Bioactive nanocomposite hydrogel enhances postoperative immunotherapy and bone reconstruction for osteosarcoma treatment.

Osteosarcoma, a malignant bone tumor often characterized by high hedgehog signaling activity, residual tumor cells, and substantial bone defects, poses significant challenges to both treatment response and postsurgical recovery. Here, we developed a nanocomposite hydrogel for the sustained co-delivery of bioactive magnesium ions, anti-PD-L1 antibody (αPD-L1), and hedgehog pathway antagonist vismodegib, to eradicate residual tumor cells while promoting bone regeneration post-surgery. In a mouse model of tibia osteosarcoma, this hydrogel-mediated combination therapy led to remarkable tumor growth inhibition and hence increased animal survival by enhancing the activity of tumor-suppressed CD8+ T cells. Meanwhile, the implanted hydrogel improved the microenvironment of osteogenesis through long-term sustained release of Mg2+, facilitating bone defect repair by upregulating the expression of osteogenic genes. After 21 days, the expression levels of ALP, COL1, RUNX2, and BGLAP in the Vis-αPD-L1-Gel group were approximately 4.1, 5.1, 5.5, and 3.4 times higher than those of the control, respectively. We believe that this hydrogel-based combination therapy offers a potentially valuable strategy for treating osteosarcoma and addressing the tumor-related complex bone diseases.

Photothermal switch by gallic acid-calcium grafts synthesized by coordination chemistry for sequential treatment of bone tumor and regeneration.

The residual bone tumor and defects which is caused by surgical therapy of bone tumor is a major and important problem in clinicals. And the sequential treatment for irradiating residual tumor and repairing bone defects has wildly prospects. In this study, we developed a general modification strategy by gallic acid (GA)-assisted coordination chemistry to prepare black calcium-based materials, which combines the sequential photothermal therapy of bone tumor and bone defects. The GA modification endows the materials remarkable photothermal properties. Under the near-infrared (NIR) irradiation with different power densities, the black GA-modified bone matrix (GBM) did not merely display an excellent performance in eliminating bone tumor with high temperature, but showed a facile effect of the mild-heat stimulation to accelerate bone regeneration. GBM can efficiently regulate the microenvironments of bone regeneration in a spatial-temporal manner, including inflammation/immune response, vascularization and osteogenic differentiation. Meanwhile, the integrin/PI3K/Akt signaling pathway of bone marrow mesenchymal stem cells (BMSCs) was revealed to be involved in the effect of osteogenesis induced by the mild-heat stimulation. The outcome of this study not only provides a serial of new multifunctional biomaterials, but also demonstrates a general strategy for designing novel blacked calcium-based biomaterials with great potential for clinical use.

The potent osteo-inductive capacity of bioinspired brown seaweed-derived carbohydrate nanofibrous three-dimensional scaffolds.

This study aimed to investigate the osteo-inductive capacity of a fucoidan polysaccharide network derived from brown algae on human adipose-derived stem cells (HA-MSCs) for bone regeneration. The physiochemical properties of the scaffold including surface morphology, surface chemistry, hydrophilicity, mechanical stiffness, and porosity were thoroughly characterized. Both in vitro and in vivo measurements implied a superior cell viability, proliferation, adhesion, and osteo-inductive performance of obtained scaffolds compared to using specific osteogenic induction medium with increased irregular growth of calcium crystallites, which mimic the structure of natural bones. That scaffold was highly biocompatible and suitable for cell cultures. Various examinations, such as quantification of mineralization, alkaline phosphatase, gene expression, and immunocytochemical staining of pre-osteocyte and bone markers confirmed that HAD-MSCs differentiate into osteoblasts, even without an osteogenic induction medium. This study provides evidence for the positive relationship and synergistic effects between the physical properties of the decellularized seaweed scaffold and the chemical composition of fucoidan in promoting the osteogenic differentiation of HA-MSCs. Altogether, the natural matrices derived from brown seaweed offers a sustainable, cost-effective, non-toxic bioinspired scaffold and holds promise for future clinical applications in orthopedics.

Polydopamine-Based Biomaterials in Orthopedic Therapeutics: Properties, Applications, and Future Perspectives.

Polydopamine is a versatile and modifiable polymer, known for its excellent biocompatibility and adhesiveness. It can also be engineered into a variety of nanoparticles and biomaterials for drug delivery, functional modification, making it an excellent choice to enhance the prevention and treatment of orthopedic diseases. Currently, the application of polydopamine biomaterials in orthopedic disease prevention and treatment is in its early stages, despite some initial achievements. This article aims to review these applications to encourage further development of polydopamine for orthopedic therapeutic needs. We detail the properties of polydopamine and its biomaterial types, highlighting its superior performance in functional modification on nanoparticles and materials. Additionally, we also explore the challenges and future prospects in developing optimal polydopamine biomaterials for clinical use in orthopedic disease prevention and treatment.

Bone marrow mesenchymal stem cells in treatment of peripheral nerve injury.

Peripheral nerve injury (PNI) is a common neurological disorder and complete functional recovery is difficult to achieve. In recent years, bone marrow mesenchymal stem cells (BMSCs) have emerged as ideal seed cells for PNI treatment due to their strong differentiation potential and autologous transplantation ability. This review aims to summarize the molecular mechanisms by which BMSCs mediate nerve repair in PNI. The key mechanisms discussed include the differentiation of BMSCs into multiple types of nerve cells to promote repair of nerve injury. BMSCs also create a microenvironment suitable for neuronal survival and regeneration through the secretion of neurotrophic factors, extracellular matrix molecules, and adhesion molecules. Additionally, BMSCs release pro-angiogenic factors to promote the formation of new blood vessels. They modulate cytokine expression and regulate macrophage polarization, leading to immunomodulation. Furthermore, BMSCs synthesize and release proteins related to myelin sheath formation and axonal regeneration, thereby promoting neuronal repair and regeneration. Moreover, this review explores methods of applying BMSCs in PNI treatment, including direct cell transplantation into the injured neural tissue, implantation of BMSCs into nerve conduits providing support, and the application of genetically modified BMSCs, among others. These findings confirm the potential of BMSCs in treating PNI. However, with the development of this field, it is crucial to address issues related to BMSC therapy, including establishing standards for extracting, identifying, and cultivating BMSCs, as well as selecting application methods for BMSCs in PNI such as direct transplantation, tissue engineering, and genetic engineering. Addressing these issues will help translate current preclinical research results into clinical practice, providing new and effective treatment strategies for patients with PNI.

Comparative assessment of bone cement implantation syndrome in cemented bipolar hemiarthroplasty: impact in patients with and without preexisting heart disease.

Background: With the increasing incidence of hip fractures in older adults, hip replacement with a cemented femoral stem has become a viable treatment option. However, concerns regarding potential complications, particularly bone cement implantation syndrome (BCIS), especially in patients with preexisting medical conditions, have prompted orthopedic surgeons to explore alternative approaches. Objective: The research question of this retrospective study is whether BCIS incidence in patients with preexisting heart disease undergoing cemented bipolar hemiarthroplasty is higher than that of patients without preexisting heart disease. Methods: We retrospectively analyzed data from 311 patients undergoing cemented bipolar hemiarthroplasty, including 188 without preexisting heart disease and 123 with heart disease. Anesthetic records were reviewed to assess parameters related to BCIS. BCIS severity was graded systematically, emphasizing key metrics, such as hypotension, arterial desaturation, and the loss of consciousness. Results: Among the patients, no perioperative deaths occurred. Grade 1 BCIS was observed in 13 patients (4.18 %), without instances of grade 2 or 3. Notably, grade 1 BCIS was observed in only 2 patients with preexisting heart disease (1.63%) and 11 patients (5.85%) without preexisting heart disease. Conclusion: BCIS incidence after cemented bipolar hemiarthroplasty was minimal, with a predominantly low severity. Importantly, preexisting heart disease did not pose a significant increase in the risk of BCIS. This finding confirms the safety of cemented bipolar hemiarthroplasty in older adults. Level of Evidence: III.

Potential plausible role of Wharton's jelly mesenchymal stem cells for diabetic bone regeneration.

This letter addresses the review titled "Wharton's jelly mesenchymal stem cells: Future regenerative medicine for clinical applications in mitigation of radiation injury". The review highlights the regenerative potential of Wharton's jelly mesenchymal stem cells (WJ-MSCs) and describes why WJ-MSCs will become one of the most probable stem cells for future regenerative medicine. The potential plausible role of WJ-MSCs for diabetic bone regeneration should be noticeable, which will provide a new strategy for improving bone regeneration under diabetic conditions.

Simple Bone Cyst Within Florid Cemento-Osseous Dysplasia: A Report of Two Cases.

Florid cemento-osseous dysplasia (FCOD) can rarely be associated with bone lesions, including simple bone cysts (SBCs). Only a few cases showing the co-occurrence of these two distinct entities have been reported in the literature. This article reports two new cases of SBCs within FCOD. The first case involves a 37-year-old Black female with a large radiolucent lesion around the apex of the right third mandibular molar, accompanied by multiple cemento-osseous lesions around the mandibular teeth. Surgical exploration revealed an empty bone cavity, confirming the diagnosis of an SBC. Curettage of the bone walls was performed to stimulate healing, with promising results observed at the nine-month follow-up. The second case concerns a 44-year-old Black female presenting with a radiolucent lesion at the site of extraction of the left third mandibular molar and a slightly painful radiolucent/radio-opaque lesion in the apical region of the right first mandibular molar. Surgical exploration confirmed an SBC in the region of the left third mandibular molar and a bone biopsy was made. Histopathological analysis confirmed FCOD. Curettage of the bone wall was again used to promote healing through increased bleeding. At the 30-month follow-up, new dysplastic lesions had appeared, the initial SBC had healed completely, and a new SBC seemed to have developed in the apical region of the left second mandibular premolar. These cases highlight the importance of considering SBCs in the differential diagnosis of well-defined radiolucent lesions and demonstrate that surgical intervention for SBC-associated FCOD can yield favorable outcomes. From these cases, we learn the critical need for accurate diagnosis to avoid unnecessary treatments and the value of regular follow-up to monitor for recurrence or new lesions.

Assessing the Effect of Exogenous Melatonin on Orthodontic Tooth Movement.

OBJECTIVE: To examine the effect of orthodontic tooth movement on experimental Wistar rats by synthesizing melatonin formulation for administration and conducting serological analysis of alkaline phosphatase (ALP) and melatonin, along with histological evaluation and immunohistochemistry analysis of ALP and interleukin-6 (IL-6) in both control and experimental groups. METHODOLOGY: Nine male Wistar rats were randomly divided into negative (n = 3), positive control (n = 3), and experimental groups (n = 3). Endogenous melatonin levels (pg/mL) were assessed, and an orthodontic force of 10 cN was applied to positive control and experimental groups using a ligature wire. The experimental group received a daily dose of 10 mg/kg melatonin via intraperitoneal injection. After eight weeks, blood samples and radiographs were collected, and mandible sections were prepared for histopathological and immunohistochemical evaluation. RESULTS: The radiographic evaluation shows minimal orthodontically induced tooth movement in comparison to the positive control group. In serological analysis, ALP was found to be increased in rats under the melatonin group. And, in the immunohistochemical evaluation, ALP was found to be increased in the melatonin group, whereas IL-6 was found to be decreased in the same (P = 0.027). CONCLUSIONS: The study elucidates that the administration of exogenous melatonin during orthodontic tooth movement in Wistar rats induces bone formation and inhibits resorption, eventually decelerating the process of orthodontic tooth movement. Our study emphasizes melatonin's dualistic role in stimulating bone production and suppressing resorption, offering potential therapeutic clinical implications in orthodontics.

Variational Autoencoders for Generative Drug-Gene Interactions in Periodontal Bone Resorption.

Introduction Periodontal bone resorption is a significant dental problem causing tooth loss and impaired oral function. It is influenced by factors such as bacterial plaque, genetic predisposition, smoking, systemic diseases, medications, hormonal changes, and poor oral hygiene. This condition disrupts bone remodeling, favoring resorptive processes. Variational autoencoders (VAEs) can learn the distribution of drug-gene interactions from existing data, identify potential drug targets, and predict therapeutic effects. This study investigates the generation of drug-gene interactions in periodontal bone resorption using VAEs. Methods A bone resorptive drugs dataset was retrieved from Probes and Drugs and analyzed using Cytoscape (https://cytoscape.org/) and CytoHubba (https://apps.cytoscape.org/apps/cytohubba), powerful tools for studying drug-gene interactions in bone resorption. The dataset was then prepared for matrix representation, with normalized input data. It was subsequently divided into training, validation, and testing sets. We then built an encoder-decoder network, defined a loss function, optimized parameters, and fine-tuned hyperparameters. Using VAEs, we generated new drug-gene interactions, assessed model performance, and visualized the latent space with reconstructed drug-gene interactions for further insights. Results The analysis revealed the top hub genes in drug-gene interactions, including Matrix Metalloproteinase (MMP) 14, MMP 9, HIF1A, STAT1, MAPT, CAS9, MMP2, CASP3, MMP1, and MAK1. The VAE's reconstruction accuracy was measured using mean squared error (MSE), with an average squared difference of 0.077. Additionally, the KL divergence value was 2.349, and the average reconstruction log-likelihood was -246. Conclusion The generative variational encoder model for drug-gene interactions in bone resorption demonstrates high accuracy and reliability in representing complex drug-gene relationships within this context.

Uncommon Presentation of Solitary Plasmacytoma in the Nasal Cavity: Diagnostic and Therapeutic Challenges.

Extramedullary solitary plasmacytoma (SP) is an uncommon tumor and is even rare in the head and neck locations. Here, we report the case of an 82-year-old man admitted to our department for the management of nasal cavity SP. Radiological investigation showed a locally advanced tumor making the patient a non-candidate for surgery. The patient had undergone radiotherapy alone to a total dose of 50 Gy, with 2 Gy per fraction five days a week. After a follow-up of nine months, the tumor recurred, and the patient was managed in the internal medicine department. He received palliative chemotherapy with the cyclophosphamide, dexamethasone, and thalidomide protocol which resulted in a good response. This case illustrates the diagnostic challenges and treatment complexities of SP, particularly in rare locations such as the nasal cavity.

Association between nonalcoholic fatty liver disease and bone mineral density: Mendelian randomization and mediation analysis.

Background: Observational studies have reported significant association between non-alcoholic fatty liver disease (NAFLD) and bone mineral density (BMD), a critical indicator of bone health. We aimed to investigate whether NAFLD is a cause for changes in BMD. Methods: We selected 29 independent SNPs as instrumental variables for NAFLD. A range of Mendelian randomization (MR) methods, namely the inverse variance-weighted (IVW) method, weighted-median, weighted-mode, and MR-Egger regression, were utilized to determine the causal effects of NAFLD on BMD. Two-step MR analysis was conducted to determine the mediating effect of fasting glucose, insulin, glycosylated hemoglobin, low-density cholesterol, and body-mass index on the association between NAFLD and BMD. False-discovery-rate (FDR) was used to correct for multiple testing bias. Results: The IVW-method indicated a significantly inverse association between genetically predicted NAFLD and total body BMD (ß = -0.04, 95 % CI -0.07 to -0.02, FDR = 0.010). Notably, the relationship was more pronounced in participants over 60 years of age (ß = -0.06, 95 % CI -0.11 to -0.02, FDR = 0.030). Inverse associations were observed in other subpopulations and in site-specific BMD, though they were not statistically significant after correcting for multiple testing. We observed a significantly positive association between NAFLD and the risk of osteoporosis. Consistency in results was observed across multiple MR methods and in the repeated analysis. Fasting glucose, insulin, and glycosylated hemoglobin mediated 25.4 % (95 % CI 17.6-31.5 %), 18.9 % (12.0-24.9 %), and 27.9 % (19.9-36.7 %) of the effect of NAFLD on BMD, respectively. Conclusion: Our findings underscore a probable causal negative link between NAFLD and BMD, indicating that NAFLD might detrimentally affect bone health, especially in older individuals.

Advances in magnesium-containing bioceramics for bone repair.

Reconstruction of bone defects or fractures caused by ageing, trauma and tumour resection is still a great challenge in clinical treatment. Although autologous bone graft is considered as gold standard, the source of natural bone is limited. In recent years, regenerative therapy based on bioactive materials has been proposed for bone reconstruction. Specially, numerous studies have indicated that bioactive ceramics including silicate and phosphate bioceramics exhibit excellent osteoinductivity and osteoconductivity, further promote bone regeneration. In addition, magnesium (Mg) element, as an indispensable mineral element, plays a vital role in promoting bone mineralisation and formation. In this review, different types of Mg-containing bioceramics including Mg-containing calcium phosphate-based bioceramics (such as Mg-hydroxyapatite, Mg-biphasic calcium phosphate), Mg-containing calcium silicate-based bioceramics (such as Mg2SiO4, Ca2MgSi2O7 and Mg-doped bioglass), Mg-based biocements, Mg-containing metal/polymer-bioceramic composites were systematacially summarised. Additionally, the fabrication technologies and their materiobiological effects were deeply discussed. Clinical applications and perspectives of magnesium-containing bioceramics for bone repair are highlighted. Overall, Mg-containing bioceramics are regarded as regenerative therapy with their optimised performance. Furthermore, more in-depth two-way researches on their performance and structure are essential to satisfy their clinical needs.

Meticulously engineered three-dimensional-printed scaffold with microarchitecture and controlled peptide release for enhanced bone regeneration.

The repair of large load-bearing bone defects requires superior mechanical strength, a feat that a single hydrogel scaffold cannot achieve. The objective is to seamlessly integrate optimal microarchitecture, mechanical robustness, vascularisation, and osteoinductive biological responses to effectively address these critical load-bearing bone defects. To confront this challenge, three-dimensional (3D) printing technology was employed to prepare a polycaprolactone (PCL)-based integrated scaffold. Within the voids of 3D printed PCL scaffold, a methacrylate gelatin (GelMA)/methacrylated silk fibroin (SFMA) composite hydrogel incorporated with parathyroid hormone (PTH) peptide-loaded mesoporous silica nanoparticles (PTH@MSNs) was embedded, evolving into a porous PTH@MSNs/GelMA/SFMA/PCL (PM@GS/PCL) scaffold. The feasibility of fabricating this functional scaffold with a customised hierarchical structure was confirmed through meticulous chemical and physical characterisation. Compression testing unveiled an impressive strength of 17.81 ± 0.83 MPa for the composite scaffold. Additionally, in vitro angiogenesis potential of PM@GS/PCL scaffold was evaluated through Transwell and tube formation assays using human umbilical vein endothelium, revealing the superior cell migration and tube network formation. The alizarin red and alkaline phosphatase staining assays using bone marrow-derived mesenchymal stem cells clearly illustrated robust osteogenic differentiation properties within this scaffold. Furthermore, the bone repair potential of the scaffold was investigated on a rat femoral defect model using micro-computed tomography and histological examination, demonstrating enhanced osteogenic and angiogenic performance. This study presents a promising strategy for fabricating a microenvironment-matched composite scaffold for bone tissue engineering, providing a potential solution for effective bone defect repair.

Intraosseous pneumatocyst of the scapula: A case report.

Intraosseous pneumatocysts are benign, gas-filled cystic structures of bone, typically asymptomatic and discovered incidentally on imaging. Their precise aetiology remains unclear, with the prevailing hypothesis being that they result from air accumulation within the bone due to a vacuum phenomenon, typically linked to an adjacent joint space or intervertebral disc. We report the case of a 37-year-old man with an incidental intraosseous pneumatocyst of the scapula, which was evaluated with CT and MRI. Using thin-slice CT, we are able to detect a tiny cortical breach suggestive of a communication between the lesion and the adjacent glenohumeral joint, lending support to the aforementioned aetiological hypothesis.

Middle-aged women with hematodiaphyseal dysplasia: Ghosal syndrome: Case report.

Ghosal hematodiaphyseal dysplasia (GHDD) is a rare autosomal recessive disorder characterized by increased bone density involving diaphyses of long bones and defective hematopoiesis. It is due to biallelic variants in the TBXAS1 (OMIM*274180) gene, which encodes for thromboxane synthase. We present a rare case of a middle-aged woman who presented with chronic anemia and bone pain. About 31-year-old Southeast Asian female with a history of persistent iron deficiency anemia (6.1 gm/dL) presents with bilateral knee pain for 4 years. Autoimmune panel turned out to be negative. CT scan of the lower limbs showed multilamellated endosteal thickening specifically involving diaphyses with severe narrowing of medullary canal. PET CT scan revealed tubular remodeling, intramedullary ground glass matrix, and mild cortical thickening with increased FDG uptake in diaphyseal regions of femur and tibia. Bone marrow biopsy of left tibia revealed fibrocellular marrow with dyserythropoiesis. Considering the slow progression of illness over 4 years and radiological evidence suggestive of bone remodeling with severe narrowing of medullary canal as the cause of anemia, the patient underwent molecular analysis for GHDD. Results revealed homozygous p.Arg412Gln (exon 11) in TBXAS1 gene. Considering the effect of NSAIDs on cyclooxygenase and its downstream metabolites, oral Aspirin 150 mg/day was initiated. Hemoglobin improved to 11 gm/dL at 3-month follow-up visit. The complexity of reaching a diagnosis of GHDD underscores the importance of maintaining a high clinical suspicion and thorough analysis of radiological evidence. The treatment for GHDD involves aspirin, a readily available drug.

Osteoid osteoma of third metatarsal bone treated with radiofrequency ablation: Case report, imaging findings and review of the literature.

Osteoid Osteoma (OO) is a frequent benign bone tumor that commonly affects males between 5 and 25. It usually arises from appendicular skeleton involving typically femur and tibia. OOs arising from small bones of hands and feet are very uncommon and metatarsal lesions account for only 1.7%. We report a case of a 20 year-old boy with a long history of nocturnal left foot pain with a good clinical response to assumption of salicylates or nonsteroidal anti-inflammatory drugs (NSAIDs). Plain radiograph of his left showed unconclusive results. Therefore, he underwent a contrast enhanced CT (CECT) scan with multiplanar reconstruction (MPR) that showed a bony lesion in the left third metatarsal bone that was compatible with a nidus even in absence of clear peri-nidal sclerosis. Therefore, other ancillary techniques such as MRI and bone scintigraphy were performed. Conclusive diagnosis was OO of third left metatarsal bone. Our patient underwent a mini-invasive treatment with radiofrequency (RF) ablation. After recovery, our patient had no post-operative complications and showed optimal clinical conditions with complete remission of left foot pain and no change or impairment in walking. In this essay, we discuss key imaging findings of OO of small bones and its treatment with radiofrequency ablation. We describe method of execution and illustrate advantages of this mini-invasive technique. We also perform a review of the literature.

Impacts of people at-risk of either cow milk allergies or lactose intolerance on their daily calcium intake and bone mineral density.

Background: People who are at risk of either cow milk allergies or lactose intolerance may need to avoid consuming milk and milk products, which are well-known abundant sources of calcium (Ca). This limitation in calcium intake could affect bone health. Currently, there is limited knowledge on the impact of avoiding the consumption of milk and milk products on the daily Ca intake and bone mineral density (BMD) of people at risk of cow milk allergies. This study aimed to investigate the differences between the amount of Ca intake and BMD values between people who are at risk of cow milk allergies and those who are not. Methods: A total of 80 participants were recruited, and further divided into two groups, the at-risk cow milk allergies (AR) group (n = 40) and the normal (NOR) group, using the cow milk allergies and lactose intolerance screening questionnaire. The anthropometric assessment, body composition analyses, 3-day dietary record, and bone mass density (wrist and ankle bones) measurement of all participants were collected using the dual x-ray absorptiometry (DEXA) technique to compare the differences of variables between the two groups. Results: The participants in the AR group presented a significantly lower amount of Ca intake (317 mg/day) than those in the NOR group (623 mg/day) (p < 0.05). The bone mineral density (BMD) parameters indicated that the NOR group presented significantly higher T-scores and BMD values of the wrist (T-score = -0.27 and BMD = 0.57 g/cm2) and ankle (T-score = -0.01 and BMD = 0.59 g/cm2) bones when compared with the AR group (T-score = -1.96 and BMD = 0.48 g/cm2 for the wrist bone, and T-score = -1.18 and BMD = 0.47 g/cm2 for the ankle bone) (p < 0.05). In addition, the results indicated significantly positive correlations between the amount of Ca intake and the T-scores and BMD values of both the wrist and ankle bones among all participants (p < 0.05). Conclusion: In this responding sample, participants at risk of cow milk allergies experienced a significantly negative impact on the amount of Ca intake and BMD values. Professionals in nutrition and dietetics should provide nutrition education and strategies that can enhance the Ca intake among this population to help them meet the daily Ca intake recommendation, ultimately leading to better bone health.

Optimizing silicon doping levels for enhanced osteogenic and angiogenic properties of 3D-printed biphasic calcium phosphate scaffolds: An in vitro screening and in vivo validation study.

Biphasic calcium phosphate (BCP) ceramics are valued for their osteoconductive properties but have limited osteogenic and angiogenic activities, which restricts their clinical utility in bone defect repair. Silicon doping has emerged as an effective strategy to enhance these biological functions of BCP. However, the biological impact of BCP is influenced by the level of silicon doping, necessitating determination of the optimal concentration to maximize efficacy in bone repair. This study investigated the effects of silicon doping on both the physicochemical and biological properties of BCP, with a specific focus on osteogenic and angiogenic potentials. Results indicated that silicon doping exceeding 4 mol.% led to the formation of α-TCP, accelerating BCP degradation, enhancing silicon ion release, and promoting mineralization product formation. Simultaneously, silicon doping increased the porosity of BCP scaffolds, which typically reduces their compressive strength. Nevertheless, scaffolds doped with ≤4 mol.% silicon maintained compressive strengths exceeding 2 MPa. In vitro biological experiments indicated that higher levels of silicon doping (≥6 mol.%) partially inhibited the successful differentiation of stem cells and the vascularization of endothelial cells. Optimal conditions for promoting osteogenic differentiation and angiogenesis were identified between 2 and 4 mol.% silicon doping, with an optimal level of approximately 4 mol.%. Subsequent in vivo experiments confirmed that BCP scaffolds doped with 4 mol.% silicon effectively promoted vascularization and new bone formation, highlighting their potential for clinical bone defect repair.

Mechanisms of mechanical force in periodontal homeostasis: a review.

Mechanical forces affect periodontal health through multiple mechanisms. Normally, mechanical forces can boost soft and hard tissue metabolism. However, excessive forces may damage the periodontium or result in irreversible inflammation, whereas absence of occlusion forces also leads to tissue atrophy and bone resorption. We systemically searched the PubMed and Web of Science databases and found certain mechanisms of mechanical forces on immune defence, extracellular matrix (ECM) metabolism, specific proteins, bone metabolism, characteristic periodontal ligament stem cells (PDLSCs) and non-coding RNAs (ncRNAs) as these factors contribute to periodontal homeostasis. The immune defence functions change under forces; genes, signalling pathways and proteinases are altered under forces to regulate ECM metabolism; several specific proteins are separately discussed due to their important functions in mechanotransduction and tissue metabolism. Functions of osteocytes, osteoblasts, and osteoclasts are activated to maintain bone homeostasis. Additionally, ncRNAs have the potential to influence gene expression and thereby, modify tissue metabolism. This review summarizes all these mechanisms of mechanical forces on periodontal homeostasis. Identifying the underlying causes, this review provides a new perspective of the mechanisms of force on periodontal health and guides for some new research directions of periodontal homeostasis.