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Wong BL, Summer S, Horn PS, Rutter MM, Rybalsky I, Tian C, Shellenbarger KC, Kalkwarf HJ. Appendicular lean mass index changes in patients with Duchenne muscular dystrophy and Becker muscular dystrophy. J Cachexia Sarcopenia Muscle 2023; 14:2804-2812. [PMID: 37878526 PMCID: PMC10751441 DOI: 10.1002/jcsm.13357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/05/2023] [Accepted: 09/18/2023] [Indexed: 10/27/2023] Open
Abstract
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.
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Affiliation(s)
- Brenda L. Wong
- Department of Pediatrics and Neurology, DMD ProgramUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Suzanne Summer
- Clinical Translational Research CenterCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
| | - Paul S. Horn
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOHUSA
| | - Meilan M. Rutter
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOHUSA
- Division of EndocrinologyCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
| | - Irina Rybalsky
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
| | - Cuixia Tian
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOHUSA
| | - Karen C. Shellenbarger
- Department of Pediatrics and Neurology, DMD ProgramUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Heidi J. Kalkwarf
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOHUSA
- Division of Gastroenterology, Hepatology and NutritionCincinnati Children's Hospital Medical CenterCincinnatiOHUSA
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Suslov VM, Lieberman LN, Carlier PG, Ponomarenko GN, Ivanov DO, Rudenko DI, Suslova GA, Adulas EI. Efficacy and safety of hydrokinesitherapy in patients with dystrophinopathy. Front Neurol 2023; 14:1230770. [PMID: 37564736 PMCID: PMC10410449 DOI: 10.3389/fneur.2023.1230770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/05/2023] [Indexed: 08/12/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is one of the most common forms of hereditary muscular dystrophies in childhood and is characterized by steady progression and early disability. It is known that physical therapy can slow down the rate of progression of the disease. According to global recommendations, pool exercises, along with stretching, are preferable for children with DMD, as these types of activities have a balanced effect on skeletal muscles and allow simultaneous breathing exercises. The present study aimed to evaluate the effectiveness of regular pool exercises in patients with Duchenne muscular dystrophy who are capable of independent movement during 4 months of training. 28 patients with genetically confirmed Duchenne muscular dystrophy, who were aged 6.9 ± 0.2 years, were examined. A 6-min distance walking test and timed tests, namely, rising from the floor, 10-meter running, and stair climbing and descending, muscle strength of the upper and lower extremities were assessed on the baseline and during dynamic observation at 2 and 4 months. Hydrorehabilitation course lasted 4 months and was divided into two stages: preparatory and training (depend on individual functional heart reserve (IFHR)). Set of exercises included pool dynamic aerobic exercises. Quantitative muscle MRI of the pelvic girdle and thigh was performed six times: before training (further BT) and after training (further AT) during all course. According to the results of the study, a statistically significant improvement was identified in a 6-min walking test, with 462.7 ± 6.2 m on the baseline and 492.0 ± 6.4 m after 4 months (p < 0.001). The results from the timed functional tests were as follows: rising from the floor test, 4.5 ± 0.3 s on the baseline and 3.8 ± 0.2 s after 4 months (p < 0.001); 10 meter distance running test, 4.9 ± 0.1 s on the baseline and 4.3 ± 0.1 s after 4 months (p < 0.001); 4-stair climbing test, 3.7 ± 0.2 s on the baseline and 3.2 ± 0.2 s after 4 months (p < 0.001); and 4-stair descent test, 3.9 ± 0.1 s on the baseline and 3.2 ± 0.1 s after 4 months (p < 0.001). Skeletal muscle quantitative MRI was performed in the pelvis and the thighs in order to assess the impact of the procedures on the muscle structure. Muscle water T2, a biomarker of disease activity, did not show any change during the training period, suggesting the absence of deleterious effects and negative impact on disease activity. Thus, a set of dynamic aerobic exercises in water can be regarded as effective and safe for patients with DMD.
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Affiliation(s)
- V. M. Suslov
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
| | - L. N. Lieberman
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
| | - P. G. Carlier
- University Paris-Saclay, CEA, Frédéric Joliot Institute for Life Sciences, SHFJ, Orsay, France
| | - G. N. Ponomarenko
- Federal State Budgetary Institution Federal Scientific Center of the Rehabilitation of the Disabled Named After G. A.Albrecht of the Ministry of Labour and Social Protection of the Russian Federation, Saint Petersburg, Russia
| | - D. O. Ivanov
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
| | - D. I. Rudenko
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
| | - G. A. Suslova
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
| | - E. I. Adulas
- Department of Rehabilitation, Federal State Budgetary Educational Institution of Higher Education Saint-Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation, Saint Petersburg, Russia
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Ishii MN, Nakashima M, Kamiguchi H, Zach N, Kuboki R, Baba R, Hirakawa T, Suzuki K, Quinton M. Urine titin as a novel biomarker for Duchenne muscular dystrophy. Neuromuscul Disord 2023; 33:302-308. [PMID: 36871413 DOI: 10.1016/j.nmd.2023.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/10/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is the most severe form of muscular dystrophy that is caused by lack of dystrophin, a critical structural protein in skeletal muscle. DMD treatments, and quantitative biomarkers to assess the efficacy of potential treatments, are urgently needed. Previous evidence has shown that titin, a muscle cell protein, is increased in the urine of patients with DMD, suggesting its usefulness as a DMD biomarker. Here, we demonstrated that the elevated titin in urine is directly associated with the lack of dystrophin and urine titin responses to drug treatment. We performed a drug intervention study using mdx mice, a DMD mouse model. We showed that mdx mice, which lack dystrophin due to a mutation in exon 23 of the Dmd gene, have elevated urine titin. Treatment with an exon skipper that targets exon 23 rescued muscle dystrophin level and dramatically decreased urine titin in mdx mice and correlates with dystrophin expression. We also demonstrated that titin levels were significantly increased in the urine of patients with DMD. This suggests that elevated urine titin level might be a hallmark of DMD and a useful pharmacodynamic marker for therapies designed to restore dystrophin levels.
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Affiliation(s)
- Misawa Niki Ishii
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan.
| | - Masato Nakashima
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Hidenori Kamiguchi
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Neta Zach
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, US, 350 Massachusetts Ave Cambridge, MA 02139, United Kingdom
| | - Ryosuke Kuboki
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Rina Baba
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Takeshi Hirakawa
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Kazunori Suzuki
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Tokyo, 251-0012, 26-1, 2-chome, Higashimuraoka, Fujisawa, Kanagawa, Japan
| | - Maria Quinton
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, US, 350 Massachusetts Ave Cambridge, MA 02139, United Kingdom
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Pasca L, Gardani A, Paoletti M, Velardo D, Berardinelli A. Good response to the late treatment with ataluren in a boy with Duchenne muscular dystrophy: could the previous mild course of the disease have affected the outcome? ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2022; 41:121-125. [PMID: 36349184 PMCID: PMC9628801 DOI: 10.36185/2532-1900-078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a severe, progressive X-linked recessive disorder, caused by the absence of the dystrophin protein. A resolutive therapy for DMD is not yet available. The first approved drug for DMD patients with nonsense mutations is ataluren, approved for the treatment of children aged ≥ 2 yrs, that seems effective in slowing the disease progression. An earlier introduction of ataluren seems to give better results. We report the case of a 14-year-old DMD patient with a nonsense mutation in exon 70, still ambulant, who started taking ataluren at 12 years and remained stable for the following two years. The patient was on steroid since the age of 6, with beneficial effects. At two-years follow-up, an optimal disease evolution was observed, associated with a constant decrease of creatine kinase blood levels. Despite the late start of the treatment, ataluren seems to have significantly contributed to the stabilization of the functional status in this patient though it cannot be excluded that the result may have been influenced by the previous favorable course of the disease. However, further studies should be planned in patients with similar age treated with ataluren to better evaluate the treatment's results compared to the natural course of the disease.
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Affiliation(s)
- Ludovica Pasca
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Pavia, Italy, Department of Brain and Behaviour Neuroscience, University of Pavia, Pavia, Italy
| | - Alice Gardani
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Pavia, Italy
| | - Matteo Paoletti
- Department of Neuroradiology, IRCCS Mondino Foundation, Pavia, Italy
| | - Daniele Velardo
- IRCCS Foundation Ca’ Granda Ospedale Maggiore Policlinico; Neurology Unit, Milan, Italy
| | - Angela Berardinelli
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Pavia, Italy,Correspondence Angela Berardinelli Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, via Mondino 2, 27100 Pavia, Italy. E-mail:
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Can simple and low-cost motor function assessments help in the diagnostic suspicion of Duchenne muscular dystrophy? JORNAL DE PEDIATRIA (VERSÃO EM PORTUGUÊS) 2020. [DOI: 10.1016/j.jpedp.2019.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Pereira AC, Araújo APDQC, Ribeiro MG. Can simple and low-cost motor function assessments help in the diagnostic suspicion of Duchenne muscular dystrophy? J Pediatr (Rio J) 2020; 96:503-510. [PMID: 31009620 PMCID: PMC9432257 DOI: 10.1016/j.jped.2019.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/25/2019] [Accepted: 02/18/2019] [Indexed: 11/21/2022] Open
Abstract
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.
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Affiliation(s)
- Aline Chacon Pereira
- Universidade Federal do Rio de Janeiro (UFRJ), Departamento de Pediatria, Neuropediatria, Rio de Janeiro, RJ, Brazil.
| | | | - Márcia Gonçalves Ribeiro
- Universidade Federal do Rio de Janeiro (UFRJ), Departamento de Pediatria, Genética Clínica, Rio de Janeiro, RJ, Brazil
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Lennie JL, Mondick JT, Gastonguay MR. Latent process model of the 6-minute walk test in Duchenne muscular dystrophy : A Bayesian approach to quantifying rare disease progression. J Pharmacokinet Pharmacodyn 2020; 47:91-104. [PMID: 31960231 DOI: 10.1007/s10928-020-09671-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/05/2020] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a rare X-linked genetic pediatric disease characterized by a lack of functional dystrophin production in the body, resulting in muscle deterioration. Lower body muscle weakness progresses to non-ambulation typically by early teenage years, followed by upper body muscle deterioration and ultimately death by the late twenties. The objective of this study was to enhance the quantitative understanding of DMD disease progression through nonlinear mixed effects modeling of the population mean and variability of the 6-min walk test (6MWT) clinical endpoint. An indirect response model with a latent process was fit to digitized literature data using full Bayesian estimation. The modeling data set consisted of 22 healthy controls and 218 DMD patients from one interventional and four observational trials. The model reasonably described the central tendency and population variability of the 6MWT in healthy subjects and DMD patients. An exploratory categorical covariate analysis indicated that there was no apparent effect of corticosteroid administration on DMD disease progression. The population predicted 6MWT began to rise at 1.32 years of age, plateauing at 654 meters (m) at 17.2 years of age for the healthy population. The DMD trajectory reached a maximum of 411 m at 8.90 years before declining and falling below 1 m at age 18.0. The model has potential to be used as a Bayesian estimation and posterior simulation tool to make informed model-based drug development decisions that incorporate prior knowledge with new data.
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Affiliation(s)
- Janelle L Lennie
- Metrum Research Group, Tariffville, CT, 06081, USA.
- University of Connecticut, Storrs, CT, 06268, USA.
| | | | - Marc R Gastonguay
- Metrum Research Group, Tariffville, CT, 06081, USA
- University of Connecticut, Storrs, CT, 06268, USA
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Chrzanowski SM, Darras BT, Rutkove SB. The Value of Imaging and Composition-Based Biomarkers in Duchenne Muscular Dystrophy Clinical Trials. Neurotherapeutics 2020; 17:142-152. [PMID: 31879850 PMCID: PMC7007477 DOI: 10.1007/s13311-019-00825-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
As the drug development pipeline for Duchenne muscular dystrophy (DMD) rapidly advances, clinical trial outcomes need to be optimized. Effective assessment of disease burden, natural history progression, and response to therapy in clinical trials for Duchenne muscular dystrophy are critical factors for clinical trial success. By choosing optimal biomarkers to better assess therapeutic efficacy, study costs and sample size requirements can be reduced. Currently, functional measures continue to serve as the primary outcome for the majority of DMD clinical trials. Quantitative measures of muscle health, including magnetic resonance imaging and spectroscopy, electrical impedance myography, and ultrasound, sensitively identify diseased muscle, disease progression, and response to a therapeutic intervention. Furthermore, such non-invasive techniques have the potential to identify disease pathology prior to onset of clinical symptoms. Despite robust supportive evidence, non-invasive quantitative techniques are still not frequently utilized in clinical trials for Duchenne muscular dystrophy. Non-invasive quantitative techniques have demonstrated the ability to quantify disease progression and potential response to therapeutic intervention, and should be used as a supplement to current standard functional measures. Such methods have the potential to significantly accelerate the development and approval of therapies for DMD.
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Affiliation(s)
- Stephen M Chrzanowski
- Department of Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA.
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
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Pascual Morena C, Martinez-Vizcaino V, Álvarez-Bueno C, Fernández Rodríguez R, Jiménez López E, Torres-Costoso AI, Cavero-Redondo I. Effectiveness of pharmacological treatments in Duchenne muscular dystrophy: a protocol for a systematic review and meta-analysis. BMJ Open 2019; 9:e029341. [PMID: 31494609 PMCID: PMC6731948 DOI: 10.1136/bmjopen-2019-029341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION In recent years, important advances have been made in the treatment of Duchenne muscular dystrophy (DMD). This protocol proposes a methodology for carrying out a systematic review and meta-analysis that aims to: (1) improve the evidence of the benefits of different pharmacological treatments in boys with DMD, and (2) compare the benefit of treatments specifically aimed at delaying the progression of disease in the functional outcomes. METHODS AND ANALYSIS This protocol is guided by the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and by the Cochrane Collaboration Handbook. A thorough selection of the literature will be done through the MEDLINE, EMBASE and Web of Science databases. The search will be conducted in English and Spanish. The Risk of Bias 2.0 tool from the Cochrane Collaboration will be used to assess the risk of bias. A narrative synthesis of the data will be performed. Meta-analysis will be conducted for effect of treatment on the 6 min walking distance (6MWD), North Star Ambulatory Assessment and Timed Functional Tests. Subgroup analyses will be performed by age or baseline values of the 6MWD, and overall bias. ETHICS AND DISSEMINATION The approval of an ethical committee is not required. All the included trials will comply with the current ethical standards and the Declaration of Helsinki. The results of this proposed systematic review and meta-analysis will provide a general overview and evidence concerning the effectiveness of pharmacological treatments in Duchenne muscular dystrophy. Findings will be disseminated to academic audiences through peer-reviewed publications, as well as to clinical audiences, patients' associations and policy makers, and may influence guideline developers in order to improve outcomes for these patients. PROSPERO REGISTRATION NUMBER CRD42018102207.
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Affiliation(s)
| | - Vicente Martinez-Vizcaino
- Universidad de Castilla-La Mancha, Health and Social Research Center, Cuenca, Spain
- Universidad Autónoma de Chile, Facultad de Ciencias de la Salud, Talca, Chile
| | - Celia Álvarez-Bueno
- Universidad de Castilla-La Mancha, Health and Social Research Center, Cuenca, Spain
- Universidad Politecnica y Artísitca del Paraguay, Asunción, Paraguay
| | | | - Estela Jiménez López
- Universidad de Castilla-La Mancha, Health and Social Research Center, Cuenca, Spain
- CIBERSAM (Biomedical Research Networking Centre in Mental Health), Madrid, Spain
| | | | - Iván Cavero-Redondo
- Universidad de Castilla-La Mancha, Health and Social Research Center, Cuenca, Spain
- Universidad Politecnica y Artísitca del Paraguay, Asunción, Paraguay
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Ma KM, Thomas ES, Wereszczynski J, Menhart N. Empirical and Computational Comparison of Alternative Therapeutic Exon Skip Repairs for Duchenne Muscular Dystrophy. Biochemistry 2019; 58:2061-2076. [PMID: 30896926 DOI: 10.1021/acs.biochem.9b00062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a common and devastating genetic disease primarily caused by exon deletions that create a genetic frameshift in dystrophin. Exon skipping therapy seeks to correct this by masking an exon during the mRNA maturation process, restoring dystrophin expression, but creating an edited protein missing both the original defect and the therapeutically skipped region. Crucially, it is possible to correct many defects in alternative ways, by skipping an exon either before or after the patient's defect. This results in alternatively edited, hybrid proteins that might have different properties and therapeutic consequences. We examined three such dystrophin exon-skipped edits, Δe45-53, Δe46-54, and Δe47-55, comprising two pairs of alternative repairs of Δe46-53 and Δe47-54 DMD defects. We found that in both cases, Δe46-54 was the more stable repair as determined by a variety of thermodynamic and biochemical measurements. We also examined the origin of these differences with molecular dynamics simulations, which showed that these stability differences were the result of different types of structural perturbations. For example, in one edit there was partial unfolding at the edit site that caused domain-localized perturbations while in another there was unfolding at the protein domain junctions distal to the edit site that increased molecular flexibility. These results demonstrate that alternative exon skip repairs of the same underlying defect can have very different consequences at the level of protein structure and stability and furthermore that these can arise by different mechanisms, either locally or by more subtle long-range perturbations.
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