RESUMEN
Mechanical stimuli including loading after birth promote bone growth. However, little is known about how mechanical force triggers biochemical signals to regulate bone growth. Here, we identified a periosteal-osteoblast-derived secretory peptide, Osteocrin (OSTN), as a mechanotransducer involved in load-induced long bone growth. OSTN produced by periosteal osteoblasts regulates growth plate growth by enhancing C-type natriuretic peptide (CNP)-dependent proliferation and maturation of chondrocytes, leading to elongation of long bones. Additionally, OSTN cooperates with CNP to regulate bone formation. CNP stimulates osteogenic differentiation of periosteal osteoprogenitors to induce bone formation. OSTN binds to natriuretic peptide receptor 3 (NPR3) in periosteal osteoprogenitors, thereby preventing NPR3-mediated clearance of CNP and consequently facilitating CNP-signal-mediated bone growth. Importantly, physiological loading induces Ostn expression in periosteal osteoblasts by suppressing Forkhead box protein O1 (FoxO1) transcription factor. Thus, this study reveals a crucial role of OSTN as a mechanotransducer converting mechanical loading to CNP-dependent bone formation.
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Desarrollo Óseo , Proteínas Musculares/metabolismo , Periostio/crecimiento & desarrollo , Periostio/metabolismo , Estrés Mecánico , Factores de Transcripción/metabolismo , Animales , Diferenciación Celular , Ratones Noqueados , Péptido Natriurético Tipo-C/metabolismo , Osteoblastos/metabolismo , Osteogénesis , Receptores del Factor Natriurético Atrial/metabolismo , Transducción de Señal , Soporte de PesoRESUMEN
This chapter describes the methods of isolation of mouse periosteal progenitor cells. There are three basic methods utilized. The bone grafting method was developed utilizing the fracture healing process to expand the progenitor populations. Bone capping methods requires enzymatic digestion and purification of cells from the native periosteum, while the Egression/Explant method requires the least manipulation with placement of cortical bone fragments with attached periosteum in a culture dish. Various cell surface antibodies have been employed over the years to characterize periosteum derived progenitor cells, but the most consistent minimal criteria was recommended by the International Society for Cellular Therapy. Confirmation of the multipotent status of these isolated cells can be achieved by differentiation into the three basic mesodermal lineages in vitro.
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Trasplante Óseo/métodos , Técnicas de Cultivo de Célula/métodos , Periostio/crecimiento & desarrollo , Células Madre/citología , Animales , Diferenciación Celular/genética , Proliferación Celular/genética , Células Madre Mesenquimatosas/citología , Ratones , Osteogénesis/genética , Periostio/citologíaRESUMEN
Chondrocytes proliferate and mature into hypertrophic chondrocytes. Vascular invasion into the cartilage occurs in the terminal hypertrophic chondrocyte layer, and terminal hypertrophic chondrocytes die by apoptosis or transdifferentiate into osteoblasts. Runx2 is essential for osteoblast differentiation and chondrocyte maturation. Runx2-deficient mice are composed of cartilaginous skeletons and lack the vascular invasion into the cartilage. However, the requirement of Runx2 in the vascular invasion into the cartilage, mechanism of chondrocyte transdifferentiation to osteoblasts, and its significance in bone development remain to be elucidated. To investigate these points, we generated Runx2fl/flCre mice, in which Runx2 was deleted in hypertrophic chondrocytes using Col10a1 Cre. Vascular invasion into the cartilage was similarly observed in Runx2fl/fl and Runx2fl/flCre mice. Vegfa expression was reduced in the terminal hypertrophic chondrocytes in Runx2fl/flCre mice, but Vegfa was strongly expressed in osteoblasts in the bone collar, suggesting that Vegfa expression in bone collar osteoblasts is sufficient for vascular invasion into the cartilage. The apoptosis of terminal hypertrophic chondrocytes was increased and their transdifferentiation was interrupted in Runx2fl/flCre mice, leading to lack of primary spongiosa and osteoblasts in the region at E16.5. The osteoblasts appeared in this region at E17.5 in the absence of transdifferentiation, and the number of osteoblasts and the formation of primary spongiosa, but not secondary spongiosa, reached to levels similar those in Runx2fl/fl mice at birth. The bone structure and volume and all bone histomophometric parameters were similar between Runx2fl/fl and Runx2fl/flCre mice after 6 weeks of age. These findings indicate that Runx2 expression in terminal hypertrophic chondrocytes is not required for vascular invasion into the cartilage, but is for their survival and transdifferentiation into osteoblasts, and that the transdifferentiation is necessary for trabecular bone formation in embryonic and neonatal stages, but not for acquiring normal bone structure and volume in young and adult mice.
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Transdiferenciación Celular/genética , Condrocitos/fisiología , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Osteoblastos/fisiología , Osteogénesis/genética , Factores de Edad , Animales , Apoptosis/genética , Hueso Esponjoso/citología , Hueso Esponjoso/embriología , Hueso Esponjoso/crecimiento & desarrollo , Cartílago/irrigación sanguínea , Cartílago/citología , Cartílago/metabolismo , Supervivencia Celular/genética , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Embrión de Mamíferos , Femenino , Regulación del Desarrollo de la Expresión Génica , Masculino , Ratones , Ratones Noqueados , Modelos Animales , Periostio/citología , Periostio/embriología , Periostio/crecimiento & desarrollo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Nuclear factor kappa B (NF-κB) regulates inflammatory gene expression and represents a likely target for novel disease treatment approaches, including skeletal disorders. Several plant-derived sesquiterpene lactones can inhibit the activation of NF-κB. Parthenolide (PTL) is an abundant sesquiterpene lactone, found in Mexican Indian Asteraceae family plants, with reported anti-inflammatory activity, through the inhibition of a common step in the NF-κB activation pathway. This study examined the effects of PTL on the enhanced, in vitro, osteogenic phenotypes of human periosteum-derived cells (hPDCs), mediated by the inflammatory cytokine tumor necrosis factor (TNF)-α. PTL had no significant effects on hPDC viability or osteoblastic activities, whereas TNF-α had positive effects on the in vitro osteoblastic differentiation of hPDCs. c-Jun N-terminal kinase (JNK) signaling played an important role in the enhanced osteoblastic differentiation of TNF-α-treated hPDCs. Treatment with 1 µM PTL did not affect TNF-α-treated hPDCs; however, 5 and 10 µM PTL treatment decreased the histochemical detection and activity of alkaline phosphatase (ALP), alizarin red-positive mineralization, and the expression of ALP and osteocalcin mRNA. JNK phosphorylation decreased significantly in TNF-α-treated hPDCs pretreated with PTL. These results suggested that PTL exerts negative effects on the increased osteoblastic differentiation of TNF-α-treated hPDCs by inhibiting JNK signaling.
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Asteraceae/química , Inflamación/tratamiento farmacológico , Osteogénesis/efectos de los fármacos , Sesquiterpenos/farmacología , Diferenciación Celular/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Humanos , Hidrolasas/genética , Inflamación/genética , Inflamación/patología , Proteínas Quinasas JNK Activadas por Mitógenos , Lactonas/química , Lactonas/farmacología , Sistema de Señalización de MAP Quinasas , FN-kappa B , Osteoblastos/efectos de los fármacos , Osteogénesis/genética , Periostio/efectos de los fármacos , Periostio/crecimiento & desarrollo , Fenotipo , Fosforilación/efectos de los fármacos , Fosforilación/genética , Sesquiterpenos/química , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Quantifying joint deformity in people with rheumatoid (RA) and psoriatic arthritis (PsA) remains challenging. Here, we demonstrate a new method to measure bone erosions and abnormal periosteal growths, based on the difference between a predicted healthy and actual diseased joint surface. We optimized the method by creating and measuring artificial bone erosions and growths. Then we measured 46 healthy and diseased patient surfaces. We found average sensitivity errors of ≤0.27 mm when measuring artificial erosions and growths. Patients had significantly more bone erosion than healthy subjects. Surface based outcomes are a novel way to interpret and quantify bone changes in PsA and RA.
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Artritis Psoriásica/diagnóstico por imagen , Artritis Psoriásica/patología , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/patología , Procesamiento de Imagen Asistido por Computador , Articulaciones/diagnóstico por imagen , Articulaciones/patología , Algoritmos , Estudios de Cohortes , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Periostio/diagnóstico por imagen , Periostio/crecimiento & desarrollo , Periostio/patología , Proyectos PilotoRESUMEN
An approach to model the effect of exercise on the growth of mammal long bones is described. A Ginzburg-Landau partial differential equation system is utilised to study the change of size and shape of a cross-section caused by mechanically enhanced bone growth. The concept is based on a phase variable that keeps track of the material properties during the evolution of the bone. The relevant free energies are assumed to be elastic strain energy, concentration gradient energy and a double well chemical potential. The equation governing the evolution of the phase is derived from the total free energy and put on a non-dimensional form, which reduces all required information regarding load, material and cross-section size to one single parameter. The partial differential equation is solved numerically for the geometry of a cross-section using a finite element method. Bending in both moving and fixed directions is investigated regarding reshaping and growth rates. A critical non-zero load is found under which the bone is resorbed. The result for bending around a fixed axis can be compared with experiments made on turkeys. Three loading intervals are identified, I) low load giving resorption of bone on the external periosteum and the internal endosteum, II) intermediate load with growth at the periosteum and resorption at endosteum and III) large loads with growth at both periosteum and endosteum. In the latter case the extent of the medullary cavity decreases.
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Desarrollo Óseo/fisiología , Modelos Teóricos , Periostio/crecimiento & desarrollo , Animales , Análisis de Elementos Finitos , Humanos , Modelos BiológicosRESUMEN
Two decades after signals controlling bone length were discovered, the endogenous ligands determining bone width remain unknown. We show that postnatal establishment of normal bone width in mice, as mediated by bone-forming activity of the periosteum, requires BMP signaling at the innermost layer of the periosteal niche. This developmental signaling center becomes quiescent during adult life. Its reactivation however, is necessary for periosteal growth, enhanced bone strength, and accelerated fracture repair in response to bone-anabolic therapies used in clinical orthopedic settings. Although many BMPs are expressed in bone, periosteal BMP signaling and bone formation require only Bmp2 in the Prx1-Cre lineage. Mechanistically, BMP2 functions downstream of Lrp5/6 pathway to activate a conserved regulatory element upstream of Sp7 via recruitment of Smad1 and Grhl3. Consistent with our findings, human variants of BMP2 and GRHL3 are associated with increased risk of fractures.
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Proteína Morfogenética Ósea 2/genética , Osteogénesis/genética , Periostio/crecimiento & desarrollo , Animales , Proliferación Celular/genética , Proteínas de Unión al ADN/genética , Fracturas Óseas/genética , Fracturas Óseas/patología , Regulación del Desarrollo de la Expresión Génica/genética , Proteínas de Homeodominio/genética , Humanos , Ratones , Periostio/metabolismo , Transducción de Señal/genética , Proteína Smad1/genética , Factor de Transcripción Sp7/genética , Factores de Transcripción/genéticaRESUMEN
OBJECTIVES: To evaluate whether the subperiosteal injection of simvastatin (SIM) with a novel in situ gel-forming system, SrHA/Alg (strontium hydroxyapatite/alginate), can stimulate vertical bone augmentation in a rat calvarial model. MATERIAL AND METHODS: The SrHA/Alg solution was synthesized and combined with different doses of SIM (0.01, 0.02, 0.1, and 0.2 mg) to form the following groups: (1) SrHA/Alg only, (2) SrHA/Alg/0.01, (3) SrHA/Alg/0.02, (4) SrHA/Alg/0.1, and (5) SrHA/Alg/0.2. The SIM release pattern was analyzed, and rat primary periosteum-derived cell (PDC) responses were investigated. Twenty male Wistar rats were enrolled in the calvarial subperiosteal injection experiment with each animal receiving a 200-µl single subperiosteal injection of SrHA/Alg with different amounts of SIM (0, 0.01, 0.02, and 0.1 mg) incorporated (n = 5). The 0.2 mg dose group was not tested in vivo due to the severe toxicity found in vitro. The new bone formation was assessed histologically and radiologically at 8 weeks. RESULTS: The slow release of SIM was confirmed, and PDC viability decreased in the SrHA/Alg/0.2 group. Alkaline phosphatase positive areas and mineralization areas were significantly greater in the SrHA/Alg/0.01 and SrHA/Alg/0.02 groups (p < .05). The mRNA expression level of Runx2 significantly increased in the SrHA/Alg/SIM-0.02 group by day 7 (p < .05) and significantly higher levels of VEGF were found in the SrHA/Alg/0.01 and SrHA/Alg/0.02 groups at different time points (p < .05). In vivo, no prominent clinical sign of inflammation was observed, and the most significant bone gain was shown in the SrHA/Alg/0.02 group (p < .05). The osteoclast formation within the newly formed bone area was reduced in the SrHA/Alg/0.1 group (p < .05). CONCLUSIONS: When combined with SrHA/Alg system, the 0.02 mg SIM seemed to be the optimal dose to stimulate subperiosteal bone formation without inducing inflammation. This combination may hold potential therapeutic benefits for clinical bone augmentation in a minimally invasive manner.
Asunto(s)
Aumento de la Cresta Alveolar/métodos , Osteogénesis por Distracción/métodos , Periostio/citología , Simvastatina/uso terapéutico , Alginatos/administración & dosificación , Alginatos/uso terapéutico , Animales , Relación Dosis-Respuesta a Droga , Geles/administración & dosificación , Geles/uso terapéutico , Ácido Glucurónico/administración & dosificación , Ácido Glucurónico/uso terapéutico , Ácidos Hexurónicos/administración & dosificación , Ácidos Hexurónicos/uso terapéutico , Hidroxiapatitas/administración & dosificación , Hidroxiapatitas/uso terapéutico , Técnicas In Vitro , Inyecciones , Masculino , Periostio/efectos de los fármacos , Periostio/crecimiento & desarrollo , Ratas , Ratas Wistar , Simvastatina/administración & dosificación , Estroncio/administración & dosificación , Estroncio/uso terapéuticoRESUMEN
In regenerative medicine, computer models describing bioreactor processes can assist in designing optimal process conditions leading to robust and economically viable products. In this study, we started from a (3D) mechanistic model describing the growth of neotissue, comprised of cells, and extracellular matrix, in a perfusion bioreactor set-up influenced by the scaffold geometry, flow-induced shear stress, and a number of metabolic factors. Subsequently, we applied model reduction by reformulating the problem from a set of partial differential equations into a set of ordinary differential equations. Comparing the reduced model results to the mechanistic model results and to dedicated experimental results assesses the reduction step quality. The obtained homogenized model is 105 fold faster than the 3D version, allowing the application of rigorous optimization techniques. Bayesian optimization was applied to find the medium refreshment regime in terms of frequency and percentage of medium replaced that would maximize neotissue growth kinetics during 21 days of culture. The simulation results indicated that maximum neotissue growth will occur for a high frequency and medium replacement percentage, a finding that is corroborated by reports in the literature. This study demonstrates an in silico strategy for bioprocess optimization paying particular attention to the reduction of the associated computational cost.
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Reactores Biológicos , Técnicas de Cultivo de Célula/métodos , Modelos Biológicos , Periostio/citología , Periostio/crecimiento & desarrollo , Ingeniería de Tejidos/métodos , Técnicas de Cultivo de Célula/instrumentación , Células Cultivadas , Humanos , Ingeniería de Tejidos/instrumentaciónRESUMEN
Stem/progenitor cell-based regenerative medicine using the osteoblast differentiation of mesenchymal stem cells (MSCs) is regarded as a promising approach for the therapeutic treatment of various bone defects. The effects of the osteogenic differentiation of stem/progenitor cells on osteoclast differentiation may have important implications for use in therapy. However, there is little data regarding the expression of osteoclastogenic proteins during osteoblastic differentiation of human periosteum-derived cells (hPDCs) and whether factors expressed during this process can modulate osteoclastogenesis. In the present study, we measured expression of RANKL in hPDCs undergoing osteoblastic differentiation and found that expression of RANKL mRNA was markedly increased in these cells in a time-dependent manner. RANKL protein expression was also significantly enhanced in osteogenic-conditioned media from hPDCs undergoing osteoblastic differentiation. We then isolated and cultured CD34+ hematopoietic stem cells (HSCs) from umbilical cord blood (UCB) mononuclear cells (MNCs) and found that these cells were well differentiated into several hematopoietic lineages. Finally, we co-cultured human trabecular bone osteoblasts (hOBs) with CD34+ HSCs and used the conditioned medium, collected from hPDCs during osteoblastic differentiation, to investigate whether factors produced during osteoblast maturation can affect osteoclast differentiation. Specifically, we measured the effect of this osteogenic-conditioned media on expression of osteoclastogenic markers and osteoclast cell number. We found that osteoclastic marker gene expression was highest in co-cultures incubated with the conditioned medium collected from hPDCs with the greatest level of osteogenic maturation. Although further study will be needed to clarify the precise mechanisms that underlie osteogenic-conditioned medium-regulated osteoclastogenesis, our results suggest that the osteogenic maturation of hPDCs could promote osteoclastic potential.
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Diferenciación Celular/genética , Medios de Cultivo Condicionados/farmacología , Osteogénesis/efectos de los fármacos , Ligando RANK/genética , Diferenciación Celular/efectos de los fármacos , Linaje de la Célula/efectos de los fármacos , Linaje de la Célula/genética , Medios de Cultivo Condicionados/metabolismo , Sangre Fetal/citología , Regulación del Desarrollo de la Expresión Génica , Células Madre Hematopoyéticas/efectos de los fármacos , Humanos , Células Madre Mesenquimatosas/efectos de los fármacos , Osteoblastos/citología , Osteoblastos/metabolismo , Osteoclastos/citología , Osteoclastos/metabolismo , Osteogénesis/genética , Periostio/citología , Periostio/crecimiento & desarrolloRESUMEN
Misty mice (m/m) have a loss of function mutation in Dock7 gene, a guanine nucleotide exchange factor, resulting in low bone mineral density, uncoupled bone remodeling and reduced bone formation. Dock7 has been identified as a modulator of osteoblast number and in vitro osteogenic differentiation in calvarial osteoblast culture. In addition, m/m exhibit reduced preformed brown adipose tissue innervation and temperature as well as compensatory increase in beige adipocyte markers. While the low bone mineral density phenotype is in part due to higher sympathetic nervous system (SNS) drive in young mice, it is unclear what effect aging would have in mice homozygous for the mutation in the Dock7 gene. We hypothesized that age-related trabecular bone loss and periosteal envelope expansion would be altered in m/m. To test this hypothesis, we comprehensively characterized the skeletal phenotype of m/m at 16, 32, 52, and 78wks of age. When compared to age-matched wild-type control mice (+/+), m/m had lower areal bone mineral density (aBMD) and areal bone mineral content (aBMC). Similarly, both femoral and vertebral BV/TV, Tb.N, and Conn.D were decreased in m/m while there was also an increase in Tb.Sp. As low bone mineral density and decreased trabecular bone were already present at 16wks of age in m/m and persisted throughout life, changes in age-related trabecular bone loss were not observed highlighting the role of Dock7 in controlling trabecular bone acquisition or bone loss prior to 16wks of age. Cortical thickness was also lower in the m/m across all ages. Periosteal and endosteal circumferences were higher in m/m compared to +/+ at 16wks. However, endosteal and periosteal expansion were attenuated in m/m, resulting in m/m having lower periosteal and endosteal circumferences by 78wks of age compared to +/+, highlighting the critical role of Dock7 in appositional bone expansion. Histomorphometry revealed that osteoblasts were nearly undetectable in m/m and marrow adipocytes were elevated 3.5 fold over +/+ (p=0.014). Consistent with reduced bone formation, osteoblast gene expression of Alp, Col1a1, Runx-2, Sp7, and Bglap was significantly decreased in m/m whole bone. Furthermore, markers of osteoclasts were either unchanged or suppressed. Bone marrow stromal cell migration and motility were inhibited in culture and changes in senescence markers suggest that osteoblast function may also be inhibited with loss of Dock7 expression in m/m. Finally, increased Oil Red O staining in m/m ear mesenchymal stem cells during adipogenesis highlights a potential shift of cells from the osteogenic to adipogenic lineages. In summary, loss of Dock7 in the aging m/m resulted in an impairment of periosteal and endocortical envelope expansion, but did not alter age-related trabecular bone loss. These studies establish Dock7 as a critical regulator of both cortical and trabecular bone mass, and demonstrate for the first time a novel role of Dock7 in modulating compensatory changes in the periosteum with aging.
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Envejecimiento/patología , Hueso Esponjoso/patología , Factores de Intercambio de Guanina Nucleótido/genética , Mutación/genética , Periostio/patología , Adipocitos/metabolismo , Adipogénesis , Tejido Adiposo/metabolismo , Adiposidad , Animales , Biomarcadores/sangre , Densidad Ósea , Resorción Ósea/sangre , Resorción Ósea/patología , Hueso Esponjoso/metabolismo , Recuento de Células , Movimiento Celular , Femenino , Proteínas Activadoras de GTPasa , Regulación de la Expresión Génica , Factores de Intercambio de Guanina Nucleótido/metabolismo , Células Madre Mesenquimatosas/metabolismo , Ratones Endogámicos C57BL , Ratones Transgénicos , Tamaño de los Órganos , Osteoblastos/metabolismo , Osteoblastos/patología , Periostio/crecimiento & desarrollo , Fenotipo , Sistema Nervioso Simpático/metabolismoRESUMEN
The periosteum plays a critical role in bone homeostasis and regeneration. It contains a vascular component that provides vital blood supply to the cortical bone and an osteogenic niche that acts as a source of bone-forming cells. Periosteal grafts have shown promise in the regeneration of critical size defects, however their limited availability restricts their widespread clinical application. Only a small number of tissue-engineered periosteum constructs (TEPCs) have been reported in the literature. A current challenge in the development of appropriate TEPCs is a lack of pre-clinical models in which they can reliably be evaluated. In this study, we present a novel periosteum tissue engineering concept utilizing a multiphasic scaffold design in combination with different human cell types for periosteal regeneration in an orthotopic in vivo platform. Human endothelial and bone marrow mesenchymal stem cells (BM-MSCs) were used to mirror both the vascular and osteogenic niche respectively. Immunohistochemistry showed that the BM-MSCs maintained their undifferentiated phenotype. The human endothelial cells developed into mature vessels and connected to host vasculature. The addition of an in vitro engineered endothelial network increased vascularization in comparison to cell-free constructs. Altogether, the results showed that the human TEPC (hTEPC) successfully recapitulated the osteogenic and vascular niche of native periosteum, and that the presented orthotopic xenograft model provides a suitable in vivo environment for evaluating scaffold-based tissue engineering concepts exploiting human cells.
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Órganos Bioartificiales , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/fisiología , Periostio/citología , Periostio/crecimiento & desarrollo , Ingeniería de Tejidos/instrumentación , Andamios del Tejido , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Humanos , Técnicas de Cultivo de Órganos/instrumentación , Técnicas de Cultivo de Órganos/métodos , Ingeniería de Tejidos/métodosRESUMEN
Recombinant basic fibroblast growth factor (bFGF) is a potent mitogen for mesenchymal cells that accelerates bone union and repair when applied locally at defect sites. However, because bFGF diffuses rapidly from bone defect sites, repeated dosing is required for sustained therapeutic effect. We previously fused the collagen-binding domain (CBD) and polycystic kidney disease (PKD) domain of Clostridium histolyticum class II collagenase (ColH) to bFGF and demonstrated that the fusion protein markedly enhances bone formation when loaded onto collagen materials used for grafting. However, systemic injection of a fusion protein consisting of parathyroid hormone (PTH) and a CBD was shown to accelerate bone formation in an osteoporosis model more rapidly than treatment with a PTH-PKD-CBD fusion protein. Here, we compared the biological properties of two collagen-binding forms of bFGF, bFGF-CBD and bFGF-PKD-CBD. Both fusion proteins promoted the in vitro proliferation of periosteal mesenchymal cells, indicating that they had biological activity similar to that of native bFGF. In vivo periosteal bone formation assays in rat femurs showed that both bFGF-CBD and bFGF-PKD-CBD induced periosteal bone formation at higher rates than collagen sheet alone and bFGF. However, bFGF-PKD-CBD markedly enhanced bone formation and had higher collagen-binding ability than bFGF-CBD in in vitro protein release assays. Taken together, these results suggest that the PKD domain increases the retention of bFGF at graft sites by enhancing collagen-binding affinity. Therefore, bFGF-PKD-CBD-collagen composite appears to be a promising material for bone repair in the clinical setting. Copyright © 2015 John Wiley & Sons, Ltd.
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Factor 2 de Crecimiento de Fibroblastos/química , Factor 2 de Crecimiento de Fibroblastos/farmacología , Colagenasa Microbiana/química , Osteogénesis/efectos de los fármacos , Periostio/crecimiento & desarrollo , Animales , Proliferación Celular/efectos de los fármacos , Colágeno/química , Imagenología Tridimensional , Inyecciones , Masculino , Dominios Proteicos , Ratas , Proteínas Recombinantes de Fusión/farmacología , Microtomografía por Rayos XRESUMEN
In addition to conveying the forces of attaching muscles and ligaments to the zygomatic and temporal bones, the arch periosteum is responsible for lateral apposition and medial resorption during the growth period. In this contribution, we describe the vasculature of the zygomatic arch in young pigs (Sus scrofa dom.) in order to understand the relationship of osseous and periosteal vessels to each other, to surrounding tissues, and to patterns of modeling. Subjects 2-6 weeks of age were perfused with vascular fill; some also received the vital bone label calcein. Whole mounts were prepared of the decalcified bony arch and of its lateral periosteum. Undecalcified arches were plastic-embedded and thick-sectioned. Additional observations on cell replication were made using material from a previous study. The osseous and periosteal vascular supplies were largely independent, joined only by a fine network at the tissue interface. Osseous vessels entered the medial side of the arch through clusters of nutrient foramina. The intraosseous branching pattern resembled the direction of appositional growth, which in turn describes the disposition of bony trabeculae in older pigs. In contrast, vessels arrived at the periosteum via muscles and ligaments and thus its perfusion may partially depend on functional activity. The open weave of periosteal vessels bore little similarity to bone architecture, especially for the temporal bone, but the appositional lateral periosteum showed indications of angiogenesis, whereas the thinner, resorptive periosteum on the medial side featured composite, possibly fusing vessels at the bone surface. Anat Rec, 299:1661-1670, 2016. © 2016 Wiley Periodicals, Inc.
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Neovascularización Fisiológica/fisiología , Periostio/irrigación sanguínea , Cigoma/irrigación sanguínea , Animales , Periostio/anatomía & histología , Periostio/crecimiento & desarrollo , Sus scrofa , Cigoma/anatomía & histología , Cigoma/crecimiento & desarrolloRESUMEN
PURPOSE: The accepted mechanism explaining the accelerated growth following periosteal resection is that the periosteum serves as a mechanical restraint to restrict physeal growth. To test the veracity of this mechanism we first utilized Second Harmonic Generation (SHG) imaging to measure differences of periosteal fiber alignment at various strains. Additionally, we measured changes in periosteal growth factor transcription. Next we utilized SHG imaging to assess the alignment of the periosteal fibers on the bone both before and after periosteal resection. Based on the currently accepted mechanism, we hypothesized that the periosteal fibers adjacent to the physis should be more aligned (under tension) during growth and become less aligned (more relaxed) following metaphyseal periosteal resection. In addition, we measured the changes in periosteal micro- and macro-scale mechanics. METHODS: 30 seven-week old New Zealand White rabbits were sacrificed. The periosteum was imaged on the bone at five regions using SHG imaging. One centimeter periosteal resections were then performed at the proximal tibial metaphyses. The resected periosteal strips were stretched to different strains in a materials testing system (MTS), fixed, and imaged using SHG microscopy. Collagen fiber alignment at each strain was then determined computationally using CurveAlign. In addition, periosteal strips underwent biomechanical testing in both circumferential and axial directions to determine modulus, failure stress, and failure strain. Relative mRNA expression of growth factors: TGFß-1, -2, -3, Ihh, PTHrP, Gli, and Patched were measured following loading of the periosteal strips at physiological strains in a bioreactor. The periosteum adjacent to the physis of six tibiae was imaged on the bone, before and after, metaphyseal periosteal resection, and fiber alignment was computed. One-way ANOVA statistics were performed on all data. RESULTS: Imaging of the periosteum at different regions of the bone demonstrated complex regional differences in fiber orientation. Increasing periosteal strain on the resected strips increased periosteal fiber alignment (p<0.0001). The only exception to this pattern was the 10% strain on the tibial periosteum, which may indicate fiber rupture at this non-physiologic strain. Periosteal fiber alignment adjacent to the resection became less aligned while those adjacent to the physes remained relatively unchanged before and after periosteal resection. Increasing periosteal strain on the resected strips increased periosteal fiber alignment (p<0.0001). The only exception to this pattern was the 10% strain on the tibial periosteum, which may indicate fiber rupture (and consequent retraction) at this non-physiologic strain. Increasing periosteal strain revealed a significant increase in relative mRNA expression for Ihh, PTHrP, Gli, and Patched, respectively. CONCLUSION: Periosteal fibers adjacent to the growth plate do not appear under tension in the growing limb, and the alignments of these fibers remain unchanged following periosteal resection. SIGNIFICANCE: The results of this study call into question the long-accepted role of the periosteum acting as a simple mechanical tether restricting growth at the physis.
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Desarrollo Óseo/fisiología , Periostio/diagnóstico por imagen , Periostio/crecimiento & desarrollo , Microscopía de Generación del Segundo Armónico/métodos , Animales , Conejos , Estrés MecánicoRESUMEN
The treatment of bone defects is challenging and controversial. As a new technology, periosteal distraction osteogenesis (PDO) uses the osteogenicity of periosteum, which creates an artificial space between the bone surface and periosteum to generate new bone by gradually expanding the periosteum with no need for corticotomy. Using the newly formed bone of PDO to treat bone defects is effective, which can not only avoid the occurrence of immune-related complications, but also solve the problem of insufficient donor. This review elucidates the availability of PDO in the aspects of mechanisms, devices, strategies, and measures. Moreover, we also focus on the future prospects of PDO and hope that PDO will be applied to the clinical treatment of bone defects in the future.
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Regeneración Ósea , Osteogénesis por Distracción/métodos , Periostio/crecimiento & desarrollo , Animales , Humanos , Mandíbula/crecimiento & desarrollo , Mandíbula/fisiopatología , Conejos , RatasRESUMEN
The periosteum contributes to bone repair and maintenance of cortical bone mass. In contrast to the understanding of bone development within the epiphyseal growth plate, factors that regulate periosteal osteogenesis have not been studied as intensively. Osteofibrous dysplasia (OFD) is a congenital disorder of osteogenesis and is typically sporadic and characterized by radiolucent lesions affecting the cortical bone immediately under the periosteum of the tibia and fibula. We identified germline mutations in MET, encoding a receptor tyrosine kinase, that segregate with an autosomal-dominant form of OFD in three families and a mutation in a fourth affected subject from a simplex family and with bilateral disease. Mutations identified in all families with dominant inheritance and in the one simplex subject with bilateral disease abolished the splice inclusion of exon 14 in MET transcripts, which resulted in a MET receptor (MET(Δ14)) lacking a cytoplasmic juxtamembrane domain. Splice exclusion of this domain occurs during normal embryonic development, and forced induction of this exon-exclusion event retarded osteoblastic differentiation in vitro and inhibited bone-matrix mineralization. In an additional subject with unilateral OFD, we identified a somatic MET mutation, also affecting exon 14, that substituted a tyrosine residue critical for MET receptor turnover and, as in the case of the MET(Δ14) mutations, had a stabilizing effect on the mature protein. Taken together, these data show that aberrant MET regulation via the juxtamembrane domain subverts core MET receptor functions that regulate osteogenesis within cortical diaphyseal bone.
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Enfermedades del Desarrollo Óseo/genética , Exones , Mutación de Línea Germinal , Osteogénesis/genética , Periostio/metabolismo , Proteínas Proto-Oncogénicas c-met/genética , Adulto , Secuencia de Bases , Enfermedades del Desarrollo Óseo/metabolismo , Enfermedades del Desarrollo Óseo/patología , Diferenciación Celular , Niño , Femenino , Regulación del Desarrollo de la Expresión Génica , Genes Dominantes , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Osteoblastos/metabolismo , Osteoblastos/patología , Linaje , Periostio/crecimiento & desarrollo , Periostio/patología , Cultivo Primario de Células , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas c-met/metabolismo , Empalme del ARNRESUMEN
Childhood cortical porosity is attributable to giant asymmetrical drifting osteonal canals that arise predominantly along the primary-secondary bone interface (PSBI). Bone from the external iliac crest cortex of 92 subjects aged 0 to 25 years was examined histomorphometrically for differences in microstructural properties between primary and secondary bone that might account for features of drifting osteonal canals. Primary compared with secondary bone showed greater numbers of osteocyte lacunae, thinner collagen lamellae, and a scaffold of elastic perforating fibers (PFs). The greater number of osteocyte lacunae compounded by known perilacunar strain amplification and the presence of elastic PFs are expected to be associated with greater bone tissue strain in primary than in secondary bone and thus with strain gradients at the PSBI. Strain gradients may lead local osteocytes to originate resorption canals and to promote transverse drift of the resorption front into lower-strain secondary bone, thus creating giant asymmetrical drifting osteonal canals that remodel primary to secondary bone. PFs extended from muscle fibers through periosteum and primary bone to the PSBI, where they were resorbed by origination of drifting canals. Growth modeling by periosteal osteoblasts proceeds in the gaps between PFs. Through the direct connection between muscle and the PSBI via PFs, muscle forces may influence not only modeling by raising strain but also remodeling of primary to secondary bone by increasing strain gradients at the PSBI. With reduction in primary bone width after the mid-teens, numbers of drifting canals and porosity declined. Differences in microstructural properties between primary and secondary bone are expected to generate strain gradients at the PSBI that contribute to site, transverse drift, asymmetry and large size of drifting canals, and, hence, to cortical porosity. Cortical porosity in children is a physiological feature of bone growth in width. Advisability of therapeutic intervention remains to be defined.
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Desarrollo Óseo/fisiología , Remodelación Ósea , Ilion , Músculo Esquelético , Osteoblastos/metabolismo , Periostio , Adolescente , Adulto , Niño , Preescolar , Estudios Transversales , Humanos , Ilion/crecimiento & desarrollo , Ilion/metabolismo , Lactante , Recién Nacido , Masculino , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/metabolismo , Periostio/crecimiento & desarrollo , Periostio/metabolismo , PorosidadRESUMEN
The cartilage- and bone-forming properties of the periosteum have long since been recognized. As one of the major sources of skeletal progenitor cells, the periosteum plays a crucial role not only in bone development and growth, but also during bone fracture healing. Aided by the continuous expansion of tools and techniques, we are now starting to acquire more insight into the specific role and regulation of periosteal cells. From a therapeutic point of view, the periosteum has attracted much attention as a cell source for bone tissue engineering purposes. This interest derives not only from the physiological role of the periosteum during bone repair, but is also supported by the unique properties and marked bone-forming potential of expanded periosteum-derived cells. We provide an overview of the current knowledge of periosteal cell biology, focusing on the cellular composition and molecular regulation of this remarkable tissue, as well as the application of periosteum-derived cells in regenerative medicine approaches. This article is part of a Special Issue entitled "Stem Cells and Bone".
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Periostio/crecimiento & desarrollo , Regeneración/fisiología , Células Madre/citología , Animales , Desarrollo Óseo , Regeneración Ósea , Humanos , Ingeniería de TejidosRESUMEN
BACKGROUND AND OBJECTIVE: The jaw bone, unlike most other bones, is derived from neural crest stem cells, so we hypothesized that it may have different characteristics to bones from other parts of the body, especially in the nature of its periosteum. The periosteum exhibits osteogenic potential and has received considerable attention as a grafting material for the repair of bone and joint defects. MATERIAL AND METHODS: Gene expression profiles of jaw bone and periosteum were evaluated by DNA microarray and real-time polymerase chain reaction. Furthermore, we perforated an area 2 mm in diameter on mouse frontal and parietal bones. Bone regeneration of these calvarial defects was evaluated using microcomputed tomography and histological analysis. RESULTS: The DNA microarray data revealed close homology between the gene expression profiles within the ilium and femur. The gene expression of Wnt-1, SOX10, nestin, and musashi-1 were significantly higher in the jaw bone than in other locations. Microcomputed tomography and histological analysis revealed that the jaw bone had superior bone regenerative abilities than other bones. CONCLUSION: Jaw bone periosteum exhibits a unique gene expression profile that is associated with neural crest cells and has a positive influence on bone regeneration when used as a graft material to repair bone defects. A full investigation of the biological and mechanical properties of jaw bone as an alternative graft material for jaw reconstructive surgery is recommended.