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Tan BB, Schwartz NE, Copes LE, Garland T. Effects of long-term voluntary wheel running and selective breeding for wheel running on femoral nutrient canals. J Anat 2024; 244:1015-1029. [PMID: 38303650 PMCID: PMC11095308 DOI: 10.1111/joa.14021] [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: 10/10/2023] [Revised: 01/15/2024] [Accepted: 01/19/2024] [Indexed: 02/03/2024] Open
Abstract
The nutrient artery provides ~50%-70% of the total blood volume to long bones in mammals. Studying the functional characteristics of this artery in vivo can be difficult and expensive, so most researchers have measured the nutrient foramen, an opening on the outer surface of the bone that served as the entry point for the nutrient artery during development and bone ossification. Others have measured the nutrient canal (i.e., the passage which the nutrient artery once occupied), given that the external dimensions of the foramen do not necessarily remain uniform from the periosteal surface to the medullary cavity. The nutrient canal, as an indicator of blood flow to long bones, has been proposed to provide a link to studying organismal activity (e.g., locomotor behavior) from skeletal morphology. However, although external loading from movement and activity causes skeletal remodeling, it is unclear whether it affects the size or configuration of nutrient canals. To investigate whether nutrient canals can exhibit phenotypic plasticity in response to physical activity, we studied a mouse model in which four replicate high runner (HR) lines have been selectively bred for high voluntary wheel-running behavior. The selection criterion is the average number of wheel revolutions on days 5 and 6 of a 6-day period of wheel access as young adults (~6-8 weeks old). An additional four lines are bred without selection to serve as controls (C). For this study, 100 female mice (half HR, half C) from generation 57 were split into an active group housed with wheels and a sedentary group housed without wheels for 12 weeks starting at ~24 days of age. Femurs were collected, soft tissues were removed, and femora were micro-computed tomography scanned at a resolution of 12 μm. We then imported these scans into AMIRA and created 3D models of femoral nutrient canals. We tested for evolved differences in various nutrient canal traits between HR and C mice, plastic changes resulting from chronic exercise, and the selection history-by-exercise interaction. We found few differences between the nutrient canals of HR versus C mice, or between the active and sedentary groups. We did find an interaction between selection history and voluntary exercise for the total number of nutrient canals per femur, in which wheel access increased the number of canals in C mice but decreased it in HR mice. Our results do not match those from an earlier study, conducted at generation 11, which was prior to the HR lines reaching selection limits for wheel running. The previous study found that mice from the HR lines had significantly larger total canal cross-sectional areas compared to those from C lines. However, this discrepancy is consistent with studies of other skeletal traits, which have found differences between HR and C mice to be somewhat inconsistent across generations, including the loss of some apparent adaptations with continued selective breeding after reaching a selection limit for wheel-running behavior.
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Affiliation(s)
- Brandon B Tan
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, California, USA
| | - Nicole E Schwartz
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, California, USA
| | - Lynn E Copes
- Department of Medical Sciences, Frank H. Netter MD School of Medicine, Quinnipiac University, Hamden, Connecticut, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, California, USA
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2
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Bone adaptation and osteoporosis prevention in hibernating mammals. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111411. [PMID: 36871815 DOI: 10.1016/j.cbpa.2023.111411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023]
Abstract
Hibernating bears and rodents have evolved mechanisms to prevent disuse osteoporosis during the prolonged physical inactivity that occurs during hibernation. Serum markers and histological indices of bone remodeling in bears indicate reduced bone turnover during hibernation, which is consistent with organismal energy conservation. Calcium homeostasis is maintained by balanced bone resorption and formation since hibernating bears do not eat, drink, urinate, or defecate. Reduced and balanced bone remodeling protect bear bone structure and strength during hibernation, unlike the disuse osteoporosis that occurs in humans and other animals during prolonged physical inactivity. Conversely, some hibernating rodents show varying degrees of bone loss such as osteocytic osteolysis, trabecular loss, and cortical thinning. However, no negative effects of hibernation on bone strength in rodents have been found. More than 5000 genes in bear bone tissue are differentially expressed during hibernation, highlighting the complexity of hibernation induced changes in bone. A complete picture of the mechanisms that regulate bone metabolism in hibernators still alludes us, but existing data suggest a role for endocrine and paracrine factors such as cocaine- and amphetamine-regulated transcript (CART) and endocannabinoid ligands like 2-arachidonoyl glycerol (2-AG) in decreasing bone remodeling during hibernation. Hibernating bears and rodents evolved the capacity to preserve bone strength during long periods of physical inactivity, which contributes to their survival and propagation by allowing physically activity (foraging, escaping predators, and mating) without risk of bone fracture following hibernation. Understanding the biological mechanisms regulating bone metabolism in hibernators may inform novel treatment strategies for osteoporosis in humans.
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3
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Buettmann EG, Goldscheitter GM, Hoppock GA, Friedman MA, Suva LJ, Donahue HJ. Similarities Between Disuse and Age-Induced Bone Loss. J Bone Miner Res 2022; 37:1417-1434. [PMID: 35773785 PMCID: PMC9378610 DOI: 10.1002/jbmr.4643] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 11/07/2022]
Abstract
Disuse and aging are known risk factors associated with low bone mass and quality deterioration, resulting in increased fracture risk. Indeed, current and emerging evidence implicate a large number of shared skeletal manifestations between disuse and aging scenarios. This review provides a detailed overview of current preclinical models of musculoskeletal disuse and the clinical scenarios they seek to recapitulate. We also explore and summarize the major similarities between bone loss after extreme disuse and advanced aging at multiple length scales, including at the organ/tissue, cellular, and molecular level. Specifically, shared structural and material alterations of bone loss are presented between disuse and aging, including preferential loss of bone at cancellous sites, cortical thinning, and loss of bone strength due to enhanced fragility. At the cellular level bone loss is accompanied, during disuse and aging, by increased bone resorption, decreased formation, and enhanced adipogenesis due to altered gap junction intercellular communication, WNT/β-catenin and RANKL/OPG signaling. Major differences between extreme short-term disuse and aging are discussed, including anatomical specificity, differences in bone turnover rates, periosteal modeling, and the influence of subject sex and genetic variability. The examination also identifies potential shared mechanisms underlying bone loss in aging and disuse that warrant further study such as collagen cross-linking, advanced glycation end products/receptor for advanced glycation end products (AGE-RAGE) signaling, reactive oxygen species (ROS) and nuclear factor κB (NF-κB) signaling, cellular senescence, and altered lacunar-canalicular connectivity (mechanosensation). Understanding the shared structural alterations, changes in bone cell function, and molecular mechanisms common to both extreme disuse and aging are paramount to discovering therapies to combat both age-related and disuse-induced osteoporosis. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Evan G Buettmann
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Galen M Goldscheitter
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Gabriel A Hoppock
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Michael A Friedman
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Larry J Suva
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Henry J Donahue
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
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4
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A mouse model of disuse osteoporosis based on a movable noninvasive 3D-printed unloading device. J Orthop Translat 2022; 33:1-12. [PMID: 35070713 PMCID: PMC8753063 DOI: 10.1016/j.jot.2021.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/02/2021] [Accepted: 11/22/2021] [Indexed: 01/16/2023] Open
Abstract
Objective Disuse osteoporosis is a major type of bone loss disease characterized by regional bone loss and microstructure alterations. The condition is induced by a marked decrease in weight bearing over time, which usually occurs due to limb immobilization, therapeutic bed rest or space flight. To date, the most commonly used mouse model of disuse osteoporosis is constructed using the classical tail suspension method, which causes tail injury, movement inconvenience and mental stress. This study aimed to propose a noninvasive and effective method for the establishment of a mouse model of disuse osteoporosis and compared this method with the tail suspension method. Methods 3D printing technology was applied to construct a movable unloading device. A movable noninvasive 3D-printed unloading device (3D-ULD) was used to unload the hindlimbs of the mice. The bone microstructure and bone volume of unloaded femurs were analysed through micro-CT and H&E staining, and von Kossa staining was performed for the detection of bone mineralization in the femurs. TRAP staining, IHC-CTSK and Q-PCR were performed for evaluation of the bone resorption ability, and double labelling, IHC-DMP1, ALP staining and Q-PCR assays were conducted to assess the osteogenic ability. The mechanical properties of disused bone were detected using the three-point bending test. The body, thymus and spleen weights of the mice were recorded, and the serum corticosterone level of the mice was assayed by enzyme-linked immunosorbent assay (ELISA). Results The micro-CT results showed significant trabecular bone loss, and 3D-ULD induced cortical bone loss in disused femurs as well as a decrease in the bone mineral density in the unloaded mice. TRAP staining and IHC-CTSK staining results indicated increases in the osteoclast number per bone perimeter (Oc.N/B.Pm) and the osteoclast surface per bone surface (Oc.S/BS) in the unloaded mice. The Ctsk, Trap and Mmp9 expression levels were significantly increased in the unloaded mice. Decreases in the ratio of the mineral surface to bone surface (MS/BS), mineral apposition rate (MAR) and bone formation rate per bone surface (BFR/BS) were found in unloaded mice in the 3D-ULD by double labelling. The IHC-DMP1 and ALP staining results showed decreases in the osteoblast number per bone perimeter (Ob.N/B.Pm) and osteoblast surface per bone surface (Ob. S/BS) in the mice unloaded in the 3D-ULD, and these mice also showed decreased Runx2, Alp and Dmp1 expression levels. Three-point bending test results showed that the mechanical properties were attenuated in the disused femurs of the unloaded mice. Less skin rupture and rare alterations in the thymus and spleen weights were found in the unloaded mice in the 3D-ULD. The ELISA results indicated the serum corticosterone level of the mice unloaded in the 3D-ULD was significantly lower than that of mice suspended by their tail. Conclusion This new disuse osteoporosis mouse model based on 3D-ULD could induce effective disuse bone loss with significantly alleviated side effects. Translational potential of this article This study proposes a new disuse osteoporosis mouse model based on 3D-ULD that can be used to better understand disuse bone loss in the future.
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5
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Che J, Ren W, Chen X, Wang F, Zhang G, Shang P. PTH 1-34 promoted bone formation by regulating iron metabolism in unloading-induced bone loss. Front Endocrinol (Lausanne) 2022; 13:1048818. [PMID: 36818465 PMCID: PMC9933505 DOI: 10.3389/fendo.2022.1048818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/31/2022] [Indexed: 02/05/2023] Open
Abstract
PTH 1-34 (teriparatide) is approved by FDA for the treatment of postmenopausal osteoporosis. Iron overload is a major contributing factor for bone loss induced by unloading. Whether iron metabolism is involved in the regulation of PTH 1-34 on unloading-induced osteoporosis has not yet been reported. Here, we found that PTH 1-34 attenuated bone loss in unloading mice. PTH 1-34 regulated the disturbance of iron metabolism in unloading mice by activating Nrf2 and further promoting hepcidin expression in the liver. In addition, the Nrf2 inhibitor selectively blocked hepcidin expression in the liver of unloading mice, which neutralized the inhibitory effect of PTH 1-34 on bone loss and the recovery of iron metabolism in unloading mice. Finally, we found that PTH 1-34 promoted the differentiation and inhibited apoptosis of osteoblasts by regulating iron metabolism and maintaining redox balance under unloading conditions. Our results suggested that PTH 1-34 promoted bone formation by regulating iron metabolism under unloading conditions.
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Affiliation(s)
- Jingmin Che
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, Guangdong, China
- Shaanxi Provincial Key Laboratory of Infection and Immune Diseases, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Weihao Ren
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, Guangdong, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- Key Laboratory for Space Bioscience and Biotechnology, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Xin Chen
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- Key Laboratory for Space Bioscience and Biotechnology, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Fang Wang
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- Key Laboratory for Space Bioscience and Biotechnology, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Gejing Zhang
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- Key Laboratory for Space Bioscience and Biotechnology, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Peng Shang
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, Guangdong, China
- Key Laboratory for Space Bioscience and Biotechnology, Northwestern Polytechnical University, Xi’an, Shaanxi, China
- *Correspondence: Peng Shang,
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6
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Lu L, Cai Y, Luo X, Wang Z, Fung SH, Jia H, Yu CL, Chan WY, Miu KK, Xiao W. A Core Omnigenic Non-coding Trait Governing Dex-Induced Osteoporotic Effects Identified Without DEXA. Front Pharmacol 2021; 12:750959. [PMID: 34899306 PMCID: PMC8651565 DOI: 10.3389/fphar.2021.750959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/20/2021] [Indexed: 12/15/2022] Open
Abstract
Iatrogenic glucocorticoid (GC)-induced osteoporosis (GIO) is an idiosyncratic form of secondary osteoporosis. Genetic predisposition among individuals may give rise to variant degree of phenotypic changes but there has yet been a documented unified pathway to explain the idiosyncrasy. In this study, we argue that the susceptibility to epigenetic changes governing molecular cross talks along the BMP and PI3K/Akt pathway may underline how genetic background dictate GC-induced bone loss. Concordantly, osteoblasts from BALB/c or C57BL/6 neonatal mice were treated with dexamethasone for transcriptome profiling. Furthermore, we also confirmed that GC-pre-conditioned mesenchymal stem cells (MSCs) would give rise to defective osteogenesis by instigating epigenetic changes which affected the accessibility of enhancer marks. In line with these epigenetic changes, we propose that GC modulates a key regulatory network involving the scavenger receptor Cd36 in osteoblasts pre-conditioning pharmacological idiosyncrasy in GIO.
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Affiliation(s)
- Li Lu
- Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou, China
| | - Yanzhen Cai
- Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou, China
| | - Xiaoling Luo
- Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou, China
| | - Zhangting Wang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Sin Hang Fung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Huanhuan Jia
- Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou, China.,Guangdong Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Chi Lam Yu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Wai Yee Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Kai Kei Miu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Wende Xiao
- Department of Orthopedics, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
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7
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Genetic variability affects the skeletal response to immobilization in founder strains of the diversity outbred mouse population. Bone Rep 2021; 15:101140. [PMID: 34761080 PMCID: PMC8566767 DOI: 10.1016/j.bonr.2021.101140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 12/13/2022] Open
Abstract
Mechanical unloading decreases bone volume and strength. In humans and mice, bone mineral density is highly heritable, and in mice the response to changes in loading varies with genetic background. Thus, genetic variability may affect the response of bone to unloading. As a first step to identify genes involved in bones' response to unloading, we evaluated the effects of unloading in eight inbred mouse strains: C57BL/6J, PWK/PhJ, WSB/EiJ, A/J, 129S1/SvImJ, NOD/ShiLtJ, NZO/HlLtJ, and CAST/EiJ. C57BL/6J and NOD/ShiLtJ mice had the greatest unloading-induced loss of diaphyseal cortical bone volume and strength. NZO/HlLtJ mice had the greatest metaphyseal trabecular bone loss, and C57BL/6J, WSB/EiJ, NOD/ShiLtJ, and CAST/EiJ mice had the greatest epiphyseal trabecular bone loss. Bone loss in the epiphyses displayed the highest heritability. With immobilization, mineral:matrix was reduced, and carbonate:phosphate and crystallinity were increased. A/J mice displayed the greatest unloading-induced loss of mineral:matrix. Changes in gene expression in response to unloading were greatest in NOD/ShiLtJ and CAST/EiJ mice. The most upregulated genes in response to unloading were associated with increased collagen synthesis and extracellular matrix formation. Our results demonstrate a strong differential response to unloading as a function of strain. Diversity outbred (DO) mice are a high-resolution mapping population derived from these eight inbred founder strains. These results suggest DO mice will be highly suited for examining the genetic basis of the skeletal response to unloading. Mouse strain affects bone's response to immobilization. Magnitude of bone loss from immobilization is heritable. Bone transcriptomic response to immobilization is influenced by genetic variation.
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8
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Metzger CE, Swallow EA, Stacy AJ, Allen MR. Strain-specific alterations in the skeletal response to adenine-induced chronic kidney disease are associated with differences in parathyroid hormone levels. Bone 2021; 148:115963. [PMID: 33878503 PMCID: PMC8102422 DOI: 10.1016/j.bone.2021.115963] [Citation(s) in RCA: 3] [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: 01/13/2021] [Revised: 03/26/2021] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
UNLABELLED Chronic kidney disease (CKD) leads to loss of cortical bone through cortical thinning and the development of cortical porosity. The goal of this current study was to assess cortical bone alterations to adenine-induced chronic kidney disease (CKD) in two strains of mice with known genetic differences in cortical thickness. We hypothesized that C3H mice with thicker cortices and baseline levels of intracortical remodeling would have greater cortical porosity in response to adenine-induced CKD compared to B6 animals. METHODS Female C57BL/6 J (B6) and C3H/Hej (C3H) at 16-weeks of age were given a diet with 0.2% adenine to induce CKD for 6 weeks followed by a control diet for 4 weeks. Age- and strain-matched controls were fed the control diet without adenine for the 10-week period (n = 8 per group per strain). RESULTS Both strains of adenine-fed mice had elevated blood urea nitrogen, demonstrating compromised kidney function, compared to strain-matched controls, but only B6 adenine mice had statistically higher parathyroid hormone (PTH), greater cortical porosity, high bone turnover rate, a greater percentage of osteocytes positive for RANKL and IL-17, and lower osteocyte apoptosis compared to B6 controls. C3H mice had intracortical remodeling present in both control and adenine mice, while B6 mice had intracortical remodeling present only in adenine mice. Adenine mice of both strains had lower cortical thickness and a higher percentage of osteocytes positive for TNF-α compared to controls. CONCLUSION While both strains of mice had biochemical markers of kidney disease, only B6 mice developed a phenotype with significantly elevated PTH, high bone turnover, and cortical porosity development. This work, in a model of progressive CKD, further confirms the role of chronically elevated PTH in the development of cortical porosity and demonstrates adenine-induced increases in PTH contribute to intracortical remodeling in B6 mice. Adenine-induced changes that occurred in both strains of mice, notably lower cortical thickness and a higher percentage of osteocytes expressing TNF-α, indicate potential PTH-independent responses to CKD.
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Affiliation(s)
- Corinne E Metzger
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Elizabeth A Swallow
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Alexander J Stacy
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Matthew R Allen
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Medicine - Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Biomedical Engineering, Indiana University Purdue University of Indianapolis, Indianapolis, IN, United States; Roudebush Veterans Administration Medical Center, Indianapolis, IN, United States.
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9
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Brent MB, Brüel A, Thomsen JS. A Systematic Review of Animal Models of Disuse-Induced Bone Loss. Calcif Tissue Int 2021; 108:561-575. [PMID: 33386477 DOI: 10.1007/s00223-020-00799-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Several different animal models are used to study disuse-induced bone loss. This systematic review aims to give a comprehensive overview of the animal models of disuse-induced bone loss and provide a detailed narrative synthesis of each unique animal model. METHODS PubMed and Embase were systematically searched for animal models of disuse from inception to November 30, 2019. In addition, Google Scholar and personal file archives were searched for relevant publications not indexed in PubMed or Embase. Two reviewers independently reviewed titles and abstracts for full-text inclusion. Data were extracted using a predefined extraction scheme to ensure standardization. RESULTS 1964 titles and abstracts were screened of which 653 full-text articles were included. The most common animal species used to model disuse were rats (59%) and mice (30%). Males (53%) where used in the majority of the studies and genetically modified animals accounted for 7%. Twelve different methods to induce disuse were identified. The most frequently used methods were hindlimb unloading (44%), neurectomy (15%), bandages and orthoses (15%), and botulinum toxin (9%). The median time of disuse was 21 days (quartiles: 14 days, 36 days) and the median number of animals per group subjected to disuse was 10 (quartiles: 7, 14). Random group allocation was reported in 43% of the studies. Fewer than 5% of the studies justified the number of animals per group by a sample size calculation to ensure adequate statistical power. CONCLUSION Multiple animal models of disuse-induced bone loss exist, and several species of animals have successfully been studied. The complexity of disuse-induced bone loss warrants rigid research study designs. This systematic review emphasized the need for standardization of animal disuse research and reporting.
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Affiliation(s)
- Mikkel Bo Brent
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
- Department of Biomedicine, Health, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark.
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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10
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Li B, Zhao J, Ma J, Chen W, Zhou C, Wei W, Li S, Li G, Xin G, Zhang Y, Liu J, Wang Y, Ma X. Cross-talk Between Histone and DNA Methylation Mediates Bone Loss in Hind Limb Unloading. J Bone Miner Res 2021; 36:956-967. [PMID: 33465813 DOI: 10.1002/jbmr.4253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/11/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022]
Abstract
Bone loss induced by mechanical unloading is a common skeletal disease, but the precise mechanism remains unclear. The current study investigated the role of histone methylation, a key epigenetic marker, and its cross-talk with DNA methylation in bone loss induced by mechanical unloading. The expression of G9a, ubiquitin-like with PHD and ring finger domains 1 (UHRF1), and DNA methylation transferase 1 (DNMT1) were increased in hind limb unloading (HLU) rats. This was accompanied by an increased level of histone H3 lysine 9 (H3K9) di-/tri-methylation at lncH19 promoter. Then, alteration of G9a, DNMT1, or UHRF1 expression significantly affected lncH19 level and osteogenic activity in UMR106 cells. Osteogenic gene expression and matrix mineralization were robustly promoted after simultaneous knockdown of G9a, DNMT1, and UHRF1. Furthermore, physical interactions of lncH19 promoter with G9a and DNMT1, as well as direct interactions among DNMT1, G9a, and UHRF1 were detected. Importantly, overexpression of DNMT1, G9a, or UHRF1, respectively, resulted in enrichment of H3K9me2/me3 and 5-methylcytosine at lncH19 promoter. Finally, in vivo rescue experiments indicated that knockdown of DNMT1, G9a, or UHRF1 significantly relieved bone loss in HLU rats. In conclusion, our research demonstrated the critical role of H3K9 methylation and its cross-talk with DNA methylation in regulating lncH19 expression and bone loss in HLU rats. Combined targeting of DNMT1, G9a, and UHRF1 could be a promising strategy for the treatment of bone loss induced by mechanical unloading. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Bing Li
- Joint Department, Tianjin Hospital, Tianjin, China
| | - Jie Zhao
- Orthopedic Department, Tianjin Hospital, Tianjin, China
| | - Jianxiong Ma
- Tianjin Orthopedic Research Institute, Tianjin, China
| | - Weibo Chen
- School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Ce Zhou
- School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Wuzeng Wei
- Joint Department, Tianjin Hospital, Tianjin, China
| | - Shuai Li
- Joint Department, Tianjin Hospital, Tianjin, China
| | - Guomin Li
- Joint Department, Tianjin Hospital, Tianjin, China
| | - Guosheng Xin
- Tianjin Orthopedic Research Institute, Tianjin, China
| | - Yang Zhang
- Tianjin Orthopedic Research Institute, Tianjin, China
| | - Jun Liu
- Joint Department, Tianjin Hospital, Tianjin, China
| | - Yinsong Wang
- School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Xinlong Ma
- Joint Department, Tianjin Hospital, Tianjin, China.,Orthopedic Department, Tianjin Hospital, Tianjin, China.,Tianjin Orthopedic Research Institute, Tianjin, China
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11
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Little-Letsinger SE, Pagnotti GM, McGrath C, Styner M. Exercise and Diet: Uncovering Prospective Mediators of Skeletal Fragility in Bone and Marrow Adipose Tissue. Curr Osteoporos Rep 2020; 18:774-789. [PMID: 33068251 PMCID: PMC7736569 DOI: 10.1007/s11914-020-00634-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW To highlight recent basic, translational, and clinical works demonstrating exercise and diet regulation of marrow adipose tissue (MAT) and bone and how this informs current understanding of the relationship between marrow adiposity and musculoskeletal health. RECENT FINDINGS Marrow adipocytes accumulate in the bone in the setting of not only hypercaloric intake (calorie excess; e.g., diet-induced obesity) but also with hypocaloric intake (calorie restriction; e.g., anorexia), despite the fact that these states affect bone differently. With hypercaloric intake, bone quantity is largely unaffected, whereas with hypocaloric intake, bone quantity and quality are greatly diminished. Voluntary running exercise in rodents was found to lower MAT and promote bone in eucaloric and hypercaloric states, while degrading bone in hypocaloric states, suggesting differential modulation of MAT and bone, dependent upon whole-body energy status. Energy status alters bone metabolism and bioenergetics via substrate availability or excess, which plays a key role in the response of bone and MAT to mechanical stimuli. Marrow adipose tissue (MAT) is a fat depot with a potential role in-as well as responsivity to-whole-body energy metabolism. Understanding the localized function of this depot in bone cell bioenergetics and substrate storage, principally in the exercised state, will aid to uncover putative therapeutic targets for skeletal fragility.
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Affiliation(s)
- Sarah E Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA.
| | - Gabriel M Pagnotti
- Department of Medicine, Division of Endocrinology, Indiana University, Indianapolis, IN, USA
| | - Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA
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12
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Hong AR, Kim K, Lee JY, Yang JY, Kim JH, Shin CS, Kim SW. Transformation of Mature Osteoblasts into Bone Lining Cells and RNA Sequencing-Based Transcriptome Profiling of Mouse Bone during Mechanical Unloading. Endocrinol Metab (Seoul) 2020; 35:456-469. [PMID: 32615730 PMCID: PMC7386115 DOI: 10.3803/enm.2020.35.2.456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 04/03/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND We investigated RNA sequencing-based transcriptome profiling and the transformation of mature osteoblasts into bone lining cells (BLCs) through a lineage tracing study to better understand the effect of mechanical unloading on bone loss. METHODS Dmp1-CreERt2(+):Rosa26R mice were injected with 1 mg of 4-hydroxy-tamoxifen three times a week starting at postnatal week 7, and subjected to a combination of botulinum toxin injection with left hindlimb tenotomy starting at postnatal week 8 to 10. The animals were euthanized at postnatal weeks 8, 9, 10, and 12. We quantified the number and thickness of X-gal(+) cells on the periosteum of the right and left femoral bones at each time point. RESULTS Two weeks after unloading, a significant decrease in the number and a subtle change in the thickness of X-gal(+) cells were observed in the left hindlimbs compared with the right hindlimbs. At 4 weeks after unloading, the decrease in the thickness was accelerated in the left hindlimbs, although the number of labeled cells was comparable. RNA sequencing analysis showed downregulation of 315 genes in the left hindlimbs at 2 and 4 weeks after unloading. Of these, Xirp2, AMPD1, Mettl11b, NEXN, CYP2E1, Bche, Ppp1r3c, Tceal7, and Gadl1 were upregulated during osteoblastogenic/osteocytic and myogenic differentiation in vitro. CONCLUSION These findings demonstrate that mechanical unloading can accelerate the transformation of mature osteoblasts into BLCs in the early stages of bone loss in vivo. Furthermore, some of the genes involved in this process may have a pleiotropic effect on both bone and muscle.
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Affiliation(s)
- A Ram Hong
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju,
Korea
| | - Kwangsoo Kim
- Seoul National University Hospital Biomedical Research Institute, Seoul,
Korea
| | - Ji Yeon Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Jae-Yeon Yang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Jung Hee Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Chan Soo Shin
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Sang Wan Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
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13
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Mulder B, Stock JT, Saers JPP, Inskip SA, Cessford C, Robb JE. Intrapopulation variation in lower limb trabecular architecture. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:112-129. [DOI: 10.1002/ajpa.24058] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 02/20/2020] [Accepted: 03/21/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Bram Mulder
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
| | - Jay T. Stock
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
- Department of Anthropology University of Western Ontario London Canada
- Department of Archaeology Max Planck Institute for the Science of Human History Jena Germany
| | - Jaap P. P. Saers
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
| | - Sarah A. Inskip
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
| | - Craig Cessford
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
| | - John E. Robb
- University of Cambridge, McDonald Institute for Archaeological Research Cambridge UK
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14
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Martínez-Martínez A, Muñoz-Islas E, Ramírez-Rosas MB, Acosta-González RI, Torres-Rodríguez HF, Jiménez-Andrade JM. Blockade of the colony-stimulating factor-1 receptor reverses bone loss in osteoporosis mouse models. Pharmacol Rep 2020; 72:1614-1626. [PMID: 32222915 DOI: 10.1007/s43440-020-00091-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/27/2020] [Accepted: 02/19/2020] [Indexed: 12/26/2022]
Abstract
BACKGROUND Mice lacking either colony-stimulating factor-1 (CSF-1) or its receptor, CSF-1R, display osteopetrosis. Accordingly, genetic deletion or pharmacological blockade of CSF-1 prevents the bone loss associated with estrogen deficiency. However, the role of CSF-1R in osteoporosis models of type-1 diabetes (T1D) and ovariectomy (OVX) has not been examined. Thus, we evaluated whether CSF-1R blockade would relieve the bone loss in a model of primary osteoporosis (female mice with OVX) and a model of secondary osteoporosis (female with T1D) using micro-computed tomography. METHODS Female ICR mice at 10 weeks underwent OVX or received five daily administrations of streptozotocin (ip, 50 mg/kg) to induce T1D. Four weeks after OVX and 14 weeks after first injection of streptozotocin, mice received an anti-CSF-1R (2G2) antibody (10 mg/kg, ip; once/week for 6 weeks) or vehicle. At the last day of antibody administration, mice were sacrificed and femur and tibia were harvested for micro-computed tomography analysis. RESULTS Mice with OVX had a significant loss of trabecular bone at the distal femoral and proximal tibial metaphysis. Chronic treatment with anti-CSF-1R significantly reversed the trabecular bone loss at these anatomical sites. Streptozotocin-induced T1D resulted in significant loss of trabecular bone at the femoral neck and cortical bone at the femoral mid-diaphysis. Chronic treatment with anti-CSF-1R antibody significantly reversed the bone loss observed in mice with T1D. CONCLUSION Our results demonstrate that blockade of CSF-1R signaling reverses bone loss in two different mouse models of osteoporosis.
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Affiliation(s)
- Arisaí Martínez-Martínez
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México
| | - Enriqueta Muñoz-Islas
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México
| | - Martha B Ramírez-Rosas
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México
| | - Rosa I Acosta-González
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México
| | - Héctor F Torres-Rodríguez
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México
| | - Juan M Jiménez-Andrade
- Laboratorio de Farmacología, Unidad Académica Multidisciplinaria Reynosa-Aztlán, Universidad Autónoma de Tamaulipas, Calle 16 y Lago de Chapala, Col. Aztlán, 88740, Reynosa, TAMPS, México.
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15
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Zhou T, Gao B, Fan Y, Liu Y, Feng S, Cong Q, Zhang X, Zhou Y, Yadav PS, Lin J, Wu N, Zhao L, Huang D, Zhou S, Su P, Yang Y. Piezo1/2 mediate mechanotransduction essential for bone formation through concerted activation of NFAT-YAP1-ß-catenin. eLife 2020; 9:52779. [PMID: 32186512 PMCID: PMC7112954 DOI: 10.7554/elife.52779] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/17/2020] [Indexed: 12/15/2022] Open
Abstract
Mechanical forces are fundamental regulators of cell behaviors. However, molecular regulation of mechanotransduction remain poorly understood. Here, we identified the mechanosensitive channels Piezo1 and Piezo2 as key force sensors required for bone development and osteoblast differentiation. Loss of Piezo1, or more severely Piezo1/2, in mesenchymal or osteoblast progenitor cells, led to multiple spontaneous bone fractures in newborn mice due to inhibition of osteoblast differentiation and increased bone resorption. In addition, loss of Piezo1/2 rendered resistant to further bone loss caused by unloading in both bone development and homeostasis. Mechanistically, Piezo1/2 relayed fluid shear stress and extracellular matrix stiffness signals to activate Ca2+ influx to stimulate Calcineurin, which promotes concerted activation of NFATc1, YAP1 and ß-catenin transcription factors by inducing their dephosphorylation as well as NFAT/YAP1/ß-catenin complex formation. Yap1 and ß-catenin activities were reduced in the Piezo1 and Piezo1/2 mutant bones and such defects were partially rescued by enhanced ß-catenin activities.
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Affiliation(s)
- Taifeng Zhou
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States.,Department of Orthopaedic Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, First Affiliated Hospital of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, China
| | - Bo Gao
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States.,Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yi Fan
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
| | - Yuchen Liu
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
| | - Shuhao Feng
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States.,Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangdong, China
| | - Qian Cong
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
| | - Xiaolei Zhang
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States.,Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Yaxing Zhou
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
| | - Prem S Yadav
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
| | - Jiachen Lin
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States.,Department of Orthopedic Surgery and Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Nan Wu
- Department of Orthopedic Surgery and Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Liang Zhao
- Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangdong, China
| | - Dongsheng Huang
- Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shuanhu Zhou
- Department of Orthopedic Surgery, Brigham and Women's Hospital, Boston, United States
| | - Peiqiang Su
- Department of Orthopaedic Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, First Affiliated Hospital of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, China
| | - Yingzi Yang
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, Boston, United States
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16
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Pagnotti GM, Styner M, Uzer G, Patel VS, Wright LE, Ness KK, Guise TA, Rubin J, Rubin CT. Combating osteoporosis and obesity with exercise: leveraging cell mechanosensitivity. Nat Rev Endocrinol 2019; 15:339-355. [PMID: 30814687 PMCID: PMC6520125 DOI: 10.1038/s41574-019-0170-1] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Osteoporosis, a condition of skeletal decline that undermines quality of life, is treated with pharmacological interventions that are associated with poor adherence and adverse effects. Complicating efforts to improve clinical outcomes, the incidence of obesity is increasing, predisposing the population to a range of musculoskeletal complications and metabolic disorders. Pharmacological management of obesity has yet to deliver notable reductions in weight and debilitating complications are rarely avoided. By contrast, exercise shows promise as a non-invasive and non-pharmacological method of regulating both osteoporosis and obesity. The principal components of exercise - mechanical signals - promote bone and muscle anabolism while limiting formation and expansion of fat mass. Mechanical regulation of bone and marrow fat might be achieved by regulating functions of differentiated cells in the skeletal tissue while biasing lineage selection of their common progenitors - mesenchymal stem cells. An inverse relationship between adipocyte versus osteoblast fate selection from stem cells is implicated in clinical conditions such as childhood obesity and increased marrow adiposity in type 2 diabetes mellitus, as well as contributing to skeletal frailty. Understanding how exercise-induced mechanical signals can be used to improve bone quality while decreasing fat mass and metabolic dysfunction should lead to new strategies to treat chronic diseases such as osteoporosis and obesity.
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Affiliation(s)
- Gabriel M Pagnotti
- School of Medicine, Division of Endocrinology, Indiana University, Indianapolis, IN, USA
| | - Maya Styner
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina, Chapel Hill, NC, USA
| | - Gunes Uzer
- College of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Vihitaben S Patel
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Laura E Wright
- School of Medicine, Division of Endocrinology, Indiana University, Indianapolis, IN, USA
| | - Kirsten K Ness
- Department of Epidemiology and Cancer Control, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Theresa A Guise
- School of Medicine, Division of Endocrinology, Indiana University, Indianapolis, IN, USA
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina, Chapel Hill, NC, USA
| | - Clinton T Rubin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA.
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17
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Zaitune CR, Fonseca TL, Capelo LP, Freitas FR, Beber EH, Dora JM, Wang CC, Miranda-Rodrigues M, Nonaka KO, Maia AL, Gouveia CHA. Abnormal Thyroid Hormone Status Differentially Affects Bone Mass Accrual and Bone Strength in C3H/HeJ Mice: A Mouse Model of Type I Deiodinase Deficiency. Front Endocrinol (Lausanne) 2019; 10:300. [PMID: 31156551 PMCID: PMC6530334 DOI: 10.3389/fendo.2019.00300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/26/2019] [Indexed: 12/26/2022] Open
Abstract
C3H/HeJ (C3H) mice are deficient of type I deiodinase (D1), an enzyme that activates thyroid hormone (TH), converting thyroxine (T4) to triiodothyronine (T3). Nevertheless, C3H mice present normal serum T3 and a gross euthyroid phenotype. To investigate if a global D1 deficiency interferes in the TH effects on bone, we compared bone growth, bone mass accrual and bone strength of C3H and C57BL/6J (B6) mice under abnormal TH status. Four-week-old female mice of both strains were grouped as Euthyroid, Hypothyroid (pharmacologically-induced), 1xT4 and 10xT4 (hypothyroid animals receiving 1- or 10-fold the physiological dose of T4 /day/16 weeks). Hypothyroidism and TH excess similarly impaired body weight (BW) gain and body growth in both mice strains. In contrast, whereas hypothyroidism only slightly impaired bone mineral density (BMD) accrual in B6 mice, it severely impaired BMD accrual in C3H mice. No differences were observed in serum and bone concentrations of T3 between hypothyroid animals of both strains. Interestingly, treatment with 10xT4 was less deleterious to BMD accrual in C3H than in B6 mice and resulted in less elevated T3 serum levels in B6 than in C3H mice, which is probably explained by the lower D1 activity in C3H mice. In addition, hypothyroidism decreased bone strength only in C3H but not in B6 mice, while TH excess decreased this parameter in both strains. These findings indicate that D1 deficiency contributes to the TH excess-induced differences in bone mass accrual in C3H vs. B6 mice and suggest that deiodinase-unrelated genetic factors might account for the different skeleton responses to hypothyroidism between strains.
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Affiliation(s)
- Clarissa R. Zaitune
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Institute of Healthy Sciences, Paulista University, São Paulo, Brazil
| | - Tatiana L. Fonseca
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Chicago, Chigago, IL, United States
| | - Luciane P. Capelo
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Institute of Science and Technology, Federal University of São Paulo, São Paulo, Brazil
| | - Fatima R. Freitas
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Heart Institute (InCor) of Medical School Hospital, University of São Paulo, São Paulo, Brazil
| | - Eduardo H. Beber
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo, Vitoria, Brazil
| | - José M. Dora
- Endocrine Division, Hospital de Clinicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Charles C. Wang
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Manuela Miranda-Rodrigues
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Keico O. Nonaka
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Ana L. Maia
- Endocrine Division, Hospital de Clinicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Cecilia H. A. Gouveia
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- *Correspondence: Cecilia H. A. Gouveia
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18
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Alexander JJ, Sankaran JS, Seldeen KL, Thiyagarajan R, Jacob A, Quigg RJ, Troen BR, Judex S. Absence of complement factor H alters bone architecture and dynamics. Immunobiology 2018; 223:761-771. [DOI: 10.1016/j.imbio.2018.07.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/22/2018] [Accepted: 07/28/2018] [Indexed: 01/03/2023]
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19
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Copes LE, Schutz H, Dlugsoz EM, Judex S, Garland T. Locomotor activity, growth hormones, and systemic robusticity: An investigation of cranial vault thickness in mouse lines bred for high endurance running. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:442-458. [DOI: 10.1002/ajpa.23446] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 02/02/2018] [Accepted: 02/06/2018] [Indexed: 12/30/2022]
Affiliation(s)
- L. E. Copes
- Department of Medical Sciences, Frank H. Netter MD School of MedicineQuinnipiac UniversityHamden Connecticut06518
| | - H. Schutz
- Department of BiologyPacific Lutheran UniversityTacoma Washington, DC98447
| | - E. M. Dlugsoz
- Department of BiologyUniversity of CaliforniaRiverside, Riverside California92521
| | - S. Judex
- Department of Biomedical EngineeringStony Brook UniversityStony Brook New York11794
| | - T. Garland
- Department of BiologyUniversity of CaliforniaRiverside, Riverside California92521
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20
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Yu K, Doherty AH, Genik PC, Gookin SE, Roteliuk DM, Wojda SJ, Jiang ZS, McGee-Lawrence ME, Weil MM, Donahue SW. Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice. LIFE SCIENCES IN SPACE RESEARCH 2017; 15:62-68. [PMID: 29198315 DOI: 10.1016/j.lssr.2017.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/31/2017] [Accepted: 08/11/2017] [Indexed: 06/07/2023]
Abstract
During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.
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Affiliation(s)
- Kanglun Yu
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang, Hunan, China; Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Alison H Doherty
- Department of Medical Education, WWAMI Medical Education Program, University of Wyoming, Laramie, WY, USA
| | - Paula C Genik
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Sara E Gookin
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Danielle M Roteliuk
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Samantha J Wojda
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Zhi-Sheng Jiang
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang, Hunan, China
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Michael M Weil
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Seth W Donahue
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA.
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21
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Differences in bone structure and unloading-induced bone loss between C57BL/6N and C57BL/6J mice. Mamm Genome 2017; 28:476-486. [PMID: 28913652 DOI: 10.1007/s00335-017-9717-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/06/2017] [Indexed: 12/24/2022]
Abstract
The C57BL/6 mouse, the most frequently utilized animal model in biomedical research, is in use as several substrains, all of which differ by a small array of genomic differences. Two of these substrains, C57BL/6J (B6J) and C57BL/6N (B6N), are commonly used but it is unclear how phenotypically similar or different they are. Here, we tested whether adolescent B6N mice have a bone phenotype and respond to the loss of weightbearing differently than B6J. At 9 weeks of age, normally ambulating B6N had lower trabecular bone volume fraction but greater bone formation rates and osteoblast surfaces than corresponding B6J. At 11 weeks of age, differences in trabecular indices persisted between the substrains but differences in cellular activity had ceased. Cortical bone indices were largely similar between the two substrains. Hindlimb unloading (HLU) induced similar degeneration of trabecular architecture and cellular activity in both substrains when comparing 11-week-old HLU mice to 11-week-old controls. However, unloaded B6N mice had smaller cortices than B6J. When comparing HLU to 9 weeks baseline control mice, deterioration in trabecular separation, osteoblast indices, and endocortical variables was significantly greater in B6N than B6J. These data indicate specific developmental differences in bone formation and morphology between B6N and B6J mice, giving rise to a differential response to mechanical unloading that may be modulated, in part, by the genes Herc2, Myo18b, and Acan. Our results emphasize that these substrains cannot be used interchangeably at least for investigations in which the phenotypic makeup and its response to extraneous stimuli are of interest.
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22
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Mustonen AMJ, Finnilä MAJ, Puukka KS, Jämsä TJ, Saarakkala S, Tuukkanen JK, Nieminen TP. Raccoon dog model shows preservation of bone during prolonged catabolism and reduced physical activity. ACTA ACUST UNITED AC 2017; 220:2196-2202. [PMID: 28373598 DOI: 10.1242/jeb.135475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/27/2017] [Indexed: 11/20/2022]
Abstract
The raccoon dog (Nyctereutes procyonoides) is a promising animal model capable of preventing disuse-induced osteoporosis. Previous data suggest that this species resembles bears in the preservation of bone mass and biomechanical properties during prolonged passivity and catabolism. This longitudinal study examined the osteological properties of tibiae in farm-bred raccoon dogs that were either fed or fasted (n=6 per group) for a 10 week period. Peripheral quantitative computed tomography was utilized and plasma markers of bone turnover measured before fasting and at 9 weeks followed by mechanical testing (three-point bending), micro-computed tomography and Fourier transform infrared imaging at 10 weeks. Passive wintering with prolonged catabolism (body mass loss 32%) had no significant effects on bone mineralization, porosity or strength. The concentration of C-terminal telopeptide of type I collagen, indicative of bone resorption, increased in the plasma of the fasted raccoon dogs, while the bone formation markers were unchanged. The levels of 25-hydroxyvitamin D were reduced in the fasted animals. Based on these data, the preservation of bone in wintering raccoon dogs shares characteristics with that of bears with no apparent decrease in the formation of bone but increased resorption. To conclude, raccoon dogs were able to minimize bone loss during a 10 week period of catabolism and passivity.
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Affiliation(s)
- Anne-Mari J Mustonen
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Institute of Biomedicine/Anatomy, PO Box 1627, Kuopio FI-70211, Finland .,University of Eastern Finland, Faculty of Science and Forestry, Department of Environmental and Biological Sciences, PO Box 111, Joensuu FI-80101, Finland
| | - Mikko A J Finnilä
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,University of Eastern Finland, Faculty of Science and Forestry, Department of Applied Physics, PO Box 1627, Kuopio FI-70211, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland
| | - Katri S Puukka
- NordLab Oulu, Oulu University Hospital, PO Box 500, Oulu FI-90029, OYS, Finland.,University of Oulu, Faculty of Medicine, Department of Clinical Chemistry, PO Box 8000, Oulu FI-90014, Finland
| | - Timo J Jämsä
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, PO Box 50, Oulu FI-90029, Finland
| | - Simo Saarakkala
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, PO Box 50, Oulu FI-90029, Finland
| | - Juha K Tuukkanen
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,University of Oulu, Faculty of Medicine, Research Group of Cancer Research and Translational Medicine, PO Box 5000, Oulu FI-90014, Finland
| | - T Petteri Nieminen
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Institute of Biomedicine/Anatomy, PO Box 1627, Kuopio FI-70211, Finland.,University of Eastern Finland, Faculty of Science and Forestry, Department of Environmental and Biological Sciences, PO Box 111, Joensuu FI-80101, Finland
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23
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Birkhold AI, Razi H, Duda GN, Checa S, Willie BM. Tomography-Based Quantification of Regional Differences in Cortical Bone Surface Remodeling and Mechano-Response. Calcif Tissue Int 2017; 100:255-270. [PMID: 27999894 DOI: 10.1007/s00223-016-0217-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/02/2016] [Indexed: 01/27/2023]
Abstract
Bone has an adaptive capacity to maintain structural integrity. However, there seems to be a heterogeneous cortical (re)modeling response to loading at different regions within the same bone, which may lead to inconsistent findings since most studies analyze only one region. It remains unclear if the local mechanical environment is responsible for this heterogeneous response and whether both formation and resorption are affected. Thus, we compared the formation and resorptive response to in vivo loading and the strain environment at two commonly analyzed regions in the mouse tibia, the mid-diaphysis and proximal metaphysis. We quantified cortical surface (re)modeling by tracking changes between geometrically aligned consecutive in vivo micro-tomography images (time lapse 15 days). We investigated the local mechanical strain environment using finite element analyses. The relationship between mechanical stimuli and surface (re)modeling was examined by sub-dividing the mid-diaphysis and proximal metaphysis into 32 sub-regions. In response to loading, metaphyseal cortical bone (re)modeled predominantly at the periosteal surface, whereas diaphyseal (re)modeling was more pronounced at the endocortical surface. Furthermore, different set points and slopes of the relationship between engendered strains and remodeling response were found for the endosteal and periosteal surfaces at the metaphyseal and diaphyseal regions. Resorption was correlated with strain at the endocortical, but not the periosteal surfaces, whereas, formation correlated with strain at all surfaces, except at the metaphyseal periosteal surface. Therefore, besides mechanical stimuli, other non-mechanical factors are likely driving regional differences in adaptation. Studies investigating adaptation to loading or other treatments should consider region-specific (re)modeling differences.
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Affiliation(s)
- Annette I Birkhold
- Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Continuum Biomechanics and Mechanobiology Research Group, Institute of Applied Mechanics, University of Stuttgart, Stuttgart, Germany
| | - Hajar Razi
- Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Georg N Duda
- Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sara Checa
- Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Bettina M Willie
- Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany.
- Department of Pediatric Surgery, McGill University, Research Centre, Shriners Hospital for Children-Canada, 1003 Decarie Blvd, Montreal, H4A 0A9, Canada.
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24
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Anderson MJ, Diko S, Baehr LM, Baar K, Bodine SC, Christiansen BA. Contribution of mechanical unloading to trabecular bone loss following non-invasive knee injury in mice. J Orthop Res 2016; 34:1680-1687. [PMID: 26826014 PMCID: PMC5603199 DOI: 10.1002/jor.23178] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/28/2016] [Indexed: 02/04/2023]
Abstract
Development of osteoarthritis commonly involves degeneration of epiphyseal trabecular bone. In previous studies, we observed 30-44% loss of epiphyseal trabecular bone (BV/TV) from the distal femur within 1 week following non-invasive knee injury in mice. Mechanical unloading (disuse) may contribute to this bone loss; however, it is unclear to what extent the injured limb is unloaded following injury, and whether disuse can fully account for the observed magnitude of bone loss. In this study, we investigated the contribution of mechanical unloading to trabecular bone changes observed following non-invasive knee injury in mice (female C57BL/6N). We investigated changes in gait during treadmill walking, and changes in voluntary activity level using Open Field analysis at 4, 14, 28, and 42 days post-injury. We also quantified epiphyseal trabecular bone using μCT and weighed lower-limb muscles to quantify atrophy following knee injury in both ground control and hindlimb unloaded (HLU) mice. Gait analysis revealed a slightly altered stride pattern in the injured limb, with a decreased stance phase and increased swing phase. However, Open Field analysis revealed no differences in voluntary movement between injured and sham mice at any time point. Both knee injury and HLU resulted in comparable magnitudes of trabecular bone loss; however, HLU resulted in considerably more muscle loss than knee injury, suggesting another mechanism contributing to bone loss following injury. Altogether, these data suggest that mechanical unloading likely contributes to trabecular bone loss following non-invasive knee injury, but the magnitude of this bone loss cannot be fully explained by disuse. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1680-1687, 2016.
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Affiliation(s)
- Matthew J. Anderson
- University of California-Davis Medical Center, Department of Orthopaedic Surgery
| | - Sindi Diko
- University of California-Davis Medical Center, Department of Orthopaedic Surgery
| | - Leslie M. Baehr
- University of California-Davis, Department of Neurobiology, Physiology, and Behavior; Department of Physiology and Membrane Biology
| | - Keith Baar
- University of California-Davis, Department of Neurobiology, Physiology, and Behavior; Department of Physiology and Membrane Biology
| | - Sue C. Bodine
- University of California-Davis, Department of Neurobiology, Physiology, and Behavior; Department of Physiology and Membrane Biology
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25
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Reilly BD, Franklin CE. Prevention of muscle wasting and osteoporosis: the value of examining novel animal models. J Exp Biol 2016; 219:2582-95. [DOI: 10.1242/jeb.128348] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ABSTRACT
Bone mass and skeletal muscle mass are controlled by factors such as genetics, diet and nutrition, growth factors and mechanical stimuli. Whereas increased mechanical loading of the musculoskeletal system stimulates an increase in the mass and strength of skeletal muscle and bone, reduced mechanical loading and disuse rapidly promote a decrease in musculoskeletal mass, strength and ultimately performance (i.e. muscle atrophy and osteoporosis). In stark contrast to artificially immobilised laboratory mammals, animals that experience natural, prolonged bouts of disuse and reduced mechanical loading, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in musculoskeletal performance. What factors modulate skeletal muscle and bone mass, and what physiological and molecular mechanisms protect against losses of muscle and bone during dormancy and following arousal? Understanding the events that occur in different organisms that undergo natural periods of prolonged disuse and suffer negligible musculoskeletal deterioration could not only reveal novel regulatory factors but also might lead to new therapeutic options. Here, we review recent work from a diverse array of species that has revealed novel information regarding physiological and molecular mechanisms that dormant animals may use to conserve musculoskeletal mass despite prolonged inactivity. By highlighting some of the differences and similarities in musculoskeletal biology between vertebrates that experience disparate modes of dormancy, it is hoped that this Review will stimulate new insights and ideas for future studies regarding the regulation of atrophy and osteoporosis in both natural and clinical models of muscle and bone disuse.
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Affiliation(s)
- Beau D. Reilly
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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26
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Macias BR, Lima F, Swift JM, Shirazi-Fard Y, Greene ES, Allen MR, Fluckey J, Hogan HA, Braby L, Wang S, Bloomfield SA. Simulating the Lunar Environment: Partial Weightbearing and High-LET Radiation-Induce Bone Loss and Increase Sclerostin-Positive Osteocytes. Radiat Res 2016; 186:254-63. [PMID: 27538114 DOI: 10.1667/rr13579.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Exploration missions to the Moon or Mars will expose astronauts to galactic cosmic radiation and low gravitational fields. Exposure to reduced weightbearing and radiation independently result in bone loss. However, no data exist regarding the skeletal consequences of combining low-dose, high-linear energy transfer (LET) radiation and partial weightbearing. We hypothesized that simulated galactic cosmic radiation would exacerbate bone loss in animals held at one-sixth body weight (G/6) without radiation exposure. Female BALB/cByJ four-month-old mice were randomly assigned to one of the following treatment groups: 1 gravity (1G) control; 1G with radiation; G/6 control; and G/6 with radiation. Mice were exposed to either silicon-28 or X-ray radiation. (28)Si radiation (300 MeV/nucleon) was administered at acute doses of 0 (sham), 0.17 and 0.5 Gy, or in three fractionated doses of 0.17 Gy each over seven days. X radiation (250 kV) was administered at acute doses of 0 (sham), 0.17, 0.5 and 1 Gy, or in three fractionated doses of 0.33 Gy each over 14 days. Bones were harvested 21 days after the first exposure. Acute 1 Gy X-ray irradiation during G/6, and acute or fractionated 0.5 Gy (28)Si irradiation during 1G resulted in significantly lower cancellous mass [percentage bone volume/total volume (%BV/TV), by microcomputed tomography]. In addition, G/6 significantly reduced %BV/TV compared to 1G controls. When acute X-ray irradiation was combined with G/6, distal femur %BV/TV was significantly lower compared to G/6 control. Fractionated X-ray irradiation during G/6 protected against radiation-induced losses in %BV/TV and trabecular number, while fractionated (28)Si irradiation during 1G exacerbated the effects compared to single-dose exposure. Impaired bone formation capacity, measured by percentage mineralizing surface, can partially explain the lower cortical bone thickness. Moreover, both partial weightbearing and (28)Si-ion exposure contribute to a higher proportion of sclerostin-positive osteocytes in cortical bone. Taken together, these data suggest that partial weightbearing and low-dose, high-LET radiation negatively impact maintenance of bone mass by lowering bone formation and increasing bone resorption. The impaired bone formation response is associated with sclerostin-induced suppression of Wnt signaling. Therefore, exposure to low-dose, high-LET radiation during long-duration spaceflight missions may reduce bone formation capacity, decrease cancellous bone mass and increase bone resorption. Future countermeasure strategies should aim to restore mechanical loads on bone to those experienced in one gravity. Moreover, low-doses of high-LET radiation during long-duration spaceflight should be limited or countermeasure strategies employed to mitigate bone loss.
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Affiliation(s)
| | | | | | | | | | - M R Allen
- g Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | | | - H A Hogan
- b Biomedical Engineering.,c Mechanical Engineering
| | | | - Suojin Wang
- f Statistics, Texas A&M University, College Station, Texas, 77843 and
| | - S A Bloomfield
- a Health and Kinesiology.,d Intercollegiate Faculty of Nutrition
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27
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Cabahug-Zuckerman P, Frikha-Benayed D, Majeska RJ, Tuthill A, Yakar S, Judex S, Schaffler MB. Osteocyte Apoptosis Caused by Hindlimb Unloading is Required to Trigger Osteocyte RANKL Production and Subsequent Resorption of Cortical and Trabecular Bone in Mice Femurs. J Bone Miner Res 2016; 31:1356-65. [PMID: 26852281 PMCID: PMC5488280 DOI: 10.1002/jbmr.2807] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 12/20/2022]
Abstract
Osteocyte apoptosis is essential to activate bone remodeling in response to fatigue microdamage and estrogen withdrawal, such that apoptosis inhibition in vivo prevents the onset of osteoclastic resorption. Osteocyte apoptosis has also been spatially linked to bone resorption owing to disuse, but whether apoptosis plays a similar controlling role is unclear. We, therefore, 1) evaluated the spatial and temporal effects of disuse from hindlimb unloading (HLU) on osteocyte apoptosis, receptor activator of NF-κB ligand (RANKL) expression, bone resorption, and loss in mouse femora, and 2) tested whether osteocyte apoptosis was required to activate osteoclastic activity in cortical and trabecular bone by treating animals subjected to HLU with the pan-caspase apoptosis inhibitor, QVD (quinolyl-valyl-O-methylaspartyl-[-2,6-difluorophenoxy]-methylketone). Immunohistochemistry was used to identify apoptotic and RANKL-producing osteocytes in femoral diaphysis and distal trabecular bone, and µCT was used to determine the extent of trabecular bone loss owing to HLU. In both cortical and trabecular bone, 5 days of HLU increased osteocyte apoptosis significantly (3- and 4-fold, respectively, p < 0.05 versus Ctrl). At day 14, the apoptotic osteocyte number in femoral cortices declined to near control levels but remained elevated in trabeculae (3-fold versus Ctrl, p < 0.05). The number of osteocytes producing RANKL in both bone compartments was also significantly increased at day 5 of HLU (>1.5-fold versus Ctrl, p < 0.05) and further increased by day 14. Increases in osteocyte apoptosis and RANKL production preceded increases in bone resorption at both endocortical and trabecular surfaces. QVD completely inhibited not only the HLU-triggered increases in osteocyte apoptosis but also RANKL production and activation of bone resorption at both sites. Finally, µCT studies revealed that apoptosis inhibition completely prevented the trabecular bone loss caused by HLU. Together these data indicate that osteocyte apoptosis plays a central and controlling role in triggering osteocyte RANKL production and the activation of new resorption leading to bone loss in disuse. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Dorra Frikha-Benayed
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Robert J Majeska
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Alyssa Tuthill
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Shoshana Yakar
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA
| | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Mitchell B Schaffler
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
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28
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Li B, Sankaran JS, Judex S. Trabecular and Cortical Bone of Growing C3H Mice Is Highly Responsive to the Removal of Weightbearing. PLoS One 2016; 11:e0156222. [PMID: 27223115 PMCID: PMC4880346 DOI: 10.1371/journal.pone.0156222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/11/2016] [Indexed: 01/08/2023] Open
Abstract
Genetic make-up strongly influences the skeleton’s susceptibility to the loss of weight bearing with some inbred mouse strains experiencing great amounts of bone loss while others lose bone at much smaller rates. At young adulthood, female inbred C3H/HeJ (C3H) mice are largely resistant to catabolic pressure induced by unloading. Here, we tested whether the depressed responsivity to unloading is inherent to the C3H genetic make-up or whether a younger age facilitates a robust skeletal response to unloading. Nine-week-old, skeletally immature, female C3H mice were subjected to 3wk of hindlimb unloading (HLU, n = 12) or served as normal baseline controls (BC, n = 10) or age-matched controls (AC, n = 12). In all mice, cortical and trabecular architecture of the femur, as well as levels of bone formation and resorption, were assessed with μCT, histomorphometry, and histology. Changes in bone marrow progenitor cell populations were determined with flow cytometry. Following 21d of unloading, HLU mice had 52% less trabecular bone in the distal femur than normal age-matched controls. Reflecting a loss of trabecular tissue compared to baseline controls, trabecular bone formation rates (BFR/BS) in HLU mice were 40% lower than in age-matched controls. Surfaces undergoing osteoclastic resorption were not significantly different between groups. In the mid-diaphysis, HLU inhibited cortical bone growth leading to 14% less bone area compared to age-matched controls. Compared to AC, BFR/BS of HLU mice were 53% lower at the endo-cortical surface and 49% lower at the periosteal surface of the mid-diaphysis. The enriched osteoprogenitor cell population (OPC) comprised 2% of the bone marrow stem cells in HLU mice, significantly different from 3% OPC in the AC group. These data show that bone tissue in actively growing C3H mice is lost rapidly, or fails to grow, during the removal of functional weight bearing—in contrast to the insignificant response previously demonstrated in female young adult C3H mice. Thus, the attributed low sensitivity of the C3H mouse strain to the loss of mechanical signals is not apparent at a young age and this trait therefore does not reflect a genetic regulation throughout the life span of this strain. These results highlight the significance of age in modulating the contribution of genetics in orchestrating bone’s response to unloading and that the skeletal unresponsiveness of young adult C3H mice to the loss of weight bearing is not genetically hard-wired.
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Affiliation(s)
- Bing Li
- Department of Orthopedics, Tianjin Hospital, Tianjin, 300211, China
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Jeyantt Srinivas Sankaran
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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29
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Pagnotti GM, Styner M. Exercise Regulation of Marrow Adipose Tissue. Front Endocrinol (Lausanne) 2016; 7:94. [PMID: 27471493 PMCID: PMC4943947 DOI: 10.3389/fendo.2016.00094] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 07/04/2016] [Indexed: 12/20/2022] Open
Abstract
Despite association with low bone density and skeletal fractures, marrow adipose tissue (MAT) remains poorly understood. The marrow adipocyte originates from the mesenchymal stem cell (MSC) pool that also gives rise to osteoblasts, chondrocytes, and myocytes, among other cell types. To date, the presence of MAT has been attributed to preferential biasing of MSC into the adipocyte rather than osteoblast lineage, thus negatively impacting bone formation. Here, we focus on understanding the physiology of MAT in the setting of exercise, dietary interventions, and pharmacologic agents that alter fat metabolism. The beneficial effect of exercise on musculoskeletal strength is known: exercise induces bone formation, encourages growth of skeletally supportive tissues, inhibits bone resorption, and alters skeletal architecture through direct and indirect effects on a multiplicity of cells involved in skeletal adaptation. MAT is less well studied due to the lack of reproducible quantification techniques. In recent work, osmium-based 3D quantification shows a robust response of MAT to both dietary and exercise intervention in that MAT is elevated in response to high-fat diet and can be suppressed following daily exercise. Exercise-induced bone formation correlates with suppression of MAT, such that exercise effects might be due to either calorie expenditure from this depot or from mechanical biasing of MSC lineage away from fat and toward bone, or a combination thereof. Following treatment with the anti-diabetes drug rosiglitazone - a PPARγ-agonist known to increase MAT and fracture risk - mice demonstrate a fivefold higher femur MAT volume compared to the controls. In addition to preventing MAT accumulation in control mice, exercise intervention significantly lowers MAT accumulation in rosiglitazone-treated mice. Importantly, exercise induction of trabecular bone volume is unhindered by rosiglitazone. Thus, despite rosiglitazone augmentation of MAT, exercise significantly suppresses MAT volume and induces bone formation. That exercise can both suppress MAT volume and increase bone quantity, notwithstanding the skeletal harm induced by rosiglitazone, underscores exercise as a powerful regulator of bone remodeling, encouraging marrow stem cells toward the osteogenic lineage to fulfill an adaptive need for bone formation. Thus, exercise represents an effective strategy to mitigate the deleterious effects of overeating and iatrogenic etiologies on bone and fat.
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Affiliation(s)
- Gabriel M. Pagnotti
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
- *Correspondence: Maya Styner,
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30
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MANSKE SARAHL, VIJAYARAGHAVAN SURABHI, TUTHILL ALYSSA, BRUTUS OLIVIER, YANG JIE, GUPTA SHIKHA, JUDEX STEFAN. Extending Rest between Unloading Cycles Does Not Enhance Bone’s Long-Term Recovery. Med Sci Sports Exerc 2015; 47:2191-200. [DOI: 10.1249/mss.0000000000000636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Lerebours C, Buenzli PR, Scheiner S, Pivonka P. A multiscale mechanobiological model of bone remodelling predicts site-specific bone loss in the femur during osteoporosis and mechanical disuse. Biomech Model Mechanobiol 2015; 15:43-67. [DOI: 10.1007/s10237-015-0705-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/05/2015] [Indexed: 11/30/2022]
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32
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Lodberg A, Vegger JB, Jensen MV, Larsen CM, Thomsen JS, Brüel A. Immobilization induced osteopenia is strain specific in mice. Bone Rep 2015; 2:59-67. [PMID: 28377955 PMCID: PMC5365160 DOI: 10.1016/j.bonr.2015.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 03/18/2015] [Accepted: 04/13/2015] [Indexed: 11/30/2022] Open
Abstract
Immobilization causes rapid and massive bone loss. By comparing Botulinum Toxin A (BTX)-induced bone loss in mouse strains with different genetic backgrounds we investigated whether the genetic background had an influence on the severity of the osteopenia. Secondly, we investigated whether BTX had systemic effects on bone. Female mice from four inbred mouse strains (BALB/cJ, C57BL/6 J, DBA/2 J, and C3H/HeN) were injected unilaterally with BTX (n = 10/group) or unilaterally with saline (n = 10/group). Mice were euthanized after 21 days, and the bone properties evaluated using μCT, DXA, bone histomorphometry, and mechanical testing. BTX resulted in substantially lower trabecular bone volume fraction (BV/TV) and trabecular thickness in all mouse strains. The deterioration of BV/TV was significantly greater in C57BL/6 J (− 57%) and DBA/2 J (− 60%) than in BALB/cJ (− 45%) and C3H/HeN (− 34%) mice. The loss of femoral neck fracture strength was significantly greater in C57BL/6 J (− 47%) and DBA/2 J (− 45%) than in C3H (− 25%) mice and likewise the loss of mid-femoral fracture strength was greater in C57BL/6 J (− 17%), DBA/2 J (− 12%), and BALB/cJ (− 9%) than in C3H/HeN (− 1%) mice, which were unaffected. Using high resolution μCT we found no evidence of a systemic effect on any of the microstructural parameters of the contralateral limb. Likewise, there was no evidence of a systemic effect on the bone strength in any mouse strain. We did, however, find a small systemic effect on aBMD in DBA/2 J and C3H/HeN mice. The present study shows that BTX-induced immobilization causes the greatest loss of cortical and trabecular bone in C57BL/6 J and DBA/2 J mice. A smaller loss of bone microstructure and fracture strength was seen in BALB/cJ mice, while the bone microstructure and fracture strength of C3H/HeN mice were markedly less affected. This indicates that BTX-induced loss of bone is mouse strain dependent. We found only minimal systemic effects of BTX. Botulinum Toxin A (Botox) causes only minimal systemic effects in mice. The degree of immobilization induced osteopenia is highly strain specific in mice. The greatest degree of bone loss was observed with C57BL/6 J and DBA/2 J mice followed by BALB/cJ mice after Botox-injection. C3H/HeN mice had the smallest bone loss following Botox-injection.
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Affiliation(s)
- Andreas Lodberg
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jens Bay Vegger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | | | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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33
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Komori T. Animal models for osteoporosis. Eur J Pharmacol 2015; 759:287-94. [PMID: 25814262 DOI: 10.1016/j.ejphar.2015.03.028] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/08/2015] [Accepted: 03/12/2015] [Indexed: 11/30/2022]
Abstract
The major types of osteoporosis in humans are postmenopausal osteoporosis, disuse osteoporosis, and glucocorticoid-induced osteoporosis. Animal models for postmenopausal osteoporosis are generated by ovariectomy. Bone loss occurs in estrogen deficiency due to enhanced bone resorption and impaired osteoblast function. Estrogen receptor α induces osteoclast apoptosis, but the mechanism for impaired osteoblast function remains to be clarified. Animal models for unloading are generated by tail suspension or hind limb immobilization by sciatic neurectomy, tenotomy, or using plaster cast. Unloading inhibits bone formation and enhances bone resorption, and the involvement of the sympathetic nervous system in it needs to be further investigated. The osteocyte network regulates bone mass by responding to mechanical stress. Osteoblast-specific BCL2 transgenic mice, in which the osteocyte network is completely disrupted, can be a mouse model for the evaluation of osteocyte functions. Glucocorticoid treatment inhibits bone formation and enhances bone resorption, and markedly reduces cancellous bone in humans and large animals, but not consistently in rodents.
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Affiliation(s)
- Toshihisa Komori
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
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Wallace IJ, Gupta S, Sankaran J, Demes B, Judex S. Bone shaft bending strength index is unaffected by exercise and unloading in mice. J Anat 2015; 226:224-8. [PMID: 25645569 DOI: 10.1111/joa.12277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2014] [Indexed: 11/30/2022] Open
Abstract
Anthropologists frequently use the shaft bending strength index to infer the physical activity levels of humans living in the past from their lower limb bone remains. This index is typically calculated as the ratio of bone shaft second moments of area about orthogonal principal axes (i.e. I(max)/I(min)). Individuals with high I(max)/I(min) values are inferred to have been very active, whereas individuals with low values are inferred to have been more sedentary. However, there is little direct evidence that activity has a causal and predictable effect on the shaft bending strength index. Here, we report the results of two experiments that were designed to test the model within which anthropologists commonly interpret the shaft bending strength index. In the first experiment, mice were treated daily with treadmill exercise for 1 month to simulate a high-activity lifestyle. In the second experiment, in an attempt to simulate a low-activity lifestyle, functional weight-bearing was removed from the hindlimbs of mice for 1 month. Femoral mid-shaft structure was determined with μCT. We found that while exercise resulted in significant enhancement of I(max) and I(min) compared with controls, it failed to significantly increase the I(max)/I(min)index. Similarly, stunted bone growth caused by unloading resulted in significantly diminished I(max) and I(min) compared with controls, but low activity did not lead to significantly decreased I(max)/I(min)compared with normal activity. Together, these results suggest that caution is required when the bone shaft bending strength index is used to reconstruct the activity levels of past humans.
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Affiliation(s)
- Ian J Wallace
- Department of Anthropology, Stony Brook University, Stony Brook, NY, USA
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Kular J, Tickner JC, Pavlos NJ, Viola HM, Abel T, Lim BS, Yang X, Chen H, Cook R, Hool LC, Zheng MH, Xu J. Choline kinase β mutant mice exhibit reduced phosphocholine, elevated osteoclast activity, and low bone mass. J Biol Chem 2014; 290:1729-42. [PMID: 25451916 DOI: 10.1074/jbc.m114.567966] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The maintenance of bone homeostasis requires tight coupling between bone-forming osteoblasts and bone-resorbing osteoclasts. However, the precise molecular mechanism(s) underlying the differentiation and activities of these specialized cells are still largely unknown. Here, we identify choline kinase β (CHKB), a kinase involved in the biosynthesis of phosphatidylcholine, as a novel regulator of bone homeostasis. Choline kinase β mutant mice (flp/flp) exhibit a systemic low bone mass phenotype. Consistently, osteoclast numbers and activity are elevated in flp/flp mice. Interestingly, osteoclasts derived from flp/flp mice exhibit reduced sensitivity to excessive levels of extracellular calcium, which could account for the increased bone resorption. Conversely, supplementation of cytidine 5'-diphosphocholine in vivo and in vitro, a regimen that bypasses CHKB deficiency, restores osteoclast numbers to physiological levels. Finally, we demonstrate that, in addition to modulating osteoclast formation and function, loss of CHKB corresponds with a reduction in bone formation by osteoblasts. Taken together, these data posit CHKB as a new modulator of bone homeostasis.
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Affiliation(s)
- Jasreen Kular
- From the School of Pathology and Laboratory Medicine
| | | | | | | | - Tamara Abel
- Centre for Microscopy, Characterization and Analysis, University of Western Australia, Nedlands 6009, Western Australia, Australia and
| | - Bay Sie Lim
- From the School of Pathology and Laboratory Medicine
| | - Xiaohong Yang
- the Guangzhou Institute of Traumatic Surgery, the Fourth Affiliated Hospital of Medical College, Jinan University, Guangzhou 510182, China
| | - Honghui Chen
- the Guangzhou Institute of Traumatic Surgery, the Fourth Affiliated Hospital of Medical College, Jinan University, Guangzhou 510182, China
| | - Robert Cook
- From the School of Pathology and Laboratory Medicine
| | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, and
| | | | - Jiake Xu
- From the School of Pathology and Laboratory Medicine,
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Ozcivici E, Judex S. Trabecular bone recovers from mechanical unloading primarily by restoring its mechanical function rather than its morphology. Bone 2014; 67:122-9. [PMID: 24857858 DOI: 10.1016/j.bone.2014.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
Upon returning to normal ambulatory activities, the recovery of trabecular bone lost during unloading is limited. Here, using a mouse population that displayed a large range of skeletal susceptibility to unloading and reambulation, we tested the impact of changes in trabecular bone morphology during unloading and reambulation on its simulated mechanical properties. Female adult mice from a double cross of BALB/cByJ and C3H/HeJ strains (n=352) underwent 3wk of hindlimb unloading followed by 3wk of reambulation. Normally ambulating mice served as controls (n=30). As quantified longitudinally by in vivo μCT, unloading led to an average loss of 43% of trabecular bone volume fraction (BV/TV) in the distal femur. Finite element models of the μCT tomographies showed that deterioration of the trabecular structure raised trabecular peak Von-Mises (PVM) stresses on average by 27%, indicating a significant increase in the risk of mechanical failure compared to baseline. Further, skewness of the Von-Mises stress distributions (SVM) increased by 104% with unloading, indicating that the trabecular structure became inefficient in resisting the applied load. During reambulation, bone of experimental mice recovered on average only 10% of its lost BV/TV. Even though the addition of trabecular tissue was small during reambulation, PVM and SVM as indicators of risk of mechanical failure decreased by 56% and 57%, respectively. Large individual differences in the response of trabecular bone, together with a large sample size, facilitated stratification of experimental mice based on the level of recovery. As a fraction of all mice, 66% of the population showed some degree of recovery in BV/TV while in 89% and 87% of all mice, PVM and SVM decreased during reambulation, respectively. At the end of the reambulation phase, only 8% of the population recovered half of the unloading induced losses in BV/TV while 50% and 49% of the population recovered half of the unloading induced deterioration in PVM and SVM, respectively. The association between morphological and mechanical variables was strong at baseline but progressively decreased during the unloading and reambulation cycles. The preferential recovery of trabecular micromechanical properties over bone volume fraction emphasizes that mechanical demand during reambulation does not, at least initially, seek to restore bone's morphology but its mechanical integrity.
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Affiliation(s)
- Engin Ozcivici
- Department of Mechanical Engineering, Izmir Institute of Technology, Urla, Izmir, Turkey; Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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Ozcivici E, Zhang W, Donahue LR, Judex S. Quantitative trait loci that modulate trabecular bone's risk of failure during unloading and reloading. Bone 2014; 64:25-32. [PMID: 24698783 DOI: 10.1016/j.bone.2014.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 02/01/2014] [Accepted: 03/22/2014] [Indexed: 01/23/2023]
Abstract
Genetic makeup of an individual is a strong determinant of the morphologic and mechanical properties of bone. Here, in an effort to identify quantitative trait loci (QTLs) for changes in the simulated mechanical parameters of trabecular bone during altered mechanical demand, we subjected 352 second generation female adult (16 weeks old) BALBxC3H mice to 3 weeks of hindlimb unloading followed by 3 weeks of reambulation. Longitudinal in vivo microcomputed tomography (μCT) scans tracked trabecular changes in the distal femur. Tomographies were directly translated into finite element (FE) models and subjected to a uniaxial compression test. Apparent trabecular stiffness and components of the Von Mises (VM) stress distributions were computed for the distal metaphysis and associated with QTLs. At baseline, five QTLs explained 20% of the variation in trabecular peak stresses across the mouse population. During unloading, three QTLs accounted for 14% of the variability in peak stresses. During reambulation, one QTL accounted for 5% of the variability in peak stresses. QTLs were also identified for mechanically induced changes in stiffness, median stress values and skewness of stress distributions. There was little overlap between QTLs identified for baseline and QTLs for longitudinal changes in mechanical properties, suggesting that distinct genes may be responsible for the mechanical response of trabecular bone. Unloading related QTLs were also different from reambulation related QTLs. Further, QTLs identified here for mechanical properties differed from previously identified QTLs for trabecular morphology, perhaps revealing novel gene targets for reducing fracture risk in individuals exposed to unloading and for maximizing the recovery of trabecular bone's mechanical properties during reambulation.
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Affiliation(s)
- Engin Ozcivici
- Department of Mechanical Engineering, Izmir Institute of Technology, Urla, Izmir 35430, Turkey.
| | | | | | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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Swift JM, Lima F, Macias BR, Allen MR, Greene ES, Shirazi-Fard Y, Kupke JS, Hogan HA, Bloomfield SA. Partial weight bearing does not prevent musculoskeletal losses associated with disuse. Med Sci Sports Exerc 2014; 45:2052-60. [PMID: 23657172 DOI: 10.1249/mss.0b013e318299c614] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The purpose of this study was to investigate whether partial weight-bearing activity, at either one-sixth or one-third of body mass, blunts the deleterious effects of simulated microgravity (0G) after 21 d on muscle mass and quantitative/qualitative measures of bone. METHODS Using a novel, previously validated partial weight-bearing suspension device, mice were subjected to 16% (G/3, i.e., simulated lunar gravity) or 33% (G/6, i.e., simulated Martian gravity) weight bearing for 21 d. One gravity control (1G, i.e., Earth gravity) and tail-suspended mice (0G, i.e., simulated microgravity) served as controls to compare the effects of simulated lunar and Martian gravity to both Earth and microgravity. RESULTS Simulated microgravity (0G) resulted in an 8% reduction in body mass and a 28% lower total plantarflexor muscle mass (for both, P < 0.01) as compared with 1G controls, but one-sixth and one-third partial weight-bearing activity attenuated losses. Relative to 1G controls, trabecular bone volume fraction (-9% to -13%) and trabecular thickness (-10% to -14%) were significantly lower in all groups (P < 0.01). In addition, cancellous and cortical bone formation rates (BFR) were lower in all reduced weight-bearing groups compared with 1G controls (-46% to -57%, trabecular BFR; -73% to -85%, cortical BFR; P < 0.001). Animals experiencing one-third but not one-sixth weight bearing exhibited attenuated deficits in femoral neck mechanical strength associated with 0G. CONCLUSION These results suggest that partial weight bearing (up to 33% of body mass) is not sufficient to protect against bone loss observed with simulated 0 g but does mitigate reductions in soleus mass in skeletally mature female mice.
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Affiliation(s)
- Joshua M Swift
- 1Department of Health and Kinesiology, Texas A&M University, College Station, TX; 2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN; 3Department of Biomedical Engineering, Texas A&M University, College Station, TX; 4Department of Mechanical Engineering, Texas A&M University, College Station, TX; and 5Department of Nutrition and Food Science, Texas A&M University, College Station, TX
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Ausk BJ, Huber P, Srinivasan S, Bain SD, Kwon RY, McNamara EA, Poliachik SL, Sybrowsky CL, Gross TS. Metaphyseal and diaphyseal bone loss in the tibia following transient muscle paralysis are spatiotemporally distinct resorption events. Bone 2013; 57:413-22. [PMID: 24063948 PMCID: PMC3865853 DOI: 10.1016/j.bone.2013.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/23/2013] [Accepted: 09/11/2013] [Indexed: 11/25/2022]
Abstract
When the skeleton is catabolically challenged, there is great variability in the timing and extent of bone resorption observed at cancellous and cortical bone sites. It remains unclear whether this resorptive heterogeneity, which is often evident within a single bone, arises from increased permissiveness of specific sites to bone resorption or localized resorptive events of varied robustness. To explore this question, we used the mouse model of calf paralysis induced bone loss, which results in metaphyseal and diaphyseal bone resorption of different timing and magnitude. Given this phenotypic pattern of resorption, we hypothesized that bone loss in the proximal tibia metaphysis and diaphysis occurs through resorption events that are spatially and temporally distinct. To test this hypothesis, we undertook three complimentary in vivo/μCT imaging studies. Specifically, we defined spatiotemporal variations in endocortical bone resorption during the 3weeks following calf paralysis, applied a novel image registration approach to determine the location where bone resorption initiates within the proximal tibia metaphysis, and explored the role of varied basal osteoclast activity on the magnitude of bone loss initiation in the metaphysis using μCT based bone resorption parameters. A differential response of metaphyseal and diaphyseal bone resorption was observed throughout each study. Acute endocortical bone loss following muscle paralysis occurred almost exclusively within the metaphyseal compartment (96.5% of total endocortical bone loss within 6days). Using our trabecular image registration approach, we further resolved the initiation of metaphyseal bone loss to a focused region of significant basal osteoclast function (0.03mm(3)) adjacent to the growth plate. This correlative observation of paralysis induced bone loss mediated by basal growth plate cell dynamics was supported by the acute metaphyseal osteoclastic response of 5-week vs. 13-month-old mice. Specifically, μCT based bone resorption rates normalized to initial trabecular surface (BRRBS) were 3.7-fold greater in young vs. aged mice (2.27±0.27μm(3)/μm(2)/day vs. 0.60±0.44μm(3)/μm(2)/day). In contrast to the focused bone loss initiation in the metaphysis, diaphyseal bone loss initiated homogeneously throughout the long axis of the tibia predominantly in the second week following paralysis (81.3% of diaphyseal endocortical expansion between days 6 and 13). The timing and homogenous nature are consistent with de novo osteoclastogenesis mediating the diaphyseal resorption. Taken together, our data suggests that tibial metaphyseal and diaphyseal bone loss induced by transient calf paralysis are spatially and temporally discrete events. In a broader context, these findings are an essential first step toward clarifying the timing and origins of multiple resorptive events that would require targeting to fully inhibit bone loss following neuromuscular trauma.
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Affiliation(s)
- Brandon J Ausk
- Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
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Daegling DJ, Granatosky MC, McGraw WS. Ontogeny of material stiffness heterogeneity in the macaque mandibular corpus. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 153:297-304. [PMID: 24282152 DOI: 10.1002/ajpa.22432] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 11/10/2022]
Abstract
Evidence is accumulating that bone material stiffness increases during ontogeny, and the role of elastic modulus in conditioning attributes of strength and toughness is therefore a focus of ongoing investigation. Developmental changes in structural properties of the primate mandible have been documented, but comparatively little is known about changes in material heterogeneity and their impact on biomechanical behavior. We examine a cross-sectional sample of Macaca fascicularis (N = 14) to investigate a series of hypotheses that collectively evaluate whether the patterning of material stiffness (elastic modulus) heterogeneity in the mandible differs among juvenile, subadult and adult individuals. Because differences in age-related activity patterns are known to influence bone stiffness and strength, these data are potentially useful for understanding the relationship between feeding behavior on the one hand and material and structural properties of the mandible on the other. Elastic modulus is shown to be spatially dependent regardless of age, with this dependence being explicable primarily by differences in alveolar versus basal cortical bone. Elastic modulus does not differ consistently between buccal and lingual cortical plates, despite likely differences in the biomechanical milieu of these regions. Since we found only weak support for the hypothesis that the spatial patterning of heterogeneity becomes more predictable with age, accumulated load history may not account for regional differences in bone material properties in mature individuals with respect to the mandibular corpus.
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Affiliation(s)
- David J Daegling
- Department of Anthropology, 1112 Turlington Hall, University of Florida, Gainesville, FL, 32611
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Judex S, Zhang W, Donahue LR, Ozcivici E. Genetic loci that control the loss and regain of trabecular bone during unloading and reambulation. J Bone Miner Res 2013; 28:1537-49. [PMID: 23401066 DOI: 10.1002/jbmr.1883] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 01/15/2013] [Accepted: 01/23/2013] [Indexed: 12/18/2022]
Abstract
Changes in trabecular morphology during unloading and reloading are marked by large variations between individuals, implying that there is a strong genetic influence on the magnitude of the response. Here, we subjected more than 350 second-generation (BALBxC3H) 4-month-old adult female mice to 3 weeks of hindlimb unloading followed by 3 weeks of reambulation to identify the quantitative trait loci (QTLs) that define an individual's propensity to either lose trabecular bone when weight bearing is removed or to gain trabecular bone when weight bearing is reintroduced. Longitudinal in vivo micro-computed tomography (µCT) scans demonstrated that individual mice lost between 15% and 71% in trabecular bone volume fraction (BV/TV) in the distal femur during unloading (average: -43%). Changes in trabecular BV/TV during the 3-week reambulation period ranged from a continuation of bone loss (-18%) to large additions (56%) of tissue (average: +10%). During unloading, six QTLs accounted for 21% of the total variability in changes in BV/TV whereas one QTL accounted for 6% of the variability in changes in BV/TV during reambulation. QTLs were also identified for changes in trabecular architecture. Most of the QTLs defining morphologic changes during unloading or reambulation did not overlap with those QTLs identified at baseline, suggesting that these QTLs harbor genes that are specific for sensing changes in the levels of weight bearing. The lack of overlap in QTLs between unloading and reambulation also emphasizes that the genes modulating the trabecular response to unloading are distinct from those regulating tissue recovery during reloading. The identified QTLs contain the regulatory genes underlying the strong genetic regulation of trabecular bone's sensitivity to weight bearing and may help to identify individuals that are most susceptible to unloading-induced bone loss and/or the least capable of recovering.
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Affiliation(s)
- Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
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Wang H, Ji B, Liu XS, van Oers RFM, Guo XE, Huang Y, Hwang KC. Osteocyte-viability-based simulations of trabecular bone loss and recovery in disuse and reloading. Biomech Model Mechanobiol 2013; 13:153-66. [DOI: 10.1007/s10237-013-0492-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 04/02/2013] [Indexed: 11/28/2022]
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Chan ME, Uzer G, Rubin CT. The potential benefits and inherent risks of vibration as a non-drug therapy for the prevention and treatment of osteoporosis. Curr Osteoporos Rep 2013; 11:36-44. [PMID: 23371467 PMCID: PMC3586310 DOI: 10.1007/s11914-012-0132-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The delivery of mechanical signals to the skeleton using vibration is being considered as a non-drug treatment of osteoporosis. Delivered over a range of magnitudes and frequencies, vibration has been shown to be both anabolic and anti-catabolic to the musculoskeletal tissues, yet caution must be emphasized as these mechanical signals, particularly chronic exposure to higher intensities, is a known pathogen to many physiological systems. In contrast, accumulating preclinical and clinical evidence indicates that low intensity vibration (LIV) improves bone quality through regulating the activity of cells responsible for bone remodeling, as well as biasing the differentiation fate of their mesenchymal and hematopoietic stem cell progenitors. In vitro studies provide insights into the biologic mechanisms of LIV, and indicate that cells respond to these low magnitude signals through a distinct mechanism driven not by matrix strain but acceleration. These cell, animal, and human studies may represent the foundation of a safe, non-drug means to protect and improve the musculoskeletal system of the elderly, injured, and infirmed.
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Affiliation(s)
- M Ete Chan
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA,
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Medalha CC, Amorim BO, Fernandes KR, Pereira RM, Renno ACM, Ribeiro DA. Temporal modifications in bone following spinal cord injury in rats. Arch Med Sci 2012; 8:1102-7. [PMID: 23319988 PMCID: PMC3542503 DOI: 10.5114/aoms.2012.32424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 03/18/2012] [Accepted: 04/07/2012] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION The aim of this study was to investigate the temporal modifications in bone mass, bone biomechanical properties and bone morphology in spinal cord injured rats 2, 4 and 6 weeks after a transection. MATERIAL AND METHODS Control animals were randomly distributed into four groups (n = 10 each group): control group (CG) - control animals sacrificed immediately after surgery; spinal cord-injured 2 weeks (2W) - spinal cord-injured animals sacrificed 2 weeks after surgery; spinal cord-injured 4 weeks (4W) - spinal cord-injured animals sacrificed 4 weeks after surgery; spinal cord-injured 6 weeks (6W) - spinal cord-injured animals sacrificed 6 weeks after surgery. RESULTS Biomechanical properties of the right tibia were determined by a three-point bending test and injured animals showed a statistically significant decrease in maximal load compared to control animals. The right femur was used for densitometric analysis and bone mineral content of the animals sacrificed 4 and 6 weeks after surgery was significantly higher compared to the control animals and animals sacrificed 2 weeks after surgery. Histopathological and morphological analysis of tibiae revealed intense resorptive areas in the group 2 weeks after injury only. CONCLUSIONS The results of this study show that this rat model is a valuable tool to investigate bone remodeling processes specifically associated with SCI. Taken together, our results suggest that spinal cord injury induced bone loss within 2 weeks after injury in rats.
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Affiliation(s)
| | | | | | - Rosa Maria Pereira
- Rheumatology Division, School of Medicine, University of São Paulo, Brazil
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Lloyd SA, Bandstra ER, Willey JS, Riffle SE, Tirado-Lee L, Nelson GA, Pecaut MJ, Bateman TA. Effect of proton irradiation followed by hindlimb unloading on bone in mature mice: a model of long-duration spaceflight. Bone 2012; 51:756-64. [PMID: 22789684 PMCID: PMC3601666 DOI: 10.1016/j.bone.2012.07.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 06/29/2012] [Accepted: 07/02/2012] [Indexed: 11/21/2022]
Abstract
Bone loss associated with microgravity unloading is well documented; however, the effects of spaceflight-relevant types and doses of radiation on the skeletal system are not well defined. In addition, the combined effect of unloading and radiation has not received much attention. In the present study, we investigated the effect of proton irradiation followed by mechanical unloading via hindlimb suspension (HLS) in mice. Sixteen-week-old female C57BL/6 mice were either exposed to 1 Gy of protons or a sham irradiation procedure (n=30/group). One day later, half of the mice in each group were subjected to four weeks of HLS or normal loading conditions. Radiation treatment alone (IRR) resulted in approximately 20% loss of trabecular bone volume fraction (BV/TV) in the tibia and femur, with no effect in the cortical bone compartment. Conversely, unloading induced substantially greater loss of both trabecular bone (60-70% loss of BV/TV) and cortical bone (approximately 20% loss of cortical bone volume) in both the tibia and femur, with corresponding decreases in cortical bone strength. Histological analyses and serum chemistry data demonstrated increased levels of osteoclast-mediated bone resorption in unloaded mice, but not IRR. HLS+IRR mice generally experienced greater loss of trabecular bone volume fraction, connectivity density, and trabecular number than either unloading or irradiation alone. Although the duration of unloading may have masked certain effects, the skeletal response to irradiation and unloading appears to be additive for certain parameters. Appropriate modeling of the environmental challenges of long duration spaceflight will allow for a better understanding of the underlying mechanisms mediating spaceflight-associated bone loss and for the development of effective countermeasures.
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Affiliation(s)
- Shane A. Lloyd
- Division of Musculoskeletal Sciences, Department of Orthopaedics and Rehabilitation, Penn State College of Medicine, 500 University Drive, Hershey, PA, USA, 17033
| | - Eric R. Bandstra
- Department of Bioengineering, Clemson University, 501 Rhodes Research Center, Clemson, SC, USA, 29634
| | - Jeffrey S. Willey
- Section of Molecular Medicine and Department of Radiation Oncology, Comprehensive Cancer Center, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA, 27157
| | - Stephanie E. Riffle
- Department of Bioengineering, Clemson University, 501 Rhodes Research Center, Clemson, SC, USA, 29634
| | - Leidamarie Tirado-Lee
- Department of Bioengineering, Clemson University, 501 Rhodes Research Center, Clemson, SC, USA, 29634
| | - Gregory A. Nelson
- Department of Radiation Medicine, Loma Linda University and Medical Center, 11234 Anderson Street Loma Linda, CA, USA, 92354
| | - Michael J. Pecaut
- Department of Radiation Medicine, Loma Linda University and Medical Center, 11234 Anderson Street Loma Linda, CA, USA, 92354
| | - Ted A. Bateman
- Departments of Biomedical Engineering and Radiation Oncology, University of North Carolina at Chapel Hill, 152 MacNider Hall, Chapel Hill, NC, USA, 27599
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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.
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Affiliation(s)
- David Karasik
- Faculty of Medicine in the Galilee, Bar-Ilan University Safed, Israel
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Wang H, Ji B, Liu XS, Guo XE, Huang Y, Hwang KC. Analysis of microstructural and mechanical alterations of trabecular bone in a simulated three-dimensional remodeling process. J Biomech 2012; 45:2417-25. [PMID: 22867764 DOI: 10.1016/j.jbiomech.2012.06.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 04/17/2012] [Accepted: 06/28/2012] [Indexed: 11/19/2022]
Abstract
Bone remodeling is a complex dynamic process, which modulates both bone mass and bone microstructure. In addition to bone mass, bone microstructure is an important contributor to bone quality in osteoporosis and fragility fractures. However, the quantitative knowledge of evolution of three-dimensional (3D) trabecular microstructure in adaptation to the external forces is currently limited. In this study, a new 3D simulation method of remodeling of human trabecular bone was developed to quantitatively study the dynamic evolution of bone mass and trabecular microstructure in response to different external loading conditions. The morphological features of trabecular plate and rod, such as thickness and number density in different orientations were monitored during the remodeling process using a novel imaging analysis technique, namely Individual Trabecula Segmentation (ITS). We showed that the volume fraction and microstructures of trabecular bone including, trabecular type and orientation, were determined by the applied mechanical load. Particularly, the morphological parameters of trabecular plates were more sensitive to the applied load, indicating that they played the major role in the mechanical properties of the trabecular bone. Reducing the applied load caused severe microstructural deteriorations of trabecular bone, such as trabecular plate perforation, rod breakage, and a conversion from plates to rods.
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Affiliation(s)
- Hong Wang
- Department of Engineering Mechanics, School of Aerospace, Tsinghua University, Beijing 100084, China
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Musculoskeletal changes following non-invasive knee injury using a novel mouse model of post-traumatic osteoarthritis. Osteoarthritis Cartilage 2012; 20:773-82. [PMID: 22531459 DOI: 10.1016/j.joca.2012.04.014] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 04/02/2012] [Accepted: 04/13/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Post-traumatic osteoarthritis (PTOA) is a common consequence of traumatic joint injury, with 50% of anterior cruciate ligament (ACL) rupture patients developing PTOA within 10-20 years. Currently accepted mouse models of PTOA initiate symptoms using various methods, none of which faithfully mimic clinically-relevant injury conditions. In this study we characterize a novel non-invasive mouse model of PTOA that injures the ACL with a single load of tibial compression overload. We utilize this model to determine the time course of articular cartilage and subchondral bone changes following knee injury. DESIGN Mice were euthanized 1, 3, 7, 14, 28, or 56 days after non-invasive knee injury. Knees were scanned using micro-computed tomography (μCT) in order to quantify subchondral trabecular bone, subchondral bone plate, and non-native bone formation (heterotopic ossification). Development of osteoarthritis (OA) was graded using the osteoarthritis research society international (OARSI) scale on histological sections of injured and uninjured knees. RESULTS Following injury we observed a rapid loss of trabecular bone in injured knees compared to uninjured knees by 7 days post-injury, followed by a partial recovery of trabecular bone to a new steady state by 28 days post-injury. We also observed considerable non-native bone formation by 56 days post-injury. Grading of histological sections revealed deterioration of articular cartilage by 56 days post-injury, consistent with development of mild OA. CONCLUSIONS This study establishes a novel mouse model of PTOA, and describes the time course of musculoskeletal changes following knee injury, helping to establish the window of opportunity for preventative treatment.
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Gupta S, Vijayaraghavan S, Uzer G, Judex S. Multiple exposures to unloading decrease bone's responsivity but compound skeletal losses in C57BL/6 mice. Am J Physiol Regul Integr Comp Physiol 2012; 303:R159-67. [PMID: 22592559 DOI: 10.1152/ajpregu.00499.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A single exposure to mechanical unloading can result in significant bone loss, but the consequences of multiple exposures are largely unknown. Within a 18-wk period, adult C57BL/6 male mice were exposed to 2 wk of hindlimb unloading (HLU) followed by 4 wk of reambulation (RA) once (1x-HLU), twice (2x-HLU), or three times (3x-HLU), or served as ambulatory age-matched controls. In vivo μCT longitudinally tracked changes in trabecular and cortical compartments of the femur. Normally ambulating control mice experienced significant age-related loss in trabecular bone volume fraction throughout the course of the experiment. This loss was compounded by HLU with 2x- and 3x-HLU mice experiencing a 27% and 24% greater reduction in trabecular bone and a 60% and 63% inhibition of age-related trabecular thickening. The recovery of cortical bone was also incomplete during each 4-wk RA period and, at completion of the experiment, cortical area in 3x-HLU mice was 5% smaller than in control and 1x-HLU. When eliminating age as a confounding variable, comparison between individual HLU/RA cycles showed that the magnitude of the response diminished during subsequent exposures. The extent of trabecular thinning in mice unloaded for the first time was 1.6-fold greater than the second time and nearly twofold greater than the third time. Similarly, the increase in trabecular thickness during the first RA cycle was twofold greater than during the second and third RA cycle. Together, our data demonstrate that even though multiple exposures to mechanical unloading are more detrimental than a single unloading period, bone's mechanosensitivity is reduced with consecutive unloading/reambulation cycles.
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Affiliation(s)
- Shikha Gupta
- Integrative Skeletal Adaptation and Genetics Laboratory, Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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Manske SL, Good CA, Zernicke RF, Boyd SK. High-frequency, low-magnitude vibration does not prevent bone loss resulting from muscle disuse in mice following botulinum toxin injection. PLoS One 2012; 7:e36486. [PMID: 22590551 PMCID: PMC3349718 DOI: 10.1371/journal.pone.0036486] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 04/09/2012] [Indexed: 11/18/2022] Open
Abstract
High-frequency, low-magnitude vibration enhances bone formation ostensibly by mimicking normal postural muscle activity. We tested this hypothesis by examining whether daily exposure to low-magnitude vibration (VIB) would maintain bone in a muscle disuse model with botulinum toxin type A (BTX). Female 16–18 wk old BALB/c mice (N = 36) were assigned to BTX-VIB, BTX-SHAM, VIB, or SHAM. BTX mice were injected with BTX (20 µL; 1 U/100 g body mass) into the left hindlimb posterior musculature. All mice were anaesthetized for 20 min/d, 5 d/wk, for 3 wk, and the left leg mounted to a holder. Through the holder, VIB mice received 45 Hz, ±0.6 g sinusoidal acceleration without weight bearing. SHAM mice received no vibration. At baseline and 3 wk, muscle cross-sectional area (MCSA) and tibial bone properties (epiphysis, metaphysis and diaphysis) were assessed by in vivo micro-CT. Bone volume fraction in the metaphysis decreased 12±9% and 7±6% in BTX-VIB and BTX-SHAM, but increased in the VIB and SHAM. There were no differences in dynamic histomorphometry outcomes between BTX-VIB and BTX nor between VIB and SHAM. Thus, vibration did not prevent bone loss induced by a rapid decline in muscle activity nor produce an anabolic effect in normal mice. The daily loading duration was shorter than would be expected from postural muscle activity, and may have been insufficient to prevent bone loss. Based on the approach used in this study, vibration does not prevent bone loss in the absence of muscle activity induced by BTX.
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MESH Headings
- Animals
- Bone Diseases, Metabolic/chemically induced
- Bone Diseases, Metabolic/pathology
- Bone Diseases, Metabolic/physiopathology
- Bone Diseases, Metabolic/therapy
- Botulinum Toxins, Type A/adverse effects
- Botulinum Toxins, Type A/pharmacology
- Female
- Mice
- Mice, Inbred BALB C
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Disorders, Atrophic/chemically induced
- Muscular Disorders, Atrophic/pathology
- Muscular Disorders, Atrophic/physiopathology
- Muscular Disorders, Atrophic/therapy
- Neurotoxins/adverse effects
- Neurotoxins/pharmacology
- Physical Therapy Modalities
- Tibia/pathology
- Tibia/physiopathology
- Vibration
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Affiliation(s)
- Sarah L. Manske
- Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Schulich School of Engineering, University of Calgary, Calgary, Canada
| | - Craig A. Good
- Schulich School of Engineering, University of Calgary, Calgary, Canada
| | - Ronald F. Zernicke
- Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Faculty of Medicine, University of Calgary, Calgary, Canada
- Departments of Orthopaedic Surgery and Biomedical Engineering and School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
| | - Steven K. Boyd
- Schulich School of Engineering, University of Calgary, Calgary, Canada
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