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Matsumoto T, Sato S. Stimulating angiogenesis mitigates the unloading-induced reduction in osteogenesis in early-stage bone repair in rats. Physiol Rep 2015; 3:e12335. [PMID: 25780087 PMCID: PMC4393168 DOI: 10.14814/phy2.12335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 02/17/2015] [Accepted: 02/17/2015] [Indexed: 11/24/2022] Open
Abstract
Accelerating fracture healing during bed rest allows early mobilization and avoids prolonged fracture healing times. We tested the hypothesis that stimulating angiogenesis with deferoxamine (DFO) mitigates the unloading-induced reduction in early-stage bone repair. Rats aged 12 weeks were subjected to cortical drilling on their tibial diaphysis under anesthesia and treated with hindlimb unloading (HU), HU and DFO administration (DFOHU), or weight bearing (WB) for 5 or 10 days (HU5/10, DFOHU5/10, WB5/10; n = 8 per groups) until sacrifice for vascular casting with a zirconium dioxide-based contrast agent. Taking advantage of its absorption discontinuity at the K-absorption edge, vascular and bone images in the drill-hole defects were acquired by synchrotron radiation subtraction CT. Bone repair was reduced in HU rats. The bone volume fraction (B.Vf) was 88% smaller in HU5 and 42% smaller in HU10 than in WB5/10. The bone segment densities (B.Seg) were 97% smaller in HU5 and 141% larger in HU10 than in WB5/10, and bone thickness (B.Th) was 38% smaller in HU10 than in WB10. The vascular volume fraction (V.Vf) was 35% and the mean vessel diameter (V.D) was 13% smaller in HU10 than in WB10. When compared according to categorized vessel sizes, V.Vf in the diameter ranges 20-30, 30-40, and >40 μm were smaller in HU10 than in WB10, and V.Seg in the diameter range >40 μm was smaller in HU10 than in WB10. In contrast, there was no difference in B.Vf between DFOHU5/10 and WB5/10 and in V.Vf between DFOHU10 and WB10, though B.Seg remained 86% smaller in DFOHU5 and 94% larger in DFOHU10 than in WB5/10, and B.Th and V.D were 23% and 14% lower in DFOHU10 than in WB10. Vessel size-specific V.Vf in the diameter ranges 10-20 and 20-30 μm was larger in DFOHU5 than in HU5. In conclusion, the enhanced angiogenic ingrowth mitigates the reduction in bone repair during mechanical unloading.
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Affiliation(s)
- Takeshi Matsumoto
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Toyonaka, Japan
| | - Shota Sato
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Toyonaka, Japan
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Gilbert SR, Camara J, Camara R, Duffy L, Waites K, Kim H, Zinn K. Contaminated open fracture and crush injury: a murine model. Bone Res 2015; 3:14050. [PMID: 26273534 PMCID: PMC4472147 DOI: 10.1038/boneres.2014.50] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/16/2014] [Accepted: 12/27/2014] [Indexed: 12/27/2022] Open
Abstract
Modern warfare has caused a large number of severe extremity injuries, many of which become infected. In more recent conflicts, a pattern of co-infection with Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus has emerged. We attempted to recreate this pattern in an animal model to evaluate the role of vascularity in contaminated open fractures. Historically, it has been observed that infected bones frequently appear hypovascular, but vascularity in association with bone infection has not been examined in animal models. Adult rats underwent femur fracture and muscle crush injury followed by stabilization and bacterial contamination with A. baumannii complex and methicillin-resistant Staphylococcus aureus. Vascularity and perfusion were assessed by microCT angiography and SPECT scanning, respectively, at 1, 2 and 4 weeks after injury. Quantitative bacterial cultures were also obtained. Multi-bacterial infections were successfully created, with methicillin-resistant S. aureus predominating. There was overall increase in blood flow to injured limbs that was markedly greater in bacteria-inoculated limbs. Vessel volume was greater in the infected group. Quadriceps atrophy was seen in both groups, but was greater in the infected group. In this animal model, infected open fractures had greater perfusion and vascularity than non-infected limbs.
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Affiliation(s)
- Shawn R Gilbert
- Department of Surgery, University of Alabama at Birmingham , AL USA
| | | | | | - Lynn Duffy
- Departments of Pathology, University of Alabama at Birmingham , AL USA
| | - Ken Waites
- Departments of Pathology, University of Alabama at Birmingham , AL USA
| | - Hyunki Kim
- Department of Radiology, University of Alabama at Birmingham , AL USA
| | - Kurt Zinn
- Department of Radiology, University of Alabama at Birmingham , AL USA
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Stegen S, van Gastel N, Carmeliet G. Bringing new life to damaged bone: the importance of angiogenesis in bone repair and regeneration. Bone 2015; 70:19-27. [PMID: 25263520 DOI: 10.1016/j.bone.2014.09.017] [Citation(s) in RCA: 294] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 09/14/2014] [Accepted: 09/18/2014] [Indexed: 12/26/2022]
Abstract
Bone has the unique capacity to heal without the formation of a fibrous scar, likely because several of the cellular and molecular processes governing bone healing recapitulate the events during skeletal development. A critical component in bone healing is the timely appearance of blood vessels in the fracture callus. Angiogenesis, the formation of new blood vessels from pre-existing ones, is stimulated after fracture by the local production of numerous angiogenic growth factors. The fracture vasculature not only supplies oxygen and nutrients, but also stem cells able to differentiate into osteoblasts and in a later phase also the ions necessary for mineralization. This review provides a concise report of the regulation of angiogenesis by bone cells, its importance during bone healing and its possible therapeutic applications in bone tissue engineering. This article is part of a Special Issue entitled "Stem Cells and Bone".
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Affiliation(s)
- Steve Stegen
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, 3000 Leuven, Belgium
| | - Nick van Gastel
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, 3000 Leuven, Belgium
| | - Geert Carmeliet
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, 3000 Leuven, Belgium.
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Prolyl hydroxylase inhibitors protect from the bone loss in ovariectomy rats by increasing bone vascularity. Cell Biochem Biophys 2014; 69:141-9. [PMID: 24242187 DOI: 10.1007/s12013-013-9780-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway is involved in skeletal development, bone repair, and postmenopausal osteoporosis. Inhibitors of prolyl hydroxylases (PHD) enhance vascularity, increase callus formation in a stabilized fracture model, and activate the HIF-1α/VEGF pathway. This study examined the effects of estrogen on the HIF-1α/VEGF pathway in osteoblasts and whether PHD inhibitors can protect from bone loss in postmenopausal osteoporosis. Osteoblasts were treated with estrogen, and expressions of HIF-1α and VEGF were measured at mRNA (qPCR) and protein (Western blot) levels. Further, osteoblasts were treated with inhibitors of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, and levels of VEGF mRNA and protein expression were detected. In addition, ovariectomized rats were treated with PHD inhibitors, and bone microarchitecture and bone mechanical strength were assessed using micro-CT and biomechanical analyses (lower ultimate stress, modulus, and stiffness). Blood vessel formation was measured with India Ink Perfusion and immunohistochemistry. Estrogen, in a dose- and time-dependent manner, induced VEGF expression at both mRNA and protein levels and enhanced HIF-1α protein stability. Further, the estrogen-induced VEGF expression in osteoblasts involved the PI3K/Akt pathway. PHD inhibitors increased bone mineral density, bone microarchitecture and bone mechanical strength, and promoted blood vessel formation in ovariectomized rats. In conclusion, estrogen and PHD inhibitors activate the HIF-1α/VEGF pathway in osteoblasts. PHD inhibitors can be utilized to protect bone loss in postmenopausal osteoporosis by improving bone vascularity and angiogenesis in bone marrow.
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Restoring the secretory function of irradiation-damaged salivary gland by administrating deferoxamine in mice. PLoS One 2014; 9:e113721. [PMID: 25427160 PMCID: PMC4245233 DOI: 10.1371/journal.pone.0113721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 10/28/2014] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES One of the major side effects of radiotherapy for treatments of the head and neck cancer is the radiation-induced dysfunction of salivary glands. The aim of the present study is to investigate the efficacy of deferoxamine (DFO) to restore the secretory function of radiation-damaged salivary glands in mice. METHODS DFO (50 mg/kg/d) was administered intraperitoneally in C57BL/6 mice for 3 days before and/or after point-fixed irradiation (18 Gy) of submandibular glands. The total 55 mice were randomly divided into: (1) Normal group: mice received no treatment (n = 5); (2) Irradiation group (IR): mice only received irradiation (n = 5); (3) Pre-DFO group (D+IR) (n = 10); (4) Pre+Post DFO group (D+IR+D) (n = 10); (5) Post-DFO group (IR+D) (n = 10); (6) For each DFO-treated group, the mice were intraperitoneally injected with 0.1 ml sterilized water alone (by which DFO was dissolved) for 3 days before and/or after irradiation, and served as control. Sham1: Pre-sterilized water group (n = 5); sham2: Pre+Post sterilized water group (n = 5); sham3: Post-sterilized water group (n = 5). The salivary flow rate (SFR) was assessed at 30th, 60th and 90th day after irradiation, respectively. After 90 days, all mice were sacrificed and their submandibular glands were removed for further examinations. RESULTS The salivary glands showed remarkable dysfunction and tissue damage after irradiation. DFO restored SFR in the irradiated glands to a level comparable to that in normal glands and angiogenesis in damaged tissue was greatly increased. DFO also increased the expression levels of HIF-1α and VEGF while reduced apoptotic cells. Furthermore, Sca-1+cells were preserved in the salivary glands treated with DFO before IR. CONCLUSIONS Our results indicate DFO could prevent the radiation-induced dysfunction of salivary glands in mice. The mechanism of this protective effect may involve increased angiogenesis, reduced apoptosis of acinar cells and more preserved stem cells.
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Synergistic effects of dimethyloxalylglycine and butyrate incorporated into α-calcium sulfate on bone regeneration. Biomaterials 2014; 39:1-14. [PMID: 25477166 DOI: 10.1016/j.biomaterials.2014.10.054] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/19/2014] [Indexed: 01/22/2023]
Abstract
Osteogenesis is closely related to angiogenesis, and the combined delivery of angiogenic and osteogenic factors has been suggested to enhance bone regeneration. Small molecules have been explored as alternatives to growth factors for tissue regeneration applications. In this study, we examined the effects of the combined application of angiogenic and osteogenic small molecules on bone regeneration using a prolyl hydroxylase, dimethyloxalylglycine (DMOG), and a histone deacetylase inhibitor, butyrate. In a critical size bone defect model in rats, DMOG and butyrate, which were incorporated into α calcium sulfate (αCS), resulted in synergistic enhancements in bone and blood vessel formation, eventually leading to bone healing, as confirmed by micro-CT and histological analyses. In MC4 pre-osteoblast cultures, DMOG and butyrate enhanced the pro-angiogenic responses and osteoblast differentiation, respectively, which were evaluated based on the levels of hypoxia inducible factor (HIF)-1α protein and the expression of pro-angiogenic molecules (VEGF, home oxidase-1, glucose transporter-1) and by alkaline phosphatase (ALP) activity and the expression of osteoblast phenotype marker molecules (ALP, α1(I)col, osteocalcin, and bone sialoprotein). DMOG combined with butyrate synergistically improved osteoblast differentiation and pro-angiogenic responses, the levels of which were drastically increased in the cultures on αCS disks. Furthermore, it was demonstrated that αCS increased the level of HIF-1α and as a consequence VEGF expression, and supported osteoblast differentiation through the release of calcium ions from the αCS. Altogether, the results of this study provide evidence that a combination treatment with the small molecules DMOG and butyrate can expedite the process of bone regeneration and that αCS can be an efficient delivery vehicle for the small molecules for bone regeneration.
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Peng J, Lai ZG, Fang ZL, Xing S, Hui K, Hao C, Jin Q, Qi Z, Shen WJ, Dong QN, Bing ZH, Fu DL. Dimethyloxalylglycine prevents bone loss in ovariectomized C57BL/6J mice through enhanced angiogenesis and osteogenesis. PLoS One 2014; 9:e112744. [PMID: 25394221 PMCID: PMC4231053 DOI: 10.1371/journal.pone.0112744] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/12/2014] [Indexed: 12/16/2022] Open
Abstract
Hypoxia-inducible factor 1-α (HIF-1α) plays a critical role in angiogenesis-osteogenesis coupling during bone development and bone regeneration. Previous studies have shown that 17β-estradiol activates the HIF-1α signaling pathway and that mice with conditional activation of the HIF-1α signaling pathway in osteoblasts are protected from ovariectomy (OVX)-induced bone loss. In addition, it has been shown that hypoxia facilitates the osteogenic differentiation of mesenchymal stem cells (MSCs) and modulates Wnt/β-catenin signaling. Therefore, we hypothesized that activation of the HIF-1α signaling pathway by hypoxia-mimicking agents would prevent bone loss due to estrogen deficiency. In this study, we confirmed the effect of dimethyloxalylglycine (DMOG), a hypoxia-mimicking agent, on the HIF-1α signaling pathway and investigated the effect of DMOG on MSC osteogenic differentiation and the Wnt/β-catenin signaling pathway. We then investigated the effect of DMOG treatment on OVX-induced bone loss. Female C57BL/6J mice were divided into sham, OVX, OVX+L-DMOG (5 mg/kg/day), and OVX+H-DMOG (20 mg/kg/day) groups. At sacrifice, static and dynamic bone histomorphometry were performed with micro computed tomography (micro-CT) and undecalcified sections, respectively. Bone strength was assessed with the three-point bending test, and femur vessels were reconstructed and analyzed by micro-CT. Serum vascular endothelial growth factor (VEGF), osteocalcin, and C-terminal telopeptides of collagen type(CTX) were measured by ELISA. Tartrate-resistant acid phosphatase staining was used to assess osteoclast formation. Alterations in the HIF-1α and Wnt/β-catenin signaling pathways in the bone were detected by western blot. Our results showed that DMOG activated the HIF-1α signaling pathway, which further activated the Wnt/β-catenin signaling pathway and enhanced MSC osteogenic differentiation. The micro-CT results showed that DMOG treatment improved trabecular bone density and restored the bone microarchitecture and blood vessels in OVX mice. Bone strength was also partly restored in DMOG-treated OVX mice. Dynamic bone histomorphometric analysis of the femur metaphysic revealed that DMOG increased the mineralizing surface, mineral apposition rate, and bone formation rate. The serum levels of VEGF and osteocalcin were higher in DMOG-treated OVX mice. However, there were no significant differences in serum CTX or in the number of tartrate-resistant acid phosphatase-stained cells between DMOG-treated OVX mice and OVX mice. Western blot results showed that DMOG administration partly rescued the decrease in HIF-1α and β-catenin expression following ovariectomy. Collectively, these results indicate that DMOG prevents bone loss due to ovariectomy in C57BL/6J mice by enhancing angiogenesis and osteogenesis, which are associated with activated HIF-1α and Wnt/β-catenin signaling pathways.
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Affiliation(s)
- Jia Peng
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Zuo Gui Lai
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
- Department of Orthopaedics, Qian Fo Shan Hospital, Shang Dong University, Ji Nan, China
| | - Zhang Lian Fang
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Shen Xing
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Kang Hui
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Hao
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Qi Jin
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Zhou Qi
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Wang Jin Shen
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Qian Nian Dong
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Zhou Han Bing
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Deng Lian Fu
- Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China
- * E-mail:
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Sham A, Martinez EC, Beyer S, Trau DW, Raghunath M. Incorporation of a prolyl hydroxylase inhibitor into scaffolds: a strategy for stimulating vascularization. Tissue Eng Part A 2014; 21:1106-15. [PMID: 25370818 DOI: 10.1089/ten.tea.2014.0077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Clinical applications of tissue engineering are constrained by the ability of the implanted construct to invoke vascularization in adequate extent and velocity. To overcome the current limitations presented by local delivery of single angiogenic factors, we explored the incorporation of prolyl hydroxylase inhibitors (PHIs) into scaffolds as an alternative vascularization strategy. PHIs are small molecule drugs that can stabilize the alpha subunit of hypoxia-inducible factor-1 (HIF-1), a key transcription factor that regulates a variety of angiogenic mechanisms. In this study, we conjugated the PHI pyridine-2,4-dicarboxylic acid (PDCA) through amide bonds to a gelatin sponge (Gelfoam(®)). Fibroblasts cultured on PDCA-Gelfoam were able to infiltrate and proliferate in these scaffolds while secreting significantly more vascular endothelial growth factor than cells grown on Gelfoam without PDCA. Reporter cells expressing green fluorescent protein-tagged HIF-1α exhibited dose-dependent stabilization of this angiogenic transcription factor when growing within PDCA-Gelfoam constructs. Subsequently, we implanted PDCA-Gelfoam scaffolds into the perirenal fat tissue of Sprague Dawley rats for 8 days. Immunostaining of explants revealed that the PDCA-Gelfoam scaffolds were amply infiltrated by cells and promoted vascular ingrowth in a dose-dependent manner. Thus, the incorporation of PHIs into scaffolds appears to be a feasible strategy for improving vascularization in regenerative medicine applications.
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Affiliation(s)
- Adeline Sham
- 1 Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
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The prolyl hydroxylase inhibitor dimethyloxalylglycine enhances dentin sialophoshoprotein expression through VEGF-induced Runx2 stabilization. PLoS One 2014; 9:e112078. [PMID: 25369078 PMCID: PMC4219688 DOI: 10.1371/journal.pone.0112078] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/13/2014] [Indexed: 01/19/2023] Open
Abstract
Prolyl hydroxylase (PHD) inhibitors are suggested as therapeutic agents for tissue regeneration based on their ability to induce pro-angiogenic responses. In this study, we examined the effect of the PHD inhibitor dimethyloxalylglycine (DMOG) on odontoblast maturation and sought to determine the underlying mechanism using MDPC-23 odontoblast-like cells. DMOG significantly enhanced matrix mineralization, confirmed by alizarin red staining and by measurement of the calcium content. DMOG dose-dependently increased alkaline phosphatase activity and the expressions of dentin sialophosphoprotein (Dspp) and osteocalcin. To determine the underlying events leading to DMOG-induced Dspp expression, we analyzed the effect of DMOG on Runx2. Knockdown of Runx2 using siRNAs decreased Dspp expression and prevented DMOG-induced Dspp expression. DMOG enhanced the transcriptional activity and level of Runx2 protein but not Runx2 transcript, and this enhancement was linked to the inhibitory effects of DMOG on the degradation of Runx2 protein. The vascular endothelial growth factor (VEGF) siRNAs profoundly decreased the Runx2 protein levels and inhibited the DMOG-increased Runx2 protein. Recombinant VEGF protein treatment significantly and dose-dependently increased the transcriptional activity and level of the Runx2 protein but not Runx2 transcript. Dspp expression was also enhanced by VEGF. Last, we examined the involvement of the Erk mitogen-activated protein kinase and Pin1 pathway in VEGF-enhanced Runx2 because this pathway can regulate the stability and activity of the Runx2 protein. VEGF stimulated Erk activation, and the inhibitors of Erk and Pin1 hampered VEGF-enhanced Runx2 protein. Taken together, the results of this study provide evidence that DMOG can enhance Dspp expression through VEGF-induced stabilization of Runx2 protein, and thus, suggest that DMOG can be used as a therapeutic tool for enhancing odontoblast maturation in dental procedures.
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111
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Hamid O, Pensch M, Agis H. Release kinetics of prolyl hydroxylase inhibitors from collagen barrier membranes. J Biomater Appl 2014; 29:1059-67. [PMID: 25326176 DOI: 10.1177/0885328214556158] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Collagen barrier membranes are used in guided tissue regeneration to support healing. This strategy, however, relies on the healing capacity of the tissue. Pharmacological inhibitors of prolyl hydroxylases can support regeneration by enhancing angiogenesis and are therefore a promising tool for periodontology. Here we evaluate the release kinetics of the prolyl hydroxylase inhibitors dimethyloxalylglycine and L-mimosine from collagen barrier membranes. Dimethyloxalylglycine and L-mimosine were lyophilized onto the collagen barrier membranes. The morphology of the collagen barrier membranes was analysed using scanning electron microscopy. The release of prolyl hydroxylase inhibitors was assessed by colorimetric and spectroscopic methods. Their ability to induce a cellular response was assessed in bioassays with gingival and periodontal ligament fibroblasts based on vascular endothelial growth factor production, proliferation, and metabolic activity of the cells. We found that loading of collagen barrier membranes with prolyl hydroxylase inhibitors did not change the overall membrane morphology. Assessment of the release kinetics by direct measurements and based on vascular endothelial growth factor production showed that supernatants obtained from the collagen barrier membranes in the first 6 hours had a sufficient level of prolyl hydroxylase inhibitors to induce vascular endothelial growth factor production. A similar kinetic was found when cell proliferation was assessed. Changes in metabolic activity did not reach the level of significance in the MTT assay. In conclusion, collagen barrier membranes can release prolyl hydroxylase inhibitors thereby increasing the pro-angiogenic capacity of periodontal cells in vitro. These findings provide the basis for preclinical studies to evaluate the regenerative capacity of prolyl hydroxylase inhibitors in periodontology and oral surgery.
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Affiliation(s)
- Omar Hamid
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria Department of Conservative Dentistry and Periodontology, Medical University of Vienna, Vienna, Austria
| | - Manuela Pensch
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria Department of Conservative Dentistry and Periodontology, Medical University of Vienna, Vienna, Austria
| | - Hermann Agis
- Department of Conservative Dentistry and Periodontology, Medical University of Vienna, Vienna, Austria Austrian Cluster for Tissue Regeneration, Vienna, Austria
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112
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Vinzenz P, Schröckmair S, Gruber R, Agis H. Bone substitute materials supplemented with prolyl hydroxylase inhibitors decrease osteoclastogenesis in vitro. J Biomed Mater Res B Appl Biomater 2014; 103:1198-203. [PMID: 25312707 DOI: 10.1002/jbm.b.33295] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 08/14/2014] [Accepted: 09/12/2014] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVE Inhibition of prolyl hydroxylases stimulates bone regeneration. Consequently, bone substitute materials were developed that release prolyl hydroxylase inhibitors. However, the impact of prolyl hydroxylase inhibitors released from these carriers on osteoclastogenesis is not clear. We therefore assessed the effect of bone substitute materials that release prolyl hydroxylase inhibitors on osteoclastogenesis. MATERIAL AND METHODS Dimethyloxalylglycine, desferrioxamine, and l-mimosine were lyophilized onto bovine bone mineral and hydroxyapatite, and supernatants were generated. Osteoclastogenesis was induced in murine bone marrow cultures in the presence of the supernatants from bone substitute materials. The formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and TRAP activity were determined. To test for possible effects on osteoclast progenitor cells, we measured the effect of the supernatants on proliferation and viability. In addition, experiments were performed where prolyl hydroxylase inhibitors were directly added to the bone marrow cultures. RESULTS We found that prolyl hydroxylase inhibitors released within the first hours from bone substitute materials reduce the number and activity of TRAP-positive multinucleated cells. In line with this, addition of prolyl hydroxylase inhibitors directly to the bone marrow cultures dose-dependently reduced the number of TRAP-positive multinucleated cells and the overall resorption activity. Moreover, the released prolyl hydroxylase inhibitors decreased proliferation but not viability of osteoclast progenitor cells. CONCLUSION Our results show that prolyl hydroxylase inhibitors released from bone substitute materials decrease osteoclastogenesis in murine bone marrow cultures.
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Affiliation(s)
- Philipp Vinzenz
- Department of Oral Surgery, Medical University of Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Stefan Schröckmair
- Department of Oral Surgery, Medical University of Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Reinhard Gruber
- Department of Oral Surgery, Medical University of Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria.,Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Hermann Agis
- Austrian Cluster for Tissue Regeneration, Vienna, Austria.,Department of Conservative Dentistry and Periodontology, Medical University of Vienna, Vienna, Austria
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113
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Li J, Fan L, Yu Z, Dang X, Wang K. The effect of deferoxamine on angiogenesis and bone repair in steroid-induced osteonecrosis of rabbit femoral heads. Exp Biol Med (Maywood) 2014; 240:273-80. [PMID: 25294892 DOI: 10.1177/1535370214553906] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In this study, we examined whether local deferoxamine (DFO) administration can promote angiogenesis and bone repair in steroid-induced osteonecrosis of the femoral head (ONFH). Steroid-induced ONFH was induced in 65 mature male New Zealand white rabbits by methylprednisolone in combination with lipopolysaccharide. Six weeks later, the rabbits received no treatment (model group, N = 15), bilateral core decompression (CD group, N = 20) or CD in combination with local DFO administration (DFO group, N = 20). Six weeks after the surgery, vascularization in the femoral head was evaluated by ink artery infusion angiography and immunohistochemical staining for von Willebrand Factor (vWF). Bone repair was assessed by histologic analysis and micro-computed tomography (micro-CT). Immunohistochemical staining was performed to analyze the expression of vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1α (HIF-1α), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OCN). Ink artery infusion angiography and microvessel analysis by immuohistochemical staining for vWF showed more blood vessels in the DFO group than other groups. The expression of HIF-1α, VEGF, BMP-2, and OCN, indicated by immunohistochemical staining, was higher in the DFO group compared with other groups. Micro-CT scanning results indicated that the DFO group had larger volume of newly formed bone than the CD group. This work indicated that local DFO administration improved angiogenesis and bone repair of early stage ONFH in rabbit model, and it may offer an efficient, economic, and simple therapy for early stage ONFH.
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Affiliation(s)
- Jia Li
- The First Department of Orthopedics, The Second Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xiwu Road, Xi'an, Shaanxi Province 710004, China
| | - Lihong Fan
- The First Department of Orthopedics, The Second Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xiwu Road, Xi'an, Shaanxi Province 710004, China
| | - Zefeng Yu
- The First Department of Orthopedics, The Second Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xiwu Road, Xi'an, Shaanxi Province 710004, China
| | - Xiaoqian Dang
- The First Department of Orthopedics, The Second Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xiwu Road, Xi'an, Shaanxi Province 710004, China
| | - Kunzheng Wang
- The First Department of Orthopedics, The Second Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xiwu Road, Xi'an, Shaanxi Province 710004, China
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Agis H, Hueber L, Pour Sadeghian N, Pensch M, Gruber R. In vitro release of dimethyloxaloylglycine and l-mimosine from bovine bone mineral. Arch Oral Biol 2014; 59:1024-31. [DOI: 10.1016/j.archoralbio.2014.05.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/28/2014] [Indexed: 12/12/2022]
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Fan L, Li J, Yu Z, Dang X, Wang K. Hypoxia-inducible factor prolyl hydroxylase inhibitor prevents steroid-associated osteonecrosis of the femoral head in rabbits by promoting angiogenesis and inhibiting apoptosis. PLoS One 2014; 9:e107774. [PMID: 25244080 PMCID: PMC4171501 DOI: 10.1371/journal.pone.0107774] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 08/14/2014] [Indexed: 12/31/2022] Open
Abstract
The purpose of this study was to investigate the preventive effect of ethyl 3,4-dihydroxybenzoate(EDHB) on steroid-associated femoral head osteonecrosis(ONFH) in a rabbit model. New Zealand white rabbits were randomly divided into two groups (prevention group and model group), each containing 24 rabbits. Osteonecrosis was induced by lipopolysaccharide(LPS) combined with methylprednisolone(MPS). The prevention group received an intraperitoneal injection of EDHB at 50 mg/kg body weight every other day starting three days before establishing rabbit models of osteonecrosis, for a total of nine doses. Osteonecrosis was verified by haematoxylin-eosin (HE) staining. The expression of HIF-1α and VEGF was analyzed by immunohistochemistry. Angiogenesis, apoptosis and microstructural parameters were also analyzed. The rabbit models of osteonecrosis were successfully established and observed by HE staining. Histopathological observations indicated that EDHB reduced the rate of empty lacunae and the incidence of osteonecrosis. Immunohistochemical staining for HIF-1α and VEGF suggested that EDHB therapy inhibited degradation of HIF-1α and promoted expression of VEGF. Ink artery infusion angiography and microvessel density analysis revealed that there were more microvessels in the prevention group than in the model group. The TUNEL apoptosis assay suggested that EDHB intervention could reduce the number of apoptotic cells in avascular osteonecrosis of the femoral head. Micro-CT scanning indicated that the treatment group had better microstructural parameters than the model group. EDHB prevents steroid-associated osteonecrosis of the femoral head in rabbits by promoting angiogenesis and inhibiting apoptosis of bone cells and hematopoietic tissue.
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Affiliation(s)
- Lihong Fan
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jia Li
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Zefeng Yu
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaoqian Dang
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Kunzheng Wang
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
- * E-mail:
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Kuchler U, Keibl C, Fügl A, Schwarze UY, Tangl S, Agis H, Gruber R. Dimethyloxalylglycine lyophilized onto bone substitutes increase vessel area in rat calvarial defects. Clin Oral Implants Res 2014; 26:485-91. [DOI: 10.1111/clr.12474] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Ulrike Kuchler
- Department of Oral Surgery; Medical University of Vienna; Vienna Austria
- Department of Oral Surgery and Stomatology; University of Berne; Berne Switzerland
| | - Claudia Keibl
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology; Vienna Austria
| | - Alexander Fügl
- Department of Oral Surgery; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
| | - Uwe Y. Schwarze
- Department of Oral Surgery; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Karl Donath Laboratory for Hard Tissue and Biomaterial Research; Department of Oral Surgery; Medical University of Vienna; Vienna Austria
| | - Stefan Tangl
- Department of Oral Surgery; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Karl Donath Laboratory for Hard Tissue and Biomaterial Research; Department of Oral Surgery; Medical University of Vienna; Vienna Austria
| | - Hermann Agis
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Department of Conservative Dentistry and Periodontology; Medical University of Vienna; Vienna Austria
| | - Reinhard Gruber
- Department of Oral Surgery; Medical University of Vienna; Vienna Austria
- Department of Oral Surgery and Stomatology; University of Berne; Berne Switzerland
- Laboratory of Oral Cell Biology; School of Dental Medicine; University of Berne; Berne Switzerland
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Donneys A, Nelson NS, Page EE, Deshpande SS, Felice PA, Tchanque-Fossuo CN, Spiegel JP, Buchman SR. Targeting angiogenesis as a therapeutic means to reinforce osteocyte survival and prevent nonunions in the aftermath of radiotherapy. Head Neck 2014; 37:1261-7. [PMID: 24801669 DOI: 10.1002/hed.23744] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/19/2014] [Accepted: 05/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Radiotherapy (XRT) exerts detrimental collateral effects on bone tissue through mechanisms of vascular damage and impediments to osteocytes, ultimately predisposing patients to the debilitating problems of late pathologic fractures and nonunions. We posit that angiogenic therapy will reverse these pathologic effects in a rat model of radiated fracture healing. METHODS Three groups of rats underwent mandibular osteotomy. Radiated groups received a fractionated 35-Gy dose before surgery. The deferoxamine (DFO) group received local injections postoperatively. A 40-day healing period was allowed before histology. Analysis of variance (ANOVA; p < .05) was used for group comparisons. RESULTS Radiated fractures revealed a significantly decreased osteocyte count and corresponding increase in empty lacunae when compared to nonradiated fractures (p = .001). With the addition of DFO, these differences were not appreciated. Further, a 42% increase in bony unions was observed after DFO therapy. CONCLUSION Targeting angiogenesis is a useful means for promoting osteocyte survival and preventing bone pathology after XRT.
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Affiliation(s)
- Alexis Donneys
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
| | - Noah S Nelson
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
| | - Erin E Page
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
| | - Sagar S Deshpande
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
| | - Peter A Felice
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan.,Department of General Surgery, University of South Carolina School of Medicine, Columbia, South Carolina
| | | | - Joshua P Spiegel
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
| | - Steven R Buchman
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan
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Trimmel K, Cvikl B, Müller HD, Nürnberger S, Gruber R, Moritz A, Agis H. L-mimosine increases the production of vascular endothelial growth factor in human tooth slice organ culture model. Int Endod J 2014; 48:252-60. [PMID: 24786562 DOI: 10.1111/iej.12307] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/26/2014] [Indexed: 12/26/2022]
Abstract
AIM To assess the pro-angiogenic and pro-inflammatory capacity of the dentine-pulp complex in response to the prolyl hydroxylase inhibitor L-mimosine in a tooth slice organ culture model. METHODOLOGY Human teeth were sectioned transversely into 600-μm-thick slices and cultured in medium supplemented with serum and antibiotics. Then, pulps were stimulated for 48 h with L-mimosine. Pulps were subjected to viability measurements based on formazan formation in MTT assays. In addition, histological evaluation of pulps was performed based on haematoxylin and eosin staining. Culture supernatants were subjected to immunoassays for vascular endothelial growth factor (VEGF) to determine the pro-angiogenic capacity and to immunoassays for interleukin (IL)-6 and IL-8 to assess the pro-inflammatory response. Interleukin-1 served as pro-inflammatory control. Echinomycin was used to inhibit hypoxia-inducible factor-1 (HIF-1) alpha activity. Data were analysed using Student's t-test and Mann-Whitney U test. RESULTS Pulps within tooth slices remained vital upon L-mimosine stimulation as indicated by formazan formation and histological evaluation. L-mimosine increased VEGF production when normalized to formazan formation in the pulp tissue of the tooth slices (P < 0.05). This effect on VEGF was reduced by echinomycin (P < 0.01). Changes in normalized IL-6 and IL-8 levels upon treatment with L-mimosine did not reach the level of significance (P > 0.05), whilst treatment with IL-1, which served as positive control, increased IL-6 (P < 0.05) and IL-8 levels (P < 0.05). CONCLUSIONS The prolyl hydroxylase inhibitor L-mimosine increased VEGF production via HIF-1 alpha in the tooth slice organ culture model whilst inducing no prominent increase in IL-6 and IL-8. Pre-clinical studies will reveal if these in vitro effects translate into dental pulp regeneration.
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Affiliation(s)
- K Trimmel
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
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Lim SH, Kim C, Aref AR, Kamm RD, Raghunath M. Complementary effects of ciclopirox olamine, a prolyl hydroxylase inhibitor and sphingosine 1-phosphate on fibroblasts and endothelial cells in driving capillary sprouting. Integr Biol (Camb) 2014; 5:1474-84. [PMID: 24190477 DOI: 10.1039/c3ib40082d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Capillary sprouting, a key step of neoangiogenesis in wound healing and tumor growth, also represents a therapeutic target for tissue repair. It requires crosstalk between endothelial cells (EC) and other cell types. We studied this process in a microfluidic platform that allows EC to migrate out of a channel across a collagen gel up a gradient of factors produced by a collection of encapsulated fibroblasts. Introduction of a prolyl hydroxylase inhibitor (PHi), ciclopirox olamine (CPX) to stabilize hypoxia inducible factor 1α (HIF-1α) predominantly in fibroblasts induced capillary sprouting in EC, but the most complex tubular networks with true lumina formed after combining CPX with the lysophospholipid sphingosine 1-phosphate (S1P). The enhanced angiogenesis is a possible consequence of the generation of mutually stimulating factors as each cell type responded differently to the compounds. The combination of CPX and S1P induced secretion of vascular endothelial growth factor (VEGF) in fibroblast culture whereas the angiogenic monocyte chemoattractant protein (MCP)-1 was exclusively secreted by fibroblasts, but only in the presence of EC-conditioned medium. Antibody interference with fibroblast-produced VEGF and MCP-1 inhibited the sprouting response. These observations not only demonstrate the collaboration of EC and fibroblasts in inducing capillary sprouting but also suggest that the combination of CPX and S1P enhances angiogenesis and thus might be of therapeutic value for the pharmacological induction of tissue repair and regeneration.
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Affiliation(s)
- Sei Hien Lim
- Biosystems & Micromechanics Interdisciplinary Research Group (BioSyM), Singapore-MIT Alliance in Research & Technology (SMART), Singapore
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Selvaraju V, Parinandi NL, Adluri RS, Goldman JW, Hussain N, Sanchez JA, Maulik N. Molecular mechanisms of action and therapeutic uses of pharmacological inhibitors of HIF-prolyl 4-hydroxylases for treatment of ischemic diseases. Antioxid Redox Signal 2014; 20:2631-65. [PMID: 23992027 PMCID: PMC4026215 DOI: 10.1089/ars.2013.5186] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 08/06/2013] [Accepted: 09/01/2013] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE In this review, we have discussed the efficacy and effect of small molecules that act as prolyl hydroxylase domain inhibitors (PHDIs). The use of these compounds causes upregulation of the pro-angiogenic factors and hypoxia inducible factor-1α and -2α (HIF-1α and HIF-2α) to enhance angiogenic, glycolytic, erythropoietic, and anti-apoptotic pathways in the treatment of various ischemic diseases responsible for significant morbidity and mortality in humans. RECENT ADVANCES Sprouting of new blood vessels from the existing vasculature and surgical intervention, such as coronary bypass and stent insertion, have been shown to be effective in attenuating ischemia. However, the initial reentry of oxygen leads to the formation of reactive oxygen species that cause oxidative stress and result in ischemia/reperfusion (IR) injury. This apparent "oxygen paradox" must be resolved to combat IR injury. During hypoxia, decreased activity of PHDs initiates the accumulation and activation of HIF-1α, wherein the modulation of both PHD and HIF-1α appears as promising therapeutic targets for the pharmacological treatment of ischemic diseases. CRITICAL ISSUES Research on PHDs and HIFs has shown that these molecules can serve as therapeutic targets for ischemic diseases by modulating glycolysis, erythropoiesis, apoptosis, and angiogenesis. Efforts are underway to identify and synthesize safer small-molecule inhibitors of PHDs that can be administered in vivo as therapy against ischemic diseases. FUTURE DIRECTIONS This review presents a comprehensive and current account of the existing small-molecule PHDIs and their use in the treatment of ischemic diseases with a focus on the molecular mechanisms of therapeutic action in animal models.
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Affiliation(s)
- Vaithinathan Selvaraju
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Narasimham L. Parinandi
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio
| | - Ram Sudheer Adluri
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Joshua W. Goldman
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Naveed Hussain
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut
- Division of Neonatal Medicine, Connecticut Children's Medical Center, Hartford, Connecticut
| | - Juan A. Sanchez
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Nilanjana Maulik
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
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The hypoxia-inducible factor pathway, prolyl hydroxylase domain protein inhibitors, and their roles in bone repair and regeneration. BIOMED RESEARCH INTERNATIONAL 2014; 2014:239356. [PMID: 24895555 PMCID: PMC4034436 DOI: 10.1155/2014/239356] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/23/2014] [Accepted: 02/16/2014] [Indexed: 02/06/2023]
Abstract
Hypoxia-inducible factors (HIFs) are oxygen-dependent transcriptional activators that play crucial roles in angiogenesis, erythropoiesis, energy metabolism, and cell fate decisions. The group of enzymes that can catalyse the hydroxylation reaction of HIF-1 is prolyl hydroxylase domain proteins (PHDs). PHD inhibitors (PHIs) activate the HIF pathway by preventing degradation of HIF-α via inhibiting PHDs. Osteogenesis and angiogenesis are tightly coupled during bone repair and regeneration. Numerous studies suggest that HIFs and their target gene, vascular endothelial growth factor (VEGF), are critical regulators of angiogenic-osteogenic coupling. In this brief perspective, we review current studies about the HIF pathway and its role in bone repair and regeneration, as well as the cellular and molecular mechanisms involved. Additionally, we briefly discuss the therapeutic manipulation of HIFs and VEGF in bone repair and bone tumours. This review will expand our knowledge of biology of HIFs, PHDs, PHD inhibitors, and bone regeneration, and it may also aid the design of novel therapies for accelerating bone repair and regeneration or inhibiting bone tumours.
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Abstract
BACKGROUND Distraction osteogenesis is a powerful reconstructive technique for bone growth and repair. An angiogenic means of enhancing the efficacy of this metabolically demanding procedure would be beneficial in expanding its therapeutic potential. The authors posit that the angiogenic effect of deferoxamine, an iron chelator that has been shown to increase angiogenesis, will improve bone regeneration by means of augmentations in quality and quantity of bone and bone-producing cells. METHODS Two groups of rats (n = 12) underwent surgical external fixation and subsequent distraction. During the distraction stage, the experimental deferoxamine group (n = 5) was treated with injections into the distraction gap. After 28 days of consolidation, mandibles were harvested and prepared for histologic analysis. RESULTS The authors found a proliferation of osteocytes in the deferoxamine-treated group when compared with the regenerate of the control group. Deferoxamine effected a significant increase in osteocytes and an increase in bone volume fraction, with subsequent decreased osteoid volume fraction. The data also demonstrated no significant difference in empty lacunae. CONCLUSIONS The authors' study demonstrates the effectiveness of deferoxamine treatment to enhance the number of osteocytes within the regenerate in a murine mandibular distraction osteogenesis model. Maintenance of full lacunae supports the authors' finding of a robust cellular response to deferoxamine therapy. These results suggest that the angiogenic capabilities of deferoxamine translate into an increase in the number of bone-forming cells in the regenerate. Deferoxamine may have utility in optimizing bone formation in distraction osteogenesis and lead to superior reconstructive capabilities for craniofacial surgeons in the future.
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Jiang L, Peng WW, Li LF, Du R, Wu TT, Zhou ZJ, Zhao JJ, Yang Y, Qu DL, Zhu YQ. Effects of deferoxamine on the repair ability of dental pulp cells in vitro. J Endod 2014; 40:1100-4. [PMID: 25069915 DOI: 10.1016/j.joen.2013.12.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/25/2013] [Accepted: 12/06/2013] [Indexed: 01/07/2023]
Abstract
INTRODUCTION In previous studies, we found that hypoxia promoted the mineralization of dental pulp cells (DPCs). However, the clinical application of hypoxia as a therapy is questionable or unfeasible. Deferoxamine (DFO), a medication for iron overload, has also been shown to induce hypoxia. The purpose of this study was to investigate the effects of DFO on the repair ability of DPCs. METHODS DPCs were obtained by using a tissue explant technique in vitro and were treated with different concentrations of DFO or hypoxia culture for 2 days. The viability, proliferation, migration, and odontogenic differentiation of DPCs were assayed and analyzed. The expression of hypoxia-inducible factor 1-alpha (HIF-1α) was assessed through Western blotting. RESULTS Ten micromolars of DFO enhanced the expression of HIF-1α similarly to hypoxia and did not affect the viability of DPCs for 2 days. Furthermore, the proliferation, migration, and odontogenic differentiation of DPCs were promoted by DFO. CONCLUSIONS These results suggest that DFO might improve the repair ability of DPCs by HIF-1α.
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Affiliation(s)
- Long Jiang
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Wei-Wei Peng
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Li-Fen Li
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Rong Du
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Tian-Tian Wu
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Zhuo-Jun Zhou
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Jun-Jun Zhao
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Ya Yang
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Dong-Lin Qu
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Ya-Qin Zhu
- Department of General Dentistry, 9th People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
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Nelson CE, Kim AJ, Adolph EJ, Gupta MK, Yu F, Hocking KM, Davidson JM, Guelcher SA, Duvall CL. Tunable delivery of siRNA from a biodegradable scaffold to promote angiogenesis in vivo. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:607-14, 506. [PMID: 24338842 PMCID: PMC3951880 DOI: 10.1002/adma.201303520] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/14/2013] [Indexed: 05/17/2023]
Abstract
A system has been engineered for temporally controlled delivery of siRNA from biodegradable tissue regenerative scaffolds. Therapeutic application of this approach to silence prolyl hydroxylase domain 2 promoted expression of pro-angiogenic genes controlled by HIF1α and enhanced scaffold vascularization in vivo. This technology provides a new standard for efficient and controllable gene silencing to modulate host response within regenerative biomaterials.
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Affiliation(s)
- Christopher E. Nelson
- Biomedical Engineering – Vanderbilt University, VU Station B, Box 351631, Nashville TN 37235
| | - Arnold J. Kim
- Biomedical Engineering – Vanderbilt University, VU Station B, Box 351631, Nashville TN 37235
| | - Elizabeth J. Adolph
- Chemical and Biomolecular Engineering – Vanderbilt University, Nashville TN 37235
| | - Mukesh K. Gupta
- Biomedical Engineering – Vanderbilt University, VU Station B, Box 351631, Nashville TN 37235
| | - Fang Yu
- Department of Pathology – Vanderbilt University, Nashville TN 37235
| | - Kyle M. Hocking
- Biomedical Engineering – Vanderbilt University, VU Station B, Box 351631, Nashville TN 37235
| | | | - Scott A. Guelcher
- Chemical and Biomolecular Engineering – Vanderbilt University, Nashville TN 37235
| | - Craig L. Duvall
- Biomedical Engineering – Vanderbilt University, VU Station B, Box 351631, Nashville TN 37235
- Prof. C.L. Duvall, Vanderbilt University, VU Station B, Box 351631, Nashville, TN, 37235, USA,
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Grewal BS, Keller B, Weinhold P, Dahners LE. Evaluating effects of deferoxamine in a rat tibia critical bone defect model. J Orthop 2013; 11:5-9. [PMID: 24719526 DOI: 10.1016/j.jor.2013.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/07/2013] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Evaluate the use of deferoxamine in a calcium sulfate carrier to promote fracture healing in a critical bone defect model. METHODS 43 female retired breeders were divided randomly into Control, Carrier, DFO and BMP groups and appropriate agents placed at the osteotomy site. RESULTS There was a significant difference in the mean gap between groups Control vs DFO and Control vs BMP. A higher mean number of cortices were bridged in the DFO group as compared to the Control group. CONCLUSIONS Our study demonstrated that DFO helped reduce the gap in this critical tibia defect.
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Affiliation(s)
- Bikramjit S Grewal
- Department of Orthopaedics, University of North Carolina Hospitals, NC 27514, USA
| | - Benjamin Keller
- Joint Department of Biomedical Engineering, University of North Carolina, NC 27599, USA
| | - Paul Weinhold
- Department of Orthopaedics, University of North Carolina Hospitals, NC 27514, USA ; Joint Department of Biomedical Engineering, University of North Carolina, NC 27599, USA
| | - Laurence E Dahners
- Department of Orthopaedics, University of North Carolina Hospitals, NC 27514, USA
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Felice PA, Ahsan S, Donneys A, Deshpande SS, Nelson NS, Buchman SR. Deferoxamine administration delivers translational optimization of distraction osteogenesis in the irradiated mandible. Plast Reconstr Surg 2013; 132:542e-548e. [PMID: 24076701 DOI: 10.1097/prs.0b013e31829fe548] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND The authors' laboratory has previously demonstrated that deferoxamine promotes angiogenesis and bone repair in the setting of radiation therapy coupled with distraction osteogenesis. However, clinically relevant effects of deferoxamine administration on union rate and micro-computed tomographic and biomechanical parameters are unknown. The authors posit that administration of deferoxamine will increase union rate, mineralization, and strength of the regenerate in an irradiated distraction osteogenesis model. METHODS Sprague-Dawley rats were randomized into three groups: distraction osteogenesis-control, distraction osteogenesis-radiation therapy, and distraction osteogenesis-radiation therapy-deferoxamine. All animals underwent an osteotomy and distraction osteogenesis across a 5.1-mm distraction gap. Irradiated animals received 35-Gy human-equivalent radiation therapy 2 weeks before surgery, and deferoxamine was injected postoperatively in the regenerate site of treatment animals. Animals were killed on postoperative day 40, and mandibles were harvested to determine rates of bony union and micro-computed tomographic and biomechanical parameters. RESULTS Compared with irradiated mandibles, deferoxamine-treated mandibles exhibited a higher union rate (11 percent versus 92 percent, respectively). Across micro-computed tomographic and biomechanical parameters, significant diminutions were observed with administration of radiation therapy, whereas deferoxamine therapy resulted in significant restoration to levels of controls, with select metrics exhibiting significant increases even beyond controls. CONCLUSIONS The authors' data confirm that deferoxamine restores clinically relevant metrics of bony union and micro-computed tomographic and biomechanical parameters in a model of irradiated distraction osteogenesis in the murine mandible. Their findings support a potential use for deferoxamine in treatment protocols to allow predictable and reliable use of distraction osteogenesis as a viable reconstructive option in patients with head and neck cancer.
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Affiliation(s)
- Peter A Felice
- Ann Arbor, Mich.; and Columbia, S.C. From the Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan; and the Department of Surgery, University of South Carolina School of Medicine
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127
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Weidemann A, Breyer J, Rehm M, Eckardt KU, Daniel C, Cicha I, Giehl K, Goppelt-Struebe M. HIF-1α activation results in actin cytoskeleton reorganization and modulation of Rac-1 signaling in endothelial cells. Cell Commun Signal 2013; 11:80. [PMID: 24144209 PMCID: PMC3895861 DOI: 10.1186/1478-811x-11-80] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/10/2013] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Hypoxia is a major driving force in vascularization and vascular remodeling. Pharmacological inhibition of prolyl hydroxylases (PHDs) leads to an oxygen-independent and long-lasting activation of hypoxia-inducible factors (HIFs). Whereas effects of HIF-stabilization on transcriptional responses have been thoroughly investigated in endothelial cells, the molecular details of cytoskeletal changes elicited by PHD-inhibition remain largely unknown. To investigate this important aspect of PHD-inhibition, we used a spheroid-on-matrix cell culture model. RESULTS Microvascular endothelial cells (glEND.2) were organized into spheroids. Migration of cells from the spheroids was quantified and analyzed by immunocytochemistry. The PHD inhibitor dimethyloxalyl glycine (DMOG) induced F-actin stress fiber formation in migrating cells, but only weakly affected microvascular endothelial cells firmly attached in a monolayer. Compared to control spheroids, the residual spheroids were larger upon PHD inhibition and contained more cells with tight VE-cadherin positive cell-cell contacts. Morphological alterations were dependent on stabilization of HIF-1α and not HIF-2α as shown in cells with stable knockdown of HIF-α isoforms. DMOG-treated endothelial cells exhibited a reduction of immunoreactive Rac-1 at the migrating front, concomitant with a diminished Rac-1 activity, whereas total Rac-1 protein remained unchanged. Two chemically distinct Rac-1 inhibitors mimicked the effects of DMOG in terms of F-actin fiber formation and orientation, as well as stabilization of residual spheroids. Furthermore, phosphorylation of p21-activated kinase PAK downstream of Rac-1 was reduced by DMOG in a HIF-1α-dependent manner. Stabilization of cell-cell contacts associated with decreased Rac-1 activity was also confirmed in human umbilical vein endothelial cells. CONCLUSIONS Our data demonstrates that PHD inhibition induces HIF-1α-dependent cytoskeletal remodeling in endothelial cells, which is mediated essentially by a reduction in Rac-1 signaling.
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Affiliation(s)
| | | | | | | | | | | | | | - Margarete Goppelt-Struebe
- Department of Nephrology and Hypertension, Universitätsklinikum Erlangen, Universität Erlangen-Nürnberg, Loschgestrasse 8, 91054 Erlangen, Germany.
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128
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Chung JH, Kim YS, Noh K, Lee YM, Chang SW, Kim EC. Deferoxamine promotes osteoblastic differentiation in human periodontal ligament cells via the nuclear factor erythroid 2-related factor-mediated antioxidant signaling pathway. J Periodontal Res 2013; 49:563-73. [PMID: 24111577 DOI: 10.1111/jre.12136] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Recently it was reported that deferoxamine (DFO), an iron chelator, stimulates bone formation from MG63 and mesenchymal stem cells, but inhibits differentiation in rat calvarial cells; however, the effect of DFO on osteoblastic differentiation in human periodontal ligament cells (hPDLCs) has not been reported. The aim of this study was to investigate the effects and the possible underlying mechanism of DFO on osteoblastic differentiation of hPDLCs. MATERIAL AND METHODS The effect of DFO on osteoblast differentiation was determined by the staining intensity of calcium deposits with Alizarin red and by RT-PCR analysis of the expression of osteoblastic markers. Signal transduction pathways were analyzed by western blotting. RESULTS DFO increased osteogenic differentiation in a concentration-dependent manner by expression of the mRNA for differentiation markers and calcium nodule formation. Exposure of hPDLCs to DFO resulted in increases in the production of reactive oxygen species and in the levels of nuclear factor erythroid 2-related factor (Nrf2) protein in nuclear extractions, as well as a dose-dependent increase in the expression of Nrf2 target genes, including glutathione (GSH), glutathione S-transferase, γ-glutamylcysteine lygase, glutathione reductase and glutathione peroxidase. Pretreatment with Nrf2 small interfering RNA, GSH depletion by buthionine sulfoximine and diethyl maleate, and with antioxidants by N-acetylcysteine and vitamin E, blocked DFO-stimulated osteoblastic differentiation. Furthermore, pretreatment with GSH depletion and antioxidants blocked DFO-induced p38 MAPK, ERK, JNK and nuclear factor-kappaB pathways. CONCLUSION These data indicate, for the first time, that nontoxic DFO promotes osteoblastic differentiation of hPDLCs via modulation of the Nrf2-mediated antioxidant pathway.
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Affiliation(s)
- J H Chung
- Department of Periodontology, School of Dentistry, Kyung Hee University, Seoul, Korea
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129
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Taniguchi CM, Finger EC, Krieg AJ, Wu C, Diep AN, LaGory EL, Wei K, McGinnis LM, Yuan J, Kuo CJ, Giaccia AJ. Cross-talk between hypoxia and insulin signaling through Phd3 regulates hepatic glucose and lipid metabolism and ameliorates diabetes. Nat Med 2013; 19:1325-30. [PMID: 24037093 DOI: 10.1038/nm.3294] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/09/2013] [Indexed: 02/07/2023]
Abstract
Signaling initiated by hypoxia and insulin powerfully alters cellular metabolism. The protein stability of hypoxia-inducible factor-1 alpha (Hif-1α) and Hif-2α is regulated by three prolyl hydroxylase domain-containing protein isoforms (Phd1, Phd2 and Phd3). Insulin receptor substrate-2 (Irs2) is a critical mediator of the anabolic effects of insulin, and its decreased expression contributes to the pathophysiology of insulin resistance and diabetes. Although Hif regulates many metabolic pathways, it is unknown whether the Phd proteins regulate glucose and lipid metabolism in the liver. Here, we show that acute deletion of hepatic Phd3, also known as Egln3, improves insulin sensitivity and ameliorates diabetes by specifically stabilizing Hif-2α, which then increases Irs2 transcription and insulin-stimulated Akt activation. Hif-2α and Irs2 are both necessary for the improved insulin sensitivity, as knockdown of either molecule abrogates the beneficial effects of Phd3 knockout on glucose tolerance and insulin-stimulated Akt phosphorylation. Augmenting levels of Hif-2α through various combinations of Phd gene knockouts did not further improve hepatic metabolism and only added toxicity. Thus, isoform-specific inhibition of Phd3 could be exploited to treat type 2 diabetes without the toxicity that could occur with chronic inhibition of multiple Phd isoforms.
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Affiliation(s)
- Cullen M Taniguchi
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Center for Clinical Sciences Research, Stanford, California, USA
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130
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Roche B, Vanden-Bossche A, Normand M, Malaval L, Vico L, Lafage-Proust MH. Validated Laser Doppler protocol for measurement of mouse bone blood perfusion - response to age or ovariectomy differs with genetic background. Bone 2013; 55:418-26. [PMID: 23571049 DOI: 10.1016/j.bone.2013.03.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/15/2013] [Accepted: 03/30/2013] [Indexed: 12/29/2022]
Abstract
The physiological role of bone vascularization in bone metabolism begins to be understood; however, its involvement in pathological situations remains poorly explored. Bone blood supply depends on both vascular density and blood flow. However, in mice, the specific evaluation of perfusion in bone suffers from a lack of easy-handling measurement tools. In the present study, we first developed a Laser Doppler Perfusion Measurement (LDPM) protocol in mouse tibia, which we validated with ex vivo and in vivo experiments. Then we carried out a study associating both structural (vascular quantitative histomorphometry) and functional (LDPM) approaches. We studied the effects of aging in 4, 7 and 17 month-old male mice and the early effects of ovariectomy in 4 month-old females. Both studies were carried out in inbred mice (C57BL/6) and in mice of mixed background (129sv/CD1). The significant differences we observed between strains in unchallenged 4 month-old animals concerned both perfusion and vascular density and depended on gender. Additionally, the age-related bone loss observed in male mice was not temporally associated with vascular changes in either strain. Between 7 and 17 months, we did not find any decrease in bone vascular density or perfusion. In contrast, ovariectomy triggered early vascular structural and functional adaptations which differed between genetic backgrounds. We observed that bone vessel density did not generally account for bone perfusion levels. In conclusion, we describe here a LDPM-based experimental protocol which provides a reproducible quantitative evaluation of bone perfusion in mouse tibia, hence allowing intergroup comparisons. This integrative structural and functional approach of bone vascularization showed that bone vascular adaptation occurs during aging or after ovariectomy and is affected by the genetic background.
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Affiliation(s)
- Bernard Roche
- INSERM U1059, Université de Lyon, Saint-Etienne F-42023, France.
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131
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Donneys A, Deshpande SS, Tchanque-Fossuo CN, Johnson KL, Blough JT, Perosky JE, Kozloff KM, Felice PA, Nelson NS, Farberg AS, Levi B, Buchman SR. Deferoxamine expedites consolidation during mandibular distraction osteogenesis. Bone 2013; 55:384-90. [PMID: 23598047 PMCID: PMC4162399 DOI: 10.1016/j.bone.2013.04.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 03/29/2013] [Accepted: 04/07/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND A limitation of mandibular distraction osteogenesis (DO) is the length of time required for consolidation. This drawback subjects patients to possible pin-site infections, as well as a prolonged return to activities of normal daily living. Developing innovative techniques to abridge consolidation periods could be immensely effective in preventing these problematic morbidities. Deferoxamine (DFO) is an angiogenic activator that triggers the HIF-1α pathway through localized iron depletion. We previously established the effectiveness of DFO in enhancing regenerate vascularity at a full consolidation period (28 days) in a murine mandibular DO model. To investigate whether this augmentation in vascularity would function to accelerate consolidation, we progressively shortened consolidation periods prior to μCT imaging and biomechanical testing (BMT). MATERIALS AND METHODS Three time points (14d, 21d and 28d) were selected and six groups of Sprague-Dawley rats (n = 60) were equally divided into control (C) and experimental (E) groups for each time period. Each group underwent external fixator placement, mandibular osteotomy, and a 5.1 mm distraction. During distraction, the experimental groups were treated with DFO injections into the regenerate gap. After consolidation, mandibles were imaged and tension tested to failure. ANOVA was conducted between groups, and p < 0.05 was considered statistically significant. RESULTS At 14 days of consolidation the experimental group demonstrated significant increases in bone volume fraction (BVF), bone mineral density (BMD) and ultimate load (UL) in comparison to non-treated controls. The benefit of treatment was further substantiated by a striking 100% increase in the number of bony unions at this early time-period (C:4/10 vs. E:8/10). Furthermore, metrics of BVF, BMD, Yield and UL at 14 days with treatment demonstrated comparable metrics to those of the fully consolidated 28d control group. CONCLUSION Based on these findings, we contend that augmentation of vascular density through localized DFO injection delivers an efficient means for accelerating bone regeneration without significantly impacting bone quality or strength.
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Affiliation(s)
- Alexis Donneys
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Sagar S. Deshpande
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Kelsey L. Johnson
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Jordan T. Blough
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph E. Perosky
- Orthopedic Research Laboratory, Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Kenneth M. Kozloff
- Orthopedic Research Laboratory, Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter A. Felice
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Noah S. Nelson
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Aaron S. Farberg
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin Levi
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
| | - Steven R. Buchman
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan, Ann Arbor, Michigan, USA
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132
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Liu GS, Peshavariya HM, Higuchi M, Chan EC, Dusting GJ, Jiang F. Pharmacological priming of adipose-derived stem cells for paracrine VEGF production with deferoxamine. J Tissue Eng Regen Med 2013; 10:E167-76. [DOI: 10.1002/term.1796] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 02/08/2013] [Accepted: 06/12/2013] [Indexed: 12/23/2022]
Affiliation(s)
- Guei-Sheung Liu
- O'Brien Institute; Fitzroy Victoria Australia
- Centre for Eye Research Australia and Department of Ophthalmology; University of Melbourne; East Melbourne Victoria Australia
| | - Hitesh M. Peshavariya
- O'Brien Institute; Fitzroy Victoria Australia
- Centre for Eye Research Australia and Department of Ophthalmology; University of Melbourne; East Melbourne Victoria Australia
| | | | - Elsa C. Chan
- O'Brien Institute; Fitzroy Victoria Australia
- Centre for Eye Research Australia and Department of Ophthalmology; University of Melbourne; East Melbourne Victoria Australia
| | - Gregory J. Dusting
- O'Brien Institute; Fitzroy Victoria Australia
- Centre for Eye Research Australia and Department of Ophthalmology; University of Melbourne; East Melbourne Victoria Australia
| | - Fan Jiang
- O'Brien Institute; Fitzroy Victoria Australia
- Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital; Shandong University; Jinan Shandong Province China
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133
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Deferoxamine restores callus size, mineralization, and mechanical strength in fracture healing after radiotherapy. Plast Reconstr Surg 2013; 131:711e-719e. [PMID: 23629110 DOI: 10.1097/prs.0b013e3182865c57] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Therapeutic augmentation of fracture-site angiogenesis with deferoxamine has proven to increase vascularity, callus size, and mineralization in long-bone fracture models. The authors posit that the addition of deferoxamine would enhance pathologic fracture healing in the setting of radiotherapy in a model where nonunions are the most common outcome. METHODS Thirty-five Sprague-Dawley rats were divided into three groups. Fracture, irradiated fracture, and irradiated fracture plus deferoxamine. The irradiated fracture and irradiated fracture plus deferoxamine groups received a human equivalent dose of radiotherapy [7 Gy/day for 5 days, (35 Gy)] 2 weeks before mandibular osteotomy and external fixation. The irradiated fracture plus deferoxamine group received injections of deferoxamine into the fracture callus after surgery. After a 40-day healing period, mandibles were dissected, clinically assessed for bony union, imaged with micro-computed tomography, and tension tested to failure. RESULTS Compared with irradiated fractures, metrics of callus size, mineralization, and strength in deferoxamine-treated mandibles were significantly increased. These metrics were restored to a level demonstrating no statistical difference from control fractures. In addition, the authors observed an increased rate of achieving bony unions in the irradiated fracture plus deferoxamine-treated group when compared with irradiated fracture (67 percent and 20 percent, respectively). CONCLUSIONS The authors' data demonstrate nearly total restoration of callus size, mineralization, and biomechanical strength, and a threefold increase in the rate of union with the use of deferoxamine. The authors' results suggest that the administration of deferoxamine may have the potential for clinical translation as a new treatment paradigm for radiation-induced pathologic fractures.
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134
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Wehner C, Gruber R, Agis H. L-mimosine and dimethyloxaloylglycine decrease plasminogen activation in periodontal fibroblasts. J Periodontol 2013; 85:627-35. [PMID: 23826644 DOI: 10.1902/jop.2013.120703] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The use of prolyl hydroxylase inhibitors such as l-mimosine (L-MIM) and dimethyloxaloylglycine (DMOG) to improve angiogenesis is a new approach for periodontal regeneration. In addition to exhibiting pro-angiogenic effects, prolyl hydroxylase inhibitors can modulate the plasminogen activator system in cells from non-oral tissues. This study assesses the effect of prolyl hydroxylase inhibitors on plasminogen activation by fibroblasts from the periodontium. METHODS Gingival and periodontal ligament fibroblasts were incubated with L-MIM and DMOG. To investigate whether prolyl hydroxylase inhibitors modulate the net plasminogen activation, kinetic assays were performed with and without interleukin (IL)-1. Moreover, plasminogen activators and the respective inhibitors were analyzed by casein zymography, immune assays, and quantitative polymerase chain reaction. RESULTS The kinetic assay showed that L-MIM and DMOG reduced plasminogen activation under basal and IL-1-stimulated conditions. Casein zymography revealed that the effect of L-MIM involves a decrease in urokinase-type plasminogen activator activity. In agreement with these findings, reduced levels of urokinase-type plasminogen activator and elevated levels of plasminogen activator inhibitor 1 were observed. CONCLUSION L-MIM and DMOG can reduce plasminogen activation by fibroblasts from the gingiva and the periodontal ligament under basal conditions and in the presence of an inflammatory cytokine.
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Affiliation(s)
- Christian Wehner
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria
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135
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Najafi R, Sharifi AM. Deferoxamine preconditioning potentiates mesenchymal stem cell homing in vitro and in streptozotocin-diabetic rats. Expert Opin Biol Ther 2013; 13:959-72. [PMID: 23536977 DOI: 10.1517/14712598.2013.782390] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Today, cell therapy is considered a promising alternative in treatment of several diseases such as type 1 diabetes. Loss of transplanted stem cell and more importantly scarcity in the number of cells reaching to target tissue is a major obstacle in cell therapy. There is evidences showing that deferoxamine (DFO), an iron chelator, increases the mobilization and homing of progenitor cells through increasing the stability of hypoxia-inducible factor 1α (HIF-1α) protein. In this study, the effect of DFO on some factors involved in homing of bone marrow-derived mesenchymal stem cell was investigated, and the other objectives of this research were to determine whether DFO is able to increase migration and subsequent homing of mesenchymal stem cell (MSCs) both in vitro and in vivo in streptozotocin-diabetic rats. RESEARCH DESIGN AND METHODS MSCs were treated by DFO in minimal essential medium α (αMEM) for 24 h. The expression and localization of HIF-1α were evaluated by western blotting and immunocytochemistry. The expression of C-X-C chemokine receptor type 4 (CXCR-4) and chemokine receptor 2 (CCR2) were assessed by western blotting and RT-PCR. The activity of matrix metalloproteinases (MMP) -2 and -9 were measured by gelatin zymography. Finally, in vitro migration of MSCs toward different concentrations of stromal cell-derived factor and monocyte chemotactic protein-1 were also evaluated. To demonstrate the homing of MSCs in vivo, DFO-treated chloromethyl-benzamidodialkylcarbocyanine-labeled MSCs were injected into the tail vein of rats, and the number of stained MSCs reaching to the pancreas were determined after 24 h. RESULTS In DFO-treated MSCs, expression of HIF-1α (p < 0.001), CXCR4 (p < 0.001), CCR2 (p < 0.001), and the activity of MMP-2 (p < 0.01) and MMP-9 (p < 0.05) were significantly increased compared to control groups. Elevation of HIF-1α, upregulation of CXCR4/CCR2 and higher activity of MMP-2/MMP-9 in DFO-treated MSCs were reversed by 2-methoxyestradiol (2-ME; 5 μmol), a HIF-1α inhibitor. The in vitro migrations as well as in vivo homing of DFO-treated MSCs were also significantly higher than control groups (p < 0.05). CONCLUSIONS Preconditioning of MSCs by DFO prior to transplantation could increase homing of MSCs through affecting some chemokine receptors as well as proteases involved and eventually improving the efficacy of cell therapy.
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Affiliation(s)
- R Najafi
- Tehran University of Medical Sciences, School of Medicine, Razi Drug Research Center, Department of Pharmacology, Tehran, Iran
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136
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Donneys A, Weiss DM, Deshpande SS, Ahsan S, Tchanque-Fossuo CN, Sarhaddi D, Levi B, Goldstein SA, Buchman SR. Localized deferoxamine injection augments vascularity and improves bony union in pathologic fracture healing after radiotherapy. Bone 2013; 52:318-25. [PMID: 23085084 PMCID: PMC3513581 DOI: 10.1016/j.bone.2012.10.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/11/2012] [Accepted: 10/12/2012] [Indexed: 11/24/2022]
Abstract
BACKGROUND Medically based efforts and alternative treatment strategies to prevent or remediate the corrosive effects of radiotherapy on pathologic fracture healing have failed to produce clear and convincing evidence of success. Establishing an effective pharmacologic option to prevent or treat the development of non-unions in this setting could have immense therapeutic potential. Experimental studies have shown that deferoxamine (DFO), an iron-chelating agent, bolsters vascularity and subsequently enhances normal fracture healing when injected locally into a fracture callus in long bone animal models. Since radiotherapy is known to impede angiogenesis, we hypothesized that the pharmacologic addition of DFO would serve to mitigate the effects of radiotherapy on new vessel formation in vitro and in vivo. MATERIALS AND METHODS In vitro investigation of angiogenesis was conducted utilizing HUVEC cells in Matrigel. Endothelial tubule formation assays were divided into four groups: Control, Radiated, Radiated+Low-Dose DFO and Radiated+High-Dose DFO. Tubule formation was quantified microscopically and video recorded for the four groups simultaneously during the experiment. In vivo, three groups of Sprague-Dawley rats underwent external fixator placement and fracture osteotomy of the left mandible. Two groups received pre-operative fractionated radiotherapy, and one of these groups was treated with DFO after fracture repair. After 40 days, the animals were perfused and imaged with micro-CT to calculate vascular radiomorphometrics. RESULTS In vitro, endothelial tubule formation assays demonstrated that DFO mitigated the deleterious effects of radiation on angiogenesis. Further, high-dose DFO cultures appeared to organize within 2h of incubation and achieved a robust network that was visibly superior to all other experimental groups in an accelerated fashion. In vivo, animals subjected to a human equivalent dose of radiotherapy (HEDR) and left mandibular fracture demonstrated quantifiably diminished μCT metrics of vascular density, as well as a 75% incidence of associated non-unions. The addition of DFO in this setting markedly improved vascularity as demonstrated with 3D angiographic modeling. In addition, we observed an increased incidence of bony unions in the DFO treated group when compared to radiated fractures without treatment (67% vs. 25% respectively). CONCLUSION Our data suggest that selectively targeting angiogenesis with localized DFO injections is sufficient to remediate the associated severe vascular diminution resulting from a HEDR. Perhaps the most consequential and clinically relevant finding was the ability to reduce the incidence of non-unions in a model where fracture healing was not routinely observed.
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Affiliation(s)
- Alexis Donneys
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniela M. Weiss
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Sagar S. Deshpande
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Salman Ahsan
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Catherine N. Tchanque-Fossuo
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Deniz Sarhaddi
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin Levi
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Steven A. Goldstein
- Orthopedic Research Laboratory, Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Steven R. Buchman
- Craniofacial Research Laboratory, Department of Plastic Surgery, University of Michigan, Ann Arbor, Michigan, USA
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137
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Lu C, Saless N, Wang X, Sinha A, Decker S, Kazakia G, Hou H, Williams B, Swartz HM, Hunt TK, Miclau T, Marcucio RS. The role of oxygen during fracture healing. Bone 2013; 52:220-9. [PMID: 23063782 PMCID: PMC4827706 DOI: 10.1016/j.bone.2012.09.037] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/20/2012] [Accepted: 09/21/2012] [Indexed: 10/27/2022]
Abstract
Oxygen affects the activity of multiple skeletogenic cells and is involved in many processes that are important for fracture healing. However, the role of oxygen in fracture healing has not been fully studied. Here we systematically examine the effects of oxygen tension on fracture healing and test the ability of hyperoxia to rescue healing defects in a mouse model of ischemic fracture healing. Mice with tibia fracture were housed in custom-built gas chambers and groups breathed a constant atmosphere of 13% oxygen (hypoxia), 21% oxygen (normoxia), or 50% oxygen (hyperoxia). The influx of inflammatory cells to the fracture site, stem cell differentiation, tissue vascularization, and fracture healing were analyzed. In addition, the efficacy of hyperoxia (50% oxygen) as a treatment regimen for fracture nonunion was tested. Hypoxic animals had decreased tissue vascularity, decreased bone formation, and delayed callus remodeling. Hyperoxia increased tissue vascularization, altered fracture healing in un-complicated fractures, and improved bone repair in ischemia-induced delayed fracture union. However, neither hypoxia nor hyperoxia significantly altered chondrogenesis or osteogenesis during early stages of fracture healing, and infiltration of macrophages and neutrophils was not affected by environmental oxygen after bone injury. In conclusion, our results indicate that environmental oxygen levels affect tissue vascularization and fracture healing, and that providing oxygen when fractures are accompanied by ischemia may be beneficial.
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Affiliation(s)
- Chuanyong Lu
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
- Currently at: Department of Pathology, SUNY Downstate Medical Center, Brooklyn, NY
| | - Neema Saless
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Xiaodong Wang
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Arjun Sinha
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Sebastian Decker
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Galateia Kazakia
- Department of Radiology, University of California at San Francisco
| | - Huagang Hou
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Benjamin Williams
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Harold M. Swartz
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH
| | - Thomas K. Hunt
- Department of Surgery, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Theodore Miclau
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
| | - Ralph S. Marcucio
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, 1001 Potrero Ave., San Francisco, CA94110
- Author for correspondence: Phone: 415-206-5366, Fax: 415-647-3733,
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Müller HD, Cvikl B, Gruber R, Watzek G, Agis H. Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor in dental pulp-derived cells. J Endod 2012; 38:1498-503. [PMID: 23063224 DOI: 10.1016/j.joen.2012.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 07/29/2012] [Accepted: 08/02/2012] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Prolyl hydroxylase (PHD) inhibitors can induce a proangiogenic response that stimulates regeneration in soft and hard tissues. However, the effect of PHD inhibitors on the dental pulp is unclear. The purpose of this study was to evaluate the effects of PHD inhibitors on the proangiogenic capacity of human dental pulp-derived cells. METHODS To test the response of dental pulp-derived cells to PHD inhibitors, the cells were exposed to dimethyloxalylglycine, desferrioxamine, L-mimosine, and cobalt chloride. To assess the response of dental pulp cells to a capping material supplemented with PHD inhibitors, the cells were treated with supernatants from calcium hydroxide. Viability, proliferation, and protein synthesis were assessed by formazan formation, (3)[H]thymidine, and (3)[H]leucine incorporation assays. The effect on the proangiogenic capacity was measured by immunoassays for vascular endothelial growth factor (VEGF). RESULTS We found that all 4 PHD inhibitors can reduce viability, proliferation, and protein synthesis at high concentrations. At nontoxic concentrations and in the presence of supernatants from calcium hydroxide, PHD inhibitors stimulated the production of VEGF in dental pulp-derived cells. When calcium hydroxide was supplemented with the PHD inhibitors, the supernatants from these preparations did not significantly elevate VEGF levels. CONCLUSIONS These results show that PHD inhibitors can stimulate VEGF production of dental pulp-derived cells, suggesting a corresponding increase in their proangiogenic capacity. Further studies will be required to understand the impact that this might have on pulp regeneration.
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Morgan EF, Hussein AI, Al-Awadhi BA, Hogan DE, Matsubara H, Al-Alq Z, Fitch J, Andre B, Hosur K, Gerstenfeld LC. Vascular development during distraction osteogenesis proceeds by sequential intramuscular arteriogenesis followed by intraosteal angiogenesis. Bone 2012; 51:535-45. [PMID: 22617817 PMCID: PMC3412922 DOI: 10.1016/j.bone.2012.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 05/11/2012] [Accepted: 05/13/2012] [Indexed: 11/23/2022]
Abstract
Vascular formation is intimately associated with bone formation during distraction osteogenesis (DO). While prior studies on this association have focused on vascular formation locally within the regenerate, we hypothesized that this vascular formation, as well as the resulting osteogenesis, relies heavily on the response of the vascular network in surrounding muscular compartments. To test this hypothesis, the spatiotemporal sequence of vascular formation was assessed in both muscular and osseous compartments in a murine model of DO and was compared to the progression of osteogenesis. Micro-computed tomography (μCT) scans were performed sequentially, before and after demineralization, on specimens containing contrast-enhanced vascular casts. Image registration and subtraction procedures were developed to examine the co-related, spatiotemporal patterns of vascular and osseous tissue formation. Immunohistochemistry was used to assess the contributory roles of arteriogenesis (formation of large vessels) and angiogenesis (formation of small vessels) to overall vessel formation. Mean vessel thickness showed an increasing trend during the period of active distraction (p=0.068), whereas vessel volume showed maximal increases during the consolidation period (p=0.009). The volume of mineralized tissue in the regenerate increased over time (p<0.039), was correlated with vessel volume (r=0.59; p=0.025), and occurred primarily during consolidation. Immunohistological data suggested that: 1) the period of active distraction was characterized primarily by arteriogenesis in the surrounding muscle; 2) during consolidation, angiogenesis predominated in the intraosteal region; and 3) vessel formation proceeded from the surrounding muscle into the regenerate. These data show that formation of vascular tissue occurs in both muscular and osseous compartments during DO and that periods of intense osteogenesis are concurrent with those of angiogenesis. The results further suggest the presence of morphogenetic factors that coordinate the development of vascular tissues from the intramuscular compartment into the regions of osseous regeneration.
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Affiliation(s)
- Elise F Morgan
- Orthopaedic and Developmental Biomechanics Laboratory, Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA.
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Abstract
Bone never forms without vascular interactions. This simple statement of fact does not adequately reflect the physiological and pharmacological implications of the relationship. The vasculature is the conduit for nutrient exchange between bone and the rest of the body. The vasculature provides the sustentacular niche for development of osteoblast progenitors and is the conduit for egress of bone marrow cell products arising, in turn, from the osteoblast-dependent haematopoietic niche. Importantly, the second most calcified structure in humans after the skeleton is the vasculature. Once considered a passive process of dead and dying cells, vascular calcification has emerged as an actively regulated form of tissue biomineralization. Skeletal morphogens and osteochondrogenic transcription factors are expressed by cells within the vessel wall, which regulates the deposition of vascular calcium. Osteotropic hormones, including parathyroid hormone, regulate both vascular and skeletal mineralization. Cellular, endocrine and metabolic signals that flow bidirectionally between the vasculature and bone are necessary for both bone health and vascular health. Dysmetabolic states including diabetes mellitus, uraemia and hyperlipidaemia perturb the bone-vascular axis, giving rise to devastating vascular and skeletal disease. A detailed understanding of bone-vascular interactions is necessary to address the unmet clinical needs of an increasingly aged and dysmetabolic population.
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Affiliation(s)
- Bithika Thompson
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, Campus Box 8127, 660 South Euclid Avenue, St Louis, MO 63110, USA
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Hastings CL, Kelly HM, Murphy MJ, Barry FP, O'Brien FJ, Duffy GP. Development of a thermoresponsive chitosan gel combined with human mesenchymal stem cells and desferrioxamine as a multimodal pro-angiogenic therapeutic for the treatment of critical limb ischaemia. J Control Release 2012; 161:73-80. [DOI: 10.1016/j.jconrel.2012.04.033] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 04/16/2012] [Accepted: 04/20/2012] [Indexed: 12/01/2022]
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Deferoxamine enhances the vascular response of bone regeneration in mandibular distraction osteogenesis. Plast Reconstr Surg 2012; 129:850-856. [PMID: 22456357 DOI: 10.1097/prs.0b013e31824422f2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Bone regeneration during distraction osteogenesis is intricately associated with an enhanced vascular response. Augmenting this response may offer considerable clinical advantages such as optimizing the quality of regenerate formation, decreasing lengthy consolidation periods, or increasing regenerate size and distance. Using deferoxamine, an angiogenic transcriptional activator, the authors posit that substantial increases in vascular volume beyond the normal response to mechanical distraction can be quantified with micro-computed tomography after vessel perfusion during mandibular distraction osteogenesis. METHODS Two groups of Sprague-Dawley rats (n = 12) underwent external fixator placement, mandibular osteotomy, and 5.1-mm distraction. During distraction, the experimental group (n = 6) was treated with deferoxamine injections into the distraction gap. After consolidation, the animals were perfused and imaged with micro-computed tomography. Vascular radiomorphometrics were calculated and statistical comparison was conducted with the independent samples t test. A value of p ≤ 0.05 was considered statistically significant. RESULTS A 40 percent statistically significant increase in the number of vessels (0.82 vessels/mm versus 1.15 vessels/mm; p < 0.012) and a complementary decrease in the space between vessels (1.18 mm versus 0.86 mm; p < 0.012) were calculated in the experimental regenerate when compared with controls. This robust increase in vascularity could also be readily observed with micro-computed tomographic image reconstruction. Gross examination revealed a denser regenerate in the deferoxamine-injected group that is clearly illustrated with Faxitron radiography. CONCLUSION The authors' study quantifies the ability of deferoxamine to augment the vascular response of mandibular distraction osteogenesis and establishes correlations between this therapeutic enrichment and enhanced regenerate formation.
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143
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Zhang W, Li G, Deng R, Deng L, Qiu S. New bone formation in a true bone ceramic scaffold loaded with desferrioxamine in the treatment of segmental bone defect: a preliminary study. J Orthop Sci 2012; 17:289-98. [PMID: 22526711 DOI: 10.1007/s00776-012-0206-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 02/21/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Desferrioxamine (DFO), an iron chelator, can stimulate osteogenesis and angiogenesis by stabilizing hypoxia-inducible factor 1α. We postulate that a bone graft substitute combined with DFO is beneficial to the reconstruction of bone defects. METHODS We implanted pure true bone ceramic (TBC) and DFO-loaded TBC (DFO/TBC) scaffolds into 15-mm rabbit radial defects for 8 weeks. The bone segments were examined with X-ray, micro-CT and histology. RESULTS Radiographs showed that the DFO/TBC scaffold became radiopaque, and the gaps between the scaffold and radial cut ends were often invisible. Variables from micro-CT, including the bone volume fraction (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), were significantly increased in pure TBC and DFO/TBC scaffolds that had been implanted for 8 weeks compared to unimplanted TBC scaffolds (p values <0.05-0.001). Between the former two groups, BV/TV and Tb.Th were significantly increased in DFO/TBC scaffolds (p < 0.001), but Tb.N did not show significant differences. Histological examinations showed considerably increased new bone and decreased TBC trabecular remnants in DFO/TBC scaffolds compared to pure TBC scaffolds. Many cavities in the new bone area in DFO/TBC scaffolds were occupied by bone marrow elements and blood vessels. Percent of new bone with tetracycline labeling was significantly greater in DFO/TBC scaffolds than in pure TBC scaffolds (p < 0.001). CONCLUSION This preliminary study reveals that DFO can effectively induce new bone growing into TBC scaffolds, suggesting that the DFO/TBC composite is a promising bone graft substitute for the treatment of bone defects.
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Affiliation(s)
- Weibin Zhang
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, People's Republic of China
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Farberg AS, Jing XL, Monson LA, Donneys A, Tchanque-Fossuo CN, Deshpande SS, Buchman SR. Deferoxamine reverses radiation induced hypovascularity during bone regeneration and repair in the murine mandible. Bone 2012; 50:1184-7. [PMID: 22314387 PMCID: PMC3322244 DOI: 10.1016/j.bone.2012.01.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 02/05/2023]
Abstract
BACKGROUND Deferoxamine (DFO) is an iron-chelating agent that has also been shown to increase angiogenesis. We hypothesize that the angiogenic properties of DFO will improve bone regeneration in distraction osteogenesis (DO) after x-ray radiation therapy (XRT) by restoring the vascularity around the distraction site. MATERIAL AND METHODS Three groups of Sprague-Dawley rats underwent distraction of the left mandible. Two groups received pre-operative fractionated XRT, and one of these groups was treated with DFO during distraction. After consolidation, the animals were perfused and imaged with micro-CT to calculate vascular radiomorphometrics. RESULTS Radiation inflicted a severe diminution in the vascular metrics of the distracted regenerate and consequently led to poor clinical outcome. The DFO treated group revealed improved DO bone regeneration with a substantial restoration and proliferation of vascularity. CONCLUSIONS This set of experiments quantitatively demonstrates the ability of DFO to temper the anti-angiogenic effect of XRT in mandibular DO. These exciting results suggest that DFO may be a viable treatment option aimed at mitigating the damaging effects of XRT on new bone formation.
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Affiliation(s)
- Aaron S. Farberg
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xi L. Jing
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Dept of Surgery, Henry Ford Health System, Detroit, Michigan, USA
| | - Laura A. Monson
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alexis Donneys
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Sagar S. Deshpande
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Steven R. Buchman
- Craniofacial Research Laboratory, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Abstract
Adaptation to hypoxia is a critical cellular event both in pathological settings, such as cancer and ischaemia, and in normal development and differentiation. Oxygen is thought to be not only an indispensable metabolic substrate for a variety of in vivo enzymatic reactions, including mitochondrial respiration, but also a key regulatory signal in tissue development and homeostasis by controlling a specific genetic program. Hypoxia-inducible transcription factors (HIFs) HIF-1 and HIF-2 are central mediators of the homeostatic response that enables cells to survive and differentiate in low-oxygen conditions. Genetically altered mice have been used to identify important roles for HIF-1 and HIF-2 as well as vascular endothelial growth factor (VEGF)-a potent angiogenic factor and a downstream target of the HIF pathway-in the regulation of skeletal development, bone homeostasis and haematopoiesis. In this Review, we summarize the current knowledge of HIF signalling in cartilage, bone and blood, and pay particular attention to the complex relationship between HIF and VEGF in these tissues revealed by data from research using animal models. The study of these models expands our understanding of the cell autonomous, paracrine and autocrine effects that mediate the homeostatic responses downstream of HIFs and VEGF.
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Donneys A, Tchanque-Fossuo CN, Farberg AS, Deshpande SS, Buchman SR. Bone regeneration in distraction osteogenesis demonstrates significantly increased vascularity in comparison to fracture repair in the mandible. J Craniofac Surg 2012; 23:328-32. [PMID: 22337436 PMCID: PMC3502076 DOI: 10.1097/scs.0b013e318241db26] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Tissue analysis of bone regenerate has suggested an intense vascular response after mandibular distraction osteogenesis (DO). Quantifying and three-dimensionally imaging this vascular response could be of immense clinical import in efforts to advance the utility of bone regeneration and repair. Conventional quantification of vascular responses has heretofore focused on inexact, cumbersome measurements of blood flow and histologic vessel counting. Using micro-computed tomography after vessel perfusion, we posit that quantitative vascular metrics will be significantly higher in mandibular DO compared with those observed in fracture repair (FxR) after bony union. METHODS Sprague-Dawley rats underwent mandibular osteotomy and external fixator placement. A DO group (n=9) underwent a 5.1-mm distraction, whereas a FxR group (n=12) had a 2.1-mm fixed gap set. Forty days after surgery, Microfil was perfused into the vasculature, and imaging ensued. Vascular radiomorphometrics were calculated for the regions of interest. Independent-samples t-test was performed for comparison, with statistical significance set at P≤0.05. RESULTS Stereological analysis demonstrated statistically significant increases in the distracted vasculature compared with fracture repair: vessel volume fraction (5.4% versus 2.8%, P=0.030) and vessel number (0.86 versus 0.50 mm, P=0.014). CONCLUSIONS We report robust and quantifiable increases in vascular density in DO compared with FxR. Our findings support a significant distinction between the regenerative processes of mandibular DO from the reparative mechanisms controlling fracture healing. A better understanding of the differences between the 2 types of bone formation may enable clinicians to selectively optimize therapeutic outcomes in the future.
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Affiliation(s)
- Alexis Donneys
- Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan Ann Arbor, Michigan 28109-4217, USA
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Agis H, Watzek G, Gruber R. Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor by periodontal fibroblasts. J Periodontal Res 2011; 47:165-73. [PMID: 21954882 DOI: 10.1111/j.1600-0765.2011.01415.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Pharmacological inhibitors of prolyl hydroxylases (PHDs) can induce a proangiogenic response that favors wound healing and bone regeneration. However, the response of periodontal cells to PHD inhibitors is unknown. MATERIAL AND METHODS To determine the effects of PHD inhibitors on periodontal cells, we exposed human fibroblasts from the gingiva and the periodontal ligament to dimethyloxallyl glycine, desferrioxamine, l-mimosine and CoCl(2). Viability, proliferation, and protein synthesis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), [(3)H]thymidine, and [(3)H]leucine incorporation, respectively. The levels of Ki67, hypoxia-inducible factor 1α (HIF-1α), p27, phosphorylated c-Jun N-terminal kinase (JNK) and phosphorylated p38 were determined by immunohistochemistry and western blotting. Vascular endothelial growth factor (VEGF) mRNA levels were measured by quantitative PCR. Protein levels of VEGF and interleukin (IL)-6 were evaluated by immunoassays. RESULTS We found that PHD inhibitors, while leaving cell viability unchanged, reduced proliferation and protein synthesis. This was paralleled by decreased Ki67 levels and increased p27 levels, suggesting that PHD inhibitors provoke growth arrest. Independently from this response, PHD inhibitors stabilized HIF-1α and increased the production of VEGF. This increase of VEGF was observed in the presence of proinflammatory IL-1 and pharmacological inhibitors of JNK and p38 signaling. Moreover, PHD inhibitors did not modulate expression of IL-6 and the phosphorylation of JNK and p38. CONCLUSION These results suggest that PHD inhibitors enhance the production of VEGF in periodontal fibroblasts, even in the presence of proinflammatory IL-1. The data further suggest that PHD inhibitors do not provoke a significant proinflammatory or anti-inflammatory response in this in vitro setting.
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Affiliation(s)
- H Agis
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria
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Abstract
BACKGROUND Segmental bone loss remains a challenging clinical problem. A frequent mitigating factor is inadequate blood supply. Small molecules that activate the hypoxia-inducible factor pathway can be used to stimulate angiogenesis. We investigated an approach to promote healing using angiogenic and osteogenic compounds in combination with a biodegradable, weightbearing scaffold. METHODS Adult rats underwent removal of a 5-mm segment of femur stabilized by a cylindrical biodegradable implant and intramedullary fixation. Treatment groups included 1) saline (negative control); 2) desferrioxamine (DFO, a hypoxia-inducible factor activator; 3) low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) (5 μg); 4) DFO and low-dose rhBMP-2 (5 μg); or 5) rh-BMP-2 (10 μg). Angiography was used to evaluate vascularity. Bone healing was assessed by radiographs, microcomputed tomography, histology, and biomechanical testing. RESULTS Increased vascularity was seen at 6 weeks in the DFO treatment group. There appeared to be increased bone bridging as assessed by radiographic scores and microcomputed tomography in the BMP groups, although the quantification of bone volume did not show statistically significant differences. Biomechanical testing revealed improved stiffness in the treatment groups. CONCLUSIONS DFO improved angiogenesis and stiffness of bone healing in segmental defects. BMP improved radiographic scores and stiffness. Use of angiogenic compounds in segmental bone loss is promising. CLINICAL RELEVANCE Activation of the hypoxia-inducible factor pathway may prove useful for bone defects, particularly where impaired blood supply exists.The low-cost approach could be useful in segmental bone defects clinically.
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Crowe B, Poynter JA, Manukyan MC, Wang Y, Brewster BD, Herrmann JL, Abarbanell AM, Weil BR, Meldrum DR. Pretreatment with intracoronary mimosine improves postischemic myocardial functional recovery. Surgery 2011; 150:191-6. [DOI: 10.1016/j.surg.2011.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 05/13/2011] [Indexed: 10/17/2022]
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Abstract
Hypoxic signaling plays an essential role in maintaining oxygen homeostasis and cell survival. Hypoxia-inducible transcription factors HIF-1 and HIF-2 are central mediators of the cellular response to hypoxia by regulating the expression of genes controlling metabolic adaptation, oxygen delivery, and survival in response to oxygen deprivation. Recent studies have identified an important role for HIF-1 and HIF-2 in the regulation of skeletal development, bone formation, and regeneration, as well as joint formation and homeostasis. In addition, overexpression of HIF-1 and HIF-2 is clinically associated with osteosarcoma and osteoarthritis. Together, these findings implicate hypoxic signaling as a central regulator of bone biology and disease.
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Affiliation(s)
- Erinn B. Rankin
- Endocrine Unit, Massachusetts General Hospital-Harvard Medical School, Boston, MA 02114, USA; Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA 94303–5152, USA
| | - Amato J. Giaccia
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA 94303–5152, USA
| | - Ernestina Schipani
- Endocrine Unit, Massachusetts General Hospital-Harvard Medical School, Boston, MA 02114, USA
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