Bone is a highly dynamic tissue undergoing continuous remodelling through the coordinated actions of osteocytes, osteoblasts and osteoclasts. This process is tightly regulated by key signalling pathways, including the RANK/RANKL/Osteoprotegerin system, which governs bone resorption and formation. In addition, the CXCL12/CXCR4 axis and G-protein-coupled receptor 4 (GPCR4) play crucial roles in bone development, remodelling, and pathological conditions such as cancer progression. Skeletal metastases arise from complex interactions between tumour cells and the bone microenvironment, facilitating arrest, extravasation, and colonisation at secondary sites. In osteosarcoma and metastatic cancers, these molecular mechanisms contribute to tumour growth, bone degradation, bone formation and disease progression. This review highlights the intricate crosstalk between bone remodelling pathways and tumour cell invasion, providing insights into potential therapeutic targets for osteosarcoma and bone metastases.

Catecholamines are known to interact with bone and cartilage cells via binding to adrenergic receptors. Among these, the β2-adrenoceptor (β2-AR) plays a key role in mediating the effects of catecholamines on bone. Mice lacking the β2-AR systemically or specifically in osteoblasts show an increased bone mass. Previous studies further indicated an important influence of catecholamines on transdifferentiation of chondrocytes towards osteoblasts during endochondral ossification. Therefore, in this study, cartilage and bone phenotype as well as fracture healing of mice with a specific knockout of the β2-AR in chondrocytes were investigated. Tibiae and femora of 6-, 12-, and 40-wk-old male and female mice were analyzed. The knockout resulted in a reduced long bone growth, most likely due to a faster transition of proliferative to hypertrophic chondrocytes. The older knockout mice additionally showed an osteopenic bone phenotype due to a reduced number of osteoblasts. Fracture healing after a standardized femur osteotomy was delayed, showing reduced cartilage area at an intermediate time point during fracture healing. Gene expression analysis in an additional in-vitro-experiment identified pathways like "Wnt-signaling" and "TGFβ-signaling" to be involved. In conclusion, our data showed an important role of the β2-AR specifically in chondrocytes during long bone growth, bone homeostasis in older animals and fracture healing.

Effects of the Dental Implant Surface Topography and Macrophage Polarisation on Osteogenesis and Angiogenesis.

Bone is a dynamic tissue that is maintained through the co-ordination of bone resorption and bone formation. An imbalance of these processes can lead to bone disease. In vitro studies of osteoblasts can help to understand bone formation, but primary cells have a limited lifespan in culture. Herein, we report the successful generation of equine immortalized osteoblasts through the stable overexpression of human telomerase reverse transcriptase (hTERT) and Simian virus 40 (SV40) large T-antigen in osteoblasts isolated from trabecular bone taken from the third metacarpal of a two-year-old Thoroughbred horse. Primary osteoblasts displayed limited proliferation in culture, a decrease in the expression of osteogenic-associated genes and alkaline phosphatase activity with increasing passage and a failure to survive and produce a mineralised matrix after 21 days of osteogenic culture at high passage. In contrast, immortalized equine osteoblasts could be expanded for over 50 passages while retaining osteogenic gene expression, high alkaline phosphatase activity, a normal karyotype and the ability to produce a mineralised matrix after osteogenic culture. The immortalized equine osteoblasts therefore constitute a useful in vitro model to study equine bone formation.

Liraglutide enhances bone regeneration in a critical-size calvarial defect model in male rats: A comparative study with autogenous grafts, allografts, and xenografts.

Artesunate ameliorates Staphylococcus aureus-induced mandibular osteomyelitis and promotes osteogenic differentiation via NOD2/p65 signaling pathway.

Ginger extract release from 3D printed calcium phosphate scaffolds for bone regeneration.

Glass fiber-reinforced composite-bioactive glass (FRC-BG) implants are emerging as an alternative to autologous bone grafts with the potential for new bone formation and ingrowth from the surrounding skull. However, clinical evidence of osseointegration remains to be demonstrated. To evaluate radiological measures of osseointegration of FRC-BG implants used for cranioplasty. A retrospective cohort study was conducted including adult patients who underwent cranioplasty with FRC-BG implants between 2016 and 2021. Sequential non-contrast head CT-scans were obtained within 24h postoperatively and after one year of follow-up. Using three-dimensional (3D) segmentation and analysis software, changes in bone volume (in cm3) and bone density (in Hounsfield units [HU]) of a standardized one cm-wide region of skull bone surrounding the margins of the FRC-BG implants were quantified. Paired samples t-tests assessed differences between baseline and after one year of follow-up. A total of 38 patients were included (mean age 50.2±18.4years). After one year of follow-up, significant increases were observed in both skull bone volume (mean difference 6.04cm3, 95% confidence interval [CI] 4.65-7.43, p<0.001) and skull bone density (mean difference 45.84 HU, 95% CI 1.15-90.52, p=0.045) surrounding the FRC-BG implants. The present study shows radiological signs of osseointegration of FRC-BG implants used for cranioplasty.

Compromised bone quality and quantity in the posterior maxilla are widely recognised as significant risk factors for implant failures. This study aimed to (1) assess the bone quality of the resorbed posterior maxilla both radiographically and histologically and (2) evaluate the impact of native alveolar bone quality on osteogenesis following maxillary sinus floor augmentation (MSFA). Patients presenting advanced posterior maxillary atrophy (residual bone height ≤ 4 mm) underwent MSFA via a lateral window approach using deproteinised bovine bone matrix (DBBM). Bone core biopsies were collected during second-stage implant placement for histological analyses. Preoperative cone-beam computer tomography (CBCT) images were used to classify bone quality based on cortical bone configuration. Multiple linear regression was employed to identify factors influencing osteogenesis. A total of 190 sinuses from 176 patients (96 males/80 females, mean age: 45.77 ± 4.13 years) underwent MSFA and biopsy. Radiographic analysis revealed the presence of bicortical bone in 42.21% of the maxillary ridges, unicortical bone in 25.97%, no cortical bone in 19.48% and sinus floor-crestal bone fusion in 12.34%. Histologically, native bone comprised 40.01% ± 14.85% of mineralised trabeculae while newly formed bone accounted for 18.77% ± 5.69% in the DBBM grafted areas. A significant positive correlation was observed between native bone trabecula percentage and new bone formation (r = 0.23, P = .04). No significant associations were found with age, sex, healing time or radiographic alveolar type (P > .05). Greater density of native trabecular bone may contribute to enhanced osteogenesis following MSFA. This study enhances our understanding of the bone characteristics of the resorbed posterior maxilla. It emphasises the need to consider the bone quality of the recipient site before conducting a MSFA for determining the surgical procedure and predicting the prognosis.

Functional iron oxide nanoparticles cross-linked hydrogel for craniofacial bone regeneration.

Characteristics of osteoclasts at different developmental stages and therapeutic strategies.

Wet-adhesive metabolic hydrogel for osteoimmune-guided extraction socket healing.

Sensory neuron TRPV1-mediated macrophage polarization and immune response regulate dental implant osseointegration.

Supercritical CO2-foamed hierarchically porous PLA/PBS-based scaffold for advanced bone regeneration.

This review focuses on experimental models developed to study myeloma bone disease (MBD), a major cause of morbidity in multiple myeloma (MM). Under physiological conditions, bone remodeling is regulated by osteoclasts (OCs) and osteoblasts (OBs); in MM, this balance is disrupted, resulting in enhanced bone resorption and suppressed bone formation. Myeloma cells alter the bone marrow (BM) microenvironment by increasing the RANKL/OPG ratio and secreting Wnt pathway inhibitors such as DKK-1 and sclerostin, thereby promoting osteoclastogenesis and inhibiting osteoblast differentiation. To dissect these mechanisms and evaluate therapeutic strategies, diverse preclinical systems have been developed. Syngeneic murine models, notably the 5T series, remain the most established for reproducing both osteolysis and impaired bone formation, though interspecies differences limit translational relevance. Humanized mouse systems and three-dimensional (3D) in vitro models increasingly address these constraints by incorporating human stromal and hematopoietic elements. Emerging induced pluripotent stem cell-derived bone marrow organoids (iBMOs) offer a fully human platform capable of modeling both osteoclast and osteoblast dynamics. While current iBMOs lack mineralized bone and mature vascular or immune components, advances in differentiation control and matrix engineering are expected to bridge these gaps, providing physiologically relevant and ethically sustainable models for studying MBD and testing therapeutic interventions.

Hypocalcemia is frequent in horses with colitis. Information on serum parathyroid hormone (PTH) concentrations and its association with bone turnover biomarkers in horses with colitis is lacking. We aimed to determine the association between serum bone resorption biomarkers (C-terminal telopeptide of type I collagen [CTX-I]) and bone formation (osteocalcin [OCN]) with blood PTH, total calcium (tCa), ionized calcium (iCa), phosphorus (Pi), and total magnesium (tMg) concentrations, and mortality in horses with acute colitis. A total of 163 horses were divided into colitis (n = 127) and healthy (n = 36) groups. Blood samples were collected from all horses. Non-parametric methods were used for data analysis. In horses with colitis, serum CTX-I and PTH concentrations were significantly higher, whereas OCN, tCa, iCa, Pi, and tMg concentrations were lower compared to healthy horses (P < 0.05). In colitis horses with ionized hypocalcemia, serum CTX-I concentrations were positively correlated with PTH concentrations (P < 0.05). Colitis horses with iCa concentrations < 1.4 mmol/L and PTH > 92.9 pg/mL were more likely to die ([OR = 6.1; 95 % CI = 1.2-24.5; P < 0.05]; [OR = 3.6; 95 % CI = 1.3-10.1; P < 0.05]), respectively. In colitis horses, elevated PTH and CTX-I concentrations, together with decreased OCN concentrations, suggests that bone turnover activity was increased to offset hypocalcemia. Elevated PTH and hypocalcemia were associated with non-survival, indicating that in non-surviving horses, bone resorption activity was not sufficient to restore normocalcemia. PTH resistance could have contributed to hypocalcemia in some horses with acute colitis.

Oligosaccharides ameliorate insulin resistance and hepatic metabolism by promoting the leptin/POMC axis to accelerate short stature growth and development.

Impact of coding and non-coding SNPs in the FZD8 gene on structural and functional alterations associated with tumorigenesis: A multi-faceted computational approach.

The role of neprilysin in musculoskeletal diseases.

JAK1/STAT3 signalling in cortical bone development, growth and maintenance.