Bone Regeneration Research Research Articles

A Macroscopic Exploration of the Ideoscape on Exosomes for Bone Regeneration

Background: Exosomes, nanoscale extracellular vesicles, play a crucial role in tissue physiology and regeneration. This study uses infometric techniques to explore the structure of exosome-based tissue and bone regeneration research. Methods: We applied BERTopic, an advanced topic modeling algorithm, to a comprehensive corpus of the scientific literature on exosomes and tissue regeneration, identifying key themes such as stem cell studies, tissue healing, and regenerative applications, with orthopedics and dentistry emerging as dominant subfields. To further investigate the ‘ideoscape’, i.e., the conceptual landscape that maps how ideas, methods, and themes are interconnected across the field, we extracted significant concepts from abstracts using GPT 3.5 turbo and created knowledge graphs. Results: Our analysis revealed rapid growth in the field of dental stem cell regeneration, which has outpaced other bone regeneration topics by twofold. This analysis highlighted central themes such as periodontal stem cells and their cellular processes—proliferation, migration, and differentiation—along with their clinical applications. Our approach provided a clear visualization of the field’s intellectual structure, showing how emerging topics are interconnected. Our findings offer a comprehensive view of the evolving trends in exosome-based bone regeneration, revealing not only the most active research areas but also gaps and opportunities for further investigation. Conclusions: This study exemplifies the utility of combining topic modeling with knowledge graph creation to map research trends, offering a flexible and largely automated tool for researchers to explore the vast bodies of literature and guide future research directions.

Optical coherence tomography angiography allows longitudinal monitoring of angiogenesis in the critical-sized defect model

Purpose: This study aims to evaluate the capability of optical coherence tomography angiography (OCTA) for imaging the microvasculature within a critical bone defect, to longitudinally observe vascular alterations, and quantify the microvascular density and morphology in a model of a critical-sized defect.Methods: An OCTA system was used to longitudinally monitor angiogenesis in four rat models presenting critical-sized defects with observations recorded on days 7, 14, and 28 post-defect creation. Simultaneously, angiogenesis in three additional rat models was evaluated through a conventional histological analysis involving hematoxylin and eosin staining.Results: OCTA was successful in acquiring in vivo 3D vascular perfusion mapping within the critical-sized defect, and it allowed for quantitative analysis of the microvasculature’s density and morphology. The OCTA imagery of the blood microvasculature revealed a noticeable augmentation in the number and size of vessels, with more extensive vessel convergence observed on day 14 compared to both days 7 and 28. Complementing these observations, quantitative analysis demonstrated that the vessel area density (VAD) and maximum vascular diameter index (MVDI) were significantly larger on day 14 in comparison to measurements taken on days 7 and 28.Conclusion: Leveraging its ability to capture high-resolution images, OCTA facilitated longitudinal monitoring of angiogenesis in models of critical-sized defects. Therefore, it potentially serves as a non-invasive experimental tool beneficial for bone regeneration research.

DEVELOPMENT OF OTOLITHS-INCORPORATED SODIUM ALGINATE AND GELATIN-BASED SCAFFOLDS FOR BONE REGENERATION APPLICATIONS

<h3>Objectives</h3> To develop scaffolds based on gelatin and sodium alginate containing otoliths from <i>Cynoscion acoupa</i> for bone repair applications. <h3>Study Design</h3> Otoliths were characterized by X-ray fluorescence spectrometry and particle size. The scaffolds were produced by freeze-drying. The otoliths were incorporated into the polymeric scaffolds (AlgOTL and GelOTL) and characterized by thermogravimetric analysis (TGA/DTG)-differential themogravimetry, differential scanning calorimetry (DSC), spectroscopy in the infrared region (Fourier transform infrared [FTIR]), swelling, and scanning electron microscopy (SEM). The biomaterials' cytotoxicity was analyzed in macrophage lines J774.G8 and osteoblasts MC3T3-E1. <h3>Results</h3> TGA/DTG, DSC, and FTIR analysis suggested proper otolith incorporation into the polymeric matrices. SEM demonstrated the porous homogeneous 3D structure of the scaffold, and the presence of homogeneously distributed otolith-derived crystalloids over the materials' surface. The GEL/OTL swelling (63.54 ± 3.0%) was greater than ALG/OTL (13.36 ± 9.9%; <i>P</i> < .001). The viability of J774.G8 macrophages treated with GELATINBASED/OTOLITHS (GEL/OTL) and SODIUM ALGINATE/OTOLITHS (ALG/OTL) was statistically similar to the control group (<i>P</i> > 0.05). However, the MC3T3-E1 osteoblasts growth rate after 48 hours was significantly higher in ALG/OTL than in GEL/OTL (<i>P</i> < 0.05). <h3>Conclusions</h3> The ALG/OTL scaffold is a potential biomaterial to be used in further bone regeneration research.

The Auxiliary Role of Heparin in Bone Regeneration and its Application in Bone Substitute Materials.

Bone regeneration in large segmental defects depends on the action of osteoblasts and the ingrowth of new blood vessels. Therefore, it is important to promote the release of osteogenic/angiogenic growth factors. Since the discovery of heparin, its anticoagulant, anti-inflammatory, and anticancer functions have been extensively studied for over a century. Although the application of heparin is widely used in the orthopedic field, its auxiliary effect on bone regeneration is yet to be unveiled. Specifically, approximately one-third of the transforming growth factor (TGF) superfamily is bound to heparin and heparan sulfate, among which TGF-β1, TGF-β2, and bone morphogenetic protein (BMP) are the most common growth factors used. In addition, heparin can also improve the delivery and retention of BMP-2 in vivo promoting the healing of large bone defects at hyper physiological doses. In blood vessel formation, heparin still plays an integral part of fracture healing by cooperating with the platelet-derived growth factor (PDGF). Importantly, since heparin binds to growth factors and release components in nanomaterials, it can significantly facilitate the controlled release and retention of growth factors [such as fibroblast growth factor (FGF), BMP, and PDGF] in vivo. Consequently, the knowledge of scaffolds or delivery systems composed of heparin and different biomaterials (including organic, inorganic, metal, and natural polymers) is vital for material-guided bone regeneration research. This study systematically reviews the structural properties and auxiliary functions of heparin, with an emphasis on bone regeneration and its application in biomaterials under physiological conditions.

In situ measurement of the isoplanatic patch for imaging through intact bone.

Wavefront-shaping (WS) enables imaging through scattering tissues like bone, which is important for neuroscience and bone-regeneration research. WS corrects for the optical aberrations at a given depth and field-of-view (FOV) within the sample; the extent of the validity of which is limited to a region known as the isoplanatic patch (IP). Knowing this parameter helps to estimate the number of corrections needed for WS imaging over a given FOV. In this paper, we first present direct transmissive measurement of murine skull IP using digital optical phase conjugation based focusing. Second, we extend our previously reported phase accumulation ray tracing (PART) method to provide in-situ in-silico estimation of IP, called correlative PART (cPART). Our results show an IP range of 1 to 3 μm for mice within an age range of 8 to 14 days old and 1.00 ± 0.25 μm in a 12-week old adult skull. Consistency between the two measurement approaches indicates that cPART can be used to approximate the IP before a WS experiment, which can be used to calculate the number of corrections required within a given field of view.

Overcoming barriers confronting application of protein therapeutics in bone fracture healing.

Bone fracture is a major contributor to debilitation and death among patients with bone diseases. Thus, osteogenic protein therapeutics and their delivery to bone have been extensively researched as strategies to accelerate fracture healing. To prevent morbidity and mortality of fractures, which occur frequently in the aging population, there is a critical need for development of first-line therapeutics. Bone morphogenic protein-2 (BMP-2) has been at the forefront of bone regeneration research for its potent osteoinduction, despite safety concerns and biophysiological obstacles of delivery to bone. However, continued pursuit of osteoinductive proteins as a therapeutic option is largely aided by drug delivery systems, playing an imperative role in enhancing safety and efficacy. In this work, we highlighted several types of drug delivery platforms and their biomaterials, to evaluate the suitability in overcoming challenges of therapeutic protein delivery for bone regeneration. To showcase the clinical considerations for each type of platform, we have assessed the most common route of administration strategies for bone regeneration, classifying the platforms as implantable or injectable. Additionally, we have analyzed the commonly utilized models and methodology for safety and efficacy evaluation of these osteogenic protein-loaded systems, to present clinical opinions for future directions of research in this field. It is hoped that this review will promote research and development of clinically translatable osteogenic protein therapeutics, while targeting first-line treatment status for achieving desired outcomes of fracture healing. Graphical abstract.

Proteomic and Transcriptomic Approaches for Studying Bone Regeneration in Health and Systemically Compromised Conditions.

Bone regeneration is a complex biological process, where the molecular mechanisms are only partially understood. In an ageing population, where the prevalence of chronic diseases with an impact on bone metabolism is increasing, it becomes crucial to identify new strategies that would improve regenerative outcomes also in medically compromised patients. In this context, omics are demonstrating a great potential, as they offer new insights on the molecular mechanisms regulating physiologic/pathologic bone healing and, at the same time, allow the identification of new diagnostic and therapeutic targets. This review provides an overview on the current evidence on the use of transcriptomic and proteomic approaches in bone regeneration research, particularly in relation to type 1 diabetes and osteoporosis, and discusses future scenarios and potential benefits and limitations on the integration of multi-omics. It is suggested that future research will leverage the synergy of omics with statistical modeling and bioinformatics to prompt the understanding of the biology underpinning bone formation in health and medically compromised conditions. With an eye toward personalized medicine, new strategies combining the mining of large datasets and bioinformatic data with a detailed characterization of relevant phenotypes will need to be pursued to further the understanding of disease mechanisms.

High Concentration of Sodium Metasilicate Impairs Autophagic Flux and Induces Apoptosis in Human Umbilical Vein Endothelial Cells.

Silicon-doped materials have been widely used in bone regeneration research; however, a consensus on the safety range of silicon ions has not been reached and its toxicity mechanism remains to be further elucidated. This study aims to explore whether high level of sodium metasilicate can induce toxicity effect in human umbilical vein endothelial cells (HUVEC) and the role of autophagy and apoptosis in its toxic mechanism. HUVEC was treated with different level of high silicon and then investigated with respect to morphologic change, cell viability, immunofluorescence, the level of autophagy, and apoptosis-related protein. Moreover, bafilomycin A1 (Baf A1) was applied to detect whether autophagic flux is disrupted, and 3-methyladenine (3-MA, an autophagy inhibitor) was used to determine the relationship between autophagy and apoptosis. Results demonstrated that high-level silicon induced cell viability to decrease; LC3-II, p62, and apoptosis-related proteins were up-regulated after exposure to high-dose silicon (sodium metasilicate concentration more than 1mM). There is no significant difference in LC3-II and p62 between Baf A1 and sodium metasilicate-exposed group. Besides, 3-MA further increased the apoptotic rate by inhibiting autophagy after high silicon exposure. Collectively, high concentration of silicon can impair autophagy and induce apoptosis in human umbilical vein endothelial cells, and autophagy may play a protective role in HUVEC apoptosis. Furthermore, silicon concentration used in HUVEC should not be more than 1mM.

Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles

NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein⿿s bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research.

PH-activated delivery of growth factors from keratin-PEG gels for bone tissue engineering

Event Abstract Back to Event pH-activated delivery of growth factors from keratin-PEG gels for bone tissue engineering Roche De Guzman1 1 Hofstra University, Department of Engineering, United States Polyethylene glycol (PEG) and keratin (KTN) proteins are hydrophilic biocompatible materials. Gels and scaffolds produced by crosslinking of KTN to PEG (KTN-PEG) have great potential applications as degradable temporary matrices for bone regeneration research. KTN-PEG hydrogels were fabricated by photopolymerization reaction of thiols and acrylates. These constructs were found to be stable but slowly-degradable due to protein hydrolysis. Test globular proteins (Alb = albumin, Hem = hemoglobin, Lys = lysozyme) with different isoelectric points (pIs) were absorbed and their release kinetics assessed. In physiological pH 7.4, the loaded protein release rates were charge-dependent with rate profiles being: Alb > Hem > Lys (Fig. 1). However in acidic pH 4 where all proteins carry positive net charges, the release rates were determined to be size-dependent: Lys (14-kDa) > Hem (64-kDa) > Alb (66-kDa), suggesting that proteins with basic pIs like most growth factors (GFs) can be burst released in acidic pH. GFs: bone morphogenetic protein-2 (BMP-2; pI = 9) and chondromodulin-1 (Chm-1; pI = 7.5) were absorbed into the KTN-PEG bulk, washed with culture media at pH 7.4 and 4, and human adipose tissue-derived mesenchymal stem cells (hMSCs) cultured and induced using osteogenic differentiation medium. Cultured hMSCs attached and proliferated (Fig. 2) onto the KTN-PEG substrates. Osteogenic differentiation on gels with BMP-2 and Chm-1 produced more Alizarin Red S staining indicative of faster calcification and better hMSCs osteogenesis compared to groups without GFs. Gels activated in acidic pH to release the ionically-bound GFs had trends suggesting improved differentiation. This study demonstrated that GFs absorbed into the material can be efficiently freed via electrostatic repulsion in the acidic environment, which can potentially lead to recruitment, proliferation and differentiation of repair stem cells in an in vivo bone-defect model. Keywords: Cell Differentiation, Hydrogel, 3D scaffold, Polymeric material Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials for therapeutic delivery Citation: De Guzman R (2016). pH-activated delivery of growth factors from keratin-PEG gels for bone tissue engineering. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02235 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Roche De Guzman Google Roche De Guzman Google Scholar Roche De Guzman PubMed Roche De Guzman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Expression of Nucleotide-Binding Oligomerization Domain-Like Receptor in Oral Lichen Planus

Wonkwang Bone Regeneration Research Institute, Wonkwang University, Daejeon, Korea Cherubism is a skeletal dysplasia characterized by progressive, painless, bilateral and symmetric lesions limited to the jaws. The lesions subsequently begin to regress, fill with bone and remodel until age 30. Because cherubism is usually self-limiting, operative treatment may not be necessary. However, surgical intervention with curettage, contouring or resection may be indicated for functional or aesthetic reasons. Surgical procedures are usually performed when the disease not activated. Tissue engineering uses scaffolds as delivery vehicles for transplanted cells to restore function and replace damaged tissue. Tissue engineering using fibrin scaffolds as delievery vehicles can be restore function and replace damaged tissue on oral maxillofacial area. This is the first report of a successful esthetic restoration using autologous human bone marrow mesenchymal stem cell for cherubism patient after corticotomy and curretage on both mandibular lesions. Support: This research was supported by iPET, Ministry of Agriculture, Food and Rural Affairs (112092-03-2-HD020).

Graphene: A Versatile Carbon-Based Material for Bone Tissue Engineering.

The development of materials and strategies that can influence stem cell attachment, proliferation, and differentiation towards osteoblasts is of high interest to promote faster healing and reconstructions of large bone defects. Graphene and its derivatives (graphene oxide and reduced graphene oxide) have received increasing attention for biomedical applications as they present remarkable properties such as high surface area, high mechanical strength, and ease of functionalization. These biocompatible carbon-based materials can induce and sustain stem cell growth and differentiation into various lineages. Furthermore, graphene has the ability to promote and enhance osteogenic differentiation making it an interesting material for bone regeneration research. This paper will review the important advances in the ability of graphene and its related forms to induce stem cells differentiation into osteogenic lineages.

Poly (glycerol sebacate) elastomer supports osteogenic phenotype for bone engineering applications

For bone engineering, the optimal scaffolding material and composition has yet to be elucidated. In this study, we investigated poly (glycerol sebacate) (PGS), an elastomer known primarily for its soft tissue regeneration ability, as a suitable substrate to support osteo-precursor cell attachment and function. We synthesized PGS in the form of sheets where MC3T3-E1 cells were seeded in three different densities of 25 000, 50 000 and 100 000 cells mm−3 and we investigated the cells/scaffold constructs for their cellular proliferation, matrix deposition, maturation, mineralization and their mechanical compression strength at 24 h and two and four weeks. MC3T3-E1 cells proliferated, synthesized a collagenous matrix and expressed osteogenic markers Runx2, bone sialoprotein and osteocalcin according to their initial seeding density on PGS. We conclude that PGS can support the osteoblastic phenotype in vitro and is a promising osteoconductive substrate for bone regeneration research and for future clinical translation.

Micro/Nanotexturing and Bioactivation Strategies to Design Composite Scaffolds and ECM‐Like Analogues

SummaryThe current landscape of bone regeneration research has focused on novel processing techniques for scaffolds and the employment of nanostructured and bioactive materials to trigger specific cell function in osteogenic way. The investigation of novel technological methods and materials may guide towards more promising and still unexplored strategies to fabricate innovative scaffolds for hard tissue regeneration. Here, we focus on recent advancements in the area of tissue‐engineered scaffold fabrication with emphasis on polymer/ceramic composites and micro and/or nanotexturing processes (i.e, electrospinning) as well as their combinations. In particular, different approaches based on the design of bioactive micro/nanonanocomposites, hybrids and nanofibers will be presented with some promise for engineering three‐dimensional ECM analogues of bone.

A murine femoral segmental defect model for bone tissue engineering using a novel rigid internal fixation system

BackgroundAs a model animal, the mouse has already been widely used in bone-related research. However, there is a lack of ideal long bone segmental defect mouse model. Since external fixation has disadvantages of heavy weight, penetrating the skin, and hampering mobility, an internal fixation device is probably more preferable to maintain the segmental bone defect. The aim of this study was to establish a simple, reproducible, and standardized murine critical-size defect model through designing an internal fixation system, verifying its adaptability, and investigating the critical size of femoral segmental defect. MethodsBy utilizing computer-aided measuring and processing system, anatomical data of adult C57BL/6 mouse femur was obtained, and a plate-bolts system was designed for rigid fixation. The plate and screws were fixed in 67 mice and 1.5 or 2.0 mm defect gaps were created in the femoral midshaft. Compression and three-point bending of bone-implant construct were tested in mice at 0, 2, 5, and 12 wk postoperative to test the biomechanical stability. X-ray, micro-computed tomography, and histology were used to investigate the defect healing process. ResultsThe plate- and screws-fitted mouse femur and unilateral or bilateral operation had seemingly no adverse impact on the mouse in general. Mechanical tests indicated that there were no significant differences between the bone-implant construct and intact femur in compression and three-point bending loading. Micro-computed tomography scanning showed the bone mineral density had not been affected by the implantation of fixation device. There was no union of the 2.0 mm segmental defect in 12-wk period. ConclusionUsing the specifically designed rigid internal fixation device, a segmental defect size of 2.0 mm in C57BL/6 mouse femur will show nonunion and can serve as a critical defect size for bone tissue engineering and bone regeneration research.

Clinically applied models of bone regeneration in tissue engineering research.

The development of new strategies for the engineering of bone regeneration requires appropriate model systems. Selection of the best model for testing a new technology depends on a host of factors. In general, the best model system is the one which most closely mimics the clinical situation for which this technology is being developed, will not heal spontaneously unless the technology is used, and will not heal when another technology is used if that technology is less advanced than the one being tested. For the purposes of developing new strategies for bone regeneration, systems which can be considered include those which model normal fracture healing, the segmental loss of bone or critical size defects, and various forms of nonunions in which fracture healing is perturbed either by mechanical, metabolic, or neurologic means. Careful experimental design and selection of the appropriate model system will enhance scientific efforts in bone regeneration research.