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Ippolito C, Canthiya L, Floreani A, Luckhart K, Hoffman A, McAdam L. Twice-Weekly Outpatient Rehabilitation Intervention for Young Children With Spinal Muscular Atrophy Treated With Genetic-Based Therapies: Protocol for a Feasibility Study. JMIR Res Protoc 2023; 12:e46363. [PMID: 37917140 PMCID: PMC10654912 DOI: 10.2196/46363] [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: 02/10/2023] [Revised: 09/01/2023] [Accepted: 09/08/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder that causes muscle weakness and is the leading genetic cause of infant mortality worldwide. While no definitive cure exists, the approval of 3 genetic-based therapies in Canada since 2018 has led to significant improvements in muscle function for children with SMA. With that, there are no evidence-based rehabilitation interventions and minimal evidence on the combined effects of genetic-based therapies and rehabilitation. OBJECTIVE This protocol describes the methodology to assess the feasibility of a twice-weekly outpatient rehabilitation intervention focusing on gross and fine motor function to inform the methodology and sample size of a definitive clinical trial. METHODS We will conduct a single-center nonrandomized pilot and feasibility trial to explore an outpatient rehabilitation intervention for children aged 6 months to 3 years with SMA treated with genetic-based therapies. Participation in the study will occur over a 25-week period, with a baseline assessment visit followed by a 12-week intervention period and a 12-week nonintervention period. The rehabilitation intervention comprises weekly physical and occupational therapy for 11 weeks. Assessments will occur at baseline (week 0), end of intervention or early withdrawal (week 12), and follow-up (week 24). Predetermined feasibility indicators will evaluate study feasibility across process (recruitment rates, eligibility criteria, adherence rates, retention rates, questionnaire suitability, and acceptability), resource (time, implementation, and execution), management (materials and data), and scientific (safety, tolerability, and preliminary efficacy) domains. RESULTS This project was funded in March 2022, and data will be collected between March 2023 and December 2023. Data analysis will occur between January 2024 and March 2024, with publication expected in the fall of 2024. The protocol for the feasibility trial will be considered successful if it meets the success criteria set out for the feasibility indicators. Indicators of specific interest include all process indicators, as well as time. Exploratory indicators will be reported. Pragmatically, the results of the feasibility trial will inform changes to the protocol and the start-up of a definitive multisite trial. CONCLUSIONS This novel twice-weekly outpatient rehabilitation intervention will be the first step toward filling the need for an evidence-based rehabilitation intervention for children with SMA treated with genetic-based therapies. It is expected that consistent and intensive rehabilitation therapy will augment functional gains being observed in this population. In the future, a definitive trial will measure the efficacy of the intervention. TRIAL REGISTRATION ClinicalTrials.gov NCT05638750; https://clinicaltrials.gov/study/NCT05638750. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/46363.
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Affiliation(s)
- Christina Ippolito
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
| | - Lathushikka Canthiya
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
| | - Amanda Floreani
- Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
| | | | - Andrea Hoffman
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
- Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Laura McAdam
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
- Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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Zilio E, Piano V, Wirth B. Mitochondrial Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2022; 23:ijms231810878. [PMID: 36142791 PMCID: PMC9503857 DOI: 10.3390/ijms231810878] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by recessive mutations in the SMN1 gene, globally affecting ~8-14 newborns per 100,000. The severity of the disease depends on the residual levels of functional survival of motor neuron protein, SMN. SMN is a ubiquitously expressed RNA binding protein involved in a plethora of cellular processes. In this review, we discuss the effects of SMN loss on mitochondrial functions in the neuronal and muscular systems that are the most affected in patients with spinal muscular atrophy. Our aim is to highlight how mitochondrial defects may contribute to disease progression and how restoring mitochondrial functionality may be a promising approach to develop new therapies. We also collected from previous studies a list of transcripts encoding mitochondrial proteins affected in various SMA models. Moreover, we speculate that in adulthood, when motor neurons require only very low SMN levels, the natural deterioration of mitochondria associated with aging may be a crucial triggering factor for adult spinal muscular atrophy, and this requires particular attention for therapeutic strategies.
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Affiliation(s)
- Eleonora Zilio
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Valentina Piano
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
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Bulut N, Karaduman A, Alemdaroğlu-Gürbüz İ, Yılmaz Ö, Topaloğlu H, Özçakar L. The effect of aerobic training on motor function and muscle architecture in children with Duchenne muscular dystrophy: A randomized controlled study. Clin Rehabil 2022; 36:1062-1071. [PMID: 35443813 DOI: 10.1177/02692155221095491] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To explore the effects of aerobic training adding to home-based exercise program on motor function and muscle architectural properties in children with Duchenne muscular dystrophy. DESIGN This is a prospective randomized controlled study. SETTING Pediatric neuromuscular clinic in a tertiary care center. SUBJECTS Children with Duchenne muscular dystrophy. INTERVENTIONS Children were randomly divided into two groups whereby 12-weeks aerobic training was additionally given in treatment group in contrast to the control group which received only home-based exercise program. MAIN MEASURES Motor Function Measure and Six Minute Walk Test were used for clinical evaluation, and muscle architectural properties (thickness, pennation angle and fascicle length) were measured by ultrasound imaging. Both groups were assessed at baseline and after 12-weeks of training. RESULTS Median age of children was 7.9 years in the treatment group and 8.6 years in the control group (p > 0.05). Significant improvements were obtained for Motor Function Measure and Six Minute Walk Test from baseline to 12-weeks in the treatment group; Motor Function Measure total score changed from 83.2 (6.1) to 86.9 (4.0) vs. 82.3 (10.2) to 80.4 (9.4) points in the control group (p = 0.006); 6 Minute Walk Test distance changed from 395.3 (46.6) to 413.0 (52.3) vs. 421.7 (64.4) to 393.8 (68.2) meters in the control group (p < 0.001). However, muscle architectural parameters did not change during study period (p > 0.05). CONCLUSION Aerobic training may be of additional value in improving motor function and performance with no remarkable effect on muscle architectural properties.
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Affiliation(s)
- Numan Bulut
- Faculty of Physical Therapy and Rehabilitation, 37515Hacettepe University, Ankara, Turkey
| | - Ayşe Karaduman
- Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Lokman Hekim University, Ankara, Turkey
| | | | - Öznur Yılmaz
- Faculty of Physical Therapy and Rehabilitation, 37515Hacettepe University, Ankara, Turkey
| | - Haluk Topaloğlu
- Department of Pediatrics, Division of Pediatric Neurology, Yeditepe University Hospital, İstanbul, Turkey
| | - Levent Özçakar
- Department of Physical Medicine and Rehabilitation, 37515Hacettepe University Medical School, Ankara, Turkey
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Abdelbasset WK, Elsayed SH, Nambi G, Alqahtani BA, Osailan AM, Azab AR, Moawd SA, Ali ZA, Verma A, Hussein RS, Eid MM. Optimization of pulmonary function, functional capacity, and quality of life in adolescents with thoracic burns after a 2-month arm cycling exercise programme: A randomized controlled study. Burns 2022; 48:78-84. [PMID: 33849715 DOI: 10.1016/j.burns.2021.03.010] [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: 12/12/2020] [Revised: 02/22/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Burns to the thorax are at high risk for long-term pulmonary complications due to chest muscle contractures and chronic inflammation in both adolescents and young adults. Few studies have investigated the effects of arm cycling exercise in those individuals. For that reason, this study examined pulmonary function, functional capacity, and quality of life (QOL) in adolescents with thoracic burns subsequent to 2-month arm cycling exercise programme. METHODS A single-blinded, two-month randomized prospective controlled study was carried out between July 2019 and March 2020 on thirty adolescents with chest burns aged 11-17 years. They were randomized into two equal groups (n = 15), traditional physiotherapy programme (control group), and arm cycling exercise plus traditonal physiotherapy (arm cycling exercise group) for 2 consecutive months. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), six-minute walk test (6MWT), and Pediatric Quality of Life Inventory (PedsQL) were measured in both groups at baseline and after 2-month after intervention. RESULTS No statistical significance was detected at baseline between control and arm cycling exercise groups (FVC, p = 0.903, FEV1, p = 0.835, 6MWT, p = 0.817, and PedsQL, p = 0.612). 2 months after intervention showed statistical improvements in the arm cycling exercise group in all measures (FVC, p = 0.001, FEV1, p < 0.0001, 6MWT, p = 0.001, and PedsQL, p = 0.001) however, the control group showed statistical improvements in FVC, p = 0.044 and FEV1, p = 0.024 with non-statistically significant changes in 6MWT, p = 0.145 and PedsQL, p = 0.067. The arm cycling exercise group showed greater improvements than control group in the outcome measures (FVC, p = 0.034, FEV1, p < 0.017, 6MWT, p = 0.037, and PedsQL, p = 0.021). CONCLUSIONS This prospective study clearly demonstrated positive and beneficial influences of two-month arm cycling exercise in the optimization of pulmonary functions, functional performance, and QOL in adolescents suffering from chest burns and thereby eliminating post-burn complications.
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Affiliation(s)
- Walid Kamal Abdelbasset
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia; Department of Physical Therapy, Kasr Al-Aini Hospital, Cairo University, Giza, Egypt.
| | - Shereen H Elsayed
- Department of Rehabilitation Sciences, Faculty of Health and Rehabilitation Sciences, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Gopal Nambi
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Bader A Alqahtani
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Ahmad M Osailan
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Alshimaa R Azab
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia; Department of Physical Therapy for Pediatrics, Faculty of Physical Therapy, Cairo University, Giza, Egypt
| | - Samah A Moawd
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia; Department of Physical Therapy for Cardiovascular/Respiratory Disorders and Geriatrics, Faculty of Physical Therapy, Cairo University, Giza, Egypt
| | - Zeinab A Ali
- Department of Physical Therapy for Surgery, Faculty of Physical Therapy, Cairo University, Giza, Egypt; Department of Physical Therapy, College of Applied Medical Sciences in Al-Qurayyat, Jouf University, Saudi Arabia
| | - Anju Verma
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Ramadan S Hussein
- Department of Internal Medicine, College of Medicine, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Marwa M Eid
- Department of Physical Therapy for Surgery, Faculty of Physical Therapy, Cairo University, Giza, Egypt; Department of Physical Therapy, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
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Trenkle J, Brugman J, Peterson A, Roback K, Krosschell KJ. Filling the gaps in knowledge translation: Physical therapy recommendations for individuals with spinal muscular atrophy compared to standard of care guidelines. Neuromuscul Disord 2021; 31:397-408. [PMID: 33741230 DOI: 10.1016/j.nmd.2021.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/17/2021] [Accepted: 02/11/2021] [Indexed: 11/17/2022]
Abstract
This study describes the current landscape of physical therapy practice recommendations in the United States for children with spinal muscular atrophy (SMA) and their relationship to current SMA standard of care (SMA-SOC) guidelines. Pediatric physical therapists were surveyed to determine their knowledge of SMA-SOC guidelines, and the type, duration and frequency of intervention they recommend for children with SMA, as well as perceived barriers and facilitators to progress in physical therapy. Physical therapists recommend five key intervention areas for individuals with SMA; however discrepancies exist between the SOC recommended intervention parameters and respondents' reported frequency and duration of recommendations. After individuals with SMA initiated disease modifying pharmacotherapies, a majority of physical therapist respondents recommended increases in both frequency and duration of interventions. Nearly all respondents reported that familiarity with SOC guidelines was beneficial to their practice. The primary facilitator to progress was parent/caregiver support, while the primary barrier was limited access to resources. Variation in practice exists regarding care for those with SMA, particularly in the areas of frequency and duration of specific interventions. These findings can guide educational initiatives, identify future research needs and further inform SMA-SOC and best-practice rehabilitation management.
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Affiliation(s)
- Jessica Trenkle
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Jessica Trenkle, LLC, United States
| | - Jessica Brugman
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Anne Peterson
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Katherine Roback
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Kristin J Krosschell
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.
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In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:brainsci11020194. [PMID: 33562482 PMCID: PMC7915832 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
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Houdebine L, D'Amico D, Bastin J, Chali F, Desseille C, Rumeau V, Soukkari J, Oudot C, Rouquet T, Bariohay B, Roux J, Sapaly D, Weill L, Lopes P, Djouadi F, Bezier C, Charbonnier F, Biondi O. Low-Intensity Running and High-Intensity Swimming Exercises Differentially Improve Energy Metabolism in Mice With Mild Spinal Muscular Atrophy. Front Physiol 2019; 10:1258. [PMID: 31632295 PMCID: PMC6781613 DOI: 10.3389/fphys.2019.01258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022] Open
Abstract
Spinal Muscular Atrophy (SMA), an autosomal recessive neurodegenerative disease characterized by the loss of spinal-cord motor-neurons, is caused by mutations on Survival-of-Motor Neuron (SMN)-1 gene. The expression of SMN2, a SMN1 gene copy, partially compensates for SMN1 disruption due to exon-7 excision in 90% of transcripts subsequently explaining the strong clinical heterogeneity. Several alterations in energy metabolism, like glucose intolerance and hyperlipidemia, have been reported in SMA at both systemic and cellular level, prompting questions about the potential role of energy homeostasis and/or production involvement in disease progression. In this context, we have recently reported the tolerance of mild SMA-like mice (SmnΔ7/Δ7; huSMN2+/+) to 10 months of low-intensity running or high-intensity swimming exercise programs, respectively involving aerobic and a mix aerobic/anaerobic muscular metabolic pathways. Here, we investigated whether those exercise-induced benefits were associated with an improvement in metabolic status in mild SMA-like mice. We showed that untrained SMA-like mice exhibited a dysregulation of lipid metabolism with an enhancement of lipogenesis and adipocyte deposits when compared to control mice. Moreover, they displayed a high oxygen consumption and energy expenditure through β-oxidation increase yet for the same levels of spontaneous activity. Interestingly, both exercises significantly improved lipid metabolism and glucose homeostasis in SMA-like mice, and enhanced oxygen consumption efficiency with the maintenance of a high oxygen consumption for higher levels of spontaneous activity. Surprisingly, more significant effects were obtained with the high-intensity swimming protocol with the maintenance of high lipid oxidation. Finally, when combining electron microscopy, respiratory chain complexes expression and enzymatic activity measurements in muscle mitochondria, we found that (1) a muscle-specific decreased in enzymatic activity of respiratory chain I, II, and IV complexes for equal amount of mitochondria and complexes expression and (2) a significant decline in mitochondrial maximal oxygen consumption, were reduced by both exercise programs. Most of the beneficial effects were obtained with the high-intensity swimming protocol. Taking together, our data support the hypothesis that active physical exercise, including high-intensity protocols, induces metabolic adaptations at both systemic and cellular levels, providing further evidence for its use in association with SMN-overexpressing therapies, in the long-term care of SMA patients.
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Affiliation(s)
- Léo Houdebine
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Domenico D'Amico
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Jean Bastin
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Farah Chali
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Céline Desseille
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Valentin Rumeau
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Judy Soukkari
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Carole Oudot
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Thaïs Rouquet
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Bruno Bariohay
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Julien Roux
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Delphine Sapaly
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Laure Weill
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Philippe Lopes
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France.,UFR STAPS, Université d'Evry Val-d'Essonne, Evry, France
| | - Fatima Djouadi
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Cynthia Bezier
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France.,Biophytis, Sorbonne Université, Paris, France
| | - Frédéric Charbonnier
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Olivier Biondi
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
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Sun J, Harrington MA. The Alteration of Intrinsic Excitability and Synaptic Transmission in Lumbar Spinal Motor Neurons and Interneurons of Severe Spinal Muscular Atrophy Mice. Front Cell Neurosci 2019; 13:15. [PMID: 30792629 PMCID: PMC6374350 DOI: 10.3389/fncel.2019.00015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/16/2019] [Indexed: 01/22/2023] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of death in infants. Studies with mouse models have demonstrated increased excitability and loss of afferent proprioceptive synapses on motor neurons (MNs). To further understand functional changes in the motor neural network occurring in SMA, we studied the intrinsic excitability and synaptic transmission of both MNs and interneurons (INs) from ventral horn in the lumbar spinal cord in the survival motor neuron (SMN)Δ7 mouse model. We found significant differences in the membrane properties of MNs in SMA mice compared to littermate controls, including hyperpolarized resting membrane potential, increased input resistance and decreased membrane capacitance. Action potential (AP) properties in MNs from SMA mice were also different from controls, including decreased rheobase current, increased amplitude and an increased afterdepolarization (ADP) potential. The relationship between AP firing frequency and injected current was reduced in MNs, as was the threshold current, while the percentage of MNs showing long-lasting potentiation (LLP) in the intrinsic excitability was higher in SMA mice. INs showed a high rate of spontaneous firing, and those from SMA mice fired at higher frequency. INs from SMA mice showed little difference in their input-output relationship, threshold current, and plasticity in intrinsic excitability. The changes observed in both passive membrane and AP properties suggest greater overall excitability in both MNs and INs in SMA mice, with MNs showing more differences. There were also changes of synaptic currents in SMA mice. The average charge transfer per post-synaptic current of spontaneous excitatory and inhibitory synaptic currents (sEPSCs/sIPSCs) were lower in SMA MNs, while in INs sIPSC frequency was higher. Strikingly in light of the known loss of excitatory synapses on MNs, there was no difference in sEPSC frequency in MNs from SMA mice compared to controls. For miniature synaptic currents, mEPSC frequency was higher in SMA MNs, while for SMA INs, both mEPSC and mIPSC frequencies were higher. In SMA-affected mice we observed alterations of intrinsic and synaptic properties in both MNs and INs in the spinal motor network that may contribute to the pathophysiology, or alternatively, may be a compensatory response to preserve network function.
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Affiliation(s)
- Jianli Sun
- Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, United States.,Department of Biological Science, Delaware State University, Dover, DE, United States
| | - Melissa A Harrington
- Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, United States.,Department of Biological Science, Delaware State University, Dover, DE, United States
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Ng SY, Manta A, Ljubicic V. Exercise biology of neuromuscular disorders. Appl Physiol Nutr Metab 2018; 43:1194-1206. [DOI: 10.1139/apnm-2018-0229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neuromuscular disorders (NMDs) are chronic conditions that affect the neuromuscular system. Many NMDs currently have no cure; however, as more effective therapies become available for NMD patients, these individuals will exhibit improved health and/or prolonged lifespans. As a result, persons with NMDs will likely desire to engage in a more diverse variety of activities of daily living, including increased physical activity or exercise. Therefore, there is a need to increase our knowledge of the effects of acute exercise and chronic training on the neuromuscular system in NMD contexts. Here, we discuss the disease mechanisms and exercise biology of Duchenne muscular dystrophy (DMD), spinal muscular atrophy (SMA), and myotonic dystrophy type 1 (DM1), which are among the most prevalent NMDs in children and adults. Evidence from clinical and preclinical studies are reviewed, with emphasis on the functional outcomes of exercise, as well as on the putative cellular mechanisms that drive exercise-induced remodelling of the neuromuscular system. Continued investigation of the molecular mechanisms of exercise adaptation in DMD, SMA, and DM1 will assist in enhancing our understanding of the biology of these most prevalent NMDs. This information may also be useful for guiding the development of novel therapeutic targets for future pursuit.
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Affiliation(s)
- Sean Y. Ng
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Alexander Manta
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
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