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Cunningham HC, Orr S, Murugesh DK, Hsia AW, Osipov B, Go L, Wu PH, Wong A, Loots GG, Kazakia GJ, Christiansen BA. Differential bone adaptation to mechanical unloading and reloading in young, old, and osteocyte deficient mice. Bone 2023; 167:116646. [PMID: 36529445 PMCID: PMC10077944 DOI: 10.1016/j.bone.2022.116646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Mechanical unloading causes rapid loss of bone structure and strength, which gradually recovers after resuming normal loading. However, it is not well established how this adaptation to unloading and reloading changes with age. Clinically, elderly patients are more prone to musculoskeletal injury and longer periods of bedrest, therefore it is important to understand how periods of disuse will affect overall skeletal health of aged subjects. Bone also undergoes an age-related decrease in osteocyte density, which may impair mechanoresponsiveness. In this study, we examined bone adaptation during unloading and subsequent reloading in mice. Specifically, we examined the differences in bone adaptation between young mice (3-month-old), old mice (18-month-old), and transgenic mice that exhibit diminished osteocyte density at a young age (3-month-old BCL-2 transgenic mice). Mice underwent 14 days of hindlimb unloading followed by up to 14 days of reloading. We analyzed trabecular and cortical bone structure in the femur, mechanical properties of the femoral cortical diaphysis, osteocyte density and cell death in cortical bone, and serum levels of inflammatory cytokines. We found that young mice lost ~10% cortical bone volume and 27-42% trabecular bone volume during unloading and early reloading, with modest recovery of metaphyseal trabecular bone and near total recovery of epiphyseal trabecular bone, but no recovery of cortical bone after 14 days of reloading. Old mice lost 12-14% cortical bone volume and 35-50% trabecular bone volume during unloading and early reloading but had diminished recovery of trabecular bone during reloading and no recovery of cortical bone. In BCL-2 transgenic mice, no cortical bone loss was observed during unloading or reloading, but 28-31% trabecular bone loss occurred during unloading and early reloading, with little to no recovery during reloading. No significant differences in circulating inflammatory cytokine levels were observed due to unloading and reloading in any of the experimental groups. These results illustrate important differences in bone adaptation in older and osteocyte deficient mice, suggesting a possible period of vulnerability in skeletal health in older subjects during and following a period of disuse that may affect skeletal health in elderly patients.
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Affiliation(s)
- Hailey C Cunningham
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America
| | - Sophie Orr
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America
| | - Deepa K Murugesh
- Lawrence Livermore National Laboratory, 7000 East Avenue, L-452, Livermore, CA 94550, United States of America
| | - Allison W Hsia
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America
| | - Benjamin Osipov
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America
| | - Lauren Go
- University of California San Francisco, Department of Radiology & Biomedical Imaging, 185 Berry Street, Bldg B, San Francisco, CA 94158, United States of America
| | - Po Hung Wu
- University of California San Francisco, Department of Radiology & Biomedical Imaging, 185 Berry Street, Bldg B, San Francisco, CA 94158, United States of America
| | - Alice Wong
- University of California Davis, School of Veterinary Medicine, 1285 Veterinary Medicine Dr, Bldg VM3A, Rm 4206, Davis, CA 95616, United States of America
| | - Gabriela G Loots
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America; Lawrence Livermore National Laboratory, 7000 East Avenue, L-452, Livermore, CA 94550, United States of America
| | - Galateia J Kazakia
- University of California San Francisco, Department of Radiology & Biomedical Imaging, 185 Berry Street, Bldg B, San Francisco, CA 94158, United States of America
| | - Blaine A Christiansen
- University of California Davis Health, Department of Orthopaedic Surgery, 2700 Stockton Blvd, Suite 2301, Sacramento, CA 95817, United States of America.
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Babu LK, Ghosh D. Looking at Mountains: Role of Sustained Hypoxia in Regulating Bone Mineral Homeostasis in Relation to Wnt Pathway and Estrogen. Clin Rev Bone Miner Metab 2022. [DOI: 10.1007/s12018-022-09283-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Simulation on bone remodeling with stochastic nature of adult and elderly using topology optimization algorithm. J Biomech 2022; 136:111078. [DOI: 10.1016/j.jbiomech.2022.111078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 11/20/2022]
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Bjørklund G, Dadar M, Aaseth J, Chirumbolo S. Thymosin β4: A Multi-Faceted Tissue Repair Stimulating Protein in Heart Injury. Curr Med Chem 2021; 27:6294-6305. [PMID: 31333080 DOI: 10.2174/0929867326666190716125456] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 12/16/2022]
Abstract
Thymosin Beta-4 (Tβ4) is known as a major pleiotropic actin-sequestering protein that is involved in tumorigenesis. Tβ4 is a water-soluble protein that has different promising clinical applications in the remodeling and ulcerated tissues repair following myocardial infarction, stroke, plasticity and neurovascular remodeling of the Peripheral Nervous System (PNS) and the Central Nervous System (CNS). On the other hand, similar effects have been observed for Tβ4 in other kinds of tissues, including cardiac muscle tissue. In recent reports, as it activates resident epicardial progenitor cells and modulates inflammatory-caused injuries, Tβ4 has been suggested as a promoter of the survival of cardiomyocytes. Furthermore, Tβ4 may act in skeletal muscle and different organs in association/synergism with numerous other tissue repair stimulating factors, including melatonin and C-fiber-derived peptides. For these reasons, the present review highlights the promising role of Tβ4 in cardiac healing.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway,Inland Norway University of Applied Sciences, Elverum, Norway
| | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences,
University of Verona, Verona, Italy
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Montesi M, Jähn K, Bonewald L, Stea S, Bordini B, Beraudi A. Hypoxia mediates osteocyte ORP150 expression and cell death in vitro. Mol Med Rep 2016; 14:4248-4254. [DOI: 10.3892/mmr.2016.5790] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/07/2016] [Indexed: 11/05/2022] Open
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Barney LE, Jansen LE, Polio SR, Galarza S, Lynch ME, Peyton SR. The Predictive Link between Matrix and Metastasis. Curr Opin Chem Eng 2016; 11:85-93. [PMID: 26942108 DOI: 10.1016/j.coche.2016.01.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cancer spread (metastasis) is responsible for 90% of cancer-related fatalities. Informing patient treatment to prevent metastasis, or kill all cancer cells in a patient's body before it becomes metastatic is extremely powerful. However, aggressive treatment for all non-metastatic patients is detrimental, both for quality of life concerns, and the risk of kidney or liver-related toxicity. Knowing when and where a patient has metastatic risk could revolutionize patient treatment and care. In this review, we attempt to summarize the key work of engineers and quantitative biologists in developing strategies and model systems to predict metastasis, with a particular focus on cell interactions with the extracellular matrix (ECM), as a tool to predict metastatic risk and tropism.
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Affiliation(s)
- L E Barney
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003
| | - L E Jansen
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003
| | - S R Polio
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003
| | - S Galarza
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003
| | - M E Lynch
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003; Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst Amherst, MA 01003
| | - S R Peyton
- Department of Chemical Engineering, University of Massachusetts, Amherst Amherst, MA 01003
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Abstract
Cells actively sense the mechanical properties of the extracellular matrix, such as its rigidity, morphology, and deformation. The cell-matrix interaction influences a range of cellular processes, including cell adhesion, migration, and differentiation, among others. This article aims to review some of the recent progress that has been made in modeling mechanosensing in cell-matrix interactions at different length scales. The issues discussed include specific interactions between proteins, the structure and mechanosensitivity of focal adhesions, the cluster effects of the specific binding, the structure and behavior of stress fibers, cells' sensing of substrate stiffness, and cell reorientation on cyclically stretched substrates. The review concludes by looking toward future opportunities in the field and at the challenges to understanding active cell-matrix interactions.
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Affiliation(s)
- Bin Chen
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China;
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A threshold of mechanical strain intensity for the direct activation of osteoblast function exists in a murine maxilla loading model. Biomech Model Mechanobiol 2015; 15:1091-100. [PMID: 26578077 DOI: 10.1007/s10237-015-0746-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
Abstract
The response to the mechanical loading of bone tissue has been extensively investigated; however, precisely how much strain intensity is necessary to promote bone formation remains unclear. Combination studies utilizing histomorphometric and numerical analyses were performed using the established murine maxilla loading model to clarify the threshold of mechanical strain needed to accelerate bone formation activity. For 7 days, 191 kPa loading stimulation for 30 min/day was applied to C57BL/6J mice. Two regions of interest, the AWAY region (away from the loading site) and the NEAR region (near the loading site), were determined. The inflammatory score increased in the NEAR region, but not in the AWAY region. A strain intensity map obtained from [Formula: see text] images was superimposed onto the images of the bone formation inhibitor, sclerostin-positive cell localization. The number of sclerostin-positive cells significantly decreased after mechanical loading of more than [Formula: see text] in the AWAY region, but not in the NEAR region. The mineral apposition rate, which shows the bone formation ability of osteoblasts, was accelerated at the site of surface strain intensity, namely around [Formula: see text], but not at the site of lower surface strain intensity, which was around [Formula: see text] in the AWAY region, thus suggesting the existence of a strain intensity threshold for promoting bone formation. Taken together, our data suggest that a threshold of mechanical strain intensity for the direct activation of osteoblast function and the reduction of sclerostin exists in a murine maxilla loading model in the non-inflammatory region.
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Buenzli PR, Sims NA. Quantifying the osteocyte network in the human skeleton. Bone 2015; 75:144-50. [PMID: 25708054 DOI: 10.1016/j.bone.2015.02.016] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/25/2015] [Accepted: 02/10/2015] [Indexed: 11/26/2022]
Abstract
Osteocytes form an extensive cellular network throughout the hard tissue matrix of the skeleton, which is known to regulate skeletal structure. However due to limitations in imaging techniques, the magnitude and complexity of this network remain undefined. We have used data from recent papers obtained by new imaging techniques, in order to estimate absolute and relative quantities of the human osteocyte network and form a more complete understanding of the extent and nature of this network. We estimate that the total number of osteocytes within the average adult human skeleton is ~42 billion and that the total number of osteocyte dendritic projections from these cells is ~3.7 trillion. Based on prior measurements of canalicular density and a mathematical model of osteocyte dendritic process branching, we calculate that these cells form a total of 23 trillion connections with each other and with bone surface cells. We estimate the total length of all osteocytic processes connected end-to-end to be 175,000 km. Furthermore, we calculate that the total surface area of the lacuno-canalicular system is 215 m(2). However, the residing osteocytes leave only enough space for 24 mL of extracellular fluid. Calculations based on measurements in lactation-induced murine osteocytic osteolysis indicate a potential total loss of ~16,000 mm(3) (16 mL) of bone by this process in the human skeleton. Finally, based on the average speed of remodelling in the adult, we calculate that 9.1 million osteocytes are replenished throughout the skeleton on a daily basis, indicating the dynamic nature of the osteocyte network. We conclude that the osteocyte network is a highly complex communication network, and is much more vast than commonly appreciated. It is at the same order of magnitude as current estimates of the size of the neural network in the brain, even though the formation of the branched network differs between neurons and osteocytes. Furthermore, continual replenishment of large numbers of osteocytes in the process of remodelling allows therapeutic changes to the continually renewed osteoblast population to be rapidly incorporated into the skeleton.
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Affiliation(s)
- Pascal R Buenzli
- School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Natalie A Sims
- St Vincent's Institute of Medical Research, The University of Melbourne, Fitzroy, VIC 3065, Australia.
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Osteocytes as a record of bone formation dynamics: A mathematical model of osteocyte generation in bone matrix. J Theor Biol 2015; 364:418-27. [DOI: 10.1016/j.jtbi.2014.09.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/17/2014] [Indexed: 11/23/2022]
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Klika V, Pérez MA, García-Aznar JM, Maršík F, Doblaré M. A coupled mechano-biochemical model for bone adaptation. J Math Biol 2013; 69:1383-429. [DOI: 10.1007/s00285-013-0736-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 10/04/2013] [Indexed: 01/08/2023]
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