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Journal of the Mechanical Behavior of... Oct 2020All levels of the unique hierarchical structure of bone, consisting of collagen and hydroxyapatite crystals at the nanoscale to osteon/lamellae structures at the... (Review)
Review
All levels of the unique hierarchical structure of bone, consisting of collagen and hydroxyapatite crystals at the nanoscale to osteon/lamellae structures at the microscale, contribute to its characteristic toughness and material properties. Elements of bone's density and size contribute to bone quantity (or bone mass), whereas elements of bone's material composition, material properties, internal structure, and organization describe bone quality. Bone quantity and quality can be degraded by factors such as aging, disease, treatments, and irradiation, compromising its ability to resist fracture and sustain loading. Accessing the morphology and architecture of bone at the microscale to quantify microstructural features and assess the degree of mineralization and path of crack propagation in bone provides crucial information on how these factors are influencing bone quantity and quality. Synchrotron radiation micro-computed tomography (SRμCT) was first used to assess bone structure at the end of the 1990's. One of the main advantages of the technique is that it enables accurate three-dimensional (3D), non-destructive quantification of structure while traditional histomorphometry on histological sections is inherantly destructive to the sample and two-dimensional (2D). Additionally, SRμCT uses monochromatic, high-flux X-ray beams to provide high-resolution and high-contrast imaging of bone samples. This allows the quantification of small microstructural features (e.g. osteocyte lacunae, canals, trabeculae, microcracks) and direct gray value compositional mapping (e.g. mineral quantification, cement lines) with greater speed and fidelity than lab-based micro-computed tomography. In this article, we review how SRμCT has been applied to bone research to elucidate the mechanisms by which bone aging, disease, and other factors affect bone fragility and resistance to fracture.
Topics: Bone Density; Bone and Bones; Haversian System; Synchrotrons; X-Ray Microtomography
PubMed: 32957194
DOI: 10.1016/j.jmbbm.2020.103887 -
Acta Biomaterialia May 2023Bone fragility is a profound complication of type 1 diabetes mellitus (T1DM), increasing patient morbidity. Within the mineralized bone matrix, osteocytes build a...
Bone fragility is a profound complication of type 1 diabetes mellitus (T1DM), increasing patient morbidity. Within the mineralized bone matrix, osteocytes build a mechanosensitive network that orchestrates bone remodeling; thus, osteocyte viability is crucial for maintaining bone homeostasis. In human cortical bone specimens from individuals with T1DM, we found signs of accelerated osteocyte apoptosis and local mineralization of osteocyte lacunae (micropetrosis) compared with samples from age-matched controls. Such morphological changes were seen in the relatively young osteonal bone matrix on the periosteal side, and micropetrosis coincided with microdamage accumulation, implying that T1DM drives local skeletal aging and thereby impairs the biomechanical competence of the bone tissue. The consequent dysfunction of the osteocyte network hampers bone remodeling and decreases bone repair mechanisms, potentially contributing to the enhanced fracture risk seen in individuals with T1DM. STATEMENT OF SIGNIFICANCE: Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease that causes hyperglycemia. Increased bone fragility is one of the complications associated with T1DM. Our latest study on T1DM-affected human cortical bone identified the viability of osteocytes, the primary bone cells, as a potentially critical factor in T1DM-bone disease. We linked T1DM with increased osteocyte apoptosis and local accumulation of mineralized lacunar spaces and microdamage. Such structural changes in bone tissue suggest that T1DM speeds up the adverse effects of aging, leading to the premature death of osteocytes and potentially contributing to diabetes-related bone fragility.
Topics: Humans; Osteocytes; Diabetes Mellitus, Type 1; Aging; Bone and Bones; Apoptosis
PubMed: 36878337
DOI: 10.1016/j.actbio.2023.02.037 -
American Journal of Biological... Oct 2023In modern bone biology, the term "remodeling" generally refers to internal bone turnover that creates secondary osteons. However, it is also widely used by skeletal... (Review)
Review
OBJECTIVES
In modern bone biology, the term "remodeling" generally refers to internal bone turnover that creates secondary osteons. However, it is also widely used by skeletal biologists, including biological anthropologists as a catch-all term to refer to different skeletal changes. In this review, we investigated how "remodeling" is used across topics on skeletal biology in biological anthropology to demonstrate potential problems with such pervasive use of a generalized term.
METHODS
Using PubMed and Google Scholar, we selected and reviewed 205 articles that use the term remodeling to describe skeletal processes and have anthropological implications. Nine edited volumes were also reviewed as examples of collaborative work by different experts to demonstrate the diverse and extensive use of the term remodeling.
RESULTS
Four general meanings of bone "remodeling" were identified, namely, internal turnover, functional adaptation, fracture repair, and growth remodeling. Additionally, remodeling is also used to refer to a broad array of pathological skeletal changes.
DISCUSSION
Although we initially identified four general meanings of bone remodeling, they are not mutually exclusive and often occur in combination. The term "remodeling" has become an extensively used catch-all term to refer to different processes and outcomes of skeletal changes, which inevitably lead to misunderstanding and a loss of information. Such ambiguity and confusion are potentially problematic as the field of biological anthropology becomes increasingly multidisciplinary. Therefore, we advocate for precise, context-specific definitions and explanations of bone remodeling as it continues to be used across disciplines within and beyond biological anthropology.
Topics: Anthropology; Bone and Bones; Bone Remodeling
PubMed: 37515465
DOI: 10.1002/ajpa.24825 -
Seminars in Musculoskeletal Radiology Aug 2020Bone is a composite material consisting of mineral, organic matrix, and water. Water in bone can be categorized as bound water (BW), which is bound to bone mineral and... (Review)
Review
Bone is a composite material consisting of mineral, organic matrix, and water. Water in bone can be categorized as bound water (BW), which is bound to bone mineral and organic matrix, or as pore water (PW), which resides in Haversian canals as well as in lacunae and canaliculi. Bone is generally classified into two types: cortical bone and trabecular bone. Cortical bone is much denser than trabecular bone that is surrounded by marrow and fat. Magnetic resonance (MR) imaging has been increasingly used for noninvasive assessment of both cortical bone and trabecular bone. Bone typically appears as a signal void with conventional MR sequences because of its short T2*. Ultrashort echo time (UTE) sequences with echo times 100 to 1,000 times shorter than those of conventional sequences allow direct imaging of BW and PW in bone. This article summarizes several quantitative MR techniques recently developed for bone evaluation. Specifically, we discuss the use of UTE and adiabatic inversion recovery prepared UTE sequences to quantify BW and PW, UTE magnetization transfer sequences to quantify collagen backbone protons, UTE quantitative susceptibility mapping sequences to assess bone mineral, and conventional sequences for high-resolution imaging of PW as well as the evaluation of trabecular bone architecture.
Topics: Cancellous Bone; Contrast Media; Cortical Bone; Humans; Image Enhancement; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging
PubMed: 32992367
DOI: 10.1055/s-0040-1710355 -
Frontiers in Immunology 2020Osteoporosis stems from an unbalance between bone mineral resorption and deposition. Among the numerous cellular players responsible for this unbalance bone marrow (BM)... (Review)
Review
Osteoporosis stems from an unbalance between bone mineral resorption and deposition. Among the numerous cellular players responsible for this unbalance bone marrow (BM) monocytes/macrophages, mast cells, T and B lymphocytes, and dendritic cells play a key role in regulating osteoclasts, osteoblasts, and their progenitor cells through interactions occurring in the context of the different bone compartments (cancellous and cortical). Therefore, the microtopography of immune cells inside trabecular and compact bone is expected to play a relevant role in setting initial sites of osteoporotic lesion. Indeed, in physiological conditions, each immune cell type preferentially occupies either endosteal, subendosteal, central, and/or perisinusoidal regions of the BM. However, in the presence of an activation, immune cells recirculate throughout these different microanatomical areas giving rise to a specific distribution. As a result, the trabeculae of the cancellous bone and endosteal free edge of the diaphyseal case emerge as the primary anatomical targets of their osteoporotic action. Immune cells may also transit from the BM to the depth of the compact bone, thanks to the efferent venous capillaries coursing in the Haversian and Volkmann canals. Consistently, the innermost parts of the osteons and the periosteum are later involved by their immunomodulatory action, becoming another site of mineral reabsorption in the course of an osteoporotic insult. The novelty of our updating is to highlight the microtopography of bone immune cells in the cancellous and cortical compartments in relation to the most consistent data on their action in bone remodeling, to offer a mechanist perspective useful to dissect their role in the osteoporotic process, including bone damage derived from the immunomodulatory effects of endocrine disrupting chemicals.
Topics: Animals; Bone Remodeling; Bone and Bones; Endocrine Disruptors; Humans; Immune System; Immunologic Factors; Osteoporosis
PubMed: 33013826
DOI: 10.3389/fimmu.2020.01737 -
Surgical and Radiologic Anatomy : SRA Aug 2020The aim of this study is to describe the number and location of the nutrient foramina in human scapulae which can minimize blood loss during surgery.
PURPOSE
The aim of this study is to describe the number and location of the nutrient foramina in human scapulae which can minimize blood loss during surgery.
METHODS
30 cadaveric scapulae were macerated to denude the skeletal tissue. The nutrient foramina of 0.51 mm and larger were identified and labeled by adhering glass beads. CT scans of these scapulae were segmented resulting in a surface model of each scapula and the location of the labeled nutrient foramina. All scapulae were scaled to the same size projecting the nutrient foramina onto one representative scapular model.
RESULTS
Average number of nutrient foramina per scapula was 5.3 (0-10). The most common location was in the supraspinous fossa (29.7%). On the costal surface of the scapula, most nutrient foramina were found directly inferior to the suprascapular notch. On the posterior surface, the nutrient foramina were identified under the spine of the scapula in a somewhat similar fashion as those on the costal surface. Nutrient foramina were least present in the peri-glenoid area.
CONCLUSION
Ninety percent of scapulae have more than one nutrient foramen. They are located in specific areas, on both the posterior and costal surface.
Topics: Adult; Aged; Aged, 80 and over; Blood Loss, Surgical; Cadaver; Dissection; Female; Fiducial Markers; Haversian System; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Scapula; Tomography, X-Ray Computed
PubMed: 32112283
DOI: 10.1007/s00276-020-02441-7 -
Regulation of an osteon-like concentric microgrooved surface on osteogenesis and osteoclastogenesis.Biomaterials Sep 2019Topographical cues provided by micropatterns on material surfaces have been demonstrated to control multiple cell functions. However, the majority of currently studied...
Topographical cues provided by micropatterns on material surfaces have been demonstrated to control multiple cell functions. However, the majority of currently studied micropatterns fail to recapitulate the key characteristics of an osteon, which is the structural unit of natural cortical bone. Thus, in the present study, a micropatterned polycaprolactone (PCL) surface comprising a series of concentric circular microgrooves was fabricated by combining photolithography with the melt-casting method to mimic the concentric structure of an osteon in a two-dimensional setting. By culturing mouse mesenchymal stem cells (mMSCs) and osteoclast progenitor cells (RAW264.7 cells) on the osteon-like concentric microgrooved surface, the effects of this micropatterned surface on the osteogenesis of mMSCs and the osteoclastogenesis of RAW264.7 cells were systematically investigated. Osteoclastogenic differentiation was significantly inhibited in RAW264.7 cells on the fabricated osteon-like concentric microgrooved surface compared to that on the parallel linear microgrooved and flat surfaces, as indicated by the downregulated expression of key osteoclast-specific function genes (TRAP, CATK and MMP9), the lower activity of TRAP and less formation of TRAP-positive multinucleated giant osteoclasts. Further investigation indicated that RANK-NFκB signaling may have been involved in mediating the inhibited osteoclastogenesis of RAW264.7 cells by the osteon-like concentric microgrooved surface. In addition, the osteon-like concentric microgrooved surface greatly modulated the osteoclastogenic-related paracrine secretion of mMSCs (RANKL, M-CSF and OPG), despite its small effect on the osteogenesis of mMSCs. This secretory profile was found to be able to effectively inhibit osteoclastogenesis in RAW264.7 cells, confirming the enhanced osteoclastogenesis inhibitory functions of mMSCs on the osteon-like concentric microgrooved surface. Our findings demonstrate the importance of the microgroove orientation and arrangement in affecting cellular behaviors and highlight the potential benefits of incorporating osteon-like concentric microgrooved patterns on the surface of scaffolds for bone repair.
Topics: Animals; Biocompatible Materials; Cell Culture Techniques; Cell Line; Mesenchymal Stem Cells; Mice; Osteoclasts; Osteogenesis; RAW 264.7 Cells; Surface Properties
PubMed: 31247479
DOI: 10.1016/j.biomaterials.2019.119269 -
Materials Science & Engineering. C,... Apr 2021Biphasic calcium phosphate ceramics (BCPs) have been extensively used as a bone graft in dental clinics to reconstruct lost bone in the jaw and peri-implant hard tissue...
Biphasic calcium phosphate ceramics (BCPs) have been extensively used as a bone graft in dental clinics to reconstruct lost bone in the jaw and peri-implant hard tissue due to their good bone conduction and similar chemical structure to the teeth and bone. However, BCPs are not inherently osteoinductive and need additional modification and treatment to enhance their osteoinductivity. The present study aims to develop an innovative strategy to improve the osteoinductivity of BCPs using unique features of zeolitic imidazolate framework-8 (ZIF8). In this method, commercial BCPs (Osteon II) were pre-coated with a zeolitic imidazolate framework-8/polydopamine/polyethyleneimine (ZIF8/PDA/PEI) layer to form a uniform and compact thin film of ZIF8 on the surface of BCPs. The surface morphology and chemical structure of ZIF8 modified Osteon II (ZIF8-Osteon) were confirmed using various analytical techniques such as XRD, FTIR, SEM, and EDX. We evaluated the effect of ZIF8 coating on cell attachment, growth, and osteogenic differentiation of human adipose-derived mesenchymal stem cells (hADSCs). The results revealed that altering the surface chemistry and topography of Osteon II using ZIF8 can effectively promote cell attachment, proliferation, and bone regeneration in both in vitro and in vivo conditions. In conclusion, the method applied in this study is simple, low-cost, and time-efficient and can be used as a versatile approach for improving osteoinductivity and osteoconductivity of other types of alloplastic bone grafts.
Topics: Bone Regeneration; Calcium Phosphates; Cell Differentiation; Humans; Hydroxyapatites; Osteogenesis; Zeolites
PubMed: 33812600
DOI: 10.1016/j.msec.2021.111972 -
Annals of Diagnostic Pathology Oct 2022The aim of this study was to assess the clinicopathological features of florid cemento-osseous dysplasia (FCOD)-related osteonecrosis highlighting their...
OBJECTIVE
The aim of this study was to assess the clinicopathological features of florid cemento-osseous dysplasia (FCOD)-related osteonecrosis highlighting their histopathological aspects and bone structure.
METHODS
Twenty-two FCOD-related osteonecrosis cases were evaluated retrospectively. Osteonecrosis, osteomyelitis, bacterial colonization, bone resorption, reactive bone, osteon-like structure, lamellar bone, and basophilic lines were analyzed. Specific staining and fluorescence and polarized light microscopy analyses were also performed.
RESULTS
The mandible was more affected by FCOD-related osteonecrosis. There was a predominance of African-Brazilian women in the fifth and seventh decades of life. Osteomyelitis was present in 82 % of cases whereas bone resorption and bacterial colonization were present in 100 % of FCOD-related osteonecrosis cases. Thick basophilic lines were seen in all cases (100 %). Actinomycosis and osteoclasts were not often.
CONCLUSIONS
This study showed female adult preference, mandibular location, and some findings such as osteomyelitis, bone resorption, and bacterial colonization were histopathological features more frequent in FCOD-related osteonecrosis. In the absence of a close clinical and radiographic correlation, the morphology of the necrotized bone similar to cementum could help to recognize FCOD.
Topics: Adult; Bone Resorption; Female; Fibrous Dysplasia of Bone; Humans; Osteomyelitis; Osteonecrosis; Retrospective Studies
PubMed: 35868115
DOI: 10.1016/j.anndiagpath.2022.152009 -
Journal of the Mechanical Behavior of... Oct 2022Preclinical studies often require animal models for in vivo experiments. Particularly in dental research, pig species are extensively used due to their anatomical...
Preclinical studies often require animal models for in vivo experiments. Particularly in dental research, pig species are extensively used due to their anatomical similarity to humans. However, there is a considerable knowledge gap on the multiscale morphological and mechanical properties of the miniature pigs' jawbones, which is crucial for implant studies and a direct comparison to human tissue. In the present work, we demonstrate a multimodal framework to assess the jawbone quantity and quality for a minipig animal model that could be further extended to humans. Three minipig genotypes, commonly used in dental research, were examined: Yucatan, Göttingen, and Sinclair. Three animals per genotype were tested. Cortical bone samples were extracted from the premolar region of the mandible, opposite to the teeth growth. Global morphological, compositional, and mechanical properties were assessed using micro-computed tomography (micro-CT) together with Raman spectroscopy and nanoindentation measurements, averaged over the sample area. Local mineral-mechanical relationships were investigated with the site-matched Raman spectroscopy and micropillar compression tests. For this, a novel femtosecond laser ablation protocol was developed, allowing high-throughput micropillar fabrication and testing without exposure to high vacuum. At the global averaged sample level, bone relative mineralization demonstrated a significant difference between the genotypes, which was not observed from the complementary micro-CT measurements. Moreover, bone hardness measured by nanoindentation showed a positive trend with the relative mineralization. For all genotypes, significant differences between the relative mineralization and elastic properties were more pronounced within the osteonal regions of cortical bone. Site-matched micropillar compression and Raman spectroscopy highlighted the differences between the genotypes' yield stress and mineral to matrix ratios. The methods used at the global level (averaged over sample area) could be potentially correlated to the medical tools used to assess jawbone toughness and morphology in clinics. On the other hand, the local analysis methods can be applied to quantify compressive bone mechanical properties and their relationship to bone mineralization.
Topics: Animals; Cortical Bone; Humans; Jaw; Mandible; Swine; Swine, Miniature; X-Ray Microtomography
PubMed: 35947925
DOI: 10.1016/j.jmbbm.2022.105405