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BACKGROUND: The purpose of this retrospective study was to evaluate the clinical efficacy of mineralized collagen (MC) versus anorganic bovine bone (Bio-Oss) for immediate implant placement in esthetic area. METHODS: Medical records of Department of Oral and Maxillofacial Surgery of Shandong Provincial Hospital were screened for patients who had been treated with immediate implant implantation in the esthetic area using either MC (Allgens®, Beijing Allgens Medical Science and Technology Co., Ltd., China) or Bio-Oss (Bio-Oss®, Geistlich Biomaterials, Wolhusen, Switzerland), between January 2018 and December 2019. All patients fulfilling the in-/exclusion criteria and following followed for a minimum period of 1 year after surgery were enrolled into the presented study. Implant survival rate, radiographic, esthetic and patient satisfactory evaluations were performed. RESULTS: Altogether, 70 patients were included in the study; a total of 80 implants were inserted. All implants had good initial stability. The survival rate of implants was 100% at 1-year follow-up. The differences in horizontal and vertical bone loss between the MC group (0.72 ± 0.26 mm, 1.62 ± 0.84 mm) and the Bio-Oss group (0.70 ± 0.52 mm, 1.57 ± 0.88 mm) were no significant difference statistically no significant 6 months after permanent restoration. Similar results occurred at 12 months after permanent restoration functional loaded. Clinical acceptability defined by pink esthetic score (PES) ≥ 6 (6.07 ± 1.62 vs. 6.13 ± 1.41) was not significantly different between groups. Patient satisfaction estimated by visual analog scale (VAS) was similar (8.56 ± 1.12 vs. 8.27 ± 1.44), and the difference was no significant difference between the two groups. CONCLUSIONS: The biomimetic MC showed a similar behaviour as Bio-Oss not only in its dimensional tissues changes but also in clinical acceptability and patient satisfaction. Within the limitations of this study, these cases show that MC could be considered as an alternative bone graft in IIP.
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Substitutos Ósseos , Implantes Dentários , Animais , Substitutos Ósseos/uso terapêutico , Bovinos , Colágeno , Implantação Dentária Endóssea , Falha de Restauração Dentária , Estética Dentária , Humanos , Minerais , Estudos Retrospectivos , Resultado do TratamentoRESUMO
[This corrects the article DOI: 10.1093/rb/rbaa022.].
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Repairing damage in the craniofacial skeleton is challenging. Craniofacial bones require intramembranous ossification to generate tissue-engineered bone grafts via angiogenesis and osteogenesis. Here, we designed a mineralized collagen delivery system for BMP-2 and vascular endothelial growth factor (VEGF) for implantation into animal models of mandibular defects. BMP-2/VEGF were mixed with mineralized collagen which was implanted into the rabbit mandibular. Animals were divided into (i) controls with no growth factors; (ii) BMP-2 alone; or (iii) BMP-2 and VEGF combined. CT and hisomputed tomography and histological staining were performed to assess bone repair. New bone formation was higher in BMP-2 and BMP-2-VEGF groups in which angiogenesis and osteogenesis were enhanced. This highlights the use of mineralized collagen with BMP-2/VEGF as an effective alternative for bone regeneration.
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To examine the clinical effects of a new bone cement composed of poly(methyl methacrylate) (PMMA) and mineralized collagen (MC) compared with pure PMMA bone cement in treating osteoporotic vertebral compression fractures (OVCFs) in patients aged over 80. In all, 32 cases using pure PMMA bone cement and 31 cases using MC-modified PMMA (MC-PMMA) bone cement for OVCFs between June 2014 and March 2016 were screened as PMMA group and MC-PMMA group, respectively, with an average age of over 80. The operation duration, intraoperative blood loss, hospital stay, oswestry disability index (ODI), visual analogue scale (VAS), anterior vertebral height (AVH), intermediate vertebral height (IVH) and posterior vertebral height (PVH) of injured vertebrae, vertebral computed tomography value, re-fracture rate of adjacent vertebrae, correction rate of spinal kyphotic angle and wedge-shaped vertebra angle and surgical complications were compared between the two groups. In the early post-operative period, the VAS, ODI, AVH and IVH in MC-PMMA group were comparable to those in the traditional PMMA group. Moreover, the MC-PMMA group showed better effects compared with the PMMA group 12 months after surgery. Thus, this new bone cement has superior clinic effects in the long term.
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Understanding the interaction between biomaterials and the immune system has become increasingly important. Mineralized collagen (MC) has the same chemical components and microstructures to natural bone tissue, and is considered as a better biomaterial for bone prostheses compared to hydroxyapatite (HA). However, there is little information about how MC affects inflammatory responses. In this study, we investigate the inflammatory responses to MC and HA by culturing RAW264.7 cells on their surfaces. We observed that MC increases CD206+ staining and IL-10 (M2 macrophages), whereas HA shows cells expressing more CD86 and secreting more TNF-α. This result indicates that MC may attenuate inflammatory responses to implanted bone prostheses.
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Substitutos Ósseos/química , Colágeno/química , Durapatita/química , Macrófagos/metabolismo , Animais , Antígeno B7-2/metabolismo , Materiais Biocompatíveis , Adesão Celular , Citocinas/metabolismo , Inflamação , Interleucina-10/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/citologia , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Camundongos , Monócitos/citologia , Osteogênese , Fenótipo , Células RAW 264.7 , Receptores de Superfície Celular/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
This study was aimed at assessing the effects of the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane on alveolar ridge preservation in dogs. The third premolars in the bilateral maxilla of mongrel dogs ( N = 12) were extracted. Twenty-four alveolar sockets were thus randomly divided into three groups: membrane + collagen plug (MP, n = 8), nonmembrane + collagen plug (NP, n = 8) and blank group without any implantation (BG, n = 8). Radiographic assessment was carried out immediately and in the 2nd, 6th, and 12th week after surgery. The bone-repairing effects of the two grafts were respectively evaluated by clinical observation, X-ray micro-computed tomography examination, and histological analysis in the 8th and 12th week after surgery. Three groups presented excellent osseointegration without any inflammation or dehiscence. X-ray micro-computed tomography and histological assessment indicated that the ratios of new bone formation of MP group were significantly higher than those of NP group and BG group in the 8th and 12th week after surgery ( P < 0.05). As a result, the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane could reduce the absorption of alveolar ridge compared to BG group, and the combined use of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration could further improve the activity of bone regeneration.
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Processo Alveolar/fisiologia , Processo Alveolar/cirurgia , Regeneração Óssea , Substitutos Ósseos/química , Colágeno/química , Durapatita/química , Regeneração Tecidual Guiada Periodontal/métodos , Animais , Cães , Masculino , Membranas Artificiais , Osseointegração , Porosidade , Alvéolo Dental/fisiologia , Alvéolo Dental/cirurgiaRESUMO
Rib segment, as one of the most widely used autologous boneresources for bone repair, is commonly isolated with an empty left in the defect. Although defective rib repair is thought to be unnecessary traditionally, it's of vital importance actually to promote rib regeneration for patients with better postoperative recovery and higher life quality. Comparative investigations on rabbit rib bone regeneration with and without graft were reported in this article. A segmental defect was performed on the 8th rib of 4-month-old male New Zealand rabbits. The mineralized collagen bone graft (MC) was implanted into the defect and evaluated for up to 12 weeks. The rib bone repair was investigated by using X-ray at 4, 8 and 12 weeks and histological examinations at 12 weeks after surgery, which showed a higher bone remodeling activity in the groups with MC implantation in comparison with blank control group, especially at the early stage of remodeling.
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Regeneração Óssea , Transplante Ósseo/métodos , Costelas/cirurgia , Animais , Remodelação Óssea , Substitutos Ósseos , Calcificação Fisiológica , Colágeno , Masculino , Coelhos , Costelas/lesões , Alicerces Teciduais , CicatrizaçãoRESUMO
The complex interaction between extracellular matrix and cells makes the design of materials for dental regeneration challenging. Chemical composition is an important characteristic of biomaterial surfaces, which plays an essential role in modulating the adhesion and function of cells. The effect of different chemical groups on directing the fate of human dental pulp stem cells (hDPSCs) was thus explored in our study. A range of self-assembled monolayers (SAMs) with amino (-NH2), hydroxyl (-OH), carboxyl (-COOH), and methyl (-CH3) modifications were prepared. Proliferation, morphology, adhesion, and differentiation of hDPSCs were then analyzed to demonstrate the effects of surface chemical groups. The results showed that hDPSCs attached to the -NH2 surface displayed a highly branched osteocyte-like morphology with improved cell adhesion and proliferation abilities. Moreover, hDPSCs cultured on the -NH2 surface also tended to obtain an increased osteo/odontogenesis differentiation potential. However, the hDPSCs on the -COOH, -OH, and -CH3 surfaces preferred to maintain the mesenchymal stem cell-like phenotype. In summary, this study indicated the influence of chemical groups on hDPSCs in vitro and demonstrated that -NH2 might be a promising surface modification strategy to achieve improved biocompatibility, osteoconductivity/osteoinductivity, and osseointegration of dental implants, potentially facilitating dental tissue regeneration.
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PURPOSE: The purpose of this study was to present the outcome and discuss the feasibility of rib composite flap with intercostal nerve and internal thoracic vessels for reconstructing mandibular defect. METHODS: Rib composite flaps have been used in 82 patients for reconstructing benign tumor-caused large mandibular defects: 66 of the 82 patients were reconstructed using rib composite flap with intercostal nerve and internal thoracic vessels, whereas the other 16 patients were reconstructed using rib composite flap with internal thoracic vessels, without intercostal nerve. After operation, clinical observation, imageological examination, and sensory detection were used to evaluate the effect of reconstruction. RESULTS: All rib composite flaps with intercostal nerve and internal thoracic vessels were successfully harvested and transplanted. Both immediate and long-term examination showed good appearance reconstruction. All followed-up patients conveyed good satisfaction degree with function and appearance reconstruction. Postoperative panoramic x-ray examination showed new bone formation between the transplanted rib and mandibular stump. Good recoveries of mandibular nerve sensory were observed when followed up after reconstruction surgery. CONCLUSIONS: Rib composite flap with intercostal nerve and internal thoracic vessels could be a promising method for reconstruction of mandibular defects.
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Nervos Intercostais/cirurgia , Traumatismos Mandibulares/cirurgia , Reconstrução Mandibular/métodos , Costelas/transplante , Retalhos Cirúrgicos/irrigação sanguínea , Retalhos Cirúrgicos/inervação , Artérias Torácicas/cirurgia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
This study provided a new method to in vitro evaluate the biocompatibility of nanoscaled scaffolds for tissue engineering with neutrophils other than ordinary cell culture. The neutrophils were separated from human peripheral blood of healthy subjects. In vitro degradation product of nanohydroxyapatite/collagen (nHAC), nanohydroxyapatite/collagen/poly (L-lactic acid) (nHACP), and nHACP reinforced by chitin fibers (nHACP/CF) in the D-Hank's Balanced Salt Solution (D-HBSS) was used as the testing solution, which was thereafter mixed with the neutrophils. It was shown that the cell survival rate in the testing solutions had no significant difference from that in the D-HBSS (control). However, from both gene and protein expression levels, the lactate dehydrogenase and tumor necrosis factor-alpha of the neutrophils in the nHACP/CF testing solution were found lowest during the whole testing period; the main reasons of which might be that the calcium release rate of the scaffold was slowest and that the pH value of its degradation solution was nearest to that of human body. Moreover, in vivo experiments showed that most inflammation reactions happened for nHAC and poly (L-lactic acid) groups, while the least inflammation reactions happened for nHACP/CF group in the subcutaneous dorsum of mice at 2 weeks after the surgery, which confirmed the in vitro findings. These results indicated that the pH value and the certain metal iron concentration of the nanoscaled scaffold degradation solution should be two important factors that significantly affect its biocompatibility. This study provides a simple and effective biocompatibility test method for biodegradable nanoscaled tissue engineering scaffolds. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2117-2125, 2016.
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Quitina/química , Colágeno/química , Durapatita/química , Teste de Materiais/métodos , Nanopartículas/química , Neutrófilos/metabolismo , Alicerces Teciduais/química , Humanos , Neutrófilos/citologiaRESUMO
The aim of this study was to discuss the feasibility of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration membrane in site preservation in extraction sockets. The third mandibular premolars on both sides were extracted from four dogs, thus there were 16 alveolar sockets in all dogs and were randomly assigned into three groups. Group A had six alveolar sockets, and groups B and C had five alveolar sockets, respectively. Each alveolar socket of group A was immediately implanted with a porous mineralized collagen plug and covered with a bilayer mineralized collagen-guided bone regeneration membrane after tooth extraction. Alveolar sockets of group B were implanted with porous mineralized collagen plug only, and group C was set as blank control without any implantation. The healing effects of the extraction sockets were evaluated by gross observation, morphological measurements, and X-ray micro-computed tomography after twelve weeks. Twelve weeks after operation, both groups A and B had more amount of new bone formation compared with group C; in terms of the degree of alveolar bone height, group A was lower than groups B and C with significant differences; the bone mineral density in the region of interest and bone remodeling degree in group A were higher than those of groups B and C. As a result, porous mineralized collagen plug could induce the regeneration of new bone in extraction socket, and combined use of porous mineralized collagen plug and bilayer mineralized collagen guided bone regeneration membrane could further reduce the absorption of alveolar ridge and preserve the socket site.
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Dente Pré-Molar/cirurgia , Regeneração Óssea , Substitutos Ósseos/química , Colágeno/química , Extração Dentária/métodos , Alvéolo Dental/fisiologia , Processo Alveolar/fisiologia , Processo Alveolar/cirurgia , Processo Alveolar/ultraestrutura , Animais , Calcificação Fisiológica , Implantes Dentários , Cães , Membranas Artificiais , Porosidade , Alvéolo Dental/cirurgia , Alvéolo Dental/ultraestrutura , Cicatrização , Microtomografia por Raio-XRESUMO
It is generally recognized that nanoparticles possess unique physicochemical properties that are largely different from those of conventional materials, specifically the electromagnetic properties of magnetic nanoparticles (MNPs). These properties have attracted many researchers to launch investigations into their potential biomedical applications, which have been reviewed in this article. First, common types of MNPs were briefly introduced. Then, the biomedical applications of MNPs were reviewed in seven parts: magnetic resonance imaging (MRI), cancer therapy, the delivery of drugs and genes, bone and dental repair, tissue engineering, biosensors, and in other aspects, which indicated that MNPs possess great potentials for many kinds of biomedical applications due to their unique properties. Although lots of achievements have been obtained, there is still a lot of work to do. New synthesis techniques and methods are still needed to develop the MNPs with satisfactory biocompatibility. More effective methods need to be exploited to prepare MNPs-based composites with fine microstructures and high biomedical performances. Other promising research points include the development of more appropriate techniques of experiments both in vitro and in vivo to detect and analyze the biocompatibility and cytotoxicity of MNPs and understand the possible influencing mechanism of the two properties. More comprehensive investigations into the diagnostic and therapeutic applications of composites containing MNPs with "core-shell" structure and deeper understanding and further study into the properties of MNPs to reveal their new biomedical applications, are also described in the conclusion and perspectives part.
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Nanopartículas de Magnetita/química , Animais , Técnicas Biossensoriais/métodos , Sistemas de Liberação de Medicamentos/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Magnetismo/métodos , Nanopartículas de Magnetita/análise , Nanopartículas de Magnetita/uso terapêutico , Engenharia Tecidual/métodosRESUMO
Poly(methyl methacrylate) bone cement is widely used in vertebroplasty, joint replacement surgery, and other orthopaedic surgeries, while it also exposed many problems on mechanical property and biocompatibility. Better performance in mechanical match and bone integration is highly desirable. Recently, there reported that incorporation of mineralized collagen into poly(methyl methacrylate) showed positive results in mechanical property and osteointegration ability in vivo. In the present study, we focused on the comparison of osteogenic behavior between mineralized collagen incorporated in poly(methyl methacrylate) and poly(methyl methacrylate). Human marrow mesenchymal stem cells are used in this experiment. Adhesion and proliferation were used to characterize biocompatibility. Activity of alkaline phosphatase was used to assess the differentiation of human marrow mesenchymal stem cells into osteoblasts. Real-time PCR was performed to detect the expression of osteoblast-related markers at messenger RNA level. The results show that osteogenic differentiation on mineralized collagen incorporated in poly(methyl methacrylate) bone cement is more than two times higher than that of poly(methyl methacrylate) after culturing for 21 days. Thus, important mechanism on mineralized collagen incorporation increasing the osteogenetic ability of poly(methyl methacrylate) bone cement may be understood in this concern.
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Cimentos Ósseos/química , Colágeno/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Minerais/química , Polimetil Metacrilato/síntese química , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Cultivadas , Humanos , Teste de Materiais , Osteogênese/fisiologiaRESUMO
In this study, human mesenchymal stem cells (hMSCs) were cultured on the hydroxyapatite (HA) and mineralized collagen (MC), and their proliferation, adhesion, and differentiation, especially the molecular mechanisms on gene level, were investigated. Proliferation and morphological responses of hMSCs and their osteogenic differentiation were detected by quantitative detection of alkaline phosphatase. Gene expression profilings were examined by microarrays, and the gene expression data were studied through gene ontology terms and pathway analyses. The results showed that MC promoted cell proliferation and osteogenic differentiation of hMSCs. Microarray analysis showed that MC was conducive to express osteogenesis-related genes, such as BMP-2, COL1A1, and CTSK, and stimulate osteogenic differentiation, such as osteoblast differentiation pathway and skeletal system development pathway.
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Antígenos de Diferenciação/biossíntese , Diferenciação Celular/efeitos dos fármacos , Colágeno/metabolismo , Durapatita/farmacologia , Células-Tronco Mesenquimais/metabolismo , Osteogênese/efeitos dos fármacos , Perfilação da Expressão Gênica , Humanos , Células-Tronco Mesenquimais/citologiaRESUMO
Enhancement of osteogenic capacity was achieved in a mineralized collagen composite, nano-hydroxyapatite/collagen (nHAC), by loading with synthetic peptides derived from BMP-2 residues 32-48 (P17-BMP-2). Rabbit marrow stromal cells (MSCs) were used in vitro to study cell biocompatibility, attachment and differentiation on the mineralized collagen composite by a cell counting kit, scanning electron microscopy (SEM) and real-time reversed transcriptase-polymerase chain reaction analysis (RT-PCR). Optimal peptide dosage (1.0 µg/mL) was obtained by RT-PCR analysis in vitro. In addition, the relative expression level of OPN and OCN was significantly upregulated on P17-BMP-2/nHAC compared with nHAC. In vitro results of P17-BMP-2 release kinetics demonstrated that nHAC released P17-BMP-2 in a controlled and sustained manner. In the rabbit mandibular box-shaped bone defect model, osteogenic capacity of three groups (nHAC, P17-BMP-2/nHAC, rhBMP-2/nHAC) was evaluated. Compared to the nHAC group, bone repair responses in both P17-BMP-2/nHAC and rhBMP-2/nHAC group implants were significantly improved based on histological analysis. The osteogenic response of the P17-BMP-2/nHAC group was similar to that of the rhBMP-2/nHAC group.
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Proteína Morfogenética Óssea 2/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Colágeno/farmacologia , Durapatita/farmacologia , Minerais/farmacologia , Osteogênese/efeitos dos fármacos , Peptídeos/farmacologia , Fator de Crescimento Transformador beta/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Cinética , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Coelhos , Proteínas Recombinantes/farmacologiaRESUMO
Neural stem cells (NSCs) have been a promising candidate for stem cell-based nerve tissue regeneration. Therefore, the design of idea biomaterials that deliver precise regulatory signals to control stem cell fate is currently a crucial issue that depends on a profound understanding of the interactions between NSCs with the surrounding micro-environment. In this work, self-assembled monolayers of alkanethiols on gold with different chemical groups, including hydroxyl (-OH), amino (-NH2), carboxyl (-COOH) and methyl (-CH3), were used as a simple model to study the effects of surface chemistry on NSC fate decisions. Contact angle measurement and x-ray photoelectron spectroscopy (XPS) examination implied that all types of alkanethiols self-assembled on gold into a close-packed phase structure with similar molecular densities. In this study, we evaluated NSC adhesion, migration and differentiation in response to different chemical functional groups cultured under serum-free conditions. Our studies showed that NSCs exhibited certain phenotypes with extreme sensitivity to surface chemical groups. Compared with other functional groups, the SAMs with hydroxyl end-groups provided the best micro-environment in promoting NSC migration and maintaining an undifferentiated or neuronal differentiation state. -NH2 surfaces directed neural stem cells into astrocytic lineages, while NSCs on -COOH and -CH3 surfaces had a similar potency to differentiate into three nerve lineages. To further investigate the possible signaling pathway, the gene expression of integrin ß1 and ß4 were examined. The results indicated that a high expression of ß1 integrin would probably have a tight correlation with the expression of nestin, which implied the stemness of NSCs, while ß4 integrin seemed to correspond to the differentiated NSCs. The results presented here give useful information for the future design of biomaterials to regulate the preservation, proliferation and differentiation of NSCs for central nervous tissue engineering.
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Alcanos/química , Diferenciação Celular/fisiologia , Materiais Revestidos Biocompatíveis/síntese química , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Compostos de Sulfidrila/química , Animais , Adesão Celular/fisiologia , Linhagem Celular , Linhagem da Célula , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Cristalização/métodos , Ouro/química , Teste de Materiais , Ratos , Propriedades de Superfície , Engenharia Tecidual/métodosRESUMO
Bone regeneration is a complicated process that involves a series of biological events, such as cellular recruitment, proliferation and differentiation, and so forth, which have been found to be significantly affected by controlled drug delivery. Recently, a lot of research studies have been launched on the application of nanomaterials in controlled drug delivery for bone regeneration. In this article, the latest research progress in this area regarding the use of bioceramics-based, polymer-based, metallic oxide-based and other types of nanomaterials in controlled drug delivery for bone regeneration are reviewed and discussed, which indicates that the controlling drug delivery with nanomaterials should be a very promising treatment in orthopedics. Furthermore, some new challenges about the future research on the application of nanomaterials in controlled drug delivery for bone regeneration are described in the conclusion and perspectives part.
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Materiais Biocompatíveis/química , Regeneração Óssea/efeitos dos fármacos , Preparações de Ação Retardada/química , Sistemas de Liberação de Medicamentos/métodos , Nanoestruturas/química , Animais , Materiais Biocompatíveis/toxicidade , Preparações de Ação Retardada/toxicidade , Humanos , Nanoestruturas/toxicidade , Nanoestruturas/ultraestrutura , Nanotecnologia/métodosRESUMO
The migration of vascular endothelial cells (ECs) is essential for reendothelialization after implantation of cardiovascular biomaterials. Reendothelialization is largely determined by surface properties of implants. In this study, surfaces modified with various chemical functional groups (CH3, NH2, COOH, OH) prepared by self-assembled monolayers (SAMs) were used as model system. Expressions and distributions of critical proteins in the integrin-induced signaling pathway were examined to explore the mechanisms of surface chemistry regulating EC migration. The results showed that SAMs modulated cell migration were in the order CH3>NH2>OH>COOH, determined by differences in the expressions of focal adhesion components and Rho GTPases. Multiple integrin subunits showed difference in a surface chemistry-dependent manner, which induced a stepwise activation of signaling cascades associated with EC migration. This work provides a broad overview of surface chemistry regulated endothelial cell migration and establishes association among the surface chemistry, cell migration behavior and associated integrin signaling events. Understanding the relationship between these factors will help us to understand the surface/interface behavior between biomaterials and cells, reveal molecular mechanism of cells sensing surface characterization, and guide surface modification of cardiovascular implanted materials.
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Movimento Celular , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Integrinas/metabolismo , Células Cultivadas , Humanos , Integrinas/química , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
This paper presents a review of the rationale for the in vitro mineralization process, preparation methods, and clinical applications of mineralized collagen. The rationale for natural mineralized collagen and the related mineralization process has been investigated for decades. Based on the understanding of natural mineralized collagen and its formation process, many attempts have been made to prepare biomimetic materials that resemble natural mineralized collagen in both composition and structure. To date, a number of bone substitute materials have been developed based on the principles of mineralized collagen, and some of them have been commercialized and approved by regulatory agencies. The clinical outcomes of mineralized collagen are of significance to advance the evaluation and improvement of related medical device products. Some representative clinical cases have been reported, and there are more clinical applications and long-term follow-ups that currently being performed by many research groups.
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The aim of this study was to compare the effect of implantation site (i.e., subcutaneous, SQ vs. intramuscular, IM) on bone forming capacity of cell-based and growth factor-based scaffolds in athymic nude rats after an implantation period of 8 weeks. Cell-based scaffolds consisted of porous hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds seeded with either human adipose tissue-derived mesenchymal stem cells (AT-MSCs) only or both AT-MSCs and human umbilical vein endothelial cells (HUVECs), which were precultured in osteogenic medium for 7 days. Growth factor-based scaffolds consisted of porous HA/TCP scaffolds with 20 µg preadsorbed bone morphogenetic protein-2 (BMP-2). Histological and histomorphometrical analysis were used to assess bone formation. A differentiation experiment was performed in parallel to compare the in vitro osteogenic capacity of cell-based scaffolds. The results showed that cell-based scaffolds showed evident osteogenic differentiation in vitro, with only marginal differences between AT-MSCs only and AT-MSCs/HUVECs. In vivo, none of the cell-based scaffolds showed bone formation, irrespective of the site of implantation. In contrast, all growth factor-based scaffolds showed bone formation at both implantation sites without differences in the amount of formed bone. In conclusion, the results of this study demonstrated that the bone forming capacity of HA/TCP scaffolds with pre-adsorbed BMP-2 was equal at different ectopic implantation sites. Further, despite obvious in vitro osteogenic differentiation of AT-MSCs and AT-MSCS/HUVECs on HA/TCP scaffolds, no bone formation of these cell-based scaffolds was observed in vivo. This indicates further investigation on bone formation mechanisms of AT-MSCs is needed before AT-MSCs can be used as a cytotherapeutic treatment in clinics.