Colonization of bone matrices by cellular components

NASA Astrophysics Data System (ADS)

Shchelkunova, E. I.; Voropaeva, A. A.; Korel, A. V.; Mayer, D. A.; Podorognaya, V. T.; Kirilova, I. A.

2017-09-01

Practical surgery, traumatology, orthopedics, and oncology require bioengineered constructs suitable for replacement of large-area bone defects. Only rigid/elastic matrix containing recipient's bone cells capable of mitosis, differentiation, and synthesizing extracellular matrix that supports cell viability can comply with these requirements. Therefore, the development of the techniques to produce structural and functional substitutes, whose three-dimensional structure corresponds to the recipient's damaged tissues, is the main objective of tissue engineering. This is achieved by developing tissue-engineering constructs represented by cells placed on the matrices. Low effectiveness of carrier matrix colonization with cells and their uneven distribution is one of the major problems in cell culture on various matrixes. In vitro studies of the interactions between cells and material, as well as the development of new techniques for scaffold colonization by cellular components are required to solve this problem.

Design and characterization of a composite material based on Sr(II)-loaded clay nanotubes included within a biopolymer matrix.

PubMed

Del Buffa, Stefano; Bonini, Massimo; Ridi, Francesca; Severi, Mirko; Losi, Paola; Volpi, Silvia; Al Kayal, Tamer; Soldani, Giorgio; Baglioni, Piero

2015-06-15

This paper reports on the preparation, characterization, and cytotoxicity of a hybrid nanocomposite material made of Sr(II)-loaded Halloysite nanotubes included within a biopolymer (3-polyhydroxybutyrate-co-3-hydroxyvalerate) matrix. The Sr(II)-loaded inorganic scaffold is intended to provide mechanical resistance, multi-scale porosity, and to favor the in-situ regeneration of bone tissue thanks to its biocompatibility and bioactivity. The interaction of the hybrid system with the physiological environment is mediated by the biopolymer coating, which acts as a binder, as well as a diffusional barrier to the Sr(II) release. The degradation of the polymer progressively leads to the exposure of the Sr(II)-loaded Halloysite scaffold, tuning its interaction with osteogenic cells. The in vitro biocompatibility of the composite was demonstrated by cytotoxicity tests on L929 fibroblast cells. The results indicate that this composite material could be of interest for multiple strategies in the field of bone tissue engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

Current progress in bioactive ceramic scaffolds for bone repair and regeneration.

PubMed

Gao, Chengde; Deng, Youwen; Feng, Pei; Mao, Zhongzheng; Li, Pengjian; Yang, Bo; Deng, Junjie; Cao, Yiyuan; Shuai, Cijun; Peng, Shuping

2014-03-18

Bioactive ceramics have received great attention in the past decades owing to their success in stimulating cell proliferation, differentiation and bone tissue regeneration. They can react and form chemical bonds with cells and tissues in human body. This paper provides a comprehensive review of the application of bioactive ceramics for bone repair and regeneration. The review systematically summarizes the types and characters of bioactive ceramics, the fabrication methods for nanostructure and hierarchically porous structure, typical toughness methods for ceramic scaffold and corresponding mechanisms such as fiber toughness, whisker toughness and particle toughness. Moreover, greater insights into the mechanisms of interaction between ceramics and cells are provided, as well as the development of ceramic-based composite materials. The development and challenges of bioactive ceramics are also discussed from the perspective of bone repair and regeneration.

Current Progress in Bioactive Ceramic Scaffolds for Bone Repair and Regeneration

PubMed Central

Gao, Chengde; Deng, Youwen; Feng, Pei; Mao, Zhongzheng; Li, Pengjian; Yang, Bo; Deng, Junjie; Cao, Yiyuan; Shuai, Cijun; Peng, Shuping

2014-01-01

Bioactive ceramics have received great attention in the past decades owing to their success in stimulating cell proliferation, differentiation and bone tissue regeneration. They can react and form chemical bonds with cells and tissues in human body. This paper provides a comprehensive review of the application of bioactive ceramics for bone repair and regeneration. The review systematically summarizes the types and characters of bioactive ceramics, the fabrication methods for nanostructure and hierarchically porous structure, typical toughness methods for ceramic scaffold and corresponding mechanisms such as fiber toughness, whisker toughness and particle toughness. Moreover, greater insights into the mechanisms of interaction between ceramics and cells are provided, as well as the development of ceramic-based composite materials. The development and challenges of bioactive ceramics are also discussed from the perspective of bone repair and regeneration. PMID:24646912

Mesoporous bioactive glasses: structure characteristics, drug/growth factor delivery and bone regeneration application

PubMed Central

Wu, Chengtie; Chang, Jiang

2012-01-01

The impact of bone diseases and trauma in the whole world has increased significantly in the past decades. Bioactive glasses are regarded as an important bone regeneration material owing to their generally excellent osteoconductivity and osteostimulativity. A new class of bioactive glass, referred to as mesoporous bioglass (MBG), was developed 7 years ago, which possess a highly ordered mesoporous channel structure and a highly specific surface area. The study of MBG for drug/growth factor delivery and bone tissue engineering has grown significantly in the past several years. In this article, we review the recent advances of MBG materials, including the preparation of different forms of MBG, composition–structure relationship, efficient drug/growth factor delivery and bone tissue engineering application. By summarizing our recent research, the interaction of MBG scaffolds with bone-forming cells, the effect of drug/growth factor delivery on proliferation and differentiation of tissue cells and the in vivo osteogenesis of MBG scaffolds are highlighted. The advantages and limitations of MBG for drug delivery and bone tissue engineering have been compared with microsize bioactive glasses and nanosize bioactive glasses. The future perspective of MBG is discussed for bone regeneration application by combining drug delivery with bone tissue engineering and investigating the in vivo osteogenesis mechanism in large animal models. PMID:23741607

In vivo analysis of biocompatibility and vascularization of the synthetic bone grafting substitute NanoBone.

PubMed

Abshagen, K; Schrodi, I; Gerber, T; Vollmar, B

2009-11-01

One of the major challenges in the application of bone substitutes is adequate vascularization and biocompatibility of the implant. Thus, the temporal course of neovascularization and the microvascular inflammatory response of implants of NanoBone (fully synthetic nanocrystalline bone grafting material) were studied in vivo by using the mouse dorsal skinfold chamber model. Angiogenesis, microhemodynamics, and leukocyte-endothelial cell interaction were analyzed repetitively after implantation in the center and in the border zone of the implant up to 15 days. Both NanoBone granules and plates exhibited high biocompatibility comparable to that of cancellous bone, as indicated by a lack of venular leukocyte activation after implantation. In both synthetic NanoBone groups, signs of angiogenesis could be observed even at day 5 after implantation, whereas granules showed higher functional vessel density compared with NanoBone plates. The angiogenic response of the cancellous bone was markedly accelerated in the center of the implant tissue. Histologically, implant tissue showed an ingrowth of vascularized fibrous tissue into the material combined with an increased number of foreign-body giant cells. In conclusion, NanoBone, particularly in granular form, showed high biocompatibility and high angiogenic response, thus improving the healing of bone defects. Our results underline that, beside the composition and nanostructure, the macrostructure is also of importance for the incorporation of the biomaterial by the host tissue. (c) 2008 Wiley Periodicals, Inc.

Hierarchically engineered fibrous scaffolds for bone regeneration

PubMed Central

Sachot, Nadège; Castaño, Oscar; Mateos-Timoneda, Miguel A.; Engel, Elisabeth; Planell, Josep A.

2013-01-01

Surface properties of biomaterials play a major role in the governing of cell functionalities. It is well known that mechanical, chemical and nanotopographic cues, for example, influence cell proliferation and differentiation. Here, we present a novel coating protocol to produce hierarchically engineered fibrous scaffolds with tailorable surface characteristics, which mimic bone extracellular matrix. Based on the sol–gel method and a succession of surface treatments, hollow electrospun polylactic acid fibres were coated with a silicon–calcium–phosphate bioactive organic–inorganic glass. Compared with pure polymeric fibres that showed a completely smooth surface, the coated fibres exhibited a nanostructured topography and greater roughness. They also showed improved hydrophilic properties and a Young's modulus sixfold higher than non-coated ones, while remaining fully flexible and easy to handle. Rat mesenchymal stem cells cultured on these fibres showed great cellular spreading and interactions with the material. This protocol can be transferred to other structures and glasses, allowing the fabrication of various materials with well-defined features. This novel approach represents therefore a valuable improvement in the production of artificial matrices able to direct stem cell fate through physical and chemical interactions. PMID:23985738

Cell interactions in bone tissue engineering.

PubMed

Pirraco, R P; Marques, A P; Reis, R L

2010-01-01

Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and new bottom-up approaches are needed. The study of the cellular interactions between the cells relevant for bone biology can be of essential importance to that. In living bone, cells are in a context where communication with adjacent cells is almost permanent. Many fundamental works have been addressing these communications nonetheless, in a bone TE approach, the 3D perspective, being part of the microenvironment of a bone cell, is as crucial. Works combining the study of cell-to-cell interactions in a 3D environment are not as many as expected. Therefore, the bone TE field should not only gain knowledge from the field of fundamental Biology but also contribute for further understanding the biology of bone. In this review, a summary of the main works in the field of bone TE, aiming at studying cellular interactions in a 3D environment, and how they contributed towards the development of a functional engineered bone tissue, is presented.

Towards 4th generation biomaterials: a covalent hybrid polymer-ormoglass architecture

NASA Astrophysics Data System (ADS)

Sachot, N.; Mateos-Timoneda, M. A.; Planell, J. A.; Velders, A. H.; Lewandowska, M.; Engel, E.; Castaño, O.

2015-09-01

Hybrid materials are being extensively investigated with the aim of mimicking the ECM microenvironment to develop effective solutions for bone tissue engineering. However, the common drawbacks of a hybrid material are the lack of interactions between the scaffold's constituents and the masking of its bioactive phase. Conventional hybrids often degrade in a non-homogeneous manner and the biological response is far from optimal. We have developed a novel material with strong interactions between constituents. The bioactive phase is directly exposed on its surface mimicking the structure of the ECM of bone. Here, polylactic acid electrospun fibers have been successfully and reproducibly coated with a bioactive organically modified glass (ormoglass, Si-Ca-P2 system) covalently. In comparison with the pure polymeric mats, the fibers obtained showed improved hydrophilicity and mechanical properties, bioactive ion release, exhibited a nanoroughness and enabled good cell adhesion and spreading after just one day of culture (rMSCs and rEPCs). The fibers were coated with different ormoglass compositions to tailor their surface properties (roughness, stiffness, and morphology) by modifying the experimental parameters. Knowing that cells modulate their behavior according to the exposed physical and chemical signals, the development of this instructive material is a valuable advance in the design of functional regenerative biomaterials.Hybrid materials are being extensively investigated with the aim of mimicking the ECM microenvironment to develop effective solutions for bone tissue engineering. However, the common drawbacks of a hybrid material are the lack of interactions between the scaffold's constituents and the masking of its bioactive phase. Conventional hybrids often degrade in a non-homogeneous manner and the biological response is far from optimal. We have developed a novel material with strong interactions between constituents. The bioactive phase is directly exposed on its surface mimicking the structure of the ECM of bone. Here, polylactic acid electrospun fibers have been successfully and reproducibly coated with a bioactive organically modified glass (ormoglass, Si-Ca-P2 system) covalently. In comparison with the pure polymeric mats, the fibers obtained showed improved hydrophilicity and mechanical properties, bioactive ion release, exhibited a nanoroughness and enabled good cell adhesion and spreading after just one day of culture (rMSCs and rEPCs). The fibers were coated with different ormoglass compositions to tailor their surface properties (roughness, stiffness, and morphology) by modifying the experimental parameters. Knowing that cells modulate their behavior according to the exposed physical and chemical signals, the development of this instructive material is a valuable advance in the design of functional regenerative biomaterials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04275e

Osteoimmunology: Influence of the Immune System on Bone Regeneration and Consumption.

PubMed

Limmer, Andreas; Wirtz, Dieter C

2017-06-01

Background Stimulating bone regeneration is a central aim in orthopaedic and trauma surgery. Although the replacement of bone with artificial materials like cement or apatite helps to keep up bone stability, new bone often cannot be regenerated. Increasing research efforts have led to the clinical application of growth factors stimulating bone growth (e.g. bone morphogenic protein, BMP) and inhibitors preventing bone consumption (e.g. RANKL blocking antibodies). These factors mostly concentrate on stimulating osteoblast or preventing osteoclast activity. Current Situation It is widely accepted that osteoblasts and osteoclasts are central players in bone regeneration. This concept assumes that osteoblasts are responsible for bone growth while osteoclasts cause bone consumption by secreting matrix-degrading enzymes such as cathepsin K and matrix metalloproteinases (MMP). However, according to new research results, bone growth or consumption are not regulated by single cell types. It is rather the interaction of various cell types that regulates bone metabolism. While factors secreted by osteoblasts are essential for osteoclast differentiation and activation, factors secreted by activated osteoclasts are essential for osteoblast activity. In addition, recent research results imply that the influence of the immune system on bone metabolism has long been neglected. Factors secreted by macrophages or T cells strongly influence bone growth or degradation, depending on the bone microenvironment. Infections, sterile inflammation or tumour metastases not only affect bone cells directly, but also influence immune cells such as T cells indirectly. Furthermore, immune cells and bone are mechanistically regulated by similar factors such as cytokines, chemokines and transcription factors, suggesting that the definition of bone and immune cells has to be thought over. Outlook Bone and the immune system are regulated by similar mechanisms. These newly identified similarities between bone and the immune system imply that medication developed for tumour and autoimmune patients could also be applied in bone diseases. Georg Thieme Verlag KG Stuttgart · New York.

A Bone-Implant Interaction Mouse Model for Evaluating Molecular Mechanism of Biomaterials/Bone Interaction.

PubMed

Liu, Wenlong; Dan, Xiuli; Wang, Ting; Lu, William W; Pan, Haobo

2016-11-01

The development of an optimal animal model that could provide fast assessments of the interaction between bone and orthopedic implants is essential for both preclinical and theoretical researches in the design of novel biomaterials. Compared with other animal models, mice have superiority in accessing the well-developed transgenic modification techniques (e.g., cell tracing, knockoff, knockin, and so on), which serve as powerful tools in studying molecular mechanisms. In this study, we introduced the establishment of a mouse model, which was specifically tailored for the assessment of bone-implant interaction in a load-bearing bone marrow microenvironment and could potentially allow the molecular mechanism study of biomaterials by using transgenic technologies. The detailed microsurgery procedures for developing a bone defect (Φ = 0.8 mm) at the metaphysis region of the mouse femur were recorded. According to our results, the osteoconductive and osseointegrative properties of a well-studied 45S5 bioactive glass were confirmed by utilizing our mouse model, verifying the reliability of this model. The feasibility and reliability of the present model were further checked by using other materials as objects of study. Furthermore, our results indicated that this animal model provided a more homogeneous tissue-implant interacting surface than the rat at the early stage of implantation and this is quite meaningful for conducting quantitative analysis. The availability of transgenic techniques to mechanism study of biomaterials was further testified by establishing our model on Nestin-GFP transgenic mice. Intriguingly, the distribution of Nestin + cells was demonstrated to be recruited to the surface of 45S5 glass as early as 3 days postsurgery, indicating that Nestin + lineage stem cells may participate in the subsequent regeneration process. In summary, the bone-implant interaction mouse model could serve as a potential candidate to evaluate the early stage tissue response near the implant surface in a bone marrow microenvironment, and it also shows great potential in making transgenic animal resource applicable to biomaterial studies, so that the design of novel biomaterials could be better guided.

Nanoceramics on osteoblast proliferation and differentiation in bone tissue engineering.

PubMed

Sethu, Sai Nievethitha; Namashivayam, Subhapradha; Devendran, Saravanan; Nagarajan, Selvamurugan; Tsai, Wei-Bor; Narashiman, Srinivasan; Ramachandran, Murugesan; Ambigapathi, Moorthi

2017-05-01

Bone, a highly dynamic connective tissue, consist of a bioorganic phase comprising osteogenic cells and proteins which lies over an inorganic phase predominantly made of CaPO 4 (biological apatite). Injury to bone can be due to mechanical, metabolic or inflammatory agents also owing pathological conditions like fractures, osteomyelitis, osteolysis or cysts may arise in enameloid, chondroid, cementum, or chondroid bone which forms the intermediate tissues of the body. Bone tissue engineering (BTE) applies bioactive scaffolds, host cells and osteogenic signals for restoring damaged or diseased tissues. Various bioceramics used in BTE can be bioactive (like glass ceramics and hydroxyapatite bioactive glass), bioresorbable (like tricalcium phosphates) or bioinert (like zirconia and alumina). Limiting the size of these materials to nano-scale has resulted in a higher surface area to volume ratio thereby improving multi-functionality, solubility, surface catalytic activity, high heat and electrical conductivity. Nanoceramics have been found to induce osteoconduction, osteointegration, osteogenesis and osteoinduction. The present review aims at summarizing the interactions of nanoceramics and osteoblast/stem cells for promoting the proliferation and differentiation of the osteoblast cells by nanoceramics as superior bone substitutes in bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Plasma of argon enhances the adhesion of murine osteoblasts on different graft materials.

PubMed

Canullo, Luigi; Genova, Tullio; Naenni, Nadja; Nakajima, Yasushi; Masuda, Katsuhiko; Mussano, Federico

2018-04-25

plasma of argon treatment was demonstrated to increase material surface energy leading to stronger and faster interaction with cells. The aim of the present in vitro study was to test the effect of plasma treatment on different graft materials. synthetic hydroxyapatite (Mg-HA), biphasic calcium phosphate (BCP), cancellous and cortical xenogeneic bone matrices (CaBM, CoBM) were used representing commonly used classes of bone substitute materials. Fifty serially numbered disks with a 10mm-diameter from each graft material were randomly divided into two groups: Test group (argon plasma treatment) and Control group (absence of treatment). Cell morphology (using pre-osteoblastic murine cells) and protein adsorption were analyzed at all samples from both the test and control group. Differences between groups were analyzed using the Mann-Whitney test setting the level of significance at p<0.05. plasma treatment significantly increased the protein adsorption at all samples. Similarly, plasma treatment significantly increased cell adhesion in all groups. data confirmed that non-atmospheric plasma of argon treatment led to an increase of protein adsorption and cell adhesion in all groups of graft material to a similar extent. plasma of argon is able to improve the surface conditions of graft materials. Copyright © 2018 Elsevier GmbH. All rights reserved.

Nanotopographical control of human osteoprogenitor differentiation.

PubMed

Dalby, Matthew J; Gadegaard, Nikolaj; Curtis, Adam S G; Oreffo, Richard O C

2007-05-01

Current load-bearing orthopaedic implants are produced in 'bio-inert' materials such as titanium alloys. When inserted into the reamed bone during hip or knee replacement surgery the implants interact with mesenchymal populations including the bone marrow. Bio-inert materials are shielded from the body by differentiation of the cells along the fibroblastic lineage producing scar tissue and inferior healing. This is exacerbated by implant micromotion, which can lead to capsule formation. Thus, next-generation implant materials will have to elicit influence over osteoprogenitor differentiation and mesenchymal populations in order to recruit osteoblastic cells and produce direct bone apposition onto the implant. A powerful method of delivering cues to cells is via topography. Micro-scale topography has been shown to affect cell adhesion, migration, cytoskeleton, proliferation and differentiation of a large range of cell types (thus far all cell types tested have been shown to be responsive to topographical cues). More recent research with nanotopography has also shown a broad range of cell response, with fibroblastic cells sensing down to 10 nm in height. Initial studies with human mesenchymal populations and osteoprogenitor populations have again shown strong cell responses to nanofeatures with increased levels of osteocalcin and osteopontin production from the cells on certain topographies. This is indicative of increased osteoblastic activity on the nanotextured materials. Looking at preliminary data, it is tempting to speculate that progenitor cells are, in fact, more responsive to topography than more mature cell types and that they are actively seeking cues from their environment. This review will investigate the range of nanotopographies available to researchers and our present understanding of mechanisms of progenitor cell response. Finally, it will make some speculations of the future of nanomaterials and progenitor cells in tissue engineering.

3D silicon doped hydroxyapatite scaffolds decorated with Elastin-like Recombinamers for bone regenerative medicine.

PubMed

Vila, Mercedes; García, Ana; Girotti, Alessandra; Alonso, Matilde; Rodríguez-Cabello, Jose Carlos; González-Vázquez, Arlyng; Planell, Josep A; Engel, Elisabeth; Buján, Julia; García-Honduvilla, Natalio; Vallet-Regí, María

2016-11-01

The current study reports on the manufacturing by rapid prototyping technique of three-dimensional (3D) scaffolds based on silicon substituted hydroxyapatite with Elastin-like Recombinamers (ELRs) functionalized surfaces. Silicon doped hydroxyapatite (Si-HA), with Ca 10 (PO 4 ) 5.7 (SiO 4 ) 0.3 (OH) 1.7 h 0.3 nominal formula, was surface functionalized with two different types of polymers designed by genetic engineering: ELR-RGD that contain cell attachment specific sequences and ELR-SN A 15/RGD with both hydroxyapatite and cells domains that interact with the inorganic phase and with the cells, respectively. These hybrid materials were subjected to in vitro assays in order to clarify if the ELRs coating improved the well-known biocompatible and bone regeneration properties of calcium phosphates materials. The in vitro tests showed that there was a total and homogeneous colonization of the 3D scaffolds by Bone marrow Mesenchymal Stromal Cells (BMSCs). In addition, the BMSCs were viable and able to proliferate and differentiate into osteoblasts. Bone tissue engineering is an area of increasing interest because its main applications are directly related to the rising life expectancy of the population, which promotes higher rates of several bone pathologies, so innovative strategies are needed for bone tissue regeneration therapies. Here we use the rapid prototyping technology to allow moulding ceramic 3D scaffolds and we use different bio-polymers for the functionalization of their surfaces in order to enhance the biological response. Combining the ceramic material (silicon doped hydroxyapatite, Si-HA) and the Elastin like Recombinamers (ELRs) polymers with the presence of the integrin-mediate adhesion domain alone or in combination with SNA15 peptide that possess high affinity for hydroxyapatite, provided an improved Bone marrow Mesenchymal Stromal Cells (BMSCs) differentiation into osteoblastic linkage. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

T-cell acute leukaemia exhibits dynamic interactions with bone marrow microenvironments.

PubMed

Hawkins, Edwin D; Duarte, Delfim; Akinduro, Olufolake; Khorshed, Reema A; Passaro, Diana; Nowicka, Malgorzata; Straszkowski, Lenny; Scott, Mark K; Rothery, Steve; Ruivo, Nicola; Foster, Katie; Waibel, Michaela; Johnstone, Ricky W; Harrison, Simon J; Westerman, David A; Quach, Hang; Gribben, John; Robinson, Mark D; Purton, Louise E; Bonnet, Dominique; Lo Celso, Cristina

2016-10-27

It is widely accepted that complex interactions between cancer cells and their surrounding microenvironment contribute to disease development, chemo-resistance and disease relapse. In light of this observed interdependency, novel therapeutic interventions that target specific cancer stroma cell lineages and their interactions are being sought. Here we studied a mouse model of human T-cell acute lymphoblastic leukaemia (T-ALL) and used intravital microscopy to monitor the progression of disease within the bone marrow at both the tissue-wide and single-cell level over time, from bone marrow seeding to development/selection of chemo-resistance. We observed highly dynamic cellular interactions and promiscuous distribution of leukaemia cells that migrated across the bone marrow, without showing any preferential association with bone marrow sub-compartments. Unexpectedly, this behaviour was maintained throughout disease development, from the earliest bone marrow seeding to response and resistance to chemotherapy. Our results reveal that T-ALL cells do not depend on specific bone marrow microenvironments for propagation of disease, nor for the selection of chemo-resistant clones, suggesting that a stochastic mechanism underlies these processes. Yet, although T-ALL infiltration and progression are independent of the stroma, accumulated disease burden leads to rapid, selective remodelling of the endosteal space, resulting in a complete loss of mature osteoblastic cells while perivascular cells are maintained. This outcome leads to a shift in the balance of endogenous bone marrow stroma, towards a composition associated with less efficient haematopoietic stem cell function. This novel, dynamic analysis of T-ALL interactions with the bone marrow microenvironment in vivo, supported by evidence from human T-ALL samples, highlights that future therapeutic interventions should target the migration and promiscuous interactions of cancer cells with the surrounding microenvironment, rather than specific bone marrow stroma, to combat the invasion by and survival of chemo-resistant T-ALL cells.

Interaction between tumor cell surface receptor RAGE and proteinase 3 mediates prostate cancer metastasis to bone

PubMed Central

Kolonin, Mikhail G.; Sergeeva, Anna; Staquicini, Daniela I.; Smith, Tracey L.; Tarleton, Christy A.; Molldrem, Jeffrey J.; Sidman, Richard L.; Marchiò, Serena; Pasqualini, Renata; Arap, Wadih

2017-01-01

Human prostate cancer often metastasizes to bone, but the biological basis for such site-specific tropism remains largely unresolved. Recent work led us to hypothesize that this tropism may reflect pathogenic interactions between RAGE, a cell surface receptor expressed on malignant cells in advanced prostate cancer, and proteinase 3 (PR3), a serine protease present in inflammatory neutrophils and hematopoietic cells within the bone marrow microenvironment. In this study, we establish that RAGE-PR3 interaction mediates homing of prostate cancer cells to the bone marrow. PR3 bound to RAGE on the surface of prostate cancer cells in vitro, inducing tumor cell motility through a non-proteolytic signal transduction cascade involving activation and phosphorylation of ERK1/2 and JNK1. In preclinical models of experimental metastasis, ectopic expression of RAGE on human prostate cancer cells was sufficient to promote bone marrow homing within a short time frame. Our findings demonstrate how RAGE-PR3 interactions between human prostate cancer cells and the bone marrow microenvironment mediate bone metastasis during prostate cancer progression, with potential implications for prognosis and therapeutic intervention. PMID:28428279

Bone biomaterials and interactions with stem cells

PubMed Central

Gao, Chengde; Peng, Shuping; Feng, Pei; Shuai, Cijun

2017-01-01

Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive efforts have been devoted to developing bone biomaterials with a focus on the following issues: (1) developing ideal biomaterials with a combination of suitable biological and mechanical properties; (2) constructing a cell microenvironment with pores ranging in size from nanoscale to submicro- and microscale; and (3) inducing the oriented differentiation of stem cells for artificial-to-biological transformation. Here we present a comprehensive review of the state of the art of bone biomaterials and their interactions with stem cells. Typical bone biomaterials that have been developed, including bioactive ceramics, biodegradable polymers, and biodegradable metals, are reviewed, with an emphasis on their characteristics and applications. The necessary porous structure of bone biomaterials for the cell microenvironment is discussed, along with the corresponding fabrication methods. Additionally, the promising seed stem cells for bone repair are summarized, and their interaction mechanisms with bone biomaterials are discussed in detail. Special attention has been paid to the signaling pathways involved in the focal adhesion and osteogenic differentiation of stem cells on bone biomaterials. Finally, achievements regarding bone biomaterials are summarized, and future research directions are proposed. PMID:29285402

Bone microenvironment-mediated resistance of cancer cells to bisphosphonates and impact on bone osteocytes/stem cells.

PubMed

Alasmari, Abeer; Lin, Shih-Chun; Dibart, Serge; Salih, Erdjan

2016-08-01

Anti-resorptive bisphosphonates (BPs) have been clinically used to prevent cancer-bone metastasis and cancer-induced bone pathologies despite the fact that the phenotypic response of the cancer-bone interactions to BP exposure is "uncharted territory". This study offers unique insights into the interplay between cancer stem cells and osteocytes/osteoblasts and mesenchymal stem cells using a three-dimensional (3D) live cancer-bone interactive model. We provide extraordinary cryptic details of the biological events that occur as a result of alendronate (ALN) treatment using 3D live cancer-bone model systems under specific bone remodeling stages. While cancer cells are susceptible to BP treatment in the absence of bone, they are totally unaffected in the presence of bone. Cancer cells colonize live bone irrespective of whether the bone is committed to bone resorption or formation and hence, cancer-bone metastasis/interactions are though to be "independent of bone remodeling stages". In our 3D live bone model systems, ALN inhibited bone resorption at the osteoclast differentiation level through effects of mineral-bound ALN on osteocytes and osteoblasts. The mineral-bound ALN rendered bone incapable of osteoblast differentiation, while cancer cells colonize the bone with striking morphological adaptations which led to a conclusion that a direct anti-cancer effect of BPs in a "live or in vivo" bone microenvironment is implausible. The above studies were complemented with mass spectrometric analysis of the media from cancer-bone organ cultures in the absence and presence of ALN. The mineral-bound ALN impacts the bone organs by limiting transformation of mesenchymal stem cells to osteoblasts and leads to diminished endosteal cell population and degenerated osteocytes within the mineralized bone matrix.

TRAP-Positive Multinucleated Giant Cells Are Foreign Body Giant Cells Rather Than Osteoclasts: Results From a Split-Mouth Study in Humans.

PubMed

Lorenz, Jonas; Kubesch, Alica; Korzinskas, Tadas; Barbeck, Mike; Landes, Constantin; Sader, Robert A; Kirkpatrick, Charles J; Ghanaati, Shahram

2015-12-01

This study compared the material-specific tissue response to the synthetic, hydroxyapatite-based bone substitute material NanoBone (NB) with that of the xenogeneic, bovine-based bone substitute material Bio-Oss (BO). The sinus cavities of 14 human patients were augmented with NB and BO in a split-mouth design. Six months after augmentation, bone biopsies were extracted for histological and histomorphometric investigation prior to dental implant insertion. The following were evaluated: the cellular inflammatory pattern, the induction of multinucleated giant cells, vascularization, the relative amounts of newly formed bone, connective tissue, and the remaining bone substitute material. NB granules were well integrated in the peri-implant tissue and were surrounded by newly formed bone tissue. Multinucleated giant cells were visible on the surfaces of the remaining granules. BO granules were integrated into the newly formed bone tissue, which originated from active osteoblasts on their surface. Histomorphometric analysis showed a significantly higher number of multinucleated giant cells and blood vessels in the NB group compared to the BO group. No statistical differences were observed in regard to connective tissue, remaining bone substitute, and newly formed bone. The results of this study highlight the different cellular reactions to synthetic and xenogeneic bone substitute materials. The significantly higher number of multinucleated giant cells within the NB implantation bed seems to have no effect on its biodegradation. Accordingly, the multinucleated giant cells observed within the NB implantation bed have characteristics more similar to those of foreign body giant cells than to those of osteoclasts.

In vitro biological evaluation of beta-TCP/HDPE--A novel orthopedic composite: a survey using human osteoblast and fibroblast bone cells.

PubMed

Homaeigohar, S Sh; Shokrgozar, M A; Khavandi, A; Sadi, A Yari

2008-02-01

Beta-tricalcium phosphate reinforced high density polyethylene (beta-TCP/HDPE) was prepared to simulate bone composition and to study its capacity to act as bone tissue. This material was produced by replacing the mineral component and collagen soft tissue of the bone with beta-TCP and HDPE, respectively. The biocompatibility of the composite samples with different volume fractions of TCP (20, 30 and 40 vol %) was examined in vitro using two osteoblast cell lines G-292 and Saos-2, and also a type of fibroblast cell isolated from bone tissue, namely human bone fibroblast (HBF) by proliferation, and cell adhesion assays. Cell-material interaction with the surface of the composite samples was examined by scanning electron microscopy (SEM). The effect of beta-TCP/HDPE on the behavior of osteoblast and fibroblast cells was compared with those of composite and negative control samples; polyethylene (PE) and tissue culture polystyrene (TPS), respectively. In general, the results showed that the composite samples containing beta-TCP as reinforcement supported a higher rate of proliferation by various bone cells after 3, 7, and 14 days of incubation compared to the composite control sample. Furthermore, more osteoblast cells were attached to the surface of the composite samples when compared to the composite control samples after the above incubation periods (p < 0.05), while in the case of HBF an equal or even higher number of cells adhered to PE was observed. The number of adhered osteoblast cells was almost equal and in some days even higher than the number of adhered cells on negative control sample, while in the case of fibroblast this difference was significantly higher than TPS (p < 0.05). Adhered cells presented a normal morphology by SEM and many of the cells were observed to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and act to stimulate proliferation and adhesion of the cells, whether osteoblast or fibroblast. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

Bone cell-materials interaction on Si microchannels with bioinert coatings.

PubMed

Condie, Russell; Bose, Susmita; Bandyopadhyay, Amit

2007-07-01

Bone implant life is dependent upon integration of biomaterial surfaces with local osteoblasts. This investigation studied the effects of various microchannel parameters and surface chemistry on immortalized osteoblast precursor cell (OPC1) adhesion. Cell-materials interactions were observed within channels of varying length, width, tortuosity, convergence, divergence and chemistry. Si wafers were used to create four distinct 1cm(2) designs of varying channel dimensions. After anisotropic chemical etching to a depth of 120microm, wafers were sputter coated with gold and titanium; and on another surface SiO(2) was grown to vary the surface chemistry of these microchannels. OPC1 cells were seeded in the central cavity of each chip before incubation in tissue culture plates. On days 5, 11 and 16, samples were taken out, fixed and processed for microscopic analysis. Samples were visually characterized, qualitatively scored and analyzed. Channel walls did not contain OPC1 migration, but showed locally interrupted adhesion. Scores for channels of floor widths as narrow as 350microm were significantly reduced. No statistically significant preference was detected for gold, titanium or SiO(2) surfaces. Bands of OPC1 cells appeared to align with nearby channels, suggesting that cell morphology may be controlled by topography of the design to improve osseointegration.

ABL kinases promote breast cancer osteolytic metastasis by modulating tumor-bone interactions through TAZ and STAT5 signaling

PubMed Central

Wang, Jun; Rouse, Clay; Jasper, Jeff S.; Pendergast, Ann Marie

2016-01-01

Bone metastases occur in up to 70% of advanced breast cancer. For most patients with breast cancer, bone metastases are predominantly osteolytic. Interactions between tumor cells and stromal cells in the bone microenvironment drive osteolytic bone metastasis, a process that requires the activation of osteoclasts, cells that break down bone. Here, we report that ABL kinases promoted metastasis of breast cancer cells to bone by regulating the crosstalk between tumor and the bone microenvironment. ABL kinases protected tumor cells from apoptosis induced by TRAIL (TNF-related apoptosis-inducing ligand), activated the transcription factor STAT5, and promoted osteolysis through the STAT5-dependent expression of genes encoding the osteoclast activating factors interleukin 6 (IL6) and matrix metalloproteinase-1 (MMP1). Furthermore, ABL kinases increased the abundance of the Hippo pathway mediator TAZ and the expression of TAZ-dependent target genes that promote bone metastasis. Knockdown of ABL kinases or treatment with ABL-specific allosteric inhibitor impaired osteolytic metastasis of breast cancer cells in mice. These findings revealed a role for ABL kinases in regulating tumor-bone interactions and provide a rationale for targeting both tumor and the bone microenvironment with ABL-specific inhibitors. PMID:26838548

Biomaterials and bone mechanotransduction

NASA Technical Reports Server (NTRS)

Sikavitsas, V. I.; Temenoff, J. S.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

2001-01-01

Bone is an extremely complex tissue that provides many essential functions in the body. Bone tissue engineering holds great promise in providing strategies that will result in complete regeneration of bone and restoration of its function. Currently, such strategies include the transplantation of highly porous scaffolds seeded with cells. Prior to transplantation the seeded cells are cultured in vitro in order for the cells to proliferate, differentiate and generate extracellular matrix. Factors that can affect cellular function include the cell-biomaterial interaction, as well as the biochemical and the mechanical environment. To optimize culture conditions, good understanding of these parameters is necessary. The new developments in bone biology, bone cell mechanotransduction, and cell-surface interactions are reviewed here to demonstrate that bone mechanotransduction is strongly influenced by the biomaterial properties.

Characterizing the inorganic/organic interface in cancer bone metastasis

NASA Astrophysics Data System (ADS)

Wu, Fei

Bone metastasis frequently occurs in patients with advanced breast cancer and remains a major source of mortality. At the molecular level, bone is a nanocomposite composed of inorganic bone mineral deposited within an organic extracellular matrix (ECM). Although the exact mechanisms of bone metastasis remain unclear, the nanoscale materials properties of bone mineral have been implicated in this process. Bone apatite is closely related to synthetic hydroxyapatite (HAP, Ca10(PO4)6(OH)2) in terms of structural and mechanical properties. Additionally, although the primary protein content of bone is collagen I, the glycoprotein fibronectin (Fn) is essential in maintaining the overall integrity of the bone matrix. Importantly, in vivo, neither breast cancer cells nor normal bone cells interact directly with the bone mineral but rather with the protein film adsorbed onto the mineral surface. Therefore, we hypothesized that breast cancer cell functions were regulated by differential fibronectin adsorption onto hydroxyapatite, which led to pathological remodeling of the bone matrix and sustained bone metastasis. Three model systems containing HAP and Fn were developed for this thesis. In model system I, a library of synthetic HAP nanoparticles were utilized to investigate the effect of mineral size, shape, and crystallinity on Fn conformation, using Forster resonance energy transfer (FRET) spectroscopy. In model system II, Fn-functionalized large geologic HAP crystals were used instead of HAP nanoparticles to avoid cellular uptake when investigating subsequent cell functions. Overall our FRET analysis (models I and II) revealed that Fn conformation depended on size, surface chemistry, and roughness of underlying HAP. When breast cancer cells were seeded on the Fn-coated HAP crystal facets (model II), our data indicated high secretion levels of proangiogenic and proinflammatory factors associated with the presence of unfolded Fn conformations, likely caused by differential engagement of cell receptors integrins with the underlying Fn. Finally, in model system III, Fn fibrillar structures (mimicking the bone matrix) were fabricated and characterized in presence of HAP nanoparticles, suggesting that the presence of microcalcifications found in tumorous/inflammed tissues affects both the structural and mechanical properties of the surrounding ECM. Collectively, our study of cellular behavior regulated by mineral/ECM interactions provides insights into the pathogenesis of breast cancer bone metastasis as well as other HAP-related inflammation.

[Encounter of cancer cells with bone. Histological examination of bone metastasis].

PubMed

Kanda, Hiroaki

2011-03-01

Management of the cancer bone metastasis is important clinical problem. The mechanism (s) of bone metastasis has been studied mainly by animal models and in vitro system. There might be discrepancy between model systems and in vivo human clinical materials. But there is surprisingly rare study of histological examination of human skeletal metastasis, since it is hard to obtain human materials without modification by chemotherapy or irradiation. There are many surgical materials suitable for this examination in our hospital and we have been examined histological features of them. Stromal cells between metastatic cancer cells and OCs (osteoclasts) and÷or OBs (osteoblasts) might play a role in bone metastasis, since these cells are frequently accompanied with OCs÷OBs. We called these stromal cells as "fibroblast-like cells" and examined their nature and roles in bone metastasis. We hope these fibroblast-like cells might become the target of anti bone metastasis therapy, same as osteoclasts targeted by bisphosphonates.

Polyelectrolyte multi-layers assembly of SiCHA nanopowders and collagen type I on aminolysed PLA films to enhance cell-material interactions.

PubMed

Baba Ismail, Yanny Marliana; Ferreira, Ana Marina; Bretcanu, Oana; Dalgarno, Kenneth; El Haj, Alicia J

2017-11-01

This paper presents a new approach in assembling bone extracellular matrix components onto PLA films, and investigates the most favourable environment which can be created using the technique for cell-material interactions. Poly (lactic acid) (PLA) films were chemically modified by covalently binding the poly(ethylene imine) (PEI) as to prepare the substrate for immobilization of polyelectrolyte multilayers (PEMs) coating. Negatively charged polyelectrolyte consists of well-dispersed silicon-carbonated hydroxyapatite (SiCHA) nanopowders in hyaluronic acid (Hya) was deposited onto the modified PLA films followed by SiCHA in collagen type I as the positively charged polyelectrolyte. The outermost layer was finally cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrocholoride and N-hydroxysulfosuccinimide sodium salt (EDC/NHS) solutions. The physicochemical features of the coated PLA films were monitored via X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscope (AFM). The amounts of calcium and collagen deposited on the surface were qualitatively and quantitatively determined. The surface characterizations suggested that 5-BL has the optimum surface roughness and highest amounts of calcium and collagen depositions among tested films. In vitro human mesenchymal stem cells (hMSCs) cultured on the coated PLA films confirmed that the coating materials greatly improved cell attachment and survival compared to unmodified PLA films. The cell viability, cell proliferation and Alkaline Phosphatase (ALP) expression on 5-BL were found to be the most favourable of the tested films. Hence, this newly developed coating materials assembly could contribute to the improvement of the bioactivity of polymeric materials and structures aimed to bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Pediatric precursor B acute lymphoblastic leukemia: are T helper cells the missing link in the infectious etiology theory?

PubMed

Bürgler, Simone; Nadal, David

2017-12-01

Precursor B acute lymphoblastic leukemia (BCP-ALL), the most common childhood malignancy, arises from an expansion of malignant B cell precursors in the bone marrow. Epidemiological studies suggest that infections or immune responses to infections may promote such an expansion and thus BCP-ALL development. Nevertheless, a specific pathogen responsible for this process has not been identified. BCP-ALL cells critically depend on interactions with the bone marrow microenvironment. The bone marrow is also home to memory T helper (Th) cells that have previously expanded during an immune response in the periphery. In secondary lymphoid organs, Th cells can interact with malignant cells of mature B cell origin, while such interactions between Th cells and malignant immature B cell in the bone marrow have not been described yet. Nevertheless, literature supports a model where Th cells-expanded during an infection in early childhood-migrate to the bone marrow and support BCP-ALL cells as they support normal B cells. Further research is required to mechanistically confirm this model and to elucidate the interaction pathways between leukemia cells and cells of the tumor microenvironment. As benefit, targeting these interactions could be included in current treatment regimens to increase therapeutic efficiency and to reduce relapses.

Cellular compatibility of highly degradable bioactive ceramics for coating of metal implants.

PubMed

Radetzki, F; Wohlrab, D; Zeh, A; Delank, K S; Mendel, T; Berger, G; Syrowatka, F; Mayr, O; Bernstein, A

2011-01-01

Resorbable ceramics can promote the bony integration of implants. Their rate of degradation should ideally be synchronized with bone regeneration. This study examined the effect of rapidly resorbable calcium phosphate ceramics 602020, GB14, 305020 on adherence, proliferation and morphology of human bone-derived cells (HBDC) in comparison to β-TCP. The in vitro cytotoxicity was determined by the microculture tetrazolium (MTT) assay. HBDC were grown on the materials for 3, 7, 11, 15 and 19 days and counted. Cell morphology, cell attachment, cell spreading and the cytoskeletal organization of HBDC cultivated on the substrates were investigated using laser scanning microscopy and environmental scanning electron microscopy. All substrates supported sufficient cellular growth for 19 days and showed no cytotoxicity. On each material an identical cell colonisation of well communicating, polygonal, vital cells with strong focal contacts was verified. HBDC showed numerous well defined stress fibres which give proof of well spread and strongly anchored cells. Porous surfaces encouraged the attachment and spreading of HBDC. Further investigations regarding long term biomaterial/cell interactions in vitro and in vivo are required to confirm the utility of the new biomaterials.

Osteoblasts Interaction with PLGA Membranes Functionalized with Titanium Film Nanolayer by PECVD. In vitro Assessment of Surface Influence on Cell Adhesion during Initial Cell to Material Interaction

PubMed Central

Terriza, Antonia; Vilches-Pérez, José I.; González-Caballero, Juan L.; de la Orden, Emilio; Yubero, Francisco; Barranco, Angel; Gonzalez-Elipe, Agustín R.; Vilches, José; Salido, Mercedes

2014-01-01

New biomaterials for Guided Bone Regeneration (GBR), both resorbable and non-resorbable, are being developed to stimulate bone tissue formation. Thus, the in vitro study of cell behavior towards material surface properties turns a prerequisite to assess both biocompatibility and bioactivity of any material intended to be used for clinical purposes. For this purpose, we have developed in vitro studies on normal human osteoblasts (HOB®) HOB® osteoblasts grown on a resorbable Poly (lactide-co-glycolide) (PLGA) membrane foil functionalized by a very thin film (around 15 nm) of TiO2 (i.e., TiO2/PLGA membranes), designed to be used as barrier membrane. To avoid any alteration of the membranes, the titanium films were deposited at room temperature in one step by plasma enhanced chemical vapour deposition. Characterization of the functionalized membranes proved that the thin titanium layer completely covers the PLGA foils that remains practically unmodified in their interior after the deposition process and stands the standard sterilization protocols. Both morphological changes and cytoskeletal reorganization, together with the focal adhesion development observed in HOB osteoblasts, significantly related to TiO2 treated PLGA in which the Ti deposition method described has revealed to be a valuable tool to increase bioactivity of PLGA membranes, by combining cell nanotopography cues with the incorporation of bioactive factors. PMID:28788538

Stem cell-mediated osteogenesis: therapeutic potential for bone tissue engineering

PubMed Central

Neman, Josh; Hambrecht, Amanda; Cadry, Cherie; Jandial, Rahul

2012-01-01

Intervertebral disc degeneration often requires bony spinal fusion for long-term relief. Current arthrodesis procedures use bone grafts from autogenous bone, allogenic backed bone, or synthetic materials. Autogenous bone grafts can result in donor site morbidity and pain at the donor site, while allogenic backed bone and synthetic materials have variable effectiveness. Given these limitations, researchers have focused on new treatments that will allow for safe and successful bone repair and regeneration. Mesenchymal stem cells have received attention for their ability to differentiate into osteoblasts, cells that synthesize new bone. With the recent advances in scaffold and biomaterial technology as well as stem cell manipulation and transplantation, stem cells and their scaffolds are uniquely positioned to bring about significant improvements in the treatment and outcomes of spinal fusion and other injuries. PMID:22500114

Stem cell-mediated osteogenesis: therapeutic potential for bone tissue engineering.

PubMed

Neman, Josh; Hambrecht, Amanda; Cadry, Cherie; Jandial, Rahul

2012-01-01

Intervertebral disc degeneration often requires bony spinal fusion for long-term relief. Current arthrodesis procedures use bone grafts from autogenous bone, allogenic backed bone, or synthetic materials. Autogenous bone grafts can result in donor site morbidity and pain at the donor site, while allogenic backed bone and synthetic materials have variable effectiveness. Given these limitations, researchers have focused on new treatments that will allow for safe and successful bone repair and regeneration. Mesenchymal stem cells have received attention for their ability to differentiate into osteoblasts, cells that synthesize new bone. With the recent advances in scaffold and biomaterial technology as well as stem cell manipulation and transplantation, stem cells and their scaffolds are uniquely positioned to bring about significant improvements in the treatment and outcomes of spinal fusion and other injuries.

[Histocompatibility of nano-hydroxyapatite/poly-co-glycolic acid tissue engineering bone modified by mesenchymal stem cells with vascular endothelial frowth factor].

PubMed

Zhang, Minglei; Wang, Dapeng; Yin, Ruofeng

2015-10-06

To explorec Histocompatibility of nano-hydroxyapatite/poly-co-glycolic acid tissue engineering bone modified by mesenchymal stem cells with vascular endothelial frowth factor transinfected. Rat bone marrow mesenchymal stem cells (BMSCs) was separated, using BMSCs as target cells, and then vascular endothelial growth factor (VEGF) gene was transfected. Composite bone marrow mesenchymal stem cells and cells transfected with nano-hydroxyapatite (HA)/polylactic-co-glycolic acid (PLGA). The composition of cell and scaffold was observed. The blank plasmid transfection was 39.1%, 40.1% in VEGF group. The cell adhesion and growth was found on the scaffold pore wall after 5 days, and the number of adherent cells in the nano-HA/PLGA composite scaffold material basically had no significant difference in both. Although the nano-HA/PLGA scaffold material is still not fully meet the requirements of the matrix material for bone tissue engineering, but good biocompatibility, structure is its rich microporous satisfaction in material mechanics, toughening, enhanced obviously. Composition scaffold with BMSCs transfected by VEGF plasmid, the ability of angiogenesis is promoted.

Biodegradation, biocompatibility, and osteoconduction evaluation of collagen-nanohydroxyapatite cryogels for bone tissue regeneration.

PubMed

Salgado, Christiane Laranjo; Grenho, Liliana; Fernandes, Maria Helena; Colaço, Bruno Jorge; Monteiro, Fernando Jorge

2016-01-01

Designing biomimetic biomaterials inspired by the natural complex structure of bone and other hard tissues is still a challenge nowadays. The control of the biomineralization process onto biomaterials should be evaluated before clinical application. Aiming at bone regeneration applications, this work evaluated the in vitro biodegradation and interaction between human bone marrow stromal cells (HBMSC) cultured on different collagen/nanohydroxyapatite cryogels. Cell proliferation, differentiation, morphology, and metabolic activity were assessed through different protocols. All the biocomposite materials allowed physiologic apatite deposition after incubation in simulated body fluid and the cryogel with the highest nanoHA content showed to have the highest mechanical strength (DMA). The study clearly showed that the highest concentration of nanoHA granules on the cryogels were able to support cell type's survival, proliferation, and individual functionality in a monoculture system, for 21 days. In fact, the biocomposites were also able to differentiate HBMSCs into osteoblastic phenotype. The composites behavior was also assessed in vivo through subcutaneous and bone implantation in rats to evaluate its tissue-forming ability and degradation rate. The cryogels Coll/nanoHA (30 : 70) promoted tissue regeneration and adverse reactions were not observed on subcutaneous and bone implants. The results achieved suggest that scaffolds of Coll/nanoHA (30 : 70) should be considered promising implants for bone defects that present a grotto like appearance with a relatively small access but a wider hollow inside. This material could adjust to small dimensions and when entering into the defect, it could expand inside and remain in close contact with the defect walls, thus ensuring adequate osteoconductivity. © 2015 Wiley Periodicals, Inc.

Comparative evaluation of different calcium phosphate-based bone graft granules - an in vitro study with osteoblast-like cells.

PubMed

Bernhardt, Anne; Lode, Anja; Peters, Fabian; Gelinsky, Michael

2013-04-01

Granule-shaped calcium phosphate-based bone graft materials are often required for bone regeneration especially in implant dentistry. Two newly developed bone graft materials are Ceracell(®) , an open-celled highly porous bioceramic from β-tricalcium phosphate (β-TCP) under addition of bioglass and Osseolive(®) , an open porous glass ceramic with the general formula Ca2 KNa(PO4 )2 . The goal of this study was to characterize different modifications of the two bone graft materials in vitro in comparison to already established ceramic bone grafts Cerasorb M(®) , NanoBone(®) and BONIT Matrix(®) . Adhesion and proliferation of SaOS-2 osteoblast-like cells were evaluated quantitatively by determining DNA content and lactate dehydrogenase (LDH) activity and qualitatively by scanning electron microscopy (SEM). In addition, MTT cell-vitality staining was applied to confirm the attachment of viable cells to the different materials. Osteogenic differentiation was evaluated by measurement of alkaline phosphatase (ALP) activity as well as gene expression analysis of osteogenic markers using reverse transcriptase PCR. DNA content and LDH activity revealed good cell attachment and proliferation for Ceracell and Cerasorb M. When pre-incubated with cell-culture medium, also Osseolive showed good cell attachment and proliferation. Attachment and proliferation of osteoblast-like cells on NanoBone and BONIT Matrix was very low, even after pre-incubation with cell-culture medium. Specific ALP activity on Ceracell(®) , Osseolive (®) and Cerasorb M(®) increased with time and expression of bone-related genes ALP, osteonectin, osteopontin and bone sialoprotein II was demonstrated. Ceracell as well as Osseolive granules support proliferation and osteogenic differentiation in vitro and may be promising candidates for in vivo applications. © 2011 John Wiley & Sons A/S.

Influence of nanostructural environment and fluid flow on osteoblast-like cell behavior: a model for cell-mechanics studies.

PubMed

Prodanov, L; Semeins, C M; van Loon, J J W A; te Riet, J; Jansen, J A; Klein-Nulend, J; Walboomers, X F

2013-05-01

Introducing nanoroughness on various biomaterials has been shown to profoundly effect cell-material interactions. Similarly, physical forces act on a diverse array of cells and tissues. Particularly in bone, the tissue experiences compressive or tensile forces resulting in fluid shear stress. The current study aimed to develop an experimental setup for bone cell behavior, combining a nanometrically grooved substrate (200 nm wide, 50 nm deep) mimicking the collagen fibrils of the extracellular matrix, with mechanical stimulation by pulsatile fluid flow (PFF). MC3T3-E1 osteoblast-like cells were assessed for morphology, expression of genes involved in cell attachment and osteoblastogenesis and nitric oxide (NO) release. The results showed that both nanotexture and PFF did affect cellular morphology. Cells aligned on nanotexture substrate in a direction parallel to the groove orientation. PFF at a magnitude of 0.7 Pa was sufficient to induce alignment of cells on a smooth surface in a direction perpendicular to the applied flow. When environmental cues texture and flow were interacting, PFF of 1.4 Pa applied parallel to the nanogrooves initiated significant cellular realignment. PFF increased NO synthesis 15-fold in cells attached to both smooth and nanotextured substrates. Increased collagen and alkaline phosphatase mRNA expression was observed on the nanotextured substrate, but not on the smooth substrate. Furthermore, vinculin and bone sialoprotein were up-regulated after 1 h of PFF stimulation. In conclusion, the data show that interstitial fluid forces and structural cues mimicking extracellular matrix contribute to the final bone cell morphology and behavior, which might have potential application in tissue engineering. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Study of TiO{sub 2} nanotubes as an implant application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazan, Roshasnorlyza, E-mail: roshasnorlyza@nm.gov.my; Sreekantan, Srimala; Mydin, Rabiatul Basria S. M. N.

Vertically aligned TiO{sub 2} nanotubes have become the primary candidates for implant materials that can provide direct control of cell behaviors. In this work, 65 nm inner diameters of TiO{sub 2} nanotubes were successfully prepared by anodization method. The interaction of bone marrow stromal cells (BMSC) in term of cell adhesion and cell morphology on bare titanium and TiO{sub 2} nanotubes is reported. Field emission scanning electron microscopy (FESEM) analysis proved interaction of BMSC on TiO{sub 2} nanotubes structure was better than flat titanium (Ti) surface. Also, significant cell adhesion on TiO{sub 2} nanotubes surface during in vitro study revealed thatmore » BMSC prone to attach on TiO{sub 2} nanotubes. From the result, it can be conclude that TiO{sub 2} nanotubes are biocompatible to biological environment and become a new generation for advanced implant materials.« less

Biocompatibility and osteoconduction of macroporous silk fibroin implants in cortical defects in sheep.

PubMed

Uebersax, Lorenz; Apfel, Tanja; Nuss, Katja M R; Vogt, Rainer; Kim, Hyoen Yoo; Meinel, Lorenz; Kaplan, David L; Auer, Joerg A; Merkle, Hans P; von Rechenberg, Brigitte

2013-09-01

The goal of the presented study was to compare the biocompatibility and cellular responses to porous silk fibroin (SF) scaffolds produced in a water-based (UPW) or a solvent based process (HFIP) using two different SF sources. For that reason, four different SF scaffolds were implanted (n=6) into drill hole defects in the cancellous bone of the sheep tibia and humerus. The scaffolds were evaluated histologically for biocompatibility, cell-material interaction, and cellular ingrowth. New bone formation was observed macroscopically and histologically at 8 weeks after implantation. For semiquantitative evaluation, the investigated parameters were scored and statistically analyzed (factorial ANOVA). All implants showed good biocompatibility as evident by low infiltration of inflammatory cells and the absent encapsulation of the scaffolds in connective tissue. Multinuclear foreign body giant cells (MFGCs) and macrophages were present in all parts of the scaffold at the material surface and actively degrading the SF material. Cell ingrowth and vascularization were uniform across the scaffold. However, in HFIP scaffolds, local regions of void pores were present throughout the scaffold, probably due to the low pore interconnectivity in this scaffold type in contrast to UPW scaffolds. The amount of newly formed bone was very low in both scaffold types but was more abundant in the periphery than in the center of the scaffolds and for HFIP scaffolds mainly restricted to single pores. Copyright © 2013 Elsevier B.V. All rights reserved.

A new iron calcium phosphate material to improve the osteoconductive properties of a biodegradable ceramic: a study in rabbit calvaria.

PubMed

Manchón, Angel; Hamdan Alkhraisat, Mohammad; Rueda-Rodriguez, Carmen; Prados-Frutos, Juan Carlos; Torres, Jesús; Lucas-Aparicio, Julia; Ewald, Andrea; Gbureck, Uwe; López-Cabarcos, Enrique

2015-10-20

β-tricalcium phosphate (β-TCP) is an osteoconductive and biodegradable material used in bone regeneration procedures, while iron has been suggested as a tool to improve the biological performance of calcium phosphate-based materials. However, the mechanisms of interaction between these materials and human cells are not fully understood. In order to clarify this relationship, we have studied the iron role in β-TCP ceramics. Iron-containing β-TCPs were prepared by replacing CaCO3 with C6H5FeO7 at different molar ratios. X-ray diffraction analysis indicated the occurrence of β-TCP as the sole phase in the pure β-TCP and iron-containing ceramics. The incorporation of iron ions in the β-TCP lattice decreased the specific surface area as the pore size was shifted toward meso- and/or macropores. Furthermore, the human osteoblastlike cell line MG-63 was cultured onto the ceramics to determine cell proliferation and viability, and it was observed that the iron-β-TCP ceramics have better cytocompatibility than pure β-TCP. Finally, in vivo assays were performed using rabbit calvaria as a bone model. The scaffolds were implanted for 8 and 12 weeks in the defects created in the skullcap with pure β-TCP as the control. The in vivo behavior, in terms of new bone formed, degradation, and residual graft material were investigated using sequential histological evaluations and histomorphometric analysis. The in vivo implantation of the ceramics showed enhanced bone tissue formation and scaffold degradation for iron-β-TCPs. Thus, iron appears to be a useful tool to enhance the osteoconductive properties of calcium phosphate ceramics.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction

PubMed Central

Shah, Nisarg J.; Hyder, Md. Nasim; Quadir, Mohiuddin A.; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J.; Nevins, Myron; Spector, Myron; Hammond, Paula T.

2014-01-01

Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration. PMID:25136093

The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone.

PubMed

Wang, Weiwei; Kratz, Karl; Behl, Marc; Yan, Wan; Liu, Yue; Xu, Xun; Baudis, Stefan; Li, Zhengdong; Kurtz, Andreas; Lendlein, Andreas; Ma, Nan

2015-01-01

Polyether ether ketone (PEEK) as a high-performance, thermoplastic implant material entered the field of medical applications due to its structural function and commercial availability. In bone tissue engineering, the combination of mesenchymal stem cells (MSCs) with PEEK implants may accelerate the bone formation and promote the osseointegration between the implant and the adjacent bone tissue. In this concept the question how PEEK influences the behaviour and functions of MSCs is of great interest. Here the cellular response of human adipose-derived MSCs to PEEK was evaluated and compared to tissue culture plate (TCP) as the reference material. Viability and morphology of cells were not altered when cultured on the PEEK film. The cells on PEEK presented a high proliferation activity in spite of a relatively lower initial cell adhesion rate. There was no significant difference on cell apoptosis and senescence between the cells on PEEK and TCP. The inflammatory cytokines and VEGF secreted by the cells on these two surfaces were at similar levels. The cells on PEEK showed up-regulated BMP2 and down-regulated BMP4 and BMP6 gene expression, whereas no conspicuous differences were observed in the committed osteoblast markers (BGLAP, COL1A1 and Runx2). With osteoinduction the cells on PEEK and TCP exhibited a similar osteogenic differentiation potential. Our results demonstrate the biofunctionality of PEEK for human MSC cultivation and differentiation. Its clinical benefits in bone tissue engineering may be achieved by combining MSCs with PEEK implants. These data may also provide useful information for further modification of PEEK with chemical or physical methods to regulate the cellular processes of MSCs and to consequently improve the efficacy of MSC-PEEK based therapies.

Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate bone substitute granules in caprine muscle tissue does not induce new bone formation

PubMed Central

2013-01-01

Background Osteoinductive bone substitutes are defined by their ability to induce new bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different bone substitute materials in caprine muscle tissue. Materials and methods One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO2)-based nanocrystalline bone substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized bone matrix. Results Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. Conclusions This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped bone substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting. PMID:23286366

Interconnected porosity analysis by 3D X-ray microtomography and mechanical behavior of biomimetic organic-inorganic composite materials.

PubMed

Alonso-Sierra, S; Velázquez-Castillo, R; Millán-Malo, B; Nava, R; Bucio, L; Manzano-Ramírez, A; Cid-Luna, H; Rivera-Muñoz, E M

2017-11-01

Hydroxyapatite-based materials have been used for dental and biomedical applications. They are commonly studied due to their favorable response presented when used for replacement of bone tissue. Those materials should be porous enough to allow cell penetration, internal tissue growth, vascular incursion and nutrient supply. Furthermore, their morphology should be designed to guide the growth of new bone tissue in anatomically applicable ways. In this work, the mechanical performance and 3D X-ray microtomography (X-ray μCT) study of a biomimetic, organic-inorganic composite material, based on hydroxyapatite, with physicochemical, structural, morphological and mechanical properties very similar to those of natural bone tissue is reported. Ceramic pieces in different shapes and several porous sizes were produced using a Modified Gel Casting Method. Pieces with a controlled and 3D hierarchical interconnected porous structure were molded by adding polymethylmethacrylate microspheres. Subsequently, they were subject to a thermal treatment to remove polymers and to promote a sinterization of the ceramic particles, obtaining a HAp scaffold with controlled porosity. Then, two different organic phases were used to generate an organic-inorganic composite material, so gelatin and collagen, which was extracted from bovine tail, were used. The biomimetic organic-inorganic composite material was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, X-ray Diffraction, Fourier Transform Infrared Spectroscopy and 3D X-ray microtomography techniques. Mechanical properties were characterized in compression tests, obtaining a dramatic and synergic increment in the mechanical properties due to the chemical and physical interactions between the two phases and to the open-cell cellular behavior of the final composite material; the maximum compressive strength obtained corresponds to about 3 times higher than that reported for natural cancellous bone. The pore size distribution obtained could be capable to allow cell penetration, internal tissue in-growth, vascular incursion and nutrient supply and this material has tremendous potential for use as a replacement of bone tissue or in the manufacture and molding of prosthesis with desired shapes. Copyright © 2017 Elsevier B.V. All rights reserved.

Demineralized dentin matrix composite collagen material for bone tissue regeneration.

PubMed

Li, Jianan; Yang, Juan; Zhong, Xiaozhong; He, Fengrong; Wu, Xiongwen; Shen, Guanxin

2013-01-01

Demineralized dentin matrix (DDM) had been successfully used in clinics as bone repair biomaterial for many years. However, particle morphology of DDM limited it further applications. In this study, DDM and collagen were prepared to DDM composite collagen material. The surface morphology of the material was studied by scanning electron microscope (SEM). MC3T3-E1 cells responses in vitro and tissue responses in vivo by implantation of DDM composite collagen material in bone defect of rabbits were also investigated. SEM analysis showed that DDM composite collagen material evenly distributed and formed a porous scaffold. Cell culture and animal models results indicated that DDM composite collagen material was biocompatible and could support cell proliferation and differentiation. Histological evaluation showed that DDM composite collagen material exhibited good biocompatibility, biodegradability and osteoconductivity with host bone in vivo. The results suggested that DDM composite collagen material might have a significant clinical advantage and potential to be applied in bone and orthopedic surgery.

Polymeric scaffolds as stem cell carriers in bone repair.

PubMed

Rossi, Filippo; Santoro, Marco; Perale, Giuseppe

2015-10-01

Although bone has a high potential to regenerate itself after damage and injury, the efficacious repair of large bone defects resulting from resection, trauma or non-union fractures still requires the implantation of bone grafts. Materials science, in conjunction with biotechnology, can satisfy these needs by developing artificial bones, synthetic substitutes and organ implants. In particular, recent advances in polymer science have provided several innovations, underlying the increasing importance of macromolecules in this field. To address the increasing need for improved bone substitutes, tissue engineering seeks to create synthetic, three-dimensional scaffolds made from polymeric materials, incorporating stem cells and growth factors, to induce new bone tissue formation. Polymeric materials have shown a great affinity for cell transplantation and differentiation and, moreover, their structure can be tuned in order to maintain an adequate mechanical resistance and contemporarily be fully bioresorbable. This review emphasizes recent progress in polymer science that allows relaible polymeric scaffolds to be synthesized for stem cell growth in bone regeneration. Copyright © 2013 John Wiley & Sons, Ltd.

Current trends and future perspectives of bone substitute materials - from space holders to innovative biomaterials.

PubMed

Kolk, Andreas; Handschel, Jörg; Drescher, Wolf; Rothamel, Daniel; Kloss, Frank; Blessmann, Marco; Heiland, Max; Wolff, Klaus-Dietrich; Smeets, Ralf

2012-12-01

An autologous bone graft is still the ideal material for the repair of craniofacial defects, but its availability is limited and harvesting can be associated with complications. Bone replacement materials as an alternative have a long history of success. With increasing technological advances the spectrum of grafting materials has broadened to allografts, xenografts, and synthetic materials, providing material specific advantages. A large number of bone-graft substitutes are available including allograft bone preparations such as demineralized bone matrix and calcium-based materials. More and more replacement materials consist of one or more components: an osteoconductive matrix, which supports the ingrowth of new bone; and osteoinductive proteins, which sustain mitogenesis of undifferentiated cells; and osteogenic cells (osteoblasts or osteoblast precursors), which are capable of forming bone in the proper environment. All substitutes can either replace autologous bone or expand an existing amount of autologous bone graft. Because an understanding of the properties of each material enables individual treatment concepts this review presents an overview of the principles of bone replacement, the types of graft materials available, and considers future perspectives. Bone substitutes are undergoing a change from a simple replacement material to an individually created composite biomaterial with osteoinductive properties to enable enhanced defect bridging. Copyright © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Molecular Abnormalities Underlying Bone Fragility in Chronic Kidney Disease

PubMed Central

Iwasaki, Yoshiko; Kazama, Junichiro James

2017-01-01

Prevention of bone fractures is one goal of therapy for patients with chronic kidney disease-mineral and bone disorder (CKD-MBD), as indicated by the Kidney Disease: Improving Global Outcomes guidelines. CKD patients, including those on hemodialysis, are at higher risk for fractures and fracture-related death compared to people with normal kidney function. However, few clinicians focus on this issue as it is very difficult to estimate bone fragility. Additionally, uremia-related bone fragility has a more complicated pathological process compared to osteoporosis. There are many uremia-associated factors that contribute to bone fragility, including severe secondary hyperparathyroidism, skeletal resistance to parathyroid hormone, and bone mineralization disorders. Uremia also aggravates bone volume loss, disarranges microarchitecture, and increases the deterioration of material properties of bone through abnormal bone cells or excess oxidative stress. In this review, we outline the prevalence of fractures, the interaction of CKD-MBD with osteoporosis in CKD patients, and discuss possible factors that exacerbate the mechanical properties of bone. PMID:28421193

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

3D Printing of Lotus Root-Like Biomimetic Materials for Cell Delivery and Tissue Regeneration.

PubMed

Feng, Chun; Zhang, Wenjie; Deng, Cuijun; Li, Guanglong; Chang, Jiang; Zhang, Zhiyuan; Jiang, Xinquan; Wu, Chengtie

2017-12-01

Biomimetic materials have drawn more and more attention in recent years. Regeneration of large bone defects is still a major clinical challenge. In addition, vascularization plays an important role in the process of large bone regeneration and microchannel structure can induce endothelial cells to form rudimentary vasculature. In recent years, 3D printing scaffolds are major materials for large bone defect repair. However, these traditional 3D scaffolds have low porosity and nonchannel structure, which impede angiogenesis and osteogenesis. In this study, inspired by the microstructure of natural plant lotus root, biomimetic materials with lotus root-like structures are successfully prepared via a modified 3D printing strategy. Compared with traditional 3D materials, these biomimetic materials can significantly improve in vitro cell attachment and proliferation as well as promote in vivo osteogenesis, indicating potential application for cell delivery and bone regeneration.

3D Printing of Lotus Root‐Like Biomimetic Materials for Cell Delivery and Tissue Regeneration

PubMed Central

Feng, Chun; Zhang, Wenjie; Deng, Cuijun; Li, Guanglong; Chang, Jiang; Zhang, Zhiyuan

2017-01-01

Abstract Biomimetic materials have drawn more and more attention in recent years. Regeneration of large bone defects is still a major clinical challenge. In addition, vascularization plays an important role in the process of large bone regeneration and microchannel structure can induce endothelial cells to form rudimentary vasculature. In recent years, 3D printing scaffolds are major materials for large bone defect repair. However, these traditional 3D scaffolds have low porosity and nonchannel structure, which impede angiogenesis and osteogenesis. In this study, inspired by the microstructure of natural plant lotus root, biomimetic materials with lotus root‐like structures are successfully prepared via a modified 3D printing strategy. Compared with traditional 3D materials, these biomimetic materials can significantly improve in vitro cell attachment and proliferation as well as promote in vivo osteogenesis, indicating potential application for cell delivery and bone regeneration. PMID:29270348

Calcium phosphate coating on titanium using laser and plasma spray

NASA Astrophysics Data System (ADS)

Roy, Mangal

Though calcium phosphate (CaP) coated implants are commercially available, its acceptance is still not wide spread due to challenges related to weaker interfacial bonding between metal and ceramic, and low crystallinity of hydroxyapatite (HA). The objectives of this research are to improve interfacial strength, crystallinity, phase purity and bioactivity of CaP coated metallic implants for orthopaedic applications. The rationale is that forming a diffuse and gradient metal-ceramic interface will improve the interfacial strength. Moreover, reducing CaP particles exposure to high temperature during coating preparation, can lead to improvement in both crystallinity and phase purity of CaP. In this study, laser engineered net shaping (LENS(TM)) was used to coat Ti metal with CaP. LENS(TM) processing enabled generation of Ti+TCP (tricalcium phosphate) composite coating with diffused interface, that also increased the coating hardness to 1049+/-112 Hv compared to a substrate hardness of 200+/-15 Hv. In vitro bone cell-material interaction studies confirmed the bioactivity of TCP coatings. Antimicrobial properties of the TCP coatings were improved by silver (Ag) electrodeposition. Along with LENS(TM), radio frequency induction plasma spray, equipped with supersonic plasma nozzle, was used to prepare HA coatings on Ti with improved crystallinity and phase purity. The coating was made of multigrain HA particles of ˜200 nm in size, which consisted of 15--20 nm HA grains. In vitro bone cell-material interaction and in vivo rat model studies confirmed the HA coatings to be bioactive. Furthermore, incorporation of Sr2+ improved bone cell of HA coatings interaction. A combination of LENS(TM) and plasma spray was used to fabricate a compositionally graded HA coatings on Ti where the microstructure varied from pure HA at the surface to pure Ti substrate with a diffused Ti+TCP composite region in between. The plasma spray system was used to synthesize spherical HA nano powder from HA sol, where the production rate was 20 g/h, which is only 16% of the total powder produced. The effects of Sr2+ and Mg2+ doping on bone cell-CaP interaction was further studied with osteoclast cells. Mg2+ doing was found to be an effective way of controlling osteoclast differentiation.

Clinical efficacy of stem cell mediated osteogenesis and bioceramics for bone tissue engineering.

PubMed

Neman, Josh; Hambrecht, Amanda; Cadry, Cherie; Goodarzi, Amir; Youssefzadeh, Jonathan; Chen, Mike Y; Jandial, Rahul

2012-01-01

Lower back pain is a common disorder that often requires bony spinal fusion for long-term relief. Current arthrodesis procedures use bone grafts from autogenous bone, allogenic backed bone or synthetic materials. Autogenous bone grafts can result in donor site morbidity and pain at the donor site, while allogenic backed bone and synthetic materials have variable effectiveness. Given these limitations, researchers have focused on new treatments that will allow for safe and successful bone repair and regeneration. Mesenchymal stem cells (MSCs) have received attention for their ability to differentiate into osteoblasts, cells that synthesize the extracellular matrix and regulate matrix mineralization. Successful bone regeneration requires three elements: MSCs that serve as osteoblastic progenitors, osteoinductive growth factors and their pathways that promote development and differentiation of the cells as well as an osteoconductive scaffold that allows for the formation of a vascular network. Future treatments should strive to combine mesenchymal stem cells, cell-seeded scaffolds and gene therapy to optimize the efficiency and safety of tissue repair and bone regeneration.

Age-related mechanical strength evolution of trabecular bone under fatigue damage for both genders: Fracture risk evaluation.

PubMed

Ben Kahla, Rabeb; Barkaoui, Abdelwahed; Merzouki, Tarek

2018-08-01

Bone tissue is a living composite material, providing mechanical and homeostatic functions, and able to constantly adapt its microstructure to changes in long term loading. This adaptation is conducted by a physiological process, known as "bone remodeling". This latter is manifested by interactions between osteoclasts and osteoblasts, and can be influenced by many local factors, via effects on bone cell differentiation and proliferation. In the current work, age and gender effects on damage rate evolution, throughout life, have been investigated using a mechanobiological finite element modeling. To achieve the aim, a mathematical model has been developed, coupling both cell activities and mechanical behavior of trabecular bone, under cyclic loadings. A series of computational simulations (ABAQUS/UMAT) has been performed on a 3D human proximal femur, allowing to investigate the effects of mechanical and biological parameters on mechanical strength of trabecular bone, in order to evaluate the fracture risk resulting from fatigue damage. The obtained results revealed that mechanical stimulus amplitude affects bone resorption and formation rates, and indicated that age and gender are major factors in bone response to the applied loadings. Copyright © 2018 Elsevier Ltd. All rights reserved.

Natural-based nanocomposites for bone tissue engineering and regenerative medicine: a review.

PubMed

Pina, Sandra; Oliveira, Joaquim M; Reis, Rui L

2015-02-18

Tissue engineering and regenerative medicine has been providing exciting technologies for the development of functional substitutes aimed to repair and regenerate damaged tissues and organs. Inspired by the hierarchical nature of bone, nanostructured biomaterials are gaining a singular attention for tissue engineering, owing their ability to promote cell adhesion and proliferation, and hence new bone growth, compared with conventional microsized materials. Of particular interest are nanocomposites involving biopolymeric matrices and bioactive nanosized fillers. Biodegradability, high mechanical strength, and osteointegration and formation of ligamentous tissue are properties required for such materials. Biopolymers are advantageous due to their similarities with extracellular matrices, specific degradation rates, and good biological performance. By its turn, calcium phosphates possess favorable osteoconductivity, resorbability, and biocompatibility. Herein, an overview on the available natural polymer/calcium phosphate nanocomposite materials, their design, and properties is presented. Scaffolds, hydrogels, and fibers as biomimetic strategies for tissue engineering, and processing methodologies are described. The specific biological properties of the nanocomposites, as well as their interaction with cells, including the use of bioactive molecules, are highlighted. Nanocomposites in vivo studies using animal models are also reviewed and discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon nanotube interaction with extracellular matrix proteins producing scaffolds for tissue engineering

PubMed Central

Tonelli, Fernanda MP; Santos, Anderson K; Gomes, Katia N; Lorençon, Eudes; Guatimosim, Silvia; Ladeira, Luiz O; Resende, Rodrigo R

2012-01-01

In recent years, significant progress has been made in organ transplantation, surgical reconstruction, and the use of artificial prostheses to treat the loss or failure of an organ or bone tissue. In recent years, considerable attention has been given to carbon nanotubes and collagen composite materials and their applications in the field of tissue engineering due to their minimal foreign-body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth, proliferation, and differentiation. Recently, grafted collagen and some other natural and synthetic polymers with carbon nanotubes have been incorporated to increase the mechanical strength of these composites. Carbon nanotube composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. PMID:22923989

Role of chemical and mechanical stimuli in mediating bone fracture healing.

PubMed

Zhang, Lihai; Richardson, Martin; Mendis, Priyan

2012-08-01

Bone is a remarkable living tissue that provides a framework for animal body support and motion. However, under excessive loads and deformations, bone is prone is to damage through fracture. Furthermore, once the bone is weakened by osteoporosis, bone fracture can occur even after only minimal trauma. Various techniques have been developed to treat bone fractures. Successful treatment outcomes depend on a fundamental understanding of the biochemical and biomechanical environments of the fracture site. Various cell types (e.g. mesenchymal stem cells, chondrocytes, osteoblasts and osteoclasts) within the fracture site tightly control the healing process by responding to the chemical and mechanical microenvironment. However, these mechanochemical regulatory mechanisms remain poorly understood at the system level owing to the large range of variables, such as age, sex and disease-associated material properties of the tissue. Computational modelling can play an important role in unravelling this complexity by combining mechanochemical interactions, revealing the dominant controlling processes and optimizing system behaviour, thereby enabling the development and evaluation of treatment strategies for individual patients. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Biomimetic mineralization of recombinant collagen type I derived protein to obtain hybrid matrices for bone regeneration.

PubMed

Ramírez-Rodríguez, Gloria Belén; Delgado-López, José Manuel; Iafisco, Michele; Montesi, Monica; Sandri, Monica; Sprio, Simone; Tampieri, Anna

2016-11-01

Understanding the mineralization mechanism of synthetic protein has recently aroused great interest especially in the development of advanced materials for bone regeneration. Herein, we propose the synthesis of composite materials through the mineralization of a recombinant collagen type I derived protein (RCP) enriched with RGD sequences in the presence of magnesium ions (Mg) to closer mimic bone composition. The role of both RCP and Mg ions in controlling the precipitation of the mineral phase is in depth evaluated. TEM and X-ray powder diffraction reveal the crystallization of nanocrystalline apatite (Ap) in all the evaluated conditions. However, Raman spectra point out also the precipitation of amorphous calcium phosphate (ACP). This amorphous phase is more evident when RCP and Mg are at work, indicating the synergistic role of both in stabilizing the amorphous precursor. In addition, hybrid matrices are prepared to tentatively address their effectiveness as scaffolds for bone tissue engineering. SEM and AFM imaging show an homogeneous mineral distribution on the RCP matrix mineralized in presence of Mg, which provides a surface roughness similar to that found in bone. Preliminary in vitro tests with pre-osteoblast cell line show good cell-material interaction on the matrices prepared in the presence of Mg. To the best of our knowledge this work represents the first attempt to mineralize recombinant collagen type I derived protein proving the simultaneous effect of the organic phase (RCP) and Mg on ACP stabilization. This study opens the possibility to engineer, through biomineralization process, advanced hybrid matrices for bone regeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate bone substitute granules in caprine muscle tissue does not induce new bone formation.

PubMed

Ghanaati, Shahram; Udeabor, Samuel E; Barbeck, Mike; Willershausen, Ines; Kuenzel, Oliver; Sader, Robert A; Kirkpatrick, C James

2013-01-04

Osteoinductive bone substitutes are defined by their ability to induce new bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different bone substitute materials in caprine muscle tissue. One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO2)-based nanocrystalline bone substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized bone matrix. Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped bone substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting.

Mature adipocytes in bone marrow protect myeloma cells against chemotherapy through autophagy activation

USDA-ARS?s Scientific Manuscript database

A major problem in patients with multiple myeloma is chemotherapy resistance, which develops in myeloma cells upon interaction with bone marrow stromal cells. However, few studies have determined the role of bone marrow adipocytes, a major component of stromal cells in the bone marrow, in myeloma ch...

Effect of small peptide (P-15) on HJMSCs adhesion to hydroxyap-atite

NASA Astrophysics Data System (ADS)

Cheng, Wei; Tong, Xin; Hu, QinGang; Mou, YongBin; Qin, HaiYan

2016-02-01

P-15, a synthetic peptide of 15-amino acids, has been tested in clinical trials to enhance cell adhesion and promote osseointe- gration. This feature of P-15 has also inspired the development of designing new bone substitute materials. Despite the increasing applications of P-15 in bone graft alternatives, few studies focus on the mechanism of cell adhesion promoted by P-15 and the mechanical property changes of the cells interacting with P-15. In this article, we used atomic force microscope (AFM) based single cell indentation force spectroscopy to study the impact of P-15 on the stiffness and the adhesion ability of human jaw bone mesenchymal stem cells (HJMSCs) to hydroxyapatite (HA). We found that the stiffness of HJMSCs increases as the concentration of P-15 grows in short culture intervals and that the adhesion forces between HJMSCs and HA particles in both the presence and absence of P-15 are all around 30pN. Moreover, by calculating the binding energy of HJMSCs to HA particles mixed with and without P-15, we proved that P-15 could increase the adhesion energy by nearly four times. Scanning electron microscope (SEM) was also exploited to study the morphology of HJMSCs cultured in the presence and absence of P-15 on HA disc surface for a short term. Apparent morphological differences were observed between the cells cultured with and without P-15. These results explain the probable underlying adhesion mechanism of HJMSC promoted by P-15 and can serve as the bases for the design of bone graft substitute materials.

Double-layered cell transfer technology for bone regeneration

PubMed Central

Akazawa, Keiko; Iwasaki, Kengo; Nagata, Mizuki; Yokoyama, Naoki; Ayame, Hirohito; Yamaki, Kazumasa; Tanaka, Yuichi; Honda, Izumi; Morioka, Chikako; Kimura, Tsuyoshi; Komaki, Motohiro; Kishida, Akio; Izumi, Yuichi; Morita, Ikuo

2016-01-01

For cell-based medicine, to mimic in vivo cellular localization, various tissue engineering approaches have been studied to obtain a desirable arrangement of cells on scaffold materials. We have developed a novel method of cell manipulation called “cell transfer technology”, enabling the transfer of cultured cells onto scaffold materials, and controlling cell topology. Here we show that using this technique, two different cell types can be transferred onto a scaffold surface as stable double layers or in patterned arrangements. Various combinations of adherent cells were transferred to a scaffold, amniotic membrane, in overlapping bilayers (double-layered cell transfer), and transferred cells showed stability upon deformations of the material including folding and trimming. Transplantation of mesenchymal stem cells from periodontal ligaments (PDLSC) and osteoblasts, using double-layered cell transfer significantly enhanced bone formation, when compared to single cell type transplantation. Our findings suggest that this double-layer cell transfer is useful to produce a cell transplantation material that can bear two cell layers. Moreover, the transplantation of an amniotic membrane with PDLSCs/osteoblasts by cell transfer technology has therapeutic potential for bone defects. We conclude that cell transfer technology provides a novel and unique cell transplantation method for bone regeneration. PMID:27624174

Improved bone marrow stromal cell adhesion on micropatterned titanium surfaces.

PubMed

Iskandar, Maria E; Cipriano, Aaron F; Lock, Jaclyn; Gott, Shannon C; Rao, Masaru P; Liu, Huinan

2012-01-01

Implant longevity is desired for all bone replacements and fixatives. Titanium (Ti) implants fail due to lack of juxtaposed bone formation, resulting in implant loosening. Implant surface modifications have shown to affect the interactions between the implant and bone. In clinical applications, it is crucial to improve osseointegration and implant fixation at the implant and bone interface. Moreover, bone marrow derived cells play a significant role for implant and tissue integration. Therefore, the objective of this study is to investigate how surface micropatterning on Ti influences its interactions with bone marrow derived cells containing mesenchymal and hematopoietic stem cells. Bone marrow derived mesenchymal stem cells (BMSC) have the capability of differentiating into osteoblasts that contribute to bone growth, and therefore implant/bone integration. Hematopoietic stem cell derivatives are precursor cells that contribute to inflammatory response. By using all three cells naturally contained within bone marrow, we mimic the physiological environment to which an implant is exposed. Primary rat bone marrow derived cells were seeded onto Ti with surfaces composed of arrays of grooves of equal width and spacing ranging from 0.5 to 50 µm, fabricated using a novel plasma-based dry etching technique. Results demonstrated enhanced total cell adhesion on smaller micrometer-scale Ti patterns compared with larger micrometer-scale Ti patterns, after 24-hr culture. Further studies are needed to determine bone marrow derived cell proliferation and osteogenic differentiation potential on micropatterned Ti, and eventually nanopatterned Ti.

The material and biological characteristics of osteoinductive calcium phosphate ceramics

PubMed Central

Tang, Zhurong; Li, Xiangfeng; Tan, Yanfei

2018-01-01

Abstract The discovery of osteoinductivity of calcium phosphate (Ca-P) ceramics has set an enduring paradigm of conferring biological regenerative activity to materials with carefully designed structural characteristics. The unique phase composition and porous structural features of osteoinductive Ca-P ceramics allow it to interact with signaling molecules and extracellular matrices in the host system, creating a local environment conducive to new bone formation. Mounting evidence now indicate that the osteoinductive activity of Ca-P ceramics is linked to their physicochemical and three-dimensional structural properties. Inspired by this conceptual breakthrough, many laboratories have shown that other materials can be also enticed to join the rank of tissue-inducing biomaterials, and besides the bones, other tissues such as cartilage, nerves and blood vessels were also regenerated with the assistance of biomaterials. Here, we give a brief historical recount about the discovery of the osteoinductivity of Ca-P ceramics, summarize the underlying material factors and biological characteristics, and discuss the mechanism of osteoinduction concerning protein adsorption, and the interaction with different types of cells, and the involvement of the vascular and immune systems. PMID:29423267

Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

PubMed Central

Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

2017-01-01

The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics. PMID:28240268

Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration.

PubMed

Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

2017-02-27

The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO 3 ) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d 33 of HA/BaTiO 3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO 3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO 3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO 3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO 3 piezoelectric ceramics.

Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

NASA Astrophysics Data System (ADS)

Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

2017-02-01

The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics.

New mechanisms and targets in the treatment of bone fragility.

PubMed

Martin, T John; Seeman, Ego

2007-01-01

Bone modelling and remodelling are cell-mediated processes responsible for the construction and reconstruction of the skeleton throughout life. These processes are chiefly mediated by locally generated cytokines and growth factors that regulate the differentiation, activation, work and life span of osteoblasts and osteoclasts, the cells that co-ordinate the volumes of bone resorbed and formed. In this way, the material composition and structural design of bone is regulated in accordance with its loading requirements. Abnormalities in this regulatory system compromise the material and structural determinants of bone strength producing bone fragility. Understanding the intercellular control processes that regulate bone modelling and remodelling is essential in planning therapeutic approaches to prevention and treatment of bone fragility. A great deal has been learnt in the last decade. Clinical trials carried out exclusively with drugs that inhibit bone resorption have identified the importance of reducing the rate of bone remodelling and so the progression of bone fragility to achieved fracture reductions of approx. 50%. These trials have also identified limitations that should be placed upon interpretation of bone mineral density changes in relation to treatment. New resorption inhibitors are being developed, based on mechanisms of action that are different from existing drugs. Some of these might offer resorption inhibition without reducing bone formation. More recent research has provided the first effective anabolic therapy for bone reconstruction. Daily injections of PTH (parathyroid hormone)-(1-34) have been shown in preclinical studies and in a large clinical trial to increase bone tissue mass and reduce the risk of fractures. The action of PTH differs from that of the resorption inhibitors, but whether it is more effective in fracture reduction is not known. Understanding the cellular and molecular mechanisms of PTH action, particularly its interactions with other pathways in determining bone formation, is likely to lead to new therapeutic developments. The recent discovery through mouse genetics that PTHrP (PTH-related protein) is a crucial bone-derived paracrine regulator of remodelling offers new and interesting therapeutic targets.

Recent advances in synthesis, characterization of hydroxyapatite/polyurethane composites and study of their biocompatible properties.

PubMed

Popescu, L M; Piticescu, R M; Antonelli, A; Rusti, C F; Carboni, E; Sfara, C; Magnani, M; Badilita, V; Vasile, E; Trusca, R; Buruiana, T

2013-11-01

The development of engineered biomaterials that mimic bone tissues is a promising research area that benefits from a growing interest. Polymers and polymer-ceramic composites are the principle materials investigated for the development of synthetic bone scaffolds thanks to their proven biocompatibility and biostability. Several polymers have been combined with calcium phosphates (mainly hydroxyapatite) to prepare nanocomposites with improved biocompatible and mechanical properties. Here, we report the hydrothermal synthesis in high pressure conditions of nanostructured composites based on hydroxyapatite and polyurethane functionalized with carboxyl and thiol groups. Cell-material interactions were investigated for potential applications of these new types of composites as coating for orthopedic implants. Physical-chemical and morphological characteristics of hydroxyapatite/polyurethane composites were evaluated for different compositions, showing their dependence on synthesis parameters (pressure, temperature). In vitro experiments, performed to verify if these composites are biocompatible cell culture substrates, showed that they are not toxic and do not affect cell viability.

Chitosan Composites for Bone Tissue Engineering—An Overview

PubMed Central

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca10(PO4)6(OH)2] is one of the most stable forms of calcium phosphate and it occurs in bones as major component (60 to 65%), along with other materials including collagen, chondroitin sulfate, keratin sulfate and lipids. In recent years, significant progress has been made in organ transplantation, surgical reconstruction and the use of artificial protheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed. PMID:20948907

Disruption of Annexin II /p11 Interaction Suppresses Leukemia Cell Binding, Homing and Engraftment, and Sensitizes the Leukemia Cells to Chemotherapy.

PubMed

Gopalakrishnapillai, Anilkumar; Kolb, E Anders; Dhanan, Priyanka; Mason, Robert W; Napper, Andrew; Barwe, Sonali P

2015-01-01

The bone marrow microenvironment plays an important role in acute lymphoblastic leukemia (ALL) cell proliferation, maintenance, and resistance to chemotherapy. Annexin II (ANX2) is abundantly expressed on bone marrow cells and complexes with p11 to form ANX2/p11-hetero-tetramer (ANX2T). We present evidence that p11 is upregulated in refractory ALL cell lines and patient samples. A small molecule inhibitor that disrupts ANX2/p11 interaction (ANX2T inhibitor), an anti-ANX2 antibody, and knockdown of p11, abrogated ALL cell adhesion to osteoblasts, indicating that ANX2/p11 interaction facilitates binding and retention of ALL cells in the bone marrow. Furthermore, ANX2T inhibitor increased the sensitivity of primary ALL cells co-cultured with osteoblasts to dexamethasone and vincristine induced cell death. Finally, in an orthotopic leukemia xenograft mouse model, the number of ALL cells homing to the bone marrow was reduced by 40-50% in mice injected with anti-ANX2 antibody, anti-p11 antibody or ANX2T inhibitor compared to respective controls. In a long-term engraftment assay, the percentage of ALL cells in mouse blood, bone marrow and spleen was reduced in mice treated with agents that disrupt ANX2/p11 interaction. These data show that disruption of ANX2/p11 interaction results in reduced ALL cell adhesion to osteoblasts, increased ALL cell sensitization to chemotherapy, and suppression of ALL cell homing and engraftment.

Hydroxyapatite nanorod and microsphere functionalized with bioactive lactoferrin as a new biomaterial for enhancement bone regeneration.

PubMed

Shi, Pujie; Wang, Qun; Yu, Cuiping; Fan, Fengjiao; Liu, Meng; Tu, Maolin; Lu, Weihong; Du, Ming

2017-07-01

Lactoferrin (LF) has been recently recognized as a promising new novel bone growth factor for the beneficial effects on bone cells and promotion of bone growth. Currently, it has been attracted wide attention in bone regeneration as functional food additives or a potential bioactive protein in bone tissue engineering. The present study investigated the possibility that hydroxyapatite (HAP) particles, a widely used bone substitute material for high biocompatibility and osteoconductivity, functionalized with lactoferrin as a composite material are applied to bone tissue engineering. Two kinds of hydroxyapatite samples with different sizes, including nanorods and microspheres particles, were functionalized with lactoferrin molecules, respectively. A detailed characterization of as-prepared HAP-LF complex is presented, combining thermal gravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). Zeta potential and the analysis of electrostatic surface potential of lactoferrin were carried to reveal the mechanism of adsorption. The effects of HAP-LF complex on MC3T3-E1 osteoblast proliferation and morphology were systematically evaluated at different culture time. Interestingly, results showed that cell viability of HAP-LF group was significantly higher than HAP group indicating that the HAP-LF can improve the biocompatibility of HAP, which mainly originated from a combination of HAP-LF interaction. These results indicated that hydroxyapatite particles can work as a controlled releasing carrier of lactoferrin successfully, and lactoferrin showed better potentiality on using in the field of bone regeneration by coupling with hydroxyapatite. This study would provide a new biomaterial and might offer a new insight for enhancement of bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Reduced Graphene Oxide-Coated Biphasic Calcium Phosphate Bone Graft Material on Osteogenesis

PubMed Central

Kim, Jeong-Woo; Lee, Jin-Ju; Bae, Eun-Bin; Jeon, Young-Chan; Jeong, Chang-Mo; Yun, Mi-Jung; Lee, So-Hyoun; Huh, Jung-Bo

2017-01-01

This study was conducted to evaluate the effect of biphasic calcium phosphate (BCP) coated with reduced graphene oxide (rGO) as bone graft materials on bone regeneration. The rGO-coated BCP bone graft material was fabricatied by mixing rGO and BCP at various concentrations. The surface charge of rGO-coated BCP was measured to be −14.43 mV, which formed a static electrostatic interaction. Cell viabilities were significantly diminished at higher concentrations of ≥100 μg/mL. The calvarial defects of 48 rats were implanted rGO-coated BCPs at a weight ratio of 2:1000 (rGO2), 4:1000 (rGO4), and 10:1000 (rGO10), repectively. BCP was used as a control group. The micro-CT and histological analysis were performed to evaluate new bone formation at 2 and 8 weeks after surgery. The results showed that the new bone volume (mm3) was significantly higher in the experimental groups than in the control group. Histological analysis showed that new bone areas (%) were significantly higher in the rGO2 and rGO10 than in the control, and significantly higher in rGO4 than in the rGO2 and rGO10. Conclusively, the rGO-coated BCP was found to be effective on osteogenesis and the concentration of the composite was an important factor. PMID:28786931

The Effect of Reduced Graphene Oxide-Coated Biphasic Calcium Phosphate Bone Graft Material on Osteogenesis.

PubMed

Kim, Jeong-Woo; Shin, Yong Cheol; Lee, Jin-Ju; Bae, Eun-Bin; Jeon, Young-Chan; Jeong, Chang-Mo; Yun, Mi-Jung; Lee, So-Hyoun; Han, Dong-Wook; Huh, Jung-Bo

2017-08-08

This study was conducted to evaluate the effect of biphasic calcium phosphate (BCP) coated with reduced graphene oxide (rGO) as bone graft materials on bone regeneration. The rGO-coated BCP bone graft material was fabricatied by mixing rGO and BCP at various concentrations. The surface charge of rGO-coated BCP was measured to be -14.43 mV, which formed a static electrostatic interaction. Cell viabilities were significantly diminished at higher concentrations of ≥100 μg/mL. The calvarial defects of 48 rats were implanted rGO-coated BCPs at a weight ratio of 2:1000 (rGO2), 4:1000 (rGO4), and 10:1000 (rGO10), repectively. BCP was used as a control group. The micro-CT and histological analysis were performed to evaluate new bone formation at 2 and 8 weeks after surgery. The results showed that the new bone volume (mm³) was significantly higher in the experimental groups than in the control group. Histological analysis showed that new bone areas (%) were significantly higher in the rGO2 and rGO10 than in the control, and significantly higher in rGO4 than in the rGO2 and rGO10. Conclusively, the rGO-coated BCP was found to be effective on osteogenesis and the concentration of the composite was an important factor.

Development of a new carbon nanotube–alginate–hydroxyapatite tricomponent composite scaffold for application in bone tissue engineering

PubMed Central

Rajesh, Rajendiran; Dominic Ravichandran, Y

2015-01-01

In recent times, tricomponent scaffolds prepared from naturally occurring polysaccharides, hydroxyapatite, and reinforcing materials have been gaining increased attention in the field of bone tissue engineering. In the current work, a tricomponent scaffold with an oxidized multiwalled carbon nanotube (fMWCNT)–alginate–hydroxyapatite with the required porosity was prepared for the first time by a freeze-drying method and characterized using analytical techniques. The hydroxyapatite for the scaffold was isolated from chicken bones by thermal calcination at 800°C. The Fourier transform infrared spectra and X-ray diffraction data confirmed ionic interactions and formation of the fMWCNT–alginate–hydroxyapatite scaffold. Interconnected porosity with a pore size of 130–170 µm was evident from field emission scanning electron microscopy. The total porosity calculated using the liquid displacement method was found to be 93.85%. In vitro biocompatibility and cell proliferation on the scaffold was checked using an MG-63 cell line by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell attachment by Hoechst stain assay. In vitro studies showed better cell proliferation, cell differentiation, and cell attachment on the prepared scaffold. These results indicate that this scaffold could be a promising candidate for bone tissue engineering. PMID:26491303

A reciprocal regulatory interaction between megakaryocytes, bone cells, and hematopoietic stem cells.

PubMed

Kacena, Melissa A; Gundberg, Caren M; Horowitz, Mark C

2006-11-01

A growing body of evidence suggests that megakaryocytes (MK) or their growth factors play a role in skeletal homeostasis. MK have been shown to express and/or secrete several bone-related proteins including osteocalcin, osteonectin, bone sialoprotein, osteopontin, bone morphogenetic proteins, and osteoprotegerin. In addition, at least 3 mouse models have been described in which MK number was significantly elevated with an accompanying marked increase in bone mineral density. Mice overexpressing thrombopoietin, the major MK growth factor, have an osteosclerotic bone phenotype. Mice deficient in transcription factors GATA-1 and NF-E2, which are required for the differentiation of MK, exhibited a strikingly increased bone mass. Importantly, recent studies have demonstrated that MK can stimulate osteoblast (OB) proliferation and differentiation in vitro and that they can also inhibit osteoclast (OC) formation in vitro. These findings suggest that MK play a dual role in skeletal homeostasis by stimulating formation while simultaneously inhibiting resorption. Conversely, cells of the osteoblast lineage support hematopoiesis, including megakaryopoiesis. Postnatal hematopoiesis occurs almost solely in the bone marrow (BM), close to or on endosteal surfaces. This finding, in conjunction with the observed contact of OB with hematopoietic cells, has lead investigators to explore the molecular and cellular interactions between hematopoietic cells and cells of the OB lineage. Importantly, it has been shown that many of the cytokines that are critical for normal hematopoiesis and megakaryopoiesis are produced by OB. Indeed, culturing osteoblasts with CD34+ BM cells significantly enhances hematopoietic cell number by both enhancing the proliferation of long-term culture initiating cells and the proliferation and differentiation of MK. These data are consistent with cells in the OB lineage playing a critical role in the hematopoietic niche. Overall, these observations demonstrate the importance of MK-bone cell interactions in both skeletal homeostasis and hematopoiesis.

Synthetic octacalcium phosphate: a possible carrier for mesenchymal stem cells in bone regeneration.

PubMed

Suzuki, Osamu; Anada, Takahisa

2013-01-01

The present paper reviews biomaterial studies of synthetic octacalcium phosphate (OCP) as a scaffold of osteoblastic cells. OCP crystals have been suggested to be one of precursor phases in hydroxyapatite (HA) crystal formation in bone and tooth. The recent intensive biomaterials and tissue engineering studies using synthetic OCP disclosed the potential function of OCP as a bioactive material as well as synthetic HA materials due to its highly osteoconductive and biodegradable properties. In vitro studies showed that OCP crystals exhibit a positive effect on osteoblastic cell differentiation. In vivo studies confirmed that the materials of OCP in a granule forms and OCP-based composite materials with natural polymers, such as gelatin and collagen, enhance bone regeneration if implanted in various model bone defects with critical-sized diameters, defined as a defect which does not heal spontaneously throughout the lifetime of the animals. One of particular characteristics of OCP, found as a mechanism to enhance bone regeneration in vivo, is a process of progressive conversion from OCP to HA at physiological conditions. The OCP-HA conversion is accompanied by progressive physicochemical changes of the material properties, which affects the tissue reaction around the crystals where osteoblastic cells are encountered. Mesenchymal stem cells (MSCs) seeded in an OCP-based material enhanced bone regeneration in the rat critical-sized calvaria defect more than that by the material alone. The overall results reveal that OCP crystals have an effect on osteoblastic cell differentiation including the differentiation of MSCs in vivo. The evidence collected experimentally in the laboratory was presented.

Hard tissue regeneration using bone substitutes: an update on innovations in materials

PubMed Central

Sarkar, Swapan Kumar

2015-01-01

Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues. PMID:25995658

Hard tissue regeneration using bone substitutes: an update on innovations in materials.

PubMed

Sarkar, Swapan Kumar; Lee, Byong Taek

2015-05-01

Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues.

Role of IGF1 and EFN-EPH signaling in skeletal metabolism.

PubMed

Lindsey, Richard C; Rundle, Charles H; Mohan, Subburaman

2018-07-01

Insulin-like growth factor 1(IGF1) and ephrin ligand (EFN)-receptor (EPH) signaling are both crucial for bone cell function and skeletal development and maintenance. IGF1 signaling is the major mediator of growth hormone-induced bone growth, but a host of different signals and factors regulate IGF1 signaling at the systemic and local levels. Disruption of the Igf1 gene results in reduced peak bone mass in both experimental animal models and humans. Additionally, EFN-EPH signaling is a complex system which, particularly through cell-cell interactions, contributes to the development and differentiation of many bone cell types. Recent evidence has demonstrated several ways in which the IGF1 and EFN-EPH signaling pathways interact with and depend upon each other to regulate bone cell function. While much remains to be elucidated, the interaction between these two signaling pathways opens a vast array of new opportunities for investigation into the mechanisms of and potential therapies for skeletal conditions such as osteoporosis and fracture repair. © 2018 Society for Endocrinology.

The Effect of 3D Hydrogel Scaffold Modulus on Osteoblast Differentiation and Mineralization Revealed by Combinatorial Screening

PubMed Central

Chatterjee, Kaushik; Lin-Gibson, Sheng; Wallace, William E.; Parekh, Sapun H.; Lee, Young J.; Cicerone, Marcus T.; Young, Marian F.; Simon, Carl G.

2011-01-01

Cells are known to sense and respond to the physical properties of their environment and those of tissue scaffolds. Optimizing these cell-material interactions is critical in tissue engineering. In this work, a simple and inexpensive combinatorial platform was developed to rapidly screen three-dimensional (3D) tissue scaffolds and was applied to screen the effect of scaffold properties for tissue engineering of bone. Differentiation of osteoblasts was examined in poly(ethylene glycol) hydrogel gradients spanning a 30-fold range in compressive modulus (≈ 10 kPa to ≈ 300 kPa). Results demonstrate that material properties (gel stiffness) of scaffolds can be leveraged to induce cell differentiation in 3D culture as an alternative to biochemical cues such as soluble supplements, immobilized biomolecules and vectors, which are often expensive, labile and potentially carcinogenic. Gel moduli of ≈ 225 kPa and higher enhanced osteogenesis. Furthermore, it is proposed that material-induced cell differentiation can be modulated to engineer seamless tissue interfaces between mineralized bone tissue and softer tissues such as ligaments and tendons. This work presents a combinatorial method to screen biological response to 3D hydrogel scaffolds that more closely mimics the 3D environment experienced by cells in vivo. PMID:20378163

The materials used in bone tissue engineering

NASA Astrophysics Data System (ADS)

Tereshchenko, V. P.; Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

2015-11-01

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

Investigation of early cell–surface interactions of human mesenchymal stem cells on nanopatterned β-type titanium–niobium alloy surfaces

PubMed Central

Medda, Rebecca; Helth, Arne; Herre, Patrick; Pohl, Darius; Rellinghaus, Bernd; Perschmann, Nadine; Neubauer, Stefanie; Kessler, Horst; Oswald, Steffen; Eckert, Jürgen; Spatz, Joachim P.; Gebert, Annett; Cavalcanti-Adam, Elisabetta A.

2014-01-01

Multi-potent adult mesenchymal stem cells (MSCs) derived from bone marrow have therapeutic potential for bone diseases and regenerative medicine. However, an intrinsic heterogeneity in their phenotype, which in turn results in various differentiation potentials, makes it difficult to predict the response of these cells. The aim of this study is to investigate initial cell–surface interactions of human MSCs on modified titanium alloys. Gold nanoparticles deposited on β-type Ti–40Nb alloys by block copolymer micelle nanolithography served as nanotopographical cues as well as specific binding sites for the immobilization of thiolated peptides present in several extracellular matrix proteins. MSC heterogeneity persists on polished and nanopatterned Ti–40Nb samples. However, cell heterogeneity and donor variability decreased upon functionalization of the gold nanoparticles with cyclic RGD peptides. In particular, the number of large cells significantly decreased after 24 h owing to the arrangement of cell anchorage sites, rather than peptide specificity. However, the size and number of integrin-mediated adhesion clusters increased in the presence of the integrin-binding peptide (cRGDfK) compared with the control peptide (cRADfK). These results suggest that the use of integrin ligands in defined patterns could improve MSC-material interactions, not only by regulating cell adhesion locally, but also by reducing population heterogeneity. PMID:24501674

Extracorporeal human bone-like tissue generation

PubMed Central

Rosenberg, N.; Rosenberg, O.

2012-01-01

Objectives The need for bone tissue supplementation exists in a wide range of clinical conditions involving surgical reconstruction in limbs, the spine and skull. The bone supplementation materials currently used include autografts, allografts and inorganic matrix components; but these pose potentially serious side-effects. In particular the availability of the autografts is usually limited and their harvesting causes surgical morbidity. Therefore for the purpose of supplementation of autologous bone graft, we have developed a method for autologous extracorporeal bone generation. Methods Human osteoblast-like cells were seeded on porous granules of tricalcium phosphate and incubated in osteogenic media while exposed to mechanical stimulation by vibration in the infrasonic range of frequencies. The generated tissue was examined microscopically following haematoxylin eosin, trichrome and immunohistochemical staining. Results Following 14 days of incubation the generated tissue showed histological characteristics of bone-like material due to the characteristic eosinophilic staining, a positive staining for collagen trichrome and a positive specific staining for osteocalcin and collagen 1. Macroscopically, this tissue appeared in aggregates of between 0.5 cm and 2 cm. Conclusions We present evidence that the interaction of the cellular, inorganic and mechanical components in vitro can rapidly generate three-dimensional bone-like tissue that might be used as an autologous bone graft. PMID:23610651

Gelatine modified monetite as a bone substitute material: An in vitro assessment of bone biocompatibility.

PubMed

Kruppke, Benjamin; Farack, Jana; Wagner, Alena-Svenja; Beckmann, Sarah; Heinemann, Christiane; Glenske, Kristina; Rößler, Sina; Wiesmann, Hans-Peter; Wenisch, Sabine; Hanke, Thomas

2016-03-01

Calcium phosphate phases are increasingly used for bone tissue substitution, and the load bearing properties of these inherently brittle biomaterials are increased by inclusion of organic components. Monetite prepared using mineralization of gelatine pre-structured through phosphate leads to a significantly increased biaxial strength and indirect tensile strength compared to gelatine-free monetite. Besides the mechanical properties, degradation in physiological solutions and osteoblast and osteoclast cell response were investigated. Human bone marrow stromal cells (hBMSCs) showed considerably higher proliferation rates on the gelatine modified monetite than on polystyrene reference material in calcium-free as well as standard cell culture medium (α-MEM). Osteogenic differentiation on the material was comparable to polystyrene in both medium types. Osteoclast-like cells derived from monocytes were able to actively resorb the biomaterial. Osteoblastic differentiation and perhaps even more important the cellular resorption of the biomaterial indicate that it can be actively involved in the bone remodeling process. Thus the behavior of osteoblasts and osteoclasts as well as the adequate degradation and mechanical properties are strong indicators for bone biocompatibility, although in vivo studies are still required to prove this. New and unique? A low temperature precipitationprocessforcalcium anhydrous hydrogen phosphateallows for the first time to produce monolithic compact composites of monetite and gelatine. The composite is degradable and resorbable. To prove that, the question arises: what is bone biocompatibility? The reaction of both mayor cell types of bone represents this biocompatibility. Therefore, human bone marrow stromal cells were seeded revealing the materials pro-osteogenic properties. Monocyte cultivation, becoming recently focus of interest, revealed the capability of the biomaterial to be actively resorbed by derived osteoclast-like cells. Not new but necessary ismechanical characterization, which is often only investigated as uniaxial property. Here, a biaxial method is applied, to characterize the materials properties closer to its application loads. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biomimetic Materials and Fabrication Approaches for Bone Tissue Engineering.

PubMed

Kim, Hwan D; Amirthalingam, Sivashanmugam; Kim, Seunghyun L; Lee, Seunghun S; Rangasamy, Jayakumar; Hwang, Nathaniel S

2017-12-01

Various strategies have been explored to overcome critically sized bone defects via bone tissue engineering approaches that incorporate biomimetic scaffolds. Biomimetic scaffolds may provide a novel platform for phenotypically stable tissue formation and stem cell differentiation. In recent years, osteoinductive and inorganic biomimetic scaffold materials have been optimized to offer an osteo-friendly microenvironment for the osteogenic commitment of stem cells. Furthermore, scaffold structures with a microarchitecture design similar to native bone tissue are necessary for successful bone tissue regeneration. For this reason, various methods for fabricating 3D porous structures have been developed. Innovative techniques, such as 3D printing methods, are currently being utilized for optimal host stem cell infiltration, vascularization, nutrient transfer, and stem cell differentiation. In this progress report, biomimetic materials and fabrication approaches that are currently being utilized for biomimetic scaffold design are reviewed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of a biomimetic ZeinPDA nanofibrous scaffold impregnated with BMP-2 peptide conjugated TiO2 nanoparticle for bone tissue engineering.

PubMed

Babitha, S; Annamalai, Meenakshi; Dykas, Michal Marcin; Saha, Surajit; Poddar, Kingshuk; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Venkatesan, Thirumalai; Korrapati, Purna Sai

2018-04-01

A biomimetic Zein polydopamine based nanofiber scaffold was fabricated to deliver bone morphogenic protein-2 (BMP-2) peptide conjugated titanium dioxide nanoparticles in a sustained manner for investigating its osteogenic differentiation potential. To prolong its retention time at the target site, BMP-2 peptide has been conjugated to titanium dioxide nanoparticles owing to its high surface to volume ratio. The effect of biochemical cues from BMP-2 peptide and nanotopographical stimulation of electrospun Zein polydopamine nanofiber were examined for its enhanced osteogenic expression of human fetal osteoblast cells. The sustained delivery of bioactive signals, improved cell adhesion, mineralization, and differentiation could be attributed to its highly interconnected nanofibrous matrix with unique material composition. Further, the expression of osteogenic markers revealed that the fabricated nanofibrous scaffold possess better cell-biomaterial interactions. These promising results demonstrate the potential of the composite nanofibrous scaffold as an effective biomaterial substrate for bone regeneration. Copyright © 2017 John Wiley & Sons, Ltd.

Reconstruction of goat femur segmental defects using triphasic ceramic-coated hydroxyapatite in combination with autologous cells and platelet-rich plasma.

PubMed

Nair, Manitha B; Varma, H K; Menon, K V; Shenoy, Sachin J; John, Annie

2009-06-01

Segmental bone defects resulting from trauma or pathology represent a common and significant clinical problem. In this study, a triphasic ceramic (calcium silicate, hydroxyapatite and tricalcium phosphate)-coated hydroxyapatite (HASi) having the benefits of both HA (osteointegration, osteoconduction) and silica (degradation) was used as a bone substitute for the repair of segmental defect (2 cm) created in a goat femur model. Three experimental goat femur implant groups--(a) bare HASi, (b) osteogenic-induced goat bone marrow-derived mesenchymal stem cells cultured HASi (HASi+C) and (c) osteogenic-induced goat bone marrow-derived mesenchymal stem cells cultured HASi+platelet-rich plasma (HASi+CP)--were designed and efficacy performance in the healing of the defect was evaluated. In all the groups, the material united with host bone without any inflammation and an osseous callus formed around the implant. This reflects the osteoconductivity of HASi where the cells have migrated from the cut ends of host bone. The most observable difference between the groups appeared in the mid region of the defect. In bare HASi groups, numerous osteoblast-like cells could be seen together with a portion of material. However, in HASi+C and HASi+CP, about 60-70% of that area was occupied by woven bone, in line with material degradation. The interconnected porous nature (50-500 microm), together with the chemical composition of the HASi, facilitated the degradation of HASi, thereby opening up void spaces for cellular ingrowth and bone regeneration. The combination of HASi with cells and PRP was an added advantage that could promote the expression of many osteoinductive proteins, leading to faster bone regeneration and material degradation. Based on these results, we conclude that bare HASi can aid in bone regeneration but, with the combination of cells and PRP, the sequence of healing events are much faster in large segmental bone defects in weight-bearing areas in goats.

A 3D printed nano bone matrix for characterization of breast cancer cell and osteoblast interactions

NASA Astrophysics Data System (ADS)

Zhu, Wei; Castro, Nathan J.; Cui, Haitao; Zhou, Xuan; Boualam, Benchaa; McGrane, Robert; Glazer, Robert I.; Zhang, Lijie Grace

2016-08-01

Bone metastasis is one of the most prevalent complications of late-stage breast cancer, in which the native bone matrix components, including osteoblasts, are intimately involved in tumor progression. The development of a successful in vitro model would greatly facilitate understanding the underlying mechanism of breast cancer bone invasion as well as provide a tool for effective discovery of novel therapeutic strategies. In the current study, we fabricated a series of in vitro bone matrices composed of a polyethylene glycol hydrogel and nanocrystalline hydroxyapatite of varying concentrations to mimic the native bone microenvironment for the investigation of breast cancer bone metastasis. A stereolithography-based three-dimensional (3D) printer was used to fabricate the bone matrices with precisely controlled architecture. The interaction between breast cancer cells and osteoblasts was investigated in the optimized bone matrix. Using a Transwell® system to separate the two cell lines, breast cancer cells inhibited osteoblast proliferation, while osteoblasts stimulated breast cancer cell growth, whereas, both cell lines increased IL-8 secretion. Breast cancer cells co-cultured with osteoblasts within the 3D bone matrix formed multi-cellular spheroids in comparison to two-dimensional monolayers. These findings validate the use of our 3D printed bone matrices as an in vitro metastasis model, and highlights their potential for investigating breast cancer bone metastasis.

Alkaline biodegradable implants for osteoporotic bone defects--importance of microenvironment pH.

PubMed

Liu, W; Wang, T; Yang, C; Darvell, B W; Wu, J; Lin, K; Chang, J; Pan, H; Lu, W W

2016-01-01

Change of microenvironment pH by biodegradable implants may ameliorate unbalanced osteoporotic bone remodeling. The present work demonstrated that a weak alkaline condition stimulated osteoblasts differentiation while suppressed osteoclast generation. In vivo, implants with an alkaline microenvironment pH (monitored by a pH microelectrode) exhibited a promising healing effect for the repair of osteoporotic bone defects. Under osteoporotic conditions, the response of the bone microenvironment to an endosseous implant is significantly impaired, and this substantially increases the risk of fracture, non-union and aseptic implant loosening. Acid-base equilibrium is an important factor influencing bone cell behaviour. The present purpose was to study the effect of a series of alkaline biodegradable implant materials on regeneration of osteoporotic bone defect, monitoring the microenvironment pH (μe-pH) over time. The proliferation and differentiation potential of osteoporotic rat bone marrow stromal cells and RAW 264.7 cells were examined under various pH conditions. Ovariectomized rat bone defects were filled with specific biodegradable materials, and μe-pH was measured by pH microelectrode. New osteoid and tartrate-resistant acid phosphatase-positive osteoclast-like cells were examined by Goldner's trichrome and TRAP staining, respectively. The intermediate layer between implants and new bone were studied using energy-dispersive X-ray spectroscopy (EDX) linear scanning. In vitro, weak alkaline conditions stimulated osteoporotic rat bone marrow stromal cells (oBMSC) differentiation, while inhibiting the formation of osteoclasts. In vivo, μe-pH differs from that of the homogeneous peripheral blood and exhibits variations over time particular to each material. Higher initial μe-pH was associated with more new bone formation, late response of TRAP-positive osteoclast-like cells and the development of an intermediate 'apatitic' layer in vivo. EDX suggested that residual material may influence μe-pH even 9 weeks post-surgery. The pH microelectrode is suitable for in vivo μe-pH detection. Alkaline biodegradable materials generate an in vivo microenvironmental pH which is higher than the normal physiological value and show promising healing effects in the context of osteoporotic bone defects.

In vivo outcomes of tissue-engineered osteochondral grafts.

PubMed

Bal, B Sonny; Rahaman, Mohamed N; Jayabalan, Prakash; Kuroki, Keiichi; Cockrell, Mary K; Yao, Jian Q; Cook, James L

2010-04-01

Tissue-engineered osteochondral grafts have been synthesized from a variety of materials, with some success at repairing chondral defects in animal models. We hypothesized that in tissue-engineered osteochondral grafts synthesized by bonding mesenchymal stem cell-loaded hydrogels to a porous material, the choice of the porous scaffold would affect graft healing to host bone, and the quality of cell restoration at the hyaline cartilage surface. Bone marrow-derived allogeneic mesenchymal stem cells were suspended in hydrogels that were attached to cylinders of porous tantalum metal, allograft bone, or a bioactive glass. The tissue-engineered osteochondral grafts, thus created were implanted into experimental defects in rabbit knees. Subchondral bone restoration, defect fill, bone ingrowth-implant integration, and articular tissue quality were compared between the three subchondral materials at 6 and 12 weeks. Bioactive glass and porous tantalum were superior to bone allograft in integrating to adjacent host bone, regenerating hyaline-like tissue at the graft surface, and expressing type II collagen in the articular cartilage.

Three-dimensional co-culture models to study prostate cancer growth, progression, and metastasis to bone.

PubMed

Wang, Ruoxiang; Xu, Jianchun; Juliette, Lisa; Castilleja, Agapito; Love, John; Sung, Shian-Ying; Zhau, Haiyen E; Goodwin, Thomas J; Chung, Leland W K

2005-10-01

Cancer-stromal interaction results in the co-evolution of both the cancer cells and the surrounding host stromal cells. As a consequence of this interaction, cancer cells acquire increased malignant potential and stromal cells become more inductive. In this review we suggest that cancer-stromal interaction can best be investigated by three-dimensional (3D) co-culture models with the results validated by clinical specimens. We showed that 3D culture promoted bone formation in vitro, and explored for the first time, with the help of the astronauts of the Space Shuttle Columbia, the co-culture of human prostate cancer and bone cells to further understand the interactions between these cells. Continued exploration of cancer growth under 3D conditions will rapidly lead to new discoveries and ultimately to improvements in the treatment of men with hormonal refractory prostate cancer.

Interactions between human osteoblasts and prostate cancer cells in a novel 3D in vitro model

PubMed Central

Sieh, Shirly; Lubik, Amy A; Clements, Judith A; Nelson, Colleen C

2010-01-01

Cell-cell and cell-matrix interactions play a major role in tumor morphogenesis and cancer metastasis. Therefore, it is crucial to create a model with a biomimetic microenvironment that allows such interactions to fully represent the pathophysiology of a disease for an in vitro study. This is achievable by using three-dimensional (3D) models instead of conventional two-dimensional (2D) cultures with the aid of tissue engineering technology. We are now able to better address the complex intercellular interactions underlying prostate cancer (CaP) bone metastasis through such models. In this study, we assessed the interaction of CaP cells and human osteoblasts (hOBs) within a tissue engineered bone (TEB) construct. Consistent with other in vivo studies, our findings show that intercellular and CaP cell-bone matrix interactions lead to elevated levels of matrix metalloproteinases, steroidogenic enzymes and the CaP biomarker, prostate specific antigen (PSA); all associated with CaP metastasis. Hence, it highlights the physiological relevance of this model. We believe that this model will provide new insights for understanding of the previously poorly understood molecular mechanisms of bone metastasis, which will foster further translational studies, and ultimately offer a potential tool for drug screening. PMID:21197221

Bone substitute material composition and morphology differentially modulate calcium and phosphate release through osteoclast-like cells.

PubMed

Konermann, A; Staubwasser, M; Dirk, C; Keilig, L; Bourauel, C; Götz, W; Jäger, A; Reichert, C

2014-04-01

The aim of this study was to determine the material composition and cell-mediated remodelling of different calcium phosphate-based bone substitutes. Osteoclasts were cultivated on bone substitutes (Cerabone, Maxresorb, and NanoBone) for up to 5 days. Bafilomycin A1 addition served as the control. To determine cellular activity, the supernatant content of calcium and phosphate was measured by inductively coupled plasma optical emission spectrometry. Cells were visualized on the materials by scanning electron microscopy. Material composition and surface characteristics were assessed by energy-dispersive X-ray spectroscopy. Osteoclast-induced calcium and phosphate release was material-specific. Maxresorb exhibited the highest ion release to the medium (P = 0.034; calcium 40.25mg/l day 5, phosphate 102.08 mg/l day 5) and NanoBone the lowest (P = 0.021; calcium 8.43 mg/l day 5, phosphate 15.15 mg/l day 5); Cerabone was intermediate (P = 0.034; calcium 16.34 mg/l day 5, phosphate 30.6 mg/l day 5). All investigated materials showed unique resorption behaviours. The presented methodology provides a new perspective on the investigation of bone substitute biodegradation, maintaining the material-specific micro- and macrostructure. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Bone Morphogenetic Protein-2 Promotes Human Mesenchymal Stem Cell Survival and Resultant Bone Formation When Entrapped in Photocrosslinked Alginate Hydrogels.

PubMed

Ho, Steve S; Vollmer, Nina L; Refaat, Motasem I; Jeon, Oju; Alsberg, Eben; Lee, Mark A; Leach, J Kent

2016-10-01

There is a substantial need to prolong cell persistence and enhance functionality in situ to enhance cell-based tissue repair. Bone morphogenetic protein-2 (BMP-2) is often used at high concentrations for osteogenic differentiation of mesenchymal stem cells (MSCs) but can induce apoptosis. Biomaterials facilitate the delivery of lower doses of BMP-2, reducing side effects and localizing materials at target sites. Photocrosslinked alginate hydrogels (PAHs) can deliver osteogenic materials to irregular-sized bone defects, providing improved control over material degradation compared to ionically cross-linked hydrogels. It is hypothesized that the delivery of MSCs and BMP-2 from a PAH increases cell persistence by reducing apoptosis, while promoting osteogenic differentiation and enhancing bone formation compared to MSCs in PAHs without BMP-2. BMP-2 significantly decreases apoptosis and enhances survival of photoencapsulated MSCs, while simultaneously promoting osteogenic differentiation in vitro. Bioluminescence imaging reveals increased MSC survival when implanted in BMP-2 PAHs. Bone defects treated with MSCs in BMP-2 PAHs demonstrate 100% union as early as 8 weeks and significantly higher bone volumes at 12 weeks, while defects with MSC-entrapped PAHs alone do not fully bridge. This study demonstrates that transplantation of MSCs with BMP-2 in PAHs achieves robust bone healing, providing a promising platform for bone repair. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Active multilayered capsules for in vivo bone formation

PubMed Central

Facca, S.; Cortez, C.; Mendoza-Palomares, C.; Messadeq, N.; Dierich, A.; Johnston, A. P. R.; Mainard, D.; Voegel, J.-C.; Caruso, F.; Benkirane-Jessel, N.

2010-01-01

Interest in the development of new sources of transplantable materials for the treatment of injury or disease has led to the convergence of tissue engineering with stem cell technology. Bone and joint disorders are expected to benefit from this new technology because of the low self-regenerating capacity of bone matrix secreting cells. Herein, the differentiation of stem cells to bone cells using active multilayered capsules is presented. The capsules are composed of poly-L-glutamic acid and poly-L-lysine with active growth factors embedded into the multilayered film. The bone induction from these active capsules incubated with embryonic stem cells was demonstrated in vitro. Herein, we report the unique demonstration of a multilayered capsule-based delivery system for inducing bone formation in vivo. This strategy is an alternative approach for in vivo bone formation. Strategies using simple chemistry to control complex biological processes would be particularly powerful, as they make production of therapeutic materials simpler and more easily controlled. PMID:20160118

Cyclophilin A (CypA) is associated with the inflammatory infiltration and alveolar bone destruction in an experimental periodontitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Lihua; Li, Chengzhang, E-mail: l56cz@hotmail.com; Department of Periodontology, School and Hospital of Stomatology, Wuhan University, 237 Luo Yu Road, Hongshan District, Wuhan 430079

2010-01-01

Background and objective: CypA is able to regulate inflammatory responses and MMPs production via interaction with its cell surface receptor, EMMPRIN. This study aimed to address the possible association of CypA with pathological inflammation and destruction of periodontal tissues, and whether CypA-EMMPRIN interaction exists in periodontitis. Materials and methods: Experimental periodontitis was induced by ligation according to our previous method. Histological and radiographic examinations were performed. Western blot was used to detect CypA and EMMPRIN expressions in gingival tissues. Immunohistochemistry was applied for CypA, EMMPRIN, MMP-1, MMP-2, MMP-9, as well as cell markers of macrophage, lymphocyte and neutrophil. CypA expression,more » alveolar bone loss, and inflammatory infiltrations were quantified followed by correlation analyses. Results: Western blot revealed that CypA and EMMRPIN expressions were dramatically elevated in inflamed gingival tissues (ligature group) as compared to healthy gingival tissues (control group). The enhanced CypA and EMMPRIN expressions were highly consistent in cell localization on seriate sections. They were permanently co-localized in infiltrating macrophages and lymphocytes, as well as osteoclasts and osteoblasts in interradicular bone, but rarely expressed by infiltrating neutrophils. MMP-1, MMP-2, and MMP-9 expressions were also sharply increased in inflamed gingiva. MMP-2 and MMP-9 were mainly over-expressed by macrophages, while MMP-1 was over-produced by fibroblasts and infiltrating cells. The number of CypA-positive cells was strongly correlated with the ACJ-AC distance (r = 0.839, p = 0.000), the number of macrophages (r = 0.972, p = 0.000), and the number of lymphocytes (r = 0.951, p = 0.000). Conclusion: CypA is associated with the inflammatory infiltration and alveolar bone destruction of periodontitis. CypA-EMMPRIN interaction may exist in these pathological processes.« less

The materials used in bone tissue engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tereshchenko, V. P., E-mail: tervp@ngs.ru; Kirilova, I. A.; Sadovoy, M. A.

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers aremore » the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.« less

Human osteocalcin and bone sialoprotein mediating osteomimicry of prostate cancer cells: role of cAMP-dependent protein kinase A signaling pathway.

PubMed

Huang, Wen-Chin; Xie, Zhihui; Konaka, Hiroyuki; Sodek, Jaro; Zhau, Haiyen E; Chung, Leland W K

2005-03-15

Osteocalcin and bone sialoprotein are the most abundant noncollagenous bone matrix proteins expressed by osteoblasts. Surprisingly, osteocalcin and bone sialoprotein are also expressed by malignant but not normal prostate epithelial cells. The purpose of this study is to investigate how osteocalcin and bone sialoprotein expression is regulated in prostate cancer cells. Our investigation revealed that (a) human osteocalcin and bone sialoprotein promoter activities in an androgen-independent prostate cancer cell line of LNCaP lineage, C4-2B, were markedly enhanced 7- to 12-fold in a concentration-dependent manner by conditioned medium collected from prostate cancer and bone stromal cells. (b) Deletion analysis of human osteocalcin and bone sialoprotein promoter regions identified cyclic AMP (cAMP)-responsive elements (CRE) as the critical determinants for conditioned medium-mediated osteocalcin and bone sialoprotein gene expression in prostate cancer cells. Consistent with these results, the protein kinase A (PKA) pathway activators forskolin and dibutyryl cAMP and the PKA pathway inhibitor H-89, respectively, increased or repressed human osteocalcin and bone sialoprotein promoter activities. (c) Electrophoretic mobility shift assay showed that conditioned medium-mediated stimulation of human osteocalcin and bone sialoprotein promoter activities occurs through increased interaction between CRE and CRE-binding protein. (d) Conditioned medium was found to induce human osteocalcin and bone sialoprotein promoter activities via increased CRE/CRE-binding protein interaction in a cell background-dependent manner, with marked stimulation in selected prostate cancer but not bone stromal cells. Collectively, these results suggest that osteocalcin and bone sialoprotein expression is coordinated and regulated through cAMP-dependent PKA signaling, which may define the molecular basis of the osteomimicry exhibited by prostate cancer cells.

Design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite as a potential bone graft substitute material

NASA Astrophysics Data System (ADS)

Florschutz, Anthony Vatroslav

Utilization of bone grafts for the treatment of skeletal pathology is a common practice in orthopaedic, craniomaxillofacial, dental, and plastic surgery. Autogenous bone graft is the established archetype but has disadvantages including donor site morbidity, limited supply, and prolonging operative time. In order to avoid these and other issues, bone graft substitute materials are becoming increasingly prevalent among surgeons for reconstructing skeletal defects and arthrodesis applications. Bone graft substitutes are biomaterials, biologics, and guided tissue/bone regenerative devices that can be used alone or in combinations as supplements or alternatives to autogenous bone graft. There is a growing interest and trend to specialize graft substitutes for specific indications and although there is good rationale for this indication-specific approach, the development and utility of a more universal bone graft substitute may provide a better answer for patients and surgeons. The aim of the present research focuses on the design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite composites for potential use as a bone graft substitutes. After initial establishment of rational material design, gelatinhydroxyapatite scaffolds were fabricated with different gelatin:hydroxyapatite ratios and crosslinking concentrations. The synthesized scaffolds were subsequently evaluated on the basis of their swelling behavior, porosity, density, percent composition, mechanical properties, and morphology and further assessed with respect to cell-biomaterial interaction and biomineralization in vitro. Although none of the materials achieved mechanical properties suitable for structural graft applications, a reproducible material design and synthesis was achieved with properties recognized to facilitate bone formation. Select scaffold formulations as well as a subset of scaffolds loaded with recombinant human bone morphogenetic protein-2 were implanted ectopically in a rodent animal model and histologically evaluated for biocompatibility, degradation, and bone formation in vivo. The gelatin-hydroxyapatite scaffolds retained dimensional structure over 28 days and did not elicit any undesirable systemic or local effects. Distinct areas of mineralization and osteoid/bone were noted in all the implanted scaffolds and quantitative differences were primarily dependent on the presence of hydroxyapatite.

Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones.

PubMed

Ignjatović, Nenad; Ajduković, Zorica; Savić, Vojin; Najman, Stevo; Mihailović, Dragan; Vasiljević, Perica; Stojanović, Zoran; Uskoković, Vuk; Uskoković, Dragan

2013-02-01

Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of 6 months after the implantation of the material containing different amounts of cobalt, ranging from 5 to 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study.

Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones

PubMed Central

Ignjatović, Nenad; Ajduković, Zorica; Savić, Vojin; Najman, Stevo; Mihailović, Dragan; Vasiljević, Perica; Stojanović, Zoran; Uskoković, Vuk; Uskoković, Dragan

2012-01-01

Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of six months after the implantation of the material containing different amounts of cobalt, ranging from 5 – 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study. PMID:23090835

Is Graphene a Promising Nano-Material for Promoting Surface Modification of Implants or Scaffold Materials in Bone Tissue Engineering?

PubMed Central

Gu, Ming; Liu, Yunsong; Chen, Tong; Du, Feng; Zhao, Xianghui; Xiong, Chunyang

2014-01-01

Bone tissue engineering promises to restore bone defects that are caused by severe trauma, congenital malformations, tumors, and nonunion fractures. How to effectively promote the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) or seed cells has become a hot topic in this field. Many researchers are studying the ways of conferring a pro-osteodifferentiation or osteoinductive capability on implants or scaffold materials, where osteogenesis of seed cells is promoted. Graphene (G) provides a new kind of coating material that may confer the pro-osteodifferentiation capability on implants and scaffold materials by surface modification. Here, we review recent studies on the effects of graphene on surface modifications of implants or scaffold materials. The ability of graphene to improve the mechanical and biological properties of implants or scaffold materials, such as nitinol and carbon nanotubes, and its ability to promote the adhesion, proliferation, and osteogenic differentiation of MSCs or osteoblasts have been demonstrated in several studies. Most previous studies were performed in vitro, but further studies will explore the mechanisms of graphene's effects on bone regeneration, its in vivo biocompatibility, its ability to promote osteodifferentiation, and its potential applications in bone tissue engineering. PMID:24447041

Is graphene a promising nano-material for promoting surface modification of implants or scaffold materials in bone tissue engineering?

PubMed

Gu, Ming; Liu, Yunsong; Chen, Tong; Du, Feng; Zhao, Xianghui; Xiong, Chunyang; Zhou, Yongsheng

2014-10-01

Bone tissue engineering promises to restore bone defects that are caused by severe trauma, congenital malformations, tumors, and nonunion fractures. How to effectively promote the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) or seed cells has become a hot topic in this field. Many researchers are studying the ways of conferring a pro-osteodifferentiation or osteoinductive capability on implants or scaffold materials, where osteogenesis of seed cells is promoted. Graphene (G) provides a new kind of coating material that may confer the pro-osteodifferentiation capability on implants and scaffold materials by surface modification. Here, we review recent studies on the effects of graphene on surface modifications of implants or scaffold materials. The ability of graphene to improve the mechanical and biological properties of implants or scaffold materials, such as nitinol and carbon nanotubes, and its ability to promote the adhesion, proliferation, and osteogenic differentiation of MSCs or osteoblasts have been demonstrated in several studies. Most previous studies were performed in vitro, but further studies will explore the mechanisms of graphene's effects on bone regeneration, its in vivo biocompatibility, its ability to promote osteodifferentiation, and its potential applications in bone tissue engineering.

Infection of orthopedic implants with emphasis on bacterial adhesion process and techniques used in studying bacterial-material interactions

PubMed Central

Ribeiro, Marta; Monteiro, Fernando J.; Ferraz, Maria P.

2012-01-01

Staphylococcus comprises up to two-thirds of all pathogens in orthopedic implant infections and they are the principal causative agents of two major types of infection affecting bone: septic arthritis and osteomyelitis, which involve the inflammatory destruction of joint and bone. Bacterial adhesion is the first and most important step in implant infection. It is a complex process influenced by environmental factors, bacterial properties, material surface properties and by the presence of serum or tissue proteins. Properties of the substrate, such as chemical composition of the material, surface charge, hydrophobicity, surface roughness and the presence of specific proteins at the surface, are all thought to be important in the initial cell attachment process. The biofilm mode of growth of infecting bacteria on an implant surface protects the organisms from the host immune system and antibiotic therapy. The research for novel therapeutic strategies is incited by the emergence of antibiotic-resistant bacteria. This work will provide an overview of the mechanisms and factors involved in bacterial adhesion, the techniques that are currently being used studying bacterial-material interactions as well as provide insight into future directions in the field. PMID:23507884

Induction of experimental bone metastasis in mice by transfection of integrin alpha 4 beta 1 into tumor cells.

PubMed Central

Matsuura, N.; Puzon-McLaughlin, W.; Irie, A.; Morikawa, Y.; Kakudo, K.; Takada, Y.

1996-01-01

Cell adhesion receptors (eg, integrins and CD44) play an important role in invasion and metastasis during tumor progression. The increase in integrin alpha 4 beta 1 expression on primary melanomas has been reported to significantly correlate with the development of metastases. alpha 4 beta 1 is a cell surface heterodimer that mediates cell-cell and cell-extracellular matrix interactions through adhesion to vascular cell adhesion molecule (VCAM)-1 and to the IIICS region of fibronectin. To test the effects of alpha 4 beta 1 expression on tumor cell metastasis, Chinese hamster ovary cells were transfected with human alpha 4 cDNA. Whereas alpha 4-negative Chinese hamster ovary cells developed only pulmonary metastasis, alpha 4-positive Chinese hamster ovary cells developed bone and pulmonary metastasis in 3 to 4 weeks when injected intravenously into nude mice. Bone metastasis was inhibited by antibody against alpha 4 or VCAM-1. Expression of alpha 3 beta 1, alpha 6 beta 1, or alpha V beta 1 did not induce bone metastasis. Expression of alpha 4 beta 1 also induced bone metastasis in K562 human erythroleukemia cells injected into SCID mice. These results demonstrate that alpha 4 beta 1 can induce tumor cell trafficking to bone, probably via interaction with VCAM-1 that is constitutively expressed on bone marrow stromal cells. Images Figure 1 Figure 3 PMID:8546226

The control of human mesenchymal cell differentiation using nanoscale symmetry and disorder

NASA Astrophysics Data System (ADS)

Dalby, Matthew J.; Gadegaard, Nikolaj; Tare, Rahul; Andar, Abhay; Riehle, Mathis O.; Herzyk, Pawel; Wilkinson, Chris D. W.; Oreffo, Richard O. C.

2007-12-01

A key tenet of bone tissue engineering is the development of scaffold materials that can stimulate stem cell differentiation in the absence of chemical treatment to become osteoblasts without compromising material properties. At present, conventional implant materials fail owing to encapsulation by soft tissue, rather than direct bone bonding. Here, we demonstrate the use of nanoscale disorder to stimulate human mesenchymal stem cells (MSCs) to produce bone mineral in vitro, in the absence of osteogenic supplements. This approach has similar efficiency to that of cells cultured with osteogenic media. In addition, the current studies show that topographically treated MSCs have a distinct differentiation profile compared with those treated with osteogenic media, which has implications for cell therapies.

Osteoimmunology: The Conceptual Framework Unifying the Immune and Skeletal Systems.

PubMed

Okamoto, Kazuo; Nakashima, Tomoki; Shinohara, Masahiro; Negishi-Koga, Takako; Komatsu, Noriko; Terashima, Asuka; Sawa, Shinichiro; Nitta, Takeshi; Takayanagi, Hiroshi

2017-10-01

The immune and skeletal systems share a variety of molecules, including cytokines, chemokines, hormones, receptors, and transcription factors. Bone cells interact with immune cells under physiological and pathological conditions. Osteoimmunology was created as a new interdisciplinary field in large part to highlight the shared molecules and reciprocal interactions between the two systems in both heath and disease. Receptor activator of NF-κB ligand (RANKL) plays an essential role not only in the development of immune organs and bones, but also in autoimmune diseases affecting bone, thus effectively comprising the molecule that links the two systems. Here we review the function, gene regulation, and signal transduction of osteoimmune molecules, including RANKL, in the context of osteoclastogenesis as well as multiple other regulatory functions. Osteoimmunology has become indispensable for understanding the pathogenesis of a number of diseases such as rheumatoid arthritis (RA). We review the various osteoimmune pathologies, including the bone destruction in RA, in which pathogenic helper T cell subsets [such as IL-17-expressing helper T (Th17) cells] induce bone erosion through aberrant RANKL expression. We also focus on cellular interactions and the identification of the communication factors in the bone marrow, discussing the contribution of bone cells to the maintenance and regulation of hematopoietic stem and progenitors cells. Thus the time has come for a basic reappraisal of the framework for understanding both the immune and bone systems. The concept of a unified osteoimmune system will be absolutely indispensable for basic and translational approaches to diseases related to bone and/or the immune system. Copyright © 2017 the American Physiological Society.

A Spontaneous 3D Bone-On-a-Chip for Bone Metastasis Study of Breast Cancer Cells.

PubMed

Hao, Sijie; Ha, Laura; Cheng, Gong; Wan, Yuan; Xia, Yiqiu; Sosnoski, Donna M; Mastro, Andrea M; Zheng, Si-Yang

2018-03-01

Bone metastasis occurs at ≈70% frequency in metastatic breast cancer. The mechanisms used by tumors to hijack the skeleton, promote bone metastases, and confer therapeutic resistance are poorly understood. This has led to the development of various bone models to investigate the interactions between cancer cells and host bone marrow cells and related physiological changes. However, it is challenging to perform bone studies due to the difficulty in periodic sampling. Herein, a bone-on-a-chip (BC) is reported for spontaneous growth of a 3D, mineralized, collagenous bone tissue. Mature osteoblastic tissue of up to 85 µm thickness containing heavily mineralized collagen fibers naturally formed in 720 h without the aid of differentiation agents. Moreover, co-culture of metastatic breast cancer cells is examined with osteoblastic tissues. The new bone-on-a-chip design not only increases experimental throughput by miniaturization, but also maximizes the chances of cancer cell interaction with bone matrix of a concentrated surface area and facilitates easy, frequent observation. As a result, unique hallmarks of breast cancer bone colonization, previously confirmed only in vivo, are observed. The spontaneous 3D BC keeps the promise as a physiologically relevant model for the in vitro study of breast cancer bone metastasis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid prototyped porous nickel–titanium scaffolds as bone substitutes

PubMed Central

Hoffmann, Waldemar; Bormann, Therese; Rossi, Antonella; Müller, Bert; Schumacher, Ralf; Martin, Ivan; Wendt, David

2014-01-01

While calcium phosphate–based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel–titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel–titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel–titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel–titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel–titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel–titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold’s pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel–titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium. PMID:25383165

Foreign Body Giant Cell-Related Encapsulation of a Synthetic Material Three Years After Augmentation.

PubMed

Lorenz, Jonas; Barbeck, Mike; Sader, Robert A; Kirkpatrick, Charles J; Russe, Philippe; Choukroun, Joseph; Ghanaati, Shahram

2016-06-01

Bone substitute materials of different origin and chemical compositions are frequently used in augmentation procedures to enlarge the local bone amount. However, relatively little data exist on the long-term tissue reactions. The presented case reports for the first time histological and histomorphometrical analyses of a nanocrystaline hydroxyapatite-based bone substitute material implanted in the human sinus cavity after an integration period of 3 years. The extracted biopsy was analyzed histologically and histomorphometrically with focus on the tissue reactions, vascularization, new bone formation, and the induction of a foreign body reaction. A comparably high rate of connective tissue (48.25%) surrounding the remaining bone substitute granules (42.13%) was observed. Accordingly, the amount of bone tissue (9.62%) built the smallest fraction within the biopsy. Further, tartrate-resistant acid phosphatase-positive and -negative multinucleated giant cells (4.35 and 3.93 cells/mm(2), respectively) were detected on the material-tissue interfaces. The implantation bed showed a mild vascularization of 10.03 vessels/mm(2) and 0.78%. The present case report shows that after 3 years, a comparable small amount of bone tissue was observable. Thus, the foreign body response to the bone substitute seems to be folded without further degradation or regeneration.

Bone-Inspired Spatially Specific Piezoelectricity Induces Bone Regeneration

PubMed Central

Yu, Peng; Ning, Chengyun; Zhang, Yu; Tan, Guoxin; Lin, Zefeng; Liu, Shaoxiang; Wang, Xiaolan; Yang, Haoqi; Li, Kang; Yi, Xin; Zhu, Ye; Mao, Chuanbin

2017-01-01

The extracellular matrix of bone can be pictured as a material made of parallel interspersed domains of fibrous piezoelectric collagenous materials and non-piezoelectric non-collagenous materials. To mimic this feature for enhanced bone regeneration, a material made of two parallel interspersed domains, with higher and lower piezoelectricity, respectively, is constructed to form microscale piezoelectric zones (MPZs). The MPZs are produced using a versatile and effective laser-irradiation technique in which K0.5Na0.5NbO3 (KNN) ceramics are selectively irradiated to achieve microzone phase transitions. The phase structure of the laser-irradiated microzones is changed from a mixture of orthorhombic and tetragonal phases (with higher piezoelectricity) to a tetragonal dominant phase (with lower piezoelectricity). The microzoned piezoelectricity distribution results in spatially specific surface charge distribution, enabling the MPZs to bear bone-like microscale electric cues. Hence, the MPZs induce osteogenic differentiation of stem cells in vitro and bone regeneration in vivo even without being seeded with stem cells. The concept of mimicking the spatially specific piezoelectricity in bone will facilitate future research on the rational design of tissue regenerative materials. PMID:28900517

Enhanced osteoblast adhesion on nanostructured selenium compacts for anti-cancer orthopedic applications.

PubMed

Tran, Phong; Webster, Thomas J

2008-01-01

Metallic bone implants possess numerous problems limiting their long-term efficacy, such as poor prolonged osseointegration, stress shielding, and corrosion under in vivo environments. Such problems are compounded for bone cancer patients since numerous patients receive orthopedic implants after cancerous bone resection. Unfortunately, current orthopedic materials were not originally developed to simultaneously increase healthy bone growth (as in traditional orthopedic implant applications) while inhibiting cancerous bone growth. The long-term objective of the present research is to investigate the use of nano-rough selenium to prevent bone cancer from re-occurring while promoting healthy bone growth for this select group of cancer patients. Selenium is a well known anti-cancer chemical. However, what is not known is how healthy bone cells interact with selenium. To determine this, selenium, spherical or semispherical shots, were pressed into cylindrical compacts and these compacts were then etched using 1N NaOH to obtain various surface structures ranging from the micron, submicron to nano scales. Changes in surface chemistry were also analyzed. Through these etching techniques, results of this study showed that biologically inspired surface roughness values were created on selenium compacts to match that of natural bone roughness. Moreover, results showed that healthy bone cell adhesion increased with greater nanometer selenium roughness (more closely matching that of titanium). In this manner, this study suggests that nano-rough selenium should be further tested for orthopedic applications involving bone cancer treatment.

Enhanced osteoblast adhesion on nanostructured selenium compacts for anti-cancer orthopedic applications

PubMed Central

Tran, Phong; Webster, Thomas J

2008-01-01

Metallic bone implants possess numerous problems limiting their long-term efficacy, such as poor prolonged osseointegration, stress shielding, and corrosion under in vivo environments. Such problems are compounded for bone cancer patients since numerous patients receive orthopedic implants after cancerous bone resection. Unfortunately, current orthopedic materials were not originally developed to simultaneously increase healthy bone growth (as in traditional orthopedic implant applications) while inhibiting cancerous bone growth. The long-term objective of the present research is to investigate the use of nano-rough selenium to prevent bone cancer from re-occurring while promoting healthy bone growth for this select group of cancer patients. Selenium is a well known anti-cancer chemical. However, what is not known is how healthy bone cells interact with selenium. To determine this, selenium, spherical or semispherical shots, were pressed into cylindrical compacts and these compacts were then etched using 1N NaOH to obtain various surface structures ranging from the micron, submicron to nano scales. Changes in surface chemistry were also analyzed. Through these etching techniques, results of this study showed that biologically inspired surface roughness values were created on selenium compacts to match that of natural bone roughness. Moreover, results showed that healthy bone cell adhesion increased with greater nanometer selenium roughness (more closely matching that of titanium). In this manner, this study suggests that nano-rough selenium should be further tested for orthopedic applications involving bone cancer treatment. PMID:18990948

HA and double-layer HA-P2O5/CaO glass coatings: influence of chemical composition on human bone marrow cells osteoblastic behavior.

PubMed

Ferraz, M P; Fernandes, M H; Santos, J D; Monteiro, F J

2001-07-01

Human osteoblastic bone marrow derived cells were cultured for 28 days onto the surface of a glass reinforced hydroxyapatite (HA) composite and a commercial type HA plasma sprayed coatings, both in the "as-received" condition and after an immersion treatment with culture medium during 21 days. Cell proliferation and differentiation were analyzed as a function of the chemical composition of the coatings and the immersion treatment. Cell attachment, growth and differentiation of osteoblastic bone marrow cells seeded onto "as-received" plasma sprayed coatings were strongly affected by the time-dependent variation of the surface structure occurring during the first hours of culture. Initial interactions leading to higher amounts of adsorbed protein and zeta potential shifts towards negative charges appeared to result in surface structures with better biological performance. Cultures grown onto the pretreated coatings showed higher rate of cell proliferation and increased functional activity, as compared to those grown onto the corresponding "as-received" materials. However, the cell behavior was similar in the glass composite and HA coatings. The results showed that the glass composites present better characteristics for bone cell growth and function than HA. In addition, this work also provide evidence that the biological performance of the glass composites can be modulated and improved by manipulations in the chemical composition, namely in the content of glass added to HA. Copyright 2001 Kluwer Academic Publishers

Study of surface phenomena in biomaterials: The influence of physical factors

NASA Astrophysics Data System (ADS)

Sachelarie, Liliana; Vasiliu, Mihaela Papusa; Ciobanu, Catalina

2015-10-01

This study's purpose is pointing out the phenomenon that occurs at time of interaction between the tissue with implant. The materials used are Ti and its alloys. The oral tissue must be compatible with the materials used in surgical implant to human body. The bio-materials surface behavior is influenced by physical characteristics. The methods we use show a number of bio-compatibility aspects. The success of an implant in a hard tissue depends not only on the initial attachment and the osteogenic cells consecutive proliferation, but also on their capacity to create a new bone.

Osteoclastic differentiation and resorption is modulated by bioactive metal ions Co2+, Cu2+ and Cr3+ incorporated into calcium phosphate bone cements.

PubMed

Bernhardt, Anne; Schamel, Martha; Gbureck, Uwe; Gelinsky, Michael

2017-01-01

Biologically active metal ions in low doses have the potential to accelerate bone defect healing. For successful remodelling the interaction of bone graft materials with both bone-forming osteoblasts and bone resorbing osteoclasts is crucial. In the present study brushite forming calcium phosphate cements (CPC) were doped with Co2+, Cu2+ and Cr3+ and the influence of these materials on osteoclast differentiation and activity was examined. Human osteoclasts were differentiated from human peripheral blood mononuclear cells (PBMC) both on the surface and in indirect contact to the materials on dentin discs. Release of calcium, phosphate and bioactive metal ions was determined using ICP-MS both in the presence and absence of the cells. While Co2+ and Cu2+ showed a burst release, Cr3+ was released steadily at very low concentrations (below 1 μM) and both calcium and phosphate release of the cements was considerably changed in the Cr3+ modified samples. Direct cultivation of PBMC/osteoclasts on Co2+ cements showed lower attached cell number compared to the reference but high activity of osteoclast specific enzymes tartrate resistant acid phosphatase (TRAP), carbonic anhydrase II (CAII) and cathepsin K (CTSK) and significantly increased gene expression of vitronectin receptor. Indirect cultivation with diluted Co2+ cement extracts revealed highest resorbed area compared to all other modifications and the reference. Cu2+ cements had cytotoxic effect on PBMC/osteoclasts during direct cultivation, while indirect cultivation with diluted extracts from Cu2+ cements did not provoke cytotoxic effects but a strictly inhibited resorption. Cr3+ doped cements did not show cytotoxic effects at all. Gene expression and enzyme activity of CTSK was significantly increased in direct culture. Indirect cultivation with Cr3+ doped cements revealed significantly higher resorbed area compared to the reference. In conclusion Cr3+ doped calcium phosphate cements are an innovative cement modification because of their high cytocompatibility and support of active resorption by osteoclasts.

Adhesive interactions of human multiple myeloma cell lines with different extracellular matrix molecules.

PubMed

Kibler, C; Schermutzki, F; Waller, H D; Timpl, R; Müller, C A; Klein, G

1998-06-01

Multiple myeloma represents a human B cell malignancy which is characterized by a predominant localization of the malignant cell clone within the bone marrow. With the exception of the terminal stage of the disease the myeloma tumor cells do not circulate in the peripheral blood. The bone marrow microenvironment is believed to play an important role in homing, proliferation and terminal differentiation of myeloma cells. Here we have studied the expression of several extracellular matrix (ECM) molecules in the bone marrow of multiple myeloma patients and analyzed their adhesive capacities with four different human myeloma-derived cell lines. All ECM molecules analyzed (tenascin, laminin, fibronectin, collagen types I, III, V and VI) could be detected in bone marrow cryostat sections of multiple myeloma patients. Adhesion assays showed that only laminin, the microfibrillar collagen type VI and fibronectin were strong adhesive components for the myeloma cell lines U266, IM-9, OPM-2 and NCI-H929. Tenascin and collagen type I were only weak adhesive substrates for these myeloma cells. Adhesion to laminin and fibronectin was beta 1-integrin-mediated since addition of anti-beta 1-integrin antibodies could inhibit the binding of the four different cell types to both matrix molecules. In contrast, integrins do not seem to be involved in binding of the myeloma cells to collagen type VI. Instead, inhibition of binding by heparin suggested that membrane-bound heparan sulfate proteoglycans are responsible ligands for binding to collagen type VI. Adhesion assays with several B-cell lines resembling earlier differentiation stages revealed only weak interactions with tenascin and no interactions with collagen type VI, laminin or fibronectin. In summary, the interactions of human myeloma cells with the extracellular matrix may explain the specific retention of the plasma cells within the bone marrow.

'Universal' microstructural patterns in cortical and trabecular, extracellular and extravascular bone materials: micromechanics-based prediction of anisotropic elasticity.

PubMed

Fritsch, Andreas; Hellmich, Christian

2007-02-21

Bone materials are characterized by an astonishing variability and diversity. Still, because of 'architectural constraints' due to once chosen material constituents and their physical interaction, the fundamental hierarchical organization or basic building plans of bone materials remain largely unchanged during biological evolution. Such universal patterns of microstructural organization govern the mechanical interaction of the elementary components of bone (hydroxyapatite, collagen, water; with directly measurable tissue-independent elastic properties), which are here quantified through a multiscale homogenization scheme delivering effective elastic properties of bone materials: at a scale of 10nm, long cylindrical collagen molecules, attached to each other at their ends by approximately 1.5nm long crosslinks and hosting intermolecular water inbetween, form a contiguous matrix called wet collagen. At a scale of several hundred nanometers, wet collagen and mineral crystal agglomerations interpenetrate each other, forming the mineralized fibril. At a scale of 5-10microm, the extracellular solid bone matrix is represented as collagen fibril inclusions embedded in a foam of largely disordered (extrafibrillar) mineral crystals. At a scale above the ultrastructure, where lacunae are embedded in extracellular bone matrix, the extravascular bone material is observed. Model estimates predicted from tissue-specific composition data gained from a multitude of chemical and physical tests agree remarkably well with corresponding acoustic stiffness experiments across a variety of cortical and trabecular, extracellular and extravascular materials. Besides from reconciling the well-documented, seemingly opposed concepts of 'mineral-reinforced collagen matrix' and 'collagen-reinforced mineral matrix' for bone ultrastructure, this approach opens new possibilities in the exploitation of computer tomographic data for nano-to-macro mechanics of bone organs.

Synthetic bone substitute material comparable with xenogeneic material for bone tissue regeneration in oral cancer patients: First and preliminary histological, histomorphometrical and clinical results.

PubMed

Ghanaati, Shahram; Barbeck, Mike; Lorenz, Jonas; Stuebinger, Stefan; Seitz, Oliver; Landes, Constantin; Kovács, Adorján F; Kirkpatrick, Charles J; Sader, Robert A

2013-07-01

The present study was first to evaluate the material-specific cellular tissue response of patients with head and neck cancer to a nanocrystalline hydroxyapatite bone substitute NanoBone (NB) in comparison with a deproteinized bovine bone matrix Bio-Oss (BO) after implantation into the sinus cavity. Eight patients with tumor resection for oral cancer and severely resorbed maxillary bone received materials according to a split mouth design for 6 months. Bone cores were harvested prior to implantation and analyzed histologically and histomorphometrically. Implant survival was followed-up to 2 years after placement. Histologically, NB underwent a higher vascularization and induced significantly more tartrate-resistant acid phosphatase-positive (TRAP-positive) multinucleated giant cells when compared with BO, which induced mainly mononuclear cells. No significant difference was observed in the extent of new bone formation between both groups. The clinical follow-up showed undisturbed healing of all implants in the BO-group, whereas the loss of one implant was observed in the NB-group. Within its limits, the present study showed for the first time that both material classes evaluated, despite their induction of different cellular tissue reactions, may be useful as augmentation materials for dental and maxillofacial surgical applications, particularly in patients who previously had oral cancer.

Micro-Nanostructures of Cellulose-Collagen for Critical Sized Bone Defect Healing.

PubMed

Aravamudhan, Aja; Ramos, Daisy M; Nip, Jonathan; Kalajzic, Ivo; Kumbar, Sangamesh G

2018-02-01

Bone tissue engineering strategies utilize biodegradable polymeric matrices alone or in combination with cells and factors to provide mechanical support to bone, while promoting cell proliferation, differentiation, and tissue ingrowth. The performance of mechanically competent, micro-nanostructured polymeric matrices, in combination with bone marrow stromal cells (BMSCs), is evaluated in a critical sized bone defect. Cellulose acetate (CA) is used to fabricate a porous microstructured matrix. Type I collagen is then allowed to self-assemble on these microstructures to create a natural polymer-based, micro-nanostructured matrix (CAc). Poly (lactic-co-glycolic acid) matrices with identical microstructures serve as controls. Significantly higher number of implanted host cells are distributed in the natural polymer based micro-nanostructures with greater bone density and more uniform cell distribution. Additionally, a twofold increase in collagen content is observed with natural polymer based scaffolds. This study establishes the benefits of natural polymer derived micro-nanostructures in combination with donor derived BMSCs to repair and regenerate critical sized bone defects. Natural polymer based materials with mechanically competent micro-nanostructures may serve as an alternative material platform for bone regeneration. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compositos CNTs/bioceramico para a estimulacao eletrica ossea in situ

NASA Astrophysics Data System (ADS)

Mata, Diogo Miguel Rodrigues Marinho da

The present thesis aims to develop a biocompatible and electroconductor bone graft containing carbon nanotubes (CNTs) that allows the in situ regeneration of bone cells by applying pulsed external electrical stimuli. The CNTs were produced by chemical vapor deposition (CVD) by a semi-continuous method with a yield of 500 mg/day. The deposition parameters were optimised to obtain high pure CNTs 99.96% with controlled morphologies, fundamental requisites for the biomedical application under study. The chemical functionalisation of CNTs was also optimised to maximise their processability and biocompatibility. The CNTs were functionalised by the Diels-Alder cycloaddition of 1,3-butadiene. The biological behaviour of the functionalised CNTs was evaluated in vitro with the osteoblastic cells line MG63 and in vivo, by subcutaneous implantation in rats. The materials did not induce an expressed inflammatory response, but the functionalised CNTs showed a superior in vitro and in vivo biocompatibility than the non-functionalised ones. Composites of ceramic matrix, of bioglass (Glass) and hydroxyapatite (HA), reinforced with carbon nanotubes (CNT/Glass/HA) were processed by a wet approach. The incorporation of just 4.4 vol% of CNTs allowed the increase of 10 orders of magnitude of the electrical conductivity of the matrix. In vitro studies with MG63 cells show that the CNT/Glass/HA composites guarantee the adhesion and proliferation of bone cells, and stimulate their phenotype expression, namely the alkaline phosphate (ALP). The interactions between the composite materials and the culture medium (α-MEM), under an applied electrical external field, were studied by scanning vibrating electrode technique. An increase of the culture medium electrical conductivity and the electrical field confinement in the presence of the conductive samples submerged in the medium was demonstrated. The in vitro electrical stimulation of MG63 cells on the conductive composites promotes the increase of the cell metabolic activity and DNA content by 130% and 60%, relatively to the non-stimulated condition, after only 3 days of daily stimulation of 15 μA for 15 min. Moreover, the osteoblastic gene expression for Runx2, osteocalcin (OC) and ALP was enhanced by 80%, 50% and 25%, after 5 days of stimulation. Instead, for dielectric materials, the stimulus delivering was less efficient, giving an equal or lower cellular response than the non-stimulated condition. The proposed electroconductive bone grafts offer exciting possibilities in bone regeneration strategies by delivering in situ electrical stimulus to cells and consequent control of the new bone tissue formation rate. It is expected that conductive smart biomaterials might turn the selective bone electrotherapy of clinical relevance by decreasing the postoperative healing times.

Biological effectiveness of nuclear fragments produced by high-energy protons interacting in tissues near the bone- soft tissue interface

NASA Astrophysics Data System (ADS)

Shavers, Mark Randall

1999-12-01

High-energy protons in the galactic cosmic rays (GCR)-or generated by nuclear interactions of GCR heavy-ions with material-are capable of penetrating great thicknesses of shielding to irradiate humans in spacecraft or in lunar or Martian habitats. As protons interact with the nuclei of the elemental constituents of soft tissue and bone, low energy nuclei-target fragments-are emitted into the cells responsible for bone development and maintenance and for hematopoiesis. Leukemogenesis is the principal endpoint of concern because it is the most likely deleterious effect, and it has a short latency period and comparatively low survival rate, although other myelo- proliferative disorders and osteosarcoma also may be induced. A one-dimensional proton-target fragment transport model was used to calculate the energy spectra of fragments produced in bone and soft tissue, and present in marrow cavities at distances from a bone interface. In terms of dose equivalent, the target fragments are as significant as the incident protons. An average radiation quality factor was found to be between 1.8 and 2.6. Biological response to the highly non- uniform energy deposition of the target fragments is such that an alternative approach to conventional predictive risk assessment is needed. Alternative procedures are presented. In vitro cell response and relative biological effectiveness were calculated from the radial dose distribution of each fragment produced by 1-GeV protons using parameters of a modified Ion-Gamma- Kill (IGK) model of radiation action. The modelled endpoints were survival of C3H10t 1/2 and V79 cells, neoplastic transformation of C3H10t1/2 cells, and mutation of the X-linked hypoxanthine phosphoribosyltransferase (HPRT) locus in V79 cells. The dose equivalent and cell responses increased by 10% or less near the interface. Since RBE increases with decreasing dose in the IGK model, comparisons with quality factors were made at dose levels 0.01 <= D [Gy] <= 2. Applying average quality factors derived herein to GCR exposures results in a <= 5% increase of in average quality. Calculated RBEs indicate that accepted quality factors for high-energy protons may be too low due to the relatively high effectiveness of the low-charged target fragments. Derived RBEs for target fragments increase the calculated biological effectiveness of GCR by 20% to 180%.

Cellular Therapy to Obtain Rapid Endochondral Bone Formation

DTIC Science & Technology

2012-03-01

biological information and involves the development of a novel biomaterial that can safely house the cells expressing the bone inductive factor to... produce the new bone at which time the material is then selectively eliminated. Ultimately this system has significant applicability. Often bone graft must...hypothesis will provide a safe and efficacious material for the production of bone leading to reliable fracture healing, circumventing the need for

Synthetic bone substitute material comparable with xenogeneic material for bone tissue regeneration in oral cancer patients: First and preliminary histological, histomorphometrical and clinical results

PubMed Central

Ghanaati, Shahram; Barbeck, Mike; Lorenz, Jonas; Stuebinger, Stefan; Seitz, Oliver; Landes, Constantin; Kovács, Adorján F.; Kirkpatrick, Charles J.; Sader, Robert A.

2013-01-01

Background: The present study was first to evaluate the material-specific cellular tissue response of patients with head and neck cancer to a nanocrystalline hydroxyapatite bone substitute NanoBone (NB) in comparison with a deproteinized bovine bone matrix Bio-Oss (BO) after implantation into the sinus cavity. Materials and Methods: Eight patients with tumor resection for oral cancer and severely resorbed maxillary bone received materials according to a split mouth design for 6 months. Bone cores were harvested prior to implantation and analyzed histologically and histomorphometrically. Implant survival was followed-up to 2 years after placement. Results: Histologically, NB underwent a higher vascularization and induced significantly more tartrate-resistant acid phosphatase-positive (TRAP-positive) multinucleated giant cells when compared with BO, which induced mainly mononuclear cells. No significant difference was observed in the extent of new bone formation between both groups. The clinical follow-up showed undisturbed healing of all implants in the BO-group, whereas the loss of one implant was observed in the NB-group. Conclusions: Within its limits, the present study showed for the first time that both material classes evaluated, despite their induction of different cellular tissue reactions, may be useful as augmentation materials for dental and maxillofacial surgical applications, particularly in patients who previously had oral cancer. PMID:24205471

Human bone marrow-derived MSCs can home to orthotopic breast cancer tumors and promote bone metastasis

PubMed Central

Goldstein, Robert H; Reagan, Michaela R; Anderson, Kristen; Kaplan, David L; Rosenblatt, Michael

2010-01-01

American women have a nearly 25% lifetime risk of developing breast cancer, with 20–40% of these patients developing life-threatening metastases. Over 70% of patients presenting with metastases have skeletal involvement, which signals progression to an incurable stage. Tumor-stroma cell interactions are only superficially understood, specifically regarding the ability of stromal cells to affect metastasis. In vivo models show that exogenously supplied hBMSCs (human bone-marrow derived stem cells) migrate to breast cancer tumors, but no reports have shown endogenous hBMSC migration from the bone to primary tumors. Here we present a model of in vivo hBMSC migration from a physiologic human bone environment to human breast tumors. Further, hBMSCs alter tumor growth and bone metastasis frequency. hBMSCs may home to certain breast tumors based on tumor-derived TGF-β1. Moreover, at the primary tumor IL-17B/IL-17BR signaling may mediate interactions between hBMSCs and breast cancer cells (BCCs). PMID:21159629

[Effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterial on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells].

PubMed

Li, Jingfeng; Zheng, Qixin; Guo, Xiaodong; Chen, Liaobin

2014-10-01

In the present research, the effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterials on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells were investigated. The experiments were divided into three groups due to biomaterials used: Group A (composite materials of sintered bone modified with surface mineralization and P24, a peptide of bone morphogenetic protein-2); Group B (sintered bone modified with surface mineralization) and Group C (sintered bone only). The three groups were observed by scanning electron microscopy (SEM) before the experiments, respectively. Then MC3T3-E1 cells were cultured on the surfaces of the three kinds of material, respectively. The cell adhesion rate was assessed by precipitation method. The proliferative ability of MC3T3-E1 cells were measured with MTT assay. And the ALP staining and measurement of alkaline phosphatase (ALP) activity were performed to assess the differentiation of cells into osteoblasts. The SEM results showed that the materials in the three groups retained the natural pore structure and the pore sizes were in the range between 200-850 μm. The adhesive ratio measurements and MTT assay suggested that adhesion and proliferation of MC3T3-E1 cells in Group A were much higher than those in Group B and Group C (P < 0.05). The ALP staining and ALP activity of MC3T3-E1 cells in Group A were significantly higher than those in Group B and Group C (P < 0.05). The sintered bone modified with surface mineralization/P24 composite material was confirmed to improve the adhesion rate and proliferation and osteodifferentiation of MC3T3-E1 cells, and maintained their morphology.

Abrogation of Cbl-PI3K interaction increases bone formation and osteoblast proliferation.

PubMed

Brennan, Tracy; Adapala, Naga Suresh; Barbe, Mary F; Yingling, Vanessa; Sanjay, Archana

2011-11-01

Cbl is an adaptor protein and E3 ligase that plays both positive and negative roles in several signaling pathways that affect various cellular functions. Tyrosine 737 is unique to Cbl and phosphorylated by Src family kinases. Phosphorylated CblY737 creates a binding site for the p85 regulatory subunit of phosphatidylinositol 3 kinase (PI3K) that also plays an important role in the regulation of bone homeostasis. To investigate the role of Cbl-PI3K interaction in bone homeostasis, we examined knock-in mice in which the PI3K binding site on Cbl was ablated due to the substitution of tyrosine 737 to phenylalanine (Cbl(YF/YF), YF mice). We previously reported that bone volume in these mice is increased due to decreased osteoclast function (Adapala et al., J Biol Chem 285:36745-36758, 19). Here, we report that YF mice also have increased bone formation and osteoblast numbers. In ex vivo cultures bone marrow-derived YF osteoblasts showed increased Col1A expression and their proliferation was also significantly augmented. Moreover, proliferation of MC3T3-E1 cells was increased after treatment with conditioned medium generated by culturing YF bone marrow stromal cells. Expression of stromal derived factor-1 (SDF-1) was increased in YF bone marrow stromal cells compared to wild type. Increased immunostaining of SDF-1 and CXCR4 was observed in YF bone marrow stromal cells compared to wild type. Treatment of YF condition medium with neutralizing anti-SDF-1 and anti-CXCR4 antibodies attenuated MC3T3-E1 cell proliferation. Cumulatively, these results show that abrogation of Cbl-PI3K interaction perturbs bone homeostasis, affecting both osteoclast function and osteoblast proliferation.

Mechanotransduction and the functional response of bone to mechanical strain

NASA Technical Reports Server (NTRS)

Duncan, R. L.; Turner, C. H.

1995-01-01

Mechanotransduction plays a crucial role in the physiology of many tissues including bone. Mechanical loading can inhibit bone resorption and increase bone formation in vivo. In bone, the process of mechanotransduction can be divided into four distinct steps: (1) mechanocoupling, (2) biochemical coupling, (3) transmission of signal, and (4) effector cell response. In mechanocoupling, mechanical loads in vivo cause deformations in bone that stretch bone cells within and lining the bone matrix and create fluid movement within the canaliculae of bone. Dynamic loading, which is associated with extracellular fluid flow and the creation of streaming potentials within bone, is most effective for stimulating new bone formation in vivo. Bone cells in vitro are stimulated to produce second messengers when exposed to fluid flow or mechanical stretch. In biochemical coupling, the possible mechanisms for the coupling of cell-level mechanical signals into intracellular biochemical signals include force transduction through the integrin-cytoskeleton-nuclear matrix structure, stretch-activated cation channels within the cell membrane, G protein-dependent pathways, and linkage between the cytoskeleton and the phospholipase C or phospholipase A pathways. The tight interaction of each of these pathways would suggest that the entire cell is a mechanosensor and there are many different pathways available for the transduction of a mechanical signal. In the transmission of signal, osteoblasts, osteocytes, and bone lining cells may act as sensors of mechanical signals and may communicate the signal through cell processes connected by gap junctions. These cells also produce paracrine factors that may signal osteoprogenitors to differentiate into osteoblasts and attach to the bone surface. Insulin-like growth factors and prostaglandins are possible candidates for intermediaries in signal transduction. In the effector cell response, the effects of mechanical loading are dependent upon the magnitude, duration, and rate of the applied load. Longer duration, lower amplitude loading has the same effect on bone formation as loads with short duration and high amplitude. Loading must be cyclic to stimulate new bone formation. Aging greatly reduces the osteogenic effects of mechanical loading in vivo. Also, some hormones may interact with local mechanical signals to change the sensitivity of the sensor or effector cells to mechanical load.

Hydrogels That Allow and Facilitate Bone Repair, Remodeling, and Regeneration

PubMed Central

Short, Aaron R.; Koralla, Deepthi; Deshmukh, Ameya; Wissel, Benjamin; Stocker, Benjamin; Calhoun, Mark; Dean, David; Winter, Jessica O.

2015-01-01

Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current “gold standard” treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects. PMID:26693013

Hydrogels That Allow and Facilitate Bone Repair, Remodeling, and Regeneration.

PubMed

Short, Aaron R; Koralla, Deepthi; Deshmukh, Ameya; Wissel, Benjamin; Stocker, Benjamin; Calhoun, Mark; Dean, David; Winter, Jessica O

2015-10-28

Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current "gold standard" treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects.

Bioactive nano-fibrous scaffold for vascularized craniofacial bone regeneration.

PubMed

Prabha, Rahul Damodaran; Kraft, David Christian Evar; Harkness, Linda; Melsen, Birte; Varma, Harikrishna; Nair, Prabha D; Kjems, Jorgen; Kassem, Moustapha

2018-03-01

There has been a growing demand for bone grafts for correction of bone defects in complicated fractures or tumours in the craniofacial region. Soft flexible membrane like material that could be inserted into defect by less invasive approaches; promote osteoconductivity and act as a barrier to soft tissue in growth while promoting bone formation is an attractive option for this region. Electrospinning has recently emerged as one of the most promising techniques for fabrication of extracellular matrix such as nano-fibrous scaffolds that can serve as a template for bone formation. To overcome the limitation of cell penetration of electrospun scaffolds and improve on its osteoconductive nature, in this study, we fabricated a novel electrospun composite scaffold of polyvinyl alcohol (PVA)-poly (ε) caprolactone (PCL)-Hydroxyapatite based bioceramic (HAB), namely, PVA-PCL-HAB. The scaffold prepared by dual electrospinning of PVA and PCL with HAB overcomes reduced cell attachment associated with hydrophobic PCL by combination with a hydrophilic PVA and the HAB can contribute to enhance osteoconductivity. We characterized the physicochemical and biocompatibility properties of the new scaffold material. Our results indicate PVA-PCL-HAB scaffolds support attachment and growth of stromal stem cells; [human bone marrow skeletal (mesenchymal) stem cells and dental pulp stem cells]. In addition, the scaffold supported in vitro osteogenic differentiation and in vivo vascularized bone formation. Thus, PVA-PCL-HAB scaffold is a suitable potential material for therapeutic bone regeneration in dentistry and orthopaedics. Copyright © 2017 John Wiley & Sons, Ltd.

Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells

PubMed Central

Florencio-Silva, Rinaldo; Sasso-Cerri, Estela; Simões, Manuel Jesus; Cerri, Paulo Sérgio

2015-01-01

Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling. PMID:26247020

Chromatin immunoprecipitation assays: application of ChIP-on-chip for defining dynamic transcriptional mechanisms in bone cells.

PubMed

van der Deen, Margaretha; Hassan, Mohammad Q; Pratap, Jitesh; Teplyuk, Nadiya M; Young, Daniel W; Javed, Amjad; Zaidi, Sayyed K; Lian, Jane B; Montecino, Martin; Stein, Janet L; Stein, Gary S; van Wijnen, Andre J

2008-01-01

Normal cell growth and differentiation of bone cells requires the sequential expression of cell type specific genes to permit lineage specification and development of cellular phenotypes. Transcriptional activation and repression of distinct sets of genes support the anabolic functions of osteoblasts and the catabolic properties of osteoclasts. Furthermore, metastasis of tumors to the bone environment is controlled by transcriptional mechanisms. Insights into the transcriptional regulation of genes in bone cells may provide a conceptual basis for improved therapeutic approaches to treat bone fractures, genetic osteopathologies, and/or cancer metastases to bone. Chromatin immunoprecipitation (ChIP) is a powerful technique to establish in vivo binding of transcription factors to the promoters of genes that are either activated or repressed in bone cells. Combining ChIP with genomic microarray analysis, colloquially referred to as "ChIP-on-chip," has become a valuable method for analysis of endogenous protein/DNA interactions. This technique permits assessment of chromosomal binding sites for transcription factors or the location of histone modifications at a genomic scale. This chapter discusses protocols for performing chromatin immunoprecipitation experiments, with a focus on ChIP-on-chip analysis. The information presented is based on the authors' experience with defining interactions of Runt-related (RUNX) transcription factors with bone-related genes within the context of the native nucleosomal organization of intact osteoblastic cells.

Gap Junction Intercellular Communication: A Review of a Potential Platform to Modulate Craniofacial Tissue Engineering

PubMed Central

Rossello, Ricardo A.; Kohn, David H.

2009-01-01

Defects in craniofacial tissues, resulting from trauma, congenital abnormalities, oncologic resection or progressive deforming diseases, may result in aesthetic deformity, pain and reduced function. Restoring the structure, function and aesthetics of craniofacial tissues represents a substantial clinical problem in need of new solutions. More biologically-interactive biomaterials could potentially improve the treatment of craniofacial defects, and an understanding of developmental processes may help identify strategies and materials that can be used in tissue engineering. One such strategy that can potentially advance tissue engineering is cell–cell communication. Gap junction intercellular communication is the most direct way of achieving such signaling. Gap junction communication through connexin-mediated junctions, in particular connexin 43 (Cx43), plays a major role bone development. Given the important role of Cx43 in controlling development and differentiation, especially in bone cells, controlling the expression of Cx43 may provide control over cell-to-cell communication and may help overcome some of the challenges in craniofacial tissue engineering. Following a review of gap junctions in bone cells, the ability to enhance cell–cell communication and osteogenic differentiation via control of gap junctions is discussed, as is the potential utility of this approach in craniofacial tissue engineering. PMID:18481782

Bone as a source of organism vitality and regeneration.

PubMed

Mackiewicz, Zygmunt; Niklińska, Wiesława Ewa; Kowalewska, Jolanta; Chyczewski, Lech

2011-01-01

The most important features that determine the vital role of bone include: a) a continuous supply of calcium, which is indispensible for every cell of the entire organism at all times, and b) the delivery of circulating blood cells and some adult stem cells to keep the body vigorous, ready for self-reparation, and continuously rebuilding throughout life. These functions of bones are no less important than protecting the body cavities, serving as mechanical levers connected to the muscles, and determining the shape and dimensions of the entire organism. The aim of this review was to address some basic cellular and molecular knowledge to better understand the complex interactions of bone structural components. The apprehension of osteoblast differentiation and its local regulation has substantially increased in recent years. It has been suggested that osteocytes, cells within the bone matrix, act as regulatory mechanosensors. Therefore immobility as well as limited activity has a dramatic effect on bone structure and influences a broad spectrum of bone physiology-related functions as well as the functions of many other organs. Lifelong bone rebuilding is modulated through several pathways, including the Wnt pathway that regulates bone formation and resorption. In the adult skeleton, bone is continuously renewed in response to a variety of stimuli, such as the specific process of remodeling dependent on RANK/ /RANKL/OPG interactions. Better understanding of bone biology provides opportunities for the development of more effective prevention and treatment modalities for a variety of bone diseases, including new approaches to adult stem cell-based therapies.

Role of Cbl-PI3K Interaction during Skeletal Remodeling in a Murine Model of Bone Repair.

PubMed

Scanlon, Vanessa; Soung, Do Yu; Adapala, Naga Suresh; Morgan, Elise; Hansen, Marc F; Drissi, Hicham; Sanjay, Archana

2015-01-01

Mice in which Cbl is unable to bind PI3K (YF mice) display increased bone volume due to enhanced bone formation and repressed bone resorption during normal bone homeostasis. We investigated the effects of disrupted Cbl-PI3K interaction on fracture healing to determine whether this interaction has an effect on bone repair. Mid-diaphyseal femoral fractures induced in wild type (WT) and YF mice were temporally evaluated via micro-computed tomography scans, biomechanical testing, histological and histomorphometric analyses. Imaging analyses revealed no change in soft callus formation, increased bony callus formation, and delayed callus remodeling in YF mice compared to WT mice. Histomorphometric analyses showed significantly increased osteoblast surface per bone surface and osteoclast numbers in the calluses of YF fractured mice, as well as increased incorporation of dynamic bone labels. Furthermore, using laser capture micro-dissection of the fracture callus we found that cells lacking Cbl-PI3K interaction have higher expression of Osterix, TRAP, and Cathepsin K. We also found increased expression of genes involved in propagating PI3K signaling in cells isolated from the YF fracture callus, suggesting that the lack of Cbl-PI3K interaction perhaps results in enhanced PI3K signaling, leading to increased bone formation, but delayed remodeling in the healing femora.

The interactions of the cells in the development of osteoporotic changes in bones under space flight conditions

NASA Astrophysics Data System (ADS)

Rodionova, Natalia; Kabitskaya, Olga

2016-07-01

Using the methods of electron microscopy and autoradiography with ³N-glycine and ³N-thymidine on biosatellites "Bion-11" (Macaca mulatta, the duration of the experiments -10 days), "Bion-M1" (mouse C57 Black, duration of the flight - 30 days) in the experiments with modeled hypokinesia (white rats, hind limbs unloading, the duration of the experiments 28 days) new data about the morpho-functional peculiarities of cellular interactions in adaptive remodeling zones of bone structures under normal conditions and after exposure of animals to microgravity. Our conception on remodeling proposes the following sequence in the development of cellular interactions after decrease of the mechanical loading: a primary response of osteocytes (mechanosensory cells) to the mechanical stimulus; osteocytic remodeling (osteolysis); transmission of the mechanical signals through a system of canals and processes to functionally active osteoblasts and paving endost one as well as to the bone-marrow stromal cells and perivascular cells. As a response to the mechanical stimulus (microgravity) the system of perivascular cell-stromal cell-preosteoblast-osteoblast shows a delay in proliferation, differentiation and specific functioning of the osteogenetic cells, the number of apoptotic osteoblasts increases. Then the osteoclastic reaction occurs (attraction of monocytes and formation of osteoclasts, bone matrix resorption in the loci of apoptosis of osteoblasts and osteocytes). The macrophagal reaction is followed by osteoblastogenesis, which appears to be a rehabilitating process. However, during prolonged absence of mechanical stimuli (microgravity, long-time immobilization) the adaptive activization of osteoblastogenesis doesn't occur (as it is the case during the physiological remodeling of bone tissue) or it occurs to a smaller degree. The loading deficit leads to an adaptive differentiation of stromal cells to fibroblastic cells and adipocytes in remodeling loci. These cell reactions are considered as adaptive-compensatory, but they don't result in rehabilitation of the resorbed bone tissue. This sequence of cells interactions is considered as a mechanism of bone tissue loss which underlies the development of osteopenia and osteoporosis under the mechanical loading deficit.

3D conductive nanocomposite scaffold for bone tissue engineering

PubMed Central

Shahini, Aref; Yazdimamaghani, Mostafa; Walker, Kenneth J; Eastman, Margaret A; Hatami-Marbini, Hamed; Smith, Brenda J; Ricci, John L; Madihally, Sundar V; Vashaee, Daryoosh; Tayebi, Lobat

2014-01-01

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli. PMID:24399874

3D conductive nanocomposite scaffold for bone tissue engineering.

PubMed

Shahini, Aref; Yazdimamaghani, Mostafa; Walker, Kenneth J; Eastman, Margaret A; Hatami-Marbini, Hamed; Smith, Brenda J; Ricci, John L; Madihally, Sundar V; Vashaee, Daryoosh; Tayebi, Lobat

2014-01-01

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli.

Osteoblast-secreted WISP-1 promotes adherence of prostate cancer cells to bone via the VCAM-1/integrin α4β1 system.

PubMed

Chang, An-Chen; Chen, Po-Chun; Lin, Yu-Feng; Su, Chen-Ming; Liu, Ju-Fang; Lin, Tien-Huang; Chuang, Show-Mei; Tang, Chih-Hsin

2018-07-10

Bone metastasis is a frequent occurrence in prostate cancer (PCa) that is associated with severe complications such as fracture, bone pain and hypercalcemia. The cross-talk between metastatic cancer cells and bone is critical to the development and progression of bone metastases. In our previous data, we have described how the involvement of the Wnt-induced secreted protein-1/vascular cell adhesion molecule-1 (WISP-1/VCAM-1) system in this tumor-bone interaction contributes to human PCa cell motility. In this study, we found that WISP-1 regulates bone mineralization by inducing bone morphogenetic protein-2 (BMP2), BMP4 and osteopontin (OPN) expression in osteoblasts. We also found that WISP-1 inhibited RANKL-dependent osteoclastogenesis. Moreover, osteoblast-derived WISP-1 enhanced VCAM-1 expression in PCa cells and subsequently promoted the adherence of cancer cells to osteoblasts. Furthermore, endothelin-1 (ET-1) expression in PCa cells was regulated by osteoblast-derived WISP-1, which promoted integrin α4β1 expression in osteoblasts via the MAPK pathway. Pretreatment of PCa cells with VCAM-1 antibody or osteoblasts with integrin α4β1 antibody attenuated the adherence of PCa cells to osteoblasts, suggesting that integrin α4β1 serves as a ligand that captures VCAM-1 + metastatic tumor cells adhering to osteoblasts. Our findings reveal that osteoblast-derived WISP-1 plays a key role in regulating the adhesion of PCa cells to osteoblasts via the VCAM-1/integrin α4β1 system. Osteoblast-derived WISP-1 is a promising target for the prevention and inhibition of PCa-bone interaction. Copyright © 2018 Elsevier B.V. All rights reserved.

Bone modeling and cell-material interface responses induced by nickel-titanium shape memory alloy after periosteal implantation.

PubMed

Ryhänen, J; Kallioinen, M; Tuukkanen, J; Lehenkari, P; Junila, J; Niemelä, E; Sandvik, P; Serlo, W

1999-07-01

The purpose of this study was to evaluate the new bone formation, modeling and cell-material interface responses induced by nickel-titanium shape memory alloy after periosteal implantation. We used a regional acceleratory phenomenon (RAP) model, in which a periosteal contact stimulus provokes an adaptive modelling response. NiTi has thermal shape memory and superelasticity properties uncommon in other implant alloys. So far, there are insufficient data concerning the biocompatibility of NiTi as a bone implant. NiTi was compared to stainless steel (stst) and Ti-6Al-4V. The test implant was placed in contact with the intact femur periosteum, but it was not fixed inside the bone. Histomorphometry with digital image analysis was used to determine the bone formation and resorption parameters. The ultrastructural features of cell-material adhesion were analysed with scanning electron microscopy (FESEM). A typical peri-implant bone wall modelation was seen due to the normal RAP. The maximum new woven bone formation started earlier (2 weeks) in the Ti-6Al-4V group than in the NiTi (P < 0.01) group, but also decreased earlier, and at 8 weeks the NiTi (P < 0.05) and stst (P < 0.005) groups had greater cortical bone width. At 12 and 26 weeks no statistical differences were seen in the histomorphometric values. The histological response of the soft tissues around the NiTi implant was also clearly non-toxic and non-irritating. Cell adhesion and focal contacts were similar between the materials studied by FESEM. We conclude that NiTi had no negative effect on total new bone formation or normal RAP after periosteal implantation during a 26-week follow-up.

Interactions between MSCs and Immune Cells: Implications for Bone Healing

PubMed Central

Kovach, Tracy K.; Dighe, Abhijit S.; Lobo, Peter I.; Cui, Quanjun

2015-01-01

It is estimated that, of the 7.9 million fractures sustained in the United States each year, 5% to 20% result in delayed or impaired healing requiring therapeutic intervention. Following fracture injury, there is an initial inflammatory response that plays a crucial role in bone healing; however, prolonged inflammation is inhibitory for fracture repair. The precise spatial and temporal impact of immune cells and their cytokines on fracture healing remains obscure. Some cytokines are reported to be proosteogenic while others inhibit bone healing. Cell-based therapy utilizing mesenchymal stromal cells (MSCs) is an attractive option for augmenting the fracture repair process. Osteoprogenitor MSCs not only differentiate into bone, but they also exert modulatory effects on immune cells via a variety of mechanisms. In this paper, we review the current literature on both in vitro and in vivo studies on the role of the immune system in fracture repair, the use of MSCs in the enhancement of fracture healing, and interactions between MSCs and immune cells. Insight into this paradigm can provide valuable clues in identifying cellular and noncellular targets that can potentially be modulated to enhance both natural bone healing and bone repair augmented by the exogenous addition of MSCs. PMID:26000315

Obesity-driven disruption of haematopoiesis and the bone marrow niche.

PubMed

Adler, Benjamin J; Kaushansky, Kenneth; Rubin, Clinton T

2014-12-01

Obesity markedly increases susceptibility to a range of diseases and simultaneously undermines the viability and fate selection of haematopoietic stem cells (HSCs), and thus the kinetics of leukocyte production that is critical to innate and adaptive immunity. Considering that blood cell production and the differentiation of HSCs and their progeny is orchestrated, in part, by complex interacting signals emanating from the bone marrow microenvironment, it is not surprising that conditions that disturb bone marrow structure inevitably disrupt both the numbers and lineage-fates of these key blood cell progenitors. In addition to the increased adipose burden in visceral and subcutaneous compartments, obesity causes a marked increase in the size and number of adipocytes encroaching into the bone marrow space, almost certainly disturbing HSC interactions with neighbouring cells, which include osteoblasts, osteoclasts, mesenchymal cells and endothelial cells. As the global obesity pandemic grows, the short-term and long-term consequences of increased bone marrow adiposity on HSC lineage selection and immune function remain uncertain. This Review discusses the differentiation and function of haematopoietic cell populations, the principal physicochemical components of the bone marrow niche, and how this environment influences HSCs and haematopoiesis in general. The effect of adipocytes and adiposity on HSC and progenitor cell populations is also discussed, with the goal of understanding how obesity might compromise the core haematopoietic system.

Inorganic materials for bone repair or replacement applications.

PubMed

Hertz, Audrey; Bruce, Ian J

2007-12-01

In recent years, excipient systems have been used increasingly in biomedicine in reconstructive and replacement surgery, as bone cements, drug-delivery vehicles and contrast agents. Particularly, interest has been growing in the development and application of controlled pore inorganic ceramic materials for use in bone-replacement and bone-repair roles and, in this context, attention has been focused on calcium-phosphate, bioactive glasses and SiO2- and TiO2-based materials. It has been shown that inorganic materials that most closely mimic bone structure and surface chemistry most closely function best in bone replacement/repair and, in particular, if a substance possesses a macroporous structure (pores and interconnections >100 microm diameter), then cell infiltration, bone growth and vascularization can all be promoted. The surface roughness and micro/mesoporosity of a material have also been observed to significantly influence its ability to promote apatite nucleation and cell attachment significantly. Pores (where present) can also be packed with pharmaceuticals and biomolecules (e.g., bone morphogenetic proteins [BMPs], which can stimulate bone formation). Finally, the most bio-efficient - in terms of collagen formation and apatite nucleation - materials are those that are able to provide soluble mineralizing species (Si, Ca, PO(4)) at their implant sites and/or are doped or have been surface-activated with specific functional groups. This article presents the context and latest advances in the field of bone-repair materials, especially with respect to the development of bioactive glasses and micro/mesoporous and macroporous inorganic scaffolds. It deals with the possible methods of preparing porous pure/doped or functionalized silicas or their composites, the studies that have been undertaken to evaluate their abilities to act as bone repair scaffolds and also presents future directions for work in that context.

Recent progress in injectable bone repair materials research

NASA Astrophysics Data System (ADS)

Chen, Zonggang; Zhang, Xiuli; Kang, Lingzhi; Xu, Fei; Wang, Zhaoling; Cui, Fu-Zhai; Guo, Zhongwu

2015-12-01

Minimally invasive injectable self-setting materials are useful for bone repairs and for bone tissue regeneration in situ. Due to the potential advantages of these materials, such as causing minimal tissue injury, nearly no influence on blood supply, easy operation and negligible postoperative pain, they have shown great promises and successes in clinical applications. It has been proposed that an ideal injectable bone repair material should have features similar to that of natural bones, in terms of both the microstructure and the composition, so that it not only provides adequate stimulus to facilitate cell adhesion, proliferation and differentiation but also offers a satisfactory biological environment for new bone to grow at the implantation site. This article reviews the properties and applications of injectable bone repair materials, including those that are based on natural and synthetic polymers, calcium phosphate, calcium phosphate/polymer composites and calcium sulfate, to orthopedics and bone tissue repairs, as well as the progress made in biomimetic fabrication of injectable bone repair materials.

Insights into material and structural basis of bone fragility from diseases associated with fractures: how determinants of the biomechanical properties of bone are compromised by disease.

PubMed

Chavassieux, P; Seeman, E; Delmas, P D

2007-04-01

Minimal trauma fractures in bone diseases are the result of bone fragility. Rather than considering bone fragility as being the result of a reduced amount of bone, we recognize that bone fragility is the result of changes in the material and structural properties of bone. A better understanding of the contribution of each component of the material composition and structure and how these interact to maintain whole bone strength is obtained by the study of metabolic bone diseases. Disorders of collagen (osteogenesis imperfecta and Paget's disease of bone), mineral content, composition and distribution (fluorosis and osteomalacia); diseases of high remodeling (postmenopausal osteoporosis, hyperparathyroidism, and hyperthyroidism) and low remodeling (osteopetrosis, pycnodysostosis); and other diseases (idiopathic male osteoporosis, corticosteroid-induced osteoporosis) produce abnormalities in the material composition and structure that lead to bone fragility. Observations in patients and in animal models provide insights on the biomechanical consequences of these illnesses and the nature of the qualities of bone that determine its strength.

UV-killed Staphylococcus aureus enhances adhesion and differentiation of osteoblasts on bone-associated biomaterials.

PubMed

Somayaji, Shankari N; Huet, Yvette M; Gruber, Helen E; Hudson, Michael C

2010-11-01

Titanium alloys (Ti) are the preferred material for orthopedic applications. However, very often, these metallic implants loosen over a long period and mandate revision surgery. For implant success, osteoblasts must adhere to the implant surface and deposit a mineralized extracellular matrix (ECM). Here, we utilized UV-killed Staphylococcus aureus as a novel osteoconductive coating for Ti surfaces. S. aureus expresses surface adhesins capable of binding to bone and biomaterials directly. Furthermore, interaction of S. aureus with osteoblasts activates growth factor-related pathways that potentiate osteogenesis. Although UV-killed S. aureus cells retain their bone-adhesive ability, they do not stimulate significant immune modulator expression. All of the abovementioned properties were utilized for a novel implant coating so as to promote osteoblast recruitment and subsequent cell functions on the bone-implant interface. In this study, osteoblast adhesion, proliferation, and mineralized ECM synthesis were measured on Ti surfaces coated with fibronectin with and without UV-killed bacteria. Osteoblast adhesion was enhanced on Ti alloy surfaces coated with bacteria compared to uncoated surfaces, while cell proliferation was sustained comparably on both surfaces. Osteoblast markers such as collagen, osteocalcin, alkaline phosphatase activity, and mineralized nodule formation were increased on Ti alloy coated with bacteria compared to uncoated surfaces.

Bone cell communication factors and Semaphorins

PubMed Central

Negishi-Koga, Takako; Takayanagi, Hiroshi

2012-01-01

Bone tissue is continuously renewed throughout adult life by a process called 'remodeling', which involves a dynamic interplay among bone cells including osteoclasts, osteoblasts and osteocytes. For example, a tight coupling between bone resorption and formation is essential for the homeostasis of the skeletal system. Studies on the coupling mechanism in physiological and pathological settings have revealed that osteoclasts or osteoclastic bone resorption promote bone formation through the production of diverse coupling factors. The classical coupling factors are the molecules that promote bone formation after resorption, but there may be distinct mechanisms at work in various phases of bone remodeling. A recent study revealed that the Semaphorin 4D expressed by osteoclasts inhibits bone formation, which represents a mechanism by which coupling is dissociated. Furthermore, it has been demonstrated that osteoblastic expression of Semaphorin 3A exerts an osteoprotective effect by both suppressing bone resorption and increasing bone formation. Thus, recent advances have made it increasingly clear that bone remodeling is regulated by not only classical coupling factors, but also molecules that mediate cell–cell communication among bone cells. We propose that such factors be called bone cell communication factors, which control the delicate balance of the interaction of bone cells so as to maintain bone homeostasis. PMID:24171101

Independent effects of the chemical and microstructural surface properties of polymer/ceramic composites on proliferation and osteogenic differentiation of human MSCs.

PubMed

Sun, Lanying; Danoux, Charlène B; Wang, Qibao; Pereira, Daniel; Barata, David; Zhang, Jingwei; LaPointe, Vanessa; Truckenmüller, Roman; Bao, Chongyun; Xu, Xin; Habibovic, Pamela

2016-09-15

Within the general aim of finding affordable and sustainable regenerative solutions for damaged and diseased tissues and organs, significant efforts have been invested in developing synthetic alternatives to natural bone grafts, such as autografts. Calcium phosphate (CaP) ceramics are among widely used synthetic bone graft substitutes, but their mechanical properties and bone regenerative capacity are still outperformed by their natural counterparts. In order to improve the existing synthetic bone graft substitutes, it is imperative to understand the effects of their individual properties on a biological response, and to find a way to combine the desired properties into new, improved functional biomaterials. To this end, we studied the independent effects of the chemical composition and surface microstructure of a poly(lactic acid)/hydroxyapatite (PLA/HA) composite material on the proliferation and osteogenic differentiation of clinically relevant bone marrow-derived human mesenchymal stromal cells (hMSCs). While the molecular weight of the polymer and presence/absence of the ceramic phase were used as the chemical variables, a soft embossing technique was used to pattern the surfaces of all materials with either pits or pillars with identical microscale dimensions. The results indicated that, while cell morphology was affected by both the presence and availability of HA and by the surface microstructure, the effect of the latter parameter on cell proliferation was negligible. The osteogenic differentiation of hMSCs, and in particular the expression of bone morphogenetic protein 2 (BMP-2) and osteopontin (OP) were significantly enhanced when cells were cultured on the composite based on low-molecular-weight PLA, as compared to the high-molecular-weight PLA-based composite and the two pure polymers. The OP expression on the low-molecular-weight PLA-based composite was further enhanced when the surface was patterned with pits. Taken together, within this experimental set up, the individual effect of the chemistry, and in particular of the presence of CaP, was more pronounced than the individual effect of the surface microstructure, although their combined effects were, in some cases, synergistic. The approach presented here opens new routes to study the interactions of biomaterials with the biological environment in greater depths, which can serve as a starting point for developing biomaterials with improved bioactivity. The aim of the this study was to obtain insight into independent effects of the chemical composition and surface microstructure of a poly(lactic acid)/hydroxyapatite (PLA/HA) composite material on the morphology, proliferation and osteogenic differentiation of clinically relevant bone marrow-derived human mesenchymal stromal cells (hMSCs). While the need for synthetic alternatives for natural bone in bone regenerative strategies is rapidly increasing, the clinical performance of synthetic biomaterials needs to be further improved. To do this successfully, we believe that a better understanding of the relationship between a property of a material and a biological response is imperative. This study is a step forward in this direction, and we are therefore convinced that it will be of interest to the readers of Acta Biomaterialia. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Engineering the bone-ligament interface using polyethylene glycol diacrylate incorporated with hydroxyapatite.

PubMed

Paxton, Jennifer Z; Donnelly, Kenneth; Keatch, Robert P; Baar, Keith

2009-06-01

Ligaments and tendons have previously been tissue engineered. However, without the bone attachment, implantation of a tissue-engineered ligament would require it to be sutured to the remnant of the injured native tissue. Due to slow repair and remodeling, this would result in a chronically weak tissue that may never return to preinjury function. In contrast, orthopaedic autograft reconstruction of the ligament often uses a bone-to-bone technique for optimal repair. Since bone-to-bone repairs heal better than other methods, implantation of an artificial ligament should also occur from bone-to-bone. The aim of this study was to investigate the use of a poly(ethylene glycol) diacrylate (PEGDA) hydrogel incorporated with hydroxyapatite (HA) and the cell-adhesion peptide RGD (Arg-Gly-Asp) as a material for creating an in vitro tissue interface to engineer intact ligaments (i.e., bone-ligament-bone). Incorporation of HA into PEG hydrogels reduced the swelling ratio but increased mechanical strength and stiffness of the hydrogels. Further, HA addition increased the capacity for cell growth and interface formation. RGD incorporation increased the swelling ratio but decreased mechanical strength and stiffness of the material. Optimum levels of cell attachment were met using a combination of both HA and RGD, but this material had no better mechanical properties than PEG alone. Although adherence of the hydrogels containing HA was achieved, failure occurs at about 4 days with 5% HA. Increasing the proportion of HA improved interface formation; however, with high levels of HA, the PEG HA composite became brittle. This data suggests that HA, by itself or with other materials, might be well suited for engineering the ligament-bone interface.

Morphological and functional changes in RAW264 macrophage-like cells in response to a hydrated layer of carbonate-substituted hydroxyapatite.

PubMed

Igeta, Kazuki; Kuwamura, Yuta; Horiuchi, Naohiro; Nozaki, Kosuke; Shiraishi, Daichi; Aizawa, Mamoru; Hashimoto, Kazuaki; Yamashita, Kimihiro; Nagai, Akiko

2017-04-01

Synthetic hydroxyapatite (HAp) is used clinically as a material for bone prostheses owing to its good bone-bonding ability; however, it does not contribute to bone remodeling. Carbonate-substituted hydroxyapatite (CAp) has greater bioresorption capacity than HAp while having similar bone-bonding potential, and is therefore considered as a next promising material for bone prostheses. However, the effects of the CAp instability on inflammatory and immune responses are unknown in detail. Here, we show that the surface layer of CAp is more hydrated than that of HAp and induces changes in the shape and function of macrophage-like cells. HAp and CAp were synthesized by wet method and molded into disks. The carbonate content of CAp disks was 6.2% as determined by Fourier transform (FT) infrared spectral analysis. Diffuse reflectance infrared FT analysis confirmed that physisorbed water and surface hydroxyl groups (OH - ) were increased whereas structural OH - was decreased on the CAp as compared to the HAp surface. The degree of hydroxylation in CAp was comparable to that in bone-apatite structures, and the CAp surface exhibited greater hydrophilicity and solubility than HAp. We investigated immune responses to these materials by culturing RAW264 cells (macrophage precursors) on their surfaces. Cell spreading on the CAp disk was suppressed and the secretion level of inflammatory cytokines was reduced as compared to cells grown on HAp. These results indicate that the greater surface hydration of CAp surface can attenuate adverse inflammatory responses to implanted bone prostheses composed of this material. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1063-1070, 2017. © 2017 Wiley Periodicals, Inc.

Fat Layer from Medullary Canal Reamer Aspirate for Potential Use as a Supplemental Osteoinductive Bone Graft Material.

PubMed

Sinclair, Sarina S Kay; Horton, C Olsen; Jeray, Kyle J; Tanner, Stephanie L; Burgl, Karen J L

2015-01-01

Mesenchymal stem cells (MSCs) are of therapeutic interest to clinicians and researchers, as they have been shown to augment the osteogenic properties of bone grafts. MSCs are known to be prevalent in bone marrow, but are still limited in numbers. Hence, additional sources of MSCs are beneficial to increasing grafting potential. Aspirate material collected using the Reamer/Irrigator/Aspirator (RIA) device (Synthes; Paoli, PA) during reaming of the femoral shaft consists of three main components: bone fragments, liquid flow-through, and a fat layer. Currently, only the bone and liquid layers have been examined for osteoinductive elements, and the bone fragments are exclusively used as autologous bone graft. In the present study, a method to promote cellular outgrowth, tapping proliferative capacity from the previously discarded fatty layer of RIA aspirate, is described. Proliferating cells were successfully isolated from the bone and fatty layers of a consenting patient and found to be viable after liquid nitrogen storage. The osteogenic differentiation potential of the cells isolated from the fat and bone layers was assessed. Cells from both layers of the aspirate expressed statistically significant levels (p < 0.05) of the bone cell marker alkaline phosphatase compared to the control cells, suggesting differentiation along the osteoblastic pathway. Results from this pilot study indicate that the traditionally discarded fatty element of RIA aspirate may be a source of MSCs with bone-forming capabilities and the described isolation technique is effective. Combining the aspirate fatty and bony elements may enhance the clinical success of the RIA autograft.

Cell studies of hybridized carbon nanofibers containing bioactive glass nanoparticles using bone mesenchymal stromal cells

NASA Astrophysics Data System (ADS)

Zhang, Xiu-Rui; Hu, Xiao-Qing; Jia, Xiao-Long; Yang, Li-Ka; Meng, Qing-Yang; Shi, Yuan-Yuan; Zhang, Zheng-Zheng; Cai, Qing; Ao, Yin-Fang; Yang, Xiao-Ping

2016-12-01

Bone regeneration required suitable scaffolding materials to support the proliferation and osteogenic differentiation of bone-related cells. In this study, a kind of hybridized nanofibrous scaffold material (CNF/BG) was prepared by incorporating bioactive glass (BG) nanoparticles into carbon nanofibers (CNF) via the combination of BG sol-gel and polyacrylonitrile (PAN) electrospinning, followed by carbonization. Three types (49 s, 68 s and 86 s) of BG nanoparticles were incorporated. To understand the mechanism of CNF/BG hybrids exerting osteogenic effects, bone marrow mesenchymal stromal cells (BMSCs) were cultured directly on these hybrids (contact culture) or cultured in transwell chambers in the presence of these materials (non-contact culture). The contributions of ion release and contact effect on cell proliferation and osteogenic differentiation were able to be correlated. It was found that the ionic dissolution products had limited effect on cell proliferation, while they were able to enhance osteogenic differentiation of BMSCs in comparison with pure CNF. Differently, the proliferation and osteogenic differentiation were both significantly promoted in the contact culture. In both cases, CNF/BG(68 s) showed the strongest ability in influencing cell behaviors due to its fastest release rate of soluble silicium-relating ions. The synergistic effect of CNF and BG would make CNF/BG hybrids promising substrates for bone repairing.

Bone regeneration: molecular and cellular interactions with calcium phosphate ceramics

PubMed Central

Barrère, Florence; van Blitterswijk, Clemens A; de Groot, Klaas

2006-01-01

Calcium phosphate bioceramics are widely used in orthopedic and dental applications and porous scaffolds made of them are serious candidates in the field of bone tissue engineering. They have superior properties for the stimulation of bone formation and bone bonding, both related to the specific interactions of their surface with the extracellular fluids and cells, ie, ionic exchanges, superficial molecular rearrangement and cellular activity. PMID:17717972

Enhanced In Vivo Bone and Blood Vessel Formation by Iron Oxide and Silica Doped 3D Printed Tricalcium Phosphate Scaffolds.

PubMed

Bose, Susmita; Banerjee, Dishary; Robertson, Samuel; Vahabzadeh, Sahar

2018-05-04

Calcium phosphate (CaP) ceramics show significant promise towards bone graft applications because of the compositional similarity to inorganic materials of bone. With 3D printing, it is possible to create ceramic implants that closely mimic the geometry of human bone and can be custom-designed for unusual injuries or anatomical sites. The objective of the study was to optimize the 3D-printing parameters for the fabrication of scaffolds, with complex geometry, made from synthesized tricalcium phosphate (TCP) powder. This study was also intended to elucidate the mechanical and biological effects of the addition of Fe +3 and Si +4 in TCP implants in a rat distal femur model for 4, 8, and 12 weeks. Doped with Fe +3 and Si +4 TCP scaffolds with 3D interconnected channels were fabricated to provide channels for micronutrients delivery and improved cell-material interactions through bioactive fixation. Addition of Fe +3 into TCP enhanced early-stage new bone formation by increasing type I collagen production. Neovascularization was observed in the Si +4 doped samples after 12 weeks. These findings emphasize that the additive manufacturing of scaffolds with complex geometry from synthesized ceramic powder with modified chemistry is feasible and may serve as a potential candidate to introduce angiogenic and osteogenic properties to CaPs, leading to accelerated bone defect healing.

Nanotechnology in bone tissue engineering.

PubMed

Walmsley, Graham G; McArdle, Adrian; Tevlin, Ruth; Momeni, Arash; Atashroo, David; Hu, Michael S; Feroze, Abdullah H; Wong, Victor W; Lorenz, Peter H; Longaker, Michael T; Wan, Derrick C

2015-07-01

Nanotechnology represents a major frontier with potential to significantly advance the field of bone tissue engineering. Current limitations in regenerative strategies include impaired cellular proliferation and differentiation, insufficient mechanical strength of scaffolds, and inadequate production of extrinsic factors necessary for efficient osteogenesis. Here we review several major areas of research in nanotechnology with potential implications in bone regeneration: 1) nanoparticle-based methods for delivery of bioactive molecules, growth factors, and genetic material, 2) nanoparticle-mediated cell labeling and targeting, and 3) nano-based scaffold construction and modification to enhance physicochemical interactions, biocompatibility, mechanical stability, and cellular attachment/survival. As these technologies continue to evolve, ultimate translation to the clinical environment may allow for improved therapeutic outcomes in patients with large bone deficits and osteodegenerative diseases. Traditionally, the reconstruction of bony defects has relied on the use of bone grafts. With advances in nanotechnology, there has been significant development of synthetic biomaterials. In this article, the authors provided a comprehensive review on current research in nanoparticle-based therapies for bone tissue engineering, which should be useful reading for clinicians as well as researchers in this field. Copyright © 2015 Elsevier Inc. All rights reserved.

Adipocyte-derived players in hematologic tumors: useful novel targets?

PubMed

Jöhrer, Karin; Ploner, Christian; Thangavadivel, Shanmugapriya; Wuggenig, Philipp; Greil, Richard

2015-01-01

Adipocytes and their products play essential roles in tumor establishment and progression. As the main cellular component of the bone marrow, adipocytes may contribute to the development of hematologic tumors. This review summarizes experimental data on adipocytes and their interaction with various cancer cells. Special focus is set on the interactions of bone marrow adipocytes and normal and transformed cells of the hematopoietic system such as myeloma and leukemia cells. Current in vitro and in vivo data are summarized and the potential of novel therapeutic targets is critically discussed. Targeting lipid metabolism of cancer cells and adipocytes in combination with standard therapeutics might open novel therapeutic avenues in these cancer entities. Adipocyte-derived products such as free fatty acids and specific adipokines such as adiponectin may be vital anti-cancer targets in hematologic malignancies. However, available data on lipid metabolism is currently mostly referring to peripheral fat cell/cancer cell interactions and results need to be evaluated specifically for the bone marrow niche.

Blood and interstitial flow in the hierarchical pore space architecture of bone tissue.

PubMed

Cowin, Stephen C; Cardoso, Luis

2015-03-18

There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blood and Interstitial flow in the hierarchical pore space architecture of bone tissue

PubMed Central

Cowin, Stephen C.; Cardoso, Luis

2015-01-01

There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells. PMID:25666410

The intestinal microbiome and skeletal fitness: connecting bugs and bones

PubMed Central

Charles, Julia F.; Ermann, Joerg; Aliprantis, Antonios O.

2015-01-01

Recent advances have dramatically increased our understanding of how organ systems interact. This has been especially true for immunology and bone biology, where the term “osteoimmunology” was coined to capture this relationship. The importance of the microbiome to the immune system has also emerged as a driver of health and disease. It makes sense therefore to ask the question: how does the intestinal microbiome influence bone biology and does dysbiosis promote bone disease? Surprisingly, few studies have analyzed this connection. A broader interpretation of this question reveals many mechanisms whereby the microbiome may affect bone cells. These include effects of the microbiome on immune cells, including myeloid progenitors and Th17 cells, as well as steroid hormones, fatty acids, serotonin and vitamin D. As mechanistic interactions of the microbiome and skeletal system are revealed within and without the immune system, novel strategies to optimize skeletal fitness may emerge. PMID:25840106

Cellular Mechanisms of Multiple Myeloma Bone Disease

PubMed Central

Oranger, Angela; Carbone, Claudia; Izzo, Maddalena; Grano, Maria

2013-01-01

Multiple myeloma (MM) is a hematologic malignancy of differentiated plasma cells that accumulates and proliferates in the bone marrow. MM patients often develop bone disease that results in severe bone pain, osteolytic lesions, and pathologic fractures. These skeletal complications have not only a negative impact on quality of life but also a possible effect in overall survival. MM osteolytic bone lesions arise from the altered bone remodeling due to both increased osteoclast activation and decreased osteoblast differentiation. A dysregulated production of numerous cytokines that can contribute to the uncoupling of bone cell activity is well documented in the bone marrow microenvironment of MM patients. These molecules are produced not only by malignant plasma cells, that directly contribute to MM bone disease, but also by bone, immune, and stromal cells interacting with each other in the bone microenvironment. This review focuses on the current knowledge of MM bone disease biology, with particular regard on the role of bone and immune cells in producing cytokines critical for malignant plasma cell proliferation as well as in osteolysis development. Therefore, the understanding of MM pathogenesis could be useful to the discovery of novel agents that will be able to both restore bone remodelling and reduce tumor burden. PMID:23818912

Direct cytotoxicity evaluation of 63S bioactive glass and bone-derived hydroxyapatite particles using yeast model and human chondrocyte cells by microcalorimetry.

PubMed

Doostmohammadi, A; Monshi, A; Fathi, M H; Karbasi, S; Braissant, O; Daniels, A U

2011-10-01

In this study, the cytotoxicity evaluation of prepared 63S bioactive glass and bone-derived hydroxyapatite particles with yeast and human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. Elemental analysis was carried out by XRF and EDXRF. Amorphous structure of the glass and completely crystalline structure of HA were detected by XRD analysis. Finally, the cytotoxicity of bioactive glass and bone-derived HA particles with yeast and cultured human chondrocyte cells was evaluated using IMNC. The results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass, and bone-derived HA particles. Also the results indicated that yeast model which is much easier to handle, can be considered as a good proxy and can provide a rapid primary estimate of the ranges to be used in assays involving human cells. All of these results confirmed that IMNC is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods.

Cell-wall recovery after irreversible deformation of wood

NASA Astrophysics Data System (ADS)

Keckes, Jozef; Burgert, Ingo; Frühmann, Klaus; Müller, Martin; Kölln, Klaas; Hamilton, Myles; Burghammer, Manfred; Roth, Stephan V.; Stanzl-Tschegg, Stefanie; Fratzl, Peter

2003-12-01

The remarkable mechanical properties of biological materials reside in their complex hierarchical architecture and in specific molecular mechanistic phenomena. The fundamental importance of molecular interactions and bond recovery has been suggested by studies on deformation and fracture of bone and nacre. Like these mineral-based materials, wood also represents a complex nanocomposite with excellent mechanical performance, despite the fact that it is mainly based on polymers. In wood, however, the mechanistic contribution of processes in the cell wall is not fully understood. Here we have combined tensile tests on individual wood cells and on wood foils with simultaneous synchrotron X-ray diffraction analysis in order to separate deformation mechanisms inside the cell wall from those mediated by cell-cell interactions. We show that tensile deformation beyond the yield point does not deteriorate the stiffness of either individual cells or foils. This indicates that there is a dominant recovery mechanism that re-forms the amorphous matrix between the cellulose microfibrils within the cell wall, maintaining its mechanical properties. This stick-slip mechanism, rather like Velcro operating at the nanometre level, provides a 'plastic response' similar to that effected by moving dislocations in metals. We suggest that the molecular recovery mechanism in the cell matrix is a universal phenomenon dominating the tensile deformation of different wood tissue types.

A fluid–structure interaction model to characterize bone cell stimulation in parallel-plate flow chamber systems

PubMed Central

Vaughan, T. J.; Haugh, M. G.; McNamara, L. M.

2013-01-01

Bone continuously adapts its internal structure to accommodate the functional demands of its mechanical environment and strain-induced flow of interstitial fluid is believed to be the primary mediator of mechanical stimuli to bone cells in vivo. In vitro investigations have shown that bone cells produce important biochemical signals in response to fluid flow applied using parallel-plate flow chamber (PPFC) systems. However, the exact mechanical stimulus experienced by the cells within these systems remains unclear. To fully understand this behaviour represents a most challenging multi-physics problem involving the interaction between deformable cellular structures and adjacent fluid flows. In this study, we use a fluid–structure interaction computational approach to investigate the nature of the mechanical stimulus being applied to a single osteoblast cell under fluid flow within a PPFC system. The analysis decouples the contribution of pressure and shear stress on cellular deformation and for the first time highlights that cell strain under flow is dominated by the pressure in the PPFC system rather than the applied shear stress. Furthermore, it was found that strains imparted on the cell membrane were relatively low whereas significant strain amplification occurred at the cell–substrate interface. These results suggest that strain transfer through focal attachments at the base of the cell are the primary mediators of mechanical signals to the cell under flow in a PPFC system. Such information is vital in order to correctly interpret biological responses of bone cells under in vitro stimulation and elucidate the mechanisms associated with mechanotransduction in vivo. PMID:23365189

A Cellular Automata Model of Bone Formation

PubMed Central

Van Scoy, Gabrielle K.; George, Estee L.; Asantewaa, Flora Opoku; Kerns, Lucy; Saunders, Marnie M.; Prieto-Langarica, Alicia

2017-01-01

Bone remodeling is an elegantly orchestrated process by which osteocytes, osteoblasts and osteoclasts function as a syncytium to maintain or modify bone. On the microscopic level, bone consists of cells that create, destroy and monitor the bone matrix. These cells interact in a coordinated manner to maintain a tightly regulated homeostasis. It is this regulation that is responsible for the observed increase in bone gain in the dominant arm of a tennis player and the observed increase in bone loss associated with spaceflight and osteoporosis. The manner in which these cells interact to bring about a change in bone quality and quantity has yet to be fully elucidated. But efforts to understand the multicellular complexity can ultimately lead to eradication of metabolic bone diseases such as osteoporosis and improved implant longevity. Experimentally validated mathematical models that simulate functional activity and offer eventual predictive capabilities offer tremendous potential in understanding multicellular bone remodeling. Here we undertake the initial challenge to develop a mathematical model of bone formation validated with in vitro data obtained from osteoblastic bone cells induced to mineralize and quantified at 26 days of culture. A cellular automata model was constructed to simulate the in vitro characterization. Permutation tests were performed to compare the distribution of the mineralization in the cultures and the distribution of the mineralization in the mathematical models. The results of the permutation test show the distribution of mineralization from the characterization and mathematical model come from the same probability distribution, therefore validating the cellular automata model. PMID:28189632

Impaired endothelial progenitor cell mobilization and dysfunctional bone marrow stroma in diabetes mellitus.

PubMed

Westerweel, Peter E; Teraa, Martin; Rafii, Shahin; Jaspers, Janneke E; White, Ian A; Hooper, Andrea T; Doevendans, Pieter A; Verhaar, Marianne C

2013-01-01

Circulating Endothelial Progenitor Cell (EPC) levels are reduced in diabetes mellitus. This may be a consequence of impaired mobilization of EPC from the bone marrow. We hypothesized that under diabetic conditions, mobilization of EPC from the bone marrow to the circulation is impaired -at least partly- due to dysfunction of the bone marrow stromal compartment. Diabetes was induced in mice by streptozotocin injection. Circulating Sca-1(+)Flk-1(+) EPC were characterized and quantified by flow cytometry at baseline and after mobilization with G-CSF/SCF injections. In vivo hemangiogenic recovery was tested by 5-FU challenge. Interaction within the bone marrow environment between CD34(+) hematopoietic progenitor cells (HPC) and supporting stroma was assessed by co-cultures. To study progenitor cell-endothelial cell interaction under normoglycemic and hyperglycemic conditions, a co-culture model using E4Orf1-transfected human endothelial cells was employed. In diabetic mice, bone marrow EPC levels were unaffected. However, circulating EPC levels in blood were lower at baseline and mobilization was attenuated. Diabetic mice failed to recover and repopulate from 5-FU injection. In vitro, primary cultured bone marrow stroma from diabetic mice was impaired in its capacity to support human CFU-forming HPC. Finally, hyperglycemia hampered the HPC supportive function of endothelial cells in vitro. EPC mobilization is impaired under experimental diabetic conditions and our data suggest that diabetes induces alterations in the progenitor cell supportive capacity of the bone marrow stroma, which could be partially responsible for the attenuated EPC mobilization and reduced EPC levels observed in diabetic patients.

Human Urine Derived Stem Cells in Combination with β-TCP Can Be Applied for Bone Regeneration.

PubMed

Guan, Junjie; Zhang, Jieyuan; Li, Haiyan; Zhu, Zhenzhong; Guo, Shangchun; Niu, Xin; Wang, Yang; Zhang, Changqing

2015-01-01

Bone tissue engineering requires highly proliferative stem cells that are easy to isolate. Human urine stem cells (USCs) are abundant and can be easily harvested without using an invasive procedure. In addition, in our previous studies, USCs have been proved to be able to differentiate into osteoblasts, chondrocytes, and adipocytes. Therefore, USCs may have great potential and advantages to be applied as a cell source for tissue engineering. However, there are no published studies that describe the interactions between USCs and biomaterials and applications of USCs for bone tissue engineering. Therefore, the objective of the present study was to evaluate the interactions between USCs with a typical bone tissue engineering scaffold, beta-Tricalcium Phosphate (β-TCP), and to determine whether the USCs seeded onto β-TCP scaffold can promote bone regeneration in a segmental femoral defect of rats. Primary USCs were isolated from urine and seeded on β-TCP scaffolds. Results showed that USCs remained viable and proliferated within β-TCP. The osteogenic differentiation of USCs within the scaffolds was demonstrated by increased alkaline phosphatase activity and calcium content. Furthermore, β-TCP with adherent USCs (USCs/β-TCP) were implanted in a 6-mm critical size femoral defect of rats for 12 weeks. Bone regeneration was determined using X-ray, micro-CT, and histologic analyses. Results further demonstrated that USCs in the scaffolds could enhance new bone formation, which spanned bone defects in 5 out of 11 rats while β-TCP scaffold alone induced modest bone formation. The current study indicated that the USCs can be used as a cell source for bone tissue engineering as they are compatible with bone tissue engineering scaffolds and can stimulate the regeneration of bone in a critical size bone defect.

Surface Mechanoengineering of a Zr-based Bulk Metallic Glass via Ar-Nanobubble Doping to Probe Cell Sensitivity to Rigid Materials

DOE PAGES

Huang, Lu; Tian, Mengkun; Wu, Dong; ...

2017-11-24

In this paper, a new materials platform, utilizing the amorphous microstructure of bulk metallic glasses (BMGs) and the versatility of ion implantation, was developed for the fundamental investigation of cell responses to substrate-rigidity variations in the gigapascal modulus range, which was previously unattainable with polymeric materials. The surface rigidity of a Zr-Al- Ni-Cu-Y BMG was modulated with low-energy Ar-ion implantation owing to the impartment of Ar nanobubbles into the amorphous matrix. Surface softening was achieved due to the formation of nanobubble-doped transitional zones in the Zrbased BMG substrate. Bone-forming cell studies on this newly designed platform demonstrated that mechanical cues,more » accompanied with the potential effects of other surface properties (i.e. roughness, morphology, and chemistry), contributed to modulating cell behaviors. Cell adhesion and actin filaments were found to be less established on less stiff surfaces, especially on the surface with an elastic modulus of 51 GPa. Cell growth appeared to be affected by surface mechanical properties. A lower stiffness was generally related to a higher growth rate. Findings in this study broadened our fundamental understanding concerning the mechanosensing of bone cells on stiff substrates. It also suggests that surface mechano-engineering of metallic materials could be a potential strategy to promote osseointegration of such materials for bone-implant applications. Further investigations are proposed to fine tune the ion implantation variables in order to further distinguish the surface-mechanical effect on bone-forming cell activities from the contributions of other surface properties.« less

Surface Mechanoengineering of a Zr-based Bulk Metallic Glass via Ar-Nanobubble Doping to Probe Cell Sensitivity to Rigid Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Lu; Tian, Mengkun; Wu, Dong

In this paper, a new materials platform, utilizing the amorphous microstructure of bulk metallic glasses (BMGs) and the versatility of ion implantation, was developed for the fundamental investigation of cell responses to substrate-rigidity variations in the gigapascal modulus range, which was previously unattainable with polymeric materials. The surface rigidity of a Zr-Al- Ni-Cu-Y BMG was modulated with low-energy Ar-ion implantation owing to the impartment of Ar nanobubbles into the amorphous matrix. Surface softening was achieved due to the formation of nanobubble-doped transitional zones in the Zrbased BMG substrate. Bone-forming cell studies on this newly designed platform demonstrated that mechanical cues,more » accompanied with the potential effects of other surface properties (i.e. roughness, morphology, and chemistry), contributed to modulating cell behaviors. Cell adhesion and actin filaments were found to be less established on less stiff surfaces, especially on the surface with an elastic modulus of 51 GPa. Cell growth appeared to be affected by surface mechanical properties. A lower stiffness was generally related to a higher growth rate. Findings in this study broadened our fundamental understanding concerning the mechanosensing of bone cells on stiff substrates. It also suggests that surface mechano-engineering of metallic materials could be a potential strategy to promote osseointegration of such materials for bone-implant applications. Further investigations are proposed to fine tune the ion implantation variables in order to further distinguish the surface-mechanical effect on bone-forming cell activities from the contributions of other surface properties.« less

A mechanism of bone tissue loss in monkeys (BION - 11).

NASA Astrophysics Data System (ADS)

Rodionova, N. V.; Oganov, V. S.

The elucidation of mechanisms of bone tissue loss under the spaceflight conditions remains an actual problem until now It was established that primary reactions to a mechanical stress evolve at the cellular level therefore the main attention of the researchers was aimed at studying bone tissue cells and their interactions With the use of electron microscopy we studied osteoblasts osteocytes osteoclasts and stromal cells in bioptats of the iliac bone crest from monkeys flown on board the satellite guillemotleft BION - 11 guillemotright during 2 weeks The flight samples were compared with the vivarium and simulation controls The functional state of cells was evaluated by the degree of development of organelles for specific biosyntheses rough endoplasmic reticulum Golgy complex nucleus state interrelation with a mineralized matrix The analysis of the obtained results and data of other authors Klein -- Nulend et al 2003 etc permits to suppose that the following sequence of cell interactions underlies the bone tissue loss during mechanical stress microgravity reaction of mechano-sensitive osteocytes to a mechanical stimulus consisting in enhancement of osteolytic processes in cells which results in a partial bone tissue loss along the local unloading Simultaneously the modulating signals are transmitted through a system of canals and processes towards active osteoblasts surface osteocytes and bone marrow stromal cells as well As a reply to a mechanical stimulus there occurs a reduction slowing down of proliferation

Mycobacterium tuberculosis Contaminant Risk on Bone Marrow Aspiration Material from Iliac Bone Patients with Active Tuberculous Spondylitis.

PubMed

Rahyussalim, Ahmad Jabir; Kurniawati, Tri; Rukmana, Andriansjah

2016-01-01

There was a concern on Mycobacterium tuberculosis spreading to the bone marrow, when it was applied on tuberculous spine infection. This research aimed to study the probability of using autologous bone marrow as a source of mesenchymal stem cell for patients with tuberculous spondylitis. As many as nine patients with tuberculous spondylitis were used as samples. During the procedure, the vertebral lesion material and iliac bone marrow aspirates were obtained for acid fast staining, bacteria culture, and PCR (polymerase chain reaction) tests for Mycobacterium tuberculosis at the Clinical Microbiology Laboratory of Faculty of Medicine Universitas Indonesia. This research showed that there was a relationship between diagnostic confirmation of tuberculous spondylitis based on the PCR test and bacterial culture on the solid vertebral lesion material with the PCR test and bacterial culture from the bone marrow aspirates. If the diagnostic confirmation concluded positive results, then there was a higher probability that there would be a positive result for the bone marrow aspirates, so that it was not recommended to use autologous bone marrow as a source of mesenchymal stem cell for patients with tuberculous spondylitis unless the PCR and culture examination of the bone marrow showed a negative result.

Graded porous polyurethane foam: a potential scaffold for oro-maxillary bone regeneration.

PubMed

Giannitelli, S M; Basoli, F; Mozetic, P; Piva, P; Bartuli, F N; Luciani, F; Arcuri, C; Trombetta, M; Rainer, A; Licoccia, S

2015-06-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. Copyright © 2015 Elsevier B.V. All rights reserved.

A bioactive triphasic ceramic-coated hydroxyapatite promotes proliferation and osteogenic differentiation of human bone marrow stromal cells.

PubMed

Nair, Manitha B; Bernhardt, Anne; Lode, Anja; Heinemann, Christiane; Thieme, Sebastian; Hanke, Thomas; Varma, Harikrishna; Gelinsky, Michael; John, Annie

2009-08-01

Hydroxyapatite (HA) ceramics are widely used as bone graft substitutes because of their biocompatibility and osteoconductivity. However, to enhance the success of therapeutic application, many efforts are undertaken to improve the bioactivity of HA. We have developed a triphasic, silica-containing ceramic-coated hydroxyapatite (HASi) and evaluated its performance as a scaffold for cell-based tissue engineering applications. Human bone marrow stromal cells (hBMSCs) were seeded on both HASi and HA scaffolds and cultured with and without osteogenic supplements for a period of 4 weeks. Cellular responses were determined in vitro in terms of cell adhesion, viability, proliferation, and osteogenic differentiation, where both materials exhibited excellent cytocompatibility. Nevertheless, an enhanced rate of cell proliferation and higher levels of both alkaline phosphatase expression and activity were observed for cells cultured on HASi with osteogenic supplements. These findings indicate that the bioactivity of HA endowed with a silica-containing coating has definitely influenced the cellular activity, projecting HASi as a suitable candidate material for bone regenerative therapy.

Dura Mater Stimulates Human Adipose-Derived Stromal Cells to Undergo Bone Formation in Mouse Calvarial Defects

PubMed Central

Levi, Benjamin; Nelson, Emily R.; Li, Shuli; James, Aaron W.; Hyun, Jeong S.; Montoro, Daniel T.; Lee, Min; Glotzbach, Jason P.; Commons, George W.; Longaker, Michael T.

2015-01-01

Human adipose-derived stromal cells (hASCs) have a proven capacity to aid in osseous repair of calvarial defects. However, the bone defect microenvironment necessary for osseous healing is not fully understood. In this study, we postulated that the cell-cell interaction between engrafted ASCs and host dura mater (DM) cells is critical for the healing of calvarial defects. hASCs were engrafted into critical sized calvarial mouse defects. The DM-hASC interaction was manipulated surgically by DM removal or by insertion of a semipermeable or nonpermeable membrane between DM and hASCs. Radiographic, histologic, and gene expression analyses were performed. Next, the hASC-DM interaction is assessed by conditioned media (CM) and coculture assays. Finally, bone morphogenetic protein (BMP) signaling from DM was investigated in vivo using novel BMP-2 and anti-BMP-2/4 slow releasing scaffolds. With intact DM, osseous healing occurs both from host DM and engrafted hASCs. Interference with the DM-hASC interaction dramatically reduced calvarial healing with abrogated BMP-2–Smad-1/5 signaling. Using CM and coculture assays, mouse DM cells stimulated hASC osteogenesis via BMP signaling. Through in vivo manipulation of the BMP-2 pathway, we found that BMP-2 plays an important role in DM stimulation of hASC osteogenesis in the context of calvarial bone healing. BMP-2 supplementation to a defect with disrupted DM allowed for bone formation in a nonhealing defect. DM is an osteogenic cell type that both participates in and stimulates osseous healing in a hASC-engrafted calvarial defect. Furthermore, DM-derived BMP-2 paracrine stimulation appears to play a key role for hASC mediated repair. PMID:21656608

Bone regeneration and stem cells

PubMed Central

Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

2011-01-01

Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed. PMID:21129153

Reciprocal Interactions between Multiple Myeloma Cells and Osteoprogenitor Cells Affect Bone Formation and Tumor Growth

DTIC Science & Technology

2014-10-01

representation of the mechanism of affinity of Ald-PP NPs with bone mineral ( gray , bone mineral; red, Ald; green, PEG; yellow, PLGA). (C) Representative...8217-TCTGCCAGTCCCCCTAGAC-3’ MicroRNAs RNU6B 5’CGCAAGGATGACACGCAAATT-3’ ------------------ URP ------------------ 5’- GTG CAG GGT CCG AGG-3’ hsa-mir-199a

Human fetal bone cells in delivery systems for bone engineering.

PubMed

Tenorio, Diene M H; Scaletta, Corinne; Jaccoud, Sandra; Hirt-Burri, Nathalie; Pioletti, Dominique P; Jaques, Bertrand; Applegate, Lee Ann

2011-11-01

The aim of this study was to culture human fetal bone cells (dedicated cell banks of fetal bone derived from 14 week gestation femurs) within both hyaluronic acid gel and collagen foam, to compare the biocompatibility of both matrices as potential delivery systems for bone engineering and particularly for oral application. Fetal bone cell banks were prepared from one organ donation and cells were cultured for up to 4 weeks within hyaluronic acid (Mesolis®) and collagen foams (TissueFleece®). Cell survival and differentiation were assessed by cell proliferation assays and histology of frozen sections stained with Giemsa, von Kossa and ALP at 1, 2 and 4 weeks of culture. Within both materials, fetal bone cells could proliferate in three-dimensional structure at ∼70% capacity compared to monolayer culture. In addition, these cells were positive for ALP and von Kossa staining, indicating cellular differentiation and matrix production. Collagen foam provides a better structure for fetal bone cell delivery if cavity filling is necessary and hydrogels would permit an injectable technique for difficult to treat areas. In all, there was high biocompatibility, cellular differentiation and matrix deposition seen in both matrices by fetal bone cells, allowing for easy cell delivery for bone stimulation in vivo. Copyright © 2011 John Wiley & Sons, Ltd.

Determination of Corrosion Rate of Artificial Bone Made of Metal at Different pH Conditions using X-Ray Radiography

NASA Astrophysics Data System (ADS)

Sutikno; Handayani, L.; Edi, S. S.; Susilo; Elvira

2018-03-01

The purpose of this research is to observe the mechanism and the rate of corrosion of artificial bone made of metal by using x-ray radiography technique. Artificial bones can be made of metallic materials and composites which are biomaterials. The most commonly used metal for bone graft is stainless steel. The interaction between artificial bone and human tissue will have important medical impacts that need to be observed and examined. This interaction can be a mechanical or chemical interaction. X-ray radiography technique is selected because it uses non-destructive method. This method is done by x-ray radiation exposure on the observed body part. The bone density and bone fracture can be seen on the resulted radiographic film or image on the monitor screen.

Biotemplated syntheses of macroporous materials for bone tissue engineering scaffolds and experiments in vitro and vivo.

PubMed

Li, Xing; Zhao, Yayun; Bing, Yue; Li, Yaping; Gan, Ning; Guo, Zhiyong; Peng, Zhaoxiang; Zhu, Yabin

2013-06-26

The macroporous materials were prepared from the transformation of cuttlebone as biotemplates under hydrothermal reactions and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric/differential thermal analyses (TG-DTA), and scanning electron microscopy (SEM). Cell experimental results showed that the prepared materials as bone tissue engineering scaffolds or fillers had fine biocompatibility suitable for adhesion and proliferation of the hMSCs (human marrow mesenchymal stem cells). Histological analyses were carried out by implanting the scaffolds into a rabbit femur, where the bioresorption, degradation, and biological activity of the scaffolds were observed in the animal body. The prepared scaffolds kept the original three-dimensional frameworks with the ordered porous structures, which made for blood circulation, nutrition supply, and the cells implantation. The biotemplated syntheses could provide a new effective approach to prepare the bone tissue engineering scaffold materials.

Construction of human induced pluripotent stem cell-derived oriented bone matrix microstructure by using in vitro engineered anisotropic culture model.

PubMed

Ozasa, Ryosuke; Matsugaki, Aira; Isobe, Yoshihiro; Saku, Taro; Yun, Hui-Suk; Nakano, Takayoshi

2018-02-01

Bone tissue has anisotropic microstructure based on collagen/biological apatite orientation, which plays essential roles in the mechanical and biological functions of bone. However, obtaining an appropriate anisotropic microstructure during the bone regeneration process remains a great challenging. A powerful strategy for the control of both differentiation and structural development of newly-formed bone is required in bone tissue engineering, in order to realize functional bone tissue regeneration. In this study, we developed a novel anisotropic culture model by combining human induced pluripotent stem cells (hiPSCs) and artificially-controlled oriented collagen scaffold. The oriented collagen scaffold allowed hiPSCs-derived osteoblast alignment and further construction of anisotropic bone matrix which mimics the bone tissue microstructure. To the best of our knowledge, this is the first report showing the construction of bone mimetic anisotropic bone matrix microstructure from hiPSCs. Moreover, we demonstrated for the first time that the hiPSCs-derived osteoblasts possess a high level of intact functionality to regulate cell alignment. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 360-369, 2018. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

Analysis of the Material Properties of Early Chondrogenic Differentiated Adipose-Derived Stromal Cells (ASC) Using an in vitro Three-dimensional Micromass Culture System

PubMed Central

Xu, Yue; Balooch, Guive; Chiou, Michael; Bekerman, Elena; Ritchie, Robert O.; Longaker, Michael T.

2009-01-01

Cartilage is an avascular tissue with only a limited potential to heal and chondrocytes in vitro have poor proliferative capacity. Recently, adipose-derived stromal cells (ASC) have demonstrated a great potential for application to tissue engineering due to their ability to differentiate into cartilage, bone, and fat. In this study, we have utilized a high density three-dimensional (3D) micromass model system of early chondrogenesis with ASC. The material properties of these micromasses showed a significant increase in dynamic and static elastic modulus during the early chondrogenic differentiation process. These data suggest that the 3D micromass culture system represents an in vitro model of early chondrogenesis with dynamic cell signaling interactions associated with the mechanical properties of chondrocyte differentiation. PMID:17543281

Analysis of the material properties of early chondrogenic differentiated adipose-derived stromal cells (ASC) using an in vitro three-dimensional micromass culture system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Yue; Balooch, Guive; Chiou, Michael

2007-07-27

Cartilage is an avascular tissue with only a limited potential to heal and chondrocytes in vitro have poor proliferative capacity. Recently, adipose-derived stromal cells (ASC) have demonstrated a great potential for application to tissue engineering due to their ability to differentiate into cartilage, bone, and fat. In this study, we have utilized a high density three-dimensional (3D) micromass model system of early chondrogenesis with ASC. The material properties of these micromasses showed a significant increase in dynamic and static elastic modulus during the early chondrogenic differentiation process. These data suggest that the 3D micromass culture system represents an in vitromore » model of early chondrogenesis with dynamic cell signaling interactions associated with the mechanical properties of chondrocyte differentiation.« less

Impaired Endothelial Progenitor Cell Mobilization and Dysfunctional Bone Marrow Stroma in Diabetes Mellitus

PubMed Central

Rafii, Shahin; Jaspers, Janneke E.; White, Ian A.; Hooper, Andrea T.; Doevendans, Pieter A.; Verhaar, Marianne C.

2013-01-01

Background Circulating Endothelial Progenitor Cell (EPC) levels are reduced in diabetes mellitus. This may be a consequence of impaired mobilization of EPC from the bone marrow. We hypothesized that under diabetic conditions, mobilization of EPC from the bone marrow to the circulation is impaired –at least partly– due to dysfunction of the bone marrow stromal compartment. Methods Diabetes was induced in mice by streptozotocin injection. Circulating Sca-1+Flk-1+ EPC were characterized and quantified by flow cytometry at baseline and after mobilization with G-CSF/SCF injections. In vivo hemangiogenic recovery was tested by 5-FU challenge. Interaction within the bone marrow environment between CD34+ hematopoietic progenitor cells (HPC) and supporting stroma was assessed by co-cultures. To study progenitor cell–endothelial cell interaction under normoglycemic and hyperglycemic conditions, a co-culture model using E4Orf1-transfected human endothelial cells was employed. Results In diabetic mice, bone marrow EPC levels were unaffected. However, circulating EPC levels in blood were lower at baseline and mobilization was attenuated. Diabetic mice failed to recover and repopulate from 5-FU injection. In vitro, primary cultured bone marrow stroma from diabetic mice was impaired in its capacity to support human CFU-forming HPC. Finally, hyperglycemia hampered the HPC supportive function of endothelial cells in vitro. Conclusion EPC mobilization is impaired under experimental diabetic conditions and our data suggest that diabetes induces alterations in the progenitor cell supportive capacity of the bone marrow stroma, which could be partially responsible for the attenuated EPC mobilization and reduced EPC levels observed in diabetic patients. PMID:23555959

[Experimental study of canine bone marrow mesenchymal stem cells combined with calcium phosphate cement for repair of mandibular bone defects in Beagle dogs].

PubMed

Hu, Yi-cheng; Liu, Xin; Shen, Ji-jia; He, Jia-cai; Chen, Qiao-er

2014-08-01

To evaluate the effects of bone marrow mesenchymal stem cells (BMSCs) combined with calcium phosphate cement (CPC) scaffold for repair of mandibular defect in Beagle dogs. BMSCs were isolated from Beagle dogs and cultured in DMEM plus 10% FBS. The induction effect was determined using alizarin red staining or alkaline phosphate staining at 14-day of culture. BMSCs were added to the CPC scaffold for animal experiments. In vivo, three critical size bone defects were surgically created in each side of the mandible. The bone defects were repaired with BMSCs-CPC (scaffolds with composite seeding cells), CPC (scaffold alone) or no materials (blank group). Two dogs were sacrificed at 4-week and 8-week after operation. Gross observation, X-ray imaging, histologic and histometric analyses were performed to evaluate the level of bone formation. Newly formed bones were detected within all defect sites after operation. The BMSCs-CPC group and CPC group showed increased bone formation compared with the blank group. The BMSCs-CPC group exhibited more bone formation and degradation of the material than the CPC group. The percentage of new bone in the BMSCs-CPC and CPC treated group were significantly higher than that in the control group (P<0.05), while the percentage of new bone in the BMSCs-CPC sites was higher than that in the CPC sites (P<0.01); the percentage of residual material in the BMSCs-CPC sites was lower than that in the CPC sites (P<0.01) 4 weeks and 8 weeks after operation. Using the theory of tissue engineering, BMSCs composite CPC compound is an effective method in promoting new bone regeneration, which has a positive influence on the bone space preservation.

Glycation Contributes to Interaction Between Human Bone Alkaline Phosphatase and Collagen Type I.

PubMed

Halling Linder, Cecilia; Enander, Karin; Magnusson, Per

2016-03-01

Bone is a biological composite material comprised primarily of collagen type I and mineral crystals of calcium and phosphate in the form of hydroxyapatite (HA), which together provide its mechanical properties. Bone alkaline phosphatase (ALP), produced by osteoblasts, plays a pivotal role in the mineralization process. Affinity contacts between collagen, mainly type II, and the crown domain of various ALP isozymes were reported in a few in vitro studies in the 1980s and 1990s, but have not attracted much attention since, although such interactions may have important implications for the bone mineralization process. The objective of this study was to investigate the binding properties of human collagen type I to human bone ALP, including the two bone ALP isoforms B1 and B2. ALP from human liver, human placenta and E. coli were also studied. A surface plasmon resonance-based analysis, supported by electrophoresis and blotting, showed that bone ALP binds stronger to collagen type I in comparison with ALPs expressed in non-mineralizing tissues. Further, the B2 isoform binds significantly stronger to collagen type I in comparison with the B1 isoform. Human bone and liver ALP (with identical amino acid composition) displayed pronounced differences in binding, revealing that post-translational glycosylation properties govern these interactions to a large extent. In conclusion, this study presents the first evidence that glycosylation differences in human ALPs are of crucial importance for protein-protein interactions with collagen type I, although the presence of the ALP crown domain may also be necessary. Different binding affinities among the bone ALP isoforms may influence the mineral-collagen interface, mineralization kinetics, and degree of bone matrix mineralization, which are important factors determining the material properties of bone.

Differences in the developmental origins of the periosteum may influence bone healing.

PubMed

Ichikawa, Y; Watahiki, J; Nampo, T; Nose, K; Yamamoto, G; Irie, T; Mishima, K; Maki, K

2015-08-01

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. 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. 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. 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. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Osteoclastic differentiation and resorption is modulated by bioactive metal ions Co2+, Cu2+ and Cr3+ incorporated into calcium phosphate bone cements

PubMed Central

Bernhardt, Anne; Schamel, Martha; Gbureck, Uwe; Gelinsky, Michael

2017-01-01

Biologically active metal ions in low doses have the potential to accelerate bone defect healing. For successful remodelling the interaction of bone graft materials with both bone-forming osteoblasts and bone resorbing osteoclasts is crucial. In the present study brushite forming calcium phosphate cements (CPC) were doped with Co2+, Cu2+ and Cr3+ and the influence of these materials on osteoclast differentiation and activity was examined. Human osteoclasts were differentiated from human peripheral blood mononuclear cells (PBMC) both on the surface and in indirect contact to the materials on dentin discs. Release of calcium, phosphate and bioactive metal ions was determined using ICP-MS both in the presence and absence of the cells. While Co2+ and Cu2+ showed a burst release, Cr3+ was released steadily at very low concentrations (below 1 μM) and both calcium and phosphate release of the cements was considerably changed in the Cr3+ modified samples. Direct cultivation of PBMC/osteoclasts on Co2+ cements showed lower attached cell number compared to the reference but high activity of osteoclast specific enzymes tartrate resistant acid phosphatase (TRAP), carbonic anhydrase II (CAII) and cathepsin K (CTSK) and significantly increased gene expression of vitronectin receptor. Indirect cultivation with diluted Co2+ cement extracts revealed highest resorbed area compared to all other modifications and the reference. Cu2+ cements had cytotoxic effect on PBMC/osteoclasts during direct cultivation, while indirect cultivation with diluted extracts from Cu2+ cements did not provoke cytotoxic effects but a strictly inhibited resorption. Cr3+ doped cements did not show cytotoxic effects at all. Gene expression and enzyme activity of CTSK was significantly increased in direct culture. Indirect cultivation with Cr3+ doped cements revealed significantly higher resorbed area compared to the reference. In conclusion Cr3+ doped calcium phosphate cements are an innovative cement modification because of their high cytocompatibility and support of active resorption by osteoclasts. PMID:28763481

Elastic interactions between single microcrack and single osteon microstructure of human femur cortical bone

NASA Astrophysics Data System (ADS)

Mansor, N. N.; Daud, R.; Basaruddin, K. S.; Mat, F.; Bajuri, Y.; Ariffin, A. K.

2017-09-01

Inmultiscale Haversian system of cortical bone fracture, a homogenous bone modeling consideration is limited to only one Young modulus was significant for each cortex without having any constituents in that bone. A two dimension model of human femur cortical bone is presented by considering the anatomical positions of four cortices, e.g anterior, posterior, medial and lateral. The Haversian system is modeled under tensile loading by considering the interstitial matrix, osteon and cement line mechanical properties. The interaction between single microcrack and single osteon is evaluated using linear elastic fracture mechanics theory, and was determined using of stress intensity factor, strain energy release rate, and the critical stress intensity factor and critical strain energy release rate parameter. The results indicate that the medial cortex has the highest SIFs while the lowest was posterior cortex. The Young modulus of material was greatly influence the fracture parameters. More stiff the material, the SIF was reduced.

A cellular automata model of bone formation.

PubMed

Van Scoy, Gabrielle K; George, Estee L; Opoku Asantewaa, Flora; Kerns, Lucy; Saunders, Marnie M; Prieto-Langarica, Alicia

2017-04-01

Bone remodeling is an elegantly orchestrated process by which osteocytes, osteoblasts and osteoclasts function as a syncytium to maintain or modify bone. On the microscopic level, bone consists of cells that create, destroy and monitor the bone matrix. These cells interact in a coordinated manner to maintain a tightly regulated homeostasis. It is this regulation that is responsible for the observed increase in bone gain in the dominant arm of a tennis player and the observed increase in bone loss associated with spaceflight and osteoporosis. The manner in which these cells interact to bring about a change in bone quality and quantity has yet to be fully elucidated. But efforts to understand the multicellular complexity can ultimately lead to eradication of metabolic bone diseases such as osteoporosis and improved implant longevity. Experimentally validated mathematical models that simulate functional activity and offer eventual predictive capabilities offer tremendous potential in understanding multicellular bone remodeling. Here we undertake the initial challenge to develop a mathematical model of bone formation validated with in vitro data obtained from osteoblastic bone cells induced to mineralize and quantified at 26 days of culture. A cellular automata model was constructed to simulate the in vitro characterization. Permutation tests were performed to compare the distribution of the mineralization in the cultures and the distribution of the mineralization in the mathematical models. The results of the permutation test show the distribution of mineralization from the characterization and mathematical model come from the same probability distribution, therefore validating the cellular automata model. Copyright © 2017 Elsevier Inc. All rights reserved.

Paracrine interactions between LNCaP prostate cancer cells and bioengineered bone in 3D in vitro culture reflect molecular changes during bone metastasis.

PubMed

Sieh, Shirly; Taubenberger, Anna V; Lehman, Melanie L; Clements, Judith A; Nelson, Colleen C; Hutmacher, Dietmar W

2014-06-01

As microenvironmental factors such as three-dimensionality and cell-matrix interactions are increasingly being acknowledged by cancer biologists, more complex 3D in vitro models are being developed to study tumorigenesis and cancer progression. To better understand the pathophysiology of bone metastasis, we have established and validated a 3D indirect co-culture model to investigate the paracrine interactions between prostate cancer (PCa) cells and human osteoblasts. Co-culture of the human PCa, LNCaP cells embedded within polyethylene glycol hydrogels with human osteoblasts in the form of a tissue engineered bone construct (TEB), resulted in reduced proliferation of LNCaP cells. LNCaP cells in both monoculture and co-culture were responsive to the androgen analog, R1881, as indicated by an increase in the expression (mRNA and/or protein induction) of androgen-regulated genes including prostate specific antigen and fatty acid synthase. Microarray gene expression analysis further revealed an up-regulation of bone markers and other genes associated with skeletal and vasculature development and a significant activation of transforming growth factor β1 downstream genes in LNCaP cells after co-culture with TEB. LNCaP cells co-cultured with TEB also unexpectedly showed similar changes in classical androgen-responsive genes under androgen-deprived conditions not seen in LNCaP monocultures. The molecular changes of LNCaP cells after co-culturing with TEBs suggest that osteoblasts exert a paracrine effect that may promote osteomimicry and modulate the expression of androgen-responsive genes in LNCaP cells. Taken together, we have presented a novel 3D in vitro model that allows the study of cellular and molecular changes occurring in PCa cells and osteoblasts that are relevant to metastatic colonization of bone. This unique in vitro model could also facilitate cancer biologists to dissect specific biological hypotheses via extensive genomic or proteomic assessments to further our understanding of the PCa-bone crosstalk. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Thermogelling chitosan and collagen composite hydrogels initiated with β-glycerophosphate for bone tissue engineering

PubMed Central

Wang, Limin; Stegemann, Jan P.

2010-01-01

Chitosan and collagen type I are naturally-derived materials used as cell carriers because of their ability to mimic the extracellular environment and direct cell function. In this study beta-glycerophosphate (beta-GP), an osteogenic medium supplement and a weak base, was used to simultaneously initiate gelation of pure chitosan, pure collagen, and chitosan-collagen composite materials at physiological pH and temperature. Adult human bone marrow-derived stem cells (hBMSC) encapsulated in such hydrogels at chitosan/collagen ratios of 100/0, 65/35, 25/75, and 0/100 wt% exhibited high viability at day 1 after encapsulation, but DNA content dropped by about half over 12 days in pure chitosan materials while it increased two-fold in materials containing collagen. Collagen-containing materials compacted more strongly and were significantly stiffer than pure chitosan gels. In monolayer culture, exposure of hBMSC to beta-GP resulted in decreased cell metabolic activity that varied with concentration and exposure time, but washing effectively removed excess beta-GP from hydrogels. The presence of chitosan in materials resulted in higher expression of osterix and bone sialoprotein genes in medium with and without osteogenic supplements. Chitosan also increased alkaline phosphatase activity and calcium deposition in osteogenic medium. Chitosan-collagen composite materials have potential as matrices for cell encapsulation and delivery, or as in situ gel-forming materials for tissue repair. PMID:20170955

Thermogelling chitosan and collagen composite hydrogels initiated with beta-glycerophosphate for bone tissue engineering.

PubMed

Wang, Limin; Stegemann, Jan P

2010-05-01

Chitosan and collagen type I are naturally derived materials used as cell carriers because of their ability to mimic the extracellular environment and direct cell function. In this study beta-glycerophosphate (beta-GP), an osteogenic medium supplement and a weak base, was used to simultaneously initiate gelation of pure chitosan, pure collagen, and chitosan-collagen composite materials at physiological pH and temperature. Adult human bone marrow-derived stem cells (hBMSC) encapsulated in such hydrogels at chitosan/collagen ratios of 100/0, 65/35, 25/75, and 0/100 wt% exhibited high viability at day 1 after encapsulation, but DNA content dropped by about half over 12 days in pure chitosan materials while it increased twofold in materials containing collagen. Collagen-containing materials compacted more strongly and were significantly stiffer than pure chitosan gels. In monolayer culture, exposure of hBMSC to beta-GP resulted in decreased cell metabolic activity that varied with concentration and exposure time, but washing effectively removed excess beta-GP from hydrogels. The presence of chitosan in materials resulted in higher expression of osterix and bone sialoprotein genes in medium with and without osteogenic supplements. Chitosan also increased alkaline phosphatase activity and calcium deposition in osteogenic medium. Chitosan-collagen composite materials have potential as matrices for cell encapsulation and delivery, or as in situ gel-forming materials for tissue repair. Copyright 2010 Elsevier Ltd. All rights reserved.

Multiscale characterization of the mineral phase at skeletal sites of breast cancer metastasis.

PubMed

He, Frank; Chiou, Aaron E; Loh, Hyun Chae; Lynch, Maureen; Seo, Bo Ri; Song, Young Hye; Lee, Min Joon; Hoerth, Rebecca; Bortel, Emely L; Willie, Bettina M; Duda, Georg N; Estroff, Lara A; Masic, Admir; Wagermaier, Wolfgang; Fratzl, Peter; Fischbach, Claudia

2017-10-03

Skeletal metastases, the leading cause of death in advanced breast cancer patients, depend on tumor cell interactions with the mineralized bone extracellular matrix. Bone mineral is largely composed of hydroxyapatite (HA) nanocrystals with physicochemical properties that vary significantly by anatomical location, age, and pathology. However, it remains unclear whether bone regions typically targeted by metastatic breast cancer feature distinct HA materials properties. Here we combined high-resolution X-ray scattering analysis with large-area Raman imaging, backscattered electron microscopy, histopathology, and microcomputed tomography to characterize HA in mouse models of advanced breast cancer in relevant skeletal locations. The proximal tibial metaphysis served as a common metastatic site in our studies; we identified that in disease-free bones this skeletal region contained smaller and less-oriented HA nanocrystals relative to ones that constitute the diaphysis. We further observed that osteolytic bone metastasis led to a decrease in HA nanocrystal size and perfection in remnant metaphyseal trabecular bone. Interestingly, in a model of localized breast cancer, metaphyseal HA nanocrystals were also smaller and less perfect than in corresponding bone in disease-free controls. Collectively, these results suggest that skeletal sites prone to tumor cell dissemination contain less-mature HA (i.e., smaller, less-perfect, and less-oriented crystals) and that primary tumors can further increase HA immaturity even before secondary tumor formation, mimicking alterations present during tibial metastasis. Engineered tumor models recapitulating these spatiotemporal dynamics will permit assessing the functional relevance of the detected changes to the progression and treatment of breast cancer bone metastasis.

Multiscale characterization of the mineral phase at skeletal sites of breast cancer metastasis

PubMed Central

Chiou, Aaron E.; Loh, Hyun Chae; Lynch, Maureen; Seo, Bo Ri; Song, Young Hye; Hoerth, Rebecca; Bortel, Emely L.; Willie, Bettina M.; Duda, Georg N.; Masic, Admir; Wagermaier, Wolfgang; Fratzl, Peter; Fischbach, Claudia

2017-01-01

Skeletal metastases, the leading cause of death in advanced breast cancer patients, depend on tumor cell interactions with the mineralized bone extracellular matrix. Bone mineral is largely composed of hydroxyapatite (HA) nanocrystals with physicochemical properties that vary significantly by anatomical location, age, and pathology. However, it remains unclear whether bone regions typically targeted by metastatic breast cancer feature distinct HA materials properties. Here we combined high-resolution X-ray scattering analysis with large-area Raman imaging, backscattered electron microscopy, histopathology, and microcomputed tomography to characterize HA in mouse models of advanced breast cancer in relevant skeletal locations. The proximal tibial metaphysis served as a common metastatic site in our studies; we identified that in disease-free bones this skeletal region contained smaller and less-oriented HA nanocrystals relative to ones that constitute the diaphysis. We further observed that osteolytic bone metastasis led to a decrease in HA nanocrystal size and perfection in remnant metaphyseal trabecular bone. Interestingly, in a model of localized breast cancer, metaphyseal HA nanocrystals were also smaller and less perfect than in corresponding bone in disease-free controls. Collectively, these results suggest that skeletal sites prone to tumor cell dissemination contain less-mature HA (i.e., smaller, less-perfect, and less-oriented crystals) and that primary tumors can further increase HA immaturity even before secondary tumor formation, mimicking alterations present during tibial metastasis. Engineered tumor models recapitulating these spatiotemporal dynamics will permit assessing the functional relevance of the detected changes to the progression and treatment of breast cancer bone metastasis. PMID:28923958

Medium-Term Function of a 3D Printed TCP/HA Structure as a New Osteoconductive Scaffold for Vertical Bone Augmentation: A Simulation by BMP-2 Activation

PubMed Central

Moussa, Mira; Carrel, Jean-Pierre; Scherrer, Susanne; Cattani-Lorente, Maria; Wiskott, Anselm; Durual, Stéphane

2015-01-01

Introduction: A 3D-printed construct made of orthogonally layered strands of tricalcium phosphate (TCP) and hydroxyapatite has recently become available. The material provides excellent osteoconductivity. We simulated a medium-term experiment in a sheep calvarial model by priming the blocks with BMP-2. Vertical bone growth/maturation and material resorption were evaluated. Materials and methods: Titanium hemispherical caps were filled with either bare- or BMP-2 primed constructs and placed onto the calvaria of adult sheep (n = 8). Histomorphometry was performed after 8 and 16 weeks. Results: After 8 weeks, relative to bare constructs, BMP-2 stimulation led to a two-fold increase in bone volume (Bare: 22% ± 2.1%; BMP-2 primed: 50% ± 3%) and a 3-fold decrease in substitute volume (Bare: 47% ± 5%; BMP-2 primed: 18% ± 2%). These rates were still observed at 16 weeks. The new bone grew and matured to a haversian-like structure while the substitute material resorbed via cell- and chemical-mediation. Conclusion: By priming the 3D construct with BMP-2, bone metabolism was physiologically accelerated, that is, enhancing vertical bone growth and maturation as well as material bioresorption. The scaffolding function of the block was maintained, leaving time for the bone to grow and mature to a haversian-like structure. In parallel, the material resorbed via cell-mediated and chemical processes. These promising results must be confirmed in clinical tests.

An automated perfusion bioreactor for the streamlined production of engineered osteogenic grafts.

PubMed

Ding, Ming; Henriksen, Susan S; Wendt, David; Overgaard, Søren

2016-04-01

A computer-controlled perfusion bioreactor was developed for the streamlined production of engineered osteogenic grafts. This system automated the required bioprocesses, from the initial filling of the system through the phases of cell seeding and prolonged cell/tissue culture. Flow through chemo-optic micro-sensors allowed to non-invasively monitor the levels of oxygen and pH in the perfused culture medium throughout the culture period. To validate its performance, freshly isolated ovine bone marrow stromal cells were directly seeded on porous scaffold granules (hydroxyapatite/β-tricalcium-phosphate/poly-lactic acid), bypassing the phase of monolayer cell expansion in flasks. Either 10 or 20 days after culture, engineered cell-granule grafts were implanted in an ectopic mouse model to quantify new bone formation. After four weeks of implantation, histomorphometry showed more bone in bioreactor-generated grafts than cell-free granule controls, while bone formation did not show significant differences between 10 days and 20 days of incubation. The implanted granules without cells had no bone formation. This novel perfusion bioreactor has revealed the capability of activation larger viable bone graft material, even after shorter incubation time of graft material. This study has demonstrated the feasibility of engineering osteogenic grafts in an automated bioreactor system, laying the foundation for a safe, regulatory-compliant, and cost-effective manufacturing process. © 2015 Wiley Periodicals, Inc.

Combinatorial Gata2 and Sca1 expression defines hematopoietic stem cells in the bone marrow niche

PubMed Central

Suzuki, Norio; Ohneda, Osamu; Minegishi, Naoko; Nishikawa, Mitsuo; Ohta, Takayuki; Takahashi, Satoru; Engel, James Douglas; Yamamoto, Masayuki

2006-01-01

The interaction between stem cells and their supportive microenvironment is critical for their maintenance, function, and survival. Whereas hematopoietic stem cells (HSCs) are among the best characterized of tissue stem cells, their precise site of residence (referred to as the niche) in the adult bone marrow has not been precisely defined. In this study, we found that a Gata2 promoter directs activity in all HSCs. We show that HSCs can be isolated efficiently from bone marrow cells by following Gata2-directed GFP fluorescence, and that they can also be monitored in vivo. Each individual GFP-positive cell lay in a G0/G1 cell cycle state, in intimate contact with osteoblasts beside the endosteum, at the edge of the bone marrow. We conclude that the HSC niche is composed of solitary cells and that adult bone marrow HSC are not clustered. PMID:16461905

Prostate cancer cell-stromal cell crosstalk via FGFR1 mediates antitumor activity of dovitinib in bone metastases.

PubMed

Wan, Xinhai; Corn, Paul G; Yang, Jun; Palanisamy, Nallasivam; Starbuck, Michael W; Efstathiou, Eleni; Li Ning Tapia, Elsa M; Tapia, Elsa M Li-Ning; Zurita, Amado J; Aparicio, Ana; Ravoori, Murali K; Vazquez, Elba S; Robinson, Dan R; Wu, Yi-Mi; Cao, Xuhong; Iyer, Matthew K; McKeehan, Wallace; Kundra, Vikas; Wang, Fen; Troncoso, Patricia; Chinnaiyan, Arul M; Logothetis, Christopher J; Navone, Nora M

2014-09-03

Bone is the most common site of prostate cancer (PCa) progression to a therapy-resistant, lethal phenotype. We found that blockade of fibroblast growth factor receptors (FGFRs) with the receptor tyrosine kinase inhibitor dovitinib has clinical activity in a subset of men with castration-resistant PCa and bone metastases. Our integrated analyses suggest that FGF signaling mediates a positive feedback loop between PCa cells and bone cells and that blockade of FGFR1 in osteoblasts partially mediates the antitumor activity of dovitinib by improving bone quality and by blocking PCa cell-bone cell interaction. These findings account for clinical observations such as reductions in lesion size and intensity on bone scans, lymph node size, and tumor-specific symptoms without proportional declines in serum prostate-specific antigen concentration. Our findings suggest that targeting FGFR has therapeutic activity in advanced PCa and provide direction for the development of therapies with FGFR inhibitors. Copyright © 2014, American Association for the Advancement of Science.

Effect of modified pectin molecules on the growth of bone cells.

PubMed

Kokkonen, Hanna E; Ilvesaro, Joanna M; Morra, Marco; Schols, Henk A; Tuukkanen, Juha

2007-02-01

The aim of this study was to investigate molecular candidates for bone implant nanocoatings, which could improve biocompatibility of implant materials. Primary rat bone cells and murine preosteoblastic MC3T3-E1 cells were cultured on enzymatically modified hairy regions (MHR-A and MHR-B) of apple pectins. MHRs were covalently attached to tissue culture polystyrene (TCPS) or glass. Uncoated substrata or bone slices were used as controls. Cell attachment, proliferation, and differentiation were investigated with fluorescence and confocal microscopy. Bone cells seem to prefer MHR-B coating to MHR-A coating. On MHR-A samples, the overall numbers as well as proportions of active osteoclasts were diminished compared to those on MHR-B, TCPS, or bone. Focal adhesions indicating attachment of the osteoblastic cells were detected on MHR-B and uncoated controls but not on MHR-A. These results demonstrate the possibility to modify surfaces with pectin nanocoatings.

Si-doping bone composite based on protein template-mediated assembly for enhancing bone regeneration

NASA Astrophysics Data System (ADS)

Yang, Qin; Du, Yingying; Wang, Yifan; Wang, Zhiying; Ma, Jun; Wang, Jianglin; Zhang, Shengmin

2017-06-01

Bio-inspired hybrid materials that contain organic and inorganic networks interpenetration at the molecular level have been a particular focus of interest on designing novel nanoscale composites. Here we firstly synthesized a series of hybrid bone composites, silicon-hydroxyapatites/silk fibroin/collagen, based on a specific molecular assembled strategy. Results of material characterization confirmed that silicate had been successfully doped into nano-hydroxyapatite lattice. In vitro evaluation at the cellular level clearly showed that these Si-doped composites were capable of promoting the adhesion and proliferation of rat mesenchymal stem cells (rMSCs), extremely enhancing osteoblastic differentiation of rMSCs compared with silicon-free composite. More interestingly, we found there was a critical point of silicon content in the composition on regulating multiple cell behaviors. In vivo animal evaluation further demonstrated that Si-doped composites enabled to significantly improve the repair of cranial bone defect. Consequently, our current work not only suggests fabricating a potential bone repair materials by integrating element-doping and molecular assembled strategy in one system, but also paves a new way for constructing multi-functional composite materials in the future.

Pore size regulates cell and tissue interactions with PLGA-CaP scaffolds used for bone engineering.

PubMed

Sicchieri, Luciana Gonçalves; Crippa, Grasiele Edilaine; de Oliveira, Paulo Tambasco; Beloti, Marcio Mateus; Rosa, Adalberto Luiz

2012-02-01

A common subject in bone tissue engineering is the need for porous scaffolds to support cell and tissue interactions aiming at repairing bone tissue. As poly(lactide-co-glycolide)-calcium phosphate (PLGA-CaP) scaffolds can be manufactured with different pore sizes, the aim of this study was to evaluate the effect of pore diameter on osteoblastic cell responses and bone tissue formation. Scaffolds were prepared with 85% porosity, with pore diameters in the ranges 470-590, 590-850 and 850-1200 µm. Rat bone marrow stem cells differentiated into osteoblasts were cultured on the scaffolds for up to 10 days to evaluate cell growth, alkaline phosphatase (ALP) activity and the gene expression of the osteoblast markers RUNX2, OSX, COL, MSX2, ALP, OC and BSP by real-time PCR. Scaffolds were implanted in critical size rat calvarial defects for 2, 4, and 8 weeks for histomorphometric analysis. Cell growth and ALP activity were not affected by the pore size; however, there was an increase in the gene expression of osteoblastic markers with the increase in the pore sizes. At 2 weeks all scaffolds displayed a similar amount of bone and blood vessels formation. At 4 and 8 weeks much more bone formation and an increased number of blood vessels were observed in scaffolds with pores of 470-590 µm. These results show that PLGA-CaP is a promising biomaterial for bone engineering. However, ideally, combinations of larger (-1000 µm) and smaller (-500 µm) pores in a single scaffold would optimize cellular and tissue responses during bone healing. Copyright © 2011 John Wiley & Sons, Ltd.

A review of fibrin and fibrin composites for bone tissue engineering

PubMed Central

Noori, Alireza; Ashrafi, Seyed Jamal; Vaez-Ghaemi, Roza; Hatamian-Zaremi, Ashraf; Webster, Thomas J

2017-01-01

Tissue engineering has emerged as a new treatment approach for bone repair and regeneration seeking to address limitations associated with current therapies, such as autologous bone grafting. While many bone tissue engineering approaches have traditionally focused on synthetic materials (such as polymers or hydrogels), there has been a lot of excitement surrounding the use of natural materials due to their biologically inspired properties. Fibrin is a natural scaffold formed following tissue injury that initiates hemostasis and provides the initial matrix useful for cell adhesion, migration, proliferation, and differentiation. Fibrin has captured the interest of bone tissue engineers due to its excellent biocompatibility, controllable biodegradability, and ability to deliver cells and biomolecules. Fibrin is particularly appealing because its precursors, fibrinogen, and thrombin, which can be derived from the patient’s own blood, enable the fabrication of completely autologous scaffolds. In this article, we highlight the unique properties of fibrin as a scaffolding material to treat bone defects. Moreover, we emphasize its role in bone tissue engineering nanocomposites where approaches further emulate the natural nanostructured features of bone when using fibrin and other nanomaterials. We also review the preparation methods of fibrin glue and then discuss a wide range of fibrin applications in bone tissue engineering. These include the delivery of cells and/or biomolecules to a defect site, distributing cells, and/or growth factors throughout other pre-formed scaffolds and enhancing the physical as well as biological properties of other biomaterials. Thoughts on the future direction of fibrin research for bone tissue engineering are also presented. In the future, the development of fibrin precursors as recombinant proteins will solve problems associated with using multiple or single-donor fibrin glue, and the combination of nanomaterials that allow for the incorporation of biomolecules with fibrin will significantly improve the efficacy of fibrin for numerous bone tissue engineering applications. PMID:28761338

A review of fibrin and fibrin composites for bone tissue engineering.

PubMed

Noori, Alireza; Ashrafi, Seyed Jamal; Vaez-Ghaemi, Roza; Hatamian-Zaremi, Ashraf; Webster, Thomas J

2017-01-01

Tissue engineering has emerged as a new treatment approach for bone repair and regeneration seeking to address limitations associated with current therapies, such as autologous bone grafting. While many bone tissue engineering approaches have traditionally focused on synthetic materials (such as polymers or hydrogels), there has been a lot of excitement surrounding the use of natural materials due to their biologically inspired properties. Fibrin is a natural scaffold formed following tissue injury that initiates hemostasis and provides the initial matrix useful for cell adhesion, migration, proliferation, and differentiation. Fibrin has captured the interest of bone tissue engineers due to its excellent biocompatibility, controllable biodegradability, and ability to deliver cells and biomolecules. Fibrin is particularly appealing because its precursors, fibrinogen, and thrombin, which can be derived from the patient's own blood, enable the fabrication of completely autologous scaffolds. In this article, we highlight the unique properties of fibrin as a scaffolding material to treat bone defects. Moreover, we emphasize its role in bone tissue engineering nanocomposites where approaches further emulate the natural nanostructured features of bone when using fibrin and other nanomaterials. We also review the preparation methods of fibrin glue and then discuss a wide range of fibrin applications in bone tissue engineering. These include the delivery of cells and/or biomolecules to a defect site, distributing cells, and/or growth factors throughout other pre-formed scaffolds and enhancing the physical as well as biological properties of other biomaterials. Thoughts on the future direction of fibrin research for bone tissue engineering are also presented. In the future, the development of fibrin precursors as recombinant proteins will solve problems associated with using multiple or single-donor fibrin glue, and the combination of nanomaterials that allow for the incorporation of biomolecules with fibrin will significantly improve the efficacy of fibrin for numerous bone tissue engineering applications.

Bone-repair properties of biodegradable hydroxyapatite nano-rod superstructures

NASA Astrophysics Data System (ADS)

D'Elía, Noelia L.; Mathieu, Colleen; Hoemann, Caroline D.; Laiuppa, Juan A.; Santillán, Graciela E.; Messina, Paula V.

2015-11-01

Nano-hydroxyapatite (nano-HAp) materials show an analogous chemical composition to the biogenic mineral components of calcified tissues and depending on their topography they may mimic the specific arrangement of the crystals in bone. In this work, we have evaluated the potential of four synthesized nano-HAp superstructures for the in vitro conditions of bone-repair. Experiments are underway to investigate the effects of the material microstructure, surface roughness and hydrophilicity on their osseo-integration, osteo-conduction and osteo-induction abilities. Materials were tested in the presence of both, rat primary osteoblasts and rabbit mesenchymal stem cells. The following aspects are discussed: (i) cytotoxicity and material degradation; (ii) rat osteoblast spreading, proliferation and differentiation; and (iii) rabbit mesenchymal stem cell adhesion on nano-HAp and nano-HAp/collagen type I coatings. We effectively prepared a material based on biomimetic HAp nano-rods displaying the appropriate surface topography, hydrophilicity and degradation properties to induce the in vitro desired cellular responses for bone bonding and healing. Cells seeded on the selected material readily attached, proliferated and differentiated, as confirmed by cell viability, mitochondrial metabolic activity, alkaline phosphatase (ALP) activity and cytoskeletal integrity analysis by immunofluorescence localization of alpha-smooth muscle actin (α-SMA) protein. These results highlight the influence of material's surface characteristics to determine their tissue regeneration potential and their future use in engineering osteogenic scaffolds for orthopedic implants.Nano-hydroxyapatite (nano-HAp) materials show an analogous chemical composition to the biogenic mineral components of calcified tissues and depending on their topography they may mimic the specific arrangement of the crystals in bone. In this work, we have evaluated the potential of four synthesized nano-HAp superstructures for the in vitro conditions of bone-repair. Experiments are underway to investigate the effects of the material microstructure, surface roughness and hydrophilicity on their osseo-integration, osteo-conduction and osteo-induction abilities. Materials were tested in the presence of both, rat primary osteoblasts and rabbit mesenchymal stem cells. The following aspects are discussed: (i) cytotoxicity and material degradation; (ii) rat osteoblast spreading, proliferation and differentiation; and (iii) rabbit mesenchymal stem cell adhesion on nano-HAp and nano-HAp/collagen type I coatings. We effectively prepared a material based on biomimetic HAp nano-rods displaying the appropriate surface topography, hydrophilicity and degradation properties to induce the in vitro desired cellular responses for bone bonding and healing. Cells seeded on the selected material readily attached, proliferated and differentiated, as confirmed by cell viability, mitochondrial metabolic activity, alkaline phosphatase (ALP) activity and cytoskeletal integrity analysis by immunofluorescence localization of alpha-smooth muscle actin (α-SMA) protein. These results highlight the influence of material's surface characteristics to determine their tissue regeneration potential and their future use in engineering osteogenic scaffolds for orthopedic implants. Electronic supplementary information (ESI) available: Calculation of roughness parameters Rz, Rz,max, and Rz, prom. Nano-HAp powder degradation after immersion in phosphate buffer (pH = 7.4). Optical phase contrast microphotographs of MSC adhesion on nano-HAp and nano-HAp/Co I coatings at different concentrations. Laser scanning confocal microphotographs of MSCs' α-SMA expression spreading on large amounts of nano-HAp (MI) coatings. Immunofluorescence microphotograph analysis by image software. See DOI: 10.1039/c5nr04850h

Application of platelet-rich plasma with stem cells in bone and periodontal tissue engineering

PubMed Central

Fernandes, Gabriela; Yang, Shuying

2016-01-01

Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors (GFs), it makes stem cells the ideal agents for bone regeneration. Furthermore, platelet-rich plasma (PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future. PMID:28018706

Guided bone augmentation using ceramic space-maintaining devices: the impact of chemistry

PubMed Central

Anderud, Jonas; Abrahamsson, Peter; Jimbo, Ryo; Isaksson, Sten; Adolfsson, Erik; Malmström, Johan; Naito, Yoshihito; Wennerberg, Ann

2015-01-01

The purpose of the study was to evaluate histologically, whether vertical bone augmentation can be achieved using a hollow ceramic space maintaining device in a rabbit calvaria model. Furthermore, the chemistry of microporous hydroxyapatite and zirconia were tested to determine which of these two ceramics are most suitable for guided bone generation. 24 hollow domes in two different ceramic materials were placed subperiosteal on rabbit skull bone. The rabbits were sacrificed after 12 weeks and the histology results were analyzed regarding bone-to-material contact and volume of newly formed bone. The results suggest that the effect of the microporous structure of hydroxyapatite seems to facilitate for the bone cells to adhere to the material and that zirconia enhance a slightly larger volume of newly formed bone. In conclusion, the results of the current study demonstrated that ceramic space maintaining devices permits new bone formation and osteoconduction within the dome. PMID:25792855

Resorption behavior of a nanostructured bone substitute: in vitro investigation and clinical application.

PubMed

Reichert, Christoph; Götz, Werner; Reimann, Susanne; Keilig, Ludger; Hagner, Martin; Bourauel, Christoph; Jäger, Andreas

2013-03-01

To develop an in vitro assay for quantitative analysis of the degradation to which a bone substitute is exposed by osteoclasts. The aim of establishing this method was to improve the predictability of carrying out tooth movements via bone substitutes and to provide a basis for verification in exemplary clinical cases. After populating a bone substitute (NanoBone®; ArtOss, Germany) with osteoclastic cells, inductively-coupled mass spectrometry was used to evaluate changing calcium levels in the culture medium as a marker of resorption activity. It was observed that calcium levels increased substantially in the culture medium with the cells populating the bone substitute. This in vitro assay is a valid method that can assist clinicians in selecting the appropriate materials for certain patients. While tooth movements occurring through this material were successful, uncertainty about the approach will remain as long-term results are not available.

Low-expression of E-cadherin in leukaemia cells causes loss of homophilic adhesion and promotes cell growth.

PubMed

Rao, Qing; Wang, Ji-Ying; Meng, Jihong; Tang, Kejing; Wang, Yanzhong; Wang, Min; Xing, Haiyan; Tian, Zheng; Wang, Jianxiang

2011-09-01

E-cadherin (epithelial cadherin) belongs to the calcium-dependent adhesion molecule superfamily and is implicated in the interactions of haematopoietic progenitors and bone marrow stromal cells. Adhesion capacity to bone marrow stroma was impaired for leukaemia cells, suggesting that a breakdown of adhesive mechanisms governed by an adhesion molecule may exist in leukaemic microenvironment. We previously found that E-cadherin was low expressed in primary acute leukaemia cells compared with normal bone marrow mononuclear cells. In this study, we investigate the functional importance of low E-cadherin expression in leukaemia cell behaviours and investigate its effects in the abnormal interaction of leukaemic cells with stromal cells. After expression of E-cadherin was restored by a demethylating agent in leukaemia cells, E-cadherin-specific adhesion was enhanced. Additionally, siRNA (small interfering RNA)-mediated silencing of E-cadherin in Raji cells resulted in a reduction of cell homophilic adhesion and enhancement of cell proliferation and colony formation. These results suggest that low expression of E-cadherin contributes to the vigorous growth and transforming ability of leukaemic cells.

Preclinical studies in support of defibrotide for the treatment of multiple myeloma and other neoplasias.

PubMed

Mitsiades, Constantine S; Rouleau, Cecile; Echart, Cinara; Menon, Krishna; Teicher, Beverly; Distaso, Maria; Palumbo, Antonio; Boccadoro, Mario; Anderson, Kenneth C; Iacobelli, Massimo; Richardson, Paul G

2009-02-15

Defibrotide, an orally bioavailable polydisperse oligonucleotide, has promising activity in hepatic veno-occlusive disease, a stem cell transplantation-related toxicity characterized by microangiopathy. The antithrombotic properties of defibrotide and its minimal hemorrhagic risk could serve for treatment of cancer-associated thrombotic complications. Given its cytoprotective effect on endothelium, we investigated whether defibrotide protects tumor cells from cytotoxic antitumor agents. Further, given its antiadhesive properties, we evaluated whether defibrotide modulates the protection conferred to multiple myeloma cells by bone marrow stromal cells. Defibrotide lacks significant single-agent in vitro cytotoxicity on multiple myeloma or solid tumor cells and does not attenuate their in vitro response to dexamethasone, bortezomib, immunomodulatory thalidomide derivatives, and conventional chemotherapeutics, including melphalan and cyclophosphamide. Importantly, defibrotide enhances in vivo chemosensitivity of multiple myeloma and mammary carcinoma xenografts in animal models. In cocultures of multiple myeloma cells with bone marrow stromal cells in vitro, defibrotide enhances the multiple myeloma cell sensitivity to melphalan and dexamethasone, and decreases multiple myeloma-bone marrow stromal cell adhesion and its sequelae, including nuclear factor-kappaB activation in multiple myeloma and bone marrow stromal cells, and associated cytokine production. Moreover, defibrotide inhibits expression and/or function of key mediators of multiple myeloma interaction with bone marrow stromal cell and endothelium, including heparanase, angiogenic cytokines, and adhesion molecules. Defibrotide's in vivo chemosensitizing properties and lack of direct in vitro activity against tumor cells suggest that it favorably modulates antitumor interactions between bone marrow stromal cells and endothelia in the tumor microenvironment. These data support clinical studies of defibrotide in combination with conventional and novel therapies to potentially improve patient outcome in multiple myeloma and other malignancies.

Application of Petri Nets in Bone Remodeling

PubMed Central

Li, Lingxi; Yokota, Hiroki

2009-01-01

Understanding a mechanism of bone remodeling is a challenging task for both life scientists and model builders, since this highly interactive and nonlinear process can seldom be grasped by simple intuition. A set of ordinary differential equations (ODEs) have been built for simulating bone formation as well as bone resorption. Although solving ODEs numerically can provide useful predictions for dynamical behaviors in a continuous time frame, an actual bone remodeling process in living tissues is driven by discrete events of molecular and cellular interactions. Thus, an event-driven tool such as Petri nets (PNs), which may dynamically and graphically mimic individual molecular collisions or cellular interactions, seems to augment the existing ODE-based systems analysis. Here, we applied PNs to expand the ODE-based approach and examined discrete, dynamical behaviors of key regulatory molecules and bone cells. PNs have been used in many engineering areas, but their application to biological systems needs to be explored. Our PN model was based on 8 ODEs that described an osteoprotegerin linked molecular pathway consisting of 4 types of bone cells. The models allowed us to conduct both qualitative and quantitative evaluations and evaluate homeostatic equilibrium states. The results support that application of PN models assists understanding of an event-driven bone remodeling mechanism using PN-specific procedures such as places, transitions, and firings. PMID:19838338

Accelerated Tumor Cell Death by Angiogenic Modifiers

DTIC Science & Technology

2004-08-01

factors; extracellular matrix; 3-D cell culture; cancer metastasis Running title: Tumor-Stroma Interaction Abbreviations: BSP, bone sialoprotein ; ECM...such as osteocalcin (OC), bone sialoprotein (BSP), osteopontin (OPN), osteonectin (ON or SPARC), 18 osteoprotegerin (OPG), PTHrP, M-CSF, RANK and...Waltregny, D., Bellahcene, A., Van Riet, I., Fisher, L. W., Young, M., Fernandez, P. and et al. Prognostic value of bone sialoprotein expression in

A perfusion bioreactor system efficiently generates cell-loaded bone substitute materials for addressing critical size bone defects.

PubMed

Kleinhans, Claudia; Mohan, Ramkumar Ramani; Vacun, Gabriele; Schwarz, Thomas; Haller, Barbara; Sun, Yang; Kahlig, Alexander; Kluger, Petra; Finne-Wistrand, Anna; Walles, Heike; Hansmann, Jan

2015-09-01

Critical size bone defects and non-union fractions are still challenging to treat. Cell-loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor-made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L-lactide-co-caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans. © 2015 The Authors. Biotechnology Journal published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial Licence, which permits use, distribution and reproduction in any medium, provided the Contribution is properly cited and is not used for commercial purpose.

Natural Polymer-Cell Bioconstructs for Bone Tissue Engineering.

PubMed

Titorencu, Irina; Albu, Madalina Georgiana; Nemecz, Miruna; Jinga, Victor V

2017-01-01

The major goal of bone tissue engineering is to develop bioconstructs which substitute the functionality of damaged natural bone structures as much as possible if critical-sized defects occur. Scaffolds that mimic the structure and composition of bone tissue and cells play a pivotal role in bone tissue engineering applications. First, composition, properties and in vivo synthesis of bone tissue are presented for the understanding of bone formation. Second, potential sources of osteoprogenitor cells have been investigated for their capacity to induce bone repair and regeneration. Third, taking into account that the main property to qualify one scaffold as a future bioconstruct for bone tissue engineering is the biocompatibility, the assessments which prove it are reviewed in this paper. Forth, various types of natural polymer- based scaffolds consisting in proteins, polysaccharides, minerals, growth factors etc, are discussed, and interaction between scaffolds and cells which proved bone tissue engineering concept are highlighted. Finally, the future perspectives of natural polymer-based scaffolds for bone tissue engineering are considered. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

S100A8/A9 (Calprotectin) Is Critical for Development of Glomerulonephritis and Promotes Inflammatory Leukocyte–Renal Cell Interactions

PubMed Central

Pepper, Ruth J.; Wang, Hsu-Han; Rajakaruna, Gayathri K.; Papakrivopoulou, Eugenia; Vogl, Thomas; Pusey, Charles D.; Cook, H. Terence; Salama, Alan D.

2015-01-01

Glomerulonephritis is a common cause of end-stage renal disease. Infiltrating leukocytes interacting with renal cells play a critical role during the initiation and progression of glomerulonephritis, but the exact mechanisms are not clearly defined. By using the murine model of nephrotoxic nephritis, we investigated the role of S100A8/A9 [myeloid-related protein (MRP) 8/14, calprotectin] in promoting glomerulonephritis. In nephrotoxic nephritis, wild-type (WT) mice with glomerulonephritis have elevated serum levels of S100A8/A9, whereas mice deficient in MRP14 (S100a9−/−), and hence S100A8/A9, are significantly protected from disease. By using bone marrow transplants, we showed that MRP14 deficiency is required in both the hemopoietic and intrinsic cells for the protective effect. In vitro, both the WT bone marrow–derived macrophages and renal mesangial cells stimulated with S100A8/A9 secrete IL-6, CXCL1, and tumor necrosis factor α; however, Mrp14−/− cells exhibit significantly blunted proinflammatory responses. The interaction of WT bone marrow–derived macrophages with renal microvascular endothelial cells results in increased levels of monocyte chemotactic protein 1, IL-8, and IL-6 cytokines, which is attenuated in Mrp14−/− bone marrow–derived macrophages. Data shows that S100A8/A9 plays a critical role during glomerulonephritis, exerting and amplifying autocrine and paracrine proinflammatory effects on bone marrow–derived macrophages, renal endothelial cells, and mesangial cells. Therefore, complete S100A8/A9 blockade may be a new therapeutic target in glomerulonephritis. PMID:25759267

Potential of inherent RGD containing silk fibroin-poly (Є-caprolactone) nanofibrous matrix for bone tissue engineering.

PubMed

Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Kim, Hae-Won; Bhattacharya, Debasis; Maiti, T K; Kundu, S C

2016-02-01

The current study deals with the fabrication and characterization of blended nanofibrous scaffolds of tropical tasar silk fibroin of Antheraea mylitta and poly (Є-caprolactone) to act as an ideal scaffold for bone regeneration. The use of poly (Є-caprolactone) in osteogenesis is well-recognized. At the same time, the osteoconductive nature of the non-mulberry tasar fibroin is also established due to its internal integrin binding peptide RGD (Arg-Gly-Asp) sequences, which enhance cellular interaction and proliferation. Considering that the materials have the required and favorable properties, the blends are formed using an equal volume ratio of fibroin (2 and 4 wt%) and poly (Є-caprolactone) solution (10 wt%) to fabricate nanofibers. The nanofibers possess an average diameter of 152 ± 18 nm (2 % fibroin/PCL) and 175 ± 15 nm (4% fibroin/PCL). The results of Fourier transform infrared spectroscopy substantiates the preservation of the secondary structure of the fibroin in the blends indicating the structural stability of the neo-matrix. With an increase in the fibroin percentage, the hydrophobicity and thermal stability of the matrices as measured from melting temperature Tm (using DSC) decrease, while the mechanical strength is improved. The blended nanofibrous scaffolds are biodegradable, and support the viability and proliferation of human osteoblast-like cells as observed through scanning electron and confocal microscopes. Alkaline phosphatase assay indicates the cell proliferation and the generation of the neo-bone matrix. Taken together, these findings illustrate that the silk-poly (Є-caprolactone) blended nanofibrous scaffolds have an excellent prospect as scaffolding material in bone tissue engineering.

Skeletal stem cell and bone implant interactions are enhanced by LASER titanium modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisti, Karin E., E-mail: karinellensisti@gmail.com; Biomaterials Group, Institute of Chemistry, São Paulo State University; Federal University of Mato Grosso do Sul

Purpose: To evaluate the osteo-regenerative potential of Titanium (Ti) modified by Light Amplification by Stimulated Emission of Radiation (LASER) beam (Yb-YAG) upon culture with human Skeletal Stem Cells (hSSCs{sup 1}). Methods: Human skeletal cell populations were isolated from the bone marrow of haematologically normal patients undergoing primary total hip replacement following appropriate consent. STRO-1{sup +} hSSC{sup 1} function was examined for 10 days across four groups using Ti discs: i) machined Ti surface group in basal media (Mb{sup 2}), ii) machined Ti surface group in osteogenic media (Mo{sup 3}), iii) LASER-modified Ti group in basal media (Lb{sup 4}) and, iv)more » LASER-modified Ti group in osteogenic media (Lo{sup 5}). Molecular analysis and qRT-PCR as well as functional analysis including biochemistry (DNA, Alkaline Phosphatase (ALP{sup 6}) specific activity), live/dead immunostaining (Cell Tracker Green (CTG{sup 7})/Ethidium Homodimer-1 (EH-1{sup 8})), and fluorescence staining (for vinculin and phalloidin) were undertaken. Inverted, confocal and Scanning Electron Microscopy (SEM) approaches were used to characterise cell adherence, proliferation, and phenotype. Results: Enhanced cell spreading and morphological rearrangement, including focal adhesions were observed following culture of hSSCs{sup 1} on LASER surfaces in both basal and osteogenic conditions. Biochemical analysis demonstrated enhanced ALP{sup 6} specific activity on the hSSCs{sup 1}-seeded on LASER-modified surface in basal culture media. Molecular analysis demonstrated enhanced ALP{sup 6} and osteopontin expression on titanium LASER treated surfaces in basal conditions. SEM, inverted microscopy and confocal laser scanning microscopy confirmed extensive proliferation and migration of human bone marrow stromal cells on all surfaces evaluated. Conclusions: LASER-modified Ti surfaces modify the behaviour of hSSCs.{sup 1} In particular, SSC{sup 1} adhesion, osteogenic gene expression, cell morphology and cytoskeleton structure were affected. The current studies show Ti LASER modification can enhance the osseointegration between Ti and skeletal cells, with important implications for orthopaedic application. - Highlights: • Bone stem cells on LASER Ti surface display enhanced cell growth and viability. • Bone stem cells on LASER Ti surface exhibit marked biocompatibility. • Human bone stem cells on LASER Ti surface exhibit altered morphology. • LASER Ti enhance osteogenic differentiation of human bone skeletal stem cells. • LASER Ti provides a unique approach to enhance osseointegration with the material.« less

Expression of Fas and Fas-ligand in donor hematopoietic stem and progenitor cells is dissociated from the sensitivity to apoptosis.

PubMed

Pearl-Yafe, Michal; Yolcu, Esma S; Stein, Jerry; Kaplan, Ofer; Shirwan, Haval; Yaniv, Isaac; Askenasy, Nadir

2007-10-01

The interaction between the Fas receptor and its cognate ligand (FasL) has been implicated in the mutual suppression of donor and host hematopoietic cells after transplantation. Following the observation of deficient early engraftment of Fas and FasL-defective donor cells and recipients, we determined the role of the Fas-FasL interaction. Donor cells were recovered after syngeneic (CD45.1-->CD45.2) transplants from various organs and assessed for expression of Fas/FasL in reference to lineage markers, carboxyfluorescein succinimidyl ester dilution, Sca-1 and c-kit expression. Naïve and bone marrow-homed cells were challenged for apoptosis ex vivo. The Fas receptor and ligand were markedly upregulated to 40% to 60% (p < 0.001 vs 5-10% in naïve cells) within 2 days after syngeneic transplantation, while residual host cells displayed modest and delayed upregulation of these molecules ( approximately 10%). All lin(-)Sca(+)c-kit(+) cells were Fas(+)FasL(+), including 95% of Sca-1(+) and 30% of c-kit(+) cells. Fas and FasL expression varied in donor cells that homed to bone marrow, spleen, liver and lung, and was induced by interaction with the stroma, irradiation, cell cycling, and differentiation. Bone marrow-homed donor cells challenged with supralethal doses of FasL were insensitive to apoptosis (3.2% +/- 1% vs 38% +/- 5% in naïve bone marrow cells), and engraftment was not affected by pretransplantation exposure of donor cells to an apoptotic challenge with FasL. There was no evidence of Fas-mediated suppression of donor and host cell activity after transplantation. Resistance to Fas-mediated apoptosis evolves as a functional characteristic of hematopoietic reconstituting stem and progenitor cells, providing them competitive engraftment advantage over committed progenitors.

Giant cells around bone biomaterials: Osteoclasts or multi-nucleated giant cells?

PubMed

Miron, Richard J; Zohdi, Hamoon; Fujioka-Kobayashi, Masako; Bosshardt, Dieter D

2016-12-01

Recently accumulating evidence has put into question the role of large multinucleated giant cells (MNGCs) around bone biomaterials. While cells derived from the monocyte/macrophage lineage are one of the first cell types in contact with implanted biomaterials, it was originally thought that specifically in bone tissues, all giant cells were bone-resorbing osteoclasts whereas foreign body giant cells (FBGCs) were found associated with a connective tissue foreign body reaction resulting in fibrous encapsulation and/or material rejection. Despite the great majority of bone grafting materials routinely found with large osteoclasts, a special subclass of bone biomaterials has more recently been found surrounded by large giant cells virtually incapable of resorbing bone grafts even years after their implantation. While original hypotheses believed that a 'foreign body reaction' may be taking place, histological data retrieved from human samples years after their implantation have put these original hypotheses into question by demonstrating better and more stable long-term bone volume around certain bone grafts. Exactly how or why this 'special' subclass of giant cells is capable of maintaining long-term bone volume, or methods to scientifically distinguish them from osteoclasts remains extremely poorly studied. The aim of this review article was to gather the current available literature on giant cell markers and differences in expression patterns between osteoclasts and MNGCs utilizing 19 specific markers including an array of CD-cell surface markers. Furthermore, the concept of now distinguishing between pro-inflammatory M1-MNGCs (previously referred to as FBGCs) as well as wound-healing M2-MNGCs is introduced and discussed. This review article presents 19 specific cell-surface markers to distinguish between osteoclasts and MNGCs including an array of CD-cell surface markers. Furthermore, the concept of now distinguishing between pro-inflammatory M1-MNGCs (often previously referred to as FBGCs) as well as wound-healing M2-MNGCs is introduced and discussed. The proposed concepts and guidelines aims to guide the next wave of research facilitating the differentiation between osteoclast/MNGCs formation, as well as provides the basis for increasing our understanding of the exact function of MNGCs in bone tissue/biomaterial homeostasis. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A composite demineralized bone matrix--self assembling peptide scaffold for enhancing cell and growth factor activity in bone marrow.

PubMed

Hou, Tianyong; Li, Zhiqiang; Luo, Fei; Xie, Zhao; Wu, Xuehui; Xing, Junchao; Dong, Shiwu; Xu, Jianzhong

2014-07-01

The need for suitable bone grafts is high; however, there are limitations to all current graft sources, such as limited availability, the invasive harvest procedure, insufficient osteoinductive properties, poor biocompatibility, ethical problems, and degradation properties. The lack of osteoinductive properties is a common problem. As an allogenic bone graft, demineralized bone matrix (DBM) can overcome issues such as limited sources and comorbidities caused by invasive harvest; however, DBM is not sufficiently osteoinductive. Bone marrow has been known to magnify osteoinductive components for bone reconstruction because it contains osteogenic cells and factors. Mesenchymal stem cells (MSCs) derived from bone marrow are the gold standard for cell seeding in tissue-engineered biomaterials for bone repair, and these cells have demonstrated beneficial effects. However, the associated high cost and the complicated procedures limit the use of tissue-engineered bone constructs. To easily enrich more osteogenic cells and factors to DBM by selective cell retention technology, DBM is modified by a nanoscale self-assembling peptide (SAP) to form a composite DBM/SAP scaffold. By decreasing the pore size and increasing the charge interaction, DBM/SAP scaffolds possess a much higher enriching yield for osteogenic cells and factors compared with DBM alone scaffolds. At the same time, SAP can build a cellular microenvironment for cell adhesion, proliferation, and differentiation that promotes bone reconstruction. As a result, a suitable bone graft fabricated by DBM/SAP scaffolds and bone marrow represents a new strategy and product for bone transplantation in the clinic. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surface-mediated delivery of siRNA from fibrin hydrogels for knockdown of the BMP-2 binding antagonist noggin.

PubMed

Kowalczewski, Christine J; Saul, Justin M

2015-10-01

Antagonists and inhibitory molecules responsible for maintaining tissue homeostasis can present a significant barrier to healing when tissue engineering/regenerative medicine strategies are employed. One example of this situation is the up-regulation of antagonists such as noggin in response to increasing concentrations of bone morphogenetic protein-2 (BMP-2) present from endogenous bone repair processes or delivered exogenously from biomaterials (synthetic bone grafts). While recombinant human (rh)BMP-2 delivered from synthetic bone grafts has been shown to be an effective alternative to autografts and allografts, the supraphysiological doses of rhBMP-2 have led to clinically-adverse side effects. The high rhBMP-2 dosage may be required, in part, to overcome the presence of antagonists such as noggin. Small interfering RNA (siRNA) is an appealing approach to overcome this problem because it can knock-down antagonists or inhibitory molecules in a temporary manner. Here, we conducted fundamental studies on the delivery of siRNA from material surfaces as a means to knock-down antagonists like noggin. Non-viral cationic lipid (Lipofectamine)-siRNA complexes were delivered from a fibrin hydrogel surface to MC3T3-E1 preosteoblasts that were treated with a supraphysiological dose of rhBMP-2 to achieve noggin mRNA expression levels higher than cells naïve to rhBMP-2. Confocal microscopy and flow cytometry showed intracellular uptake of siRNA in over 98% of MC3T3-E1 cells after 48 h. Doses of 0.5 and 1 μg noggin siRNA were able to significantly reduce noggin mRNA to levels equivalent to those in MC3T3-E1 cells not exposed to rhBMP-2 with no effects on cell viability. Small interfering RNA (siRNA) has been considered for treatment of diseases ranging from Alzheimer's to cancer. However, the ability to use siRNA in conjunction with biomaterials to direct tissue regeneration processes has received relatively little attention. Using the bone morphogenetic protein 2 antagonist, noggin, as a model, this research describes an approach to knock-down molecules that are inhibitory to desired regenerative pathways at the mRNA level via siRNA delivery from a hydrogel surface. Interactions between the material (fibrin) surface and polycation-siRNA complexes, release of the siRNA from the material surface, high levels of cellular uptake/internalization of siRNA, and significant knockdown of the targeting (noggin) mRNA are demonstrated. Broader future applications include those to nerve regeneration, cardiovascular tissue engineering, directing (stem) cell behavior, and mitigating inflammatory responses to materials. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The use of a novel bone allograft wash process to generate a biocompatible, mechanically stable and osteoinductive biological scaffold for use in bone tissue engineering.

PubMed

Smith, C A; Richardson, S M; Eagle, M J; Rooney, P; Board, T; Hoyland, J A

2015-05-01

Fresh-frozen biological allograft remains the most effective substitute for the 'gold standard' autograft, sharing many of its osteogenic properties but, conversely, lacking viable osteogenic cells. Tissue engineering offers the opportunity to improve the osseointegration of this material through the addition of mesenchymal stem cells (MSCs). However, the presence of dead, immunogenic and potentially harmful bone marrow could hinder cell adhesion and differentiation, graft augmentation and incorporation, and wash procedures are therefore being utilized to remove the marrow, thereby improving the material's safety. To this end, we assessed the efficiency of a novel wash technique to produce a biocompatible, biological scaffold void of cellular material that was mechanically stable and had osteoinductive potential. The outcomes of our investigations demonstrated the efficient removal of marrow components (~99.6%), resulting in a biocompatible material with conserved biomechanical stability. Additionally, the scaffold was able to induce osteogenic differentiation of MSCs, with increases in osteogenic gene expression observed following extended culture. This study demonstrates the efficiency of the novel wash process and the potential of the resultant biological material to serve as a scaffold in bone allograft tissue engineering. © 2014 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons Ltd.

Paranuclear blue inclusions in metastatic undifferentiated small cell carcinoma in the bone marrow.

PubMed

Wittchow, R; Laszewski, M; Walker, W; Dick, F

1992-09-01

Paranuclear blue inclusions (PBIs) are frequently identified within metastatic undifferentiated small cell carcinoma (SCC) cells on air-dried bone marrow aspirates stained with Wright's stain. To determine the sensitivity and specificity of this finding, 116 bone marrow aspirates containing metastatic neoplasms were evaluated for the presence and frequency of PBIs. Bone marrow specimens included 47 cases of metastatic SCC of the lung, 13 cases of large cell lymphoma, 19 cases of neuroblastoma, five cases of small, noncleaved cell lymphoma, seven cases of rhabdomyosarcoma, three cases of Ewing's sarcoma, three cases of other sarcomas, and 19 cases of non-small cell carcinoma (adenocarcinoma). PBIs were identified in 40 of 47 (85%) cases of SCC and their frequency varied from 0 to 24% of tumor cells among different cases. In approximately half the cases of SCC, PBIs were identified in 1 to 4% tumor cells; and in eight cases, PBIs were present in 5% or more of tumor cells. PBIs were also identified in two of seven (29%) cases of rhabdomyosarcoma and one case of malignant peripheral nerve sheath tumor, but they were not seen in Ewing's sarcoma, small non-cleaved cell lymphoma, large cell lymphoma, neuroblastoma, or non-small cell carcinoma. In addition, PBIs were not seen in alcohol-fixed, Papanicolaou-stained cytology specimens containing SCC. Ultrastructurally, PBIs may represent phagocytized nuclear/cellular material. PBIs are a feature of small cell carcinoma on air-dried, cytologic material stained with Romanowsky type stains. Their presence may provide diagnostic information with regard to the differential diagnosis of metastatic SCC in the bone marrow. Future studies evaluating non-bone marrow Wright's stained fine-needle aspiration specimens are needed to determine if PBIs are useful in distinguishing SCC from other poorly differentiated tumors in the cytology laboratory.

Biomimetic nanoclay scaffolds for bone tissue engineering

NASA Astrophysics Data System (ADS)

Ambre, Avinash Harishchandra

Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was used for preparing composites (films and scaffolds) containing in situ HAPclay. Composite films showed significantly improved nanomechanical properties. Human MSCs formed mineralized ECM on films in absence of osteogenic supplements and were able to infiltrate the scaffolds. Atomic force microscopy imaging of mineralized ECM formed on composite films showed similarities in dimensions, arrangement of collagen and apatite with their natural bone counterparts. This work indicates the potential of in situ HAPclay to impart polymeric scaffolds with osteoinductive, osteoconductive abilities and improve their mechanical properties besides emphasizing nanoclays as cell-instructive materials.

Integrin-extracellular matrix interactions in connective tissue remodeling and osteoblast differentiation

NASA Technical Reports Server (NTRS)

Globus, R. K.; Moursi, A.; Zimmerman, D.; Lull, J.; Damsky, C.

1995-01-01

The differentiaton of bone cells is a complex multistep process. Bone is somewhat unusual in that it is very actively and continually remodeled in the adult and that maintenance of its mass in the mature organism is exquisitely sensitive to mechanical as well as chemical signals. Bone is also unique because it consists of a very large amount of extracellular matrix (ECM) that is mineralized. The integrin family of ECM receptors has been shown to play an important role in tissue morphogenesis in several systems. Our studies on the regulation of matrix remodeling enzymes by integrins in rabbit synovial fibroblasts show that two b1 integrin fibronectin (FN) receptor complexes (alpha 5 beta 1 and alpha 4 beta 1) cooperate in detecting subtle changes in the composition of the ECM. As a result of signal transduction by these integrins, the levels of mRNA and protein for several members of the metalloproteinase family are regulated in these cells. We have also used antibody and RGD peptide perturbation studies to determine the significance of cell/ECM interactions to normal osteogenesis. We found that interactions between the cell binding domain of FN and integrins are required for both normal morphogenesis and gene expression in cultured osteoblasts that differentiate to form bone-like tissue in culture. These data lead us to propose that beta 1 integrins play an important role in osteoblast differentiation as well as in bone remodeling.

Production of microscale particles from fish bone by gas flow assisted laser ablation

NASA Astrophysics Data System (ADS)

Boutinguiza, M.; Lusquiños, F.; Comesaña, R.; Riveiro, A.; Quintero, F.; Pou, J.

2007-12-01

Recycled wastes from fish and seafood can constitute a source of precursor material for different applications in the biomedical field such as bone fillers or precursor material for bioceramic coatings to improve the osteointegration of metallic implants. In this work, fish bones have been used directly as target in a laser ablation system. A pulsed Nd:YAG laser was used to ablate the fish bone material and a transverse air flow was used to extract the ablated material out of the interaction zone. The particles collected at a filter were in the micro and nanoscale range. The morphology as well as the composition of the obtained particles were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The results reveal that the composition of the analyzed particles is similar to that of the inorganic part of the fish bone.

Hybrid micro/nano-topography of a TiO2 nanotube-coated commercial zirconia femoral knee implant promotes bone cell adhesion in vitro.

PubMed

Frandsen, Christine J; Noh, Kunbae; Brammer, Karla S; Johnston, Gary; Jin, Sungho

2013-07-01

Various approaches have been studied to engineer the implant surface to enhance bone in-growth properties, particularly using micro- and nano-topography. In this study, the behavior of osteoblast (bone) cells was analyzed in response to a titanium oxide (TiO2) nanotube-coated commercial zirconia femoral knee implant consisting of a combined surface structure of a micro-roughened surface with the nanotube coating. The osteoblast cells demonstrated high degrees of adhesion and integration into the surface of the nanotube-coated implant material, indicating preferential cell behavior on this surface when compared to the bare implant. The results of this brief study provide sufficient evidence to encourage future studies. The development of such hierarchical micro- and nano-topographical features, as demonstrated in this work, can provide insightful designs for advanced bone-inducing material coatings on ceramic orthopedic implant surfaces. Copyright © 2013 Elsevier B.V. All rights reserved.

[Development, physiology, and cell activity of bone].

PubMed

de Baat, P; Heijboer, M P; de Baat, C

2005-07-01

Bones are of crucial importance for the human body, providing skeletal support, serving as a home for the formation of haematopoietic cells, and reservoiring calcium and phosphate. Long bones develop by endochondral ossification. Flat bones develop by intramembranous ossification. Bone tissue contains hydroxyapatite and various extracellular proteins, producing bone matrix. Two biological mechanisms, determining the strength of bone, are modelling and remodelling. Modelling can change bone shape and size through bone formation by osteoblasts at some sites and through bone destruction by osteoclasts at other sites. Remodelling is bone turnover, also performed by osteoclasts and osteoblasts. The processes of modelling and remodelling are induced by mechanical loads, predominantly muscle loads. Osteoblasts develop from mesenchymal stem cells. Many stimulating factors are known to activate the differentiation. Mature osteoblasts synthesize bone matrix and may further differentiate into osteocytes. Osteocytes maintain structural bone integrity and allow bone to adapt to any mechanical and chemical stimulus. Osteoclasts derive from haematopoietic stem cells. A number of transcription and growth factors have been identified essential for osteoclast differentiation and function. Finally, there is a complex interaction between osteoblasts and osteoclasts. Bone destruction starts by attachment of osteoclasts to the bone surface. Following this, osteoclasts undergo specific morphological changes. The process of bone destruction starts by acid dissolution of hydroxyapatite. After that osteoclasts start to destruct the organic matrix.

Galectin-3 as a novel regulator of osteoblast-osteoclast interaction and bone homeostasis.

PubMed

Simon, Dominic; Derer, Anja; Andes, Fabian T; Lezuo, Patrick; Bozec, Aline; Schett, Georg; Herrmann, Martin; Harre, Ulrike

2017-12-01

Bone tissue undergoes permanent and lifelong remodeling with a concerted action of bone-building osteoblasts and bone-resorbing osteoclasts. A precise cooperation between those two cell types is critical in the complex process of bone renewal. Galectin-3 is a member of the β-galactoside-binding lectin family playing multiple roles in cell growth, differentiation and aggregation. As it has been described to be expressed in bone, galectin-3 might influence bone homeostasis by regulating the function and/or interplay of osteoblasts and osteoclasts. Here, we investigated the role of galectin-3 in osteoclastogenesis and osteoblast-osteoclast interactions. Bone histomorphometric analysis and μCT measurements revealed a decreased trabecular bone volume and an increased osteoclast number in 12weeks old male galectin-3 knockout mice compared to wildtype littermates. Galectin-3 deficient bone marrow cells displayed a higher osteoclastogenic capacity in ex vivo differentiation assays, associated with elevated TRAF6 mRNA levels, suggesting an intrinsic inhibition of osteoclastogenesis by galectin-3 interfering with RANKL-mediated signaling. Furthermore, the addition of extracellular galectin-3 to murine or human osteoclastogenesis assays inhibited osteoclast formation and osteoclast numbers were higher in co-culture assays with galectin-3 deficient osteoblasts. In conclusion, our data suggest the secretion of galectin-3 as a novel mechanism for osteoblasts to control osteoclastogenesis and to maintain trabecular bone homeostasis independently of the RANKL/OPG-axis. Copyright © 2017 Elsevier Inc. All rights reserved.

Injectable calcium sulfate/mineralized collagen-based bone repair materials with regulable self-setting properties.

PubMed

Chen, Zonggang; Liu, Huanye; Liu, Xi; Cui, Fu-Zhai

2011-12-15

An injectable and self-setting bone repair materials (nano-hydroxyapatite/collagen/calcium sulfate hemihydrate, nHAC/CSH) was developed in this study. The nano-hydroxyapatite/collagen (nHAC) composite, which is the mineralized fibril by self-assembly of nano-hydrocyapatite and collagen, has the same features as natural bone in both main hierarchical microstructure and composition. It is a bioactive osteoconductor due to its high level of biocompatibility and appropriate degradation rate. However, this material lacks handling characteristics because of its particle or solid-preformed block shape. Herein, calcium sulfate hemihydrate (CSH) was introduced into nHAC to prepare an injectable and self-setting in situ bone repair materials. The morphology of materials was observed using SEM. Most important and interesting of all, calcium sulfate dihydrate (CSD), which is not only the reactant of preparing CSH but also the final solidified product of CSH, was introduced into nHAC as setting accelerator to regulate self-setting properties of injectable nHAC/CSH composite, and thus the self-setting time of nHAC/CSH composite can be regulated from more than 100 min to about 30 min and even less than 20 min by adding various amount of setting accelerator. The compressive properties of bone graft substitute after final setting are similar to those of cancellous bone. CSD as an excellent setting accelerator has no significant effect on the mechanical property and degradability of bone repair materials. In vitro biocompatibility and in vivo histology studies demonstrated that the nHAC/CSH composite could provide more adequate stimulus for cell adhesion and proliferation, embodying favorable cell biocompatibility and a strong ability to accelerate bone formation. It can offer a satisfactory biological environment for growing new bone in the implants and for stimulating bone formation. Copyright © 2011 Wiley Periodicals, Inc.

3D Powder Printed Bioglass and β-Tricalcium Phosphate Bone Scaffolds.

PubMed

Seidenstuecker, Michael; Kerr, Laura; Bernstein, Anke; Mayr, Hermann O; Suedkamp, Norbert P; Gadow, Rainer; Krieg, Peter; Hernandez Latorre, Sergio; Thomann, Ralf; Syrowatka, Frank; Esslinger, Steffen

2017-12-22

The use of both bioglass (BG) and β tricalcium phosphate (β-TCP) for bone replacement applications has been studied extensively due to the materials' high biocompatibility and ability to resorb when implanted in the body. 3D printing has been explored as a fast and versatile technique for the fabrication of porous bone scaffolds. This project investigates the effects of using different combinations of a composite BG and β-TCP powder for 3D printing of porous bone scaffolds. Porous 3D powder printed bone scaffolds of BG, β-TCP, 50/50 BG/β-TCP and 70/30 BG/β-TCP compositions were subject to a variety of characterization and biocompatibility tests. The porosity characteristics, surface roughness, mechanical strength, viability for cell proliferation, material cytotoxicity and in vitro bioactivity were assessed. The results show that the scaffolds can support osteoblast-like MG-63 cells growth both on the surface of and within the scaffold material and do not show alarming cytotoxicity; the porosity and surface characteristics of the scaffolds are appropriate. Of the two tested composite materials, the 70/30 BG/β-TCP scaffold proved to be superior in terms of biocompatibility and mechanical strength. The mechanical strength of the scaffolds makes them unsuitable for load bearing applications. However, they can be useful for other applications such as bone fillers.

Effect of bone sialoprotein coating of ceramic and synthetic polymer materials on in vitro osteogenic cell differentiation and in vivo bone formation.

PubMed

Schaeren, Stefan; Jaquiéry, Claude; Wolf, Francine; Papadimitropoulos, Adam; Barbero, Andrea; Schultz-Thater, Elke; Heberer, Michael; Martin, Ivan

2010-03-15

In this study, we addressed whether Bone Sialoprotein (BSP) coating of various substrates could enhance the in vitro osteogenic differentiation and in vivo bone formation capacity of human Bone Marrow Stromal Cells (BMSC). Moreover, we tested whether synthetic polymer-based porous scaffolds, despite the absence of a mineral component, could support ectopic bone formation by human BMSC if coated with BSP. Adsorption of recombinant human BSP on tissue culture-treated polystyrene (TCTP), beta-tricalcium phosphate (Osteologic) or synthetic polymer (Polyactive) substrates was dose dependent, but did not consistently accelerate or enhance in vitro BMSC osteogenic differentiation, as assessed by the mRNA expression of osteoblast-related genes. Similarly, BSP coating of porous beta-tricalcium phosphate scaffolds (Skelite) did not improve the efficiency of bone tissue formation following loading with BMSC and ectopic implantation in nude mice. Finally, Polyactive foams seeded with BMSC did not form bone tissue in the same ectopic assay, even if coated with BSP. We conclude that BSP coating of a variety of substrates is not directly associated with an enhancement of osteoprogenitor cell differentiation in vitro or in vivo, and that presentation of BSP on polymeric materials is not sufficient to prime BMSC functional osteoblastic differentiation in vivo. (c) 2009 Wiley Periodicals, Inc.

On the representation of cells in bone marrow pathology by a scalar field: propagation through serial sections, co-localization and spatial interaction analysis.

PubMed

Weis, Cleo-Aron; Grießmann, Benedict Walter; Scharff, Christoph; Detzner, Caecilia; Pfister, Eva; Marx, Alexander; Zoellner, Frank Gerrit

2015-09-02

Immunohistochemical analysis of cellular interactions in the bone marrow in situ is demanding, due to its heterogeneous cellular composition, the poor delineation and overlap of functional compartments and highly complex immunophenotypes of several cell populations (e.g. regulatory T-cells) that require immunohistochemical marker sets for unambiguous characterization. To overcome these difficulties, we herein present an approach to describe objects (e.g. cells, bone trabeculae) by a scalar field that can be propagated through registered images of serial histological sections. The transformation of objects within images (e.g. cells) to a scalar field was performed by convolution of the object's centroids with differently formed radial basis function (e.g. for direct or indirect spatial interaction). On the basis of such a scalar field, a summation field described distributed objects within an image. After image registration i) colocalization analysis could be performed on basis scalar field, which is propagated through registered images, and - due to the shape of the field - were barely prone to matching errors and morphological changes by different cutting levels; ii) furthermore, depending on the field shape the colocalization measurements could also quantify spatial interaction (e.g. direct or paracrine cellular contact); ii) the field-overlap, which represents the spatial distance, of different objects (e.g. two cells) could be calculated by the histogram intersection. The description of objects (e.g. cells, cell clusters, bone trabeculae etc.) as a field offers several possibilities: First, co-localization of different markers (e.g. by immunohistochemical staining) in serial sections can be performed in an automatic, objective and quantifiable way. In contrast to multicolour staining (e.g. 10-colour immunofluorescence) the financial and technical requirements are fairly minor. Second, the approach allows searching for different types of spatial interactions (e.g. direct and indirect cellular interaction) between objects by taking field shape into account (e.g. thin vs. broad). Third, by describing spatially distributed groups of objects as summation field, it gives cluster definition that relies rather on the bare object distance than on the modelled spatial cellular interaction.

Mechanical degradation of TiO2 nanotubes with and without nanoparticulate silver coating

PubMed Central

Shivaram, Anish; Bose, Susmita; Bandyopadhyay, Amit

2016-01-01

The primary objective of this research was to evaluate the extent of mechanical degradation on TiO2 nanotubes on Ti with and without nano-particulate silver coating using two different lengths of TiO2 nanotubes- 300nm and ~ 1µm, which were fabricated on commercially pure Titanium (cp-Ti) rods using anodization method using two different electrolytic mediums - (1) deionized (DI) water with 1% HF, and (2) ethylene glycol with 1% HF, 0.5 wt%. NH4F and 10% DI water. Nanotubes fabricated rods were implanted into equine cadaver bone to evaluate mechanical damage at the surface. Silver was electrochemically deposited on these nanotubes and using a release study, silver ion concentrations were measured before and after implantation, followed by surface characterization using a Field Emission Scanning Electron Microscope (FESEM). In vitro cell-material interaction study was performed using human fetal osteoblast cells (hFOB) to understand the effect of silver coating using an MTT assay for proliferation and to determine any cytotoxic effect on the cells and to study its biocompatibility. No significant damage due to implantation was observed for nanotubes up to ~1 µm length under current experimental conditions. Cell-materials interaction showed no cytotoxic effects on the cells due to silver coating and anodization of samples. PMID:27017285

Osthole inhibits bone metastasis of breast cancer

PubMed Central

Guo, Baofeng; Ye, Yiyi; Han, Xianghui; Qin, Yuenong; Liu, Sheng

2017-01-01

Bone is one of the most common sites for breast cancer metastasis, which greatly contributes to patient morbidity and mortality. Osthole, a major extract from Cnidium monnieri (L.), exhibits many biological and pharmacological activities, however, its potential as a therapeutic agent in the treatment of breast cancer bone metastases remain poorly understood. In this study, we set out to investigate whether osthole could inhibit breast cancer metastasis to bone in mice and clarified the potential mechanism of this inhibition. In the murine model of breast cancer osseous metastasis, mice that received osthole developed significantly less bone metastases and displayed decreased tumor burden when compared with mice in the control group. Osthole inhibited breast cancer cell growth, migration, and invasion, and induced apoptosis of breast cancer cells. Additionally, it also regulated OPG/RANKL signals in the interactions between bone cells (osteoblasts and osteoclasts) and cancer cells. Besides, it also inhibited TGF-β/Smads signaling in breast cancer metastasis to bone in MDA-231BO cells. The results of this study suggest that osthole has real potential as a therapeutic candidate in the treatment of breast cancer patients with bone metastases. PMID:28938572

Graphene-Oxide-Decorated Microporous Polyetheretherketone with Superior Antibacterial Capability and In Vitro Osteogenesis for Orthopedic Implant.

PubMed

Ouyang, Ling; Deng, Yi; Yang, Lei; Shi, Xiuyuan; Dong, Taosheng; Tai, Youyi; Yang, Weizhong; Chen, Zhi-Gang

2018-05-02

Due to its similar elastic modulus of human bones, polyetheretherketone (PEEK) has been considered as an excellent cytocompatible material. However, the bioinertness, poor osteoconduction, and weak antibacterial activity of PEEK limit its wide applications in clinics. In this study, a facile strategy is developed to prepare graphene oxide (GO) modified sulfonated polyetheretherketone (SPEEK) (GO-SPEEK) through a simple dip-coating method. After detailed characterization, it is found that the GO closely deposits on the surface of PEEK, which is attributed to the π-π stacking interaction between PEEK and GO. Antibacterial tests reveal that the GO-SPEEK exhibits excellent suppression toward Escherichia coli. In vitro cell attachment, growth, differentiation, alkaline phosphatase activity, quantitative real-time polymerase chain reaction analyses, and calcium mineral deposition all illustrate that the GO-SPEEK substrate can significantly accelerate the proliferation and osteogenic differentiation of osteoblast-like MG-63 cells compared with those on PEEK and SPEEK groups. These results suggest that the GO-SPEEK has an improved antibacterial activity and cytocompatibility in vitro, showing that the developed GO-SPEEK has a great potential as the bioactive implant material in bone tissue engineering. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Decellularized cartilage-derived matrix as substrate for endochondral bone regeneration.

PubMed

Gawlitta, Debby; Benders, Kim E M; Visser, Jetze; van der Sar, Anja S; Kempen, Diederik H R; Theyse, Lars F H; Malda, Jos; Dhert, Wouter J A

2015-02-01

Following an endochondral approach to bone regeneration, multipotent stromal cells (MSCs) can be cultured on a scaffold to create a cartilaginous callus that is subsequently remodeled into bone. An attractive scaffold material for cartilage regeneration that has recently regained attention is decellularized cartilage-derived matrix (CDM). Since this material has shown potential for cartilage regeneration, we hypothesized that CDM could be a potent material for endochondral bone regeneration. In addition, since decellularized matrices are known to harbor bioactive cues for tissue formation, we evaluated the need for seeded MSCs in CDM scaffolds. In this study, ectopic bone formation in rats was evaluated for CDM scaffolds seeded with human MSCs and compared with unseeded controls. The MSC-seeded samples were preconditioned in chondrogenic medium for 37 days. After 8 weeks of subcutaneous implantation, the extent of mineralization was significantly higher in the MSC-seeded constructs versus unseeded controls. The mineralized areas corresponded to bone formation with bone marrow cavities. In addition, rat-specific bone formation was confirmed by collagen type I immunohistochemistry. Finally, fluorochrome incorporation at 3 and 6 weeks revealed that the bone formation had an inwardly directed progression. Taken together, our results show that decellularized CDM is a promising biomaterial for endochondral bone regeneration when combined with MSCs at ectopic locations. Modification of current decellularization protocols may lead to enhanced functionality of CDM scaffolds, potentially offering the prospect of generation of cell-free off-the-shelf bone regenerative substitutes.

Osteoconductive Amine-Functionalized Graphene-Poly(methyl methacrylate) Bone Cement Composite with Controlled Exothermic Polymerization.

PubMed

Sharma, Rakesh; Kapusetti, Govinda; Bhong, Sayali Yashwant; Roy, Partha; Singh, Santosh Kumar; Singh, Shikha; Balavigneswaran, Chelladurai Karthikeyan; Mahato, Kaushal Kumar; Ray, Biswajit; Maiti, Pralay; Misra, Nira

2017-09-20

Bone cement has found extensive usage in joint arthroplasty over the last 50 years; still, the development of bone cement with essential properties such as high fatigue resistance, lower exothermic temperature, and bioactivity has been an unsolved problem. In our present work, we have addressed all of the mentioned shortcomings of bone cement by reinforcing it with graphene (GR), graphene oxide (GO), and surface-modified amino graphene (AG) fillers. These nanocomposites have shown hypsochromic shifts, suggesting strong interactions between the filler material and the polymer matrix. AG-based nanohybrids have shown greater osteointegration and lower cytotoxicity compared to other nanohybrids as well as pristine bone cement. They have also reduced oxidative stress on cells, resulting in calcification within 20 days of the implantation of nanohybrids into the rabbits. They have significantly reduced the exothermic curing temperature to body temperature and increased the setting time to facilitate practitioners, suggesting that reaction temperature and settling time can be dynamically controlled by varying the concentration of the filler. Thermal stability and enhanced mechanical properties have been achieved in nanohybrids vis-à-vis pure bone cement. Thus, this newly developed nanocomposite can create natural bonding with bone tissues for improved bioactivity, longer sustainability, and better strength in the prosthesis.

Glyoxal Crosslinking of Cell-Seeded Chitosan/Collagen Hydrogels for Bone Regeneration

PubMed Central

Wang, Limin; Stegemann, Jan P.

2011-01-01

Chitosan and collagen are natural biomaterials that have been used extensively in tissue engineering, both separately and as composite materials. Most methods to fabricate chitosan/collagen composites use freeze drying and chemical crosslinking to create stable porous scaffolds, which subsequently can be seeded with cells. In this study, we directly embedded human bone marrow stem cells (hBMSC) in chitosan/collagen materials by initiating gelation using β-glycerophosphate at physiological temperature and pH. We further examined the use of glyoxal, a dialdehyde with relatively low toxicity, to crosslink these materials and characterized the resulting changes in matrix and cell properties. The cytocompatibility of glyoxal and the crosslinked gels were investigated in terms of hBMSC metabolic activity, viability, proliferation, and osteogenic differentiation. These studies revealed that glyoxal was cytocompatible at concentrations below about 1 mM for periods of exposure up to 15 h, though the degree of cell spreading and proliferation were dependent on matrix composition. Glyoxal-crosslinked matrices were stiffer and compacted less than uncrosslinked controls. It was further demonstrated that hBMSC can attach and proliferate in 3D matrices composed of 50/50 chitosan/collagen, and that these materials supported osteogenic differentiation in response to stimulation. Such glyoxal-crosslinked chitosan/collagen composite materials may find utility as cell delivery vehicles for enhancing the repair of bone defects. PMID:21345389

Bioactive nanoparticle-gelatin composite scaffold with mechanical performance comparable to cancellous bones.

PubMed

Wang, Chen; Shen, Hong; Tian, Ye; Xie, Yue; Li, Ailing; Ji, Lijun; Niu, Zhongwei; Wu, Decheng; Qiu, Dong

2014-08-13

Mechanical properties are among the most concerned issues for artificial bone grafting materials. The scaffolds used for bone grafts are either too brittle (glass) or too weak (polymer), and therefore composite scaffolds are naturally expected as the solution. However, despite the intensive studies on composite bone grafting materials, there still lacks a material that could be matched to the natural cancellous bones. In this study, nanosized bioactive particles (BP) with controllable size and good colloidal stability were used to composite with gelatin, forming macroporous scaffolds. It was found that the mechanical properties of obtained composite scaffolds, in terms of elastic modulus, compressive strength, and strain at failure, could match to that of natural cancellous bones. This is ascribed to the good distribution of particle in matrix and strong interaction between particle and gelatin. Furthermore, the incorporation of BPs endues the composite scaffolds with bioactivity, forming HA upon reacting with simulated body fluid (SBF) within days, thus stimulating preosteoblasts attachment, growth, and proliferation in these scaffolds. Together with their good mechanical properties, these composite scaffolds are promising artificial bone grating materials.

Muscle-bone Interactions During Fracture Healing

DTIC Science & Technology

2015-03-01

stem cells (MSCs). The in- flammatory cells release cytokines such as TNF-α, IL-1, IL- 6, IL-11, and IL-18 to induce osteogenic differentiation of MSCs...Bone, Fracture, Mesenchymal Stem Cells , Paracrine Review Article Hylonome The authors have no conflict of interest. Corresponding author: Melissa...1992;(275):280-6. 16. Mills SJ, Cowin AJ, Kaur P. Pericytes, mesenchymal stem cells and the wound healing process. Cells 2013;2:621-34. 17. Kumar A

Comparison of in vitro biocompatibility of NanoBone(®) and BioOss(®) for human osteoblasts.

PubMed

Liu, Qin; Douglas, Timothy; Zamponi, Christiane; Becker, Stephan T; Sherry, Eugene; Sivananthan, Sureshan; Warnke, Frauke; Wiltfang, Jörg; Warnke, Patrick H

2011-11-01

Scaffolds for bone tissue engineering seeded with the patient's own cells might be used as a preferable method to repair bone defects in the future. With the emerging new technologies of nanostructure design, new synthetic biomaterials are appearing on the market. Such scaffolds must be tested in vitro for their biocompatibility before clinical application. However, the choice between a natural or a synthetic biomaterial might be challenging for the doctor and the patient. In this study, we compared the biocompatibility of a synthetic bone substitute, NanoBone(®) , to the widely used natural bovine bone replacement material BioOss(®) . The in vitro behaviour of human osteoblasts on both materials was investigated. Cell performance was determined using scanning electron microscopy (SEM), cell vitality staining and four biocompatibility tests (LDH, MTT, WST, BrdU). We found that both materials showed low cytotoxicity and good biocompatibility. The MTT proliferation test was superior for Nanobone(®) . Both scaffolds caused only little damage to human osteoblasts and justify their clinical application. However, NanoBone(®) was able to support and promote proliferation of human osteoblasts slightly better than BioOss(®) in our chosen test set-up. The results may guide doctors and patients when being challenged with the choice between a natural or a synthetic biomaterial. Further experiments are necessary to determine the comparison of biocompatibility in vivo. © 2011 John Wiley & Sons A/S.

Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone.

PubMed

Ng, Angela M H; Tan, K K; Phang, M Y; Aziyati, O; Tan, G H; Isa, M R; Aminuddin, B S; Naseem, M; Fauziah, O; Ruszymah, B H I

2008-05-01

Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering. Copyright 2007 Wiley Periodicals, Inc.

Coculture strategies in bone tissue engineering: the impact of culture conditions on pluripotent stem cell populations.

PubMed

Janardhanan, Sathyanarayana; Wang, Martha O; Fisher, John P

2012-08-01

The use of pluripotent stem cell populations for bone tissue regeneration provides many opportunities and challenges within the bone tissue engineering field. For example, coculture strategies have been utilized to mimic embryological development of bone tissue, and particularly the critical intercellular signaling pathways. While research in bone biology over the last 20 years has expanded our understanding of these intercellular signaling pathways, we still do not fully understand the impact of the system's physical characteristics (orientation, geometry, and morphology). This review of coculture literature delineates the various forms of coculture systems and their respective outcomes when applied to bone tissue engineering. To understand fully the key differences between the different coculture methods, we must appreciate the underlying paradigms of physiological interactions. Recent advances have enabled us to extrapolate these techniques to larger dimensions and higher geometric resolutions. Finally, the contributions of bioreactors, micropatterned biomaterials, and biomaterial interaction platforms are evaluated to give a sense of the sophistication established by a combination of these concepts with coculture systems.

Characterization of the bone marrow adipocyte niche with three-dimensional electron microscopy.

PubMed

Robles, Hero; Park, SungJae; Joens, Matthew S; Fitzpatrick, James A J; Craft, Clarissa S; Scheller, Erica L

2018-01-27

Unlike white and brown adipose tissues, the bone marrow adipocyte (BMA) exists in a microenvironment containing unique populations of hematopoietic and skeletal cells. To study this microenvironment at the sub-cellular level, we performed a three-dimensional analysis of the ultrastructure of the BMA niche with focused ion beam scanning electron microscopy (FIB-SEM). This revealed that BMAs display hallmarks of metabolically active cells including polarized lipid deposits, a dense mitochondrial network, and areas of endoplasmic reticulum. The distinct orientations of the triacylglycerol droplets suggest that fatty acids are taken up and/or released in three key areas - at the endothelial interface, into the hematopoietic milieu, and at the bone surface. Near the sinusoidal vasculature, endothelial cells send finger-like projections into the surface of the BMA which terminate near regions of lipid within the BMA cytoplasm. In some regions, perivascular cells encase the BMA with their flattened cellular projections, limiting contacts with other cells in the niche. In the hematopoietic milieu, BMAT adipocytes of the proximal tibia interact extensively with maturing cells of the myeloid/granulocyte lineage. Associations with erythroblast islands are also prominent. At the bone surface, the BMA extends organelle and lipid-rich cytoplasmic regions toward areas of active osteoblasts. This suggests that the BMA may serve to partition nutrient utilization between diverse cellular compartments, serving as an energy-rich hub of the stromal-reticular network. Lastly, though immuno-EM, we've identified a subset of bone marrow adipocytes that are innervated by the sympathetic nervous system, providing an additional mechanism for regulation of the BMA. In summary, this work reveals that the bone marrow adipocyte is a dynamic cell with substantial capacity for interactions with the diverse components of its surrounding microenvironment. These local interactions likely contribute to its unique regulation relative to peripheral adipose tissues. Copyright © 2018 Elsevier Inc. All rights reserved.

Mechanical Regulation of Signaling Pathways in Bone

PubMed Central

Thompson, William R.; Rubin, Clinton T.; Rubin, Janet

2012-01-01

A wide range of cell types depend on mechanically induced signals to enable appropriate physiological responses. The skeleton is particularly dependent on mechanical information to guide the resident cell population towards adaptation, maintenance and repair. Research at the organ, tissue, cell and molecular levels has improved our understanding of how the skeleton can recognize the functional environment, and how these challenges are translated into cellular information that can site-specifically alter phenotype. This review first considers those cells within the skeleton that are responsive to mechanical signals, including osteoblasts, osteoclasts, osteocytes and osteoprogenitors. This is discussed in light of a range of experimental approaches that can vary parameters such as strain, fluid shear stress, and pressure. The identity of mechanoreceptor candidates is approached, with consideration of integrins, pericellular tethers, focal adhesions, ion channels, cadherins, connexins, and the plasma membrane including caveolar and non-caveolar lipid rafts and their influence on integral signaling protein interactions. Several mechanically regulated intracellular signaling cascades are detailed including activation of kinases (Akt, MAPK, FAK), β-catenin, GTPases, and calcium signaling events. While the interaction of bone cells with their mechanical environment is complex, an understanding of mechanical regulation of bone signaling is crucial to understanding bone physiology, the etiology of diseases such as osteoporosis, and to the development of interventions to improve bone strength. PMID:22575727

Strategies for cell manipulation and skeletal tissue engineering using high-throughput polymer blend formulation and microarray techniques.

PubMed

Khan, Ferdous; Tare, Rahul S; Kanczler, Janos M; Oreffo, Richard O C; Bradley, Mark

2010-03-01

A combination of high-throughput material formulation and microarray techniques were synergistically applied for the efficient analysis of the biological functionality of 135 binary polymer blends. This allowed the identification of cell-compatible biopolymers permissive for human skeletal stem cell growth in both in vitro and in vivo applications. The blended polymeric materials were developed from commercially available, inexpensive and well characterised biodegradable polymers, which on their own lacked both the structural requirements of a scaffold material and, critically, the ability to facilitate cell growth. Blends identified here proved excellent templates for cell attachment, and in addition, a number of blends displayed remarkable bone-like architecture and facilitated bone regeneration by providing 3D biomimetic scaffolds for skeletal cell growth and osteogenic differentiation. This study demonstrates a unique strategy to generate and identify innovative materials with widespread application in cell biology as well as offering a new reparative platform strategy applicable to skeletal tissues. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Autologous serum improves bone formation in a primary stable silica-embedded nanohydroxyapatite bone substitute in combination with mesenchymal stem cells and rhBMP-2 in the sheep model

PubMed Central

Boos, Anja M; Weigand, Annika; Deschler, Gloria; Gerber, Thomas; Arkudas, Andreas; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P

2014-01-01

New therapeutic strategies are required for critical size bone defects, because the gold standard of transplanting autologous bone from an unharmed area of the body often leads to several severe side effects and disadvantages for the patient. For years, tissue engineering approaches have been seeking a stable, axially vascularized transplantable bone replacement suitable for transplantation into the recipient bed with pre-existing insufficient conditions. For this reason, the arteriovenous loop model was developed and various bone substitutes have been vascularized. However, it has not been possible thus far to engineer a primary stable and axially vascularized transplantable bone substitute. For that purpose, a primary stable silica-embedded nanohydroxyapatite (HA) bone substitute in combination with blood, bone marrow, expanded, or directly retransplanted mesenchymal stem cells, recombinant human bone morphogenetic protein 2 (rhBMP-2), and different carrier materials (fibrin, cell culture medium, autologous serum) was tested subcutaneously for 4 or 12 weeks in the sheep model. Autologous serum lead to an early matrix change during degradation of the bone substitute and formation of new bone tissue. The best results were achieved in the group combining mesenchymal stem cells expanded with 60 μg/mL rhBMP-2 in autologous serum. Better ingrowth of fibrovascular tissue could be detected in the autologous serum group compared with the control (fibrin). Osteoclastic activity indicating an active bone remodeling process was observed after 4 weeks, particularly in the group with autologous serum and after 12 weeks in every experimental group. This study clearly demonstrates the positive effects of autologous serum in combination with mesenchymal stem cells and rhBMP-2 on bone formation in a primary stable silica-embedded nano-HA bone grafting material in the sheep model. In further experiments, the results will be transferred to the sheep arteriovenous loop model in order to engineer an axially vascularized primary stable bone replacement in clinically relevant size for free transplantation. PMID:25429218

The effect of cationically-modified phosphorylcholine polymers on human osteoblasts in vitro and their effect on bone formation in vivo.

PubMed

Lawton, Jonathan M; Habib, Mariam; Ma, Bingkui; Brooks, Roger A; Best, Serena M; Lewis, Andrew L; Rushton, Neil; Bonfield, William

2017-08-17

The effect of introducing cationic charge into phosphorylcholine (PC)-based polymers has been investigated in this study with a view to using these materials as coatings to improve bone formation and osseointegration at the bone-implant interface. PC-based polymers, which have been used in a variety of medical devices to improve biocompatibility, are associated with low protein adsorption resulting in reduced complement activation, inflammatory response and cell adhesion. However, in some applications, such as orthopaedics, good integration between the implant and bone is needed to allow the distribution of loading stresses and a bioactive response is required. It has previously been shown that the incorporation of cationic charge into PC-based polymers may increase protein adsorption that stimulates subsequent cell adhesion. In this paper, the effect of cationic charge in PC-based polymers on human osteoblasts (HObs) in vitro and the effect of these polymers on bone formation in the rat tibia was assessed. Increasing PC positive surface charge increased HOb cell adhesion and stimulated increased cell differentiation and the production of calcium phosphate deposits. However, when implanted in bone these materials were at best biotolerant, stimulating the production of fibrous tissue and areas of loosely associated matrix (LAM) around the implant. Their development, as formulated in this study, as bone interfacing implant coatings is therefore not warranted.

Conception on the cell mechanisms of bone tissue loss under spase flight conditions

NASA Astrophysics Data System (ADS)

Rodionova, Natalia; Oganov, Victor; Kabitskaya, Olga

Basing on the analysis of available literature and the results of our own electron microscopic and radioautographic researches the data are presented about the morpho-functional peculiarities and succession of cellular interactions in adaptive remodeling of bone structures under normal conditions and after exposure of animals (rats, monkeys, mice) to microgravity (SLS-2, Bion-11, BionM-1). The probable cellular mechanisms of the development of osteopenia and osteoporosis are considered. Our conception on remodeling proposes the following sequence in the development of cellular interactions after decrease of the mechanical loading: a primary response of osteocytes (mechanosensory cells) to the mechanical stimulus; osteocytic remodeling (osteolysis); transmission of the mechanical signals through a system of canals and processes to functionally active osteoblasts and surface osteocytes as well as to the bone-marrow stromal cells and to those lying on bone surfaces. As a response to the mechanical stimulus (microgravity) the system of stromal cell-preosteoblast-osteoblast shows a delay in proliferation, differentiation and specific functioning of the osteogenetic cells, some of the osteoblasts undergo apoptosis. Then the osteoclastic reaction occurs (attraction of monocytes and formation of osteoclasts and bone matrix resorption in the loci of apoptosis of osteoblasts and osteocytes). The macrophagal reaction is followed by osteoblastogenesis, which appears to be a rehabilitating process. However, during prolonged absence of mechanical stimuli (microgravity, long-time immobilization) the adaptive activization of osteoblastogenesis doesn’t occur (as it is the case during the physiological remodeling of bone tissue) or it occurs to a smaller degree. The loading deficit leads to an adaptive differentiation of stromal cells to fibroblastic cells and adipocytes in these remodeling loci. These cell reactions are considered as adaptive-compensatory, but they don’t result in rehabilitation of the resorbed bone tissue. This sequence of events is considered as a mechanism of bone tissue loss which underlies the development of osteopenia and osteoporosis under the mechanical loading deficit.

Combined micro computed tomography and histology study of bone augmentation and distraction osteogenesis

NASA Astrophysics Data System (ADS)

Ilgenstein, Bernd; Deyhle, Hans; Jaquiery, Claude; Kunz, Christoph; Stalder, Anja; Stübinger, Stefan; Jundt, Gernot; Beckmann, Felix; Müller, Bert; Hieber, Simone E.

2012-10-01

Bone augmentation is a vital part of surgical interventions of the oral and maxillofacial area including dental implantology. Prior to implant placement, sufficient bone volume is needed to reduce the risk of peri-implantitis. While augmentation using harvested autologous bone is still considered as gold standard, many surgeons prefer bone substitutes to reduce operation time and to avoid donor site morbidity. To assess the osteogenic efficacy of commercially available augmentation materials we analyzed drill cores extracted before implant insertion. In younger patients, distraction osteogenesis is successfully applied to correct craniofacial deformities through targeted bone formation. To study the influence of mesenchymal stem cells on bone regeneration during distraction osteogenesis, human mesenchymal stem cells were injected into the distraction gap of nude rat mandibles immediately after osteotomy. The distraction was performed over eleven days to reach a distraction gap of 6 mm. Both the rat mandibles and the drill cores were scanned using synchrotron radiation-based micro computed tomography. The three-dimensional data were manually registered and compared with corresponding two-dimensional histological sections to assess bone regeneration and its morphology. The analysis of the rat mandibles indicates that bone formation is enhanced by mesenchymal stem cells injected before distraction. The bone substitutes yielded a wide range of bone volume and degree of resorption. The volume fraction of the newly formed bone was determined to 34.4% in the computed tomography dataset for the augmentation material Geistlich Bio-Oss®. The combination of computed tomography and histology allowed a complementary assessment for both bone augmentation and distraction osteogenesis.

Bone morphogenetic protein-mediated interaction of periosteum and diaphysis. Citric acid and other factors influencing the generation of parosteal bone.

PubMed

Kübler, N; Urist, M R

1990-09-01

In rabbits, after long-bone growth is complete and the cambium layer regresses, mesenchymal-type cells with embryonic potential (competence) for bone development persist in the adventitial layer of periosteum. These cells are not determined osteoprogenitor cells (stem cells) because bone tissue differentiation does not occur when adult periosteum is transplanted into a heterotopic site. In this respect, adventitial cells differ from bone marrow stroma cells. In a parosteal orthotopic site in the space between the adult periosteum and diaphysis, implants of bone morphogenetic protein (BMP) and associated noncollagenous proteins (BMP/NCP) induce adventitia and adjacent muscle connective-tissue-derived cells to switch from a fibrogenetic to a chondroosteoprogenetic pattern of bone development. The quantity of induced bone is proportional to the dose of BMP/NCP in the range from 10 to 50 mg; immature rabbits produced larger deposits than mature rabbits in response to BMP/NCP. Preoperative local intramuscular injections of citric, edetic, or hyaluronic acids in specified concentrations markedly enhanced subperiosteal BMP/NCP-induced bone formation. The quantity of bovine or human BMP/NCP-induced bone formation in rabbits is also increased by very low-dose immunosuppression but not by bone mineral, tricalcium phosphate ceramic, inorganic calcium salts, or various space-occupying, unspecific chemical irritants. Although composities of BMP/NCP and allogeneic rabbit tendon collagen increased the quantity of bone in a parosteal site, in a heterotopic site the composite failed to induce bone formation. In a parosteal site, the conditions permitting BMP/NCP-induced bone formation develop, and the end product of the morphogenetic response is a duplicate diaphysis. How BMP reactivates the morphogenetic process in postfetal mesenchymal-type adventitial cells persisting in adult periosteum (including adjacent muscle attachments) is not known.

Polyurethane foam/nano hydroxyapatite composite as a suitable scaffold for bone tissue regeneration.

PubMed

Meskinfam, M; Bertoldi, S; Albanese, N; Cerri, A; Tanzi, M C; Imani, R; Baheiraei, N; Farokhi, M; Farè, S

2018-01-01

In bone tissue regeneration, the use of biomineralized scaffolds to create the 3D porous structure needed for well-fitting with defect size and appropriate cell interactions, is a promising alternative to autologous and heterologous bone grafts. Biomineralized polyurethane (PU) foams are here investigated as scaffold for bone tissue regeneration. Biomineralization of the foams was carried out by activation of PU surface by a two steps procedure performed for different times (1 to 4 weeks). Scaffolds were investigated for morphological, chemico-physical and mechanical properties, as well as for in vitro interaction with rat Bone Marrow Mesenchymal Stem Cells (BMSCs). Untreated and biomineralized PU samples showed a homogenous morphology and regular pore size (average Ø=407μm). Phase and structure of formed calcium phosphates (CaPs) layer onto the PU foam were analyzed by Fourier Transform Infrared spectroscopy and X-ray diffraction, proving the formation of bone-like nano hydroxyapatite. Biomineralization caused a significant increase of mechanical properties of treated foams compared to untreated ones. Biomineralization also affected the PU scaffold cytocompatibility providing a more appropriate surface for cell attachment and proliferation. Considering the obtained results, the proposed scaffold can be considered suitable for bone tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

In vitro assessment of nanosilver-functionalized PMMA bone cement on primary human mesenchymal stem cells and osteoblasts.

PubMed

Pauksch, Linda; Hartmann, Sonja; Szalay, Gabor; Alt, Volker; Lips, Katrin S

2014-01-01

Peri-prosthetic infections caused by multidrug resistant bacteria have become a serious problem in surgery and orthopedics. The aim is to introduce biomaterials that avoid implant-related infections caused by multiresistant bacteria. The efficacy of silver nanoparticles (AgNP) against a broad spectrum of bacteria and against multiresistant pathogens has been repeatedly described. In the present study polymethylmethacrylate (PMMA) bone cement functionalized with AgNP and/or gentamicin were tested regarding their biocompatibility with bone forming cells. Therefore, influences on viability, cell number and differentiation of primary human mesenchymal stem cells (MSCs) and MSCs cultured in osteogenic differentiation media (MSC-OM) caused by the implant materials were studied. Furthermore, the growth behavior and the morphology of the cells on the testing material were observed. Finally, we examined the induction of cell stress, regarding antioxidative defense and endoplasmatic reticulum stress. We demonstrated similar cytocompatibility of PMMA loaded with AgNP compared to plain PMMA or PMMA loaded with gentamicin. There was no decrease in cell number, viability and osteogenic differentiation and no induction of cell stress for all three PMMA variants after 21 days. Addition of gentamicin to AgNP-loaded PMMA led to a slight decrease in osteogenic differentiation. Also an increase in cell stress was detectable for PMMA loaded with gentamicin and AgNP. In conclusion, supplementation of PMMA bone cement with gentamicin, AgNP, and both results in bone implants with an antibacterial potency and suitable cytocompatibility in MSCs and MSC-OM.

Development of a Preclinical Orthotopic Xenograft Model of Ewing Sarcoma and Other Human Malignant Bone Disease Using Advanced In Vivo Imaging

PubMed Central

Batey, Michael A.; Almeida, Gilberto S.; Wilson, Ian; Dildey, Petra; Sharma, Abhishek; Blair, Helen; Hide, I. Geoff; Heidenreich, Olaf; Vormoor, Josef; Maxwell, Ross J.; Bacon, Chris M.

2014-01-01

Ewing sarcoma and osteosarcoma represent the two most common primary bone tumours in childhood and adolescence, with bone metastases being the most adverse prognostic factor. In prostate cancer, osseous metastasis poses a major clinical challenge. We developed a preclinical orthotopic model of Ewing sarcoma, reflecting the biology of the tumour-bone interactions in human disease and allowing in vivo monitoring of disease progression, and compared this with models of osteosarcoma and prostate carcinoma. Human tumour cell lines were transplanted into non-obese diabetic/severe combined immunodeficient (NSG) and Rag2−/−/γc−/− mice by intrafemoral injection. For Ewing sarcoma, minimal cell numbers (1000–5000) injected in small volumes were able to induce orthotopic tumour growth. Tumour progression was studied using positron emission tomography, computed tomography, magnetic resonance imaging and bioluminescent imaging. Tumours and their interactions with bones were examined by histology. Each tumour induced bone destruction and outgrowth of extramedullary tumour masses, together with characteristic changes in bone that were well visualised by computed tomography, which correlated with post-mortem histology. Ewing sarcoma and, to a lesser extent, osteosarcoma cells induced prominent reactive new bone formation. Osteosarcoma cells produced osteoid and mineralised “malignant” bone within the tumour mass itself. Injection of prostate carcinoma cells led to osteoclast-driven osteolytic lesions. Bioluminescent imaging of Ewing sarcoma xenografts allowed easy and rapid monitoring of tumour growth and detection of tumour dissemination to lungs, liver and bone. Magnetic resonance imaging proved useful for monitoring soft tissue tumour growth and volume. Positron emission tomography proved to be of limited use in this model. Overall, we have developed an orthotopic in vivo model for Ewing sarcoma and other primary and secondary human bone malignancies, which resemble the human disease. We have shown the utility of small animal bioimaging for tracking disease progression, making this model a useful assay for preclinical drug testing. PMID:24409320

Engineering a humanized bone organ model in mice to study bone metastases.

PubMed

Martine, Laure C; Holzapfel, Boris M; McGovern, Jacqui A; Wagner, Ferdinand; Quent, Verena M; Hesami, Parisa; Wunner, Felix M; Vaquette, Cedryck; De-Juan-Pardo, Elena M; Brown, Toby D; Nowlan, Bianca; Wu, Dan Jing; Hutmacher, Cosmo Orlando; Moi, Davide; Oussenko, Tatiana; Piccinini, Elia; Zandstra, Peter W; Mazzieri, Roberta; Lévesque, Jean-Pierre; Dalton, Paul D; Taubenberger, Anna V; Hutmacher, Dietmar W

2017-04-01

Current in vivo models for investigating human primary bone tumors and cancer metastasis to the bone rely on the injection of human cancer cells into the mouse skeleton. This approach does not mimic species-specific mechanisms occurring in human diseases and may preclude successful clinical translation. We have developed a protocol to engineer humanized bone within immunodeficient hosts, which can be adapted to study the interactions between human cancer cells and a humanized bone microenvironment in vivo. A researcher trained in the principles of tissue engineering will be able to execute the protocol and yield study results within 4-6 months. Additive biomanufactured scaffolds seeded and cultured with human bone-forming cells are implanted ectopically in combination with osteogenic factors into mice to generate a physiological bone 'organ', which is partially humanized. The model comprises human bone cells and secreted extracellular matrix (ECM); however, other components of the engineered tissue, such as the vasculature, are of murine origin. The model can be further humanized through the engraftment of human hematopoietic stem cells (HSCs) that can lead to human hematopoiesis within the murine host. The humanized organ bone model has been well characterized and validated and allows dissection of some of the mechanisms of the bone metastatic processes in prostate and breast cancer.

Bone regeneration assessment by optical coherence tomography and MicroCT synchrotron radiation

NASA Astrophysics Data System (ADS)

Negrutiu, Meda L.; Sinescu, Cosmin; Canjau, Silvana; Manescu, Adrian; Topalá, Florin I.; Hoinoiu, Bogdan; Romînu, Mihai; Márcáuteanu, Corina; Duma, Virgil; Bradu, Adrian; Podoleanu, Adrian G.

2013-06-01

Bone grafting is a commonly performed surgical procedure to augment bone regeneration in a variety of orthopaedic and maxillofacial procedures, with autologous bone being considered as the "gold standard" bone-grafting material, as it combines all properties required in a bone-graft material: osteoinduction (bone morphogenetic proteins - BMPs - and other growth factors), osteogenesis (osteoprogenitor cells) and osteoconduction (scaffold). The problematic elements of bone regenerative materials are represented by their quality control methods, the adjustment of the initial bone regenerative material, the monitoring (noninvasive, if possible) during their osteoconduction and osteointegration period and biomedical evaluation of the new regenerated bone. One of the research directions was the interface investigation of the regenerative bone materials and their behavior at different time periods on the normal femoral rat bone. 12 rat femurs were used for this investigation. In each ones a 1 mm diameter hole were drilled and a bone grafting material was inserted in the artificial defect. The femurs were removed after one, three and six months. The defects repaired by bone grafting material were evaluated by optical coherence tomography working in Time Domain Mode at 1300 nm. Three dimensional reconstructions of the interfaces were generated. The validations of the results were evaluated by microCT. Synchrotron Radiation allows achieving high spatial resolution images to be generated with high signal-to-noise ratio. In addition, Synchrotron Radiation allows acquisition of volumes at different energies and volume subtraction to enhance contrast. Evaluation of the bone grafting material/bone interface with noninvasive methods such as optical coherence tomography could act as a valuable procedure that can be use in the future in the usual clinical techniques. The results were confirmed by microCT. Optical coherence tomography can be performed in vivo and can provide a qualitative and quantitative evaluation of the bone augmentation procedure.

Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

PubMed Central

Petersen, Richard C.

2014-01-01

The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical semiconductors, stress transfer, additives with low thermal PMC processing and new coating possibilities. PMID:25635227

The skeletal vascular system - Breathing life into bone tissue.

PubMed

Stegen, Steve; Carmeliet, Geert

2017-08-26

During bone development, homeostasis and repair, a dense vascular system provides oxygen and nutrients to highly anabolic skeletal cells. Characteristic for the vascular system in bone is the serial organization of two capillary systems, each typified by specific morphological and physiological features. Especially the arterial capillaries mediate the growth of the bone vascular system, serve as a niche for skeletal and hematopoietic progenitors and couple angiogenesis to osteogenesis. Endothelial cells and osteoprogenitor cells interact not only physically, but also communicate to each other by secretion of growth factors. A vital angiogenic growth factor is vascular endothelial growth factor and its expression in skeletal cells is controlled by osteogenic transcription factors and hypoxia signaling, whereas the secretion of angiocrine factors by endothelial cells is regulated by Notch signaling, blood flow and possibly hypoxia. Bone loss and impaired fracture repair are often associated with reduced and disorganized blood vessel network and therapeutic targeting of the angiogenic response may contribute to enhanced bone regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Material model of pelvic bone based on modal analysis: a study on the composite bone.

PubMed

Henyš, Petr; Čapek, Lukáš

2017-02-01

Digital models based on finite element (FE) analysis are widely used in orthopaedics to predict the stress or strain in the bone due to bone-implant interaction. The usability of the model depends strongly on the bone material description. The material model that is most commonly used is based on a constant Young's modulus or on the apparent density of bone obtained from computer tomography (CT) data. The Young's modulus of bone is described in many experimental works with large variations in the results. The concept of measuring and validating the material model of the pelvic bone based on modal analysis is introduced in this pilot study. The modal frequencies, damping, and shapes of the composite bone were measured precisely by an impact hammer at 239 points. An FE model was built using the data pertaining to the geometry and apparent density obtained from the CT of the composite bone. The isotropic homogeneous Young's modulus and Poisson's ratio of the cortical and trabecular bone were estimated from the optimisation procedure including Gaussian statistical properties. The performance of the updated model was investigated through the sensitivity analysis of the natural frequencies with respect to the material parameters. The maximal error between the numerical and experimental natural frequencies of the bone reached 1.74 % in the first modal shape. Finally, the optimised parameters were matched with the data sheets of the composite bone. The maximal difference between the calibrated material properties and that obtained from the data sheet was 34 %. The optimisation scheme of the FE model based on the modal analysis data provides extremely useful calibration of the FE models with the uncertainty bounds and without the influence of the boundary conditions.

Prostate Cancer Cell–Stromal Cell Cross-Talk via FGFR1 Mediates Antitumor Activity of Dovitinib in Bone Metastases

PubMed Central

Wan, Xinhai; Corn, Paul G.; Yang, Jun; Palanisamy, Nallasivam; Starbuck, Michael W.; Efstathiou, Eleni; Li-Ning Tapia, Elsa M.; Zurita, Amado J.; Aparicio, Ana; Ravoori, Murali K.; Vazquez, Elba S.; Robinson, Dan R.; Wu, Yi-Mi; Cao, Xuhong; Iyer, Matthew K.; McKeehan, Wallace; Kundra, Vikas; Wang, Fen; Troncoso, Patricia; Chinnaiyan, Arul M.; Logothetis, Christopher J.; Navone, Nora M.

2015-01-01

Bone is the most common site of prostate cancer (PCa) progression to a therapy-resistant, lethal phenotype. We found that blockade of fibroblast growth factor receptors (FGFRs) with the receptor tyrosine kinase inhibitor dovitinib has clinical activity in a subset of men with castration-resistant PCa and bone metastases. Our integrated analyses suggest that FGF signaling mediates a positive feedback loop between PCa cells and bone cells and that blockade of FGFR1 in osteoblasts partially mediates the antitumor activity of dovitinib by improving bone quality and by blocking PCa cell–bone cell interaction. These findings account for clinical observations such as reductions in lesion size and intensity on bone scans, lymph node size, and tumor-specific symptoms without proportional declines in prostate-specific antigen concentration. Our findings suggest that targeting FGFR has therapeutic activity in advanced PCa and provide direction for the development of therapies with FGFR inhibitors. PMID:25186177

Composite material

DOEpatents

Hutchens, Stacy A [Knoxville, TN; Woodward, Jonathan [Solihull, GB; Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN

2012-02-07

A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

[Osteostimulating effect of bone xenograft on bone tissue regeneration].

PubMed

Balin, V N; Balin, D V; Iordanishvili, A K; Musikin, M I

2015-01-01

The aim of experimental case-control study performed in 28 dogs divided in 2 groups was to assess local tissue reactions on bone xenograft transplantation; dynamics of bone remodeling and formation at the site of bone defect wall contacting with bone xenograft; dynamics and mechanisms of xenograft remodeling. Transplantation of xenograft in conventional bone defects did not cause inflammatory of destructive reactions because of high biocompatibility of the material. At transplantation site active fibrous bone trabeculae formation filling the spaces between xenograft participles was observed. On the 90th day newly formed bone showed lammelar structure. Simultaneously from the 42d day the invasion of cell elements from recipient bed into the material was seen leading to xenograft resorption. The observed dynamics may be assessed as gradual substitution of xenograft with newly formed host bone structures.

Ferromagnetic resonance in the ethmoid bones of salmon and silver carp

NASA Astrophysics Data System (ADS)

Gorobets, Svitlana; Gorobets, Oksana; Golub, Volodymyr; Gromnadska, Marina

2017-10-01

The detection of biogenic magnetic nanoparticles (BMN) with different magnetic properties in biological material was done using magnetic resonance (MR) spectroscopy. MR spectra of biological material of ethmoid bone of salmon (containing ferritin and BMN), bacteria E. coli K13 (containing ferritin and without BMN), yeast S. cerevisiae (without ferritin or BMN) and ethmoid bone of silver carp (containing ferritin and not investigated for the presence of BMN) were investigated. The analysis of MR spectra shows that S. cerevisiae cells produce much lower signal MR than samples of ethmoid bones of salmon and silver carp which is confirming conclusions about the presence of BMN and ferritin in the ethmoid bones of fishes. The narrow MR linewidth indicates that the magnetic particles in the ethmoid bones of salmon and silver carp are in monodisperse state. The presence of a broad line and the absence of a narrow peak in MR spectrum of E. coli K13 cells are typical for ferritin.

How B cells influence bone biology in health and disease.

PubMed

Horowitz, Mark C; Fretz, Jackie A; Lorenzo, Joseph A

2010-09-01

It is now well established that important regulatory interactions occur between the cells in the hematopoietic, immune and skeletal systems (osteoimmunology). B lymphocytes (B cells) are responsible for the generation and production of antibodies or immunoglobulins in the body. Together with T cells these lymphocytes comprise the adaptive immune system, which allows an individual to develop specific responses to an infection and retain memory of that infection, allowing for a faster and more robust response if that same infection occurs again. In addition to this immune function, B cells have a close and multifaceted relationship with bone cells. B cells differentiate from hematopoietic stem cells (HSCs) in supportive niches found on endosteal bone surfaces. Cells in the osteoblast lineage support HSC and B cell differentiation in these niches. B cell differentiation is regulated, at least in part, by a series of transcription factors that function in a temporal manner. While these transcription factors are required for B cell differentiation, their loss causes profound changes in the bone phenotype. This is due, in part, to the close relationship between macrophage/osteoclast and B cell differentiation. Cross talk between B cells and bone cells is reciprocal with defects in the RANKL-RANK, OPG signaling axis resulting in altered bone phenotypes. While the role of B cells during normal bone remodeling appears minimal, activated B cells play an important role in many inflammatory diseases with associated bony changes. This review examines the relationship between B cells and bone cells and how that relationship affects the skeleton and hematopoiesis during health and disease. Copyright 2010 Elsevier Inc. All rights reserved.

Brucella and Osteoarticular Cell Activation: Partners in Crime

PubMed Central

Giambartolomei, Guillermo H.; Arriola Benitez, Paula C.; Delpino, M. Victoria

2017-01-01

Osteoarticular brucellosis is the most common presentation of human active disease although its prevalence varies widely. The three most common forms of osteoarticular involvement are sacroiliitis, spondylitis, and peripheral arthritis. The molecular mechanisms implicated in bone damage have been recently elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and the receptor activator of nuclear factor kappa-B ligand (RANKL)-the natural modulator of bone homeostasis are involved. These processes are driven by inflammatory cells, like monocytes/macrophages, neutrophils, Th17 CD4+ T, and B cells. In addition, Brucella abortus has a direct effect on osteoarticular cells and tilts homeostatic bone remodeling. These bacteria inhibit bone matrix deposition by osteoblasts (the only bone cells involved in bone deposition), and modify the phenotype of these cells to produce matrix metalloproteinases (MMPs) and cytokine secretion, contributing to bone matrix degradation. B. abortus also affects osteoclasts (cells naturally involved in bone resorption) by inducing an increase in osteoclastogenesis and osteoclast activation; thus, increasing mineral and organic bone matrix resorption, contributing to bone damage. Given that the pathology induced by Brucella species involved joint tissue, experiments conducted on synoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits synoviocyte apoptosis. Brucella is an intracellular bacterium that replicates preferentially in the endoplasmic reticulum of macrophages. The analysis of B. abortus-infected synoviocytes indicated that bacteria also replicate in their reticulum suggesting that they could use this cell type for intracellular replication during the osteoarticular localization of the disease. Finally, the molecular mechanisms of osteoarticular brucellosis discovered recently shed light on how the interaction between B. abortus and immune and osteoarticular cells may play an important role in producing damage in joint and bone. PMID:28265268

Hydroxyapatite/collagen bone-like nanocomposite.

PubMed

Kikuchi, Masanori

2013-01-01

Our group has succeeded to synthesize material with bone-like nanostructure and bone-like inorganic and organic composition via self-organization mechanism between them using simultaneous titration method under controlled pH and temperature. The hydroxyapatite/collagen (HAp/Col) bone-like nanocomposite completely incorporated into bone remodeling process to be substituted by new bone. Cells cultured on the HAp/Col revealed very interesting reactions. Osteoblast-like MG63 cells showed upregulation of alkaline phosphatase >3 times greater than MG63 cells cultured on tissue culture polystyrene (TCPS). MG63 cells 3-dimensionally cultured in a "HAp/Col sponge," a porous HAp/Col having sponge-like viscoelasticity, accumulated calcium phosphate nodules on extracellular matrices they secreted. Bone marrow cells co-cultured with osteoblasts on HAp/Col differentiated to osteoclasts without differentiation supplements. This phenomenon is not found in cells cultured on hydroxyapatite ceramics and TCPS, and rarely in cells cultured on dentin. These results suggest that HAp/Col is a good candidate for tissue engineering of bone as well as bone filler. In a clinical test as a bone filler, the HAp/Col sponge was significantly better than porous β-tricalcium phosphate. The HAp/Col sponge has been approved by the Japanese government and will be used as greatly needed bone filler in patients. In addition to the above, HAp/Col coating on titanium revealed higher osteo-conductivity than HAp-coated titanium and bare titanium and improved direct bonding between titanium and newly formed bone. The HAp/Col coating may be used for metal devices requiring osseointegration.

Applications of Metals for Bone Regeneration.

PubMed

Glenske, Kristina; Donkiewicz, Phil; Köwitsch, Alexander; Milosevic-Oljaca, Nada; Rider, Patrick; Rofall, Sven; Franke, Jörg; Jung, Ole; Smeets, Ralf; Schnettler, Reinhard; Wenisch, Sabine; Barbeck, Mike

2018-03-12

The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum . In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

Applications of Metals for Bone Regeneration

PubMed Central

Glenske, Kristina; Donkiewicz, Phil; Köwitsch, Alexander; Milosevic-Oljaca, Nada; Rider, Patrick; Rofall, Sven; Franke, Jörg; Jung, Ole; Smeets, Ralf; Schnettler, Reinhard; Wenisch, Sabine

2018-01-01

The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration. PMID:29534546

Transcriptomic profile induced in bone marrow mesenchymal stromal cells after interaction with multiple myeloma cells: implications in myeloma progression and myeloma bone disease

PubMed Central

Garcia-Gomez, Antonio; Las Rivas, Javier De; Ocio, Enrique M.; Díaz-Rodríguez, Elena; Montero, Juan C.; Martín, Montserrat; Blanco, Juan F.; Sanchez-Guijo, Fermín M.; Pandiella, Atanasio; San Miguel, Jesús F.; Garayoa, Mercedes

2014-01-01

Despite evidence about the implication of the bone marrow (BM) stromal microenvironment in multiple myeloma (MM) cell growth and survival, little is known about the effects of myelomatous cells on BM stromal cells. Mesenchymal stromal cells (MSCs) from healthy donors (dMSCs) or myeloma patients (pMSCs) were co-cultured with the myeloma cell line MM.1S, and the transcriptomic profile of MSCs induced by this interaction was analyzed. Deregulated genes after co-culture common to both d/pMSCs revealed functional involvement in tumor microenvironment cross-talk, myeloma growth induction and drug resistance, angiogenesis and signals for osteoclast activation and osteoblast inhibition. Additional genes induced by co-culture were exclusively deregulated in pMSCs and predominantly associated to RNA processing, the ubiquitine-proteasome pathway, cell cycle regulation, cellular stress and non-canonical Wnt signaling. The upregulated expression of five genes after co-culture (CXCL1, CXCL5 and CXCL6 in d/pMSCs, and Neuregulin 3 and Norrie disease protein exclusively in pMSCs) was confirmed, and functional in vitro assays revealed putative roles in MM pathophysiology. The transcriptomic profile of pMSCs co-cultured with myeloma cells may better reflect that of MSCs in the BM of myeloma patients, and provides new molecular insights to the contribution of these cells to MM pathophysiology and to myeloma bone disease. PMID:25268740

Reactions and Surface Transformations of a Bone-Bioactive Material in a Simulated Microgravity Environment

NASA Technical Reports Server (NTRS)

Radin, S.; Ducheyne, P.; Ayyaswamy, P. S.

1999-01-01

A comprehensive program to investigate the expeditious in vitro formation of three-dimensional bone-like tissue is currently underway at the University of Pennsylvania. The study reported here forms a part of that program. Three-dimensional bone-like tissue structures may be grown under the simulated microgravity conditions of NASA designed Rotating Wall Bioreactor Vessels (RWV's). Such tissue growth will have wide clinical applications. In addition, an understanding of the fundamental changes that occur to bone cells under simulated microgravity would yield important information that will help in preventing or minimizing astronaut bone loss, a major health issue with travel or stay in space over long periods of time. The growth of three-dimensional bone-like tissue structures in RWV's is facilitated by the use of microcarriers which provide structural support. If the microcarrier material additionally promotes bone cell growth, then it is particularly advantageous to employ such microcarriers. We have found that reactive, bone-bioactive glass (BBG) is an attractive candidate for use as microcarrier material. Specifically, it has been found that BBG containing Ca- and P- oxides upregulates osteoprogenitor cells to osteoblasts. This effect on cells is preceded by BBG reactions in solution which result in the formation of a Ca-P surface layer. This surface further transforms to a bone-like mineral (i.e., carbonated crystalline hydroxyapatite (c-HA)). At normal gravity, time-dependent, immersion-induced BBG reactions and transformations are greatly affected both by variations in the composition of the milieu in which the glass is immersed and on the immersion conditions. However, the nature of BBG reactions and phase transformations under the simulated microgravity conditions of RWV's are unknown, and must be understood in order to successfully use BBG as microcarrier material in RWV'S. In this paper, we report some of our recent findings in this regard using experimental and numerical methods. BBG composition 45S5, the most reactive among known bone-bioactive glasses, was chosen for the study. BBG 45S5 behavior in physiological solutions was tested in simulated microgravity and compared with that at normal gravity. On the basis of our numerical study, we have chosen the BBG granule size to be in the range 40-70 microns, and a RWV rotational speed of 10 rpm. Our numerical study has shown that these parameters enable the microcarrier to remain suspended in the medium without experiencing collisions with the wall of the vessel. Immersion-induced changes in the solution composition and the material surface were analyzed after immersion.

Development of a Three-Dimensional Bone-Like Construct in a Soft Self-Assembling Peptide Matrix

PubMed Central

Marí-Buyé, Núria; Luque, Tomás; Navajas, Daniel

2013-01-01

This work describes the development of a three-dimensional (3D) model of osteogenesis using mouse preosteoblastic MC3T3-E1 cells and a soft synthetic matrix made out of self-assembling peptide nanofibers. By adjusting the matrix stiffness to very low values (around 120 Pa), cells were found to migrate within the matrix, interact forming a cell–cell network, and create a contracted and stiffer structure. Interestingly, during this process, cells spontaneously upregulate the expression of bone-related proteins such as collagen type I, bone sialoprotein, and osteocalcin, indicating that the 3D environment enhances their osteogenic potential. However, unlike MC3T3-E1 cultures in 2D, the addition of dexamethasone is required to acquire a final mature phenotype characterized by features such as matrix mineralization. Moreover, a slight increase in the hydrogel stiffness (threefold) or the addition of a cell contractility inhibitor (Rho kinase inhibitor) abrogates cell elongation, migration, and 3D culture contraction. However, this mechanical inhibition does not seem to noticeably affect the osteogenic process, at least at early culture times. This 3D bone model intends to emphasize cell–cell interactions, which have a critical role during tissue formation, by using a compliant unrestricted synthetic matrix. PMID:23157379

Synthetic Bone Substitute Engineered with Amniotic Epithelial Cells Enhances Bone Regeneration after Maxillary Sinus Augmentation

PubMed Central

Barboni, Barbara; Mangano, Carlo; Valbonetti, Luca; Marruchella, Giuseppe; Berardinelli, Paolo; Martelli, Alessandra; Muttini, Aurelio; Mauro, Annunziata; Bedini, Rossella; Turriani, Maura; Pecci, Raffaella; Nardinocchi, Delia; Zizzari, Vincenzo Luca; Tetè, Stefano; Piattelli, Adriano; Mattioli, Mauro

2013-01-01

Background Evidence has been provided that a cell-based therapy combined with the use of bioactive materials may significantly improve bone regeneration prior to dental implant, although the identification of an ideal source of progenitor/stem cells remains to be determined. Aim In the present research, the bone regenerative property of an emerging source of progenitor cells, the amniotic epithelial cells (AEC), loaded on a calcium-phosphate synthetic bone substitute, made by direct rapid prototyping (rPT) technique, was evaluated in an animal study. Material And Methods Two blocks of synthetic bone substitute (∼0.14 cm3), alone or engineered with 1×106 ovine AEC (oAEC), were grafted bilaterally into maxillary sinuses of six adult sheep, an animal model chosen for its high translational value in dentistry. The sheep were then randomly divided into two groups and sacrificed at 45 and 90 days post implantation (p.i.). Tissue regeneration was evaluated in the sinus explants by micro-computer tomography (micro-CT), morphological, morphometric and biochemical analyses. Results And Conclusions The obtained data suggest that scaffold integration and bone deposition are positively influenced by allotransplantated oAEC. Sinus explants derived from sheep grafted with oAEC engineered scaffolds displayed a reduced fibrotic reaction, a limited inflammatory response and an accelerated process of angiogenesis. In addition, the presence of oAEC significantly stimulated osteogenesis either by enhancing bone deposition or making more extent the foci of bone nucleation. Besides the modulatory role played by oAEC in the crucial events successfully guiding tissue regeneration (angiogenesis, vascular endothelial growth factor expression and inflammation), data provided herein show that oAEC were also able to directly participate in the process of bone deposition, as suggested by the presence of oAEC entrapped within the newly deposited osteoid matrix and by their ability to switch-on the expression of a specific bone-related protein (osteocalcin, OCN) when transplanted into host tissues. PMID:23696804

Engineering a biomimetic three-dimensional nanostructured bone model for breast cancer bone metastasis study.

PubMed

Zhu, Wei; Wang, Mian; Fu, Yebo; Castro, Nathan J; Fu, Sidney W; Zhang, Lijie Grace

2015-03-01

Traditional breast cancer (BrCa) bone metastasis models contain many limitations with regards to controllability, reproducibility and flexibility of design. In this study, a novel biomimetic bone microenvironment was created by integrating hydroxyapatite (HA) and native bioactive factors deposited by osteogenic induction of human bone marrow mesenchymal stem cells (MSCs) within a cytocompatible chitosan hydrogel. It was found that a 10% nanocrystalline HA (nHA) chitosan scaffold exhibited the highest BrCa adhesion and proliferation when compared to chitosan scaffolds with 20% nHA, 10% and 20% microcrystalline HA as well as amorphous HA. This 3-D tunable bone scaffold can provide a biologically relevant environment, increase cell-cell and cell-matrix interactions as found in native bone, and retain the behavior of BrCa cells with different metastasis potential (i.e. highly metastatic MDA-MB-231, less metastatic MCF-7 and transfected MDA-MB-231). The co-culture of MSCs and MDA-MB-231 in this bone model illustrated that MSCs have the capacity to upregulate the expression of the well-known metastasis-associated gene metadherin within BrCa cells. In summary, this study illustrates the ability of our 3-D bone model to create a biomimetic environment conducive to recapitulating the behavior of metastatic BrCa cells, making it a promising tool for in vitro BrCa cell bone metastasis study and for the discovery of potential therapeutics. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Adsorption of enamel matrix proteins to a bovine-derived bone grafting material and its regulation of cell adhesion, proliferation, and differentiation.

PubMed

Miron, Richard J; Bosshardt, Dieter D; Hedbom, Erik; Zhang, Yufeng; Haenni, Beat; Buser, Daniel; Sculean, Anton

2012-07-01

The use of various combinations of enamel matrix derivative (EMD) and grafting materials has been shown to promote periodontal wound healing/regeneration. However, the downstream cellular behavior of periodontal ligament (PDL) cells and osteoblasts has not yet been studied. Furthermore, it is unknown to what extent the bleeding during regenerative surgery may influence the adsorption of exogenous proteins to the surface of bone grafting materials and the subsequent cellular behavior. In the present study, the aim is to test EMD adsorption to the surface of natural bone mineral (NBM) particles in the presence of blood and determine the effect of EMD coating to NBM particles on downstream cellular pathways, such as adhesion, proliferation, and differentiation of primary human osteoblasts and PDL cells. NBM particles were precoated in various settings with EMD or human blood and analyzed for protein adsorption patterns via fluorescent imaging and high-resolution immunocytochemistry with an anti-EMD antibody. Cell attachment and cell proliferation were quantified using fluorescent double-stranded DNA-binding dye. Cell differentiation was analyzed using real-time polymerase chain reaction for genes encoding runt-related transcription factor 2, alkaline phosphatase (ALP), osteocalcin (OC), and collagen1α1 (COL1A1), and mineralization was assessed using red dye staining. Analysis of cell attachment and cell proliferation revealed significantly higher osteoblast and PDL cell attachment on EMD-coated surfaces when compared with control and blood-coated surfaces. EMD also stimulated release of growth factors and cytokines, including bone morphogenetic protein 2 and transforming growth factor β1. Moreover, there were significantly higher mRNA levels of osteoblast differentiation markers, including COL1A1, ALP, and OC, in osteoblasts and PDL cells cultured on EMD-coated NBM particles. The present results suggest that 1) EMD enhances osteoblast and PDL cell attachment, proliferation, and differentiation on NBM particles, and 2) blood contamination of the grafting material before mixing with EMD may inhibit EMD adsorption.

Computational modelling of the mechanics of trabecular bone and marrow using fluid structure interaction techniques.

PubMed

Birmingham, E; Grogan, J A; Niebur, G L; McNamara, L M; McHugh, P E

2013-04-01

Bone marrow found within the porous structure of trabecular bone provides a specialized environment for numerous cell types, including mesenchymal stem cells (MSCs). Studies have sought to characterize the mechanical environment imposed on MSCs, however, a particular challenge is that marrow displays the characteristics of a fluid, while surrounded by bone that is subject to deformation, and previous experimental and computational studies have been unable to fully capture the resulting complex mechanical environment. The objective of this study was to develop a fluid structure interaction (FSI) model of trabecular bone and marrow to predict the mechanical environment of MSCs in vivo and to examine how this environment changes during osteoporosis. An idealized repeating unit was used to compare FSI techniques to a computational fluid dynamics only approach. These techniques were used to determine the effect of lower bone mass and different marrow viscosities, representative of osteoporosis, on the shear stress generated within bone marrow. Results report that shear stresses generated within bone marrow under physiological loading conditions are within the range known to stimulate a mechanobiological response in MSCs in vitro. Additionally, lower bone mass leads to an increase in the shear stress generated within the marrow, while a decrease in bone marrow viscosity reduces this generated shear stress.

Combinatorial growth of oxide nanoscaffolds and its influence in osteoblast cell adhesion

NASA Astrophysics Data System (ADS)

Acevedo-Morantes, Claudia Y.; Irizarry-Ortiz, Roberto A.; Caceres-Valencia, Pablo G.; Singh, Surinder P.; Ramirez-Vick, Jaime E.

2012-05-01

We report a novel method for high-throughput investigations on cell-material interactions based on metal oxide nanoscaffolds. These scaffolds possess a continuous gradient of various titanium alloys allowing the compositional and morphological variation that could substantially improve the formation of an osseointegrative interface with bone. The model nanoscaffold has been fabricated on commercially pure titanium (cp-Ti) substrate with a compositional gradients of tin (Sn), chromium (Cr), and niobium (Nb) deposited using a combinatorial approach followed by annealing to create native oxide surface. As an invitro test system, the human fetal osteoblastic cell line (hFOB 1.19) has been used. Cell-adhesion of hFOB 1.19 cells and the suitability of these alloys have been evaluated for cell-morphology, cell-number, and protein adsorption. Although, cell-morphology was not affected by surface composition, cell-proliferation rates varied significantly with surface metal oxide composition; with the Sn- and Nb-rich regions showing the highest proliferation rate and the Cr-rich regions presenting the lowest. The results suggest that Sn and Nb rich regions on surface seems to promote hFOB 1.19 cell proliferation and may therefore be considered as implant material candidates that deserve further analysis.

Differential proteomic analysis of a human breast tumor and its matched bone metastasis identifies cell membrane and extracellular proteins associated with bone metastasis.

PubMed

Dumont, Bruno; Castronovo, Vincent; Peulen, Olivier; Blétard, Noëlla; Clézardin, Philippe; Delvenne, Philippe; De Pauw, Edwin A; Turtoi, Andrei; Bellahcène, Akeila

2012-04-06

The classical fate of metastasizing breast cancer cells is to seed and form secondary colonies in bones. The molecules closely associated with these processes are predominantly present at the cell surface and in the extracellular space, establishing the first contacts with the target tissue. In this study, we had the rare opportunity to analyze a bone metastatic lesion and its corresponding breast primary tumor obtained simultaneously from the same patient. Using mass spectrometry, we undertook a proteomic study on cell surface and extracellular protein-enriched material. We provide a repertoire of significantly modulated proteins, some with yet unknown roles in the bone metastatic process as well as proteins notably involved in cancer cell invasiveness and in bone metabolism. The comparison of these clinical data with those previously obtained using a human osteotropic breast cancer cell line highlighted an overlapping group of proteins. Certain differentially expressed proteins are validated in the present study using immunohistochemistry on a retrospective collection of breast tumors and matched bone metastases. Our exclusive set of selected proteins supports the setup of further investigations on both clinical samples and experimental bone metastasis models that will help to reveal the finely coordinated expression of proteins that favor the development of metastases in the bone microenvironment.

Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

PubMed Central

Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

2012-01-01

The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

Hydrogels with tunable stress relaxation regulate stem cell fate and activity

NASA Astrophysics Data System (ADS)

Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-Pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

2016-03-01

Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture.

Neoplastic Bone Marrow Niche: Hematopoietic and Mesenchymal Stem Cells

PubMed Central

Saki, Najmaldin; Abroun, Saeid; Farshdousti Hagh, Majid; Asgharei, Farahnaz

2011-01-01

The neoplastic niche comprises complex interactions between multiple cell types and molecules requiring cell-cell signaling as well as local secretion. These niches are important for both the maintenance of cancer stem cells and the induction of neoplastic cells survival and proliferation. Each niche contains a population of tumor stem cells supported by a closely associated vascular bed comprising mesenchyme-derived cells and extracellular matrix. Targeting cancer stem cells and neoplastic niche may provide new therapies to eradicate tumors. Much progress has been very recently made in the understanding of the cellular and molecular interactions in the microenvironment of neoplastic niches. This review article provides an overview of the neoplastic niches in the bone marrow. In addition to highlighting recent advances in the field, we will also discuss components of the niche and their signaling pathways. PMID:23508881

Patient-specific 3D microfluidic tissue model for multiple myeloma.

PubMed

Zhang, Wenting; Lee, Woo Y; Siegel, David S; Tolias, Peter; Zilberberg, Jenny

2014-08-01

In vitro culturing of primary multiple myeloma cells (MMC) has been a major challenge as this plasma cell malignancy depends on the bone marrow environment for its survival. Using a microfluidic platform to emulate the dynamic physiology of the bone marrow microenvironment, we report here a new approach for culturing difficult to preserve primary human MMC. The system uses a three-dimensional ossified tissue to mimic the tumor niche and recapitulate interactions between bone marrow cells and osteoblasts (OSB). To this end, the human fetal OSB cell line hFOB 1.19 was cultured in an eight-chamber microfluidic culture device to facilitate the seeding of mononuclear cells from bone marrow aspirates from three multiple myeloma patients. Optical microscopy, used for real-time monitoring of mononuclear cell interactions with the ossified tissue, confirmed that these are drawn toward the OSB layer. After 3 weeks, cocultures were characterized by flow cytometry to evaluate the amount of expansion of primary MMC (with CD138(+) and CD38(+)CD56(+) phenotypes) in this system. For each of the three patients analyzed, bone marrow mononuclear cells underwent, on an average, 2 to 5 expansions; CD38(+)CD56(+) cells underwent 1 to 3 expansions and CD138(+) cells underwent 2.5 to 4.6 expansions. This approach is expected to provide a new avenue that can facilitate: (1) testing of personalized therapeutics for multiple myeloma patients; (2) evaluation of new drugs without the need for costly animal models; and (3) studying the biology of multiple myeloma, and in particular, the mechanisms responsible for drug resistance and relapse.

Graphene supports in vitro proliferation and osteogenic differentiation of goat adult mesenchymal stem cells: potential for bone tissue engineering.

PubMed

Elkhenany, Hoda; Amelse, Lisa; Lafont, Andersen; Bourdo, Shawn; Caldwell, Marc; Neilsen, Nancy; Dervishi, Enkeleda; Derek, Oshin; Biris, Alexandru S; Anderson, David; Dhar, Madhu

2015-04-01

Current treatments for bone loss injuries involve autologous and allogenic bone grafts, metal alloys and ceramics. Although these therapies have proved useful, they suffer from inherent challenges, and hence, an adequate bone replacement therapy has not yet been found. We hypothesize that graphene may be a useful nanoscaffold for mesenchymal stem cells and will promote proliferation and differentiation into bone progenitor cells. In this study, we evaluate graphene, a biocompatible inert nanomaterial, for its effect on in vitro growth and differentiation of goat adult mesenchymal stem cells. Cell proliferation and differentiation are compared between polystyrene-coated tissue culture plates and graphene-coated plates. Graphitic materials are cytocompatible and support cell adhesion and proliferation. Importantly, cells seeded on to oxidized graphene films undergo osteogenic differentiation in fetal bovine serum-containing medium without the addition of any glucocorticoid or specific growth factors. These findings support graphene's potential to act as an osteoinducer and a vehicle to deliver mesenchymal stem cells, and suggest that the combination of graphene and goat mesenchymal stem cells provides a promising construct for bone tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd.

Reciprocal regulation of adipocyte and osteoblast differentiation of mesenchymal stem cells by Eupatorium japonicum prevents bone loss and adiposity increase in osteoporotic rats.

PubMed

Kim, Min-Ji; Jang, Woo-Seok; Lee, In-Kyoung; Kim, Jong-Keun; Seong, Ki-Seung; Seo, Cho-Rong; Song, No-Joon; Bang, Min-Hyuk; Lee, Young Min; Kim, Haeng Ran; Park, Ki-Moon; Park, Kye Won

2014-07-01

Pathological increases in adipogenic potential with decreases in osteogenic differentiation occur in osteoporotic bone marrow cells. Previous studies have shown that bioactive materials isolated from natural products can reciprocally regulate adipogenic and osteogenic fates of bone marrow cells. In this study, we showed that Eupatorium japonicum stem extracts (EJE) suppressed lipid accumulation and inhibited the expression of adipocyte markers in multipotent C3H10T1/2 and primary bone marrow cells. Conversely, EJE stimulated alkaline phosphatase activity and induced the expression of osteoblast markers in C3H10T1/2 and primary bone marrow cells. Daily oral administration of 50 mg/kg of EJE for 6 weeks to ovariectomized rats prevented body weight increase and bone mineral density decrease. Finally, activity-guided fractionation led to the identification of coumaric acid and coumaric acid methyl ester as bioactive anti-adipogenic and pro-osteogenic components in EJE. Taken together, our data indicate a promising possibility of E. japonicum as a functional food and as a therapeutic intervention for preventing osteoporosis and bone fractures.

Role of HIF-1α in skeletal development

PubMed Central

Wan, Chao; Shao, Jin; Gilbert, Shawn R.; Riddle, Ryan C.; Long, Fanxin; Johnson, Randall S.; Schipani, Ernestina; Clemens, Thomas L.

2011-01-01

Angiogenesis and osteogenesis are tightly coupled during bone development and regeneration. Mesenchymal cells in the developing stroma elicit angiogenic signals to recruit new blood vessels into bone. Reciprocal signals, likely emanating from the incoming vascular endothelium, stimulate mesenchymal cell specification through additional interactions with cells within the vascular stem cell niche. The hypoxia-inducible factor-1 alpha (HIF-1) pathway has been identified as a key component in this process. We demonstrated that overexpression of HIF-1 in mature osteoblasts through disruption of the von Hippel-Lindau protein profoundly increases angiogenesis and osteogenesis; these processes appear to be coupled by cell nonautonomous mechanisms involving the action of vascular endothelial growth factor (VEGF) on the endothelial cells. The same occurred in the model of injury-mediated bone regeneration (distraction osteogenesis). Surprisingly, manipulation of HIF-1 does not influence angiogenesis of the skull bones, where earlier activation of HIF-1 in the condensing mesenchyme upregulates osterix during cranial bone formation. PMID:20392254

Curcumin-functionalized silk materials for enhancing adipogenic differentiation of bone marrow-derived human mesenchymal stem cells

PubMed Central

Li, Chunmei; Luo, Tingting; Zheng, Zhaozhu; Murphy, Amanda R.; Wang, Xiaoqin; Kaplan, David L.

2014-01-01

Curcumin, a natural phenolic compound derived from the plant Curcuma longa, was physically entrapped and stabilized in silk hydrogel films and its influence on human bone marrow-derived mesenchymal stem cells (hBMSCs) was assessed related to adipogenic differentiation. The presence of curcumin significantly reduced silk gelation time and changed the porous morphology of gel matrix, but did not change the formation of silk beta-sheet structure. Based on spectrofluorimetric analysis, curcumin likely interacted with hydrophobic residues in silk, interacting with the beta-sheet domains formed in the hydrogels. The antioxidant activity of silk film-associated curcumin remained functional over at least one month in both the dry and hydrated state. Negligible curcumin was released from silk hydrogel films over 48 hours incubation in aqueous solution. For hBMSCs cultured on silk films containing more than 0.25 mg/mL curcumin, cell proliferation was inhibited while adipogenesis was significantly promoted based on transcripts as well as oil red O staining. When hBMSCs were cultured in media containing free curcumin, both proliferation and adipogenesis of hBMSCs were inhibited when curcumin concentrations exceeded 5 μM, which is more than 1,000-times higher than the level of curcumin released from the films in aqueous solution. Thus, silk film-associated curcumin exhibited different effects on hBMSC proliferation and differentiation when compared to curcumin in solution. PMID:25132274

Dasatinib inhibits both osteoclast activation and prostate cancer PC-3-cell-induced osteoclast formation.

PubMed

Araujo, John C; Poblenz, Ann; Corn, Paul; Parikh, Nila U; Starbuck, Michael W; Thompson, Jerry T; Lee, Francis; Logothetis, Christopher J; Darnay, Bryant G

2009-11-01

Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC(50) of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts, and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases.

Synergetic effect of topological cue and periodic mechanical tension-stress on osteogenic differentiation of rat bone mesenchymal stem cells.

PubMed

Liu, Yao; Yang, Guang; Ji, Huanzhong; Xiang, Tao; Luo, En; Zhou, Shaobing

2017-06-01

Mesenchymal stem cells (MSCs) are able to self-renew and differentiate into tissues of mesenchymal origin, making them to be significant for cell-based therapies, such as metabolic bone diseases and bone repair. Regulating the differentiation of MSCs is significant for bone regeneration. Electrospun fibers mimicking natural extracellular matrix (ECM), is an effective artificial ECM to regulate the behaviors and fates of MSCs. The aligned electrospun fibers can modulate polar cell pattern of bone mesenchymal stem cells, which leads to more obvious osteogenic differentiation. Apart from the topographic effect of electrospun fibers, mechanical cues can also intervene the cell behaviors. In this study, the osteogenic differentiation of rat bone mesenchymal stem cells was evaluated, which were cultured on aligned/random electrospun fiber mats materials under mechanical tension intervention. Scanning electron microscope and immune-fluorescent staining were used to directly observe the polarity changing of cellular morphology and cytoskeleton. The results proved that aligned electrospun fibers could be more conducive to promote osteogenic differentiation of rat bone mesenchymal stem cells and this promotion of osteogenic differentiation was enhanced by tension intervention. These results were correlated to the quantitative real-time PCR assay. In general, culturing rat bone mesenchymal stem cells on electrospun fibers under the intervention of mechanical tension is an effective way to mimic a more real cellular microenvironment. Copyright © 2017 Elsevier B.V. All rights reserved.

Cells Recognize and Prefer Bone-like Hydroxyapatite: Biochemical Understanding of Ultrathin Mineral Platelets in Bone.

PubMed

Liu, Cuilian; Zhai, Halei; Zhang, Zhisen; Li, Yaling; Xu, Xurong; Tang, Ruikang

2016-11-09

Hydroxyapatite (HAP) nanocrystallites in all types of bones are distinguished by their ultrathin characteristics, which are uniaxially oriented with fibrillar collagen to uniquely expose the (100) faces. We speculate that living organisms prefer the specific crystal morphology and orientation of HAP because of the interactions between cells and crystals at the mineral-cell interface. Here, bone-like platy HAP (p-HAP) and two different rod-like HAPs were synthesized to investigate the ultrathin mineral modulating effect on cell bioactivity and bone generation. Cell viability and osteogenic differentiation of mesenchymal stem cells (MSCs) were significantly promoted by the platy HAP with (100) faces compared to rod-like HAPs with (001) faces as the dominant crystal orientation, which indicated that MSCs can recognize the crystal face and prefer the (100) HAP faces. This face-specific preference is dependent on the selective adsorption of fibronectin (FN), a plasma protein that plays a central role in cell adhesion, on the HAP surface. This selective adsorption is further confirmed by molecule dynamics (MD) simulation. Our results demonstrate that it is an intelligent choice for cells to use ultrathin HAP with a large (100) face as a basic building block in the hierarchical structure of bone, which is crucial to the promotion of MSCs osteoinductions during bone formation.

Enhanced bioactive scaffolds for bone tissue regeneration

NASA Astrophysics Data System (ADS)

Karnik, Sonali

Bone injuries are commonly termed as fractures and they vary in their severity and causes. If the fracture is severe and there is loss of bone, implant surgery is prescribed. The response to the implant depends on the patient's physiology and implant material. Sometimes, the compromised physiology and undesired implant reactions lead to post-surgical complications. [4, 5, 20, 28] Efforts have been directed towards the development of efficient implant materials to tackle the problem of post-surgical implant failure. [ 15, 19, 24, 28, 32]. The field of tissue engineering and regenerative medicine involves the use of cells to form a new tissue on bio-absorbable or inert scaffolds. [2, 32] One of the applications of this field is to regenerate the damaged or lost bone by using stem cells or osteoprogenitor cells on scaffolds that can integrate in the host tissue without causing any harmful side effects. [2, 32] A variety of natural, synthetic materials and their combinations have been used to regenerate the damaged bone tissue. [2, 19, 30, 32, 43]. Growth factors have been supplied to progenitor cells to trigger a sequence of metabolic pathways leading to cellular proliferation, differentiation and to enhance their functionality. [56, 57] The challenge persists to supply these proteins, in the range of nano or even picograms, and in a sustained fashion over a period of time. A delivery system has yet to be developed that would mimic the body's inherent mechanism of delivering the growth factor molecules in the required amount to the target organ or tissue. Titanium is the most preferred metal for orthopedic and orthodontic implants. [28, 46, 48] Even though it has better osteogenic properties as compared to other metals and alloys, it still has drawbacks like poor integration into the surrounding host tissue leading to bone resorption and implant failure. [20, 28, 35] It also faces the problem of postsurgical infections that contributes to the implant failure. [26, 37]. The focus of this dissertation was to design and develop novel implant materials for coating titanium to improve its biological properties. These natural and/or semi-synthetic materials improved cellular adhesion, biological response to the scaffolds and prevented growth of bacteria when they were enhanced with growth factor and anti-infective loaded nanotubes. The implant materials showed promise when tested in vitro for cell proliferation, differentiation and bacterial growth inhibition.

Guiding bone formation in a critical-sized defect and assessments.

PubMed

Jannetty, Joseph; Kolb, Eric; Boxberger, John; Deslauriers, Richard; Ganey, Timothy

2010-11-01

Development of alternatives to autologous bone has been served by many hypotheses and developments. Favorable properties of synthetic materials used currently in bone grafting support tissue differentiation without shielding capacity for integrated modeling. Ideally, new materials provide tissue compatibility and minimize patient morbidity and are attractive because of potential for in situ delivery, isothermal polymerization, porous structure, and nontoxic chemistry. For application in cranial bone, ability for materials to be laid adjacent to brain and offer postsurgical protection without neural risk is a critical asset. Kryptonite Bone Cement (KBC) meets the property criteria for cranial bone repair with regard to adhesive, conductive, and biologic transparency and US Food and Drug Administration approval for cranial bone void repair. To better delineate the morphology effective in cranial bone repair, a comparison was made between KBC and BoneSource, another material approved for the same indication. After Institutional Animal Care and Use Committee approval, the study assessed 24 rabbits, each with 2 separate cranial implants, to evaluate integration and absorption of the biomaterial at defined time points of 12, 18, 24, and 36 weeks. The 36-week assessment demonstrated near-complete resorption/integration of the BoneSource graft material. Bone was present within the biomaterial as well as independent of contact. The KBC was similarly integrated throughout the mass of the material, and new bone was in contact with the grafting material and also seen as separate islands of new bone. The bone demonstrated lamellar bone architecture with clear trabecular morphology. At higher magnification, the bone architecture can be clearly delineated, and comparison between the graft fillers is not obvious relative to the bone that has formed. Despite microscopic similarities, the most striking difference was maintenance of scaffold anatomy during bone regeneration. Kryptonite Bone Cement meets the criteria described in the introduction; properties of biologic transparency, osteoconductivity, and ergonomic utility offer other potential uses in bone repair. Key tenets of bone tissue regeneration observed in this analysis included adequate cell differentiation and tissue support. Bone that formed demonstrated lamellar rather than woven bone to suggest response to loading strain rather than merely biochemical precipitation. Over the 36-week study, the graft showed progressive bioabsorbable potential with calibrated replacement.

Mineralized alginate hydrogels using marine carbonates for bone tissue engineering applications.

PubMed

Diaz-Rodriguez, P; Garcia-Triñanes, P; Echezarreta López, M M; Santoveña, A; Landin, M

2018-09-01

The search for an ideal bone tissue replacement has led to the development of new composite materials designed to simulate the complex inorganic/organic structure of bone. The present work is focused on the development of mineralized calcium alginate hydrogels by the addition of marine derived calcium carbonate biomineral particles. Following a novel approach, we were able to obtain calcium carbonate particles of high purity and complex micro and nanostructure dependent on the source material. Three different types of alginates were selected to develop inorganic/organic scaffolds in order to correlate alginate composition with scaffold properties and cell behavior. The incorporation of calcium carbonates into alginate networks was able to promote extracellular matrix mineralization and osteoblastic differentiation of mesenchymal stem cells when added at 7 mg/ml. We demonstrated that the selection of the alginate type and calcium carbonate origin is crucial to obtain adequate systems for bone tissue engineering as they modulate the mechanical properties and cell differentiation. Copyright © 2018 Elsevier Ltd. All rights reserved.

The central nervous system (CNS)-independent anti-bone-resorptive activity of muscle contraction and the underlying molecular and cellular signatures.

PubMed

Qin, Weiping; Sun, Li; Cao, Jay; Peng, Yuanzhen; Collier, Lauren; Wu, Yong; Creasey, Graham; Li, Jianhua; Qin, Yiwen; Jarvis, Jonathan; Bauman, William A; Zaidi, Mone; Cardozo, Christopher

2013-05-10

Mechanisms by which muscle regulates bone are poorly understood. Electrically stimulated muscle contraction reversed elevations in bone resorption and increased Wnt signaling in bone-derived cells after spinal cord transection. Muscle contraction reduced resorption of unloaded bone independently of the CNS, through mechanical effects and, potentially, nonmechanical signals (e.g. myokines). The study provides new insights regarding muscle-bone interactions. Muscle and bone work as a functional unit. Cellular and molecular mechanisms underlying effects of muscle activity on bone mass are largely unknown. Spinal cord injury (SCI) causes muscle paralysis and extensive sublesional bone loss and disrupts neural connections between the central nervous system (CNS) and bone. Muscle contraction elicited by electrical stimulation (ES) of nerves partially protects against SCI-related bone loss. Thus, application of ES after SCI provides an opportunity to study the effects of muscle activity on bone and roles of the CNS in this interaction, as well as the underlying mechanisms. Using a rat model of SCI, the effects on bone of ES-induced muscle contraction were characterized. The SCI-mediated increase in serum C-terminal telopeptide of type I collagen (CTX) was completely reversed by ES. In ex vivo bone marrow cell cultures, SCI increased the number of osteoclasts and their expression of mRNA for several osteoclast differentiation markers, whereas ES significantly reduced these changes; SCI decreased osteoblast numbers, but increased expression in these cells of receptor activator of NF-κB ligand (RANKL) mRNA, whereas ES increased expression of osteoprotegerin (OPG) and the OPG/RANKL ratio. A microarray analysis revealed that ES partially reversed SCI-induced alterations in expression of genes involved in signaling through Wnt, FSH, parathyroid hormone (PTH), oxytocin, and calcineurin/nuclear factor of activated T-cells (NFAT) pathways. ES mitigated SCI-mediated increases in mRNA levels for the Wnt inhibitors DKK1, sFRP2, and sclerostin in ex vivo cultured osteoblasts. Our results demonstrate an anti-bone-resorptive activity of muscle contraction by ES that develops rapidly and is independent of the CNS. The pathways involved, particularly Wnt signaling, suggest future strategies to minimize bone loss after immobilization.

Oleic acid surfactant in polycaprolactone/hydroxyapatite-composites for bone tissue engineering.

PubMed

Cardoso, Guinea B C; Maniglio, Devid; Volpato, Fabio Z; Tondon, Abhishek; Migliaresi, Claudio; Kaunas, Roland R; Zavaglia, Cecilia A C

2016-08-01

Bone substitutes are required to repair osseous defects caused by a number of factors, such as traumas, degenerative diseases, and cancer. Autologous bone grafting is typically used to bridge bone defects, but suffers from chronic pain at the donor-site and limited availability of graft material. Tissue engineering approaches are being investigated as viable alternatives, which ideal scaffold should be biocompatible, biodegradable, and promote cellular interactions and tissue development, need to present proper mechanical and physical properties. In this study, poly(ε-caprolactone) (PCL), oleic acid (OA) and hydroxyapatite (HAp) were used to obtain films whose properties were investigated by contact angle, scanning electron microscopy, atomic force microscopy, tensile mechanical tests, and in vitro tests with U2OS human osteosarcoma cells by direct contact. Our results indicate that by using OA as surfactant/dispersant, it was possible to obtain a homogenous film with HAp. The PCL/OA/Hap sample had twice the roughness of the control (PCL) and a lower contact angle, indicating increased hydrophilicity of the film. Furthermore, mechanical testing showed that the addition of HAp decreased the load at yield point and tensile strength and increased tensile modulus, indicating a more brittle composition vs. PCL matrix. Preliminary cell culture experiments carried out with the films demonstrated that U2OS cells adhered and proliferated on all surfaces. The data demonstrate the improved dispersion of HAp using OA and the important consequences of this addition on the composite, unveiling the potentially of this composition for bone growth support. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1076-1082, 2016. © 2015 Wiley Periodicals, Inc.

Gelatin-Derived Graphene–Silicate Hybrid Materials Are Biocompatible and Synergistically Promote BMP9-Induced Osteogenic Differentiation of Mesenchymal Stem Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, Yulong; Qazvini, Nader Taheri; Zane, Kylie

Graphene-based materials are used in many fields but have found only limited applications in biomedicine, including bone tissue engineering. Here, we demonstrate that novel hybrid materials consisting of gelatin-derived graphene and silicate nanosheets of Laponite (GL) are biocompatible and promote osteogenic differentiation of mesenchymal stem cells (MSCs). Homogeneous cell attachment, long-term proliferation, and osteogenic differentiation of MSCs on a GL-scaffold were confirmed using optical microscopy and scanning electron microscopy. GL-powders made by pulverizing the GL-scaffold were shown to promote bone morphogenetic protein (BMP9)-induced osteogenic differentiation. GL-powders increased the alkaline phosphatase (ALP) activity in immortalized mouse embryonic fibroblasts but decreased themore » ALP activity in more-differentiated immortalized mouse adipose-derived cells. Note, however, that GL-powders promoted BMP9-induced calcium mineral deposits in both MSC lines, as assessed using qualitative and quantitative alizarin red assays. Furthermore, the expression of chondro-osteogenic regulator markers such as Runx2, Sox9, osteopontin, and osteocalcin was upregulated by the GL-powder, independent of BMP9 stimulation; although the powder synergistically upregulated the BMP9-induced Osterix expression, the adipogenic marker PPAR gamma was unaffected. Furthermore, in vivo stem cell implantation experiments demonstrated that GL-powder could significantly enhance the BMP9-induced ectopic bone formation from MSCs. Collectively, our results strongly suggest that the GL hybrid materials promote BMP9-induced osteogenic differentiation of MSCs and hold promise for the development of bone tissue engineering platforms.« less

The osteocyte: key player in regulating bone turnover

PubMed Central

Goldring, Steven R

2015-01-01

Osteocytes are the most abundant cell type in bone and are distributed throughout the mineralised bone matrix forming an interconnected network that ideally positions them to sense and to respond to local biomechanical and systemic stimuli to regulate bone remodelling and adaptation. The adaptive process is dependent on the coordinated activity of osteoclasts and osteoblasts that form a so called bone multicellular unit that remodels cortical and trabecular bone through a process of osteoclast-mediated bone resorption, followed by a phase of bone formation mediated by osteoblasts. Osteocytes mediate their effects on bone remodelling via both cell–cell interactions with osteoclasts and osteoblasts, but also via signaling through the release of soluble mediators. The remodelling process provides a mechanism for adapting the skeleton to local biomechanical factors and systemic hormonal influences and for replacing bone that has undergone damage from repetitive mechanical loading. PMID:26557372

Clay-Enriched Silk Biomaterials for Bone Formation

PubMed Central

Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

2011-01-01

The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

Bone tissue engineering using silica-based mesoporous nanobiomaterials:Recent progress.

PubMed

Shadjou, Nasrin; Hasanzadeh, Mohammad

2015-10-01

Bone disorders are of significant concern due to increase in the median age of our population. It is in this context that tissue engineering has been emerging as a valid approach to the current therapies for bone regeneration/substitution. Tissue-engineered bone constructs have the potential to alleviate the demand arising from the shortage of suitable autograft and allograft materials for augmenting bone healing. Silica based mesostructured nanomaterials possessing pore sizes in the range 2-50 nm and surface reactive functionalities have elicited immense interest due to their exciting prospects in bone tissue engineering. In this review we describe application of silica-based mesoporous nanomaterials for bone tissue engineering. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds and composites. Also, the effect of structural and textural properties of mesoporous materials on development of new biomaterials for production of bone implants and bone cements was discussed. Also, application of different mesoporous materials on construction of manufacture 3-dimensional scaffolds for bone tissue engineering was discussed. It begins by giving the reader a brief background on tissue engineering, followed by a comprehensive description of all the relevant components of silica-based mesoporous biomaterials on bone tissue engineering, going from materials to scaffolds and from cells to tissue engineering strategies that will lead to "engineered" bone. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanistic, Mathematical Model to Predict the Dynamics of Tissue Genesis in Bone Defects via Mechanical Feedback and Mediation of Biochemical Factors

PubMed Central

Moore, Shannon R.; Saidel, Gerald M.; Knothe, Ulf; Knothe Tate, Melissa L.

2014-01-01

The link between mechanics and biology in the generation and the adaptation of bone has been well studied in context of skeletal development and fracture healing. Yet, the prediction of tissue genesis within - and the spatiotemporal healing of - postnatal defects, necessitates a quantitative evaluation of mechano-biological interactions using experimental and clinical parameters. To address this current gap in knowledge, this study aims to develop a mechanistic mathematical model of tissue genesis using bone morphogenetic protein (BMP) to represent of a class of factors that may coordinate bone healing. Specifically, we developed a mechanistic, mathematical model to predict the dynamics of tissue genesis by periosteal progenitor cells within a long bone defect surrounded by periosteum and stabilized via an intramedullary nail. The emergent material properties and mechanical environment associated with nascent tissue genesis influence the strain stimulus sensed by progenitor cells within the periosteum. Using a mechanical finite element model, periosteal surface strains are predicted as a function of emergent, nascent tissue properties. Strains are then input to a mechanistic mathematical model, where mechanical regulation of BMP-2 production mediates rates of cellular proliferation, differentiation and tissue production, to predict healing outcomes. A parametric approach enables the spatial and temporal prediction of endochondral tissue regeneration, assessed as areas of cartilage and mineralized bone, as functions of radial distance from the periosteum and time. Comparing model results to histological outcomes from two previous studies of periosteum-mediated bone regeneration in a common ovine model, it was shown that mechanistic models incorporating mechanical feedback successfully predict patterns (spatial) and trends (temporal) of bone tissue regeneration. The novel model framework presented here integrates a mechanistic feedback system based on the mechanosensitivity of periosteal progenitor cells, which allows for modeling and prediction of tissue regeneration on multiple length and time scales. Through combination of computational, physical and engineering science approaches, the model platform provides a means to test new hypotheses in silico and to elucidate conditions conducive to endogenous tissue genesis. Next generation models will serve to unravel intrinsic differences in bone genesis by endochondral and intramembranous mechanisms. PMID:24967742

Chitosan based nanofibers in bone tissue engineering.

PubMed

Balagangadharan, K; Dhivya, S; Selvamurugan, N

2017-11-01

Bone tissue engineering involves biomaterials, cells and regulatory factors to make biosynthetic bone grafts with efficient mineralization for regeneration of fractured or damaged bones. Out of all the techniques available for scaffold preparation, electrospinning is given priority as it can fabricate nanostructures. Also, electrospun nanofibers possess unique properties such as the high surface area to volume ratio, porosity, stability, permeability and morphological similarity to that of extra cellular matrix. Chitosan (CS) has a significant edge over other materials and as a graft material, CS can be used alone or in combination with other materials in the form of nanofibers to provide the structural and biochemical cues for acceleration of bone regeneration. Hence, this review was aimed to provide a detailed study available on CS and its composites prepared as nanofibers, and their associated properties found suitable for bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Soluble factor(s) from bone marrow cells can rescue lethally irradiated mice by protecting endogenous hematopoietic stem cells.

PubMed

Zhao, Yi; Zhan, Yuxia; Burke, Kathleen A; Anderson, W French

2005-04-01

Ionizing radiation-induced myeloablation can be rescued via bone marrow transplantation (BMT) or administration of cytokines if given within 2 hours after radiation exposure. There is no evidence for the existence of soluble factors that can rescue an animal after a lethal dose of radiation when administered several hours postradiation. We established a system that could test the possibility for the existence of soluble factors that could be used more than 2 hours postirradiation to rescue animals. Animals with an implanted TheraCyte immunoisolation device (TID) received lethal-dose radiation and then normal bone marrow Lin- cells were loaded into the device (thereby preventing direct interaction between donor and recipient cells). Animal survival was evaluated and stem cell activity was tested with secondary bone marrow transplantation and flow cytometry analysis. Donor cell gene expression of five antiapoptotic cytokines was examined. Bone marrow Lin- cells rescued lethally irradiated animals via soluble factor(s). Bone marrow cells from the rescued animals can rescue and repopulate secondary lethally irradiated animals. Within the first 6 hours post-lethal-dose radiation, there is no significant change of gene expression of the known radioprotective factors TPO, SCF, IL-3, Flt-3 ligand, and SDF-1. Hematopoietic stem cells can be protected in lethally irradiated animals by soluble factors produced by bone marrow Lin- cells.

Method of tissue repair using a composite material

DOEpatents

Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

2016-03-01

A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

Method of tissue repair using a composite material

DOEpatents

Hutchens, Stacy A; Woodward, Jonathan; Evans, Barbara R; O'Neill, Hugh M

2014-03-18

A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

RIA fractions contain mesenchymal stroma cells with high osteogenic potency.

PubMed

Kuehlfluck, Pamela; Moghaddam, Arash; Helbig, Lars; Child, Christopher; Wildemann, Britt; Schmidmaier, Gerhard

2015-12-01

The gold standard for treatment of non-union is the transplantation of autologous bone from iliac crest. As an alternative, material can be harvested by femoral reaming with the Reamer-Irrigator-Aspirator(®) (RIA)-System. This material might be a source for human mesenchymal stroma cells (MSCs) with osteogenic potency. The aim of this study was the characterisation of cells harvested with the RIA system and the comparison of their properties with cells isolated from bone marrow ("BM") and fat tissue ("adipose"). The RIA material was separated into the liquid aspiration fraction ("liquid") and the solid RIA fraction. From the solid RIA fraction the cells were cultured either directly ("native") or after collagenase digestion and filtration ("filtrate"). Stem cell characteristics were analysed and the osteogenic potential was investigated in vitro and in vivo. Fat tissue and bone marrow were harvested from nine patients (three women, six males, with a mean of 48.1 years) with atrophic non-union RIA material. The cells were isolated and characterised by flow cytometry, three lineage differentiation capacities and colony-forming unit fibroblast assay. Gene expression profiles were performed and osteogenic differentiation in vivo was analysed. All three RIA fractions contained mesenchymal stromal cells (MSCs) as demonstrated by CFU-F assay, three linage differentiation and surface marker analysis. The RIA-MSCs exhibited a significantly higher osteogenic potential in vitro compared to adipose-MSCs, whereas no difference was seen compared to BM-MSCs. Quantitative RT-PCR analysis revealed an expression of osteogenic markers in all isolated cells. The implantation of MSCs with β-TCP scaffolds into the mice muscle showed significantly higher bone formation for the filtrate RIA-MSC, native RIA-MSC and BM-MSC groups compared to the adipose-MSC group. The filtrate RIA-MSCs formed twice as much new bone in vivo compared to BM-MSCs. The present study showed high potency of cells isolated by reaming. Even in the irrigation fluid, which is normally discarded, cells with the characteristics of stromal stem cells were isolated. In comparison to adipose-MSCs and BM-MSCs, the RIA-MSCs showed a similar or even better osteogenic potential in vitro and in vivo and this supports their usability in orthopaedic surgery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polyurethane foam scaffold as in vitro model for breast cancer bone metastasis.

PubMed

Angeloni, Valentina; Contessi, Nicola; De Marco, Cinzia; Bertoldi, Serena; Tanzi, Maria Cristina; Daidone, Maria Grazia; Farè, Silvia

2017-11-01

Breast cancer (BC) represents the most incident cancer case in women (29%), with high mortality rate. Bone metastasis occurs in 20-50% cases and, despite advances in BC research, the interactions between tumor cells and the metastatic microenvironment are still poorly understood. In vitro 3D models gained great interest in cancer research, thanks to the reproducibility, the 3D spatial cues and associated low costs, compared to in vivo and 2D in vitro models. In this study, we investigated the suitability of a poly-ether-urethane (PU) foam as 3D in vitro model to study the interactions between BC tumor-initiating cells and the bone microenvironment. PU foam open porosity (>70%) appeared suitable to mimic trabecular bone structure. The PU foam showed good mechanical properties under cyclic compression (E=69-109kPa), even if lower than human trabecular bone. The scaffold supported osteoblast SAOS-2 cell line proliferation, with no cytotoxic effects. Human adipose derived stem cells (ADSC) were cultured and differentiated into osteoblast lineage on the PU foam, as shown by alizarin red staining and RT-PCR, thus offering a bone biomimetic microenvironment to the further co-culture with BC derived tumor-initiating cells (MCFS). Tumor aggregates were observed after three weeks of co-culture by e-cadherin staining and SEM; modification in CaP distribution was identified by SEM-EDX and associated to the presence of tumor cells. In conclusion, we demonstrated the suitability of the PU foam to reproduce a bone biomimetic microenvironment, useful for the co-culture of human osteoblasts/BC tumor-initiating cells and to investigate their interaction. 3D in vitro models represent an outstanding alternative in the study of tumor metastases development, compared to traditional 2D in vitro cultures, which oversimplify the 3D tissue microenvironment, and in vivo studies, affected by low reproducibility and ethical issues. Several scaffold-based 3D in vitro models have been proposed to recapitulate the development of metastases in different body sites but, still, the crucial challenge is to correctly mimic the tissue to be modelled in terms of physical, mechanical and biological properties. Here, we prove the suitability of a porous polyurethane foam, synthesized using an appropriate formulaton, in mimicking the bone tissue microenvironment and in reproducing the metastatic colonization derived from human breast cancer, particularly evidencing the devastating effects on the bone extracellular matrix caused by metastatic spreading. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Hydrogel-embedded nanocrystalline hydroxyapatite granules (elastic blocks) based on a cross-linked polyvinylpyrrolidone as bone grafting substitute in a rat tibia model

PubMed Central

Dau, Michael; Ganz, Cornelia; Zaage, Franziska; Frerich, Bernhard; Gerber, Thomas

2017-01-01

Purpose The aim of this study was to examine the in vivo characteristics and levels of integration and degradation of a ready-to-use bone grafting block with elastic properties (elastic block) for the use in surgery. Materials and methods Thirty-six male Wistar rats underwent surgical creation of a well-defined bone defect in the tibia. All created defects – one per animal – were filled with an unsintered nanocrystalline hydroxyapatite embedded either with a non-cross-linked hydrogel carrier (CONT, n=18) or a cross-linked hydrogel carrier (elastic block [EB], n=18) based on polyvinylpyrrolidone (PVP) and silica sol, respectively. The animals were killed after 12 (n=12), 21 (n=12) and 63 days (n=12). The bone formation and defect healing were quantified by histomorphometric measurements made in paraffin sections. Additionally, immunohistochemical (tartrate-resistant acid phosphatase [TRAP] and alkaline phosphatase [aP]), antibody-based examinations (CD68) and energy-dispersive x-ray scattering measurements of silica atom concentration were carried out. Results A larger remaining bone defect area overall was observed in EB after 12 days and 21 days. After 63 days, similar areas of remaining bone defects were found. The amount of the remaining carrier material in EB overall was higher at all times. In CONT no residual carrier material was found at 12 days and later. CD68 analyses showed significantly lower level of CD68-positive marked cells after 21 days in CONT, and nonsignificant differences at 12 and 63 days, respectively. Additionally, a significantly higher level of aP-positive marked cells was observed in CONT after 12 days. Later on, the levels of aP-positive marked cells were slightly higher in EB (21 and 63 days). Furthermore, no significant differences regarding the level of TRAP-positive marked cells in each group were observed. Conclusion The bone substitute (EB) with the cross-linked PVP-based hydrogel carrier leads at the beginning to a higher amount of remaining carrier material and remaining bone substitute. This delayed degradation is supposed to be the reason for the observed lower level of bone remodeling and is caused by the irradiation changes (cross links) in the structure in PVP. PMID:29066890

[Effect of the compound of poly lactic-co-glycolic acid and bone marrow stromal cells modified by osteoprotegerin gene on the periodontal regeneration in Beagle dog periodontal defects].

PubMed

Zhou, Wei; Zhao, Chun-Hui; Mei, Ling-Xuan

2010-06-01

To evaluate the effect of the osteoprotegerin (OPG) gene-modified autologous bone marrow stromal cells (BMSCs) on regeneration of periodontal defects, and to provide new experimental evidence to explore the gene therapy for periodontal disease. pSecTag2/B-opg was transduced into BMSCs by lipofectamine 2000. The expression of OPG protein in the BMSCs was detected by immunocytochemistry and Western blot. Inverted phase contrast microscope and scanning electron microscopy (SEM) were used to observe the morphology and proliferation of the BMSCs(OPG) on on the surface of the poly lactic-co-glycolic (PLGA). Horizontal alveolar bone defect (4 mmx4 mmx 3 mm) were surgically created in the buccal aspect of the mandibular premolar, and were randomly assigned to receive BMSCs(OPG)-PLGA (cells/material/OPG), BMSCs-PLGA (cells/material), PLGA (material), or root planning only (blank control). The animals were euthanized at 6 weeks post surgery for histological analysis. The height of new alveolar bone and cementum and the formation of new connective tissue were analyzed and compared. All data were statistically analyzed using the q test. The BMSCs transfected by human OPG gene can highly express OPG protein. SEM observations demonstrated that BMSCs(OPG) were able to proliferate and massively colonize on the scaffolds structure. After 6 weeks, the height of new alveolar bone and cementum and the formation of new connective tissue were significantly greater in the experimental group than in the control groups (P < 0.05). BMSCs(OPG)-PLGA can significantly promote the regeneration of dog's periodontal bone defects. Gene therapy utilizing OPG may offer the potential for periodontal tissue engineering applications.

Control over Structure and Function of Peptide Amphiphile Supramolecular Assemblies through Molecular Design and Energy Landscapes

NASA Astrophysics Data System (ADS)

Tantakitti, Faifan

Supramolecular chemistry is a powerful tool to create a material of a defined structure with tunable properties. This strategy has led to catalytically active, bioactive, and environment-responsive materials, among others, that are valuable in applications ranging from sensor technology to energy and medicine. Supramolecular polymers formed by peptide amphiphiles (PAs) have been especially relevant in tissue regeneration due to their ability to form biocompatible structures and mimic many important signaling molecules in biology. These supramolecular polymers can form nanofibers that create networks which mimic natural extracellular matrices. PA materials have been shown to induce growth of blood vessels, bone, cartilage, and nervous tissue, among others. The work described in this thesis not only studied the relationship between molecular structure and functions of PA assemblies, but also uncovered a powerful link between the energy landscape of their supramolecular self-assembly and the ability of PA materials to interact with cells. In chapter 2, it is argued that fabricating fibrous nanostructures with defined mechanical properties and decoration with bioactive molecules is not sufficient to create a material that can effectively communicate with cells. By systemically placing the fibronectin-derived RGDS epitope at increasing distances from the surface of PA nanofibers through a linker of one to five glycine residues, integrin-mediated RGDS signaling was enhanced. The results suggested that the spatial presentation of an epitope on PA nanofibers strongly influences the bioactivity of the PA substrates. In further improving functionality of a PA-based scaffold to effectively direct cell growth and differentiation, chapter 3 explored the use of a cell microcarrier to compartmentalize and simultaneously tune insoluble and soluble signals in a single matrix. PA nanofibers were incorporated at the surface of the microcarrier in order to promote cell adhesion, while a controlled local release of the soluble growth factor bone morphogenetic protein 4 (BMP-4) was realized from the particle's core composed of cross-linked alginate. The alginate-core and PA-shell microparticles were found to allow independent tuning of the bioactivity of a PA and a release of the growth factor for specific signaling to cells. Using microcarriers which encapsulated BMP-4 and coated with RGDS PA nanofibers, it was shown that a control over spatial distribution, proliferation, and osteogenic differentiation of premyoblastic cells on the surface of microcarriers can be effectively achieved. Finally, in drastic contrast to the traditional approach to material development based on altering molecular structure, chapter 4 presents the energy landscapes in which supramolecular assemblies of unique architecture exist in different thermodynamic wells. Experimental results and calculations revealed that the energy landscapes are rooted in competing interactions between PA monomers, namely beta-sheet hydrogen bonds and repulsion among charged groups. Switching off or on the repulsive electrostatic interactions by changing the ionic strength promoted or suppressed the dominant ?-sheet hydrogen bonding interactions respectively. However, the dominant forces can prevail if the assemblies are above a certain size and thereby can exist in a kinetically trapped state. Preparative pathways involving dilution, annealing, and addition of salt were investigated in which the structures belonging to different energy states could be accessed and demonstrated that these energy landscapes involving competitive interactions was applicable not only to PA systems but also to a non-peptide supramolecular system based on pi-orbital overlaps as the dominant attraction among molecules and electrostatic repulsion. In chapter 5, structure and biological function relationships of long or short PA nanofibers are reported, and such fibers were prepared from identical monomers based on knowledge of their energy landscapes described in chapter 4. Biological experiments were performed to compare the cytotoxicity of solutions containing short or long PA assemblies, as well as the ability of PA substrates to support cell adhesion and growth. In one assay, short fibers killed cells faster than long fibers and a study of interactions between lipid membrane and PA fibers suggested that cell death occurred through disruption of cell membrane by intact fibers, as opposed to single PA monomers. In another assay, long fibers induced better cell-spreading than short ones when immobilized on a surface. Mechanical measurements on the PA substrates indicated a higher ability of long fibers to sustain a higher pulling force exerted by cells. In summary, this thesis highlights that function in PA supramolecular materials is not only connected to chemical structure but also to the positions of specific materials within their respective energy landscapes.

An update on the Application of Nanotechnology in Bone Tissue Engineering.

PubMed

Griffin, M F; Kalaskar, D M; Seifalian, A; Butler, P E

2016-01-01

Natural bone is a complex and hierarchical structure. Bone possesses an extracellular matrix that has a precise nano-sized environment to encourage osteoblasts to lay down bone by directing them through physical and chemical cues. For bone tissue regeneration, it is crucial for the scaffolds to mimic the native bone structure. Nanomaterials, with features on the nanoscale have shown the ability to provide the appropriate matrix environment to guide cell adhesion, migration and differentiation. This review summarises the new developments in bone tissue engineering using nanobiomaterials. The design and selection of fabrication methods and biomaterial types for bone tissue engineering will be reviewed. The interactions of cells with different nanostructured scaffolds will be discussed including nanocomposites, nanofibres and nanoparticles. Several composite nanomaterials have been able to mimic the architecture of natural bone. Bioceramics biomaterials have shown to be very useful biomaterials for bone tissue engineering as they have osteoconductive and osteoinductive properties. Nanofibrous scaffolds have the ability to provide the appropriate matrix environment as they can mimic the extracellular matrix structure of bone. Nanoparticles have been used to deliver bioactive molecules and label and track stem cells. Future studies to improve the application of nanomaterials for bone tissue engineering are needed.

Ethanol inhibits human bone cell proliferation and function in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friday, K.E.; Howard, G.A.

1991-06-01

The direct effects of ethanol on human bone cell proliferation and function were studied in vitro. Normal human osteoblasts from trabecular bone chips were prepared by collagenase digestion. Exposure of these osteoblasts to ethanol in concentrations of 0.05% to 1% for 22 hours induced a dose-dependent reduction in bone cell DNA synthesis as assessed by incorporation of 3H-thymidine. After 72 hours of ethanol exposure in concentrations of 0.01% to 1%, protein synthesis as measured by 3H-proline incorporation into trichbroacetic acid (TCA)-precipitable material was reduced in a dose-dependent manner. Human bone cell protein concentrations and alkaline phosphatase total activity were significantlymore » reduced after exposure to 1% ethanol for 72 hours, but not with lower concentrations of ethanol. This reduction in osteoblast proliferation and activity may partially explain the development of osteopenia in humans consuming excessive amounts of ethanol.« less

Tissue Reaction to a Novel Bone Substitute Material Fabricated With Biodegradable Polymer-Calcium Phosphate Nanoparticle Composite.

PubMed

Shimizu, Hideo; Jinno, Yohei; Ayukawa, Yasunori; Atsuta, Ikiru; Arahira, Takaaki; Todo, Mitsugu; Koyano, Kiyoshi

2016-10-01

The aim of this study was to evaluate the effectiveness of a novel bone substitute material fabricated using a biodegradable polymer-calcium phosphate nanoparticle composite. Porous structured poly-L-lactic acid (PLLA) and hydroxyapatite (HA) nanoparticle composite, which was fabricated using solid-liquid phase separation and freeze-drying methods, was grafted into bone defects created in rat calvarium or tibia. Rats were killed 4 weeks after surgery, and histological analyses were performed to evaluate new bone formation. Scanning electron microscopic observation showed the interconnecting pores within the material and the pore diameter was approximately 100 to 300 μm. HA nanoparticles were observed to be embedded into the PLLA beams. In the calvarial implantation model, abundant blood vessels and fibroblastic cells were observed penetrating into pores, and in the tibia model, newly formed bone was present around and within the composite. The PLLA-HA nanoparticle composite bone substitute developed in this study showed biocompatibility, elasticity, and operability and thus has potential as a novel bone substitute.

Interaction of Poly(l-lysine)/Polysaccharide Complex Nanoparticles with Human Vascular Endothelial Cells.

PubMed

Weber, Dominik; Torger, Bernhard; Richter, Karsten; Nessling, Michelle; Momburg, Frank; Woltmann, Beatrice; Müller, Martin; Schwartz-Albiez, Reinhard

2018-05-23

Angiogenesis plays an important role in both soft and hard tissue regeneration, which can be modulated by therapeutic drugs. If nanoparticles (NP) are used as vectors for drug delivery, they have to encounter endothelial cells (EC) lining the vascular lumen, if applied intravenously. Herein the interaction of unloaded polyelectrolyte complex nanoparticles (PECNP) composed of cationic poly(l-lysine) (PLL) and various anionic polysaccharides with human vascular endothelial cells (HUVEC) was analyzed. In particular PECNP were tested for their cell adhesive properties, their cellular uptake and intracellular localization considering composition and net charge. PECNP may form a platform for both cell coating and drug delivery. PECNP, composed of PLL in combination with the polysaccharides dextran sulfate (DS), cellulose sulfate (CS) or heparin (HEP), either unlabeled or labeled with fluorescein isothiocyanate (FITC) and either with positive or negative net charge were prepared. PECNP were applied to human umbilical cord vein endothelial cells (HUVEC) in both, the volume phase and immobilized phase at model substrates like tissue culture dishes. The attachment of PECNP to the cell surface, their intracellular uptake, and effects on cell proliferation and growth behavior were determined. Immobilized PECNP reduced attachment of HUVEC, most prominently the systems PLL/HEP and PLL/DS. A small percentage of immobilized PECNP was taken up by cells during adhesion. PECNP in the volume phase showed no effect of the net charge sign and only minor effects of the composition on the binding and uptake of PECNP at HUVEC. PECNP were stored in endosomal vesicles in a cumulative manner without apparent further processing. During mitosis, internalized PECNP were almost equally distributed among the dividing cells. Both, in the volume phase and immobilized at the surface, PECNP composed of PLL/HEP and PLL/DS clearly reduced cell proliferation of HUVEC, however without an apparent cytotoxic effect, while PLL/CS composition showed minor impairment. PECNP have an anti-adhesive effect on HUVEC and are taken up by endothelial cells which may negatively influence the proliferation rate of HUVEC. The negative effects were less obvious with the composition PLL/CS. Since uptake and binding for PLL/HEP was more efficient than for PLL/DS, PECNP of PLL/HEP may be used to deliver growth factors to endothelial cells during vascularization of bone reconstitution material, whereas those of PLL/CS may have an advantage for substituting biomimetic bone scaffold material.

Comparative study on in vitro biocompatibility of synthetic octacalcium phosphate and calcium phosphate ceramics used clinically.

PubMed

Morimoto, Shinji; Anada, Takahisa; Honda, Yoshitomo; Suzuki, Osamu

2012-08-01

The present study was designed to investigate the extent to which calcium phosphate bone substitute materials, including osteoconductive octacalcium phosphate (OCP), display cytotoxic and inflammatory responses based on their dissolution in vitro. Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics, which are clinically used, as well as dicalcium phosphate dihydrate (DCPD) and synthesized OCP were compared. The materials were well characterized by chemical analysis, x-ray diffraction and Fourier transform infrared spectroscopy. Calcium and phosphate ion concentrations and the pH of culture media after immersion of the materials were determined. The colony forming rate of Chinese hamster lung fibroblasts was estimated with extraction of the materials. Proliferation of bone marrow stromal ST-2 cells and inflammatory cytokine TNF-α production by THP-1 cells grown on the material-coated plates were examined. The materials had characteristics that corresponded to those reported. DCPD was shown to dissolve the most in the culture media, with a marked increase in phosphate ion concentration and a reduction in pH. ST-2 cells proliferated well on the materials, with the exception of DCPD, which markedly inhibited cellular growth. The colony forming capacity was the lowest on DCPD, while that of the other calcium phosphates was not altered. In contrast, TNF-α was not detected even in cells grown on DCPD, suggesting that calcium phosphate materials are essentially non-inflammatory, while the solubility of the materials can affect osteoblastic and fibroblastic cellular attachment. These results indicate that OCP is biocompatible, which is similar to the materials used clinically, such as HA. Therefore, OCP could be clinically used as a biocompatible bone substitute material.

Mechanobiological simulations of peri-acetabular bone ingrowth: a comparative analysis of cell-phenotype specific and phenomenological algorithms.

PubMed

Mukherjee, Kaushik; Gupta, Sanjay

2017-03-01

Several mechanobiology algorithms have been employed to simulate bone ingrowth around porous coated implants. However, there is a scarcity of quantitative comparison between the efficacies of commonly used mechanoregulatory algorithms. The objectives of this study are: (1) to predict peri-acetabular bone ingrowth using cell-phenotype specific algorithm and to compare these predictions with those obtained using phenomenological algorithm and (2) to investigate the influences of cellular parameters on bone ingrowth. The variation in host bone material property and interfacial micromotion of the implanted pelvis were mapped onto the microscale model of implant-bone interface. An overall variation of 17-88 % in peri-acetabular bone ingrowth was observed. Despite differences in predicted tissue differentiation patterns during the initial period, both the algorithms predicted similar spatial distribution of neo-tissue layer, after attainment of equilibrium. Results indicated that phenomenological algorithm, being computationally faster than the cell-phenotype specific algorithm, might be used to predict peri-prosthetic bone ingrowth. The cell-phenotype specific algorithm, however, was found to be useful in numerically investigating the influence of alterations in cellular activities on bone ingrowth, owing to biologically related factors. Amongst the host of cellular activities, matrix production rate of bone tissue was found to have predominant influence on peri-acetabular bone ingrowth.

Characterization of Silk Fibroin/Chitosan 3D Porous Scaffold and In Vitro Cytology.

PubMed

Zeng, Shuguang; Liu, Lei; Shi, Yong; Qiu, Junqi; Fang, Wei; Rong, Mingdeng; Guo, Zehong; Gao, Wenfeng

2015-01-01

Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF) and chitosan (CS) are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering.

[Neuro-skeletal biology and its importance for clinical osteology].

PubMed

Zofková, I

2012-01-01

Bone remodeling is determined by function of two basic cell forms--bone resorbing osteoclasts and bone formation activating osteoblasts. Both cells are under control of a variety of endogenic and environmental factors, which ensure balance between bone resorption and bone formation. This article reviews the neuro-hormonal factors with osteoanabolic (central isoform of serotonin, melatonin, cannabinoids, beta 1 adrenergic system, oxytocin, ACTH and TSH) or osteocatabolic effects (neuropeptide Y, neuromedin U, beta2 adrenergic system). The dual effects of the beta-adrenergic system, serotonin and leptin are also discussed. The goal of studies focused on neuro-skeletal interaction is to synthesize new molecules, which can modify osteo-anabolic or osteo-catabolic pathways.

Biological properties of solid free form designed ceramic scaffolds with BMP-2: in vitro and in vivo evaluation.

PubMed

Abarrategi, Ander; Moreno-Vicente, Carolina; Martínez-Vázquez, Francisco Javier; Civantos, Ana; Ramos, Viviana; Sanz-Casado, José Vicente; Martínez-Corriá, Ramón; Perera, Fidel Hugo; Mulero, Francisca; Miranda, Pedro; López-Lacomba, José Luís

2012-01-01

Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures.

Biological Properties of Solid Free Form Designed Ceramic Scaffolds with BMP-2: In Vitro and In Vivo Evaluation

PubMed Central

Abarrategi, Ander; Moreno-Vicente, Carolina; Martínez-Vázquez, Francisco Javier; Civantos, Ana; Ramos, Viviana; Sanz-Casado, José Vicente; Martínez-Corriá, Ramón; Perera, Fidel Hugo; Mulero, Francisca; Miranda, Pedro; López-Lacomba, José Luís

2012-01-01

Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures. PMID:22470527

Human mesenchymal stem cells and biomaterials interaction: a promising synergy to improve spine fusion.

PubMed

Barbanti Brodano, G; Mazzoni, E; Tognon, M; Griffoni, C; Manfrini, M

2012-05-01

Spine fusion is the gold standard treatment in degenerative and traumatic spine diseases. The bone regenerative medicine needs (i) in vitro functionally active osteoblasts, and/or (ii) the in vivo induction of the tissue. The bone tissue engineering seems to be a very promising approach for the effectiveness of orthopedic surgical procedures, clinical applications are often hampered by the limited availability of bone allograft or substitutes. New biomaterials have been recently developed for the orthopedic applications. The main characteristics of these scaffolds are the ability to induce the bone tissue formation by generating an appropriate environment for (i) the cell growth and (ii) recruiting precursor bone cells for the proliferation and differentiation. A new prototype of biomaterials known as "bioceramics" may own these features. Bioceramics are bone substitutes mainly composed of calcium and phosphate complex salt derivatives. In this study, the characteristics bioceramics bone substitutes have been tested with human mesenchymal stem cells obtained from the bone marrow of adult orthopedic patients. These cellular models can be employed to characterize in vitro the behavior of different biomaterials, which are used as bone void fillers or three-dimensional scaffolds. Human mesenchymal stem cells in combination with biomaterials seem to be good alternative to the autologous or allogenic bone fusion in spine surgery. The cellular model used in our study is a useful tool for investigating cytocompatibility and biological features of HA-derived scaffolds.

IL-18 Contributes to Bone Cancer Pain by Regulating Glia Cells and Neuron Interaction.

PubMed

Liu, Su; Liu, Yue-Peng; Lv, You; Yao, Jun-Li; Yue, Dong-Mei; Zhang, Mao-Yin; Qi, Dun-Yi; Liu, Gong-Jian

2018-02-01

Glial cell hyperactivity has been proposed to be responsible for chronic pain, however, the mechanisms remain unclear. Interleukin (IL)-18, released from glial cells, has been reported to be involved in neuropathic pain. In this study, we investigated the role of IL-18 in bone cancer pain. Bone cancer pain was mimicked by injecting Walker-256 mammary gland carcinoma cells into the intramedullary space of the tibia in rats. Expression and location of IL-18 and the IL-18 receptor were tested. To investigate the contribution of IL-18 signaling to bone cancer pain, IL-18 binding protein and recombinant IL-18 were used. To investigate the mechanisms of glial cells effects, MK801, N-methyl-D-aspartate (NMDA) receptor inhibitor, and Src kinase-specific inhibitor PP1 were used. Tumor cell implantation (TCI) treatment increased expression of IL-18 and IL-18 receptor in spinal cord. The time course of IL-18 upregulation was correlated with TCI-induced pain behaviors. Blocking the IL-18 signaling pathway prevented and reversed bone cancer-related pain behaviors. Meanwhile, blocking IL-18 signaling also suppressed TCI-induced glial cell hyperactivity, as well as activation of GluN2B and subsequent Ca 2+ -dependent signaling. Spinal administration of recombinant IL-18 in naive rat induced significant mechanical allodynia, as well as GluN2B activation. However, intrathecal injection of MK801 failed to suppress recombinant IL-18-induced GluN2B phosphorylation, whereas Src kinase inhibitor PP1 significantly inhibited IL-18-induced GluN2B activation. IL-18-mediated glial-glia and glial-neuron interaction may facilitate bone cancer pain. Blocking IL-18 signaling may effectively prevent and/or suppress bone cancer pain. IL-18 signaling may be a new target for cancer pain therapy. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

PubMed

Luo, Zuyuan; Deng, Yi; Zhang, Ranran; Wang, Mengke; Bai, Yanjie; Zhao, Qiang; Lyu, Yalin; Wei, Jie; Wei, Shicheng

2015-07-01

Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500μg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of Emulsifying Wax/GMO Nanoparticles and Evaluation as a Delivery System for Repurposing Simvastatin in Bone Regeneration.

PubMed

Eskinazi-Budge, Aaron; Manickavasagam, Dharani; Czech, Tori; Novak, Kimberly; Kunzler, James; Oyewumi, Moses O

2018-05-30

Simvastatin (Sim) is a widely known drug in the treatment of hyperlipidemia that has attracted so much attention in bone regeneration based on its potential osteoanabolic effect. However, repurposing of Sim in bone regeneration will require suitable delivery systems that can negate undesirable off-target/side effects. In this study, we have investigated a new lipid nanoparticle (NP) platform that was fabricated using a binary blend of emulsifying wax (Ewax) and glyceryl monooleate (GMO). Using the binary matrix materials, NPs loaded with Sim (0-500 µg/mL) were prepared and showed an average particle size of about 150 nm. NP size stability was dependent on Sim concentration loaded in NPs. The suitability of NPs prepared with the binary matrix materials in Sim delivery for potential application in bone regeneration was supported by biocompatibility in pre-osteoclastic and pre-osteoblastic cells. Additional data demonstrated that biofunctional Sim was released from NPs that facilitated differentiation of osteoblasts (cells that form bones) while inhibiting differentiation of osteoclasts (cells that resorb bones). The overall work demonstrated the preparation of NPs from Ewax/GMO blends and characterization to ascertain potential suitability in Sim delivery for bone regeneration. Additional studies on osteoblast and osteoclast functions are warranted to fully evaluate the efficacy simvastatin-loaded Ewax/GMO NPs using in-vitro and in-vivo approaches.

Pre-clinical characterization of tissue engineering constructs for bone and cartilage regeneration

PubMed Central

Trachtenberg, Jordan E.; Vo, Tiffany N.; Mikos, Antonios G.

2014-01-01

Pre-clinical animal models play a crucial role in the translation of biomedical technologies from the bench top to the bedside. However, there is a need for improved techniques to evaluate implanted biomaterials within the host, including consideration of the care and ethics associated with animal studies, as well as the evaluation of host tissue repair in a clinically relevant manner. This review discusses non-invasive, quantitative, and real-time techniques for evaluating host-materials interactions, quality and rate of neotissue formation, and functional outcomes of implanted biomaterials for bone and cartilage tissue engineering. Specifically, a comparison will be presented for pre-clinical animal models, histological scoring systems, and non-invasive imaging modalities. Additionally, novel technologies to track delivered cells and growth factors will be discussed, including methods to directly correlate their release with tissue growth. PMID:25319726

Pre-clinical characterization of tissue engineering constructs for bone and cartilage regeneration.

PubMed

Trachtenberg, Jordan E; Vo, Tiffany N; Mikos, Antonios G

2015-03-01

Pre-clinical animal models play a crucial role in the translation of biomedical technologies from the bench top to the bedside. However, there is a need for improved techniques to evaluate implanted biomaterials within the host, including consideration of the care and ethics associated with animal studies, as well as the evaluation of host tissue repair in a clinically relevant manner. This review discusses non-invasive, quantitative, and real-time techniques for evaluating host-materials interactions, quality and rate of neotissue formation, and functional outcomes of implanted biomaterials for bone and cartilage tissue engineering. Specifically, a comparison will be presented for pre-clinical animal models, histological scoring systems, and non-invasive imaging modalities. Additionally, novel technologies to track delivered cells and growth factors will be discussed, including methods to directly correlate their release with tissue growth.

Multiple Perforations of the Sinus Floor During Maxillary Sinus Floor Augmentation to Provide Access to the Bone Marrow Space: A Technical Report.

PubMed

Ulm, Christian; Bertl, Kristina; Strbac, Georg D; Esfandeyari, Azadeh; Stavropoulos, Andreas; Zechner, Werner

2017-12-01

Sinus floor augmentation is a routinely used surgical technique for increasing the bone height/volume of the atrophic posterior maxilla. Optimal integration of the implanted augmentation material within the newly formed bone will-at least partly-depend on adequate vascularization to ensure sufficient recruitment of osteoblast and osteoclast precursor cells. The present technical note describes a modification intended to facilitate increased blood inflow into the augmented space. After preparation of the lateral window and elevation of the Schneiderian membrane, the cortical bone of the sinus floor is perforated several times either by using a piezoelectric device or a microsurgical handpiece with the corresponding tip or bur; these perforations should extend into the trabecular bone. The experiences with this modified technique after 12 patients are presented and discussed. It is expected that by means of this relatively simple technique, increased blood and cell inflow into the augmented space is achieved. This may, in turn, enhance new bone formation and improve the integration of the augmentation material.

Dasatinib inhibits both osteoclast activation and prostate cancer PC-3 cell-induced osteoclast formation

PubMed Central

Araujo, John C.; Poblenz, Ann; Corn, Paul G.; Parikh, Nila U.; Starbuck, Michael W.; Thompson, Jerry T.; Lee, Francis; Logothetis, Christopher J.; Darnay, Bryant G.

2013-01-01

Purpose Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Results Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC50 of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. Experimental design We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Conclusion Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases. PMID:19855158

Enhanced bone screw fixation with biodegradable bone cement in osteoporotic bone model.

PubMed

Juvonen, Tiina; Koistinen, Arto; Kröger, Heikki; Lappalainen, Reijo

2012-09-27

The purpose of this study was to study the potential of novel biodegradable PCL bone cement to improve bone screw fixation strength in osteoporotic bone. The biomechanical properties of bone cement (ε-polycaprolactone, PCL) and fixation strength were studied using biomechanical tests and bone screws fixed in an osteoporotic bone model. Removal torques and pullout strengths were assessed for cortical, self-tapping, and cancellous screws inserted in the osteoporotic bone model (polyurethane foam blocks with polycarbonate plate) with and without PCL bone cement. Open cell and cellular rigid foam blocks with a density of 0.12 g/cm3 were used in this model. Removal torques were significantly (more than six-fold) improved with bone cement for cancellous screws. Furthermore, the bone cement improved pullout strengths three to 12 times over depending on the screw and model material. Biodegradable bone cement turned out to be a very potential material to stabilize screw fixation in osteoporotic bone. The results warrant further research before safe clinical use, especially to clarify clinically relevant factors using real osteoporotic bone under human body conditions and dynamic fatigue testing for long-term performance.

Study of Osteoclast Adhesion to Cortical Bone Surfaces: A Correlative Microscopy Approach for Concomitant Imaging of Cellular Dynamics and Surface Modifications

PubMed Central

2015-01-01

Bone remodeling relies on the coordinated functioning of osteoblasts, bone-forming cells, and osteoclasts, bone-resorbing cells. The effects of specific chemical and physical bone features on the osteoclast adhesive apparatus, the sealing zone ring, and their relation to resorption functionality are still not well-understood. We designed and implemented a correlative imaging method that enables monitoring of the same area of bone surface by time-lapse light microscopy, electron microscopy, and atomic force microscopy before, during, and after exposure to osteoclasts. We show that sealing zone rings preferentially develop around surface protrusions, with lateral dimensions of several micrometers, and ∼1 μm height. Direct overlay of sealing zone rings onto resorption pits on the bone surface shows that the rings adapt to pit morphology. The correlative procedure presented here is noninvasive and performed under ambient conditions, without the need for sample labeling. It can potentially be applied to study various aspects of cell-matrix interactions. PMID:26682493

CD44-mediated hyaluronan binding marks proliferating hematopoietic progenitor cells and promotes bone marrow engraftment

PubMed Central

Lee-Sayer, Sally S. M.; Dougan, Meghan N.; Cooper, Jesse; Sanderson, Leslie; Dosanjh, Manisha; Maxwell, Christopher A.

2018-01-01

CD44 is a widely expressed cell adhesion molecule that binds to the extracellular matrix component, hyaluronan. However, this interaction is not constitutive in most immune cells at steady state, as the ability of CD44 to engage hyaluronan is highly regulated. While activated T cells and macrophages gain the ability to bind hyaluronan by CD44, the status in other immune cells is less studied. Here we found a percentage of murine eosinophils, natural killer and natural killer T cells were capable of interacting with hyaluronan at steady state. To further investigate the consequences of hyaluronan binding by CD44 in the hematopoietic system, point mutations of CD44 that either cannot bind hyaluronan (LOF-CD44) or have an increased affinity for hyaluronan (GOF-CD44) were expressed in CD44-deficient bone marrow. Competitive bone marrow reconstitution of irradiated mice revealed an early preference for GOF-CD44 over WT-CD44 expressing cells, and for WT-CD44 over LOF-CD44 expressing cells, in the hematopoietic progenitor cell compartment. The advantage of the hyaluronan-binding cells was observed in the hematopoietic stem and progenitor populations, and was maintained throughout the immune system. Hematopoietic stem cells bound minimal hyaluronan at steady state, and this was increased when the cells were induced to proliferate whereas multipotent progenitors had an increased ability to bind hyaluronan at steady state. In vitro, the addition of hyaluronan promoted their proliferation. Thus, proliferating hematopoietic progenitors bind hyaluronan, and hyaluronan binding cells have a striking competitive advantage in bone marrow engraftment. PMID:29684048

Bone Quest - A Space-Based Science and Health Education Unit

NASA Technical Reports Server (NTRS)

Smith, Scott M.; David-Street, Janis E.; Abrams, Steve A.

2000-01-01

This proposal addresses the need for effective and innovative science and health education materials that focus on space bone biology and its implications for bone health on Earth. The focus of these materials, bone biology and health, will increase science knowledge as well as health awareness. Current investigations of the bone loss observed after long-duration space missions provide a link between studies of bone health in space, and studies of osteoporosis, a disease characterized by bone loss and progressive skeletal weakness. The overall goal of this project is to design and develop web-based and print-based materials for high school science students, that will address the following: a) knowledge of normal bone biology and bone biology in a microgravity environment; b) knowledge of osteoporosis; c) knowledge of treatment modalities for space- and Earth-based bone loss; and d} bone-related nutrition knowledge and behavior. To this end, we propose to design and develop a Bone Biology Tutorial which will instruct students about normal bone biology, bone biology in a microgravity environment, osteoporosis - its definition, detection, risk factors, and prevention, treatment modalities for space- and Earth-based bone loss, and the importance of nutrition in bone health. Particular emphasis will be placed on current trends in . adolescent nutrition, and their relationships to bone health. Additionally, we propose to design and develop two interactive nutrition/health ' education activities that will allow students to apply the information provided in the Bone Biology Tutorial. In the first, students will apply constructs provided in the Bone Biology Tutorial to design "Bone Health Plans" for space travelers.

Journey into Bone Models: A Review

PubMed Central

Scheinpflug, Julia; Pfeiffenberger, Moritz; Damerau, Alexandra; Schwarz, Franziska; Textor, Martin; Lang, Annemarie

2018-01-01

Bone is a complex tissue with a variety of functions, such as providing mechanical stability for locomotion, protection of the inner organs, mineral homeostasis and haematopoiesis. To fulfil these diverse roles in the human body, bone consists of a multitude of different cells and an extracellular matrix that is mechanically stable, yet flexible at the same time. Unlike most tissues, bone is under constant renewal facilitated by a coordinated interaction of bone-forming and bone-resorbing cells. It is thus challenging to recreate bone in its complexity in vitro and most current models rather focus on certain aspects of bone biology that are of relevance for the research question addressed. In addition, animal models are still regarded as the gold-standard in the context of bone biology and pathology, especially for the development of novel treatment strategies. However, species-specific differences impede the translation of findings from animal models to humans. The current review summarizes and discusses the latest developments in bone tissue engineering and organoid culture including suitable cell sources, extracellular matrices and microfluidic bioreactor systems. With available technology in mind, a best possible bone model will be hypothesized. Furthermore, the future need and application of such a complex model will be discussed. PMID:29748516

Journey into Bone Models: A Review.

PubMed

Scheinpflug, Julia; Pfeiffenberger, Moritz; Damerau, Alexandra; Schwarz, Franziska; Textor, Martin; Lang, Annemarie; Schulze, Frank

2018-05-10

Bone is a complex tissue with a variety of functions, such as providing mechanical stability for locomotion, protection of the inner organs, mineral homeostasis and haematopoiesis. To fulfil these diverse roles in the human body, bone consists of a multitude of different cells and an extracellular matrix that is mechanically stable, yet flexible at the same time. Unlike most tissues, bone is under constant renewal facilitated by a coordinated interaction of bone-forming and bone-resorbing cells. It is thus challenging to recreate bone in its complexity in vitro and most current models rather focus on certain aspects of bone biology that are of relevance for the research question addressed. In addition, animal models are still regarded as the gold-standard in the context of bone biology and pathology, especially for the development of novel treatment strategies. However, species-specific differences impede the translation of findings from animal models to humans. The current review summarizes and discusses the latest developments in bone tissue engineering and organoid culture including suitable cell sources, extracellular matrices and microfluidic bioreactor systems. With available technology in mind, a best possible bone model will be hypothesized. Furthermore, the future need and application of such a complex model will be discussed.

Macrophage involvement affects matrix stiffness-related influences on cell osteogenesis under three-dimensional culture conditions.

PubMed

He, Xiao-Tao; Wu, Rui-Xin; Xu, Xin-Yue; Wang, Jia; Yin, Yuan; Chen, Fa-Ming

2018-04-15

Accumulating evidence indicates that the physicochemical properties of biomaterials exert profound influences on stem cell fate decisions. However, matrix-based regulation selected through in vitro analyses based on a given cell population do not genuinely reflect the in vivo conditions, in which multiple cell types are involved and interact dynamically. This study constitutes the first investigation of how macrophages (Mφs) in stiffness-tunable transglutaminase cross-linked gelatin (TG-gel) affect the osteogenesis of bone marrow-derived mesenchymal stem cells (BMMSCs). When a single cell type was cultured, low-stiffness TG-gels promoted BMMSC proliferation, whereas high-stiffness TG-gels supported cell osteogenic differentiation. However, Mφs in high-stiffness TG-gels were more likely to polarize toward the pro-inflammatory M1 phenotype. Using either conditioned medium (CM)-based incubation or Transwell-based co-culture, we found that Mφs encapsulated in the low-stiffness matrix exerted a positive effect on the osteogenesis of co-cultured BMMSCs. Conversely, Mφs in high-stiffness TG-gels negatively affected cell osteogenic differentiation. When both cell types were cultured in the same TG-gel type and placed into the Transwell system, the stiffness-related influences of Mφs on BMMSCs were significantly altered; both the low- and high-stiffness matrix induced similar levels of BMMSC osteogenesis. Although the best material parameter for synergistically affecting Mφs and BMMSCs remains unknown, our data suggest that Mφ involvement in the co-culture system alters previously identified material-related influences on BMMSCs, such as matrix stiffness-related effects, which were identified based on a culture system involving a single cell type. Such Mφ-stem cell interactions should be considered when establishing proper matrix parameter-associated cell regulation in the development of biomimetic biomaterials for regenerative applications. The substrate stiffness of a scaffold plays critical roles in modulating both reparative cells, such as mesenchymal stem cells (MSCs), and immune cells, such as macrophages (Mφs). Although the influences of material stiffness on either Mφs or MSCs, have been extensively described, how the two cell types respond to matrix cues to dynamically affect each other in a three-dimensional (3D) biosystem remains largely unknown. Here, we report our findings that, in a platform wherein Mφs and bone marrow-derived MSCs coexist, matrix stiffness can influence stem cell fate through both direct matrix-associated regulation and indirect Mφ-based modulation. Our data support future studies of the MSC-Mφ-matrix interplay in the 3D context to optimize matrix parameters for the development of the next biomaterial. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Is trabecular bone permeability governed by molecular ordering-induced fluid viscosity gain? Arguments from re-evaluation of experimental data in the framework of homogenization theory.

PubMed

Abdalrahman, T; Scheiner, S; Hellmich, C

2015-01-21

It is generally agreed on that trabecular bone permeability, a physiologically important quantity, is governed by the material׳s (vascular or intertrabecular) porosity as well as by the viscosity of the pore-filling fluids. Still, there is less agreement on how these two key factors govern bone permeability. In order to shed more light onto this somewhat open issue, we here develop a random homogenization scheme for upscaling Poiseuille flow in the vascular porosity, up to Darcy-type permeability of the overall porous medium "trabecular bone". The underlying representative volume element of the macroscopic bone material contains two types of phases: a spherical, impermeable extracellular bone matrix phase interacts with interpenetrating cylindrical pore channel phases that are oriented in all different space directions. This type of interaction is modeled by means of a self-consistent homogenization scheme. While the permeability of the bone matrix equals to zero, the permeability of the pore phase is found through expressing the classical Hagen-Poiseuille law for laminar flow in the format of a "micro-Darcy law". The upscaling scheme contains pore size and porosity as geometrical input variables; however, they can be related to each other, based on well-known relations between porosity and specific bone surface. As two key results, validated through comprehensive experimental data, it appears (i) that the famous Kozeny-Carman constant (which relates bone permeability to the cube of the porosity, the square of the specific surface, as well as to the bone fluid viscosity) needs to be replaced by an again porosity-dependent rational function, and (ii) that the overall bone permeability is strongly affected by the pore fluid viscosity, which, in case of polarized fluids, is strongly increased due to the presence of electrically charged pore walls. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Molecular and Cellular Events That Take Place during Craniofacial Distraction Osteogenesis

PubMed Central

Rachmiel, Adi

2014-01-01

Summary: Gradual bone lengthening using distraction osteogenesis principles is the gold standard for the treatment of hypoplastic facial bones. However, the long treatment time is a major disadvantage of the lengthening procedures. The aim of this study is to review the current literature and summarize the cellular and molecular events occurring during membranous craniofacial distraction osteogenesis. Mechanical stimulation by distraction induces biological responses of skeletal regeneration that is accomplished by a cascade of biological processes that may include differentiation of pluripotential tissue, angiogenesis, osteogenesis, mineralization, and remodeling. There are complex interactions between bone-forming osteoblasts and other cells present within the bone microenvironment, particularly vascular endothelial cells that may be pivotal members of a complex interactive communication network in bone. Studies have implicated number of cytokines that are intimately involved in the regulation of bone synthesis and turnover. The gene regulation of numerous cytokines (transforming growth factor-β, bone morphogenetic proteins, insulin-like growth factor-1, and fibroblast growth factor-2) and extracellular matrix proteins (osteonectin, osteopontin) during distraction osteogenesis has been best characterized and discussed. Understanding the biomolecular mechanisms that mediate membranous distraction osteogenesis may guide the development of targeted strategies designed to improve distraction osteogenesis and accelerate bone regeneration that may lead to shorten the treatment duration. PMID:25289295

Antioxidant and bone repair properties of quercetin-functionalized hydroxyapatite: An in vitro osteoblast-osteoclast-endothelial cell co-culture study.

PubMed

Forte, Lucia; Torricelli, Paola; Boanini, Elisa; Gazzano, Massimo; Rubini, Katia; Fini, Milena; Bigi, Adriana

2016-03-01

Quercetin (3,3',4',5,7-pentahydroxy-flavone) is a flavonoid known for its pharmacological activities, which include antioxidant and anti-inflammatory properties, as well as possible beneficial action on diseases involving bone loss. In this work, we explored the possibility to functionalize hydroxyapatite (HA) with quercetin in order to obtain new materials for bone repair through local administration of the flavonoid. HA was synthesized in presence of different concentrations of quercetin according to two different procedures: direct synthesis and phase transition from monetite. Direct synthesis lead to composite nanocrystals containing up to 3.1 wt% quercetin, which provokes a reduction of the crystals mean dimensions and of the length of the coherently scattering domains. Synthesis conditions provoke a partial oxidation of quercetin and, as a consequence, a significant reduction of its radical scavenging activity (RSA). On the other hand, synthesis through phase transition yields samples containing up to 1.3 wt% of quercetin incorporated into hydroxyapatite, with minor structural modifications, which exhibit relevant anti-oxidant activities, as testified by their high RSA levels, (slightly lower than that of pure quercetin). The biological response to these materials was tested using an innovative triculture model involving osteoblast, osteoclast and endothelial cells, in order to mimic bone microenvironment. The results show that the presence of quercetin in the composite materials enhances human osteoblast-like MG63 proliferation and differentiation, whereas it downregulates osteoclastogenesis of osteoclast precursors 2T-110, and supports proliferation and differentiation of human umbilical vein endothelial cells (HUVEC). The pharmacological activities of the flavonoid quercetin include anti-oxidant and antiinflammatory properties, as well as capability to prevent bone loss. In this paper, we demonstrate that it is possible to synthesize hydroxyapatite functionalized with different amounts of quercetin and obtain new composite materials which display both the good bioactivity of the inorganic phase and the therapeutic properties of the flavonoid. The innovative in vitro model developed in this study, which involves co-culture of osteoblast, osteoclast and endothelial cells, allows to state that the new materials exert a beneficial action onto bone repair microenvironment, stimulating osteoblast proliferation and activity, downregulating osteoclastogenesis, and supporting microangiogenetic processes necessary for new bone formation. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Nuclear microprobe imaging of gallium nitrate in cancer cells

NASA Astrophysics Data System (ADS)

Ortega, Richard; Suda, Asami; Devès, Guillaume

2003-09-01

Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

Fluid flow in the osteocyte mechanical environment: a fluid-structure interaction approach.

PubMed

Verbruggen, Stefaan W; Vaughan, Ted J; McNamara, Laoise M

2014-01-01

Osteocytes are believed to be the primary sensor of mechanical stimuli in bone, which orchestrate osteoblasts and osteoclasts to adapt bone structure and composition to meet physiological loading demands. Experimental studies to quantify the mechanical environment surrounding bone cells are challenging, and as such, computational and theoretical approaches have modelled either the solid or fluid environment of osteocytes to predict how these cells are stimulated in vivo. Osteocytes are an elastic cellular structure that deforms in response to the external fluid flow imposed by mechanical loading. This represents a most challenging multi-physics problem in which fluid and solid domains interact, and as such, no previous study has accounted for this complex behaviour. The objective of this study is to employ fluid-structure interaction (FSI) modelling to investigate the complex mechanical environment of osteocytes in vivo. Fluorescent staining of osteocytes was performed in order to visualise their native environment and develop geometrically accurate models of the osteocyte in vivo. By simulating loading levels representative of vigorous physiological activity ([Formula: see text] compression and 300 Pa pressure gradient), we predict average interstitial fluid velocities [Formula: see text] and average maximum shear stresses [Formula: see text] surrounding osteocytes in vivo. Interestingly, these values occur in the canaliculi around the osteocyte cell processes and are within the range of stimuli known to stimulate osteogenic responses by osteoblastic cells in vitro. Significantly our results suggest that the greatest mechanical stimulation of the osteocyte occurs in the cell processes, which, cell culture studies have indicated, is the most mechanosensitive area of the cell. These are the first computational FSI models to simulate the complex multi-physics mechanical environment of osteocyte in vivo and provide a deeper understanding of bone mechanobiology.

3D printing of hybrid biomaterials for bone tissue engineering: Calcium-polyphosphate microparticles encapsulated by polycaprolactone.

PubMed

Neufurth, Meik; Wang, Xiaohong; Wang, Shunfeng; Steffen, Renate; Ackermann, Maximilian; Haep, Natalie D; Schröder, Heinz C; Müller, Werner E G

2017-12-01

Here we describe the formulation of a morphogenetically active bio-ink consisting of amorphous microparticles (MP) prepared from Ca 2+ and the physiological inorganic polymer, polyphosphate (polyP). Those MP had been fortified by mixing with poly-ε-caprolactone (PCL) to allow 3D-bioprinting. The resulting granular PCL/Ca-polyP-MP hybrid material, liquefied by short-time heating to 100 °C, was used for the 3D-printing of tissue-like scaffolds formed by strands with a thickness of 400 µm and a stacked architecture leaving ≈0.5 mm 2 -sized open holes enabling cell migration. The printed composite scaffold turned out to combine suitable biomechanical properties (Young's modulus of 1.60 ± 0.1 GPa; Martens hardness of 153 ± 28 MPa), matching those of cortical and trabecular bone, with morphogenetic activity. This scaffold was capable of attracting and promoting the growth of human bone-related SaOS-2 cells as demonstrated by staining for cell viability (Calcein AM), cell density (DRAQ5) and SEM studies. Furthermore, the hybrid material was demonstrated to upregulate the steady-state-expression of the cell migration-inducing chemokine SDF-1α. EDX analysis and FTIR measurements revealed the presence of hydroxyapatite in the mineral deposits formed on the scaffold surface. Based on the results we conclude that granular PCL/Ca-polyP-MP hybrid material is suitable for the fabrication of bioprintable scaffold which comprises not only biomechanical stability but also morphogenetic potential. In present-day regenerative engineering efforts, biomaterial- and cell-based strategies are proposed that meet the required functional and spatial characteristics and variations, especially in the transition regions between soft (cartilage, tendon or ligament) and hard (bone) tissues. In a biomimetic approach we succeeded to fabricate amorphous Ca-polyP nanoparticles/microparticles which are highly biocompatible. Together with polycaprolactone (PCL), polyP can be bio-printed. This hybrid material attracts the cells, as documented optically as well as by a gene-expression studies. Since PCL is already a FDA-approved organic and inert polymer and polyP a physiological biologically active component this new bio-hybrid material has the potential to restore physiological functions, including bone remodelling and regeneration if used as implant. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Basement membrane of mouse bone marrow sinusoids shows distinctive structure and proteoglycan composition: a high resolution ultrastructural study.

PubMed

Inoue, S; Osmond, D G

2001-11-01

Venous sinusoids in bone marrow are the site of a large-scale traffic of cells between the extravascular hemopoietic compartment and the blood stream. The wall of the sinusoids consists solely of a basement membrane interposed between a layer of endothelial cells and an incomplete covering of adventitial cells. To examine its possible structural specialization, the basement membrane of bone marrow sinusoids has now been examined by high resolution electron microscopy of perfusion-fixed mouse bone marrow. The basement membrane layer was discontinuous, consisting of irregular masses of amorphous material within a uniform 60-nm-wide space between apposing endothelial cells and adventitial cell processes. At maximal magnifications, the material was resolved as a random arrangement of components lacking the "cord network" formation seen in basement membranes elsewhere. Individual components exhibited distinctive ultrastructural features whose molecular identity has previously been established. By these morphological criteria, the basement membrane contained unusually abundant chondroitin sulfate proteoglycan (CSPG) revealed by 3-nm-wide "double tracks," and moderate amounts of both laminin as dense irregular coils and type IV collagen as 1-1.5-nm-wide filaments, together with less conspicuous amounts of amyloid P forming pentagonal frames. In contrast, 4.5-5-nm-wide "double tracks" characteristic of heparan sulfate proteoglycan (HSPG) were absent. The findings demonstrate that, in comparison with "typical" basement membranes in other tissues, the bone marrow sinusoidal basement membrane is uniquely specialized in several respects. Its discontinuous nature, lack of network organization, and absence of HSPG, a molecule that normally helps to maintain membrane integrity, may facilitate disassembly and reassembly of basement membrane material in concert with movements of adventitial cell processes as maturing hemopoietic cells pass through the sinusoidal wall: the exceptionally large quantity of CSPG may represent a reservoir of CD44 receptor for use in hemopoiesis. Copyright 2001 Wiley-Liss, Inc.

Steps in Prostate Cancer Progression that lead to Bone Metastasis

PubMed Central

Jin, Jung-Kang; Dayyani, Farshid; Gallick, Gary E.

2011-01-01

Prostate cancer is a complex disease in which metastasis to the bone is the main cause of death. Initial stages of metastasis are generally similar to those for most solid tumors; however, the mechanisms that underlie the homing of prostate tumor cells to the bone remain incompletely understood. Prostate cancer bone metastasis is also a microenvironment-driven disease, involving bi-directional interactions between the tumor and the bone microenvironment. In this review, we discuss the current understanding of the biologic processes and regulatory factors involved in the metastasis of prostate cancer cells, and their specific properties that promote growth in bone. Although many of these processes still need to be fully elucidated, a better understanding of the complex tumor/microenvironment interplay is slowly leading to more effective therapies for patients with prostate cancer bone metastases. PMID:21365645

Bioactive hydrogel-nanosilica hybrid materials: a potential injectable scaffold for bone tissue engineering.

PubMed

Lewandowska-Łańcucka, Joanna; Fiejdasz, Sylwia; Rodzik, Łucja; Kozieł, Marcin; Nowakowska, Maria

2015-02-10

Novel bioactive organic-inorganic hybrid materials that can serve as injectable hydrogel systems for bone tissue regeneration were obtained. The silica nanoparticles (SiNP) prepared in situ by the Stöber method were dispersed in collagen, collagen-chitosan or chitosan sols, which were then subsequently crosslinked. Laser scanning confocal microscopy studies, in which fluorescent SiNP were applied, and SEM images indicated that the nanosilica particles were distributed in the whole volume of the hydrogel matrix. In vitro studies on fibroblast cell viability indicated that the hybrid materials are biocompatible. The silica nanoparticles dispersed in the biopolymer matrix had a positive effect on cell viability. Studies on the mineralization process under simulated body fluid (SBF) conditions confirmed the bioactivity of prepared materials. SEM images revealed mineral phase formation in the majority of the hybrid materials developed. EDS analysis indicated that these mineral phases are mainly composed of calcium and phosphorus. The XRD studies confirmed that mineral phases formed during SBF incubation of hybrid materials based on collagen are bone-like apatite minerals. The silica nanoparticles added to the hydrogel at the stage of synthesis induced the occurrence of mineralization. This process occurs not only at the surface of the material but in its entire volume, which is important for the preparation of scaffolds for bone tissue engineering. The ability of these materials to undergo in situ gelation under physiological temperature and their bioactivity as well as biocompatibility make them interesting candidates for bioactive injectable systems.

TCP is hardly resorbed and not osteoconductive in a non-loading calvarial model.

PubMed

Handschel, Jörg; Wiesmann, Hans Peter; Stratmann, Udo; Kleinheinz, Johannes; Meyer, Ulrich; Joos, Ulrich

2002-04-01

Tricalciumphosphate (TCP) has been used as a ceramic bone substitute material in the orthopedic field as well as in craniofacial surgery. Some controversies exist concerning the osteoconductive potential of this material in different implantation sites. This study was designed to evaluate the biological response of calvarial bone towards TCP granules under non-loading conditions to assess the potential of TCP as a biodegredable and osteoconductive bone substitue material for the cranial vault. Full-thickness non-critical size defects were made bilaterally in the calvaria of 21 adult Wistar rats. One side was filled by TCP granules, the contralateral side was left empty and used as a control. Animals were sacrified in defined time intervals up to 6 months. Bone regeneration was analyzed with special respect toward the micromorphological and microanalytical features of the material-bone interaction by electron microscopy and electron diffraction analysis. Histologic examination revealed no TCP degradation even after 6 months of implantation. In contrast, a nearly complete bone regeneration of control defects was found after 6 months. At all times TCP was surrounded by a thin fibrous layer without presence of osteoblasts and features of regular mineralization. As far as degradation and substitution are concerned, TCP is a less favourable material tinder conditions of non-loading.

STATs and macrophage fusion.

PubMed

Miyamoto, Takeshi

2013-07-01

Macrophages play a pivotal role in host defense against multiple foreign materials such as bacteria, parasites and artificial devices. Some macrophage lineage cells, namely osteoclasts and foreign body giant cells (FBGCs), form multi-nuclear giant cells by the cell-cell fusion of mono-nuclear cells. Osteoclasts are bone-resorbing cells, and are formed in the presence of RANKL on the surface of bones, while FBGCs are formed in the presence of IL-4 or IL-13 on foreign materials such as artificial joints, catheters and parasites. Recently, fusiogenic mechanisms and the molecules required for the cell-cell fusion of these macrophage lineage cells were, at least in part, clarified. Dendritic cell specific transmembrane protein (DC-STAMP) and osteoclast stimulatory transmembrane protein (OC-STAMP), both of which comprise seven transmembrane domains, are required for both osteoclast and FBGC cell-cell fusion. STAT6 was demonstrated to be required for the cell-cell fusion of FBGCs but not osteoclasts. In this review, advances in macrophage cell-cell fusion are discussed.

Novel Insights into the Relationship between Diabetes and Osteoporosis

PubMed Central

de Paula, Francisco J. A.; Horowitz, Mark C.; Rosen, Clifford J.

2012-01-01

Only three decades ago adipose tissue was considered inert with little relationship to insulin resistance. Similarly bone has long been thought purely in its structural context. In the last decade, emerging evidence has revealed important endocrine roles for both bone and adipose tissue. The interaction between these two tissues is remarkable. Bone marrow mesenchymal stem cells give rise to both osteoblasts and adipocytes. Leptin and adiponectin, two adipokines secreted by fat tissue, control energy homeostasis, but also have complex actions on the skeleton. In turn, the activities of bone cells are not limited to their bone remodeling activities, but also to modulation of adipose sensitivity and insulin secretion. This review will discuss these new insights linking bone remodeling to the control of fat metabolism and the association between diabetes mellitus and osteoporosis. PMID:20938995

Bioactive scaffold for bone tissue engineering: An in vivo study

NASA Astrophysics Data System (ADS)

Livingston, Treena Lynne

Massive bone loss of the proximal femur is a common problem in revision cases of total hip implants. Allograft is typically used to reconstruct the site for insertion of the new prosthesis. However, for long term fixation and function, it is desirable that the allograft becomes fully replaced by bone tissue and aids in the regeneration of bone to that site. However, allograft use is typically associated with delayed incorporation and poor remodeling. Due to these profound limitations, alternative approaches are needed. Tissue engineering is an attractive approach to designing improved graft materials. By combining osteogenic activity with a resorbable scaffold, bone formation can be stimulated while providing structure and stability to the limb during incorporation and remodeling of the scaffold. Porous, surface modified bioactive ceramic scaffolds (pSMC) have been developed which stimulate the expression of the osteoblastic phenotype and production of bone-like tissue in vitro. The scaffold and two tissue-engineered constructs, osteoprogenitor cells seeded onto scaffolds or cells expanded in culture to form bone tissue on the scaffolds prior to implantation, were investigated in a long bone defect model. The rate of incorporation was assessed. Both tissue-engineered constructs stimulated bone formation and comparable repair at 2 weeks. In a rat femoral window defect model, bone formation increased over time for all groups in concert with scaffold resorption, leading to a 40% increase in bone and 40% reduction of the scaffold in the defect by 12 weeks. Both tissue-engineered constructs enhanced the rate of mechanical repair of long bones due to better bony union with the host cortex. Long bones treated with tissue engineered constructs demonstrated a return in normal torsional properties by 4 weeks as compared to 12 weeks for long bones treated with pSMC. Culture expansion of cells to produce bone tissue in vitro did not accelerate incorporation over the treatment with cells seeded at the time of surgery. Porous, surface modified bioactive ceramic is a promising scaffold material for tissue-engineered bone repair. Bone formation and scaffold resorption act in concert for maintenance and improvement of the structural properties of the long bones over time. As determined histomorphometrically and mechanically, the rate of incorporation of the scaffold was enhanced with the tissue-engineered constructs.

Physiology of Mechanotransduction: How Do Muscle and Bone "Talk" to One Another?

PubMed

Isaacson, Janalee; Brotto, Marco

2014-06-01

The complexity of cell interactions with their microenvironment and their ability to communicate at the autocrine, paracrine, and endocrine levels has gradually but significantly evolved in the last three decades. The musculoskeletal system has been historically recognized to be governed by a relationship of proximity and function, chiefly dictated by mechanical forces and the work of gravity itself. In this review article, we first provide a historical overview of the biomechanical theory of bone- muscle interactions. Next, we expand to detail the significant evolution in our understanding of the function of bones and muscles as secretory organs. Then, we review and discuss new evidence in support of a biochemical interaction between these two tissues. We then propose that these two models of interaction are complementary and intertwined providing for a new frontier for the investigation of how bone-muscle cross talk could be fully explored for the targeting of new therapies for musculoskeletal diseases, particularly the twin conditions of aging, osteoporosis and sarcopenia. In the last section, we explore the bone-muscle cross talk in the context of their interactions with other tissues and the global impact of these multi-tissue interactions on chronic diseases.

Coordinated transcriptional regulation of bone homeostasis by Ebf1 and Zfp521 in both mesenchymal and hematopoietic lineages

PubMed Central

Kiviranta, Riku; Yamana, Kei; Saito, Hiroaki; Ho, Daniel K.; Laine, Julius; Tarkkonen, Kati; Nieminen-Pihala, Vappu; Hesse, Eric; Correa, Diego; Määttä, Jorma; Tessarollo, Lino; Rosen, Evan D.; Horne, William C.; Jenkins, Nancy A.; Copeland, Neal G.; Warming, Soren

2013-01-01

Bone homeostasis is maintained by the coupled actions of hematopoietic bone-resorbing osteoclasts (OCs) and mesenchymal bone-forming osteoblasts (OBs). Here we identify early B cell factor 1 (Ebf1) and the transcriptional coregulator Zfp521 as components of the machinery that regulates bone homeostasis through coordinated effects in both lineages. Deletion of Zfp521 in OBs led to impaired bone formation and increased OB-dependent osteoclastogenesis (OC-genesis), and deletion in hematopoietic cells revealed a strong cell-autonomous role for Zfp521 in OC progenitors. In adult mice, the effects of Zfp521 were largely caused by repression of Ebf1, and the bone phenotype of Zfp521+/− mice was rescued in Zfp521+/−:Ebf1+/− mice. Zfp521 interacted with Ebf1 and repressed its transcriptional activity. Accordingly, deletion of Zfp521 led to increased Ebf1 activity in OBs and OCs. In vivo, Ebf1 overexpression in OBs resulted in suppressed bone formation, similar to the phenotype seen after OB-targeted deletion of Zfp521. Conversely, Ebf1 deletion led to cell-autonomous defects in both OB-dependent and cell-intrinsic OC-genesis, a phenotype opposite to that of the Zfp521 knockout. Thus, we have identified the interplay between Zfp521 and Ebf1 as a novel rheostat for bone homeostasis. PMID:23569325

Expansion of Endothelial Progenitor Cells in High Density Dot Culture of Rat Bone Marrow Cells

PubMed Central

Wang, Ling; Kretlow, James D.; Zhou, Guangdong; Cao, Yilin; Liu, Wei; Zhang, Wen Jie

2014-01-01

In vitro expansion of endothelial progenitor cells (EPCs) remains a challenge in stem cell research and its application. We hypothesize that high density culture is able to expand EPCs from bone marrow by mimicking cell-cell interactions of the bone marrow niche. To test the hypothesis, rat bone marrow cells were either cultured in high density (2×105 cells/cm2) by seeding total 9×105 cells into six high density dots or cultured in regular density (1.6×104 cells/cm2) with the same total number of cells. Flow cytometric analyses of the cells cultured for 15 days showed that high density cells exhibited smaller cell size and higher levels of marker expression related to EPCs when compared to regular density cultured cells. Functionally, these cells exhibited strong angiogenic potentials with better tubal formation in vitro and potent rescue of mouse ischemic limbs in vivo with their integration into neo-capillary structure. Global gene chip and ELISA analyses revealed up-regulated gene expression of adhesion molecules and enhanced protein release of pro-angiogenic growth factors in high density cultured cells. In summary, high density cell culture promotes expansion of bone marrow contained EPCs that are able to enhance tissue angiogenesis via paracrine growth factors and direct differentiation into endothelial cells. PMID:25254487

Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge.

PubMed

Yang, Wencheng; Dong, Youhai; Hong, Yang; Guang, Qian; Chen, Xujun

2016-05-01

The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge. We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge. Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion. Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery. New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups II and IV. These findings suggest that mesenchymal stem cells that have been cultured with osteogenic differentiation medium and loaded with collagen sponge could induce bone formation and anterior vertebral interbody fusion. And the rabbit model we developed will be useful in evaluating the effects of graft materials for anterior vertebral interbody fusion. Further study is needed to determine the most appropriate carrier for OMSCs and the feasibility in the clinical setting.

Fabrication and Characterization of Carbon Fiber-Reinforced Nano-Hydroxyapatite/Polyamide46 Biocomposite for Bone Substitute.

PubMed

Deng, Zhennan; Han, Hongjuan; Yang, Jingyuan; Li, Yuanyuan; Du, Shengnan; Ma, Jianfeng

2017-05-24

BACKGROUND Ideal bone repair material should be of good biocompatibility and high bioactivity. Besides, their mechanical properties should be equivalent to those of natural bone. The objective of this study was to fabricate a novel biocomposite suitable for load-bearing bone defect repair. MATERIAL AND METHODS A novel biocomposite composed of carbon fiber, hydroxyapatite and polyamide46 (CF/HA/PA46) was fabricated, and its mechanical performances and preliminary cell responses were evaluated to explore its feasibility for load-bearing bone defect repair. RESULTS The resultant CF/HA/PA46 biocomposite showed a bending strength of 159-223 MPa, a tensile strength of 127-199 MPa and a tensile modulus of 7.7-10.8 GPa, when the CF content was 5-20% (mass fraction) in biocomposite. The MG63 cells, showing an osteogenic phenotype, were well adhered and spread on the surface of the CF/HA/PA46 biocomposite. Moreover, the cells vitality and differentiation on the CF/HA/PA46 biocomposite surface were obviously increased during the culture time and there was no significant difference between the CF/HA/PA46 biocomposite and HA/PA (as control) at all the experimental time (P>0.05). CONCLUSIONS The addition of CF into HA/PA46 composite manifest improved the mechanical performances and showed favorable effects on biocompatibility of MG63 cells. The obtained biocomposite has high potential for bone repair in load-bearing sites.

Fabrication and Characterization of Carbon Fiber-Reinforced Nano-Hydroxyapatite/Polyamide46 Biocomposite for Bone Substitute

PubMed Central

Deng, Zhennan; Han, Hongjuan; Yang, Jingyuan; Li, Yuanyuan; Du, Shengnan; Ma, Jianfeng

2017-01-01

Background Ideal bone repair material should be of good biocompatibility and high bioactivity. Besides, their mechanical properties should be equivalent to those of natural bone. The objective of this study was to fabricate a novel biocomposite suitable for load-bearing bone defect repair. Material/Methods A novel biocomposite composed of carbon fiber, hydroxyapatite and polyamide46 (CF/HA/PA46) was fabricated, and its mechanical performances and preliminary cell responses were evaluated to explore its feasibility for load-bearing bone defect repair. Results The resultant CF/HA/PA46 biocomposite showed a bending strength of 159–223 MPa, a tensile strength of 127–199 MPa and a tensile modulus of 7.7–10.8 GPa, when the CF content was 5–20% (mass fraction) in biocomposite. The MG63 cells, showing an osteogenic phenotype, were well adhered and spread on the surface of the CF/HA/PA46 biocomposite. Moreover, the cells vitality and differentiation on the CF/HA/PA46 biocomposite surface were obviously increased during the culture time and there was no significant difference between the CF/HA/PA46 biocomposite and HA/PA (as control) at all the experimental time (P>0.05). Conclusions The addition of CF into HA/PA46 composite manifest improved the mechanical performances and showed favorable effects on biocompatibility of MG63 cells. The obtained biocomposite has high potential for bone repair in load-bearing sites. PMID:28536416

Hydrostatic pressure in combination with topographical cues affects the fate of bone marrow-derived human mesenchymal stem cells for bone tissue regeneration.

PubMed

Reinwald, Yvonne; El Haj, Alicia J

2018-03-01

Topographical and mechanical cues are vital for cell fate, tissue development in vivo, and to mimic the native cell growth environment in vitro. To date, the combinatory effect of mechanical and topographical cues as not been thoroughly investigated. This study investigates the effect of PCL nanofiber alignment and hydrostatic pressure on stem cell differentiation for bone tissue regeneration. Bone marrow-derived human mesenchymal stem cells were seeded onto standard tissue culture plastic and electrospun random and aligned nanofibers. These substrates were either cultured statically or subjected to intermittent hydrostatic pressure at 270 kPa, 1 Hz for 60 min daily over 21 days in osteogenic medium. Data revealed higher cell metabolic activities for all mechanically stimulated cell culture formats compared with non-stimulated controls; and random fibers compared with aligned fibers. Fiber orientation influenced cell morphology and patterns of calcium deposition. Significant up-regulation of Collagen-I, ALP, and Runx-2 were observed for random and aligned fibers following mechanical stimulation; highest levels of osteogenic markers were expressed when hydrostatic pressure was applied to random fibers. These results indicate that fiber alignment and hydrostatic pressure direct stem cell fate and are important stimulus for tissue regeneration. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: A: 629-640, 2018. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

PI3K inhibitor GDC-0941 enhances apoptotic effects of BH-3 mimetic ABT-737 in AML cells in the hypoxic bone marrow microenvironment

PubMed Central

Kojima, Kensuke; Shikami, Masato; Benito, Julina; Ruvolo, Vivian; Wang, Rui-Yu; McQueen, Teresa; Ciurea, Stefan O.; Miida, Takashi; Andreeff, Michael; Konopleva, Marina

2013-01-01

Both phosphatidylinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling and antiapoptotic Bcl-2 family members are critical for survival of acute myeloid leukemia (AML) cells. Here we demonstrate the antileukemic effects of simultaneous inhibition of PI3K by the selective class I PI3K inhibitor GDC-0941 and of Bcl-2 family members by the BH3 mimetic ABT-737 in the context of the bone marrow microenvironment, where hypoxia and interactions with bone marrow stromal cells promote AML cell survival and chemoresistance. The combination of GDC-0941 and ABT-737 profoundly downregulated antiapoptotic Mcl-1 expression levels, activated BAX, and induced mitochondrial apoptosis in AML cells co-cultured with bone marrow stromal cells under hypoxic conditions. Hypoxia caused degradation of Mcl-1 and rendered Mcl-1-overexpressing OCI-AML3 cells sensitive to ABT-737. Our findings suggest that pharmacologic PI3K inhibition by GDC-0941 enhances ABT-737–induced leukemia cell death even under the protective conditions afforded by the bone marrow microenvironment. PMID:23955073

Fabrication of Metallic Biomedical Scaffolds with the Space Holder Method: A Review

PubMed Central

Arifvianto, Budi; Zhou, Jie

2014-01-01

Bone tissue engineering has been increasingly studied as an alternative approach to bone defect reconstruction. In this approach, new bone cells are stimulated to grow and heal the defect with the aid of a scaffold that serves as a medium for bone cell formation and growth. Scaffolds made of metallic materials have preferably been chosen for bone tissue engineering applications where load-bearing capacities are required, considering the superior mechanical properties possessed by this type of materials to those of polymeric and ceramic materials. The space holder method has been recognized as one of the viable methods for the fabrication of metallic biomedical scaffolds. In this method, temporary powder particles, namely space holder, are devised as a pore former for scaffolds. In general, the whole scaffold fabrication process with the space holder method can be divided into four main steps: (i) mixing of metal matrix powder and space-holding particles; (ii) compaction of granular materials; (iii) removal of space-holding particles; (iv) sintering of porous scaffold preform. In this review, detailed procedures in each of these steps are presented. Technical challenges encountered during scaffold fabrication with this specific method are addressed. In conclusion, strategies are yet to be developed to address problematic issues raised, such as powder segregation, pore inhomogeneity, distortion of pore sizes and shape, uncontrolled shrinkage and contamination. PMID:28788638

Local Controlled Release of Polyphenol Conjugated with Gelatin Facilitates Bone Formation

PubMed Central

Honda, Yoshitomo; Tanaka, Tomonari; Tokuda, Tomoko; Kashiwagi, Takahiro; Kaida, Koji; Hieda, Ayato; Umezaki, Yasuyuki; Hashimoto, Yoshiya; Imai, Koichi; Matsumoto, Naoyuki; Baba, Shunsuke; Shimizutani, Kimishige

2015-01-01

Catechins are extensively used in health care treatments. Nevertheless, there is scarce information about the feasibility of local administration with polyphenols for bone regeneration therapy, possibly due to lack of effective delivery systems. Here we demonstrated that the epigallocatechin-3-gallate-conjugated gelatin (EGCG/Gel) prepared by an aqueous chemical synthesis using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-morpholinium chloride (DMT-MM) gradually disintegrated with time and facilitated bone formation in a critical size defect of a mouse calvaria. Conjugation of EGCG with the Gel generated cross-linking between the two molecules, thereby leading to a retardation of the degradation of the EGCG/Gel and to a delayed release of EGCG. The prepared EGCG/Gels represented significant osteogenic capability compared with that of the uncross-linked Gel and the cross-linked Gel with uncombined-EGCG. In vitro experiments disclosed that the EGCG/Gel induced osteoblastogenesis of a mouse mesenchymal stem cell line (D1 cells) within 14 days. Using fluorescently-labeled EGCG/Gel, we found that the fraction of EGCG/Gel adsorbed onto the cell membrane of the D1 cells possibly via a Gel-cell interaction. The interaction might confer the long-term effects of EGCG on the cells, resulting in a potent osteogenic capability of the EGCG/Gel in vivo. These results should provide insight into local controlled release of polyphenols for bone therapy. PMID:26110386

An improved interfacial bonding model for material interface modeling

PubMed Central

Lin, Liqiang; Wang, Xiaodu; Zeng, Xiaowei

2016-01-01

An improved interfacial bonding model was proposed from potential function point of view to investigate interfacial interactions in polycrystalline materials. It characterizes both attractive and repulsive interfacial interactions and can be applied to model different material interfaces. The path dependence of work-of-separation study indicates that the transformation of separation work is smooth in normal and tangential direction and the proposed model guarantees the consistency of the cohesive constitutive model. The improved interfacial bonding model was verified through a simple compression test in a standard hexagonal structure. The error between analytical solutions and numerical results from the proposed model is reasonable in linear elastic region. Ultimately, we investigated the mechanical behavior of extrafibrillar matrix in bone and the simulation results agreed well with experimental observations of bone fracture. PMID:28584343

Simulation of bone resorption-repair coupling in vitro.

PubMed

Jones, S J; Gray, C; Boyde, A

1994-10-01

In the normal adult human skeleton, new bone formation by osteoblasts restores the contours of bone surfaces following osteoclastic bone resorption, but the evidence for resorption-repair coupling remains circumstantial. To investigate whether sites of prior resorption, more than the surrounding unresorbed surface, attract osteoblasts or stimulate them to proliferate or make new matrix, we developed a simple in vitro system in which resorption-repair coupling occurs. Resorption pits were produced in mammalian dentine or bone slabs by culturing chick bone-derived cells on them for 2-3 days. The chick cells were swept off and the substrata reseeded with rat calvarial osteoblastic cells, which make bone nodules in vitro, for periods of up to 8 weeks. Cell positions and new bone formation were investigated by ordinary light microscopy, fluorescence and reflection confocal laser microscopy, and SEM, in stained and unstained samples. There was no evidence that the osteoblasts were especially attracted to, or influenced by, the sites of resorption in dentine or bone before cell confluence was reached. Bone formation was identified by light microscopy by the accumulation of matrix, staining with alizarin and calcein and by von Kossa's method, and confirmed by scanning electron microscopy (SEM) by using backscattered electron (BSE) and transmitted electron imaging of unembedded samples and BSE imaging of micro-milled embedded material. These new bone patches were located initially in the resorption pits. The model in vitro system may throw new light on the factors that control resorption-repair coupling in the mineralised tissues in vivo.

A feasibility study for in vitro evaluation of fixation between prosthesis and bone with bone marrow-derived mesenchymal stem cells.

PubMed

Morita, Yusuke; Yamasaki, Kenichi; Hattori, Koji

2010-10-01

It is difficult to quantitatively evaluate adhesive strength between an implant and the neighboring bone using animal experiments, because the degree of fixation of an implant depends on differences between individuals and the clearance between the material and the bone resulting from surgical technique. A system was designed in which rat bone marrow cells were used to quantitatively evaluate the adhesion between titanium alloy plates and bone plates in vitro. Three kinds of surface treatment were used: a sand-blasted surface, a titanium-sprayed surface and a titanium-sprayed surface coated with hydroxyapatite. Bone marrow cells obtained from rat femora were seeded on the titanium alloy plates, and the cells were cultured between the titanium alloy plates and the bone plates sliced from porcine ilium for 2 weeks. After cultivation, adhesive strength was measured using a tensile test, after which DNA amount and Alkaline phosphatase activity were measured. The seeded cells accelerated adhesion of the titanium alloy plate to the bone plate. Adhesive strength of the titanium-sprayed surface was lower than that of the sand-blasted surface because of lower initial contact area, although there was no difference in Alkaline phosphatase activity between two surface treatments. A hydroxyapatite coating enhanced adhesive strength between the titanium alloy palate and the bone plate, as well as enhancing osteogenic differentiation of bone marrow cells. It is believed that this novel experimental method can be used to simultaneously evaluate the osteogenic differentiation and the adhesive strength of an implant during in vitro cultivation. 2010 Elsevier Ltd. All rights reserved.

The Influence of Peptide Modifications of Bioactive Glass on Human Mesenchymal Stem Cell Growth and Function

NASA Astrophysics Data System (ADS)

Ammar, Mohamed

2011-12-01

Bioactive glass is known for its potential as a bone scaffold due to its ability to stimulate osteogenesis and induce bone formation. Broadening this potential to include the differentiation of human mesenchymal stem cells (hMSCs) to bone cells will enhance the healing process in bone defects. The surface of bioactive glass made by the sol-gel technique with the composition of 70% SiO2-30% CaO (mol %) was grafted with 3 peptides sequences in different combinations from proteins (fibronectin BMP-2 and BMP-9) that are known to promote the adhesion, differentiation and osteogenesis process. The experiment was done in two forms, a 2D non-porous thin film and a 3D nano-macroporous structure. hMSCs were grown on the materials for a total of five weeks. The 2D materials were tested for the expression of 3 osteogenic markers (osteopontin, osteocalcin and osteonectin) through immunocytochemistry. The 3D forms were monitored for cell's adhesion, morphology, spreading and proliferation by scanning electron microscopy, in addition to proliferation assay and alkaline phosphatase activity measurement. Results showed that hMSCs poorly adhered to the 2D thin films, but the few cells survived showed enhanced expression of the osteogenic markers. On the 3D form, cells showed enhanced proliferation at week one and more survival of the cells on the materials grafted with the adhesion peptide for the successive weeks in comparison to the positive control samples. Enhanced alkaline phosphatase activity was also detected compared to the negative control samples but were still below the positive control samples. In conclusion, the peptide grafting could increase the effect of bioactive glass but more peptide combinations should be examined to improve the effects on the differentiation and osteogenic activity of the hMSCs.

Biocompatibility evaluation of HDPE-UHMWPE reinforced β-TCP nanocomposites using highly purified human osteoblast cells.

PubMed

Shokrgozar, M A; Farokhi, M; Rajaei, F; Bagheri, M H A; Azari, Sh; Ghasemi, I; Mottaghitalab, F; Azadmanesh, K; Radfar, J

2010-12-15

Biocompatibility of β-TCP/HDPE-UHMWPE nanocomposite as a new bone substitute material was evaluated by using highly purified human osteoblast cells. Human osteoblast cells were isolated from bone tissue and characterized by immunofluorescence Staining before and after purification using magnetic bead system. Moreover, proliferation, alkaline phosphatase production, cell attachment, calcium deposition, gene expression, and morphology of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposites were evaluated. The results have shown that the human osteoblast cells were successfully purified and were suitable for subsequent cell culturing process. The high proliferation rate of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposite confirmed the great biocompatibility of the scaffold. Expression of bone-specific genes was taken place after the cells were incubated in composite extract solutions. Furthermore, osteoblast cells were able to mineralize the matrix next to composite samples. Scanning electron microscopy demonstrated that cells had normal morphology on the scaffold. Thus, these results indicated that the nanosized β-TCP/HDPE-UHMWPE blend composites could be potential scaffold, which is used in bone tissue engineering. Copyright © 2010 Wiley Periodicals, Inc.

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

PubMed Central

Adam, Martin; Ganz, Cornelia; Xu, Weiguo; Sarajian, Hamid-Reza; Götz, Werner; Gerber, Thomas

2014-01-01

Immediate loading of dental implants is only possible if a firm bone-implant anchorage at early stages is developed. This implies early and high bone apposition onto the implant surface. A nanostructured coating material based on an osseoinductive bone grafting is investigated in relation to the osseointegration at early stages. The goal is to transmit the structure (silica matrix with embedded hydroxyapatite) and the properties of the bone grafting into a coating material. The bone grafting substitute offers an osseoinductive potential caused by an exchange of the silica matrix in vivo accompanied by vascularization. X-ray diffraction and transmission electron microscopy analysis show that the coating material consists of a high porous silica matrix with embedded nanocrystalline hydroxyapatite with the same morphology as human hydroxyapatite. An in vitro investigation shows the early interaction between coating and human blood. Energy-dispersive X-ray analysis showed that the silica matrix was replaced by an organic matrix within a few minutes. Uncoated and coated titanium implants were inserted into the femora of New Zealand White rabbits. The bone-to-implant contact (BIC) was measured after 2, 4, and 6 weeks. The BIC of the coated implants was increased significantly at 2 and 4 weeks. After 6 weeks, the BIC was decreased to the level of the control group. A histological analysis revealed high bone apposition on the coated implant surface after 2 and 4 weeks. Osteoblastic and osteoclastic activities on the coating material indicated that the coating participates in the bone-remodeling process. The nanostructure of the coating material led to an exchange of the silica matrix by an autologous, organic matrix without delamination of the coating. This is the key issue in understanding initial bone formation on a coated surface. PMID:24627631

Bone sialoprotein does not interact with pro-gelatinase A (MMP-2) or mediate MMP-2 activation.

PubMed

Hwang, Queena; Cheifetz, Sela; Overall, Christopher M; McCulloch, Christopher A; Sodek, Jaro

2009-04-22

A recent model for activation of the zymogen form of matrix metalloproteinase 2 (MMP-2, also known as gelatinase A) has suggested that interactions between the SIBLING protein bone sialoprotein (BSP) and MMP-2 leads to conformational change in MMP-2 that initiates the conversion of the pro-enzyme into a catalytically active form. This model is particularly relevant to cancer cell metastasis to bone since BSP, bound to the alphavbeta3 integrin through its arginine-glycine-aspartic acid motif, could recruit MMP-2 to the cell surface. We critically assessed the relationship between BSP and proMMP-2 and its activation using various forms of recombinant and purified BSP and MMP-2. Gelatinase and collagenase assays, fluorescence binding assays, real-time PCR, cell culture and pull-down assays were employed to test the model. Studies with a fluorogenic substrate for MMP-2 showed no activation of proMMP-2 by BSP. Binding and pull-down assays demonstrated no interaction between MMP-2 and BSP. While BSP-mediated invasiveness has been shown to depend on its integrin-binding RGD sequence, analysis of proMMP-2 activation and the level of membrane type 1 (MT1)-MMP in cells grown on a BSP substratum showed that the BSP-alphavbeta3 integrin interaction does not induce the expression of MT1-MMP. These studies do not support a role for BSP in promoting metastasis through interactions with pro-MMP-2.

Bioglass incorporation improves mechanical properties and enhances cell-mediated mineralization on electrochemically aligned collagen threads.

PubMed

Nijsure, Madhura P; Pastakia, Meet; Spano, Joseph; Fenn, Michael B; Kishore, Vipuil

2017-09-01

Bone tissue engineering mandates the development of a functional scaffold that mimics the physicochemical properties of native bone. Bioglass 45S5 (BG) is a highly bioactive material known to augment bone formation and restoration. Hybrid scaffolds fabricated using collagen type I and BG resemble the organic and inorganic composition of the bone extracellular matrix and hence have been extensively investigated for bone tissue engineering applications. However, collagen-BG scaffolds developed thus far do not recapitulate the aligned structure of collagen found in native bone. In this study, an electrochemical fabrication method was employed to synthesize BG-incorporated electrochemically aligned collagen (BG-ELAC) threads that are compositionally similar to native bone. Further, aligned collagen fibrils within BG-ELAC threads mimic the anisotropic arrangement of collagen fibrils in native bone. The effect of BG incorporation on the mechanical properties and cell-mediated mineralization on ELAC threads was investigated. The results indicated that BG can be successfully incorporated within ELAC threads, without disturbing collagen fibril alignment. Further, BG incorporation significantly increased the ultimate tensile stress (UTS) and modulus of ELAC threads (p < 0.05). SBF conditioning showed extensive mineralization on BG-ELAC threads that increased over time demonstrating the bone bioactivity of BG-ELAC threads. Additionally, BG incorporation into ELAC threads resulted in increased cell proliferation (p < 0.05) and deposition of a highly dense and continuous mineralized matrix. In conclusion, incorporation of BG into ELAC threads is a viable strategy for the development of an osteoconductive material for bone tissue engineering applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2429-2440, 2017. © 2017 Wiley Periodicals, Inc.

Long-term culture and differentiation of porcine red bone marrow hematopoietic cells co-cultured with immortalized mesenchymal cells.

PubMed

Garba, Abubakar; Acar, Delphine D; Roukaerts, Inge D M; Desmarets, Lowiese M B; Devriendt, Bert; Nauwynck, Hans J

2017-09-01

Mesenchymal cells are multipotent stromal cells with self-renewal, differentiation and immunomodulatory capabilities. We aimed to develop a co-culture model for differentiating hematopoietic cells on top of immortalized mesenchymal cells for studying interactions between hematopoietic and mesenchymal cells, useful for adequately exploring the therapeutic potential of mesenchymal cells. In this study, we investigated the survival, proliferation and differentiation of porcine red bone marrow hematopoietic cells co-cultured with immortalized porcine bone marrow mesenchymal cells for a period of five weeks. Directly after collection, primary porcine bone marrow mesenchymal cells adhered firmly to the bottom of the culture plates and showed a fibroblast-like appearance, one week after isolation. Upon immortalization, porcine bone marrow mesenchymal cells were continuously proliferating. They were positive for simian virus 40 (SV40) large T antigen and the mesenchymal cell markers CD44 and CD55. Isolated red bone marrow cells were added to these immortalized mesenchymal cells. Five weeks post-seeding, 92±6% of the red bone marrow hematopoietic cells were still alive and their number increased 3-fold during five weekly subpassages on top of the immortalized mesenchymal cells. The red bone marrow hematopoietic cells were originally small and round; later, the cells increased in size. Some of them became elongated, while others remained round. Tiny dendrites appeared attaching hematopoietic cells to the underlying immortalized mesenchymal cells. Furthermore, weekly differential-quick staining of the cells indicated the presence of monoblasts, monocytes, macrophages and lymphocytes in the co-cultures. At three weeks of co-culture, flow cytometry analysis showed an increased surface expression of CD172a, CD14, CD163, CD169, CD4 and CD8 up to 37±0.8%, 40±8%, 41±4%, 23±3% and 19±5% of the hematopoietic cells, respectively. In conclusion, continuous mesenchymal cell cultures were successfully established and characterized and they supported the proliferation of red bone marrow hematopoietic cells, which finally differentiated into monocytic cells and CD4 + and CD8 + cells. Copyright © 2017. Published by Elsevier B.V.

Automated Quantification of Hematopoietic Cell – Stromal Cell Interactions in Histological Images of Undecalcified Bone

PubMed Central

Zehentmeier, Sandra; Cseresnyes, Zoltan; Escribano Navarro, Juan; Niesner, Raluca A.; Hauser, Anja E.

2015-01-01

Confocal microscopy is the method of choice for the analysis of localization of multiple cell types within complex tissues such as the bone marrow. However, the analysis and quantification of cellular localization is difficult, as in many cases it relies on manual counting, thus bearing the risk of introducing a rater-dependent bias and reducing interrater reliability. Moreover, it is often difficult to judge whether the co-localization between two cells results from random positioning, especially when cell types differ strongly in the frequency of their occurrence. Here, a method for unbiased quantification of cellular co-localization in the bone marrow is introduced. The protocol describes the sample preparation used to obtain histological sections of whole murine long bones including the bone marrow, as well as the staining protocol and the acquisition of high-resolution images. An analysis workflow spanning from the recognition of hematopoietic and non-hematopoietic cell types in 2-dimensional (2D) bone marrow images to the quantification of the direct contacts between those cells is presented. This also includes a neighborhood analysis, to obtain information about the cellular microenvironment surrounding a certain cell type. In order to evaluate whether co-localization of two cell types is the mere result of random cell positioning or reflects preferential associations between the cells, a simulation tool which is suitable for testing this hypothesis in the case of hematopoietic as well as stromal cells, is used. This approach is not limited to the bone marrow, and can be extended to other tissues to permit reproducible, quantitative analysis of histological data. PMID:25938636

Three-dimensional plotted alginate fibers embedded with diclofenac and bone cells coated with chitosan for bone regeneration during inflammation.

PubMed

Lin, Hsin-Yi; Chang, Tsang-Wen; Peng, Tie-Kun

2018-06-01

Alginate hydrogel fibers embedded with bone cells and diclofenac were coated with a layer of chitosan hydrogel and made into a porous scaffold by three-dimensional (3D) printing for drug release and bone regeneration. It was hypothesized that the chitosan coating could improve the scaffold's drug retention and release properties and biocompatibility. Macrophage cells were stimulated and cocultured with the scaffold. Tests were conducted to show how the chitosan coating affected the scaffold's drug release efficacy and how the release efficacy affected the cellular activities of stimulated macrophages and bone cells. The bone cells encapsulated in the coated scaffold demonstrated good viability after the acidic/basic coating process. The coating improved the retention and release efficacy of diclofenac and hence significantly inhibited interleukin-6 and tumor necrosis factor-α secretion from macrophages (p < 0.05). The bone cells in the coated sample mineralized more extensively than the control (p < 0.01). They also more actively expressed genes that produce proteins for extracellular matrix remodeling, MMP13, and interacting with the mineral matrix, OPN (both p < 0.01). It is believed that on days 7 and 10, when diclofenac was depleted and the concentrations of inflammatory compounds surged, the coating effectively blocked the harmful compounds and protected the bone cells within the fibers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1511-1521, 2018. © 2018 Wiley Periodicals, Inc.

Study of a novel three-dimensional scaffold to repair bone defect in rabbit.

PubMed

Chen, Yushu; Bai, Bo; Zhang, Shujiang; Ye, Jing; Zhai, Haohan; Chen, Yi; Zhang, Linlin; Zeng, Yanjun

2014-05-01

Both decalcified bone matrix (DBM) and fibrin gel possess good biocompatibility, so they are used as scaffolds to culture bone marrow mesenchymal stem cells (BMSCs). The feasibility and efficacy of using compound material being made of decalcified bone matrix and fibrin gel as a three-dimensional scaffold for bone growth were investigated. BMSCs were isolated from the femur of rabbit, then seeded in prepared scaffolds after incubation for 28 days in vitro. In vivo: 30 New Zealand White Rabbits received bone defect in left radius and divided three treatment groups randomly: (1) BMSCs/decalcified bone matrix/fibrin glue as experimental group; (2) decalcified bone matrix/fibrin glue without cells as control group; (3) nothing was implanted into the bone defects as blank group. The observation period of specimens was 12 weeks, and were analyzed bone formation in terms of serum proteomics (2D-PAGE and MALDI-TOF-TOF-MS), hematoxylin-eosin (HE) staining, ALP staining, and Osteopontin immunofluorescence detection. The experimental group present in three peculiar kinds of proteins, whose Geninfo identifier (GI) number were 136466, 126722803, and 126723746, respectively, correspond to TTR protein, ALB protein, RBP4 protein, and the histological inspections were superior to the other group. The content of osteopontin in experimental group was significantly higher than control group (p <  0.05). The overall results indicated that a combined material being made of BMSCs/decalcified bone matrix/fibrin glue can result in successful bone formation and decalcified bone matrix/fibrin glue admixtures can be used as a scaffold for bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

Regulation of Extracellular Matrix Remodeling Proteins by Osteoblasts in Titanium Nanoparticle-Induced Aseptic Loosening Model.

PubMed

Xie, Jing; Hou, Yanhua; Fu, Na; Cai, Xiaoxiao; Li, Guo; Peng, Qiang; Lin, Yunfeng

2015-10-01

Titanium (Ti)-wear particles, formed at the bone-implant interface, are responsible for aseptic loosening, which is a main cause of total joint replacement failure. There have been many studies on Ti particle-induced function changes in mono-cultured osteoblasts and synovial cells. However, little is known on extracellular matrix remodeling displayed by osteoblasts when in coexistence with Synovial cells. To further mimic the bone-implant interface environment, we firstly established a nanoscaled-Ti particle-induced aseptic loosening system by co-culturing osteoblasts and Synovial cells. We then explored the impact of the Synovial cells on Ti particle-engulfed osteoblasts in the mimicked flamed niche. The matrix metalloproteinases and lysyl oxidases expression levels, two protein families which are critical in osseointegration, were examined under induction by tumor necrosis factor-alpha. It was found that the co-culture between the osteoblasts and Synovial cells markedly increased the migration and proliferation of the osteoblasts, even in the Ti-particle engulfed osteoblasts. Importantly, the Ti-particle engulfed osteoblasts, induced by TNF-alpha after the co-culture, enhanced the release of the matrix metalloproteinases and reduced the expressions of lysyl oxidases. The regulation of extracellular matrix remodeling at the protein level was further assessed by investigations on gene expression of the matrix metalloproteinases and lysyl oxidases, which also suggested that the regulation started at the genetic level. Our research work has therefore revealed the critical role of multi cell-type interactions in the extracellular matrix remodeling within the peri-prosthetic tissues, which provides new insights on aseptic loosening and brings new clues about incomplete osseointegration between the implantation materials and their surrounding bones.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair.

PubMed

Tandon, Biranche; Blaker, Jonny J; Cartmell, Sarah H

2018-04-16

The process of bone repair and regeneration requires multiple physiological cues including biochemical, electrical and mechanical - that act together to ensure functional recovery. Myriad materials have been explored as bioactive scaffolds to deliver these cues locally to the damage site, amongst these piezoelectric materials have demonstrated significant potential for tissue engineering and regeneration, especially for bone repair. Piezoelectric materials have been widely explored for power generation and harvesting, structural health monitoring, and use in biomedical devices. They have the ability to deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need of an external power source. Bone itself is piezoelectric and the charges/potentials it generates in response to mechanical activity are capable of enhancing bone growth. Piezoelectric materials are capable of stimulating the physiological electrical microenvironment, and can play a vital role to stimulate regeneration and repair. This review gives an overview of the association of piezoelectric effect with bone repair, and focuses on state-of-the-art piezoelectric materials (polymers, ceramics and their composites), the fabrication routes to produce piezoelectric scaffolds, and their application in bone repair. Important characteristics of these materials from the perspective of bone tissue engineering are highlighted. Promising upcoming strategies and new piezoelectric materials for this application are presented. Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing interest of the scientific community and compelling results of the published research articles has been the motivation of this review article. This article summarizes the significant progress in the field with a focus on the fabrication aspects of piezoelectric materials. The review of both material and cellular aspects on this topic ensures that this paper appeals to both material scientists and tissue engineers. Copyright © 2018. Published by Elsevier Ltd.

Bone tissue engineering with a collagen–hydroxyapatite scaffold and culture expanded bone marrow stromal cells

PubMed Central

Villa, Max M.; Wang, Liping; Huang, Jianping; Rowe, David W.; Wei, Mei

2015-01-01

Osteoprogenitor cells combined with supportive biomaterials represent a promising approach to advance the standard of care for bone grafting procedures. However, this approach faces challenges, including inconsistent bone formation, cell survival in the implant, and appropriate biomaterial degradation. We have developed a collagen–hydroxyapatite (HA) scaffold that supports consistent osteogenesis by donor derived osteoprogenitors, and is more easily degraded than a pure ceramic scaffold. Herein, the material properties are characterized as well as cell attachment, viability, and progenitor distribution in vitro. Furthermore, we examined the biological performance in vivo in a critical-size mouse calvarial defect. To aid in the evaluation of the in-house collagen–HA scaffold, the in vivo performance was compared with a commercial collagen–HA scaffold (Healos®, Depuy). The in-house collagen–HA scaffold supported consistent bone formation by predominantly donor-derived osteoblasts, nearly completely filling a 3.5 mm calvarial defect with bone in all samples (n=5) after 3 weeks of implantation. In terms of bone formation and donor cell retention at 3 weeks postimplantation, no statistical difference was found between the in-house and commercial scaffold following quantitative histomorphometry. The collagen–HA scaffold presented here is an open and well-defined platform that supports robust bone formation and should facilitate the further development of collagen–hydroxyapatite biomaterials for bone tissue engineering. PMID:24909953

Image-based RNA interference screening reveals an individual dependence of acute lymphoblastic leukemia on stromal cysteine support

PubMed Central

Marovca, Blerim; Vonderheit, Andreas; Grotzer, Michael A.; Eckert, Cornelia; Cario, Gunnar; Wollscheid, Bernd; Horvath, Peter

2014-01-01

Interactions with the bone marrow microenvironment are essential for leukemia survival and disease progression. We developed an imaging-based RNAi platform to identify protective cues from bone marrow derived mesenchymal stromal cells (MSC) that promote survival of primary acute lymphoblastic leukemia (ALL) cells. Using a candidate gene approach, we detected distinct responses of individual ALL cases to RNA interference with stromal targets. The strongest effects were observed when interfering with solute carrier family 3 member 2 (SLC3A2) expression, which forms the cystine transporter xc− when associated with SLC7A11. Import of cystine and metabolism to cysteine by stromal cells provides the limiting substrate to generate and maintain glutathione in ALL. This metabolic interaction reduces oxidative stress in ALL cells that depend on stromal xc−. Indeed, cysteine depletion using cysteine dioxygenase resulted in leukemia cell death. Thus, functional evaluation of intercellular interactions between leukemia cells and their microenvironment identifies a selective dependency of ALL cells on stromal metabolism for a relevant subgroup of cases, providing new opportunities to develop more personalized approaches to leukemia treatment. PMID:25415224

Ceramic and non-ceramic hydroxyapatite as a bone graft material: a brief review.

PubMed

Dutta, S R; Passi, D; Singh, P; Bhuibhar, A

2015-03-01

Treatment of dental, craniofacial and orthopedic defects with bone graft substitutes has shown promising result achieving almost complete bone regeneration depending on product resorption similar to human bone's physicochemical and crystallographic characteristics. Among these, non-ceramic and ceramic hydroxyapatite being the main inorganic salt of bone is the most studied calcium phosphate material in clinical practices ever since 1970s and non-ceramic since 1985. Its "chemical similarity" with the mineralized phase of biologic bone makes it unique. Hydroxyapatite as an excellent carrier of osteoinductive growth factors and osteogenic cell populations is also useful as drug delivery vehicle regardless of its density. Porous ceramic and non-ceramic hydroxyapatite is osteoconductive, biocompatible and very inert. The need for bone graft material keeps on increasing with increased age of the population and the increased conditions of trauma. Recent advances in genetic engineering and doping techniques have made it possible to use non-ceramic hydroxyapatite in larger non-ceramic crystals and cluster forms as a successful bone graft substitute to treat various types of bone defects. In this paper we have mentioned some recently studied properties of hydroxyapatite and its various uses through a brief review of the literatures available to date.

Enhanced cell adhesion on bioinert ceramics mediated by the osteogenic cell membrane enzyme alkaline phosphatase.

PubMed

Aminian, Alieh; Shirzadi, Bahareh; Azizi, Zahra; Maedler, Kathrin; Volkmann, Eike; Hildebrand, Nils; Maas, Michael; Treccani, Laura; Rezwan, Kurosch

2016-12-01

Functional bone and dental implant materials are required to guide cell response, offering cues that provide specific instructions to cells at the implant/tissue interface while maintaining full biocompatibility as well as the desired structural requirements and functions. In this work we investigate the influence of covalently immobilized alkaline phosphatase (ALP), an enzyme involved in bone mineralization, on the first contact and initial cell adhesion. To this end, ALP is covalently immobilized by carbodiimide-mediated chemoligation on two highly bioinert ceramics, alpha-alumina (Al2O3) and yttria-stabilized zirconia (Y-TZP) that are well-established for load-bearing applications. The physicochemical surface properties are evaluated by profilometry, zeta potential and water contact angle measurements. The initial cell adhesion of human osteoblasts (HOBs), human osteoblast-like cells (MG-63) and mesenchymal stromal cells (hMSCs) was investigated. Cell adhesion was assessed at serum free condition via quantification of percentage of adherent cells, adhesion area and staining of the focal adhesion protein vinculin. Our findings show that after ALP immobilization, the Al2O3 and Y-TZP surfaces gained a negative charge and their hydrophilicity was increased. In the presence of surface-immobilized ALP, a higher cell adhesion, more pronounced cell spreading and a higher number of focal contact points were found. Thereby, this work gives evidence that surface functionalization with ALP can be utilized to modify inert materials for biological conversion and faster bone regeneration on inert and potentially load-bearing implant materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Tetraspanin CD9 participates in dysmegakaryopoiesis and stromal interactions in primary myelofibrosis.

PubMed

Desterke, Christophe; Martinaud, Christophe; Guerton, Bernadette; Pieri, Lisa; Bogani, Costanza; Clay, Denis; Torossian, Frederic; Lataillade, Jean-Jacques; Hasselbach, Hans C; Gisslinger, Heinz; Demory, Jean-Loup; Dupriez, Brigitte; Boucheix, Claude; Rubinstein, Eric; Amsellem, Sophie; Vannucchi, Alessandro M; Le Bousse-Kerdilès, Marie-Caroline

2015-06-01

Primary myelofibrosis is characterized by clonal myeloproliferation, dysmegakaryopoiesis, extramedullary hematopoiesis associated with myelofibrosis and altered stroma in the bone marrow and spleen. The expression of CD9, a tetraspanin known to participate in megakaryopoiesis, platelet formation, cell migration and interaction with stroma, is deregulated in patients with primary myelofibrosis and is correlated with stage of myelofibrosis. We investigated whether CD9 participates in the dysmegakaryopoiesis observed in patients and whether it is involved in the altered interplay between megakaryocytes and stromal cells. We found that CD9 expression was modulated during megakaryocyte differentiation in primary myelofibrosis and that cell surface CD9 engagement by antibody ligation improved the dysmegakaryopoiesis by restoring the balance of MAPK and PI3K signaling. When co-cultured on bone marrow mesenchymal stromal cells from patients, megakaryocytes from patients with primary myelofibrosis displayed modified behaviors in terms of adhesion, cell survival and proliferation as compared to megakaryocytes from healthy donors. These modifications were reversed after antibody ligation of cell surface CD9, suggesting the participation of CD9 in the abnormal interplay between primary myelofibrosis megakaryocytes and stroma. Furthermore, silencing of CD9 reduced CXCL12 and CXCR4 expression in primary myelofibrosis megakaryocytes as well as their CXCL12-dependent migration. Collectively, our results indicate that CD9 plays a role in the dysmegakaryopoiesis that occurs in primary myelofibrosis and affects interactions between megakaryocytes and bone marrow stromal cells. These results strengthen the "bad seed in bad soil" hypothesis that we have previously proposed, in which alterations of reciprocal interactions between hematopoietic and stromal cells participate in the pathogenesis of primary myelofibrosis. Copyright© Ferrata Storti Foundation.

The Osteogenic Niche Promotes Early-Stage Bone Colonization of Disseminated Breast Cancer Cells

PubMed Central

Wang, Hai; Yu, Cuijuan; Gao, Xia; Welte, Thomas; Muscarella, Aaron M.; Tian, Lin; Zhao, Hong; Zhao, Zhen; Du, Shiyu; Tao, Jianning; Lee, Brendan; Westbrook, Thomas F.; Wong, Stephen T. C.; Jin, Xin; Rosen, Jeffrey M.; Osborne, C. Kent; Zhang, Xiang H.-F.

2014-01-01

Summary Breast cancer bone micrometastases can remain asymptomatic for years before progressing into overt lesions. The biology of this process, including the microenvironment niche and supporting pathways, is unclear. We find that bone micrometastases predominantly reside in a niche that exhibits features of osteogenesis. Niche interactions are mediated by heterotypic adherens junctions (hAJs) involving cancer-derived E-cadherin and osteogenic N-cadherin, the disruption of which abolishes niche-conferred advantages. We further elucidate that hAJ activates the mTOR pathway in cancer cells, which drives the progression from single cells to micrometastases. Human datasets analyses support the roles of AJ and the mTOR pathway in bone colonization. Our study illuminates the initiation of bone colonization, and provides potential therapeutic targets to block progression toward osteolytic metastases. Significance In advanced stages, breast cancer bone metastases are driven by paracrine crosstalk among cancer cells, osteoblasts, and osteoclasts, which constitute a vicious osteolytic cycle. Current therapies targeting this process limit tumor progression, but do not improve patient survival. On the other hand, bone micrometastases may remain indolent for years before activating the vicious cycle, providing a therapeutic opportunity to prevent macrometastases. Here, we show that bone colonization is initiated in a microenvironment niche exhibiting active osteogenesis. Cancer and osteogenic cells form heterotypic adherens junctions, which enhance mTOR activity and drive early-stage bone colonization prior to osteolysis. These results reveal a strong connection between osteogenesis and micrometastasis and suggest potential therapeutic targets to prevent bone macrometastases. PMID:25600338

Mesenchymal stem cells inhibit RANK-RANKL interactions between osteoclasts and Th17 cells via osteoprotegerin activity

PubMed Central

Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee; Ryu, Kyung-Ha; Woo, So-Youn

2017-01-01

Th17 cells play a critical role in several autoimmune diseases, including psoriasis and psoriatic arthritis (PsA). Psoriasis is a chronic inflammatory skin disease associated with systemic inflammation and comorbidities, such as PsA. PsA develops in nearly 70% of patients with psoriasis, and osteoclasts associated bone erosion is a hallmark of the disease. Thus far, the effect of Th17 cells on osteoclastogenesis via direct cell-to-cell interactions is less understood. In this study, we observed that Th17 cells directly promote osteoclast differentiation and maturation via expression of receptor activator of nuclear factor-κ β ligand (RANKL) in vitro. We investigated the impact of conditioned medium obtained from human palatine tonsil-derived mesenchymal stem cells (T-CM) on the interactions between osteoclasts and Th17 cells. T-CM effectively blunted the RANK-RANKL interaction between the osteoclast precursor cell line RAW 264.7 and Th17 cells via osteoprotegerin (OPG) activity. The frequency of tartrate-resistant acid phosphatase (TRAP)-positive cells in the bone marrow of an imiquimod (IMQ)-induced psoriasis mouse model was decreased following T-CM injection. Therefore, our data provide novel insight into the therapeutic potential of tonsil-derived mesenchymal stem cell-mediated therapy (via OPG production) for the treatment of pathophysiologic processes induced by osteoclasts under chronic inflammatory conditions such as psoriasis. PMID:29137353

Microfluidic co-culture platform for investigating osteocyte-osteoclast signalling during fluid shear stress mechanostimulation.

PubMed

Middleton, K; Al-Dujaili, S; Mei, X; Günther, A; You, L

2017-07-05

Bone cells exist in a complex environment where they are constantly exposed to numerous dynamic biochemical and mechanical stimuli. These stimuli regulate bone cells that are involved in various bone disorders, such as osteoporosis. Knowledge of how these stimuli affect bone cells have been utilised to develop various treatments, such as pharmaceuticals, hormone therapy, and exercise. To investigate the role that bone loading has on these disorders in vitro, bone cell mechanotransduction studies are typically performed using parallel plate flow chambers (PPFC). However, these chambers do not allow for dynamic cellular interactions among different cell populations to be investigated. We present a microfluidic approach that exposes different cell populations, which are located at physiologically relevant distances within adjacent channels, to different levels of fluid shear stress, and promotes cell-cell communication between the different channels. We employed this microfluidic system to assess mechanically regulated osteocyte-osteoclast communication. Osteoclast precursors (RAW264.7 cells) responded to cytokine gradients (e.g., RANKL, OPG, PGE-2) developed by both mechanically stimulated (fOCY) and unstimulated (nOCY) osteocyte-like MLO-Y4 cells simultaneously. Specifically, we observed increased osteoclast precursor cell densities and osteoclast differentiation towards nOCY. We also used this system to show an increased mechanoresponse of osteocytes when in co-culture with osteoclasts. We envision broad applicability of the presented approach for microfluidic perfusion co-culture of multiple cell types in the presence of fluid flow stimulation, and as a tool to investigate osteocyte mechanotransduction, as well as bone metastasis extravasation. This system could also be applied to any multi-cell population cross-talk studies that are typically performed using PPFCs (e.g. endothelial cells, smooth muscle cells, and fibroblasts). Copyright © 2017 Elsevier Ltd. All rights reserved.

The bone marrow niche, stem cells, and leukemia: impact of drugs, chemicals, and the environment.

PubMed

Snyder, Robert

2014-03-01

Detection, treatment, and prevention of bone marrow diseases have long been the aims of experimental and clinical hematologists and mechanistically oriented toxicologists. Among these diseases is aplastic anemia, which manifests as the cessation of normal blood cell production; the leukemias, in contrast, feature the production of excessive hematologic cancer cells. Both diseases are associated with exposure to either industrial chemicals or cancer chemotherapeutic agents. Studies of hematopoietic bone marrow cells in culture have shown that the generation of circulating blood cells requires the interaction of hematopoietic stem cells (HSCs) with supporting marrow stromal cells; yet, isolation of HSCs from bone destroys the unique morphology of the marrow stroma in which the HSCs reside. Imaging techniques and related studies have made it possible to examine specific niches where HSCs may either initiate differentiation toward mature blood cells or reside in a dormant state awaiting a signal to begin differentiation. HSCs and related cells may be highly vulnerable to the mutagenic or toxic effects of drugs or other chemicals early in these processes. Additional studies are required to determine the mechanisms by which drug or chemical exposure may affect these cells and lead to either depression of bone marrow function or to leukemia. © 2014 New York Academy of Sciences.

Mapping the physical network of cellular interactions.

PubMed

Boisset, Jean-Charles; Vivié, Judith; Grün, Dominic; Muraro, Mauro J; Lyubimova, Anna; van Oudenaarden, Alexander

2018-05-21

A cell's function is influenced by the environment, or niche, in which it resides. Studies of niches usually require assumptions about the cell types present, which impedes the discovery of new cell types or interactions. Here we describe ProximID, an approach for building a cellular network based on physical cell interaction and single-cell mRNA sequencing, and show that it can be used to discover new preferential cellular interactions without prior knowledge of component cell types. ProximID found specific interactions between megakaryocytes and mature neutrophils and between plasma cells and myeloblasts and/or promyelocytes (precursors of neutrophils) in mouse bone marrow, and it identified a Tac1 + enteroendocrine cell-Lgr5 + stem cell interaction in small intestine crypts. This strategy can be used to discover new niches or preferential interactions in a variety of organs.

Evaluation of nanoparticles of hydroxyapatite and MWCNT’s in scaffolds of poly lactic acid

NASA Astrophysics Data System (ADS)

Román-Doval, R.; Morales-Corona, J.; Olayo, R.; Escamilla-Rivera, V.; Uribe-Ramírez, M.; Ortega-López, M.

2016-12-01

In the tissue engineering, the cytotoxicity test is an important part of the biomaterials performance. This research reports the production and characterization of polylactic acid (PLA)-supported hydroxyapatite (HA) and multiwalled carbon nanotubes (MWCNT) scaffolds as a bone graft material. Samples containing different HA/MWCNT wt% ratios were prepared by electrospinning. The obtained samples displayed valuable characteristics for the cell adhesion because of their porous-spongy bone-like morphology. The Fourier transforms infrared and Raman analyses indicated no chemical interaction of HA and MWCNT with PLA molecules, but they appear to be only embedded into the PLA fibers. As indicated by x-ray diffraction, crystalline HA and MWCNT’s are supported in the amorphous PLA fibers. Under tensile stress, scaffolds display a Young’s Modulus about 86 MPa, whilst the scaffolds resistance increases with the HA-MWCNT’s ratio. However, the MTS in-vitro assays using the hFOB 1.19 (ATCC CRL-11372) cells, for cell exposure time of 24 and 48 h, revealed that viability reduces for HA-MWCNT’s ratio values over 25 wt%. Our results suggest that a maximum HA/MWCNT’s ratio of 19:1 could be acceptable for cell proliferation while maintaining HA at 200 mg.

Changes in physicochemical and biological properties of porcine bone derived hydroxyapatite induced by the incorporation of fluoride

NASA Astrophysics Data System (ADS)

Qiao, Wei; Liu, Quan; Li, Zhipeng; Zhang, Hanqing; Chen, Zhuofan

2017-12-01

As the main inorganic component of xenogenic bone graft material, bone-derived biological apatite (BAp) has been widely used in implant dentistry, oral and maxillofacial surgery and orthopedics. However, BAp produced via calcination of animal bones still suffers from some drawbacks, such as insufficient mechanical strength and inadequate degradation rate, which impede its application. Fluoride is known to play important roles in both physiological and pathological processes of human hard tissues for its double effects on bones and teeth. In order to understand the effects of fluoride on the properties of BAp, as well as the mechanism behind them, porcine bone derived hydroxyapatite (PHAp) was prepared via thermal treatment, which was then fluoride incorporated at a series concentrations of sodium fluoride, and noted as 0.25-FPHAp, 0.50-FPHAp, and 0.75-FPHAp respectively. The physicochemical characteristics of the materials, including crystal morphology, crystallinity, functional groups, elemental composition, compressive strength, porosity and solubility, were then determined. The biological properties, such as protein adsorption and cell attachment, were also evaluated. It was found that the spheroid-like crystals of PHAp were changed into rod-like after fluoride substitution, resulting in a fluoride concentration-dependent increase in compressive strength, as well as a decreased porosity and solubility of the apatite. However, even though the addition of fluoride was demonstrated to enhance protein adsorption and cell attachment of the materials, the most favorable results were intriguingly achieved in FPHAp with the least fluoride content. Collectively, low level of fluoride incorporation is proposed promising for the modification of clinically used BAp based bone substitute materials, because of its being able to maintain a good balance between physicochemical and biological properties of the apatite.

Osteoconductive carriers for integrated bone repair

PubMed Central

Ganey, Timothy; Hutton, William; Meisel, Hans Jörg

2009-01-01

Successful bone repair is judged in achieving restitution of space and mechanical integrity, and in regaining function. When the biology or anatomy are insufficient to attain a full repair, therapeutic use of graft material has been used to omit compliance features such as strain tolerance, reduced stiffness, and attenuated strength, and instead promote primary or membranous-type bone formation within the physical approximation of a graft material. The challenge of most conductive materials is that they emerge from a static platform and in placement force the living system to adapt to placement, dimension, different properties, and eventually are only successful in degradation and replacement, or in integration. The synergy and interdependency between adhesion, ECM, and proteolysis are important concepts that must be understood to engineer scaffolds capable of holding up to standards which are more than cell decoration. Moreover, the reactive specificity to loading, degradation, therapeutic delivery during absorption remains a key aim of both academic and industrial designs. Achieving conductivity comes with challenges of best fit integration, delivery, and in integrated modeling. The more liquid is the delivery, the more modular the components, and adaptive the matrix to meeting the intended application, the more likely that the conductivity will not be excluded by the morphology of the injury site. Considerations for osteoconductive materials for bone repair and replacement have developed conceptually and advanced parallel with a better understanding of not only bone biology but of materials science. First models of material replacements utilized a reductionist-constructionist logic; define the constituents of the material in terms of its morphology and chemical composition, and then engineer material with similar content and properties as a means of accommodating a replacement. Unfortunately for biologic systems, empiric formulation is insufficient to promote adequate integration in a timely fashion. Future matrices will need to translate their biological surfaces as more than a scaffold to be decorated with cells. Conductivity will be improved by formulations that enhance function, further extended from understanding what composition best suits cell attachment, and be adopted by conveniences of delivery that meet those criteria. PMID:25802634

Osteoconductive carriers for integrated bone repair.

PubMed

Ganey, Timothy; Hutton, William; Meisel, Hans Jörg

2009-01-01

Successful bone repair is judged in achieving restitution of space and mechanical integrity, and in regaining function. When the biology or anatomy are insufficient to attain a full repair, therapeutic use of graft material has been used to omit compliance features such as strain tolerance, reduced stiffness, and attenuated strength, and instead promote primary or membranous-type bone formation within the physical approximation of a graft material. The challenge of most conductive materials is that they emerge from a static platform and in placement force the living system to adapt to placement, dimension, different properties, and eventually are only successful in degradation and replacement, or in integration. The synergy and interdependency between adhesion, ECM, and proteolysis are important concepts that must be understood to engineer scaffolds capable of holding up to standards which are more than cell decoration. Moreover, the reactive specificity to loading, degradation, therapeutic delivery during absorption remains a key aim of both academic and industrial designs. Achieving conductivity comes with challenges of best fit integration, delivery, and in integrated modeling. The more liquid is the delivery, the more modular the components, and adaptive the matrix to meeting the intended application, the more likely that the conductivity will not be excluded by the morphology of the injury site. Considerations for osteoconductive materials for bone repair and replacement have developed conceptually and advanced parallel with a better understanding of not only bone biology but of materials science. First models of material replacements utilized a reductionist-constructionist logic; define the constituents of the material in terms of its morphology and chemical composition, and then engineer material with similar content and properties as a means of accommodating a replacement. Unfortunately for biologic systems, empiric formulation is insufficient to promote adequate integration in a timely fashion. Future matrices will need to translate their biological surfaces as more than a scaffold to be decorated with cells. Conductivity will be improved by formulations that enhance function, further extended from understanding what composition best suits cell attachment, and be adopted by conveniences of delivery that meet those criteria.

Behavior of bone cells in contact with magnesium implant material.

PubMed

Burmester, Anna; Willumeit-Römer, Regine; Feyerabend, Frank

2017-01-01

Magnesium-based implants exhibit several advantages, such as biodegradability and possible osteoinductive properties. Whether the degradation may induce cell type-specific changes in metabolism still remains unclear. To examine the osteoinductivity mechanisms, the reaction of bone-derived cells (MG63, U2OS, SaoS2, and primary human osteoblasts (OB)) to magnesium (Mg) was determined. Mg-based extracts were used to mimic more realistic Mg degradation conditions. Moreover, the influence of cells having direct contact with the degrading Mg metal was investigated. In exposure to extracts and in direct contact, the cells decreased pH and osmolality due to metabolic activity. Proliferating cells showed no significant reaction to extracts, whereas differentiating cells were negatively influenced. In contrast to extract exposure, where cell size increased, in direct contact to magnesium, cell size was stable or even decreased. The amount of focal adhesions decreased over time on all materials. Genes involved in bone formation were significantly upregulated, especially for primary human osteoblasts. Some osteoinductive indicators were observed for OB: (i) an increased cell count after extract addition indicated a higher proliferation potential; (ii) increased cell sizes after extract supplementation in combination with augmented adhesion behavior of these cells suggest an early switch to differentiation; and (iii) bone-inducing gene expression patterns were determined for all analyzed conditions. The results from the cell lines were inhomogeneous and showed no specific stimulus of Mg. The comparison of the different cell types showed that primary cells of the investigated tissue should be used as an in vitro model if Mg is analyzed. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 165-179, 2017. © 2015 Wiley Periodicals, Inc.

Three-Dimensional Mechanical Loading Modulates the Osteogenic Response of Mesenchymal Stem Cells to Tumor-Derived Soluble Signals.

PubMed

Lynch, Maureen E; Chiou, Aaron E; Lee, Min Joon; Marcott, Stephen C; Polamraju, Praveen V; Lee, Yeonkyung; Fischbach, Claudia

2016-08-01

Dynamic mechanical loading is a strong anabolic signal in the skeleton, increasing osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) and increasing the bone-forming activity of osteoblasts, but its role in bone metastatic cancer is relatively unknown. In this study, we integrated a hydroxyapatite-containing three-dimensional (3D) scaffold platform with controlled mechanical stimulation to investigate the effects of cyclic compression on the interplay between breast cancer cells and BM-MSCs as it pertains to bone metastasis. BM-MSCs cultured within mineral-containing 3D poly(lactide-co-glycolide) (PLG) scaffolds differentiated into mature osteoblasts, and exposure to tumor-derived soluble factors promoted this process. When BM-MSCs undergoing osteogenic differentiation were exposed to conditioned media collected from mechanically loaded breast cancer cells, their gene expression of osteopontin was increased. This was further enhanced when mechanical compression was simultaneously applied to BM-MSCs, leading to more uniformly deposited osteopontin within scaffold pores. These results suggest that mechanical loading of 3D scaffold-based culture models may be utilized to evaluate the role of physiologically relevant physical cues on bone metastatic breast cancer. Furthermore, our data imply that cyclic mechanical stimuli within the bone microenvironment modulate interactions between tumor cells and BM-MSCs that are relevant to bone metastasis.

The influence of environmental factors on bone tissue engineering.

PubMed

Szpalski, Caroline; Sagebin, Fabio; Barbaro, Marissa; Warren, Stephen M

2013-05-01

Bone repair and regeneration are dynamic processes that involve a complex interplay between the substrate, local and systemic cells, and the milieu. Although each constituent plays an integral role in faithfully recreating the skeleton, investigators have long focused their efforts on scaffold materials and design, cytokine and hormone administration, and cell-based therapies. Only recently have the intangible aspects of the milieu received their due attention. In this review, we highlight the important influence of environmental factors on bone tissue engineering. Copyright © 2012 Wiley Periodicals, Inc.

Fabrication and characterization of a novel carbon fiber-reinforced calcium phosphate silicate bone cement with potential osteo-inductivity.

PubMed

Zheng, Jiangjiang; Xiao, Yu; Gong, Tianxing; Zhou, Shuxin; Troczynski, Tom; Yang, Quanzu; Bao, Chongyun; Xu, Xiaoming

2015-12-23

The repair of bone defects is still a pressing challenge in clinics. Injectable bone cement is regarded as a promising material to solve this problem because of its special self-setting property. Unfortunately, its poor mechanical conformability, unfavorable osteo-genesis ability and insufficient osteo-inductivity seriously limit its clinical application. In this study, novel experimental calcium phosphate silicate bone cement reinforced by carbon fibers (CCPSC) was fabricated and characterized. First, a compressive strength test and cell culture study were carried out. Then, the material was implanted into the femoral epiphysis of beagle dogs to further assess its osteo-conductivity using a micro-computed tomography scan and histological analysis. In addition, we implanted CCPSC into the beagles' intramuscular pouches to perform an elementary investigation of its osteo-inductivity. The results showed that incorporation of carbon fibers significantly improved its mechanical properties. Meanwhile, CCPSC had better biocompatibility to activate cell adhesion as well as proliferation than poly-methyl methacrylate bone cement based on the cell culture study. Moreover, pronounced biodegradability and improved osteo-conductivity of CCPSC could be observed through the in vivo animal study. Finally, a small amount of osteoid was found at the heterotopic site one month after implantation which indicated potential osteo-inductivity of CCPSC. In conclusion, the novel CCPSC shows promise as a bioactive bone substitute in certain load-bearing circumstances.

Reticulated vitreous carbon: a useful material for cell adhesion and tissue invasion.

PubMed

Pec, M K; Reyes, R; Sánchez, E; Carballar, D; Delgado, A; Santamaría, J; Arruebo, M; Evora, C

2010-10-06

Diverse carbon materials have been used for tissue engineering and clinical implant applications with varying success. In this study, commercially available reticulated vitreous carbon (RVC) foams were tested in vitro and in vivo for compatibility with primary cell adhesion and tissue repair. Pores sizes were determined as 279 ± 98 μm. No hydroxyapatite deposition was detected after immersion of the foams in simulated body fluid. Nonetheless, RVC provided an excellent support for adhesion of mesenchymal stem cells (MSCs) as well as primary chondrocytes without any surface pre-treatment. Live cell quantification revealed neutral behaviour of the material with plastic adhered chondrocytes but moderate cytotoxicity with MSCs. Yet, rabbit implanted foams exhibited good integration in subcutaneous pockets and most importantly, total defect repair in bone. Probably due to the stiffness of the material, incompatibility with cartilage regeneration was found. Interestingly and in contrast to several other carbon materials, we observed a total lack of foreign body reactions. Our results and its outstanding porous interconnectivity and availability within a wide range of pore sizes convert RVC into an attractive candidate for tissue engineering applications in a variety of bone models and for ex vivo cell expansion for regenerative medical applications.

Bare Bones of Bioactive Glass

NASA Technical Reports Server (NTRS)

2000-01-01

Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Even in normal gravity, bioactive glass particles enhance bone growth in laboratory tests with flat tissue cultures. Ducheyne and his team believe that using the bioactive microcarriers in a rotating bioreactor in microgravity will produce improved, three-dimensional tissue cultures. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and University of Pennsylvania Center for Bioactive Materials and Tissue Engineering.

Perfusion electrodeposition of calcium phosphate on additive manufactured titanium scaffolds for bone engineering.

PubMed

Chai, Yoke Chin; Truscello, Silvia; Bael, Simon Van; Luyten, Frank P; Vleugels, Jozef; Schrooten, Jan

2011-05-01

A perfusion electrodeposition (P-ELD) system was reported to functionalize additive manufactured Ti6Al4V scaffolds with a calcium phosphate (CaP) coating in a controlled and reproducible manner. The effects and interactions of four main process parameters - current density (I), deposition time (t), flow rate (f) and process temperature (T) - on the properties of the CaP coating were investigated. The results showed a direct relation between the parameters and the deposited CaP mass, with a significant effect for t (P=0.001) and t-f interaction (P=0.019). Computational fluid dynamic analysis showed a relatively low electrolyte velocity within the struts and a high velocity in the open areas within the P-ELD chamber, which were not influenced by a change in f. This is beneficial for promoting a controlled CaP deposition and hydrogen gas removal. Optimization studies showed that a minimum t of 6 h was needed to obtain complete coating of the scaffold regardless of I, and the thickness was increased by increasing I and t. Energy-dispersive X-ray and X-ray diffraction analysis confirmed the deposition of highly crystalline synthetic carbonated hydroxyapatite under all conditions (Ca/P ratio=1.41). High cell viability and cell-material interactions were demonstrated by in vitro culture of human periosteum derived cells on coated scaffolds. This study showed that P-ELD provides a technological tool to functionalize complex scaffold structures with a biocompatible CaP layer that has controlled and reproducible physicochemical properties suitable for bone engineering. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Sphingosine 1-Phosphate (S1P) Receptors 1 and 2 Coordinately Induce Mesenchymal Cell Migration through S1P Activation of Complementary Kinase Pathways*

PubMed Central

Quint, Patrick; Ruan, Ming; Pederson, Larry; Kassem, Moustapha; Westendorf, Jennifer J.; Khosla, Sundeep; Oursler, Merry Jo

2013-01-01

Normal bone turnover requires tight coupling of bone resorption and bone formation to preserve bone quantity and structure. With aging and during several pathological conditions, this coupling breaks down, leading to either net bone loss or excess bone formation. To preserve or restore normal bone metabolism, it is crucial to determine the mechanisms by which osteoclasts and osteoblast precursors interact and contribute to coupling. We showed that osteoclasts produce the chemokine sphingosine 1-phosphate (S1P), which stimulates osteoblast migration. Thus, osteoclast-derived S1P may recruit osteoblasts to sites of bone resorption as an initial step in replacing lost bone. In this study we investigated the mechanisms by which S1P stimulates mesenchymal (skeletal) cell chemotaxis. S1P treatment of mesenchymal (skeletal) cells activated RhoA GTPase, but this small G protein did not contribute to migration. Rather, two S1P receptors, S1PR1 and S1PR2, coordinately promoted migration through activation of the JAK/STAT3 and FAK/PI3K/AKT signaling pathways, respectively. These data demonstrate that the chemokine S1P couples bone formation to bone resorption through activation of kinase signaling pathways. PMID:23300082

Biomaterials for Bone Regenerative Engineering.

PubMed

Yu, Xiaohua; Tang, Xiaoyan; Gohil, Shalini V; Laurencin, Cato T

2015-06-24

Strategies for bone tissue regeneration have been continuously evolving for the last 25 years since the introduction of the "tissue engineering" concept. The convergence of the life, physical, and engineering sciences has brought in several advanced technologies available to tissue engineers and scientists. This resulted in the creation of a new multidisciplinary field termed as "regenerative engineering". In this article, the role of biomaterials in bone regenerative engineering is systematically reviewed to elucidate the new design criteria for the next generation of biomaterials for bone regenerative engineering. The exemplary design of biomaterials harnessing various materials characteristics towards successful bone defect repair and regeneration is highlighted. Particular attention is given to the attempts of incorporating advanced materials science, stem cell technologies, and developmental biology into biomaterials design to engineer and develop the next generation bone grafts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Imaging stem cell distribution, growth, migration, and differentiation in 3-D scaffolds for bone tissue engineering using mesoscopic fluorescence tomography.

PubMed

Tang, Qinggong; Piard, Charlotte; Lin, Jonathan; Nan, Kai; Guo, Ting; Caccamese, John; Fisher, John; Chen, Yu

2018-01-01

Regenerative medicine has emerged as an important discipline that aims to repair injury or replace damaged tissues or organs by introducing living cells or functioning tissues. Successful regenerative medicine strategies will likely depend upon a simultaneous optimization strategy for the design of biomaterials, cell-seeding methods, cell-biomaterial interactions, and molecular signaling within the engineered tissues. It remains a challenge to image three-dimensional (3-D) structures and functions of the cell-seeded scaffold in mesoscopic scale (>2 ∼ 3 mm). In this study, we utilized angled fluorescence laminar optical tomography (aFLOT), which allows depth-resolved molecular characterization of engineered tissues in 3-D to investigate cell viability, migration, and bone mineralization within bone tissue engineering scaffolds in situ. © 2017 Wiley Periodicals, Inc.

Hydrogels with tunable stress relaxation regulate stem cell fate and activity

PubMed Central

Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

2015-01-01

Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel’s initial elastic modulus, cell-adhesion-ligand density and degradation. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture. PMID:26618884

Calcium supplementation decreases BCP-induced inflammatory processes in blood cells through the NLRP3 inflammasome down-regulation.

PubMed

Lagadec, Patricia; Balaguer, Thierry; Boukhechba, Florian; Michel, Grégory; Bouvet-Gerbettaz, Sébastien; Bouler, Jean-Michel; Scimeca, Jean-Claude; Rochet, Nathalie

2017-07-15

Interaction of host blood with biomaterials is the first event occurring after implantation in a bone defect. This study aimed at investigating the cellular and molecular consequences arising at the interface between whole blood and biphasic calcium phosphate (BCP) particles. We observed that, due to calcium capture, BCP inhibited blood coagulation, and that this inhibition was reversed by calcium supplementation. Therefore, we studied the impact of calcium supplementation on BCP effects on blood cells. Comparative analysis of BCP and calcium supplemented-BCP (BCP/Ca) effects on blood cells showed that BCP as well as BCP/Ca induced monocyte proliferation, as well as a weak but significant hemolysis. Our data showed for the first time that calcium supplementation of BCP microparticles had anti-inflammatory properties compared to BCP alone that induced an inflammatory response in blood cells. Our results strongly suggest that the anti-inflammatory property of calcium supplemented-BCP results from its down-modulating effect on P2X7R gene expression and its capacity to inhibit ATP/P2X7R interactions, decreasing the NLRP3 inflammasome activation. Considering that monocytes have a vast regenerative potential, and since the excessive inflammation often observed after bone substitutes implantation limits their performance, our results might have great implications in terms of understanding the mechanisms leading to an efficient bone reconstruction. Although scaffolds and biomaterials unavoidably come into direct contact with blood during bone defect filling, whole blood-biomaterials interactions have been poorly explored. By studying in 3D the interactions between biphasic calcium phosphate (BCP) in microparticulate form and blood, we showed for the first time that calcium supplementation of BCP microparticles (BCP/Ca) has anti-inflammatory properties compared to BCP-induced inflammation in whole blood cells and provided information related to the molecular mechanisms involved. The present study also showed that BCP, as well as BCP/Ca particles stimulate monocyte proliferation. As monocytes represent a powerful target for regenerative therapies and as an excessive inflammation limits the performance of biomaterials in bone tissue engineering, our results might have great implications to improve bone reconstruction. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Emerging Perspectives in Scaffold for Tissue Engineering in Oral Surgery.

PubMed

Ceccarelli, Gabriele; Presta, Rossella; Benedetti, Laura; Cusella De Angelis, Maria Gabriella; Lupi, Saturnino Marco; Rodriguez Y Baena, Ruggero

2017-01-01

Bone regeneration is currently one of the most important and challenging tissue engineering approaches in regenerative medicine. Bone regeneration is a promising approach in dentistry and is considered an ideal clinical strategy in treating diseases, injuries, and defects of the maxillofacial region. Advances in tissue engineering have resulted in the development of innovative scaffold designs, complemented by the progress made in cell-based therapies. In vitro bone regeneration can be achieved by the combination of stem cells, scaffolds, and bioactive factors. The biomimetic approach to create an ideal bone substitute provides strategies for developing combined scaffolds composed of adult stem cells with mesenchymal phenotype and different organic biomaterials (such as collagen and hyaluronic acid derivatives) or inorganic biomaterials such as manufactured polymers (polyglycolic acid (PGA), polylactic acid (PLA), and polycaprolactone). This review focuses on different biomaterials currently used in dentistry as scaffolds for bone regeneration in treating bone defects or in surgical techniques, such as sinus lift, horizontal and vertical bone grafts, or socket preservation. Our review would be of particular interest to medical and surgical researchers at the interface of cell biology, materials science, and tissue engineering, as well as industry-related manufacturers and researchers in healthcare, prosthetics, and 3D printing, too.

Origins of endothelial and osteogenic cells in the subcutaneous collagen gel implant.

PubMed

Bilic-Curcic, I; Kalajzic, Z; Wang, L; Rowe, D W

2005-11-01

The interdependent relationship between vascular endothelial cells and osteoblasts during bone formation and fracture healing has been long appreciated. This paper reports a heterotopic implant model using FGF-2-expanded bone marrow stromal cells (BMSC) derived from Tie2eGFP (endothelial marker) and pOBCol3.6GFPcyan or topaz (early osteoblast marker) transgenic mice to appreciate the host/donor relationships of cells participating in the process of heterotopic bone formation. The study included various combinations of Tie2eGFP and pOBCol3.6GFPcyan and topaz transgenics as BMSC or whole bone marrow (WBM) donors and also as recipients. Rat tail collagen was used as a carrier of donor cells and implantation was done in lethally irradiated mice rescued with WBM injection. Development of ossicles in the implants was followed weekly during the 4- to 5-week long post-implantation period. By 4-5 weeks after total body irradiation (TBI) and implantation, a well-formed bone spicule had developed that was invested with bone marrow. Experiments showed absolute dominance of donor-derived cells in the formation of endothelial-lined vessels inside the implants as well as the marrow stromal-derived osteogenic cells. Host-derived fibroblasts and osteogenic cells were confined to the fibrous capsule surrounding the implant. In addition, cells lining the endosteal surface of newly formed marrow space carrying a pOBCol3.6GFP marker were observed that were contributed by WBM donor cells and the host. Thus, FGF-2-expanded BMSC appear to be a source of endothelial and osteogenic progenitor cells capable of eliciting heterotopic bone formation independent of cells from the host. This model should be useful for understanding the interactions between these two cell types that control osteogenic differentiation in vivo.

Lithotripter shock wave interaction with a bubble near various biomaterials.

PubMed

Ohl, S W; Klaseboer, E; Szeri, A J; Khoo, B C

2016-10-07

Following previous work on the dynamics of an oscillating bubble near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a bubble with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas bubble with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The bubble is situated in water (to represent a water-like biofluid). The bubble collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation bubbles (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave bubble biomaterial interactions. If a subsequent rarefaction wave hits the collapsed bubble, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone-water interface can affect the bubble dynamics. Also the initial size of the bubble has a significant effect. Large bubbles (∼1 mm) will split into smaller bubbles, while small bubbles collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a bubble, a shock wave, and a nearby bio-material.

Cabozantinib Affects Osteosarcoma Growth Through A Direct Effect On Tumor Cells and Modifications In Bone Microenvironment.

PubMed

Fioramonti, M; Fausti, V; Pantano, F; Iuliani, M; Ribelli, G; Lotti, F; Pignochino, Y; Grignani, G; Santini, D; Tonini, G; Vincenzi, B

2018-03-08

Osteosarcoma (OS) is the most common primary malignant tumor of the bone. Due to its high heterogeneity and to survival signals from bone microenvironment, OS can resist to standard treatments, therefore novel therapies are needed. c-MET oncogene, a tyrosine-kinase receptor, plays a crucial role in OS initiation and progression. The present study aimed to evaluate the effect of c-MET inhibitor cabozantinib (CBZ) on OS both directly and through its action on bone microenvironment. We tested different doses of CBZ in in vitro models of OS alone or in co-culture with bone cells in order to reproduce OS-tumor microenvironment interactions. CBZ is able to decrease proliferation and migration of OS cells, inhibiting ERK and AKT signaling pathways. Furthermore, CBZ leads to the inhibition of the proliferation of OS cells expressing receptor activator of nuclear factor κB (RANK), due to its effect on bone microenvironment, where it causes an overproduction of osteoprotegerin and a decrease of production of RANK ligand by osteoblasts. Overall, our data demonstrate that CBZ might represent a new potential treatment against OS, affecting both OS cells and their microenvironment. In this scenario, RANK expression in OS cells could represent a predictive factor of better response to CBZ treatment.

Silk fibroin/chitosan thin film promotes osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells.

PubMed

Li, Da-Wei; He, Jin; He, Feng-Li; Liu, Ya-Li; Liu, Yang-Yang; Ye, Ya-Jing; Deng, Xudong; Yin, Da-Chuan

2018-04-01

As a biodegradable polymer thin film, silk fibroin/chitosan composite film overcomes the defects of pure silk fibroin and chitosan films, respectively, and shows remarkable biocompatibility, appropriate hydrophilicity and mechanical properties. Silk fibroin/chitosan thin film can be used not only as metal implant coating for bone injury repair, but also as tissue engineering scaffold for skin, cornea, adipose, and other soft tissue injury repair. However, the biocompatibility of silk fibroin/chitosan thin film for mesenchymal stem cells, a kind of important seed cell of tissue engineering and regenerative medicine, is rarely reported. In this study, silk fibroin/chitosan film was prepared by solvent casting method, and the rat bone marrow-derived mesenchymal stem cells were cultured on the silk fibroin/chitosan thin film. Osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells were induced, respectively. The proliferation ability, osteogenic and adipogenic differentiation abilities of rat bone marrow-derived mesenchymal stem cells were systematically compared between silk fibroin/chitosan thin film and polystyrene tissue culture plates. The results showed that silk fibroin/chitosan thin film not only provided a comparable environment for the growth and proliferation of rat bone marrow-derived mesenchymal stem cells but also promoted their osteogenic and adipogenic differentiation. This work provided information of rat bone marrow-derived mesenchymal stem cells behavior on silk fibroin/chitosan thin film and extended the application of silk fibroin/chitosan thin film. Based on the results, we suggested that the silk fibroin/chitosan thin film could be a promising material for tissue engineering of bone, cartilage, adipose, and skin.

Characterization of bone tissue using microstrip antennas.

PubMed

Barros, Jannayna D; de Oliveira, Jose Josemar; da Silva, Sandro G

2010-01-01

The use of electromagnetic waves in the characterization of biological tissues has been conducted since the nineteenth century after the confirmation that electric and magnetic fields can interact with biological materials. In this paper, electromagnetic waves are used to characterize tissues with different levels of bone mass. In this way, one antenna array on microstrip lines was used. It can be seen that bones with different mass has different behavior in microwave frequencies.

Neutral buoyancy and sleep-deprived serum factors alter expression of cytokines regulating osteogenesis

NASA Astrophysics Data System (ADS)

Gorczynski, Reginald M.; Gorczynski, Christopher P.; Gorczynski, Laura Y.; Hu, Jiang; Lu, Jin; Manuel, Justin; Lee, Lydia

2005-05-01

We examined expression of genes associated with cytokine production, and genes implicated in regulating bone metabolism, in bone stromal and osteoblast cells incubated under standard ground conditions and under conditions of neutral buoyancy, and in the presence/absence of serum from normal or sleep-deprived mice. We observed a clear interaction between these two conditions (exposure to neutral buoyancy and serum stimulation) in promoting enhanced osteoclastogenesis. Both conditions independently altered expression of a number of cytokines implicated in the regulation of bone metabolism. However, using stromal cells from IL-1 and TNF α cytokine r KO mice, we concluded that the increased bone loss under microgravity conditions was not primarily cytokine mediated.

Insulin-like growth factor I has independent effects on bone matrix formation and cell replication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hock, J.M.; Centrella, M.; Canalis, E.

1988-01-01

The effects of insulin-like growth factor-I (IGF-I) and insulin on bone matrix synthesis and bone cell replication were studied in cultured 21-day-old fetal rat calvariae. Histomorphometry techniques were developed to measure the incorporation of (2,3-/sup 3/H)proline and (methyl-/sup 3/H)thymidine into bone matrix and bone cell nuclei, respectively, using autoradiographs of sagittal sections of calvariae cultured with IGF-I, insulin, or vehicle for up to 96 h. To confirm an effect on bone formation, IGF-I was also studied for its effects on (/sup 3/H)proline incorporation into collagenase-digestible protein (CDP) and noncollagen protein and on (/sup 3/H)thymidine incorporation into acid-precipitable material (DNA). IGF-Imore » at 10(-9)-10(-7) M significantly increased the rate of bone matrix apposition and CDP after 24 h by 45-50% and increased cell labeling by 8-fold in the osteoprogenitor cell zone, by 4-fold in the osteoblast cell zone, and by 2-fold in the periosteal fibroblast zone. Insulin at 10(-9)-10(-6) M also increased matrix apposition rate and CDP by 40-50%, but increased cell labeling by 2-fold only at a concentration of 10(-7) M or higher and then only in the osteoprogenitor cell zone. When hydroxyurea was added to IGF-I-treated bones, the effects of IGF-I on DNA synthesis were abolished, but the increase in bone matrix apposition induced by IGF-I was only partly diminished. In conclusion, IGF-I stimulates matrix synthesis in calvariae, an effect that is partly, although not completely, dependent on its stimulatory effect on DNA synthesis.« less

Enhanced human bone marrow mesenchymal stem cell functions on cathodic arc plasma-treated titanium.

PubMed

Zhu, Wei; Teel, George; O'Brien, Christopher M; Zhuang, Taisen; Keidar, Michael; Zhang, Lijie Grace

2015-01-01

Surface modification of titanium for use in orthopedics has been explored for years; however, an ideal method of integrating titanium with native bone is still required to this day. Since human bone cells directly interact with nanostructured extracellular matrices, one of the most promising methods of improving titanium's osseointegration involves inducing bio-mimetic nanotopography to enhance cell-implant interaction. In this regard, we explored an approach to functionalize the surface of titanium by depositing a thin film of textured titanium nanoparticles via a cathodic arc discharge plasma. The aim is to improve human bone marrow mesenchymal stem cell (MSC) attachment and differentiation and to reduce deleterious effects of more complex surface modification methods. Surface functionalization was analyzed by scanning electron microscopy, atomic force microscopy, contact angle testing, and specific protein adsorption. Scanning electron microscopy and atomic force microscopy examination demonstrate the deposition of titanium nanoparticles and the surface roughness change after coating. The specific fibronectin adsorption was enhanced on the modified titanium surface that associates with the improved hydrophilicity. MSC adhesion and proliferation were significantly promoted on the nanocoated surface. More importantly, compared to bare titanium, greater production of total protein, deposition of calcium mineral, and synthesis of alkaline phosphatase were observed from MSCs on nanocoated titanium after 21 days. The method described herein presents a promising alternative method for inducing more cell favorable nanosurface for improved orthopedic applications.

Novel peptide-based platform for the dual presentation of biologically active peptide motifs on biomaterials.

PubMed

Mas-Moruno, Carlos; Fraioli, Roberta; Albericio, Fernando; Manero, José María; Gil, F Javier

2014-05-14

Biofunctionalization of metallic materials with cell adhesive molecules derived from the extracellular matrix is a feasible approach to improve cell-material interactions and enhance the biointegration of implant materials (e.g., osseointegration of bone implants). However, classical biomimetic strategies may prove insufficient to elicit complex and multiple biological signals required in the processes of tissue regeneration. Thus, newer strategies are focusing on installing multifunctionality on biomaterials. In this work, we introduce a novel peptide-based divalent platform with the capacity to simultaneously present distinct bioactive peptide motifs in a chemically controlled fashion. As a proof of concept, the integrin-binding sequences RGD and PHSRN were selected and introduced in the platform. The biofunctionalization of titanium with this platform showed a positive trend towards increased numbers of cell attachment, and statistically higher values of spreading and proliferation of osteoblast-like cells compared to control noncoated samples. Moreover, it displayed statistically comparable or improved cell responses compared to samples coated with the single peptides or with an equimolar mixture of the two motifs. Osteoblast-like cells produced higher levels of alkaline phosphatase on surfaces functionalized with the platform than on control titanium; however, these values were not statistically significant. This study demonstrates that these peptidic structures are versatile tools to convey multiple biofunctionality to biomaterials in a chemically defined manner.

Explorations in the application of nanotechnology to improve the mechanical properties of composite materials

NASA Astrophysics Data System (ADS)

Yang, Cheng

2007-12-01

This thesis presents the research achievements on the design, preparation, characterization, and analysis of a series of composite materials. By studying the interface interaction of the composite materials using nanotechnology, we developed composite materials that achieve satisfactory mechanical properties in two classes of materials. Durable press (DP) natural textiles are important consumer products usually achieved by erosslinking the molecules in the textiles to achieve long-term wrinkle resistance, which, however, also leads to the simultaneous significant drop of mechanical properties. Herein, a series of polymeric nanoparticl es were investigated, the application of as little as ˜0.14 wt% addition of the nanoparticles improved the mechanical property of the DP cotton fabric by 56% in tearing resistance and 100% in abrasion resistance; the loss in recovery angle is negligible. The author also studied the enzyme-triggered DP treatments of silk fabrics, as a green process method. After the treatment of enzymes, excellent DP property was achieved with improved strain property. Injectable calcium phosphate powder containing acrylic bone cements are widely used in orthopedic surgery to fix artificial prostheses. However, the bending strength is still unsatisfactory. The author modified the surface of the strontium (Sr) containing hydroxyapatite (HA) filler powders with acrylolpamidronate in order to improve the overall mechanical performance of the bone cement composites. By adding 0.25 wt% of acrylolpamidronate to the Sr-HA nanopowders, more than 19% of the bending strength and more than 23% compression strength of the Sr-HA bone cement were improved. Biological evaluations revealed that these bone cement composites were biocompatible and bioactive in cell culture. The results obtained in this thesis work show an effective method to significantly enhance the mechanical properties of composite materials. Different from other available methods, by developing a new series of chemical compounds and nanoparticles, we successfully bound them to the surface or to the constitutional components of the materials through covalent bond. The treatment can enhance and modulate the interface-bonding of the filler materials and enhances the mechanical property of the surface through grafting a thin nano-layer. Since only surface reaction is involved, very small amount of the new material is needed, and the treatment can be readily integrated to the existing processes. The work is instructive in modifying available composite materials to acquire ultra-high mechanical performance.

A Comparative Evaluation of the Mechanical Properties of Two Calcium Phosphate/Collagen Composite Materials and Their Osteogenic Effects on Adipose-Derived Stem Cells

PubMed Central

Li, Qing; Wang, Tong; Zhang, Gui-feng; Yu, Xin; Zhang, Jing; Zhou, Gang; Tang, Zhi-hui

2016-01-01

Adipose-derived stem cells (ADSCs) are ideal seed cells for use in bone tissue engineering and they have many advantages over other stem cells. In this study, two kinds of calcium phosphate/collagen composite scaffolds were prepared and their effects on the proliferation and osteogenic differentiation of ADSCs were investigated. The hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composite scaffolds (HTPSs), which have an additional β-tricalcium phosphate, resulted in better proliferation of ADSCs and showed osteogenesis-promoting effects. Therefore, such composite scaffolds, in combination with ADSCs or on their own, would be promising for use in bone regeneration and potential clinical therapy for bone defects. PMID:27239204

Histomorphometric and immunohistochemical analysis of human maxillary sinus-floor augmentation using porous β-tricalcium phosphate for dental implant treatment.

PubMed

Miyamoto, Shinji; Shinmyouzu, Kouhei; Miyamoto, Ikuya; Takeshita, Kenji; Terada, Toshihisa; Takahashi, Tetsu

2013-08-01

This study utilized the constitution and expression of Runx2/Cbfa1 to conduct 6-month-post-operation histomorphometrical and histochemical analysis of osteocalcin in bone regeneration following sinus-floor augmentation procedures using β-tricalcium phosphate (β-TCP) and autogenous cortical bone. Thirteen sinuses of nine patients were treated with sinus-floor augmentation using 50% β-TCP and 50% autogenous cancellous bone harvested from the ramus of the mandible. Biopsies of augmented sinuses were taken at 6 months for histomorphometric and immunohistochemical measurements. Runx2/Cbfa1- and osteocalcin-positive cells were found around TCP particles and on the bone surface. Approximately 60% of cells found around TCP particles stained positive for Runx2/Cbfa1. Fewer cells stained positive for osteocalcin. These positive cells decreased apically with increasing vertical distance from the maxillary bone surface. Histomorphometric analysis showed that the augmented site close to residual bone and periosteum contained approximately 42% bony tissue and 42% soft connective tissue, and the remaining 16% consisted of TCP particles. On the other hand, the augmented bone far from residual bone and periosteum contained 35% bony tissue and 50% soft connective tissue. Our data suggest that TCP particles attract osteoprogenitor cells that migrate into the interconnecting micropores of the bone-substitute material by 6 months. The augmented site close to residual bone contained a higher proportion of bony tissue and a lower proportion of soft connective tissue than did the augmented site far from residual bone. © 2012 John Wiley & Sons A/S.

Microbe-Induced Inflammatory Signals Triggering Acquired Bone Marrow Failure Syndromes.

PubMed

Espinoza, J Luis; Kotecha, Ritesh; Nakao, Shinji

2017-01-01

Acquired bone marrow failure syndromes encompass a unique set of disorders characterized by a reduction in the effective production of mature cells by the bone marrow (BM). In the majority of cases, these syndromes are the result of the immune-mediated destruction of hematopoietic stem cells or their progenitors at various stages of differentiation. Microbial infection has also been associated with hematopoietic stem cell injury and may lead to associated transient or persistent BM failure, and recent evidence has highlighted the potential impact of commensal microbes and their metabolites on hematopoiesis. We summarize the interactions between microorganisms and the host immune system and emphasize how they may impact the development of acquired BM failure.

Microbe-Induced Inflammatory Signals Triggering Acquired Bone Marrow Failure Syndromes

PubMed Central

Espinoza, J. Luis; Kotecha, Ritesh; Nakao, Shinji

2017-01-01

Acquired bone marrow failure syndromes encompass a unique set of disorders characterized by a reduction in the effective production of mature cells by the bone marrow (BM). In the majority of cases, these syndromes are the result of the immune-mediated destruction of hematopoietic stem cells or their progenitors at various stages of differentiation. Microbial infection has also been associated with hematopoietic stem cell injury and may lead to associated transient or persistent BM failure, and recent evidence has highlighted the potential impact of commensal microbes and their metabolites on hematopoiesis. We summarize the interactions between microorganisms and the host immune system and emphasize how they may impact the development of acquired BM failure. PMID:28286502

Mesenchymal stem cells induce dermal fibroblast responses to injury

PubMed Central

Smith, Andria N.; Willis, Elise; Chan, Vincent T.; Muffley, Lara A.; Isik, F. Frank; Gibran, Nicole S.; Hocking, Anne M.

2009-01-01

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury. PMID:19666021

Ex Vivo Growth of Bioengineered Ligaments and Other Tissues

NASA Technical Reports Server (NTRS)

Altman, Gregory; Kaplan, David L.; Martin, Ivan; Vunjak-Novakovic, Gordana

2005-01-01

A method of growing bioengineered tissues for use in surgical replacement of damaged anterior cruciate ligaments has been invented. An anterior cruciate ligament is one of two ligaments (the other being the posterior cruciate ligament) that cross in the middle of a knee joint and act to prevent the bones in the knee from sliding forward and backward relative to each other. Anterior cruciate ligaments are frequently torn in sports injuries and traffic accidents, resulting in pain and severe limitations on mobility. By making it possible to grow replacement anterior cruciate ligaments that structurally and functionally resemble natural ones more closely than do totally synthetic replacements, the method could create new opportunities for full or nearly full restoration of functionality in injured knees. The method is also adaptable to the growth of bioengineered replacements for other ligaments (e.g., other knee ligaments as well as those in the hands, wrists, and elbows) and to the production of tissues other than ligaments, including cartilage, bones, muscles, and blood vessels. The method is based on the finding that the histomorphological properties of a bioengineered tissue grown in vitro from pluripotent cells within a matrix are affected by the direct application of mechanical force to the matrix during growth generation. This finding provides important new insights into the relationships among mechanical stress, biochemical and cell-immobilization methods, and cell differentiation, and is applicable to the production of the variety of tissues mentioned above. Moreover, this finding can be generalized to nonmechanical (e.g., chemical and electromagnetic) stimuli that are experienced in vivo by tissues of interest and, hence, the method can be modified to incorporate such stimuli in the ex vivo growth of replacements for the various tissues mentioned above. In this method, a three-dimensional matrix made of a suitable material is seeded with pluripotent stem cells. The patient s bone-marrow stromal cells are preferably used as the pluripotent cells in this method. Suitable matrix materials are materials to which cells can adhere for example, collagen type I. The seeded matrix is attached to anchors at opposite ends and then the cells in the matrix are cultured under conditions appropriate for the growth and regeneration of cells. Suitable anchor materials are materials to which the matrix can attach; examples include demineralized bone and Goinopra coral that has been treated to convert its calcium carbonate to calcium phosphate.

Evaluation of the In Vitro Cytotoxicity of Crosslinked Biomaterials

PubMed Central

Wang, Martha O.; Etheridge, Julie M.; Thompson, Joshua A.; Vorwald, Charlotte E.; Dean, David; Fisher, John P.

2013-01-01

This study evaluated the in vitro cytotoxicity of poly(propylene fumarate) (PPF). PPF is an aliphatic biodegradable polymer that has been well characterized for use in bone tissue engineering scaffolds. Four different cell types, human mesenchymal stem cells (hMSC), fibroblasts (L929), pre-osteoblasts (MC3T3), and canine mesenchymal stem cells (cMSC), were used to evaluate the cytotoxicity of PPF. These cell types represent the tissues that PPF would interact with in vivo as a bone tissue scaffold. The sol fraction of the PPF films was measured and then utilized to estimate crosslinking density. Cytotoxicity was evaluated using XTT assay and fluorescence imaging. Results showed that PPF supported similar cell metabolic activities of hMSC, L929, MC3T3 and cMSC compared to the non-cytotoxic control, high density polyethylene (HDPE) and were statistically different than those cultured with the cytotoxic control, a polyurethane film containing 0.1% zinc diethyldithiocarbamate (ZCF). Results showed differing cellular responses to ZCF, the cytotoxic control. The L929 cells had the lowest cell metabolic activity levels after exposure to ZCF compared to the cell metabolic activity levels of the MC3T3, hMSC or cMSC cells. Qualitative verification of the results using fluorescence imaging demonstrated no change in cell morphology, vacuolization, or detachment when cultured with PPF compared to HDPE or blank media cultures. Overall the cytotoxicity response of the cells to PPF was demonstrated to be similar to the cytotoxic response of cells to known non-cytotoxic materials (HDPE). PMID:23627804

Investigation of biomineralization by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Fatscher, Robert William

Biomineralization is a process in which living organism grow composite materials consisting of inorganic and organic materials. This produces a composite material consisting of both inorganic and organic components, with superior mechanical properties. In the human body bone and dentin are both examples of biominerals. In this research Raman spectroscopy was used to characterize dentin from mice and human teeth, to determine composition. In the mouse tooth samples areas of irregular dentin were found, along the inside of the tooth, to be in the process of mineralization. By analyzing the samples along these areas we were able to determine the composition of dentin and track how it changed in these area. By analysis of the mineral to matrix ratio the areas of irregular dentin were determined to have less mineral present. Observations of other organic components and collagen in increased concentrations in this area suggested these area were in the process of biomineralization. The understanding of the structure of dentin and its biomineralization process is of crucial importance when trying reproduce dentin. Scientists and engineers are able to produce dentin minerals in vitro by culturing various dental stem cells. The ability to create dentin mineral from cells could lead to methods of repairing dentin in patients, or even lead to the creation of a completely engineered tooth. While dentin-like materials can be produced in a laboratory environment, analysis and comparison of the composition of these materials must be performed to ensure the mineral produced is consistent with dentin. Mineralized nodules from six different dental stem cell lines were cultured to produce a mineralized deposit. Utilizing Raman spectroscopy, we were able to determine cell source dependent differences in a variety of dental stem cells, and compare the mineral produced to native dentin. Orthopedic implants are implants used to replace damaged bone, examples include knee, hip and dental implants. These implants are designed to osteointegrate with the native healthy tissues in order to create a functionally stable and structural interface. Biomaterials such as hydroxyapatite and titania are known to increase the rate of bone regeneration in vivo.1 By accelerating the early response of bone forming cells to these implants, better fixation is achieved between the implant and the bone, shortening recovery times and increasing the viability of these implants. In the last part of this research an investigation of osteoblasts cultured at 14 days on five different heat-treated titania substrates was investigated by Raman spectroscopy, in order to observe the initial cellular response to the titania substrates. The heat-treatment of titania changes the amount of oxygen on it's surface which in turn effects the surface energy. A change in the surface energy of a material will affect the cellular response, by culturing cells on various heat-treated titania substrates a relationship between the surface energy and cellular response can be investigated. A faster cellular response would lead to an increased rate of bone regeneration shortening healing times and allowing for better fixation of the implant.

Gelatin freeze casting of biomimetic titanium alloy with anisotropic and gradient pore structure.

PubMed

Zhang, Lei; Le Coz-Botrel, Ronan; Beddoes, Charlotte; Sjöström, Terje; Su, Bo

2017-01-17

Titanium is a material commonly used for dental and orthopaedic implants. However, due to large differences in properties between the titanium metal and the natural bone, stress shielding has been observed in the surrounding area, resulting in bone atrophy, and thus has raised concerns of the use of this material. Ideally implant materials should possess similar properties to the surrounding tissues in order to distribute the load as the joint would naturally, while also possessing a similar porous structure to the bone to enable interaction with the surrounding material. In this paper we report the formation of aligned porous titanium alloy scaffolds with the use of unidirectional freeze casting with a temperature gradient. The resulting scaffolds had a dense bottom part with sufficient strength for loading, while the top part remaining porous in order to allow bone growth in the scaffold and fully integrating with the surrounding tissue. The anisotropic nature of the pores within the titanium alloy samples were observed via micro computed tomography, where a gradient structure similar to bone was observed. The compressive strength of the fabricated scaffolds was found to be up to 427 MPa when measured with the pores aligned with the applied load, depending on the pore density. This is within the range of cortical bone.

Supercritical carbon dioxide-processed resorbable polymer nanocomposites for bone graft substitute applications

NASA Astrophysics Data System (ADS)

Baker, Kevin C.

Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the requisite porous morphology. As such, porous resorbable polymers are often reinforced with filler materials. In the presented work, we describe the use of supercritical carbon dioxide (scCO2) processing to create porous resorbable polymeric constructs reinforced by nanostructured, organically modified Montmorillonite clay (nanoclay). scCO2 processing simultaneously disperses the nanoclay throughout the polymeric matrix, while imparting a porous morphology to the construct conducive to facilitating cellular infiltration and neoangiogenesis, which are necessary components of bone growth. With the addition of as little as 2.5wt% of nanoclay, the compressive strength of the constructs nearly doubles putting them on par with human cortico-cancellous bone. Rheological measurements indicate that the dominant mode of reinforcement of the nanocomposite constructs is the restriction of polymer chain mobility. This restriction is a function of the positive interaction between polymer chains and the nanoclay. In vivo inflammation studies indicate biocompatibility of the constructs. Ectopic osteogenesis assays have determined that the scCO2-processed nanocomposites are capable of supporting growth-factor induced bone formation. scCO 2-processed resorbable polymer nanocomposites composed of resorbable polymers and nanocaly exhibit physical, mechanical and biologic properties that make them excellent candidate materials for structural bone graft substitute applications.

Vertebral osteoporosis: perfused animal cadaver model for testing new vertebroplastic agents.

PubMed

Hoell, Thomas; Huschak, Gerald; Beier, Andre; Holzhausen, Hans-Juergen; Meisel, Hans-Joerg; Emmrich, Frank

2010-12-01

Experimental study. It was aimed to establish a cadaver model to imitate osteoporotic perfused vertebral bone and to allow for transpedicular transfer of bone cement and various new materials into vertebrae. The model was perfused to simulate vertebroplasty in the presence of transvertebral blood flow. The injection of bone cement into vertebrae bears the risk of irreversible discharge of material into the venous system of the spinal canal. The bovine cadaver model studied allows visual studies of material distribution in a vertebral bone, the potential spill-out of material, and quantification of washout and disintegration phenomena. Thoracic and lumbar vertebrae from 1-year-old calves were cut transversally into 5 mm slices, macerated, and decalcified. The softened bone slices were compressed between 2 transparent plastic discs. A standard vertebroplasty cannula (outer diameter 3.5 mm, inner diameter 2.5 mm) was inserted into the vertebral body via the pedicle to transfer the different vertebroplasty materials. Arterial blood flow was simulated by means of liquid irrigation via 2 needles in the ventral part of the vertebral body slice. Metal powder was mixed with the solution to indicate the blood flow in the bone. The model was evaluated with the vertebroplasty cement polymethylmethacrylate. The model permitted visualization of the insertion and distribution of vertebroplasty materials. Liquid bone cement was effused into the spinal canal as in the clinical situation. Higher modulus cement acted in the same way as in clinical vertebroplasty. Rigid vertebroplasty agents led to trabecular fractures and stable mechanical interactions with the bone and eventually moved dorsal bone fragments into the spinal canal. Sedimentation of the metal powder indicated regions of perfusion. The model simulated the clinical behavior of liquid and higher modulus vertebroplasty agents in the presence of blood flow. It enabled safe ex vivo testing of the mechanical and physical properties of alternative vertebroplasty materials under flow conditions.

Safety Evaluation of a Bioglass–Polylactic Acid Composite Scaffold Seeded with Progenitor Cells in a Rat Skull Critical-Size Bone Defect

PubMed Central

El-Kady, Abeer M.; Arbid, Mahmoud S.; Abd El-Hady, Bothaina M.; Marzi, Ingo; Seebach, Caroline

2014-01-01

Treating large bone defects represents a major challenge in traumatic and orthopedic surgery. Bone tissue engineering provides a promising therapeutic option to improve the local bone healing response. In the present study tissue biocompatibility, systemic toxicity and tumorigenicity of a newly developed composite material consisting of polylactic acid (PLA) and 20% or 40% bioglass (BG20 and BG40), respectively, were analyzed. These materials were seeded with mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) and tested in a rat calvarial critical size defect model for 3 months and compared to a scaffold consisting only of PLA. Serum was analyzed for organ damage markers such as GOT and creatinine. Leukocyte count, temperature and free radical indicators were measured to determine the degree of systemic inflammation. Possible tumor occurrence was assessed macroscopically and histologically in slides of liver, kidney and spleen. Furthermore, the concentrations of serum malondialdehyde (MDA) and sodium oxide dismutase (SOD) were assessed as indicators of tumor progression. Qualitative tissue response towards the implants and new bone mass formation was histologically investigated. BG20 and BG40, with or without progenitor cells, did not cause organ damage, long-term systemic inflammatory reactions or tumor formation. BG20 and BG40 supported bone formation, which was further enhanced in the presence of EPCs and MSCs. This investigation reflects good biocompatibility of the biomaterials BG20 and BG40 and provides evidence that additionally seeding EPCs and MSCs onto the scaffold does not induce tumor formation. PMID:24498345

Monocytes Induce STAT3 Activation in Human Mesenchymal Stem Cells to Promote Osteoblast Formation

PubMed Central

Nicolaidou, Vicky; Wong, Mei Mei; Redpath, Andia N.; Ersek, Adel; Baban, Dilair F.; Williams, Lynn M.; Cope, Andrew P.; Horwood, Nicole J.

2012-01-01

A major therapeutic challenge is how to replace bone once it is lost. Bone loss is a characteristic of chronic inflammatory and degenerative diseases such as rheumatoid arthritis and osteoporosis. Cells and cytokines of the immune system are known to regulate bone turnover by controlling the differentiation and activity of osteoclasts, the bone resorbing cells. However, less is known about the regulation of osteoblasts (OB), the bone forming cells. This study aimed to investigate whether immune cells also regulate OB differentiation. Using in vitro cell cultures of human bone marrow-derived mesenchymal stem cells (MSC), it was shown that monocytes/macrophages potently induced MSC differentiation into OBs. This was evident by increased alkaline phosphatase (ALP) after 7 days and the formation of mineralised bone nodules at 21 days. This monocyte-induced osteogenic effect was mediated by cell contact with MSCs leading to the production of soluble factor(s) by the monocytes. As a consequence of these interactions we observed a rapid activation of STAT3 in the MSCs. Gene profiling of STAT3 constitutively active (STAT3C) infected MSCs using Illumina whole human genome arrays showed that Runx2 and ALP were up-regulated whilst DKK1 was down-regulated in response to STAT3 signalling. STAT3C also led to the up-regulation of the oncostatin M (OSM) and LIF receptors. In the co-cultures, OSM that was produced by monocytes activated STAT3 in MSCs, and neutralising antibodies to OSM reduced ALP by 50%. These data indicate that OSM, in conjunction with other mediators, can drive MSC differentiation into OB. This study establishes a role for monocyte/macrophages as critical regulators of osteogenic differentiation via OSM production and the induction of STAT3 signalling in MSCs. Inducing the local activation of STAT3 in bone cells may be a valuable tool to increase bone formation in osteoporosis and arthritis, and in localised bone remodelling during fracture repair. PMID:22802946

Hard tissue remodeling using biofabricated coralline biomaterials.

PubMed

Vago, Razi; Plotquin, Daniel; Bunin, Alex; Sinelnikov, Igor; Atar, Dan; Itzhak, David

2002-01-04

Biotechnical and biomedical approaches were combined in an attempt to identify potential uses of biofabricated marine carbonate materials in biomedical applications, particularly as biomatrices for remodeling bone and cartilage tissue. After grafting, it is desirable for bone ingrowth to proceed as quickly as possible because the strength of the implanted region depends on a good mechanical bond forming between the implant and surrounding regions in the body. Ingrowth can take place as a result of growth of tissue and cells into the implanted porous material, or it may be promoted by transplanting cells seeded onto such a material. The rate at which ingrowth occurs is dependent on many factors, including pore size and the interconnectivity of the implanted structure. In vivo graftings into osteochondral defects demonstrated that our biofabricated porous material is highly biocompatible with cartilage and bone tissue. The biofabricated matrix was well incorporated into the biphasic osteochondral area. Resorption was followed by bone and cartilage formation, and after 4 months, the biomaterial had been replaced by new tissue. Ossification was induced and enhanced without introduction of additional factors. We believe that this is the first time that such biofabricated materials have been used for biomedical purposes. In face of the obvious environmental disadvantages of harvesting from limited natural resources, we propose the use of bioengineered coralline and other materials such as those cultured by our group under field and laboratory conditions as a possible biomatrix for hard tissue remodeling.

Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials.

PubMed

Montalbano, Giorgia; Fiorilli, Sonia; Caneschi, Andrea; Vitale-Brovarone, Chiara

2018-04-28

Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able to perform a sol-gel transition under physiological conditions. Field emission scanning electron microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate deposition. The high-water content promoted the strontium ion release from the embedded glass particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the suspension printability was assessed by means of rheological studies and preliminary extrusion tests, showing shear thinning and fast material recovery upon deposition. In conclusion, the reported results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone tissue engineering have been developed.

Hydrogel-embedded nanocrystalline hydroxyapatite granules (elastic blocks) based on a cross-linked polyvinylpyrrolidone as bone grafting substitute in a rat tibia model.

PubMed

Dau, Michael; Ganz, Cornelia; Zaage, Franziska; Frerich, Bernhard; Gerber, Thomas

2017-01-01

The aim of this study was to examine the in vivo characteristics and levels of integration and degradation of a ready-to-use bone grafting block with elastic properties (elastic block) for the use in surgery. Thirty-six male Wistar rats underwent surgical creation of a well-defined bone defect in the tibia. All created defects - one per animal - were filled with an unsintered nanocrystalline hydroxyapatite embedded either with a non-cross-linked hydrogel carrier (CONT, n=18) or a cross-linked hydrogel carrier (elastic block [EB], n=18) based on polyvinylpyrrolidone (PVP) and silica sol, respectively. The animals were killed after 12 (n=12), 21 (n=12) and 63 days (n=12). The bone formation and defect healing were quantified by histomorphometric measurements made in paraffin sections. Additionally, immunohistochemical (tartrate-resistant acid phosphatase [TRAP] and alkaline phosphatase [aP]), antibody-based examinations (CD68) and energy-dispersive x-ray scattering measurements of silica atom concentration were carried out. A larger remaining bone defect area overall was observed in EB after 12 days and 21 days. After 63 days, similar areas of remaining bone defects were found. The amount of the remaining carrier material in EB overall was higher at all times. In CONT no residual carrier material was found at 12 days and later. CD68 analyses showed significantly lower level of CD68-positive marked cells after 21 days in CONT, and nonsignificant differences at 12 and 63 days, respectively. Additionally, a significantly higher level of aP-positive marked cells was observed in CONT after 12 days. Later on, the levels of aP-positive marked cells were slightly higher in EB (21 and 63 days). Furthermore, no significant differences regarding the level of TRAP-positive marked cells in each group were observed. The bone substitute (EB) with the cross-linked PVP-based hydrogel carrier leads at the beginning to a higher amount of remaining carrier material and remaining bone substitute. This delayed degradation is supposed to be the reason for the observed lower level of bone remodeling and is caused by the irradiation changes (cross links) in the structure in PVP.

The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

PubMed

Bagherifard, Sara; Hickey, Daniel J; de Luca, Alba C; Malheiro, Vera N; Markaki, Athina E; Guagliano, Mario; Webster, Thomas J

2015-12-01

Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria. The treated 316L stainless steel surfaces were first investigated in terms of surface topography, grain size, hardness, wettability and residual stresses. The effects of the induced surface modifications were then separately studied in terms of cell morphology, adhesion and proliferation of primary human osteoblasts (bone forming cells) as well as the adhesion of multiple bacteria strains, specifically Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and ampicillin-resistant Escherichia coli. The results indicated a significant enhancement in surface work hardening and compressive residual stresses, maintenance of osteoblast adhesion and proliferation as well as a remarkable decrease in the adhesion and growth of gram-positive bacteria (S. aureus and S. epidermidis) compared to non-treated and conventionally shot peened samples. Impressively, the decrease in bacteria adhesion and growth was achieved without the use of antibiotics, for which bacteria can develop a resistance towards anyway. By slightly grinding the surface of severe shot peened samples to remove differences in nanoscale surface roughness, the effects of varying substrate grain size were separated from those of varying surface roughness. The expression of vinculin focal adhesions from osteoblasts was found to be singularly and inversely related to grain size, whereas the attachment of gram-positive bacteria (S. aureus and S. epidermidis) decreased with increasing nanoscale surface roughness, and was not affected by grain refinement. Ultimately, this study demonstrated the advantages of the proposed shot peening treatment to produce multifunctional 316L stainless steel materials for improved implant functions without necessitating the use of drugs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Materials and scaffolds in medical 3D printing and bioprinting in the context of bone regeneration.

PubMed

Heller, Martin; Bauer, Heide-Katharina; Goetze, Elisabeth; Gielisch, Matthias; Ozbolat, Ibrahim T; Moncal, Kazim K; Rizk, Elias; Seitz, Hermann; Gelinsky, Michael; Schröder, Heinz C; Wang, Xiaohong H; Müller, Werner E G; Al-Nawas, Bilal

The structural and functional repair of lost bone is still one of the biggest challenges in regenerative medicine. In many cases, autologous bone is used for the reconstruction of bone tissue; however, the availability of autologous material is limited, which always means additional stress to the patient. Due to this, more and more frequently various biocompatible materials are being used instead for bone augmentation. In this context, in order to ensure the structural function of the bone, scaffolds are implanted and fixed into the bone defect, depending on the medical indication. Nevertheless, for the surgeon, every individual clinical condition in which standardized scaffolds have to be aligned is challenging, and in many cases the alignment is not possible without limitations. Therefore, in the last decades, 3D printing (3DP) or additive manufacturing (AM) of scaffolds has become one of the most innovative approaches in surgery to individualize and improve the treatment of patients. Numerous biocompatible materials are available for 3DP, and various printing techniques can be applied, depending on the process conditions of these materials. Besides these conventional printing techniques, another promising approach in the context of medical AM is 3D bioprinting, a technique which makes it possible to print human cells embedded in special carrier substances to generate functional tissues. Even the direct printing into bone defects or lesions becomes possible. 3DP is already improving the treatment of patients, and has the potential to revolutionize regenerative medicine in future.

Interactions of Human Endothelial and Multipotent Mesenchymal Stem Cells in Cocultures

PubMed Central

Ern, Christina; Krump-Konvalinkova, Vera; Docheva, Denitsa; Schindler, Stefanie; Rossmann, Oliver; Böcker, Wolfgang; Mutschler, Wolf; Schieker, Matthias

2010-01-01

Current strategies for tissue engineering of bone rely on the implantation of scaffolds, colonized with human mesenchymal stem cells (hMSC), into a recipient. A major limitation is the lack of blood vessels. One approach to enhance the scaffold vascularisation is to supply the scaffolds with endothelial cells (EC). The main goal of this study was to establish a coculture system of hMSC and EC for the purposes of bone tissue engineering. Therefore, the cell behaviour, proliferation and differentiation capacity in various cell culture media as well as cell interactions in the cocultures were evaluated. The differentiation capacity of hMSC along osteogenic, chondrogenic, and adipogenic lineage was impaired in EC medium while in a mixed EC and hMSC media, hMSC maintained osteogenic differentiation. In order to identify and trace EC in the cocultures, EC were transduced with eGFP. Using time-lapse imaging, we observed that hMSC and EC actively migrated towards cells of their own type and formed separate clusters in long term cocultures. The scarcity of hMSC and EC contacts in the cocultures suggest the influence of growth factor-mediated cell interactions and points to the necessity of further optimization of the coculture conditions. PMID:21625373

Effect of bone sialoprotein and collagen coating on cell attachment to TICER and pure titanium implant surfaces.

PubMed

Graf, H-L; Stoeva, S; Armbruster, F P; Neuhaus, J; Hilbig, H

2008-07-01

To improve integration between implants and biological tissues, this study compared bone sialoprotein (BSP) as a surface-coating material against the major organic and inorganic components of bone, collagen type I and hydroxyapatite (TICER). The expression of osteocalcin, osteonectin and transforming growth factor ss was evaluated using immunohistochemical staining procedures. The distribution patterns of osteoblasts on the surface of pure titanium with a smooth machined surface and a rough surface (TICER) were determined by image processing using confocal laser scanning microscopy. The results compared to uncoated control materials showed that, at all times investigated, the number of cells on the surface of the TICER and pure titanium samples differed significantly (P<0.1), demonstrating the superiority of TICER over pure titanium in this respect. For pure titanium implants, collagen-precoated surfaces were not beneficial for the attachment of bone-derived cells with the exception of day 3 in vitro (P<0.01). BSP-precoated implant surfaces displayed non-significantly higher numbers of settled cells. BSP-precoated implant surfaces were beneficial for osteoinduction as revealed by osteocalcin and osteonectin expression. BSP precoating of the rough TICER implant surface enhanced the osteoinductive effect much more than did collagen precoating. These results contribute to the consideration of at least two distinct pathways of osseointegration.

Optimizing Biomaterials for Tissue Engineering Human Bone Using Mesenchymal Stem Cells.

PubMed

Weinand, Christian; Neville, Craig M; Weinberg, Eli; Tabata, Yasuhiko; Vacanti, Joseph P

2016-03-01

Adequate biomaterials for tissue engineering bone and replacement of bone in clinical settings are still being developed. Previously, the combination of mesenchymal stem cells in hydrogels and calcium-based biomaterials in both in vitro and in vivo experiments has shown promising results. However, results may be optimized by careful selection of the material combination. β-Tricalcium phosphate scaffolds were three-dimensionally printed with five different hydrogels: collagen I, gelatin, fibrin glue, alginate, and Pluronic F-127. The scaffolds had eight channels, running throughout the entire scaffold, and macropores. Mesenchymal stem cells (2 × 10) were mixed with each hydrogel, and cell/hydrogel mixes were dispersed onto the corresponding β-tricalcium phosphate/hydrogel scaffold and cultured under dynamic-oscillating conditions for 6 weeks. Specimens were harvested at 1, 2, 4, and 6 weeks and evaluated histologically, radiologically, biomechanically and, at 6 weeks, for expression of bone-specific proteins by reverse-transcriptase polymerase chain reaction. Statistical correlation analysis was performed between radiologic densities in Hounsfield units and biomechanical stiffness. Collagen I samples had superior bone formation at 6 weeks as demonstrated by volume computed tomographic scanning, with densities of 300 HU, similar to native bone, and the highest compression values. Bone specificity of new tissue was confirmed histologically and by the expression of alkaline phosphatase, osteonectin, osteopontin, and osteocalcin. The bone density correlated closely with histologic and biomechanical testing results. Bone formation is supported best by β-tricalcium phosphate/collagen I hydrogel and mesenchymal stem cells in collagen I hydrogel. Therapeutic, V.

Cellularizing hydrogel-based scaffolds to repair bone tissue: How to create a physiologically relevant micro-environment?

PubMed Central

Maisani, Mathieu; Pezzoli, Daniele; Chassande, Olivier; Mantovani, Diego

2017-01-01

Tissue engineering is a promising alternative to autografts or allografts for the regeneration of large bone defects. Cell-free biomaterials with different degrees of sophistication can be used for several therapeutic indications, to stimulate bone repair by the host tissue. However, when osteoprogenitors are not available in the damaged tissue, exogenous cells with an osteoblast differentiation potential must be provided. These cells should have the capacity to colonize the defect and to participate in the building of new bone tissue. To achieve this goal, cells must survive, remain in the defect site, eventually proliferate, and differentiate into mature osteoblasts. A critical issue for these engrafted cells is to be fed by oxygen and nutrients: the transient absence of a vascular network upon implantation is a major challenge for cells to survive in the site of implantation, and different strategies can be followed to promote cell survival under poor oxygen and nutrient supply and to promote rapid vascularization of the defect area. These strategies involve the use of scaffolds designed to create the appropriate micro-environment for cells to survive, proliferate, and differentiate in vitro and in vivo. Hydrogels are an eclectic class of materials that can be easily cellularized and provide effective, minimally invasive approaches to fill bone defects and favor bone tissue regeneration. Furthermore, by playing on their composition and processing, it is possible to obtain biocompatible systems with adequate chemical, biological, and mechanical properties. However, only a good combination of scaffold and cells, possibly with the aid of incorporated growth factors, can lead to successful results in bone regeneration. This review presents the strategies used to design cellularized hydrogel-based systems for bone regeneration, identifying the key parameters of the many different micro-environments created within hydrogels. PMID:28634532

Gastric carcinoma metastatic to the bone marrow: immunoperoxidase identification of KMO-1 antigen in MGG-destained aspirate.

PubMed

Kobayashi, T K; Yakushiji, M

1991-01-01

A case is presented that illustrates the application of the immunoperoxidase technique to the May-Grünwald-Giemsa (MGG)-destained bone marrow aspirate. The cytologic findings in a MGG-stained smear of the bone marrow suggested a metastatic epithelial tumor. Subsequently, a positive reaction to KMO-1, a monoclonal antibody raised against a colon carcinoma cell line, was demonstrated in tumor cells in the MGG-destained smear sample as well as in the paraffin-embedded section of the primary gastric cancer. The demonstration of the cancer-associated antigen in the MGG-destained material may be useful in establishing the diagnosis of metastatic tumor in the bone marrow.

Bioinspired Collagen Scaffolds in Cranial Bone Regeneration: From Bedside to Bench

PubMed Central

Volpicelli, Elizabeth J.

2018-01-01

Calvarial defects are common reconstructive dilemmas secondary to a variety of etiologies including traumatic brain injury, cerebrovascular disease, oncologic resection, and congenital anomalies. Reconstruction of the calvarium is generally undertaken for the purposes of cerebral protection, contour restoration for psychosocial well-being, and normalization of neurological dysfunction frequently found in patients with massive cranial defects. Current methods for reconstruction using autologous grafts, allogeneic grafts, or allo-plastic materials have significant drawbacks that are unique to each material. The combination of wide medical relevance and the need for a better clinical solution render defects of the cranial skeleton an ideal target for development of regenerative strategies focused on calvarial bone. With the improved understanding of the instructive properties of tissue-specific extracellular matrices and the advent of precise nanoscale modulation in materials science, strategies in regenerative medicine have shifted in paradigm. Previously considered to be simple carriers of stem cells and growth factors, increasing evidence exists for differential materials directing lineage specific differentiation of progenitor cells and tissue regeneration. In this work, we review the clinical challenges for calvarial reconstruction, the anatomy and physiology of bone, and extracellular matrix-inspired, collagen-based materials that have been tested for in vivo cranial defect healing. PMID:28585295

Bone sialoprotein does not interact with pro-gelatinase A (MMP-2) or mediate MMP-2 activation

PubMed Central

2009-01-01

Background A recent model for activation of the zymogen form of matrix metalloproteinase 2 (MMP-2, also known as gelatinase A) has suggested that interactions between the SIBLING protein bone sialoprotein (BSP) and MMP-2 leads to conformational change in MMP-2 that initiates the conversion of the pro-enzyme into a catalytically active form. This model is particularly relevant to cancer cell metastasis to bone since BSP, bound to the αvβ3 integrin through its arginine-glycine-aspartic acid motif, could recruit MMP-2 to the cell surface. Methods We critically assessed the relationship between BSP and proMMP-2 and its activation using various forms of recombinant and purified BSP and MMP-2. Gelatinase and collagenase assays, fluorescence binding assays, real-time PCR, cell culture and pull-down assays were employed to test the model. Results Studies with a fluorogenic substrate for MMP-2 showed no activation of proMMP-2 by BSP. Binding and pull-down assays demonstrated no interaction between MMP-2 and BSP. While BSP-mediated invasiveness has been shown to depend on its integrin-binding RGD sequence, analysis of proMMP-2 activation and the level of membrane type 1 (MT1)-MMP in cells grown on a BSP substratum showed that the BSP-αvβ3 integrin interaction does not induce the expression of MT1-MMP. Conclusion These studies do not support a role for BSP in promoting metastasis through interactions with pro-MMP-2. PMID:19386107

Microgravity

NASA Image and Video Library

2000-12-15

Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Even in normal gravity, bioactive glass particles enhance bone growth in laboratory tests with flat tissue cultures. Ducheyne and his team believe that using the bioactive microcarriers in a rotating bioreactor in microgravity will produce improved, three-dimensional tissue cultures. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and University of Pennsylvania Center for Bioactive Materials and Tissue Engineering.

Finite Element-Based Mechanical Assessment of Bone Quality on the Basis of In Vivo Images.

PubMed

Pahr, Dieter H; Zysset, Philippe K

2016-12-01

Beyond bone mineral density (BMD), bone quality designates the mechanical integrity of bone tissue. In vivo images based on X-ray attenuation, such as CT reconstructions, provide size, shape, and local BMD distribution and may be exploited as input for finite element analysis (FEA) to assess bone fragility. Further key input parameters of FEA are the material properties of bone tissue. This review discusses the main determinants of bone mechanical properties and emphasizes the added value, as well as the important assumptions underlying finite element analysis. Bone tissue is a sophisticated, multiscale composite material that undergoes remodeling but exhibits a rather narrow band of tissue mineralization. Mechanically, bone tissue behaves elastically under physiologic loads and yields by cracking beyond critical strain levels. Through adequate cell-orchestrated modeling, trabecular bone tunes its mechanical properties by volume fraction and fabric. With proper calibration, these mechanical properties may be incorporated in quantitative CT-based finite element analysis that has been validated extensively with ex vivo experiments and has been applied increasingly in clinical trials to assess treatment efficacy against osteoporosis.

Immune Humanization of Immunodeficient Mice Using Diagnostic Bone Marrow Aspirates from Carcinoma Patients

PubMed Central

Werner-Klein, Melanie; Proske, Judith; Werno, Christian; Schneider, Katharina; Hofmann, Hans-Stefan; Rack, Brigitte; Buchholz, Stefan; Ganzer, Roman; Blana, Andreas; Seelbach-Göbel, Birgit; Nitsche, Ulrich

2014-01-01

Tumor xenografts in immunodeficient mice, while routinely used in cancer research, preclude studying interactions of immune and cancer cells or, if humanized by allogeneic immune cells, are of limited use for tumor-immunological questions. Here, we explore a novel way to generate cancer models with an autologous humanized immune system. We demonstrate that hematopoietic stem and progenitor cells (HSPCs) from bone marrow aspirates of non-metastasized carcinoma patients, which are taken at specialized centers for diagnostic purposes, can be used to generate a human immune system in NOD-scid IL2rγ(null) (NSG) and HLA-I expressing NSG mice (NSG-HLA-A2/HHD) comprising both, lymphoid and myeloid cell lineages. Using NSG-HLA-A2/HHD mice, we show that responsive and self-tolerant human T cells develop and human antigen presenting cells can activate human T cells. As critical factors we identified the low potential of bone marrow HSPCs to engraft, generally low HSPC numbers in patient-derived bone marrow samples, cryopreservation and routes of cell administration. We provide here an optimized protocol that uses a minimum number of HSPCs, preselects high-quality bone marrow samples defined by the number of initially isolated leukocytes and intra-femoral or intra-venous injection. In conclusion, the use of diagnostic bone marrow aspirates from non-metastasized carcinoma patients for the immunological humanization of immunodeficient mice is feasible and opens the chance for individualized analyses of anti-tumoral T cell responses. PMID:24830425

A synthetic bioactive resorbable graft for predictable implant reconstruction: part one.

PubMed

Valen, Maurice; Ganz, Scott D

2002-01-01

Animal studies were conducted to evaluate the cell response and chemical potentiality of a synthetic bioactive resorbable graft (SBRG) made of nonceramic cluster particulate of low-temperature HA material. The study evaluated bone-bridging of the SBRG particulates in 1-mm wide implant channels of 5 x 8 mm long roughened titanium interface in 6 dogs and compared results to the same implant channels left empty as controls at 6- and 12-week intervals. Resorption rate capacity and cell response were evaluated with an assessment of the chemical characterization of the synthetic nonceramic material next to the titanium implant interfaces. Results of the animal studies were compared with human histologic biopsies of the SBRG for bone quality, density, and bone growth into defect sites concurrent with resorption time of the graft. One human biopsy consisted of a graft mixture of the SBRG and dense bovine-derived HA, compared under the electron microscope, including histology by H and E staining. Part 1 of this paper presents evidence of the predictability and efficacy of the SBRG osteoconductive, particulate chemical potentiality to aid in the regeneration of lost bone anatomy next to titanium implant interfaces. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional quality and density of bone, including anatomical discrepancies, which can aid in the diagnosis and treatment planning for grafting procedures. When teeth are extracted, the surrounding bone and soft tissue are challenged as a result of the natural resorptive process. The diminished structural foundation for prosthetic reconstruction, with or without implants, can be compromised. A synthetic bioactive resorbable graft material having osteoconductive biochemical and biomechanical qualities similar to the host bone provides the means to improve compromised bone topography for ridge preservation, ridge augmentation, or to enhance the bony site for implant placement and subsequent prosthetic rehabilitation. Part two of this paper will demonstrate clinical applications of the SBRG material for purposes of implant placement and prosthetic reconstruction.

Using interactive multimedia e-Books for learning blood cell morphology in pediatric hematology.

PubMed

Hsiao, Chih-Cheng; Tiao, Mao-Meng; Chen, Chih-Cheng

2016-11-14

This prospective study compares the use of interactive multimedia eBooks (IME) with traditional PowerPoint (TPP) for teaching cell morphology of blood and bone marrow. Fifty-one interns from three Taiwan medical schools training by a single teacher in the pediatric hematology department of Kaohsiung Chang Gung Memorial Hospital, Taiwan, participated in this study. 25 interns were allocated for training with a traditional PowerPoint atlas and 26 interns for training with an interactive multimedia eBook atlas. Learning outcomes were examined by pre-test and post-test using the CellQuiz of CellAtlas App. Attitudes and perceptions were collected by survey questions regarding interest, motivation and effectiveness. There was no difference in the pre-test scores between TPP and IME groups (mean score 27.0 versus 27.9, p = 0.807). However, the interns in the interactive multimedia eBook group achieved significantly better scores in the post-test than the ones in the PowerPoint group (mean score 103.2 versus 70.6; p < 0.001). Overall results of interest, motivation and effectiveness were strongly positive in the multimedia eBook group. Our data supports that interactive multimedia eBooks are more effective than PowerPoint to facilitate learning of cell morphology of blood and bone marrow.

Interaction of tumor and host cells with adhesion and extracellular matrix molecules in the development of multiple myeloma.

PubMed

Teoh, G; Anderson, K C

1997-02-01

Adhesion molecules play an important role in the growth regulation and migration of multiple myeloma (MM) cells. They mediate homing of MM cells to the bone marrow and MM cell to bone marrow stromal cell adhesion, with resultant interleukin-6 related autocrine and paracine growth and antiapoptotic affects. Their pattern of expression on tumor cells correlates with the development of plasma cell leukemia or extramedullary disease. Clinically, expression of adhesion molecules on tumor cells or in the serum has already shown prognostic utility. Finally, since adhesion molecules are involved at multiple steps in the pathogenesis of MM, therapeutic studies may target these molecules.

Interaction between bone marrow stromal cells and neuroblastoma cells leads to a VEGFA-mediated osteoblastogenesis

PubMed Central

HaDuong, Josephine H.; Blavier, Laurence; Baniwal, Sanjeev K.; Frenkel, Baruch; Malvar, Jemily; Punj, Vasu; Sposto, Richard; DeClerck, Yves A.

2017-01-01

The potential role of osteoblasts in bone and bone marrow (BM) metastases in neuroblastoma (NBL) remains unclear. In this study, we examined the effect of NBL cells on the osteoblastic differentiation of bone marrow-derived mesenchymal stromal cells (BMMSC). We show that the presence of NBL cells enhanced the osteoblastic differentiation of BMMSC driven by bone morphogenetic protein (BMP)-4, in the absence of any effect on NBL cell proliferation. Expression profiles of BMMSC driven towards osteoblastic differentiation revealed an increase in vascular endothelial growth factor A (Vegfa) expression in the presence of NBL cells. We demonstrated that NBL cells increased BMMSC-derived VEGFA mRNA and protein and that this was enhanced by BMP-4. However, in similar conditions, neither the addition of an mVEGFA blocking antibody nor exogenous recombinant (r) mVEGFA affected osteoblastic differentiation. In contrast, siRNA-mediated knock-down of VEGFA in BMMSC prevented osteoblastic differentiation in BMP-4-treated co-cultures, an effect that was not reversed in the presence of rmVEGFA. An analysis of murine bones injected with hNBL cells revealed an increase of mVEGFA producing cells near tumor cells concomitantly with an increase in Vegfa and Runx2 mRNA. This coincided with an increase in osteoclasts, in Rankl/Opg mRNA ratio and with the formation of osteolytic lesions. Thus NBL cells promote osteoblastogenesis in the BM by increasing VEGFA expression in BMMSC. Our study provides a new insight into the role of VEGFA in NBL metastases by pointing to the role of stroma-derived intracrine VEGFA in osteoblastogenesis. PMID:25648303

Characterization of neutrophils and macrophages from ex vivo cultured murine bone marrow for morphologic maturation and functional responses by imaging flow cytometry

PubMed Central

Pelletier, Margery G. H.; Szymczak, Klaudia; Barbeau, Anna M.; Prata, Gianna N.; O’Fallon, Kevin S.; Gaines, Peter

2016-01-01

Neutrophils and macrophages differentiate from common myeloid progenitors in the bone marrow, where they undergo nuclear morphologic changes during maturation. During this process, both cell types acquire critical innate immune functions that include phagocytosis of pathogens, and for neutrophils the release of nuclear material called nuclear extracellular traps (NETs). Primary cells used to study these functions are typically purified from mature mouse tissues, but bone marrow-derived ex vivo cultures provide more abundant numbers of progenitors and functionally mature cells. Routine analyses of these cells use conventional microscopy and flow cytometry, which present limitations; microscopy is laborious and subjective, whereas flow cytometry lacks spatial resolution. Here we describe methods to generate enriched populations of neutrophils or macrophages from cryopreserved mouse bone marrow cultured ex vivo, and to use imaging flow cytometry that combines the resolution of microscopy with flow cytometry to analyze cells for morphologic features, phagocytosis, and NETosis. PMID:27663441

Histomorphologic findings on human bone samples six months after bone augmentation of the maxillary sinus with Algipore.

PubMed

Schopper, C; Moser, D; Wanschitz, F; Watzinger, F; Lagogiannis, G; Spassova, E; Ewers, R

1999-01-01

Sinus grafting, a popular and standard treatment for maxillary atrophy, uses a variety of grafting materials. In this study, specimens obtained 6 months after sinus grafting with Algipore were evaluated under light microscopy and showed osseoformation, xenograft degradation, and bone ingrowth into particles. Osteoblastic cells were embedded in the intracorpuscular bone matrix, which indicated that xenograft particles are an osseoconductive scaffold and stimulate matrix deposition. Acute inflammatory responses after insertion of Algipore did not occur. Particles were degraded during physiologic bone remodeling, and newly formed bone gradually replaced resorbed biomaterial.

BONE REGENERATION AFTER DEMINERALIZED BONE MATRIX AND CASTOR OIL (RICINUS COMMUNIS) POLYURETHANE IMPLANTATION

PubMed Central

Leite, Fábio Renato Manzolli; Ramalho, Lizeti Toledo de Oliveira

2008-01-01

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial. PMID:19089203

Biological responses to M13 bacteriophage modified titanium surfaces in vitro.

PubMed

Sun, Yuhua; Li, Yiting; Wu, Baohua; Wang, Jianxin; Lu, Xiong; Qu, Shuxin; Weng, Jie; Feng, Bo

2017-08-01

Phage-based materials have showed great potential in tissue engineering application. However, it is unknown what inflammation response will happen to this kind of materials. This work is to explore the biological responses to M13 bacteriophage (phage) modified titanium surfaces in vitro from the aspects of their interaction with macrophages, osteoblasts and mineralization behavior. Pretreated Ti surface, Ti surfaces with noncrosslinked phage film (APP) and crosslinked phage film (APPG) were compared. Phage films could limit the macrophage adhesion and activity due to inducing adherent-cell apoptosis. The initial inflammatory activity (24h) caused by phage films was relatively high with more production of TNF-α, but in the later stage (7-10days) inflammatory response was reduced with lower TNF-α, IL-6 and higher IL-10. In addition, phage films improved osteoblast adhesion, differentiation, and hydroapatite (HA)-forming via a combination of topographical and biochemcial cues. The noncrosslinked phage film displayed the best immunomodulatory property, osteogenic activity and HA mineralization ability. This work provides better understanding of inflammatory and osteogenetic activity of phage-based materials and contributes to their future application in tissue engineering. In vivo, the bone and immune cells share a common microenvironment, and are being affected by similar cytokines, signaling molecules, transcription factors and membrane receptors. Ideal implants should cause positive biological response, including adequate and appropriate inflammatory reaction, well-balanced bone formation and absorption. Phage-based materials have showed great potential in tissue engineering application. However, at present it is unknown what inflammation response will happen to this kind of materials. A good understanding of the immune response possibly induced by phage-based materials is needed. This work studied the osteoimmunomodulation property of phage films on titanium surface, involving inflammatory response, osteogenic activity and biomineralization ability. It provides more understanding of the phage-based materials and contributes to their future application in tissue engineering. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering.

PubMed

Wang, Zhong-Shan; Feng, Zhi-Hong; Wu, Guo-Feng; Bai, Shi-Zhu; Dong, Yan; Chen, Fa-Ming; Zhao, Yi-Min

2016-06-21

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration.

Development of multi-walled carbon nanotubes reinforced monetite bionanocomposite cements for orthopedic applications.

PubMed

Boroujeni, Nariman Mansoori; Zhou, Huan; Luchini, Timothy J F; Bhaduri, Sarit B

2013-10-01

In this study, we present results of our research on biodegradable monetite (DCPA, CaHPO4) cement with surface-modified multi-walled carbon nanotubes (mMWCNTs) as potential bone defect repair material. The cement pastes showed desirable handling properties and possessed a suitable setting time for use in surgical setting. The incorporation of mMWCNTs shortened the setting time of DCPA and increased the compressive strength of DCPA cement from 11.09±1.85 MPa to 21.56±2.47 MPa. The cytocompatibility of the materials was investigated in vitro using the preosteoblast cell line MC3T3-E1. An increase of cell numbers was observed on both DCPA and DCPA-mMWCNTs. Scanning electron microscopy (SEM) results also revealed an obvious cell growth on the surface of the cements. Based on these results, DCPA-mMWCNTs composite cements can be considered as potential bone defect repair materials. © 2013.

A New In Vitro Model of Breast Cancer Metastasis to Bone

DTIC Science & Technology

2009-04-01

videomicroscopy [11, 12] have revealed that early stage, pre-angiogenic interactions between the cancer cells and the bone environment are crucial regulators of...1995) Steps in tumor metastasis: new concepts from intravital videomicroscopy . Cancer Metastasis Rev 14:279–301. doi:10.1007/BF00690599 12. Chambers AF

A New In Vitro Model of Breast Cancer Metastasis to Bone

DTIC Science & Technology

2008-04-01

intravital videomicroscopy [11, 12] have revealed that early stage, pre-angiogenic interactions between the cancer cells and the bone environment are...Chambers AF, MacDonald IC, Schmidt EE, et al. (1995) Steps in tumor metastasis: New concepts from intravital videomicroscopy . 279 - 301 13. Steeg PS

Anabolic Vitamin D Analogs as Countermeasures to Bone Loss

NASA Technical Reports Server (NTRS)

Li, Wei; Duncan, Randall L.; Karin, Norman J.; Farach-Carson, Mary C.

1997-01-01

We demonstrated for the first time that vitamin D3 influences the effect of PTH on bone cell calcium ion levels. This is a rapid effect, taking place within seconds/minutes. This may prove to be a critical contribution to our understanding of bone physiology in that these two hormones are among the most potent regulators of bone calcium content and of systemic calcium homeostasis. Together with the data gathered from the study of astronauts exposed to microgravity for extended periods, these observations suggest the interaction of vitamin D3 and PTH as a possible therapeutic target in the treatment of bone loss disorders such as osteoporosis and disuse atrophy. Chronic exposure of cultured osteoblasts to vitamin D, altered the number of voltage-sensitive Ca(+2) channels expressed. Estrogen treatment yielded a similar result, suggesting that there is overlap in the mechanism by which these hormones elicit long-term effects on bone cell calcium homeostasis.

Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering.

PubMed

Kolan, Krishna C R; Leu, Ming C; Hilmas, Gregory E; Brown, Roger F; Velez, Mariano

2011-06-01

Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 °C and 695 °C. The sintered scaffolds had pore sizes ranging from 300 to 800 µm with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease.

PubMed

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-07-01

Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease

PubMed Central

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-01-01

Background Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Design and Methods Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Results Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. Conclusions The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone. PMID:21486864

Preparation of flexible bone tissue scaffold utilizing sea urchin test and collagen.

PubMed

Manchinasetty, Naga Vijaya Lakshmi; Oshima, Sho; Kikuchi, Masanori

2017-10-13

Gonads of sea urchin are consumed in Japan and some countries as food and most parts including its tests are discarded as marine wastes. Therefore, utilization of them as functional materials would reduce the waste as well as encourage Japanese fishery. In this study, magnesium containing calcite granules collected from sea urchin tests were hydrothermally phosphatized and the obtained granules were identified as approximately 82% in mass of magnesium containing β-tricalcium phosphate and 18% in mass of nonstoichiometric hydroxyapatite, i.e., a biphasic calcium phosphate, maintaining the original porous network. Shape-controlled scaffolds were fabricated with the obtained biphasic calcium phosphate granules and collagen. The scaffolds showed good open porosity (83.84%) and adequate mechanical properties for handling during cell culture and subsequent operations. The MG-63 cells showed higher proliferation and osteogenic differentiation in comparison to a control material, the collagen sponge with the same size. Furthermore, cell viability assay proved that the scaffolds were not cytotoxic. These results suggest that scaffold prepared using sea urchin test derived calcium phosphate and collagen could be a potential candidate of bone void fillers for non-load bearing defects in bone reconstruction as well as scaffolds for bone tissue engineering.

Coatings of titanium substrates with xCaO · (1 - x)SiO2 sol-gel materials: characterization, bioactivity and biocompatibility evaluation.

PubMed

Catauro, M; Papale, F; Bollino, F

2016-01-01

The objective of this study has been to develop low temperature sol-gel coatings to modify the surface of commercially pure titanium grade 4 (a material generally used in dental application) and to evaluate their bioactivity and biocompatibility on the substrate. Glasses of composition expressed by the following general formula xCaO · (1 - x)SiO2 (0.0

Characterization of synthetic foam structures used to manufacture artificial vertebral trabecular bone.

PubMed

Fürst, David; Senck, Sascha; Hollensteiner, Marianne; Esterer, Benjamin; Augat, Peter; Eckstein, Felix; Schrempf, Andreas

2017-07-01

Artificial materials reflecting the mechanical properties of human bone are essential for valid and reliable implant testing and design. They also are of great benefit for realistic simulation of surgical procedures. The objective of this study was therefore to characterize two groups of self-developed synthetic foam structures by static compressive testing and by microcomputed tomography. Two mineral fillers and varying amounts of a blowing agent were used to create different expansion behavior of the synthetic open-cell foams. The resulting compressive and morphometric properties thus differed within and also slightly between both groups. Apart from the structural anisotropy, the compressive and morphometric properties of the synthetic foam materials were shown to mirror the respective characteristics of human vertebral trabecular bone in good approximation. In conclusion, the artificial materials created can be used to manufacture valid synthetic bones for surgical training. Further, they provide novel possibilities for studying the relationship between trabecular bone microstructure and biomechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent advances in bone tissue engineering scaffolds

PubMed Central

Bose, Susmita; Roy, Mangal; Bandyopadhyay, Amit

2012-01-01

Bone disorders are of significant concern due to increase in the median age of our population. Traditionally, bone grafts have been used to restore damaged bone. Synthetic biomaterials are now being used as bone graft substitutes. These biomaterials were initially selected for structural restoration based on their biomechanical properties. Later scaffolds were engineered to be bioactive or bioresorbable to enhance tissue growth. Now scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous, biodegradable materials that harbor different growth factors, drugs, genes or stem cells. In this review, we highlight recent advances in bone scaffolds and discuss aspects that still need to be improved. PMID:22939815

Scanning electron microscopy of bone.

PubMed

Boyde, Alan

2012-01-01

This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

Osteogenesis and cytotoxicity of a new Carbon Fiber/Flax/Epoxy composite material for bone fracture plate applications.

PubMed

Bagheri, Zahra S; Giles, Erica; El Sawi, Ihab; Amleh, Asma; Schemitsch, Emil H; Zdero, Radovan; Bougherara, Habiba

2015-01-01

This study is part of an ongoing program to develop a new CF/Flax/Epoxy bone fracture plate to be used in orthopedic trauma applications. The purpose was to determine this new plate's in-vitro effects on the level of bone formation genes, as well as cell viability in comparison with a medical grade metal (i.e. stainless steel) commonly employed for fabrication of bone plates (positive control). Cytotoxicity and osteogenesis induced by wear debris of the material were assessed using Methyl Tetrazolium (MTT) assay and reverse transcription polymerase chain reaction (RT-PCR) for 3 osteogenesis specific gene markers, including bone morphogenetic proteins (BMP2), runt-related transcription factor 2 (Runx2) and Osterix. Moreover, the Flax/Epoxy and CF/Epoxy composites were examined separately for their wettability properties by water absorption and contact angle (CA) tests using the sessile drop technique. The MTT results for indirect and direct assays indicated that the CF/Flax/Epoxy composite material showed comparable cell viability with no cytotoxicity at all incubation times to that of the metal group (p≥0.05). Osteogenesis test results showed that the expression level of Runx2 marker induced by CF/Flax/Epoxy were significantly higher than those induced by metal after 48 h (p=0.57). Also, the Flax/Epoxy composite revealed a hydrophilic character (CA=68.07°±2.05°) and absorbed more water up to 17.2% compared to CF/Epoxy, which reached 1.25% due to its hydrophobic character (CA=93.22°±1.95°) (p<0.001). Therefore, the new CF/Flax/Epoxy may be a potential candidate for medical applications as a bone fracture plate, as it showed similar cell viability with no negative effect on gene expression levels responsible for bone formation compared to medical grade stainless steel. Copyright © 2014 Elsevier B.V. All rights reserved.

The effects on bone cells of metal ions released from orthopaedic implants. A review

PubMed Central

Sansone, Valerio; Pagani, Davide; Melato, Marco

2013-01-01

Summary The increasing use of orthopedic implants and, in particular, of hip and knee joint replacements for young and active patients, has stimulated interest and concern regarding the chronic, long-term effects of the materials used. This review focuses on the current knowledge of the adverse biologic reactions to metal particles released from orthopaedic implants in vivo and in vitro. More specifically, the purpose of this article is to provide an overview of the current literature about the adverse effects of metal particles on bone cells and peri-implant bone. PMID:23858309

Three-Dimensional Mechanical Loading Modulates the Osteogenic Response of Mesenchymal Stem Cells to Tumor-Derived Soluble Signals

PubMed Central

Lynch, Maureen E.; Chiou, Aaron E.; Lee, Min Joon; Marcott, Stephen C.; Polamraju, Praveen V.; Lee, Yeonkyung

2016-01-01

Dynamic mechanical loading is a strong anabolic signal in the skeleton, increasing osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) and increasing the bone-forming activity of osteoblasts, but its role in bone metastatic cancer is relatively unknown. In this study, we integrated a hydroxyapatite-containing three-dimensional (3D) scaffold platform with controlled mechanical stimulation to investigate the effects of cyclic compression on the interplay between breast cancer cells and BM-MSCs as it pertains to bone metastasis. BM-MSCs cultured within mineral-containing 3D poly(lactide-co-glycolide) (PLG) scaffolds differentiated into mature osteoblasts, and exposure to tumor-derived soluble factors promoted this process. When BM-MSCs undergoing osteogenic differentiation were exposed to conditioned media collected from mechanically loaded breast cancer cells, their gene expression of osteopontin was increased. This was further enhanced when mechanical compression was simultaneously applied to BM-MSCs, leading to more uniformly deposited osteopontin within scaffold pores. These results suggest that mechanical loading of 3D scaffold-based culture models may be utilized to evaluate the role of physiologically relevant physical cues on bone metastatic breast cancer. Furthermore, our data imply that cyclic mechanical stimuli within the bone microenvironment modulate interactions between tumor cells and BM-MSCs that are relevant to bone metastasis. PMID:27401765

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

PubMed

Ramirez-GarciaLuna, Jose Luis; Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H; Li, Ailian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Henderson, Janet E; Martineau, Paul A

2017-01-01

In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice

PubMed Central

Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H.; Li, Ailian; Feyerabend, Thorsten B.; Rodewald, Hans-Reimer; Henderson, Janet E.; Martineau, Paul A.

2017-01-01

In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair. PMID:28350850

CHIP regulates bone mass by targeting multiple TRAF family members in bone marrow stromal cells.

PubMed

Wang, Tingyu; Li, Shan; Yi, Dan; Zhou, Guang-Qian; Chang, Zhijie; Ma, Peter X; Xiao, Guozhi; Chen, Di

2018-01-01

Carboxyl terminus of Hsp70-interacting protein (CHIP or STUB1) is an E3 ligase and regulates the stability of several proteins which are involved in different cellular functions. Our previous studies demonstrated that Chip deficient mice display bone loss phenotype due to increased osteoclast formation through enhancing TRAF6 activity in osteoclasts. In this study we provide novel evidence about the function of CHIP. We found that osteoblast differentiation and bone formation were also decreased in Chip KO mice. In bone marrow stromal (BMS) cells derived from Chip -/- mice, expression of a panel of osteoblast marker genes was significantly decreased. ALP activity and mineralized bone matrix formation were also reduced in Chip- deficient BMS cells. We also found that in addition to the regulation of TRAF6, CHIP also inhibits TNFα-induced NF-κB signaling through promoting TRAF2 and TRAF5 degradation. Specific deletion of Chip in BMS cells downregulated expression of osteoblast marker genes which could be reversed by the addition of NF-κB inhibitor. These results demonstrate that the osteopenic phenotype observed in Chip -/- mice was due to the combination of increased osteoclast formation and decreased osteoblast differentiation. Taken together, our findings indicate a significant role of CHIP in bone remodeling.

Evaluation of cell sheet application on one wall bone defect in Macaca nemestrina through periostin expression

NASA Astrophysics Data System (ADS)

Tamin, R. Y.; Soeroso, Y.; Amir, L.; Idrus, E.

2017-08-01

Chronic periodontitis is an oral disease in which the destruction of periodontal tissue leads to tooth loss. Regenerative therapy for attachment cannot be applied to one wall bone defects owing to the minimal existing healthy bone. Tissue engineering in the form of cell sheets has been developed to overcome this limitation. In a previous study, cell sheet application to a one wall bone defect in Macaca nemestrina showed good clinical results. To evaluate the effectiveness of cell sheet application histologically, the level of periostin expression in the gingival crevicular fluid (GCF) of M. nemestrina was determined. Periostin is a 90-kDa protein that regulates coordination and interaction for regeneration and tissue repair. A laboratory observation study was performed to see the differences in periostin levels in samples collected from M. nemestrina’s GCF, where a cell sheet was applied to the bone defect. Gel electrophoresis with SDS-PAGE was performed to detect periostin expression based on its molecular weight and to compare the expression band between the cell sheet and the control at 1, 2, and 3 weeks after treatment. The gel electrophoresis result shows different thicknesses of the protein band around the molecular weight of periostin between the cell sheet groups.

Complexity in modeling of residual stresses and strains during polymerization of bone cement: effects of conversion, constraint, heat transfer, and viscoelastic property changes.

PubMed

Gilbert, Jeremy L

2006-12-15

Aseptic loosening of cemented joint prostheses remains a significant concern in orthopedic biomaterials. One possible contributor to cement loosening is the development of porosity, residual stresses, and local fracture of the cement that may arise from the in-situ polymerization of the cement. In-situ polymerization of acrylic bone cement is a complex set of interacting processes that involve polymerization reactions, heat generation and transfer, full or partial mechanical constraint, evolution of conversion- and temperature-dependent viscoelastic material properties, and thermal and conversion-driven changes in the density of the cement. Interactions between heat transfer and polymerization can lead to polymerization fronts moving through the material. Density changes during polymerization can, in the presence of mechanical constraint, lead to the development of locally high residual strain energy and residual stresses. This study models the interactions during bone cement polymerization and determines how residual stresses develop in cement and incorporates temperature and conversion-dependent viscoelastic behavior. The results show that the presence of polymerization fronts in bone cement result in locally high residual strain energies. A novel heredity integral approach is presented to track residual stresses incorporating conversion and temperature dependent material property changes. Finally, the relative contribution of thermal- and conversion-dependent strains to residual stresses is evaluated and it is found that the conversion-based strains are the major contributor to the overall behavior. This framework provides the basis for understanding the complex development of residual stresses and can be used as the basis for developing more complex models of cement behavior.

Carbon nanotubes functionalized with fibroblast growth factor accelerate proliferation of bone marrow-derived stromal cells and bone formation

NASA Astrophysics Data System (ADS)

Hirata, Eri; Ménard-Moyon, Cécilia; Venturelli, Enrica; Takita, Hiroko; Watari, Fumio; Bianco, Alberto; Yokoyama, Atsuro

2013-11-01

Multi-walled carbon nanotubes (MWCNTs) were functionalized with fibroblast growth factor (FGF) and the advantages of their use as scaffolds for bone augmentation were evaluated in vitro and in vivo. The activity of FGF was assessed by measuring the effect on the proliferation of rat bone marrow stromal cells (RBMSCs). The presence of FGF enhanced the proliferation of RBMSCs and the FGF covalently conjugated to the nanotubes (FGF-CNT) showed the same effect as FGF alone. In addition, FGF-CNT coated sponges were implanted between the parietal bone and the periosteum of rats and the formation of new bone was investigated. At day 14 after implantation, a larger amount of newly formed bone was clearly observed in most pores of FGF-CNT coated sponges. These findings indicated that MWCNTs accelerated new bone formation in response to FGF, as well as the integration of particles into new bone during its formation. Scaffolds coated with FGF-CNT could be considered as promising novel substituting materials for bone regeneration in future tissue engineering applications.

Multiscale fluid-structure interaction modelling to determine the mechanical stimulation of bone cells in a tissue engineered scaffold.

PubMed

Zhao, Feihu; Vaughan, Ted J; Mcnamara, Laoise M

2015-04-01

Recent studies have shown that mechanical stimulation, by means of flow perfusion and mechanical compression (or stretching), enhances osteogenic differentiation of mesenchymal stem cells and bone cells within biomaterial scaffolds in vitro. However, the precise mechanisms by which such stimulation enhances bone regeneration is not yet fully understood. Previous computational studies have sought to characterise the mechanical stimulation on cells within biomaterial scaffolds using either computational fluid dynamics or finite element (FE) approaches. However, the physical environment within a scaffold under perfusion is extremely complex and requires a multiscale and multiphysics approach to study the mechanical stimulation of cells. In this study, we seek to determine the mechanical stimulation of osteoblasts seeded in a biomaterial scaffold under flow perfusion and mechanical compression using multiscale modelling by two-way fluid-structure interaction and FE approaches. The mechanical stimulation, in terms of wall shear stress (WSS) and strain in osteoblasts, is quantified at different locations within the scaffold for cells of different attachment morphologies (attached, bridged). The results show that 75.4 % of scaffold surface has a WSS of 0.1-10 mPa, which indicates the likelihood of bone cell differentiation at these locations. For attached and bridged osteoblasts, the maximum strains are 397 and 177,200 με, respectively. Additionally, the results from mechanical compression show that attached cells are more stimulated (maximum strain = 22,600 με) than bridged cells (maximum strain = 10.000 με)Such information is important for understanding the biological response of osteoblasts under in vitro stimulation. Finally, a combination of perfusion and compression of a tissue engineering scaffold is suggested for osteogenic differentiation.

Bioactive Molecule-loaded Drug Delivery Systems to Optimize Bone Tissue Repair.

PubMed

Oshiro, Joao Augusto; Sato, Mariana Rillo; Scardueli, Cassio Rocha; Lopes de Oliveira, Guilherme Jose Pimentel; Abucafy, Marina Paiva; Chorilli, Marlus

2017-01-01

Bioactive molecules such as peptides and proteins can optimize the repair of bone tissue; however, the results are often unpredictable when administered alone, owing to their short biological half-life and instability. Thus, the development of bioactive molecule-loaded drug delivery systems (DDS) to repair bone tissue has been the subject of intense research. DDS can optimize the repair of bone tissue owing to their physicochemical properties, which improve cellular interactions and enable the incorporation and prolonged release of bioactive molecules. These characteristics are fundamental to favor bone tissue homeostasis, since the biological activity of these factors depends on how accessible they are to the cell. Considering the importance of these DDS, this review aims to present relevant information on DDS when loaded with osteogenic growth peptide and bone morphogenetic protein. These are bioactive molecules that are capable of modulating the differentiation and proliferation of mesenchymal cells in bone tissue cells. Moreover, we will present different approaches using these peptide and protein-loaded DDS, such as synthetic membranes and scaffolds for bone regeneration, synthetic grafts, bone cements, liposomes, and micelles, which aim at improving the therapeutic effectiveness, and we will compare their advantages with commercial systems. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effects of polycaprolactone-tricalcium phosphate, recombinant human bone morphogenetic protein-2 and dog mesenchymal stem cells on bone formation: pilot study in dogs.

PubMed

Kim, Sun-Jong; Kim, Myung-Rae; Oh, Jin-Sub; Han, Inho; Shin, Sang-Wan

2009-12-31

The aim of this study was to evaluate the survival, proliferation, and bone formation of dog mesenchymal stem cells (dMSCs) in the graft material by using Polycaprolactone-tricalcium phosphate (PCL-TCP), auto-fibrin glue (AFG), recombinant human bone morphogenetic protein-2 (rhBMP-2), and dMSCs after a transplantation to the scapula of adult beagle dogs. The subjects were two beagle dogs. Total dose of rhBMP-2 on each block was 10 microg with 50 microg/mg concentration. The cortical bone of the scapula of the dog was removed which was the same size of PCL-TCP block (Osteopore International Pte, Singapore; 5.0x5.0x8.0 mm in size), and the following graft material then was fixed with orthodontic mini-implant, Dual-top (Titanium alloy, Jeil Co. Seoul, Korea). Four experimental groups were prepared for this study, Group 1: PCL-TCP + aFG; Group 2: PCL-TCP + aFG + dMSCs; Group 3: PCL-TCP + aFG + dMSCs + rhBMP-2; Group 4: PCL-TCP + aFG + dMSCs + rhBMP-2 + PCL membrane. The survival or proliferation of dMSCs cells was identified with an extracted tissue through a fluorescence microscope, H-E staining and Von-Kossa staining in two weeks and four weeks after the transplantation. The survival and proliferation of dMSCs were identified through a fluorescence microscope from both Group 1 and Group 2 in two weeks and four weeks after the transplantation. Histological observation also found that the injected cells were proliferating well in the G2, G3, and G4 scaffolds. This study concluded that bone ingrowth occurred in PCL-TCP scaffold which was transplanted with rhBMP-2, and MSCs did not affect bone growth. More sufficient healing time would be needed to recognize effects of dMSCs on bone formation.

N-acetyl cysteine (NAC)-mediated detoxification and functionalization of poly(methyl methacrylate) bone cement.

PubMed

Tsukimura, Naoki; Yamada, Masahiro; Aita, Hideki; Hori, Norio; Yoshino, Fumihiko; Chang-Il Lee, Masaichi; Kimoto, Katsuhiko; Jewett, Anahid; Ogawa, Takahiro

2009-07-01

Currently used poly(methyl methacrylate) (PMMA)-based bone cement lacks osteoconductivity and induces osteolysis and implant loosening due to its cellular and tissue-toxicity. A high percentage of revision surgery following the use of bone cement has become a significant universal problem. This study determined whether incorporation of the amino acid derivative N-acetyl cysteine (NAC) in bone cement reduces its cytotoxicity and adds osteoconductivity to the material. Biocompatibility and bioactivity of PMMA-based bone cement with or without 25mm NAC incorporation was examined using rat bone marrow-derived osteoblastic cells. Osteoconductive potential of NAC-incorporated bone cement was determined by microCT bone morphometry and implant biomechanical test in the rat model. Generation of free radicals within the polymerizing bone cement was examined using electron spin resonance spectroscopy. Severely compromised viability and completely suppressed phenotypes of osteoblasts on untreated bone cement were restored to the normal level by NAC incorporation. Bone volume formed around 25mm NAC-incorporated bone cement was threefold greater than that around control bone cement. The strength of bone-bone cement integration was 2.2 times greater for NAC-incorporated bone cement. For NAC-incorporated bone cement, the spike of free radical generation ended within 12h, whereas for control bone cement, a peak level lasted for 6 days and a level greater than half the level of the peak was sustained for 20 days. NAC also increased the level of antioxidant glutathione in osteoblasts. These results suggest that incorporation of NAC in PMMA bone cement detoxifies the material by immediate and effective in situ scavenging of free radicals and increasing intracellular antioxidant reserves, and consequently adds osteoconductivity to the material.

Microsphere-based scaffolds encapsulating chondroitin sulfate or decellularized cartilage

PubMed Central

Gupta, Vineet; Tenny, Kevin M; Barragan, Marilyn; Berkland, Cory J; Detamore, Michael S

2016-01-01

Extracellular matrix materials such as decellularized cartilage (DCC) and chondroitin sulfate (CS) may be attractive chondrogenic materials for cartilage regeneration. The goal of the current study was to investigate the effects of encapsulation of DCC and CS in homogeneous microsphere-based scaffolds, and to test the hypothesis that encapsulation of these extracellular matrix materials would induce chondrogenesis of rat bone marrow stromal cells. Four different types of homogeneous scaffolds were fabricated from microspheres of poly(D,L-lactic-co-glycolic acid): Blank (poly(D,L-lactic-co-glycolic acid) only; negative control), transforming growth factor-β3 encapsulated (positive control), DCC encapsulated, and CS encapsulated. These scaffolds were then seeded with rat bone marrow stromal cells and cultured for 6 weeks. The DCC and CS encapsulation altered the morphological features of the microspheres, resulting in higher porosities in these groups. Moreover, the mechanical properties of the scaffolds were impacted due to differences in the degree of sintering, with the CS group exhibiting the highest compressive modulus. Biochemical evidence suggested a mitogenic effect of DCC and CS encapsulation on rat bone marrow stromal cells with the matrix synthesis boosted primarily by the inherently present extracellular matrix components. An important finding was that the cell seeded CS and DCC groups at week 6 had up to an order of magnitude higher glycosaminoglycan contents than their acellular counterparts. Gene expression results indicated a suppressive effect of DCC and CS encapsulation on rat bone marrow stromal cell chondrogenesis with differences in gene expression patterns existing between the DCC and CS groups. Overall, DCC and CS were easily included in microsphere-based scaffolds; however, there is a requirement to further refine their concentrations to achieve the differentiation profiles we seek in vitro. PMID:27358376

Variation of mechanical property of single-walled carbon nanotubes-treated cells explored by atomic force microscopy.

PubMed

Dulińska-Molak, Ida; Mao, Hongli; Kawazoe, Naoki; Chen, Guoping

2014-04-01

With a range of biological properties, single-walled carbon nanotubes (SWCNTs) are a promising material for nanobiotechnology. Concerns about their potential effect on human health have led to the interest in understanding the interaction between SWCNTs and cells. There are many reports showing the potential cellular effects of SWCNTs but this issue is quite controversially discussed in the literature. In this study, we used conventional biological evaluation methods and atomic force microscopy (AFM) to compare the effects of SWCNTs on three different cell types: bovine articular chondrocytes, human bone marrow-derived mesenchymal stem cells and HeLa cells. No obvious effects of SWCNTs on cell morphology and viability were observed during 3 days in vitro culture. However, SWCNTs significantly increased the Young's modulus of all the three types of cells. The effect of SWCNTs on Young's modulus was in an increasing order of Hela cells < chondrocytes < mesenchymal stem cells. AFM was shown to be a useful tool for investigation of the effect of nanomaterials on mechanical property of cells.

Biocompatibility and anti-microbiological activity characterization of novel coatings for dental implants: A primer for non-biologists

NASA Astrophysics Data System (ADS)

Monsees, Thomas

2016-08-01

With regard to biocompatibility, the cardinal requirement for dental implants and other medical devices that are in long-term contact with tissue is that the material does not cause any adverse effect to the patient. To warrant stability and function of the implant, proper osseointegration is a further prerequisite. Cells interact with the implant surface as the interface between bulk material and biological tissue. Whereas structuring, deposition of a thin film or other modifications of the surface are crucial parameters in determining favorable adhesion of cells, corrosion of metal surfaces and release of ions can affect cell viability. Both parameters are usually tested using in vitro cytotoxicity and adhesion assays with bone or fibroblasts cells. For bioactive surface modifications, further tests should be considered for biocompatibility evaluation. Depending on the type of modification, this may include analysis of specific cell functions or the determination of antimicrobial activities. The latter is of special importance as bacteria and yeast present in the oral cavity can be introduced during the implantation process and this may lead to chronic infections and implant failure. An antimicrobial coating of the implant is a way to avoid that. This review describes the essential biocompatibility assays for evaluation of new implant materials required by ISO 10993 and also gives an overview on recent test methods for specific coatings of dental implants.

Do Clinical and Radiological Assessments Contribute to the Understanding of Biomaterials? Results From a Prospective Randomized Sinus Augmentation Split-Mouth Trial.

PubMed

Lorenz, Jonas; Korzinskas, Tadas; Chia, Poju; Maawi, Sarah Al; Eichler, Katrin; Sader, Robert A; Ghanaati, Shahram

2018-02-01

The present prospective randomized split-mouth trial reports on the 3-year clinical and radiological follow-up investigation of implants placed 7 months after sinus augmentation with 2 different bone substitute materials. The aim of the study was to complete the histologic observation of cellular reactions by analyses of the implants and the volumetric changes of the augmented bone substitute materials. A sinus augmentation split-mouth trial was performed in 14 patients with the synthetic bone substitute material Nanobone (NB) and the xenogeneic Bio-Oss (BO). Changes in volume and density of the augmented biomaterials were investigated by analysis of computed tomography scans, taken immediately after augmentation and after 7 months. Clinical implant parameters were assessed after 3 years of loading. Both bone substitute materials underwent nonsignificant volume reduction and significant increase in bone density over an integration period of 7 months. No significant differences concerning volume and bone density were observed between the groups. Three years after loading, 51 of 53 implants were in situ with no peri-implant infections, and only a few soft-tissue variations were present. The present prospective randomized study showed that no differences could be observed clinically and radiologically. Accordingly, it seems that both biomaterials, independent of their physicochemical composition, enable clinical success and long-time stability for dental implants. Interestingly, the histological results showed distinct differences in cellular reactions: While the xenogeneic BO induced a mild tissue reaction with only few multinucleated giant cells and comparably low vascularization, the synthetic NB induced a multinucleated giant cell-triggered tissue reaction with an increase of vascularization. Thus, the present study showed that a combination analysis-histological, clinical, and radiological-is necessary for a detailed assessment of a biomaterial's quality for clinical application.

Incorporation of osteogenic and angiogenic small interfering RNAs into chitosan sponge for bone tissue engineering

PubMed Central

Jia, Sen; Yang, Xinjie; Song, Wen; Wang, Lei; Fang, Kaixiu; Hu, Zhiqiang; Yang, Zihui; Shan, Chun; Lei, Delin; Lu, Bin

2014-01-01

Engineered bone substitutes are being extensively explored in response to growing demand. However, the angiogenesis that occurs during bone formation is often overlooked in scaffold design. In this novel study, we incorporated two small interfering RNAs (siRNAs), ie, small interfering RNA targets casein kinase 2 interaction protein 1 (siCkip-1) and small interfering RNA targets soluble VEGF receptor 1 (siFlt-1), which can promote osteogenesis and angiogenesis, into a chitosan sponge. This scaffold could maintain siRNAs for over 2 weeks in neutral phosphate-buffered saline and degraded rapidly in the presence of lysozyme. The chitosan sponge with siCkip-1 and siFlt-1 in vitro bioactivity was investigated using mesenchymal stem cells. Target genes were significantly suppressed, and osteocalcin, alkaline phosphatase, and vascular endothelial growth factor were significantly upregulated. Alizarin Red staining revealed that mineralization of the extracellular matrix was markedly enhanced by dual transfection. Further analysis by immunofluorescence confirmed that the siRNA-modified scaffold simultaneously improved the expression of osteocalcin and von Willebrand factor. In vivo testing in a skull critical-size defect model showed marked bone regeneration in rats treated with siCkip-1 and siFlt-1. In conclusion, chitosan sponge containing osteogenic and angiogenic siRNAs may be used as a scaffold for bone regeneration. The dual siRNA concept may also be useful in the biofunctionalization of other materials. PMID:25429217

Reprogramming hMSCs morphology with silicon/porous silicon geometric micro-patterns.

PubMed

Ynsa, M D; Dang, Z Y; Manso-Silvan, M; Song, J; Azimi, S; Wu, J F; Liang, H D; Torres-Costa, V; Punzon-Quijorna, E; Breese, M B H; Garcia-Ruiz, J P

2014-04-01

Geometric micro-patterned surfaces of silicon combined with porous silicon (Si/PSi) have been manufactured to study the behaviour of human Mesenchymal Stem Cells (hMSCs). These micro-patterns consist of regular silicon hexagons surrounded by spaced columns of silicon equilateral triangles separated by PSi. The results show that, at an early culture stage, the hMSCs resemble quiescent cells on the central hexagons with centered nuclei and actin/β-catenin and a microtubules network denoting cell adhesion. After 2 days, hMSCs adapted their morphology and cytoskeleton proteins from cell-cell dominant interactions at the center of the hexagonal surface. This was followed by an intermediate zone with some external actin fibres/β-catenin interactions and an outer zone where the dominant interactions are cell-silicon. Cells move into silicon columns to divide, migrate and communicate. Furthermore, results show that Runx2 and vitamin D receptors, both specific transcription factors for skeleton-derived cells, are expressed in cells grown on micropatterned silicon under all observed circumstances. On the other hand, non-phenotypic alterations are under cell growth and migration on Si/PSi substrates. The former consideration strongly supports the use of micro-patterned silicon surfaces to address pending questions about the mechanisms of human bone biogenesis/pathogenesis and the study of bone scaffolds.

Top down and bottom up engineering of bone.

PubMed

Knothe Tate, Melissa L

2011-01-11

The goal of this retrospective article is to place the body of my lab's multiscale mechanobiology work in context of top-down and bottom-up engineering of bone. We have used biosystems engineering, computational modeling and novel experimental approaches to understand bone physiology, in health and disease, and across time (in utero, postnatal growth, maturity, aging and death, as well as evolution) and length scales (a single bone like a femur, m; a sample of bone tissue, mm-cm; a cell and its local environment, μm; down to the length scale of the cell's own skeleton, the cytoskeleton, nm). First we introduce the concept of flow in bone and the three calibers of porosity through which fluid flows. Then we describe, in the context of organ-tissue, tissue-cell and cell-molecule length scales, both multiscale computational models and experimental methods to predict flow in bone and to understand the flow of fluid as a means to deliver chemical and mechanical cues in bone. Addressing a number of studies in the context of multiple length and time scales, the importance of appropriate boundary conditions, site specific material parameters, permeability measures and even micro-nanoanatomically correct geometries are discussed in context of model predictions and their value for understanding multiscale mechanobiology of bone. Insights from these multiscale computational modeling and experimental methods are providing us with a means to predict, engineer and manufacture bone tissue in the laboratory and in the human body. Copyright © 2010 Elsevier Ltd. All rights reserved.

Perspectives on the role of nanotechnology in bone tissue engineering.

PubMed

Saiz, Eduardo; Zimmermann, Elizabeth A; Lee, Janice S; Wegst, Ulrike G K; Tomsia, Antoni P

2013-01-01

This review surveys new developments in bone tissue engineering, specifically focusing on the promising role of nanotechnology and describes future avenues of research. The review first reinforces the need to fabricate scaffolds with multi-dimensional hierarchies for improved mechanical integrity. Next, new advances to promote bioactivity by manipulating the nanolevel internal surfaces of scaffolds are examined followed by an evaluation of techniques using scaffolds as a vehicle for local drug delivery to promote bone regeneration/integration and methods of seeding cells into the scaffold. Through a review of the state of the field, critical questions are posed to guide future research toward producing materials and therapies to bring state-of-the-art technology to clinical settings. The development of scaffolds for bone regeneration requires a material able to promote rapid bone formation while possessing sufficient strength to prevent fracture under physiological loads. Success in simultaneously achieving mechanical integrity and sufficient bioactivity with a single material has been limited. However, the use of new tools to manipulate and characterize matter down to the nano-scale may enable a new generation of bone scaffolds that will surpass the performance of autologous bone implants. Published by Elsevier Ltd.

On the relationship between the dynamic behavior and nanoscale staggered structure of the bone

NASA Astrophysics Data System (ADS)

Qwamizadeh, Mahan; Zhang, Zuoqi; Zhou, Kun; Zhang, Yong Wei

2015-05-01

Bone, a typical load-bearing biological material, composed of ordinary base materials such as organic protein and inorganic mineral arranged in a hierarchical architecture, exhibits extraordinary mechanical properties. Up to now, most of previous studies focused on its mechanical properties under static loading. However, failure of the bone occurs often under dynamic loading. An interesting question is: Are the structural sizes and layouts of the bone related or even adapted to the functionalities demanded by its dynamic performance? In the present work, systematic finite element analysis was performed on the dynamic response of nanoscale bone structures under dynamic loading. It was found that for a fixed mineral volume fraction and unit cell area, there exists a nanoscale staggered structure at some specific feature size and layout which exhibits the fastest attenuation of stress waves. Remarkably, these specific feature sizes and layouts are in excellent agreement with those experimentally observed in the bone at the same scale, indicating that the structural size and layout of the bone at the nanoscale are evolutionarily adapted to its dynamic behavior. The present work points out the importance of dynamic effect on the biological evolution of load-bearing biological materials.