Trabecular Bone Structure Research Articles

Trabecular Bone Score (TBS) in Primary Hyperparathyroidism (PHPT): A Useful Tool?

Primary Hyperparathyroidism (PHPT) often leads to bone loss, even in its asymptomatic presentations. Trabecular Bone Score (TBS) is a method to assess the trabecular bone structure of the spine. This study aimed to evaluate TBS measurements combined with Dual X-ray Absorptiometry (DXA) values in the search for more accurate bone fragility risk assessment among PHPT patients. From 2017 to 2019, patients diagnosed with PHPT (n = 64), before surgery, were invited to participate in this study. Bone mineral density (BMD) by DXA at the lumbar spine, total hip, femoral neck, distal third radius, and TBS were determined in patients and controls (n = 63). The vertebral fracture was defined using the Genant method in vertebral images by DXA and vertebral fracture assessment (VFA). Patients and controls did not differ in age, sex, menopausal status, or body mass index (BMI). The PHPT patients presented significantly lower BMD values than the controls in all sites evaluated. The TBS measurements were also statistically lower in PHPT patients than controls (mean TBS PHPT = 1.233 vs TBS controls = 1.280, p = 0.044). Osteoporosis was observed in 50% of PHPT patients and 26.6% of controls (p = 0.02). However, lumbar spine T-Score < -2.5 was observed only in 21.8% of PHPT patients. Vertebral fractures were detected in nine individuals (14%) from the PHPT group and four (6.3%) in the controls (p = 0.24). The TBS area under the curve (AUC) was higher than DXA AUC in all sites, for vertebral fracture assessment. The TBS AUC was significant in the PHPT group (0.75, 95% CI 0.62 - 0.88, p = 0.02) and not significant in the DXA analysis. The ROC curve showed that TBS values < 1.187 are associated with a significantly higher risk of vertebral fracture among PHPT patients (p = 0.02). The TBS used as a complement to DXA measurements is a useful tool which may better assess fragility risk among PHPT patients.

A novel hydroxyapatite fiber material for the regeneration of critical-sized rabbit calvaria defects

Hydroxyapatite (HA) [Ca10 (PO4)6 (OH)2] has a high degree of chemical similarity with the mineral composition of animal bone. Hydroxyapatite fiber scaffold (HAF) is a biological material with a highly interconnected porous structure. We aimed to study the physical and biological characteristics of HAF and compare the osteogenic effects of HAF, natural osteogenic materials (NOM), and carbonate apatite (CO3Ap-DP) in the parietal defects of a rabbit's skull. X-ray analysis and histological assessment showed that HAF followed a trend of early initial osteogenesis and bone trabecular structure formation, especially at the cortical bone portion.Compared to the other two materials, HAF was more absorptive. Results indicated that HAF had the same osteoconductive and new bone formation properties as NOM and CO3Ap-DP. These findings will provide options for future material development and novel protocols for use in surgeries, ultimately leading to better patient outcomes.

Multi-scale mechanical and morphological characterisation of sintered porous magnesium-based scaffolds for bone regeneration in critical-sized defects

Magnesium (Mg) and its alloys are very promising degradable, osteoconductive and osteopromotive materials to be used as regenerative treatment for critical-sized bone defects. Under load-bearing conditions, Mg alloys must display sufficient morphological and mechanical resemblance to the native bone they are meant to replace to provide adequate support and enable initial bone bridging. In this study, unique highly open-porous Mg-based scaffolds were mechanically and morphologically characterised at different scales. In situ X-ray computed tomography (XCT) mechanics, digital volume correlation (DVC), electron microscopy and nanoindentation were combined to assess the influence of material properties on the apparent (macro) mechanics of the scaffold. The results showed that Mg exhibited a higher connected structure (38.4mm−3 and 6.2mm−3 for Mg and trabecular bone (Tb), respectively) and smaller spacing (245µm and 629µm for Mg and Tb, respectively) while keeping an overall appropriate porosity of 55% in the range of trabecular bone (30-80%). This fully connected and highly porous structure promoted lower local strain compared to the trabecular bone structure at material level (i.e. -22067 ± 8409µε and -40120 ± 18364µε at 6% compression for Mg and trabecular bone, respectively) and highly ductile mechanical behaviour at apparent level preventing premature scaffold failure. Furthermore, the Mg scaffolds exceeded the physiological strain of bone tissue generated in daily activities such as walking or running (500-2000µε) by one order of magnitude. The yield stress was also found to be close to trabecular bone (2.06MPa and 6.67MPa for Mg and Tb, respectively). Based on this evidence, the study highlights the overall biomechanical suitability of an innovative Mg-based scaffold design to be used as a treatment for bone critical-sized defects. Statement of significanceBone regeneration remains a challenging field of research where different materials and solutions are investigated. Among the variety of treatments, biodegradable magnesium-based implants represent a very promising possibility. The novelty of this study is based on the characterisation of innovative magnesium-based implants whose structure and manufacturing have been optimised to enable the preservation of mechanical integrity and resemble bone microarchitecture. It is also based on a multi-scale approach by coupling high-resolution X-ray computed tomography (XCT), with in situ mechanics, digital volume correlation (DVC) as well as nano-indentation and electron-based microscopy imaging to define how degradable porous Mg-based implants fulfil morphological and mechanical requirements to be used as critical bone defects regeneration treatment.

Trabecular bone structure in advanced chronic kidney disease: Comparison of bone biopsy assessment using microCT and histomorphometry

Trabecular bone structure in advanced chronic kidney disease: Comparison of bone biopsy assessment using microCT and histomorphometry

Super-resolution and learned perceptual loss allows high-resolution imaging of trabecular bone with clinical cone beam computed tomography

Purpose: It is well known that osteoarthritis (OA)-related bone remodeling modifies trabecular bone structure. Subtle bone changes can be detected using high-resolution micro-computed tomography (μCT). However, the current clinical cone-beam CT (CBCT) technology cannot achieve sufficient resolution and contrast to visualize the bone microarchitecture. Previously, deep learning has been proposed to enhance image quality in musculoskeletal imaging, however, most studies generate low-resolution images using downsampling.

In-vitro trabecular bone damage following mono- and bicortical mini implants anchorage in mini-implant assisted rapid palatal expansion (MARPE)

To assess in-vitro trabecular bone damage following mono- and bicortical mini-implant (MI) anchorage in mini-implant assisted rapid palatal expansion (MARPE). Sixteen self-drilling MI (four MARPE appliances) were distributed in two groups according to bone insertion (monocortical and bicortical) in bovine rib. The device was activated five times (0.5mm each). Trabecular bone damage was assessed using micro-CT scans made at baseline and after each activation by trabecular spacing parameter (Tb.Sp) (distance [mm] between the trabecular bone structure). These measurements were made in five different regions of interest (ROI) surrounding the screw (whole, superior, inferior, anterior and posterior). Two-way ANOVA with Tukey post-hoc analysis (α=0.05) was used to evaluate the effect of insertion type (monocortical vs. bicortical) and activation cycle (0-5) on trabecular damage. The time effect was evaluated using ANOVA-MR test effect with Bonferroni correction (α=0.003). The micro-CT images were also examined qualitatively. When analysing the individual ROIs, only the superior ROI had a significant difference (P<0.003) beginning at the fourth activation cycle. For the monocortical group, trabecular spacing was affected when the whole ROI was analysed beginning at the fourth activation cycle, while for the superior ROI, this difference became apparent beginning with the third activation cycle (P<0.003). For the qualitative analysis, it seems that only monocortical anchorage influences the trabecular bone in the superior area. Monocortical anchorage is more susceptible to bone damage around the MIs, with the superior (cervical) region most strongly affected.

Early ontogeny of humeral trabecular bone in Neandertals and recent modern humans

Trabecular bone ontogeny is well known in modern humans and unknown in Neandertals. Yet the bone developmental pattern is useful for interpreting fossils from evolutionary and functional perspectives. Interestingly, microstructure in early ontogeny is supposedly not influenced by high and specific mechanical loading related to the lifestyle of a human group and consequently does not directly depend on the activities of hunter-gatherers. Here, we specifically explored the early growth trajectories of the trabecular bone structure of the humerus and emphasized in particular how bone fraction (bone volume/total volume [BV/TV]) was built up in Neandertals, given the specific modern human bone loss after birth and the use of BV/TV in functional studies. Six Neandertals and 26 recent modern humans ranging from perinates to adolescents were included in this study. Six trabecular parameters were measured within a cubic region of interest extracted from the proximal metaphysis of the humerus. We found that the microstructural changes in Neandertals during early ontogeny (<1 year) fit with modern human growth trajectories for each parameter. The specific bone loss occurring immediately after birth in modern humans also occurred in Neandertals (but not in chimpanzees). However, the early childhood fossil Ferrassie 6 presented unexpectedly high BV/TV, whereas the high BV/TV in the Crouzade I adolescent was predictable. These results suggest that Neandertals and modern humans shared predetermined early growth trajectories and developmental mechanisms. We assume that the close relationship between skeletal characteristics in early ontogeny and adults in modern humans also existed in Neandertals. However, it was difficult to ensure that the high BV/TV in Neandertal early childhood, represented by only one individual, was at the origin of the high BV/TV observed in adults. Consequently, our study does not challenge the mechanical hypothesis that explains the trabecular gracilization of the humerus during the Holocene.

Microstructural and Strength Changes in Trabecular Bone in Elderly Patients with Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide and it is associated with an increased risk of osteoporosis and fragility fractures. Our aim is to analyze the effect of T2DM on bone quality. This is a case-control study. The studied population consisted of 140 patients: 54 subjects with hip fracture (OP) without T2DM, 36 patients with hip fracture and T2DM (OP-T2DM), 28 patients with osteoarthritis (OA) without T2DM, and 22 patients with OA and T2DM (OA-T2DM). Bone markers, bone mineral density, FRAX score, microstructural, and bone material strength from femoral heads were assessed. The group with hip fracture presented lower BMD values than OA (p < 0.05). The OP, OP-T2DM, and OA-T2DM groups showed a decrease in bone volume fraction (BV/TV), in trabecular number (Tb.N), and in trabecular thickness (Tb.Th), while an increase was presented in the structural model index (SMI) and trabecular bone pattern factor (Tb.Pf), The groups OP, OP-T2DM, and OA-T2DM also presented lower values than those in group OA regarding the biomechanical parameters in the form of Young’s modulus or elastic modulus, toughness, ultimate stress, ultimate load, extrinsic stiffness, and work to failure (p < 0.05). Our results show the negative effect of type 2 diabetes mellitus on trabecular bone structure and mechanical properties.

A New Additive-Manufactured Cementless Highly Porous Titanium Acetabular Cup for Primary Total Hip Arthroplasty-Early Two-Year Follow Up.

Additive-manufacturing technologies are increasingly being used, not only to create acetabular components with porous coating architecture very similar to the complex trabecular structure of cancellous bone, but also for producing the entire implant in a single step. The aim of this study is to assess two-year clinical and radiological outcomes of a new additive-manufactured cup in primary total hip arthroplasty (THA). We reviewed 266 primary THAs (254 patients) performed in our institution between December 2016 and December 2018 using a new highly porous titanium acetabulum shell fabricated via additive manufacturing. Clinical and functional outcomes were measured using SF/VR-12 and HOOS JR to determine patient satisfaction with surgery. Radiographs were assessed to determine the presence of migration, radiolucency, and loosening. Patients records were reviewed to assess cup survivorship in terms of all-cause revisions and revision for aseptic cup loosening. At a minimum of two-year follow up (range: 2-3.45 years), the patient cohort demonstrated significant improvement in postoperative functional scores (hip disability and osteoarthritis outcome score for joint replacement [HOOS JR.] and clinical scores (12-item short-form health survey [SF/VR-12]) (p<0.001). One cup developed progressive radiolucent lines at the prosthesis-bone interface consistent with loosening and was revised. The overall acetabular component two-year survivorship free of all-cause failure was 97.4% (95% confidence interval [CI]: 95.5-99.4%). When aseptic loosening of the acetabular component was used as the failure endpoint, the two-years survivorship rate was 99.6% (95% CI: 98.9-100%). Highly porous titanium cementless acetabular cups produced via additive-manufacturing showed promising early clinical and radiological results in primary THA with low rates of aseptic loosening. Further follow-up studies are needed to assess the long-term survivorship and outcomes of this new acetabular component.

Silencing Proteasome 26S Subunit ATPase 2 (PSMC2) Protects the Osteogenic Differentiation In Vitro and Osteogenesis In Vivo.

Osteoporosis is a commonly seen degenerative bone disorder in the elderly and postmenopausal women, with a low bone mineral density as a major risk factor. The osteogenic potential of bone marrow stromal cells (BMSCs) showed to be impaired during osteoporosis. We established a postmenopausal osteoporosis model in ovariectomized (OVX) mice and found the upregulation of proteasome 26S subunit ATPase 2 (PSMC2) in OVX mice. PSMC2 silencing improved OVX-impaired biomechanical properties of mice femur, OVX-decreased BMD, and OVX-destroyed bone structure. Histopathological analysis indicated that PSMC2 silencing improved bone trabecular structure and increased the contents of collagen fibers and newly formed bone or cartilage in OVX mice. In the meantime, PSMC2 silencing increased Runx2, PI3K, Wnt3a, and β-catenin protein contents while reduced CTSK protein. Within BMSCs isolated from OVX mice, PSMC2 silencing promoted BMSC osteogenic differentiation and elevated osteogenic markers' protein contents, including HOXA10, Runx2, OCN, OPN, and COL1A2. In conclusion, PSMC2 expression is upregulated in the postmenopausal osteoporosis model in OVX mice. PSMC2 silencing promotes the osteogenic differentiation of BMSCs in vitro, promotes bone formation, and inhibits bone resorption in vivo.

Evaluation of La(XT), a novel lanthanide compound, in an OVX rat model of osteoporosis

PurposeThe purpose of this study was to evaluate the efficacy and toxicity of a novel lanthanum compound, La(XT), in an ovariectomized (OVX) rat model of osteoporosis. MethodsTwenty-four ovariectomized female Sprague Dawley rats were divided into 3 groups receiving a research diet with/without treatment compounds (alendronate: 3 mg/kg; La(XT) 100 mg/kg) for three months. At the time of sacrifice, the kidney, liver, brain, lung and spleen were collected for histological examination. The trabecular bone structure of the tibiae was evaluated using micro-CT and a three-point metaphyseal mechanical test was used to evaluate bone failure load and stiffness. ResultsNo significant differences were noted in plasma levels of calcium, phosphorus, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) between the La(XT) treatment compared to the non-treated OVX group. Alendronate-treated animals (positive control) showed higher BV/TV, Tb.N and lower Tb.Th and Tb.Sp when compared to the non-treated OVX group. Mechanical analysis indicated that stiffness was higher in the alendronate (32.88%, p = 0.04) when compared to the non-treated OVX group. Failure load did not differ among the groups. ConclusionsNo kidney or liver toxicities of La(XT) treatments were found during the three-month study. The absence of liver and kidney toxicity with drug treatment for 3 months, as well as the increased trabecular bone stiffness are encouraging for the pursuit of further studies with La(XT) for a longer duration of time.

Fluid-structure interaction (FSI) modeling of bone marrow through trabecular bone structure under compression.

The present study has sought to investigate the fluid characteristic and mechanical properties of trabecular bone using fluid-structure interaction (FSI) approach under different trabecular bone orientations. This method imposed on trabecular bone structure at both longitudinal and transverse orientations to identify effects on shear stress, permeability, stiffness and stress regarded to the trabeculae. Sixteen FSI models were performed on different range trabecular cubes of 27mm3 with eight models developed for each longitudinal and transverse direction. Results show that there was a moderate correlation between permeability and porosity, and surface area in the longitudinal and transverse orientations. For the longitudinal orientation, the permeability values varied between 3.66 × 10-8 and 1.9 × 10-7 and the sheer stress values varied between 0.05 and 1.8Pa, whilst for the transverse orientation, the permeability values varied between 5.95 × 10-10 and 1.78 × 10-8 and the shear stress values varied between 0.04 and 3.1Pa. Here, transverse orientation limits the fluid flow from passing through the trabeculae due to high shear stress disturbance generated within the trabecular bone region. Compared to physiological loading direction (longitudinal orientation), permeability is higher within the range known to trigger a response in bone cells. Additionally, shear stresses also increase with bone surface area. This study suggests the shear stress within bone marrow in real trabecular architecture could provide the mechanical signal to marrow cells that leads to bone anabolism and can depend on trabecular orientation.

Trabecular and cortical bone are unaltered in response to chronic lipopolysaccharide exposure via osmotic pumps in male and female CD-1 mice.

Chronic low-grade inflammation has been identified as an underlying cause of many diseases including osteoporosis. Lipopolysaccharide (LPS) is a potent inducer of the inflammatory response that can negatively affect bone outcomes by upregulating bone resorption and inhibiting bone formation. The objective of this study was to assess the longitudinal response of trabecular and cortical bone structure and bone mineral density to LPS continuously administered for 12 weeks in male and female CD-1 mice. Mice were assigned to one of four LPS groups at 8-weeks of age: placebo (0.0 μg/d), low (0.9 μg/d), mid (3.6 μg/d) and high (14.4 μg/d) dose. Trabecular and cortical bone outcomes were measured at 8, 12, 16, and 20 weeks of age using in vivo micro-computed tomography. The anticipated serum LPS dose-dependent response was not observed. Therefore, the low, mid, and high LPS groups were combined for analysis. Compared to the placebo group, endpoint serum LPS was elevated in both males (p < 0.05) and females (p < 0.05) when all LPS treatment groups were combined. However, there was no significant change in trabecular or cortical bone outcomes in the combined LPS groups compared to the placebo following the 12-week LPS intervention for either sex. This suggests that although serum LPS was elevated following the 12-week LPS intervention, the dosages administered using the osmotic pumps was not sufficient to negatively impact trabecular or cortical bone outcomes in either male or female CD-1 mice.

Selective Voronoi tessellation as a method to design anisotropic and biomimetic implants

The geometry of a metallic scaffold is important for the success of bone implants, where the introduction of porosity can reduce stress shielding effects and allow for bone tissue integration. In this work, porous scaffolds were designed to closely mimic the natural structure of trabecular bone using selective Voronoi tessellation with preferential seeding. A workflow to generate these structures is introduced, where voided regions of seeds in the starting volume create preferential texture during polyhedral expansion, resulting in modified strut orientation in the implant. Anisotropy was digitally characterized by mean-intercept length and star volume distribution measurements to determine similarity to trabecular orientation. This work demonstrates that selective Voronoi tessellation is an effective method to generate biomimetic porous scaffolds with increased anisotropy and tunable strut architecture in three dimensions as a suitable alternative to patient-derived bone geometries.

Bone and muscle development in three inbred female mouse strains

ABSTRACTMuscle force is thought to be one of the main determinants of bone development. Hence, peak muscle growth is expected to precede peak bone growth. In this study, we investigated muscle and bone development in female C57BL/6 J, DBA/2JRj, and C3H/HeOuJ mice. Femoral cortical and trabecular bone structure and the weights of selected muscles were assessed at the ages of 8, 16, and 24 weeks. Muscle mass increased from 8 to 24 weeks in all 3 strains, suggesting peak muscle development at 24 weeks or later. Bone volume fraction, trabecular number, and connectivity density of the femur decreased or remained unchanged, whereas trabecular density and trabecular thickness largely increased. These results suggest a peak in trabecular bone accrual at 8 weeks or earlier followed by further increases in density and structural reorganization of trabeculae. Cortical density, cortical thickness, and cortical cross sectional area increased over time, suggesting a peak in cortical bone accrual at 24 weeks or later. In conclusion, our data provide evidence that growth of muscle lags behind trabecular bone accrual.

Investigation of mandibular fractal dimension on digital panoramic radiographs in bruxist individuals

This study aimed to evaluate changes in mandibular trabecular bone structure in bruxism using fractal analysis on digital panoramic radiographs obtained with automatic dosing. In this prospective study, fractal analysis was performed on radiographs of 126 bruxists and 126 non-bruxists. Eight paired mandibular regions of interest were selected: the bilateral condylar and gonial regions, and the bilateral dentate regions between the apical areas of the first molar and second premolar and between the first premolar and canine. Fractal dimensions (FDs) were calculated at each site. Mean FD values in the bilateral gonial regions of the bruxists were significantly lower than those of controls (P ≤ .049). In both groups, FD values of the right dentate region anterior to the mental foramen were significantly lower than those on the left side (P ≤ .042). Females exhibited significantly lower FD values in both condylar regions in both groups (P ≤ .039) and in the right dentate regions in the controls (P ≤ .022). Correlations between age and FD in all regions were positive but nonsignificant in both groups (P > .05). FD values of mandibular trabecular bone are affected by bruxism in the gonial region and by laterality and sex differences in the condylar and dentate regions.

Reproducibility of Replicated Trabecular Bone Structures from Ti6Al4V Extralow Interstitials Powder by Selective Laser Melting

Reproducibility of Replicated Trabecular Bone Structures from Ti6Al4V Extralow Interstitials Powder by Selective Laser Melting

THE EFFECT OF ADIPONECTIN VIA REGULATING THE BONE MICROENVIRONMENT OXIDATIVE STRESS ON OSTEOGENESIS IN TYPE 2 DIABETIC RATS.

To observe the effect of adiponectin on osteogenesis in type 2 diabetic rats. The 4th-week-old male SD rats were divided into normal control group (n=18) and diabetic model group (n = 42). Type 2 diabetes was induced by high-fat and high-sugar diet and intraperitoneal injection of a low dose of streptozotocin (STZ). The successfully-induced diabetic rats were divided into diabetic group (DM=18) and adiponectin intervention group (APN=18). APN group was injected with APN 10 μg/kg*d. The rats were separately sacrificed at the 4th, 8th and 12th week after the intervention. Bone microstructure and adipose tissue were observed via HE staining. Bone marrow was extracted from one side of the femur, and the supernatant was achieved by centrifugation. After BMD assessed by DXA, the other side of the femur was for further HE staining. Runx-2 expression in the bone marrow cells was detected by RT-PCR. BALP and AOPPs in bone marrow supernatant were assayed by ELISA. AGEs were detected by immunohistochemical staining. With the feeding time over, blood glucose, AOPP, and AGEs were increased, and Runx-2 mRNA, BALP, BMD were decreased in diabetic rat group(P<0.05). Oxidative stress (OS) maker (AOPP) was decreased and osteogenesis makers (Runx2 mRNA, BALP) were increased after intervention with exogenous adiponectin (P<0.05). At the 8th and 12th week, the trabecular bone became thinner and broken, and the fat cell number increased in all 3 groups, especially in the DM group. The adiponectin intervention group showed that the trabecular bone structure was moderately restored. OS is obvious in bone micro-environment in diabetic rats. OS may have an inhibitory effect on regulation of osteogenic differentiation factor Runx2, causing down regulation of osteoblast differentiation and bone formation. Adiponectin may improve OS response and protect the bone structure.

GATA4-driven miR-206-3p signatures control orofacial bone development by regulating osteogenic and osteoclastic activity.

Growth disorders in the orofacial bone development process may lead to orofacial deformities. The balance between bone matrix formation by mesenchymal lineage osteoblasts and bone resorption by osteoclasts is vital for orofacial bone development. Although the mechanisms of orofacial mesenchymal stem cells (OMSCs) in orofacial bone development have been studied intensively, the communication between OMSCs and osteoclasts remains largely unclear.Methods: We used a neural crest cell-specific knockout mouse model to investigate orofacial bone development in GATA-binding protein 4 (GATA4) morphants. We investigated the underlying mechanisms of OMSCs-derived exosomes (OMExos) on osteoclastogenesis and bone resorption activity in vitro. miRNAs were extracted from OMExos, and differences in miRNA abundances were determined using an Affymetrix miRNA array. Luciferase reporter assays were used to validate the binding between GATA4 and miR-206-3p in OMSCs and to confirm the putative binding of miR-206-3p and its target genes in OMSCs and osteoclasts. The regulatory mechanism of the GATA4-miR-206-3p axis in OMSC osteogenic differentiation and osteoclastogenesis was examined in vitro and in vivo.Results: Wnt1-Cre;Gata4fl/fl mice (cKO) not only presented inhibited bone formation but also showed active bone resorption. Osteoclasts cocultured in vitro with cKO OMSCs presented an increased capacity for osteoclastogenesis, which was exosome-dependent. Affymetrix miRNA array analysis showed that miR-206-3p was downregulated in exosomes from shGATA4 OMSCs. Moreover, the transcriptional activity of miR-206-3p was directly regulated by GATA4 in OMSCs. We further demonstrated that miR-206-3p played a key role in the regulation of orofacial bone development by directly targeting bone morphogenetic protein-3 (Bmp3) and nuclear factor of activated T -cells, cytoplasmic 1 (NFATc1). OMExos and agomiR-206-3p enhanced bone mass in Wnt1-cre;Gata4fl/flmice by augmenting trabecular bone structure and decreasing osteoclast numbers.Conclusion: Our findings confirm that miR-206-3p is an important downstream factor of GATA4 that regulates the functions of OMSCs and osteoclasts. These results demonstrate the efficiency of OMExos and microRNA agomirs in promoting bone regeneration, which provide an ideal therapeutic tool for orofacial bone deformities in the future.

Topological Design of a Trabecular Bone Structure With Morphology and Mechanics Control for Additive Manufacturing

Porous metals are found to be suitable as orthopedic scaffolds. However, only limited control over the internal architecture can be achieved using conventional design methods. The architecture with porosity variation strategy mimicking natural bone is critical to gain favorable combination of mechanical and biological properties for orthopedic implants. In this regard, a topology optimization method with customized morphology and mechanical properties derived from the trabecular bone was proposed to design three-dimensional architectures with gradient porosity resembling the porous structure of bone. In particular, the elastic constants for the trabecular bone were better predicted when the bone volume fraction was supplemented with a three-dimensional structural parameter, i.e., degree of anisotropy. These constants were set as the optimization constrains for morphology control. Then the porous titanium structures were manufactured by selective laser melting technology (SLM). The physical characteristics, mechanical properties of the scaffolds were compared systematically. The experimental results revealed that the as-built samples with the proposed method lead to a good match of morphological accuracy and mechanical properties to that of the bone. It demonstrates that the proposed topology optimization method with controlled morphology and mechanical properties provides an efficient manner for the biomimetic design of orthopedic implants.