1
|
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.
Collapse
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
| |
Collapse
|
2
|
Schifino AG, Cooley MA, Zhong RX, Heo J, Hoffman DB, Warren GL, Greising SM, Call JA. Tibial bone strength is negatively affected by volumetric muscle loss injury to the adjacent muscle in male mice. J Orthop Res 2024; 42:123-133. [PMID: 37337074 PMCID: PMC10728344 DOI: 10.1002/jor.25643] [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: 01/10/2023] [Revised: 05/15/2023] [Accepted: 06/03/2023] [Indexed: 06/21/2023]
Abstract
This study's objective was to investigate how contractile strength loss associated with a volumetric muscle loss (VML) injury affects the adjacent tibial bone structural and functional properties in male C57BL/6J mice. Mice were randomized into one of two experimental groups: VML-injured mice that were injured at age 12 weeks and aged to 20 weeks (8 weeks postinjury, VML) and 20-week-old age-matched uninjured mice (Uninjured-20). Tibial bone strength, mid-diaphysis cortical geometry, intrinsic material properties, and metaphyseal trabecular bone structure were assessed by three-point bending and microcomputed tomography (µCT). The plantar flexor muscle group (gastrocnemius, soleus, plantaris) was analyzed for its functional capacities, that is, peak-isometric torque and peak-isokinetic power. VML-injured limbs had 25% less peak-isometric torque and 31% less peak-isokinetic power compared to those of Uninjured-20 mice (p < 0.001). Ultimate load, but not stiffness, was significantly less (10%) in tibias of VML-injured limbs compared to those from Uninjured-20 (p = 0.014). µCT analyses showed cortical bone thickness was 6% less in tibias of VML-injured limbs compared to Uninjured-20 (p = 0.001). Importantly, tibial bone cross-section moment of inertia, the primary determinant of bone ultimate load, was 16% smaller in bones of VML-injured limbs compared to bones from Uninjured-20 (p = 0.046). Metaphyseal trabecular bone structure was also altered up to 23% in tibias of VML-injured limbs (p < 0.010). These changes in tibial bone structure and function after a VML injury occur during a natural maturation phase between the age of 12 and 20 weeks, as evidenced by Uninjured-20 mice having greater tibial bone size and strength compared to uninjured-aged 12-week mice.
Collapse
Affiliation(s)
| | - Marion A. Cooley
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, August University, Augusta, GA USA
| | - Roger X. Zhong
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA USA
| | - Junwon Heo
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA USA
| | | | - Gordon L. Warren
- Department of Physical Therapy, Georgia State University, Atlanta, GA USA
| | | | - Jarrod A. Call
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA USA
| |
Collapse
|
3
|
Brashear SE, Wohlgemuth RP, Hu LY, Jbeily EH, Christiansen BA, Smith LR. Collagen cross-links scale with passive stiffness in dystrophic mouse muscles, but are not altered with administration of a lysyl oxidase inhibitor. PLoS One 2022; 17:e0271776. [PMID: 36302059 PMCID: PMC9612445 DOI: 10.1371/journal.pone.0271776] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/10/2022] [Indexed: 11/19/2022] Open
Abstract
In Duchenne muscular dystrophy (DMD), a lack of functional dystrophin leads to myofiber instability and progressive muscle damage that results in fibrosis. While fibrosis is primarily characterized by an accumulation of extracellular matrix (ECM) components, there are changes in ECM architecture during fibrosis that relate more closely to functional muscle stiffness. One of these architectural changes in dystrophic muscle is collagen cross-linking, which has been shown to increase the passive muscle stiffness in models of fibrosis including the mdx mouse, a model of DMD. We tested whether the intraperitoneal injections of beta-aminopropionitrile (BAPN), an inhibitor of the cross-linking enzyme lysyl oxidase, would reduce collagen cross-linking and passive stiffness in young and adult mdx mice compared to saline-injected controls. We found no significant differences between BAPN treated and saline treated mice in collagen cross-linking and stiffness parameters. However, we observed that while collagen cross-linking and passive stiffness scaled positively in dystrophic muscles, collagen fiber alignment scaled with passive stiffness distinctly between muscles. We also observed that the dystrophic diaphragm showed the most dramatic fibrosis in terms of collagen content, cross-linking, and stiffness. Overall, we show that while BAPN was not effective at reducing collagen cross-linking, the positive association between collagen cross-linking and stiffness in dystrophic muscles still show cross-linking as a viable target for reducing passive muscle stiffness in DMD or other fibrotic muscle conditions.
Collapse
Affiliation(s)
- Sarah E. Brashear
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, California, United States of America
| | - Ross P. Wohlgemuth
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, California, United States of America
| | - Lin-Ya Hu
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, California, United States of America
| | - Elias H. Jbeily
- Department of Orthopaedic Surgery, University of California Davis, Sacramento, California, United States of America
| | - Blaine A. Christiansen
- Department of Orthopaedic Surgery, University of California Davis, Sacramento, California, United States of America
| | - Lucas R. Smith
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, California, United States of America
- Department of Physical Medicine and Rehabilitation, University of California Davis, Sacramento, California, United States of America
- * E-mail:
| |
Collapse
|
4
|
Capitanio D, Moriggi M, Barbacini P, Torretta E, Moroni I, Blasevich F, Morandi L, Mora M, Gelfi C. Molecular Fingerprint of BMD Patients Lacking a Portion in the Rod Domain of Dystrophin. Int J Mol Sci 2022; 23:ijms23052624. [PMID: 35269765 PMCID: PMC8910510 DOI: 10.3390/ijms23052624] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 01/19/2023] Open
Abstract
BMD is characterized by a marked heterogeneity of gene mutations resulting in many abnormal dystrophin proteins with different expression and residual functions. The smaller dystrophin molecules lacking a portion around exon 48 of the rod domain, named the D8 region, are related to milder phenotypes. The study aimed to determine which proteins might contribute to preserving muscle function in these patients. Patients were subdivided, based on the absence or presence of deletions in the D8 region, into two groups, BMD1 and BMD2. Muscle extracts were analyzed by 2-D DIGE, label-free LC-ESI-MS/MS, and Ingenuity pathway analysis (IPA). Increased levels of proteins typical of fast fibers and of proteins involved in the sarcomere reorganization characterize BMD2. IPA of proteomics datasets indicated in BMD2 prevalence of glycolysis and gluconeogenesis and a correct flux through the TCA cycle enabling them to maintain both metabolism and epithelial adherens junction. A 2-D DIGE analysis revealed an increase of acetylated proteoforms of moonlighting proteins aldolase, enolase, and glyceraldehyde-3-phosphate dehydrogenase that can target the nucleus promoting stem cell recruitment and muscle regeneration. In BMD2, immunoblotting indicated higher levels of myogenin and lower levels of PAX7 and SIRT1/2 associated with a set of proteins identified by proteomics as involved in muscle homeostasis maintenance.
Collapse
Affiliation(s)
- Daniele Capitanio
- Department of Biomedical Sciences for Health, University of Milan, 20054 Segrate, Italy; (D.C.); (P.B.)
| | - Manuela Moriggi
- Gastroenterology and Digestive Endoscopy Unit, IRCCS Policlinico San Donato, 20097 Milan, Italy;
| | - Pietro Barbacini
- Department of Biomedical Sciences for Health, University of Milan, 20054 Segrate, Italy; (D.C.); (P.B.)
| | | | - Isabella Moroni
- Child Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
| | - Flavia Blasevich
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy; (F.B.); (L.M.); (M.M.)
| | - Lucia Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy; (F.B.); (L.M.); (M.M.)
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy; (F.B.); (L.M.); (M.M.)
| | - Cecilia Gelfi
- Department of Biomedical Sciences for Health, University of Milan, 20054 Segrate, Italy; (D.C.); (P.B.)
- IRCCS Istituto Ortopedico Galeazzi, 20161 Milan, Italy;
- Correspondence: ; Tel.: +39-025-033-0475
| |
Collapse
|
5
|
Dos Santos JF, Lazzarin MC, Baptista VIDA, Quintana HT, Ribeiro DA, de Oliveira F. Articular cartilage degeneration and bone adaptation due to lack of dystrophin in mice. J Bone Miner Metab 2022; 40:29-39. [PMID: 34549313 DOI: 10.1007/s00774-021-01270-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Duchenne muscular dystrophy is caused by the absence of dystrophin. This study aimed to investigate femoral morphological characteristics of lack of dystrophin in MDX mice, considering that this model, different from DMD patient, is not influenced by corticosteroids administration and limited ambulation. MATERIALS AND METHODS Proximal femur of male 16-week-old Control and MDX mice were submitted to histological, morphometric (volume density of articular cartilage, compact bone, trabecular bone and bone marrow; articular cartilage layers area; articular cartilage cell area), and immunohistochemistry analysis for RUNX-2, RANK-L, MMP-2, MMP-9, Caspase-3 and KI-67. RESULTS MDX showed loss of linearity of articular cartilage with subchondral bone transition and elevation of this subchondral bone to the articular surface when compared with control. In addition, MDX presented morphological difference in the pantographic network of collagen fibers. Volume density of trabecular bone tissue was higher in the MDX than Control, but volume density of articular cartilage was lower in MDX (p < 0.05). The articular cartilage layers and chondrocytes area were significantly smaller in MDX than Control. These results associated to MMPs and osteogenic markers of proximal femur revealed an adaptation process as a consequence of lack of dystrophin. CONCLUSIONS The morphological changes observed in the bone tissue of the MDX may be not only secondary to muscle weakness or chronic use of corticosteroids but also our results indicate connections between decrease of cartilage thickness, collagen network alteration and consequent subchondral changes that may lead to articular cartilage degeneration and bone adaptation mechanism in MDX mice.
Collapse
Affiliation(s)
- José Fontes Dos Santos
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil
| | - Mariana Cruz Lazzarin
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil
| | - Vivianne Izabelle de Araújo Baptista
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil
| | - Hananiah Tardivo Quintana
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil
| | - Daniel Araki Ribeiro
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil
| | - Flavia de Oliveira
- Departamento de Biociências, Universidade Federal de São Paulo (UNIFESP), Rua Silva Jardim, 136 Lab 328, CEP: 11015-020, Santos, SP, 11060-001, Brazil.
| |
Collapse
|
6
|
Hamoudi D, Bouredji Z, Marcadet L, Yagita H, Landry LB, Argaw A, Frenette J. Muscle weakness and selective muscle atrophy in osteoprotegerin-deficient mice. Hum Mol Genet 2021; 29:483-494. [PMID: 31943048 DOI: 10.1093/hmg/ddz312] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/07/2019] [Accepted: 12/07/2019] [Indexed: 01/07/2023] Open
Abstract
Bone and muscle are tightly coupled and form a functional unit under normal conditions. The receptor-activator of nuclear factor κB/receptor-activator of nuclear factor κB ligand/osteoprotegerin (RANK/RANKL/OPG) triad plays a crucial role in bone remodeling. RANKL inhibition by OPG prevents osteoporosis. In contrast, the absence of OPG results in elevated serum RANKL and early onset osteoporosis. However, the impacts of OPG deletion on muscle structure and function are unknown. Our results showed that 1-, 3- and 5-month-old Opg-/- mice have reduced tibial and femoral bone biomechanical properties and higher levels of circulating RANKL. OPG-deficient mice displayed reduced locomotor activity and signs of muscle weakness at 5 months of age. Furthermore, OPG deficiency did not affect the skeletal muscles in 1- and 3-month-old mice. However, it impaired fast-twitch EDL but not slow-twitch Sol muscles in 5-month-old Opg-/- mice. Moreover, 5-month-old Opg-/- mice exhibited selective atrophy of fast-twitch-type IIb myofibers, with increased expression of atrophic proteins such as NF-kB, atrogin-1 and MuRF-1. We used an in vitro model to show that RANKL-stimulated C2C12 myotubes significantly increased the expression of NF-kB, atrogin-1 and MuRF-1. A 2-month anti-RANKL treatment starting at 3 months of age in Opg-/- mice improved voluntary activity, the ex vivo maximum specific force (sP0) of EDL muscles, and whole limb grip force performance and rescued the biomechanical properties of bone. In conclusion, the deletion of OPG and the disruption of the RANKL/OPG balance induced osteoporosis as well as the selective weakness and atrophy of the powerful fast-twitch IIb myofibers, which was partly alleviated by an anti-RANKL treatment.
Collapse
Affiliation(s)
- Dounia Hamoudi
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Zineb Bouredji
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Laetitia Marcadet
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Hideo Yagita
- Department of Immunology, School of Medicine, Juntendo University, Tokyo, Japan
| | - Louis-Bénédict Landry
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Anteneh Argaw
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Jérôme Frenette
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC G1V 4G2, Canada.,Département de Réadaptation, Faculté de Médecine, Université Laval, Quebec City, QC G1V 0A6, Canada
| |
Collapse
|
7
|
Starosta A, Konieczny P. Therapeutic aspects of cell signaling and communication in Duchenne muscular dystrophy. Cell Mol Life Sci 2021; 78:4867-4891. [PMID: 33825942 PMCID: PMC8233280 DOI: 10.1007/s00018-021-03821-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/26/2021] [Accepted: 03/23/2021] [Indexed: 12/11/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating chromosome X-linked disease that manifests predominantly in progressive skeletal muscle wasting and dysfunctions in the heart and diaphragm. Approximately 1/5000 boys and 1/50,000,000 girls suffer from DMD, and to date, the disease is incurable and leads to premature death. This phenotypic severity is due to mutations in the DMD gene, which result in the absence of functional dystrophin protein. Initially, dystrophin was thought to be a force transducer; however, it is now considered an essential component of the dystrophin-associated protein complex (DAPC), viewed as a multicomponent mechanical scaffold and a signal transduction hub. Modulating signal pathway activation or gene expression through epigenetic modifications has emerged at the forefront of therapeutic approaches as either an adjunct or stand-alone strategy. In this review, we propose a broader perspective by considering DMD to be a disease that affects myofibers and muscle stem (satellite) cells, as well as a disorder in which abrogated communication between different cell types occurs. We believe that by taking this systemic view, we can achieve safe and holistic treatments that can restore correct signal transmission and gene expression in diseased DMD tissues.
Collapse
Affiliation(s)
- Alicja Starosta
- Faculty of Biology, Institute of Human Biology and Evolution, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Patryk Konieczny
- Faculty of Biology, Institute of Human Biology and Evolution, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland.
| |
Collapse
|
8
|
Omosule CL, Phillips CL. Deciphering Myostatin's Regulatory, Metabolic, and Developmental Influence in Skeletal Diseases. Front Genet 2021; 12:662908. [PMID: 33854530 PMCID: PMC8039523 DOI: 10.3389/fgene.2021.662908] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/05/2021] [Indexed: 01/08/2023] Open
Abstract
Current research findings in humans and other mammalian and non-mammalian species support the potent regulatory role of myostatin in the morphology and function of muscle as well as cellular differentiation and metabolism, with real-life implications in agricultural meat production and human disease. Myostatin null mice (mstn−/−) exhibit skeletal muscle fiber hyperplasia and hypertrophy whereas myostatin deficiency in larger mammals like sheep and pigs engender muscle fiber hyperplasia. Myostatin’s impact extends beyond muscles, with alterations in myostatin present in the pathophysiology of myocardial infarctions, inflammation, insulin resistance, diabetes, aging, cancer cachexia, and musculoskeletal disease. In this review, we explore myostatin’s role in skeletal integrity and bone cell biology either due to direct biochemical signaling or indirect mechanisms of mechanotransduction. In vitro, myostatin inhibits osteoblast differentiation and stimulates osteoclast activity in a dose-dependent manner. Mice deficient in myostatin also have decreased osteoclast numbers, increased cortical thickness, cortical tissue mineral density in the tibia, and increased vertebral bone mineral density. Further, we explore the implications of these biochemical and biomechanical influences of myostatin signaling in the pathophysiology of human disorders that involve musculoskeletal degeneration. The pharmacological inhibition of myostatin directly or via decoy receptors has revealed improvements in muscle and bone properties in mouse models of osteogenesis imperfecta, osteoporosis, osteoarthritis, Duchenne muscular dystrophy, and diabetes. However, recent disappointing clinical trial outcomes of induced myostatin inhibition in diseases with significant neuromuscular wasting and atrophy reiterate complexity and further need for exploration of the translational application of myostatin inhibition in humans.
Collapse
Affiliation(s)
- Catherine L Omosule
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
| | - Charlotte L Phillips
- Department of Biochemistry, University of Missouri, Columbia, MO, United States.,Department of Child Health, University of Missouri, Columbia, MO, United States
| |
Collapse
|
9
|
Cabelka CA, Baumann CW, Lindsay A, Norton A, Blixt NC, Le G, Warren GL, Mansky KC, Novotny SA, Lowe DA. Tissue selective effects of bazedoxifene on the musculoskeletal system in female mice. J Endocrinol 2021; 248:181-191. [PMID: 33295882 PMCID: PMC7933086 DOI: 10.1530/joe-20-0391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 11/08/2022]
Abstract
The actions of selective estrogen receptor modulators are tissue dependent. The primary objective of the current study was to determine the tissue selective effects of bazedoxifene (BZA) on the musculoskeletal system of ovariectomized (OVX) female mice, focusing on the strengths of muscle-bone pairs in the lower hindlimb. Treatment with BZA after ovariectomy (OVX+BZA) did not prevent body or fat mass gains (P < 0.05). In vivo plantarflexor muscle isometric torque was not affected by treatment with BZA (P = 0.522). Soleus muscle peak isometric, concentric and eccentric tetanic force production were greater in OVX+BZA mice compared to OVX+E2 mice (P ≤ 0.048) with no effect on maximal isometric specific force (P = 0.228). Tibia from OVX+BZA mice had greater cortical cross-sectional area and moment of inertia than OVX mice treated with placebo (P < 0.001), but there was no impact of BZA treatment on cortical bone mineral density, cortical thickness, tibial bone ultimate load or stiffness (P ≥ 0.086). Overall, these results indicate that BZA may be an estrogen receptor agonist in skeletal muscle, as it has previously been shown in bone, providing minor benefits to the musculoskeletal system.
Collapse
Affiliation(s)
- Christine A. Cabelka
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Department of Physical Therapy, The College of St. Scholastica; 940 Woodland Ave, Suite 210, Duluth, MN 55812, USA
| | - Cory W. Baumann
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Angus Lindsay
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota; 420 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Andrew Norton
- Department of Developmental and Surgical Sciences, University of Minnesota; School of Dentistry, Room 16-146 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455, USA
| | - Nick C. Blixt
- Department of Genetics, Cell Biology and Development, University of Minnesota; 6-160 Jackson Hall, 321 Church St.SE, Minneapolis, MN 55455, USA
| | - Gengyun Le
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Gordon L. Warren
- Department of Physical Therapy, Georgia State University; P.O. Box 4019, Atlanta, GA 30302, USA
| | - Kim C. Mansky
- Department of Developmental and Surgical Sciences, University of Minnesota; School of Dentistry, Room 16-146 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455, USA
| | - Susan A. Novotny
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
- Gillette Children’s Specialty Healthcare, 200 University Avenue East, Saint Paul, MN 55101, USA
| | - Dawn A. Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota; MMC 388, 420 Delaware St SE, Minneapolis, MN 55455, USA
| |
Collapse
|
10
|
Robinson JW, Blixt NC, Norton A, Mansky KC, Ye Z, Aparicio C, Wagner BM, Benton AM, Warren GL, Khosla S, Gaddy D, Suva LJ, Potter LR. Male mice with elevated C-type natriuretic peptide-dependent guanylyl cyclase-B activity have increased osteoblasts, bone mass and bone strength. Bone 2020; 135:115320. [PMID: 32179168 DOI: 10.1016/j.bone.2020.115320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/27/2020] [Accepted: 03/12/2020] [Indexed: 02/07/2023]
Abstract
C-type natriuretic peptide (CNP) activation of guanylyl cyclase (GC)-B, also known as NPR2, stimulates cGMP synthesis and bone elongation. CNP activation requires the phosphorylation of multiple GC-B residues and dephosphorylation inactivates the receptor. GC-B7E/7E knockin mice, expressing a glutamate-substituted, "pseudophosphorylated," form of GC-B, exhibit increased CNP-dependent GC activity. Since mutations that constitutively activate GC-B in the absence of CNP result in low bone mineral density in humans, we determined the skeletal phenotype of 9-week old male GC-B7E/7E mice. Unexpectedly, GC-B7E/7E mice have significantly greater tibial and L5 vertebral trabecular bone volume fraction, tibial trabecular number, and tibial bone mineral density. Cortical cross-sectional area, cortical thickness, periosteal diameter and cortical cross-sectional moment of inertia were also significantly increased in GC-B7E/7E tibiae. Three-point bending measurements demonstrated that the mutant tibias and femurs had greater ultimate load, stiffness, energy to ultimate load, and energy to failure. No differences in microhardness indicated similar bone quality at the tissue level between the mutant and wildtype bones. Procollagen 1 N-terminal propeptide and osteocalcin were elevated in serum, and osteoblast number per bone perimeter and osteoid width per bone perimeter were elevated in tibias from the mutant mice. In contrast to mutations that constitutively activate GC-B, we report that mutations that enhance GC-B activity only in the presence of its natural ligand, increase bone mass, bone strength, and the number of active osteoblasts at the bone surface.
Collapse
Affiliation(s)
- Jerid W Robinson
- Departments of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Nicholas C Blixt
- Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Andrew Norton
- Developmental and Surgical Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Kim C Mansky
- Developmental and Surgical Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Zhou Ye
- Restorative Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Conrado Aparicio
- Restorative Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Brandon M Wagner
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Andrew M Benton
- Department of Physical Therapy, Georgia State University, Atlanta, GA, USA
| | - Gordon L Warren
- Department of Physical Therapy, Georgia State University, Atlanta, GA, USA
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Dana Gaddy
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Larry J Suva
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Lincoln R Potter
- Departments of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA; Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.
| |
Collapse
|
11
|
Xiong L, Zhao K, Cao Y, Guo HH, Pan JX, Yang X, Ren X, Mei L, Xiong WC. Linking skeletal muscle aging with osteoporosis by lamin A/C deficiency. PLoS Biol 2020; 18:e3000731. [PMID: 32479501 PMCID: PMC7310860 DOI: 10.1371/journal.pbio.3000731] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 06/23/2020] [Accepted: 05/14/2020] [Indexed: 01/19/2023] Open
Abstract
The nuclear lamina protein lamin A/C is a key component of the nuclear envelope. Mutations in the lamin A/C gene (LMNA) are identified in patients with various types of laminopathy-containing diseases, which have features of accelerated aging and osteoporosis. However, the underlying mechanisms for laminopathy-associated osteoporosis remain largely unclear. Here, we provide evidence that loss of lamin A/C in skeletal muscles, but not osteoblast (OB)-lineage cells, results in not only muscle aging-like deficit but also trabecular bone loss, a feature of osteoporosis. The latter is due in large part to elevated bone resorption. Further cellular studies show an increase of osteoclast (OC) differentiation in cocultures of bone marrow macrophages/monocytes (BMMs) and OBs after treatment with the conditioned medium (CM) from lamin A/C-deficient muscle cells. Antibody array screening analysis of the CM proteins identifies interleukin (IL)-6, whose expression is markedly increased in lamin A/C-deficient muscles. Inhibition of IL-6 by its blocking antibody in BMM-OB cocultures diminishes the increase of osteoclastogenesis. Knockout (KO) of IL-6 in muscle lamin A/C-KO mice diminishes the deficits in trabecular bone mass but not muscle. Further mechanistic studies reveal an elevation of cellular senescence marked by senescence-associated beta-galactosidase (SA-β-gal), p16Ink4a, and p53 in lamin A/C-deficient muscles and C2C12 muscle cells, and the p16Ink4a may induce senescence-associated secretory phenotype (SASP) and IL-6 expression. Taken together, these results suggest a critical role for skeletal muscle lamin A/C to prevent cellular senescence, IL-6 expression, hyperosteoclastogenesis, and trabecular bone loss, uncovering a pathological mechanism underlying the link between muscle aging/senescence and osteoporosis.
Collapse
Affiliation(s)
- Lei Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stoke VA Medical Center, Cleveland, Ohio, United States of America
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Kai Zhao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Yu Cao
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Hao-Han Guo
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jin-Xiu Pan
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stoke VA Medical Center, Cleveland, Ohio, United States of America
| | - Xiao Yang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Xiao Ren
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stoke VA Medical Center, Cleveland, Ohio, United States of America
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Louis Stoke VA Medical Center, Cleveland, Ohio, United States of America
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, United States of America
| |
Collapse
|
12
|
Wood CL, Suchacki KJ, van 't Hof R, Cawthorn WP, Dillon S, Straub V, Wong SC, Ahmed SF, Farquharson C. A comparison of the bone and growth phenotype of mdx, mdx:Cmah-/- and mdx:Utrn +/- murine models with the C57BL/10 wild-type mouse. Dis Model Mech 2020; 13:dmm.040659. [PMID: 31754018 PMCID: PMC6994935 DOI: 10.1242/dmm.040659] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
The muscular dystrophy X-linked (mdx) mouse is commonly used as a mouse model of Duchenne muscular dystrophy (DMD). Its phenotype is, however, mild, and other mouse models have been explored. The mdx:Cmah−/− mouse carries a human-like mutation in the Cmah gene and has a severe muscle phenotype, but its growth and bone development are unknown. In this study, we compared male mdx, mdx:Utrn+/−, mdx:Cmah−/− and wild-type (WT) mice at 3, 5 and 7 weeks of age to determine the suitability of the mdx:Cmah−/− mouse as a model for assessing growth and skeletal development in DMD. The mdx:Cmah−/− mice were lighter than WT mice at 3 weeks, but heavier at 7 weeks, and showed an increased growth rate at 5 weeks. Cortical bone fraction as assessed by micro-computed tomography was greater in both mdx and mdx:Cmah−/− mice versus WT mice at 7 weeks. Tissue mineral density was also higher in mdx:Cmah−/− mice at 3 and 7 weeks. Gene profiling of mdx:Cmah−/− bone identified increased expression of Igf1, Igf1r and Vegfa. Both the mdx and mdx:Cmah−/− mice showed an increased proportion of regulated bone marrow adipose tissue (BMAT) but a reduction in constitutive BMAT. The mdx:Cmah−/− mice show evidence of catch-up growth and more rapid bone development. This pattern does not mimic the typical DMD growth trajectory and therefore the utility of the mdx:Cmah−/− mouse for studying growth and skeletal development in DMD is limited. Further studies of this model may, however, shed light on the phenomenon of catch-up growth. This article has an associated First Person interview with the first author of the paper. Summary: Unlike boys with DMD, the mdx:Cmah−/− mouse shows increased weight gain and more rapid bone development; therefore, its utility for studying growth and skeletal development in DMD is limited.
Collapse
Affiliation(s)
- Claire L Wood
- Division of Developmental Biology, Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, UK .,John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, NE1 3BZ, UK
| | - Karla J Suchacki
- BHF Centre for Cardiovascular Science, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Rob van 't Hof
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Will P Cawthorn
- BHF Centre for Cardiovascular Science, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Scott Dillon
- Division of Developmental Biology, Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, NE1 3BZ, UK
| | - Sze Choong Wong
- Developmental Endocrinology Research Group, School of Medicine, University of Glasgow, Glasgow, G51 4TF, UK
| | - Syed F Ahmed
- Developmental Endocrinology Research Group, School of Medicine, University of Glasgow, Glasgow, G51 4TF, UK
| | - Colin Farquharson
- Division of Developmental Biology, Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, UK
| |
Collapse
|
13
|
Yoon SH, Grynpas MD, Mitchell J. Growth Hormone Increases Bone Toughness and Decreases Muscle Inflammation in Glucocorticoid-Treated Mdx Mice, Model of Duchenne Muscular Dystrophy. J Bone Miner Res 2019; 34:1473-1486. [PMID: 31188496 DOI: 10.1002/jbmr.3718] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/22/2019] [Accepted: 03/01/2019] [Indexed: 01/03/2023]
Abstract
The absence of functional dystrophin with mutations of the dystrophin-encoding gene in Duchenne muscular dystrophy (DMD) results in muscle inflammation and degeneration, as well as bone fragility. Long-term glucocorticoid therapy delays the muscular disease progression but suppresses growth hormone secretion, resulting in short stature and further deleterious effects on bone strength. This study evaluated the therapeutic potential of daily growth hormone therapy in growing mdx mice as a model of DMD. Growth hormone treatment on its own or in combination with glucocorticoids significantly improved muscle histology and function and decreased markers of inflammation in mdx mice. Glucocorticoid treatment thinned cortical bone and decreased bone strength and toughness. Despite the minimal effects of growth hormone on bone microarchitecture, it significantly improved biomechanical properties of femurs and vertebrae, even in the presence of glucocorticoid treatment. Together these studies suggest that the use of growth hormone in DMD should be considered for improvements to muscle and bone health. © 2019 American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, Canada
| | - Marc D Grynpas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, Canada
| | - Jane Mitchell
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| |
Collapse
|
14
|
Hamoudi D, Marcadet L, Piette Boulanger A, Yagita H, Bouredji Z, Argaw A, Frenette J. An anti-RANKL treatment reduces muscle inflammation and dysfunction and strengthens bone in dystrophic mice. Hum Mol Genet 2019; 28:3101-3112. [DOI: 10.1093/hmg/ddz124] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/17/2019] [Accepted: 06/04/2019] [Indexed: 12/20/2022] Open
Abstract
AbstractDuchenne muscular dystrophy (DMD) is the most severe form of muscular dystrophy which leads to progressive muscle degeneration and inflammation. The receptor activator of nuclear factor NF-κB ligand (RANKL) and its receptor (RANK), which are expressed in bone and skeletal and cardiac muscles, form a signaling network upstream from nuclear factor-kappa B (NF-κB). We thus hypothesized that prolonged silencing RANKL/RANK signaling would significantly improve DMD. We showed that RANK and RANKL protein levels were increased in the microenvironment of myofibers of 5-month-old utrophin haploinsufficient mdx (mdx/utrn+/−) mice and that a 4 mg/kg dose of anti-RANKL antibody every 3 d for 28 days is optimal and more effective than 1 mg/kg every 3 d for improving the ex vivo maximum specific force (sP0) of dystrophic EDL muscles from mdx/utrn+/− mice. This functional improvement was associated with a reduction in muscle edema, damage, and fibrosis and a marked reduction in serum CK levels. The anti-RANKL treatment inhibited the NF-κB pathway, increased the proportion of anti-inflammatory and non-cytotoxic M2 macrophages, and reduced the number of centrally-nucleated myofibers and the frequency of small myofibers, suggesting that anti-RANKL inhibits the cycle of degeneration/regeneration in dystrophic mice. A three-point bending test showed that a 28-d anti-RANKL treatment increases the mechanical properties of bone in mdx/utrn+/− dystrophic mice. In conclusion, the anti-RANKL treatment protected against skeletal muscle dysfunctions while enhancing bone mechanical properties, filling two needs with one deed in the context of muscular dystrophy.
Collapse
Affiliation(s)
- Dounia Hamoudi
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
| | - Laetitia Marcadet
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
| | - Antoine Piette Boulanger
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
| | - Hideo Yagita
- Department of Immunology, School of Medicine, Juntendo University, Tokyo, Japan
| | - Zineb Bouredji
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
| | - Anteneh Argaw
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
| | - Jérôme Frenette
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l’ Université Laval (CHUQ-CHUL), Université Laval, Quebec City, QC, Canada
- Département de Réadaptation, Faculté de Médecine, Université Laval, Quebec City, QC, Canada
| |
Collapse
|
15
|
Yoon SH, Grynpas M, Mitchell J. Intermittent PTH treatment improves bone and muscle in glucocorticoid treated Mdx mice: A model of Duchenne Muscular Dystrophy. Bone 2019; 121:232-242. [PMID: 30716510 DOI: 10.1016/j.bone.2019.01.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/21/2019] [Accepted: 01/31/2019] [Indexed: 01/07/2023]
Abstract
Duchenne Muscular Dystrophy (DMD) is a progressive muscle disorder caused by genetic mutations of the dystrophin encoding gene. In the absence of functional dystrophin, DMD patients suffer from muscle inflammation and wasting, as well as compromised bone health with increased risk of fracture. The use of high dose glucocorticoids (GC) as the standard therapy also contributes to bone fragility. This study examined the effects of intermittent, daily administered parathyroid hormone (iPTH), an approved bone anabolic therapy, on growing bone and dystrophic muscle in the presence and absence of prednisone treatment using the Mdx mouse model of DMD. Five-weeks of prednisone treatment in Mdx mice decreased cortical bone thickness and area (p < 0.001), with a large increase in endocortical osteoclasts that were significantly improved by PTH treatment (p < 0.001). GC-induced decreases in cortical bone toughness and modulus were improved with iPTH therapy (p < 0.05). Mdx mice showed significantly less bone mass in trabecular compartments of lumbar vertebrae and iPTH treatment, with or without glucocorticoids, significantly improved structural and material properties of this bone. Prednisone improved grip strength and endurance of treadmill running, which were maintained and further improved, respectively, in co-treated Mdx mice. Altogether, our study demonstrates that iPTH therapy significantly ameliorated GC-induced bone loss and maintained or further enhanced the positive effects of GCs on dystrophic muscle function. These findings give insight into the potential for use of teriparatide to treat growing bone in children with DMD.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, ON, Canada
| | - Marc Grynpas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, ON, Canada
| | - Jane Mitchell
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada.
| |
Collapse
|
16
|
Wong SC, Straub V, Ward LM, Quinlivan R. 236th ENMC International Workshop Bone protective therapy in Duchenne muscular dystrophy: Determining the feasibility and standards of clinical trials Hoofddorp, The Netherlands, 1-3 June 2018. Neuromuscul Disord 2019; 29:251-259. [PMID: 30803852 DOI: 10.1016/j.nmd.2019.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Sze Choong Wong
- Developmental Endocrinology Research Group, Royal Hospital for Children, University of Glasgow, UK.
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Leanne M Ward
- Division of Endocrinology and Metabolism, Children's Hospital of East Ontario, University of Ottawa, Ottawa, Canada
| | - Ros Quinlivan
- MRC Centre for Neuromuscular Disease and Division of Neuropathology, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK
| |
Collapse
|
17
|
|
18
|
Boulanger Piette A, Hamoudi D, Marcadet L, Morin F, Argaw A, Ward L, Frenette J. Targeting the Muscle-Bone Unit: Filling Two Needs with One Deed in the Treatment of Duchenne Muscular Dystrophy. Curr Osteoporos Rep 2018; 16:541-553. [PMID: 30225627 DOI: 10.1007/s11914-018-0468-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW In Duchenne muscular dystrophy (DMD), the progressive skeletal and cardiac muscle dysfunction and degeneration is accompanied by low bone mineral density and bone fragility. Glucocorticoids, which remain the standard of care for patients with DMD, increase the risk of developing osteoporosis. The scope of this review emphasizes the mutual cohesion and common signaling pathways between bone and skeletal muscle in DMD. RECENT FINDINGS The muscle-bone interactions involve bone-derived osteokines, muscle-derived myokines, and dual-origin cytokines that trigger common signaling pathways leading to fibrosis, inflammation, or protein synthesis/degradation. In particular, the triad RANK/RANKL/OPG including receptor activator of NF-kB (RANK), its ligand (RANKL), along with osteoprotegerin (OPG), regulates bone matrix modeling and remodeling pathways and contributes to muscle pathophysiology in DMD. This review discusses the importance of the muscle-bone unit in DMD and covers recent research aimed at determining the muscle-bone interactions that may eventually lead to the development of multifunctional and effective drugs for treating muscle and bone disorders regardless of the underlying genetic mutations in DMD.
Collapse
Affiliation(s)
- Antoine Boulanger Piette
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada
| | - Dounia Hamoudi
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada
| | - Laetitia Marcadet
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada
| | - Françoise Morin
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada
| | - Anteneh Argaw
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada
| | - Leanne Ward
- Division of Endocrinology and Metabolism, Children's Hospital of Eastern Ontario (CHEO), University of Ottawa, Ottawa, ON, K1H 8L1, Canada
| | - Jérôme Frenette
- Centre Hospitalier Universitaire de Québec, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ-CHUL), Axe Neurosciences, Université Laval, Quebec City, QC, G1V 4G2, Canada.
- Département de Réadaptation, Faculté de Médecine, Université Laval, Quebec City, QC, G1V 0A6, Canada.
| |
Collapse
|
19
|
Yoon SH, Sugamori KS, Grynpas MD, Mitchell J. Effect of 25-HydroxyVitamin D Deficiency and Its Interaction with Prednisone Treatment on Musculoskeletal Health in Growing Mdx Mice. Calcif Tissue Int 2018; 103:311-323. [PMID: 29691609 DOI: 10.1007/s00223-018-0423-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/11/2018] [Indexed: 01/28/2023]
Abstract
Duchenne muscular dystrophy (DMD) results from genetic mutations of the gene encoding dystrophin, leading to muscle inflammation and degeneration that is typically treated with glucocorticoids. DMD and its treatment with glucocorticoids result in poor bone health and high risk of fractures. Insufficient levels of 25-hydroxyvitamin D (25-hydroxy D) that may contribute to weakened bone are routinely found in DMD patients. To determine the effect of 25-hydroxy D deficiency, this study examined the effects of low vitamin D dietary intake with and without glucocorticoids on the musculoskeletal system of the Mdx mouse model of DMD. At 10 weeks of age, Mdx mice on control diet had low trabecular bone mineral density of distal femurs and lumbar vertebrae with increased osteoclast numbers compared to wild-type mice. Low vitamin D intake resulted in 25-hydroxy D deficiency but had no effect on trabecular or cortical bone. Cortical bone loss and bone weakness were induced by glucocorticoids while they improved muscle grip strength in Mdx mice. 25-hydroxy D deficiency did not result in any significant effects on growing bone or muscle in the Mdx mice. In combination with glucocorticoid treatment, low 25-hydroxy D resulted in no change in cortical bone mineral density but bone ductility was significantly increased suggesting lower bone mineralization.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, ON, Canada
| | - Kim S Sugamori
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Marc D Grynpas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Health System, Toronto, ON, Canada
| | - Jane Mitchell
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Room 4342, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
20
|
Bott KN, Gittings W, Fajardo VA, Baranowski BJ, Vandenboom R, LeBlanc PJ, Ward WE, Peters SJ. Musculoskeletal structure and function in response to the combined effect of an obesogenic diet and age in male C57BL/6J mice. Mol Nutr Food Res 2017; 61. [PMID: 28556515 DOI: 10.1002/mnfr.201700137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/27/2022]
Abstract
SCOPE The effects of a long-term high fat and sucrose diet (HFS) superimposed with aging on bone and muscle structure and/or function. METHODS AND RESULTS Male C57BL/6J mice (20 weeks of age) were randomized to 1 of 3 groups: baseline (BSL, n = 12), or assigned to a control (AGE, n = 12) or HFS (HFS-AGE, n = 11) diet for 13 weeks. Trabecular bone structure, volumetric bone mineral density (vBMD), and body composition, were measured longitudinally at 20, 24, and 32 weeks of age. In vitro contractile measures were performed on isolated soleus and extensor digitorum longus (EDL) muscles for each group. Both AGE and HFS-AGE had similar declines in trabecular bone structure, while HFS-AGE resulted in increased soleus cross-sectional area (CSA) compared to AGE, but this did not translate to greater twitch or tetanic peak force. The ratio of outcomes of bone to muscle declined in both AGE and HFS-AGE compared to BSL as a result of greater declines in trabecular bone structure than muscle function. CONCLUSION Consumption of a 13-week HFS diet at 20 weeks of age did not exacerbate age-related declines in bone or muscle, but these tissues do not decline in a coordinate manner with greater declines in bone than muscle.
Collapse
Affiliation(s)
- Kirsten N Bott
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - William Gittings
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Val Andrew Fajardo
- Department of Health Sciences & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Bradley J Baranowski
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Rene Vandenboom
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Paul J LeBlanc
- Department of Health Sciences & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Wendy E Ward
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada.,Department of Health Sciences & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| | - Sandra J Peters
- Department of Kinesiology & Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada
| |
Collapse
|
21
|
Mohamad NS, Sinadinos A, Górecki DC, Zioupos P, Tong J. Impact of P2RX7 ablation on the morphological, mechanical and tissue properties of bones in a murine model of duchenne muscular dystrophy. J Biomech 2016; 49:3444-3451. [PMID: 27663621 DOI: 10.1016/j.jbiomech.2016.09.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022]
Abstract
Duchenne muscular dystrophy (DMD) is an inherited, lethal disorder characterised by progressive muscle degeneration and associated bone abnormalities. We have previously demonstrated that P2RX7 purinergic receptors contribute to the pathogenesis of DMD, and found that P2RX7 ablation alleviated the severity of the disease. In this work we have used a dystrophic mdx mouse crossed with the global P2RX7 receptor to generate a knockout mouse (mdx/P2X7-/-), and compared its morphometric, mechanical and tissue properties against those of mdx, as well as the wild type (WT) and the P2RX7 knockout (P2X7-/-). Micro-computed tomography (µCT), three-point bending testing, scanning electron microscopy (SEM) and nano-indentation were utilised in the study. The bones were analysed at approximately 4 weeks of age to examine the impact of P2RX7 ablation on the bone properties during the acute disease phase, before muscle wasting is fully developed. The results show that P2RX7 purinoceptor ablation has produced improvement or significant improvement in some of the morphological, the mechanical and the tissue properties of the dystrophic bones examined. Specifically, although the ablation produced smaller bones with significantly lower total cross-section area (Tt.Ar) and Second Moment of Area (SMA), significantly higher cortical bone area (Ct.Ar), cortical area fraction (Ct.Ar/Tt.Ar) and trabecular bone volume fraction (BV/TV) are found in the mdx/P2X7-/- mice than in any other types. Further, the mdx/P2X7-/- bones have relatively higher average flexural strength, work-to-fracture and significantly higher strain to failure compared with those of mdx, suggesting greater resistance to fracture. Indentation modulus, elasticity and creep are also significantly improved in the knockout cortical bones over those of mdx. These findings seem to suggest that specific pharmacological blockade of P2RX7 may improve dystrophic bones, with a potential for therapeutic application in the treatment of the disease.
Collapse
Affiliation(s)
- N S Mohamad
- Mechanical Behaviour of Materials Group, School of Engineering, University of Portsmouth, UK
| | - A Sinadinos
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
| | - D C Górecki
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
| | - P Zioupos
- Biomechanics Labs, Cranfield Forensic Institute, Cranfield University, UK
| | - J Tong
- Mechanical Behaviour of Materials Group, School of Engineering, University of Portsmouth, UK.
| |
Collapse
|
22
|
Yoon SH, Chen J, Grynpas MD, Mitchell J. Prophylactic pamidronate partially protects from glucocorticoid-induced bone loss in the mdx mouse model of Duchenne muscular dystrophy. Bone 2016; 90:168-80. [PMID: 27373502 DOI: 10.1016/j.bone.2016.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/24/2016] [Accepted: 06/27/2016] [Indexed: 01/19/2023]
Abstract
Glucocorticoids are extensively used to treat patients with Duchenne muscular dystrophy because of their ability to delay muscle damage, prolong ambulation and extend life. However, use of glucocorticoids significantly increases bone loss, fragility and fractures. To determine if antiresorptive bisphosphonates could prevent the effects of glucocorticoids on bone quality, we used dystrophic mdx mice treated with the glucocorticoid prednisone during 8weeks of rapid bone growth from 5 to 13weeks of age and treated some mice with the bisphosphonate pamidronate during the first two weeks of prednisone administration. Prednisone reduced long bone growth, decreased cortical bone thickness and area and decreased the strength of the femurs. Pamidronate treatment protected mice from cortical bone loss but did not increase bone strength. The combination of prednisone and pamidronate inhibited remodeling of metaphyseal trabecular bone with large numbers of trabeculae containing remnants of calcified cartilage. Prednisone improved muscle strength in the mdx mice and decreased serum creatine kinase with evidence of improved muscle histology and these effects were maintained in mice treated with pamidronate.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Jinghan Chen
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Marc D Grynpas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Jane Mitchell
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
| |
Collapse
|
23
|
Huard J, Mu X, Lu A. Evolving paradigms in clinical pharmacology and therapeutics for the treatment of Duchenne muscular dystrophy. Clin Pharmacol Ther 2016; 100:142-6. [DOI: 10.1002/cpt.379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/06/2016] [Indexed: 11/10/2022]
Affiliation(s)
- J Huard
- Department of Orthopedic Surgery, McGovern Medical School; University of Texas Health Science Center at Houston; Houston Texas USA
- Steadman Philippon Research Institute; Vail Colorado USA
- Brown Foundation Institute of Molecular Medicine; Center for Tissue Engineering and Aging Research; Houston Texas USA
| | - X Mu
- Department of Orthopedic Surgery, McGovern Medical School; University of Texas Health Science Center at Houston; Houston Texas USA
- Steadman Philippon Research Institute; Vail Colorado USA
- Brown Foundation Institute of Molecular Medicine; Center for Tissue Engineering and Aging Research; Houston Texas USA
| | - A Lu
- Department of Orthopedic Surgery, McGovern Medical School; University of Texas Health Science Center at Houston; Houston Texas USA
- Steadman Philippon Research Institute; Vail Colorado USA
- Brown Foundation Institute of Molecular Medicine; Center for Tissue Engineering and Aging Research; Houston Texas USA
| |
Collapse
|
24
|
Yoon SH, Sugamori KS, Grynpas MD, Mitchell J. Positive effects of bisphosphonates on bone and muscle in a mouse model of Duchenne muscular dystrophy. Neuromuscul Disord 2015; 26:73-84. [PMID: 26494410 DOI: 10.1016/j.nmd.2015.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 09/25/2015] [Accepted: 09/26/2015] [Indexed: 11/17/2022]
Abstract
Patients with Duchenne muscular dystrophy are at increased risk of decreased bone mineral density and bone fracture as a result of inactivity. To determine if antiresorptive bisphosphonates could improve bone quality and their effects on muscle we studied the Mdx mouse, treated with pamidronate during peak bone growth at 5 and 6 weeks of age, and examined the outcome at 13 weeks of age. Pamidronate increased cortical bone architecture and strength in femurs with increased resistance to fracture. While overall long bone growth was not affected by pamidronate, there was significant inhibition of remodeling in metaphyseal trabecular bone with evidence of residual calcified cartilage. Pamidronate treatment had positive effects on skeletal muscle in the Mdx mice with decreased serum and muscle creatine kinase and evidence of improved muscle histology and grip strength.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada; Canada and Lunenfeld-Tanenbaum Research Institute, Toronto, Ontario, Canada
| | - Kim S Sugamori
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Marc D Grynpas
- Canada and Lunenfeld-Tanenbaum Research Institute, Toronto, Ontario, Canada
| | - Jane Mitchell
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
25
|
Abstract
Aging-induced declines in muscle size and quality are thought to contribute to catabolic alterations in bone, but changes in bone with age also profoundly alter its response to muscle-derived stimuli. This review provides an overview of some of the alterations that occur in muscle and bone with aging, and discusses the cellular and molecular mechanisms that may impact these age-associated changes.
Collapse
Affiliation(s)
- Susan A Novotny
- Orthopedic Research Department, Gillette Children's Specialty Healthcare, Saint Paul, Minnesota;
| | - Gordon L Warren
- Department of Physical Therapy, Georgia State University, Atlanta, Georgia; and
| | - Mark W Hamrick
- Cellular Biology & Anatomy, Georgia Regents University, Augusta, Georgia
| |
Collapse
|
26
|
Mader TL, Novotny SA, Lin AS, Guldberg RE, Lowe DA, Warren GL. CCR2 elimination in mice results in larger and stronger tibial bones but bone loss is not attenuated following ovariectomy or muscle denervation. Calcif Tissue Int 2014; 95:457-66. [PMID: 25234653 PMCID: PMC4228687 DOI: 10.1007/s00223-014-9914-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 09/09/2014] [Indexed: 11/28/2022]
Abstract
Bone loss due to age and disuse contributes to osteoporosis and increases fracture risk. It has been hypothesized that such bone loss can be attenuated by modulation of the C-C chemokine receptor 2 (CCR2) and/or its ligands. The objectives of this study were to examine the effects of genetic elimination of CCR2 on cortical and trabecular bones in the mouse tibia and how bone loss was impacted following disuse and estrogen loss. Female CCR2 knockout (CCR2(-/-)) and wildtype mice underwent ovariectomy (OVX) or denervation of musculature adjacent to the tibia (DEN) to induce bone loss. Cortical and trabecular structural properties as well as mechanical properties (i.e., strength) of tibial bones were measured. Compared to wildtype mice, CCR2(-/-) mice had tibiae that were up to 9% larger and stronger; these differences could be explained mainly by the 17% greater body mass (P < 0.001) of CCR2(-/-) mice. The majority of the tibia's structural and functional responses to OVX and DEN were similar regardless of the lack or presence of CCR2, indicating that CCR2 is not protective against bone loss per se. These findings indicate that while CCR2(-/-) mice do have larger and stronger bones than do wildtype mice, there is minimal evidence that CCR2 elimination provides protection against bone loss during disuse and estrogen loss.
Collapse
Affiliation(s)
- Tara L Mader
- Rehabilitation Science and Program in Physical Therapy, University of Minnesota, Minneapolis, MN, USA,
| | | | | | | | | | | |
Collapse
|
27
|
Low intensity, high frequency vibration training to improve musculoskeletal function in a mouse model of Duchenne muscular dystrophy. PLoS One 2014; 9:e104339. [PMID: 25121503 PMCID: PMC4133244 DOI: 10.1371/journal.pone.0104339] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 07/11/2014] [Indexed: 01/29/2023] Open
Abstract
The objective of the study was to determine if low intensity, high frequency vibration training impacted the musculoskeletal system in a mouse model of Duchenne muscular dystrophy, relative to healthy mice. Three-week old wildtype (n = 26) and mdx mice (n = 22) were randomized to non-vibrated or vibrated (45 Hz and 0.6 g, 15 min/d, 5 d/wk) groups. Invivo and exvivo contractile function of the anterior crural and extensor digitorum longus muscles, respectively, were assessed following 8 wks of vibration. Mdx mice were injected 5 and 1 days prior to sacrifice with Calcein and Xylenol, respectively. Muscles were prepared for histological and triglyceride analyses and subcutaneous and visceral fat pads were excised and weighed. Tibial bones were dissected and analyzed by micro-computed tomography for trabecular morphometry at the metaphysis, and cortical geometry and density at the mid-diaphysis. Three-point bending tests were used to assess cortical bone mechanical properties and a subset of tibiae was processed for dynamic histomorphometry. Vibration training for 8 wks did not alter trabecular morphometry, dynamic histomorphometry, cortical geometry, or mechanical properties (P≥0.34). Vibration did not alter any measure of muscle contractile function (P≥0.12); however the preservation of muscle function and morphology in mdx mice indicates vibration is not deleterious to muscle lacking dystrophin. Vibrated mice had smaller subcutaneous fat pads (P = 0.03) and higher intramuscular triglyceride concentrations (P = 0.03). These data suggest that vibration training at 45 Hz and 0.6 g did not significantly impact the tibial bone and the surrounding musculature, but may influence fat distribution in mice.
Collapse
|
28
|
Abstract
Bone and muscle mass are highly correlated. In part, this is a consequence of both tissues sharing common genetic determinants. In addition, both tissues are responsive to their mechanical environments. New genetic tools in mice will allow genes of interest to be inactivated in experimentally defined contexts, thus allowing investigators to distinguish direct effects on each tissue from physiological responses to a primary phenotype in the other.
Collapse
|
29
|
Abou-Khalil R, Yang F, Mortreux M, Lieu S, Yu YY, Wurmser M, Pereira C, Relaix F, Miclau T, Marcucio RS, Colnot C. Delayed bone regeneration is linked to chronic inflammation in murine muscular dystrophy. J Bone Miner Res 2014; 29:304-15. [PMID: 23857747 PMCID: PMC3893315 DOI: 10.1002/jbmr.2038] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 06/19/2013] [Accepted: 07/01/2013] [Indexed: 12/11/2022]
Abstract
Duchenne muscular dystrophy (DMD) patients exhibit skeletal muscle weakness with continuous cycles of muscle fiber degeneration/regeneration, chronic inflammation, low bone mineral density, and increased risks of fracture. Fragility fractures and associated complications are considered as a consequence of the osteoporotic condition in these patients. Here, we aimed to establish the relationship between muscular dystrophy and fracture healing by assessing bone regeneration in mdx mice, a model of DMD with absence of osteoporosis. Our results illustrate that muscle defects in mdx mice impact the process of bone regeneration at various levels. In mdx fracture calluses, both cartilage and bone deposition were delayed followed by a delay in cartilage and bone remodeling. Vascularization of mdx fracture calluses was also decreased during the early stages of repair. Dystrophic muscles are known to contain elevated numbers of macrophages contributing to muscle degeneration. Accordingly, we observed increased macrophage recruitment in the mdx fracture calluses and abnormal macrophage accumulation throughout the process of bone regeneration. These changes in the inflammatory environment subsequently had an impact on the recruitment of osteoclasts and the remodeling phase of repair. Further damage to the mdx muscles, using a novel model of muscle trauma, amplified both the chronic inflammatory response and the delay in bone regeneration. In addition, PLX3397 treatment of mdx mice, a cFMS (colony stimulating factor receptor 1) inhibitor in monocytes, partially rescued the bone repair defect through increasing cartilage deposition and decreasing the number of macrophages. In conclusion, chronic inflammation in mdx mice contributes to the fracture healing delay and is associated with a decrease in angiogenesis and a transient delay in osteoclast recruitment. By revealing the role of dystrophic muscle in regulating the inflammatory response during bone repair, our results emphasize the implication of muscle in the normal bone repair process and may lead to improved treatment of fragility fractures in DMD patients.
Collapse
Affiliation(s)
- Rana Abou-Khalil
- INSERM U781, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine, Hôpital Necker Enfants Malades, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Novotny SA, Eckhoff MD, Eby BC, Call JA, Nuckley D, Lowe DA. Musculoskeletal response of dystrophic mice to short term, low intensity, high frequency vibration. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2013; 13:418-429. [PMID: 24292612 PMCID: PMC7071346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVES We aimed to identify parameters of low-intensity vibration that initiate the greatest osteogenic response in dystrophin-deficient mice and determine vibration safety for diseased muscle in three separate studies. METHODS Study1: Mdx mice were randomized into seven vibration treatments and 14 d later, plasma osteocalcin and tibial osteogenic gene expression were compared among treatments. Study2: Three days of vibration was compared to other modalities known to elicit muscle injury in mdx mice. Study3: Dystrophic mice with more severe phenotypes due to altered utrophin were subjected to 7 d vibration to determine if muscle injury was induced. Muscle torque and genes associated with inflammation and myogenesis were assessed in Studies 2-3. RESULTS Two sets of parameters (45 Hz 0.6 g and 90 Hz 0.6 g) evoked osteogenic responses. 45 Hz upregulated alkaline phosphatase and tended to upregulate osteoprotegerin without altering RANKL, and 90 Hz simultaneously upregulated osteprotegerin and RANKL. Thus, subsequent muscle studies utilized 45 Hz. Vibration for 3 or 7 d was not injurious to dystrophic muscle as shown by the lack of differences between vibrated and non-vibrated mice in torque and gene expression. CONCLUSIONS Results indicate that vibration at 45 Hz and 0.6 g is safe for dystrophic muscle and may be a therapeutic modality to improve musculoskeletal health in DMD.
Collapse
Affiliation(s)
- S A Novotny
- Department of Kinesiology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | | | | | | |
Collapse
|
31
|
Roderer B, Tsagkari E, Gredes T, Dominiak M, Gedrange T, Kunert-Keil C. WITHDRAWN: Age-dependent muscle dystrophy related changes of craniofacial morphology in mdx mice. Arch Oral Biol 2013:S0003-9969(13)00217-3. [PMID: 23938151 DOI: 10.1016/j.archoralbio.2013.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/04/2013] [Accepted: 07/05/2013] [Indexed: 11/21/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
Collapse
Affiliation(s)
- Beate Roderer
- Department of Orthodontics, Carl Gustav Carus Campus, Technische Universität Dresden, Fetscherstr. 74, D-01307 Dresden, Germany
| | | | | | | | | | | |
Collapse
|
32
|
Isaac C, Wright A, Usas A, Li H, Tang Y, Mu X, Greco N, Dong Q, Vo N, Kang J, Wang B, Huard J. Dystrophin and utrophin "double knockout" dystrophic mice exhibit a spectrum of degenerative musculoskeletal abnormalities. J Orthop Res 2013; 31:343-9. [PMID: 23097179 PMCID: PMC4108902 DOI: 10.1002/jor.22236] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 08/28/2012] [Indexed: 02/04/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a degenerative muscle disorder characterized by the lack of dystrophin expression at the sarcolemma of muscle fibers. In addition, DMD patients acquire osteopenia, fragility fractures, and scoliosis indicating that a deficiency in skeletal homeostasis coexists but little is known about the effects of DMD on bone and other connective tissues within the musculoskeletal system. Recent evidence has emerged implicating adult stem cell dysfunction in DMD myopathogenesis. Given the common mesenchymal origin of muscle and bone, we sought to investigate bone and other musculoskeletal tissues in a DMD mouse model. Here, we report that dystrophin-utrophin double knockout (dko) mice exhibit a spectrum of degenerative changes, outside skeletal muscle, in bone, articular cartilage, and intervertebral discs, in addition to reduced lifespan, muscle degeneration, spinal deformity, and cardiomyopathy previously reported. We also report these mice to have a reduced capacity for bone healing and exhibit spontaneous heterotopic ossification in the hind limb muscles. Therefore, we propose the dko mouse as a model for premature musculoskeletal aging and posit that a similar phenomenon may occur in patients with DMD.
Collapse
Affiliation(s)
- Christian Isaac
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219,Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Adam Wright
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219,Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Arvydas Usas
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219
| | - Hongshuai Li
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219
| | - Ying Tang
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219
| | - Xiaodong Mu
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219
| | - Nicholas Greco
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219,Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Qing Dong
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Nam Vo
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - James Kang
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Bing Wang
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219,Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Johnny Huard
- Stem Cell Research Center, Bridgeside Point II, 450 Technology Dr, Suite 206, Pittsburgh, Pennsylvania 15219,Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| |
Collapse
|
33
|
Gray SK, McGee-Lawrence ME, Sanders JL, Condon KW, Tsai CJ, Donahue SW. Black bear parathyroid hormone has greater anabolic effects on trabecular bone in dystrophin-deficient mice than in wild type mice. Bone 2012; 51:578-85. [PMID: 22584007 PMCID: PMC3412940 DOI: 10.1016/j.bone.2012.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 05/03/2012] [Accepted: 05/04/2012] [Indexed: 12/12/2022]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease that has deleterious consequences in muscle and bone, leading to decreased mobility, progressive osteoporosis, and premature death. Patients with DMD experience a higher-than-average fracture rate, particularly in the proximal and distal femur and proximal tibia. The dystrophin-deficient mdx mouse is a model of DMD that demonstrates muscle degeneration and fibrosis and osteoporosis. Parathyroid hormone, an effective anabolic agent for post-menopausal and glucocorticoid-induced osteoporosis, has not been explored for DMD. Black bear parathyroid hormone (bbPTH) has been implicated in the maintenance of bone properties during extended periods of disuse (hibernation). We cloned bbPTH and found 9 amino acid residue differences from human PTH. Apoptosis was mitigated and cAMP was activated by bbPTH in osteoblast cultures. We administered 28nmol/kg of bbPTH 1-84 to 4-week old male mdx and wild type mice via daily (5×/week) subcutaneous injection for 6 weeks. Vehicle-treated mdx mice had 44% lower trabecular bone volume fraction than wild type mice. No changes were found in femoral cortical bone geometry or mechanical properties with bbPTH treatment in wild type mice, and only medio-lateral moment of inertia changed with bbPTH treatment in mdx femurs. However, μCT analyses of the trabecular regions of the distal femur and proximal tibia showed marked increases in bone volume fraction with bbPTH treatment, with a greater anabolic response (7-fold increase) in mdx mice than wild type mice (2-fold increase). Trabecular number increased in mdx long bone, but not wild type bone. Additionally, greater osteoblast area and decreased osteoclast area were observed with bbPTH treatment in mdx mice. The heightened response to PTH in mdx bone compared to wild type suggests a link between dystrophin deficiency, altered calcium signaling, and bone. These findings support further investigation of PTH as an anabolic treatment for DMD-induced osteoporosis.
Collapse
Affiliation(s)
- Sarah K Gray
- Michigan Tech University, Dept. of Biomedical Engineering, 309 M&M Bldg., 1400 Townsend Dr., Houghton, MI 49931, USA
| | | | | | | | | | | |
Collapse
|
34
|
Karasik D, Cohen-Zinder M. The genetic pleiotropy of musculoskeletal aging. Front Physiol 2012; 3:303. [PMID: 22934054 PMCID: PMC3429074 DOI: 10.3389/fphys.2012.00303] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 07/11/2012] [Indexed: 12/30/2022] Open
Abstract
Musculoskeletal aging is detrimental to multiple bodily functions and starts early, probably in the fourth decade of an individual's life. Sarcopenia is a health problem that is expected to only increase as a greater portion of the population lives longer; prevalence of the related musculoskeletal diseases is similarly expected to increase. Unraveling the biological and biomechanical associations and molecular mechanisms underlying these diseases represents a formidable challenge. There are two major problems making disentangling the biological complexity of musculoskeletal aging difficult: (a) it is a systemic, rather than "compartmental," problem, which should be approached accordingly, and (b) the aging per se is neither well defined nor reliably measurable. A unique challenge of studying any age-related condition is a need of distinguishing between the "norm" and "pathology," which are interwoven throughout the aging organism. We argue that detecting genes with pleiotropic functions in musculoskeletal aging is needed to provide insights into the potential biological mechanisms underlying inter-individual differences insusceptibility to the musculoskeletal diseases. However, exploring pleiotropic relationships among the system's components is challenging both methodologically and conceptually. We aimed to focus on genetic aspects of the cross-talk between muscle and its "neighboring" tissues and organs (tendon, bone, and cartilage), and to explore the role of genetics to find the new molecular links between skeletal muscle and other parts of the "musculoskeleton." Identification of significant genetic variants underlying the musculoskeletal system's aging is now possible more than ever due to the currently available advanced genomic technologies. In summary, a "holistic" genetic approach is needed to study the systems's normal functioning and the disease predisposition in order to improve musculoskeletal health.
Collapse
Affiliation(s)
- David Karasik
- Faculty of Medicine in the Galilee, Bar-Ilan University Safed, Israel
| | | |
Collapse
|
35
|
Osteoporosis genetics: year 2011 in review. BONEKEY REPORTS 2012; 1:114. [PMID: 23951496 DOI: 10.1038/bonekey.2012.114] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 05/09/2012] [Indexed: 02/08/2023]
Abstract
Increased rates of osteoporotic fractures represent a worldwide phenomenon, which result from a progressing aging in the population around the world and creating socioeconomic problems. This review will focus mostly on human genetic studies identifying genomic regions, genes and mutations associated with osteoporosis (bone mineral density (BMD) and bone loss) and related fractures, which were published during 2011. Although multiple genome-wide association studies (GWAS) were performed to date, the genetic cause of osteoporosis and fractures has not yet been found, and only a small fraction of high heritability of bone mass was successfully explained. GWAS is a successful tool to initially define and prioritize specific chromosomal regions showing associations with the desired traits or diseases. Following the initial discovery and replication, targeted sequencing is needed in order to detect those rare variants which GWAS does not reveal by design. Recent GWAS findings for BMD included WNT16 and MEF2C. The role of bone morphogenetic proteins in fracture healing has been explored by several groups, and new single-nucleotide polymorphisms present in genes such as NOGGIN and SMAD6 were found to be associated with a greater risk of fracture non-union. Finding new candidate genes, and mutations associated with BMD and fractures, also provided new biological connections. Thus, candidates for molecular link between bone metabolism and lactation (for example, RAP1A gene), as well as possible pleiotropic effects for bone and muscle (ACTN3 gene) were suggested. The focus of contemporary studies seems to move toward whole-genome sequencing, epigenetic and functional genomics strategies to find causal variants for osteoporosis.
Collapse
|
36
|
Novotny SA, Warren GL, Lin AS, Guldberg RE, Baltgalvis KA, Lowe DA. Prednisolone treatment and restricted physical activity further compromise bone of mdx mice. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2012; 12:16-23. [PMID: 22373947 PMCID: PMC3366630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVES The purpose of this study was to determine the extent to which prednisolone treatment and restricted physical activity caused deleterious changes in inherently compromised mdx bone. METHODS Four week-old male mdx mice (n=36) were treated for 8-wk either with or without prednisolone (0.8-1.3 mg/kg/d) and were housed in traditional or small cages (restricted activity). Tibial bone strength, geometry, and intrinsic material properties were assessed at the mid-shaft by three-point bending and micro-computed tomography (μCT). RESULTS Three-point bending results showed that both prednisolone and restricted activity reduced bone strength (7%), however stiffness was only reduced in restricted-activity mice. μCT analyses showed that cortical bone area and cortical thickness were 13% smaller in restricted-activity mice, and may have accounted for their compromised bone strength. Intrinsic material properties, including volumetric bone mineral density (vBMD) and modulus of elasticity, were not impacted by either treatment, however, vBMD tended to be lower in restricted-activity mice (p=0.06). CONCLUSIONS These data show that prednisolone treatment and restricted physical activity independently accentuate reductions in the strength and geometry of mdx bone, but do not influence intrinsic material properties.
Collapse
Affiliation(s)
- S A Novotny
- Department of Kinesiology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | | | | | | | | | | |
Collapse
|
37
|
Morgenroth VH, Hache LP, Clemens PR. Insights into bone health in Duchenne muscular dystrophy. BONEKEY REPORTS 2012; 1:9. [PMID: 23951421 DOI: 10.1038/bonekey.2012.5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 11/05/2011] [Indexed: 12/22/2022]
Abstract
Poor bone health is a significant problem for patients with Duchenne muscular dystrophy (DMD), a progressive, disabling disease. Although the primary focus of DMD disease pathogenesis is degeneration of striated muscle, impairment of bone health likely has a role in the disease that has only been superficially examined to date. Deficiency of bone mineral density and increased incidence of bone fractures are well-recognized clinical components of the DMD phenotype. Furthermore, therapy with corticosteroids, an approved treatment for DMD that prolongs ambulation, may have multiple effects on bone health in DMD patients. This review examines the evidence in preclinical models and in human DMD disease that provides insight into the role performed by bone in the disease pathogenesis and phenotype of DMD. The information reviewed here points toward the need for mechanistic and therapeutic studies to optimize bone health in DMD patients.
Collapse
|
38
|
Nakagaki WR, Camilli JA. Spontaneous Healing Capacity of Calvarial Bone Defects in mdx Mice. Anat Rec (Hoboken) 2012; 295:590-6. [DOI: 10.1002/ar.22412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 12/20/2011] [Indexed: 11/09/2022]
|
39
|
Nakagaki WR, Camilli JA. Bone tissue and muscle dystrophin deficiency in mdx mice. Joint Bone Spine 2011; 79:129-33. [PMID: 22079415 DOI: 10.1016/j.jbspin.2011.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 08/08/2011] [Indexed: 01/06/2023]
Abstract
Duchenne muscular dystrophy is a neuromuscular disease caused by the lack of dystrophin that affects skeletal muscles, causing degeneration of muscle fibers and replacing them with fibrous and adipose tissue, events that gradually lead to functional loss. Patients with Duchenne muscular dystrophy have shown that bones become more fragile with age and with advancement of the disease. Muscle weakness and reduced mobility have been suggested to be the factors that promote bone deterioration. However, it seems that this does not occur in mdx mice. It has been identified in mdx mice the existence of a factor related or not to the lack of dystrophin that also participates in the impairment of bone quality. Mdx mice also exhibit muscle degeneration, but unlike human, it is compensated by muscle regeneration. In consequence, there is an increase in the muscle mass, but not necessarily of muscle contractile strength. The accommodation of this increased muscle mass promotes bone formation at specific sites, such as at tendo-osseous junctions. In addition, the inflammatory response to muscle injury may be responsible for the increase in angiogenesis and regeneration observed in mdx mice, inducing the release of cytokines and chemokines that play an important role in the recruitment of leukocytes and macrophages. Then, mdx mice may possess compensatory mechanisms in bone in response to a genetic defect.
Collapse
Affiliation(s)
- Wilson Romero Nakagaki
- Department of Anatomy, Cell Biology and Physiology and Biophysics, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | | |
Collapse
|