Long-Term Outcome of Interdisciplinary Management of Patients with Duchenne Muscular Dystrophy Receiving Daily Glucocorticoid Treatment

Incidence of Radiologically Confirmed Fractures in Adults With Duchenne Muscular Dystrophy

INTRODUCTION/AIMS

An increased risk of low trauma fractures is well documented in children and adolescents with duchenne muscular dystrophy (DMD). There is limited evidence regarding the fracture incidence of adults with DMD. The aim of this study was to examine radiologically confirmed fractures in adults with DMD and review bone health monitoring.

METHODS

This was a retrospective review of all adult males ≥ 16 years with DMD under the care of adult physicians in the West of Scotland (2013-2022). Information regarding fractures, bone health monitoring, and bisphosphonate therapy was collected.

RESULTS

Thirty-six men (median age at first visit 18.8 years) with DMD were included. Twelve were taking corticosteroids at first review, and a further 12 had previously been taking corticosteroids that were discontinued in childhood or adolescence. The fracture incidence rate was higher in the corticosteroid group (888.9 per 10,000 person years (95% CI 242.2-2275.9)) than in those not on corticosteroids (156.3 per 10,000 person years (95% CI 32.2-456.6)). Eighteen had lateral spine radiographs for vertebral fracture assessment and 15 had a DXA scan for bone density assessment during the follow-up period.

DISCUSSION

The fracture incidence in adult men with DMD is more than double that of UK men aged 18-49 years old, with an even higher incidence in those treated with corticosteroids. Fewer than half of the study population underwent bone monitoring. There is a need for enhanced clinical guidance for the monitoring and management of osteoporosis during transition and throughout adulthood.

Growth hormone and testosterone delay vertebral fractures in boys with muscular dystrophy on chronic glucocorticoids

Glucocorticoid use in Duchenne and Becker muscular dystrophy prolongs ambulation but cause significant skeletal toxicity. Our analysis has immediate clinical implications, suggesting that growth hormone and testosterone have a stronger effect prior to first and subsequent vertebral fracture, respectively, relative to bisphosphonates alone in children with dystrophinopathies on chronic glucocorticoids.

PURPOSE

Glucocorticoids prolong ambulation in boys with Duchenne muscular dystrophy; however, they have significant endocrine side effects. We assessed the impact of growth hormone (GH), testosterone, and/or zoledronic acid (ZA) on vertebral fracture (VF) incidence in patients with dystrophinopathies on chronic glucocorticoids.

METHODS

We conducted a longitudinal retrospective review of 27 males with muscular dystrophy. Accelerated failure time (AFT) models were used to estimate the relative time to VF while on GH, testosterone, and/or ZA compared to ZA alone. Results are reported as failure time ratio, where >1 indicates prolonged time versus <1 indicates shorter time to next VF.

RESULTS

The prevalence of growth impairment was 96% (52% utilized GH), pubertal delay was 86% (72% utilized testosterone), and low trauma fractures were 87% (72% utilized ZA). Multivariable analysis of the AFT models showed that participants on either GH or testosterone treatment relative to ZA alone experienced prolonged time to next VF (1.253, P<0.001), with GH being the significant contributor when analyzed independently from testosterone (1.229, P<0.001). Use of ZA with GH or testosterone relative to ZA alone resulted in prolonged time to next VF (1.171, P<0.001), with testosterone being a significant contributor (1.130, P=0.033).

CONCLUSION

GH and testosterone each decreased VF risk in patients independent of or in combination with ZA, respectively.

Reporting of paediatric osteoporotic vertebral fractures in Duchenne muscular dystrophy and potential impact on clinical management: the need for standardised and structured reporting

BACKGROUND

In boys with Duchenne muscular dystrophy (DMD), initiation of bisphosphonate is recommended upon identification of moderate or severe vertebral fractures, even if asymptomatic. Clear radiological reporting is important for consistency of clinical interpretation and management.

OBJECTIVES

To audit radiology reports of spine imaging for vertebral fracture assessment in DMD, and assess potential impact on diagnosis and management.

MATERIALS AND METHODS

Lateral thoracolumbar spine imaging (71 lateral spine radiographs and 13 lateral dual energy absorptiometry spine image) in 84 boys with DMD performed across two centres. Anonymised radiology reports by paediatric radiologists were circulated to two neuromuscular clinicians and two endocrinologists. Clinicians determined if there was vertebral fracture, no vertebral fracture, or unclear interpretation. Endocrinologists also determined if bisphosphonate was indicated. A single observer (a clinician with expertise in vertebral fracture assessment) performed vertebral fracture assessment in 37 images and re-reported using a structured format. Structured reports were re-circulated to the four clinicians to re-evaluate the degree of concordance in clinical diagnosis of vertebral fracture and treatment decisions with bisphosphonate.

RESULTS

The term "fracture" was used in 25/84 (30%) radiology reports and only in 8/43 (19%) with description of vertebral body abnormalities. Fracture grading was included in 7/43 (16%) radiology reports. Diagnostic concordance by the clinicians was noted in 36/84 (43%). Unclear interpretation was noted in 22% to 51% based on radiology reports. No unclear interpretation was noted with structured reports. Complete diagnostic (37/37, 100%) and treatment (37/37, 100%) concordance was noted with the structured reports, whereas complete diagnostic and treatment concordance was noted in only 16/37 (43%) and 17/37 (46%) of the radiology reports, respectively.

CONCLUSION

Only a third of radiology reports of spine imaging in DMD explicitly used the terminology "fracture". Grading was only noted in a small percentage. Variability in diagnostic interpretation by clinicians may lead to differing management plans. As identification of vertebral fracture is a trigger for treatment, developing reporting guidelines for paediatric vertebral fracture assessment will improve care. A structured template should be introduced for radiological reporting of paediatric vertebral fracture assessment.

Appendicular lean mass index changes in patients with Duchenne muscular dystrophy and Becker muscular dystrophy

INTRODUCTION

Mutations in the 79 exons of the dystrophin gene result in muscle wasting and weakness of varying clinical severity, ranging from severe/typical Duchenne muscular dystrophy (DMD) to intermediate DMD and mild Becker muscular dystrophy (BMD), depending on the frameshift of the mutation. We previously reported that males with DMD have progressively declining appendicular lean mass (ALM) and ALM index (ALMI) with age and worsening functional motor ability compared with healthy controls. These indices have not been studied in patients with intermediate DMD and BMD phenotypes and across DMD genotypes. In this study, we compared age-related trajectories of ALM and ALMI of patients who had (1) BMD without functional mobility deficits with patients who had DMD at different stages of disease and healthy controls; (2) a DMD intermediate phenotype with patients who had a typical DMD phenotype; and (3) DMD categorized by genotype.

METHODS

We conducted a retrospective review of ALM and ALMI data from 499 patients (ages 5-23 years) with DMD (466 typical and 33 intermediate) and 46 patients (ages 5-21 years) with BMD (without functional mobility deficits and functional mobility score of 1). Patients were grouped according to age reflecting disease stage (ages 5 to <7, 7 to <10, 10 to <14, and 14 to <20 years) and genotype (mutations in exons 1-30, 31-44, 45-62, and 63-79).

RESULTS

ALM and ALMI trajectories of patients with BMD paralleled those of healthy controls until adolescence, in contrast to patients with DMD. ALMI Z-scores of patients with BMD remained within ±2 SD without decline while those of patients with DMD fell below -2 SD around age 12 years. Patients with BMD had increasing ALM and ALMI with age, with peak accrual between ages 10 to <14 years. ALMI declined after age 14 years for those with intermediate DMD compared with 10 years for patients with typical DMD. Patients with mutations in exons 63-79 had a greater decline in ALMI as compared with those with other genotypes after age 10 years.

CONCLUSIONS

Age-related changes in ALMI in patients with BMD and intermediate DMD differ from those with typical DMD, reflecting their clinical phenotypes. ALM and ALMI should be further studied in patients with BMD and DMD subtypes for their potential value as surrogate markers to characterize the severity of BMD and DMD and inform clinical care decisions and clinical trial designs.

A novel splicing mutation identified in a DMD patient: a case report

Background

Duchenne muscular dystrophy (DMD, ORPHA:98896) is a lethal X-linked recessive disease that manifests as progressive muscular weakness and wasting. Mutations in the dystrophy gene (DMD) are the main cause of Duchenne muscular dystrophy.

Case presentation

This study aims to determine novel mutations of DMD and help preimplantation genetic diagnosis (PGD) for family planning. Here present a 4-year-old Chinses boy with DMD, whole-exome sequencing (WES) was performed to identify the molecular basis of the disease. It was confirmed that the boy carried a novel hemizygous mutation of NC_000023.11(NM_004006.3): c.5912_5922 + 19delinsATGTATG in DMD which inherited from his mother. This led to the aberrant splicing of DMD which demonstrated by a minigene splicing assay and further resulted in the impairment of the dystrophy protein.

Conclusions

Our study discovered a novel splicing mutation of DMD in a DMD patient, which expands the variant spectrum of this gene and provide precise genetic diagnosis of DMD for timely therapy. Meanwhile, this finding will supply valuable information for preimplantation genetic diagnosis.

Polysymptomatology and Polypharmacy at End of Life in Patients with Duchenne Muscular Dystrophy

OBJECTIVE

To characterize symptom frequency and symptom-directed treatment approaches in patients who died with advanced Duchenne muscular dystrophy (DMD).

STUDY DESIGN

This was a retrospective cohort study of patients in a multidisciplinary DMD program who died between January 1, 2013, and June 30, 2021. Inclusion criteria were patients who died with advanced DMD in the time period studied; exclusion criteria were low exposure to palliative care (<2 encounters). Demographic, symptom, and end-of-life data, as well as medications used for symptom management, were abstracted from the electronic medical record.

RESULTS

In total, 15 patients were eligible for analysis. The median age of death was 23 years (range 15-30 years). One (6.7%) experienced a full code at death, 8 (53.3%) had do-not-resuscitate orders, and 4 (26.7%) had limited do-not-resuscitate orders. Mean palliative care exposure was 1280 days. All 15 (100%) had pain and dyspnea; 14 (93.3%) anorexia, constipation, and sleep difficulty; 13 (86.7%) wounds; and 12 (80%) anxiety and nausea/vomiting. Multiple medications and drug classes were used to target symptoms.

CONCLUSIONS

We found significant polysymptomatology and polypharmacy in patients who died with advanced DMD. Clinicians who care for patients with advanced DMD should clarify goals of care and document advance care planning. Given the complexity of multisystem disease progression, palliative care should provide subspecialty pain management and assist with psychosocial burdens.

IL-33 Contributes to the Pathological Changes of Hair Follicles in Psoriasis: A Potential Target for Psoriatic Alopecia

Purpose

IL-33 is constitutively expressed in skin tissues. Alopecia, a T cells-driven disorder of the hair follicles (HFs), is a common complication in the development of psoriasis. However, the role of IL-33 in psoriatic alopecia remains uncovered. Here, we investigated the roles of IL-33 in inducing pathological changes of hair follicles in psoriasis.

Patients and Methods

Clinical samples and imiquimod (IMQ)-induced psoriatic mice samples were used to investigate the pathological changes and T-cell infiltration of HFs. By using immunohistochemistry staining, the distribution and expression alteration of IL-33 in HFs were determined. Next, by using IL-33 and ST2 knockout mice, we investigated the role of IL-33/ST2 axis in the pathological changes of HFs in psoriasis. Meanwhile, recombinant IL-33 protein was subcutaneous injected to confirm its effect. Finally, RNA sequencing was used to clarify the genes and signaling pathways that involved in this process. Differentially expressed genes were further verified by RT-PCR in cultured HFs in vitro.

Results

We found that the pathological changes of HFs and T cells infiltration in imiquimod-induced psoriatic mice were similar to that in psoriasis patients. The IL-33 positive keratinocytes in the outer root sheath of HFs were increased in both psoriasis patients and psoriatic model mice compared with the controls. By using gene knockout mice, we found that the pathological changes and T cell infiltration were attenuated in IL-33^-/- and ST2^-/- psoriatic model mice. In addition, subcutaneous injection of recombinant IL-33 exacerbated the pathological changes of HFs and T cell infiltration. RNA sequencing and RT-RCR revealed that IL-33 upregulated the transcription of genes related to keratinocytes proliferation and T lymphocytes chemotaxis.

Conclusion

Our study identifies that IL-33 promotes the pathological changes of HFs in psoriasis, which contributes to psoriatic alopecia. Inhibition of IL-33 may be a potential therapeutic approach for psoriatic alopecia.

No difference in postoperative complication rates or cardiopulmonary function for early versus late scoliosis correction in Duchenne muscular dystrophy

BACKGROUND

Given reduced rates of both pulmonary function decline and scoliosis progression with steroid treatment in Duchenne muscular dystrophy (DMD), the role of early scoliosis surgery has been questioned. The purpose of this study was to compare the postoperative complication rates of early versus late scoliosis correction in DMD.

METHODS

This study was a retrospective cohort, conducted at an academic tertiary level children's hospital. Patients with DMD who underwent posterior scoliosis correction, with preoperative pulmonary function testing [forced vital capacity (FVC)] were included and divided into two groups by preoperative curve angles: ≤ 45° and > 45°. The primary outcome variable was postoperative complications by Clavien-Dindo classification grading. Secondary outcome variables included postoperative complications occurring after the first 90 days, age at surgery, duration of wheelchair dependency preoperatively, pulmonary function, steroid utilization, shortening fraction by echocardiogram, surgery duration, intensive care unit/hospital length of stay, days intubated, infection, and percent curve correction. Two-tailed t-test and Chi-square testing were used for analysis of patient factors and Clavien-Dindo complication grade, respectively.

RESULTS

Thirty-one patients were included with a total follow-up of 8.3 ± 3.2 years, 4.8 ± 2.2 years post-spinal fusion. Steroid treatment (prednisone, deflazacort) was utilized for 21 (67.7%) patients. Primary curve correction was not different between groups (65.0% vs 71.4% [p = 0.37]). There were no significant differences in Clavien-Dindo classification grades between groups (p > 0.05). For the entire cohort, the overall complication rate was higher for patients with steroid treatment (61.9% vs 10.0% [p = 0.008]). Neither forced vital capacity nor fractional shortening on echocardiogram was different between groups at final follow-up (p = 0.6 and p = 0.4, respectively).

CONCLUSION

The comparable risk of perioperative complications for early and late scoliosis correction supports a "watchful waiting" approach, whereby curves less than 45° can be carefully followed while cardiopulmonary function is maintained. Patients undergoing steroid treatment should be counseled regarding the higher risk of postoperative blood transfusion and deep wound infection.

LEVEL OF EVIDENCE

III Retrospective cohort.

Development and economic evaluation of a patient-centered care model for children with Duchenne’s Muscular Dystrophy: A quasi-experimental study protocol (Preprint)

BACKGROUND

Duchenne muscular dystrophy (DMD) is a rare progressive muscular disease that primarily affects boys. A lack of comprehensive care for patients living with DMD is directly associated with a compromised quality of life (QoL) for those affected and their caregivers. This disease also has a huge economic impact on families as its treatment requires substantial direct, indirect, and informal care costs.

OBJECTIVE

This study presents a protocol developed to evaluate the feasibility and efficacy of a patient-centered care (PCC) model for children with DMD. The care model was designed with the aim to empower families, improve QoL, and reduce economic burden on their families.

METHODS

This study is planned as a quasi-experimental study that will enroll 70 consecutive families with boys (aged 5-15 years) with DMD visiting a tertiary care center. The study is being conducted in 2 phases (preintervention and postintervention phases, referred to as phase 1 and phase 2, respectively). During phase 1, the patients received routine care. The study is now in phase 2, with the intervention currently being administered. The intervention is based on the PCC model individualized by the intervention team. The model has a comprehensive DMD telecare component that includes teleconsultation as one of its key components to reduce in-person physician visits at the health facility. Teleconsultation is especially beneficial for late-ambulatory and nonambulatory patients. Data on economic burden are being collected for out-of-pocket expenses for both phases during in-person visits via telephone or messaging apps on a monthly basis. QoL data for patients and their primary caregivers are being collected at 3 time points (ie, time of enrollment, end of phase 1, and end of phase 2). Outcome measures are being assessed as changes in economic burden on families and changes in QoL scores.

RESULTS

Participant recruitment began in July 2021. The study is ongoing and expected to be completed by March 2023. The findings based on baseline data are expected to be submitted for publication in 2023.

CONCLUSIONS

This paper outlines a research proposal developed to study the impact of a PCC model for patients with DMD in low- and middle-income countries (LMICs). This study is expected to provide evidence of whether a multicomponent, patient-centric intervention could reduce economic burdens on families and improve their QoL. The results of this study could guide policy makers and health professionals in India and other LMICs to facilitate a comprehensive care program for patients living with DMD. The economic impact of a rare disease is an important consideration to formulate or evaluate any health policy or intervention related to new treatments and financial support schemes.

TRIAL REGISTRATION

Clinical Trials Registry India (ICMR-NIMS) CTRI/2021/06/034274; https://www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=56650.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/42491.

Bone health in Duchenne muscular dystrophy: clinical and biochemical correlates

PURPOSE

An increased fracture risk is commonly reported in Duchenne muscular dystrophy (DMD). Our aim was to investigate bone mineral density (BMD) and bone turnover, including sclerostin, and their association with markers of cardiac and respiratory performance in a cohort of DMD subjects.

METHODS

In this single center, cross sectional observational study, lumbar spine (LS) BMD Z-scores, C-terminal telopeptide of procollagen type I (CTX) and osteocalcin (BGP), as bone resorption and formation markers, respectively, and sclerostin were assessed. Left ventricular ejection fraction (LVEF) and forced vital capacity (FVC) were evaluated. Clinical prevalent fractures were also recorded.

RESULTS

Thirty-one patients [median age = 14 (12-21.5) years] were studied. Ambulant subjects had higher LS BMD Z-scores compared with non-ambulant ones and subjects with prevalent clinical fractures [n = 9 (29%)] showed lower LS BMD Z-scores compared with subjects without fractures. LS BMD Z-scores were positively correlated with FVC (r = 0.50; p = 0.01), but not with glucocorticoid use, and FVC was positively associated with BGP (r = 0.55; p = 0.02). In non-ambulant subjects, LS BMD Z-scores were associated with BMI (r = 0.54; p = 0.02) and sclerostin was associated with age (r = 0.44; p = 0.05). Age, BMI, FVC and sclerostin were independently associated with LS BMD Z-score in a stepwise multiple regression analysis. Older age, lower BMI, FVC and sclerostin were associated with lower LS BMD Z-scores.

CONCLUSION

In a cohort of DMD patients, our data confirm low LS BMD Z-scores, mainly in non-ambulant subjects and irrespective of the glucocorticoid use, and suggest that FVC and sclerostin are independently associated with LS BMD Z-scores.

Perspectives on Everyday Life Challenges of Danish Young People With Duchenne Muscular Dystrophy (DMD) on Corticosteroids

This study aimed to investigate perspectives on everyday life challenges of young persons with Duchenne muscular dystrophy in Denmark treated with corticosteroids perceived by young persons and their parents to improve rehabilitation interventions. Nineteen semi-structured interviews were conducted: 10 individual interviews with 10 persons with DMD and six individual interviews with parents (five mothers and one father) and three couple interviews (three mothers and three fathers). The analysis was guided by interpretive description methodology and Antonovsky’s Sense of Coherence theory. The results indicated that persons with Duchenne muscular dystrophy existed in a flux between experiencing greater Sense of Coherence revolving around normality and less Sense of Coherence exposing their vulnerability which unfolded in four opposing themes: (1) bodily ability and disability, (2) content and anxious, (3) sociable and lonely, and (4) independent and dependent. Future rehabilitation should aim at supporting resistance resources promoting bodily ability, being content, sociable, and independent.

Identifying the hub genes for Duchenne muscular dystrophy and Becker muscular dystrophy by weighted correlation network analysis

Background

The goal of this study is to identify the hub genes for Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) via weighted correlation network analysis (WGCNA).

Methods

The gene expression profile of vastus lateralis biopsy samples obtained in 17 patients with DMD, 11 patients with BMD and 6 healthy individuals was downloaded from the Gene Expression Omnibus (GEO) database (GSE109178). After obtaining different expressed genes (DEGs) via GEO2R, WGCNA was conducted using R package, modules and genes that highly associated with DMD, BMD, and their age or pathology were screened. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis and protein–protein interaction (PPI) network analysis were also conducted. Hub genes and highly correlated clustered genes were identified using Search Tool for the Retrieval of Interacting Genes (STRING) and Cystoscape software.

Results

One thousand four hundred seventy DEGs were identified between DMD and control, with 1281 upregulated and 189 downregulated DEGs. Four hundred and twenty DEGs were found between BMD and control, with 157 upregulated and 263 upregulated DEGs. Fourteen modules with different colors were identified for DMD vs control, and 7 modules with different colors were identified for BMD vs control. Ten hub genes were summarized for DMD and BMD respectively, 5 hub genes were summarized for BMD age, 5 and 3 highly correlated clustered genes were summarized for DMD age and BMD pathology, respectively. In addition, 20 GO enrichments were found to be involved in DMD, 3 GO enrichments were found to be involved in BMD, 3 GO enrichments were found to be involved in BMD age.

Conclusion

In DMD, several hub genes were identified: C3AR1, TLR7, IRF8, FYB and CD33(immune and inflammation associated genes), TYROBP, PLEK, AIF1(actin reorganization associated genes), LAPTM5 and NT5E(cell death and arterial calcification associated genes, respectively). In BMD, a number of hub genes were identified: LOX, ELN, PLEK, IKZF1, CTSK, THBS2, ADAMTS2, COL5A1(extracellular matrix associated genes), BCL2L1 and CDK2(cell cycle associated genes).

Knee Strength and Ankle Range of Motion Impacts on Timed Function Tests in Duchenne Muscular Dystrophy: In the Era of Glucocorticoids

BACKGROUND

Duchenne Muscular Dystrophy (DMD) is a neuromuscular disorder that presents in childhood and is characterized by slowly progressive proximal weakness and lower extremity contractures that limit ambulatory ability [1, 2]. Contractures develop in the ankles, knees, and hips due to muscle imbalances, fibrotic changes, loss of strength, and static positioning [2, 5]. Currently, standards of care guidelines emphasize the importance of maintaining good musculoskeletal alignment through stretching, bracing, and glucocorticoid (GC) therapy to preserve strength and function.

METHODS

This is a retrospective analysis of prospectively collected data through the CINRG Duchenne Natural history study (DNHS). The objectives of this analysis are to understand the progression of ankle contractures for individuals with DMD and to investigate the relationship between progressive lower limb contractures, knee strength, and Timed Function Tests.A collection of TFTs including supine to stand (STS), 10 meter walk test (10MWT), and timed stair climbing (4SC) have been used to monitor disease progression and are predictive of loss of ambulation in these patients [4]. Multiple factors contribute to loss of ambulation, including progressive loss of strength and contracture development that leads to changing biomechanical demands for ambulation. A better understanding of the changes in strength and range of motion (ROM) that contribute to loss of function is important in a more individualized rehabilitation management plan. In this longitudinal study, we measured strength using quantitative muscle testing (QMT) with the CINRG Quantitative Measurement System (CQMS)), ROM was measuresed with a goniometer and TFTs were measured using a standard stopwatch and methodology.

RESULTS

We enrolled 440 participants; mean baseline age was 8.9 (2.1, 28.0) years with 1321 observations used for analysis. GC use was stratified based on duration on drug with 18.7%at <  6 months or naïve; 4.3%<1 year; 58.0%1 <  10 years; and 19.3%between 10-25 years of GC use. Ankle ROM was better for those on GC compared to GC naive but did not significantly influence long-term progression rates. QMT, ROM, age and GCs contribute to speed of TFTs. Knee extension (KE) strength and Dorsiflexion (DF) ROM are significant predictors of speed for all TFTs (p <  0.001). Of the variables used in this analysis, KE strength is the primary predictor of walking speed, estimating that every pound increase in KE results in a 0.042 m/s improvement in 10MWT, and a smaller similar increase of 0.009 m/s with every degree of ankle DF ROM.

CONCLUSION

GC use provides an improvement in strength and ROM but does not affect rate of change. Knee strength has a greater influence on speed of TFTs than DF ROM, although both are statistically significant predictors of speed. Results show that retaining knee strength [1, 2], along with joint flexibility, may be important factors in the ability to perform walking, climbing and supine to stand activities.

The hair follicle-psoriasis axis: Shared regulatory mechanisms and therapeutic targets

It has long been known that there is a special affinity of psoriasis for the scalp: Here, it occurs most frequently, lesions terminate sharply in frontal skin beyond the hair line and are difficult to treat. Yet, surprisingly, scalp psoriasis only rarely causes alopecia, even though the pilosebaceous unit clearly is affected. Here, we systematically explore the peculiar, insufficiently investigated connection between psoriasis and growing (anagen) terminal scalp hair follicles (HFs), with emphasis on shared regulatory mechanism and therapeutic targets. Interestingly, several drugs and stressors that can trigger/aggravate psoriasis can inhibit hair growth (e.g. beta-blockers, chloroquine, carbamazepine, interferon-alpha, perceived stress). Instead, several anti-psoriatic agents can stimulate hair growth (e.g. cyclosporine, glucocorticoids, dithranol, UV irradiation), while skin/HF trauma (Köbner phenomenon/depilation) favours the development of psoriatic lesions and induces anagen in "quiescent" (telogen) HFs. On this basis, we propose two interconnected working models: (a) the existence of a bidirectional "hair follicle-psoriasis axis," along which keratinocytes of anagen scalp HFs secrete signals that favour the development and maintenance of psoriatic scalp lesions and respond to signals from these lesions, and (b) that anagen induction and psoriatic lesions share molecular "switch-on" mechanisms, which invite pharmacological targeting, once identified. Therefore, we advocate a novel, cross-fertilizing and integrative approach to psoriasis and hair research that systematically characterizes the "HF-psoriasis axis," focused on identification and therapeutic targeting of selected, shared signalling pathways in the future management of both, psoriasis and hair growth disorders.

The effect of oral bisphosphonate therapy on vertebral morphometry and fractures in patients with Duchenne muscular dystrophy and glucocorticoid-induced osteoporosis

INTRODUCTION/AIMS

Glucocorticoid-induced osteoporosis with vertebral fractures is frequent in patients with Duchenne muscular dystrophy (DMD). In this study, we evaluated the effects of oral bisphosphonate (BP) therapy on the prevalence and severity of vertebral fractures by vertebral morphometry assessment.

METHODS

We reviewed the records and radiographs of patients with DMD who had been treated with oral BP (weekly alendronate) and had undergone routine spine radiographic monitoring for glucocorticoid-induced osteoporosis at Cincinnati Children's Hospital Medical Center between 2010 and 2017. Study outcomes were thoracic and lumbar vertebral fracture prevalence and severity, assessed by Genant semiquantitative grading of vertebral morphometry, for up to 5 years of treatment.

RESULTS

Fifty-two patients (median age, 11.8 years; 88% prepubertal; 31% nonambulatory) had been treated with long-term glucocorticoids (median duration, 4.7 years at BP start). Most patients (75%) had mild vertebral height loss or fractures (Genant grade = 0 or 1) at baseline. The prevalence of vertebral fractures at each year of treatment was not statistically different from that at baseline (P = .08-1.00). Serial radiographs showed no longitudinal change in severity by Genant grade in most vertebrae (64%-80%). Improvement in vertebral fracture grade was observed in some patients.

DISCUSSION

We observed stable prevalence of vertebral fractures and no change in severity by Genant grade in most vertebrae for up to 5 years of treatment. Oral BP may mitigate development or progression of vertebral fractures and be beneficial for secondary prevention of glucocorticoid-induced osteoporosis in this population.

Decision-Making And Selection Bias in Four Observational Studies on Duchenne and Becker Muscular Dystrophy

BACKGROUND

Natural history data are essential for trial design in Duchenne (DMD) and Becker muscular dystrophy (BMD), but recruitment for observational studies can be challenging.

OBJECTIVE

We reviewed reasons why patients or caregivers declined participation, and compared characteristics of participants and non-participants to assess possible selection bias in four observational studies, three on DMD and one on BMD.

METHODS

Three pediatric DMD studies focused on cross-sectional cognitive function and brain MRI (DMDbrain, n = 35 and DMDperfusion, n = 12), and on longitudinal upper extremity function and muscle MRI (DMDarm, n = 22). One adult BMD study assessed longitudinal functioning (n = 36). Considerations for non-participation were retrospectively reviewed from screening logs. Age, travel-time, DMD gene mutations and age at loss of ambulation (DMDarm and BMD study only), of participants and non-participants were derived from the Dutch Dystrophinopathy Database and compared using nonparametric tests (p < 0.05).

RESULTS

The perceived burden of the protocol (38.2%), use of MRI (30.4%), and travel-time to the study site (19.1%) were the most frequently reported considerations for non-participation. Only few patients reported lack of personal gain (0.0- 5.9%). Overall, participating patients were representative for the studied sub-populations, except for a younger age of DMDarm study participants and a complete lack of participants with a mutation beyond exon 63.

CONCLUSION

Optimizing patient involvement in protocol design, improving MRI experiences, and integrating research into clinics are important factors to decrease burden and facilitate participation. Nationwide registries are essential to compare participants and non-participants and ensure representative observational research. Specific effort is needed to include patients with distal mutations in cognitive studies.

The pan HDAC inhibitor Givinostat improves muscle function and histological parameters in two Duchenne muscular dystrophy murine models expressing different haplotypes of the LTBP4 gene

BACKGROUND

In the search of genetic determinants of Duchenne muscular dystrophy (DMD) severity, LTBP4, a member of the latent TGF-β binding protein family, emerged as an important predictor of functional outcome trajectories in mice and humans. Nonsynonymous single-nucleotide polymorphisms in LTBP4 gene associate with prolonged ambulation in DMD patients, whereas an in-frame insertion polymorphism in the mouse LTBP4 locus modulates disease severity in mice by altering proteolytic stability of the Ltbp4 protein and release of transforming growth factor-β (TGF-β). Givinostat, a pan-histone deacetylase inhibitor currently in phase III clinical trials for DMD treatment, significantly reduces fibrosis in muscle tissue and promotes the increase of the cross-sectional area (CSA) of muscles in mdx mice. In this study, we investigated the activity of Givinostat in mdx and in D2.B10 mice, two mouse models expressing different Ltbp4 variants and developing mild or more severe disease as a function of Ltbp4 polymorphism.

METHODS

Givinostat and steroids were administrated for 15 weeks in both DMD murine models and their efficacy was evaluated by grip strength and run to exhaustion functional tests. Histological examinations of skeletal muscles were also performed to assess the percentage of fibrotic area and CSA increase.

RESULTS

Givinostat treatment increased maximal normalized strength to levels that were comparable to those of healthy mice in both DMD models. The effect of Givinostat in both grip strength and exhaustion tests was dose-dependent in both strains, and in D2.B10 mice, Givinostat outperformed steroids at its highest dose. The in vivo treatment with Givinostat was effective in improving muscle morphology in both mdx and D2.B10 mice by reducing fibrosis.

CONCLUSION

Our study provides evidence that Givinostat has a significant effect in ameliorating both muscle function and histological parameters in mdx and D2.B10 murine models suggesting a potential benefit also for patients with a poor prognosis LTBP4 genotype.

The clinical course of Duchenne muscular dystrophy in the corticosteroid treatment era: a systematic literature review

Background

Duchenne muscular dystrophy (DMD) is a severe rare progressive inherited neuromuscular disorder, leading to loss of ambulation (LOA) and premature mortality. The standard of care for patients with DMD has been treatment with corticosteroids for the past decade; however a synthesis of contemporary data describing the clinical course of DMD is lacking. The objective was to summarize age at key clinical milestones (loss of ambulation, scoliosis, ventilation, cardiomyopathy, and mortality) in the corticosteroid-treatment-era.

Methods

A systematic review was conducted using MEDLINE and EMBASE. The percentage experiencing key clinical milestones, and the mean or median age at those milestones, was synthesized from studies from North American populations, published between 2007 and 2018.

Results

From 5637 abstracts, 29 studies were included. Estimates of the percentage experiencing key clinical milestones, and age at those milestones, showed heterogeneity. Up to 30% of patients lost ambulation by age 10 years, and up to 90% by 15 years of age. The mean age at scoliosis onset was approximately 14 years. Ventilatory support began from 15 to 18 years, and up to half of patients required ventilation by 20 years of age. Registry-based estimates suggest that 70% had evidence of cardiomyopathy by 15 years and almost all by 20 years of age. Finally, mortality rates up to 16% by age 20 years were reported; among those surviving to adulthood mortality was up to 60% by age 30 years.

Conclusions

Contemporary natural history studies from North America report that LOA on average occurs in the early teens, need for ventilation and cardiomyopathy in the late teens, and death in the third or fourth decade of life. Variability in rates may be due to differences in study design, treatment with corticosteroids or other disease-modifying agents, variations in clinical practices, and dystrophin mutations. Despite challenges in synthesizing estimates, these findings help characterize disease progression among contemporary North American DMD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01862-w.

Recent advances of glucocorticoids in the treatment of Duchenne muscular dystrophy (Review)

Duchenne muscular dystrophy (DMD) is the most common degenerative neuromuscular disease. The incidence of DMD in live births is 1/3,600-1/6,000. Although glucocorticoid-dependent medication is the mainstay treatment option for DMD, a standard treatment regimen has yet to be determined. The present review discusses the literature on the timing, methods and courses of glucocorticoid treatment for DMD. The review highlights the importance of the immediate commencement of glucocorticoid treatment following the diagnosis of DMD, with weekend-only administration being advantageous. Adherence to long-term single-glucocorticoid therapy can delay the loss of ambulation ability, and the side effects of the treatment are controllable. However, the standard medication for patients of different ages and stages of disease development, and the use of combination therapy require further investigation.

Growth and nutrition in pediatric neuromuscular disorders

BACKGROUND & AIMS

Little is currently known about the nutrition and growth outcomes in children with neuromuscular disorders (NMDs), and these are likely disease dependent. The aim of this study was to describe the range of nutritional issues in pediatric NMDs and identify similarities and differences in growth outcomes and nutritional needs in children with a variety of NMDs at different ages, with the goal of informing future services.

METHODS

In this cross-sectional study we collected data on growth, dietetic interventions and nutrition-related issues in 160 children who attended a multidisciplinary clinic in a tertiary children's hospital, from February to December 2019. Children with significant weakness affecting mobility before the age of 3 years were clinically grouped into 'early-onset NMDs'.

RESULTS

Across our clinic, 42.5% children had a history of chronic gastrointestinal issues, and 34.4% received dietetic care on the day of clinical visit. Children with early-onset NMDs had significantly higher prevalence of swallowing issues, gastroesophageal reflux, and vomiting, as well as higher frequency of dietetic consultations, high energy diet, swallowing assessment and tube-feeding, compared to later-onset NMDs (p < 0.05). In total, 49.2% children with NMDs had an abnormal weight, in which the prevalence of underweight (n = 24, 19.2%) was significantly higher compared to normal Australian children (8.2%) (p < 0.05). In Duchenne muscular dystrophy, over 50% children were overweight/obese.

CONCLUSION

Among children with NMDs, there were many disease-specific nutrition-related symptoms, growth issues, and dietetic practices that were tailored to individual needs. Future studies should focus on measuring the impact of specific dietetic practices on growth and nutritional outcomes, as well as developing a precision medicine approach tailored to the individual nutritional needs of children with NMDs.

A Multidisciplinary Evaluation of Patients with DMD in An Italian Tertiary Care Center

With more widespread prolonged survival, Duchenne muscular dystrophy patients progressively experience multisystem complications. We retrospectively reviewed the charts of 132 Duchenne patients (112 alive/20 dead, age 3.5÷32.3 years) with the aims: 1) to provide a comprehensive description of the clinical status considering different aspects of the disease; 2) to propose a new scoring tool able to consider and pool together heterogeneous different functional. Five functions were analyzed: cardiac, respiratory, nutritional, ambulation and scoliosis. For each function, different items were considered and classified according to clinical severity (as indicated by international guidelines) and an incremental scoring was assigned. In addition, a global score incorporating all functions was defined. The scoring system confirmed that despite the significant protective role of steroids, all functions deteriorated with age. The severity of the global score became significantly higher since the age of 13 years. The severity of cardiac, respiratory and nutritional dysfunction was higher since 18 years. Deceased patients were characterized by significantly worse cardiac function, absence of steroid therapy and later use of respiratory assistive devices. The index proposed in this pilot study is a promising tool able to aggregate and correlate heterogeneous functions. It could become either an individual prognostic indicator of decline or a global score to evaluate changes in clinical trials therefore allowing multicenter studies, optimizing the management of both the primary and the secondary complications of the disease and understanding their relative impact.

Age-related changes in appendicular lean mass in males with Duchenne muscular dystrophy: A retrospective review

BACKGROUND

Appendicular lean mass (ALM) trajectory in males with Duchenne muscular dystrophy (DMD) has potential applicability for treatment and research and has not been characterized.

METHODS

This chart review included longitudinal data on 499 males with DMD receiving glucocorticoids and 693 controls, ages 5 to 22.9 y. ALM (kg) was measured by dual energy x-ray absorptiometry (DXA). Appendicular lean mass index (ALMI, kg/m² ) was calculated for height adjustment. Reference centiles were generated using data from healthy controls, and ALM and ALMI Z-scores were calculated for patients with DMD. Generalized linear models were used to estimate median Z-scores by age and functional mobility status (FMS) score. ALM velocity by age was modeled using superimposition, translation and rotation (SITAR).

RESULTS

Compared to controls, males with DMD had lower ALM from an early age. ALMI Z-scores dropped below 0 at age 8 y or FMS of 2, and below -2.0 at age 13 y or FMS of 3 (P < .05). Age at peak ALM velocity was similar in both groups, but the magnitude was higher in controls (3.5 vs. 0.7 kg/y, P < .0001). Patients with DMD had a transient loss of ALM around age 12 y, an increase at age 14 y, then a further decline at age 16 y, remaining low thereafter.

CONCLUSIONS

Males with DMD have progressive decline in lean mass with age and worsening functional mobility. DXA measurement of ALM may be useful for monitoring lean mass status in patients with DMD, providing valuable information for individual treatment plans and research endeavors.

A survey of the feasibility of developing osteoporosis clinical trials in Duchenne muscular dystrophy: Survey of the opinion of young people with Duchenne muscular dystrophy, families and clinicians

BACKGROUND/AIMS

Given the extent of osteoporosis in people with Duchenne muscular dystrophy treated with glucocorticoids and the limited evidence of bone-protective therapies, clinical trials are needed. We conducted surveys to obtain the opinion of young people with Duchenne muscular dystrophy, parents/guardians and neuromuscular clinicians on the feasibility of osteoporosis clinical trials in this population.

METHODS

Online surveys were sent to three groups: (a) people with a confirmed diagnosis of Duchenne muscular dystrophy (≥14 years), (b) parents and guardians and (c) neuromuscular clinicians in the UK NorthStar Clinical Network. Surveys (a) and (b) were distributed via the UK Duchenne muscular dystrophy Registry.

RESULTS

Survey respondents included 52 people with Duchenne muscular dystrophy with a median age of 17 years (range: 14, 40) and 183 parents/guardians. Fourteen out of 23 (61%) NorthStar centres responded. Of the 52 people with Duchenne muscular dystrophy, 13 (25%) were very concerned about their bone health and 21 (40%) were slightly concerned. Of the 183 parents/guardians, 75 (41%) were very concerned about their son's bone health and 90 (49%) were slightly concerned. Fractures and quality of life were the top two main outcome measures identified by people with Duchenne muscular dystrophy. Fractures and bone density were the top two main outcome measures identified by parents/guardians and neuromuscular clinicians. Thirty percent of people with Duchenne muscular dystrophy and 40% of parents/guardians would not take part if an osteoporosis trial involved a placebo that was administered parenterally. Only 2 of the 14 NorthStar centres (14%) would enrol people with Duchenne muscular dystrophy if a parenteral placebo was used in an osteoporosis trial in Duchenne muscular dystrophy.

CONCLUSION

There is great awareness of bone health and the need for bone-protective trials among people with Duchenne muscular dystrophy and their carers. However, a proportion of people with Duchenne muscular dystrophy and parents are reluctant to participate in a placebo-controlled osteoporosis trial that included a parenteral therapy. A larger proportion of health care experts are unwilling to enrol their patients in such a trial. Our finding is relevant for the design of bone-protective studies in Duchenne muscular dystrophy.

Nutritional practices in pediatric patients with neuromuscular disorders

Children with neuromuscular disorders (NMDs) may experience a spectrum of nutritional issues with adverse health consequences. This review summarizes the current understanding of nutritional care in pediatric NMDs, recognizing disease-specific aspects of nutrition alongside the challenges and needs in dietetic care. General or disease-related nutritional issues for children with NMDs include being underweight, overweight, or obese and having swallowing difficulty, gastroesophageal reflux, diarrhea, and/or constipation. Specific challenges in NMD nutritional assessment include alterations in body composition and energy requirements and difficulties in measuring anthropometry. Multidisciplinary dietetic intervention focuses on optimizing nutrient intakes to avert growth failure or obesity and managing feeding difficulties and gastrointestinal problems. Care guidelines are disease specific and vary in approach and detail. To promote best clinical practice across diverse settings, a standardized approach to assessing growth and nutrition across all pediatric NMDs is needed to direct optimal care centered on individual requirements. Future studies should focus on determining the prevalence of specific nutritional issues and the effectiveness of specific interventions among various pediatric NMD populations.

Janus effect of glucocorticoids on differentiation of muscle fibro/adipogenic progenitors

Muscle resident fibro-adipogenic progenitors (FAPs), support muscle regeneration by releasing cytokines that stimulate the differentiation of myogenic stem cells. However, in non-physiological contexts (myopathies, atrophy, aging) FAPs cause fibrotic and fat infiltrations that impair muscle function. We set out to perform a fluorescence microscopy-based screening to identify compounds that perturb the differentiation trajectories of these multipotent stem cells. From a primary screen of 1,120 FDA/EMA approved drugs, we identified 34 compounds as potential inhibitors of adipogenic differentiation of FAPs isolated from the murine model (mdx) of Duchenne muscular dystrophy (DMD). The hit list from this screen was surprisingly enriched with compounds from the glucocorticoid (GCs) chemical class, drugs that are known to promote adipogenesis in vitro and in vivo. To shed light on these data, three GCs identified in our screening efforts were characterized by different approaches. We found that like dexamethasone, budesonide inhibits adipogenesis induced by insulin in sub-confluent FAPs. However, both drugs have a pro-adipogenic impact when the adipogenic mix contains factors that increase the concentration of cAMP. Gene expression analysis demonstrated that treatment with glucocorticoids induces the transcription of Gilz/Tsc22d3, an inhibitor of the adipogenic master regulator PPARγ, only in anti-adipogenic conditions. Additionally, alongside their anti-adipogenic effect, GCs are shown to promote terminal differentiation of satellite cells. Both the anti-adipogenic and pro-myogenic effects are mediated by the glucocorticoid receptor and are not observed in the presence of receptor inhibitors. Steroid administration currently represents the standard treatment for DMD patients, the rationale being based on their anti-inflammatory effects. The findings presented here offer new insights on additional glucocorticoid effects on muscle stem cells that may affect muscle homeostasis and physiology.

Synergistic effect of glucocorticoids and IGF-1 on myogenic differentiation through the Akt/GSK-3β pathway in C2C12 myoblasts

Purpose: Glucocorticoids are the only therapeutics that can delay the progression of Duchenne musculardystrophy (DMD), the most prevalent type of inherited neuromuscular disorder in males. However, beyond theiranti-inflammatory effects, glucocorticoids have other underlying mechanisms that remain unclear. Moreover, muscleand circulating levels of insulin growth factor-1 (IGF-1) often decrease in response to glucocorticoids. Therefore, wehypothesized that glucocorticoids, either alone or in combination with IGF-1, can improve myogenic differentiation.Materials and methods: Established C2C12 myoblasts were employed as an in vitro model of myogenic differentiation,and myogenic differentiation markers, as assessed by Western blot (myogenin, MyoD, and MyHC protein expression),cellular morphology analysis (fusion index) and RT-PCR (MCK mRNA expression), were measured.Results: Myogenic differentiation markers were increased by glucocorticoid treatment. Furthermore, this effect was furtherenhanced by IGF-1, and these results suggest that glucocorticoids, either alone or together with IGF-1, can promotemyogenic differentiation. Akt and GSK-3β play important roles in myogenic differentiation. Interestingly, the levels ofboth phosphorylated Ser473-Akt and phosphorylated Ser9-GSK-3β were increased by glucocorticoid and IGF-1 cotreatment.Pharmacological manipulation with LY294002 and LiCl was employed to inhibit Akt and GSK-3β, respectively.We found that cellular differentiability was inhibited by LY294002 and enhanced by LiCl, indicating that theAkt/GSK-3β signaling pathway is activated by glucocorticoid and IGF-1 treatment to promote myogenic differentiation.Conclusions: Glucocorticoids together with IGF-1 promote myogenic differentiation through the Akt/GSK-3βpathway. Thus, these results further our knowledge of myogenic differentiation and may offer a potential alternativestrategy for DMD treatment based on glucocorticoid and IGF-1.

Real-world outcomes of long-term prednisone and deflazacort use in patients with Duchenne muscular dystrophy: experience at a single, large care center

Aim: To assess outcomes among patients with Duchenne muscular dystrophy receiving deflazacort or prednisone in real-world practice. Methods: Clinical data for 435 boys with Duchenne muscular dystrophy from Cincinnati Children’s Hospital Medical Center were studied retrospectively using time-to-event and regression analyses. Results: Median ages at loss of ambulation were 15.6 and 13.5 years among deflazacort- and prednisone-initiated patients, respectively. Deflazacort was also associated with a lower risk of scoliosis and better ambulatory function, greater % lean body mass, shorter stature and lower weight, after adjusting for age and steroid duration. No differences were observed in whole body bone mineral density or left ventricular ejection fraction. Conclusion: This single center study adds to the real-world evidence associating deflazacort with improved clinical outcomes.

Phase 1 Study of Edasalonexent (CAT-1004), an Oral NF-κB Inhibitor, in Pediatric Patients with Duchenne Muscular Dystrophy

Background:

Edasalonexent is an orally administered small molecule designed to inhibit NF-κB, which is activated from infancy in Duchenne muscular dystrophy and is central to causing muscle damage and preventing muscle regeneration.

Objective:

Evaluate the safety, tolerability, pharmacokinetics and exploratory pharmacodynamics of three doses of edasalonexent in ambulatory males ≥4 to <8 years of age with genetically confirmed Duchenne muscular dystrophy.

Methods:

This was a 1-week, open-label, multiple-dose study with 3 sequential ascending doses (33, 67 and 100 mg/kg/day) of edasalonexent administered under different dietary conditions to 17 males with a mean age of 5.5 years.

Results:

All doses of edasalonexent were well tolerated, with no serious adverse events, no drug discontinuations and no dose reductions. The majority of adverse events were mild, and the most common adverse events were gastrointestinal (primarily diarrhea). Edasalonexent was rapidly absorbed with peak levels observed 2–6 hours after dosing and exposures appeared to increase nearly proportionally to dose for the 2 lower and all 3 doses under low-fat and high-fat meal conditions, respectively. Only minor plasma accumulation of edasalonexent was observed with 7 days of dosing. After treatment with edasalonexent for 7 days, levels of NF-κB-regulated genes and serum proteins were decreased.

Conclusions:

This first report of edasalonexent oral administration for one week in male pediatric patients with Duchenne muscular dystrophy showed that treatment was well tolerated and inhibited NF-kB pathways.

Increased Blood Pressure and Body Mass Index as Potential Modifiable Factors in The Progression of Myocardial Dysfunction in Duchenne Muscular Dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is characterized by progressive cardiomyopathy. Left ventricular (LV) function may worsen by factors increasing LV afterload such as hypertension and obesity.

OBJECTIVE

To identify potential modifiable risk factors for progression of cardiomyopathy in Duchenne muscular dystrophy (DMD).

METHODS

We retrospectively analysed systolic blood pressures (SBP) and body-mass indexes (BMI) from 273 visits of 65 DMD patients aged 4-18 years between 2003 and 2016, divided in 14 age groups. Values were normalized using Z-scores (Z-SBP and Z-BMI). A linear mixed model was used to analyse correlations between Z-SBP and BMI, steroid use, age, ambulatory status and cardiac medication (CM) use. To study the relationship between SBP and BMI and myocardial deformation prior to the onset of clinical cardiomyopathy, LV deformation, defined by global longitudinal strain (GLS), was quantified in a subset of 36 patients <11 years. Multiple linear regression was used to study the relation between GLS and clinical parameters.

RESULTS

Median follow-up was 5 years. SBP was significantly elevated in all age groups under 14 years (p≤0.04) and 15-16 years (p = 0.033) and correlated positively with BMI (p = 0.001) and negatively with CM use over time (p = 0.018). Z-BMI followed a bell-shaped distribution and plotted approximately one standard deviation above the mean in patients between 7 and 15 years. In the subset of younger patients, reduced GLS was associated with higher BMI (β= 0.348, p = 0.004).

CONCLUSIONS

SBP and BMI may be potentially modifiable factors to retard deterioration of LV function in DMD.

Pharmacotherapy of Duchenne Muscular Dystrophy

Drug development and pharmacotherapy of rare pediatric diseases have significantly expanded over the last decade, in part due to incentives and financial support provided by governments, regulators, and nonprofit foundations. Duchenne muscular dystrophy (DMD) is among the most common rare pediatric disorders, and clinical trials of therapeutic approaches have seen dramatic expansion. Pharmacotherapeutic standard of care has been limited to off-label prescription of high-dose, daily corticosteroids (prednisone, deflazacort). Deflazacort received FDA approval for DMD in 2016, although the price increases associated with formal FDA approval and the severe side effects associated with corticosteroid use have limited patient/physician uptake and insurance coverage in the USA. In Europe, EMA has given conditional marketing authorization for prescription of Translarna (a stop codon read-through drug prescribed to ~10% of DMD patients), although there is not yet evidence of clinical efficacy. The FDA awarded conditional approval to etiplirsen, an exon-skipping oligonucleotide drug, based on accelerated pathways (increased dystrophin production in patient muscle). Evidence of clinical efficacy remains the focus of post-marketing studies. There are many innovative pharmacotherapies under clinical development for DMD (Phase I, II, and III clinical trials). All are "disease modifying" in the sense that none seek to replace the full-length, normal DMD gene or dystrophin protein, but instead either seek to introduce an abnormal "Becker-like" version of the gene or protein or target pathophysiological pathways downstream of the primary defect. It is envisioned that the most significant benefit to DMD patients will be through multidrug approaches simultaneously aiming to introduce partially functional dystrophin in patient muscle while also targeting both chronic inflammation and the fibrofatty replacement of muscle.

The role of delayed bone age in the evaluation of stature and bone health in glucocorticoid treated patients with Duchenne muscular dystrophy

Background

Low bone mineral density and an increased risk of appendicular and vertebral fractures are well-established consequences of Duchenne muscular dystrophy (DMD) and the risk of fractures is exacerbated by long-term glucocorticoid treatment. Monitoring of endocrine and skeletal health and timely intervention in at-risk patients is important in the management of children with DMD.

Methods

As part of the Norwegian Duchenne muscular dystrophy cohort study, we examined the skeletal maturation of 62 boys less than 18 years old, both currently glucocorticoid treated (n = 44), previously treated (n = 6) and naïve (n = 12). The relationship between bone age, height and bone mineral density (BMD) Z-scores was explored.

Results

The participants in the glucocorticoid treated group were short in stature and puberty was delayed. Bone age was significantly delayed, and the delay increased with age and duration of treatment. The difference in height between glucocorticoid treated and naïve boys was no longer significant when height was corrected for delayed skeletal maturation. Mean BMD Z-scores fell below − 2 before 12 years of age in the glucocorticoid treated group, with scores significantly correlated with age, duration of treatment and pubertal development. When BMD Z-scores were corrected for by retarded bone age, the increase in BMD Z-scores was significant for all age groups.

Conclusion

Our results suggest that skeletal maturation should be assessed in the evaluation of short stature and bone health in GC treated boys with DMD, as failing to consider delayed bone age leads to underestimation of BMD Z-scores and potentially overestimation of fracture risk.

Efficacy of Denosumab for Glucocorticoid-Induced Osteoporosis in an Adolescent Patient with Duchenne Muscular Dystrophy: A Case Report

CASE

We report the case of a 13-year-old boy with Duchenne muscular dystrophy (DMD) who sustained bilateral femoral neck fractures associated with glucocorticoid-induced osteoporosis. Denosumab therapy for 18 months markedly improved the lumbar bone mineral density and the bone turnover markers. No fractures or complications were recorded during the treatment period.

CONCLUSION

To the best of our knowledge, this is the first description of denosumab treatment for glucocorticoid-induced osteoporosis in a patient with DMD. The drug merits additional testing as an effective therapy for osteoporosis in patients with DMD.

Comparison of Pulmonary Function Decline in Steroid-Treated and Steroid-Naïve Patients with Duchenne Muscular Dystrophy

OBJECTIVE

To describe and compare the lung function decline in patients with Duchenne muscular dystrophy on glucocorticoid therapy in contrast with glucocorticoid-naïve patients, and to define the deciles of pulmonary decline in glucocorticoid-treated patients.

STUDY DESIGN

This retrospective study examined lung function of patients with Duchenne muscular dystrophy over 6 years of age followed between 2001 and 2015 at 2 centers-glucocorticoid-treated patients in Cincinnati, Ohio, and glucocorticoid-naïve patients in Paris, France. Forced vital capacity (FVC, FVC%), forced expiratory volume in 1 second, maximal inspiratory pressure, maximal expiratory pressure, and peak expiratory flow data were analyzed. Only FVC data were available for the French cohort.

RESULTS

There were 170 glucocorticoid-treated patients (92%), 5 patients (2.7%) with past glucocorticoid use, and 50 French glucocorticoid-naïve patients. The peak absolute FVC was higher and was achieved at earlier ages in glucocorticoid-treated compared with glucocorticoid-naïve patients (peak FVC, 2.4 ± 0.6 L vs 1.9 ± 0.7 L; P < .0001; ages 13.5 ± 3.0 years vs 14.3 ± 2.8 years; P = .03). The peak FVC% was also higher and was achieved at earlier ages in glucocorticoid-treated patients (peak FVC%, 105.1 ± 25.1% vs 56 ± 20.9%; P < .0001; ages 11.9 ± 2.9 years vs 13.6 ± 3.2 years; P = .002). Rates of decline for both groups varied with age. Maximal rates of decline were 5.0 ± 0.26% per year (12-20 years) for glucocorticoid-treated and 5.1 ± 0.39% per year for glucocorticoid-naïve patients (11-20 years; P = .2). Deciles of FVC% decline in glucocorticoid-treated patients show that patients experience accelerated decline at variable ages.

CONCLUSIONS

These data describe nonlinear rates of decline of pulmonary function in patients with Duchenne muscular dystrophy, with improved function in glucocorticoid-treated patients. FVC% deciles may be a useful tool for clinical and research use.

Variability and trends in corticosteroid use by male United States participants with Duchenne muscular dystrophy in the Duchenne Registry

Background

Treatment options for Duchenne muscular dystrophy remain limited, although consensus treatment guidelines recommend corticosteroid use.

Methods

This retrospective analysis assessed corticosteroid use in ambulatory and nonambulatory US males with Duchenne, age 35 and under, or Becker muscular dystrophy, who enrolled in The Duchenne Registry from 2007 to 2016 (formerly DuchenneConnect).

Results

The mean (SD) age of corticosteroid use initiation was 5.9 (2.5) years, and deflazacort use (54%) was slightly more common than prednisone/prednisolone (46%). Among all responses from those with Duchenne, 63% were currently on corticosteroids, 12% were no longer on corticosteroids, and 25% had never been on corticosteroids. Among those who were nonambulatory, 49% were currently on corticosteroids, 28% had discontinued corticosteroids, and 23% had never used corticosteroids. Primary reasons for never initiating therapy were that corticosteroids were not prescribed or recommended and concerns about side effects. Corticosteroid use was maximal at age 8 (84% on corticosteroids) and gradually declined from age 10 to 19. The primary reasons for corticosteroid discontinuation were problems with side effects (65%) or not enough benefit (28%). Average doses of corticosteroids were below recommended doses. In the 159 responses with Becker muscular dystrophy, 20% were currently using corticosteroids.

Conclusions

Recognizing the self-selected nature of participation, it appears that a considerable proportion of US participants registered with The Duchenne Registry were either not on corticosteroids or not on recommended doses despite consensus recommendations. Side effects were a consideration in initiating and discontinuing treatment.

These data reinforce the need for additional treatment options for those affected by Duchenne.

Growth, pubertal development, and skeletal health in boys with Duchenne Muscular Dystrophy

PURPOSE OF REVIEW

Glucocorticoid therapy is currently the most widely used treatment for Duchenne muscular dystrophy (DMD), having consistently shown to prolong ambulation by 2 years, reduce the frequency of scoliosis, and improve cardiorespiratory function. Among the most frequent side effects of glucocorticoids are fractures due to osteoporosis, linear growth retardation or arrest, and pubertal delay, the subjects of this review.

RECENT FINDINGS

The diagnosis of osteoporosis has shifted in recent years away from a bone mineral density-centric to a fracture-focused approach, with particular emphasis on early vertebral fracture identification (one of the key triggers for osteoporosis intervention). Delayed puberty should be addressed in an age-appropriate manner, with numerous options available for sex steroid replacement. Growth impairment, however, is a more challenging complication of glucocorticoid-treated DMD, one that is most likely best addressed through growth-sparing therapies that target the dystrophinopathy.

SUMMARY

With glucocorticoid prescription an increasingly prevalent component of DMD care, early attention to management of osteoporosis and delayed puberty are important components of multidisciplinary and anticipatory care. The treatment of short stature remains controversial, with no accepted therapy currently available to over-ride the toxic effects of glucocorticoids on the growth axis.

Astragaloside IV ameliorates endoplasmic reticulum stress‑induced apoptosis of Aβ25‑35‑treated PC12 cells by inhibiting the p38 MAPK signaling pathway

Endoplasmic reticulum stress (ERS) serves a vital role in the pathological development of Alzheimer's disease (AD). ERS can promote programmed cell death (apoptosis) during AD; however, the specific molecular mechanisms that lead to ERS remain unclear. It is very important that a drug for the treatment of AD is identified. Our previous studies indicated that astragaloside IV (AST IV) has anti-inflammatory effects and helps cells resist oxidative stress. In the present study, western blotting and reverse transcription semi-quantitative polymerase chain reaction were used to detect protein and mRNA expression levels, flow cytometry was used to measure intracellular reactive oxygen species (ROS) levels, and superoxide dismutase (SOD) and malondialdehyde (MDA) activity was detected using commercially available kits. The results demonstrated that SOD activity was decreased, and MDA content, ROS levels, and the expression levels of p38 mitogen-activated protein kinase (MAPK) and ERS-associated proteins, including binding immunoglobulin protein/glucose-regulated protein and growth arrest- and DNA damage -inducible gene 153/C/EBP homologous protein, were increased in amyloid β (Aβ)_25-35-treated PC12 cells. Furthermore, to investigate the role of p38 MAPK and the effects of AST IV in an in vitro model of AD, SB203580, a p38 MAPK signaling pathway inhibitor, and AST IV were administered to Aβ_25-35-treated PC12 cells. The results revealed that AST IV protected the cells against AD. This effect may be caused by decreases in ROS levels, which may inhibit the p38 MAPK signaling pathway and thereby suppress ERS in Aβ_25-35-treated PC12 cells.

Fractures and bone health monitoring in boys with Duchenne muscular dystrophy managed within the Scottish Muscle Network

There are limited reports of radiologically confirmed fractures and bone health monitoring in with Duchenne muscular dystrophy. We performed a retrospective study of 91 boys, with a median age of 11.0 years, who are currently managed in Scotland with the aim to assess the frequency of radiologically confirmed fractures and report on bone health monitoring in relation to International Care Consensus Guidance. Of these boys, 59 (65%) were receiving glucocorticoid (GC) therapy and 23 (25%) had received previous treatment. Of those currently on GC, 37 (63%) had an assessment of bone mineral density and none had routine imaging for vertebral fractures during the study period. Of the 91 boys, 44 (48%) had sustained at least one symptomatic radiographically confirmed fracture. The probability of sustaining a first symptomatic fracture was 50% by 12.8 years old (95%CI: 12.1, 13.6). The most common sites for non-vertebral fracture were the femur and tibia. In this review of boys with DMD, almost half had sustained at least one radiologically confirmed symptomatic fracture. There is a need for standardized bone health monitoring in DMD that includes routine imaging of the spine to identify vertebral fractures, given the persistence of insult to the skeleton in these boys.

Mineralocorticoid Receptor Antagonists in Muscular Dystrophy Mice During Aging and Exercise

BACKGROUND

Mineralocorticoid receptor antagonists added to angiotensin converting enzyme inhibitors have shown preclinical efficacy for both skeletal and cardiac muscle outcomes in young sedentary dystrophin-deficient mdx mice also haploinsufficient for utrophin, a Duchenne muscular dystrophy (DMD) model. The mdx genotypic DMD model has mild pathology, making non-curative therapeutic effects difficult to distinguish at baseline. Since the cardiac benefit of mineralocorticoid receptor antagonists has been translated to DMD patients, it is important to optimize potential advantages for skeletal muscle by further defining efficacy parameters.

OBJECTIVE

We aimed to test whether therapeutic effects of mineralocorticoid receptor antagonists added to angiotensin converting enzyme inhibitors are detectable using three different reported methods of exacerbating the mdx phenotype.

METHODS

We tested treatment with lisinopril and the mineralocorticoid receptor antagonist spironolactone in: 10 week-old exercised, 1 year-old sedentary, and 5 month-old isoproterenol treated mdx mice and performed comprehensive functional and histological measurements.

RESULTS

None of the protocols to exacerbate mdx phenotypes resulted in dramatically enhanced pathology and no significant benefit was observed with treatment.

CONCLUSIONS

Since endogenous mineralocorticoid aldosterone production from immune cells in dystrophic muscle may explain antagonist efficacy, it is likely that these drugs work optimally during the narrow window of peak inflammation in mdx mice. Exercised and aged mdx mice do not display prolific damage and inflammation, likely explaining the absence of continued efficacy of these drugs. Since inflammation is more prevalent in DMD patients, the therapeutic window for mineralocorticoid receptor antagonists in patients may be longer.

Therapeutic potential of heat shock protein induction for muscular dystrophy and other muscle wasting conditions

Duchenne muscular dystrophy is the most common and severe of the muscular dystrophies, a group of inherited myopathies caused by different genetic mutations leading to aberrant expression or complete absence of cytoskeletal proteins. Dystrophic muscles are prone to injury, and regenerate poorly after damage. Remorseless cycles of muscle fibre breakdown and incomplete repair lead to progressive and severe muscle wasting, weakness and premature death. Many other conditions are similarly characterized by muscle wasting, including sarcopenia, cancer cachexia, sepsis, denervation, burns, and chronic obstructive pulmonary disease. Muscle trauma and loss of mass and physical capacity can significantly compromise quality of life for patients. Exercise and nutritional interventions are unlikely to halt or reverse the conditions, and strategies promoting muscle anabolism have limited clinical acceptance. Heat shock proteins (HSPs) are molecular chaperones that help proteins fold back to their original conformation and restore function. Since many muscle wasting conditions have pathophysiologies where inflammation, atrophy and weakness are indicated, increasing HSP expression in skeletal muscle may have therapeutic potential. This review will provide evidence supporting HSP induction for muscular dystrophy and other muscle wasting conditions.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

Measurement of respiratory function decline in patients with Duchenne muscular dystrophy: a conjoint analysis

AIM

In Duchenne muscular dystrophy (DMD), little attention has been paid to severity of respiratory function decline (RFD) based on disease progression. We performed a conjoint analysis among 123 Italian clinicians to generate a scale for RFD in DMD patients.

METHODS

Before the interview, 11 attributes were selected by discussion among experts. 32 'patient profiles' were generated. Each physician assessed the severity of RFD for each profile. Each level/attribute was assigned an estimated usefulness to understand its impact on RFD.

RESULTS

The identified attributes were forced vital capacity, forced vital capacity decline, dysphagia, type of ventilation and peak cough flow. These results allowed the development of a scale for RFD severity.

CONCLUSION

This scale can stratify DMD patients according to the severity of their RFD.

Involvement of O-GlcNAcylation in the Skeletal Muscle Physiology and Physiopathology: Focus on Muscle Metabolism

Skeletal muscle represents around 40% of whole body mass. The principal function of skeletal muscle is the conversion of chemical energy toward mechanic energy to ensure the development of force, provide movement and locomotion, and maintain posture. This crucial energy dependence is maintained by the faculty of the skeletal muscle for being a central place as a "reservoir" of amino acids and carbohydrates in the whole body. A fundamental post-translational modification, named O-GlcNAcylation, depends, inter alia, on these nutrients; it consists to the transfer or the removal of a unique monosaccharide (N-acetyl-D-glucosamine) to a serine or threonine hydroxyl group of nucleocytoplasmic and mitochondrial proteins in a dynamic process by the O-GlcNAc Transferase (OGT) and the O-GlcNAcase (OGA), respectively. O-GlcNAcylation has been shown to be strongly involved in crucial intracellular mechanisms through the modulation of signaling pathways, gene expression, or cytoskeletal functions in various organs and tissues, such as the brain, liver, kidney or pancreas, and linked to the etiology of associated diseases. In recent years, several studies were also focused on the role of O-GlcNAcylation in the physiology and the physiopathology of skeletal muscle. These studies were mostly interested in O-GlcNAcylation during muscle exercise or muscle-wasting conditions. Major findings pointed out a different "O-GlcNAc signature" depending on muscle type metabolism at resting, wasting and exercise conditions, as well as depending on acute or long-term exhausting exercise protocol. First insights showed some differential OGT/OGA expression and/or activity associated with some differential stress cellular responses through Reactive Oxygen Species and/or Heat-Shock Proteins. Robust data displayed that these O-GlcNAc changes could lead to (i) a differential modulation of the carbohydrates metabolism, since the majority of enzymes are known to be O-GlcNAcylated, and to (ii) a differential modulation of the protein synthesis/degradation balance since O-GlcNAcylation regulates some key signaling pathways such as Akt/GSK3β, Akt/mTOR, Myogenin/Atrogin-1, Myogenin/Mef2D, Mrf4 and PGC-1α in the skeletal muscle. Finally, such involvement of O-GlcNAcylation in some metabolic processes of the skeletal muscle might be linked to some associated diseases such as type 2 diabetes or neuromuscular diseases showing a critical increase of the global O-GlcNAcylation level.

The experience of parents of adult sons with Duchenne muscular dystrophy regarding their prolonged roles as primary caregivers: a serial qualitative study

PURPOSE

Mechanical ventilation has allowed a greater number of patients with Duchenne muscular dystrophy (DMD) to transition into adulthood. However, the role of a child's parent as a caregiver lasts throughout the child's lifetime. We explored parents' experiences of prolonged caregiving using serial interviews, analyzed using constructivist grounded theory.

MATERIALS AND METHODS

Fourteen parents (average age 53.9 years) with sons with DMD (average age 23.2 years) were interviewed two to four times, over a 3-year period. Data were analyzed using a grounded theory approach.

RESULTS

Two categories of responses were defined as strengths, and four as weaknesses. The strengths were related to family member support and confidence in parenting ability. The weaknesses were related to the anticipation of aging with the ongoing burden of caring for adult sons, regrets, sharing of responsibility versus having a fixed role as the primary caregiver, and economic burden. The weaknesses became more pronounced as the duration of caregiving increased. Parents' acceptance of and immobilization in their role of primary caregiver led to prolonged derivative dependency.

CONCLUSION

Practical support for parental caregivers, who experience a marked increase in the duration of their caregiving role while facing their own aging-related challenges, are required. Implications for Rehabilitation Children with DMD are living longer and are transitioning into adulthood; a successful transition involves becoming as independent as possible and maintaining a positive sense of personal identity. Despite entering adulthood, the parental caregiver's caregiving role continues. Rehabilitation professionals, who are able to provide long-term, continued support from childhood into adulthood, should be aware that parental caregivers' weakness are exacerbated as the duration of caregiving increases. Families affected by DMD require multifaceted support that should include support for the parental caregiver.

Muscle-Bone Interactions in Pediatric Bone Diseases

PURPOSE

Here, we review the skeletal effects of pediatric muscle disorders as well as muscle impairment in pediatric bone disorders.

RECENT FINDINGS

When starting in utero, muscle disorders can lead to congenital multiple contractures. Pediatric-onset muscle weakness such as cerebral palsy, Duchenne muscular dystrophy, spinal muscular atrophy, or spina bifida typically are associated with small diameter of long-bone shafts, low density of metaphyseal bone, and increased fracture incidence in the lower extremities, in particular, the distal femur. Primary bone diseases can affect muscles through generic mechanisms, such as decreased physical activity or in disease-specific ways. For example, the collagen defect underlying the bone fragility of osteogenesis imperfecta may also affect muscle force generation or transmission. Transforming growth factor beta released from bone in Camurati Engelman disease may decrease muscle function.

FUTURE DIRECTIONS

Considering muscle-bone interactions does not only contribute to the understanding of musculoskeletal disorders but also can identify new targets for therapeutic interventions.