Potential therapeutic role of spermine via Rac1 in osteoporosis: Insights from zebrafish and mice.

Osteoporosis is a prevalent metabolic bone disease. While drug therapy is essential to prevent bone loss in osteoporotic patients, current treatments are limited by side effects and high costs, necessitating the development of more effective and safer targeted therapies. Utilizing a zebrafish ( Danio rerio) larval model of osteoporosis, we explored the influence of the metabolite spermine on bone homeostasis. Results showed that spermine exhibited dual activity in osteoporotic zebrafish larvae by increasing bone formation and decreasing bone resorption. Spermine not only demonstrated excellent biosafety but also mitigated prednisolone-induced embryonic neurotoxicity and cardiotoxicity. Notably, spermine showcased protective attributes in the nervous systems of both zebrafish embryos and larvae. At the molecular level, Rac1 was identified as playing a pivotal role in mediating the anti-osteoporotic effects of spermine, with P53 potentially acting downstream of Rac1. These findings were confirmed using mouse ( Mus musculus) models, in which spermine not only ameliorated osteoporosis but also promoted bone formation and mineralization under healthy conditions, suggesting strong potential as a bone-strengthening agent. This study underscores the beneficial role of spermine in osteoporotic bone homeostasis and skeletal system development, highlighting pivotal molecular mediators. Given their efficacy and safety, human endogenous metabolites like spermine are promising candidates for new anti-osteoporotic drug development and daily bone-fortifying agents.

Decellularized periosteum promotes guided bone regeneration via manipulation of macrophage polarization.

Periosteum has shown potential as an effective barrier membrane for guided bone regeneration (GBR). However, if recognized as a "foreign body," insertion of a barrier membrane in GBR treatment will inevitably alter the local immune microenvironment and subsequently influence bone regeneration. The aim of this investigation was to fabricate decellularized periosteum (DP) and investigate its immunomodulatory properties in GBR. DP was successfully fabricated from periosteum from the mini-pig cranium. In vitro experiments indicated that the DP scaffold modulated macrophage polarization toward a pro-regenerative M2 phenotype, which in turn facilitated migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. A rat GBR model with a cranial critical-size defect was established, and our in vivo experiment confirmed the beneficial effects of DP on the local immune microenvironment and bone regeneration. Collectively, the findings of this study indicate that the prepared DP possesses immunomodulatory properties and represents a promising barrier membrane for GBR procedures.

Low-dose arecoline regulates distinct core signaling pathways in oral submucous fibrosis and oral squamous cell carcinoma.

BACKGROUND: Betel nut chewing plays a role in the pathogenesis of oral submucous fibrosis (OSF) and oral squamous cell carcinoma (OSCC). As the major active ingredient of the betel nut, the effect of arecoline and its underlying mechanism to OSF and OSCC pathogenesis remain unclear. METHODS: Next-generation sequencing-based transcriptome and dRRBS analysis were performed on OSF and OSCC cells under low-dose arecoline exposure. Functional analyses were performed to compare the different roles of arecoline during OSF and OSCC pathogenesis, and key genes were identified. RESULTS: In this study, we identified that low-dose arecoline promoted cell proliferation of both NFs and OSCC cells via the acceleration of cell cycle progression, while high-dose arecoline was cytotoxic to both NFs and OSCC cells. We performed for the first time the transcriptome and methylome landscapes of NFs and OSCC cells under low-dose arecoline exposure. We found distinct transcriptome and methylome profiles mediated by low-dose arecoline in OSF and OSCC cells, as well as specific genes and signaling pathways associated with metabolic disorders induced by low-dose arecoline exposure. Additionally, low-dose arecoline displayed different functions at different stages, participating in the modulation of the extracellular matrix via Wnt signaling in NFs and epigenetic regulation in OSCC cells. After exposure to low-dose arecoline, the node roles of FMOD in NFs and histone gene clusters in OSCC cells were found. Meanwhile, some key methylated genes induced by arecoline were also identified, like PTPRM and FOXD3 in NFs, SALL3 and IRF8 in OSCC cells, indicating early molecular events mediated by arecoline during OSF and OSCC pathogenesis. CONCLUSIONS: This study elucidated the contribution of low-dose arecoline to OSF and OSCC pathogenesis and identified key molecular events that could be targeted for further functional studies and their potential as biomarkers.

A c-MET-Targeted Topical Fluorescent Probe cMBP-ICG Improves Oral Squamous Cell Carcinoma Detection in Humans.

INTRODUCTION: The postoperative survival of oral squamous cell carcinoma (SCC) relies on precise detection and complete resection of original tumors. The mucosal extension of the tumor is evaluated visually during surgery, but small and flat foci are difficult to detect. Real-time fluorescence imaging may improve detection of tumor margins. MATERIALS AND METHODS: In the current study, a peptide-based near-infrared (NIR) fluorescence dye, c-MET-binding peptide-indocyanine green (cMBP-ICG), which specifically targets tumor via c-MET binding, was synthetized. A prospective pilot clinical trial then was conducted with oral SCC patients and intraoperatively to assess the feasibility of cMBP-ICG used to detect tumors margins. Fluorescence was histologically correlated to determine sensitivity and specificity. RESULTS: The immunohistochemistry (IHC) results demonstrated increased c-Met expression in oral SCC compared with normal mucosa. Tumor-to-background ratios ranged from 2.71 ± 0.7 to 3.11 ± 1.2 in different concentration groups. From 10 patients with oral SCC, 60 specimens were collected from tumor margins. The sensitivity and specificity of discriminative value derived from cMBP-ICG application in humans were respectively 100% and 75%. CONCLUSIONS: Topical application of cMBP-ICG is feasible and safe for optimizing intraoperative visualization and tumor margin detection in oral SCC patients, which could clinically increase the probability of complete resections and improve oncologic outcomes.

Strontium-incorporated bioceramic scaffolds for enhanced osteoporosis bone regeneration.

The restoration of bone defects caused by osteoporosis remains a challenge for surgeons. Strontium ranelate has been applied in preventative treatment approaches due to the biological functions of the trace element strontium (Sr). In this study, we aimed to fabricate bioactive scaffolds through Sr incorporation based on our previously developed modified amino-functional mesoporous bioactive glass (MBG) and to systematically investigate the bioactivity of the resulting scaffold in vitro and in vivo in an osteoporotic rat model. The results suggested that Sr-incorporated amino-functional MBG scaffolds possessed favorable biocompatibility. Moreover, with the incorporation of Sr, osteogenic and angiogenic capacities were upregulated in vitro. The in vivo results showed that the Sr-incorporated amino-functional MBG scaffolds achieved better bone regeneration and vessel formation. Furthermore, bioinformatics analysis indicated that the Sr-incorporated amino-functional MBG scaffolds could reduce reactive oxygen species levels in bone marrow mesenchymal stem cells in the osteoporotic model by activating the cAMP/PKA signaling pathway, thus playing an anti-osteoporosis role while promoting osteogenesis. This study demonstrated the feasibility of incorporating trace elements into scaffolds and provided new insights into biomaterial design for facilitating bone regeneration in the treatment of osteoporosis.

Establishment and assessment of rodent models of medication-related osteonecrosis of the jaw (MRONJ).

Medication-related osteonecrosis of the jaw (MRONJ) is primarily associated with administering antiresorptive or antiangiogenic drugs. Despite significant research on MRONJ, its pathogenesis and effective treatments are still not fully understood. Animal models can be used to simulate the pathophysiological features of MRONJ, serving as standardized in vivo experimental platforms to explore the pathogenesis and therapies of MRONJ. Rodent models exhibit excellent effectiveness and high reproducibility in mimicking human MRONJ, but classical methods cannot achieve a complete replica of the pathogenesis of MRONJ. Modified rodent models have been reported with improvements for better mimicking of MRONJ onset in clinic. This review summarizes representative classical and modified rodent models of MRONJ created through various combinations of systemic drug induction and local stimulation and discusses their effectiveness and efficiency. Currently, there is a lack of a unified assessment system for MRONJ models, which hinders a standard definition of MRONJ-like lesions in rodents. Therefore, this review comprehensively summarizes assessment systems based on published peer-review articles, including new approaches in gross observation, histological assessments, radiographic assessments, and serological assessments. This review can serve as a reference for model establishment and evaluation in future preclinical studies on MRONJ.

Trace Element-Augmented Titanium Implant With Targeted Angiogenesis and Enhanced Osseointegration in Osteoporotic Rats.

Deteriorated bone quality in osteoporosis challenges the success of implants, which are in urgent need for better early osseointegration as well as antibacterial property for long-term stability. As osteoporotic bone formation tangles with angiogenic clues, the relationship between osteogenesis and angiogenesis has been a novel therapy target for osteoporosis. However, few designs of implant coatings take the compromised osteoporotic angiogenic microenvironment into consideration. Here, we investigated the angiogenic effects of bioactive strontium ions of different doses in HUVECs only and in a co-culture system with BMSCs. A proper dose of strontium ions (0.2-1 mM) could enhance the secretion of VEGFA and Ang-1 in HUVECs as well as in the co-culture system with BMSCs, exhibiting potential to create an angiogenic microenvironment in the early stage that would be beneficial to osteogenesis. Based on the dose screening, we fabricated a bioactive titanium surface doped with zinc and different doses of strontium by plasma electrolytic oxidation (PEO), for the establishment of a microenvironment favoring osseointegration for osteoporosis. The dual bioactive elements augmented titanium surfaces induced robust osteogenic differentiation, and enhanced antimicrobial properties. Augmented titanium implant surfaces exhibited improved bone formation and bone-implant contact under comprehensive assessment of an in vivo bone-implant interface. In conclusion, zinc- and strontium-augmented titanium surface benefits the osseointegration in osteoporosis via promoting osteogenic differentiation, exerting antibacterial efficacy, and stimulating early angiogenesis.

Apoptosis repressor with caspase recruitment domain (ARC) promotes bone regeneration of bone marrow-derived mesenchymal stem cells by activating Fgf-2/PI3K/Akt signaling.

OBJECTIVES: This study aims to investigate whether apoptosis repressor with caspase recruitment domain (ARC) could promote survival and enhance osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). MATERIALS AND METHODS: The lentivirus transfection method was used to establish ARC-overexpressing BMSCs. The CCK-8 method was used to detect cell proliferation. The BD Pharmingen™ APC Annexin V Apoptosis Detection kit was used to detect cell apoptosis. The osteogenic capacity was investigated by OCN immunofluorescence staining, ALP analysis, ARS assays, and RT-PCR analysis. Cells were seeded into calcium phosphate cement (CPC) scaffolds and then inserted subcutaneously into nude mice and the defect area of the rat calvarium. Histological analysis was conducted to evaluate the in vivo cell apoptosis and new bone formation of the ARC-overexpressing BMSCs. RNA-seq was used to detect the possible mechanism of the effect of ARC on BMSCs. RESULTS: ARC promoted BMSC proliferation and inhibited cell apoptosis. ARC enhanced BMSC osteogenic differentiation in vitro. An in vivo study revealed that ARC can inhibit BMSC apoptosis and increase new bone formation. ARC regulates BMSCs mainly by activating the Fgf-2/PI3K/Akt pathway. CONCLUSIONS: The present study suggests that ARC is a powerful agent for promoting bone regeneration of BMSCs and provides a promising method for bone tissue engineering.

Analysis of clinicopathological characteristics, MYB rearrangement and prognostic factors in salivary adenoid cystic carcinoma.

Recent studies have indicated that a recurrent t(6;9)(q22-23;p23-24) chromosomal translocation in salivary adenoid cystic carcinoma (ACC) results in a MYB proto-oncogene transcription factor-nuclear factor I/B (MYB-NFIB) gene fusion, which has not previously been detected in any non-ACC carcinomas of the head and neck. In the present study, data on clinical factors affecting the survival rate of patients with salivary ACC from a single institution was retrospectively analyzed, and the frequency of MYB gene rearrangement determined. A total of 97 patient cases were analyzed, and young adults presenting with ACC (<40 years old) accounted for 19.6% of all patients (n=19). A total of 70.1% (n=68) displayed neurological symptoms, including pain, paraesthesia, tongue deviation, and facial paralysis. A marked majority of the analyzed tumors (85.6%) displayed evidence of MYB rearrangement. MYB rearrangement was significantly higher in patients with late Tumor-Node-Metastasis (TNM) stage cancer compared with that in patients with early TNM stage (P=0.033), as detected by a dual color MYB break-apart fluorescence in situ hybridization probe. Kaplan-Meier analysis revealed significant differences in patient overall survival (OS) time with regard to age, gender, TNM stage, neurological symptoms, margin status and MYB rearrangement. Specifically, young age was significantly associated with a shorter OS time. In summary, the present study suggested that young patients with salivary ACC presented with a worse prognosis, in contrast to the majority of patients with salivary ACC. Moreover, MYB alterations exhibited a high positive rate in salivary ACC, and therefore, the absence of MYB rearrangements may be associated with a better prognosis.

Biocompatible silk/calcium silicate/sodium alginate composite scaffolds for bone tissue engineering.

Scaffolds are crucial for bone tissue engineering since their compositions and properties could significantly affect the seeded cells' behavior. In this study, we developed an interpenetrating network hydrogel by utilizing Ca2+ from calcium silicate (CS) to simultaneously crosslink silk fibroin (SF) and sodium alginate (SA). Afterwards, the hydrogels were lyophilized to obtain scaffolds and systematically evaluated by physical characterizations, in vitro cytocompatibility and alkaline phosphatase (ALP) assay. We found that CS inside the porous structure of SF/CS/SA scaffolds could remarkably enhance hydrophilicity, degradation, compression resistance, bioactivity and pH of SF/CS/SA scaffolds. Scaffolds with CS concentrations of 25% and 12% (25/CS and 12/CS) could dominantly stimulate proliferation of bone marrow stromal cells (BMSCs). Besides, BMSCs cultured with 25/CS and 12/CS scaffolds showed high ALP activity, respectively. Consequently, this study suggested SF/CS/SA scaffolds possess potential in non-loading bone tissue engineering application.

In vivo and in vitro study of osteogenic potency of endothelin-1 on bone marrow-derived mesenchymal stem cells.

Bone marrow-derived mesenchymal stem cells (BMSCs) are a major source of osteoblasts and are crucial for bone remolding and repair and thus they are widely used for tissue engineering applications. Tissue engineering in combination with gene therapy is considered as a promising approach in new bone regeneration. Endothelin-1（EDN-1）is produced by vascular endothelial cells which plays an important role during bone development. However, its role in BMSCs remains largely unknown. We established EDN-1 overexpressed BMSCs, proliferation ability and osteogenesis differentiation were detected respectively. Transduced BMSCs were then combined with CPC-scaffold to repair calvarial defects in rats to evaluate the in-vivo osteogenic potential of EDN-1. EDN-1 overexpressed BMSCs showed increased proliferation and significantly increased osteogenesis potential ability than vector transfected control. The in-vivo data also revealed more new bone formation with higher bone mineral density and number of trabeculae in EDN-1 overexpressed BMSCs. These findings have demonstrated the influence of EDN-1 on differentiation potential of BMSCs, which suggest that EDN-1 may be a new promising agent for bone tissue engineering.

Primary intraosseous adenoid cystic carcinoma of the mandible: a comprehensive review and analysis of four new cases with emphasis on morphologic, immunophenotypic, and molecular characteristics.

OBJECTIVE: To comprehensively review the clinical manifestations, imaging, diagnosis, treatment, and pathologic features of primary intraosseous adenoid cystic carcinoma (PIACC) of the mandible and analyze PIACC histopathology and molecular features in four cases. STUDY DESIGN: We reviewed the literature and retrospectively studied four cases of PIACC. RESULTS: The clinical and imaging findings of PIACC are similar to other malignant or borderline-malignant mandible tumors. The four cases of PIACC included three males and one female (aged between 41 and 58 years). The histopathologic features of the tumors resembled those of ACC. We observed abundant osteoclasts resorbing bone at the leading edge of the tumors characterized by solid structure histology but not by the cribriform subtype. Additionally, all four cases showed abnormalities in the MYB gene and high expression of MYB protein. All patients survived for the duration of follow-up, and two patients had distant metastases (followed up for 3 to 36 months). CONCLUSIONS: PIACC is extremely rare and is often clinically misdiagnosed. Different histologic subtypes could show different mechanisms of invasion of the mandible. MYB gene and protein expression abnormalities can be used as indicators for the precise diagnosis of PIACC.

MFAP5 and TNNC1: Potential markers for predicting occult cervical lymphatic metastasis and prognosis in early stage tongue cancer.

The purpose of this study is to identify candidate genes that could predict prognosis of early-stage tongue squamous cell carcinoma (TSCC) and its occult cervical lymphatic metastasis by large-scale gene expression profiling. Tumor tissue and matched normal mucosa samples were collected from patients with TSCC and analyzed with Affymetrix HTA2.0 high-density oligonucleotide array. Differentially expressed genes in TSCC with cervical lymph node metastasis (CLNM) were further analyzed with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes for their functions and related pathways. A total of 107 differentially expressed genes (p < 0.05) were identified by microarray in TSCC samples with CLNM (n = 6) compared to those without CLNM (n = 6). Genes involved in the cell-matrix adherens junction and migration function including MFAP5, TNNC1, MGP, FBFBP1 and FBXO32 were selected and validated by RT-PCR in TSCC samples (n = 32). Of the five genes, MFAP5 and TNCC1 expressions were further validated by immohistochemistry (n = 61). The significant positive correlation between MFAP5 and TNNC1 expression (p<0.001) was observed. Notably, over-expression of MFAP5 and TNNC1 were correlated with CLNM, metastasis relapse-free survival and overall survival. Our findings indicated that MFAP5 and TNNC1 may be potential markers for predicting occult cervical lymphatic metastasis and prognosis of oral tongue carcinoma.

Apoptosis repressor with caspase recruitment domain enhances survival and promotes osteogenic differentiation of human osteoblast cells under Zoledronate treatment.

Zoledronate is one of the most potent nitrogen-containing bisphosphonates which has been demonstrated to result in osteoblast apoptosis and impact osteogenic differentiation in vitro. This effect of Zoledronate on osteoblasts may partially explain bisphosphonate­associated osteonecrosis of the jaw, a serious complication associated with treatment with bisphosphonates. Apoptosis repressor with caspase recruitment domain (ARC) is a multifunctional inhibitor of apoptosis that is physiologically expressed predominantly in post­mitotic cells such as cardiomyocytes, neurons and skeletal muscle cells. However, its effect on human osteoblasts remains unclear. The current study aimed to investigate the effects of ARC on human osteoblasts under the treatment of high concentrations of Zoledronate. ARC­overexpressed human osteoblasts were established and were exposed to Zoledronate with different concentrations (0, 1 and 5 µM) in vitro. Cell numbers were detected using the MTT assay, and flow cytometry was used to identity cell apoptosis. Alkaline phosphatase staining, quantitative analysis and ectopic osteogenesis in nude mice were used to evaluate the osteogenic differentiation of ARC­overexpressed osteoblasts. It was observed that ARC is able to reverse the inhibitory effect of Zoldronate on osteoblasts. ARC is additionally able to promote osteogenic differentiation of osteoblasts and inhibit their apoptosis. These observations suggest a critical role for ARC in the regulation of human osteoblasts under Zoledronate treatment.