Search Results (579)

Background: Osteoblast senescence constitutes one of the major mechanisms in bone degeneration and is under tight regulation by metabolism and oxidative stress. While hypoxia has recently emerged as an important microenvironmental factor influencing the function of bone cells, its role in osteoblast senescence and metabolic regulation has yet to be defined. Methods: The present work entails hypoxia-modulated osteoblast senescence at one level, transcriptomic and metabolomic sequencing, and two levels, in vitro MC3T3-E1 and in vivo AAV-shAtp6v1a mouse models. In transcriptome profiling, hypoxia-responsive genes were identified, whereas non-targeted metabolomics was used to uncover metabolic alterations induced by ATP6V1A knockdown. Oxidative stress and mitochondrial function were assessed by qRT-PCR, Western blotting, SA-β-Gal staining, ROS detection, JC-1 mitochondrial potential, and immunofluorescence. Micro-CT, H&E, Masson, and immunohistochemistry studies were performed to investigate bone structure and protein expression in vivo. Results: Hypoxia markedly mitigated osteoblast senescence, decreasing p53 and p21 expressions and the number of SA-β-Gal-positive cells. It reduced intracellular ROS levels and increased HK2 and LDH expression, decreased ATP, and increased lactate, hinting at a shift toward glycolysis. Transcriptome analysis identified ATP6V1A as one of the major hypoxia-downregulated genes. Knockdown of ATP6V1A reduced ROS levels, inhibited p21 expression, improved mitochondrial function. Metabolomics disclosed remapping pathways in glycolysis, lipid, and amino acid metabolism. Conclusion: This study identifies a “Hypoxia–ATP6V1A–Oxidative Stress–Metabolic Remodeling–Anti-Senescence” axis, demonstrating that hypoxia delays osteoblast senescence by downregulating ATP6V1A, suppressing oxidative stress, and reprogramming metabolism, providing new insights and potential therapeutic targets for bone degenerative diseases. Full article

Background: Aural fullness is a common symptom in routine otolaryngological practice. Although it is most commonly attributed to cerumen impaction, other, less frequent conditions may present similar symptoms and are often initially misdiagnosed as cerumen. These include keratosis obturans (KO) and external auditory canal cholesteatoma (EACC). Accurate differentiation among these entities is crucial for appropriate management. These distinctions are crucial for appropriate management. Methods: We retrospectively reviewed 100 patients who presented with a chief complaint of aural fullness from 2021 to 2025. All patients underwent microscopic and/or micro/endoscopic otologic evaluation and were subsequently treated with outpatient otologic procedures. These procedures ranged from simple cerumen removal for CI cases to aural toilettage of the external auditory canal for KO and initial debridement attempts for EACC. Results: Among 100 patients, 87 were diagnosed with CI, 10 were diagnosed with KO, and 3 were diagnosed with EACC. In 97 patients, outpatient microscopic management was effective and successful, leading to the complete removal of the underlying condition and resolution of the ear fullness. In the remaining 3 cases—all diagnosed with EACC—microscopic outpatient debridement was not sufficient. These patients were subsequently scheduled for surgical intervention following audiological and temporal bone CT evaluations. Conclusions: Our findings confirm that CI is the most frequent cause of aural fullness and that microscopic outpatient removal represents an excellent standard of care. However, clinicians should remain aware that KO and EACC may present similar symptoms. Their management is often more complex, potentially requiring multiple sessions and, in the case of EACC, can necessitate surgical intervention. Accurate diagnosis is, therefore, essential to ensure effective and appropriate treatment. Full article

This paper provides a comprehensive overview of the application of various radiological modalities, with a critical comparison between human and veterinary medicine. The modalities discussed include conventional radiography, dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), quantitative ultrasound (QUS), positron emission tomography-computed tomography (PET-CT) and micro and nano computed tomography (micro-CT, nano-CT) in clinical practice and basic research of skeletal system. Radiological imaging plays a crucial role in the diagnosis, monitoring and research of skeletal system disorders in both human and veterinary medicine. In preclinical research, advanced diagnostic imaging modalities such as micro-CT and nano-CT allow for 3D quantification of trabecular and cortical bone microarchitecture for studies in bone biology, regenerative medicine and pharmacological research. Furthermore, the integration of artificial intelligence is advancing image interpretation, precision diagnostics and disease tracking. Despite their broad utility, imaging modalities must be selected based on clinical indication, species, age and anatomical region with consideration of radiation dose, cost and availability, especially in remote regions. For this reason, clinicians and radiologists remain an irreplaceable part of diagnostic imaging. Full article

Background: Bone fracture is a partial or complete break in the continuity of a bone, which poses a significant healthcare burden. It is important to discover a novel method to stimulate and speed-up the healing of bone fractures. Aim: This study aimed to investigate the effects and mechanisms of alternating current (AC) in promoting bone fracture healing. Methods: A rabbit bone fracture model was used. X-ray and Micro-CT evaluated fracture healing, while HE staining and immunohistochemistry assessed morphological changes. In vitro, pre-osteoblastic cells were tested with alizarin red S staining and alkaline phosphatase (ALP) activity. RNA-seq analysis explored potential mechanisms. Results: X-ray evaluation showed that alternating current stimulation (ACS) promoted bone formation and shaping by day 14 post-treatment. Micro-CT results revealed significant new bone formation as early as day 3 and day 7 (p < 0.05). HE staining indicated more trabecular bone formation in the ACS group compared to the model group at days 7 and 14. Immunohistochemistry showed higher expression of BMP-2 and VEGF in the ACS group by day 7. In vitro, ACS enhanced osteogenic differentiation, increasing calcified nodule formation and ALP activity. Gene expression analysis demonstrated significant changes in key osteogenic genes, confirmed by multiple immunohistochemical staining. Conclusions: ACS may be a novel method for treating bone fractures more rapidly, significantly relieving the patient’s burden, particularly in the early stages of bone healing. Full article

The repair of large segmental bone defects remains a major clinical challenge. Traditional bone repair materials often suffer from mismatched degradation rates, insufficient mechanical strength, or limited bioactivity. Biodegradable zinc alloys have emerged as potential alternatives due to their suitable degradation rate and good biocompatibility, though their bioactivity requires further enhancement. In this study, a zinc phosphate (ZnP) coating was applied on the surface of zinc–copper (Zn–Cu) alloy via a phosphate chemical conversion method, and the corrosion resistance, wear resistance, and osteogenic properties of the coating were systematically evaluated. Results showed that the ZnP coating prepared at pH = 2.5 exhibited a dense structure and high crystallinity, reducing the corrosion rate to 0.010 μm/year and increasing the ultimate tensile strength to 117.03 ± 0.78 MPa, significantly improving the wear and corrosion resistance of the alloy. In vivo experiments demonstrated that the material markedly promoted new bone formation and osseointegration. Micro-computed tomography (Micro-CT) revealed that key indicators such as bone volume fraction (approximately 50.26%) and trabecular number (approximately 161.31/mm³) were superior to those of the β-tricalcium phosphate (β-TCP) group and the control group. Histological analysis confirmed its excellent osteogenic activity and mineralization capacity. Biosafety assessments indicated no systemic toxic reactions. The ZnP-coated Zn-1Cu alloy showed promising application in treatment of bone defect. Full article

Estrogen deficiency is a primary cause of osteoporosis, compromising bone mineral density that may impair peri-implant healing. Given the compromised bone environment associated with estrogen deficiency, strategies such as particle reduction via sonochemistry are promising approaches to enhance regenerative outcomes. However, its effects in promoting bone formation remain insufficiently explored. Therefore, this study evaluated the potential of two sonicated biomaterials to improve peri-implant repair in ovariectomized rats. Fifty female rats were allocated into five groups: blood clot (CLOT), Biogran^® (BGN), sonicated Biogran^® (BGS), Bio-Oss^® (BON), and sonicated Bio-Oss^® (BOS). Tibial peri-implant defects were created 30 days after ovariectomy and analyzed 28 days later by removal torque, microcomputed tomography, and confocal microscopy. BGS exhibited the highest removal torque (6.28 Ncm), followed by BON (5.37 Ncm), BOS (3.92 Ncm), BGN (3.15 Ncm), and CLOT (2.58 Ncm). Micro-CT revealed bone volume fraction (BV/TV) values of 8.07% (CLOT), 6.47% (BOS), 6.02% (BGS), 5.55% (BGN), and 2.84% (BON). For the trabecular number (Tb.N), BGS (1.11 mm⁻¹) showed a significant increase compared with BGN (0.69 mm⁻¹), p < 0.05. These findings show that sonochemically modified bioactive glass improves mechanical stability and trabecular microarchitecture under estrogen-deficient conditions. However, further studies are needed to standardize sonication parameters for different biomaterials and expand their translational applicability. Full article

Additive manufacturing (AM) has rapidly evolved due to its design flexibility, ability to enable personalized fabrication, and reduced material waste. In the medical field, fused filament fabrication (FFF) facilitates the production of individualized anatomical models for surgical preparation, education, medical imaging, and calibration. However, the lack of filaments with X-ray attenuation similar to that of biological hard tissues limits their use in radiological imaging. To address this limitation, a radiopaque filament was developed by incorporating gadolinium oxide (Gd₂O₃) into a biodegradable poly(lactic acid) (PLA) matrix at 1, 3, and 5 wt.%. Thermal and rheological properties were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and melt flow index (MFI) analyses, revealing minor variations that did not affect printability under standard FFF conditions (200 °C nozzle, 60 °C build plate, 0.12 mm layer height). Microstructural analysis via field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, and micro-computed tomography (micro-CT) confirmed homogeneous Gd₂O₃ dispersion without nozzle blockage. Radiopacity was evaluated using gyroid infill cubes, and increasing Gd₂O₃ content enhanced X-ray attenuation, with 3 wt.% Gd₂O₃ reaching Hounsfield Unit (HU) values comparable to cortical bone. Finally, the L1 vertebra phantom fabricated from the 3 wt.% Gd₂O₃ filament exhibited mean HU values of approximately +200 to +250 HU at 50% infill density (trabecular bone region) and around +1000 HU at 100% infill density (cortical bone region), demonstrating the filament’s potential for producing cost-effective, radiopaque, and biodegradable phantoms for computed tomography (CT) imaging. Full article

Microneedle array-based drug delivery offers a minimally invasive and safe approach for breaching the skin barrier, enabling localized and targeted treatment—an advantage particularly valuable in chronic condition management, such as rheumatoid arthritis (RA). RA presents a multifaceted pathophysiology, often necessitating long-term pharmacological management. However, conventional oral administration may lead to systemic drug distribution, increasing the likelihood of adverse effects, and ultimately undermining therapeutic efficacy. In this study, a hollow microneedle array was employed for effective delivery of Tofacitinib and the antioxidant N-acetylcysteine (NAC). A comprehensive evaluation was conducted across multiple levels, in which inflammation and cartilage degradation were assessed histologically using hematoxylin-eosin (H&E) and Safranin O–Fast Green staining. Radiologically, micro-computed tomography (micro-CT) was employed to visualize bone structure alterations. On the molecular level, enzyme-linked immunosorbent assay (ELISA) was used to quantify inflammatory cytokines and oxidative stress markers. Furthermore, differentially expressed genes and enriched signaling pathways were identified through transcriptomic profiling pre- and post-treatment. And the potential regulatory targets and mechanistic insights into the therapeutic response were elucidated through correlation analyses between gene expression profiles and pathological indicators. This study provides a mechanistic and computational basis for precision targeted therapy, validates the efficacy and safety of microneedle delivery in a rheumatoid arthritis (RA) model, and demonstrates its potential application in local drug delivery strategies. Full article

Regeneration of jawbone defects poses major challenges. The combination of dental pulp stem cells (DPSCs) or DPSC-derived extracellular vesicles (EVs) with bone substitute materials shows promising potential for bone tissue engineering in vitro. This study evaluated the in vivo bone regeneration potential of DPSCs and EVs with bone graft substitutes in a novel intrabony defect model. DPSCs were isolated from 35 male Sprague–Dawley rat incisors, and EVs were collected from the cell culture medium. DPSCs were seeded onto alloplastic and xenogeneic bone graft materials and implanted into bone defects. Control groups received bone substitutes without DPSCs or EVs. Micro-computed tomography (µCT) was performed at 12 and 24 weeks post-implantation to assess bone volume (BV), bone density (BD), trabecular thickness (Tr.Th), bone growth rate (BGR), and bone-to-mineral ratio (BMR). Both graft types increased BV and BD, with no significant differences between them. Tr.Th increased across all treatments after 24 weeks, indicating ongoing bone remodeling. Notably, xenogeneic grafts combined with DPSCs and EVs significantly improved BGR (p = 0.034) and BMR (p = 0.021) compared to alloplastic grafts with DPSCs. Xenogeneic bone grafts combined with DPSCs and EVs appear to be a promising approach for bone regeneration of alveolar bone defects. Full article

Alzheimer’s disease (AD) and osteoporosis frequently co-occur in the elderly; however, the pathophysiological link between these two diseases remains unclear. This study investigates skeletal alterations in a triple transgenic 3xTg-AD mouse model of AD (3xTg-AD), which harbors mutations in β-amyloid precursor protein (βAPP_Swe), presenilin-1 (PS1_M146V), and tau_P301L, and recapitulates key aspects of AD pathology, including age-dependent β-amyloid plaque accumulation and cognitive decline. To assess early skeletal changes, we analyzed femurs and tibiae of 2-month-old male non-Tg and 3xTg-AD mice (n = 9/group) using micro-CT. Despite the absence of β-amyloid plaques at this stage, 3xTg-AD mice showed significant cortical bone loss, with reduced bone surface, periosteal and endosteal perimeters, total and cortical cross-sectional area, and polar moment of inertia. The 3-point-bending test confirmed compromised mechanical properties, including reduced maximum load-to-fracture and stiffness. Histological analyses highlighted an increased number of Empty Osteocyte Lacunae, reduced TRAP⁺ osteocytes, and an elevated number of osteoclasts; such evidence indicates impaired osteocyte function and increased bone resorption. These findings indicate that cortical bone loss and compromised mechanical properties occur before detectable neuropathological hallmarks in this AD model. Full article

Background: RT-qPCR is the gold standard for quantitative gene expression analysis, but it requires homogenized tissue and thus loses spatial information. RNA in situ hybridization (ISH) preserves tissue localization but is technically challenging, especially in calcified tissues such as bone and teeth, where decalcification can damage RNA. RNAscope, an advanced ISH method with high sensitivity and specificity, has been applied successfully to bone, but its use in dental pulp remains largely unexplored despite the pulp’s crucial role in tooth function and health. Our goal was to identify the optimal decalcification process of mouse tooth samples for RNAscope ISH, which preserves RNA integrity in mouse tooth pulp. Methods: We tested five different decalcification procedures (EDTA, Plank-Rychlo solution, 5% formic acid, ACD decalcification buffer and Morse solution) on tooth samples from 3-month-old male C57BL/6J mice. Micro-CT and hematoxylin-eosin (HE) staining was performed to evaluate the decalcification, the quality and the microstructure of the sections. RNAscope ISH was used to examine mRNA integrity by analyzing the expression patterns of three housekeeping genes with different expression levels (low, medium and high). Results: All five decalcification methods demonstrated well-preserved tissue structure based on HE staining, but RNA integrity was only preserved in the case of mouse dental pulp using the ACD decalcification buffer and Morse’s solution. Conclusions: We successfully identified the optimal decalcification procedures preserving RNA integrity in mouse tooth samples, which may be useful for any target RNA examinations by RNAscope ISH in the future. Full article

Background/Objectives: This study evaluates photon-counting CT (PCCT) for the imaging of mouse femurs and investigates how APOE genotype, sex, and humanized nitric oxide synthase (HN) expression influence bone morphology during aging. Methods: A custom-built micro-CT system with a photon-counting detector (PCD) was used to acquire dual-energy scans of mouse femur samples. PCCT projections were corrected for tile gain differences, iteratively reconstructed with 20 µm isotropic resolution, and decomposed into calcium and water maps. PCD spatial resolution was benchmarked against an energy-integrating detector (EID) using line profiles through trabecular bone. The contrast-to-noise ratio quantified the effects of iterative reconstruction and material decomposition. Femur features such as mean cortical thickness, mean trabecular spacing (TbSp_mean), and trabecular bone volume fraction (BV/TV) were extracted from calcium maps using BoneJ. The statistical analysis used 57 aged mice representing the APOE22, APOE33, and APOE44 genotypes, including 27 expressing HN. We used generalized linear models (GLMs) to evaluate the main interaction effects of age, sex, genotype, and HN status on femur features and Mann–Whitney U tests for stratified analyses. Results: PCCT outperformed EID-CT in spatial resolution and enabled the effective separation of calcium and water. Female HN mice exhibited reduced BV/TV compared to both male HN and female non-HN mice. While genotype effects were modest, a genotype-by-sex stratified analysis found significant effects of HN status in female APOE22 and APOE44 mice only. Linear regression showed that age significantly decreased cortical thickness and increased TbSp_mean in male mice only. Conclusions: These results demonstrate PCCT’s utility for femur analysis and reveal strong effects of sex/HN interaction on trabecular bone health in mice. Full article

Background: Although teriparatide is efficacious, its once-daily subcutaneous injections cause local adverse events, inconvenience, and higher cost, limiting long-term adherence. Therefore, this research aims to engineer a pH-responsive oral formulation of teriparatide for osteoporosis therapy. Methods: A layered silicate nanocomplex was obtained by spontaneous self-assembly of teriparatide (Teri) with 3-aminopropyl magnesium phyllosilicate (AC). The nanocomplex (AC-Teri) was then coated with a 1:1 blend of two polymethacrylic acid derivatives (Eudragit^® L100 and Eudragit^® S 100) to provide pH-triggered drug release along the gastrointestinal tract. Results: AC-Teri and the coated nanocomplex (EE/AC-Teri) displayed high encapsulation efficiency (>90%) with narrow size distributions. In a stepwise buffer transition system, EE/AC-Teri demonstrated pH-dependent release, with less than 25% drug liberated at pH 1.2, approximately 54% at pH 6.8, and 74% at pH 7.4 over 24 h. Particle size and ζ-potential of EE/AC-Teri shifted in parallel with dissolution of the outer polymer shell. EE/AC-Teri also protected the peptide against enzymatic degradation, preserving the secondary structure of encapsulated teriparatide in simulated intestinal fluids. Compared with free drug, EE/AC-Teri enhanced transcellular drug permeation 2.7-fold in Caco-2 cells. In dexamethasone-induced osteoporotic rats, oral EE/AC-Teri significantly stimulated bone formation while suppressing resorption; micro-CT and histology confirmed recovery of trabecular architecture. Conclusions: EE/AC-Teri represents a promising oral teriparatide formulation for the effective management of osteoporosis. Full article

Background/Objectives: Regenerating critical-sized bone defects is a significant clinical challenge. Autogenous bone grafts are the gold standard but have limitations, including donor site morbidity. As an alternative, this study introduces a novel biocomposite combining an ethyl cyanoacrylate (ECA) polymer with Hancornia speciosa (Hs) latex. The ECA acts as a scaffold and delivery vehicle for the latex, which contains phytochemicals with known angiogenic properties. Methods: We created 5 mm critical-sized calvarial defects in 36 Wistar rats, which were divided into four experimental groups. Bone regeneration was evaluated at 30, 60, and 90 days using micro-computed tomography (micro-CT) for morphometric analysis and hematoxylin and eosin staining for histology. Results: The composite-treated group (Hs+ECA) showed significantly higher bone volume (57.2; IQR: 56.7–61.2) than the control (53.9; IQR: 49.4–56.4) and ECA-only (48.4; IQR: 47.2–59.9) groups at 90 days (p < 0.05). By day 60, the bone volume in the Hs+ECA group was statistically similar (p > 0.05) to that of the autogenous bone group. Histological analysis revealed an organized repair process with neoangiogenesis observed only in the Hs+ECA group, confirming the material’s strong bioactivity. Conclusions: The Hs+ECA composite is a promising biomaterial that acts as an effective delivery system for the bioactive components of the latex. The induced angiogenesis was critical to its regenerative success. This cost-effective material warrants further investigation for clinical applications in regenerative dentistry. Full article

Developing bone substitutes that are mechanically strong, highly biocompatible and capable of controlled degradation is crucial for successful bone regeneration. Magnesium phosphate cements (MPCs) and calcium magnesium phosphate cements (CMPCs) offer higher strength and solubility than established calcium phosphate cements (CPCs). This study aimed to evaluate the in vivo degradation, osteoregeneration and biocompatibility of 3D powder-printed Mg3d (Mg₃(PO₄)₂) and Mg275d (Ca_0.25Mg_2.75(PO₄)₂) scaffolds with alkaline post-treatment, using structurally identical TCP (Ca₃(PO₄)₂) scaffolds as the control. The scaffolds were implanted into the lateral femoral condyle of adult female Zika rabbits and analysed up to 6, 12 and 24 weeks using radiography, microCT, histology, EDX and SEM. All materials demonstrated good biocompatibility. Mg3d and Mg275d scaffolds degraded significantly faster than the TCP scaffolds, with nearly complete degradation after 12 weeks. A cell-rich reconstruction zone formed during degradation, which was subsequently replaced by new bone. The degradation rate of the scaffolds corresponded closely to bone regeneration. Notably, the Mg3d and Mg275d scaffolds supported the faster formation of mature lamellar bone compared to the TCP scaffolds. These results indicate that magnesium phosphate (MgP)-based scaffolds represent a promising alternative to conventional calcium phosphate (CP)-based bone substitutes, given their rapid and almost complete degradation and their effective support of bone regeneration. Full article