101
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Hikita A, Iimura T, Oshima Y, Saitou T, Yamamoto S, Imamura T. Analyses of bone modeling and remodeling using in vitro reconstitution system with two-photon microscopy. Bone 2015; 76:5-17. [PMID: 25771421 DOI: 10.1016/j.bone.2015.02.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/31/2015] [Accepted: 02/19/2015] [Indexed: 11/24/2022]
Abstract
Bone modeling and remodeling are cellular events during which osteoblast lineage cells and osteoclasts interact. During these events, cells undergo drastic changes with time as they become differentiated. Their morphology, topology, and activity are affected by other cells and the extracellular matrices. Since the mechanisms underlying the cellular events of bone metabolism have not been elucidated, there is a need for systems to analyze these cellular networks and their microenvironments spatiotemporally at the cellular level. Here we report a novel in vitro system for reconstituting the bone cell network of osteoclasts, osteoblasts, and osteocytes in the mineralized nodule, allowing for observation of bone modeling and remodeling phenomena by 2-photon microscopy. Using this system, the change in morphology of osteoblasts from cuboidal to flat cells was observed and measured during the formation of mineralized nodules. Furthermore, the recruitment of osteoblasts to resorption pits and their replenishment by newly formed matrices were successfully observed, providing strong evidence for the coupling of bone resorption and bone formation at cellular level. During such remodeling cycle, flat osteoblasts that survived more than 7 weeks were recruited to resorption pits, where they became cuboidal osteoblasts that express osteocalcin. This novel system permitted the elucidation of cellular behavior during bone modeling and remodeling, and can be used to analyze cellular events involved in bone metabolism.
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Affiliation(s)
- Atsuhiko Hikita
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Ehime, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Ehime, Japan; Division of Bio-imaging, Proteo-Science Center, Ehime University, Ehime, Japan; Department of Cartilage & Bone Regeneration (Fujisoft), Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
| | - Tadahiro Iimura
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Ehime, Japan; Division of Bio-imaging, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Yusuke Oshima
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Ehime, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Ehime, Japan; Division of Bio-imaging, Proteo-Science Center, Ehime University, Ehime, Japan; Translational Research Center, Ehime University Hospital, Ehime, Japan
| | - Takashi Saitou
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Ehime, Japan; Translational Research Center, Ehime University Hospital, Ehime, Japan
| | - Shin Yamamoto
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Ehime, Japan; Department of Gastroenterology and Metabiology, Ehime University, Ehime, Japan
| | - Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Ehime, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Ehime, Japan; Division of Bio-imaging, Proteo-Science Center, Ehime University, Ehime, Japan; Translational Research Center, Ehime University Hospital, Ehime, Japan.
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102
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Abstract
Adding to its well-known roles in locomotion and calcium balance, the skeleton has recently been appreciated as a true endocrine organ. Bone remodeling, a highly dynamic process, requires synchronized activities and crosstalk between bone cells. Discovery and characterization of the Wnt/β catenin pathway in bone formation, FGF23 regulation of phosphate homeostasis and osteocalcin in energy and glucose homeostasis have reframed our view of the skeleton from simply a target tissue of the endocrine system to an endocrine tissue itself. This comprehensive review provides an overview of these complex pathways, their application to human bone disorders and implications for developing diagnostic and therapeutic targets.
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Affiliation(s)
- Anda Gonciulea
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
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103
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Andreasen CM, Ding M, Overgaard S, Bollen P, Andersen TL. A reversal phase arrest uncoupling the bone formation and resorption contributes to the bone loss in glucocorticoid treated ovariectomised aged sheep. Bone 2015; 75:32-9. [PMID: 25689083 DOI: 10.1016/j.bone.2015.02.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/09/2015] [Indexed: 01/08/2023]
Abstract
Large animals as sheep are often used as models for human osteoporosis. Our aim was therefore to determine how glucocorticoid treatment of ovariectomised sheep affects the cancellous bone, determining the cellular events within the bone remodelling process that contributes to their bone loss. Twenty female sheep were assigned for two groups; an untreated control group and an ovariectomised group treated with glucocorticoids (0.6 mg/kg/day, 5 times weekly) for 7 months. At 7 months the glucocorticoid-treated ovariectomised sheep showed a significant change in the bone microstructure revealed by a decreased trabecular bone volume and thickness compared to the control sheep. The treatment led to a temporary elevation of the bone resorption marker CTX (c-terminal collagen telopeptide), while the bone formation marker osteocalcin remained suppressed all 7 months. Histomorphometrically, the treated sheep had a complete absence of osteoid surfaces, and a 5-fold increase in the extent of eroded/reversal surfaces after 7 months. Most of these reversal surfaces were actually arrested reversal surfaces, defined as reversal surfaces without the presence of neighbouring osteoid surfaces or osteoclasts, which is classically observed next to active reversal surfaces. As in humans, these arrested reversal surfaces had compared to active reversal surfaces a reduced canopy coverage, a significantly decreased cell density, and a decreased immunoreactivity for the osteoblastic markers osterix, runx2 and smooth muscle actin in the mononuclear reversal cells colonising the surfaces. In conclusion, glucocorticoid treatment of ovariectomised sheep induced a significant bone loss, caused by an arrest of the reversal phase, resulting in an uncoupling of the bone formation and resorption during the reversal phase, as recently demonstrated in postmenopausal women with glucocorticoid-induced osteoporosis. This supports the relevance of the sheep model to the pathophysiology of glucocorticoid-induced osteoporosis in postmenopausal women, making it a relevant preclinical model for orthopaedic implant and biomaterial research.
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Affiliation(s)
- Christina M Andreasen
- Orthopaedic Research Laboratory, Department of Orthopaedics and Traumatology O, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J. B. Winsloewsvej 15 ground floor, DK-5000 Odense C, Denmark.
| | - Ming Ding
- Orthopaedic Research Laboratory, Department of Orthopaedics and Traumatology O, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J. B. Winsloewsvej 15 ground floor, DK-5000 Odense C, Denmark.
| | - Søren Overgaard
- Orthopaedic Research Laboratory, Department of Orthopaedics and Traumatology O, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J. B. Winsloewsvej 15 ground floor, DK-5000 Odense C, Denmark.
| | - Peter Bollen
- Biomedical Laboratory, University of Southern Denmark, J. B. Winsloewsvej 23, DK-5000 Odense C, Denmark.
| | - Thomas L Andersen
- Department of Clinical Cell Biology (KCB), Vejle Hospital - Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Vejle, Kabbeltoft 25, DK-7100 Vejle, Denmark.
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104
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Erben RG. Hypothesis: Coupling between Resorption and Formation in Cancellous bone Remodeling is a Mechanically Controlled Event. Front Endocrinol (Lausanne) 2015; 6:82. [PMID: 26052311 PMCID: PMC4440405 DOI: 10.3389/fendo.2015.00082] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/05/2015] [Indexed: 11/13/2022] Open
Abstract
Coupling is the process that links bone resorption to formation in a temporally and spatially coordinated manner within the remodeling cycle. In order to maintain skeletal integrity, it is of crucial importance that the amount of bone resorbed matches the amount of newly formed bone in each remodeling site. Although a number of different explanatory models have been developed, the mechanisms that couple bone resorption and formation in bone remodeling are still a matter of controversy. Here, I propose a model in which coupling is achieved by biomechanical strain sensed by osteocytes within the newly built bone package. In this model, the resorption cavity created by osteoclasts results in mechanical weakening of the structural element, and, thus, in increased strain under constant loading conditions. Subsequent bone formation is initiated by strain-sensitive osteocytes in the underlying bone matrix. After osteoblastic bone formation has started, the newly built osteocyte-osteoblast network detects strain. Once the mechanical strain within the newly built bone structural unit falls below a certain threshold, bone formation stops. In this biomechanical strain-driven model, osteoblasts do not need to "know" how much bone was previously resorbed in a given site. In addition, this model does not require the transfer of any information from bone-resorbing osteoclasts to bone-forming osteoblasts, because biomechanical strain "guides" osteoblasts through their job of re-filling the resorption cavity.
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Affiliation(s)
- Reinhold G. Erben
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
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105
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Jensen PR, Andersen TL, Hauge EM, Bollerslev J, Delaissé JM. A joined role of canopy and reversal cells in bone remodeling--lessons from glucocorticoid-induced osteoporosis. Bone 2015; 73:16-23. [PMID: 25497571 DOI: 10.1016/j.bone.2014.12.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/19/2014] [Accepted: 12/04/2014] [Indexed: 12/18/2022]
Abstract
Successful bone remodeling demands that osteoblasts restitute the bone removed by osteoclasts. In human cancellous bone, a pivotal role in this restitution is played by the canopies covering the bone remodeling surfaces, since disruption of canopies in multiple myeloma, postmenopausal- and glucocorticoid-induced osteoporosis is associated with the absence of progression of the remodeling cycle to bone formation, i.e., uncoupling. An emerging concept explaining this critical role of canopies is that they represent a reservoir of osteoprogenitors to be delivered to reversal surfaces. In postmenopausal osteoporosis, this concept is supported by the coincidence between the absence of canopies and scarcity of cells on reversal surfaces together with abortion of the remodeling cycle. Here we tested whether this concept holds true in glucocorticoid-induced osteoporosis. A histomorphometric analysis of iliac crest biopsies from patients exposed to long-term glucocorticoid treatment revealed a subpopulation of reversal surfaces corresponding to the characteristics of arrest found in postmenopausal osteoporosis. Importantly, these arrested reversal surfaces were devoid of canopy coverage in almost all biopsies, and their prevalence correlated with a deficiency in bone forming surfaces. Taken together with the other recent data, the functional link between canopies, reversal surface activity, and the extent of bone formation surface in postmenopausal- and glucocorticoid-induced osteoporosis, supports a model where bone restitution during remodeling demands recruitment of osteoprogenitors from the canopy onto reversal surfaces. These data suggest that securing the presence of functional local osteoprogenitors deserves attention in the search of strategies to prevent the bone loss that occurs during bone remodeling in pathological situations.
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Affiliation(s)
- Pia Rosgaard Jensen
- Department of Clinical Cell Biology (KCB), Vejle Hospital, IRS, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark.
| | - Thomas Levin Andersen
- Department of Clinical Cell Biology (KCB), Vejle Hospital, IRS, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark
| | - Ellen-Margrethe Hauge
- Department of Rheumatology, Aarhus University Hospital, Building 3, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Jens Bollerslev
- Section of Specialized Endocrinology, Medical Clinic B, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Jean-Marie Delaissé
- Department of Clinical Cell Biology (KCB), Vejle Hospital, IRS, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark
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106
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Coluzzi F, Pergolizzi J, Raffa RB, Mattia C. The unsolved case of "bone-impairing analgesics": the endocrine effects of opioids on bone metabolism. Ther Clin Risk Manag 2015; 11:515-23. [PMID: 25848298 PMCID: PMC4386765 DOI: 10.2147/tcrm.s79409] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The current literature describes the possible risks for bone fracture in chronic analgesics users. There are three main hypotheses that could explain the increased risk of fracture associated with central analgesics, such as opioids: 1) the increased risk of falls caused by central nervous system effects, including sedation and dizziness; 2) reduced bone mass density caused by the direct opioid effect on osteoblasts; and 3) chronic opioid-induced hypogonadism. The impact of opioids varies by sex and among the type of opioid used (less, for example, for tapentadol and buprenorphine). Opioid-associated androgen deficiency is correlated with an increased risk of osteoporosis; thus, despite that standards have not been established for monitoring and treating opioid-induced hypogonadism or hypoadrenalism, all patients chronically taking opioids (particularly at doses ≥100 mg morphine daily) should be monitored for the early detection of hormonal impairment and low bone mass density.
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Affiliation(s)
- Flaminia Coluzzi
- Department of Medical and Surgical Sciences and Biotechnologies, Unit of Anesthesiology, Intensive Care Medicine and Pain Therapy, Faculty of Pharmacy and Medicine - Polo Pontino, Sapienza University of Rome, Latina, Italy ; SIAARTI Study Group on Acute and Chronic Pain, Rome, Italy
| | - Joseph Pergolizzi
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Naples Anesthesia and Pain Associates, Naples, FL, USA
| | - Robert B Raffa
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, PA, USA
| | - Consalvo Mattia
- Department of Medical and Surgical Sciences and Biotechnologies, Unit of Anesthesiology, Intensive Care Medicine and Pain Therapy, Faculty of Pharmacy and Medicine - Polo Pontino, Sapienza University of Rome, Latina, Italy ; SIAARTI Study Group on Acute and Chronic Pain, Rome, Italy
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107
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108
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Du YY, Zhao YX, Liu YP, Liu W, Wang MM, Yuan CM. Regulatory Tweak/Fn14 signaling pathway as a potent target for controlling bone loss. Biomed Pharmacother 2015; 70:170-3. [PMID: 25776497 DOI: 10.1016/j.biopha.2015.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/04/2015] [Indexed: 01/17/2023] Open
Abstract
Metabolic bone diseases, such as rheumatoid arthritis (RA) and osteoporosis, are characterized as imbalance between bone formation and bone resorption, leading to bone microarchitecture damage and bone mineral density loss. Bone loss is huge threat for older people's health, which imposes a heavy financial burden on patients and their families. However, the effectiveness of bone loss treatment in clinical practice is limited. With the understanding of the molecular and cellular regulators and mediators of bone remodelling, we know that some signaling pathways and inflammatory cytokines play important roles in the development of RA and osteoporosis. The increasing evidence showed that tumor necrosis factor (TNF)-like weak inducer of apoptosis (Tweak)/fibroblast growth factor-inducible 14 (Fn14) signalling controls a variety of cellular activities in biological processes, such as proliferation, differentiation, and apoptosis and has diverse biological functions in pathological mechanisms like inflammation that are associated with the process of bone metabolism. Recent studies suggest that the interactions between Tweak/Fn14 play critical roles in osteoblast and osteoclast differentiation and apoptosis, especially in those rheumatoid arthritis patients. These findings suggest that interventions targeting Tweak/Fn14 signaling pathway to regulate osteoblast-osteoclast coupling according to its biological effects, which results in promoting osteoblast formation and inhibiting osteoclast resorption, may be a promising approach for bone loss prevention and treatment in the near future.
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Affiliation(s)
- Yan-Ying Du
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China
| | - Yan-Xia Zhao
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China
| | - Yu-Ping Liu
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China.
| | - Wei Liu
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China
| | - Ming-Ming Wang
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China
| | - Chong-Ming Yuan
- Department of Trauma Orthopedics, Tengzhou Central People's Hospital, Shandong, PR China
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109
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Sims NA, Martin TJ. Coupling Signals between the Osteoclast and Osteoblast: How are Messages Transmitted between These Temporary Visitors to the Bone Surface? Front Endocrinol (Lausanne) 2015; 6:41. [PMID: 25852649 PMCID: PMC4371744 DOI: 10.3389/fendo.2015.00041] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 03/10/2015] [Indexed: 01/19/2023] Open
Affiliation(s)
- Natalie A. Sims
- Department of Medicine, St. Vincent’s Institute of Medical Research, St. Vincent’s Hospital, The University of Melbourne, Fitzroy, VIC, Australia
- *Correspondence:
| | - T. John Martin
- Department of Medicine, St. Vincent’s Institute of Medical Research, St. Vincent’s Hospital, The University of Melbourne, Fitzroy, VIC, Australia
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110
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Gruber R. Molecular and cellular basis of bone resorption. Wien Med Wochenschr 2014; 165:48-53. [PMID: 25223736 DOI: 10.1007/s10354-014-0310-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 10/24/2022]
Abstract
Osteoclast research has an exciting history and a challenging future. More than 3 decades ago, it became evident that bone-resorbing osteoclasts are of hematopoietic origin and are ultimately linked to the "basic multicellular unit," where they team up with the other cell types, including bone-forming osteoblasts. Since 2 decades, we have learned about the signaling pathways controlling genes relevant for osteoclastogenesis and bone resorption. It took another decade until the hypothesized "osteoclast differentiation" factor was discovered and was translated into an approved pharmacologic strategy. Here, the focus is on another molecular target, cathepsin K, a cysteine protease being released by the osteoclast into the resorption compartment. Genetic deletion and pharmacological blocking of cathepsin K reduces bone resorption but with ongoing bone formation. This observation not only holds great promise to become a new pharmacologic strategy, but it also provides new insights into the coordinated work of cells in the "basic multicellular unit" and thus, bridges the history and future of osteoclast research. This article is a short primer on osteoclast biology for readers of the special issue on odanacatib, a cathepsin K inhibitor.
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Affiliation(s)
- Reinhard Gruber
- Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010, Bern, Switzerland,
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