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Clinical Orthopaedics and Related... Nov 2011
Topics: Bone Regeneration; Fracture Healing; Fractures, Bone; Humans
PubMed: 21833658
DOI: 10.1007/s11999-011-2010-z -
Current Opinion in Biotechnology Aug 2016While experimental bone regeneration approaches commonly employ cells, technological hurdles prevent translation of these therapies. Alternatively, emulating the... (Review)
Review
While experimental bone regeneration approaches commonly employ cells, technological hurdles prevent translation of these therapies. Alternatively, emulating the spatiotemporal cascade of endogenous factors through controlled drug delivery may provide superior bone regenerative approaches. Surgically placed drug depots have clinical indications. Additionally, noninvasive systemic delivery can be used as needed for poorly healing bone injuries. However, a major hurdle for systemic delivery is poor bone biodistribution of drugs. Thus, peptides, aptamers, and phosphate-rich compounds with specificity toward proteins, cells, and molecules within the regenerative bone microenvironment may enable the design of targeted carriers with bone biodistribution greater than that achieved by drug alone. These carriers, combined with osteoregenerative drugs and/or stimuli-sensitive linkers, may enhance bone regeneration while minimizing off-target tissue effects.
Topics: Animals; Bone Regeneration; Bone and Bones; Drug Delivery Systems; Humans; Intercellular Signaling Peptides and Proteins; Tissue Engineering
PubMed: 27064433
DOI: 10.1016/j.copbio.2016.02.029 -
International Journal of Molecular... Mar 2018The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based... (Review)
Review
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 . 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.
Topics: Animals; Bone Regeneration; Bone Substitutes; Humans; Metals; Osteogenesis
PubMed: 29534546
DOI: 10.3390/ijms19030826 -
ACS Biomaterials Science & Engineering Sep 2023Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been... (Review)
Review
Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.
Topics: Tissue Engineering; Biocompatible Materials; Bone Regeneration; Bone and Bones; Peptides
PubMed: 37585562
DOI: 10.1021/acsbiomaterials.3c00609 -
Acta Biomaterialia Oct 2021The regulatory functions of the immune response in tissue healing, repair, and regeneration have been evidenced in the last decade. Immune cells play central roles in... (Review)
Review
The regulatory functions of the immune response in tissue healing, repair, and regeneration have been evidenced in the last decade. Immune cells play central roles in immune responses toward inducing favorable tissue regenerative processes. Modulating and controlling the immune cell responses (particularly macrophages) is an emerging approach to enhance tissue regeneration. Bioactive glasses (BGs) are multifunctional materials exhibiting osteogenic, angiogenic, and antibacterial properties, being increasingly investigated for various tissue regeneration scenarios, including bone regeneration and wound healing. On the other hand, the immunomodulatory effects of BGs in relation to regenerating tissues have started to be understood, and key knowledge is emerging. This is the first review article summarizing the immunomodulatory effects of BGs for tissue repair and regeneration. The immune response to BGs is firstly introduced, discussing potential mechanisms regarding the immunomodulation effects induced by BGs. Moreover, the interactions between the immune cells involved in the immunomodulation process and BGs (dissolution products) are summarized in detail. Particularly, a well-regulated and timely switch of macrophage phenotype from pro-inflammatory to anti-inflammatory is crucial to constructive tissue regeneration through modulating osteogenesis, osteoclastogenesis, and angiogenesis. The influence of BG characteristics on macrophage responses is discussed. We highlight the strategies employed to harness macrophage responses for enhanced tissue regeneration, including the incorporation of active ions, surface functionalization, and controlled release of immunomodulatory molecules. Finally, we conclude with our perspectives on future research challenges and directions in the emerging field of immunomodulatory BGs for tissue regeneration. STATEMENT OF SIGNIFICANCE: Immunomodulatory effects of bioactive glasses (BGs) in relation to bone regeneration and wound healing have started to be understood. We summarize those studies which have focused on immunomodulatory BGs for tissue regeneration. We first introduce the potential mechanisms of the immunomodulation effects induced by BGs. Interactions between the cells involved in immunomodulation processes and BGs (and their dissolution products, biologically active ions) are elaborated. We highlight the strategies employed to modulate macrophage responses for enhancing tissue regeneration, including incorporation of active ions, surface functionalization, and controlled release of immunomodulatory agents. This is the first review article summarizing and outlining the immunomodulatory effects of BGs for tissue regeneration. We anticipate that increasing research efforts will start to emerge in the area of immunomodulatory BGs.
Topics: Bone Regeneration; Immunity; Immunomodulation; Osteogenesis; Wound Healing
PubMed: 34418539
DOI: 10.1016/j.actbio.2021.08.023 -
Periodontology 2000 Feb 2024The recognition and importance of immune cells during bone regeneration, including around bone biomaterials, has led to the development of an entire field termed... (Review)
Review
The recognition and importance of immune cells during bone regeneration, including around bone biomaterials, has led to the development of an entire field termed "osteoimmunology," which focuses on the connection and interplay between the skeletal system and immune cells. Most studies have focused on the "osteogenic" capacity of various types of bone biomaterials, and much less focus has been placed on immune cells despite being the first cell type in contact with implantable devices. Thus, the amount of literature generated to date on this topic makes it challenging to extract needed information. This review article serves as a guide highlighting advancements made in the field of osteoimmunology emphasizing the role of the osteoimmunomodulatory properties of biomaterials and their impact on osteoinduction. First, the various immune cell types involved in bone biomaterial integration are discussed, including the prominent role of osteal macrophages (OsteoMacs) during bone regeneration. Thereafter, key biomaterial properties, including topography, wettability, surface charge, and adsorption of cytokines, growth factors, ions, and other bioactive molecules, are discussed in terms of their impact on immune responses. These findings highlight and recognize the importance of the immune system and osteoimmunology, leading to a shift in the traditional models used to understand and evaluate biomaterials for bone regeneration.
Topics: Humans; Biocompatible Materials; Bone Regeneration; Osteogenesis; Macrophages; Bone and Bones; Cytokines; Osseointegration; Bone Substitutes; Animals
PubMed: 37658591
DOI: 10.1111/prd.12519 -
Current Osteoporosis Reports Feb 2018Exosomes are membrane vesicles that are released by most cell types into the extracellular environment. The purpose of this article is to discuss the main morphological... (Review)
Review
PURPOSE OF REVIEW
Exosomes are membrane vesicles that are released by most cell types into the extracellular environment. The purpose of this article is to discuss the main morphological features and contents of bone-derived exosomes, as well as their major isolation and physical characterization techniques. Furthermore, we present various scenarios and discuss potential clinical applications of bone-derived exosomes in bone repair and regeneration.
RECENT FINDINGS
Exosomes were believed to be nanosized vesicles derived from the multivesicular body. Reports now suggest that nanovesicles could bud directly from the plasma membrane. However, the exosome cargo is cell-type specific and is derived from the parent cell. In the bone matrix, several intracellular proteins lacking a signal peptide are transported to the ECM by exosomes. Besides proteins, several mRNA, miRNA, and lipids are exported to the ECM by bone cells and bone marrow stromal cells. Recent evidence suggests that several of the functional components in the cargo could regulate processes of bone formation, inhibit osteoclast activity, and promote fracture repair. Exosomes are powerful cellular molecular machines produced without human intervention and packaged with physiological cargo that could be utilized for molecular therapy in several skeletal disorders such as osteoporosis, osteogenesis imperfecta, and fracture healing. Although much work has been done, there is a lot of information that is still unknown, as exosomes contain a multitude of molecules whose identity and function have yet to be identified.
Topics: Animals; Bone Matrix; Bone Regeneration; Exosomes; Humans; Osteogenesis
PubMed: 29372401
DOI: 10.1007/s11914-018-0419-y -
International Journal of Oral Science Jan 2022Distraction osteogenesis (DO) is widely used for bone tissue engineering technology. Immune regulations play important roles in the process of DO like other bone... (Review)
Review
Distraction osteogenesis (DO) is widely used for bone tissue engineering technology. Immune regulations play important roles in the process of DO like other bone regeneration mechanisms. Compared with others, the immune regulation processes of DO have their distinct features. In this review, we summarized the immune-related events including changes in and effects of immune cells, immune-related cytokines, and signaling pathways at different periods in the process of DO. We aim to elucidated our understanding and unknowns about the immunomodulatory role of DO. The goal of this is to use the known knowledge to further modify existing methods of DO, and to develop novel DO strategies in our unknown areas through more detailed studies of the work we have done.
Topics: Bone Regeneration; Bone and Bones; Osteogenesis; Osteogenesis, Distraction; Tissue Engineering
PubMed: 35067679
DOI: 10.1038/s41368-021-00156-y -
Journal of Clinical Periodontology Jun 2019To review the knowledge on the mechanisms controlling membrane-host interactions in guided bone regeneration (GBR) and investigate the possible role of GBR membranes as... (Review)
Review
AIM
To review the knowledge on the mechanisms controlling membrane-host interactions in guided bone regeneration (GBR) and investigate the possible role of GBR membranes as bioactive compartments in addition to their established role as barriers.
MATERIALS AND METHODS
A narrative review was utilized based on in vitro, in vivo and available clinical studies on the cellular and molecular mechanisms underlying GBR and the possible bioactive role of membranes.
RESULTS
Emerging data demonstrate that the membrane contributes bioactively to the regeneration of underlying defects. The cellular and molecular activities in the membrane are intimately linked to the promoted bone regeneration in the underlying defect. Along with the native bioactivity of GBR membranes, incorporating growth factors and cells in membranes or with graft materials may augment the regenerative processes in underlying defects.
CONCLUSION
In parallel with its barrier function, the membrane plays an active role in hosting and modulating the molecular activities of the membrane-associated cells during GBR. The biological events in the membrane are linked to the bone regenerative and remodelling processes in the underlying defect. Furthermore, the bone-promoting environments in the two compartments can likely be boosted by strategies targeting both material aspects of the membrane and host tissue responses.
Topics: Biocompatible Materials; Bone Regeneration; Guided Tissue Regeneration; Membranes, Artificial
PubMed: 30667525
DOI: 10.1111/jcpe.13068 -
Dental Materials : Official Publication... Apr 2015The focus of this review is to summarize recent advances on regenerative technologies (scaffolding matrices, cell/gene therapy and biologic drug delivery) to promote... (Review)
Review
OBJECTIVE
The focus of this review is to summarize recent advances on regenerative technologies (scaffolding matrices, cell/gene therapy and biologic drug delivery) to promote reconstruction of tooth and dental implant-associated bone defects.
METHODS
An overview of scaffolds developed for application in bone regeneration is presented with an emphasis on identifying the primary criteria required for optimized scaffold design for the purpose of regenerating physiologically functional osseous tissues. Growth factors and other biologics with clinical potential for osteogenesis are examined, with a comprehensive assessment of pre-clinical and clinical studies. Potential novel improvements to current matrix-based delivery platforms for increased control of growth factor spatiotemporal release kinetics are highlighting including recent advancements in stem cell and gene therapy.
RESULTS
An analysis of existing scaffold materials, their strategic design for tissue regeneration, and use of growth factors for improved bone formation in oral regenerative therapies results in the identification of current limitations and required improvements to continue moving the field of bone tissue engineering forward into the clinical arena.
SIGNIFICANCE
Development of optimized scaffolding matrices for the predictable regeneration of structurally and physiologically functional osseous tissues is still an elusive goal. The introduction of growth factor biologics and cells has the potential to improve the biomimetic properties and regenerative potential of scaffold-based delivery platforms for next-generation patient-specific treatments with greater clinical outcome predictability.
Topics: Bone Regeneration; Humans; Mouth; Osseointegration; Tissue Engineering
PubMed: 25701146
DOI: 10.1016/j.dental.2015.01.006