, cup inclination, and cup anteversion.

RESULTS

A large preoperative hip flexion ROM was the strongest predictor of a large hip flexion ROM at 12 months after THA (standardized coefficient: 0.519, P < 0.0001). A larger amount of leg lengthening was associated with a smaller postoperative hip flexion ROM (standardized coefficient: -0.159, P = 0.039), and male sex was another predictor of a smaller postoperative hip flexion ROM (standardized coefficient: -0.204, P = 0.014). Cup inclination (P = 0.99) and anteversion (P = 0.18) were not significantly associated with hip flexion ROM at 12 months after THA.

DISCUSSION

A large amount of limb lengthening was associated with decreased hip flexion ROM after THA. In THA, minimizing the leg length discrepancy is important; however, the postoperative improvement in hip flexion ROM may be limited when a large amount of leg lengthening is needed.

Discrepancy in the Responsiveness to Hip Range of Motion Between Harris and Oxford Hip Scores

Background

The primary objectives of total hip arthroplasty (THA) include mobility improvement and pain relief; however, the correlation between hip range of motion (ROM) and function remains unclear. We aimed to explore how ROM affects hip functions after THA and compare the responsiveness of each component of the modified Harris Hip Score (mHHS) and Oxford Hip Score (OHS) to preoperative and postoperative ROM.

Methods

This prospective observational study involved 120 patients who underwent unilateral THA. Univariate regression analyses were performed using the University of California Los Angeles activity score and mHHS and OHS to determine the effects of preoperative and postoperative flex ROM on clinical scores at 12 months. Multivariate regressions were performed to adjust for the confounding effects of patient factors: age, sex, body mass index, and diagnosis.

Results

A larger preoperative flexion ROM was associated with a higher score in the mHHS socks component (standardized coefficient [SC] = 0.26, P = .0041) at 12 months; the effect on the OHS socks component was not significant (P = .34). A larger flexion ROM at 12 months was associated with higher scores in the mHHS support (SC = 0.21, P = .026), stairs (SC = 0.35, P = .0002), and socks (SC = 0.32, P = .0007) components but had no significant effect on any OHS component. The effects of ROM on University of California Los Angeles activity score were limited.

Conclusions

A discrepancy was noted in the responsiveness to ROM between the two major measurement tools; this difference might be because mHHS and OHS are surgeon- and patient-administered questionnaires, respectively. This discrepancy also suggests that the patients have higher satisfaction than that assumed by the surgeons.

Motor Unit Fatigability following Chronic Carnosine Supplementation in Aged Rats

Studies suggest that carnosine (beta-alanyl-L-histidine) is effective in treating neuromuscular diseases associated with aging, but there is still a need to clarify its role in motor units (MUs) function during aging. In this study, 40 male Wistar rats aged 15 months were randomly assigned to a control or to two experimental groups in which 0.1% carnosine supplementation was performed for 10 or 34 weeks. After 34 weeks, we examined fast fatigable (FF), fast fatigue-resistant (FR) and slow (S) MUs’ force properties and fatigability, as well as antioxidant potential, advanced glycation end products, activity of enzymes, and histidyl dipeptides content in the medial gastrocnemius muscle. Short- and long-term carnosine supplementation maintained the force of FF MUs at a higher level during its rapid decline seen from the initial 10 to 70 s of the fatigue test. In FF, especially long-term, and in FR MUs, especially short-term, carnosine supplementation resulted in less rapid force decline during the initial 70 s of the second fatigue protocol. Carnosine supplementation did not change muscle antioxidant potential and mortality rate (~35% in all groups), nor muscle mass with aging. Moreover, instead of the expected increase, a decrease in histidyl dipeptides by ~30% in the red portion of medial gastrocnemius muscle after long-term supplementation was found. After chronic carnosine supplementation, the specific changes in fatigue resistance were observed in FF and FR units, but not in S MU types that were not accompanied by an improvement of antioxidant potential and activity of glycolytic or oxidative enzymes in aged rats. These observations indicate that carnosine supplementation during aging may generate different physiological adaptations which should be considered as an important factor when planning treatment strategies.

An integrated approach to investigate age-related modifications of morphological, mechanical and structural properties of type I collagen

The main propose of this study is to characterize the impact of chronological aging on mechanical, structural, biochemical, and morphological properties of type I collagen. We have developed an original approach combining a stress-strain measurement device with a portable Raman spectrometer to enable simultaneous measurement of Raman spectra during stress vs strain responses of young adult, adult and old rat tail tendon fascicles (RTTFs). Our data showed an increase in all mechanical properties such as Young's modulus, yield strength, and ultimate tensile strength with aging. At the molecular level, Raman data revealed that the most relevant frequency shift was observed at 938 cm^-1 in Old RTTFs, which is assigned to the C-C. This suggested a long axis deformation of the peptide chains in Old RTTFs during tensile stress. In addition, the intensity of the band at 872 cm^-1, corresponding to hydroxyproline decreased for young adult RTTFs and increased for the adult ones, while it remained unchanged for Old RTTFs during tensile stress. The amide III band (1242 and 1265 cm^-1) as well as the band ratios I₁₆₃₁/ I₁₆₆₃ and I₁₆₄₅ / I₁₆₆₃ responses to tensile stress were depending on mechanical phases (toe, elastic and plastic). The quantification of advanced glycation end-products by LC-MS/MS and spectrofluorometry showed an increase in their content with aging. This suggested that the accumulation of such products was correlated to the alterations observed in the mechanical and molecular properties of RTTFs. Analysis of the morphological properties of RTTFs by SHG combined with CT-FIRE software revealed an increase in length and straightness of collagen fibers, whereas their width and wavy fraction decreased. Our integrated study model could be useful to provide additional translational information to monitor progression of diseases related to collagen remodeling in musculoskeletal disorders. STATEMENT OF SIGNIFICANCE: Type I collagen is the major component of the extracellular matrix. Its architectural and structural organization plays an important role in the mechanical properties of many tissues at the physiological and pathological levels. The objective of this work is to develop an integrated approach to bring a new insight on the impact of chronological aging on the structural organization and mechanical properties of type I collagen. We combined a portable Raman spectrometer with a mechanical tensile testing device in order to monitor in real time the changes in the Raman fingerprint of type I collagen fibers during the mechanical stress. Raman spectroscopy allowed the identification of the type I collagen bonds that were affected by mechanical stress in a differential manner with aging.

Virtual reality-based cognitive stimulation using GRYDSEN software as a means to prevent age-related cognitive-mobility disorders – a pilot observational study

The human aging process is associated with systematic deterioration of cognitive and motor performance. Age-related deficits in motor skills and symptoms of cognitive decline, such as memory, attention and executive functioning problems, are major contributors to a loss of functional independence and reduced quality of life of the elderly. The virtual reality system presented can be used as an aid for effective training of those skills. The use of virtual reality training for therapeutic purposes is promising – not only does it provide encouraging medical and psychological effects but it may also be considered as an interesting leisure activity for seniors. The paper presents a pilot study which aims to qualitatively assess the usefulness of a VR technology-based solution for training cognitive and motor functions. The pre-test phase of the study was conducted on 9 subjects aged 62-81 (M = 71.66; SD = 7.00), who were asked to evaluate the performed tasks in terms of novelty and attractiveness. All subjects completed the pilot study. The SUS result was 55.56 (SD = 9.90), which is a marginal result. However, the UEQ result showed that all aspects of the game were reported as satisfactory. The pilot studies show that VR is well tolerated by the elderly. As demonstrated by the results, the system has moderate utility, but may be a promising solution for training cognitive-motor skills.

Evaluation of musculoskeletal adverse effects in patients on systemic isotretinoin treatment: A cross-sectional study

Objectives

This study aims to investigate the frequency of musculoskeletal adverse effects in acne vulgaris patients receiving systemic isotretinoin treatment.

Patients and methods

Between January 2016 and December 2017, a total of 200 severe acne patients (22 males, 178 females; mean age: 21.8±0.4 years; range, 15 to 53 years) who were on isotretinoin treatment were retrospectively analyzed. Data including age, sex, body mass index (BMI), duration of disease, diagnosis, and comorbidities were recorded. Back pain severity was evaluated with the Visual Analog Scale (VAS).

Results

The treatment period was mean 8.5±0.1 (range, 6 to 12) months. The dose of isotretinoin was mean 0.6±0.1 (range, 0.5 and 1) mg/kg. Musculoskeletal side effects were seen in 99 (49.5%) patients. Back pain was reported during the treatment period in 78 (78.7%) patients. The diagnosis was mechanical back pain in 31 (39.7%) and inflammatory back pain in 47 (60.3%) patients. The moderate-severe back pain group received higher cumulative isotretinoin doses than the mild back pain group (p=0.003). The BMI values did not show a significant difference between the patients with and without back pain (p=0.55). There was no significant correlation between the BMI and VAS scores (p=0.06). The VAS scores were found to be correlated with age (p=0.04). Sacroiliitis was diagnosed in four (4%) patients. One (1%) patient was diagnosed with enthesitis. Creatine kinase elevation was reported in 18 (18.1%) patients, while three (3%) patients described myalgia of mild severity.

Conclusion

Low back pain is one of the most common musculoskeletal side effects of isotretinoin treatment that usually resolves with dose reduction. The cumulative dose of isotretinoin does not seem to play a role in the development of back pain, but can determine pain severity. Pain severity is directly correlated with the increasing age. Evaluation of the patients for musculoskeletal side effects during isotretinoin use is important in clinical practice, as it is a common occurrence.

The Role of Hypertension in Cartilage Restoration: Increased Failure Rate After Autologous Chondrocyte Implantation but Not After Osteochondral Allograft Transplantation

Objectives. The purpose of this study was to examine whether patients with diagnosed hypertension have an increased risk of graft failure following cartilage repair with either autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA). We hypothesized that hypertension is related to higher ACI and OCA graft failure. Design. Patients who underwent ACI or OCA transplantation between February 2009 and December 2016 were included in this study. Inclusion criteria were (1) at least 2 years' follow-up, (2) available information related to the living habits (smoking and medication status), and (3) available information related to the presence of hypertension, diabetes mellitus, or hyperlipidemia. To identify potential independent risk factors of graft failure, univariate screening was performed and factors with significance at a level of P < 0.1 were entered in multivariate logistic regression models. Results. A total of 368 patients (209 ACI and 159 OCA) were included into our study. In the ACI group, 61 patients' (29.1%) graft failed. Univariate screening identified older age, female gender, defect size, higher prevalence of hypertension, and smoking as a predictor of graft failure. Following, multivariate logistic regression revealed female gender (odds ratio [OR] 1.02, P = 0.048), defect size (OR 1.07, P = 0.035), and hypertension (OR 3.73, P = 0.023) as significant independent risk factors predicting graft failure after ACI. In the OCA group, 29 patients' (18.2%) graft failed and none of the included factors demonstrated to be a potential risk factor for graft failure. Conclusion. Hypertension, defect size, and female gender seem to predict ACI graft failure but not OCA failure.

Role of Selective Serotonin Reuptake Inhibitors in Prognosis Dental Implants: A Retrospective Study

BACKGROUND

Many recent research shows that antidepressants interfere with the osseointegration of implants. The main purpose of this study was to determine the association between selective serotonin reuptake inhibitors (SSRI) and dental implant failure.

MATERIALS AND METHODOLOGY

A retrospective study consisted of 410 patients (720 dental implants). Patients' records were used to retrieve the history of SSRI use and medication. The study consists of two groups. Group I (SSRI users) consisted of 128 patients (245 dental implants) patients, whereas Group II (non-SSRI users) was formed by 282 patients (475 dental implants). The implant failure rate was evaluated and statistically examined using the Chi-square test.

RESULTS

Group I had 30 implant failures with 13 (12%) males and 14 (11.8%) females, whereas Group II had 28 implant failures with 12 (6.3%) males and 16 (5.6%) females. In Group I, 26% of the implants failed in the age group >50 years, whereas it was 10.4% in Group II. However, in the age group <50 years, it was 6% and 4.2% Groups I and II, respectively. Group I shows that out of 40 implants in diabetic patients, 12 had failure, whereas in Group II, out of 32 implants placed in diabetics, 7 had failure. In smokers, 48% of the implants failed in Group I, and 29% in group II. In non-smokers the failure was seen in 7.7% cases in Group I and 2.1% cases in Group II. The difference was statistically significant (P < 0.05).

CONCLUSION

The usage of SSRIs is associated with an increased rate of implant failure. It has a deleterious effect on bone remodeling and leads to excessive osteoporosis.

Nanotechnological approach and bio-inspired materials to face degenerative diseases in aging

The aging of the world population is increasingly claimed as an alarming situation, since an ever-raising number of persons in advanced age but still physically active is expected to suffer from invalidating and degenerative diseases. The impairment of the endogenous healing potential provoked by the aging requires the development of more effective and personalized therapies, based on new biomaterials and devices able to direct the cell fate to stimulate and sustain the regrowth of damaged or diseased tissues. To obtain satisfactory results, also in cases where the cell senescence, typical of the elderly, makes the regeneration process harder and longer, the new solutions have to possess excellent ability to mimic the physiological extracellular environment and thus exert biomimetic stimuli on stem cells. To this purpose, the "biomimetic concept" is today recognized as elective to fabricate bioactive and bioresorbable devices such as hybrid osteochondral scaffolds and bioactive bone cements closely resembling the natural hard tissues and with enhanced regenerative ability. The review will illustrate some recent results related to these new biomimetic materials developed for application in different districts of the musculoskeletal system, namely bony, osteochondral and periodontal regions, and the spine. Further, it will be shown how new bioactive and superparamagnetic calcium phosphate nanoparticles can give enhanced results in cardiac regeneration and cancer therapy. Since tissue regeneration will be a major demand in the incoming decades, the high potential of biomimetic materials and devices is promising to significantly increase the healing rate and improve the clinical outcomes even in aged patients.

Prevalence of work-related musculoskeletal disorders among Egyptian printing workers evidenced by using serum biomarkers of inflammation, oxidative stress, muscle injury, and collagen type I turnover

OBJECTIVE

Printing workers experience a high rate of musculoskeletal disorders (MSDs). This study aims to determine the prevalence of MSDs, estimate serum biomarkers denoting musculoskeletal tissue changes, and determine some individual risk factors for MSDs among Egyptian printing workers.

METHODS

Eighty-five male printing workers and 90 male administrative employees (control group) were recruited from a printing press in Giza. A validated version of the standardized Nordic questionnaire was used. Serum biomarkers of inflammation (interleukin (IL)-1α, IL-1β, IL-6, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP)), cell stress or injury (malondialdehyde (MDA) and creatine kinase skeletal muscle (CK-MM)), and collagen metabolism (collagen-I carboxy-terminal propeptide (PICP) and type-I collagen cross-linked C-telopeptide (CTx)) were measured for all participants.

RESULTS

This study showed a significant (p < 0.001) prevalence of the musculoskeletal symptoms (76.5%) and significant (p < 0.001) elevation in the levels of all measured biomarkers among the printing workers (means ± SD: IL-1α = 1.55 ± 0.9, IL-1β = 1.53 ± 0.87, IL-6 = 1.55 ± 0.85, TNF-α = 4.9 ± 2.25, CRP = 6.78 ± 3.07, MDA = 3.41 ± 1.29, CK-MM = 132.47 ± 69.01, PICP = 103.48 ± 36.44, and CTx = 0.47 ± 0.16) when compared with their controls (prevalence: 34.4%; means ± SD: IL-1α = 0.88 ± 0.61, IL-1β = 0.96 ± 0.72, IL-6 = 1.03 ± 0.75, TNF-α = 2.56 ± 1.99, CRP = 2.36 ± 1.1, MDA = 0.85 ± 0.21, CK-MM = 53.48 ± 33.05, PICP = 56.49 ± 9.05, and CTx = 0.31 ± 0.06). Also, significant (p < 0.001) positive strong associations were observed between age, body mass index (BMI), and the duration of employment with all measured biomarkers, where all correlation coefficients were >0.7.

CONCLUSION

Printing workers suffer a high prevalence of work-related MSDs that might be related to some individual factors (age, BMI, and duration of employment). Consequently, preventive ergonomic interventions should be applied. Further studies should be done to elucidate the link between tissue changes and detected biomarkers to follow the initiation and progression of MSDs and study the effectiveness of curative interventions.

Potential of Soluble Decellularized Extracellular Matrix for Musculoskeletal Tissue Engineering - Comparison of Various Mesenchymal Tissues

Background

It is well studied that preparations of decellularized extracellular matrix (ECM) obtained from mesenchymal tissues can function as biological scaffolds to regenerate injured musculoskeletal tissues. Previously, we reported that soluble decellularized ECMs derived from meniscal tissue demonstrated excellent biocompatibility and produced meniscal regenerate with native meniscal anatomy and biochemical characteristics. We therefore hypothesized that decellularized mesenchymal tissue ECMs from various mesenchymal tissues should exhibit tissue-specific bioactivity. The purpose of this study was to test this hypothesis using porcine tissues, for potential applications in musculoskeletal tissue engineering.

Methods

Nine types of porcine tissue, including cartilage, meniscus, ligament, tendon, muscle, synovium, fat pad, fat, and bone, were decellularized using established methods and solubilized. Although the current trend is to develop tissue specific decellularization protocols, we selected a simple standard protocol across all tissues using Triton X-100 and DNase/RNase after mincing to compare the outcome. The content of sulfated glycosaminoglycan (sGAG) and hydroxyproline were quantified to determine the biochemical composition of each tissue. Along with the concentration of several growth factors, known to be involved in tissue repair and/or maturation, including bFGF, IGF-1, VEGF, and TGF-β1. The effect of soluble ECMs on cell differentiation was explored by combining them with 3D collagen scaffold culturing human synovium derived mesenchymal stem cells (hSMSCs).

Results

The decellularization of each tissue was performed and confirmed both histologically [hematoxylin and eosin (H&E) and 4’,6-diamidino-2-phenylindole (DAPI) staining] and on the basis of dsDNA quantification. The content of hydroxyproline of each tissue was relatively unchanged during the decellularization process when comparing the native and decellularized tissue. Cartilage and meniscus exhibited a significant decrease in sGAG content. The content of hydroxyproline in meniscus-derived ECM was the highest when compared with other tissues, while sGAG content in cartilage was the highest. Interestingly, a tissue-specific composition of most of the growth factors was measured in each soluble decellularized ECM and specific differentiation potential was particularly evident in cartilage, ligament and bone derived ECMs.

Conclusion

In this study, soluble decellularized ECMs exhibited differences based on their tissue of origin and the present results are important going forward in the field of musculoskeletal regeneration therapy.

Shoulder range of movement in the general population: age and gender stratified normative data using a community-based cohort

Background

An understanding of the average range of movement of the shoulder that is normally achievable is an important part of treatment for shoulder disorders. The average range of active shoulder flexion, abduction and external rotation was measured in a population cohort aged 20 years and over without shoulder pain and/or stiffness in order to provide normative shoulder range data.

Methods

Cross-sectional analysis using participants in a community-based longitudinal cohort study. There have been three stages of data collection – Stage 1 (1999–2003), Stage 2 (2004–2006) and Stage 3 (2008–2010). Each stage has consisted a of broad ranging computer assisted telephone interview, a self-complete questionnaire and a clinic assessment. Participants in this study are those who undertook assessments in Stage 2. The main outcome measures were active shoulder range of movement (flexion, abduction and external rotation) measured as part of the clinic assessment using a Plurimeter V inclinometer. Mean values were determined and analyses to examine differences between groups (sex and age) were undertaken using non-parametric tests.

Results

There were 2404 participants (51.5% male), mean age 45.8 years (SD 17.3, range 20–91). The average range of active right shoulder flexion was 161.5° for males and 158.5° for females, and active right shoulder abduction was 151.5° and 149.7° for males and females respectively. Shoulder range of movement declined with age, with mean right active shoulder flexion decreasing by 43° in males and 40.6° in females and right active shoulder abduction by 39.5° and 36.9° respectively. External rotation range also declined, particularly among females.

Conclusion

To our knowledge this is the largest community-based study providing normative data for active shoulder range of movement. This information can be used to set realistic goals for both clinical practice and clinical trials.

Recapitulation of cartilage/bone formation using iPSCs via biomimetic 3D rotary culture approach for developmental engineering

The recapitulation of cartilage/bone formation via guiding induced pluripotent stem cells (iPSCs) differentiation toward chondrogenic mesoderm lineage is an ideal approach to investigate cartilage/bone development and also for cartilage/bone regeneration. However, current induction protocols are time-consuming and complicated to follow. Here, we established a rapid and efficient approach that directly induce iPSCs differentiation toward chondrogenic mesoderm lineage by regulating the crucial Bmp-4 and FGF-2 signaling pathways using a 3D rotary suspension culture system. The mechanical stimulation from 3D rotary suspension accelerates iPSCs differentiation toward mesodermal and subsequent chondrogenic lineage via the Bmp-4-Smad1 and Tgf-β-Smad2/3 signaling pathways, respectively. The scaffold-free homogenous cartilaginous pellets or hypertrophic cartilaginous pellets derived from iPSCs within 28 days were capable of articular cartilage regeneration or vascularized bone regeneration via endochondral ossification in vivo, respectively. This biomimetic culture approach will contribute to research related to cartilage/bone development, regeneration, and hence to therapeutic applications in cartilage-/bone-related diseases.

Patients With Spinal Muscular Atrophy Use High Percentages of Trunk Muscle Capacity to Perform Seated Tasks

OBJECTIVE

The aim of the study was to investigate trunk function during seated upper limb tasks in patients with spinal muscular atrophy types 2 and 3.

DESIGN

Seventeen persons with spinal muscular atrophy and 15 healthy controls performed several tasks when sitting unsupported, such as reaching (and placing) forward and sideward. Joint torque and muscle activity were measured during maximum voluntary isometric contractions. Three-dimensional kinematics and normalized muscle activity were analyzed when performing tasks.

RESULTS

Trunk joint torques were significantly decreased, approximately 45%, in patients with spinal muscular atrophy compared with healthy controls. Active range of trunk motion was also significantly decreased in all directions. When performing tasks, the average back muscle activity was 27% and 56% of maximum voluntary isometric contractions for healthy controls and spinal muscular atrophy and for abdominal muscles 10% and 44% of maximum voluntary isometric contractions, respectively. Trunk range of motion did not differ when performing daily tasks.

CONCLUSIONS

The trunk of patients with spinal muscular atrophy is weaker compared with healthy controls, reflected by reduced trunk torques and decreased active range of motion. In addition, patients with spinal muscular atrophy use high percentages of their trunk muscle capacity to perform tasks. Clinicians should take this into account for intervention development, because using high percentages of the maximum muscle capacity results in fatigue and muscle overloading.

Prevalence of musculoskeletal complaints in urban communities in multi-ethnic Suriname: a cross-sectional study with the COPCORD methodology (stage 1, phase 1 and 2)

INTRODUCTION/OBJECTIVES

Musculoskeletal complaints (MSCs) are a major burden worldwide. In Suriname, a South American developing country, the epidemiology of MSCs and its related disorders is still unknown. Therefore, a cross-sectional survey was carried out to determine prevalence and risk factors of MSCs in urban areas of Suriname.

METHODS

This is the first Community Oriented Program for the Control of Rheumatic Diseases survey in a Caribbean Community. Trained interviewers collecting self-reported data conducted this house-to-house community-based survey. Data was analyzed using SPSS version 23 and Stata version 14.1.

RESULTS

The prevalence of MSCs was 62.1% with a higher prevalence rate among women compared with men (resp. 64.3% vs. 58.6%) (Odds ratio = 1.185; p ≤ 0.05). The most decisive self-reported variables associated with MSCs were older age (defined as ≥ 45 years) and moderate to heavy physical workload. The prevalence of MSCs was also associated with women, low educational level, smoking, alcohol use, high-intensity physical activity level, and body mass index (≥ 25 kg/m²). The highest prevalence of MSCs was found among African descendants (Maroons (68.8%) and Creoles (68.0%)), followed by the Indigenous (65.0%) and Asian descendants (Hindustani (64.3%) and Javanese (49.5%)). Most persons with MSCs (75.7%) reported multisite complaints with lower back, knee, and shoulder being the most frequently reported sites. In our study population, MSCs were not considered disabling (mean Health Assessment Questionnaire Disability Index score of 0.23).

CONCLUSIONS

The prevalence of MSCs in this urban multi-ethnic Surinamese community is high; therefore, future research is needed to further explore the burden of MSCs in Suriname.Key Points• Musculoskeletal complaints are highly prevalent in different ethnic groups in an urban Surinamese community; almost two-thirds of the population reported MSCs with the highest prevalence rate among women and African descendants.• The most decisive self-reported variables associated with MSCs were older age (defined as ≥ 45 years) and moderate to heavy physical workload. Gender, educational level, smoking, alcohol use, high-intensity physical activity, and body mass index were also significantly associated with musculoskeletal complaints.

Falling Again? Falls in Geriatric Adults-Risk Factors and Outcomes Associated With Recidivism

BACKGROUND

The elderly population is at increased risk of fall-related readmissions (FRRs). This study is aimed to identify the factors predictive of repeat falls and to analyze the associated outcomes.

METHODS

We studied the Nationwide Readmission Database for the year 2010 and identified the patients (≥65 years) who were admitted after falls, and from that subset, further analyzed patients with ≥1 FRRs. Descriptive statistics were used to analyze continuous and categorical variables. Multivariable logistic regression was used to identify predictors of readmission in geriatric patients after controlling for covariates.

RESULTS

A total of 358,581 initial fall-related admissions in geriatric adults were identified, and of these, 21,713 experienced ≥1 FRRs (6.06% risk of repeat fall-related admission). Females outnumbered males, and female gender was identified as an independent predictor of FRR (OR 1.10 95% CI 1.07-1.14 P = 0.000). The other independent predictors significantly associated with FRR were age (OR 1.007, 95% CI 1.005-1.009), depression (OR 1.25, 95% CI 1.21-1.30), drug abuse (OR 1.37, 95% CI 1.15-1.63), liver disease (OR 1.25, 95% CI 1.15-1.43, P < 0.001), psychosis (OR 1.16, 95% CI 1.09-1.23), valvular heart disease (OR 1.07, 95% CI 1.02-1.12), chronic pulmonary disease (OR 1.10, 95% CI 1.06-1.13), and number of chronic conditions (OR 1.022, 95% CI 1.016-1.29). Patients admitted emergently or urgently had higher odds of FRR (OR 1.44, 95% CI 1.36-1.52). Hospital demographic was a significant predictor of FRR, as hospitals with bed number >500 was associated with lower odds (OR 0.95, 95% CI 0.92-0.98, P < 0.001). Geriatric patients admitted at nonteaching hospitals and hospitals in large metro areas (population > 1 million) had higher odds of FRR (OR 1.10, 95% CI 1.03 - 1.16) and (OR 1.10, 95% C1 1.07-1.14), respectively. With respect to discharge disposition, patients in the FRR group were less likely to go home (5.9% versus 21.0%) or with home health care (12.6% versus 18.5%), but more likely to be discharged to skilled nursing or intermediate-care facilities (64.1% versus 54.9%) and short-term hospitals (2.8% versus 1.4%). The mortality rate was higher in the FRR group but was not statistically significant (OR 1.06, 95% CI 0.99-1.14).

CONCLUSIONS

Given the high burden of fall-related injuries and FRRs to patients and the health care system, it is essential to identify those who are at risk. This study provides a comprehensive list of high-risk predictors as well as the impact on patient outcomes, and hence a chance to intervene for patients with FRRs.

To help aging populations, classify organismal senescence

Comprehensive disease classification and staging is required to address unmet needs of aging populations

Pro-resolving lipid mediators: Agents of anti-ageing?

Inflammation is an essential response to injury and its timely and adequate resolution permits tissue repair and avoidance of chronic inflammation. Ageing is associated with increased inflammation, sub-optimal resolution and these act as drivers for a number of ageing-associated pathologies. We describe the role played by specialised proresolving lipid mediators (SPMs) in the resolution of inflammation and how insufficient levels of these mediators, or compromised responsiveness may play a role in the pathogenesis of many ageing-associated pathologies, e.g. Alzheimer's Disease, atherosclerosis, obesity, diabetes and kidney disease. Detailed examination of the resolution phase of inflammation highlights the potential to harness these lipid mediators and or mimetics of their bioactions, in particular, their synthetic analogues to promote effective resolution of inflammation, without compromising the host immune system.

Pre-obesity and obesity impacts on passive joint range of motion

Despite the prevalence of pre-obesity and obesity, the physical capabilities of pre-obese/obese individuals are not well documented. As an effort to address this, this study investigated the pre-obesity and obesity impacts on joint range of motion (RoM) for twenty-two body joint motions. A publicly available passive RoM dataset was analysed. Three BMI groups (normal-weight, pre-obese, and obese [Class I]) were statistically compared in joint RoM. The pre-obese and obese groups were found to have significantly smaller RoM means than the normal-weight for elbow flexion and supination, hip extension and flexion, knee flexion and ankle plantar flexion. The pre-obese and obese groups exhibited no significant inter-group mean RoM differences except for knee flexion; for knee flexion, the obese group had significantly smaller RoM means than the pre-obese. The findings would be useful for designing work tasks and products/systems for high BMI individuals and developing digital human models representing differently sized individuals. Practitioner summary: This study investigated the pre-obesity and obesity impacts on joint range of motion (RoM) by comparing three participant groups: normal-weight; pre-obese and obese. The pre-obese and obese groups had significantly smaller RoM means than the normal-weight for elbow flexion and supination; hip extension and flexion; knee flexion and ankle plantar flexion.

ABBREVIATIONS

ANCOVA: Analysis of Covariance; BMI: Body Mass Index; CI: Confidence Interval; RoM: Range of Motion; SPSS: Statistical Package for the Social Sciences.

Musculoskeletal Symptoms among Family Caregivers of Community-Dwelling Stroke Survivors in Nigeria

Introduction: Caring for stroke survivors may be burdensome with adverse consequences on caregivers' physical health. This study examined the prevalence of musculoskeletal symptoms and associated factors among family caregivers of stroke survivors in Nigeria. Methods: A hospital-based cross-sectional study involving 90 stroke caregiver and stroke survivor dyads was conducted. Data on the participants' demographics and post-stroke duration were obtained. Seven-day prevalence of musculoskeletal symptoms among the caregivers and level of stroke survivors' disability were respectively assessed using the Nordic Musculoskeletal Questionnaire and Modified Rankin Scale. Prevalence of musculoskeletal symptoms was presented as percentages while participants' characteristics associated with prevalence of musculoskeletal symptoms were examined using inferential statistics. Results: Mean (SD) age of caregivers and stroke survivors was 33.2 (10.7) years and 58.9 (9.7) years respectively. Majority of the caregivers were females (61.1%), and children of the stroke survivors (58.9%). Prevalence of musculoskeletal symptoms was 82.2%. The low back was the most affected body region (72.2%) followed by the upper back (40%) while musculoskeletal symptoms in the wrist was least prevalent (3.3%). Female caregivers, caregivers of female stroke survivors and spousal caregivers had significantly higher prevalence of musculoskeletal symptoms compared to other categories of caregivers. Only 5 (5.6%) caregivers had however received any training on safe care giving methods while only 21 (28.4%) caregivers with musculoskeletal symptoms had received treatment. Conclusion: With the high prevalence of musculoskeletal symptoms among family caregivers of stroke survivors, effective preventive strategies including training and education as well as timely access to treatment would be required.

Normative Values of Physical Examinations Commonly Used for Cerebral Palsy

PURPOSE

The aim of this study was to establish normative values and to identify age-related change in physical examinations that are commonly used while evaluating patients with cerebral palsy (CP).

MATERIALS AND METHODS

One hundred four healthy volunteers (mean age 36 years, standard deviation 15 years) were enrolled and divided into four age groups: 13-20, 21-35, 36-50, and 51 years and older. The eighteen physical examination tests for CP were selected by five orthopedic surgeons in consensus-building session. The measurements were taken by three orthopedic surgeons.

RESULTS

There was no significant difference in the measures of physical examination among all the age groups, except for the Staheli test (p=0.002). The post hoc test revealed that the mean hip extension was 2.7° higher in the 13-20-year-old group than in the other age groups. The bilateral popliteal angle had a tendency to increase in those over 36-years-old. There were 31 participants (30%) with a unilateral popliteal angle greater than 40°.

CONCLUSION

We documented normative values that can be widely used for evaluating CP in patients 13 years and older.

Knee Cartilage Thickness, T1ρ and T2 Relaxation Time Are Related to Articular Cartilage Loading in Healthy Adults

Cartilage is responsive to the loading imposed during cyclic routine activities. However, the local relation between cartilage in terms of thickness distribution and biochemical composition and the local contact pressure during walking has not been established. The objective of this study was to evaluate the relation between cartilage thickness, proteoglycan and collagen concentration in the knee joint and knee loading in terms of contact forces and pressure during walking. 3D gait analysis and MRI (3D-FSE, T1ρ relaxation time and T2 relaxation time sequence) of fifteen healthy subjects were acquired. Experimental gait data was processed using musculoskeletal modeling to calculate the contact forces, impulses and pressure distribution in the tibiofemoral joint. Correlates to local cartilage thickness and mean T1ρ and T2 relaxation times of the weight-bearing area of the femoral condyles were examined. Local thickness was significantly correlated with local pressure: medial thickness was correlated with medial condyle contact pressure and contact force, and lateral condyle thickness was correlated with lateral condyle contact pressure and contact force during stance. Furthermore, average T1ρ and T2 relaxation time correlated significantly with the peak contact forces and impulses. Increased T1ρ relaxation time correlated with increased shear loading, decreased T1ρ and T2 relaxation time correlated with increased compressive forces and pressures. Thicker cartilage was correlated with higher condylar loading during walking, suggesting that cartilage thickness is increased in those areas experiencing higher loading during a cyclic activity such as gait. Furthermore, the proteoglycan and collagen concentration and orientation derived from T1ρ and T2 relaxation measures were related to loading.

Recovery from volumetric muscle loss injury: A comparison between young and aged rats

Termed volumetric muscle loss (VML), the bulk loss of skeletal muscle tissue either through trauma or surgery overwhelms the capacity for repair, leading to the formation of non-contractile scar tissue. The myogenic potential, along with other factors that influence wound repair are known to decline with age. In order to develop effective treatment strategies for VML injuries that are effective across a broad range of patient populations, it is necessary to understand how the response to VML injury is affected by aging. Towards this end, this study was conducted to compare the response of young and aged animal groups to a lower extremity VML injury. Young (3months, n=12) and aged (18months, n=8) male Fischer 344 rats underwent surgical VML injury of the tibialis anterior muscle. Three months after VML injury it was found that young TA muscle was on average 16% heavier than aged muscle when no VML injury was performed and 25% heavier when comparing VML treated young and aged animals (p<0.0001, p<0.0001). Peak contractile force for both the young and aged groups was found to decrease significantly following VML injury, producing 65% and 59% of the contralateral limbs' peak force, respectively (p<0.0001). However, there were no differences found for peak contractile force based on age, suggesting that VML affects muscle's ability to repair, regardless of age. In this study, we used the ratio of collagen I to MyoD expression as a metric for fibrosis vs. myogenesis. Decreasing fiber cross-sectional area with advancing age (p<0.005) coupled with the ratio of collagen I to MyoD expression, which increased with age, supports the thought that regeneration is impaired in the aged population in favor of fibrosis (p=0.0241). This impairment is also exacerbated by the contribution of VML injury, where a 77-fold increase in the ratio of collagen I to MyoD was observed in the aged group (p<0.0002). The aged animal model described in this study provides a tool for investigators exploring not only the development of VML injury strategies but also the effect of aging on muscle regeneration.

Proteomics of Skeletal Muscle: Focus on Insulin Resistance and Exercise Biology

Skeletal muscle is the largest tissue in the human body and plays an important role in locomotion and whole body metabolism. It accounts for ~80% of insulin stimulated glucose disposal. Skeletal muscle insulin resistance, a primary feature of Type 2 diabetes, is caused by a decreased ability of muscle to respond to circulating insulin. Physical exercise improves insulin sensitivity and whole body metabolism and remains one of the most promising interventions for the prevention of Type 2 diabetes. Insulin resistance and exercise adaptations in skeletal muscle might be a cause, or consequence, of altered protein expressions profiles and/or their posttranslational modifications (PTMs). Mass spectrometry (MS)-based proteomics offer enormous promise for investigating the molecular mechanisms underlying skeletal muscle insulin resistance and exercise-induced adaptation; however, skeletal muscle proteomics are challenging. This review describes the technical limitations of skeletal muscle proteomics as well as emerging developments in proteomics workflow with respect to samples preparation, liquid chromatography (LC), MS and computational analysis. These technologies have not yet been fully exploited in the field of skeletal muscle proteomics. Future studies that involve state-of-the-art proteomics technology will broaden our understanding of exercise-induced adaptations as well as molecular pathogenesis of insulin resistance. This could lead to the identification of new therapeutic targets.

Joint dysfunction and functional decline in middle age myostatin null mice

Since its discovery as a potent inhibitor for muscle development, myostatin has been actively pursued as a drug target for age- and disease-related muscle loss. However, potential adverse effects of long-term myostatin deficiency have not been thoroughly investigated. We report herein that male myostatin null mice (mstn(-/-)), in spite of their greater muscle mass compared to wild-type (wt) mice, displayed more significant functional decline from young (3-6months) to middle age (12-15months) than age-matched wt mice, measured as gripping strength and treadmill endurance. Mstn(-/-) mice displayed markedly restricted ankle mobility and degenerative changes of the ankle joints, including disorganization of bone, tendon and peri-articular connective tissue, as well as synovial thickening with inflammatory cell infiltration. Messenger RNA expression of several pro-osteogenic genes was higher in the Achilles tendon-bone insertion in mstn(-/-) mice than wt mice, even at the neonatal age. At middle age, higher plasma concentrations of growth factors characteristic of excessive bone remodeling were found in mstn(-/-) mice than wt controls. These data collectively indicate that myostatin may play an important role in maintaining ankle and wrist joint health, possibly through negative regulation of the pro-osteogenic WNT/BMP pathway.

Ghrelin Promotes Functional Angiogenesis in a Mouse Model of Critical Limb Ischemia Through Activation of Proangiogenic MicroRNAs

Current therapeutic strategies for the treatment of critical limb ischemia (CLI) have only limited success. Recent in vitro evidence in the literature, using cell lines, proposes that the peptide hormone ghrelin may have angiogenic properties. In this study, we aim to investigate if ghrelin could promote postischemic angiogenesis in a mouse model of CLI and, further, identify the mechanistic pathway(s) that underpin ghrelin's proangiogenic properties. CLI was induced in male CD1 mice by femoral artery ligation. Animals were then randomized to receive either vehicle or acylated ghrelin (150 μg/kg sc) for 14 consecutive days. Subsequently, synchrotron radiation microangiography was used to assess hindlimb perfusion. Subsequent tissue samples were collected for molecular and histological analysis. Ghrelin treatment markedly improved limb perfusion by promoting the generation of new capillaries and arterioles (internal diameter less than 50 μm) within the ischemic hindlimb that were both structurally and functionally normal; evident by robust endothelium-dependent vasodilatory responses to acetylcholine. Molecular analysis revealed that ghrelin's angiogenic properties were linked to activation of prosurvival Akt/vascular endothelial growth factor/Bcl-2 signaling cascade, thus reducing the apoptotic cell death and subsequent fibrosis. Further, ghrelin treatment activated proangiogenic (miR-126 and miR-132) and antifibrotic (miR-30a) microRNAs (miRs) while inhibiting antiangiogenic (miR-92a and miR-206) miRs. Importantly, in vitro knockdown of key proangiogenic miRs (miR-126 and miR-132) inhibited the angiogenic potential of ghrelin. These results therefore suggest that clinical use of ghrelin for the early treatment of CLI may be a promising and potent inducer of reparative vascularization through modulation of key molecular factors.

Efeitos de oito semanas de treinamento com estimulação elétrica neuromuscular nas razões de ativação muscular / torque de idosas com osteoartrite

Introdução: O envelhecimento causa prejuízos no sistema musculoesquelético que podem ocasionar a osteoartrite, provocando degeneração da cartilagem articular e, consequentemente, perdas funcionais a idosos acometidos. Por outro lado, a estimulação elétrica neuromuscular é utilizada como treinamento para fortalecimento muscular.Objetivo: Investigar o efeito de oito semanas de treinamento com neuromuscular electrical stimulation (NMES) nas razões de ativação root mean square (RMS) / torque dos músculos extensores do joelho em idosas com osteoartrite. Metodologia: Vinte e quatro idosas foram divididas em dois grupos: grupo saudável (SAU; n=12) e grupo osteoartrite (OA; n=12). O grupo OA foi submetido a oito semanas de treinamento com NMES e tempo de aplicação variando de 18 a 32 minutos e frequência semanal de três vezes.Resultados: No grupo OA, ocorreu um aumento dos valores RMS pós-treinamento comparado com o pré-treinamento (p<0,05). O grupo SAU permaneceu igual ao grupo OA pós-treinamento (p>0,05). O torque do quadríceps aumentou pós-treinamento no grupo OA no ângulo de 90° de flexão do joelho, contudo, o grupo SAU apresentou maior produção de torque em todos os ângulos avaliados (p<0,05). No grupo OA, houve aumento das razões RMS / torque após o treinamento para os ângulos de 60º, 75º e 90º de flexão do joelho (p<0,05), mas não diferindo do grupo SAU (p>0,05).Conclusão: Oito semanas de treinamento com NMES aumentaram a ativação muscular e torque dos músculos extensores do joelho no grupo osteoartrite, mas não foram capazes de gerar adaptações suficientes para igualar os mesmos ao grupo saudável.

Structure and composition of arytenoid cartilage of the bullfrog (Lithobates catesbeianus) during maturation and aging

The aging process induces progressive and irreversible changes in the structural and functional organization of animals. The objective of this study was to evaluate the effects of aging on the structure and composition of the extracellular matrix of the arytenoid cartilage found in the larynx of male bullfrogs (Lithobates catesbeianus) kept in captivity for commercial purposes. Animals at 7, 180 and 1080 days post-metamorphosis (n=10/age) were euthanized and the cartilage was removed and processed for structural and biochemical analysis. For the structural analyses, cartilage sections were stained with picrosirius, toluidine blue, Weigert's resorcin-fuchsin and Von Kossa stain. The sections were also submitted to immunohistochemistry for detection of collagen types I and II. Other samples were processed for the ultrastructural and cytochemical analysis of proteoglycans. Histological sections were used to chondrocyte count. The number of positive stainings for proteoglycans was quantified by ultrastructural analysis. For quantification and analysis of glycosaminoglycans were used the dimethyl methylene blue and agarose gel electrophoresis methods. The chloramine T method was used for hydroxyproline quantification. At 7 days, basophilia was observed in the pericellular and territorial matrix, which decreased in the latter over the period studied. Collagen fibers were arranged perpendicular to the major axis of the cartilaginous plate and were thicker in older animals. Few calcification areas were observed at the periphery of the cartilage specimens in 1080-day-old animals. Type II collagen was present throughout the stroma at the different ages. Elastic fibers were found in the stroma and perichondrium and increased with age in the two regions. Proteoglycan staining significantly increased from 7 to 180 days and reduced at 1080 days. The amount of total glycosaminoglycans was higher in 180-day-old animals compared to the other ages, with marked presence of chondroitin- and dermatan-sulfate especially in this age. The content of hydroxyproline, which infers the total collagen concentration, was higher in 1080-day-old animals compared to the other ages. The results demonstrated the elastic nature of the arytenoid cartilage of L. catesbeianus and the occurrence of age-related changes in the structural organization and composition of the extracellular matrix. These changes may contribute to alter the function of the larynx in the animal during aging.

Progressive resistance strength training and the related injuries in older adults: the susceptibility of the shoulder

The benefits of progressive resistance training (PRT) among the older adults are evident, especially in the prevention of sarcopenia and improving muscle strength, which reverse the age-related loss of functional ability. However, PRT carries some risk, particularly when participants are older adults with a certain degree of muscle weakness. The purpose of this article is to discuss the PRT-related injuries, and present an overview of documented shoulder injuries among the elderly, discerning possible mechanisms of injury and risk factors. A literature search was conducted in the PUBMED database to identify the relevant literature using combinations of keywords: strength-training injuries, resistance-training injuries, sports injuries in the elderly, shoulder complex, shoulder injury, and shoulder disorder. Acute and chronic injuries attributed to PRT have been cited in the epidemiological literature. The shoulder complex, has been alluded to as one of the most prevalent regions of injury, particularly in exercises that place the arm extended above the head and posterior to the trunk. However, the risk for injuries appears to be higher for testing than for training itself. One-repetition maximum strength testing may result in a greater injury risk. This technique, though acceptable, needs additional precautions in inexperience older adults to prevent injury. Thus, the best treatment for PRT age-related injuries is prevention. Appropriate and individualized training programs, the use of safe equipment, careful warming up and cooling down, correct range of motion, progressive intensity training, cardiovascular and musculoskeletal fitness are essential aspects of injury prevention among the elderly.

Glycation cross-linking induced mechanical-enzymatic cleavage of microscale tendon fibers

Recent molecular modeling data using collagen peptides predicted that mechanical force transmitted through intermolecular cross-links resulted in collagen triple helix unwinding. These simulations further predicted that this unwinding, referred to as triple helical microunfolding, occurred at forces well below canonical collagen damage mechanisms. Based in large part on these data, we hypothesized that mechanical loading of glycation cross-linked tendon microfibers would result in accelerated collagenolytic enzyme damage. This hypothesis is in stark contrast to reports in literature that indicated that individually mechanical loading or cross-linking each retards enzymatic degradation of collagen substrates. Using our Collagen Enzyme Mechano-Kinetic Automated Testing (CEMKAT) System we mechanically loaded collagen-rich tendon microfibers that had been chemically cross-linked with sugar and tested for degrading enzyme susceptibility. Our results indicated that cross-linked fibers were >5 times more resistant to enzymatic degradation while unloaded but became highly susceptible to enzyme cleavage when they were stretched by an applied mechanical deformation.

Nucleus pulposus degeneration alters properties of resident progenitor cells

BACKGROUND CONTEXT

The intervertebral disc (IVD) possesses a minimal capability for self-repair and regeneration. Changes in the differentiation of resident progenitor cells can represent diminished tissue regeneration and a loss of homeostasis. We previously showed that progenitor cells reside in the nucleus pulposus (NP). The effect of the degenerative process on these cells remains unclear.

PURPOSE

We sought to explore the effect of IVD degeneration on the abundance of resident progenitor cells in the NP, their differentiation potential, and their ability to give rise to NP-like cells. We hypothesize that disc degeneration affects those properties.

STUDY DESIGN

Nucleus pulposus cells derived from healthy and degenerated discs were methodically compared for proliferation, differentiation potential, and ability to generate NP-like cells.

METHODS

Intervertebral disc degeneration was induced in 10 skeletally, mature mini pigs using annular injury approach. Degeneration was induced in three target discs, whereas intact adjacent discs served as controls. The disc degeneration was monitored using magnetic resonance imaging for 6 to 8 weeks. After there was a clear evidence of degeneration, we isolated and compared cells from degenerated discs (D-NP cells [NP-derived cells from porcine degenerated discs]) with cells isolated from healthy discs (H-NP cells) obtained from the same animal.

RESULTS

The comparison showed that D-NP cells had a significantly higher colony-forming unit rate and a higher proliferation rate in vitro. Our data also indicate that although both cell types are able to differentiate into mesenchymal lineages, H-NP cells exhibit significantly greater differentiation toward the chondrogenic lineage and NP-like cells than D-NP cells, displaying greater production of glycosaminoglycans and higher gene expression of aggrecan and collagen IIa.

CONCLUSIONS

Based on these findings, we conclude that IVD degeneration has a meaningful effect on the cells in the NP. D-NP cells clearly go through the regenerative process; however, this process is not powerful enough to facilitate full regeneration of the disc and reverse the degenerative course. These findings facilitate deeper understanding of the IVD degeneration process and trigger further studies that will contribute to development of novel therapies for IVD degeneration.

The ageing haematopoietic stem cell compartment

Stem cell ageing underlies the ageing of tissues, especially those with a high cellular turnover. There is growing evidence that the ageing of the immune system is initiated at the very top of the haematopoietic hierarchy and that the ageing of haematopoietic stem cells (HSCs) directly contributes to changes in the immune system, referred to as immunosenescence. In this Review, we summarize the phenotypes of ageing HSCs and discuss how the cell-intrinsic and cell-extrinsic mechanisms of HSC ageing might promote immunosenescence. Stem cell ageing has long been considered to be irreversible. However, recent findings indicate that several molecular pathways could be targeted to rejuvenate HSCs and thus to reverse some aspects of immunosenescence.

Aging of the microenvironment influences clonality in hematopoiesis

The mechanisms of the age-associated exponential increase in the incidence of leukemia are not known in detail. Leukemia as well as aging are initiated and regulated in multi-factorial fashion by cell-intrinsic and extrinsic factors. The role of aging of the microenvironment for leukemia initiation/progression has not been investigated in great detail so far. Clonality in hematopoiesis is tightly linked to the initiation of leukemia. Based on a retroviral-insertion mutagenesis approach to generate primitive hematopoietic cells with an intrinsic potential for clonal expansion, we determined clonality of transduced hematopoietic progenitor cells (HPCs) exposed to a young or aged microenvironment in vivo. While HPCs displayed primarily oligo-clonality within a young microenvironment, aged animals transplanted with identical pool of cells displayed reduced clonality within transduced HPCs. Our data show that an aged niche exerts a distinct selection pressure on dominant HPC-clones thus facilitating the transition to mono-clonality, which might be one underlying cause for the increased age-associated incidence of leukemia.

Musculoskeletal disorders in the elderly

Musculoskeletal disorders are among the most common problems affecting the elderly. The resulting loss of mobility and physical independence can be particularly devastating in this population. The aim of this article is to present some of the most frequent musculoskeletal disorders of the elderly, such as fractures, osteoporosis, osteoarthritis, microcrystal disorders, infections, and tumors.