51
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Strobel C, Bormann N, Kadow-Romacker A, Schmidmaier G, Wildemann B. Sequential release kinetics of two (gentamicin and BMP-2) or three (gentamicin, IGF-I and BMP-2) substances from a one-component polymeric coating on implants. J Control Release 2011; 156:37-45. [DOI: 10.1016/j.jconrel.2011.07.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/22/2011] [Accepted: 07/03/2011] [Indexed: 01/22/2023]
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52
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53
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Culture media for the differentiation of mesenchymal stromal cells. Acta Biomater 2011; 7:463-77. [PMID: 20688199 DOI: 10.1016/j.actbio.2010.07.037] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/20/2010] [Accepted: 07/27/2010] [Indexed: 02/08/2023]
Abstract
Mesenchymal stromal cells (MSCs) can be isolated from various tissues such as bone marrow aspirates, fat or umbilical cord blood. These cells have the ability to proliferate in vitro and differentiate into a series of mesoderm-type lineages, including osteoblasts, chondrocytes, adipocytes, myocytes and vascular cells. Due to this ability, MSCs provide an appealing source of progenitor cells which may be used in the field of tissue regeneration for both research and clinical purposes. The key factors for successful MSC proliferation and differentiation in vitro are the culture conditions. Hence, we here summarize the culture media and their compositions currently available for the differentiation of MSCs towards osteogenic, chondrogenic, adipogenic, endothelial and vascular smooth muscle phenotypes. However, optimal combination of growth factors, cytokines and serum supplements and their concentration within the media is essential for the in vitro culture and differentiation of MSCs and thereby for their application in advanced tissue engineering.
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54
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Jimenez-Andrade JM, Mantyh WG, Bloom AP, Freeman KT, Ghilardi JR, Kuskowski MA, Mantyh PW. The effect of aging on the density of the sensory nerve fiber innervation of bone and acute skeletal pain. Neurobiol Aging 2010; 33:921-32. [PMID: 20947214 DOI: 10.1016/j.neurobiolaging.2010.08.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 08/10/2010] [Accepted: 08/18/2010] [Indexed: 02/05/2023]
Abstract
As humans age there is a decline in most sensory systems including vision, hearing, taste, smell, and tactile acuity. In contrast, the frequency and severity of musculoskeletal pain generally increases with age. To determine whether the density of sensory nerve fibers that transduce skeletal pain changes with age, calcitonin gene related peptide (CGRP) and neurofilament 200 kDa (NF200) sensory nerve fibers that innervate the femur were examined in the femurs of young (4-month-old), middle-aged (13-month-old) and old (36-month-old) male F344/BNF1 rats. Whereas the bone quality showed a significant age-related decline, the density of CGRP(+) and NF200(+) nerve fibers that innervate the bone remained remarkably unchanged as did the severity of acute skeletal fracture pain. Thus, while bone mass, quality, and strength undergo a significant decline with age, the density of sensory nerve fibers that transduce noxious stimuli remain largely intact. These data may in part explain why musculoskeletal pain increases with age.
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Affiliation(s)
- Juan M Jimenez-Andrade
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
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55
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Abstract
Osteoblasts are integral to the development, growth, function, repair and maintenance of bone. The osteoblast forms organic, non-mineralized bone matrix and is involved in complex interactions with a variety of factors, mediators and cell types. Degeneration, pathology, and trauma cause disruption and destruction of the normal skeletal environment and may lead to bone loss. There is a rise in active populations involved in trauma, elderly patients with fragility fractures and an overall increase in primary, revision and reconstructive bone and joint surgery. Despite the rapid evolution of implant technologies and bone grafting techniques, there is still a great demand for novel bone replacement strategies. Bone tissue engineering is the state of the art science with the potential to regenerate bone with natural form and function. This review presents the biology of osteoblasts and their current applications in bone tissue engineering biotechnologies and role in stem cell, bioactive factor, recombinant signalling molecule and gene therapy research.
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Affiliation(s)
- P Jayakumar
- Department of Biomaterials, Kings College London, UK
| | - L Di Silvio
- Department of Biomaterials, Kings College London, UK
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56
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Barton ER, Crowder C. Growth Factor Targets for Orthodontic Treatments. Semin Orthod 2010. [DOI: 10.1053/j.sodo.2010.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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57
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Liu Y, Wu G, de Groot K. Biomimetic coatings for bone tissue engineering of critical-sized defects. J R Soc Interface 2010; 7 Suppl 5:S631-47. [PMID: 20484228 DOI: 10.1098/rsif.2010.0115.focus] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The repair of critical-sized bone defects is still challenging in the fields of implantology, maxillofacial surgery and orthopaedics. Current therapies such as autografts and allografts are associated with various limitations. Cytokine-based bone tissue engineering has been attracting increasing attention. Bone-inducing agents have been locally injected to stimulate the native bone-formation activity, but without much success. The reason is that these drugs must be delivered slowly and at a low concentration to be effective. This then mimics the natural method of cytokine release. For this purpose, a suitable vehicle was developed, the so-called biomimetic coating, which can be deposited on metal implants as well as on biomaterials. Materials that are currently used to fill bony defects cannot by themselves trigger bone formation. Therefore, biological functionalization of such materials by the biomimetic method resulted in a novel biomimetic coating onto different biomaterials. Bone morphogenetic protein 2 (BMP-2)-incorporated biomimetic coating can be a solution for a large bone defect repair in the fields of dental implantology, maxillofacial surgery and orthopaedics. Here, we review the performance of the biomimetic coating both in vitro and in vivo.
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Affiliation(s)
- Yuelian Liu
- Department of Oral Implantology and Prosthodontics, Academic Centre of Dentistry Amsterdam (ACTA), VU University and University of Amsterdam, Amsterdam, The Netherlands.
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58
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Porter JR, Ruckh TT, Popat KC. Bone tissue engineering: a review in bone biomimetics and drug delivery strategies. Biotechnol Prog 2010; 25:1539-60. [PMID: 19824042 DOI: 10.1002/btpr.246] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Critical-sized defects in bone, whether induced by primary tumor resection, trauma, or selective surgery have in many cases presented insurmountable challenges to the current gold standard treatment for bone repair. The primary purpose of a tissue-engineered scaffold is to use engineering principles to incite and promote the natural healing process of bone which does not occur in critical-sized defects. A synthetic bone scaffold must be biocompatible, biodegradable to allow native tissue integration, and mimic the multidimensional hierarchical structure of native bone. In addition to being physically and chemically biomimetic, an ideal scaffold is capable of eluting bioactive molecules (e.g., BMPs, TGF-betas, etc., to accelerate extracellular matrix production and tissue integration) or drugs (e.g., antibiotics, cisplatin, etc., to prevent undesired biological response such as sepsis or cancer recurrence) in a temporally and spatially controlled manner. Various biomaterials including ceramics, metals, polymers, and composites have been investigated for their potential as bone scaffold materials. However, due to their tunable physiochemical properties, biocompatibility, and controllable biodegradability, polymers have emerged as the principal material in bone tissue engineering. This article briefly reviews the physiological and anatomical characteristics of native bone, describes key technologies in mimicking the physical and chemical environment of bone using synthetic materials, and provides an overview of local drug delivery as it pertains to bone tissue engineering is included.
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Affiliation(s)
- Joshua R Porter
- Department of Mechanical Engineering, School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
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59
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Abstract
Alteration of the bone healing process with bone morphogenetic proteins offers a new perspective in orthopaedic surgery in those adverse situations that necessitate bone grafting. BMPs have been demonstrated to be effective and safe for human application and have an efficacy comparable with that of autologous bone grafting. Nevertheless, clinical trials with level 1 evidence are still limited in their ability to extrapolate robust and safe clinical conclusions for the possible indications mentioned in this article. Future research should refine issues regarding the relative effectiveness of bone morphogenetic proteins, the interaction between bone morphogenetic protein subtypes, and their specific effect on various target cell populations.
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60
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No effect of autologous growth factors (AGF) around ungrafted loaded implants in dogs. INTERNATIONAL ORTHOPAEDICS 2009; 34:925-30. [PMID: 19856178 DOI: 10.1007/s00264-009-0897-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 10/08/2009] [Accepted: 10/09/2009] [Indexed: 10/20/2022]
Abstract
Autologous growth factors (AGF) is a growth-factor-rich concentrate of platelets, white blood cells and fibrinogen. Application of AGF was presumed to improve implant fixation and gap healing of non-grafted, loaded implants. We inserted one loaded titanium implant intra-articularly in each medial femoral condyle of eight dogs. Each implant was surrounded by a 0.75 mm gap. One implant in each dog was coated with AGF prior to implantation whereas the contralateral implant served as a control. AGF was prepared by isolating the buffy-coat from blood and further concentrated using an Interpore Cross UltraConcentrator. Platelet counts were increased from a median baseline of 168x10(3)/microl to 1003x10(3)/microl in AGF. However, AGF had no significant effect on implant fixation or bone formation. Even though AGF increased ultimate shear strength and energy absorption by approximately 50%, these differences had a p-value less than 0.05. The sample size in this study was small and any negative conclusions should be taken with caution due to low statistical power. We have previously demonstrated that AGF significantly improves fixation and incorporation of grafted implants. AGF might require mixing with an osteoconductive grafting material in order to provide a scaffold on which to foster bone growth and to keep the growth factors on location for a prolonged period.
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61
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Megas P, Syggelos SA, Kontakis G, Giannakopoulos A, Skouteris G, Lambiris E, Panagiotopoulos E. Intramedullary nailing for the treatment of aseptic femoral shaft non-unions after plating failure: effectiveness and timing. Injury 2009; 40:732-7. [PMID: 19371870 DOI: 10.1016/j.injury.2008.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Accepted: 11/11/2008] [Indexed: 02/02/2023]
Abstract
This retrospective, multicentre study aimed to evaluate reamed intramedullary nailing (IMN) for the treatment of 30 cases of aseptic femoral shaft non-union after plating failure. Following nailing, 29 non-unions had healed by a mean 7.93 months. In one case a hypertrophic non-union required renailing after 8 months, using a nail of greater diameter, and united within five further months. Healing times were not related to whether the fracture was open or closed, the type non-union or the type of fracture. The delay from the initial plating to intramedullary nailing had a statistically significant effect on healing time and final outcome. This treatment is cost effective and should be implemented as soon as the non-union is diagnosed.
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62
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Marzona L, Pavolini B. Play and players in bone fracture healing match. CLINICAL CASES IN MINERAL AND BONE METABOLISM : THE OFFICIAL JOURNAL OF THE ITALIAN SOCIETY OF OSTEOPOROSIS, MINERAL METABOLISM, AND SKELETAL DISEASES 2009; 6:159-162. [PMID: 22461167 PMCID: PMC2781220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bone fractured healing is a specialized wound-healing response that leads to regeneration without scar restoring its own ability of mechanical loading. The four stage classification of fracture healing process, by John Hunter, is still the frame in which the new biological and molecular findings settle in.Nowadays the fracture healing is pictured like a playground where growth and differentiation factors, hormones, cytokines, and extracellular matrix play with bone and cartilage forming primary cells and muscle mesenchymal cells in a well orchestrated series of biological events. The ongoing knowledge of cellular and molecular interactions between blood vessels and bone cells shows great promise to enhance fracture management and the unsuccessfull process of bone healing.
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Affiliation(s)
- Lorenzo Marzona
- U.O. di Ortopedia e Traumatologia AUSL1 Massa e Carrara Regione Toscana - Italy
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63
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Clavicular Nonunion Associated With Thoracic Outlet Syndrome Treated With Knowles Pin Fixation, Autogenous Bone Marrow Graft, and Autologous Fibrin Clots. ACTA ACUST UNITED AC 2009; 66:E20-3. [DOI: 10.1097/01.ta.0000222581.18156.9c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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64
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Yu X, Qu H, Knecht DA, Wei M. Incorporation of bovine serum albumin into biomimetic coatings on titanium with high loading efficacy and its release behavior. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:287-294. [PMID: 18763021 DOI: 10.1007/s10856-008-3571-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 08/18/2008] [Indexed: 05/26/2023]
Abstract
Bovine serum albumin (BSA) was employed as a model protein to study its loading efficiency into a calcium phosphate (CaP) coating on titanium substrates. It is found that the protein loading efficiency can be adjusted by varying the specific configurations of the coating system such as simulated body fluid (SBF) volume, solution height and container selection for the SBF. A BSA loading efficiency as high as 90% was achieved when the ratio of the substrate surface area to modified SBF (m-SBF) volume was as high as 0.072. The release of BSA from the biomimetic coatings was also investigated in vitro. A sustained release was achieved although a large quantity of BSA was still trapped in the coating after 15 days of immersion in a phosphate buffer solution. A much faster release rate would be expected when the coating is implanted in vivo due to the active involvement of osteoclast cells and enzymes.
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Affiliation(s)
- Xiaohua Yu
- Department of Chemical, University of Connecticut, U-3136, Storrs, CT 06269, USA
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65
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D'Elia CO, de Rezende MU, Bitar AC, Tatsui N, Pécora JR, Camanho GL. THE USE OF PLATELET RICH PLASMA WITH BONE MARROW ASPIRATE IN PUDDU TIBIAL OSTEOTOMY. Rev Bras Ortop 2009; 44:508-12. [PMID: 27077061 PMCID: PMC4816828 DOI: 10.1016/s2255-4971(15)30149-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Objective: The present study was performed in order to evaluate the use of platelet rich plasma associated to bone marrow aspirate, substituting autologous iliac bone graft in medial opening wedge osteotomy (OWHTO). Methods: Twenty-five patients were submitted to tibial opening wedge osteotomy, being divided into two groups. Iliac group: 14 patients submitted to OWHTO, using autologous iliac bone graft to fill the gap. PRP group: 11 patients using platelet rich plasma associated to bone marrow aspirate to fill the gap. We evaluated bleeding (hemoglobin and hematocrit levels) and pain (visual analogic scale-VAS), then we compared the groups regarding these variables. Results: Differences between the groups were not found regarding hemoglobin levels (p=0.820) and hematocrit levels (p=0.323). The groups were not different regarding pain measured with VAS (p=0.538). Conclusion: The use of platelet rich plasma associated to bone marrow aspirate in medial opening wedge osteotomy did not offer advantages over autologous iliac bone graft regarding bleeding and pain.
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Affiliation(s)
- Caio Oliveira D'Elia
- Post-graduate Student, Department of Orthopedics and Traumatology, School of Medicine, USP
| | | | | | - Nelson Tatsui
- Assistant Physician, Department of Hematology, HC/FMUSP
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66
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Olkku A, Mahonen A. Wnt and steroid pathways control glutamate signalling by regulating glutamine synthetase activity in osteoblastic cells. Bone 2008; 43:483-93. [PMID: 18555765 DOI: 10.1016/j.bone.2008.04.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 03/06/2008] [Accepted: 04/20/2008] [Indexed: 10/22/2022]
Abstract
Glutamate signalling has recently been found functional also outside the central nervous system, especially in bone. Glutamate is converted to glutamine by glutamine synthetase (GS), which is therefore able to regulate intracellular concentrations of glutamate. We previously characterized the induction of GS expression by glucocorticoids (GCs) in human osteoblast-like cells. Besides this observation, the mechanisms controlling GS in bone are unknown. Therefore, the aim of our present study was to investigate further the regulation of GS in osteoblastic cells. We observed that vitamin D inhibited basal and, even more efficiently, GC-stimulated GS activity by affecting both the mRNA and protein levels of the enzyme in human MG-63 osteoblast-like cells. In osteoblasts derived from rat bone marrow stem cells (rMSCs), GS activity was induced accordingly by the osteogenic culture conditions including GCs. Also in these primary cells, vitamin D clearly inhibited GS activity. In addition, the canonical Wnt signalling pathway was characterized as a negative regulator of GS activity. All these changes in GS activity were reflected on the intracellular glutamate concentration. Our results provide novel evidence that GS activity and expression are regulated by several different signalling pathways in osteoblastic cells. Therefore, GS is a strategic enzyme in controlling glutamate concentration in bone environment: GCs decreased the amount of this signalling molecule while vitamin D and Wnt signalling pathway increased it. Interestingly, GS activity and expression declined rapidly when the rMSC derived osteoblasts began to mineralize. Due to its downregulation during osteoblast mineralization, GS could be held as a marker for osteoblast development. Further supporting this, GS activity was stimulated and intracellular glutamate concentration maintained by the N-methyl-d-aspartate (NMDA) type glutamate receptor antagonist MK801, which inhibited osteogenic differentiation of the rMSCs. GS, a novel target for both steroidal and Wnt pathways in bone, might be a central player in the regulation of osteoblastogenesis and/or intercellular signal transmission. Therefore, the proper understanding of the interplay of these three signalling cascades, i.e., steroidal, Wnt, and glutamate signalling, gives vital information on how bone cells communicate together aiming to keep bone healthy.
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Affiliation(s)
- Anu Olkku
- Institute of Biomedicine, Medical Biochemistry, University of Kuopio, Kuopio, Finland
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67
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Hallman M, Thor A. Bone substitutes and growth factors as an alternative/complement to autogenous bone for grafting in implant dentistry. Periodontol 2000 2008; 47:172-92. [PMID: 18412581 DOI: 10.1111/j.1600-0757.2008.00251.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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68
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de Jonge LT, Leeuwenburgh SCG, Wolke JGC, Jansen JA. Organic–Inorganic Surface Modifications for Titanium Implant Surfaces. Pharm Res 2008; 25:2357-69. [DOI: 10.1007/s11095-008-9617-0] [Citation(s) in RCA: 277] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 04/29/2008] [Indexed: 12/12/2022]
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69
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Haidar ZS, Hamdy RC, Tabrizian M. Protein release kinetics for core–shell hybrid nanoparticles based on the layer-by-layer assembly of alginate and chitosan on liposomes. Biomaterials 2008; 29:1207-15. [DOI: 10.1016/j.biomaterials.2007.11.012] [Citation(s) in RCA: 214] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 11/06/2007] [Indexed: 11/16/2022]
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70
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Sato S, Futakuchi M, Ogawa K, Asamoto M, Nakao K, Asai K, Shirai T. Transforming growth factor beta derived from bone matrix promotes cell proliferation of prostate cancer and osteoclast activation-associated osteolysis in the bone microenvironment. Cancer Sci 2008; 99:316-23. [PMID: 18271931 PMCID: PMC11158371 DOI: 10.1111/j.1349-7006.2007.00690.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Metastatic prostate tumors in the bone microenvironment stimulate bone resorption, resulting in release of growth factors from the bone matrix that play important roles in tumor growth and osteoclast induction. Transforming growth factor beta (TGFbeta) is one of the most abundantly stored cytokines in bone matrix, regulating diverse biological activities. Here we evaluate its involvement in prostate tumor growth in the bone microenvironment, comparing with tumor growth in the subcutaneous microenvironment as a control. Rat prostate tumors were transplanted onto the cranial bone and into the subcutis of F344 male rats. Tumor cell proliferation, apoptosis, and TGFbeta signal transduction were compared between the tumor-bone interface and the tumor-subcutaneous interface. Effects of TGFbeta on osteoclast differentiation were also evaluated in vitro. Inhibitory effects of TGFbeta receptor 1 antisense oligonucleotide on TGFbeta signaling, osteolysis, osteoblasts, and tumor growth were examined in vivo. Osteolytic changes were extensively observed at the tumor-bone interface, where the TGFbeta level, TGFbeta signal transduction, and tumor cell proliferation were higher than at the tumor-subcutaneous interface. In vitro treatment with receptor activator of nuclear factor-kappaB ligand induced osteoclast differentiation of bone marrow stromal cells, and additional exposure to TGFbeta exerted promotive effects on osteoclast induction. Intratumoral injection of TGFbeta receptor 1 antisense oligonucleotide significantly reduced TGFbeta signal transduction, osteolysis, induction of osteoclast and osteoblast, and tumor cell proliferation. Thus, we experimentally show that TGFbeta derived from bone matrix promotes cell proliferation of rat prostate cancer and osteoclast activation-associated osteolysis in the bone microenvironment.
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Affiliation(s)
- Shinya Sato
- Department of Experimental Pathology and Tumor Biology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
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71
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Hannink G, Piek E, Hendriks JMA, Van der Kraan PM, Schreurs BW, Buma P. Biological effects of rinsing morsellised bone grafts before and after impaction. INTERNATIONAL ORTHOPAEDICS 2008; 33:861-6. [PMID: 18200445 PMCID: PMC2903101 DOI: 10.1007/s00264-007-0513-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 11/29/2007] [Accepted: 12/02/2007] [Indexed: 11/30/2022]
Abstract
Rinsing bone grafts before or both before and after impaction might have different effects on the incorporation of the graft. Rinsing again after impaction might negatively influence bone induction if growth factors released by impaction are washed away. We studied if transforming growth factor-betas (TGF-betas) and bone morphogenetic proteins (BMPs) are released from the mineralised matrix by impaction and if these released growth factors induce osteogenic differentiation in human mesenchymal stem cells (hMSCs). Rinsed morsellised bone allografts were impacted in a cylinder and the escaping fluid was collected. The fluid was analysed for the presence of TGF-betas and BMPs, and the osteoinductive capacity was tested on hMSCs. Abundant TGF-beta was present in the fluid. No BMPs could be detected. Osteogenic differentiation of hMSCs was inhibited by the fluid. Results from our study leave us only able to speculate whether rinsing grafts again after impaction has a beneficial effect on the incorporation process or not.
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Affiliation(s)
- Gerjon Hannink
- Department of Orthopaedics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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72
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Insulin-like growth factor I releasing silk fibroin scaffolds induce chondrogenic differentiation of human mesenchymal stem cells. J Control Release 2007; 127:12-21. [PMID: 18280603 DOI: 10.1016/j.jconrel.2007.11.006] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 11/05/2007] [Accepted: 11/07/2007] [Indexed: 12/13/2022]
Abstract
Growth factor releasing scaffolds are an emerging alternative to autologous or allogenous implants, providing a biologically active template for tissue (re)-generation. The goal of this study is to evaluate the feasibility of controlled insulin-like growth factor I (IGF-I) releasing silk fibroin (SF) scaffolds in the context of cartilage repair. The impact of manufacturing parameters (pH, methanol treatment and drug load) was correlated with IGF-I release kinetics using ELISA and potency tests. Methanol treatment induced water insolubility of SF scaffolds, allowed the control of bioactive IGF-I delivery and did not affect IGF-I potency. The cumulative drug release correlated linearly with the IGF-I load. To evaluate the chondrogenic potential of the scaffolds, hMSC were seeded on unloaded and IGF-I loaded scaffolds in TGF-beta supplemented medium. Chondrogenic differentiation of hMSC was observed on IGF-I loaded scaffolds, starting after 2 weeks and more strongly after 3 weeks, whereas no chondrogenic responses were observed on unloaded control scaffolds. IGF-I loaded porous SF scaffolds have the potential to provide chondrogenic stimuli to hMSC. Evidence for in vivo cartilage (re)generation must be demonstrated by future, pre-clinical proof of concept studies.
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73
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Abstract
BACKGROUND Lymphedema delays the healing of any wound by negatively affecting its inflammatory period. Whether it affects bone healing in a similar negative manner is unknown. Therefore, we experimentally investigated the effect of lymphedema on fracture recovery. METHODS We used thirty 200- to 250-g Sprague-Dawley rats for the experiment. The rats were randomly divided into two groups of 15 rats each for the experimental lymphedema and control groups. Lymphedema development was confirmed by measuring the circumference and diameter of the extremities together with lymphoscintigraphy. Twenty days after the development of lymphedema, a fracture model was created in both groups in the right tibia with mid-diaphyseal osteotomy and fixing with an intramedullary Kirschner wire. After 6 weeks, all rats were sacrificed and the callus tissue that formed along the osteotomy was compared between groups with respect to radiographic, histological, and biomechanical characteristics. RESULTS The three-point bending test yielded an average stiffness value of 1227 N/mm (n = 6) in the control group and 284 N/mm (n = 7) in the experimental lymphedema group (P < 0.05). At the end of week 6, radiographic evaluation showed that solid knitting was obtained in the control group, whereas in the lymphedema group delayed or no knitting was observed. In the control group, histological investigation revealed normal callus morphology. Trabecular bone was normal and osteoblast and osteoclast activity was clearly evident. The bone was stained homogeneously with hematoxylin and eosin, and ossification was within normal limits. In the lymphedema group, however, the histological appearance was mostly that of scar tissue. In addition, osteoblast and osteoclast activity was much less visible or absent. CONCLUSIONS Lymphedema negatively affected bone healing in rats. However, the mechanism of this negative effect and its occurrence in humans are still unknown. Further experimental and clinical studies are needed to support and extend our findings.
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74
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Wildemann B, Kadow-Romacker A, Haas NP, Schmidmaier G. Quantification of various growth factors in different demineralized bone matrix preparations. J Biomed Mater Res A 2007; 81:437-42. [PMID: 17117475 DOI: 10.1002/jbm.a.31085] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Besides autografts, allografts, and synthetic materials, demineralized bone matrix (DBM) is used for bone defect filling and treatment of non-unions. Different DBM formulations are introduced in clinic since years. However, little is known about the presents and quantities of growth factors in DBM. Aim of the present study was the quantification of eight growth factors important for bone healing in three different "off the shelf" DBM formulations, which are already in human use: DBX putty, Grafton DBM putty, and AlloMatrix putty. All three DBM formulations are produced from human donor tissue but they differ in the substitutes added. From each of the three products 10 different lots were analyzed. Protein was extracted from the samples with Guanidine HCL/EDTA method and human ELISA kits were used for growth factor quantification. Differences between the three different products were seen in total protein contend and the absolute growth factor values but also a large variability between the different lots was found. The order of the growth factors, however, is almost comparable between the materials. In the three investigated materials FGF basic and BMP-4 were not detectable in any analyzed sample. BMP-2 revealed the highest concentration extractable from the samples with approximately 3.6 microg/g tissue without a significant difference between the three DBM formulations. In DBX putty significantly more TGF-beta1 and FGFa were measurable compared to the two other DBMs. IGF-I revealed the significantly highest value in the AlloMatrix and PDGF in Grafton. No differences were accessed for VEGF. Due to the differences in the growth factor concentration between the individual samples, independently from the product formulation, further analyzes are required to optimize the clinical outcome of the used demineralized bone matrix.
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Affiliation(s)
- B Wildemann
- Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Campus Virchow, Germany.
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75
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Ozkan K, Eralp L, Kocaoglu M, Ahishali B, Bilgic B, Mutlu Z, Turker M, Ozkan FU, Sahin K, Guven M. The effect of transforming growth factor beta1 (TGF-beta1) on the regenerate bone in distraction osteogenesis. Growth Factors 2007; 25:101-7. [PMID: 17891595 DOI: 10.1080/08977190701352594] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Distraction osteogenesis is a well established clinical treatment for limb length discrepancy and skeletal deformities. Transforming growth factor beta 1 (TGF-beta1) is a multifunctional peptide which controls proliferation and expression of cells specific to bone like chondrocytes, osteoblasts, osteoclasts including mesenchymal precursor cells. To decrease the external fixation time with increasing the strength of regenerate (newly formed bone after distraction) we tested the effect of locally applied transforming growth factor beta 1 on distraction osteogenesis. A total of 28 mature female white New zealand rabbits weighing 3,5 kg-4,5 kg were studied. 10 animals were belonging to biomechanical testing group (5 for the study and 5 for the control subgroups), and the others were to histology group. In biomechanical group after tibial osteotomy TGF-beta1 was applied subperiosteally for 5 days just proximal to osteotomy site. Control group received only the solvent. Seven days after tibial osteotomy distraction was started at a rate of 0.25 mm/12 hours for 3 weeks with a unilateral fixator. Rabbits were sacrificed at the end of a consolidation period 8 week after tibial osteotomy. We assessed density of the elongation zone of rabbit tibial bones with the computed tomography. Then biomechanical parametres were assessed using the torsional testing using the material testing machine. In histology group rabbits were classified as control and study (rabbits that were given TGF-beta1). Rabbits were sacrificed at the end of first week, second week and fourth week also at the end of consolidation period 8 week after tibial osteotomy. Immunohistochemical and histologic parameters were examined. Biomechanical testing was applied as torsional testing. These values are used in determination of maximal loading, stiffness and energy absorbed during testing (brittleness). The histomorphometric examination looked for the differences between the study and control groups in terms of bone formation pattern, bone quality and quantity. The immunohistochemical studies investigated the mechanism of TGF-beta1, and its presence in different cell types. The results of this study suggest that locally applied TGF-beta1 improves the mineral density of distraction gap and load to failure(energy absorbed during testing). Though there is no significant histomorphometric difference between the study and control groups, there is an increased bone mineral density and an according maximum energy absorbance in the study group. This effect can be explained by the following mechanism: TGF-beta1 exerts its effect on two different receptor types (Type 1 and 2). Type 1 receptors are localized to bone matrix and type 2 receptors are localized to the intracellular space. The specific stains utilized in the current experiment are specific to type 2 receptors. They have been shown to be down-regulated by exogenous TGF-beta1 injections. Most probably, type 1 receptors are up-regulated by this exogenous administration, but unfortunately, there is currently no specific stain on tha market to display type 1 receptors and to prove this explanation.
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Affiliation(s)
- Korhan Ozkan
- Department of Orthopedics and Traumatology, Goztepe Education and Research Hospital, Istanbul, Turkey.
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76
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Abstract
Fracture healing is a complex physiological process involving a coordinated interaction of hematopoietic and immune cells within the bone marrow, in conjunction with vascular and skeletal cell precursors. Multiple factors regulate this cascade of molecular events, which affects different stages in the osteoblast and chondroblast lineage during processes such as migration, proliferation, chemotaxis, differentiation, inhibition, and extracellular protein synthesis. A clear understanding of the cellular and molecular pathways in fracture healing is not only critical for advancing fracture treatment, but it may also enhance further our knowledge of the mechanisms involved within skeletal growth and repair, as well as the mechanisms of aging. An overview of the important molecules involved in fracture healing, including osteogenic autocoids and inhibitory molecules, and their interactions and possible mechanisms of synergy during the healing process is presented in this article.
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Affiliation(s)
- Eleftherios Tsiridis
- Academic Department of Trauma and Orthopaedic Surgery, St James's University Hospital, Beckett Street, Leeds, UK
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Villeneuve LAN, Gisbert E, Moriceau J, Cahu CL, Zambonino Infante JL. Intake of high levels of vitamin A and polyunsaturated fatty acids during different developmental periods modifies the expression of morphogenesis genes in European sea bass (Dicentrarchus labrax). Br J Nutr 2006; 95:677-87. [PMID: 16571146 DOI: 10.1079/bjn20051668] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of the feeding period on larval development was investigated in European sea bass larvae by considering the expression level of some genes involved in morphogenesis. Larvae were fed a control diet except during three different periods (period A: from 8 to 13 d post-hatching (dph); period B: from 13 to 18 dph; period C: from 18 to 23 dph) with two compound diets containing high levels of vitamin A or PUFA. European sea bass morphogenesis was affected by these two dietary nutrients during the early stages of development. The genes involved in morphogenesis could be modulated between 8 and 13 dph, and our results indicated that retinoids and fatty acids influenced two different molecular pathways that in turn implicated two different gene cascades, resulting in two different kinds of malformation. Hypervitaminosis A delayed development, reducing the number of vertebral segments and disturbing bone formation in the cephalic region. These malformations were correlated to an upregulation of retinoic acid receptor gamma, retinoid X receptor (RXR) alpha and bone morphogenetic protein (BMP)4. An excess of PUFA accelerated the osteoblast differentiation process through the upregulation of RXRalpha and BMP4, leading to a supernumerary vertebra. These results suggest that the composition of diets devoted to marine fish larvae has a particularly determining effect before 13 dph on the subsequent development of larvae and juvenile fish.
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Affiliation(s)
- Laure A N Villeneuve
- Centre d'Aqüicultura, Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Aptat. Correus 200, 43-540 Sant Carles de la Ràpita, Tarragona, Spain.
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78
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Everts PAM, Knape JTA, Weibrich G, Schönberger JPAM, Hoffmann J, Overdevest EP, Box HAM, van Zundert A. Platelet-rich plasma and platelet gel: a review. THE JOURNAL OF EXTRA-CORPOREAL TECHNOLOGY 2006; 38:174-87. [PMID: 16921694 PMCID: PMC4680757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Strategies to reduce blood loss and transfusion of allogeneic blood products during surgical procedures are important in modern times. The most important and well-known autologous techniques are preoperative autologous predonation, hemodilution, perioperative red cell salvage, postoperative wound blood autotransfusion, and pharmacologic modulation of the hemostatic process. At present, new developments in the preparation of preoperative autologous blood component therapy by whole blood platelet-rich plasma (PRP) and platelet-poor plasma (PPP) sequestration have evolved. This technique has been proven to reduce the number of allogeneic blood transfusions during open heart surgery and orthopedic operations. Moreover, platelet gel and fibrin sealant derived from PRP and PPP mixed with thrombin, respectively, can be exogenously applied to tissues to promote wound healing, bone growth, and tissue sealing. However, to our disappointment, not many well-designed scientific studies are available, and many anecdotic stories exist, whereas questions remain to be answered. We therefore decided to study perioperative blood management in more detail with emphasis on the application and production of autologous platelet gel and the use of fibrin sealant. This review addresses a large variety of aspects relevant to platelets, platelet-rich plasma, and the application of platelet gel. In addition, an overview of recent animal and human studies is presented.
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Affiliation(s)
- Peter A M Everts
- Department of Extra Corporeal Blood Management, Catharina Hospital, Eindhoven, The Netherlands.
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79
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Sánchez AR, Sheridan PJ, Eckert SE, Weaver AL. Regenerative potential of platelet-rich plasma added to xenogenic bone grafts in peri-implant defects: a histomorphometric analysis in dogs. J Periodontol 2006; 76:1637-44. [PMID: 16253084 DOI: 10.1902/jop.2005.76.10.1637] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The purpose of this investigation was to evaluate the regenerative influence of platelet-rich plasma (PRP) added to xenogenic bone grafts on bone histomorphometric parameters in a dog model. METHODS Ninety endosseous dental implants were inserted in the mandibles of nine hound dogs. Mesial and distal 3-wall peri-implant defects were surgically created adjacent to the implants. Defects were randomly assigned to three groups: demineralized freeze dried bone with platelet-rich plasma (DFDB + PRP), DFDB alone, and no treatment (NT). Animals were sacrificed at 1, 2, and 3 months according to a previously established randomization schedule, and specimens were subjected to histomorphometric analysis. Percentages of bone area inside the implant threads (BiIT), bone-to-implant contact (BIC), and bone area outside implant threads (BoIT) were recorded. Treatment effects were evaluated using analysis of variance models. RESULTS The effect of the three treatments on the outcome measures did not differ significantly by healing time (P > 0.05 for the healing time by treatment interaction). However, the average (standard deviation) percentage of BIC and BoIT was significantly different between the treatment groups. In particular, the average percentage of BIC differed between peri-implant defects treated with DFDB + PRP (33.8% [11.0]) and those treated with DFDB alone (28.5% [10.8]; P = 0.042), as well as those in the NT group (27.9% [11.0]; P = 0.024). Furthermore, the average percentage of BoIT differed significantly between defects treated with DFDB + PRP compared to defects in the NT group (51.6% [12.2] versus 43.3% [10.3]; P = 0.005). There was borderline evidence to suggest that the average percentage of BiIT and BIC was significantly different depending on the length of the healing time (P = 0.054 and P = 0.085, respectively). CONCLUSION This study found that the addition of PRP to xenogenic bone grafts demonstrated a low regenerative potential in this animal model.
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Affiliation(s)
- Andrés R Sánchez
- Division of Periodontics, Department of Dental Specialties, Mayo Clinic, Rochester, MN 55905, USA.
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80
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Duan K, Wang R. Surface modifications of bone implants through wet chemistry. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b517634d] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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81
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Dimitriou R, Tsiridis E, Giannoudis PV. Current concepts of molecular aspects of bone healing. Injury 2005; 36:1392-404. [PMID: 16102764 DOI: 10.1016/j.injury.2005.07.019] [Citation(s) in RCA: 604] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Revised: 06/24/2005] [Accepted: 07/21/2005] [Indexed: 02/02/2023]
Abstract
Fracture healing is a complex physiological process. It involves the coordinated participation of haematopoietic and immune cells within the bone marrow in conjunction with vascular and skeletal cell precursors, including mesenchymal stem cells (MSCs) that are recruited from the surrounding tissues and the circulation. Multiple factors regulate this cascade of molecular events by affecting different sites in the osteoblast and chondroblast lineage through various processes such as migration, proliferation, chemotaxis, differentiation, inhibition, and extracellular protein synthesis. An understanding of the fracture healing cellular and molecular pathways is not only critical for the future advancement of fracture treatment, but it may also be informative to our further understanding of the mechanisms of skeletal growth and repair as well as the mechanisms of aging.
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Affiliation(s)
- Rozalia Dimitriou
- Academic Department of Trauma and Orthopaedic Surgery, School of Medicine, University of Leeds, St James's University Hospital, Backett Street, LS9 7TF, UK
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82
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Damrongsri D, Geva S, Salvi GE, Williams RC, Limwongse V, Offenbacher S. Cyclooxygenase-2 inhibition selectively attenuates bone morphogenetic protein-6 synthesis and bone formation during guided tissue regeneration in a rat model. Clin Oral Implants Res 2005; 17:38-47. [PMID: 16441783 DOI: 10.1111/j.1600-0501.2005.01187.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Bone formation during guided tissue regeneration is a tightly regulated process involving cells, extracellular matrix and growth factors. The aims of this study were (i) to examine the expression of cyclooxygenase-2 (COX-2) during bone regeneration and (ii) the effects of selective COX-2 inhibition on osseous regeneration and growth factor expression in the rodent femur model. MATERIAL AND METHODS A standardized transcortical defect of 5 x 1.5 mm was prepared in the femur of 12 male rats and a closed half-cylindrical titanium chamber was placed over the defect. The expression of COX-2 and of platelet-derived growth factor-B (PDGF-B), bone morphogenetic protein-6 (BMP-6) and insulin-like growth factor-I/II (IGF-I/II) was analyzed at Days 3, 7, 21 and 28 semiquantitatively by reverse transcriptase-polymerase chain reaction and immunohistochemistry. The effects of COX-2 inhibition by intraperitoneal injection of NS-398 (3 mg/kg/day) were analyzed in five additional animals sacrificed at Day 14. RESULTS Histomorphometry revealed that new bone formation occurred in the cortical defect area as well as in the supracortical region, i.e. region within the chamber by Day 7 and increased through Day 28. Immunohistochemical evidence of COX-2 and PDGF-B levels were observed early (i.e. Day 3) and decreased rapidly by Day 7. BMP-6 expression was maximal at Day 3 and slowly declined by Day 28. In contrast, IGF-I/II expression gradually increased during the 28-day period. Systemic administration NS-398 caused a statistically significant reduction (P<0.05) in new bone formation (25-30%) and was associated with a statistically significant reduction in BMP-6 protein and mRNA expression (50% and 65% at P<0.05 and P<0.01, respectively). PDGF-B mRNA or protein expression was not affected by NS-398 treatment. CONCLUSION COX-2 inhibition resulted in reduced BMP-6 expression and impaired osseous regeneration suggesting an important role for COX-2-induced signaling in BMP synthesis and new bone formation.
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Affiliation(s)
- Damrong Damrongsri
- Department of Anatomy, School of Dentistry, Chulalongkorn University, Bangkok, Thailand
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83
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Luginbuehl V, Wenk E, Koch A, Gander B, Merkle HP, Meinel L. Insulin-like growth factor I-releasing alginate-tricalciumphosphate composites for bone regeneration. Pharm Res 2005; 22:940-50. [PMID: 15948038 DOI: 10.1007/s11095-005-4589-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Accepted: 02/22/2005] [Indexed: 12/13/2022]
Abstract
PURPOSE Development and characterization of an in situ-forming, osteoconductive, and growth factor-releasing bone implant. METHODS Injectable in situ-forming scaffolds were prepared from a 2% (m/v) alginate solution, tricalciumphosphate (TCP) granules, and poly(lactide-co-glycolide) microspheres (MS), loaded with the osteoinductive growth factor insulin-like growth factor I (IGF-I). Scaffolds were prepared by mixing the components followed by hydrogel formation through calcium carbonate-induced physical cross-linking of the alginate at slightly acidic pH. Physical-chemical properties and cell biocompatibility using osteoblast-like cells (MG-63 and Saos-2) of these scaffolds were investigated. RESULTS The addition of TCP to the alginate resulted in reduced swelling and gelation time and an increase in stiffness. Osteoblast-like cells (MG-63 and Saos-2) did not show toxic reactions and adhered circumferentially to the TCP granules surface. The addition of the IGF-I MS resulted in an up to sevenfold increased proliferation rate of MG-63 cells as compared to scaffold preparations without IGF-I MS. The alkaline phosphate (ALP) activity-a parameter for osteblastic activity-increased with increasing amounts of TCP in Saos-2 loaded composite scaffolds. CONCLUSIONS A prototype in situ-hardening composite system for conformal filling of bone defects supporting osteoblastic activity for further clinical testing in relevant fracture models was developed and characterized.
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Affiliation(s)
- Vera Luginbuehl
- Institute of Pharmaceutical Sciences, Drug Formulation and Delivery Group, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich, Switzerland
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84
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Henkel KO, Kirchhoff M, Neumann HG, Kundt G, Bienengräber V. Testung von Calciumsulfat-Bruschitzement als Knochenaufbaumaterial – In-vivo-Studie am Rattenkalottenmodell. ACTA ACUST UNITED AC 2005. [DOI: 10.1515/biomat.2005.6.1.14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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85
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Hing KA. Bone repair in the twenty-first century: biology, chemistry or engineering? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2004; 362:2821-2850. [PMID: 15539372 DOI: 10.1098/rsta.2004.1466] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Increases in reconstructive orthopaedic surgery, such as total hip replacement and spinal fusion, resulting from advances in surgical practice and the ageing population, have lead to a demand for bone graft that far exceeds supply. Consequently, a number of synthetic bone-graft substitutes (BGSs) have been developed with mixed success and surgical acceptance. Skeletal tissue regeneration requires the interaction of three basic elements: cells, growth factors (GFs) and a permissive scaffold. This can be achieved by pre-loading a synthetic scaffold with GFs or pre-expanded cells; however, a 'simpler' approach is to design intrinsic 'osteoinductivity' into your BGS, i.e. the capability to recruit and stimulate the patient's own GFs and stem cells. Through investigation of the mechanisms controlling bone repair in BGSs, linking interactions between the local chemical and physical environment, scientists are currently developing osteoinductive materials that can stimulate bone regeneration through control of the scaffold chemistry and structure. Moreover, this body of research is providing the foundations for future generations of BGSs and bone-repair therapies and may ultimately contribute towards improving the quality of life through maintenance of the skeleton and reversal of disease states, as opposed to the mending of broken bones that we currently practice. Will we be able to grow our own bones in a bioreactor for use as autologous graft materials in the future? Could surgery be limited to accidental trauma cases, with greater restoration of function through biochemical or gene therapies? The technology and research probes necessary to this task are currently being developed with the advent of nanotechnology, genomics and proteomics: are we about to embark on a chemical revolution in medicine? This paper aims to discuss some of the current thinking on the mechanisms behind bioactivity and biocompatibility in bone and how a fuller understanding of the interactions between cells and the materials used today could bring about completely new approaches for the treatment of bone fracture and disease tomorrow.
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Affiliation(s)
- Karin A Hing
- Interdisciplinary Research Centre in Biomedical Materials, Queen Mary, University of London, London E1 4NS, UK.
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86
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Cool SM, Snyman CP, Nurcombe V, Forwood M. Temporal expression of fibroblast growth factor receptors during primary ligament repair. Knee Surg Sports Traumatol Arthrosc 2004; 12:490-6. [PMID: 14691620 DOI: 10.1007/s00167-003-0444-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2003] [Accepted: 07/27/2003] [Indexed: 10/26/2022]
Abstract
Following injury, it is inherently difficult to completely restore the biomechanical properties of ligaments. Relatively little is known about the cellular mechanisms controlling ligament healing. Numerous studies have implicated fibroblast growth factors (FGFs) as key molecules during the initiation of the cellular proliferation, differentiation, migration and matrix deposition that characterise wound healing. While current surgical emphasis concentrates on growth factor intervention, the role of their cognate receptors (FGFRs) has largely been overlooked. Following transection of the medial collateral ligament (MCL) in rabbits, we examined FGFR expression over a 14-day healing period. Using semi-quantitative RT-PCR, we observed a significant upregulation in FGFR2 expression after 3 days. By 7 days post injury, FGFR2 expression fell to basal levels in line with those of FGFR1 and 3, both of which remained unaffected by surgical transection. These results demonstrate a role for FGFR2 in fibroblast and endothelial cell proliferation in damaged ligament, and suggest a window for FGF therapy.
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Affiliation(s)
- Simon M Cool
- School of Biomedical Sciences, University of Queensland, St. Lucia, 4072 Brisbane, Queensland, Australia.
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Kealey WDC, Lappin KJ, Leslie H, Sheridan B, Cosgrove AP. Endocrine profile and physical stature of children with Perthes disease. J Pediatr Orthop 2004; 24:161-6. [PMID: 15076600 DOI: 10.1097/00004694-200403000-00005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Children with Perthes disease have been thought to be of smaller stature than their peers. No reproducible evidence exists to demonstrate an endocrinopathy as the cause. This study reviewed 139 children with Perthes disease. Height and weight were recorded and compared with standardized growth charts. A blood sample was analyzed for thyroid stimulating hormone (TSH), thyroxin (T4), and insulin-like growth factor 1 (IGF1). Two urine samples were collected at 8 am and 8 pm within 24 hours. From these a cortisol/creatinine ratio was calculated. The results were compared with those from 40 healthy matched controls. No significant differences were found between the study or control children for levels of TSH, T4, IGF1, or cortisol. Review of the height and weight results revealed that the study children were of normal body habitus compared with the general pediatric population and do not undergo a period of growth acceleration following the active stages of the disease.
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88
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Chin D, Boyle GM, Parsons PG, Coman WB. What is transforming growth factor-beta (TGF-β)? ACTA ACUST UNITED AC 2004; 57:215-21. [PMID: 15006522 DOI: 10.1016/j.bjps.2003.12.012] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2002] [Accepted: 12/10/2003] [Indexed: 12/15/2022]
Abstract
The TGF-beta superfamily of proteins produces a wide range of frequently opposing effects in different cells and tissues in the body. However, its activation and mode of action are only partially understood because of its complexity in structure and functions and the variability in its downstream targets. Current work on these cytokines focuses on their receptors and the intercellular signalling pathways, comparing bioactivities between cell types and tracking their physiological and immunological effects in vivo. Future research will yield important therapeutic applications and the ability to manipulate these proteins in vivo.
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Affiliation(s)
- David Chin
- Melanoma Genomics and Head and Neck Group, Queensland Institute of Medical Research, Herston, QLD, Australia. davidCqimr.edu.au
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Raiche AT, Puleo DA. Cell responses to BMP-2 and IGF-I released with different time-dependent profiles. ACTA ACUST UNITED AC 2004; 69:342-50. [PMID: 15058007 DOI: 10.1002/jbm.a.30006] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During wound healing, growth factors are expressed in time-dependent amounts. Constant delivery of biomolecules, however, is often used to influence cell and tissue behavior. In the present studies, a crosslinked gelatin-coating system was used to deliver bone morphogenetic protein 2 (BMP-2) or insulin-like growth factor (IGF-I) to three types of mesenchymal cells with three temporally varying release profiles. The "early" delivery profile released most of the growth factor within the first 2 days. The "pseudo-zero-order" profile approximated constant rate of delivery for about 5 days. The "late" delivery profile released most of the growth factor after about 5 days. Early delivery of IGF-I had the greatest effect on mitogenesis of SaOS-2 human osteosarcoma cells with a secondary effect noted nearly 5 days after delivery was completed. Late delivery of BMP-2 resulted in greatest alkaline phosphatase (AP) activity in mouse pluripotent C3H10T1/2 cells. Rat bone marrow stromal cells (BMCs) responded to all delivery profiles of BMP-2, with the duration of elevated AP activity increasing as the amount of BMP-2 delivered increased. In addition to an early increase in AP activity, late release also stimulated BMCs over a longer portion of the culture period. BMCs responded similarly to SaOS-2 cells when seeded on early IGF-I delivery coatings, increasing AP activity after delivery had ended. Overall, these studies further show the importance of delivery profile, specifically the characteristics of time and concentration, on cell and tissue responses.
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Affiliation(s)
- A T Raiche
- Center for Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506-0070, USA
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90
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MURATA M, ARISUE M. De Novo Bone Formation Using Bovine Collagen and Platelet-rich Plasma in Animals. J HARD TISSUE BIOL 2004. [DOI: 10.2485/jhtb.13.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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91
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Foitzik C, Staus H. Le Fort I osteotomy in atrophied maxilla and bone regeneration with pure-phase beta-tricalcium phosphate and PRP. IMPLANT DENT 2003; 12:132-9. [PMID: 12861880 DOI: 10.1097/01.id.0000061084.09518.3e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Le Fort I osteotomy is a versatile procedure in oral and maxillofacial surgery for the correction of dysgnathias as well as for an easy approach to the surgical site in neurosurgery; however, it is rarely performed for a vertical advancement of the maxilla. This paper presents the successful use of the synthetic pure-phase beta-tricalcium phosphate (beta-TCP) Cerasorb (Curasan, Kleinostheim, Germany), together with autogenous bone at a ratio of 4:1, in combination with patients' own platelet-rich plasma for a vertical augmentation of completely atrophied maxillae, resulting in an advancement of 16 and 14 mm, respectively. After a period of 8 months the beta-TCP was completely resorbed and the x-ray control showed no residual granules in the defect sites. Pure-phase beta-TCP proved to be a bone-regeneration material, providing the patient with vital bone at the defect site in a reasonable time, making a second surgical procedure for bone harvesting (e.g., at the iliac crest) unnecessary. The relapse of approximately one third in the second case did not affect the success of treatment and was attributed to the combination of platelet-rich plasma with a resorbable polylactic membrane. Thus, in the combination of pure-phase beta-TCP and platelet-rich plasma, the use of nonresorbable membranes and suture materials is recommended. These results encourage the qualified surgeon to use the pure-phase beta-TCP for bone regeneration even when performing augmentations of this dimension.
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92
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Kokubu T, Hak DJ, Hazelwood SJ, Reddi AH. Development of an atrophic nonunion model and comparison to a closed healing fracture in rat femur. J Orthop Res 2003; 21:503-10. [PMID: 12706024 DOI: 10.1016/s0736-0266(02)00209-7] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although most fractures heal, some fail to heal and become nonunions. Many animal models have been developed to study problems of fracture healing. The majority of nonunion models have involved segmental bone defects, but this may not adequately represent the biologic condition in which nonunions clinically develop. The objective of the present study is to develop a nonunion model that better simulates the clinical situation in which there is soft tissue damage including periosteal disruption and to compare this model to a standard closed fracture model utilizing identical fracture stabilization, providing a similar mechanical environment. A total of 96 three month old Long Evans rats were utilized. A 1.25 mm diameter K-wire was inserted into the femur in a retrograde fashion, and a mid-diaphyseal closed transverse fracture was created using a standard three-point bending device. To create a nonunion, 48 of the rats received additional surgery to the fractured femur. The fracture site was exposed and 2 mm of the periosteum was cauterized on each side of the fracture. Fracture healing was evaluated with serial radiographs every two weeks. Animals were maintained for intervals of two, four, six or eight weeks after surgery. Specimens from each time interval were subjected to biomechanical and histological evaluation. None of the cauterized fractures healed throughout the eight weeks experimental duration. The radiographical appearance of nonunion models was atrophic. This investigation showed pronounced differences between the experimental nonunions and standard closed fractures both histologically and biomechanically. In conclusion, we have developed a reproducible atrophic nonunion model in the rat femur that simulates the clinical condition in which there is periosteal disruption but no bone defect.
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Affiliation(s)
- Takeshi Kokubu
- Department of Orthopaedic Surgery and Center for Tissue Regeneration and Repair, University of California, Davis, 4860 Y Street, Suite 3800, Sacramento 95817, USA
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93
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Wildemann B, Schmidmaier G, Ordel S, Stange R, Haas NP, Raschke M. Cell proliferation and differentiation during fracture healing are influenced by locally applied IGF-I and TGF-beta1: comparison of two proliferation markers, PCNA and BrdU. J Biomed Mater Res B Appl Biomater 2003; 65:150-6. [PMID: 12632384 DOI: 10.1002/jbm.b.10512] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Growth factors IGF-I and TGF-beta1 are known to stimulate fracture healing. The purpose of this study was to investigate the role of locally applied IGF-I and TGF-beta1 during the early phase of fracture healing (Days 5, 10, and 15 after fracture) on cellular processes like proliferation and differentiation in a rat model. Two different immunohistochemical markers were used to analyze cell proliferation: (1) injection of the thymidine analogue BrdU and subsequent immunohistochemical staining for BrdU-positive nuclei, and (2) the antibody against the "proliferating cell nuclear antigen" (PCNA). In comparison, both methods revealed similar results concerning the types of proliferating cells at the different time points and the two groups. Labeling indices of both methods showed very good correlation (e.g., r(s): 0.887 and p < 0.001 at day 10 in the control group without growth factors). Comparison of the callus morphology and the proliferation rate showed differences during fracture healing due to the local application of IGF-I and TGF-beta1 from coated implants. At Day 5 the callus of the group treated with growth factors displayed an earlier appearance of cartilage compared to the control group. This was accompanied by an onset of cell proliferation in chondrocytes. Likewise, at the later time points an enhanced maturation of the callus tissue and the proliferation pattern were detectable in the growth-factor group. These results indicate that local application of IGF-I and TGF-beta1 accelerates early cellular processes during fracture healing.
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Affiliation(s)
- B Wildemann
- Department of Trauma and Reconstructive Surgery, Charité, Campus Virchow, Humboldt-University of Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
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94
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Abstract
Musculoskeletal injuries have a significant human and financial impact on society. In particular, fractures that lead to delayed union or even nonunion represent a serious clinical challenge for which few treatment options are available. The multiple surgical procedures often needed are associated with patient morbidity and reduced quality of life. Biotechnological advances have made possible a host of potential treatments for enhancing and accelerating the repair of bone. By stimulating the body's own healing mechanisms, clinical outcomes may be improved while also containing procedural costs. Biotherapeutics may take the form of proteins, genes or cells that can be used to treat the injury. Protein biotherapeutics have received the greatest attention. Using recombinant DNA techniques, growth factors that play important roles in bone development and repair are being produced. By delivering exogenous growth factors to the site of injury in an appropriate manner, bone formation can be stimulated. Although individual proteins have been the primary focus of investigation, combinations of biomolecules can have additive, and perhaps synergistic, effects. Alternatively, genes coding for osteotropic growth factors can be delivered to the site of injury. Expression of the gene effectively results in localised delivery of the growth factor. Delivery of cells having osteogenic potential can also result in bone formation. Furthermore, it may be possible to obtain additional benefits by combining biotherapeutic approaches, such as by introducing cells genetically modified to overexpress therapeutic proteins of interest. Although biotherapeutics have great potential for stimulating bone repair, only a limited number of treatments have been approved by governmental regulatory agencies for clinical use. Bone morphogenetic activity was initially described in 1965, but not until 2001 and 2002 did two protein biotherapeutics, utilising bone morphogenetic proteins 2 and 7, receive approval for commercial distribution. Gene- and cell-based therapies are in a comparatively early stage of development.
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Affiliation(s)
- David Puleo
- Center for Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506-0070, USA.
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95
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Abstract
The cellular and molecular events governing bone formation in the embryo, healing of a fractured bone, and induced bone fusion follow a similar pattern. Discovery, purification, and recombinant synthesis of bone morphogenetic proteins (BMPs) constitute a major milestone in the understanding of bone physiology. In this review the author discusses the mechanism of action, clinical applications, dosage, and optimum carriers for BMPs. The roles played by other growth factors are also discussed.
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Affiliation(s)
- Setti S Rengachary
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit Medical Center, Detroit, Michigan, USA.
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96
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Eichner A, Brock J, Heldin CH, Souchelnytskyi S. Bone morphogenetic protein-7 (OP1) and transforming growth factor-beta1 modulate 1,25(OH)2-vitamin D3-induced differentiation of human osteoblasts. Exp Cell Res 2002; 275:132-42. [PMID: 11925111 DOI: 10.1006/excr.2002.5488] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bone morphogenetic proteins (BMPs) and transforming growth factor-beta (TGFbeta) are potent regulators of osteoblast differentiation and proliferation, processes that are crucial in bone remodeling. BMPs and TGFbeta act in concert with other local factors and hormones, among them 1,25(OH)2-vitamin D3 and insulin. Here we show that BMP7 inhibits 1,25(OH)2-vitamin D3-induced differentiation of human osteoblasts, whereas TGFbeta1 stimulates it, as assessed by assays for alkaline phosphatase (ALP) induction, matrix mineralization, and morphology changes. BMP7 or TGFbeta1 alone affects the differentiation of human osteoblasts. Similar results were obtained in assays for ALP induction using conditionally immortalized human osteoblasts (hFOB) and primary osteoblasts obtained from trabecular bone of the femoral head after hip replacement surgery. BMP7 stimulation led to a decrease of 1,25(OH)2-vitamin D3-induced binding of nuclear proteins to a vitamin D response element, as shown by electrophoretic mobility shift assay. Our results suggest that 1,25(OH)2-vitamin D3 modulates in opposite ways the effects of BMP7 and TGFbeta1 on osteoblast differentiation.
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97
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Cenni E, Granchi D, Vancini M, Pizzoferrato A. Platelet release of transforming growth factor-beta and beta-thromboglobulin after in vitro contact with acrylic bone cements. Biomaterials 2002; 23:1479-84. [PMID: 11829444 DOI: 10.1016/s0142-9612(01)00273-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Three methacrylate-based bone cements used for the fixation of joint prostheses were evaluated: Sulfix-60 (Sulzer Orthopedic Inc., Baar, Switzerland). CMW1 (DePuy International Ltd., England). and CMW2 (DePuy International Ltd., England). The cements after polymerization were put in contact in vitro with platelet-rich plasma. Plasma, in contact only with siliconized glass, was used as a negative control. After contact, platelet number. beta-thromboglobulin (beta-TG), and transforming growth factor-beta1 (TGF-beta1) were determined. The Student's paired t test showed that the ccments induced no significant modifications of platelet number. CMWI and Sulfix-60 determined a significant increase in beta-TG compared with the negative control. All cements determined a significant increase in TGF-beta1. Significant differences were also seen in the levels of beta-TG and TGF-beta1 between cements with a content of benzoyl peroxide < 1 (Sulfix-60) and those with a content > 1 (CMW1 and CMW2). The cement with zirconium dioxide (Sulfix-60) produced higher levels of beta-TG and TGF-beta1, compared to those with barium sulphate (CMW1 and CMW2). In conclusion, all the cements induced the secretion of TGF-beta1 CMW1 and Sulfix-60 determined also a significant release of beta-TG. Platelet activation induced by the cements from one side could contribute to the pathogenesis of deep venous thrombosis, that often occurs after prosthetic implant and is caused also by other factors, including surgical trauma and venous stasis. From the other side, activated platelets can release growth factors favoring bone formation.
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Affiliation(s)
- E Cenni
- Dipartimento Putti, Istituti Ortopedici Rizzoli, Bologna, Italy.
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98
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Schmidmaier G, Wildemann B, Stemberger A, Haas NP, Raschke M. Biodegradable poly(D,L-lactide) coating of implants for continuous release of growth factors. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 58:449-55. [PMID: 11410904 DOI: 10.1002/jbm.1040] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Local application of growth factors like insulin like growth factor-I (IGF-I) and transforming growth factor-beta 1 (TGF-beta1) from a biodegradable thin layer of poly(D,L-lactide) (PDLLA) coated implants could stimulate fracture healing. A new "cold coating technique" for metallic implants was established to produce a biodegradable coating with a high mechanical stability that provides a continuous release of incorporated growth factors. The properties of this bioactive coating were investigated in vitro and in vivo. Scanning electron microscope analysis revealed a coating thickness of in average 14.8 microm on titanium and 10.7 microm on steel wires. Intramedullary implantation and extraction experiments depicted a loss of PDLLA coating from titanium and steel implants of less than 5%. After explantation of the implants, the coating displayed a complete and regular layer without any defects of PDLLA uncovering the metallic surface. Smear tests demonstrate that the coating can be performed under sterile conditions. The PDLLA depicted a reduction of about 8% within 6 weeks in vitro and in vivo. The growth factors were incorporated in a stable form and demonstrated a loss of stability of less than 3% within 42 days and less than 5% within one year. In an elution experiment, 54% IGF-I and 48% TGF-beta1 were released within the first 48 h. After 42 days, 76% of IGF-I and 71% of TGF-beta1 were detected in the elution fluid by ELISA. Comparable results were obtained in the in vivo experiments after 42 days.
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Affiliation(s)
- G Schmidmaier
- Dept. of Trauma and Reconstructive Surgery, Charité, Humboldt-University of Berlin, Berlin, Germany.
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99
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Wang MY, Armstrong JK, Fisher TC, Meiselman HJ, McComb GJ, Levy ML. A new, pluronic-based, bone hemostatic agent that does not impair osteogenesis. Neurosurgery 2001; 49:962-7; discussion 968. [PMID: 11564259 DOI: 10.1097/00006123-200110000-00031] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2000] [Accepted: 05/02/2001] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Intraoperative bone hemostasis can be accomplished using surgical beeswax (bone wax). However, bone wax locally interferes with osteogenesis, and its use is avoided when bone fusion is critical. We describe the use of a Pluronic copolymer blend as a biocompatible, absorbable, hemostatic agent. METHODS A rat femur defect model and a femur gap nonunion model were used. For each surgical model, 24 rats were divided into three treatment groups, i.e., those receiving bone wax implants, Pluronic (90% Pluronic P85/10% Pluronic F88) implants, or no implants (control group). After 10, 21, or 42 days, animals were killed and femora were removed for radiographic analysis and hematoxylin and eosin staining. RESULTS In the femur defect model, no differences were observed between the Pluronic-treated and control groups; hematoxylin and eosin staining demonstrated bone formation and osteocytes within the defect. In the femur gap nonunion model, no fusions occurred in any group. Development of an osseous callus at the gap site was observed for the control and Pluronic-treated groups. In both models, rats that received bone wax implants exhibited no osseous growth. CONCLUSION The Pluronic blend exhibits handling properties similar to those of bone wax, readily achieves hemostasis, and does not inhibit bone regrowth. Pluronic compounds may serve as effective absorbable hemostatic agents for the treatment of bone bleeding in sites where fusion is critical. In addition, this copolymer blend may find use as a vehicle for the short-term release of pharmacological agents, which may further reduce the incidence of infections, reduce inflammation, and improve fusion rates.
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Affiliation(s)
- M Y Wang
- Division of Neurosurgery, Childrens Hospital of Los Angeles, 1200 NorthState Street, Los Angeles, CA 90033, USA.
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100
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Wang MY, Armstrong JK, Fisher TC, Meiselman HJ, McComb GJ, Levy ML. A New, Pluronic-based, Bone Hemostatic Agent That Does Not Impair Osteogenesis. Neurosurgery 2001. [DOI: 10.1227/00006123-200110000-00031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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