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Li C, Fennessy P. The periosteum: a simple tissue with many faces, with special reference to the antler-lineage periostea. Biol Direct 2021; 16:17. [PMID: 34663443 PMCID: PMC8522104 DOI: 10.1186/s13062-021-00310-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 11/30/2022] Open
Abstract
Periosteum is a thin membrane covering bone surfaces and consists of two layers: outer fibrous layer and inner cambium layer. Simple appearance of periosteum has belied its own complexity as a composite structure for physical bone protection, mechano-sensor for sensing mechanical loading, reservoir of biochemical molecules for initiating cascade signaling, niche of osteogenic cells for bone formation and repair, and "umbilical cord" for nourishing bone tissue. Periosteum-derived cells (PDCs) have stem cell attributes: self-renewal (no signs of senescence until 80 population doublings) and multipotency (differentiate into fibroblasts, osteoblasts, chondrocytes, adipocytes and skeletal myocytes). In this review, we summarized the currently available knowledge about periosteum and with special references to antler-lineage periostea, and demonstrated that although periosteum is a type of simple tissue in appearance, with multiple faces in functions; antler-lineage periostea add another dimension to the properties of somatic periostea: capable of initiation of ectopic organ formation upon transplantation and full mammalian organ regeneration when interacted with the covering skin. Very recently, we have translated this finding into other mammals, i.e. successfully induced partial regeneration of the amputated rat legs. We believe further refinement along this line would greatly benefit human health.
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Affiliation(s)
- Chunyi Li
- Institute of Antler Science and Product Technology, Changchun Sci-Tech University, 1345 Pudong Rd., Changchun, 130000, Jilin, China.
| | - Peter Fennessy
- AbacusBio Limited, 442 Moray Place, Dunedin, New Zealand
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Lanske B, Chandler H, Pierce A, Brown J, Ominsky M, Kostenuik P, Hattersley G. Abaloparatide, a PTH receptor agonist with homology to PTHrP, enhances callus bridging and biomechanical properties in rats with femoral fracture. J Orthop Res 2019; 37:812-820. [PMID: 30790359 DOI: 10.1002/jor.24254] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/29/2019] [Indexed: 02/04/2023]
Abstract
Fractures typically heal via endochondral and intramembranous bone formation, which together form a callus that achieves union and biomechanical recovery. PTHrP, a PTH receptor agonist, plays an important physiological role in fracture healing as an endogenous stimulator of endochondral and intramembranous bone formation. Abaloparatide, a novel systemically-administered osteoanabolic PTH receptor agonist that reduces fracture risk in women with postmenopausal osteoporosis, has 76% homology to PTHrP, suggesting it may have potential to improve fracture healing. To test this hypothesis, ninety-six 12-week-old male rats underwent unilateral internally-stabilized closed mid-diaphyseal femoral fractures and were treated starting the next day with daily s.c. saline (Vehicle) or abaloparatide at 5 or 20 µg/kg/d for 4 or 6 weeks (16 rats/group/time point). Histomorphometry and histology analyses indicated that fracture calluses from the abaloparatide groups exhibited significantly greater total area, higher fluorescence scores indicating more newly-formed bone, and higher fracture bridging scores versus Vehicle controls. Callus bridging score best correlated with callus cartilage score (r = 0.64) and fluorescence score (r = 0.67) at week 4, and callus area correlated with cartilage score (r = 0.60) and fluorescence score (r = 0.89) at Week 6. By micro-CT, calluses from one or both abaloparatide groups had greater bone volume, bone volume fraction, bone mineral content, bone mineral density, and cross-sectional area at both time points versus Vehicle controls. Destructive bending tests indicated greater callus maximum load and stiffness in one or both abaloparatide groups at both time points versus Vehicle controls. These results provide preliminary preclinical evidence for improved fracture healing with systemically-administered abaloparatide. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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Affiliation(s)
- Beate Lanske
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
| | - Heidi Chandler
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
| | - Allen Pierce
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
| | - Jeffery Brown
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
| | - Michael Ominsky
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
| | - Paul Kostenuik
- University of Michigan School of Dentistry, Phylon Pharma Services, Newbury Park, California
| | - Gary Hattersley
- Radius Health Inc., 950 Winter Street, Waltham, Massachusetts
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Liu H, Su H, Wang X, Hao W. MiR-148a regulates bone marrow mesenchymal stem cells-mediated fracture healing by targeting insulin-like growth factor 1. J Cell Biochem 2019; 120:1350-1361. [PMID: 30335895 DOI: 10.1002/jcb.27121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/04/2018] [Indexed: 01/24/2023]
Abstract
The purpose of this study was to investigate the underlying molecular mechanisms of fracture healing mediated by bone marrow mesenchymal stem cells. Differentially expressed microRNAs in acutely injured subjects and healthy volunteers were screened by microarray analysis. The dual luciferase reporter system was used to verify whether insulin-like growth factor 1 (IGF1) was the direct target gene regulated by miR-148a. The expression level of miR-148a and IGF1 after osteogenic differentiation was detected by quantitative real-time polymerase chain reaction. Western blot was used to determine the protein expression of bone markers, including IGF1, runt-related transcription factor 2 (Runx2), osteocalcin, and osteopontin in rat bone marrow-derived mesenchymal stem cells. Alkaline phosphatase and alizarin red staining was used to detect alkaline phosphatase activity and calcium deposition. An animal fracture model was used for in vivo experiments. MiR-148a was highly expressed in acutely injured subjects compared with healthy volunteers, and IGF1 was a target of miR-148a. Moreover, compared with the negative control group, IGF1 messenger RNA expression was significantly increased in the miR-148a antagomir group. During osteogenic differentiation, the expression of IGF1, Runx2, osteocalcin, and osteopontin was higher in the miR-148a antagomir group than other groups. In vivo experiments further confirmed that upregulation of IGF1 enhanced fracture healing efficiently by decreasing callus width and area and improving bone mineral density, maximum load, stiffness, and energy absorption. It was proved that IGF1 was the direct target gene of miR-148a, and the use of rat bone marrow-derived mesenchymal stem cells with low expression of miR-148a could improve fracture healing by upregulating IGF1.
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Affiliation(s)
- Hongzhi Liu
- Department of Orthopaedics and Traumatology, The Affiliated Yaitai Yuhuangding Hospital of Qingdao University Medical College, Yantai, Shandong, China
| | - Hao Su
- Department of Orthopaedics and Traumatology, The Affiliated Yaitai Yuhuangding Hospital of Qingdao University Medical College, Yantai, Shandong, China
| | - Xin Wang
- Department of Orthopaedics and Traumatology, The Affiliated Yaitai Yuhuangding Hospital of Qingdao University Medical College, Yantai, Shandong, China
| | - Wei Hao
- Department of Orthopaedics and Traumatology, The Affiliated Yaitai Yuhuangding Hospital of Qingdao University Medical College, Yantai, Shandong, China
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Midha S, Chawla S, Chakraborty J, Chameettachal S, Ghosh S. Differential Regulation of Hedgehog and Parathyroid Signaling in Mulberry and Nonmulberry Silk Fibroin Textile Braids. ACS Biomater Sci Eng 2018; 4:595-607. [DOI: 10.1021/acsbiomaterials.7b00874] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Swati Midha
- Regenerative Engineering
Laboratory, Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India 110016
| | - Shikha Chawla
- Regenerative Engineering
Laboratory, Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India 110016
| | - Juhi Chakraborty
- Regenerative Engineering
Laboratory, Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India 110016
| | - Shibu Chameettachal
- Regenerative Engineering
Laboratory, Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India 110016
| | - Sourabh Ghosh
- Regenerative Engineering
Laboratory, Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India 110016
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5
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Wang Y, Fang X, Wang C, Ding C, Lin H, Liu A, Wang L, Cao Y. Exogenous PTHrP Repairs the Damaged Fracture Healing of PTHrP+/- Mice and Accelerates Fracture Healing of Wild Mice. Int J Mol Sci 2017; 18:ijms18020337. [PMID: 28178186 PMCID: PMC5343872 DOI: 10.3390/ijms18020337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 01/29/2017] [Accepted: 02/01/2017] [Indexed: 01/08/2023] Open
Abstract
Bone fracture healing is a complicated physiological regenerative process initiated in response to injury and is similar to bone development. To demonstrate whether an exogenous supply of parathyroid hormone–related protein (PTHrP) helps in bone fracture healing, closed mid-diaphyseal femur fractures were created and stabilized with intramedullary pins in eight-week-old wild-type (WT) PTHrP+/+ and PTHrP+/− mice. After administering PTHrP for two weeks, callus tissue properties were analyzed at one, two, and four weeks post-fracture (PF) by various methods. Bone formation–related genes and protein expression levels were evaluated by real-time reverse transcriptase–polymerase chain reaction and Western blots. At two weeks PF, mineral density of callus, bony callus areas, mRNA levels of alkaline phosphatase (ALP), type I collagen, Runt-related transcription factor 2 (Runx-2), and protein levels of Runx-2 and insulin-like growth factor-1 decreased in PTHrP+/− mice compared with WT mice. At four weeks PF, total collagen-positive bony callus areas, osteoblast number, ALP-positive areas, and type I collagen-positive areas all decreased in PTHrP+/− mice. At both two and four weeks PF, tartrate-resistant acid phosphatase–positive osteoclast number and surface decreased a little in PTHrP+/− mice. The study indicates that exogenous PTHrP provided by subcutaneous injection could redress impaired bone fracture healing, leading to mutation of activated PTHrP by influencing callus areas, endochondral bone formation, osteoblastic bone formation, and bone turnover.
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Affiliation(s)
- Yinhe Wang
- Department of Orthopaedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Xin Fang
- Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden.
| | - Chun Wang
- Department of Geriatrics, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Congzhu Ding
- Department of Geriatrics, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Hua Lin
- Department of Orthopaedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Anlong Liu
- Department of Orthopaedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Lei Wang
- Department of Oral & Maxillofacial-Head & Neck Oncology, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai 200011, China.
| | - Yang Cao
- Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden.
- Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro 70182, Sweden.
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Kostenuik P, Mirza FM. Fracture healing physiology and the quest for therapies for delayed healing and nonunion. J Orthop Res 2017; 35:213-223. [PMID: 27743449 PMCID: PMC6120140 DOI: 10.1002/jor.23460] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/07/2016] [Indexed: 02/04/2023]
Abstract
Delayed healing and nonunion of fractures represent enormous burdens to patients and healthcare systems. There are currently no approved pharmacological agents for the treatment of established nonunions, or for the acceleration of fracture healing, and no pharmacological agents are approved for promoting the healing of closed fractures. Yet several pharmacologic agents have the potential to enhance some aspects of fracture healing. In preclinical studies, various agents working across a broad spectrum of molecular pathways can produce larger, denser and stronger fracture calluses. However, untreated control animals in most of these studies also demonstrate robust structural and biomechanical healing, leaving unclear how these interventions might alter the healing of recalcitrant fractures in humans. This review describes the physiology of fracture healing, with a focus on aspects of natural repair that may be pharmacologically augmented to prevent or treat delayed or nonunion fractures (collectively referred to as DNFs). The agents covered in this review include recombinant BMPs, PTH/PTHrP receptor agonists, activators of Wnt/β-catenin signaling, and recombinant FGF-2. Agents from these therapeutic classes have undergone extensive preclinical testing and progressed to clinical fracture healing trials. Each can promote bone formation, which is important for the stability of bridged calluses, and some but not all can also promote cartilage formation, which may be critical for the initial bridging and subsequent stabilization of fractures. Appropriately timed stimulation of chondrogenesis and osteogenesis in the fracture callus may be a more effective approach for preventing or treating DNFs compared with stimulation of osteogenesis alone. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:213-223, 2017.
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Affiliation(s)
- Paul Kostenuik
- School of DentistryUniversity of MichiganPhylon Pharma ServicesNewbury ParkCalifornia
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7
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Wang T, Zhang X, Bikle DD. Osteogenic Differentiation of Periosteal Cells During Fracture Healing. J Cell Physiol 2016; 232:913-921. [PMID: 27731505 DOI: 10.1002/jcp.25641] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 10/07/2016] [Indexed: 12/15/2022]
Abstract
Five to ten percent of fractures fail to heal normally leading to additional surgery, morbidity, and altered quality of life. Fracture healing involves the coordinated action of stem cells primarily coming from the periosteum which differentiate into the chondrocytes and osteoblasts, forming first the soft (cartilage) callus followed by the hard (bone) callus. These stem cells are accompanied by a vascular invasion that appears critical for the differentiation process and which may enable the entry of osteoclasts necessary for the remodeling of the callus into mature bone. However, more research is needed to clarify the signaling events that activate the osteochondroprogenitor cells of periosteum and stimulate their differentiation into chondrocytes and osteoblasts. Ultimately a thorough understanding of the mechanisms for differential regulation of these osteochondroprogenitors will aid in the treatment of bone healing and the prevention of delayed union and nonunion of fractures. In this review, evidence supporting the concept that the periosteal cells are the major cell sources of skeletal progenitors for the fracture callus will be discussed. The osteogenic differentiation of periosteal cells manipulated by Wnt/β-catenin, TGF/BMP, Ihh/PTHrP, and IGF-1/PI3K-Akt signaling in fracture repair will be examined. The effect of physical (hypoxia and hyperoxia) and chemical factors (reactive oxygen species) as well as the potential coordinated regulatory mechanisms in the periosteal progenitor cells promoting osteogenic differentiation will also be discussed. Understanding the regulation of periosteal osteochondroprogenitors during fracture healing could provide insight into possible therapeutic targets and thereby help to enhance future fracture healing and bone tissue engineering approaches. J. Cell. Physiol. 232: 913-921, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Tao Wang
- Center for Musculoskeletal Research, School of Medicine and Dentistry, University of Rochester, Rochester, New York.,Endocrine Unit, VA Medical Center and University of California, San Francisco, California
| | - Xinping Zhang
- Center for Musculoskeletal Research, School of Medicine and Dentistry, University of Rochester, Rochester, New York
| | - Daniel D Bikle
- Endocrine Unit, VA Medical Center and University of California, San Francisco, California
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Torgomyan A, Adamyan S, Ghambaryan H, Hasratyan H, Khudaverdyan D, Archer C. Effect of parathyroid hormone on prechondroblast differentiation. CYTOL GENET+ 2016. [DOI: 10.3103/s0095452716050145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Polyzos SA, Anastasilakis AD, Kountouras J, Makras P, Papatheodorou A, Kokkoris P, Sakellariou GT, Terpos E. Circulating sclerostin and Dickkopf-1 levels in patients with nonalcoholic fatty liver disease. J Bone Miner Metab 2016; 34:447-56. [PMID: 26056025 DOI: 10.1007/s00774-015-0687-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/09/2015] [Indexed: 12/12/2022]
Abstract
There is increasing evidence for bone-liver interplay. The main aim of this study was to determine serum sclerostin and Dickkopf (DKK)-1 levels in patients with nonalcoholic fatty liver disease (NAFLD) and their association with the disease severity. Patients with biopsy-proven NAFLD, 13 with nonalcoholic simple steatosis (SS) and 14 with steatohepatitis (NASH), and 20 gender-, age-, body mass index- and waist circumference-matched controls were enrolled. Serum sclerostin, DKK-1, bone turnover markers, vitamin D, insulin and standard biochemical and hematologic parameters were measured; lumbar spinal dual-energy X-ray absorptiometry was performed. We observed that there was a progressive decline in serum sclerostin levels from the controls (76.1 ± 6.8) to SS (53.5 ± 6.4) and NASH (46.0 ± 8.1 pmol/l) patients (p = 0.009); in adjusted pairwise comparisons, sclerostin was significantly higher in the controls than in NASH patients (p = 0.012). Although serum DKK-1 did not differ between groups (p = 0.135), there was a trend toward U-shaped distribution (controls 35.8 ± 2.8; SS 27.3 ± 2.9; NASH 36.8 ± 4.4 pmol/l). Higher DKK-1 levels were independently associated with NASH. Regarding specific histological lesions, DKK-1 levels were marginally lower in NAFLD patients with lower (≤33 %) than higher (>33 %) steatosis grade (27.7 ± 3.1 and 38.8 ± 4.7 pmol/l, respectively; p = 0.049). No other significant difference was observed within histological lesions. In conclusion, serum sclerostin levels were lower in NASH patients than in controls. DKK-1 levels were independently associated with NASH in NAFLD patients. The potential importance of these findings indicates a possible bone-liver interaction and warrants further investigation.
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Affiliation(s)
- Stergios A Polyzos
- Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 13 Simou Lianidi, 551 34, Thessaloniki, Macedonia, Greece.
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | | | - Jannis Kountouras
- Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 13 Simou Lianidi, 551 34, Thessaloniki, Macedonia, Greece
| | - Polyzois Makras
- Department of Endocrinology and Diabetes, 251 Hellenic Air Force and VA General Hospital, Athens, Greece
| | | | - Panagiotis Kokkoris
- Department of Medical Research, 251 Hellenic Air Force and VA General Hospital, Athens, Greece
| | | | - Evangelos Terpos
- Department of Clinical Therapeutics, University of Athens School of Medicine, Athens, Greece
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Kato A, Suzuki M, Karasawa Y, Sugimoto T, Doi K. Histopathological Study of Time Course Changes in PTHrP-Induced Incisor Lesions of Rats. Toxicol Pathol 2016; 33:230-8. [PMID: 15902966 DOI: 10.1080/01926230590906530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Parathyroid hormone related peptide (PTHrP) was discovered as a causative factor of humoral hypercalcemia of malignancy (HHM). In the present study using HHM model rats, the time course of odontoblastic response to PTHrP and its relation to incisal fracture were elicited. Nude rats were implanted with PTHrP-expressing tumor (LC-6) cells, mandibular incisors were collected at several time points. Microscopically 3 distinctive types of odontoblastic/dentin lesions were observed. Hypercalcfied dentin, which was reported as hypercalcemia-induced lesion in previous reports, observed in all areas of the dentin from week 5–10 samplings. Dentin niche, observed solely in week-10 sampling point, exhibited a nature identical to that of reparative odontoblast reported in the literatures of various cytotoxic agents. Since cytotoxicites were neither observed prior to the lesions nor reported as a role of PTHrP, the reparative response may have derived from highly sustained levels of PTHrP. Loss of columnar odontoblasts height was initially observed at week-5 time point in the middle section of the incisor. This primary loss of cell height prior to incisor fracture was considered to be the earliest response to the increased PTHrP levels of this model.
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Affiliation(s)
- Atsuhiko Kato
- Toxicology Laboratory, Chugai Pharmaceutical Co., Ltd., Gotemba-shi, Shizuoka 412-8513, Japan.
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Kunimoto T, Okubo N, Minami Y, Fujiwara H, Hosokawa T, Asada M, Oda R, Kubo T, Yagita K. A PTH-responsive circadian clock operates in ex vivo mouse femur fracture healing site. Sci Rep 2016; 6:22409. [PMID: 26926165 PMCID: PMC4772627 DOI: 10.1038/srep22409] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 02/12/2016] [Indexed: 01/10/2023] Open
Abstract
The circadian clock contains clock genes including Bmal1 and Period2, and it maintains an interval rhythm of approximately 24 hours (the circadian rhythm) in various organs including growth plate and articular cartilage. As endochondral ossification is involved not only in growth plate but also in fracture healing, we investigated the circadian clock functions in fracture sites undergoing healing. Our fracture models using external fixation involved femurs of Period2::Luciferase knock-in mice which enables the monitoring of endogenous circadian clock state via bioluminescence. Organ culture was performed by collecting femurs, and fracture sites were observed using bioluminescence imaging systems. Clear bioluminescence rhythms of 24-hour intervals were revealed in fracture healing sites. When parathyroid hormone (PTH) was administered to fractured femurs in organ culture, peak time of Period2::Luciferase activity in fracture sites and growth plates changed, indicating that PTH-responsive circadian clock functions in the mouse femur fracture healing site. While PTH is widely used in treating osteoporosis, many studies have reported that it contributes to improvement of fracture healing. Future studies of the role of this local clock in wound healing may reveal a novel function of the circadian timing mechanism in skeletal cells.
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Affiliation(s)
- Tatsuya Kunimoto
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Musculoskeletal Chronobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Naoki Okubo
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Musculoskeletal Chronobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoichi Minami
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Musculoskeletal Chronobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiroyoshi Fujiwara
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshihiro Hosokawa
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Musculoskeletal Chronobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Maki Asada
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ryo Oda
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshikazu Kubo
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Musculoskeletal Chronobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazuhiro Yagita
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Wang T, Wang Y, Menendez A, Fong C, Babey M, Tahimic CGT, Cheng Z, Li A, Chang W, Bikle DD. Osteoblast-Specific Loss of IGF1R Signaling Results in Impaired Endochondral Bone Formation During Fracture Healing. J Bone Miner Res 2015; 30:1572-84. [PMID: 25801198 PMCID: PMC5690481 DOI: 10.1002/jbmr.2510] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 03/10/2015] [Accepted: 03/13/2015] [Indexed: 12/25/2022]
Abstract
Insulin-like growth factors (IGFs) are important local regulators during fracture healing. Although IGF1 deficiency is known to increase the risk of delayed union or non-union fractures in the elderly population, the underlying mechanisms that contribute to this defect remains unclear. In this study, IGF1 signaling during fracture healing was investigated in an osteoblast-specific IGF1 receptor (IGF1R) conditional knockout (KO) mouse model. A closed tibial fracture was induced in IGF1R(flox/flox) /2.3-kb α1(1)-collagen-Cre (KO) and IGF1R(flox/flox) (control) mice aged 12 weeks. Fracture callus samples and nonfractured tibial diaphysis were collected and analyzed by μCT, histology, immunohistochemistry, histomorphometry, and gene expression analysis at 10, 15, 21, and 28 days after fracture. A smaller size callus, lower bone volume accompanied by a defect in mineralization, bone microarchitectural abnormalities, and a higher cartilage volume were observed in the callus of these KO mice. The levels of osteoblast differentiation markers (osteocalcin, alkaline phosphatase, collagen 1α1) were significantly reduced, but the early osteoblast transcription factor runx2, as well as chondrocyte differentiation markers (collagen 2α1 and collagen 10α1) were significantly increased in the KO callus. Moreover, increased numbers of osteoclasts and impaired angiogenesis were observed during the first 15 days of fracture repair, but decreased numbers of osteoclasts were found in the later stages of fracture repair in the KO mice. Although baseline nonfractured tibias of KO mice had decreased trabecular and cortical bone compared to control mice, subsequent studies with mice expressing the 2.3-kb α1(1)-collagen-Cre ERT2 construct and given tamoxifen at the time of fracture and so starting with comparable bone levels showed similar impairment in fracture repair at least initially. Our data indicate that not only is the IGF1R in osteoblasts involved in osteoblast differentiation during fracture repair, but it plays an important role in coordinating chondrocyte, osteoclast, and endothelial responses that all contribute to the endochondral bone formation required for normal fracture repair.
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Affiliation(s)
- Tao Wang
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
- Department of Orthopedics, Civil Aviation General Hospital, Beijing, China
| | - Yongmei Wang
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Alicia Menendez
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Chak Fong
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Muriel Babey
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Candice GT Tahimic
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Zhiqiang Cheng
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Alfred Li
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Wenhan Chang
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
| | - Daniel D. Bikle
- Endocrine Unit, VA Medical Center and University of California, San Francisco, CA, USA
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13
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Analysis of genetic regulation and cytokine expressions of distraction osteogenesis reconstruction for cleft palate. J Craniofac Surg 2014; 25:2231-6. [PMID: 25023060 DOI: 10.1097/scs.0000000000001029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Because cleft palate (CP) is one of the most common congenital deformities, surgeons have tried for longtime to achieve an ideal reconstruction of the palatal bone defects and restoration of muscle attachments. In this study, a new CP model on rhesus was established and corrected by an approach of distraction osteogenesis (DO), and then quantitative studies of regulation of osteogenesis genes and expression of alkaline phosphatase (ALP), insulin-like growth factor-I (IGF-I), osteopontin (OPN), and osteocalcin (OC) in different phases of new bone formation were preformed. The CP models (23 animals) were established surgically. In the experimental group (21 animals), the tissue defects were repaired by means of DO at the rhythm of 0.4 mm twice per day. The specimens were retrieved in 1, 2, 4, 6, 8, 12, and 24 weeks (3 animals each) after completion of distraction. The IGF-I, ALP, OPN, and OC messenger RNA (mRNA) were detected by real-time reverse transcription polymerase chain reaction, and their proteins were then analyzed by enzyme-linked immunosorbent assay tests. The results are compared with those of the experimental control and empty control groups (2 animals each). In the distraction gap, the mRNA and protein expressions levels of IGF-I and ALP were both highly upregulated and reaching apex in the early phase of new bone formation. Otherwise, the mRNA and protein expressions of OPN and OC demonstrated high level during intermediate and later remodeling stages. These results suggest that the reconstruction of CP bone defect by means of DO could get definitely intramembraneous new bone formation and eventually quite normal bone structure via consecutive remodeling in situ.
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14
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Mozar A, Kondegowda NG, Pollack I, Fenutria R, Vasavada RC. The Role of PTHrP in Pancreatic Beta-Cells and Implications for Diabetes Pathophysiology and Treatment. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9168-3] [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: 10/25/2022]
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15
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Reifenrath J, Angrisani N, Lalk M, Besdo S. Replacement, refinement, and reduction: Necessity of standardization and computational models for long bone fracture repair in animals. J Biomed Mater Res A 2013; 102:2884-900. [DOI: 10.1002/jbm.a.34920] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/30/2013] [Accepted: 07/31/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Janin Reifenrath
- Small Animal Clinic; University of Veterinary Medicine Hannover; Bünteweg 9 30559 Hannover Germany
| | - Nina Angrisani
- Small Animal Clinic; University of Veterinary Medicine Hannover; Bünteweg 9 30559 Hannover Germany
| | - Mareike Lalk
- Small Animal Clinic; University of Veterinary Medicine Hannover; Bünteweg 9 30559 Hannover Germany
| | - Silke Besdo
- Institute of Continuum Mechanics; Leibniz Universität Hannover; Appelstr. 11 30167 Hannover Germany
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16
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Zhang L, Richardson M, Mendis P. Role of chemical and mechanical stimuli in mediating bone fracture healing. Clin Exp Pharmacol Physiol 2012; 39:706-10. [DOI: 10.1111/j.1440-1681.2011.05652.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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17
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Koh A, Niikura T, Lee SY, Oe K, Koga T, Dogaki Y, Kurosaka M. Differential gene expression and immunolocalization of insulin-like growth factors and insulin-like growth factor binding proteins between experimental nonunions and standard healing fractures. J Orthop Res 2011; 29:1820-6. [PMID: 21598309 DOI: 10.1002/jor.21457] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 04/22/2011] [Indexed: 02/04/2023]
Abstract
Insulin-like growth factors (IGF-I/II) are important growth factors in bone, and their actions are regulated by six IGF binding proteins (IGFBPs). However, little is known about their exact functions in fracture healing. The aim of this study was to compare the gene expression and immunolocalization of IGFs and IGFBPs between standard healing fractures and nonunions using rat experimental models. Standard healing fractures and nonunions produced by periosteal cauterization at the fracture site were created in rat femurs. At postfracture days 3, 7, 10, 14, 21, and 28, total RNA was extracted from the callus of the healing fractures and the fibrous tissue of the nonunions, and gene expression were analyzed by real-time PCR. Additionally, immunolocalization of these proteins was studied by immunohistochemistry at postfracture days 7, 14, and 21. In nonunions, the gene expression of IGF-I/II and IGFBP-6 was significantly higher, and that of IGFBP-5 was significantly lower at several time points. The immunolocalization of IGF-I/II and IGFBP-5 was widely distributed in both models. In contrast, that of IGFBP-6 was barely detected in the fracture callus. In conclusion, our results suggest that IGFs/IGFBPs may have important roles not only in fracture healing but also in nonunion formation.
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Affiliation(s)
- Akihiro Koh
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
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18
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Muthusami S, Ramachandran I, Krishnamoorthy S, Govindan R, Narasimhan S. Cissus quadrangularis augments IGF system components in human osteoblast like SaOS-2 cells. Growth Horm IGF Res 2011; 21:343-348. [PMID: 22015109 DOI: 10.1016/j.ghir.2011.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 07/21/2011] [Accepted: 09/14/2011] [Indexed: 11/16/2022]
Abstract
Osteoporosis is a public health problem which is associated with significant morbidity and mortality. Growth factors are produced locally in the bone and control cellular events such as induction of bone growth. Signaling through the Insulin-like growth factor (IGF)-I receptor (IGF-IR) by locally synthesized IGF - I or IGF-II in osteoblast is considered crucial for normal development and for bone remodeling. Traditional use of Cissus quadrangularis (C. quadrangularis) in the treatment of bone disorders have been documented, however its regulatory effects on IGF system components remain largely unknown. The present study is employed to delineate the effects of ethanolic extract of C. quadrangularis on the regulation of IGF system components in human osteoblast like SaOS-2 cells. RT-PCR analysis revealed an increase in the mRNA expression of IGF-I, IGF-II, IGF-IR in cells treated with C. quadrangularis when compared with control cells. The mRNA expression of IGF binding protein-3 (IGFBP-3) did not differ significantly between control and C. quadrangularis treated cells. Immunoradiometric analysis revealed increased levels of IGF-I, IGF-II and IGFBP-3 in the conditioned medium of C. quadrangularis treated cultures when compared with control. Western blotting analysis revealed increase in protein levels of IGF-IR in cells treated with C. quadrangularis. These results indicate positive regulation of C. quadrangularis on the IGF system components of human osteoblast like SaOS-2 cells.
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Affiliation(s)
- Sridhar Muthusami
- Department of Endocrinology, Dr.ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani campus, Chennai, India
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19
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Teriparatide Therapy as an Adjuvant for Tissue Engineering and Integration of Biomaterials. MATERIALS 2011; 4:1117-1131. [PMID: 21857768 PMCID: PMC3156480 DOI: 10.3390/ma4061117] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Critically sized large bone defects commonly result from trauma, radical tumor resections or infections. Currently, massive allografting remain as the clinical standard to treat these critical defects. Unfortunately, allograft healing is limited by the lack of osteogenesis and bio-integration of the graft to the host bone. Based on its widely studied anabolic effects on the bone, we have proposed that teriparatide [recombinant parathyroid hormone (PTH(1-34))] could be an effective adjuvant for massive allograft healing. In support of this theory, here we review studies that have demonstrated that intermittent PTH(1-34) treatment enhances and accelerates the skeletal repair process via a number of mechanisms including: effects on mesenchymal stem cells (MSC), angiogenesis, chondrogenesis, bone formation and remodeling. We also review the current literature on the effects of PTH(1-34) therapy on bone healing, and discuss this drug's long term potential as an adjuvant for endogenous tissue engineering.
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20
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Endogenous tissue engineering: PTH therapy for skeletal repair. Cell Tissue Res 2011; 347:545-52. [PMID: 21626290 DOI: 10.1007/s00441-011-1188-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
Based on its proven anabolic effects on bone in osteoporosis patients, recombinant parathyroid hormone (PTH(1-34)) has been evaluated as a potential therapy for skeletal repair. In animals, the effect of PTH(1-34) has been investigated in various skeletal repair models such as fractures, allografting, spinal arthrodesis and distraction osteogenesis. These studies have demonstrated that intermittent PTH(1-34) treatment enhances and accelerates the skeletal repair process via a number of mechanisms, which include effects on mesenchymal stem cells, angiogenesis, chondrogenesis, bone formation and resorption. Furthermore, PTH(1-34) has been shown to enhance bone repair in challenged animal models of aging, inflammatory arthritis and glucocorticoid-induced bone loss. This pre-clinical success has led to off-label clinical use and a number of case reports documenting PTH(1-34) treatment of delayed-unions and non-unions have been published. Although a recently completed phase 2 clinical trial of PTH(1-34) treatment of patients with radius fracture has failed to achieve its primary outcome, largely because of effective healing in the placebo group, several secondary outcomes are statistically significant, highlighting important issues concerning the appropriate patient population for PTH(1-34) therapy in skeletal repair. Here, we review our current knowledge of the effects of PTH(1-34) therapy for bone healing, enumerate several critical unresolved issues (e.g., appropriate dosing regimen and indications) and discuss the long-term potential of this drug as an adjuvant for endogenous tissue engineering.
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21
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Martin CK, Tannehill-Gregg SH, Wolfe TD, Rosol TJ. Bone-invasive oral squamous cell carcinoma in cats: pathology and expression of parathyroid hormone-related protein. Vet Pathol 2010; 48:302-12. [PMID: 20940448 DOI: 10.1177/0300985810384414] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Feline oral squamous cell carcinoma (OSCC) is the most common oral tumor in cats. There is no effective treatment, and the average duration of survival after diagnosis is only 2 months. Feline OSCC is frequently associated with osteolysis; however, the mechanisms responsible are unknown. The objective of this study was to characterize the epidemiology and pathology of bone-invasive OSCC in cats and to determine the expression of select bone resorption agonists. In sum, 451 cases of feline OSCC were evaluated. There was no sex or breed predisposition, although there were more intact cats in the OSCC group compared to the control group. Gingiva was the most common site, followed by the sublingual region and tongue. Cats with lingual OSCC were younger (mean, 11.9 years) compared to cats with gingival OSCC (mean, 13.6 years). In addition to osteolysis, there was periosteal new bone formation, osseous metaplasia of tumor stroma, and direct apposition of OSCC to fragments of bone, suggestive of bone-binding behavior. Eighty-two cases were selected for immunohistochemical detection of parathyroid hormone-related protein (PTHrP). Specimens with osteolysis had increased PTHrP expression and nuclear localization, compared to OSCC without osteolysis. Thirty-eight biopsies of OSCC with osteolysis were evaluated for tumor necrosis factor α expression, and only 4 biopsies had such expression in a small proportion of tumor cells. Increased tumor expression of PTHrP and increased localization of PTHrP to the nucleus were associated with osteolysis and may play an important role in bone resorption and tumor invasion in cats with OSCC.
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Affiliation(s)
- C K Martin
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, Ohio 43214, USA
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22
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Ellegaard M, Jørgensen NR, Schwarz P. Parathyroid hormone and bone healing. Calcif Tissue Int 2010; 87:1-13. [PMID: 20428858 DOI: 10.1007/s00223-010-9360-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 03/22/2010] [Indexed: 12/13/2022]
Abstract
Fracture healing is a complex process, and a significant number of fractures are complicated by impaired healing and non-union. Impaired healing is prevalent in certain risk groups, such as the elderly, osteoporotics, people with malnutrition, and women after menopause. Currently, no pharmacological treatments are available. There is therefore an unmet need for medications that can stimulate bone healing. Parathyroid hormone (PTH) is the first bone anabolic drug approved for the treatment of osteoporosis, and intriguingly a number of animal studies suggest that PTH could be beneficial in the treatment of fractures and could thus be a potentially new treatment option for induction of fracture healing in humans. Furthermore, fractures in animals with experimental conditions of impaired healing such as aging, estrogen withdrawal, and malnutrition can heal in an expedited manner after PTH treatment. Interestingly, fractures occurring at both cancellous and cortical sites can be treated successfully, indicating that both osteoporotic and nonosteoporotic fractures can be the target of PTH-induced healing. Finally, the data suggest that PTH partly prevents the delay in fracture healing caused by aging. Recently, the first randomized, controlled clinical trial investigating the effect of PTH on fracture healing was published, indicating a possible clinical benefit of PTH treatment in inducing fracture healing. The aim of this article is therefore to review the evidence for the potential of PTH in bone healing, including the underlying mechanisms for this, and to provide recommendations for the clinical testing and use of PTH in the treatment of impaired fracture healing in humans.
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Affiliation(s)
- M Ellegaard
- Research Center of Aging and Osteoporosis, Department of Medicine, Copenhagen University Hospital Glostrup, Nordre Ringvej, 2600, Glostrup, Denmark.
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23
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Abstract
Parathyroid hormone is a well-known regulator of calcium metabolism in the body. It binds to osteoblasts and assists in the regulation of bone turnover. Changes in parathyroid hormone levels have been documented in pathologic states such as osteoporosis, and fluxes are also noted during healing of fractures. Because fracture healing requires time and is sometimes unreliable, a search for fracture-healing adjuvants that accelerate the healing rate and improve reliability of healing is compelling. Parathyroid hormone, as a systemic mediator of calcium and bone metabolism, is a good candidate. Much research has been accomplished in animal models examining the role of parathyroid hormone in fracture healing. Although further research is required, especially in human fracture patients, early indicators are that parathyroid hormone may play a role in accelerating fracture healing in healthy patients and in reducing rates of fracture nonunion in compromised patients or tissue beds.
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24
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Smith SE, Roukis TS. Bone and wound healing augmentation with platelet-rich plasma. Clin Podiatr Med Surg 2009; 26:559-88. [PMID: 19778689 DOI: 10.1016/j.cpm.2009.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Over the past two decades, autologous platelets that have been sequestered, concentrated, and mixed with thrombin to generate growth factor-concentrated platelet-rich plasma for application to bone and wounds to aide healing have been a subject of great interest. This article reviews the literature related to the use of autologous platelet-rich plasma in bone and wound healing, and reviews the processes necessary to secure a high concentration of viable platelets. Although not yet definitive, autologous platelet-rich plasma has been shown to be safe, reproducible, and effective in mimicking the natural process of bone and wound healing.
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Affiliation(s)
- Simon E Smith
- Australasian College of Podiatric Surgeons, Australia.
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25
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Recent advances toward the clinical application of PTH (1-34) in fracture healing. HSS J 2009; 5:149-53. [PMID: 19290582 PMCID: PMC2744747 DOI: 10.1007/s11420-009-9109-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 01/21/2009] [Indexed: 02/07/2023]
Abstract
PTH 1-34, an active form of parathyroid hormone, has been shown to enhance osteoblastic bone formation when administered as a daily subcutaneous injection. The effect of the intermittent administration of PTH (1-34) is an uncoupling of bone turnover with an increase in bone mass and density and decrease in risk of vertebral and nonvertebral fractures. While PTH (1-34) has been used clinically to increase bone mass and reduce fracture risk in postmenopausal women with osteoporosis, there is increasing evidence that PTH (1-34) may promote fracture healing. Animal studies have demonstrated accelerated callus formation with enhanced remodeling and biomechanical properties of the healing fracture. Given these effects, PTH (1-34) will likely be used clinically to enhance fracture union in poor healing situations such as osteoporosis and recalcitrant nonunions.
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26
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Ahmed N, Gan L, Nagy A, Zheng J, Wang C, Kandel RA. Cartilage Tissue Formation Using Redifferentiated Passaged ChondrocytesIn Vitro. Tissue Eng Part A 2009; 15:665-73. [DOI: 10.1089/ten.tea.2008.0004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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27
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Nakasaki M, Yoshioka K, Miyamoto Y, Sasaki T, Yoshikawa H, Itoh K. IGF-I secreted by osteoblasts acts as a potent chemotactic factor for osteoblasts. Bone 2008; 43:869-79. [PMID: 18718566 DOI: 10.1016/j.bone.2008.07.241] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 07/03/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
Abstract
Osteoblast recruitment to the site of future bone formation is essential for skeletal development, bone remodeling and fracture healing. A number of factors associated with bone tissue have been reported to induce directional migration of osteoblasts but the mechanism remains to be clarified. In this study, to explore a major chemotactic factor(s) for osteoblasts, we examined the serum-free medium conditioned by MC3T3-E1 osteoblast-like cells for its ability to induce osteoblast migration. Employing sequential chromatography and tandem mass spectrometry analysis, we purified and identified IGF-I as a potent chemotactic factor from the conditioned medium. IGF-I induced cell migration of both MC3T3-E1 cells and primary mouse osteoblasts, and checkerboard analysis revealed that IGF-I markedly induced directional migration (chemotaxis) of osteoblasts. Neutralization of mouse IGF-I with monoclonal antibodies resulted in delayed osteoblast monolayer wound healing and cellular polarization but addition of human IGF-I reversed these effects. IGF-I also promoted cell spreading on fibronectin in an integrin beta1-dependent manner. IGF-I induced Akt and Rac activation and localized accumulation of phosphatidylinositol 3,4,5-triphosphate (PtdIns (3,4,5)P3) at the membrane in osteoblasts. The phosphatidyl inositol 3 kinase (PI3K) inhibitor LY294002 inhibited IGF-I-induced cell migration and wound healing. Together, the results suggest that IGF-I secreted from osteoblasts in the bone tissue is a potent chemotactic factor that may play a major role in recruitment of osteoblasts during bone formation.
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Affiliation(s)
- Manando Nakasaki
- Department of Biology, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-2 Nakamichi, Higashinari-ku, Osaka 537-8511, Japan.
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28
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Zhang X, Awad HA, O'Keefe RJ, Guldberg RE, Schwarz EM. A perspective: engineering periosteum for structural bone graft healing. Clin Orthop Relat Res 2008; 466:1777-87. [PMID: 18509709 PMCID: PMC2584255 DOI: 10.1007/s11999-008-0312-6] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 05/05/2008] [Indexed: 01/31/2023]
Abstract
Autograft is superior to both allograft and synthetic bone graft in repair of large structural bone defect largely due to the presence of multipotent mesenchymal stem cells in periosteum. Recent studies have provided further evidence that activation, expansion and differentiation of the donor periosteal progenitor cells are essential for the initiation of osteogenesis and angiogenesis of donor bone graft healing. The formation of donor cell-derived periosteal callus enables efficient host-dependent graft repair and remodeling at the later stage of healing. Removal of periosteum from bone autograft markedly impairs healing whereas engraftment of multipotent mesenchymal stem cells on bone allograft improves healing and graft incorporation. These studies provide rationale for fabrication of a biomimetic periosteum substitute that could fit bone of any size and shape for enhanced allograft healing and repair. The success of such an approach will depend on further understanding of the molecular signals that control inflammation, cellular recruitment as well as mesenchymal stem cell differentiation and expansion during the early phase of the repair process. It will also depend on multidisciplinary collaborations between biologists, material scientists and bioengineers to address issues of material selection and modification, biological and biomechanical parameters for functional evaluation of bone allograft healing.
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Affiliation(s)
- Xinping Zhang
- The Center for Musculoskeletal Research, University of Rochester Medical Center, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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29
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Gardner MJ, van der Meulen MCH, Carson J, Zelken J, Ricciardi BF, Wright TM, Lane JM, Bostrom MP. Role of parathyroid hormone in the mechanosensitivity of fracture healing. J Orthop Res 2007; 25:1474-80. [PMID: 17568439 PMCID: PMC2948234 DOI: 10.1002/jor.20427] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The mechanical environment at a fracture site can influence the course of healing. Intermittent parathyroid hormone (PTH) has been shown to accelerate fracture healing. Intact bone models show that mechanical loading and PTH have a synergistic beneficial effect on osteogenesis. We hypothesized that PTH and mechanical loading would have a similar synergistic effect on fracture healing. Eighty mice underwent surgical osteotomy and intramedullary nailing of the tibia. The mice were divided into four groups: one underwent daily loading, one received daily subcutaneous PTH injections (30 microg/kg/day), one received both loading and PTH, and a control group received sham loading and vehicle injection. Daily loading was applied to the ends of the tibia with an external loading device for 2 weeks. Fracture healing was assessed by microcomputed tomography, histology, and biomechanical testing. The group with both loading and PTH had increased osteoblast and osteoclast activity and was the only group with a significantly larger callus mineral density and bone volume fraction. The PTH only group had significantly more osteoid in the callus compared to the control group, indicating enhanced early osteoblast activity. This group also had a significantly higher bone mineral content and total bone volume compared to controls. The group that received loading as the only intervention had significantly greater osteoclast activity versus controls. The contribution of loading and PTH administration to the fracture healing cascade indicates a synergistic effect. This finding may be of potential clinical utility when weight bearing is utilized to stimulate lower extremity fracture healing.
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Affiliation(s)
- Michael J Gardner
- Hospital for Special Surgery, 535 East 70th Street, New York, New York 10021, USA.
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30
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HUGHES MICHAELS, KAZMIER PETER, BURD TIMOTHYA, ANGLEN JEFF, STOKER AARONM, KUROKI KEIICHI, CARSON WILLIAML, COOK JAMESL. ENHANCED FRACTURE AND SOFT-TISSUE HEALING BY MEANS OF ANABOLIC DIETARY SUPPLEMENTATION. J Bone Joint Surg Am 2006. [DOI: 10.2106/00004623-200611000-00010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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31
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Bevelander GS, Hang X, Abbink W, Spanings T, Canario AVM, Flik G. PTHrP potentiating estradiol-induced vitellogenesis in sea bream (Sparus auratus, L.). Gen Comp Endocrinol 2006; 149:159-65. [PMID: 16839552 DOI: 10.1016/j.ygcen.2006.05.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Revised: 05/03/2006] [Accepted: 05/24/2006] [Indexed: 11/22/2022]
Abstract
In fish, vitellogenin is an important nutritional precursor protein produced solely in the liver and released into the blood where it binds calcium. In the gilthead sea bream (Sparus auratus) 17beta-Estradiol (E2) plays an important role in the synthesis of vitellogenin, but also the pituitary hormones prolactin (PRL) and growth hormone (GH) can stimulate vitellogenin induction in fish. Considering the emerging involvement of PTHrP in fish calcium metabolism and the importance of calcium regulation in reproduction, we investigated the possible role of PTHrP in vitellogenesis. E2-naïve and E2-primed sea bream hepatocytes were used in an in vitro primary hepatocyte culture and stimulated with a recombinant sea bream PTHrP (sbPTHrP) to establish the contribution of sbPTHrP alone or in combination with E2 to the regulation of hepatic vitellogenin synthesis. Hepatocytes stimulated solely with sbPTHrP were not affected in their vitellogenesis. However, in hepatocytes stimulated with E2 in combination with sbPTHrP a higher vitellogenin production was seen than with E2 alone. It is concluded that sbPTHrP has a potentiating effect on estradiol stimulation of vitellogenin production by sea bream hepatocytes. The sea bream provides a unique model where vitellogenesis regulation can be studied on E2-naïve liver cells, both in vivo and in vitro.
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Affiliation(s)
- Gideon S Bevelander
- Department of Animal Physiology, Faculty of Science, Radboud University Nijmegen, Toernooiveld 1, ED Nijmegen, The Netherlands
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32
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Hughes MS, Kazmier P, Burd TA, Anglen J, Stoker AM, Kuroki K, Carson WL, Cook JL. Enhanced fracture and soft-tissue healing by means of anabolic dietary supplementation. J Bone Joint Surg Am 2006; 88:2386-94. [PMID: 17079395 DOI: 10.2106/jbjs.f.00507] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Malnutrition is common in hospitalized injured patients. It contributes to delayed fracture-healing and increased morbidity. However, relatively little attention has been directed toward nutritional strategies for augmenting musculoskeletal recovery after a fracture. This animal study was designed to examine the effects of dietary protein intake and the role of conditionally essential amino acids in muscle and bone-healing after a fracture. METHODS One hundred adult male rats were used. Ten rats served as controls and received a 15% protein diet throughout the study. The remaining ninety rats received a 6% protein diet for five weeks to induce protein malnutrition. The rats underwent intramedullary nailing and closed midshaft fracture of one femur. After the fracture, they were separated into three isocaloric dietary groups. Group P6 received a diet with 6% protein; Group P15, a diet with 15% protein; and group P30, a diet with 30% protein with conditionally essential amino acids. At two, four, and six weeks after surgery, ten animals from each group were killed and the femora were evaluated with dual x-ray absorptiometry, histomorphometric assessment of callus, and torsional testing. The quadriceps muscles were analyzed for total mass, total protein content, and for mRNA expression of insulin-like growth factor-1 (IGF-1), IGF-2, IGF receptors, actin, myosin, and vascular endothelial growth factor (VEGF). RESULTS The P30 group demonstrated elevations in albumin, body mass, muscle mass, total protein content of muscle, and bone mineral density in the fracture callus compared with the P6 diet group at six weeks (p < 0.05). Molecular analysis of muscle revealed that IGF-1, IGF-2, IGF receptors, myosin, actin, and VEGF gene expression were significantly (p < 0.001) higher in the P6 group compared with the P30 group. Biomechanical testing of the femora, however, showed no significant differences. CONCLUSIONS Dietary supplementation with conditionally essential amino acids in malnourished animals had anabolic effects on bone mineralization, body mass, and muscle mass.
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Affiliation(s)
- Michael S Hughes
- Department of Orthopaedics, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65212, USA
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Simpson AHRW, Mills L, Noble B. The role of growth factors and related agents in accelerating fracture healing. ACTA ACUST UNITED AC 2006; 88:701-5. [PMID: 16720758 DOI: 10.1302/0301-620x.88b6.17524] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- A H R W Simpson
- The Musculoskeletal Tissue Engineering Consortium, Room SU304, University of Edinburgh, Chancellors Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
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Koch H, Jadlowiec JA, Campbell PG. Insulin-like Growth Factor-I Induces Early Osteoblast Gene Expression in Human Mesenchymal Stem Cells. Stem Cells Dev 2005; 14:621-31. [PMID: 16433617 DOI: 10.1089/scd.2005.14.621] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human adult mesenchymal stem cells (hMSCs) differentiate into an osteogenic lineage if the appropriate differentiative cues, such as dexamethasone or bone morphogenetic protein 2 (BMP-2), are present. This study was undertaken to determine the role of insulin-like growth factor I (IGFI) in the regulation of early osteoblast differentiation in hMSC. Previous studies have shown that IGF-I, regulates bone formation and remodeling by participating in the differentiation of mature cells of osteoblast lineage. We hypothesized that IGF-I exerted its effects early, but the effects were too subtle to be detected. Therefore, engineered hMSCs to produce IGF-I via adenoviral transfection and used quantitative real-time PCR (qPCR) to assess marker gene expression. Here we show that IGF-I up-regulates Type I collagen, Runx2, and alkaline phosphatase (Alp) gene expression in hMSCs, genes indicative of early osteogenic differentiation. We also observed mineral deposition in the absence of dexamethasone (Dex) in hMSC cultures treated with recombinant human BMP-2 after transduction with Ad-IGF-I. In conclusion Igf-I transduction up-regulated markers of osteoblastic differentiation and in conjunction with recombinant BMP-2-induced matrix mineralization independently of Dex (see Salasznyk et al., Stem Cells Dev 14(6):608-620, 2005, this issue).
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Affiliation(s)
- Hannjörg Koch
- Department of Orthopaedic Surgery, University of Greifswald, Greifswald, Germany
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Abstract
Platelet-rich plasma (PRP), derived from autologous blood, is defined as a volume of plasma that has a platelet concentration that typically is five times greater (approximately 1,000,000/microl) than physiologic levels. PRP serves as a reservoir of critical growth factors, including platelet-derived growth factor, transforming growth factor-beta, and insulin-like growth factor-I. Although there is an abundance of literature pertaining to dental applications, this article highlights the use of PRP in orthopedic applications, ranging from PRP preparation to in vitro and in vivo studies to clinical research.
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Affiliation(s)
- Ankur Gandhi
- Department of Orthopaedics, University of Medicine & Dentistry-New Jersey Medical School, 185 South Orange Avenue, MSB G-574, Newark, NJ 07103, USA.
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Nakazawa T, Nakajima A, Shiomi K, Moriya H, Einhorn TA, Yamazaki M. Effects of low-dose, intermittent treatment with recombinant human parathyroid hormone (1-34) on chondrogenesis in a model of experimental fracture healing. Bone 2005; 37:711-9. [PMID: 16143574 DOI: 10.1016/j.bone.2005.06.013] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2005] [Revised: 05/30/2005] [Accepted: 06/03/2005] [Indexed: 11/19/2022]
Abstract
Recent studies have demonstrated that intermittent administration of parathyroid hormone (PTH) enhances osteogenesis (hard callus formation) and increases mechanical strength in experimental fracture healing. Thus far, however, effects of PTH on chondrogenesis (soft callus formation) during fracture healing have not been fully elucidated. In the present study, we analyzed the underlying molecular mechanism by which exogenous PTH would affect chondrogenesis in a model of experimental fracture healing. Unilateral femoral fractures were produced in 2-month-old Sprague-Dawley rats. Daily subcutaneous injections of 10 microg/kg of recombinant human PTH(1-34) [rhPTH(1-34)] were administered over a 28-day period of fracture healing. Control animals were injected with vehicle solution (normal saline) alone. The results showed that, on day 14 after fracture, cartilage area in the PTH-treated group was significantly increased (1.4-fold) compared with the controls, but this increase was not observed at days 21 and 28. In the early stage of chondrogenesis (days 4-7), cell proliferation, expressed as the rate of proliferating cell nuclear antigen-positive cells, was increased in mesenchymal (chondroprogenitor) cells but not chondrocytes in the PTH-treated group compared with controls. In addition, gene expression of SOX-9 was up-regulated in the PTH-treated group on day 4 (1.4-fold), and this was accompanied by enhanced expression of pro-alpha1 (II) collagen (1.8-fold). After 14 days, there were no significant differences between groups in either cell proliferation or the expression levels of cartilage differentiation-related genes (SOX-9, pro-alpha1 (II) collagen, pro-alpha1 (X) collagen and osteopontin). These results suggest that intermittent treatment with low-dose rhPTH(1-34) induces a larger cartilaginous callus but does not delay chondrocyte differentiation during fracture healing.
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Affiliation(s)
- Tetsuro Nakazawa
- Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8677, Japan
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Kato A, Suzuki M, Karasawa Y, Sugimoto T, Doi K. PTHrP and PTH/PTHrP receptor 1 expression in odontogenic cells of normal and HHM model rat incisors. Toxicol Pathol 2005; 33:456-64. [PMID: 16036863 DOI: 10.1080/01926230590959604] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Parathyroid hormone related peptide (PTHrP) was discovered as a causative factor of humoral hypercalcemia of malignancy (HHM). We examined PTHrP and its receptor (PTHR1) expression patterns in odontogenic cells in normal and HHM model rat incisors. Nontreated nude rats serving as the normal control and HHM model rats produced by implantation of PTHrP-expressing tumor (LC-6) cells were prepared. HHM rats fractured its incisor, and histopathologically, restrict population of odontoblasts showed findings classified as "shortening of high columnar odontoblasts" and "dentin niche." The incisors were immunostained against PTHrP and PTHR1. In normal rats, PTHrP and PTHR1 colocalized in ameloblasts, cementoblasts, and odontoblastic cells from mesenchymal cells to columnar odontoblasts. In high columnar odontoblasts, PTHrP solely expressed. In the HHM animals, although the expression patterns were identical to those of the normal rats in normal area, the shortened high columnar odontoblasts maintained PTHR1 expression and dentin niche comprising odontoblastic cells expressed both proteins. In the HHM model, the protein expression patterns changed in the odontoblastic cells with histological anomalies, and thus direct relations between the anomalies and PTHrP/PTHR1 axis are suggested.
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Affiliation(s)
- Atsuhiko Kato
- Safety Assessment Department, Chugai Pharmaceutical Co. Ltd., 1-135 Komakado, Gotemba-shi, Shizuoka 412-8513, Japan.
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Price J, Allen S. Exploring the mechanisms regulating regeneration of deer antlers. Philos Trans R Soc Lond B Biol Sci 2004; 359:809-22. [PMID: 15293809 PMCID: PMC1693364 DOI: 10.1098/rstb.2004.1471] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Deer antlers are the only mammalian appendages capable of repeated rounds of regeneration; every year they are shed and regrow from a blastema into large branched structures of cartilage and bone that are used for fighting and display. Longitudinal growth is by a process of modified endochondral ossification and in some species this can exceed 2 cm per day, representing the fastest rate of organ growth in the animal kingdom. However, despite their value as a unique model of mammalian regeneration the underlying mechanisms remain poorly understood. We review what is currently known about the local and systemic regulation of antler regeneration and some of the many unsolved questions of antler physiology are discussed. Molecules that we have identified as having potentially important local roles in antlers include parathyroid hormone-related peptide and retinoic acid (RA). Both are present in the blastema and in the rapidly growing antler where they regulate the differentiation of chondrocytes, osteoblasts and osteoclasts in vitro. Recent studies have shown that blockade of RA signalling can alter cellular differentiation in the blastema in vivo. The trigger that regulates the expression of these local signals is likely to be changing levels of sex steroids because the process of antler regeneration is linked to the reproductive cycle. The natural assumption has been that the most important hormone is testosterone, however, at a cellular level oestrogen may be a more significant regulator. Our data suggest that exogenous oestrogen acts as a 'brake', inhibiting the proliferation of progenitor cells in the antler tip while stimulating their differentiation, thus inhibiting continued growth. Deciphering the mechanism(s) by which sex steroids regulate cell-cycle progression and cellular differentiation in antlers may help to address why regeneration is limited in other mammalian tissues.
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Affiliation(s)
- J Price
- Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
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Dooley PC, Howgate ML, Schuijers JA, Grills BL. Early callus of fractured rib of rat contracts and relaxes ex vivo. J Orthop Res 2004; 22:1063-71. [PMID: 15304280 DOI: 10.1016/j.orthres.2003.12.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/31/2003] [Indexed: 02/04/2023]
Abstract
PURPOSE Wound contraction is an essential process in early soft-tissue repair, yet contraction of callus in fracture repair has not been investigated previously. Fracture callus consists of several cell types, many of which may have the capacity to contract. Accordingly, the purpose of the present study was to (i) determine whether early soft fracture calluses contract and relax ex vivo and (ii) identify and locate the contractile protein, alpha smooth muscle actin (alphaSMA) in callus. METHODS One non-weight-bearing rib was fractured in adult male rats under anaesthesia and 10 calluses were removed 5, 7 and 9 days later for examination. Force production by calluses was measured using a sensitive force transducer when callus preparations were immersed sequentially in solutions known to either contract or relax smooth muscle preparations. Calluses and unfractured rib were analysed for the presence of alphaSMA using Western Blot and immunohistochemical techniques. RESULTS When immersed in normal Krebs-Henseleit solution (K-H; pH 7.4, 22 degrees C) 7 callus preparations contracted and 3 relaxed. The force response was phasic (3 calluses) or tonic (7 calluses). Subsequent immersion in Ca(2+)-free K-H resulted in no change in force in 4 calluses, a decrease in force (relaxation) in 3 calluses, and an increase in force (contraction) in 2 calluses when compared to the force in the preceding solution (K-H). The final incubation in a solution having a high [K+] (64 mM) partially relaxed 6 calluses, contracted 3 and produced no change in force in 1 callus compared to the final force of the callus in the Ca(2+)-free solution. Collagen (in the form of rat Achilles tendon), the major structural protein in soft fracture callus, relaxed in K-H and continued to relax during exposure to Ca(2+)-free K-H and to solutions having a high [K+]. Western Blot and immunohistochemical studies detected the presence of alphaSMA in calluses and (in particular) in osteoprogenitor cells of fibrous callus respectively, as well as its absence from unfractured rib. CONCLUSIONS (i) Early, soft fracture callus is capable of contracting and relaxing, (ii) the responses of callus to K-H, Ca(2+)-free and high [K+] solutions are distinctly different from the responses of smooth muscle preparations reported in the literature, (iii) the cell types in callus, particularly osteoprogenitor cells in uncalcified, collagenous matrix, have an essential contractile protein, alphaSMA, to support the observed contraction and relaxation and (iv) the contraction of soft fracture callus may facilitate fracture repair by creating tension within the callus and drawing the fracture ends together.
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Affiliation(s)
- Philip C Dooley
- Department of Human Physiology and Anatomy, School of Human Biosciences, La Trobe University, Victoria 3086, Australia
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Lane JM, Gardner MJ, Lin JT, van der Meulen MC, Myers E. The aging spine: new technologies and therapeutics for the osteoporotic spine. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2003; 12 Suppl 2:S147-54. [PMID: 14534849 PMCID: PMC3591818 DOI: 10.1007/s00586-003-0636-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Accepted: 09/17/2003] [Indexed: 10/26/2022]
Abstract
Osteoporosis results in low-energy fractures of the spine. The load necessary to cause a vertebral fracture is determined by the characteristics related to the vertebral body structure, mineral content, and quality of bone. Radiographic techniques centered on dual X-ray absorptiometry (DXA) permit a determination of bone mass and fracture risk. Current medical therapies principally using bisphosphonate and pulsatile PTH profoundly decrease the risk of fracture (50+%). Fall prevention strategies can further decrease the possibility of fracture. A comprehensive approach to osteoporosis can favorably alter the disease.
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Affiliation(s)
- Joseph M Lane
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, New York, USA.
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