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Objectives: In Duchenne muscular dystrophy, quadriceps weakness is recognized as a key factor in gait deterioration. The objective of this work was three-fold: first, to document the strength of the quadriceps in corticosteroid-naïve DMD boys; second, to measure the effect of corticosteroids on quadriceps strength; and third, to evaluate the correlation between baseline quadriceps strength and the age when starting corticosteroids with the loss of ambulation., Methods: Quadriceps muscle strength using hand-held dynamometry was measured in 12 ambulant DMD boys who had never taken corticosteroids and during corticosteroid treatment until the loss of ambulation., Results: Baseline quadriceps muscle strength at 6 years of age was 28% that of normal children of the same age; it decreased to 15% at 8 years and to 6% at 10 years. The increase in quadriceps muscle strength obtained after 1 year of corticosteroid treatment had a strong direct correlation with the baseline strength (R = 0.96). With corticosteroid treatment, the age of ambulation loss showed a very strong direct relationship (R = 0.92) with baseline quadriceps muscle strength but only a very weak inverse relationship (R = -0.73) with the age of starting treatment. Age of loss of ambulation was 10.3 ± 0.5 vs 19.1 ± 4.7 (P < 0.05) in children with baseline quadriceps muscle strength less than or greater than 40 N, respectively., Conclusions: Corticosteroid-naïve DMD boys have a quantifiable severe progressive quadriceps weakness. This long-term study, for the first time, shows that both of the positive effects obtained with CS treatment, i.e. increasing quadriceps strength and delaying the loss of ambulation, have a strong and direct correlation with baseline quadriceps muscle strength. As such, hand-held dynamometry may be a useful tool in the routine physical examination and during clinical trial assessment., Competing Interests: Conflict of interest The Authors declare no conflict of interest, (©2020 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Duchenne muscular dystrophy (DMD) is complicated by an early and progressive left ventricular (LV) dysfunction. Despite the reduction of ejection fraction (EF) usually manifests in the second decade, subtle alterations in LV mechanics can be detected earlier. Longitudinal and circumferential LV deformation, evaluated by speckle tracking echocardiography (STE), are considered sensitive markers of early dysfunction. We retrospectively examined clinical and echocardiographic data of 32 DMD children with preserved LV function. According to the median age, patients were then divided into younger and older than 9 years, and compared to 24 age-matched healthy subjects. Six-minute-walk test (6MWT), North Star Ambulatory Assessment (NSAA), and a comprehensive cardiac evaluation were performed. Although EF was within the normal range, DMD patients had significantly lower values than healthy controls, and the same occurred for the remaining conventional systolic and diastolic indices. Global longitudinal strain (GLS) was reduced in all patients (older and younger, both p < 0.001). Global circumferential strain (GCS) was reduced only in older patients (< 0.001). Both GLS and GCS worsened with age in DMD patients (GLS p = 0.005; GCS p = 0.024). GLS was significantly worse in the apical segments and in the postero-lateral wall. GCS in the antero-septal, anterior and antero-lateral segments was significantly reduced in older patients, with a prevalent involvement of the sole septal wall in the younger boys. 6MWT appeared to be correlated inversely to GLS and directly to EF. A longitudinal evaluation should be scheduled in DMD boys to assess the global cardiac performance over time and to evaluate the impact of therapies., Competing Interests: Conflict of interest The Authors declare no conflict of interest, (©2020 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Objective: The aim of this study was to use a structured questionnaire in a large cohort of Duchenne Muscular Dystrophy (DMD) patients to assess caregivers and patients views on respiratory function and to establish if their responses were related to the patients' age or level of functional impairment., Methods: Questionnaires were administered to caregivers in 205 DMD patients of age between 3 and 36 years (115 ambulant, 90 non-ambulant), and to 64 DMD patients (3 ambulant, 61 non-ambulant) older than 18 years, subdivided into groups according to age, FVC, ambulatory and ventilatory status., Results: Some differences were found in relation to FVC % values ( p = 0.014), ambulatory ( p = 0.043) and ventilatory status ( p = 0.014). Nearly half of the caregivers expected deterioration over the next years, with the perspective of deterioration more often reported by caregivers of non-ambulant ( p = 0.018) and ventilated patients ( p = 0.004). Caregivers appeared to be aware of the relevance of respiratory function on quality of life (84%) showing willingness to enter possible clinical trials if these were aiming to stabilize the progression of respiratory function with a very high number of positive responses across the spectrum of age, FVC, ambulatory and ventilatory status. The boys older than 18 years showed similar results., Conclusions: Our study showed that the concern for respiratory function increases with age and with the reduction of FVC or the need for ventilation, but the need for intervention was acknowledged across the whole spectrum of age and functional status., (©2020 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Different complications of hemostasis have been reported in patients with Duchenne Muscular Dystrophy (DMD). These comprise an increased rate of bleeding-symptoms during scoliosis surgery but also thromboembolic complications such as pulmonary embolism, cerebral infarction, deep vein thrombosis or cardiac thrombus. For this cross-sectional study, personalized online survey-links were forwarded to 682 registered patients with a genetically confirmed diagnosis of DMD via the German-Austrian DMD patient registry (www.dmd-register.de). The questionnaire enquired data regarding the degree of mobility, disposition to hematoma, epistaxis and gum bleeding, occurrence of peri- and postsurgical hemorrhage, stroke, deep vein thrombosis, and cardiac thromboembolism. Further data on regular medication and age were recorded. Three-hundred-fifty-one DMD-patients completed the questionnaire (response rate of 51.5%). Of those, 164 (46.7%) were ambulatory and 187 (53.3%) were non-ambulatory. Age distribution was homogeneous. Two participants had a history of thromboembolic events (0.6%). Correlations analysis revealed no coherence with the degree of mobility, age or regular medication. A bleeding tendency was reported by 76 participants (21.7%). No significant correlations with age or degree of mobility were found. We found no association with underlying genetic variants. Results of this patient registry-based survey do not indicate a distinct DMD-specific risk for thromboembolic events that exceeds the risk by typical comorbidities of chronic immobility and cardiac insufficiency in advanced stages of the disease. The results of this survey suggest a mild bleeding tendency in this DMD cohort, whereas a selection bias cannot be excluded., (©2020 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Background: Duchenne muscular dystrophy (DMD) causes progressive pathologic changes to muscle secondary to a cascade of inflammation, lipid deposition, and fibrosis. Clinically, this manifests as progressive weakness, functional loss, and premature mortality. Though insult to whole muscle groups is well established, less is known about the relationship between intramuscular pathology and function., Objective: Differences of intramuscular heterogeneity across muscle length were assessed using an ordinal MRI grading scale in lower leg muscles of boys with DMD and correlated to patient's functional status., Methods: Cross sectional T 1 weighted MRI images with fat suppression were obtained from ambulatory boys with DMD. Six muscles (tibialis anterior, extensor digitorum longus, peroneus, soleus, medial and lateral gastrocnemii) were graded using an ordinal grading scale over 5 slice sections along the lower leg length. The scores from each slice were combined and results were compared to global motor function and age., Results: Statistically greater differences of involvement were observed at the proximal ends of muscle compared to the midbellies. Multi-slice assessment correlated significantly to age and the Vignos functional scale, whereas single-slice assessment correlated to the Vignos functional scale only. Lastly, differential disease involvement of whole muscle groups and intramuscular heterogeneity were observed amongst similar age subjects., Conclusion: A multi-slice ordinal MRI grading scale revealed that muscles are not uniformly affected, with more advanced disease visible near the tendons in a primarily ambulatory population with DMD. A geographically comprehensive evaluation of the heterogeneously affected muscle in boys with DMD may more accurately assess disease involvement.

Becker muscular dystrophy (BMD) was first described in 1953 by Emile Becker as a benign variant of Duchenne muscular Dystrophy (DMD). Compared with DMD, BMD is clinically more heterogeneous, with initial presentation in the teenage years and loss of ambulation beyond the age of 16 and a wide spectrum of clinical presentations, ranging from only myalgias and muscle cramps to exercise intolerance and myoglobinuria, asymptomatic elevation of serum creatin-kinase, or mild limb-girdle weakness and quadriceps myopathy. About 50% of patients become symptomatic by the age of 10 and the most part by the age of 20 years. However few patients can be free of symptoms till their fifties and cases of late-onset Becker Muscular Dystrophy have also been described. In this report we describe the clinical features of patients with dystrophinopathy sharing a deletion of exons 45-55, occasionally or retrospectively diagnosed. These data are important for both the prognostic aspects of children presenting this dystrophin gene mutation, and for the genetic counseling in these families (reassuring them on the benign course of the disease), and last but not least to keep in mind a diagnosis of BMD in asymptomatic adults with mild hyperckemia.

This study explored the burden in parents and healthy siblings of 4-17 year-old patients with Duchenne (DMD) and Becker (BMD) muscular dystrophies, and whether the burden varied according to clinical aspects and social resources. Data on socio-demographic characteristics, patient's clinical history, parent and healthy children burden, and on parent's social resources were collected using self-reported questionnaires administered to 336 parents of patients with DMD (246) and BMD (90). Parents of patients with DMD reported higher burden than those of patients with BMD, especially concerning feeling of loss (84.3% DMD vs. 57.4% BMD), stigma (44.2% DMD vs. 5.5% BMD) and neglect of hobbies (69.0% DMD vs. 32.5% BMD). Despite the burden, 66% DMD and 62.4% BMD parents stated the caregiving experience had a positive impact on their lives. A minority of parents believed MD has a negative influence on the psychological well-being (31.0% DMD vs. 12.8% BMD), and social life of unaffected children (25.7% vs. 18.4%). In the DMD group, burden correlated with duration of illness and parent age, and burden was higher among parents with lower social contacts and support in emergencies. In DMD, difficulties among healthy children were reported as higher by parents who were older, had higher burden and lower social contacts. In both groups, burden increased in relation to patient disability. These findings underline that the psychological support to be provided to parents of patients with MD, should take into account clinical features of the disease.

The presence of non-progressive cognitive impairment is recognized as a common feature in a substantial proportion of patients with Duchenne muscular dystrophy (DMD). Concurrently, the amyloid beta peptide (Aβ42) protein has been associated with changes in memory and cognitive functions. Also, it has been shown that different subtypes of neural stem/progenitor cells (CD 34, CD 45, nestin) are involved in the innate repair of plasticity mechanisms by the injured brain, in which Nerve Growth Factor (NGF) acts as chemotactic agents to recruit such cells. Accordingly, the present study investigated levels of CD 34, CD 45, nestin and NGF in an attempt to investigate makers of neural regeneration in DMD. Neural damage was assayed in terms of Aβ42. Results showed that Aβ42 (21.9 ± 6.7 vs. 12.13 ± 4.5) was significantly increased among DMD patients compared to controls. NGF (165.8 ± 72 vs. 89.8 ± 35.9) and mononuclear cells expressing nestin (18.9 ± 6 vs. 9 ± 4), CD 45 (64 ± 5.4 vs. 53.3 ± 5.2) and CD34 (75 ± 6.2 vs. 60 ± 4.8) were significantly increased among DMD patients compared to controls. In conclusion cognitive function decline in DMD patients is associated with increased levels of Aβ42, which is suggested to be the cause of brain damage in such patients. The significant increase plasma NFG and in the number of mononuclear cells bearing CD34, CD45 and nestin indicates that regeneration is an ongoing process in these patients. However, this regeneration cannot counterbalance the damage induced by dystrophine mutation and increased Aβ42.

Steroids have been used since two decades and several trials were conducted to establish their efficacy in DMD patients with various regimens. The clinical outcomes showed increased function in the treated boys, and in a single trial with deflazacort, prolongation of ambulation but with different side effects. Steroids clinical efficacy is now established. The main concern is to increase steroid efficacy and decrease side effect and toxicity. A trial comparing daily prednisone, deflazacort and intermittent glucocorticoids (prednisone 10 days on/10 days off) (FOR-DMD) is starting under NIH grant. The primary outcomes will be muscle strength, forced vital capacity and patient/parents satisfaction.

Recently we reported a cytoplasmic sodium overload to cause a severe osmotic oedema in Duchenne muscular dystrophy (DMD). Our results suggested that this dual overload of sodium ions and water precedes the dystrophic process and persists until fatty muscle degeneration is complete. The present paper addresses the questions as to whether these overloads are important for the pathogenesis of the disease, and if so, whether they can be treated. As a first step, we investigated the effects of various diuretic drugs on a cell model of DMD, i.e. rat diaphragm strips previously exposed to amphotericin B. We found that both carbonic anhydrase inhibitors and aldosterone antagonists were able to repolarise depolarised muscle fibres. Since carbonic anhydrase inhibitors are known to have acidifying effects and this might be detrimental to the ventilation of DMD patients, we mainly concentrated on the modern spironolactone derivative, eplerenone. This drug had a very high repolarizing power, the parameter considered by us as being most relevant for a beneficial effect. In a pilot study we administered this drug to a 22-yr-old female DMD patient who was bound to an electric wheelchair and has had no corticosteroid therapy before. Eplerenone decreased both cytoplasmic sodium and water overload and increased muscle strength and mobility. We conclude that eplerenone has beneficial effects on DMD muscle. In our opinion the cytoplasmic oedema is cytotoxic and should be treated before fatty degeneration takes place.

Cardiomyopathy is an almost universal finding in boys affected by Duchenne muscular dystrophy (DMD). Myocardial changes, as a result of the lack of dystrophin, consist of cell membrane degradation, interstitial inflammation, fatty replacement and fibrosis. Dystrophinopathic cardiomyopathy generally starts as a preclinical or intermediate stage, with evolution toward advanced stages characterized by ventricle enlargement but also by symptoms and signs of heart failure (dyspnoea, peripheral edema and liver enlargement). However in few patients the dilation could be the first manifestation of the heart involvement. The ability to detect overt cardiomyopathy increases with age, such that more than 80% of boys older than 18 years will have abnormal systolic function. Several drugs have been employed with the aim to contrast the evolution of cardiomyopathy toward stages of severe congestive heart failure. A review of cardiac treatment in DMD and personal experience are reported and discussed.

Deflazacort is the most commonly prescribed corticosteroid for the treatment of Duchenne muscular dystrophy in Canada. We review the long-term experience with deflazacort treatment at two centers in Canada; Montreal and Toronto. Deflazacort has benefitted both cohorts by prolonged ambulation, preserved cardiac and respiratory function, less scoliosis and improved survival. Common side effects in both cohorts include weight gain, decreased height and cataract formation. The Canadian experience supports the use of deflazacort in treating boys with Duchenne muscular dystrophy.

The purpose of this study is to evaluate whether the range of motion exercise of the temporo-mandibular joint (jaw ROM exercise) with a hot pack and massage of the masseter muscle improve biting disorder in Duchenne muscular dystrophy (DMD). The subjects were 18 DMD patients (21.3+/- 4.1 years old). The jaw ROM exercise consisted of therapist-assisted training (2 times a week) and self-training (before each meal every day). The therapist-assisted training consisted of the application of a hot pack on the cheek of the masseter muscle region (15 minutes), the massage of the masseter (10 minutes), and jaw ROM exercise (5 minutes). The self-training involved jaw ROM exercise by opening the mouth to the maximum degree, ten times. These trainings continued for six months. Outcomes were evaluated by measuring the greatest occlusal force and the distance at the maximum degree of mouth opening between an incisor of the top and that of the bottom. Six months later, the greatest occlusal force had increased significantly compared with that at the start of jaw ROM exercise (intermediate values: from 73.8N to 97.3N) (p = 0.005) as determined by the Friedman test and Scheffi's nonparametric test. The patients' satisfaction with meals increased. However, the maximum degree of mouth opening did not change after six months of jaw ROM exercise. Jaw ROM exercise in DMD is effective for increasing the greatest occlusal force.

Duchenne muscular dystrophy (DMD) is characterized by increased muscle damage and an abnormal blood flow after muscle contraction leading to a state of functional ischemia. Abundant evidence suggests that endothelial circulating progenitor cells (EPCs) play an important role in mediating vascular and muscle repair mechanisms and that the stromal cell-derived factor (SDF)-1 alpha chemokine is responsible for both progenitor cell mobilization from the bone marrow to peripheral blood and homing to the sites of vascular and tissue injury. Since normal neovascularization is disrupted in DMD pathogenesis and may contribute ultimately to heart failure and sudden death, the aim of the present study is to investigate whether the (SDF)-1 alpha, and EPCs surface receptors in terms of CD34, CD133 and kinase domain receptor (KDR) are involved in DMD pathophysiology. In the present study, peripheral blood concentrations of circulating CD34, CD133, and CD34/ CD 133 progenitor cells were measured by flow cytometry, together with serum levels of (SDF)-1alpha and hypoxia inducible factor (HIF-1alpha.), in 28 DMD patients vs. 20 healthy age and socioeconomic matching controls. Results showed a significant increase in the number of mononuclear cells bearing EPC markers, HIF-1alpha mRNA expression and serum (SDF)-1 alpha, indicating that regeneration is an ongoing process in these patients. However, this regeneration cannot counterbalance the damage induced by dystrophine mutation.

Dystrophin deficiency associated with Duchenne muscular dystrophy (DMD) results in chronic inflammation and severe skeletal muscle degeneration, where the extent of muscle fibrosis contributes to disease severity. The microenvironment of dystrophic muscles is associated with variation in levels of markers of degeneration and regeneration. Since in dystrophic muscle apoptosis precedes necrosis, markers of apoptosis can be used as indicators of degeneration, while regeneration can be measured in terms of cytokines and growth factor expression"; and then throughout the text use "markers of apoptosis/degeneration. The present study is an attempt to evaluate the extent of degeneration and regeneration in DMD patient blood. Subjects were 24 boys with DMD diagnosed at the molecular level versus 20 age and socioeconomic matching healthy boys. In their blood, levels of Fas and FasL and Bax/Bcl-2 and plasma DNA fragmentation were measured as markers of apoptosis. The cytokine tumor necrosis factor alfa (TNF-alpha), and the growth factors: basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were measured as markers of regeneration. Plasma DNA fragmentation (0.38% +/- 0.12 vs. 0.2% +/- 0.15) and Fas (9.9 +/- 2.8 vs. 2 +/- 0.1, p < 0.001) together with FasL mRNA expression in circulating lymphocytes (0.47 +/- .09 vs. 0.24 +/- .04, p < 0.001) were significantly increased in DMD patients compared to controls. There was a significant increase in Bax (0.19 +/- 0.7 vs. 0.05 +/- 0.1, p < 0.00001) expression and a significant decrease in Bcl-2 protein (6.4 +/- 1.6 vs 10 +/- 2.8, p < 0.00001) as compared to controls. Among markers of regeneration, TNF- alpha (30.2 +/- 9.5 vs. 3.6 +/- 0.9) and bFGF (21.7 +/- 10.3 vs. 4.75 +/- 2.2) were significant increased while VEGF was significantly decreased (190 +/- 115 vs. 210 +/- 142.) in blood of DMD patients compared to controls. Our results indicate that Fas/FasL and Bax/Bcl-2 are involved in muscle atrophy and degeneration in DMD patients, while regeneration process does not cope with the degeneration.

Unlabelled: Replicative aging and oxidative stress are two plausible theories explaining the etiology of muscular dystrophy. The first theory indicates that replicative aging of myogenic cells (satellite cells), owing to enhanced myofiber turnover, is a plausible explanation of the progression of Duchenne muscular dystrophy (DMD). The oxidative stress theory indicates that failure of muscle regeneration to keep up with the ongoing apoptosis and necrosis following oxidative stress, that normally associates muscular exercise, leads to muscle atrophy in DMD. To test for these two theories, markers of replicative aging and oxidative stress were assessed in the blood of 30 DMD patients vs. 20 normal healthy age matching controls. Markers of replicative aging showed significantly lower telomerase activity, significantly increased expression of receptors for advanced glycation end products (RAGEs) mRNA and Bax mRNA (an apoptotic gene) in DMD compared to controls. There was a significant increase in markers of oxidative stress among DMD patients compared to controls, measured in terms of increased apoptotic percentage in circulating mononuclear cells, increased lipid peroxidation measured in terms of plasma malondialdehyde (MDA) and increased protein carbonyls. Levels of plasma nitric oxide (NO), which neutralizes oxygen radicals, and expression of inducible nitric oxide synthase (iNOS) mRNA in neutrophils was significantly lower among DMD compared to controls. Biostimulation of WBC by helium neon (He:Ne) laser irradiation induced a significant increase in the expression of iNOS mRNA and plasma NO levels, but still at a lower level compared to controls. He:Ne laser irradiation induced a marked decrease in markers of oxidative stress among DMD patients compared to their level before irradiation, measured in terms of decreased plasma protein carbonyls, decreased plasma MDA, and decreased apoptosis percentage., Conclusion: This study points to that oxidative stress is the prime cause for muscle degeneration in DMD and points out to the possible ameliorative effect of He:Ne laser on this

Animal models of DMD have played, and will continue to play, a key role in the understanding of the pathogenesis and treatment of Duchenne muscular dystrophy (DMD). The mdx mouse and GRMD dog are spontaneous dystrophin deficient mutants and have been the most widely used models to date. A number of other murine models have been created by exposure to mutagens or genetic manipulation. The animal models have allowed the development of a number of promising experimental therapeutic approaches to DMD that are now entering clinical trial, the majority of which would not have been developed without their use. However, there has been much debate about the merits of the different animal models, which will only be finally clear as we learn from the initial human clinical trials.

Over the past decade, signalling cascades have been characterised that control key features of muscle growth, including the proliferation, differentiation of muscle precursors, the control cell size (hypertrophy) and cell death. In this review we highlight how two differing signalling molecules, Insulin-like Growth Factor-1 (IGF-1) and myostatin, regulate key steps during muscle development. We discuss how IGF-1 and myostatin signalling cascades can be manipulated to stimulate muscle growth. We summarise experimental data from mdx mouse, the animal model for Duchenne muscular dystrophy, that suggest a therapeutic value of these strategies for patients suffering from muscular dystrophy without redressing the primary cause of the lesion.

In progressive muscular dystrophy, such as Duchenne muscular dystrophy, muscles show the pathological changes characterized by hypertrophy at the early phase, while atrophic changes are seen with aging. As an experimental model for muscle hypertrophy and atrophy, insulin-like growth factor-1 (IGF-1) signaling via the activation of PI3K/Akt pathway has been well characterized. IGF-1 is also highlighted as a therapeutic agent as it has been shown to improve phenotype of dystrophic animals. In this review, the functions of IGF-1 on mitogenic proliferation and myogenic differentiation in vitro, muscle hypertrophy in vivo are discussed, as well as its possible utility for molecular therapy on muscular dystrophies.

Dystrophin is a protein responsible for a severe muscle disease Duchenne muscular dystrophy (DMD). This molecule, a huge 427 kDa protein, is also expressed in brain neurons, but its function in the central nervous system (CNS) has been obscure. It is known that some DMD patients have accompanying symptoms of CNS disorders such as the cognitive impairment or psychiatric disorders. The bases of the CNS symptoms are unknown. Addressing the CNS function of dystrophin would make the advance on the interpretation of the CNS symptoms accompanying with DMD. In this short review, previous findings on dystrophin in the CNS are summarized to facilitate studies on the CNS function of this molecule. Following topics are in particular focused, (1) regional and subcellular distribution of dystrophin in the brain and the function in GABAergic synapses, (2) the CNS abnormality in dystrophin-deficient 'mdx' mice.

An electrocardiographic pattern resembling myocardial infarction is a rare condition in Duchenne muscular dystrophy. We report the case of a Duchenne boy, aged 12 years and 7 month, who, during a programmed examination, showed electrocardiographic signs of ST segment elevation, without symptoms usually accompanying myocardial infarction (chest pain, dyspnoea, sweating). The biological markers of myocardial damage became positive on the 2nd day and recovered on the 5th day. Clinical features of this uncommon pattern are described, with the retrospective evaluation of similar cases from personal records. The differential diagnosis between myocardial necrosis and apoptosis is discussed.