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

Osteoporosis(OP)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 antiosteoporotic 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 bonestrengthening 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.

Expert consensus on pediatric orthodontic therapies of malocclusions in children

Malocclusion,identified by the World Health Organization(WHO)as one of three major oral diseases,profoundly impacts the dental-maxillofacial functions,facial esthetics,and long-term development of~260 million children in China.Beyond its physical manifestations,malocclusion also significantly influences the psycho-social well-being of these children.Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition,by mitigating the negative impact of abnormal environmental influences on the growth.Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development,ranging from fetal stages to the early permanent dentition phase.From an economic and societal standpoint,the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated,underlining its profound practical and social importance.This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children,emphasizing critical need for early treatment.It elaborates on corresponding core principles and fundamental approaches in early orthodontics,proposing comprehensive guidance for preventive and interceptive orthodontic treatment,serving as a reference for clinicians engaged in early orthodontic treatment.

Expert consensus on the diagnosis and therapy of endo-periodontal lesions

Endo-periodontal lesions (EPLs) involve both the periodontium and pulp tissue and have complicated etiologies and pathogenic mechanisms,including unique anatomical and microbiological characteristics and multiple contributing factors.This etiological complexity leads to difficulties in determining patient prognosis,posing great challenges in clinical practice.Furthermore,EPL-affected teeth require multidisciplinary therapy,including periodontal therapy,endodontic therapy and others,but there is still much debate about the appropriate timing of periodontal therapy and root canal therapy.By compiling the most recent findings on the etiology,pathogenesis,clinical characteristics,diagnosis,therapy,and prognosis of EPL-affected teeth,this consensus sought to support clinicians in making the best possible treatment decisions based on both biological and clinical evidence.

Experts consensus on the procedure of dental operative microscope in endodontics and operative dentistry

The dental operative microscope has been widely employed in the field of dentistry,particularly in endodontics and operative dentistry,resulting in significant advancements in the effectiveness of root canal therapy,endodontic surgery,and dental restoration.However,the improper use of this microscope continues to be common in clinical settings,primarily due to operators’insufficient understanding and proficiency in both the features and established operating procedures of this equipment.In October 2019,Professor Jingping Liang,Vice Chairman of the Society of Cariology and Endodontology,Chinese Stomatological Association,organized a consensus meeting with Chinese experts in endodontics and operative dentistry.The objective of this meeting was to establish a standard operation procedure for the dental operative microscope.Subsequently,a consensus was reached and officially issued.Over the span of about four years,the content of this consensus has been further developed and improved through practical experience.

A biomimetic nanoplatform for customized photothermal therapy of HNSCC evaluated on patient-derived xenograft models

Cancer cell membrane(CCM)derived nanotechnology functionalizes nanoparticles(NPs)to recognize homologous cells,exhibiting translational potential in accurate tumor therapy.However,these nanoplatforms are majorly generated from fixed cell lines and are typically evaluated in cell line-derived subcutaneous-xenografts(CDX),ignoring the tumor heterogeneity and differentiation from inter-and intra-individuals and microenvironments between heterotopic-and orthotopic-tumors,limiting the therapeutic efficiency of such nanoplatforms.Herein,various biomimetic nanoplatforms(CCM-modified gold@Carbon,i.e.,Au@C-CCM)were fabricated by coating CCMs of head and neck squamous cell carcinoma(HNSCC)cell lines and patient-derived cells on the surface of Au@C NP.The generated Au@C-CCMs were evaluated on corresponding CDX,tongue orthotopic xenograft(TOX),immunecompetent primary and distant tumor models,and patient-derived xenograft(PDX)models.The Au@C-CCM generates a photothermal conversion efficiency up to 44.2% for primary HNSCC therapy and induced immunotherapy to inhibit metastasis via photothermal therapy-induced immunogenic cell death.The homologous CCM endowed the nanoplatforms with optimal targeting properties for the highest therapeutic efficiency,far above those with mismatched CCMs,resulting in distinct tumor ablation and tumor growth inhibition in all four models.This work reinforces the feasibility of biomimetic NPs combining modular designed CMs and functional cores for customized treatment of HNSCC,can be further extended to other malignant tumors therapy.

Magnesium alloys in tumor treatment:Current research status, challenges and future prospects

Cancer is a major threat to human life worldwide. Traditional cancer treatments, such as chemotherapy and surgery, have major limitations and can cause irreversible damage to normal tissues while killing the cancer cells. Magnesium(Mg) alloys are widely reported novel potential biomedical materials with acceptable mechanical properties and good osteogenic and angiogenic properties. In this review, we summarize the Mg alloys for antitumor applications, including pure Mg and Mg alloys(Mg-Ag, Mg-Gd, Mg-Li-Zn, Mg-Ca-Sr-Zn, et al.) fabricated by casting and extruding, selective laser melting methods. Mg alloys can exhibit antitumor effect on bone tumor, breast cancer, and liver tumor,etal. What's more, after tumor tissue is eliminated, Mg alloys prevent tumor recurrence, fill tissue defects and promote tissue regeneration.The antitumor effects of Mg alloys are mainly due to their degradation products. Overall, Mg alloys show great potential in tumor treatments due to the dual function of antitumor and tissue regeneration.

Comparison of microRNA profiles of human periodontal diseased and healthy gingival tissues

MicroRNAs （miRNAs） have been clemonstrated to play an important role in regulation of the immunoinflammatory response; however, the function of miRNAs in periodontal inflammation has not been investigated. The objective of this study was to explore the properties of miRNAs in periodontal inflammation by comparing miRNA profiles of inflamed and healthy gingival tissues. Gingival tissues were obtained from 10 periodontitis patients and 10 healthy subjects. After RNA extraction, miRNA profiles were analyzed by microarray, and expression levels of selected miRNAs were confirmed by real-time quantitative reverse transcription polymerase chain reaction （RT-PCR）. Analyses using two computational methods, Targetscan and MicroRNA.org, were combined to identify common targets of these miRNAs. Finally, the individual miRNA expression levels of three toll-like receptor （TLR）-related miRNAs from inflamed and healthy gingival tissues were evaluated by RT-PCR. Ninety-one miRNAs were found to be upregulated and thirty-four downregulated over two-fold in inflamed gingival tissue compared with those in healthy gingival tissue. Twelve selected inflammatory-related miRNAs, hsa-miR-126＊, hsa-miR-20a, hsa-miR-142-3p, hsa-miR-19a, hsa-let-7f, hsa-miR-203, hsa-miR-17, hsa-miR-223, hsa-miR-146b, hsa-miR-146a, hsa-miR-155, and hsa-miR-205 showed comparable expression levels by microarray and real-time quantitative RT-PCR analyses. In addition, the putative inflammation targets of these miRNAs were predicted, and three that were tested （hsa-miRNA-146a, hsa-miRNA-146b, and hsa-miRNA-155）, showed significant differences between inflamed and healthy gingiva. This remarkable difference in miRNA profiles between periodontal diseased and healthy gingiva implicates a probable close relationship between miRNAs and periodontal inflammation. The data also suggest that the regulation of TLRs in periodontal inflammation may involve miRNA pathways.

Sequential Fluorescent Labeling Observation of Maxillary Sinus Augmentation by a Tissue-engineered Bone Complex in Canine Model

Aim To evaluate the effects of maxillary sinus floor elevation by a tissue-engineered bone complex of β-tricalcium phosphate （β-TCP） and autologous osteoblasts in dogs. Methodology Autologous osteoblasts from adult Beagle dogs were cultured in vitro. They were further combined with β-TCP to construct the tissue-engineered bone complex. 12 cases of maxillary sinus floor elevation surgery were made bilaterally in 6 animals and randomly repaired with the following 3 groups of materials： Group A （osteoblasts/D-TCP）; Group B （β-TCP）; Group C （autogenous bone） （n=4 per group）. A polychrome sequential fluorescent labeling was performed post-operatively and the animals were sacrificed 24 weeks after operation for histological observation.Results Our results showed that autologous osteoblasts were successfully expanded and the osteoblastic phenol- types were confirmed by ALP and Alizarin red staining. The cells could attach and proliferate well on the surface of the ~3-TCP scaffold. The fluorescent and histological observation showed that the tissue-engineered bone complex had an earlier mineralization and more bone formation inside the scaffold than β-TCP along or even autologous bone. It had also maximally maintained the elevated sinus height than both control groups. Conclusion Porous 13-TCP has served as a good scaffold for autologous osteoblasts seeding. The tissue-engineered bone complex with β-TCP and autologous osteoblasts might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation.

In vitro study of the PLLA-Mg_(65)Zn_(30)Ca_(5)composites as potential biodegradable materials for bone implants

PLLA-magnesium composites have been widely investigated as potential biodegradable materials for bone implants.Lower/higher corrosion resistance of the crystalized/amorphous magnesium alloys allows tailoring of biodegradability rate.In this work,the amorphous Mg_(65)Zn_(30)Ca_(5)was investigated versus traditional crystalized Mg_(65)Zn_(30)Ca_(5),and a PLLA-Mg_(65)Zn_(30)Ca_(5)composite has been successfully fabricated using hot injection process.Furthermore,the high corrosion resistance of the amorphous Mg_(65)Zn_(30)Ca_(5)prevented the high alkalization and deterioration of mechanical strength.In addition,the high Zn content intended to improve the glass forming ability,also enhances the anti-bacterial property of the PLLA-Mg_(65)Zn_(30)Ca_(5)composite.The remarkable performance of the PLLA-Mg_(65)Zn_(30)Ca_(5)composite shows its promising application in bone repair and tissue regeneration.

ONE CASE REPORT OF REHABILITATION OF MIDFACIAL DEFECT USING SEMI-PRECISION ATTACHMENTS

Objective To discuss the application of semi-precision attachment in restoring a midfacial defect, including a nasal, upper lip, and anterior maxillary defect. Methods A splinted metal-ceramic crowns （from the upper right first molar to left molar） and a bar with stud attachments was done. A removable partial denture （RPD） containing the patrix portion of the attachment was then designed to restore the missing maxillary anterior teeth and alveolar ridge. Finally,, The facial prosthesis was joined to the denture utilizing two retentive metal posts on the superior aspect of the removable partial. Results A splinted metal-ceramic crowns （from the upper right frst molar to left molar） and a bar with stud attachments was done. A RPD containing the patrix portion of the attachment was then designed to restore the missing maxillary anterior teeth and alveolar ridge. Finally, The facial prosthesis was joined to the denture utilizing two retentive metal posts on the superior aspect of the removable partial. The prosthesis markedly improved the appearance of the patient and demonstrated good retention. Conclusion Using attachment in restoring rnaxillofacial defect may provide adequate retetion which lead to a sucessful treatment outcome.

NEW ANTIMICROBIAL SENSITIVITY TESTS OF BIOFILM OF STREPTOCOCCUS MUTANS IN ARTIFICIAL MOUTH MODEL

Objective To develop a new antimicrobial sensitivity test model for oral products in vitro.Methods A biofilm artificial mouth model for antimicrobial sensitivity tests was established by modifying the LKB chromatography chamber. Using sodium fluoride and Tea polyphenol as antimicrobial agent and Streptococcus mu-tans as target, sensitivity tests were studied. Results The modeling biofilm assay resulted in a MIC of 1. 28mg/ ml for fluoride against S. mutans, which was 32 times the MIC for broth maco-dilution method. The differential resistance of bacteria bioflim to antimicrobial agent relative to planktonic cells was also demonstrated. Conclusion The biofilm artificial mouth model may be useful in oral products test.

Micromechanical interlocking structure at the filler/resin interface for dental composites: a review

Dental resin composites(DRCs)are popular materials for repairing caries or dental defect,requiring excellent properties to cope with the complex oral environment.Filler/resin interface interaction has a significant impact on the physicochemical/biological properties and service life of DRCs.

LITTIP/Lgr6/HnRNPK complex regulates cementogenesis via Wnt signaling

Orthodontically induced tooth root resorption(OIRR)is a serious complication during orthodontic treatment.Stimulating cementum repair is the fundamental approach for the treatment of OIRR.Parathyroid hormone(PTH)might be a potential therapeutic agent for OIRR,but its effects still lack direct evidence,and the underlying mechanisms remain unclear.This study aims to explore the potential involvement of long noncoding RNAs(lncRNAs)in mediating the anabolic effects of intermittent PTH and contributing to cementum repair,as identifying lncRNA-disease associations can provide valuable insights for disease diagnosis and treatment.Here,we showed that intermittent PTH regulates cell proliferation and mineralization in immortalized murine cementoblast OCCM-30 via the regulation of the Wnt pathway.In vivo,daily administration of PTH is sufficient to accelerate root regeneration by locally inhibiting Wnt/β-catenin signaling.Through RNA microarray analysis,lncRNA LITTIP(LGR6 intergenic transcript under intermittent PTH)is identified as a key regulator of cementogenesis under intermittent PTH.Chromatin isolation by RNA purification(ChIRP)and RNA immunoprecipitation(RIP)assays revealed that LITTIP binds to mRNA of leucine-rich repeatcontaining G-protein coupled receptor 6(LGR6)and heterogeneous nuclear ribonucleoprotein K(HnRNPK)protein.Further cotransfection experiments confirmed that LITTIP plays a structural role in the formation of the LITTIP/Lgr6/HnRNPK complex.Moreover,LITTIP is able to promote the expression of LGR6 via the RNA-binding protein HnRNPK.Collectively,our results indicate that the intermittent PTH administration accelerates root regeneration via inhibiting Wnt pathway.The lncRNA LITTIP is identified to negatively regulate cementogenesis,which activates Wnt/β-catenin signaling via high expression of LGR6 promoted by HnRNPK.

Glycerol solutions of highly concentrated biomineral counter-ions towards water-responsive mineralization: Demonstration on bacterial cellulose and its application in hard tissue repair

Mineralization has found widespread use in the fabrication of composite biomaterials for hard tissue regeneration.The current mineralization processes are mainly carried out in neutral aqueous solutions of biomineral counter-ions(a pair of cation and anion that form the corresponding minerals at certain conditions),which are stable only at very low concentrations.This typically results in inefficient mineralization and weak control over biomineral formation.Here,we find that,in the organic solvent glycerol,a variety of biomineral counter-ions(e.g.,Ca/PO_(4),Ca/CO_(3),Ca/SO_(4),Mg/PO_(4),or Fe/OH)corresponding to distinct biominerals at significantly high concentrations(up to hundreds-fold greater than those of simulated body fluid(SBF))are able to form translucent and stable solutions(mineralizing solution of highly concentrated counter-ions(MSCIs)),and mineralization can be triggered upon them with external solvents(e.g.,water or ethanol).Furthermore,with pristine bacterial cellulose(BC)membrane as a model,we demonstrate an effective and controllable mineralization performance of MSCIs on organic substrates.This approach not only forms the homogeneous biominerals on the BC fibers and in the interspaces,but also provides regulations over mineralization rate,mineral content,phase,and dopants.The resulting mineralized BC membranes(MBCs)exhibit high cytocompatibility and favor the proliferation of rat bone marrow mesenchymal stem cells(rBMSC).Following this,we prepare a mineralized bone suture(MBS)from MBC for non-weight bearing bone fixation,which then is tested on a rabbit median sternotomy model.It shows firm fixation of the rabbit sternum without causing discernible toxicity or inflammatory response.This study,by extending the mineralization to the organic solution system of highly concentrated counter-ions,develops a promising strategy to design and build targeted mineral-based composites.

A five-in-one novel MOF-modified injectable hydrogel with thermo-sensitive and adhesive properties for promoting alveolar bone repair in periodontitis:Antibacterial,hemostasis,immune reprogramming,pro-osteo-/angiogenesis and recruitment

Periodontitis is a chronic inflammatory disease caused by plaque that destroys the alveolar bone tissues,resulting in tooth loss.Poor eradication of pathogenic microorganisms,persistent malignant inflammation and impaired osteo-/angiogenesis are currently the primary challenges to control disease progression and rebuild damaged alveolar bone.However,existing treatments for periodontitis fail to comprehensively address these issues.Herein,an injectable composite hydrogel(SFD/CS/ZIF-8@QCT)encapsulating quercetin-modified zeolitic imidazolate framework-8(ZIF-8@QCT)is developed.This hydrogel possesses thermo-sensitive and adhesive properties,which can provide excellent flowability and post-injection stability,resist oral fluid washout as well as achieve effective tissue adhesion.Inspirationally,it is observed that SFD/CS/ZIF-8@QCT exhibits a rapid localized hemostatic effect following implantation,and then by virtue of the sustained release of zinc ions and quercetin exerts excellent collective functions including antibacterial,immunomodulation,pro-osteo-/angiogenesis and pro-recruitment,ultimately facilitating excellent alveolar bone regeneration.Notably,our study also demonstrates that the inhibition of osteo-/angiogenesis of PDLSCs under the periodontitis is due to the strong inhibition of energy metabolism as well as the powerful activation of oxidative stress and autophagy,whereas the synergistic effects of quercetin and zinc ions released by SFD/CS/ZIF-8@QCT are effective in reversing these biological processes.Overall,our study presents innovative insights into the advancement of biomaterials to regenerate alveolar bone in periodontitis.

Recent advances in cell sheet technology for bone and cartilage regeneration: from preparation to application

Bone defects caused by trauma,tumour resection,infection and congenital deformities,together with articular cartilage defects and cartilage–subchondral bone complex defects caused by trauma and degenerative diseases,remain great challenges for clinicians.Novel strategies utilising cell sheet technology to enhance bone and cartilage regeneration are being developed.The cell sheet technology has shown great clinical potential in regenerative medicine due to its effective preservation of cell–cell connections and extracellular matrix and its scaffold-free nature.This review will first introduce several widely used cell sheet preparation systems,including traditional approaches and recent improvements,as well as their advantages and shortcomings.Recent advances in utilising cell sheet technology to regenerate bone or cartilage defects and bone–cartilage complex defects will be reviewed.The key challenges and future research directions for the application of cell sheet technology in bone and cartilage regeneration will also be discussed.

Single-cell RNA-Seq reveals transcriptional regulatory networks directing the development of mouse maxillary prominence

During vertebrate embryonic development,neural crest-derived ectomesenchyme within the maxillary prominences undergoes precisely coordinated proliferation and differentiation to give rise to diverse craniofacial structures,such as tooth and palate.However,the transcriptional regulatory networks underpinning such an intricate process have not been fully elucidated.Here,we perform single-cell RNA-Seq to comprehensively characterize the transcriptional dynamics during mouse maxillary development from embryonic day(E)10.5eE14.5.Our single-cell transcriptome atlas of~28,000 cells uncovers mesenchymal cell populations representing distinct differentiating states and reveals their developmental trajectory,suggesting that the segregation of dental from the palatal mesenchyme occurs at E11.5.Moreover,we identify a series of key transcription factors(TFs)associated with mesenchymal fate transitions and deduce the gene regulatory networks directed by these TFs.Collectively,our study provides important resources and insights for achieving a systems-level understanding of craniofacial morphogenesis and abnormality.