Suchergebnisse

Helin Xing,1,2 Satoshi Komasa,3 Yoichiro Taguchi,4 Tohru Sekino,5 Joji Okazaki3 1Department of Prosthetic Dentistry, School of Stomatology, The Fourth Military Medical University, Xi'an, People's Republic of China; 2Graduate School of Dentistry (Removable Prosthodontics and Occlusion), 3Department of Removable Prosthodontics and Occlusion, 4Department of Periodontology, Osaka Dental University, Hirakata, Osaka, Japan; 5Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai, Japan Background: Titanium surfaces play an important role in affecting osseointegration of dental implants. Previous studies have shown that the titania nanotube promotes osseointegration by enhancing osteogenic differentiation. Only relatively recently have the effects of titanium surfaces with other nanostructures on osteogenic differentiation been investigated. Methods: In this study, we used NaOH solutions with concentrations of 2.5, 5.0, 7.5, 10.0, and 12.5 M to develop a simple and useful titanium surface modification that introduces the nanonetwork structures with titania nanosheet (TNS) nanofeatures to the surface of titanium disks. The effects of such a modified nanonetwork structure, with different alkaline concentrations on the osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMMSCs), were evaluated. Results: The nanonetwork structures with TNS nanofeatures induced by alkali etching markedly enhanced BMMSC functions of cell adhesion and osteogenesis-related gene expression, and other cell behaviors such as proliferation, alkaline phosphatase activity, extracellular matrix deposition, and mineralization were also significantly increased. These effects were most pronounced when the concentration of NaOH was 10.0 M. Conclusion: The results suggest that nanonetwork structures with TNS nanofeatures improved BMMSC proliferation and induced BMMSC osteogenic differentiation. In addition, the surfaces formed with 10.0 M NaOH suggest the potential to improve the clinical performance of dental implants. Keywords: nanotopography, osseointegration, surface modification, bone marrow mesenchymal stem cells

Jianfei Liang,1,* Shanshan Xu,1,* Mingming Shen,2,* Bingkun Cheng,3 Yongfeng Li,4 Xiangwei Liu,1 Dongze Qin,1 Anuj Bellare,5 Liang Kong1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Disease & Shaanxi Key Laboratory of Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, 2Department of Stomatology, Xinhua Hospital of Beijing, Beijing, 3Department of Oral and Maxillofacial Surgery, School of Stomatology, The Second Hospital of Hebei Medical University, Shijiazhuang, 4Department of Stomatology, Chinese PLA 532 Hospital, Huangshan, People's Republic of China; 5Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA *These authors contributed equally to this work Abstract: An easier method for constructing the hierarchical micro-/nano-structures on the surface of dental implants in the clinic is needed. In this study, three different titanium surfaces with microscale grooves (width 0.5–1, 1–1.5, and 1.5–2 µm) and nanoscale nanoparticles (diameter 20–30, 30–50, and 50–100 nm, respectively) were obtained by treatment with different concentrations of hydrofluoric acid (HF) and at different etching times (1%, 3 min; 0.5%, 12 min; and 1.5%, 12 min, respectively; denoted as groups HF1, HF2, and HF3). The biological response to the three different titanium surfaces was evaluated by in vitro human bone marrow-derived mesenchymal stem cell (hBMMSC) experiments and in vivo animal experiments. The results showed that cell adhesion, proliferation, alkaline phosphatase activity, and mineralization of hBMMSCs were increased in the HF3 group. After the different surface implants were inserted into the distal femurs of 40 rats, the bone–implant contact in groups HF1, HF2, and HF3 was 33.17%±2.2%, 33.82%±3.42%, and 41.04%±3.08%, respectively. Moreover, the maximal pullout force in groups HF1, HF2, and HF3 was 57.92±2.88, 57.83±4.09, and 67.44±6.14 N, respectively. The results showed that group HF3 with large micron grooves (1.5–2.0 µm) and large nanoparticles (50–100 nm) showed the best bio-functionality for the hBMMSC response and osseointegration in animal experiments compared with other groups. Keywords: hydrofluoric acid etching, surface modification, micro-/nano-structures, osteogenic activity, titanium implant

Biocompatibility and bacterial infections are the primary concerns associated with the current bone graft substitutes. The application of wollastonite-based scaffolds for bone tissue engineering becomes a novel subject of interest. In the present study, a single phasic wollastonite scaffold was synthesised using citric acid-based sol–gel combustion route. Its physicochemical characteristics, antibacterial properties as well as its biocompatibility and osteogenic induction effect on human bone marrow derived stromal cells (hBMSCs) are yet to be explored. The TGA/DTA, XRD and SEM/EDX confirmed the characteristics of wollastonite. The antibacterial test indicated wollastonite inhibition of 47.81% and 45.54% for gram-positive, Staphylococcus aureus and Staphylococcus epidermidis and 47.04% and 46.07% for gram-negative, Escherichia coli and Pseudomonas aeruginosa bacterial strains, respectively. The SEM micrographs demonstrated an excellent attachment of hBMSCs on wollastonite and comparable to commercial hydroxyapatite (cHA) scaffold. The alamar blue cell proliferation assay confirmed 1.7- and 1.8-fold significant increase in hBMSCs seeded on wollastonite and cHA scaffold, respectively, on day 14 as compared with day 1. The immunohistochemistry analysis on Type-I collagen (Col1) and Bone morphogenetic protein-2 (BMP2) expression on day 14 confirmed the osteogenic differentiation of hBMSCs seeded on wollastonite and comparable with cHA scaffold. In conclusion, wollastonite scaffold has a greater potential to substitute bone grafts in orthopaedic applications. ; The authors acknowledge the Vellore Institute of Technology (VIT) management for the support and DST-FIST for the XRD and SEM-EDX facility. The authors gratefully acknowledge the financial support from the European Union's Horizon 2020 research and innovation programme under the grant agreement No. 857287. The authors would like to express their highest gratitude to Ministry of Higher Education for fundamental research grant scheme ...

How to surpass invitro stem cell differentiation, reducing cell manipulation, and lead the in situ regeneration process after transplantation, remains to be unraveled in bone tissue engineering (bTE). Recently, we showed that the combination of human bone marrow stromal cells with bioactive silicate nanoplatelets (sNPs) promotes the osteogenic differentiation without the use of standard osteogenic inductors. Even more, using SSEA-4(+) cell-subpopulations (SSEA-4(+)hASCs) residing within the adipose tissue, as a single-cellular source to obtain relevant cell types for bone regeneration, was also proposed. Herein, sNPs were used to promote the osteogenic differentiation of SSEA-4(+)hASCs. The interactions between SSEA-4(+)hASCs and sNPs, namely the internalization pathway and effect on cells osteogenic differentiation, were evaluated. SNPs below 100μg/mL showed high cytocompatibility and fast internalization via clathrin-mediated pathway. SNPs triggered an overexpression of osteogenic-related markers (RUNX2, osteopontin, osteocalcin) accompanied by increased alkaline phosphatase activity and deposition of a predominantly collagen-type I matrix. Consequently, a robust matrix mineralization was achieved, covering >90% of the culturing surface area. Overall, we demonstrated the high osteogenic differentiation potential of SSEA-4(+)hASCs, further enhanced by the addition of sNPs in a dose dependent manner. This strategy endorses the combination of an adipose-derived cell-subpopulation with inorganic compounds to achieve bone matrix-analogs with clinical relevance. ; Authors thank the Portuguese Foundation for Science and Technology (FCT) for the personal grant SFRH/BD/42968/2008 through the MIT-Portugal Program (SMM). The research leading to these results has received funding from the MIT/ECE/0047/2009 project and the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n degrees REGPOT-CT2012-316331-POLARIS and MIT/ECE/0047/2009 ...

[EN] The aim of this work was to determine the influence of the biomaterial environment on human mesenchymal stem cell (hMSC) fate when cultured in supports with varying topography. Poly(vinylidene fluoride) (PVDF) culture supports were prepared with structures ranging between 2D and 3D, based on PVDF films on which PVDF microspheres were deposited with varying surface density. Maintenance of multipotentiality when cultured in expansion medium was studied by flow cytometry monitoring the expression of characteristic hMSCs markers, and revealed that cells were losing their characteristic surface markers on these supports. Cell morphology was assessed by scanning electron microscopy (SEM). Alkaline phosphatase activity was also assessed after seven days of culture on expansion medium. On the other hand, osteoblastic differentiation was monitored while culturing in osteogenic medium after cells reached confluence. Osteocalcin immunocytochemistry and alizarin red assays were performed. We show that flow cytometry is a suitable technique for the study of the differentiation of hMSC seeded onto biomaterials, giving a quantitative reliable analysis of hMSC-associated markers. We also show that electrosprayed piezoelectric poly(vinylidene fluoride) is a suitable support for tissue engineering purposes, as hMSCs can proliferate, be viable and undergo osteogenic differentiation when chemically stimulated. ; The authors thank the Portuguese Foundation for Science and Technology (FCT) for financial support under project PTDC/EEI-SII/5582/2014, Strategic Funding UID/FIS/04650/2013 and grants SFRH/BPD/90870/2012 (C.R.) and SFRH/BPD/121526/2016 (D.M.C). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK program. JLGR, LC, RSS and AS acknowledge funding by the Conselleria de Educacion, Investigacion, Cultura y Deporte of the Generalitat Valenciana through ...

The aim of this work was to determine the influence of the biomaterial environment on human mesenchymal stem cell (hMSC) fate when cultured in supports with varying topography. Poly(vinylidene fluoride) (PVDF) culture supports were prepared with structures ranging between 2D and 3D, based on PVDF films on which PVDF microspheres were deposited with varying surface density. Maintenance of multipotentiality when cultured in expansion medium was studied by flow cytometry monitoring the expression of characteristic hMSCs markers, and revealed that cells were losing their characteristic surface markers on these supports. Cell morphology was assessed by scanning electron microscopy (SEM). Alkaline phosphatase activity was also assessed after seven days of culture on expansion medium. On the other hand, osteoblastic differentiation was monitored while culturing in osteogenic medium after cells reached confluence. Osteocalcin immunocytochemistry and alizarin red assays were performed. We show that flow cytometry is a suitable technique for the study of the differentiation of hMSC seeded onto biomaterials, giving a quantitative reliable analysis of hMSC-associated markers. We also show that electrosprayed piezoelectric poly(vinylidene fluoride) is a suitable support for tissue engineering purposes, as hMSCs can proliferate, be viable and undergo osteogenic differentiation when chemically stimulated. ; The authors thank the Portuguese Foundation for Science and Technology (FCT) for financial support under project PTDC/EEI-SII/5582/2014, Strategic Funding UID/FIS/04650/2013 and grants SFRH/BPD/90870/2012 (C.R.) and SFRH/BPD/121526/2016 (D.M.C). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK program. JLGR, LC, RSS and AS acknowledge funding by the Conselleria de Educación, Investigación, Cultura y Deporte of the Generalitat Valenciana through ...

"Version of Record online: 29 OCT 2015" ; Bone formation relies on complex processes that require well-orchestrated interactions between several cell types, such as bone-forming cells (osteoblasts, OBs) and endothelial cells (ECs). Their co-culture has been proved relevant to mimicking specific features of the bone niche. Here we propose the co-culture of microvascular-like ECs and pre-OBs, both derived from the SSEA-4+ cell subpopulation from the stromal vascular fraction of human adipose tissue (SSEA-4+ hASCs), to define the conditions in which cells synergistically communicate to support the full differentiation of pre-OBs and maintenance of the EC phenotype. Co-cultures of different ratios of the two cell types were established and maintained for up to 21 days in standard endothelial maintenance (ENDO) and osteogenic differentiation (OST) media, as well as in a mixture of these (MIX). The osteogenic maturation of pre-OBs (ALP activity, OPN and OCN expression, calcium deposition), the evolution of EC numbers (CD31+ cells) and maintenance of the endothelial phenotype (CD31 and vWF expression, LDL uptake) were assessed throughout the culture time as a function of cell ratio and culture media. The results obtained demonstrate that EC number has a significant effect on the osteogenic differentiation of pre-OBs, depending on the medium used. While in ENDO medium the osteogenic differentiation was not observed, in the OST and MIX media it was attained at similar levels, except for the co-culture with a higher number of ECs in MIX medium. These findings demonstrate that the use of SSEA-4+ hASCs as a single-cell source is promising to attain 3D bone-like models with the potential to promote vascularized bone tissue regeneration. ; The authors are grateful to the Portuguese Foundation for Science and Technology (FCT) for personal grants SFRH/BD/ 42968/2008 through the MIT–Portugal Programme (SMM). The research leading to these results has received funding from the MIT/ECE/0047/2009 project, the European Union Seventh ...

There is an increasing interest in developing novel macromolecular vehicles for the intracellular and controlled delivery of bioactive molecules, since they can allow modulation of the cellular functions in a more effective manner ex vivo, and maintain the cellular phenotype in vivo upon re-implantation. The present study was designed to investigate the effect of combining novel dexamethasone-loaded carboxymethylchitosan/ poly(amidoamine) dendrimer (Dex-loaded CMCht/PAMAM) nanoparticles and, both HA and SPCL scaffolds (3D system) on the proliferation and osteogenic differentiation of rat bone marrow stromal cells (RBMSCs) in vitro. A luminescent cell viability assay using RBMSCs was performed for screening cytotoxicity of the developed HA and SPCL scaffolds. Results corroborated previous ones which have demonstrated in vitro, the superior performance of the HA and SPCL scaffolds on supporting cells adhesion and proliferation. Furthermore, this work showed that RBMSCs seeded onto the surface of both HA and SPCL scaffolds differentiate into osteoblasts when cultured in the presence of 0.01 mg ml!1 Dexloaded CMCht/PAMAM dendrimer nanoparticles. In addition, results demonstrated that Dex-loaded CMCht/PAMAM dendrimer nanoparticles combined with the HA enhance osteogenesis by increasing ALP activity and mineralization of the extra-cellular matrix. The pre-incubation of stem cells with these kinds of nanoparticles allows the delivery of Dex inside the cells and directly influences their cellular fate, being a promising new tool to be used in cells and tissue engineering strategies. ; The authors thank the funds provided by Portuguese Foundation for Science and Technology (FCT) through POCTI and FEDER programmes including project ProteoLight (PTDC/FIS/68517/2006). This work was also carried out with the support of the European Union funded STREP Project HIPPOCRATES (NMP3-CF-2003-505758) and European NOE EXPERTISSUES (NMP3-CT-2004-500283). The funding provided by Canon Foundation in Europe is gratefully ...

Electrical stimulation (ES) has potential to be an effective tool for bone injury treatment in clinics. However, the therapeutic mechanism associated with ES is still being discussed. This study aims to investigate the initial mechanism of action by characterising the physical and chemical changes in the extracellular environment during ES and correlate them with the responses of mesenchymal stem/stromal cells (MSCs). Computational modelling was used to estimate the electrical potentials relative to the cathode and the current density across the cell monolayer. We showed expression of phosphorylated ERK1/2, c-FOS, c-JUN, and SPP1 mRNAs, as well as the increased metabolic activities of MSCs at different time points. Moreover, the average of 2.5 μM of HO and 34 μg/L of dissolved Pt were measured from the electrically stimulated media (ES media), which also corresponded with the increases in SPP1 mRNA expression and cell metabolic activities. The addition of sodium pyruvate to the ES media as an antioxidant did not alter the SPP1 mRNA expression, but eliminated an increase in cell metabolic activities induced by ES media treatment. These findings suggest that HO was influencing cell metabolic activity, whereas SPP1 mRNA expression was regulated by other faradic by-products. This study reveals how different electrical stimulation regime alters cellular regenerative responses and the roles of faradic by-products, that might be used as a physical tool to guide and control cell behaviour. ; BBSRC grant (BB/M013545/1). It also receives funding from The Royal Thai Government Scholarship (ST 4729) and Rosetrees Trust (M484