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Black C, Kanczler JM, de Andrés MC, White LJ, Savi FM, Bas O, Saifzadeh S, Henkel J, Zannettino A, Gronthos S, Woodruff MA, Hutmacher DW, Oreffo ROC. Characterisation and evaluation of the regenerative capacity of Stro-4+ enriched bone marrow mesenchymal stromal cells using bovine extracellular matrix hydrogel and a novel biocompatible melt electro-written medical-grade polycaprolactone scaffold. Biomaterials 2020; 247:119998. [PMID: 32251928 PMCID: PMC7184676 DOI: 10.1016/j.biomaterials.2020.119998] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 12/15/2022]
Abstract
Many skeletal tissue regenerative strategies centre around the multifunctional properties of bone marrow derived stromal cells (BMSC) or mesenchymal stem/stromal cells (MSC)/bone marrow derived skeletal stem cells (SSC). Specific identification of these particular stem cells has been inconclusive. However, enriching these heterogeneous bone marrow cell populations with characterised skeletal progenitor markers has been a contributing factor in successful skeletal bone regeneration and repair strategies. In the current studies we have isolated, characterised and enriched ovine bone marrow mesenchymal stromal cells (oBMSCs) using a specific antibody, Stro-4, examined their multipotential differentiation capacity and, in translational studies combined Stro-4+ oBMSCs with a bovine extracellular matrix (bECM) hydrogel and a biocompatible melt electro-written medical-grade polycaprolactone scaffold, and tested their bone regenerative capacity in a small in vivo, highly vascularised, chick chorioallantoic membrane (CAM) model and a preclinical, critical-sized ovine segmental tibial defect model. Proliferation rates and CFU-F formation were similar between unselected and Stro-4+ oBMSCs. Col1A1, Col2A1, mSOX-9, PPARG gene expression were upregulated in respective osteogenic, chondrogenic and adipogenic culture conditions compared to basal conditions with no significant difference between Stro-4+ and unselected oBMSCs. In contrast, proteoglycan expression, alkaline phosphatase activity and adipogenesis were significantly upregulated in the Stro-4+ cells. Furthermore, with extended cultures, the oBMSCs had a predisposition to maintain a strong chondrogenic phenotype. In the CAM model Stro-4+ oBMSCs/bECM hydrogel was able to induce bone formation at a femur fracture site compared to bECM hydrogel and control blank defect alone. Translational studies in a critical-sized ovine tibial defect showed autograft samples contained significantly more bone, (4250.63 mm3, SD = 1485.57) than blank (1045.29 mm3, SD = 219.68) ECM-hydrogel (1152.58 mm3, SD = 191.95) and Stro-4+/ECM-hydrogel (1127.95 mm3, SD = 166.44) groups. Stro-4+ oBMSCs demonstrated a potential to aid bone repair in vitro and in a small in vivo bone defect model using select scaffolds. However, critically, translation to a large related preclinical model demonstrated the complexities of bringing small scale reported stem-cell material therapies to a clinically relevant model and thus facilitate progression to the clinic.
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Affiliation(s)
- C Black
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development & Health, Institute of Developmental Sciences, University of Southampton, SO16 6YD, UK
| | - J M Kanczler
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development & Health, Institute of Developmental Sciences, University of Southampton, SO16 6YD, UK
| | - M C de Andrés
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development & Health, Institute of Developmental Sciences, University of Southampton, SO16 6YD, UK; Cartilage Epigenetics Group, Rheumatology Division, Biomedical Research Institute of A Coruña (INIBIC), Hospital Universitario de A Coruña-CHUAC, 15006 A Coruña ,Spain
| | - L J White
- School of Pharmacy, Biodiscovery Institute, University Park, University of Nottingham, Nottingham, NG7 2RD, UK
| | - F M Savi
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia; Institute of Health Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - O Bas
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia; Institute of Health Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - S Saifzadeh
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia
| | - J Henkel
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia
| | - A Zannettino
- Myeloma Research Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia and Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, Australia and Central Adelaide Local Health Network, Adelaide, South Australia, Australia
| | - S Gronthos
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia and Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - M A Woodruff
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia
| | - D W Hutmacher
- ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, QLD, 4059, Australia; Institute of Health Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - R O C Oreffo
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Human Development & Health, Institute of Developmental Sciences, University of Southampton, SO16 6YD, UK; College of Biomedical Engineering, China Medical University, Taichung, 40402, Taiwan.
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Gothard D, Smith EL, Kanczler JM, Rashidi H, Qutachi O, Henstock J, Rotherham M, El Haj A, Shakesheff KM, Oreffo ROC. Tissue engineered bone using select growth factors: A comprehensive review of animal studies and clinical translation studies in man. Eur Cell Mater 2014; 28:166-207; discussion 207-8. [PMID: 25284140 DOI: 10.22203/ecm.v028a13] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
There is a growing socio-economic need for effective strategies to repair damaged bone resulting from disease, trauma and surgical intervention. Bone tissue engineering has received substantial investment over the last few decades as a result. A multitude of studies have sought to examine the efficacy of multiple growth factors, delivery systems and biomaterials within in vivo animal models for the repair of critical-sized bone defects. Defect repair requires recapitulation of in vivo signalling cascades, including osteogenesis, chondrogenesis and angiogenesis, in an orchestrated spatiotemporal manner. Strategies to drive parallel, synergistic and consecutive signalling of factors including BMP-2, BMP-7/OP-1, FGF, PDGF, PTH, PTHrP, TGF-β3, VEGF and Wnts have demonstrated improved bone healing within animal models. Enhanced bone repair has also been demonstrated in the clinic following European Medicines Agency and Food and Drug Administration approval of BMP-2, BMP-7/OP-1, PDGF, PTH and PTHrP. The current review assesses the in vivo and clinical data surrounding the application of growth factors for bone regeneration. This review has examined data published between 1965 and 2013. All bone tissue engineering studies investigating in vivo response of the growth factors listed above, or combinations thereof, utilising animal models or human trials were included. All studies were compiled from PubMed-NCBI using search terms including 'growth factor name', 'in vivo', 'model/animal', 'human', and 'bone tissue engineering'. Focus is drawn to the in vivo success of osteoinductive growth factors incorporated within material implants both in animals and humans, and identifies the unmet challenges within the skeletal regenerative area.
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Affiliation(s)
- D Gothard
- Bone and Joint Research Group, Human Development and Health, University of Southampton, School of Medicine, Institute of Developmental Sciences, Mail Point 887, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD,
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Smith EL, Kanczler JM, Gothard D, Roberts CA, Wells JA, White LJ, Qutachi O, Sawkins MJ, Peto H, Rashidi H, Rojo L, Stevens MM, El Haj AJ, Rose FRAJ, Shakesheff KM, Oreffo ROC. Evaluation of skeletal tissue repair, part 2: enhancement of skeletal tissue repair through dual-growth-factor-releasing hydrogels within an ex vivo chick femur defect model. Acta Biomater 2014; 10:4197-205. [PMID: 24907660 DOI: 10.1016/j.actbio.2014.05.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/03/2014] [Accepted: 05/23/2014] [Indexed: 11/29/2022]
Abstract
There is an unmet need for improved, effective tissue engineering strategies to replace or repair bone damaged through disease or injury. Recent research has focused on developing biomaterial scaffolds capable of spatially and temporally releasing combinations of bioactive growth factors, rather than individual molecules, to recapitulate repair pathways present in vivo. We have developed an ex vivo embryonic chick femur critical size defect model and applied the model in the study of novel extracellular matrix (ECM) hydrogel scaffolds containing spatio-temporal combinatorial growth factor-releasing microparticles and skeletal stem cells for bone regeneration. Alginate/bovine bone ECM (bECM) hydrogels combined with poly(d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PLDLGA) microparticles releasing dual combinations of vascular endothelial growth factor (VEGF), chondrogenic transforming growth factor beta 3 (TGF-β3) and the bone morphogenetic protein BMP2, with human adult Stro-1+bone marrow stromal cells (HBMSCs), were placed into 2mm central segmental defects in embryonic day 11 chick femurs and organotypically cultured. Hydrogels loaded with VEGF combinations induced host cell migration and type I collagen deposition. Combinations of TGF-β3/BMP2, particularly with Stro-1+HBMSCs, induced significant formation of structured bone matrix, evidenced by increased Sirius red-stained matrix together with collagen expression demonstrating birefringent alignment within hydrogels. This study demonstrates the successful use of the chick femur organotypic culture system as a high-throughput test model for scaffold/cell/growth factor therapies in regenerative medicine. Temporal release of dual growth factors, combined with enriched Stro-1+HBMSCs, improved the formation of a highly structured bone matrix compared to single release modalities. These studies highlight the potential of a unique alginate/bECM hydrogel dual growth factor release platform for bone repair.
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Affiliation(s)
- E L Smith
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK.
| | - J M Kanczler
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - D Gothard
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - C A Roberts
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - J A Wells
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - L J White
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - O Qutachi
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - M J Sawkins
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - H Peto
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - H Rashidi
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - L Rojo
- Department of Materials, Imperial College London, London, UK; Institute for Biomedical Engineering, Imperial College London, London, UK; Institute of Polymer Science & Technology, CSIC and CIBER-BBN, Madrid, Spain
| | - M M Stevens
- Department of Materials, Imperial College London, London, UK; Institute for Biomedical Engineering, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - A J El Haj
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Newcastle-under-Lyme, UK
| | - F R A J Rose
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK
| | - K M Shakesheff
- The Wolfson Centre for Stem Cells, Tissue Engineering & Modelling (STEM), School of Pharmacy, University of Nottingham, Nottingham, UK.
| | - R O C Oreffo
- Bone & Joint Research Group, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK.
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Bolland BJRF, Kanczler JM, Dunlop DG, Oreffo ROC. Development of in vivo muCT evaluation of neovascularisation in tissue engineered bone constructs. Bone 2008; 43:195-202. [PMID: 18424249 DOI: 10.1016/j.bone.2008.02.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 02/08/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
Due to an increasing aging population the need for innovative approaches to aid skeletal repair and reconstruction is a significant socio-economic increasing problem. The emerging discipline of tissue engineering has sort to augment the growth and repair of bone loss particularly in areas of trauma, degeneration and revision surgery. However, the initiation and development of a fully functional vascular network are critical for bioengineered bone to repair large osseous defects, whether the material is osteosynthetic (poly (d,l)-lactic acid, PLA) or natural bone allograft. Quantification and three-dimensional visualization of new vessel networks remain a problem in bone tissue engineering constructs. A novel technique utilising a radio-opaque dye and micro-computed tomography (muCT) has been developed and applied to study angiogenesis in an impaction bone graft model. Tissue-engineered constructs combining human bone marrow stromal cells (HBMSC) with natural allograft and synthetic grafts (PLA) were impacted and implanted into the subcutis of MF-1 nu/nu mice for a period of 28 days. Microfil consisting of radio-opaque polymer was perfused through the mice and scanned using a Bench Top CT system for micro-computed tomography. Analysis of three-dimensional muCT reconstructions demonstrated an increase in vessel volume and vessel number in the impacted scaffolds/HBMC compared to scaffolds alone. Vessel volume: allograft/HBMSC=0.57 mm(3)+/-0.19; allograft=0.04 mm(3)+/-0.04; PLA/HBMSC=1.19 mm(3)+/-0.31; and PLA=0.12 mm(3)+/-0.01. Penetrating vessel number: allograft/HBMSC=22.33+/-3.21; allograft=3.67+/-1.153; PLA/HBMSC=32.67+/-8.33; and PLA=7.67+/-3.06. Type 1 collagen and von Willebrand factor immunohistochemistry in scaffold/HBMSC constructs indicated the osteogenic cell phenotype, and new blood vessel formation respectively. Contrast-enhanced 3D reconstructions facilitated the visualization and quantification of neovascularisation. This novel technique has been used to demonstrate neovascularisation in impacted tissue engineered constructs providing a facile approach with wide experimental application.
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Affiliation(s)
- B J R F Bolland
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD, UK
| | - J M Kanczler
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD, UK
| | - D G Dunlop
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD, UK
| | - R O C Oreffo
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD, UK.
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Abstract
The repair of large bone defects remains a major clinical orthopaedic challenge. Bone is a highly vascularised tissue reliant on the close spatial and temporal connection between blood vessels and bone cells to maintain skeletal integrity. Angiogenesis thus plays a pivotal role in skeletal development and bone fracture repair. Current procedures to repair bone defects and to provide structural and mechanical support include the use of grafts (autologous, allogeneic) or implants (polymeric or metallic). These approaches face significant limitations due to insufficient supply, potential disease transmission, rejection, cost and the inability to integrate with the surrounding host tissue. The engineering of bone tissue offers new therapeutic strategies to aid musculoskeletal healing. Various scaffold constructs have been employed in the development of tissue-engineered bone; however, an active blood vessel network is an essential pre-requisite for these to survive and integrate with existing host tissue. Combination therapies of stem cells and polymeric growth factor release scaffolds tailored to promote angiogenesis and osteogenesis are under evaluation and development actively to stimulate bone regeneration. An understanding of the cellular and molecular interactions of blood vessels and bone cells will enhance and aid the successful development of future vascularised bone scaffold constructs, enabling survival and integration of bioengineered bone with the host tissue. The role of angiogenic and osteogenic factors in the adaptive response and interaction of osteoblasts and endothelial cells during the multi step process of bone development and repair will be highlighted in this review, with consideration of how some of these key mechanisms can be combined with new developments in tissue engineering to enable repair and growth of skeletal fractures. Elucidation of the processes of angiogenesis, osteogenesis and tissue engineering strategies offer exciting future therapeutic opportunities for skeletal repair and regeneration in orthopaedics.
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Affiliation(s)
- J M Kanczler
- Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Developmental Origins of Health and Disease, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD,
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Kanczler JM, Barry J, Ginty P, Howdle SM, Shakesheff KM, Oreffo ROC. Supercritical carbon dioxide generated vascular endothelial growth factor encapsulated poly(DL-lactic acid) scaffolds induce angiogenesis in vitro. Biochem Biophys Res Commun 2006; 352:135-41. [PMID: 17112464 DOI: 10.1016/j.bbrc.2006.10.187] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 10/31/2006] [Indexed: 12/16/2022]
Abstract
The ability to deliver, over time, biologically active vascular endothelial growth factor-165 (VEGF) through tailored designed scaffolds offers tremendous therapeutic opportunities to tissue-engineered therapies. Porous biodegradable poly(DL-lactic) acid (PLA) scaffolds encapsulating VEGF have been generated using supercritical CO2 (scCO2) and the kinetic release and angiogenic activity of these scaffolds examined in vitro and in an ex vivo chick chorioallantoic membrane (CAM) angiogenesis model. After processing through scCO2, VEGF maintained its angiogenic activity as assessed by increased tubule formation of human umbilical vein endothelial cells (HUVEC) cultured on Matrigel (VEGF = 1937 +/- 205 microm; scCO2-VEGF = 2085 +/- 234 microm; control = 1237 +/- 179 microm). VEGF release kinetics from scCO2-VEGF incorporated PLA monolith scaffolds showed a cumulative release of VEGF (2837 +/- 761 rhog/ml) over a 21 day period in culture. In addition, VEGF encapsulated PLA scaffolds increased the blood vessel network in the CAM compared to controls; control, 24.8 +/- 9.6; VEGF/PLA, 44.1 +/- 12.1 (vessels/field). These studies demonstrate that the controlled release of growth factors encapsulated into three-dimensional PLA scaffolds can actively stimulate the rapid development of therapeutic neovascularisation to regenerate or engineer tissues.
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Affiliation(s)
- J M Kanczler
- Bone and Joint Research Group, Developmental Origins of Health and Disease, University of Southampton, Southampton SO166YD, UK
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Abstract
Formula-fed babies contract gastroenteritis more than breast-fed babies, which is of concern to mothers who cannot breastfeed or, as with HIV-infected mothers, are discouraged from breastfeeding. The ability of endogenous breastmilk xanthine oxidase to generate the antimicrobial radical nitric oxide has been measured and its influence on the growth of Escherichia coli and Salmonella enteritides examined. Breastmilk, but not formula feed, generated nitric oxide. Xanthine oxidase activity substantially inhibited the growth of both bacteria. An important natural antibiotic system is missing in formula feeds; the addition of xanthine oxidase may improve formula for use when breastfeeding is not a safe option.
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Bodamyali T, Kanczler JM, Simon B, Blake DR, Stevens CR. Effect of faradic products on direct current-stimulated calvarial organ culture calcium levels. Biochem Biophys Res Commun 1999; 264:657-61. [PMID: 10543988 DOI: 10.1006/bbrc.1999.1355] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calcium release from mouse calvarial organ cultures was used to analyse the well-described biological effects of constant direct current (20 microA) in combination with Faradic products generated at a titanium wire cathode. Constant 20-microA direct current stimulation alone, delivered by agar salt bridges, consistently lowered the media calcium levels. Direct exposure of calvariae to a titanium cathode and its faradic products resulted in further lowering of media calcium levels and also a significant increase in the media pH. Hydrogen peroxide is a faradic product of the titanium cathode, micromolar amounts being generated by our system over 24 hr. H(2)O(2) is pro-resorptive whereas elevated pH stimulates osteoblast activity. We propose that where bone tissue is in direct contact with metal wire cathodes, the faradic products, hydrogen peroxide and hydroxyl ion, are significant factors which, in their own right, further contribute to accelerated remodelling and improved clinical outcome.
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Affiliation(s)
- T Bodamyali
- School of Postgraduate Medicine, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
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Bodamyali T, Bhatt B, Hughes FJ, Winrow VR, Kanczler JM, Simon B, Abbott J, Blake DR, Stevens CR. Pulsed electromagnetic fields simultaneously induce osteogenesis and upregulate transcription of bone morphogenetic proteins 2 and 4 in rat osteoblasts in vitro. Biochem Biophys Res Commun 1998; 250:458-61. [PMID: 9753652 DOI: 10.1006/bbrc.1998.9243] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Pulsed electromagnetic fields (PEMF) are successfully employed in the treatment of a variety of orthopaedic conditions, particularly delayed and nonunion fractures. In this study, we examined PEMF effects on in vitro osteogenesis by bone nodule formation and on mRNA expression of bone morphogenetic proteins 2 and 4 by reverse-transcriptase polymerase chain reaction (RT-PCR) in cultured rat calvarial osteoblasts. PEMF exposure induced a significant increase in both the number (39% over unexposed controls) and size (70% larger compared to unexposed controls) of bone-like nodules formed. PEMF also induced an increase in the levels of BMP-2 and BMP-4 mRNA in comparison to controls. This effect was directly related to the duration of PEMF exposure. This study shows that clinically applied PEMF have a reproducible osteogenic effect in vitro and simultaneously induce BMP-2 and -4 mRNA transcription. This supports the concept that the two effects are related.
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Affiliation(s)
- T Bodamyali
- School of Postgraduate Medicine, University of Bath, Claverton Down, United Kingdom
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Zhang Z, Blake DR, Stevens CR, Kanczler JM, Winyard PG, Symons MC, Benboubetra M, Harrison R. A reappraisal of xanthine dehydrogenase and oxidase in hypoxic reperfusion injury: the role of NADH as an electron donor. Free Radic Res 1998; 28:151-64. [PMID: 9645392 DOI: 10.3109/10715769809065801] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Xanthine oxidase (XO) is conventionally known as a generator of reactive oxygen species (ROS) which contribute to hypoxic-reperfusion injury in tissues. However, this role for human XO is disputed due to its distinctive lack of activity towards xanthine, and the failure of allopurinol to suppress reperfusion injury. In this paper, we have employed native gel electrophoresis together with activity staining to investigate the role human xanthine dehydrogenase (XD) and XO in hypoxic reperfusion injury. This approach has provided information which cannot be obtained by conventional spectrophotometric assays. We found that both XD and XO of human umbilical vein endothelial cells (HUVECs) and lymphoblastic leukaemic cells (CEMs) catalysed ROS generation by oxidising NADH, but not hypoxanthine. The conversion of XD to XO was observed in both HUVECs and CEMs in response to hypoxia, although the level of conversion varied. Purified human milk XD generated ROS more efficiently in the presence of NADH than in the presence of hypoxanthine. This NADH oxidising activity was blocked by the FAD site inhibitor, diphenyleneiodonium (DPI), but was not suppressible by the molybdenum site inhibitor, allopurinol. However, in the presence of both DPI and allopurinol the activities of XD/XO were completely blocked with either NADH or hypoxanthine as substrates. We conclude that both human XD and XO can oxidise NADH to generate ROS. Therefore, the conversion of XD to XO is not necessary for post-ischaemic ROS generation. The hypoxic-reperfusion injury hypothesis should be reappraised to take into account the important role played by XD and XO in oxidising NADH to yield ROS.
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Affiliation(s)
- Z Zhang
- Bone and Joint Research Unit, St Bartholomew's and the Royal London School of Medicine and Dentistry, University of London, UK.
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Reape TJ, Wilson VJ, Kanczler JM, Ward JP, Burnand KG, Thomas CR. Detection and cellular localization of heparin-binding epidermal growth factor-like growth factor mRNA and protein in human atherosclerotic tissue. J Mol Cell Cardiol 1997; 29:1639-48. [PMID: 9220349 DOI: 10.1006/jmcc.1997.0399] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family which binds to and activates the epidermal growth factor (EGF) receptor. HB-EGF mRNA is expressed by monocytes and vascular smooth muscle cells (VSMC) in culture, and has been shown to be a potent VSMC mitogen in vitro. The aim of this study was to screen normal and human atherosclerotic arteries and SMC cultured from these arteries for expression of HB-EGF, and to determine its cellular localization in human lesions. Using the highly sensitive technique of reverse transcription polymerase chain reaction (RT-PCR), we screened biopsies taken from normal human vessel walls and atherosclerotic tissue, for expression of HB-EGF mRNA. Northern blotting and RT-PCR were employed to determine levels of HB-EGF gene expression in SMC, cultured from normal and atherosclerotic arteries. Cellular localization of mRNA and protein, within human atherosclerotic plaques, was assessed using in situ hybridization with 35S labelled riboprobes, and immunohistochemistry with polyclonal antibodies specific for human HB-EGF. HB-EGF mRNA was found to be expressed in human atherosclerotic lesions and in VSMC cultured from these lesions. Expression of HB-EGF could not be detected in quiescent aortic VSMC using Northern blotting, but was highly up-regulated in these cells after treatment with basic fibroblast growth factor (bFGF) for 24 h. Although HB-EGF mRNA was detected in all vascular tissue examined using RT-PCR, in situ hybridization and immunohistochemistry revealed expression of HB-EGF in small portions of diseased arteries only. Immunohistochemistry showed strong staining for macrophages in all areas of HB-EGF expression. No association of HB-EGF with SMC was observed in any of the specimens examined. In conclusion, HB-EGF, a potent mitogen for VSMC, is expressed by macrophages in human.
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Affiliation(s)
- T J Reape
- Department of Medicine, U.M.D.S., St Thomas' Hospital, London, UK
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Reape TJ, Kanczler JM, Ward JP, Thomas CR. IGF-I increases bFGF-induced mitogenesis and upregulates FGFR-1 in rabbit vascular smooth muscle cells. Am J Physiol 1996; 270:H1141-8. [PMID: 8967350 DOI: 10.1152/ajpheart.1996.270.4.h1141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor (bFGF) have both been implicated in the abnormal proliferation of vascular smooth muscle cells (VSMC) that occurs after injury to the arterial wall in vivo. We have investigated the effects of these growth factors on proliferation of rabbit aortic smooth muscle cells (RASMC) in vitro. IGF-I, in contrast to bFGF, is a weak mitogen for RASMC. However, when IGF-I (10 ng/ml) was added in combination with bFGF for 24 h, the effect of the two growth factors on DNA synthesis was synergistic at all concentrations tested (P > 0.001 compared with summed values of bFGF alone plus IGF-I alone), and this synergy was also observed at the level of RASMC proliferation (P < 0.001). Time-course experiments indicated that although bFGF was able to stimulate DNA synthesis after 16 h, activity peaked at 24 h, and a synergistic response with IGF-I was not observed before 24 h. Northern blot analysis demonstrated that IGF-I (10 ng/ml) could selectively upregulate fibroblast growth factor receptor-1 (FGFR-1) mRNA 4.0 +/- 0.24-fold (P < 0.001) without a significant effect on FGFR-2, and this induction in FGFR-1 mRNA occurs in a time- and dose-dependent manner. In addition, IGF-I increases FGFR-1 protein levels in RASMC 2.7 +/- 0.12-fold (P < 0.01), as demonstrated by Western blotting, and this upregulation occurs before the peak in DNA synthesis. These results suggest that IGF-I may be capable of increasing the responsiveness of VSMC to bFGF through modulation of FGFR-1.
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MESH Headings
- Animals
- Aorta/cytology
- Aorta/metabolism
- Cell Division/drug effects
- Cells, Cultured
- DNA/biosynthesis
- Fibroblast Growth Factor 2/pharmacology
- Insulin-Like Growth Factor I/pharmacology
- Male
- Mitosis/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- RNA, Messenger/metabolism
- Rabbits
- Receptor Protein-Tyrosine Kinases
- Receptor, Fibroblast Growth Factor, Type 1
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/metabolism
- Up-Regulation
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Affiliation(s)
- T J Reape
- Department of Medicine, United Medical School, St. Thomas's Hospital, London, United Kingdom
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