Diagnosis delay of Duchenne Muscular Dystrophy

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.

Perfil clínico e funcional dos pacientes com Distrofia Muscular de Duchenne assistidos na Associação Brasileira de Distrofia Muscular (ABDIM)

A distrofia muscular de Duchenne (DMD) é uma doença hereditária progressiva, de herança recessiva ligada ao cromossomo X. As manifestações clínicas se iniciam na infância com enfraquecimento muscular progressivo. Objetivo: Foi caracterizar o perfil clínico e funcional apresentado pelos pacientes com DMD, que se encontravam em acompanhamento na Associação Brasileira de Distrofia Muscular (ABDIM). Método: Foram coletados os dados de 58 pacientes com o diagnóstico de DMD. Resultados: Os resultados obtidos caracterizaram os pacientes com DMD da ABDIM, proporcionando dados como: idade da população, complicações clínicas mais freqüentes e nível de independência em relação á funcionalidade, caracterizando a diversidade do perfil clínico e funcional desses pacientes. Conclusão: Concluiu-se que o perfil clínico e funcional dos pacientes da ABDIM apresentou-se heterogêneo, mostrando que a progressão da doença varia de sujeito para sujeito dentro da população estudada, mesmo levando em consideração a faixa etária.

Arquitetura comparativa dos pulmões de camundongos normais e afetados pela Distrofia Muscular de Duchenne

Resumo: A Distrofia Muscular de Duchenne (DMD) é uma doença genética de caráter recessivo que caracterizada por fraqueza muscular progressiva de cintura pélvica e escapular evoluindo para insuficiência respiratória e, ou cardíaca. O camundongo mdx é um modelo amplamente utilizado para estudos da DMD. Apesar do fenótipo destes animais serem mais suave, estes apresentam o principal músculo respiratório, o diafragma com morfologia e bioquímica semelhante à DMD humana, fato este que pode comprometer a função respiratória e consequentemente os pulmões. Foi realizado um estudo anatômico descritivo do parênquima pulmonar dos pulmões de 5 animais modelo mdx comparando estes com os pulmões de 5 camundongos BALB/C57 (Mus musculus). Os pulmões foram analisados macroscopicamente e através de microscopia de luz e eletrônica de varredura. Os achados sugerem que o modelo mdx apresenta morfologia pulmonar semelhante aos camundongos BALB/C57 e que seu uso deve ser cauteloso e criterioso em ensaios clínicos que aborde este órgão.

Laparoscopic guided local injection in the X-linked muscular dystrophy mouse (mdx) diaphragm. An advance in experimental therapies for Duchenne Muscular Dystrophy

PURPOSE

To investigate the development of a laparoscopy technique for local injection into the X-linked muscular dystrophy (mdx) diaphragm.

METHODS

It was used 10 mice Balb/C57 and 5 mdx mice and three differents decubitus type were tested: the right lateral, supine, and supine decubitus with 20 degrees elevation of the forelimb. Abdominal caudal face and the 10 intercostal space were tested as spot to introduce the needle into the diaphragm.

RESULTS

Supine position with elevation of 20 degrees forelimb and the 10th intercostal space are the beneficial position to apply a local injection.

CONCLUSION

It was proved to be possible to perform the laparoscopy technique in the X-linked muscular dystrophy diaphragm and this requires a specific position and technique during the surgery.

Muscle reorganisation through local injection of stem cells in the diaphragm of mdx mice

Background

The diaphragm is the major respiratory muscle affected by Duchenne muscular dystrophy (DMD) and is responsible for causing 80% of deaths. The use of mechanical forces that act on the body or intermittent pressure on the airways improves the quality of life of patients but does not prevent the progression of respiratory failure. Thus, diseases that require tissue repair, such as DMD, represent a group of pathologies that have great potential for cell therapy. The application of stem cells directly into the diaphragm instead of systemic application can reduce cell migration to other affected areas and increase the chances of muscle reorganisation. The mdx mouse is a suitable animal model for this research because its diaphragmatic phenotype is similar to human DMD. Therefore, the aim of this study was to assess the potential cell implantation in the diaphragm muscle after the xenotransplantation of stem cells.

Methods

A total of 9 mice, including 3 control BALB/Cmice, 3 5-month-old mdx mice without stem cell injections and 3 mdx mice injected with stem cells, were used. The animals injected with stem cells underwent laparoscopy so that stem cells from GFP-labelled rabbit olfactory epithelium could be locally injected into the diaphragm muscle. After 8 days, all animals were euthanised, and the diaphragm muscle was dissected and subjected to histological and immunohistochemical analyses.

Results

Both the fresh diaphragm tissue and immunohistochemical analyses showed immunopositive GFP labelling of some of the cells and immunonegativity of myoblast bundles. In the histological analysis, we observed a reduction in the inflammatory infiltrate as well as the presence of a few peripheral nuclei and myoblast bundles.

Conclusion

We were able to implant stem cells into the diaphragm via local injection, which promoted moderate muscle reorganisation. The presence of myoblast bundles cannot be attributed to stem cell incorporation because there was no immunopositive labelling in this structure. It is believed that the formation of the bundles may have been stimulated by cellular signalling mechanisms that have not yet been elucidated.

Correlação da massa e porcentagem de gordura com a idade na distrofia muscular de Duchenne

INTRODUÇÃO: A Distrofia Muscular de Duchenne (DMD) é uma desordem genética, caracterizada pela perda progressiva e irreversível da musculatura esquelética. OBJETIVO: Este estudo objetiva correlacionar a porcentagem e a massa de gordura com a idade em pacientes com DMD. METODOLOGIA: Foram selecionados 68 indivíduos com idades entre 5 e 20 anos, com diagnóstico molecular de certeza para DMD, residentes na cidade de São Paulo. Todos foram submetidos à mensuração do peso e altura e também ao teste de análise de composição corporal com o uso da bioimpedância, no período da manhã, todas no mesmo dia. RESULTADOS E DISCUSSÃO: Os resultados foram analisados agrupando os indivíduos em quartis de idade e mostraram um índice de massa corpóreo (IMC) de 21 ± 8 kg/m². Assim, observou-se que, com a idade e o grau de sedentarismo imposto pela doença, houve um acúmulo de gordura corporal e perda de massa magra. CONCLUSÃO: São necessários mais estudos relacionados às características nutricionais desses indivíduos, para que se esclareçam melhor os efeitos da doença e da alimentação no ganho de porcentagem e massa de gordura.