Bone Structure Research Articles

Evaluation of fractal analysis and radiomorphometric measurements of mandibular bone structure in bruxism and non-bruxism paediatric patients.

The goal of this examination was to compare the impact of probable sleep/awake bruxism on the mandibular trabecular bone structure by fractal analysis (FA) with digital panoramic radiograph (DPR) and radiomorphometric measurements in paediatric patients with bruxism. The examination included 130 participants with 63 patients with probable sleep/awake bruxism and 67 control groups. Bilateral regions of interest (ROI) in three regions were examined as ROI1: mandibular ramus, ROI2: mandibular angulus, ROI3: anterior to the molar teeth. Radiomorphometric measurements were taken of the mandibular cortical width (MCW), panoramic mandibular index (PMI), and mandibular cortical index (MCI). p < 0.05 was approved for statistical significance. The ROI-1, ROI-2, and ROI-3 values were defined to be statistically significantly high in the bruxism group (p < 0.05). No significant difference was found between the groups in the other values (p > 0.05). There was no difference in the age and gender for any of the parameters (p > 0.05). In children and adolescents, the mandibular trabecular bone can be affected by bruxism. FA can be used as an auxiliary method for finding the mandibular trabecular differences of patients with bruxism in paediatric dentistry just as it can for adults.

Can intra-articular daidzein injection reduce oxidative damage and early osteoarthritis in a rabbit temporomandibular joint model?

BackgroundOxidative damage and inflammatory cytokines in osteoarthritis (OA) exacerbate the disease course. Daidzein (DZ) has antioxidant and anti-inflammatory effects. This study evaluated the early histopathological effects of intra-articular daidzein injection on experimentally induced osteoarthritis in rabbit TMJs.MethodsThe predictor variable was intra-articular injection of DZ or a saline control. 50 µl of 3 mg/mL MIA solution was injected into the right TMJ of 16 New Zealand rabbits to induce experimental OA. One rabbit was sacrificed after 4 weeks to confirm the formation of the OA model and the OA model was obtained. The remaining 15 rabbits were randomly divided into 2 groups: an experimental group (9 rabbits) and a control group (6 rabbits). On days 1, 7, 14, and 21; 50 µl of saline solution was applied to the right TMJ of the control group and 50 µl daidzein solution (1.8 mg/ml) was applied to the right TMJ to the experimental group. After one week from the date of the last injection, the rabbits were sacrificed, and histopathological and biochemical evaluations were performed. The Shapiro-Wilk test was used to evaluate whether the variables in the study conformed to normal distribution. Mean ± SD (standard deviation) or median (interquartile range (IQR)) was used to show the descriptive statistics of the variables. T-test and Mann Whitney U test were used to compare the control and experimental groups for biochemical changes. The chi-square test was used to show the distribution of histopathological changes variables obtained within the scope of the study based on control and experimental groups. A P-value < 0.05 was considered significant for all evaluations.ResultsThere were 8 and 6 animate treated with DZ and saline, respectively. There was no statistically significant difference between groups in articular cartilage (p = 0.3), osteochondral junction (p = 0.3), subchondral bone structure (p = 1.0) or chondrocyte appearance (p = 0.4). The experimental group showed significantly lower mean values for Total Oxidant Status (TOS) (p = 0.002) and Oxidative Stress Index (OSI) (p = 0.007).ConclusionsAn intra-articular DZ injection appears to show limited reduction of oxidative damage and early OA in the rabbit TMJ. DZ might represent a promising natural compound with beneficial effects in the management of TMJ-OA.

Synthesis and Characterization of Ti-13Ta-6Sn Foams Produced Using Mechanical Alloying, the Space Holder Method and Plasma-Assisted Sintering

Highly porous titanium foams are great candidates for replacing bone structures with a low elastic modulus owing to their ability to avoid the stress shielding effect. However, the production of highly porous foams (&gt;70 vol.%) with well-distributed, stable, and predictable porous architectures using powder compaction and space holders is challenging. In this study, pure titanium powder and mechanically alloyed Ti-13Ta-6Sn were mixed with 50, 70, and 80 vol.% KCl powders as a space holder, cold-compacted, and sintered in a plasma-assisted sintering reactor to produce highly porous foams. The space holder was completely removed using heat and plasma species collisions prior to sintering. A Ti-13Ta-6Sn alloy powder with α, β, and metastable FCC-γ phases was synthesized. The characteristics of the alloyed powder, mixing step, and the resulting sintered samples were compared to those of CP-Ti. After sintering, the alloy exhibited α and β phases and a reduced elastic modulus. Foams with an elastic modulus in the range of the cortical and trabecular bones were obtained. The results showed the effects of the space holder volume fractions on the volume fraction, size, distribution, interconnectivity, and shape of the pores. The Ti-13Ta-6Sn foams exhibited a uniform open-celled porous architecture, lower elastic modulus, higher yield strength, and higher passivation resistance than CP-Ti. Ti-13Ta-6Sn exhibited a nontoxic effect for the mouse fibroblast cell line.

Total body irradiation is associated with long-term deficits in femoral bone structure but not mechanical properties in male rhesus macaques.

Exposure to ionizing radiation for oncological therapy increases the risk for late-onset fractures in survivors. However, the effects of total body irradiation (TBI) on adult bone are not well-characterized. The primary aim of this study was to quantify the long-term effects of TBI on bone microstructure, material composition, and mechanical behavior in skeletally mature rhesus macaque (Macaca mulatta) non-human primates. Femora were obtained post-mortem from animals exposed to an acute dose of TBI (6.0-6.75Gy) nearly a decade earlier, age-matched non-irradiated controls, and non-irradiated young animals. The microstructure of femoral trabecular and cortical bone was assessed via micro-computed tomography. Material composition was evaluated by measuring total fluorescent advanced glycation end products (fAGEs). Cortical bone mechanical behavior was quantified via four-point bending and cyclic reference point indentation (cRPI). Animals exposed to TBI had slightly worse cortical microstructure, including lower cortical thickness (-11%, p = 0.037) and cortical area (-24%, p = 0.049), but similar fAGE content and mechanical properties as age-matched controls. Aging did not influence cortical microstructure, fAGE content, or cRPI measures but diminished femoral cortical post-yield properties, including toughness to fracture (-32%, p = 0.032). Because TBI was administered after the acquisition of peak bone mass, these results suggest that the skeletons of long-term survivors of adulthood TBI may be resilient, retaining or recovering their mechanical integrity during the post-treatment period, despite radiation-induced architectural deficits. Further investigation is necessary to better understand radiation-induced skeletal fragility in mature and immature bone to improve care for radiation patients of all ages.

Comparative Histological Analysis of Dentine-Derived Tooth Grafts in Maxillary vs Mandibular Socket Preservation: A Retrospective Study of 178 Cases.

(1) Background: In recent years, there has been a growing interest in tooth-derived materials as valuable alternatives to synthetic biomaterials for preventing alveolar ridge dimensional changes. This study aimed to evaluate the histological and clinical differences between alveolar ridge preservation procedures in the maxilla and mandible using demineralized dentin treated with Tooth Transformer®. (2) Methods: A total of 178 patients in good general health were enrolled, with 187 post-extractive sockets lacking buccal and/or palatal bone walls. Alveolar socket preservation procedures and histological evaluations were performed. The sites were divided into two groups: Group A (99 mandibular samples) and Group B (108 maxillary samples). After 5 months (±1 month), single bone biopsies were performed for histologic and histomorphometric analysis. (3) Results: Clinical outcomes demonstrated a good healing of hard and soft tissues with an effective maintenance of bone architecture in both groups. Histomorphometric analysis revealed a total bone volume of 50.33% (±14.86) in Group A compared to 43.53% (±12.73) in Group B. The vital new bone volume was 40.59% (±19.90) in Group A versus 29.70% (±17.68) in Group B, with residual graft dentin material volume at 7.95% (±9.85) in Group A compared to 6.75% (±9.62) in Group B. (4) Conclusions: These results indicate that tooth-derived material supports hard tissue reconstruction by following the structure of the surrounding bone tissue. A 6.8% difference observed between the maxilla and mandible reflects the inherent disparities in natural bone structures in these regions. This suggests that the bone regeneration process after tooth extraction adheres to an anatomical functional pattern that reflects the specific bone characteristics of each area, thus contributing to the preservation of the morphology and functionality of the surrounding bone tissue.

5120 Contribution Of Proximal Femur Geometry And Bone Density Distribution To Hip Fragility In Adults ≥ 50yrs With Longstanding Type 1 Diabetes

Abstract Disclosure: F. Johannesdottir: None. C. D’Mello: None. A.B. Murthy: None. B. Zahedi: None. K. Engelke: None. M.L. Bouxsein: None. E.W. Yu: Grant Recipient; Self; Amgen Inc. Introduction: Adults with type 1 diabetes (T1D) have a 6-fold increased risk of hip fracture, which is explained only in part by lower areal bone mineral density (aBMD) by DXA. We hypothesize that femoral geometry and regional bone deficits at the proximal femur contribute to higher hip fracture risk in older adults with T1D. Further, we determine the influence of age at T1D diagnosis on femoral bone density and structure. Methods: We enrolled 97 individuals with T1D and 53 non-diabetic controls (CON) as part of the T1D Bone Health Connection (BEACON) Study, an ongoing prospective study of adults aged ≥50 years. We obtained computed tomography (CT) scans of the proximal femur (in-plane pixel size 0.98x0.98 mm, 1.25 mm slice thickness) to measure total (Tt), trabecular (Tb) and cortical (Ct) volumetric BMD (vBMD); and volume (Vol) and Ct thickness (Th) in several regions, including total hip, femoral neck (FN), trochanter (TR) and intertrochanter (IT) (Medical Image Analysis Framework, University of Erlangen, Germany). We also assessed total hip and FN aBMD by DXA. We employed ANCOVA models to compare bone outcomes between T1D and controls with adjustment for age, height, and weight, stratified by sex. When comparing bone outcomes within T1D, we adjusted for age, height, weight, and sex. Differences are reported as % difference between the least-square means for the groups. Results: The average age of participants was 64±7 yrs, and similar between T1D and CON (p=0.21). Male T1D were shorter than male CON (173 cm vs 176 cm, p=0.05), but with similar weight (p=0.73). Female T1D were heavier than female CON (71 kg vs 64 kg, p=0.03). The T1D cohort included 50 men and 47 women with mean diabetes duration of 46±10 yrs, mean A1c 7.1±1.0%, and median age at onset 17 yrs (IQR:10-25). Among T1D, 31 (52% female) were diagnosed ≤ age 12. Among men, total hip and FN aBMD did not differ by group, but T1D had smaller FN Tt.Vol (9%) and FN width (8%) (p&amp;lt;0.05 for all). In contrast, there were no differences between T1D and CON in the female cohort, neither by DXA nor CT (p≥0.13). Of note, T1D men appeared to have more poorly controlled diabetes than women (29% of men vs 11% women had A1c ≥8%, p=0.03). Within T1D, those who were diagnosed ≤ age 12 had lower Tb.vBMD (16-18%) at the total hip, TR and IT regions (p&amp;lt;0.05) and tended to have lower Tb.vBMD (16%, p=0.06) at the neck compared to those diagnosed at a later age, but no differences in DXA aBMD (p&amp;gt;0.31). Conclusion: In sum, older men, but not women, with T1D showed some deficits in bone structure at the proximal femur. Adults with T1D who were diagnosed ≤ age 12 had trabecular bone deficits within the proximal femur. Additional studies are needed to identify mechanisms underlying the high hip fracture risk in T1D. Presentation: 6/1/2024

7140 Assessing Bone Mineral Density and Cortical Geometry Using High-resolution Peripheral Quantitative Computed Tomography and Dual Energy X-ray Absorptiometry in Pediatric Survivors of High-risk Neuroblastoma with Growth Failure

Abstract Disclosure: S. Gera: None. M. Guo: None. N. Pollock: None. I. Hampton: None. M. Song: None. D. Weber: None. M. Denburg: None. S. Mostoufi-Moab: None. Introduction: Survival of children with high-risk neuroblastoma (HR-NBL) has increased with multimodal therapy. Cis-retinoic acid (cis-RA), cornerstone of HR-NBL therapy, can cause osteoporosis and premature physeal closure, posing a threat to skeletal structure. HR-NBL survivors demonstrate profound growth failure. DXA measures areal bone mineral density (aBMD). DXA is confounded by short stature and fails to distinguish between trabecular and cortical bone. We previously reported no significant difference in height-per-age adjusted aBMD-Z in HR-NBL survivors compared to healthy controls[1]. However, aBMD-Z in severe short stature may attenuate bone density deficits. High-resolution peripheral quantitative computed tomography (HRpQCT) yields 3D measures of volumetric BMD and bone architecture. Objectives: Assess volumetric BMD (vBMD) and cortical structure using distal tibia HRpQCT and leg lean mass by DXA in HR-NBL survivors compared to healthy controls in a cross-sectional study. Methods: We prospectively enrolled 20 HR-NBL survivors (median age 12.2 yrs, range 9.5 to 15.8, 7 female) treated with cis-RA (median age 2.6 yrs at start of therapy, range 0.3-9.1), and 20 age-, sex-, and race-matched healthy controls. We assessed leg lean mass adjusted for leg length by DXA. For HRpQCT, we compared tibia length (cm), cortical and trabecular vBMD (mg HA/cm3), geometry parameters (cortical and trabecular area [mm2]), and structural parameters (cortical thickness [μm] and porosity, trabecular number [mm-[1]] and separation [μm]). Outcomes were compared using Student’s t-test or Mann-Whitney U test. Linear regression models assessed difference in outcomes of bone microarchitecture and leg lean mass between both groups. Results: Compared to controls, tibia length was significantly shorter in HR-NBL survivors (32.3 ± 0.8 vs. 35.7 ± 0.6, P&amp;lt;0.005). HR-NBL survivors demonstrated lower cortical area (187.6 ± 43.8 vs. 218.7 ± 42.3, P&amp;lt;0.05), cortical perimeter (62.4 ± 7.71 vs. 69.5 ± 8.1, P&amp;lt;0.01), and leg lean mass Z-score (-1.47 ± 1.34 vs. -0.20 ± 0.84, P&amp;lt;0.001) compared to controls. Cortical geometry deficits were explained by muscle deficits (P&amp;lt;0.001). Trabecular area, BMC, areal and volumetric BMD, and measures of bone structure were not significantly different in HR-NBL survivors compared to controls. IGF-1 and 25-OH D levels had no significant effects on DXA or HRpQCT parameters. Conclusion: Bone density is not severely impacted in HR-NBL survivors. Muscle deficits persist years after treatment and explain cortical geometry deficits. HRpQCT substantiates prior DXA evaluation in HR-NBL survivors with significant short stature, demonstrating preserved bone density and structure. 1.Guo et al. Sarcopenia and preserved bone mineral density in pediatric survivors of high-risk neuroblastoma with growth failure. J Cachexia Sarcopenia Muscle. 2021 Aug;12(4):1024-1033. Presentation: 6/3/2024

7850 Developmental ZNHIT3 expression in mice embryos in Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome related organs

Abstract Disclosure: D. Kira: None. B. Eroglu, MS, PhD: None. Z. Hawkins: None. L.P. Chorich: None. S. Brakta: None. L.C. Layman: None. Introduction: MRKH is a severe form of the Mullerian duct (MD) anomaly where the upper 2/3 of the vagina and the uterus fail to develop. Individuals with MRKH still have normally functioning ovaries and normal chromosomes. MRKH may be isolated Mullerian aplasia (type 1) or associated with renal, skeletal, cardiac, and/or auditory dysfunction (type 2). The etiology of MRKH syndrome remains unknown for most probands, although a genetic contribution is likely. Most evidence suggests autosomal dominant inheritance with incomplete penetrance. WNT4 and HNF1B pathogenic variants have been identified in some MRKH individuals. Recently, our lab identified heterozygous (HTZ) ZNHIT3 loss of function variants in persons with MRKH, Both variants predict functional changes in the ZNHIT3 C-terminus and impair protein expression in vitro. Previously, other investigators found biallelic variants in the N-terminus of ZNHIT3 in individuals with PEHO syndrome, a severe autosomal recessive neurodevelopmental disorder characterized by extreme cerebellar atrophy. We are currently characterizing a novel Znhit3 knockout (KO) mouse model, in which homozygous KO mice exhibit embryonic lethality. We have demonstrated ZNHIT3 RNA expression in the human uterus, heart, kidney, and skeleton, but developmental expression of ZNHIT3 in wild type (WT) animals has not been studied. In the WT mouse embryo, the kidney forms between E8.0 and E11, while the MDs form through invagination of epithelium ∼E11.5 and extend along the Wolffian duct until reaching the cloaca at ∼E13.5. Hypothesis: We hypothesize that ZNHIT3 is involved in MD development and expressed in the urogenital system and MRKH-related organs during embryonic development of WT mice. Method: Timed mating of WT mice produced embryos for analysis. Embryos were dissected out at E11.5, 12.5 and 13.5, fixed in 4% PFA, embedded in paraffin, and sectioned sagittally at 5mm thickness. H&amp;E staining was done to identify sections showing kidney, genital tubercle, skeleton and cerebellum. Immunohistochemistry was also done using a ZNHIT3 antirabbit antibody and DAPI as nuclear counter stain. Imaging was performed using the Keyence fluorescence microscope (BZ-X800) at 10x and 40x magnification. Results: At all 3 time points, ZNHIT3 protein expression was observed in the developing urogenital organs including kidneys and bipotential gonads, as well as in vertebral bones and cerebellum. Heart protein expression studies are ongoing. Conclusion: ZNHIT3 protein expression is seen as early as E11.5 and is present in MRKH-related organs, suggesting it may play a role in the development of urogenital and MRKH-related organs. These findings provide the basis to compare expression in the Znhit3 KO mouse, a mouse model for MRKH. Presentation: 6/2/2024

Aerobic exercise training-induced bone and vascular adaptations in mice lacking adiponectin

Adiponectin regulates lipid and glucose metabolism, and insulin sensitivity in various target organs; however, the effects of adiponectin on bone health remain controversial. Exercise training can enhance bone density, bone microarchitecture, and blood flow. This study aimed to elucidate the role of adiponectin in adaptations of bone microarchitecture and bone vasculature in response to aerobic exercise training.Adult male C57BL/6 wild-type (WT) and homozygous adiponectin knockout (AdipoKO) mice were either treadmill exercise trained or remained sedentary for 8–10 weeks. The trabecular structures of the distal femoral metaphysis, a weight-bearing bone, and the mandible, a non-weight-bearing bone, were examined using microcomputed tomography. The femoral principal nutrient arteries were isolated to assess vasoreactivity (vasodilation and vasoconstriction) and structural remodeling.At the femoral metaphysis, impaired trabecular bone structures, including reduced connectivity density and increased trabecular spacing, were observed in AdipoKO mice compared to WT mice. In addition, nitric oxide-mediated, endothelium-dependent vasodilation was substantially reduced, and wall-to-lumen ratio was significantly increased in the femoral principal nutrient artery of AdipoKO mice. Interestingly, although exercise training-induced enhancements in trabecular connectivity density were observed at the femoral metaphysis of both WT and AdipoKO, increased vasoconstrictor responses were only observed in the femoral principal nutrient artery of WT mice, not in the AdipoKO mice. In mandibular trabecular bone, exercise training increased trabecular bone volume fraction (BV/TV, %) and intersection surface in the mandible of both WT and AdipoKO mice.These findings indicate that adiponectin is crucial for maintaining normal bone microarchitecture and vasculature. Although the absence of adiponectin compromises bone vascular adaptation to exercise training in mice, some exercise training-induced alterations in bone microarchitecture occurred in the absence of adiponectin, suggesting contribution of compensatory mechanisms during exercise training.

Bones or Stones: How Can We Apply Geophysical Techniques in Bone Research?

Some studies have used physical techniques for the assessment of bone structure and composition. However, very few studies applied multiple techniques, such as those described below, at the same time. The aim of our study was to determine the chemical and mineralogical/organic composition of bovine tibial bone samples using geophysical/geochemical reference techniques. X-ray diffraction (XRD), thermogravimetry (TG), Fourier-transform infrared spectrometry with attenuated total reflectance accessory (FTIR-ATR), inductively coupled mass spectrometry (ICP-MS) and inductively coupled optical emission spectrometry (ICP-OES) were applied to measure the organic and inorganic composition of 14 bovine bone samples. In addition, peripheral quantitative CT (QCT) was used to assess BMD in these bones. We were able to define the total composition of the studied bone samples. ICP-OES and ICP-MS techniques were used to determine the major and trace element composition. The X-ray analysis could detect inorganic crystalline compounds of bones, such as bioapatite, and its degree of ordering, indicating whether the bones belong to a younger or older individual. The total volatile content of the samples was calculated using TG and resulted in about 35 weight% (wt%). This, together with the 65 wt% total resulting from the chemical analysis (i.e., inorganic components), yielded a total approaching 100 wt%. As a large portion of the volatile content (H2O, CO2, etc.) was liberated from the organic components and, subordinately, from bioapatite, it could be concluded that the volatile-to-solid ratio of the examined bone samples was ~35:65. The FTIR-ATR analysis revealed that the organic portion consists of collagens containing amide groups, as their typical bands (OH, CH, CO, NC) were clearly identified in the infrared spectra. Numerous parameters of bone composition correlated with BMD as determined by QCT. In conclusion, we performed a complex evaluation of bovine bones to test multiple geophysical/geochemical techniques in bone research in association with QCT bone densitometry. From a medical point of view, the composition of the studied bones could be reliably examined by these methods.

Interpreting Stains

Within the field of forensic anthropology, a primary goal for investigators is the estimation of a decedent’s post-mortem interval (PMI). Given its importance, numerous unique techniques exist to aid in accurate and precise PMI determinations. However, very few of these methods thoroughly account for the timeline upon which osteologic material becomes stained by its depositional environment. The organic structure of bone allows for a unique pattern of discolouration, but it can be difficult to interpret these properly. In order to discuss the widest array of discolouring factors, the following comprises results from varied individual studies, with the specifics of each process briefly described in order to present a wider overview of each factor. Four key headings allow an organized approach to the material—(i) Soil Contents, (ii) Atmospheric Processes, (iii) Human Traces, and (iv) Nefarious Acts—with each heading discussing three common sub-discolourants. Stains arise either by natural or nefarious means, varying drastically by geographical location and climate, producing a range of observable results. The analysis concludes with an integrated discussion of the factors detailed herein, to ultimately evaluate the question of whether or not discolouration can be utilized as a reliable PMI-estimation methodology.

Hierarchical Keypoints Feature Alignment for Domain Adaptive Pose Estimation

Unsupervised Domain Adaptation (UDA) is a popular research topic in computer vision. One of the most common strategies in this field is to reduce domain shifts through global feature alignment. Unfortunately, we observe its failure on adaptive human pose estimation. From our analysis, we find out two major reasons: the extreme imbalance between keypoints and non-keypoints regions and the high diversity of human skeleton structures. To address these problems, we propose a simple yet effective approach named PoseDA. Our idea is to let the alignment focus on the feature of keypoint regions and enforce the model to learn domain-invariant representations for keypoint prediction. The key component of our PoseDA is a Hierarchical Feature Selection of Keypoints Regions (HFS) module, which consists of Coarse Feature Selection of Keypoints Regions (CFS) and Reliable Feature Selection of Keypoints Regions (RFS). By using HFS, we obtain reliable and compact keypoints features, allowing our model to achieve more effective feature alignment. Under three UDA scenarios, i.e. JTA→MPII, SURREAL→LSP, SURREAL→Human3.6, our PoseDA establishes new state-of-the-art performance. In particular, our PoseDA outperforms the previous best UDA methods by over 7% w.r.t. PCKh on JTA→MPII.

Scopolamine mitigates oophorectomy-induced osteoporosis: potential mechanisms and direct effects on bone structure

The aim of our research is to investigate the therapeutic effects of scopolamine (SCO) on osteoporosis and to explore the underlying mechanism. To study osteoporosis, we established an ovariectomy (OVX) model. The rats were divided into four groups: sham operation, OVX, OVX+SCO, and OVX+SCO+ML385 (Nrf2 inhibitor). ELISA, Realtime PCR, Western blot, and kits were utilised to assess the expression of related proteins and substances. The OVX rats exhibited significant weight gain, reduced bone volume, destruction of trabecular and cortical bone microstructure, decreased expression of ALP, OCN, OPN, COL1A1, Runx2, Nrf2 proteins, and CAT, SOD, GST, GPX levels while increased expression of TRAP protein and ROS levels. SCO was able to restore these indices in OVX rats, while ML385 blocked the effects of SCO. In conclusion, SCO inhibits oxidative stress response to exert therapeutic effects on osteoporosis by activating the Nrf2 signalling pathway.

Designing spongy-bone-like cellular materials: Matched topology and anisotropy

Bone is a natural material with properties such as high specific stiffness and strength. These exceptional mechanical properties are attributed to the meso-scale structure and elastic anisotropy of spongy bone. Replicating the topological traits and mechanical properties of spongy bone presents a novel opportunity to develop high-performance cellular materials. To achieve this, we propose an innovative framework for designing biomimetic cellular materials that match the trabecular structure and elastic anisotropy of spongy bone. This framework introduces a forward-flow design process that utilizes gradient-based feature tuning on a low-dimensional feature vector, transforming the complex inverse design problem into an efficient iterative process. A key innovation in our approach is the use of a pre-trained generative model, SliceGAN, to reconstruct 3D unit cells from 2D micro-CT images. This significantly reduces the cost and time associated with traditional layer-by-layer CT scans typically required for 3D training data. Numerical homogenization is then used to determine the effective elastic stiffness matrix, and a Fourier neural operator is trained to predict these matrices efficiently, greatly enhancing the computational efficiency of the design process. Using this framework, we successfully designed unit cells with topological traits and elastic anisotropy that closely approximate those of natural spongy bone. This opens new avenues for developing spongy-bone-mimetic cellular materials with exceptional mechanical properties. Moreover, the framework's versatility allows it to be extended to the design of other bio-inspired cellular materials.

Magnetic Resonance Assessment of Bone Quality in Metabolic Bone Diseases.

Metabolic bone diseases (MBDs) are a diverse group of diseases, affecting the mass or structure of bones and leading to reduced bone quality. Parameters representing different aspects of bone health can be obtained from various magnetic resonance imaging (MRI) methods such as proton MR spectroscopy, as well as chemical shift encoding-based water-fat imaging, that have been frequently applied to study bone marrow in particular. Furthermore, T2* mapping and high-resolution trabecular bone imaging have been implemented to study bone microstructure. In addition, quantitative susceptibility mapping and ultrashort echo time imaging are used for trabecular and cortical bone assessment. This review offers an overview of technical aspects, as well as major clinical applications and derived main findings, for MRI-based assessment of bone quality in MBDs. It focuses on osteoporosis as the most common MBD.

Использование имплантатов из пористого никелида титана в замещении тотальных дефектов скуловой кости и дуги

Summary. The aim of the study is to increase the efficiency of total replacement of the zygomatic bone and arch by developing a new medical technology using shape memory materials. Materials and methods of the study. Research materials – technologies using shape memory materials. Research method – development of an endoprosthesis of the zygomatic bone and arch. Research results and their analysis. Analysis of the research results showed: – the use of endoprostheses made of porous titanium nickelide in accordance with the anatomical features of the affected organ makes it possible to fully restore the lost anatomical and functional capabilities of the facial skull; – coating the endoprosthesis frame with textile titanium nickelide, in addition to improving the conditions for the interaction of the implant with the recipient tissues, allows to fully compensate for the insufficiency of the soft tissue component of the face; – fixing structures with a shape memory effect are easy to use, do not require significant time costs and provide stable fixation of the endoprosthesis with bone structures.

Correlative Raman spectroscopy and electron microscopy identifies glycogen rich deposits correlated with local structural defects in long bones of type IV osteogenesis imperfecta patients

Osteogenesis imperfecta (OI) is a genetic bone disease occurring in approximately 1 in 10,000 births, usually as a result of genetic mutation. OI patients suffer from increased fracture risk and - depending on the severity of the disease - deformation of the limbs, which can even lead to perinatal death.Despite extensive studies, the way in which the genetic mutation is translated into structural and compositional anomalies of the tissue is still an open question. Different observations have been reported, ranging from no structural (or chemical) differences to completely chaotic bone structure and composition.Here, we investigated bone samples from two adolescent OI-IV patients, focusing on the bone structure and chemistry in naturally occurring fractures. The exposed fracture plane allows the investigation of the structure and composition of the weakest bone plane. We do so by combining scanning electron microscopy (SEM) imaging with chemical information from Raman microscopy.The exposed fracture planes show different regions within the same tissue, displaying normal osteonal structures next to disorganized osteons and totally disordered structures, while the collagen mineralization in all cases is similar to that of a healthy bone.In addition, we also detected significant amounts of depositions of glycogen-rich, organic, globules of 250-1000nm in size. These depositions point to a role of cellular disfunction in the disorganization of the collagen in qualitative OI.Overall, our results unite multiple, sometimes contradicting views from the literature on qualitative OI.

Protective effect of carvacrol hydrogel on the alveolar bone in rats with periodontitis.

This study aimed to investigate the protective effect and mechanism of carvacrol hydrogel on the alveolar bone in rats with periodontitis. A thermosensitive hydrogel supported by carvacrol was prepared using poloxamer and hydroxypropyl methyl cellulose as matrix. SD rats were randomly divided into blank group, periodontitis group, blank hydrogel group, and low-, medium-, and high-dose hydrogel groups. The periodontitis symptoms and the CT structure of the alveolar bone were observed. The changes in liver, spleen, kidney, and periodontal tissues were observed. The related indexes of bone metabolism in serum were detected. The expression of osteoprotegerin (OPG) and nuclear transcription factor-κB (NF-κB) pathway proteins was determined by Western blot. The levels of inflammatory factors were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Carvacrol hydrogel had good slow release, biocompatibility, and cell adhesion. The periodontitis of rats in the carvacrol hydrogel group was significantly alleviated, the expression of OPG protein in gingival tissue was significantly increased (P<0.01), and the levels of receptor activator of NF-κB ligand (RANKL), receptor activator of NF-κB (RANK), NF-κB protein, and inflammatory factors were significantly decreased (P<0.01). Carvacrol hydrogel can regulate the OPG and NF-κB pathways, reduce alveolar bone absorption, and improve periodontal inflammation.

3D-printed biomimetic bone scaffold loaded with lyophilized concentrated growth factors promotes bone defect repair by regulation the VEGFR2/PI3K/AKT signaling pathway

This study investigates the effects of concentrated growth factors (CGF) and bone substitutes on the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs), as well as the development of a novel 3D-printed biomimetic bone scaffold. Based on the structure of cancellous bone, 3D-printed bionic bone with sustainable release of growth factors and Ca2+ was prepared. Using BMSCs and EA.hy926 in co-culture with the bionic bone scaffold, experimental results demonstrate that this bionic structural design enhances cell proliferation and adhesion, and that the bionic bone possesses the ability to promote bone and vascular regeneration directly. Transcriptomics, western blot analysis, and flow cytometry are employed to investigate the effects of CGF and Ca2+ on the signaling pathways of BMSCs. The study reports that vascular endothelial growth factor (VEGF) released by CGF activated VEGFR2 on BMSCs, leading to Ca2+ influx and activation of the PI3K/AKT signaling pathway, thereby influencing osteogenesis. Animal experiments confirm the ability of the bionic bone to promote osteogenesis in vivo, and its unique degradation pattern accelerates the in vivo repair of bone defects. In conclusion, this study presents a novel biomimetic strategy and, for the first time, explores the potential mechanism by which VEGF and Ca2+ regulate BMSCs differentiation through the VEGFR2/PI3K/AKT signaling pathway. These insights offer a new perspective for the development of innovative bone substitute materials.

Evaluation High-Resolution Computed Tomography (HRCT) Of Temporal Bone In Cholesteatoma Of Middle Ear In Comparison With Histopathological Findings: A Prospective Study

Background: Cholesteatoma is relatively common and potentially dangerous disease of the ear. It is characterised by local destruction and osseous erosion leading to complications. Pre-operative assessment of middle ear cholesteatoma is a must for assessing the disease's location, extent, and complication. High resolution computed tomography (HRCT) is the imaging modality of choice for evaluation of middle ear structures and pathology. Therefore, in the present study we aimed to evaluate HRCT of temporal bone in cholesteatoma of middle ear cleft in comparison with histopathological results. Materials and Methods: This is a prospective study carried out on total of 30 patients who were undergoing HRCT of temporal bone for middle ear cleft pathology and found to have imaging evidence of chronic otomastoiditis on HRCT, subsequently undergoing surgery and histopathological validation. Results: The mean age of study subjects was found to be 23.97 ± 11.30 years. Majority of the study subjects were belonged to age group of 11-40 years (40%) with female predominance (53.3%) as compared to male (46.7%). Majority of the patients i.e., 60% showed signs of loss of aeration and sclerosis of mastoid air cells followed by soft tissue density lesions (43.3%), bony erosions (26.7%), and bony expansions (6.7%). Surgical findings and histopathological reports were correlated with pre-operative HRCT scans analyses with 95.88% accuracy. Conclusion: Compared to histopathological findings, HRCT offers a diagnostic capacity that is remarkably sensitive and specific in identifying cholesteatoma and the condition of the bone structures in the temporal bone