Dystrophin deficiency in canine X-linked muscular dystrophy in Japan (CXMDJ) alters myosin heavy chain expression profiles in the diaphragm more markedly than in the tibialis cranialis muscle

Transcriptional changes of genes encoding sarcoplasmic reticulum calcium binding and up-taking proteins in normal and Duchenne muscular dystrophy dogs

BACKGROUND

Cytosolic calcium overload contributes to muscle degradation in Duchenne muscular dystrophy (DMD). The sarcoplasmic reticulum (SR) is the primary calcium storage organelle in muscle. The sarco-endoplasmic reticulum ATPase (SERCA) pumps cytosolic calcium to the SR during muscle relaxation. Calcium is kept in the SR by calcium-binding proteins.

METHODS

Given the importance of the canine DMD model in translational studies, we examined transcriptional changes of SERCA (SERCA1 and SERCA2a), SERCA regulators (phospholamban, sarcolipin, myoregulin, and dwarf open reading frame), and SR calcium-binding proteins (calreticulin, calsequestrin 1, calsequestrin 2, and sarcalumenin) in skeletal muscle (diaphragm and extensor carpi ulnaris) and heart (left ventricle) in normal and affected male dogs by droplet digital PCR before the onset (≤ 2-m-old), at the active stage (8 to 16-m-old), and at the terminal stage (30 to 50-m-old) of the disease. Since many of these proteins are expressed in a fiber type-specific manner, we also evaluated fiber type composition in skeletal muscle.

RESULTS

In affected dog skeletal muscle, SERCA and its regulators were down-regulated at the active stage, but calcium-binding proteins (except for calsequestrin 1) were upregulated at the terminal stage. Surprisingly, nominal differences were detected in the heart. We also examined whether there exists sex-biased expression in 8 to 16-m-old dogs. Multiple transcripts were significantly downregulated in the heart and extensor carpi ulnaris muscle of female dogs. In fiber type analysis, we found significantly more type I fiber in the diaphragm of 8 to 16-m-old affected dogs, and significantly more type II fibers in the extensor carpi ulnaris of 30 to 50-m-old affected dogs. However, no difference was detected between male and female dogs.

CONCLUSIONS

Our study adds new knowledge to the understanding of muscle calcium regulation in normal and dystrophic canines.

Wearable motion-based platform for functional spine health assessment

INTRODUCTION

Low back pain is a significant burden to society and the lack of reliable outcome measures, combined with a prevailing inability to quantify the biopsychosocial elements implicated in the disease, impedes clinical decision-making and distorts treatment efficacy. This paper aims to validate the utility of a biopsychosocial spine platform to provide standardized wearable sensor-derived functional motion assessments to assess spine function and differentiate between healthy controls and patients. Secondarily, we explored the correlation between these motion features and subjective biopsychosocial measures.

METHODS

An observational study was conducted on healthy controls (n=50) and patients with low back pain (n=50) to validate platform utility. The platform was used to conduct functional assessments along with patient-reported outcome assessments to holistically document cohort differences. Our primary outcomes were motion features; and our secondary outcomes were biopsychosocial measures (pain, function, etc).

RESULTS

Our results demonstrated statistically significant differences in motion features between healthy and patient cohorts across anatomical planes. Importantly, we found velocity and acceleration in the axial plane showed the largest difference, with healthy controls having 49.7% and 55.7% higher values, respectively, than patients. In addition, we found significant correlations between motion features and biopsychosocial measures for pain, physical function and social role only.

CONCLUSIONS

Our study validated the use of wearable sensor-derived functional motion metrics in differentiating healthy controls and patients. Collectively, this technology has the potential to facilitate holistic biopsychosocial evaluations to enhance spine care and improve patient outcomes.

TRIAL REGISTRATION NUMBER

NCT05776771.

Photometric analysis of the relationship between craniovertebral angle and facial profile in children aged 10-12 years

Background

Head posture deviation is seen in 52.5 % of children aged 6-15 years. Studies have shown that poor posture habits can impair muscle function during craniofacial growth and development. A muscle imbalance causes abnormal positioning of dental and skeletal structures, a condition that exerts negative impacts, such as changes in facial morphology.

Objective

To determine through photometric analysis the relationship between craniovertebral angle as a function of head posture and glabella-subnasale-pogonion (G-Sn-Pg) angle as a function of facial profile in 10-12-year-old children, and the results will help to avoid facial development issues.

Methods

Thirty-three subjects met the inclusion criteria. Their craniovertebral angles and facial profiles were measured using lateral photometry and ImageJ. The craniovertebral angle was determined by connecting the tragus and C7 with a horizontal line, whereas the facial profile angle was determined by connecting the glabella, subnasale, and pogonion. The relationship between the craniovertebral and G-Sn-Pg angle values was analyzed using the Pearson correlation test.

Results

A significant relationship was observed between the craniovertebral angle and the G-Sn- Pg angle (p < 0.05), although such a relationship was weak (r = 0.373).

Conclusion

A more forward head posture is associated with a more convex facial profile, and this relationship is useful for the early prevention and treatment.

Evaluation of the Craniovertebral Angle in Standing versus Sitting Positions in Young Adults with and without Severe Forward Head Posture

The purpose of this study was to examine the effects of standing versus sitting body position on the craniovertebral angle (CVA) in young adults without pathology; and to investigate whether mean differences between positional CVA measures in subjects with severe forward head posture (FHP) are distinct from age-matched controls with normal head posture. Ninety-eight young adults (68 women, 30 men) without pathology (OVERALL; n = 98) volunteered for the study; those with CVA > 53° were also included in a normal posture group (NORM; n = 14); those with CVA < 45° were also included in a severe FHP group (SEV; n = 15). CVA assessments were conducted in standing and sitting. Mean difference comparison of change in mean CVA between conditions revealed significantly (p < 0.05) higher CVA values in standing condition (OVERALL: 50.0 ± 5.2°; NORM: 56.6 ± 2.7°; SEV: 41.2 ± 3.2°) compared to sitting condition (OVERALL: 47.8 ± 5.7°; NORM: 55.9 ± 2.8°; SEV: 39.0 ± 4.0°). Mean difference comparison of between-group change in mean CVA between conditions revealed greater CVA change (p < 0.05) in the SEV group (2.2 ± 2.1°) versus the NORM group (0.8 ± 1.2°). Sitting CVA values may be lower (indicating greater FHP) than standing CVA values in young adults. Differences between standing and sitting CVA measures may be greater in young adults with severe FHP compared to peers with normal head posture. Study findings support standing as a standardized body position for CVA assessment in young adults without pathology.

Longitudinal assessment of skeletal muscle functional mechanics in the DE50-MD dog model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin (DMD) gene, is associated with fatal muscle degeneration and atrophy. Patients with DMD have progressive reductions in skeletal muscle strength and resistance to eccentric muscle stretch. Using the DE50-MD dog model of DMD, we assessed tibiotarsal joint (TTJ) flexor and extensor force dynamics, and the resistance of dystrophic muscle to eccentric stretch. Male DE50-MD and wild-type (WT) dogs were analysed every 3 months until 18 months of age. There was an age-associated decline in eccentric contraction resistance in DE50-MD TTJ flexors that discriminated, with high statistical power, WT from DE50-MD individuals. For isometric contraction, at the majority of timepoints, DE50-MD dogs had lower maximum absolute and relative TTJ flexor force, reduced TTJ muscle contraction times and prolonged relaxation compared to those in WT dogs. Cranial tibial muscles, the primary TTJ flexor, of 18-month-old DE50-MD dogs had significant numbers of regenerating fibres as expected, but also fewer type I fibres and more hybrid fibres than those in WT dogs. We conclude that these parameters, in particular, the eccentric contraction decrement, could be used as objective outcome measures for pre-clinical assessment in DE50-MD dogs.

Slow or fast: Implications of myofibre type and associated differences for manifestation of neuromuscular disorders

Many neuromuscular disorders can have a differential impact on a specific myofibre type, forming the central premise of this review. The many different skeletal muscles in mammals contain a spectrum of slow- to fast-twitch myofibres with varying levels of protein isoforms that determine their distinctive contractile, metabolic, and other properties. The variations in functional properties across the range of classic 'slow' to 'fast' myofibres are outlined, combined with exemplars of the predominantly slow-twitch soleus and fast-twitch extensor digitorum longus muscles, species comparisons, and techniques used to study these properties. Other intrinsic and extrinsic differences are discussed in the context of slow and fast myofibres. These include inherent susceptibility to damage, myonecrosis, and regeneration, plus extrinsic nerves, extracellular matrix, and vasculature, examined in the context of growth, ageing, metabolic syndrome, and sexual dimorphism. These many differences emphasise the importance of carefully considering the influence of myofibre-type composition on manifestation of various neuromuscular disorders across the lifespan for both sexes. Equally, understanding the different responses of slow and fast myofibres due to intrinsic and extrinsic factors can provide deep insight into the precise molecular mechanisms that initiate and exacerbate various neuromuscular disorders. This focus on the influence of different myofibre types is of fundamental importance to enhance translation for clinical management and therapies for many skeletal muscle disorders.

Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a lethal muscle disease caused by absence of the protein dystrophin, which acts as a structural link between the basal lamina and contractile machinery to stabilize muscle membranes in response to mechanical stress. In DMD, mechanical stress leads to exaggerated membrane injury and fiber breakdown, with fast fibers being the most susceptible to damage. A major contributor to this injury is muscle contraction, controlled by the motor protein myosin. However, how muscle contraction and fast muscle fiber damage contribute to the pathophysiology of DMD has not been well characterized. We explored the role of fast skeletal muscle contraction in DMD with a potentially novel, selective, orally active inhibitor of fast skeletal muscle myosin, EDG-5506. Surprisingly, even modest decreases of contraction (<15%) were sufficient to protect skeletal muscles in dystrophic mdx mice from stress injury. Longer-term treatment also decreased muscle fibrosis in key disease-implicated tissues. Importantly, therapeutic levels of myosin inhibition with EDG-5506 did not detrimentally affect strength or coordination. Finally, in dystrophic dogs, EDG-5506 reversibly reduced circulating muscle injury biomarkers and increased habitual activity. This unexpected biology may represent an important alternative treatment strategy for Duchenne and related myopathies.

Effect of acute ankle experimental pain on lower limb motor control assessed by the modified star excursion balance test

Introduction

Following most musculoskeletal injuries, motor control is often altered. Acute pain has been identified as a potential contributing factor. However, there is little evidence of this interaction for acute pain following ankle sprains. As pain is generally present following this type of injury, it would be important to study the impact of acute pain on ankle motor control. To do so, a valid and reliable motor control test frequently used in clinical settings should be used. Therefore, the objective of this study was therefore to assess the effect of acute ankle pain on the modified Star Excursion Balance Test reach distance.

Methods

Using a cross-sectional design, 48 healthy participants completed the modified Star Excursion Balance Test twice (mSEBT1 and mSEBT2). Following the first assessment, they were randomly assigned to one of three experimental groups: Control (no stimulation), Painless (non-nociceptive stimulation) and Painful (nociceptive stimulation). Electrodes were placed on the right lateral malleolus to deliver an electrical stimulation during the second assessment for the Painful and Painless groups. A generalized estimating equations model was used to compare the reach distance between the groups/conditions and assessments.

Results

Post-hoc test results: anterior (7.06 ± 1.54%; p < 0.0001) and posteromedial (6.53 ± 1.66%; p < 0.001) directions showed a significant reach distance reduction when compared to baseline values only for the Painful group. Regarding the anterior direction, this reduction was larger than the minimal detectable change (5.87%).

Conclusion

The presence of acute pain during the modified Star Excursion Balance Test can affect performance and thus might interfere with the participant's lower limb motor control. As none of the participants had actual musculoskeletal injury, this suggests that pain and not only musculoskeletal impairments could contribute to the acute alteration in motor control.

Histological Methods to Assess Skeletal Muscle Degeneration and Regeneration in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a progressive disease caused by the loss of function of the protein dystrophin. This protein contributes to the stabilisation of striated cells during contraction, as it anchors the cytoskeleton with components of the extracellular matrix through the dystrophin-associated protein complex (DAPC). Moreover, absence of the functional protein affects the expression and function of proteins within the DAPC, leading to molecular events responsible for myofibre damage, muscle weakening, disability and, eventually, premature death. Presently, there is no cure for DMD, but different treatments help manage some of the symptoms. Advances in genetic and exon-skipping therapies are the most promising intervention, the safety and efficiency of which are tested in animal models. In addition to in vivo functional tests, ex vivo molecular evaluation aids assess to what extent the therapy has contributed to the regenerative process. In this regard, the later advances in microscopy and image acquisition systems and the current expansion of antibodies for immunohistological evaluation together with the development of different spectrum fluorescent dyes have made histology a crucial tool. Nevertheless, the complexity of the molecular events that take place in dystrophic muscles, together with the rise of a multitude of markers for each of the phases of the process, makes the histological assessment a challenging task. Therefore, here, we summarise and explain the rationale behind different histological techniques used in the literature to assess degeneration and regeneration in the field of dystrophinopathies, focusing especially on those related to DMD.

Donor age effects on in vitro chondrogenic and osteogenic differentiation performance of equine bone marrow- and adipose tissue-derived mesenchymal stromal cells

BACKGROUND

Bone marrow (BM)- and adipose tissue (AT)-derived mesenchymal stromal cells (MSCs) have shown potential as cell-based therapies for cartilage and bone injuries and are used increasingly in human and veterinary practice to facilitate the treatment of orthopedic conditions. However, human and rodent studies have documented a sharp decline in chondrogenic and osteogenic differentiation potential with increasing donor age, which may be problematic for the important demographic of older orthopedic patients. The aim of this study was to identify the effect of donor age on the chondrogenic and osteogenic differentiation performance of equine BM- and AT-MSCs in vitro. BM- and AT-MSCs and dermal fibroblasts (biological negative control) were harvested from horses in five different age groups (n = 4, N = 60); newborn (0 days), yearling (15-17 months), adult (5-8 years), middle-aged (12-18 years), and geriatric (≥ 22 years). Chondrogenic differentiation performance was assessed quantitatively by measuring pellet size, matrix proteoglycan levels, and gene expression of articular cartilage biomarkers. Osteogenic differentiation performance was assessed quantitatively by measuring alkaline phosphatase activity, calcium deposition, and gene expression of bone biomarkers.

RESULTS

Chondrogenic and osteogenic differentiation performance of equine BM- and AT-MSCs declined with increasing donor age. BM-MSCs had a higher chondrogenic differentiation performance. AT-MSCs showed minimal chondrogenic differentiation performance in all age groups. For osteogenesis, alkaline phosphatase activity was also higher in BM-MSCs, but BM-MSCs calcium deposition was affected by donor age earlier than AT-MSCs. Chondrogenic and osteogenic differentiation performance of BM-MSCs exhibited a decline as early as between the newborn and yearling samples. Steady state levels of mRNA encoding growth factors, chondrogenic, and osteogenic biomarkers were lower with increasing donor age in both MSC types.

CONCLUSIONS

The data showed that chondrogenic and osteogenic differentiation performance of equine BM-MSCs declined already in yearlings, and that AT-MSCs showed minimal chondrogenic potential, but were affected later by donor age with regards to osteogenesis (calcium deposition). The results highlight the importance of donor age considerations and MSC selection for cell-based treatment of orthopedic injuries and will help inform clinicians on when to implement or potentially cryopreserve cells. Moreover, the study provides molecular targets affected by donor age.

Cooled and traditional thermal radiofrequency ablation of genicular nerves in patients with chronic knee pain: a comparative outcomes analysis

INTRODUCTION

Genicular nerve radiofrequency ablation (GNRFA) is a minimally invasive intervention for patients with chronic knee pain (CKP) not responding to conservative treatments. Few investigations have compared treatment outcomes of cooled-RFA (c-RFA) and thermal-RFA (t-RFA), two common approaches of GNRFA. This study aims to investigate and compare outcomes, including probability of treatment success, between c-RFA and t-RFA in patients with CKP.

METHODS

This retrospective cohort study analyzed a total of 208 propensity score matched patients, including 104 patients who received c-RFA and 104 patients who received t-RFA. The primary outcome was probability of pain relief after the procedure, defined as reduction in Numeric Rating Scale (NRS) pain score of 2 or greater. The secondary outcomes were degree of NRS pain score reductions, duration of relief, and the probability of patients receiving TKA within 1 year of treatment.

RESULTS

T-RFA was associated with a higher probability of pain relief within 1, 3, and 6 months after procedure when compared with c-RFA. Probabilities of pain relief from t-RFA and c-RFA were 62% (95% CI 51% to 71%) and 43% (95% CI 34% to 53%; p=0.01) within 1 month, 78% (95% CI 68% to 85%) and 55% (95% CI 45% to 64%; p<0.001) within 3 months, and 79% (95% CI 70% to 86%) and 59% (95% CI 49% to 68%; p<0.01) within 6 months, respectively. t-RFA was also associated with greater mean NRS pain score reduction at 1 month after procedure: -4.71 (95% CI -5.3 to -4.1) when compared with -3.59 (95% CI -4.3 to -2.9; p=0.02) from c-RFA. T-RFA and c-RFA were comparable in pain score reduction at 3, 6, 9 and 12 months after procedure. Both groups demonstrated comparable duration of relief and probability of patients receiving TKA within 1 year.

DISCUSSION

Both t-RFA and c-RFA effectively reduced NRS pain scores in most patients with CKP within the 1 year follow-up period. Genicular nerve t-RFA was associated with a higher probability of treatment success and a greater degree of pain relief at 1 month after the procedure when compared with c-RFA in propensity score matched patients with CKP.

Impact of persistent pain symptoms on work absence, health status and employment 18 months following disabling work-related injury or illness

OBJECTIVES

While most individuals physically injured at work will make a complete medical recovery, a portion of workers will experience persistent pain following their injury. This study estimated persistent pain prevalence and its association with health and return-to-work outcomes 18 months following the incidence of a disabling work-related injury.

METHODS

We studied 1131 workers disabled by a work-related injury who were recruited from a sampling frame of disability benefit claimants in Ontario, Canada. Work injuries and claim benefits characteristics from administrative data were linked with measures of work status, pain symptoms, and physical and mental health obtained from telephone interviews completed 18 months postinjury. Associations of persistent pain symptoms with health and employment outcomes 18 months postinjury were estimated using multinomial and linear regression.

RESULTS

Roughly 30% of participants reported no pain symptoms in the previous 4 weeks, 45% reported mild pain symptoms and 25% reported severe pain symptoms accompanied by substantial functional impairment. Workers with severe pain symptoms were more likely to not be currently working at 18 months (33%) vs those without pain symptoms (16%), and had poorer self-reported physical and mental health. Workers with severe pain symptoms had higher probabilities of benefit durations of 12-18 months (OR=9.35), higher lost-earnings costs (~47.7% higher) and higher healthcare expenditure costs at 18 months (~125.9% higher) compared with those with no pain symptoms.

CONCLUSIONS

Persistent pain symptom prevalence 18 months postinjury is high among workers disabled by a work-related injury and associated with substantial functional impairment and longer wage replacement benefit duration.

Duchenne muscular dystrophy trajectory in R-DMDdel52 preclinical rat model identifies COMP as biomarker of fibrosis

Duchenne muscular dystrophy (DMD) is a fatal muscle-wasting disorder caused by mutations in the Dystrophin gene and for which there is currently no cure. To bridge the gap between preclinical and therapeutic evaluation studies, we have generated a rat model for DMD that carries an exon 52 deletion (R-DMDdel52) causing a complete lack of dystrophin protein. Here we show that R-DMDdel52 animals recapitulated human DMD pathophysiological trajectory more faithfully than the mdx mouse model. We report that R-DMDdel52 rats displayed progressive and severe skeletal muscle loss associated with fibrotic deposition, fat infiltration and fibre type switch. Early fibrosis was also apparent in the cardiac muscle. These histological modifications led to severe muscle, respiratory and cardiac functional impairments leading to premature death around 1 year. Moreover, DMD muscle exhibited systemic inflammation with a mixed M1/M2 phenotype. A comparative single cell RNAseq analysis of the diaphragm muscle was performed, revealing cellular populations alteration and molecular modifications in all muscle cell types. We show that DMD fibroadipogenic progenitors produced elevated levels of cartilage oligomeric matrix protein, a glycoprotein responsible for modulating homeostasis of extracellular matrix, and whose increased concentration correlated with muscle fibrosis both in R-DMDdel52 rats and human patients. Fibrosis is a component of tissue remodelling impacting the whole musculature of DMD patients, at the tissue level but most importantly at the functional level. We therefore propose that this specific biomarker can optimize the prognostic monitoring of functional improvement of patients included in clinical trials.

Job requirements and physical demands (JRPD) questionnaire: cross-cultural adaptation and psychometric evaluation in Iranian Army personnel with chronic low back pain

BACKGROUND

Biomechanical risk factors have been identified as the main predisposing factor of chronic low back pain (CLBP), especially in Army personnel. The Job Requirements and Physical Demands (JRPD) questionnaire has been developed to assess the biomechanical exposures related to CLBP. Examining the biomechanical risk factors could prevent CLBP. This study aimed to translate and cross-culturally adapt the JRPD into Persian and assess its psychometric properties among Iranian male Army personnel with CLBP.

METHODS

In this cross-sectional study, the content validation of the JRPD was assessed after translating to Persian. The Persian JRPD was administered to 198 male Army personnel with CLBP, with an interval of 7 days, to assess test-retest reliability, including Cronbach's α, intraclass correlation coefficients (ICC), standard error of measurement (SEM), and minimal detectable change at 95% confidence interval (MDC_95%). Scores of the Persian JRPD were correlated with the scores of visual analog scale (VAS), Borg's category-ratio (CR10) scale, general health questionnaire-28 (GHQ-28), and physical functioning (PF₁ and PF₂) subscale of the 12-item short-form health survey (SF-12) to assess convergent validity using Spearman correlation for a priori hypotheses.

RESULTS

The Persian JRPD had good content validity evidenced by the higher content validity index (> 0.70). The questionnaire had a significant positive negligible to weak correlation with the VAS (rho = 0.27; p < 0.001), Borg's CR10 scale (rho = 0.19; p = 0.009), and the total score of GHQ-28 and its domains (rho ≤0.34; p < 0.05); and significant negative weak correlation with PF₂ (rho = - 0.27; p < 0.001) and significant negative moderate correlation with PF₁ (rho = - 0.35; p < 0.001), thus confirming the priori hypotheses (89%, 8/9). The internal consistency and ICC (α = 0.91; ICC = 0.80) were highly adequate, with SEM and MDC_95% of 7.91 and 21.3 respectively.

CONCLUSIONS

The JRPD was successfully adapted into Persian and had adequate psychometric properties in terms of content and convergent validity, internal consistency, and test-retest reliability. The questionnaire is found useable to assess the CLBP-related biomechanical exposures in Iranian male Army personnel.

Extensor carpi ulnaris muscle shows unexpected slow-to-fast fiber type switch in Duchenne muscular dystrophy dogs

Aged dystrophin-null canines are excellent models for studying experimental therapies for Duchenne muscular dystrophy, a lethal muscle disease caused by dystrophin deficiency. To establish the baseline, we studied the extensor carpi ulnaris (ECU) muscle in 15 terminal age (3-year-old) male affected dogs and 15 age/sex-matched normal dogs. Affected dogs showed histological and anatomical hallmarks of dystrophy, including muscle inflammation and fibrosis, myofiber size variation and centralized myonuclei, as well as a significant reduction of muscle weight, muscle-to-body weight ratio and muscle cross-sectional area. To rigorously characterize the contractile properties of the ECU muscle, we developed a novel in situ assay. Twitch and tetanic force, contraction and relaxation rate, and resistance to eccentric contraction-induced force loss were significantly decreased in affected dogs. Intriguingly, the time-to-peak tension and half-relaxation time were significantly shortened in affected dogs. Contractile kinetics predicted an unforeseen slow-to-fast myofiber-type switch, which we confirmed at the protein and transcript level. Our study establishes a foundation for studying long-term and late-stage therapeutic interventions in dystrophic canines. The unexpected myofiber-type switch highlights the complexity of muscle remodeling in dystrophic large mammals.

This article has an associated First Person interview with the first author of the paper.

Summary: A slow-to-fast fiber-type switch in dystrophic canine ECU muscle is revealed by contraction kinetics and myosin protein and transcript expression. This highlights the complexity of muscle remodeling in Duchenne muscular dystrophy.

Hands-Up program: protocol for a feasibility randomised controlled trial of a combined 6-week exercise and education intervention in adults aged 50-65 with a distal radius fracture

INTRODUCTION

This pilot study will determine the feasibility of recruitment, retention and adherence for the online combined exercise and education programme (Hands-Up) compared with usual care.

METHODS AND ANALYSIS

The proposed randomised controlled trial will be a pilot feasibility study with a 1:1 randomisation to the Hands-Up programme or usual physical therapy. The programme setting is an online home exercise and education program. Outcome assessments will take place at the Roth|McFarlane Hand and Upper Limb Clinic in London, Ontario, which is a tertiary care academic centre. 74 people aged 50-65 years after distal radius fracture will be recruited. Purposeful recruitment will be conducted to include a sufficient number of men in the study. The Hands-Up program includes both exercise and education. Participants will engage in approximately 45 min of a full-body home exercise routine followed by 30 min of education in an online program. The educational modules will focus on fall prevention, nutrition for osteoporosis and learning about osteoporosis. Participants will engage in the program online, twice a week for 6 weeks. Outcomes will be assessed at baseline, 6 weeks and 3, 6 and 12 months. The primary outcome of the study is feasibility. The study will be considered feasible if participants attend >60% of the sessions, 74 participants are enrolled in 12 months and >75% of participants attend the final study visit. For the secondary outcome, physical and self-report outcomes will be assessed.

ETHICS AND DISCUSSION

This study has been approved by the institutional ethics review board. The viability of an online exercise and education program for people after distal radius fracture between the ages of 50 and 65 will be evaluated in an attempt to help better prevent, diagnose and manage osteoporosis. This study will be disseminated through peer-reviewed publications, international conferences and social media.

TRIAL REGISTRATION NUMBER

NCT03997682.

Development of outcome measures according to dystrophic phenotypes in canine X-linked muscular dystrophy in Japan

Duchenne muscular dystrophy (DMD) is an X-linked lethal muscle disorder characterized by primary muscle degeneration. Therapeutic strategies for DMD have been extensively explored, and some are in the stage of human clinical trials. Along with the development of new therapies, sensitive outcome measures are needed to monitor the effects of new treatments. Therefore, we investigated outcome measures such as biomarkers and motor function evaluation in a dystrophic model of beagle dogs, canine X-linked muscular dystrophy in Japan (CXMD_J). Osteopontin (OPN), a myogenic inflammatory cytokine, was explored as a potential biomarker in dystrophic dogs over the disease course. The serum OPN levels of CXMD_J dystrophic dogs were elevated, even in the early disease phase, and this could be related to the presence of regenerating muscle fibers; as such, OPN would be a promising biomarker for muscle regeneration. Next, accelerometry, which is an efficient method to quantify performance in validated tasks, was used to evaluate motor function longitudinally in dystrophic dogs. We measured three-axis acceleration and angular velocity with wireless hybrid sensors during gait evaluations. Multiple parameters of acceleration and angular velocity showed notedly lower values in dystrophic dogs compared with wild-type dogs, even at the onset of muscle weakness. These parameters accordingly decreased with exacerbation of clinical manifestations along with the disease course. Multiple parameters also indicated gait abnormalities in dystrophic dogs, such as a waddling gait. These outcome measures could be applicable in clinical trials of patients with DMD or other muscle disorders.

Immortalized Canine Dystrophic Myoblast Cell Lines for Development of Peptide-Conjugated Splice-Switching Oligonucleotides

Duchenne muscular dystrophy (DMD) is a severe muscle-wasting disease caused by frameshift or nonsense mutations in the DMD gene, resulting in the loss of dystrophin from muscle membranes. Exon skipping using splice-switching oligonucleotides (SSOs) restores the reading frame of DMD pre-mRNA by generating internally truncated but functional dystrophin protein. To potentiate effective tissue-specific targeting by functional SSOs, it is essential to perform accelerated and reliable in vitro screening-based assessment of novel oligonucleotides and drug delivery technologies, such as cell-penetrating peptides, before their in vivo pharmacokinetic and toxicity evaluation. We have established novel canine immortalized myoblast lines by transducing murine cyclin-dependent kinase-4 and human telomerase reverse transcriptase genes into myoblasts isolated from beagle-based wild-type or canine X-linked muscular dystrophy in Japan (CXMDJ) dogs. These myoblast lines exhibited improved myogenic differentiation and increased proliferation rates compared with passage-15 primary parental myoblasts, and their potential to differentiate into myotubes was maintained in later passages. Using these dystrophin-deficient immortalized myoblast lines, we demonstrate that a novel cell-penetrating peptide (Pip8b2)-conjugated SSO markedly improved multiexon skipping activity compared with the respective naked phosphorodiamidate morpholino oligomers. In vitro screening using immortalized canine cell lines will provide a basis for further pharmacological studies on drug delivery tools.

Incidence of occupational injuries and diseases among seafarers: a descriptive epidemiological study based on contacts from onboard ships to the Italian Telemedical Maritime Assistance Service in Rome, Italy

OBJECTIVES

Workers at sea have high mortality, injuries and illnesses and work in a hazardous environment compared to ashore workers. The present study was designed to measure the incidence of occupational injuries and diseases among seafarers and quantify the contribution of differences in rank and job onboard on seafarers' diseases and injuries rates.

DESIGN

Descriptive epidemiological study.

SETTING AND PARTICIPANTS

This study's data were based on contacts (n=423) for medical requests from Compagnie Maritime d'Affrètement/Compagnie Générale Maritime (CMA-CGM) container ships to the Italian Telemedical Maritime Assistance Service in Rome from 2016 to 2019, supplemented by data on the estimated total at-risk seafarer population on container ships (n=13 475) over the study period.

OUTCOME MEASURES

Distribution of injuries by anatomic location and types of diseases across seafarers' ranks and worksites. We determined the incidence rate and incidence rate ratio (IRR) with a 95% CI.

RESULTS

The total disease rate was 25 per 1000 seafarer-years, and the overall injury rate was 6.31 per 1000 seafarer-years over the 4 years study period. Non-officers were more likely than officers to have reported gastrointestinal (IRR 2.12, 95% CI 1.13 to 4.26), dermatological (IRR 3.66, 95% CI 1.27 to 14.42) and musculoskeletal (IRR 2.25, 95% CI 1.11 to 5.05) disorders onboard container ships. Deck workers were more likely than engine workers to be injured in the wrist and hand (IRR 3.25, 95% CI 1.19 to 10.23).

CONCLUSIONS

Rates of reported injury and disease were significantly higher among non- officers than officers; thus, this study suggests the need for rank-specific preventative measures. Future studies should consider risk factors for injury and disease among seafarers in order to propose further preventive measures.

Myofascial release versus Mulligan sustained natural apophyseal glides' immediate and short-term effects on pain, function, and mobility in non-specific low back pain

Background

Myofascial release (MFR) and Mulligan Sustained Natural Apophyseal Glides (SNAGs) are manual therapy techniques routinely practiced in the management of non-specific low back pain (NSLBP). As a solo intervention or along with other therapies, both methods have reported positive results for individuals with NSLBP. However, which technique improves NSLBP-related pain, restricted range of motion (ROM) and disability, warrants further research.

Objective

To study the comparative effects of MFR and SNAGs on pain, disability, functional ability, and lumbar ROM in NSLBP.

Method

A parallel-group study was conducted at tertiary care hospitals. Sixty-five Sub-acute or chronic NSLBP patients were allocated to receive strengthening exercises along with either MFR (n = 33) or SNAGs (n = 32) for six treatment sessions over one week. An independent assessor evaluated outcome measures such as the Visual Analog Scale (VAS), Patient-Specific Function Scale (PSFS), and ROM at baseline, immediate (after 1st treatment), and short-term (post-sixth day of the intervention). The Modified Oswestry disability index (MODI) was assessed at baseline and short-term.

Results

Within-group analysis found clinically and statistically significant (p < 0.05) changes for VAS and PSFS at immediate and short-term for both the groups. The lumbar extension also showed improvement immediately and in the short-term. Improvement in Lumbar flexion was seen only in the SNAGs group over the short-term. A statistically significant improvement was seen for MODI in both the groups but was not clinically significant in the MFR group. The analysis observed no statistically significant difference (p < 0.05) between the groups at both the immediate and short-term.

Conclusions

Pain and restricted function associated with NSLBP can be improved using SNAGs or MFR, along with strengthening exercises. For limited lumbar flexion ROM, Mulligan SNAGs have a better outcome than MFR over the short-term. Hence, both manual therapy techniques can be incorporated along with exercises for immediate and short-term management of sub-acute to chronic NSLBP.

Clinical Trial Registration. CTRI/2018/12/016787 (http://ctri.nic.in/Clinicaltrials/).

Elevation of fast but not slow troponin I in the circulation of patients with Becker and Duchenne muscular dystrophy

Introduction

One of the hallmarks of injured skeletal muscle is the appearance of elevated skeletal muscle proteins in circulation. Human skeletal muscle generally consists of a mosaic of slow (type I) and fast (type IIa, IIx/d) fibers, defined by their myosin isoform expression. Recently, measurement of circulating fiber‐type specific isoforms of troponin I has been used as a biomarker to suggest that muscle injury in healthy volunteers (HV) results in the appearance of muscle proteins from fast but not slow fibers. We sought to understand if this is also the case in severe myopathy patients with Becker and Duchenne muscular dystrophy (BMD, DMD).

Methods

An enzyme‐linked immunosorbent assay (ELISA) that selectively measures fast and slow skeletal troponin I (TNNI2 and TNNI1) was used to measure a cross‐section of patient plasma samples from HV (N = 50), BMD (N = 49), and DMD (N = 132) patients. Creatine kinase (CK) activity was also measured from the same samples for comparison.

Results

TNNI2 was elevated in BMD and DMD and correlated with the injury biomarker, CK. In contrast, TNNI1 levels were indistinguishable from levels in HV. There was an inverse relationship between CK and TNNI2 levels and age, but no relationship for TNNI1.

Discussion

We define a surprising discrepancy between TNNI1 and TNNI2 in patient plasma that may have implications for the interpretation of elevated muscle protein levels in dystrophinopathies.

See Editorial on pages 4–5 in this issue.

Clinical and cost-effectiveness of physiotherapy interventions following total knee replacement: a systematic review and meta-analysis

PURPOSE

Osteoarthritis is the single most common cause of pain and disability in older adults. This review addresses the question of the clinical effectiveness and cost-effectiveness of physiotherapy interventions following total knee replacement (TKR).

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. MEDLINE, CINAHL, AMED, DARE, HTA and NHS EED databases were searched from inception to 02 May 2020. Search terms related to the clinical and cost-effectiveness of physiotherapy interventions were used. Studies meeting the inclusion criteria were identified and key data were extracted. Random effect meta-analysis was conducted for pain, physical function and range of motion (ROM).

RESULTS

In total, 1467 studies were identified. Of these, 26 studies were included; methodological quality of most studies was adequate. Physiotherapy interventions were more effective than control for function, SMD - 0.166 [95% Confidence Interval (CI) - 0.420 to 0.088.] and ROM, SMD - 0.219 [95% CI - 0.465 to 0.028] for a follow-up of 2 or 3 months. Patients in the intervention group showed improvement in pain at 12-13 weeks, SMD - 0.175 [95% CI - 0.416 to 0.067]. No evidence on the pooled estimate of cost-effectiveness of physiotherapy interventions was found.

CONCLUSIONS

This is the first systematic review and meta-analysis that has examined the clinical and cost-effectiveness of physiotherapy interventions following TKR. The findings of this review suggest that physiotherapy interventions were effective for improving physical function, ROM and pain in a short-term follow-up following TKR. Insufficient evidence exists to establish the benefit of physiotherapy in the long term for patient with TKR. Further study should examine the long-term effectiveness and cost-effectiveness of physiotherapy interventions.

Validity of increasing the number of motor control tests within a test battery for discrimination of low back pain conditions in people attending a physiotherapy clinic: a case-control study

OBJECTIVES

To develop a time-efficient motor control (MC) test battery while maximising diagnostic accuracy of both a two-level and three-level classification system for patients with non-specific low back pain (LBP).

DESIGN

Case-control study.

SETTING

Four private physiotherapy practices in northern Germany.

PARTICIPANTS

Consecutive males and females presenting to a physiotherapy clinic with non-specific LBP (n=65) were compared with 66 healthy-matched controls.

PRIMARY OUTCOME MEASURES

Accuracy (sensitivity, specificity, Youden index, positive/negative likelihood ratio, area under the curve (AUC)) of a clinically driven consensus-based test battery including the ideal number of test items as well as threshold values and most accurate items.

RESULTS

For both the two and three-level categorisation system, the ideal number of test items was 10. With increasing number of failed tests, the probability of having LBP increases. The overall discrimination potential for the two-level categorisation system of the test is good (AUC=0.85) with an optimal cut-off of three failed tests. The overall discrimination potential of the three-level categorisation system is fair (volume under the surface=0.52). The optimal cut-off for the 10-item test battery for categorisation into none, mild/moderate and severe MC impairment is three and six failed tests, respectively.

CONCLUSION

A 10-item test battery is recommended for both the two-level (impairment or not) and three-level (none, mild, moderate/severe) categorisation of patients with non-specific LBP.

Accelerometric outcomes of motor function related to clinical evaluations and muscle involvement in dystrophic dogs

Duchenne muscular dystrophy (DMD) is an X-linked muscle disorder characterized by primary muscle degeneration. Patients with DMD reveal progressive muscle weakness leading to ambulatory dysfunction. Novel outcome measures are needed for more sensitive evaluation of therapeutic effects in clinical trials. Multiple parameters of acceleration and angular velocity are used as efficient indicators to quantify the motion of subjects, and these parameters have been recently applied for evaluation of motor function in DMD. In the present study, we evaluated gait in a dystrophic dog model, CXMDJ, by measuring three-axial acceleration and angular velocity over the course of months. Hybrid sensors were placed on the dorsal thoracic and lumbar regions of dogs to detect a wide range of acceleration (±8 G) and angular velocity (±1000 degrees per second). Multiple parameters showed lower values in dystrophic dogs compared to wild-type (WT) dogs, and declined over the course of months. Acceleration magnitude (AM) at the thoracic region in dystrophic dogs was prominently lower compared with WT dogs, even at the age of 2 months, the onset of muscle weakness, whereas AM at the lumbar region drastically declined throughout the disease course. The angular velocity index in the vertical direction in the lumbar region increased in dystrophic dogs, suggesting waddling at the girdle. These parameters also accordingly decreased with exacerbation of clinical manifestations and a decrease in spontaneous locomotor activity. The AM of dystrophic dogs was analyzed with magnetic resonance imaging to look for a correlation with crus muscle involvement. Results showed that acceleration and angular velocity are multifaceted kinematic indices that can be applied to assess outcomes in clinical trials for hereditary neuromuscular disorders including DMD.

Influence of rearfoot alignment on static and dynamic postural stability

Background/Aims:

It has been postulated that foot alignment affects postural stability. However, previous studies reported contradicting results regarding the association between foot alignment and postural stability.

Methods:

A total of 216 healthy participants aged 15 to 24 years were recruited. Their rearfoot alignment was measured in non-weight bearing and weight-bearing positions. Their static balance was assessed using Balance Error Scoring System and dynamic balance by Star Excursion Balance Test. The relationship between the data obtained were analysed using SPSS version 22 software.

Findings:

A Pearson correlation with a 95% confidence interval reported that there was: (i) no significant difference in the rearfoot alignment between both genders; (ii) no significant relationship between the rearfoot alignment measured in prone lying and unilateral stance position; (iii) a weak negative correlation between the rearfoot alignment measured in prone lying position to dynamic balance on medial, posterior, lateral, anterolateral and posteromedial direction; (iv) no significant relationship between the rearfoot alignment measured in unilateral stance position to both static and dynamic postural balance.

Conclusions:

Rearfoot alignment measured in non-weight bearing position plays some role in postural stability and therefore should be considered in sports rehabilitation. However, this can be overlooked in rehabilitation for individuals whose postural stability is not the primary concern.

Identification of sleep hypoventilation in young individuals with Becker muscular dystrophy: A pilot study

AIM

To report on sleep hypercapnia in Becker muscular dystrophy (BMD) at earlier stages than ever recognized.

SUBJECTS AND METHODS

This retrospective study examined nocturnal hypercapnia in six young Becker muscular dystrophy (BMD) patients with deletions of one or more exons of DMD gene. Clinical information, consecutive data on forced vital capacity (FVC%), forced expiratory volume in one second (FEV1%), peak expiratory flow (PEF%), peak cough flow (PCF), average PCO₂ in all-night monitoring, and left ventricular ejection fraction (LVEF) were reviewed.

RESULTS

In five BMD patients, including three who were still ambulant, nocturnal average PCO₂ was elevated to >45 mmHg at 12-31 years of age. Noninvasive positive pressure ventilation was initiated in four patients. Gradual declines in FVC% and PEF% were evident in one BMD patient with exon 3-7 deletion, whereas these functions did not change in the remaining BMD patients. PCF, FEV1%, and LVEF were less informative for the assessment of respiratory function in this patient series.

CONCLUSION

Sleep hypercapnia was present in certain BMD patients, which was unexpected from the routine pulmonary function tests. Individualized assessment of nocturnal PCO₂, partly based on the deletion types, should be further explored in the clinical practice of BMD patients.

Changes in Muscle Metabolism are Associated with Phenotypic Variability in Golden Retriever Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an X-chromosome-linked disorder and the most common monogenic disease in people. Affected boys are diagnosed at a young age, become non-ambulatory by their early teens, and succumb to cardiorespiratory failure by their thirties. Despite being a monogenic condition resulting from mutations in the DMD gene, affected boys have noteworthy phenotypic variability. Efforts have identified genetic modifiers that could modify disease progression and be pharmacologic targets. Dogs affected with golden retriever muscular dystrophy (GRMD) have absent dystrophin and demonstrate phenotypic variability at the functional, histopathological, and molecular level. Our laboratory is particularly interested in muscle metabolism changes in dystrophin-deficient muscle. We identified several metabolic alterations, including myofiber type switching from fast (type II) to slow (type I), reduced glycolytic enzyme expression, reduced and morphologically abnormal mitochondria, and differential AMP-kinase phosphorylation (activation) between hypertrophied and wasted muscle. We hypothesize that muscle metabolism changes are, in part, responsible for phenotypic variability in GRMD. Pharmacological therapies aimed at modulating muscle metabolism can be tested in GRMD dogs for efficacy.

Group-based exercise at workplace: short-term effects of neck and shoulder resistance training in video display unit workers with work-related chronic neck pain-a pilot randomized trial

Effectiveness of exercise therapy in video display unit (VDU) workers with work-related chronic neck pain (W-RCNP) is unclear. The aim of the study was to assess the efficacy of group-based neck-shoulder resistance exercises on symptoms and muscular function in VDU workers with W-RCNP. Thirty-five employees with CNP were randomly assigned to neck-shoulder resistance exercise (NSRE) group or to conventional stretching and postural exercise (SPE) group. Participants trained 45 min, twice a week for 7 weeks. Primary outcomes were pain intensity (0-10 numeric rating scale, NRS) and pain-related disability (Vernon Neck Disability Index, NDI). Secondary outcomes were cervical active range of motion (AROM), endurance of neck flexors, strength of shoulder abductors, and health-related quality of life (SF-36). Post-treatment, pain and disability decreased 2.5 and 5 points in NSRE (p = 0.001) and 5 and 8 points in SPE (p = 0.002), with no significant differences between groups. AROM improved significantly in both groups; between-group differences were not significant. Neck flexors endurance and shoulder abductors strength improved by 59.6 and 34.2% (p = 0.001) in the NSRE group and by 27.6% (p = 0.009) and 2.3% (p = 0.002) in the SPE group; between-group differences were significant (p = 0.016 and p < 0.001, respectively). SF-36 score remained unchanged. NSRE and SPE are feasible and equally effective in reducing pain and pain-related disability as group exercises in W-RCNP. NSRE may provide some advantage in improving strength and endurance in neck muscles. Further, larger studies should confirm these findings and assess whether a better muscle function confers long-term clinical advantages.

Anatomical and mesoscopic characterization of the dystrophic diaphragm: An in vivo nuclear magnetic resonance imaging study in the Golden retriever muscular dystrophy dog

Because respiratory failure remains a major issue in Duchenne Muscular Dystrophy patients, respiratory muscles are a key target of systemic therapies. In the Golden Retriever Muscular Dystrophy (GRMD) dogs, the disease shows strong clinical and histological similarities with the human pathology, making it a valuable model for preclinical therapeutic trials. We report here the first nuclear magnetic resonance (NMR) imaging anatomical study of the diaphragm in GRMD dogs and healthy controls. Both T1- and T2-weighted images of the diaphragm of seven healthy and thirteen GRMD dogs, from 3 to 36 months of age, were acquired on a 3 tesla NMR scanner. Abnormalities of texture and shape were revealed and consisted of increases in signal intensity on T2-weighted images and in signal heterogeneity on both T1- and T2-weighted images of the dystrophic diaphragm. These abnormalities were associated with a significant thickening of the muscle and we identified a clear 8-mm-threshold distinguishing clinically preserved GRMD dogs from those more severely affected. In this study, we demonstrated the feasibility of NMR imaging of the diaphragm and depicted several anatomical and mesoscopic anomalies in the dystrophic diaphragm. NMR imaging of the diaphragm shows a promise as an outcome measure in preclinical trials using GRMD dogs.

Laser and LED phototherapy on midpalatal suture after rapid maxilla expansion: Raman and histological analysis

The aim of this study was to analyze the effect of laser or LED phototherapy on the acceleration of bone formation at the midpalatal suture after rapid maxilla expansion. Forty-five rats were divided into groups at 7 days (control, expansion, expansion and laser irradiation, and expansion and LED irradiation) and into 14 days (expansion, expansion and laser in the 1st week, expansion and LED in the 1st week, expansion and laser in the 1st and 2nd weeks, expansion and LED in the 1st and 2nd weeks). Laser/LED irradiation occurred every 48 h. Expansion was accomplished with a spatula and maintained with a triple helicoid of 0.020-in stainless steel orthodontic wire. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm², t = 257 s, SAEF of 18 J/cm²) or a LED (λ850 ± 10 nm, 150 ± 10 mW, spot of 0.5 cm², t = 120 s, SAEF of 18 J/cm²) was applied in one point in the midpalatal suture immediately behind the upper incisors. Raman spectroscopy and histological analyses of the suture region were carried and data was submitted to statistical analyses (p ≤ 0.05). Raman spectrum analysis demonstrated that irradiation increases hydroxyapatite in the midpalatal suture after expansion. In the histological analysis of various inflammation, there was a higher production of collagen and osteoblastic activity and less osteoclastic activity. The results showed that LED irradiation associated to rapid maxillary expansion improves bone repair and could be an alternative to the use of laser in accelerating bone formation in the midpalatal suture.

Influence of Botulinumtoxin A on the Expression of Adult MyHC Isoforms in the Masticatory Muscles in Dystrophin-Deficient Mice (Mdx-Mice)

The most widespread animal model to investigate Duchenne muscular dystrophy is the mdx-mouse. In contrast to humans, phases of muscle degeneration are replaced by regeneration processes; hence there is only a restricted time slot for research. The aim of the study was to investigate if an intramuscular injection of BTX-A is able to break down muscle regeneration and has direct implications on the gene expression of myosin heavy chains in the corresponding treated and untreated muscles. Therefore, paralysis of the right masseter muscle was induced in adult healthy and dystrophic mice by a specific intramuscular injection of BTX-A. After 21 days the mRNA expression and protein content of MyHC isoforms of the right and left masseter, temporal, and the tongue muscle were determined using quantitative RT-PCR and Western blot technique. MyHC-IIa and MyHC-I-mRNA expression significantly increased in the paralyzed masseter muscle of control-mice, whereas MyHC-IIb and MyHC-IIx/d-mRNA were decreased. In dystrophic muscles no effect of BTX-A could be detected at the level of MyHC. This study suggests that BTX-A injection is a suitable method to simulate DMD-pathogenesis in healthy mice but further investigations are necessary to fully analyse the BTX-A effect and to generate sustained muscular atrophy in mdx-mice.

The PLE(2)NO self-management and exercise program for knee osteoarthritis: Study Protocol for a Randomized Controlled Trial

Background

International recommendations suggest exercise and self-management programs, including non-pharmacological treatments, for knee osteoarthritis (KOA) because they can benefit pain relief and improve function and exercise adherence. The implementation of a combined self-management and exercise program termed PLE²NO may be a good method for controlling KOA symptoms because it encourages the development of self-efficacy to manage the pathology. This study will assess the effects of a self-management and exercise program in comparison to an educational intervention (control program) on symptoms, physical fitness, health-related quality of life, self-management behaviors, self-efficacy, physical activity level and coping strategies.

Methods/Design

This PLE²NO study is a single-blinded, randomized controlled trial of elderly (aged above 60 yrs old) patients with clinical and radiographic KOA. The patients will be allocated into either an educational group (control) or a self-management and exercise group (experimental). All participants will receive a supplement of chondroitin and glucosamine sulfates. This paper describes the protocol that will be used in the PLE²NO program.

Discussion

This program has several strengths. First, it involves a combination of self-management and exercise approaches, is available in close proximity to the patients and occurs over a short period of time. The latter two characteristics are crucial for maintaining participant adherence. Exercise components will be implemented using low-cost resources that permit their widespread application. Moreover, the program will provide guidance regarding the effectiveness of using a self-management and exercise program to control KOA symptoms and improve self-efficacy and health-related quality of life.

Trial registration

NCT02562833 (09/23/2015)

Skeletal muscle fiber type: using insights from muscle developmental biology to dissect targets for susceptibility and resistance to muscle disease

Skeletal muscle fibers are classified into fiber types, in particular, slow twitch versus fast twitch. Muscle fiber types are generally defined by the particular myosin heavy chain isoforms that they express, but many other components contribute to a fiber's physiological characteristics. Skeletal muscle fiber type can have a profound impact on muscle diseases, including certain muscular dystrophies and sarcopenia, the aging-induced loss of muscle mass and strength. These findings suggest that some muscle diseases may be treated by shifting fiber type characteristics either from slow to fast, or fast to slow phenotypes, depending on the disease. Recent studies have begun to address which components of muscle fiber types mediate their susceptibility or resistance to muscle disease. However, for many diseases it remains largely unclear why certain fiber types are affected. A substantial body of work has revealed molecular pathways that regulate muscle fiber type plasticity and early developmental muscle fiber identity. For instance, recent studies have revealed many factors that regulate muscle fiber type through modulating the activity of the muscle regulatory transcription factor MYOD1. Future studies of muscle fiber type development in animal models will continue to enhance our understanding of factors and pathways that may provide therapeutic targets to treat muscle diseases. WIREs Dev Biol 2016, 5:518-534. doi: 10.1002/wdev.230 For further resources related to this article, please visit the WIREs website.

Serum Osteopontin as a Novel Biomarker for Muscle Regeneration in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is a lethal X-linked muscle disorder. We have already reported that osteopontin (OPN), an inflammatory cytokine and myogenic factor, is expressed in the early dystrophic phase in canine X-linked muscular dystrophy in Japan, a dystrophic dog model. To further explore the possibility of OPN as a new biomarker for disease activity in Duchenne muscular dystrophy, we monitored serum OPN levels in dystrophic and wild-type dogs at different ages and compared the levels to other serum markers, such as serum creatine kinase, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinase-1. Serum OPN levels in the dystrophic dogs were significantly elevated compared with those in wild-type dogs before and 1 hour after a cesarean section birth and at the age of 3 months. The serum OPN level was significantly correlated with the phenotypic severity of dystrophic dogs at the period corresponding to the onset of muscle weakness, whereas other serum markers including creatine kinase were not. Immunohistologically, OPN was up-regulated in infiltrating macrophages and developmental myosin heavy chain-positive regenerating muscle fibers in the dystrophic dogs, whereas serum OPN was highly elevated. OPN expression was also observed during the synergic muscle regeneration process induced by cardiotoxin injection. In conclusion, OPN is a promising biomarker for muscle regeneration in dystrophic dogs and can be applicable to boys with Duchenne muscular dystrophy.

[Bone marrow edema and joint injuries]

BACKGROUND

The development of bone marrow edema in body regions adjacent to joints can have many causes and a differentiation is not possible using magnetic resonance imaging (MRI).

DEFINITION

Bone marrow edema is not necessarily an indication for microfractures. The definition of bone marrow edema is a purely radiological description. There is no uniform classification of bone marrow edema. The clinical significance, therapy and course are heterogeneous; therefore, there are no uniform recommendations for therapy.

DIAGNOSTICS

A bone marrow edema visible in MRI does not always lead to certain inferences regarding the pathogenesis. In order to be able to detect fractures it is necessary to carry out a biopsy and a histological examination.

CONCLUSION

The interpretation of MRI results and the derivation of a therapy in every case need a balanced assessment of the MRI results, medical history, clinical investigations and clinical symptoms.

Individual and work-related risk factors for musculoskeletal pain: a cross-sectional study among Estonian computer users

Background

Occupational use of computers has increased rapidly over recent decades, and has been linked with various musculoskeletal disorders, which are now the most commonly diagnosed occupational diseases in Estonia. The aim of this study was to assess the prevalence of musculoskeletal pain (MSP) by anatomical region during the past 12 months and to investigate its association with personal characteristics and work-related risk factors among Estonian office workers using computers.

Methods

In a cross-sectional survey, the questionnaires were sent to the 415 computer users. Data were collected by self-administered questionnaire from 202 computer users at two universities in Estonia. The questionnaire asked about MSP at different anatomical sites, and potential individual and work related risk factors. Associations with risk factors were assessed by logistic regression.

Results

Most respondents (77%) reported MSP in at least one anatomical region during the past 12 months. Most prevalent was pain in the neck (51%), followed by low back pain (42%), wrist/hand pain (35%) and shoulder pain (30%). Older age, right-handedness, not currently smoking, emotional exhaustion, belief that musculoskeletal problems are commonly caused by work, and low job security were the statistically significant risk factors for MSP in different anatomical sites.

Conclusions

A high prevalence of MSP in the neck, low back, wrist/arm and shoulder was observed among Estonian computer users. Psychosocial risk factors were broadly consistent with those reported from elsewhere. While computer users should be aware of ergonomic techniques that can make their work easier and more comfortable, presenting computer use as a serious health hazard may modify health beliefs in a way that is unhelpful.

Fibre type-specific satellite cell content in two models of muscle disease

AIMS

Muscle satellite cells (SCs) are responsible for the regenerative events following muscle fibre injury. This study aimed to improve our understanding of SC behaviour in two models of muscle disorder with different pathological mechanisms and onset of disease.

METHODS AND RESULTS

Pax7(+) SC content was assessed in types I and II fibres of patients with Duchenne muscular dystrophy (DMD; n = 9; age 13 ± 2 years), polymyositis/dermatomyositis (PM/DM; n = 9; age 52 ± 12 years) and in controls (n = 5; age 26 ± 5 years). Pax7(+) SCs number in type I and II fibres was higher (P < 0.05) in DMD and in PM/DM compared to controls. Type I fibres were associated with a higher number of Pax7(+) SCs compared to type II fibres only in DMD; Pax7(+) SCs number in type I fibres was about threefold higher in DMD compared to PM/DM (P < 0.05). In DMD, Pax7(+) SC content in small regenerating fibres (0.09 ± 0.09 SCs/fibre) was similar to that in fibres from healthy skeletal muscle. The proportion of activated SCs (Ki-67(+) SCs) was fivefold lower in DMD (0.4 ± 0.4%) compared to PM/DM (2.8 ± 2%). Pax7(+) cells located outside the basal lamina were observed in DMD muscles only.

CONCLUSION

The capacity to generate new SCs is increased even in severely impaired muscles and a fibre type-specific enhancement of SC occurs in type I muscle fibres in DMD.

Systematic review of contracture reduction in the lower extremity with dynamic splinting

Introduction

Joint contractures are relatively common disorders that can result in significant, long-term morbidity. Initial treatment is non-operative and often entails the use of mechanical modalities such as dynamic and static splints. Although widely utilized, there is a paucity of data that support the use of such measures. The purpose of this systematic review was to evaluate the safety and efficacy of dynamic splinting as it is used to treat joint contracture in lower extremities, and to determine if duration on total hours of stretching had an effect on outcomes.

Methods

Reviews of PubMed, Science Direct, Medline, AMED, and EMBASE websites were conducted to identify the term ‘contracture reduction’ in manuscripts published from January 2002 to January 2012. Publications selected for inclusion were controlled trials, cohort studies, or case series studies employing prolonged, passive stretching for lower extremity contracture reduction. A total of 354 abstracts were screened and eight studies (487 subjects) met the inclusion criteria. The primary outcome measure was change in active range of motion (AROM).

Results

The mean aggregate change in AROM was 23.5º in the eight studies examined. Dynamic splinting with prolonged, passive stretching as home therapy treatment showed a significant direct, linear correlation between the total number of hours in stretching and restored AROM. No adverse events were reported.

Discussion

Dynamic splinting is a safe and efficacious treatment for lower extremity joint contractures. Joint specific stretching protocols accomplished greater durations of end-range stretching which may be considered to be responsible for connective tissue elongation.

Fat infiltration in the lumbar multifidus and erector spinae muscles in subjects with sway-back posture

AIM

Decreased activity of the lumbar stabilizer muscles has been identified in individuals with sway-back posture. Disuse can predispose these muscles to atrophy, which is characterized by a reduced cross-sectional area (CSA) and by fat infiltration. The aim of this study was to evaluate the amount of fat infiltration in the lumbar multifidus and lumbar erector spinae muscles as a sign of the muscle atrophy in individuals with sway-back posture, with and without low back pain.

MATERIALS AND METHODS

Forty-five sedentary individuals between 16 and 40 years old participated in this study. The sample was divided into three groups: symptomatic sway-back (SSBG) (n = 15), asymptomatic sway-back (ASBG) (n = 15), and control (CG) (n = 15). The individuals were first subjected to photographic analysis to classify their postures and were then referred for a magnetic resonance imaging (MRI) examination of the lumbar spine. The total (TCSA) and functional (FCSA) cross-sectional areas of the lumbar erector spinae together with lumbar multifidus and isolated lumbar multifidus muscles were measured from L1 to S1. The amount of fat infiltration was estimated as the difference between the TCSA and the FCSA.

RESULTS

Greater fat deposition was observed in the lumbar erector spinae and lumbar multifidus muscles of the individuals in the sway-back posture groups than in the control group. Pain may have contributed to the difference in the amount of fat observed in the groups with the same postural deviation. Similarly, sway-back posture may have contributed to the tissue substitution relative to the control group independently of low back pain.

CONCLUSIONS

The results of this study indicate that individuals with sway-back posture may be susceptible to morphological changes in their lumbar erector spinae and lumbar multifidus muscles, both due to the presence of pain and as a consequence of their habitual posture.

Validity evidence of the Lateral Step Up (LSU) test for adolescents with spastic cerebral palsy

PURPOSE

The present study examined the concurrent and construct validity of the Lateral Step Up (LSU) test, for adolescents with CP.

METHOD

A total of 35 adolescents, classified as GMFCS Levels I, II and III, were examined using LSU, GMFM - 88 (D & E), other functional mobility measures (TUG, STS, TUDS), body structures and functions (strength, ROM and spasticity).

RESULTS

LSU inter-correlations with: (i) GMFM - 88 (D & E) (r = 0.656), (ii) functional mobility measures (r = -0.567 to 0.721) and (iii) body structures and functions (r = 0.155 to 0.563) were at the appropriate range. The LSU differentiated adolescents with CP (F = 16.185, p = 0.000, η(2) = 0.503), according to their GMFCS (I > II, II > III, I > III). Finally, 50.27% of the LSU variability was explained by GMFCS differences, with 65.7% of adolescents classified correctly across the three levels.

CONCLUSIONS

The LSU may be perceived as a valid instrument for assessing the functional mobility of adolescents with CP.

IMPLICATIONS FOR REHABILITATION

• LSU is valid for assessing functional mobility and strength in CP adolescents. • LSU may be used in accordance with other functional mobility measures in the school environment. • The LSU may be used from physical therapists to predict the functional mobility of CP adolescents at GMFCS Levels I–III.

Mouse fukutin deletion impairs dystroglycan processing and recapitulates muscular dystrophy

Dystroglycan is a transmembrane glycoprotein that links the extracellular basement membrane to cytoplasmic dystrophin. Disruption of the extensive carbohydrate structure normally present on α-dystroglycan causes an array of congenital and limb girdle muscular dystrophies known as dystroglycanopathies. The essential role of dystroglycan in development has hampered elucidation of the mechanisms underlying dystroglycanopathies. Here, we developed a dystroglycanopathy mouse model using inducible or muscle-specific promoters to conditionally disrupt fukutin (Fktn), a gene required for dystroglycan processing. In conditional Fktn-KO mice, we observed a near absence of functionally glycosylated dystroglycan within 18 days of gene deletion. Twenty-week-old KO mice showed clear dystrophic histopathology and a defect in glycosylation near the dystroglycan O-mannose phosphate, whether onset of Fktn excision driven by muscle-specific promoters occurred at E8 or E17. However, the earlier gene deletion resulted in more severe phenotypes, with a faster onset of damage and weakness, reduced weight and viability, and regenerating fibers of smaller size. The dependence of phenotype severity on the developmental timing of muscle Fktn deletion supports a role for dystroglycan in muscle development or differentiation. Moreover, given that this conditional Fktn-KO mouse allows the generation of tissue- and timing-specific defects in dystroglycan glycosylation, avoids embryonic lethality, and produces a phenotype resembling patient pathology, it is a promising new model for the study of secondary dystroglycanopathy.

Effects of nonlinearity in the materials used for the semi-rigid pedicle screw systems on biomechanical behaviors of the lumbar spine after surgery

Recently, various types of semi-rigid pedicle screw fixation systems have been developed for the surgical treatment of the lumbar spine. They were introduced to address the adverse issues commonly found in traditional rigid spinal fusion--abnormally large motion at the adjacent level and subsequent degeneration. The semi-rigid system uses more compliant materials (nitinol or polymers) and/or changes in rod design (coiled or twisted rods) as compared to the conventional rigid straight rods made of Ti alloys (E = 114 GPa, υ = 0.32). However, biomechanical studies on the semi-rigid pedicle screw systems were usually limited to linear modeling of the implant and anatomic elements, which may not be capable of reflecting realistic post-operative motions of the spine. In this study, we evaluated the effects of nonlinearity in materials used for semi-rigid pedicle screw fixation systems to evaluate the changes in biomechanical behaviors using finite element analysis. Changes in range of motion (ROM) and center of rotation (COR) were assessed at the operated and adjacent levels. Actual load-displacement results of the semi-rigid rod from mechanical test were carried out to reflect the nonlinearity of the implant. In addition, nonlinear material properties of various spinal ligaments studies were used for the finite element modeling. The post-operative models were constructed by modifying the previously validated intact model of the L1-S1 spine. Eight different post-operative models were made to address the effects of nonlinearity-with a traditional stiffness modulus rod (with linear ligaments, case 1; with nonlinear ligaments, case 5), with a rigid rod (with linear ligaments, case 2; with nonlinear ligaments, case 6), with a soft rod (with linear ligaments, case 3; with nonlinear ligaments, case 7), and with a nonlinear rod (with linear ligaments, case 4; with nonlinear ligaments, case 8). To simulate the load on the lumbar spine in a neutral posture, follower load (400 N) was applied and then the hybrid loading condition was applied to measure the ROM and COR in the sagittal plane. The more the nonlinearity was included in the model the closer the motion behavior of the device was to that of the intact spine. Furthermore, our results showed that the nonlinearity of the semi-rigid rod was a more sensitive factor than the nonlinearity of the spinal ligaments on biomechanical behavior of the lumbar spine after surgery. Therefore, for better understanding of the surgical effectiveness of the spinal device, more realistic material properties such as nonlinearity of the device and anatomic elements should be considered. In particular, the nonlinear properties of the semi-rigid rod were considered more than the nonlinearity of spinal ligaments.

Proteomic assessment of the acute phase of dystrophin deficiency in mdx mice

Duchenne muscular dystrophy (DMD) is caused by the absence of a functional dystrophin protein and is modeled by the mdx mouse. The mdx mouse suffers an early necrotic bout in the hind limb muscles lasting from approximately 4 to 7 weeks. The purpose of this investigation was to determine the extent to which dystrophin deficiency changed the proteome very early in the disease process. In order to accomplish this, proteins from gastrocnemius from 6-week-old C57 (n = 6) and mdx (n = 6) mice were labeled with fluorescent dye and subjected to two-dimensional differential in-gel electrophoresis (2D-DIGE). Resulting differentially expressed spots were excised and protein identity determined via MALDI-TOF followed by database searching using MASCOT. Proteins of the immediate energy system and glycolysis were generally down-regulated in mdx mice compared to C57 mice. Conversely, expression of proteins involved in the Kreb's cycle and electron transport chain were increased in dystrophin-deficient muscle compared to control. Expression of cytoskeletal components, including tubulins, vimentin, and collagen, were increased in mdx mice compared to C57 mice. Importantly, these changes are occurring at only 6 weeks of age and are caused by acute dystrophin deficiency rather than more chronic injury. These data may provide insight regarding early pathologic changes occurring in dystrophin-deficient skeletal muscle.

Establishment of a protocol for obtention of neuronal stem cells lineages from the dog olfactory epithelium

A morphological and cell culture study from nasal mucosa of dogs was performed in order to establish a protocol to obtain a cell population committed to neuronal lineage, as a proposal for the treatment of traumatic and degenerative lesions in these animals, so that in the future these results could be applied to the human species. Twelve mongrel dogs of 60-day aged pregnancy were collected from urban pound dogs in São Paulo. Tissue from cribriform ethmoidal lamina of the fetuses was collected at necropsy under sterile conditions around 1h to 2h postmortem by uterine sections and sections from the fetal regions described above. Isolated cells of this tissue were added in DMEM/F-12 medium under standard conditions of incubation (5% CO², >37ºC). Cell culture based on isolated cells from biopsies of the olfactory epithelium showed rapid growth when cultured for 24 hours, showing phase-bright sphere cells found floating around the fragments, attached on culture flasks. After 20 days, a specific type of cells, predominantly ellipsoids or fusiform cells was characterized in vitro. The indirect immunofluorescence examination showed cells expressing markers of neuronal precursors (GFAP, neurofilament, oligodendrocyte, and III â-tubulin). The cell proliferation index showed Ki67 immunostaining with a trend to label cell groups throughout the apical region, while PCNA immunostaining label predominantly cell groups lying above the basal lamina. The transmission electron microscopy from the olfactory epithelium of dogs revealed cells with electron-dense cytoplasm and preserving the same distribution as those of positive cell staining for PCNA. Metabolic activity was confirmed by presence of euchromatin in the greatest part of cells. All these aspects give subsidies to support the hypothesis about resident progenitor cells among the basal cells of the olfactory epithelium, committed to renewal of these cell populations, especially neurons.

Effect of obesity and low back pain on spinal mobility: a cross sectional study in women

BACKGROUND

obesity is nowadays a pandemic condition. Obese subjects are commonly characterized by musculoskeletal disorders and particularly by non-specific chronic low back pain (cLBP). However, the relationship between obesity and cLBP remains to date unsupported by an objective measurement of the mechanical behaviour of the spine and its morphology in obese subjects. Such analysis may provide a deeper understanding of the relationships between function and the onset of clinical symptoms.

PURPOSE

to objectively assess the posture and function of the spine during standing, flexion and lateral bending in obese subjects with and without cLBP and to investigate the role of obesity in cLBP.

STUDY DESIGN

Cross-sectional study

PATIENT SAMPLE

thirteen obese subjects, thirteen obese subjects with cLBP, and eleven healthy subjects were enrolled in this study.

OUTCOME MEASURES

we evaluated the outcome in terms of angles at the initial standing position (START) and at maximum forward flexion (MAX). The range of motion (ROM) between START and MAX was also computed.

METHODS

we studied forward flexion and lateral bending of the spine using an optoelectronic system and passive retroreflective markers applied on the trunk. A biomechanical model was developed in order to analyse kinematics and define angles of clinical interest.

RESULTS

obesity was characterized by a generally reduced ROM of the spine, due to a reduced mobility at both pelvic and thoracic level; a static postural adaptation with an increased anterior pelvic tilt. Obesity with cLBP is associated with an increased lumbar lordosis.In lateral bending, obesity with cLBP is associated with a reduced ROM of the lumbar and thoracic spine, whereas obesity on its own appears to affect only the thoracic curve.

CONCLUSIONS

obese individuals with cLBP showed higher degree of spinal impairment when compared to those without cLBP. The observed obesity-related thoracic stiffness may characterize this sub-group of patients, even if prospective studies should be carried out to verify this hypothesis.

Making fast-twitch dystrophic muscles bigger protects them from contraction injury and attenuates the dystrophic pathology

The lack of functional dystrophin protein in Duchenne muscular dystrophy (DMD) renders muscle fibers highly fragile and susceptible to damage during contractions. Contraction-mediated injury is a major contributor to the progressive degeneration and etiology of muscle wasting in DMD. The prevailing understanding is that large fibers are highly susceptible to contraction damage and are affected preferentially, whereas smaller fibers are relatively spared in DMD. We tested the hypothesis that a pharmacological treatment that caused myofiber hypertrophy would increase the susceptibility of muscles from dystrophin-deficient mdx mice to contraction-induced injury, and thus aggravate the dystrophic pathology. The beta-agonist formoterol (100 microg/kg per day, i.p.) was administered to mdx mice for 28 days. Formoterol increased muscle mass, fiber cross-sectional area, and maximum force producing capacity by 30%, 23%, and 21%, respectively, in fast-twitch tibialis anterior muscles of mdx mice. Myofiber hypertrophy and increased maximum force producing capacity were also observed in the predominantly slow-twitch soleus muscles of mdx mice. Our original hypothesis was rejected since tibialis anterior muscles from formoterol-treated mdx mice had lower cumulative force deficits, indicating that they were less susceptible to contraction-induced injury. Formoterol treatment did not affect injury susceptibility in soleus muscles. These findings indicate that making dystrophic muscles bigger protects them from contraction damage and does not aggravate the dystrophic pathophysiology. These novel results further support the contention that anabolic agents have therapeutic potential for muscle wasting conditions including DMD.