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Roger AL, Biswas DD, Huston ML, Le D, Bailey AM, Pucci LA, Shi Y, Robinson-Hamm J, Gersbach CA, ElMallah MK. Respiratory characterization of a humanized Duchenne muscular dystrophy mouse model. Respir Physiol Neurobiol 2024; 326:104282. [PMID: 38782084 DOI: 10.1016/j.resp.2024.104282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/07/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Duchenne muscular dystrophy (DMD) is the most common X-linked disease. DMD is caused by a lack of dystrophin, a critical structural protein in striated muscle. Dystrophin deficiency leads to inflammation, fibrosis, and muscle atrophy. Boys with DMD have progressive muscle weakness within the diaphragm that results in respiratory failure in the 2nd or 3rd decade of life. The most common DMD mouse model - the mdx mouse - is not sufficient for evaluating genetic medicines that specifically target the human DMD (hDMD) gene sequence. Therefore, a novel transgenic mouse carrying the hDMD gene with an exon 52 deletion was created (hDMDΔ52;mdx). We characterized the respiratory function and pathology in this model using whole body plethysmography, histology, and immunohistochemistry. At 6-months-old, hDMDΔ52;mdx mice have reduced maximal respiration, neuromuscular junction pathology, and fibrosis throughout the diaphragm, which worsens at 12-months-old. In conclusion, the hDMDΔ52;mdx exhibits moderate respiratory pathology, and serves as a relevant animal model to study the impact of novel genetic therapies, including gene editing, on respiratory function.
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Affiliation(s)
- Angela L Roger
- Department of Pediatrics, Duke University, Durham, NC, USA
| | | | | | - Davina Le
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Aidan M Bailey
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Logan A Pucci
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Yihan Shi
- Department of Pediatrics, Duke University, Durham, NC, USA
| | | | | | - Mai K ElMallah
- Department of Pediatrics, Duke University, Durham, NC, USA.
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Maxwell MN, Marullo AL, Valverde-Pérez E, Slyne AD, Murphy BT, O'Halloran KD. Chronic N-acetyl cysteine treatment does not improve respiratory system performance in the mdx mouse model of Duchenne muscular dystrophy. Exp Physiol 2024. [PMID: 38867461 DOI: 10.1113/ep091862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024]
Abstract
Duchenne muscular dystrophy (DMD) is characterised by respiratory muscle injury, inflammation, fibrosis and weakness, ultimately culminating in respiratory failure. The dystrophin-deficient mouse model of DMD (mdx) shows evidence of respiratory muscle remodelling and dysfunction contributing to impaired respiratory system performance. The antioxidant N-acetylcysteine (NAC) has been shown to exert anti-inflammatory and anti-fibrotic effects leading to improved respiratory muscle performance in a range of animal models of muscle dysfunction, including mdx mice, following short-term administration (2 weeks). We sought to build on previous work by exploring the effects of chronic NAC administration (3 months) on respiratory system performance in mdx mice. One-month-old male mdx mice were randomised to receive normal drinking water (n = 30) or 1% NAC in the drinking water (n = 30) for 3 months. At 4 months of age, we assessed breathing in conscious mice by plethysmography followed by ex vivo assessment of diaphragm force-generating capacity. Additionally, diaphragm histology was performed. In separate studies, in anaesthetised mice, respiratory electromyogram (EMG) activity and inspiratory pressure across a range of behaviours were determined, including assessment of peak inspiratory pressure-generating capacity. NAC treatment did not affect force-generating capacity of the mdx diaphragm. Collagen content and immune cell infiltration were unchanged in mdx + NAC compared with mdx diaphragms. Additionally, there was no significant effect of NAC on breathing, ventilatory responsiveness, inspiratory EMG activity or inspiratory pressure across the range of behaviours from basal conditions to peak system performance. We conclude that chronic NAC treatment has no apparent beneficial effects on respiratory system performance in the mdx mouse model of DMD suggesting limited potential of NAC treatment alone for human DMD.
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Affiliation(s)
| | | | - Esther Valverde-Pérez
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, Valladolid, Spain
- Unidad de Excelencia Instituto Biomedicina y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Aoife D Slyne
- Department of Physiology, University College Cork, Cork, Ireland
| | - Ben T Murphy
- Department of Physiology, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, University College Cork, Cork, Ireland
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Bencze M, Periou B, Punzón I, Barthélémy I, Taglietti V, Hou C, Zaidan L, Kefi K, Blot S, Agbulut O, Gervais M, Derumeaux G, Authier F, Tiret L, Relaix F. Receptor interacting protein kinase-3 mediates both myopathy and cardiomyopathy in preclinical animal models of Duchenne muscular dystrophy. J Cachexia Sarcopenia Muscle 2023; 14:2520-2531. [PMID: 37909859 PMCID: PMC10751447 DOI: 10.1002/jcsm.13265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 03/27/2023] [Accepted: 04/24/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is a progressive muscle degenerative disorder, culminating in a complete loss of ambulation, hypertrophic cardiomyopathy and a fatal cardiorespiratory failure. Necroptosis is the form of necrosis that is dependent upon the receptor-interacting protein kinase (RIPK) 3; it is involved in several inflammatory and neurodegenerative conditions. We previously identified RIPK3 as a key player in the acute myonecrosis affecting the hindlimb muscles of the mdx dystrophic mouse model. Whether necroptosis also mediates respiratory and heart disorders in DMD is currently unknown. METHODS Evidence of activation of the necroptotic axis was examined in dystrophic tissues from Golden retriever muscular dystrophy (GRMD) dogs and R-DMDdel52 rats. A functional assessment of the involvement of necroptosis in dystrophic animals was performed on mdx mice that were genetically depleted for RIPK3. Dystrophic mice aged from 12 to 18 months were analysed by histology and molecular biology to compare the phenotype of muscles from mdxRipk3+/+ and mdxRipk3-/- mice. Heart function was also examined by echocardiography in 40-week-old mice. RESULTS RIPK3 expression in sartorius and biceps femoris muscles from GRMD dogs positively correlated to myonecrosis levels (r = 0.81; P = 0.0076). RIPK3 was also found elevated in the diaphragm (P ≤ 0.05). In the slow-progressing heart phenotype of GRMD dogs, the phosphorylated form of RIPK1 at the Serine 161 site was dramatically increased in cardiomyocytes. A similar p-RIPK1 upregulation characterized the cardiomyocytes of the severe DMDdel52 rat model, associated with a marked overexpression of Ripk1 (P = 0.007) and Ripk3 (P = 0.008), indicating primed activation of the necroptotic pathway in the dystrophic heart. MdxRipk3-/- mice displayed decreased compensatory hypertrophy of the heart (P = 0.014), and echocardiography showed a 19% increase in the relative wall thickness (P < 0.05) and 29% reduction in the left ventricle mass (P = 0.0144). Besides, mdxRipk3-/- mice presented no evidence of a regenerative default or sarcopenia in skeletal muscles, moreover around 50% less affected by fibrosis (P < 0.05). CONCLUSIONS Our data highlight molecular and histological evidence that the necroptotic pathway is activated in degenerative tissues from dystrophic animal models, including the diaphragm and the heart. We also provide the genetic proof of concept that selective inhibition of necroptosis in dystrophic condition improves both histological features of muscles and cardiac function, suggesting that prevention of necroptosis is susceptible to providing multiorgan beneficial effects for DMD.
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Affiliation(s)
- Maximilien Bencze
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Baptiste Periou
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Isabel Punzón
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Inès Barthélémy
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Valentina Taglietti
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Cyrielle Hou
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Louai Zaidan
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Kaouthar Kefi
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Stéphane Blot
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Onnik Agbulut
- Institut de Biologie Paris‐Seine (IBPS), CNRS UMR 8256, Inserm ERL U1164, Biological Adaptation and AgeingSorbonne UniversitéParisFrance
| | - Marianne Gervais
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Geneviève Derumeaux
- Team Derumeaux, Department of Physiology, Henri Mondor Hospital, FHU‐SENEC, AP‐HPU955‐IMRB, Université Paris‐Est Créteil (UPEC)CréteilFrance
| | - François‐Jérôme Authier
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Laurent Tiret
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
| | - Fréderic Relaix
- Team Relaix, Biology of the Neuromuscular SystemU955‐IMRB, Inserm, UPEC, ENVA, EFSCréteilFrance
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O'Halloran KD, Maxwell MN, Marullo AL, Hamilton CP, Ó Murchú SC, Burns DP, Mahony CM, Slyne AD, Drummond SE. Loss of compensation afforded by accessory muscles of breathing leads to respiratory system compromise in the mdx mouse model of Duchenne muscular dystrophy. J Physiol 2023; 601:4441-4467. [PMID: 37688347 DOI: 10.1113/jp285203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Despite profound diaphragm weakness, peak inspiratory pressure-generating capacity is preserved in young mdx mice revealing adequate compensation by extra-diaphragmatic muscles of breathing in early dystrophic disease. We hypothesised that loss of compensation gives rise to respiratory system compromise in advanced dystrophic disease. Studies were performed in male wild-type (n = 196) and dystrophin-deficient mdx mice (n = 188) at 1, 4, 8, 12 and 16 months of age. In anaesthetised mice, inspiratory pressure and obligatory and accessory respiratory EMG activities were recorded during baseline and sustained tracheal occlusion for up to 30-40 s to evoke peak system activation to task failure. Obligatory inspiratory EMG activities were lower in mdx mice across the ventilatory range to peak activity, emerging in early dystrophic disease. Early compensation protecting peak inspiratory pressure-generating capacity in mdx mice, which appears to relate to transforming growth factor-β1-dependent fibrotic remodelling of the diaphragm and preserved accessory muscle function, was lost at 12 and 16 months of age. Denervation and surgical lesion of muscles of breathing in 4-month-old mice revealed a greater dependency on diaphragm for peak inspiratory performance in wild-type mice, whereas mdx mice were heavily dependent upon accessory muscles (including abdominal muscles) for peak performance. Accessory EMG activities were generally preserved or enhanced in young mdx mice, but peak EMG activities were lower than wild-type by 12 months of age. In general, ventilation was reasonably well protected in mdx mice until 16 months of age. Despite the early emergence of impairments in the principal obligatory muscles of breathing, peak inspiratory performance is compensated in early dystrophic disease due to diaphragm remodelling and facilitated contribution by accessory muscles of breathing. Loss of compensation afforded by accessory muscles underpins the emergence of respiratory system morbidity in advanced dystrophic disease. KEY POINTS: Despite diaphragm weakness, peak inspiratory performance is preserved in young dystrophin-deficient mdx mice revealing adequate compensation by extra-diaphragmatic muscles. Peak obligatory muscle (diaphragm, external intercostal, and parasternal intercostal) EMG activities are lower in mdx mice, emerging early in dystrophic disease, before the temporal decline in peak performance. Peak EMG activities of some accessory muscles are lower, whereas others are preserved. There is greater recruitment of the trapezius muscle in mdx mice during peak system activation. In phrenicotomised mice with confirmed diaphragm paralysis, there is a greater contribution made by extra-diaphragmatic muscles to peak inspiratory pressure in mdx compared with wild-type mice. Surgical lesion of accessory (including abdominal) muscles adversely affects peak pressure generation in mdx mice. Diaphragm remodelling leading to stiffening provides a mechanical advantage to peak pressure generation via the facilitated action of extra-diaphragmatic muscles in early dystrophic disease. Peak accessory EMG activities are lower in 12-month-old mdx compared to wild-type mice. Peak inspiratory pressure declines in mdx mice with advanced disease. We conclude that compensation afforded by accessory muscles of breathing declines in advanced dystrophic disease precipitating the emergence of respiratory system dysfunction.
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Affiliation(s)
- Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Michael N Maxwell
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Anthony L Marullo
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Chantelle P Hamilton
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Seán C Ó Murchú
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Conor M Mahony
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Aoife D Slyne
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Sarah E Drummond
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
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Sheers NL, O’Sullivan R, Howard ME, Berlowitz DJ. The role of lung volume recruitment therapy in neuromuscular disease: a narrative review. FRONTIERS IN REHABILITATION SCIENCES 2023; 4:1164628. [PMID: 37565183 PMCID: PMC10410160 DOI: 10.3389/fresc.2023.1164628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/16/2023] [Indexed: 08/12/2023]
Abstract
Respiratory muscle weakness results in substantial discomfort, disability, and ultimately death in many neuromuscular diseases. Respiratory system impairment manifests as shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing, and chronic ventilatory failure. Ventilatory support (i.e., non-invasive ventilation) is an established and key treatment for the latter. As survival outcomes improve for people living with many neuromuscular diseases, there is a shift towards more proactive and preventative chronic disease multidisciplinary care models that aim to manage symptoms, improve morbidity, and reduce mortality. Clinical care guidelines typically recommend therapies to improve cough effectiveness and mobilise mucus, with the aim of averting acute respiratory compromise or respiratory tract infections. Moreover, preventing recurrent infective episodes may prevent secondary parenchymal pathology and further lung function decline. Regular use of techniques that augment lung volume has similarly been recommended (volume recruitment). It has been speculated that enhancing lung inflation in people with respiratory muscle weakness when well may improve respiratory system "flexibility", mitigate restrictive chest wall disease, and slow lung volume decline. Unfortunately, clinical care guidelines are based largely on clinical rationale and consensus opinion rather than level A evidence. This narrative review outlines the physiological changes that occur in people with neuromuscular disease and how these changes impact on breathing, cough, and respiratory tract infections. The biological rationale for lung volume recruitment is provided, and the clinical trials that examine the immediate, short-term, and longer-term outcomes of lung volume recruitment in paediatric and adult neuromuscular diseases are presented and the results synthesised.
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Affiliation(s)
- Nicole L. Sheers
- Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, VIC, Australia
- Institute for Breathing and Sleep, Heidelberg, VIC, Australia
- Department of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Rachel O’Sullivan
- Department of Physiotherapy, Christchurch Hospital, Canterbury, New Zealand
| | - Mark E. Howard
- Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, VIC, Australia
- Institute for Breathing and Sleep, Heidelberg, VIC, Australia
- Department of Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Turner Institute of Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - David J. Berlowitz
- Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, VIC, Australia
- Institute for Breathing and Sleep, Heidelberg, VIC, Australia
- Department of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Department of Physiotherapy, Austin Health, Heidelberg, VIC, Australia
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Sobierajska-Rek A, Wasilewska E, Śledzińska K, Jabłońska-Brudło J, Małgorzewicz S, Wasilewski A, Szalewska D. The Association between the Respiratory System and Upper Limb Strength in Males with Duchenne Muscular Dystrophy: A New Field for Intervention? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:15675. [PMID: 36497753 PMCID: PMC9736927 DOI: 10.3390/ijerph192315675] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
UNLABELLED Progressive, irreversible muscle weakness is the leading symptom of Duchenne muscular dystrophy (DMD), often resulting in death from respiratory muscle failure. Little is known about the relationship between the functioning of the respiratory system and the hand grip-a function which remains long preserved. This study aimed to investigate the interdependence between muscle strength and the function of both hand grip and the respiratory system in patients with DMD. MATERIALS AND METHOD The study included cohort patients, aged 6-17, with DMD, recruited from the Rare Disease Centre, Gdansk, Poland. Clinical status (Vignos scale, Brook scale), pulmonary function (respiratory muscle strength-MIP, MEP); spirometry (FEV1; FVC), as well as upper limb function (performance of the upper limb-PUL 2.0) and hand grip strength (HGS) (hand-held dynamometer) were evaluated in all participants. RESULTS Finally, 53 boys (mean age 11.41 ± 3.70 years, 25 non-ambulant) were included. Each of the participants presented a lower %pv of MIP (48.11 ± 27), MEP (38.11 ± 22), PUL (75.64 ± 27), and HGS (33.28 ± 18). There were differences between the ambulatory and non-ambulatory groups in values of MIP, MEP, FVC, PUL, HGS (p < 0.001 for all), and FEV1 (p < 0.013). There were correlations between PUL, HGS, and MIP (R = 0.56; R = 0.61, p < 0.001 both), MEP (R = 0.59; R = 0.62, p < 0.001), FVC (R = 0.77; R = 0.77, p < 0.001), and FEV1 (R = 0.77; R = 0.79; p < 0.001). These correlations were found for all participants, but non-ambulatory patients presented stronger relationships. CONCLUSIONS 1. The pulmonary and upper limb functions were within the normal range in ambulatory and low in non-ambulatory patients with DMD, but the muscle strength of both systems was low, regardless of the stage of the disease. 2. There seems to be an interdependence between the respiratory system and upper limb strength in terms of muscle strength and function in DMD patients, which is stronger in non-ambulatory patients. This may be the basis for the creation of a new personalized plan in rehabilitation-the simultaneous rehabilitation of the respiratory and upper limb muscles. Further studies on this theory should be conducted.
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Affiliation(s)
- Agnieszka Sobierajska-Rek
- Department of Rehabilitation Medicine, Faculty of Health Sciences with the Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-219 Gdańsk, Poland
| | - Eliza Wasilewska
- Department of Pulmonology and Allergology, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdańsk, Poland
| | - Karolina Śledzińska
- Department of Internal and Pediatric Nursing, Faculty of Health Sciences with the Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-211 Gdańsk, Poland
| | - Joanna Jabłońska-Brudło
- Department of Rehabilitation Medicine, Faculty of Health Sciences with the Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-219 Gdańsk, Poland
| | - Sylwia Małgorzewicz
- Department of Clinical Nutrition, Faculty of Health Sciences with the Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-416 Gdańsk, Poland
| | - Andrzej Wasilewski
- Student Scientific Association at Department of Physical Education and Sport, Wroclaw Medical University, 51-601 Wroclaw, Poland
| | - Dominika Szalewska
- Department of Rehabilitation Medicine, Faculty of Health Sciences with the Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-219 Gdańsk, Poland
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Mhandire DZ, Burns DP, Roger AL, O'Halloran KD, ElMallah MK. Breathing in Duchenne muscular dystrophy: Translation to therapy. J Physiol 2022; 600:3465-3482. [PMID: 35620971 PMCID: PMC9357048 DOI: 10.1113/jp281671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/17/2022] [Indexed: 11/08/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease caused by a deficiency in dystrophin - a structural protein which stabilizes muscle during contraction. Dystrophin deficiency adversely affects the respiratory system leading to sleep-disordered breathing, hypoventilation, and weakness of the expiratory and inspiratory musculature, which culminate in severe respiratory dysfunction. Muscle degeneration associated respiratory impairment in neuromuscular disease is a result of disruptions at multiple sites of the respiratory control network, including sensory and motor pathways. As a result of this pathology, respiratory failure is a leading cause of premature death in DMD patients. Currently available treatments for DMD respiratory insufficiency attenuate respiratory symptoms without completely reversing the underlying pathophysiology. This underscores the need to develop curative therapies to improve quality of life and longevity of DMD patients. This review summarises research findings on the pathophysiology of respiratory insufficiencies in DMD disease in humans and animal models, the clinical interventions available to ameliorate symptoms, and gene-based therapeutic strategies uncovered by preclinical animal studies. Abstract figure legend: Summary of the therapeutic strategies for respiratory insufficiency in DMD (Duchenne muscular dystrophy). Treatment options currently in clinical use only attenuate respiratory symptoms without reversing the underlying pathology of DMD-associated respiratory insufficiencies. Ongoing preclinical and clinical research is aimed at developing curative therapies that both improve quality of life and longevity of DMD patients. AAV - adeno-associated virus, PPMO - Peptide-conjugated phosphorodiamidate morpholino oligomer This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Doreen Z Mhandire
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Angela L Roger
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Mai K ElMallah
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
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Sahani R, Wallace CH, Jones BK, Blemker SS. Diaphragm muscle fibrosis involves changes in collagen organization with mechanical implications in Duchenne muscular dystrophy. J Appl Physiol (1985) 2022; 132:653-672. [PMID: 35050792 PMCID: PMC9076426 DOI: 10.1152/japplphysiol.00248.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In Duchenne muscular dystrophy (DMD), diaphragm muscle dysfunction results in respiratory insufficiency, a leading cause of death in patients. Increased muscle stiffness occurs with buildup of fibrotic tissue, characterized by excessive accumulation of extracellular matrix (ECM) components such as collagen, and prevents the diaphragm from achieving the excursion lengths required for respiration. However, changes in mechanical properties are not explained by collagen amount alone and we must consider the complex structure and mechanics of fibrotic tissue. The goals of our study were to 1) determine if and how collagen organization changes with the progression of DMD in diaphragm muscle tissue and 2) predict how collagen organization influences the mechanical properties of the ECM. We first visualized collagen structure with scanning electron microscopy (SEM) images and then developed an analysis framework to quantify collagen organization and generate image-based finite-element models. Image analysis revealed increased collagen fiber straightness and alignment in mdx over wild type (WT) at 3 mo (straightness: mdx = 0.976 ± 0.0108, WT = 0.887 ± 0.0309, alignment: mdx = 0.876 ± 0.0333, WT = 0.759 ± 0.0416) and 6 mo (straightness: mdx = 0.942 ± 0.0182, WT = 0.881 ± 0.0163, alignment: mdx = 0.840 ± 0.0315, WT = 0.759 ± 0.0368). Collagen fibers retained a transverse orientation relative to muscle fibers (70°-90°) in all groups. Mechanical models predicted an increase in the transverse relative to longitudinal (muscle fiber direction) stiffness, with stiffness ratio (transverse/longitudinal) increased in mdx over WT at 3 mo (mdx = 5.45 ± 2.04, WT = 1.97 ± 0.670) and 6 mo (mdx = 4.05 ± 0.985, WT = 1.96 ± 0.506). This study revealed changes in diaphragm ECM structure and mechanics during disease progression in the mdx muscular dystrophy mouse phenotype, highlighting the need to consider the role of collagen organization on diaphragm muscle function.NEW & NOTEWORTHY Scanning electron microscopy images of decellularized diaphragm muscle from WT and mdx, Duchenne muscular dystrophy model, mice revealed that collagen fibers in the epimysium are oriented transverse to muscle fibers, with age- and disease-dependent changes in collagen arrangement. Finite-element models generated from these images predicted that changes in collagen arrangement during disease progression influence the mechanical properties of the extracellular matrix. Thus, changes in collagen fiber-level structure are implicated on tissue-level properties during fibrosis.
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Affiliation(s)
- Ridhi Sahani
- 1Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - C. Hunter Wallace
- 1Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Brian K. Jones
- 1Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Silvia S. Blemker
- 1Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia,2Department of Orthopedic Surgery, University of Virginia, Charlottesville, Virginia,3Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia
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Servais L, Mercuri E, Straub V, Guglieri M, Seferian AM, Scoto M, Leone D, Koenig E, Khan N, Dugar A, Wang X, Han B, Wang D, Muntoni F. Long-Term Safety and Efficacy Data of Golodirsen in Ambulatory Patients with Duchenne Muscular Dystrophy Amenable to Exon 53 Skipping: A First-in-human, Multicenter, Two-Part, Open-Label, Phase 1/2 Trial. Nucleic Acid Ther 2021; 32:29-39. [PMID: 34788571 PMCID: PMC8817703 DOI: 10.1089/nat.2021.0043] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The aim of this Phase 1/2, 2-part, multicenter trial was to report clinical safety and efficacy of long-term golodirsen treatment among ambulatory patients with exon 53 skip-amenable Duchenne muscular dystrophy (DMD). Part 1 was a 12-week, randomized, double-blind, placebo-controlled, dose-titration study followed by 9-week safety review. Part 2 was a 168-week, open-label evaluation of golodirsen 30 mg/kg. Part 1 primary endpoint was safety. Part 2 primary endpoints were dystrophin protein expression and 6-minute walk test (6MWT); secondary endpoints were percent predicted forced vital capacity (FVC%p) and safety. Post hoc ambulation analyses used mutation-matched external natural history controls. All patients from Part 1 (golodirsen, n = 8; placebo, n = 4) plus 13 additional patients entered Part 2; 23 completed the study. Adverse events were generally mild, nonserious, and unrelated to golodirsen, with no safety-related discontinuations or deaths. Golodirsen increased dystrophin protein (16.0-fold; P < 0.001) and exon skipping (28.9-fold; P < 0.001). At 3 years, 6MWT change from baseline was −99.0 m for golodirsen-treated patients versus −181.4 m for external controls (P = 0.067), and loss of ambulation occurred in 9% versus 26% (P = 0.21). FVC%p declined 8.4% over 3 years in golodirsen-treated patients, comparing favorably with literature-reported rates. This study provides evidence for golodirsen biologic activity and long-term safety in a declining DMD population and suggests functional benefit versus external controls. Clinical Trial Registration number: NCT02310906.
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Affiliation(s)
- Laurent Servais
- I-Motion Institute, Hôpital Armand Trousseau, Paris, France.,Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Liège, Belgium.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, United Kingdom
| | - Eugenio Mercuri
- Pediatric Neurology Unit, Università Cattolica del Sacro Cuore Roma, Rome, Italy.,Nemo Clinical Centre, Fondazione Policlinico Universitario A Gemelli IRCCS, Rome, Italy
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Michela Guglieri
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | | | - Mariacristina Scoto
- Dubowitz Neuromuscular Centre, University College London, Great Ormond Street Institute of Child Health, London, United Kingdom.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
| | - Daniela Leone
- Nemo Clinical Centre, Fondazione Policlinico Universitario A Gemelli IRCCS, Rome, Italy
| | - Erica Koenig
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Navid Khan
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Ashish Dugar
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Xiaodong Wang
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Baoguang Han
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Dan Wang
- Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, University College London, Great Ormond Street Institute of Child Health, London, United Kingdom.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
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10
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Pennati F, LoMauro A, D’Angelo MG, Aliverti A. Non-Invasive Respiratory Assessment in Duchenne Muscular Dystrophy: From Clinical Research to Outcome Measures. Life (Basel) 2021; 11:life11090947. [PMID: 34575096 PMCID: PMC8468718 DOI: 10.3390/life11090947] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/06/2021] [Accepted: 09/06/2021] [Indexed: 12/03/2022] Open
Abstract
Ventilatory failure, due to the progressive wasting of respiratory muscles, is the main cause of death in patients with Duchenne muscular dystrophy (DMD). Reliable measures of lung function and respiratory muscle action are important to monitor disease progression, to identify early signs of ventilatory insufficiency and to plan individual respiratory management. Moreover, the current development of novel gene-modifying and pharmacological therapies highlighted the urgent need of respiratory outcomes to quantify the effects of these therapies. Pulmonary function tests represent the standard of care for lung function evaluation in DMD, but provide a global evaluation of respiratory involvement, which results from the interaction between different respiratory muscles. Currently, research studies have focused on finding novel outcome measures able to describe the behavior of individual respiratory muscles. This review overviews the measures currently identified in clinical research to follow the progressive respiratory decline in patients with DMD, from a global assessment to an individual structure–function muscle characterization. We aim to discuss their strengths and limitations, in relation to their current development and suitability as outcome measures for use in a clinical setting and as in upcoming drug trials in DMD.
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Affiliation(s)
- Francesca Pennati
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy; (A.L.); (A.A.)
- Correspondence:
| | - Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy; (A.L.); (A.A.)
| | | | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy; (A.L.); (A.A.)
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11
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Fayssoil A, Chaffaut C, Prigent H, Laforet P, Clair B, Orlikowski D, Ogna A, Chevret S, Meng P, Annane D, Lofaso F, Crenn P. Nutritional status, swallowing disorders, and respiratory prognosis in adult Duchenne muscular dystrophy patients. Pediatr Pulmonol 2021; 56:2146-2154. [PMID: 33939888 DOI: 10.1002/ppul.25430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 03/16/2021] [Accepted: 04/12/2021] [Indexed: 11/08/2022]
Abstract
Malnutrition and swallowing disorders are common in Duchenne muscular dystrophy (DMD) patients. We assessed, in adult DMD with home mechanical ventilation (HMV) and cough assist device, its prevalence and the relationships with respiratory muscle strength and long-term respiratory prognosis. We reviewed the patients (n = 117, age 18-39 years [median 24]), followed in a reference center, from 2006 to 2015, to obtain clinical baseline, nutritional status, vital capacity (VC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). The median body mass index (BMI) was low (15.6 kg/m²). Included patients had severe restrictive respiratory function with a median VC of 10.5% [7-17] of the predicted value. All patients were on HMV. Prevalence of malnutrition, swallowing disorders, and gastrostomy were respectively 62%, 34%, and 11%. BMI and serum albumin level were significantly associated with MIP, MEP, and VC. The 1-year/5-years cumulative incidences of respiratory events (pulmonary sepsis and acute respiratory distress) were, respectively, 20.7%/44.5%. Using univariate analysis, predictive factors for respiratory events were swallowing disorders (p = .001), transthyretinemia (p = .034), MIP (p = .039), and MEP (p = .03) but not BMI or albuminemia. Using multivariate analysis, only swallowing disorders remained significantly associated with respiratory events (OR = 4.2, IC 95% 1.31-12.2, p = .01). In conclusion, this study highlights the interrelationships between nutritional intake, swallowing function, airway clearance, and respiratory function in adult DMD. A multidisciplinary approach focusing on these previous factors is essential to optimize DMD patient health.
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Affiliation(s)
- Abdallah Fayssoil
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Service de cardiologie, Centre de référence des cardiomyopathies et des troubles du rythme cardiaque héréditaires ou rares, Hôpital Ambroise Paré, AP-HP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Boulogne-Billancourt, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Cendrine Chaffaut
- Service de Biostatistiques et Information Médicale (SBIM), Hôpital Saint Louis, APHP, Université Paris, Paris, France
| | - Helene Prigent
- CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Service de Physiologie-Explorations fonctionnelles, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Pascal Laforet
- CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Service de Neurologie/Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Bernard Clair
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - David Orlikowski
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Adam Ogna
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Sylvie Chevret
- Service de Biostatistiques et Information Médicale (SBIM), Hôpital Saint Louis, APHP, Université Paris, Paris, France
| | - Paris Meng
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Djillali Annane
- Service de Médecine intensive et Réanimation/Unité de ventilation à domicile, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Frederic Lofaso
- CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Service de Physiologie-Explorations fonctionnelles, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Pascal Crenn
- CRMR des maladies neuromusculaires Nord-Est-Ile de France, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique (CIC) 1429 INSERM, Hôpital Raymond Poincaré, APHP, Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France.,Unité de Nutrition clinique transversale, Hôpital Raymond Poincaré, APHP Université Paris Saclay/UFR Simone Veil-Santé-Université de Versailles Saint Quentin en Yvelines, Garches, France
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12
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van Doorn JLM, Pennati F, Hansen HHG, van Engelen BGM, Aliverti A, Doorduin J. Respiratory muscle imaging by ultrasound and MRI in neuromuscular disorders. Eur Respir J 2021; 58:13993003.00137-2021. [PMID: 33863737 DOI: 10.1183/13993003.00137-2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/26/2021] [Indexed: 11/05/2022]
Abstract
Respiratory muscle weakness is common in neuromuscular disorders and leads to significant respiratory difficulties. Therefore, reliable and easy assessment of respiratory muscle structure and function in neuromuscular disorders is crucial. In the last decade, ultrasound and MRI emerged as promising imaging techniques to assess respiratory muscle structure and function. Respiratory muscle imaging directly measures the respiratory muscles and, in contrast to pulmonary function testing, is independent of patient effort. This makes respiratory muscle imaging suitable to use as tool in clinical respiratory management and as outcome parameter in upcoming drug trials for neuromuscular disorders, particularly in children. In this narrative review, we discuss the latest studies and technological developments in imaging of the respiratory muscles by US and MR, and its clinical application and limitations. We aim to increase understanding of respiratory muscle imaging and facilitate its use as outcome measure in daily practice and clinical trials.
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Affiliation(s)
- Jeroen L M van Doorn
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Francesca Pennati
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Hendrik H G Hansen
- Department of Medical Imaging, Medical Ultrasound Imaging Center (MUSIC), Radboud University Medical Center, Nijmegen, the Netherlands
| | - Baziel G M van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Jonne Doorduin
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
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13
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Miller K, Mayer OH. Pulmonary function testing in patients with neuromuscular disease. Pediatr Pulmonol 2021; 56:693-699. [PMID: 33290643 DOI: 10.1002/ppul.25182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 11/11/2022]
Abstract
Progressive neuromuscular disease leads to muscle weakness or failure that produces loss of pulmonary function and clinical respiratory morbidity. Tracking pulmonary function in a practical and effective way is very important because it can help identify a stage of disease when a morbidity, such as inadequate airway clearance or respiratory failure, may be present. There are four general categories of pulmonary function outcome measures such as volume, flow, pressure, and gas exchange. These outcome measures have variable precision and accuracy in predicting clinical change, and practicality in performing them relative to age and condition. It is widely recommended to follow multiple measurements longitudinally and create an accurate and timely clinical picture. This manuscript will review the most commonly used and most practical measures for use in clinical practice and how they can help to assess morbidity, disease state, and help optimize patient management.
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Affiliation(s)
- Kristen Miller
- Division of Pulmonology, The Children's Hospital of Philadelphia, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Oscar H Mayer
- Division of Pulmonology, The Children's Hospital of Philadelphia, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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14
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De Wel B, Willaert S, Nadaj-Pakleza A, Aubé-Nathier AC, Testelmans D, Buyse B, Claeys KG. Respiratory decline in adult patients with Becker muscular dystrophy: A longitudinal study. Neuromuscul Disord 2021; 31:174-182. [PMID: 33454189 DOI: 10.1016/j.nmd.2020.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/13/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
Becker muscular dystrophy (BMD) is a rare hereditary neuromuscular disease, caused by a genetic defect in the Duchenne Muscular Dystrophy (DMD) gene. We studied the natural history of respiratory function and its affecting factors in 23 adult BMD patients. These important data are needed for (future) clinical trials in BMD but are largely lacking. Patients had a median age of 51 years (28-78y) and median follow-up duration of 14 years (2-25y). We analysed 190 pulmonary function measurements with a median interval of one year (1-17y) and measured a 1.00% decline of Forced Vital Capacity percent predicted (FVC%pred) per year (p = 0.004). Loss of ambulation significantly increased the annual rate of FVC decline and was dependent of patient's body mass index (BMI; p = 0.015), with increases in BMI correlating with an even more rapid deterioration of FVC. A decline in Medical Research Council (MRC) sum score was significantly correlated with a decline in FVC (p = 0.003). We conclude that adult BMD patients experience a significant but mild respiratory decline. However, this decline is significantly more rapid and clinically relevant after loss of ambulation, which warrants a more vigilant follow-up of respiratory function in this subgroup.
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Affiliation(s)
- Bram De Wel
- Department of Neurology, Neuromuscular Reference Centre, University Hospitals Leuven, Leuven, Belgium; Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | | | - Aleksandra Nadaj-Pakleza
- Department of Neurology, Neuromuscular Reference Centre Nord/Est/IdF, CHU Strasbourg, Strasbourg, France
| | | | - Dries Testelmans
- Department of Pulmonology, Leuven University Centre for Sleep and Wake Disorders, University Hospitals Leuven, Leuven, Belgium
| | - Bertien Buyse
- Department of Pulmonology, Leuven University Centre for Sleep and Wake Disorders, University Hospitals Leuven, Leuven, Belgium
| | - Kristl G Claeys
- Department of Neurology, Neuromuscular Reference Centre, University Hospitals Leuven, Leuven, Belgium; Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, and Leuven Brain Institute, KU Leuven, Leuven, Belgium.
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15
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Fauroux B, Griffon L, Amaddeo A, Stremler N, Mazenq J, Khirani S, Baravalle-Einaudi M. Respiratory management of children with spinal muscular atrophy (SMA). Arch Pediatr 2020; 27:7S29-7S34. [PMID: 33357594 DOI: 10.1016/s0929-693x(20)30274-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Spinal muscular atrophy (SMA) causes a predominantly bilateral proximal muscle weakness and atrophy. The respiratory muscles are also involved with a weakness of the intercostal muscles and a relatively spared diaphragm. This respiratory muscle weakness translates into a cough impairment, resulting in poor clearance of airway secretions and recurrent pulmonary infections, restrictive lung disease due to a poor or insufficient chest wall and lung growth, nocturnal hypoventilation and, finally, respiratory failure. Systematic and regular monitoring of respiratory muscle performance is necessary in children with SMA in order to anticipate respiratory complications, such as acute and chronic respiratory failure, and guide clinical care. This monitoring is based in clinical practice on volitional and noninvasive tests, such as vital capacity, sniff nasal inspiratory pressure, maximal static pressures, peak expiratory flow and peak cough flow because of their simplicity, availability and ease. In young children, those with poor cooperation or severe respiratory muscle weakness, other, mostly invasive, tests may be required to evaluate respiratory muscle performance. A sleep study, or at least overnight monitoring of nocturnal gas exchange is mandatory for detecting nocturnal alveolar hypoventilation. Training for patients and caregivers in cough-assisted techniques is recommended when respiratory muscle strength falls below 50% of predicted or in case of recurrent or severe respiratory infections. Noninvasive ventilation (NIV) should be initiated in case of isolated nocturnal hypoventilation and followed by a pediatric respiratory team with expertise in NIV. Multidisciplinary (neurology and respiratory) pediatric management is crucial for optimal care of children with SMA. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
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Affiliation(s)
- B Fauroux
- Pediatric noninvasive ventilation and sleep unit, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France; Université de Paris, VIFASOM, F-75004, Paris, France.
| | - L Griffon
- Pediatric noninvasive ventilation and sleep unit, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France; Université de Paris, VIFASOM, F-75004, Paris, France
| | - A Amaddeo
- Pediatric noninvasive ventilation and sleep unit, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France; Université de Paris, VIFASOM, F-75004, Paris, France
| | - N Stremler
- Pediatric Ventilation Unit, Pediatric department, Timone-Enfants Hospital, 13385 Marseille AP-HM, Marseille, France
| | - J Mazenq
- Pediatric Ventilation Unit, Pediatric department, Timone-Enfants Hospital, 13385 Marseille AP-HM, Marseille, France
| | - S Khirani
- Pediatric noninvasive ventilation and sleep unit, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France; Université de Paris, VIFASOM, F-75004, Paris, France; ASV Sante, Gennevilliers, France
| | - M Baravalle-Einaudi
- Pediatric Ventilation Unit, Pediatric department, Timone-Enfants Hospital, 13385 Marseille AP-HM, Marseille, France
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16
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Rodríguez-Núñez I, Torres G, Luarte-Martinez S, Manterola C, Zenteno D. RESPIRATORY MUSCLE IMPAIRMENT EVALUATED WITH MEP/MIP RATIO IN CHILDREN AND ADOLESCENTS WITH CHRONIC RESPIRATORY DISEASE. ACTA ACUST UNITED AC 2020; 39:e2019414. [PMID: 33331560 PMCID: PMC7747779 DOI: 10.1590/1984-0462/2021/39/2019414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/23/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To evaluate the strength of respiratory muscles and to compare maximum inspiratory (MIP) and expiratory (MEP) pressure and MEP/MIP ratio between patients with chronic respiratory diseases and healthy individuals. METHODS Case-control study. Individuals with neuromuscular disease and post-infectious bronchiolitis obliterans were considered. In addition, they were also matched according to anthropometric and demographic characteristics with healthy children and adolescents. MIP, MEP in the three groups, and pulmonary function only in patients with chronic respiratory diseases were recorded. RESULTS A total of 52 subjects with CRD (25 with neuromuscular disease, and 27 with post-infectious bronchiolitis obliterans) and 85 healthy individuals were included, with an average age of 11.3±2.1 years. Patients with neuromuscular disease and post-infectious bronchiolitis obliterans presented lower MIP and MEP when compared with healthy individuals, although MEP/MIP ratio was lower in patients with neuromuscular disease (0.87±0.3) and higher in patients with post-infectious bronchiolitis obliterans (1.1±0.3) compared to the healthy group (0.97±0.2). Only in patients with neuromuscular disease a negative correlation was observed between MEP/MIP ratio and age (r=-0.50; p=0.01). CONCLUSIONS Differences in the pattern of muscular weakness between patients with chronic respiratory diseases were observed. In patients with neuromuscular disease, a decrease in the MEP/MIP ratio depending on MIP was verified; and in those patients with post-infectious bronchiolitis obliterans, an increase in the MEP/MIP ratio depending on MIP was also observed.
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Affiliation(s)
| | - Gerardo Torres
- Dr. Guillermo Grant Benavente Hospital, Concepción, Chile
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17
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Neuhaus SB, Wallgren-Pettersson C, Bönnemann CG, Schara U, Servais L. 250th ENMC International Workshop: Clinical trial readiness in nemaline myopathy 6-8 September 2019, Hoofdorp, the Netherlands. Neuromuscul Disord 2020; 30:866-875. [PMID: 32919842 DOI: 10.1016/j.nmd.2020.08.356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Sarah B Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, U.S.A
| | - Carina Wallgren-Pettersson
- The Folkhälsan Institute of Genetics and the Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, U.S.A
| | - Ulrike Schara
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders in Children and Adolecents, University Hospital Essen, University of Duisburg-Essen, Germany
| | - Laurent Servais
- Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Liège, Belgium; MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, United Kingdom.
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18
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Peczkowski KK, Rastogi N, Lowe J, Floyd KT, Schultz EJ, Karaze T, Davis JP, Rafael-Fortney JA, Janssen PML. Muscle Twitch Kinetics Are Dependent on Muscle Group, Disease State, and Age in Duchenne Muscular Dystrophy Mouse Models. Front Physiol 2020; 11:568909. [PMID: 33101056 PMCID: PMC7545010 DOI: 10.3389/fphys.2020.568909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/28/2020] [Indexed: 11/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by the lack of functional dystrophin protein. In muscular dystrophy preclinical research, it is pertinent to analyze the force of the muscles affected by the disease to assess pathology and potential effectiveness of therapeutic interventions. Although muscles function at sub-maximal levels in vivo, maximal tetanic contractions are most commonly used to assess and report muscle function in muscular dystrophy studies. At submaximal activation, the kinetics of contraction and relaxation are heavily impacted by the kinetics of the single twitch. However, maximal tetanic force is often the main, if not sole, outcome measured in most studies, while contractile kinetics are rarely reported. To investigate the effect of muscle disease on twitch contraction kinetics, isolated diaphragm and extensor digitorum longus (EDL) muscles of 10-, 20-week, “het” (dystrophin deficient and utrophin haplo-insufficient), and 52-week mdx (dystrophin deficient) mice were analyzed and compared to wild-type controls. We observed that twitch contractile kinetics are dependent on muscle type, age, and disease state. Specific findings include that diaphragm from wildtype mice has a greater time to 50% relaxation (RT50) than time to peak tension (TTP) compared to the het and mdx dystrophic models, where there is a similar TTP compared to RT50. Diaphragm twitch kinetics remain virtually unchanged with age, while the EDL from het and mdx mice initially has a greater RT50 than TTP, but the TTP increases with age. The difference between EDL contractile kinetics of dystrophic and wildtype mice is more prominent at young age. Differences in kinetics yielded greater statistical significance compared to previously published force measurements, thus, using kinetics as an outcome parameter could potentially allow for use of smaller experimental groups in future study designs. Although this study focused on DMD models, our findings may be applicable to other skeletal muscle conditions and diseases.
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Affiliation(s)
- Kyra K Peczkowski
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Neha Rastogi
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Jeovanna Lowe
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kyle T Floyd
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Eric J Schultz
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Tallib Karaze
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Jill A Rafael-Fortney
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
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19
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Diagnostic differences in respiratory breathing patterns and work of breathing indices in children with Duchenne muscular dystrophy. PLoS One 2020; 15:e0226980. [PMID: 31923192 PMCID: PMC6953871 DOI: 10.1371/journal.pone.0226980] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 12/10/2019] [Indexed: 11/19/2022] Open
Abstract
Rationale Pulmonary function testing (PFT) provides diagnostic information regarding respiratory physiology. However, many forms of PFT are time-intensive and require patient cooperation. Respiratory inductance plethysmography (RIP) provides thoracoabdominal asynchrony (TAA) and work of breathing (WOB) data. pneuRIPTM is a noninvasive, wireless analyzer that provides real-time assessment of RIP via an iPad. In this study, we show that pneuRIPTM can be used in a hospital clinic setting to differentiate WOB indices and breathing patterns in children with DMD as compared to age-matched healthy subjects. Methods RIP using the pneuRIPTM was conducted on 9 healthy volunteers and 7 DMD participants (ages 5–18) recruited from the neuromuscular clinic, under normal resting conditions over 3–5 min during routine outpatient visits. The tests were completed in less than 10 minutes and did not add excessive time to the clinic visit. Variables recorded included labored-breathing index (LBI), phase angle (Φ) between abdomen and rib cage, respiratory rate (RR), percentage of rib cage input (RC%), and heart rate (HR). The data were displayed in histogram plots to identify distribution patterns within the normal ranges. The percentages of data within the ranges (0≤ Φ ≤30 deg.; median RC %±10%; median RR±5%; 1≤LBI≤1.1) were compared. Unpaired t-tests determined significance of the data between groups. Results 100% patient compliance demonstrates the feasibility of such testing in clinical settings. DMD patients showed a significant elevation in Φ, LBI, and HR averages (P<0.006, P<0.002, P<0.046, respectively). Healthy subjects and DMD patients had similar BPM and RC% averages. All DMD data distributions were statistically different from healthy subjects based on analysis of histograms. The DMD patients showed significantly less data within the normal ranges, with only 49.7% Φ, 48.0% RC%, 69.2% RR, and 50.7% LBI. Conclusion In this study, noninvasive pneuRIPTM testing provided instantaneous PFT diagnostic results. As compared to healthy subjects, patients with DMD showed abnormal results with increased markers of TAA, WOB indices, and different breathing patterns. These results are similar to previous studies evaluating RIP in preterm infants. Further studies are needed to compare these results to other pulmonary testing methods. The pneuRIPTM testing approach provides immediate diagnostic information in outpatient settings.
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20
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Fayssoil A, Chaffaut C, Ogna A, Stojkovic T, Lamothe L, Mompoint D, Meng P, Prigent H, Clair B, Behin A, Laforet P, Bassez G, Carlier R, Orlikowski D, Amthor H, Quijano Roy S, Crenn P, Chevret S, Eymard B, Lofaso F, Annane D. Echographic Assessment of Diaphragmatic Function in Duchenne Muscular Dystrophy from Childhood to Adulthood. J Neuromuscul Dis 2020; 6:55-64. [PMID: 30562904 DOI: 10.3233/jnd-180326] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic muscle disorder. Respiratory muscle function is classically affected in this disease. Ultrasound recently emerged as a non-invasive tool to assess diaphragm function. However, there are only a few studies using diaphragm ultrasound (US) in DMD. PURPOSE We aimed to assess diaphragm ultrasound patterns in DMD, their relationship with age and their association with home mechanical ventilation (HMV). METHODS We included DMD patients followed at Raymond Poincaré Hospital who benefited from diaphragm ultrasound and pulmonary function tests. RESULTS There were 110 DMD patients and 17 male sex-matched healthy subjects included. In all, 94% of patients were permanent wheelchair users. Median body mass index (BMI) was 18 kg/m2. DMD patients disclosed a reduced forced vital capacity (VC) (12% of predicted value), and 78% of patients were on HMV. In patients, right and left diaphragmatic motions on deep inspiration were reduced and end expiratory diaphragm thickness was borderline normal. In patients, right and left diaphragmatic thickening fractions (TF) were reduced 12.7% and 15.5%, respectively. Age and end expiratory thickness were significantly inversely associated (p = 0.005 for the right diaphragm, p = 0.018 for the left diaphragm). Diaphragm TF was significantly inversely associated with age (p = 0.001 for the right side, p < 0.0001 for the left side). Right and left inspiratory diaphragm motions were significantly inversely associated with age (p < 0.0001). CONCLUSION This study describes the severity of diaphragm dysfunction in patients with DMD. Diaphragm US may be a non-invasive outcome measure for DMD.
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Affiliation(s)
- Abdallah Fayssoil
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France.,Institut de Myologie, CHU Pitié Salpetrière, Paris, France
| | - Cendrine Chaffaut
- SBIM, CHU Saint Louis, APHP, Université Paris Diderot, Paris, France
| | - Adam Ogna
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | | | - Laure Lamothe
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Dominique Mompoint
- Service de Radiologie, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Paris Meng
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Helene Prigent
- Service de Physiologie - Explorations fonctionnelles, CHU Raymond Poincaré, APHP, Université de Versailles saint Quentin en Yvelines, Garches, France
| | - Bernard Clair
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Anthony Behin
- Institut de Myologie, CHU Pitié Salpetrière, Paris, France
| | - Pascal Laforet
- Institut de Myologie, CHU Pitié Salpetrière, Paris, France
| | | | - Robert Carlier
- Service de Radiologie, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - David Orlikowski
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France.,Centre d'Investigation clinique et Innovation technologique CIC 14.29, INSERM, Garches, France
| | - Helge Amthor
- Service de Pédiatrie, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Susana Quijano Roy
- Service de Pédiatrie, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Pascal Crenn
- Service de nutrition, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
| | - Sylvie Chevret
- SBIM, CHU Saint Louis, APHP, Université Paris Diderot, Paris, France
| | - Bruno Eymard
- Institut de Myologie, CHU Pitié Salpetrière, Paris, France
| | - Frederic Lofaso
- Service de Physiologie - Explorations fonctionnelles, CHU Raymond Poincaré, APHP, Université de Versailles saint Quentin en Yvelines, Garches, France
| | - Djillali Annane
- Service de Réanimation msédicale et unité de ventilation à domicile, CHU Raymond Poincaré, APHP, Université de Versailles Saint Quentin en Yvelines, Garches, France
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21
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Strandberg K, Ayoglu B, Roos A, Reza M, Niks E, Signorelli M, Fasterius E, Pontén F, Lochmüller H, Domingos J, Ala P, Muntoni F, Aartsma-Rus A, Spitali P, Nilsson P, Szigyarto CAK. Blood-derived biomarkers correlate with clinical progression in Duchenne muscular dystrophy. J Neuromuscul Dis 2020; 7:231-246. [PMID: 32390640 PMCID: PMC7369103 DOI: 10.3233/jnd-190454] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Duchenne Muscular Dystrophy is a severe, incurable disorder caused by mutations in the dystrophin gene. The disease is characterized by decreased muscle function, impaired muscle regeneration and increased inflammation. In a clinical context, muscle deterioration, is evaluated using physical tests and analysis of muscle biopsies, which fail to accurately monitor the disease progression. OBJECTIVES This study aims to confirm and asses the value of blood protein biomarkers as disease progression markers using one of the largest longitudinal collection of samples. METHODS A total of 560 samples, both serum and plasma, collected at three clinical sites are analyzed using a suspension bead array platform to assess 118 proteins targeted by 250 antibodies in microliter amount of samples. RESULTS Nine proteins are confirmed as disease progression biomarkers in both plasma and serum. Abundance of these biomarkers decreases as the disease progresses but follows different trajectories. While carbonic anhydrase 3, microtubule associated protein 4 and collagen type I alpha 1 chain decline rather constantly over time, myosin light chain 3, electron transfer flavoprotein A, troponin T, malate dehydrogenase 2, lactate dehydrogenase B and nestin plateaus in early teens. Electron transfer flavoprotein A, correlates with the outcome of 6-minutes-walking-test whereas malate dehydrogenase 2 together with myosin light chain 3, carbonic anhydrase 3 and nestin correlate with respiratory capacity. CONCLUSIONS Nine biomarkers have been identified that correlate with disease milestones, functional tests and respiratory capacity. Together these biomarkers recapitulate different stages of the disorder that, if validated can improve disease progression monitoring.
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Affiliation(s)
- Kristin Strandberg
- Department of Protein Science, School of Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Burcu Ayoglu
- Department of Protein Science, SciLifeLab, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Andreas Roos
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Leibniz-Institut für Analytische Wissenschaften (ISAS), Dortmund, Germany
| | - Mojgan Reza
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Erik Niks
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mirko Signorelli
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, The Netherlands
| | - Erik Fasterius
- Department of Protein Science, School of Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Fredrik Pontén
- Department of Immunology, SciLifeLab, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Hanns Lochmüller
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Department of Neuropediatrics and Muscle Disorders, Medical Center –University of Freiburg, Faculty of Medicine, Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAGCRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Joana Domingos
- The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, UK
| | - Pierpaolo Ala
- The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, UK
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, UK
- National Institute for Health Research, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Annemieke Aartsma-Rus
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Pietro Spitali
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter Nilsson
- Department of Protein Science, SciLifeLab, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Cristina Al-Khalili Szigyarto
- Department of Protein Science, School of Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
- Department of Protein Science, SciLifeLab, KTH-Royal Institute of Technology, Stockholm, Sweden
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22
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Khan N, Eliopoulos H, Han L, Kinane TB, Lowes LP, Mendell JR, Gordish-Dressman H, Henricson EK, McDonald CM. Eteplirsen Treatment Attenuates Respiratory Decline in Ambulatory and Non-Ambulatory Patients with Duchenne Muscular Dystrophy. J Neuromuscul Dis 2019; 6:213-225. [PMID: 30856119 PMCID: PMC6598025 DOI: 10.3233/jnd-180351] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) patients experience skeletal muscle degeneration, including respiratory muscles. Respiratory decline in glucocorticoid-treated DMD patients, measured by percent predicted forced vital capacity (FVC% p), is typically 5% annually in patients aged 10 to 18 years. OBJECTIVE Evaluate the effects of eteplirsen on FVC% p annual change in 3 trials versus matched Cooperative International Neuromuscular Research Group Duchenne Natural History Study (CINRG DNHS) controls. METHODS Eteplirsen studies 201/202 evaluated eligible ambulatory DMD patients for at least 4 years, study 204 evaluated primarily non-ambulatory DMD patients for 2 years, and ongoing study 301 is evaluating ambulatory DMD patients for 2 years (interim analysis is included). Eteplirsen-treated patients (n = 74) were amenable to exon 51 skipping and were receiving glucocorticoids. Three CINRG DNHS cohorts included: glucocorticoid-treated patients amenable to exon 51 skipping (Exon 51 CINRG DNHS; n = 20), all glucocorticoid-treated CINRG patients (All CINRG DNHS; n = 172), and all glucocorticoid-treated genotyped CINRG DNHS patients (Genotyped CINRG DNHS; n = 148). FVC% p assessments between ages 10 and <18 years were included for all patients; mixed-model analyses characterized FVC% p annual change. RESULTS FVC% p annual change was greater for CINRG DNHS Exon 51 controls (- 6.00) versus patients in studies 201/202, study 204, and study 301 (- 2.19, P < 0.001; - 3.66, P 0.004; and - 3.79, P 0.017, respectively). FVC% p annual change in all eteplirsen studies suggested treatment benefit compared with the Genotyped CINRG DNHS (- 5.67) and All CINRG DNHS (- 5.56) cohorts (P < 0.05, all comparisons). CONCLUSIONS Significant, clinically meaningful attenuation of FVC%p decline was observed in eteplirsen-treated patients versus CINRG DNHS controls.
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Affiliation(s)
- Navid Khan
- Sarepta Therapeutics, Inc., Cambridge, MA, USA
| | | | - Lixin Han
- Sarepta Therapeutics, Inc., Cambridge, MA, USA
| | - T Bernard Kinane
- Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| | | | | | - Heather Gordish-Dressman
- Center for Genetic Medicine, Children's National Health System and the George Washington University School of Medicine and Health Sciences, Washington DC, USA
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23
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N-acetylcysteine Decreases Fibrosis and Increases Force-Generating Capacity of mdx Diaphragm. Antioxidants (Basel) 2019; 8:antiox8120581. [PMID: 31771272 PMCID: PMC6943616 DOI: 10.3390/antiox8120581] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/10/2019] [Accepted: 11/21/2019] [Indexed: 02/06/2023] Open
Abstract
Respiratory muscle weakness occurs due to dystrophin deficiency in Duchenne muscular dystrophy (DMD). The mdx mouse model of DMD shows evidence of impaired respiratory muscle performance with attendant inflammation and oxidative stress. We examined the effects of N-acetylcysteine (NAC) supplementation on respiratory system performance in mdx mice. Eight-week-old male wild type (n = 10) and mdx (n = 20) mice were studied; a subset of mdx (n = 10) received 1% NAC in the drinking water for 14 days. We assessed breathing, diaphragm, and external intercostal electromyogram (EMG) activities and inspiratory pressure during ventilatory and non-ventilatory behaviours. Diaphragm muscle structure and function, cytokine concentrations, glutathione status, and mRNA expression were determined. Diaphragm force-generating capacity was impaired in mdx compared with wild type. Diaphragm muscle remodelling was observed in mdx, characterized by increased muscle fibrosis, immune cell infiltration, and central myonucleation. NAC supplementation rescued mdx diaphragm function. Collagen content and immune cell infiltration were decreased in mdx + NAC compared with mdx diaphragms. The cytokines IL-1β, IL-6 and KC/GRO were increased in mdx plasma and diaphragm compared with wild type; NAC decreased systemic IL-1β and KC/GRO concentrations in mdx mice. We reveal that NAC treatment improved mdx diaphragm force-generating capacity associated with beneficial anti-inflammatory and anti-fibrotic effects. These data support the potential use of NAC as an adjunctive therapy in human dystrophinopathies.
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24
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Kelley EF, Cross TJ, Snyder EM, McDonald CM, Hoffman EP, Bello L. Influence of β 2 adrenergic receptor genotype on risk of nocturnal ventilation in patients with Duchenne muscular dystrophy. Respir Res 2019; 20:221. [PMID: 31619245 PMCID: PMC6796481 DOI: 10.1186/s12931-019-1200-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/25/2019] [Indexed: 12/23/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease resulting in severe respiratory derangements. As such, DMD patients are at a high risk of nocturnal hypoventilation, thereby requiring nocturnal ventilation (NV). To this end, NV is an important clinical milestone in the management of DMD. Emerging evidence suggests that ß2 adrenergic receptors (ADRB2) may play a role in determining respiratory function, whereby more functional ADRB2 genotype variants (e.g., Gly16) are associated with improved pulmonary function and respiratory muscle strength. These findings suggest that the more functional ADRB2 genotype may help to preserve respiratory function in patients with DMD. The purpose of this study was to identify the influence of ADRB2 genotype on the risk of NV use in DMD. Data from the CINRG Duchenne Natural History Study including 175 DMD patients (3–25 yrs) were analyzed focusing on ADRB2 genotype variants. Time-to-event analyses were used to examine differences in the age at prescription of full-time NV use between genotypes. There were no differences between genotype groups in age, height, weight, corticosteroid use, proportion of ambulatory patients, or age at loss of ambulation. DMD patients expressing the Gly16 polymorphism had a significantly (P < 0.05) lower mean age at NV prescription compared with those patients expressing the Arg16 polymorphism (21.80 ± 0.59 yrs. vs 25.91 ± 1.31 yrs., respectively). In addition, a covariate-adjusted Cox model revealed that the Gly16 variant group possessed a 6.52-fold higher risk of full-time NV use at any given age compared with the Arg16 polymorphism group. These data suggest that genetic variations in the ADRB2 gene may influence the age at which DMD patients are first prescribed NV, whereby patients with the Gly16 polymorphism are more likely to require NV assistance at an earlier age than their Arg16 counterparts.
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Affiliation(s)
- Eli F Kelley
- Department of Kinesiology, University of Minnesota, Minneapolis, MN, USA. .,Department of Cardiovascular Diseases, Mayo Clinic, RO_GE_MN_10, 1216 2nd Street SW, Rochester, MN, 55902, USA.
| | - Troy J Cross
- Department of Cardiovascular Diseases, Mayo Clinic, RO_GE_MN_10, 1216 2nd Street SW, Rochester, MN, 55902, USA
| | - Eric M Snyder
- Department of Kinesiology, University of Minnesota, Minneapolis, MN, USA
| | - Craig M McDonald
- University of California Davis Medical Center, Sacramento, CA, USA
| | | | - Eric P Hoffman
- Binghamton University - SUNY, Binghamton, NY, USA.,Center for Genetic Medicine, Children's Research Institute, Children's National Health System, Washington, DC, USA
| | - Luca Bello
- Department of Neurosciences, University of Padova, Padova, Italy
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25
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Barnard AM, Lott DJ, Batra A, Triplett WT, Forbes SC, Riehl SL, Willcocks RJ, Smith BK, Vandenborne K, Walter GA. Imaging respiratory muscle quality and function in Duchenne muscular dystrophy. J Neurol 2019; 266:2752-2763. [PMID: 31350642 DOI: 10.1007/s00415-019-09481-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/17/2019] [Accepted: 07/18/2019] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Duchenne muscular dystrophy (DMD) is characterized by damage to muscles including the muscles involved in respiration. Dystrophic muscles become weak and infiltrated with fatty tissue, resulting in progressive respiratory impairment. The objective of this study was to assess respiratory muscle quality and function in DMD using magnetic resonance imaging and to determine the relationship to clinical respiratory function. METHODS Individuals with DMD (n = 36) and unaffected controls (n = 12) participated in this cross sectional magnetic resonance imaging study. Participants underwent dynamic imaging of the thorax to assess diaphragm and chest wall mobility and chemical shift-encoded imaging of the chest and abdomen to determine fatty infiltration of the accessory respiratory muscles. Additionally, clinical pulmonary function measures were obtained. RESULTS Thoracic cavity area was decreased in individuals with DMD compared to controls during tidal and maximal breathing. Individuals with DMD had reduced chest wall movement in the anterior-posterior direction during maximal inspirations and expirations, but diaphragm descent during maximal inspirations (normalized to height) was only decreased in a subset of individuals with maximal inspiratory pressures less than 60% predicted. Muscle fat fraction was elevated in all three expiratory muscles assessed (p < 0.001), and the degree of fatty infiltration correlated with percent predicted maximal expiratory pressures (r = - 0.70, p < 0.001). The intercostal muscles demonstrated minimal visible fatty infiltration; however, this analysis was qualitative and resolution limited. INTERPRETATION This magnetic resonance imaging investigation of diaphragm movement, chest wall movement, and accessory respiratory muscle fatty infiltration provides new insights into the relationship between disease progression and clinical respiratory function.
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Affiliation(s)
- Alison M Barnard
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
| | - Donovan J Lott
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Abhinandan Batra
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - William T Triplett
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Sean C Forbes
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Samuel L Riehl
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | | | - Barbara K Smith
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Krista Vandenborne
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA.
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26
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Comparison of Pulmonary Function Decline in Steroid-Treated and Steroid-Naïve Patients with Duchenne Muscular Dystrophy. J Pediatr 2019; 210:194-200.e2. [PMID: 30955791 DOI: 10.1016/j.jpeds.2019.02.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/07/2019] [Accepted: 02/26/2019] [Indexed: 11/23/2022]
Abstract
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.
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Khokhar A, Nair A, Midya V, Kumar A, Sinharoy A, Ahmad TA, Abu-Hasan M, Mondal P. Association between pulmonary function and left ventricular volume and function in duchenne muscular dystrophy. Muscle Nerve 2019; 60:286-291. [PMID: 31250930 DOI: 10.1002/mus.26623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/23/2019] [Accepted: 06/24/2019] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is characterized by absence of the subsarcolemmal protein dystrophin, present in skeletal muscles and cardiomyocytes. We hypothesized that progressive respiratory and left ventricular (LV) insufficiencies in DMD could be parallel and interrelated phenomena. METHODS We conducted a retrospective chart review of 27 patients with DMD. Our primary objective was to compare the rates of decline between pulmonary function test (PFT) measures (forced expiratory volume in the first second, forced vital capacity, peak expiratory flow rate, maximal inspiratory/expiratory pressure) and echocardiographic estimates of LV end-diastolic volume and LV ejection fraction. RESULTS The rates of decline/year of PFTs and LV estimates were not significantly different. Pulmonary function test measures of ventilatory efficiency and strength had strong intercorrelations. Pulmonary function tests and LV estimates had weak but statistically significant correlations. DISCUSSION A comparable rate of decline in PFTs and LV indices in DMD provides evidence for concurrently progressive deterioration in respiratory and LV functions. Muscle Nerve, 2019.
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Affiliation(s)
| | - Athira Nair
- Department of Pediatrics, Division of Pediatric Cardiology, University of California, San Francisco, California, USA
| | - Vishal Midya
- Department of Biostatistics and Bioinformatics, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Ashutosh Kumar
- Department of Pediatrics, Division of Pediatric Neurology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Ankita Sinharoy
- Department of Public Health, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Tariq Ali Ahmad
- Department of Medicine, Division of Cardiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Mutasim Abu-Hasan
- Department of Pediatrics, Division of Pulmonology, University of Florida, Gainesville, Florida, USA
| | - Pritish Mondal
- Department of Pediatrics, Division of Pediatric Pulmonology, Penn State College of Medicine, 500 University Drive, PO Box 850, Hershey, Pennsylvania, 17033, USA
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Khurram OU. Sharing the load: compensatory pressure generation in the mdx mouse model. J Physiol 2019; 597:4101-4102. [PMID: 31131877 DOI: 10.1113/jp278272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Obaid U Khurram
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
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Murphy S, Zweyer M, Raucamp M, Henry M, Meleady P, Swandulla D, Ohlendieck K. Proteomic profiling of the mouse diaphragm and refined mass spectrometric analysis of the dystrophic phenotype. J Muscle Res Cell Motil 2019; 40:9-28. [PMID: 30888583 DOI: 10.1007/s10974-019-09507-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/08/2019] [Indexed: 12/11/2022]
Abstract
The diaphragm is a crucial muscle involved in active inspiration and whole body homeostasis. Previous biochemical, immunochemical and cell biological investigations have established the distribution and fibre type-specific expression of key diaphragm proteins. Building on these findings, it was of interest to establish the entire experimentally assessable diaphragm proteome and verify the presence of specific protein isoforms within this specialized subtype of skeletal muscle. A highly sensitive Orbitrap Fusion Tribrid mass spectrometer was used for the systematic identification of the mouse diaphragm-associated protein population. Proteomics established 2925 proteins by high confidence peptide identification. Bioinformatics was used to determine the distribution of the main protein classes, biological processes and subcellular localization within the diaphragm proteome. Following the establishment of the respiratory muscle proteome with special emphasis on protein isoform expression in the contractile apparatus, the extra-sarcomeric cytoskeleton, the extracellular matrix and the excitation-contraction coupling apparatus, the mass spectrometric analysis of the diaphragm was extended to the refined identification of proteome-wide changes in X-linked muscular dystrophy. The comparative mass spectrometric profiling of the dystrophin-deficient diaphragm from the mdx-4cv mouse model of Duchenne muscular dystrophy identified 289 decreased and 468 increased protein species. Bioinformatics was employed to analyse the clustering of changes in protein classes and potential alterations in interaction patterns of proteins involved in metabolism, the contractile apparatus, proteostasis and the extracellular matrix. The detailed pathoproteomic profiling of the mdx-4cv diaphragm suggests highly complex alterations in a variety of crucial cellular processes due to deficiency in the membrane cytoskeletal protein dystrophin.
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Affiliation(s)
- Sandra Murphy
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.,Newcastle Fibrosis Research Group, Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Margit Zweyer
- Institute of Physiology II, University of Bonn, 53115, Bonn, Germany
| | - Maren Raucamp
- Institute of Physiology II, University of Bonn, 53115, Bonn, Germany
| | - Michael Henry
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Paula Meleady
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Dieter Swandulla
- Institute of Physiology II, University of Bonn, 53115, Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.
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Swallowing with Noninvasive Positive-Pressure Ventilation (NPPV) in Individuals with Muscular Dystrophy: A Qualitative Analysis. Dysphagia 2019; 35:32-41. [PMID: 30859305 DOI: 10.1007/s00455-019-09997-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 03/05/2019] [Indexed: 12/13/2022]
Abstract
The purpose of the study is to describe experiences of swallowing with two forms of noninvasive positive-pressure ventilation (NPPV): mouthpiece NPPV (M-NPPV) and nasal bilevel positive airway pressure (BPAP) in people with muscular dystrophy. Ten men (ages 22-42 years; M = 29.3; SD = 7.1) with muscular dystrophy (9 with Duchenne's; 1 with Becker's) completed the Eating Assessment Tool (EAT-10; Ann Otol Rhinol Laryngol 117(12):919-924 [33]) and took part in semi-structured interviews. The interviews were audio recorded, transcribed, and verified. Phenomenological qualitative research methods were used to code (Dedoose.com) and develop themes. All participants affirmed dysphagia symptoms via responses on the EAT-10 (M = 11.3; SD = 6.38; Range = 3-22) and reported eating and drinking with M-NPPV and, to a lesser extent, nasal BPAP. Analysis of interview data revealed three primary themes: (1) M-NPPV improves the eating/drinking experience: Most indicated that using M-NPPV reduced swallowing-related dyspnea. (2) NPPV affects breathing-swallowing coordination: Participants described challenges and compensations in coordinating swallowing with ventilator-delivered inspirations, and that the time needed to chew solid foods between ventilator breaths may lead to dyspnea and fatigue. (3) M-NPPV aids cough effectiveness: Participants described improved cough strength following large M-NPPV delivered inspirations (with or without breath stacking). Although breathing-swallowing coordination is challenging with NPPV, participants reported that eating and drinking is more comfortable than when not using it. Overall, eating and drinking with NPPV delivered via a mouthpiece is preferred and is likely safer for swallowing than with nasal BPAP. M-NPPV (but not nasal BPAP) is reported to improve cough effectiveness, an important pulmonary defense in this population.
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31
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Ricotti V, Selby V, Ridout D, Domingos J, Decostre V, Mayhew A, Eagle M, Butler J, Guglieri M, Van der Holst M, Jansen M, Verschuuren JJGM, de Groot IJM, Niks EH, Servais L, Straub V, Voit T, Hogrel JY, Muntoni F. Respiratory and upper limb function as outcome measures in ambulant and non-ambulant subjects with Duchenne muscular dystrophy: A prospective multicentre study. Neuromuscul Disord 2019; 29:261-268. [PMID: 30852071 DOI: 10.1016/j.nmd.2019.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 11/19/2022]
Abstract
The field of translational research in Duchenne muscular dystrophy (DMD) has been transformed in the last decade by a number of therapeutic targets, mostly studied in ambulant patients. A paucity of studies focus on measures that capture the non-ambulant stage of the disease, and the transition between the ambulant and non-ambulant phase. In this prospective natural history study, we report the results of a comprehensive assessment of respiratory, upper limb function and upper limb muscle strength in a group of 89 DMD boys followed in 3 European countries, 81 receiving corticosteroids, spanning a wide age range (5-18 years) and functional abilities, from ambulant (n = 60) to non-ambulant (n = 29). Respiratory decline could be detected in the early ambulatory phase using Peak Expiratory Flow percentage predicted (PEF%), despite glucocorticoid use (mean annual decline: 4.08, 95% CI [-7.44,-0.72], p = 0.02 in ambulant; 4.81, 95% CI [-6.79,-2.82], p < 0.001 in non-ambulant). FVC% captured disease progression in non-ambulant DMD subjects, with an annual loss of 5.47% (95% CI [-6.48,-4.45], p < 0.001). Upper limb function measured with the Performance of Upper Limb (PUL 1.2) showed an annual loss of 4.13 points (95% CI [-4.79,3.47], p < 0.001) in the non-ambulant cohort. Measures of upper limb strength (MyoGrip and MyoPinch) showed a continuous decline independent of the ambulatory status, when reported as percentage predicted (grip force -5.51%, 95% CI [-6.54,-4.48], p < 0.001 in ambulant and a slower decline -2.86%; 95% CI -3.29,-2.43, p < 0.001, in non-ambulant; pinch force: -2.66%, 95% CI [-3.82,-1.51], p < 0.001 in ambulant and -2.23%, 95% CI [-2.92,-1.53], p < 0.001 in non-ambulant). Furthermore, we also explored the novel concept of a composite endpoint by combining respiratory, upper limb function and force domains: we were able to identify clear clinical progression in patients in whom an isolated measurement of only one of these domains failed to appreciate the yearly change. Our study contributes to the field of natural history of DMD, linking the ambulant and non-ambulant phases of the disease, and suggests that composite scores should be explored further.
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Affiliation(s)
- V Ricotti
- NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, University College London, London, UK; Solid Biosciences, London, UK.
| | - V Selby
- NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, University College London, London, UK; Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, London, UK
| | - D Ridout
- NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, University College London, London, UK; Population, Policy and Practice Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - J Domingos
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, London, UK
| | - V Decostre
- Groupe Hospitalier Pitié Salpêtrière, Institut de Myologie, Paris, France
| | - A Mayhew
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle, UK
| | - M Eagle
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle, UK
| | - J Butler
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, London, UK
| | - M Guglieri
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle, UK
| | | | - M Jansen
- Department of Rehabilitation, Donders Centre of Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | | | - I J M de Groot
- Department of Rehabilitation, Donders Centre of Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - E H Niks
- Leiden University Medical Centre, Leiden, The Netherlands
| | - L Servais
- Groupe Hospitalier Pitié Salpêtrière, Institut de Myologie, Paris, France
| | - V Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle, UK
| | - T Voit
- NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, University College London, London, UK; Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, London, UK
| | - J Y Hogrel
- Groupe Hospitalier Pitié Salpêtrière, Institut de Myologie, Paris, France
| | - F Muntoni
- NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, University College London, London, UK; Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital Trust, London, UK.
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32
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Burns DP, Murphy KH, Lucking EF, O'Halloran KD. Inspiratory pressure-generating capacity is preserved during ventilatory and non-ventilatory behaviours in young dystrophic mdx mice despite profound diaphragm muscle weakness. J Physiol 2019; 597:831-848. [PMID: 30570134 DOI: 10.1113/jp277443] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/18/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Respiratory muscle weakness is a major feature of Duchenne muscular dystrophy (DMD), yet little is known about the neural control of the respiratory muscles in DMD and animal models of dystrophic disease. Substantial diaphragm muscle weakness is apparent in young (8-week-old) mdx mice, although ventilatory capacity in response to maximum chemostimulation in conscious mice is preserved. Peak volume- and flow-related measures during chemoactivation are equivalent in anaesthetized, vagotomized wild-type and mdx mice. Diaphragm and T3 external intercostal electromyogram activities are lower during protracted sustained airway occlusion in mdx compared to wild-type mice. Yet, peak inspiratory pressure generation is remarkably well preserved. Despite profound diaphragm weakness and lower muscle activation during maximum non-ventilatory efforts, inspiratory pressure-generating capacity is preserved in young adult mdx mice, revealing compensation in support of respiratory system performance that is adequate, at least early in dystrophic disease. ABSTRACT Diaphragm dysfunction is recognized in the mdx mouse model of muscular dystrophy; however, there is a paucity of information concerning the neural control of dystrophic respiratory muscles. In young adult (8 weeks of age) male wild-type and mdx mice, we assessed ventilatory capacity, neural activation of the diaphragm and external intercostal (EIC) muscles and inspiratory pressure-generating capacity during ventilatory and non-ventilatory behaviours. We hypothesized that respiratory muscle weakness is associated with impaired peak inspiratory pressure-generating capacity in mdx mice. Ventilatory responsiveness to hypercapnic hypoxia was determined in conscious mice by whole-body plethysmography. Diaphragm isometric and isotonic contractile properties were determined ex vivo. In anaesthetized mice, thoracic oesophageal pressure, and diaphragm and EIC electromyogram (EMG) activities were recorded during baseline conditions and sustained tracheal occlusion for 30-40s. Despite substantial diaphragm weakness, mdx mice retain the capacity to enhance ventilation during hypercapnic hypoxia. Peak volume- and flow-related measures were also maintained in anaesthetized, vagotomized mdx mice. Peak inspiratory pressure was remarkably well preserved during chemoactivated breathing, augmented breaths and maximal sustained efforts during airway obstruction in mdx mice. Diaphragm and EIC EMG activities were lower during airway obstruction in mdx compared to wild-type mice. We conclude that ventilatory capacity is preserved in young mdx mice. Despite profound respiratory muscle weakness and lower diaphragm and EIC EMG activities during high demand in mdx mice, peak inspiratory pressure is preserved, revealing adequate compensation in support of respiratory system performance, at least early in dystrophic disease. We suggest that a progressive loss of compensation during advancing disease, combined with diaphragm dysfunction, underpins the development of respiratory system morbidity in dystrophic diseases.
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Affiliation(s)
- David P Burns
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Kevin H Murphy
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
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33
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Sanchez FF, Araújo da Silva CD, de Souza Pereira Gama Maciel MC, Rebouças Demósthenes Marques J, Brosina de Leon E, Lins Gonçalves R. Predictive equations for respiratory muscle strength by anthropometric variables. CLINICAL RESPIRATORY JOURNAL 2018; 12:2292-2299. [PMID: 29729121 DOI: 10.1111/crj.12908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/19/2018] [Accepted: 04/22/2018] [Indexed: 11/25/2022]
Abstract
Recent studies have pointed out divergences in the predictive quality of reference equations for respiratory muscle strength, alerting the need to introduce into these equation-specific variables for certain target populations. OBJECTIVES This study proposes predictive equations of respiratory muscle strength by the variables such as body weight and body mass index (BMI = weight/height2 ). MATERIALS AND METHODS This is a cross-sectional study, and the evaluation was made by the test of maximum static respiratory pressures (MIP and MEP) according to standard protocol of the Brazilian Society of Pneumology and Tisiology. For data analysis, the following three models of linear regression were adjusted: age, age/weight, age/BMI. The software used in the analysis was the R version 3.2.1. RESULTS Of the 353 subjects evaluated (229 women and 124 men), 109 subjects were normal weight, 101 subjects were overweight and 143 subjects were obese. The BMI average of the individuals was 31.42 ± 10.26 kg/m2 and age 46.26 ± 16.47 years. The two statistical models that considered the variables weight and BMI had the R2 value of 29.86% for MEP and 21.77% for MIP when the weight was the predictive variable and 21.33% for MIP and 28.38% for MEP when the variable was BMI. CONCLUSION It was found with the adjusted models that there was a considerable gain in the predictive quality of the models for MEP and MIP adding weight or BMI, without significant difference between both.
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Affiliation(s)
- Fernanda Figueiroa Sanchez
- Federal University of Amazonas, UFAM, General Rodrigo Octavio Jordão Ramos Av., 1200-Coroado I, Manaus, AM 69067-005, Brazil
| | - Cássio Daniel Araújo da Silva
- Federal University of Amazonas, UFAM, General Rodrigo Octavio Jordão Ramos Av., 1200-Coroado I, Manaus, AM 69067-005, Brazil
| | | | | | - Elisa Brosina de Leon
- Federal University of Amazonas, UFAM, General Rodrigo Octavio Jordão Ramos Av., 1200-Coroado I, Manaus, AM 69067-005, Brazil
| | - Roberta Lins Gonçalves
- Federal University of Amazonas, UFAM, General Rodrigo Octavio Jordão Ramos Av., 1200-Coroado I, Manaus, AM 69067-005, Brazil
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McDonald CM, Gordish-Dressman H, Henricson EK, Duong T, Joyce NC, Jhawar S, Leinonen M, Hsu F, Connolly AM, Cnaan A, Abresch RT, Dubrovsky A, Kornberg A, Ryan M, Webster R, Biggar W, McAdam L, Mah J, Kolski H, Vishwanathan V, Chidambaranathan S, Nevo Y, Gorni K, Carlo J, Tulinius M, Lotze T, Bertorini T, Day J, Karachunski P, Clemens P, Abdel-Hamid H, Teasley J, Kuntz N, Driscoll S, Bodensteiner J, Connolly A, Pestronk A, Abresch R, Henricson E, Joyce N, McDonald C, Cnaan A, Morgenroth L, Leshner R, Tesi-Rocha C, Thangarajh M, Duong T. Longitudinal pulmonary function testing outcome measures in Duchenne muscular dystrophy: Long-term natural history with and without glucocorticoids. Neuromuscul Disord 2018; 28:897-909. [DOI: 10.1016/j.nmd.2018.07.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/24/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
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Burns DP, Canavan L, Rowland J, O'Flaherty R, Brannock M, Drummond SE, O'Malley D, Edge D, O'Halloran KD. Recovery of respiratory function in mdx mice co-treated with neutralizing interleukin-6 receptor antibodies and urocortin-2. J Physiol 2018; 596:5175-5197. [PMID: 30160301 PMCID: PMC6209753 DOI: 10.1113/jp276954] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 08/22/2018] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Impaired ventilatory capacity and diaphragm muscle weakness are prominent features of Duchenne muscular dystrophy, with strong evidence of attendant systemic and muscle inflammation. We performed a 2-week intervention in young wild-type and mdx mice, consisting of either injection of saline or co-administration of a neutralizing interleukin-6 receptor antibody (xIL-6R) and urocortin-2 (Ucn2), a corticotrophin releasing factor receptor 2 agonist. We examined breathing and diaphragm muscle form and function. Breathing and diaphragm muscle functional deficits are improved following xIL-6R and Ucn2 co-treatment in mdx mice. The functional improvements were associated with a preservation of mdx diaphragm muscle myosin heavy chain IIx fibre complement. The concentration of the pro-inflammatory cytokine interleukin-1β was reduced and the concentration of the anti-inflammatory cytokine interleukin-10 was increased in mdx diaphragm following drug co-treatment. Our novel findings may have implications for the development of pharmacotherapies for the dystrophinopathies with relevance for respiratory muscle performance and breathing. ABSTRACT The mdx mouse model of Duchenne muscular dystrophy shows evidence of hypoventilation and pronounced diaphragm dysfunction. Six-week-old male mdx (n = 32) and wild-type (WT; n = 32) mice received either saline (0.9% w/v) or a co-administration of neutralizing interleukin-6 receptor antibodies (xIL-6R; 0.2 mg kg-1 ) and corticotrophin-releasing factor receptor 2 agonist (urocortin-2; 30 μg kg-1 ) subcutaneously over 2 weeks. Breathing and diaphragm muscle contractile function (ex vivo) were examined. Diaphragm structure was assessed using histology and immunofluorescence. Muscle cytokine concentration was determined using a multiplex assay. Minute ventilation and diaphragm muscle peak force at 100 Hz were significantly depressed in mdx compared with WT. Drug treatment completely restored ventilation in mdx mice during normoxia and significantly increased mdx diaphragm force- and power-generating capacity. The number of centrally nucleated muscle fibres and the areal density of infiltrates and collagen content were significantly increased in mdx diaphragm; all indices were unaffected by drug co-treatment. The abundance of myosin heavy chain (MyHC) type IIx fibres was significantly decreased in mdx diaphragm; drug co-treatment preserved MyHC type IIx complement in mdx muscle. Drug co-treatment increased the cross-sectional area of MyHC type I and IIx fibres in mdx diaphragm. The cytokines IL-1β, IL-6, KC/GRO and TNF-α were significantly increased in mdx diaphragm compared with WT. Drug co-treatment significantly decreased IL-1β and increased IL-10 in mdx diaphragm. Drug co-treatment had no significant effect on WT diaphragm muscle structure, cytokine concentrations or function. Recovery of breathing and diaphragm force in mdx mice was impressive in our studies, with implication for human dystrophinopathies.
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Affiliation(s)
- David P. Burns
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Leonie Canavan
- Department of PhysiologySchool of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, the University of DublinDublinIreland
| | - Jane Rowland
- Department of PhysiologySchool of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, the University of DublinDublinIreland
| | - Robin O'Flaherty
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Molly Brannock
- Department of PhysiologySchool of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, the University of DublinDublinIreland
| | - Sarah E. Drummond
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Dervla O'Malley
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Deirdre Edge
- Department of PhysiologySchool of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, the University of DublinDublinIreland
| | - Ken D. O'Halloran
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
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Respiratory insight to congenital muscular dystrophies and congenital myopathies and its relation to clinical trial. Neuromuscul Disord 2018; 28:731-740. [DOI: 10.1016/j.nmd.2018.06.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/22/2018] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
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Mayer OH, Aliverti A, Meier T. Breathe Duchenne: what natural history studies tell us about the progression of pulmonary morbidity in Duchenne muscular dystrophy. Neuromuscul Disord 2018; 28:910-913. [PMID: 30266222 DOI: 10.1016/j.nmd.2018.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 11/24/2022]
Affiliation(s)
- Oscar H Mayer
- Division of Pulmonary Medicine, Pulmonary Function Testing Laboratory, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA.
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
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Araujo APQC, Nardes F, Fortes CPDD, Pereira JA, Rebel MF, Dias CM, Barbosa RDCGA, Lopes MVR, Langer AL, Neves FR, Reis EF. Brazilian consensus on Duchenne muscular dystrophy. Part 2: rehabilitation and systemic care. ARQUIVOS DE NEURO-PSIQUIATRIA 2018; 76:481-489. [DOI: 10.1590/0004-282x20180062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 04/30/2018] [Indexed: 12/19/2022]
Abstract
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.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Edna Fátima Reis
- Associação Brasileira de Distrofia Muscular Viver Bem sem Limite, Brasil; Associação de Assistência à Criança Deficiente, Brasil
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O'Halloran KD, Burns DP. Breathing with neuromuscular disease: Does compensatory plasticity in the motor drive to breathe offer a potential therapeutic target in muscular dystrophy? Respir Physiol Neurobiol 2018; 265:49-54. [PMID: 29933052 DOI: 10.1016/j.resp.2018.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 05/22/2018] [Accepted: 06/18/2018] [Indexed: 11/26/2022]
Abstract
Duchenne muscular dystrophy is a fatal neuromuscular disease associated with respiratory-related morbidity and mortality. Herein, we review recent work by our group exploring deficits and compensation in the respiratory control network governing respiratory homeostasis in a pre-clinical model of DMD, the mdx mouse. Deficits at multiple sites of the network provide considerable challenges to respiratory control. However, our work has also revealed evidence of compensatory neuroplasticity in the motor drive to breathe enhancing diaphragm muscle activity during increased chemical drive. The finding may explain the preserved capacity for mdx mice to increase ventilation in response to chemoactivation. Given the profound dysfunction in the primary pump muscle of breathing, we argue that activation of accessory muscles of breathing may be especially important in mdx (and perhaps DMD). Notwithstanding the limitations resulting from respiratory muscle dysfunction, it may be possible to further leverage intrinsic physiological mechanisms serving to compensate for weak muscles in attempts to preserve or restore ventilatory capacity. We discuss current knowledge gaps and the need to better appreciate fundamental aspects of respiratory control in pre-clinical models so as to better inform intervention strategies in human DMD.
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Affiliation(s)
- Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
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Kinane TB, Mayer OH, Duda PW, Lowes LP, Moody SL, Mendell JR. Long-Term Pulmonary Function in Duchenne Muscular Dystrophy: Comparison of Eteplirsen-Treated Patients to Natural History. J Neuromuscul Dis 2018; 5:47-58. [PMID: 29278896 PMCID: PMC5836407 DOI: 10.3233/jnd-170272] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background: Duchenne muscular dystrophy (DMD) is a rare, degenerative, X-linked genetic disease that results in progressive muscle loss and premature death, most commonly from respiratory or cardiac failure. DMD is primarily caused by whole exon deletions, resulting in a shift of the dystrophin mRNA reading frame that prevents production of functional dystrophin protein. Eteplirsen, a phosphorodiamidate morpholino oligomer (PMO), is designed to skip exon 51, restore the reading frame, and induce production of internally shortened dystrophin in patients with mutations amenable to such treatment. Objective: Describe lung function assessed throughout eteplirsen studies 201/202. Methods: Studies 201/202 included 12 patients treated with eteplirsen over 5 years. Pulmonary function tests included forced vital capacity (FVC), maximum expiratory pressure (MEP), and maximum inspiratory pressure (MIP). With no long-term placebo control, FVC results were compared with data from the United Dystrophinopathy Project (UDP). MIP and MEP were compared to published natural history. Results: Age-adjusted mixed-model repeated-measures analysis showed decreases of 2.3% and 2.6% annually for FVC% p and MEP% p, and an annual increase of 0.6% for MIP% p for the eteplirsen-treated cohort. Data from the UDP demonstrated a 4.1% decline in FVC% p. The published natural history reports annual declines of at least 2.7% and 3.8% for MEP% p and MIP% p, respectively, in patients with DMD. Conclusions: With eteplirsen treatment, deterioration of respiratory muscle function based on FVC% p was half of that seen in the UDP; MEP% p and MIP% p compared favorably with natural history.
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Affiliation(s)
- T Bernard Kinane
- Division of Pediatric Pulmonary, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, USA
| | - Oscar H Mayer
- Division of Pulmonology Pediatric Pulmonary, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Linda P Lowes
- Department of Neurology, Nationwide Children's Hospital, Columbus, OH, USA.,Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Rochester, NY, USA
| | | | - Jerry R Mendell
- Department of Neurology, Nationwide Children's Hospital, Columbus, OH, USA.,Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Rochester, NY, USA.,Department of Pediatrics and Neurology, Ohio State University, Columbus, OH, USA
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Zhang S, Mei QQ, Xin J, Zhang HY, Wu SW, Liu CF. The assessment of sniff nasal inspiratory pressure in patients with Duchenne muscular dystrophy in China. Brain Dev 2018; 40:391-396. [PMID: 29477801 DOI: 10.1016/j.braindev.2018.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/23/2018] [Accepted: 01/27/2018] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Progressive weakness of respiratory muscles remains one of the leading causes of death among patients with Duchenne muscular dystrophy (DMD). Currently, there are few pulmonary function data among Chinese DMD patients. This study was carried out to evaluate the sniff nasal inspiratory pressure (SNIP) change among a group of Chinese DMD patients, and compare it with the SNIP value of patients with neuromuscular disorders in other countries. METHODS SNIP data were collected in three research groups that consists of 581 subjects: 125 DMD boys who have taken steroid (Age 5.0-13.3, DMD-steroid group), 145 DMD steroid-naive boys (Age 5.0-13.9, DMD-nonsteroid group), and 311 healthy controls (Age 5.0-14.0, Control group). RESULTS The SNIP for DMD-nonsteroid group, DMD-steroid group and Control group were: 56.5 (±14.3) cm H2O,66.4 (±15.5) cm H2O and 78.9 (±21.5) respectively. The SNIP in the DMD-nonsteroid group became significantly different from that of the healthy controls since age 7.0-8.9. The significant difference of SNIP between DMD-steroid group and DMD-nonsteroid group at age 7.0-10.9. The peak value of SNIP in the DMD-nonsteroid group appeared at age 8.7, and decreased dramatically thereafter, while in DMD-steroid group and the Control group peaked at 10.2 years and 12.2 years respectively. There was a bit difference between SNIP in this group and that in previous researches which may be due to geographical distribution and ethnic backgrounds. CONCLUSION This study strengthens the previous findings that SNIP can be used to evaluate respiratory dysfunction during the early stage of young patients with neuromuscular disorders, and demonstrates that steroid is effective in slowing the decrease of SNIP in this group of Chinese DMD boys.
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Affiliation(s)
- Shu Zhang
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, China; Department of Neurology, General Hospital of Chinese People's Armed Police force, China
| | - Qian-Qian Mei
- Department of Neurology, General Hospital of Chinese People's Armed Police force, China
| | - Jing Xin
- Department of Neurology, General Hospital of Chinese People's Armed Police force, China
| | - Hong-Ying Zhang
- Department of Neurology, General Hospital of Chinese People's Armed Police force, China
| | - Shi-Wen Wu
- Department of Neurology, General Hospital of Chinese People's Armed Police force, China.
| | - Chun-Feng Liu
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, China.
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Witherick J, Brady S. Update on muscle disease. J Neurol 2018; 265:1717-1725. [DOI: 10.1007/s00415-018-8856-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/30/2018] [Indexed: 12/24/2022]
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Ripamonti E, D'Angelo G. Measurement of respiratory function decline in patients with Duchenne muscular dystrophy: a conjoint analysis. Neurodegener Dis Manag 2018; 8:89-96. [PMID: 29412787 DOI: 10.2217/nmt-2017-0052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
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.
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Affiliation(s)
| | - Grazia D'Angelo
- Unità Operativa Semplice Patologie Neuromuscolari, Riabilitazione Funzionale, IRCCS "E. Medea", Via Don Luigi Monza, 20, 23842 Bosisio Parini LC, Italy
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LoMauro A, Romei M, Gandossini S, Pascuzzo R, Vantini S, D'Angelo MG, Aliverti A. Evolution of respiratory function in Duchenne muscular dystrophy from childhood to adulthood. Eur Respir J 2018; 51:51/2/1701418. [PMID: 29437939 DOI: 10.1183/13993003.01418-2017] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/21/2017] [Indexed: 11/05/2022]
Abstract
In Duchenne muscular dystrophy (DMD), it is still to be determined if specific timepoints can be identified during the natural evolution of respiratory dysfunction from childhood to adulthood and if scoliosis, steroid therapy and nocturnal noninvasive mechanical ventilation (NIMV) have any effect on it.In a 7-year retrospective study performed on 115 DMD patients (6-24 years), evaluated once or twice per year, with 574 visits in total, evolution mean curves of spirometry, lung volumes, spontaneous breathing and thoraco-abdominal pattern (measured by optoelectronic plethysmography) parameters were obtained by nonlinear regression model analysis.While predicted values of forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow decline continuously since childhood, during spontaneous breathing the following parameters become significantly different than normal in sequence: abdominal contribution to tidal volume (lower after 14.8 years), tidal volume (lower after 17.2 years), minute ventilation (lower after 18.1 years) and respiratory rate (higher after 22.1 years). Restrictive lung pattern and diaphragmatic impairment are exacerbated by scoliosis severity, slowed by steroids treatment and significantly affected by NIMV.Spirometry, lung volumes, breathing pattern and thoraco-abdominal contributions show different evolution curves over time. Specific timepoints of respiratory impairment are identified during disease progression. These should be considered when defining outcome measures in clinical trials and treatment strategies in DMD.
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Affiliation(s)
- Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Marianna Romei
- Istituto di Ricerca e Cura a Carattere Scientifico "E. Medea", Bosisio Parini, Italy
| | - Sandra Gandossini
- Istituto di Ricerca e Cura a Carattere Scientifico "E. Medea", Bosisio Parini, Italy
| | | | - Simone Vantini
- MOX-Department of Mathematics, Politecnico di Milano, Milano, Italy
| | - Maria Grazia D'Angelo
- Istituto di Ricerca e Cura a Carattere Scientifico "E. Medea", Bosisio Parini, Italy
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
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Abstract
PURPOSE OF REVIEW Understanding the mechanisms and abnormalities of respiratory function in neuromuscular disease is critical to supporting the patient and maintaining ventilation in the face of acute or chronic progressive impairment. RECENT FINDINGS Retrospective clinical studies reviewing the care of patients with Guillain-Barré syndrome and myasthenia have shown a disturbingly high mortality following step-down from intensive care. This implies high dependency and rehabilitation management is failing despite evidence that delayed improvement can occur with long-term care. A variety of mechanisms of phrenic nerve impairment have been recognized with newer investigation techniques, including EMG and ultrasound. Specific treatment for progressive neuromuscular and muscle disease has been increasingly possible particularly for the treatment of myasthenia, metabolic myopathies, and Duchenne muscular dystrophy. For those conditions without specific treatment, it has been increasingly possible to support ventilation in the domiciliary setting with newer techniques of noninvasive ventilation and better airway clearance. There remained several areas of vigorous debates, including the role for tracheostomy care and the place of respiratory muscle training and phrenic nerve/diaphragm pacing. SUMMARY Recent studies and systematic reviews have defined criteria for anticipating, recognizing, and managing ventilatory failure because of acute neuromuscular disease. The care of patients requiring long-term noninvasive ventilatory support for chronic disorders has also evolved. This has resulted in significantly improved survival for patients requiring domiciliary ventilatory support.
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Deflazacort in Duchenne muscular dystrophy: a profile of its use in the USA. DRUGS & THERAPY PERSPECTIVES 2018. [DOI: 10.1007/s40267-017-0466-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Tempol Supplementation Restores Diaphragm Force and Metabolic Enzyme Activities in mdx Mice. Antioxidants (Basel) 2017; 6:antiox6040101. [PMID: 29210997 PMCID: PMC5745511 DOI: 10.3390/antiox6040101] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/19/2017] [Accepted: 11/28/2017] [Indexed: 12/29/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is characterized by striated muscle weakness, cardiomyopathy, and respiratory failure. Since oxidative stress is recognized as a secondary pathology in DMD, the efficacy of antioxidant intervention, using the superoxide scavenger tempol, was examined on functional and biochemical status of dystrophin-deficient diaphragm muscle. Diaphragm muscle function was assessed, ex vivo, in adult male wild-type and dystrophin-deficient mdx mice, with and without a 14-day antioxidant intervention. The enzymatic activities of muscle citrate synthase, phosphofructokinase, and lactate dehydrogenase were assessed using spectrophotometric assays. Dystrophic diaphragm displayed mechanical dysfunction and altered biochemical status. Chronic tempol supplementation in the drinking water increased diaphragm functional capacity and citrate synthase and lactate dehydrogenase enzymatic activities, restoring all values to wild-type levels. Chronic supplementation with tempol recovers force-generating capacity and metabolic enzyme activity in mdx diaphragm. These findings may have relevance in the search for therapeutic strategies in neuromuscular disease.
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Goemans N, Mercuri E, Belousova E, Komaki H, Dubrovsky A, McDonald CM, Kraus JE, Lourbakos A, Lin Z, Campion G, Wang SX, Campbell C. A randomized placebo-controlled phase 3 trial of an antisense oligonucleotide, drisapersen, in Duchenne muscular dystrophy. Neuromuscul Disord 2017; 28:4-15. [PMID: 29203355 DOI: 10.1016/j.nmd.2017.10.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/23/2017] [Accepted: 10/17/2017] [Indexed: 01/16/2023]
Abstract
This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged ≥5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.415) in the change from baseline in six-minute walk distance (6MWD; primary efficacy endpoint) of 10.3 meters in favor of drisapersen was observed at week 48. Key secondary efficacy endpoints (North Star Ambulatory Assessment, 4-stair climb ascent velocity, and 10-meter walk/run velocity) gave consistent findings. Lack of statistical significance was thought to be largely due to greater data variability and subgroup heterogeneity. The increased standard deviation alone, due to less stringent inclusion/exclusion criteria, reduced the statistical power from pre-specified 90% to actual 53%. Therefore, a post-hoc analysis was performed in 80 subjects with a baseline 6MWD 300-400 meters and ability to rise from floor. A statistically significant improvement in 6MWD of 35.4 meters (P = 0.039) in favor of drisapersen was observed in this subpopulation. Results suggest that drisapersen could have benefit in a less impaired population of DMD subjects.
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Affiliation(s)
- Nathalie Goemans
- Department of Pediatrics and Child Neurology, University Hospitals Leuven, Leuven, Belgium.
| | | | - Elena Belousova
- Research and Clinical Institute of Pediatrics, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Hirofumi Komaki
- Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Alberto Dubrovsky
- Fundacion Cenit, Instituto de Neurociencias, Fundación Favaloro, Buenos Aires, Argentina
| | - Craig M McDonald
- School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - John E Kraus
- GlaxoSmithKline, Research Triangle Park, NC, USA
| | | | | | | | | | - Craig Campbell
- Paediatric Neurology, Schulich School of Medicine, Western University, London, Canada
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Respiratory functional and motor control deficits in children with spinal cord injury. Respir Physiol Neurobiol 2017; 247:174-180. [PMID: 29107737 DOI: 10.1016/j.resp.2017.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/09/2017] [Accepted: 10/16/2017] [Indexed: 12/18/2022]
Abstract
Children with spinal cord injury (SCI) are at high risk for developing complications due to respiratory motor control deficits. However, underlying mechanisms of these abnormalities with respect to age, development, and injury characteristics are unclear. To evaluate the effect of SCI and age on respiratory motor control in children with SCI, we compared pulmonary function and respiratory motor control outcome measures in healthy typically developing (TD) children to age-matched children with chronic SCI. We hypothesized that the deficits in respiratory functional performance in children with SCI are due to the abnormal and age-dependent respiratory muscle activation patterns. Fourteen TD (age 7±2 yrs., Mean±SD) and twelve children with SCI (age 6±1 yrs.) were evaluated by assessing Forced Vital Capacity (FVC); Forced Expiratory Volume in 1sec (FEV1); and respiratory electromyographic activity during maximum inspiratory and maximum expiratory airway pressure measurements (PImax and PEmax). The results indicate a significant reduction (p<.01) of FVC, FEV1 and PEmax values in children with SCI compared to TD controls. During PEmax assessment, children with SCI produced significantly decreased (p<.01) activation of respiratory muscles below the neurological level of injury (rectus abdominous and external oblique muscles). In addition, children with SCI had significantly increased (p<.05) compensatory muscle activation above the level of injury (upper trapezius muscle). In the TD group, age, height, and weight significantly (p<.05) contributed towards increase in FVC and FEV1. In children with SCI, only age was significantly (p<.05) correlated with FVC and FEV1 values. These findings indicate the degree of SCI-induced respiratory functional and motor control deficits in children are age-dependent.
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Burns DP, Roy A, Lucking EF, McDonald FB, Gray S, Wilson RJ, Edge D, O'Halloran KD. Sensorimotor control of breathing in the mdx mouse model of Duchenne muscular dystrophy. J Physiol 2017; 595:6653-6672. [PMID: 28952155 DOI: 10.1113/jp274792] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 09/07/2017] [Indexed: 01/05/2023] Open
Abstract
KEY POINTS Respiratory failure is a leading cause of mortality in Duchenne muscular dystrophy (DMD), but little is known about the control of breathing in DMD and animal models. We show that young (8 weeks of age) mdx mice hypoventilate during basal breathing due to reduced tidal volume. Basal CO2 production is equivalent in wild-type and mdx mice. We show that carotid bodies from mdx mice have blunted responses to hyperoxia, revealing hypoactivity in normoxia. However, carotid body, ventilatory and metabolic responses to hypoxia are equivalent in wild-type and mdx mice. Our study revealed profound muscle weakness and muscle fibre remodelling in young mdx diaphragm, suggesting severe mechanical disadvantage in mdx mice at an early age. Our novel finding of potentiated neural motor drive to breathe in mdx mice during maximal chemoactivation suggests compensatory neuroplasticity enhancing respiratory motor output to the diaphragm and probably other accessory muscles. ABSTRACT Patients with Duchenne muscular dystrophy (DMD) hypoventilate with consequential arterial blood gas derangement relevant to disease progression. Whereas deficits in DMD diaphragm are recognized, there is a paucity of knowledge in respect of the neural control of breathing in dystrophinopathies. We sought to perform an analysis of respiratory control in a model of DMD, the mdx mouse. In 8-week-old male wild-type and mdx mice, ventilation and metabolism, carotid body afferent activity, diaphragm muscle force-generating capacity, and muscle fibre size, distribution and centronucleation were determined. Diaphragm EMG activity and responsiveness to chemostimulation was determined. During normoxia, mdx mice hypoventilated, owing to a reduction in tidal volume. Basal CO2 production was not different between wild-type and mdx mice. Carotid sinus nerve responses to hyperoxia were blunted in mdx, suggesting hypoactivity. However, carotid body, ventilatory and metabolic responses to hypoxia were equivalent in wild-type and mdx mice. Diaphragm force was severely depressed in mdx mice, with evidence of fibre remodelling and damage. Diaphragm EMG responses to chemoactivation were enhanced in mdx mice. We conclude that there is evidence of chronic hypoventilation in young mdx mice. Diaphragm dysfunction confers mechanical deficiency in mdx resulting in impaired capacity to generate normal tidal volume at rest and decreased absolute ventilation during chemoactivation. Enhanced mdx diaphragm EMG responsiveness suggests compensatory neuroplasticity facilitating respiratory motor output, which may extend to accessory muscles of breathing. Our results may have relevance to emerging treatments for human DMD aiming to preserve ventilatory capacity.
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Affiliation(s)
- David P Burns
- Department of Physiology, University College Cork, Cork, Ireland
| | - Arijit Roy
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Eric F Lucking
- Department of Physiology, University College Cork, Cork, Ireland
| | - Fiona B McDonald
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Sam Gray
- Department of Physiology, Trinity Biosciences Institute, Trinity College Dublin, the University of Dublin, Dublin, Ireland
| | - Richard J Wilson
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Deirdre Edge
- Department of Physiology, Trinity Biosciences Institute, Trinity College Dublin, the University of Dublin, Dublin, Ireland
| | - Ken D O'Halloran
- Department of Physiology, University College Cork, Cork, Ireland
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