Effect of amoxicillin on cartilage and bone development in zebrafish and their molecular mechanisms.

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.

Retrospective review of electronic health records system. To compare the indications and complication rates between rhBMP-2 and non-rhBMP-2 use in spine fusion at a high-volume tertiary orthopedic institution. Bone morphogenetic proteins are growth factors that play a critical role in bone development and proliferation. rhBMP-2 is a biological approved for select spinal fusion procedures to improve fusion rates. It is used in off-label indications. There are limited studies describing the use of rhBMP-2 in current practice. Patients who underwent spinal fusion from February 2016 to January 2022 were included. Surgery types were categorized by the approach listed as the primary procedure. A subgroup analysis was performed to assess differences in rhBMP-2 use for short and long fusions. Complications present within one year as ICD-10 codes were assessed. A total of 9809 patients were assessed. rhBMP-2 was used in 0.3% of ACF and 64.5% of PCF surgeries. Patients who underwent PCF with rhBMP-2 had higher rates of osteoporosis. rhBMP-2 was used in 96.1% of AL/TF, 69.2% of PL/TF, 97.4% of LLIF, and 24.1% of TLIF. Patients who underwent PL/TF with rhBMP-2 had higher rates of osteoporosis, mean age, former smoking status, and ASA class. There were increased rates of wound dehiscence in PL/TF with rhBMP-2. Patients who underwent long fusions with rhBMP-2 were more likely to have osteoporosis than those who underwent short fusions without rhBMP-2. We found that rhBMP-2 was used extensively in AL/TF and LLIF, frequently in PCF and PL/TF, occasionally in TLIF, and sparingly in ACF. While patterns of use differed in the cervical spine, mostly selecting for patients with risk factors for pseudarthrosis, this pattern of usage was only found in posterior lumbar and thoracic fusion. There was no obvious trend in complications associated with rhBMP-2 use.

Down syndrome (DS) is caused by the triplication of human chromosome 21 (Hsa21), resulting in skeletal insufficiency (low bone mineral density) and altered bone development. DS mouse models recapitulate these deficits, including sexual dimorphism in long bone alterations. Historically, Ts65Dn mice provided much of the insight behind DS-related skeletal deficits with ∼100 trisomic orthologous genes, but there are concerns about the genetic fidelity in this model due to the included triplication of genes not homologous to Hsa21. A new DS model, Ts66Yah, subtracted the non-Hsa21 homologous trisomic genes from Ts65Dn but has not been evaluated for long bone deficits. Comparing skeletal phenotypes between these models can determine the contribution of non-Hsa21 homologous trisomic genes and whether the Ts66Yah mouse is relevant as a model for DS-associated skeletal deficits. After assessing individual densitometric, morphometric, and mechanical variables in male and female Ts66Yah femurs at similar ages to when skeletal deficits were observed in Ts65Dn mice, structural phenotypes were directly compared to those of Ts65Dn mice using a novel multivariate principal components analysis method to generate composite scores. Overall, structural and mechanical bone phenotypes of the femur appeared milder in Ts66Yah compared to Ts65Dn mice. The appearance of developmental trabecular microarchitecture deficits, but not other abnormalities, were evident earlier in Ts65Dn than Ts66Yah mice. Dyrk1a, a gene triplicated in both models, affected skeletal structure differently in each model, likely through differing gene interactions. The novel principal components analysis detected subclinical phenotypes lost in individual analyses, which could be advantageous when determining overall skeletal deficits.

Dento-maxillofacial abnormalities are highly prevalent and arise as a result of a variety of etiological factors, presenting substantial challenges to treatment. The JAK-STAT signaling plays a pivotal role in dentofacial development, regulating endochondral ossification, intramembranous ossification, dental follicle formation, and enamel development. Mutations in the JAK-STAT signaling lead to syndromes associated with severe dento-maxillofacial abnormalities, including Growth Hormone Insensitivity Syndrome and Autosomal Dominant Hyper-IgE Syndrome. Corresponding mouse disease models have been developed to simulate the phenotypes observed in clinical patients and investigate their underlying mechanism. Meanwhile, several medications targeting JAK-STAT signaling, including baricitinib and imatinib, have been developed for clinical application, demonstrating significant effects in skeletal disorders such as osteoporosis and osteoarthritis, indicating promising effects in development and abnormalities of dento-maxillofacial. In this review, we aim to summarize the role of JAK-STAT signaling in the development and abnormalities of dento-maxillofacial bone, and the relevant molecules that may be utilized for clinical treatment, to shed new light on the precise treatment of dento-maxillofacial abnormalities.

Advancements in bone organoids: perspectives on construction methodologies and application strategies.

HOXD12 a candidate gene for a novel form of synpolydactyly.

Piezo1 activates Wnt5a/FZD4 signaling to promote osteogenesis and mitigates age-associated bone loss.

Prenatal hydroxychloroquine exposure-induced morphological and functional changes in multiple organs of fetal mice and its characteristics.

A scaffold-free cartilage construct fabricated using a bio 3D printer accelerates critical-size bone defect regeneration.

Biomineralization empowers bone organoids.

Epiphysis is an organized and dynamically evolving developmental tissue that is susceptible to physical damage. At present, significant challenges in developing complex and controllable substitutes for epiphyses persist. In this study, human bone marrow mesenchymal stem cell (hBMSC) microspheres and recombinant human Indian hedgehog (IHH) were used to simulate the key mechanisms of bone development: mesenchymal condensation and biochemical signaling. The results showed that hBMSC microspheres self-assembled into cartilage-like blocks (SAB) under chondrogenic induction. In addition, the ex vivo regulatory effect of recombinant IHH was related to the concentration and treatment time. Notably, 100ng/mL IHH significantly enhanced the chondrogenic differentiation efficiency of hBMSC microspheres while shortening the induction period. The internal cells of SAB-100 were in a dynamic balance of proliferation and differentiation, and its matrix morphology was similar to those of natural epiphyses. Therefore, SAB-100 was regarded as a biomimetic epiphysis (BME). In a large-scale epiphyseal defect model, SAB-100 showed superior chondrocyte regeneration potential. Additionally, elevated thrombospondin-2 (THBS2) expression significantly suppressed angiogenesis and bone bridge formation at the defect site, while partially restoring the cellular and matrix homeostasis of adjacent undamaged epiphyses. Ultimately, SAB-100 effectively prevented angular deformities and reduced limb length discrepancies. These findings suggest that exogenous IHH has the potential to reconstruct the IHH regulatory network ex vivo, and SAB-100 is expected to partially restore the developmental function of damaged epiphyses.

The growth plate and articular cartilage are essential for children's bone development. Precise segmentation of cartilage in MRI images enables the extraction of quantitative indicators for health assessment and risk identification. Therefore, developing high-precision automatic segmentation models is of great importance for monitoring cartilage development and enabling early intervention. However, in pediatric knee joint MRI images, there are significant variations in the size and shape of the cartilage, the cartilage's gray value is close to that of the surrounding tissue or synovial fluid, and the boundaries are often fuzzy. To address these challenges, this paper proposes a new UNet++-based segmentation model, BDU-Net. In this model, an edge-preserving enhancement module (EPEM) is designed based on ordinary differential equations (ODE), with the Runge-Kutta second-order (RK2) method introduced to model and strengthen complex textures and contour regions. The edge perception ability is further improved through dynamic feature-weighted fusion. In addition, a multi-scale feature extraction module(MSFEM) is integrated into the bridge section to enhance the joint modeling of global context and local details, thereby improving the model's ability to focus on and represent key regions. Experiments on three pediatric knee cartilage datasets (PC, MCC, LCGP) demonstrate that BDU-Net outperforms existing state-of-the-art methods in segmentation accuracy, edge preservation, and noise suppression. The proposed method achieves IoU values of 0.7519, 0.8283, and 0.8485 on the three datasets, while the best results from the compared methods are 0.7456, 0.8184, and 0.8352. It also achieves strong results in qualitative analysis and expert scoring, showing clear performance advantages and application potential.

Osteofibrous dysplasia (OFD) is a skeletal RASopathy presenting with periosteal bone lesions that may progress to fracture and delayed healing (pseudarthrosis). MET gene mutations reducing ubiquitin-mediated protein degradation via loss of the juxtamembrane domain (METΔJMD) were previously identified in OFD patients, resulting in ligand-dependent gain-of-function. The impact of METΔJMD expression on skeletal progenitor cell differentiation and the potential efficacy of targeted therapies remain unclear. We engineered MetΔJMD mice and showed that MetΔJMD expression inhibited osteogenic differentiation of skeletal progenitor cells in vitro and impaired cortical bone development and reduced bone stiffness in vivo. In contrast, conditional deletion of Met enhanced osteogenic differentiation of periosteal progenitor cells. Inhibition of MAPK signaling with MEK inhibitors restored osteogenic differentiation of mouse MetΔJMD skeletal progenitor cells and promoted activation of transcriptional signatures associated with skeletal development and osteoblast differentiation in OFD patient pseudarthrosis-derived primary cells. With this preclinical support, we treated with the MEK inhibitor mirdametinib a pediatric OFD patient suffering from a 3-year history of persistent pseudarthrosis, resulting in fracture union. Our findings demonstrate a bi-directional role for MET in regulating osteogenic differentiation of skeletal progenitor cells and a therapeutic avenue to improve clinical outcomes for this, and potential other, skeletal RASopathies. .

Pediatric dogs are predisposed to skeletal disorders during growth, with rickets, hypertrophic osteopathy, and nutritional secondary hyperparathyroidism being the most common. Rickets, usually caused by vitamin D deficiency, leads to bone softening and deformities, whereas hypertrophic osteopathy involves abnormal calcium salt deposition that impairs mobility. This study investigated developmental orthopedic diseases in Aksaray Malakli dogs, focusing on nutritional factors and biochemical markers. Twenty-two pediatric dogs were examined and divided into two groups. Group I (n=11) showed gait abnormalities and postural deformities, whereas Group II (n=11) included clinically healthy dogs. Clinical, radiographic, and biochemical assessments were performed, including cortical index, parathormone, osteocalcin, vitamin D3, calcium, and phosphorus measurements. Nutritional history revealed that Group I dogs were fed exclusively with “yal,” a grain-based diet, likely leading to calcium deficiency and impaired skeletal development. Group II received a balanced diet including animal-based products and commercial feed. Clinical examinations indicated no pain in either group, but Group I showed abnormal posture and forelimb curvature. Radiographs revealed bone structural changes in Group I, while Group II maintained normal alignment. Biochemical tests demonstrated imbalances in Group I, particularly in vitamin D and phosphorus levels, and statistical analysis confirmed significant intergroup differences. These findings indicate that nutrition, vitamin D status, and calciumphosphorus balance are key contributors to metabolic bone disorders in Malakli dogs. Proper nutritional regulation during early growth may help prevent rickets and other metabolic bone diseases in this breed.

Skeletal stem cells (SSCs) and their lineage derivatives play essential roles in bone development, maintenance, and regeneration. In addition to their physiological functions, SSCs have been implicated in primary bone tumor development and bone metastasis. Recent lineage-tracing studies have identified fibroblast growth factor receptor 3 (Fgfr3)-positive endosteal stem cells as a distinct SSC population residing along the endosteal surface of juvenile long bones. This review comprehensively synthesizes previous studies on skeletal stem cells and their lineage derivatives, integrating findings from lineage-tracing approaches, genetically engineered mouse models, and bone tumor models. By organizing current knowledge of SSC hierarchy and differentiation, we provide a framework for understanding how SSC-derived lineages contribute to both bone homeostasis and cancer-related processes. Fgfr3+ endosteal stem cells give rise to osteoblasts and C-X-C motif chemokine ligand 12 (Cxcl12)-positive bone marrow reticular stromal cells that organize the hematopoietic niche. In temporally controlled Fgfr3-creER; Trp53fl/fl models, Trp53 deletion within the endosteal stem cell niche rapidly induces high-penetrance osteosarcoma, indicating that this niche is particularly vulnerable to malignant transformation. Beyond tumor initiation, SSC-derived Cxcl12-expressing stromal cells differentiate into cancer-associated fibroblasts that promote metastatic colonization, angiogenesis, and immunosuppression in bone. Collectively, these findings highlight Fgfr3+ endosteal stem cells as candidate cells of origin for osteosarcoma and underscore the dual role of SSC-derived lineages in both tumor initiation and progression. Targeting SSC-derived endosteal niches may provide new therapeutic opportunities for bone malignancies.

The lemur tree frog (Agalychnis lemur), a critically endangered species, can benefit from ex situ conservation programs; however, managing amphibians under human care presents challenges, including the provision of appropriate nutrition. House crickets (Acheta domesticus), a common feeder insect, have an inverse calcium to phosphorus ratio (Ca:P; 0.15:1) and low calcium content (<0.3%). While gut-loading crickets with an 8% calcium diet can improve their calcium concentrations, no study has assessed the effects of dietary calcium on bone development in Agalychnis spp. Moreover, no study has examined how diet impacts the gut-skin axis and skin microbiome of these frogs. This study examined how crickets gut-loaded with either a 1.3% or 8% calcium diet affected lemur tree frog bone density and skin microbiome. We hypothesized that frogs consuming the 8% calcium diet would exhibit significantly higher Hounsfield units (HU; bone density) over time, as measured by micro-computed tomography (mCT), and that dietary calcium concentration would have no effect on skin bacterial and fungi microbiomes. Eleven juvenile lemur tree frogs underwent mCT scans at baseline and 90 and 180 days. Total body volume of interest analysis showed a significant increase in HU in the 8% calcium group compared to the 1.3% group (F = 9.9, p = 0.01). There was no significant difference noted in the alpha or beta diversities for the bacterial and fungal microbiomes between dietary groups. This study provides the first evidence of dietary calcium's impact on bone density in lemur tree frogs, offering valuable insights for improving ex situ management of this species.

The inward-rectifier potassium channel (Kir) 2.x family is an important family of ion channels in the context of human health. These potassium channels are involved in processes such as cardiac action potential, formation of skeletal muscle, bone development, vasodilation, and neuronal activity and are expressed centrally and peripherally. Given their importance, they are an attractive target for the development of tool compounds. The high homology between the members of the Kir family has made isoform selectivity challenging. In an effort to discover novel chemical matter related to this intriguing target, we performed a high-throughput screen utilizing compounds from the Vanderbilt Institute of Chemical Biology Discovery Collection. This screen of over 20,000 compounds resulted in 48 verified hits consisting of six novel chemical scaffolds. Of these hits, VU0523203 and VU0606851 were selected as promising starting points for initial medicinal chemistry optimization to improve potency and distribution, metabolism, and pharmacokinetic (DMPK) properties. These efforts resulted in the discovery of VU6073995, a compound with modest potency at Kir2.1 and improved DMPK properties compared with ML133.

The RUS-CHN method, part of the China-05 standard, is widely used in China. However, its performance may vary across regions due to socioeconomic and nutritional factors. This study aimed to clinically validate the RUS-CHN method against the Greulich-Pyle (G-P) atlas in a cohort from the developed Suzhou region. We conducted a cross-sectional study of 271 children. Left-hand radiographs were independently assessed by two experienced raters using both the G-P and RUS-CHN methods. Statistical analyses compared the distributions, correlations, and specific bone scores derived from the two methods. The median age of the 271 enrolled children was 12.08years, with a mean height of 155.9 ± 7.4cm and a median BMI of 19.4. Compared to the G-P method, the RUS-CHN method yielded a more concentrated bone age distribution with a smaller interquartile range. Based on the absolute value of Spearman's correlation coefficient, in the overall cohort, the radial score showed the highest correlation with the total RUS-CHN bone age for boys (0.661), followed by the first metacarpal (0.652) and the proximal phalanx of the first finger (0.646). For girls, the third metacarpal score correlated most strongly (0.698), followed by the proximal phalanx of the third finger (0.660) and the proximal phalanx of the fifth finger (0.659). According to the G-P method, 119 children (43.91%) had normal development, 7 (2.58%) were delayed, and 145 (53.51%) were advanced. In contrast, the RUS-CHN method classified 92 children (33.95%) as normal, 4 (1.48%) as delayed, and 175 (64.58%) as advanced. Over 60% of children exhibited advanced bone development, with girls comprising more than half of this group. Children with advanced development had a lower median visit age (11.2years) and a higher BMI than those with normal or delayed development. In the normal development group, for boys, the first metacarpal score showed the highest correlation with RUS-CHN bone age (0.727), followed by the radius (0.709) and the proximal phalanx of the third finger (0.706). For girls in this group, the third metacarpal score correlated highest (0.787), followed by the fifth metacarpal (0.741) and the middle phalanx of the third finger (0.684). In the advanced development group, for boys, the proximal phalanx of the first finger had the highest correlation (0.654), followed by the first metacarpal (0.649) and the radius (0.647). For advanced girls, the proximal phalanx of the fifth finger correlated most strongly (0.684), followed by the proximal phalanx of the third finger (0.661) and the third metacarpal (0.651). The RUS-CHN scoring method is applicable for bone age assessment in children from the Suzhou region. Likely influenced by socioeconomic factors, over 60% of the children in this region were classified as having advanced bone development. Within this scoring system, the evaluation weight of different bones varies by gender and developmental status. Focusing on the maturity of key correlating bones may be more critical for identifying developmental abnormalities.

Protein-rich byproducts from food processing serve as promising sources for the generation of bioactive peptides with health-promoting properties, including the regulation of osteoblast proliferation and bone formation. Defatted egg yolk powder, a nutrient-dense natural matrix, is rich in bioactive precursors. However, the high phosphorylation and compact tertiary structure of its constituent proteins hinder the efficient release of osteogenic peptides. Here, we developed a thermal-enzymatic approach to efficiently produce hydrolyzed egg yolk peptide (YPEP) with enhanced bone-anabolic activity. YPEP enhanced bone development in adolescent models by activating osteoblasts, driving longitudinal growth, and improving trabecular microstructure. Proteomic profiling identified an osteogenic peptide, namely FRTPPFGGF (FR9), which targets the epidermal growth factor receptor (EGFR). FR9 markedly enhanced the proliferation and differentiation of murine MC3T3-E1 preosteoblasts. These findings underscore the osteogenic potential of YPEP and suggest the use of FR9 as a promising functional ingredient for promoting bone development during adolescence.