Brazilian consensus on Duchenne muscular dystrophy. Part 1: diagnosis, steroid therapy and perspectives

Persistent inflammation and nutritional status in Duchenne muscular dystrophy

BACKGROUND & AIMS

Duchenne muscular dystrophy (DMD) involves muscle fragility, sarcolemma instability, and chronic inflammation. This study aims to identify the inflammatory profile of DMD patients and evaluate associations between clinical and nutritional variables.

METHODS

We performed a cross-sectional study nested in a cohort to obtain sociodemographics, illness time, use of medications, and supplement data through interviews and the patient's medical records. Then, we assessed the relationships between illness time, cytokine levels, and nutritional status.

RESULTS

Forty-four male participants, aged 4.3-24.2 years, were evaluated. Concerning nutritional status, 18 participants were eutrophic. The fat mass increased and the lean mass decreased from the beginning of the first signs of DMD. Cytokines levels in DMD patients, even under corticosteroids therapy, are higher than values described in the literature on healthy subjects. The regression models demonstrated that illness time and BMI/A z-scores are associated with higher values of interleukin-6.

CONCLUSIONS

A persistent inflammatory profile was observed in the patients evaluated. The data suggest that maintaining adequate nutritional status and body composition is important for determining the inflammation presented by individuals with DMD.

Clinical practice guidelines for the diagnosis and management of Duchenne muscular dystrophy: a scoping review

Introduction

Our objective was to identify recent CPGs for the diagnosis and management of DMD and summarize their characteristics and reliability.

Methods

We conducted a scoping review of CPGs using MEDLINE, the Turning Research Into Practice (TRIP) database, Google Scholar, guidelines created by organizations, and other repositories to identify CPGs published in the last 5 years. Our protocol was drafted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses for scoping reviews. To assess the reliability of the CPGs, we used all the domains included in the Appraisal of Guidelines Research and Evaluation II.

Results

We selected three CPGs published or updated between 2015 and 2020. All the guidelines showed good or adequate methodological rigor but presented pitfalls in stakeholder involvement and applicability domains. Recommendations were coherent across CPGs on steroid treatment, except for minor differences in dosing regimens. However, the recommendations were different for new drugs.

Discussion

There is a need for current and reliable CPGs that develop broad topics on the management of DMD and consider the challenges of developing recommendations for RDs.

Estimated costs for Duchenne muscular dystrophy care in Brazil

BACKGROUND

The economic burden of rare diseases on health systems is still not widely measured, with the generation of accurate information about the costs with medical care for subjects with rare diseases being crucial when defining health policies. Duchenne Muscular Dystrophy (DMD) is the most common form of muscular dystrophy, with new technologies recently being studied for its management. Information about the costs related to the disease in Latin America is scarce, and the objective of this study is to evaluate the annual hospital, home care and transportation costs per patient with DMD treatment in Brazil.

RESULTS

Data from 27 patients were included, the median annual cost per patient was R$ 17,121 (IQR R$ 6,786; 25,621). Home care expenditures accounted for 92% of the total costs, followed by hospital costs (6%) and transportation costs (2%). Medications and loss of family, and patient's productivity are among the most representative consumption items. When disease worsening due to loss of the ability to walk was incorporated to the analysis, it was shown that wheelchair users account for an incremental cost of 23% compared with non-wheelchair users.

CONCLUSIONS

This is an original study in Latin America to measure DMD costs using the micro-costing technique. Generating accurate information about costs is crucial to provide health managers with information that could help establish more sustainable policies when deciding upon rare diseases in emerging countries.

Duchenne muscular dystrophy progression induced by downhill running is accompanied by increased endomysial fibrosis and oxidative damage DNA in muscle of mdx mice

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle necrosis. One of the major challenges for prescribing physical rehabilitation exercises for DMD patients is associated with the lack of a thorough knowledge of dystrophic muscle responsiveness to exercise. This study aims to understand the relationship between myogenic regulation, inflammation and oxidative stress parameters, and disease progression induced by downhill running in the skeletal muscle of an experimental model of DMD. Six-month-old C57BL/10 and C57BL/10-DMD^mdx male mice were distributed into three groups: Control (C), mdx, and mdx + Exercise (mdx + Ex). Animals were trained in a downhill running protocol for seven weeks. The gastrocnemius muscle was subjected to histopathology, muscle regeneration (myoD and myogenin), inflammation (COX-2), oxidative stress (8-OHdG) immunohistochemistry markers, and gene expression (qPCR) of NF-kB and NADP(H)Oxidase 2 (NOX-2) analysis. In the mdx + Ex group, the gastrocnemius muscle showed a higher incidence of endomysial fibrosis and a lower myonecrosis percentage area. Immunohistochemical analysis revealed decreased myogenin immunoexpression in the mdx group, as well as accentuated immunoexpression of nuclear 8-OHdG in both mdx groups and increase in cytoplasmic 8-OHdG only in the mdx + Ex. COX-2 immunoexpression was related to areas of regeneration process and inflammatory infiltrate in the mdx group, while associated with areas of muscle fibrosis in the mdx + Ex. Moreover, the NF-kB gene expression was not influenced by exercise; however, a NAD(P)HOxidase 2 increase was observed. Oxidative stress and oxidative DNA damage play a significant role in the DMD phenotype progression induced by exercise, compromising cellular patterns resulting in increased endomysial fibrosis.

Creatine kinase test diagnostic accuracy in neonatal screening for Duchenne Muscular Dystrophy: A systematic review

OBJECTIVES

to evaluate the accuracy of the creatine kinase test in neonatal screening for Duchenne Muscular Dystrophy.

METHODS

Investigations were carried out in six databases, gray literature and manual search. All studies and data extraction eligibility processes were carried out in paired mode. The methodological stringency of the studies was assessed using the modified QUADAS 2 tool. The performance measures of the test were calculated using the Meta-DiSc software, version 1.4.

RESULTS

11 studies were included, with a total sample of 1,416,123 newborns. The positive likelihood ratio was more than 10 in these studies. On the other hand, the negative likelihood ratio was up to 0.2 in 9/10 studies; however, when considering the upper limit of the confidence interval, only 4/10 studies showed a negative likelihood ratio less than 0.2 and in 6/11 it was greater than 0.5. Specificity was close to 1 in studies. The sensitivity was equal to or greater than 0.81 in 10/11 studies; however, when considering the reliability's minimum interval limit, only 6/10 studies showed sensitivity equal to or greater than 0.7. Ten studies were summarized on a ROC curve indicating good performance (Area under the curve = 0.9980 and Q index = 0.9846).

CONCLUSIONS

the creatine kinase test showed good accuracy in screening for cases of Duchenne Muscular Dystrophy and may be a useful alternative in the early diagnosis of the disease followed by confirmatory genetic testing.

Duchenne muscular dystrophy: an overview to the cardiologist

INTRODUCTION

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in children, affecting approximately one in 3,500-5,000 liveborn boys. The main signs and symptoms include gait disturbances beginning in early childhood, with later onset of respiratory and cardiac function disorders, both directly affecting the prognosis.

AREAS COVERED

The recent improvement of mechanical ventilation increased the mean DMD survival age; however, there has been little progress in the treatment and prevention of cardiac complications, which currently predominantly impact survival. Cardiological evaluation with imaging methods, such as echocardiography and magnetic resonance imaging, can improve the understanding and detect changes in cardiac function early.

EXPERT OPINION

Close monitoring by the cardiologists and early treatment, with adequate heart disease stratification, may be the key to prolong the lives of these patients until more promising therapies are available and can predict DMD prognosis and progression more accurately. The objective of this brief review is to update the cardiologists by highlighting the most relevant aspects of treatment and follow-up, in a practical and concise way.

Can simple and low-cost motor function assessments help in the diagnostic suspicion of Duchenne muscular dystrophy?

OBJECTIVE

Duchenne muscular dystrophy, an X-linked genetic disease, leads to progressive muscle weakness mainly in the lower limbs. Motor function tests help to monitor disease progression. Can low-cost, simple assessments help in the diagnostic suspicion of Duchenne muscular dystrophy? The authors aim to define the sensitivity of time to rise from the floor, time to walk 10meters, and time to run 10meters, evaluating them as eventual diagnostic screening tools.

METHODS

This is an analytical, observational, retrospective (1998-2015), and prospective study (2015-2018). Cases were recruited from the database of the pediatric neurology department and the healthy, from child care consultations, with normal gait development (up to 15 months) and without other comorbidities (neuromuscular, pulmonary, heart diseases) from the same university hospital.

RESULTS

128 Duchenne muscular dystrophy patients and 344 healthy children were analyzed, equally distributed in age groups. In Duchenne muscular dystrophy, there is a progressive increase in the means of the times to perform the motor tests according to the age group, which accelerates very abruptly after 7 years of age. Healthy children acquire maximum motor capacity at 6 years and stabilize their times. The time to rise showed a p-value <0.05 and a strong association (effect size [ES] >0.8) in all age groups (except at 12 years), with time to walk 10 meters from 9 years, and with time to run 10 meters , from 5 years. The 100% sensitivity points were defined as follows: time to rise, at 2s; time to walk 10 meters, 5s; time to run 10 meters, 4s.

CONCLUSIONS

Time to rise is a useful and simple tool in the screening of neuromuscular disorders such as Duchenne muscular dystrophy, a previously incurable disease with new perspectives for treatment.

New developments in pharmacotherapy for Friedreich ataxia

Introduction: Friedreich ataxia (FRDA), a rare disease caused by the deficiency of the mitochondrial matrix protein frataxin, affects roughly 1 in 50,000 individuals worldwide. Current and emerging therapies focus on reversing the deleterious effects of such deficiency including mitochondrial augmentation and increasing frataxin levels, providing the possibility of treatment options for this physiologically complex, multisystem disorder. Areas covered: In this review article, the authors discuss the current and prior in vivo and in vitro research studies related to the treatment of FRDA, with a particular interest in future implications of each therapy. Expert opinion: Since the discovery of FXN in 1996, multiple clinical trials have occurred or are currently occurring; at a rapid pace for a rare disease. These trials have been directed at the augmentation of mitochondrial function and/or alleviation of symptoms and are not regarded as potential cures in FRDA. Either a combination of therapies or a drug that replaces or increases the pathologically low levels of frataxin better represent potential cures in FRDA.

Bioelectrical impedance vector analysis and phase angle in boys with Duchenne muscular dystrophy

Background

Duchenne muscular dystrophy (DMD) is a disease characterized by progressive loss of functional muscle mass followed by changes in body composition.

Objective

This study aimed to describe and evaluate bioimpedance parameters in boys with DMD.

Design

This cross-sectional, descriptive study investigated children and adolescents diagnosed with DMD. Age, weight, height, resistance, and reactance data were collected. Phase angle and bioelectrical impedance vector analysis were calculated based on resistance and reactance values.

Results

We analyzed 43 boys aged between 2.7 and 19.8 years. Low-phase angle values were observed during the investigation of bioimpedance parameters. Bioelectrical impedance vector analysis showed that approximately 87% of the subjects presented vectors outside the tolerance ellipses, and only one patient presented vectors located within the 50% tolerance ellipse, indicating normally hydrated and a good body cell mass. Compared with the reference population, boys with DMD had lower levels of body cell mass.

Conclusion

Based on the evidence, compared with the reference population, patients with DMD had lower levels of body cell mass. This evidence points to bioimpedance parameters as useful tools for the nutritional evaluation and clinical management of patients with DMD.

Brazilian consensus on Duchenne muscular dystrophy. Part 2: rehabilitation and systemic care

ABSTRACT Significant advances in the understanding and management of Duchenne muscular dystrophy (DMD) have occurred since the publication of international guidelines for DMD care in 2010. Our objective was to provide an evidence-based national consensus statement for multidisciplinary care of DMD in Brazil. A combination of the Delphi technique with a systematic review of studies from 2010 to 2016 was employed to classify evidence levels and grade of recommendations for the guideline. Our recommendations were divided in two parts. Guideline methodology and overall disease concept descriptions are found in Part 1. Here we present Part 2, where we provide the results and recommendations on rehabilitation and systemic care for DMD.