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Swiderski K, Chan AS, Herold MJ, Kueh AJ, Chung JD, Hardee JP, Trieu J, Chee A, Naim T, Gregorevic P, Lynch GS. The BALB/c.mdx62 mouse exhibits a dystrophic muscle pathology and is a model of Duchenne muscular dystrophy. Dis Model Mech 2024; 17:dmm050502. [PMID: 38602028 PMCID: PMC11095634 DOI: 10.1242/dmm.050502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating monogenic skeletal muscle-wasting disorder. Although many pharmacological and genetic interventions have been reported in preclinical studies, few have progressed to clinical trials with meaningful benefit. Identifying therapeutic potential can be limited by availability of suitable preclinical mouse models. More rigorous testing across models with varied background strains and mutations can identify treatments for clinical success. Here, we report the generation of a DMD mouse model with a CRISPR-induced deletion within exon 62 of the dystrophin gene (Dmd) and the first generated in BALB/c mice. Analysis of mice at 3, 6 and 12 months of age confirmed loss of expression of the dystrophin protein isoform Dp427 and resultant dystrophic pathology in limb muscles and the diaphragm, with evidence of centrally nucleated fibers, increased inflammatory markers and fibrosis, progressive decline in muscle function, and compromised trabecular bone development. The BALB/c.mdx62 mouse is a novel model of DMD with associated variations in the immune response and muscle phenotype, compared with those of existing models. It represents an important addition to the preclinical model toolbox for developing therapeutic strategies.
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Affiliation(s)
- Kristy Swiderski
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Audrey S. Chan
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marco J. Herold
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3052, Australia
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia
- School of Cancer Medicine, La Trobe University, Heidelberg, VIC 3084, Australia
| | - Andrew J. Kueh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3052, Australia
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia
- School of Cancer Medicine, La Trobe University, Heidelberg, VIC 3084, Australia
| | - Jin D. Chung
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Justin P. Hardee
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jennifer Trieu
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Annabel Chee
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Timur Naim
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Paul Gregorevic
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Gordon S. Lynch
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC 3010, Australia
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Tung JYL, Chow TK, Wai M, Lo J, Chan SHS. Bone Health Status of Children with Spinal Muscular Atrophy. J Bone Metab 2023; 30:319-327. [PMID: 38073265 PMCID: PMC10721381 DOI: 10.11005/jbm.2023.30.4.319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a group of rare, inherited neuromuscular disorders. Bone health is often a neglected issue in children with SMA. This study aimed to evaluate the bone health status of children with SMA in Hong Kong. METHODS This retrospective study included children with SMA who were managed in the Neuromuscular Disorder Clinics of 2 quaternary centers in Hong Kong. Bone health status was assessed by fracture history, bone mineral density (BMD) measured by dual energy X-ray absorptiometry, and serum 25-hydroxy-vitamin D (25[OH]D) level. RESULTS Thirty-two children were included (males, 12). The median age was 10.8 years. BMD assessments were performed in 17 patients (SMA type 1=2, type 2=8, type 3=7). Low BMD was observed in 16 out of 17 patients. Four had a history of long bone fractures and were started on bisphosphonates. SMA types, age at last visit, sex, ambulation, and 25(OH)D level were not associated with fracture history or BMD Z-scores. Only one fulfilled the 2019 International Society for Clinical Densitometry (ISCD) pediatric definition of osteoporosis, with both low BMD and a history of clinically significant fracture. CONCLUSIONS Children with SMA on disease-modifying treatments commonly had Low BMD and a history of fractures, but osteoporosis was uncommon according to the 2019 ISCD pediatric definition. A special definition of osteoporosis may be needed for this high-risk group.
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Affiliation(s)
- Joanna Yuet-Ling Tung
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children’s Hospital, Hong Kong SAR,
China
| | - Tsz-Kit Chow
- Nuclear Medicine Unit, Department of Radiology, Queen Mary Hospital, Hong Kong SAR,
China
| | - Monique Wai
- Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR,
China
| | - Jasmine Lo
- Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR,
China
| | - Sophelia Hoi Shan Chan
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children’s Hospital, Hong Kong SAR,
China
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR,
China
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Obara H, Tajima T, Tsukamoto M, Yamanaka Y, Suzuki H, Zenke Y, Kawasaki M, Kouzaki K, Nakazato K, Hiranuma K, Sakai A. Trabecular Bone Volume Is Reduced, With Deteriorated Microstructure, With Aging in a Rat Model of Duchenne Muscular Dystrophy. J UOEH 2022; 44:323-330. [PMID: 36464306 DOI: 10.7888/juoeh.44.323] [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] [Indexed: 06/17/2023]
Abstract
We aimed to clarify the effect of aging on trabecular bone volume and trabecular bone microstructure in a rat model of Duchenne muscular dystrophy (DMD). Six rats each of wild type (WT) and DMD model at 15 weeks of age, and 4 rats each at 30 weeks of age, were analyzed by dual energy X-ray absorptiometry and by micro-CT for analysis of trabecular and cortical bone of the femur. Bone mineral density was significantly lower in the DMD group than in the WT group at both 15 and 30 weeks of age. Micro-CT showed that trabecular bone volume and number were not significantly different between the two groups at 15 weeks, but at 30 weeks both were significantly lower in the DMD group than in the WT group. Connectivity density and structure model index were not significantly different between the two groups at 15 weeks, but at 30 weeks they differed significantly. No significant differences between the WT and DMD groups in cortical thickness and cortical area were evident at both 15 and 30 weeks. In conclusion, trabecular bone volume is significantly reduced, with deteriorated microstructure, with aging in a rat model of DMD.
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Affiliation(s)
- Hinako Obara
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Takafumi Tajima
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Manabu Tsukamoto
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Yoshiaki Yamanaka
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Hitoshi Suzuki
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Yukichi Zenke
- Department of Emergency Medicine, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Makoto Kawasaki
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Karina Kouzaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, Japan. Setagaya-ku, Tokyo 158-8508, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Japan. Setagaya-ku, Tokyo 158-8508, Japan
| | - Kenji Hiranuma
- Graduate School of Health and Sport Science, Nippon Sport Science University, Japan. Setagaya-ku, Tokyo 158-8508, Japan
| | - Akinori Sakai
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan
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Crabtree NJ, Roper H, Shaw NJ. Cessation of ambulation results in a dramatic loss of trabecular bone density in boys with Duchenne muscular dystrophy (DMD). Bone 2022; 154:116248. [PMID: 34718220 DOI: 10.1016/j.bone.2021.116248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/12/2021] [Accepted: 10/26/2021] [Indexed: 11/02/2022]
Abstract
Glucocorticoids are currently used to improve muscle strength and prolong ambulation in boys with DMD although the effect on bone health is still unclear. The aim of this study was to compare bone strength in healthy children and boys with DMD and investigate the interaction between diminished muscle function, loss of ambulation and high dose oral steroids, over a two year time frame. Fifty children were studied, 14 healthy boys (HB), 13 boys with DMD who remained ambulant (DMD-RA) and 23 boys with DMD who lost ambulation (DMD-LA). All boys with DMD had taken oral glucocorticoids. Peripheral quantitative computed tomography was used to measure bone geometry, density, strength and muscle mass of the non-dominant tibia and radius. Measurements were made at baseline, 12 and 24 months at the distal metaphysis and mid diaphysis sites. Differences between the three groups were evaluated using ANOVA and a repeated measures model. There were no significant differences in age between the groups: mean age was 9.4, 8.7 and 8.8 years for HB, DMD-RA and DMD-LA, respectively. There was no significant difference in steroid exposure between the DMD groups. However, boys who lost ambulation had significantly lower muscle function at baseline (North Star Ambulatory Assessment DMD-RA 23.6 vs. DMD-LA 18.8; p < 0.05). At baseline, healthy boys had significantly greater trabecular bone density at the distal radius /ulna (23%/27%) and distal tibia/fibula (30%/46%) than boys with DMD (p < 0.05). They also had significantly larger diaphyseal tibiae/fibulae (74%/36%) and radii/ulnae (49%/31%) with thicker corticies and consequently greater bone strength. In contrast, boys with DMD had greater cortical density (4%). Over time, there were small significant differences in the rate of change of both muscle and bone parameters between healthy boys and boys with DMD. For both ambulant and non-ambulant boys with DMD the greatest changes in cortical bone were evident at the tibia. After two years boys with DMD had on average, 63% less bone strength than healthy boys. However, the most strikingly significant difference was in trabecular bone density for boys who became non-ambulant. By 2 years non-ambulant DMD boys had 53% less trabecular bone density at distal tibia than their healthy age matched peers compared with boys who remained ambulant who had 27% less trabecular bone density. In conclusion, bone and muscle strength is reduced for all boys with DMD even while they remain ambulant. However, tibia trabecular bone density loss is significantly accelerated in DMD boys who lose independent ambulation compared to DMD boys who remain ambulant despite equivalent levels of corticosteroid exposure.
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Affiliation(s)
- N J Crabtree
- Department of Endocrinology and Diabetes, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK; Department of Paediatrics, Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
| | - H Roper
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - N J Shaw
- Department of Endocrinology and Diabetes, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK; Department of Paediatrics, Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
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