Targeted elimination of senescent cells by engineered extracellular vesicles attenuates atherosclerosis in ApoE-/- mice with minimal side effects.

Senescent cells in plaques emerge as a detrimental factor for atherosclerosis (AS), for which targeted senolysis might be a promising therapeutic strategy. The development of safe and efficient senolytics for senescent cell eradication by targeted delivery is greatly needed. Methods: Pro-apoptotic intelligent Bax (iBax)-overexpressing plasmid was constructed by molecular cloning, in which Bax CDS was fused to miR-122 recognition sites. Extracellular vesicle-based senolytics (EViTx) were developed to be conjugated with magnetic nanoparticles on the surface, iBax mRNA encapsulated inside, and BAX activator BTSA1 incorporated into the membrane. EViTx was characterized, and in vivo distribution was tracked via fluorescence imaging. The therapeutic effects of EViTx on AS and its systemic side effects were analyzed in ApoE-/- mice. Results: Magnetic nanoparticles, iBax mRNA and BAX activator BTSA1 were efficiently loaded into/onto EViTx. With external magnetic field navigation, EViTx was delivered into atherosclerotic plaques and induced significant apoptosis in senescent cells regardless of origins. Repeated delivery of EViTx via tail vein injection has achieved high therapeutic efficacy in ApoE-/- mice. Notably, EViTx is inevitably accumulated in liver cells, while the iBax mRNA was translationally repressed by miR-122, an endogenous miRNA highly expressed in hepatocytes, and thus the liver cells are protected from the potential toxicity of Bax mRNA. Conclusion: Our work demonstrated that magnetic EV-based delivery of iBax mRNA and the BAX activator BTSA1, efficiently induced apoptosis in recipient senescent cells in atherosclerotic plaques. This strategy represents a promising treatment approach for AS and other age-related diseases.

Smart exosomes with lymph node homing and immune-amplifying capacities for enhanced immunotherapy of metastatic breast cancer.

Tumor-draining lymph nodes (TDLNs) are the primary sites to initiate immune responses against cancer, as well as the origin of metastasis for most breast cancer cases. Reverting the immunosuppression microenvironment in TDLNs is critical to improving the outcome of the malignancy, though still a big technical challenge. In this study, a type of smart exosomes was developed in which the exosome surface was functionally engineered with CD62L (L-selectin, a gene for lymphocyte homing to lymph nodes) and OX40L (CD134L, a gene for effector T cell expansion and regulatory T cell [Treg] inhibition) by forced expression of the genes in the donor cells. Compared with control exosomes, the smart exosomes displayed strong TDLN homing capacity in the 4T1 syngeneic mouse model. Moreover, injection of the smart exosomes activated effector T cells and inhibited Treg induction, thereby amplifying the antitumor immune response and inhibiting tumor development. Together, the engineered smart exosomes provide a novel nanoplatform for TDLN-targeted delivery and cancer immunotherapy.

Microenvironment Influences on Human Umbilical Cord Mesenchymal Stem Cell-Based Bone Regeneration.

The microenvironment, or niche, regulates stem cell fate and improves differentiation efficiency. Human umbilical cord mesenchymal stem cells (hUC-MSCs) are ideal cell source for bone tissue engineering. However, the role of the microenvironments in hUC-MSC-based bone regeneration is not yet fully understood. This study is aimed at investigating the effects of the in vitro culture microenvironment (hUC-MSCs, nano-hydroxyapatite/collagen/poly (L-lactide) (nHAC/PLA), osteogenic media (OMD), and recombinant human bone morphogenetic protein-7 (rhBMP-7)) and the in vivo transplanted microenvironment (ectopic and orthotopic) on bone regeneration ability of hUC-MSCs. The isolated hUC-MSCs showed self-renewal potential and MSCs' characteristics. In the in vitro two-dimensional culture microenvironment, OMD or OMD with rhBMP-7 significantly enhanced hUC-MSCs' osteocalcin immunofluorescence staining, alkaline phosphatase, and Alizarin red staining; OMD with rhBMP-7 exhibited the highest ALP secretion and mineralized matrix formation. In the in vitro three-dimensional culture microenvironment, nHAC/PLA supported hUC-MSCs' adhesion, proliferation, and differentiation; the microenvironment containing OMD or OMD and rhBMP-7 shortened cell proliferation progression and made osteogenic differentiation progression advance; rhBMP-7 significantly attenuated the inhibiting effect of OMD on hUC-MSCs' proliferation and significantly enhanced the promoting effect of OMD on gene expression and protein secretion of osteogenic differentiation markers, calcium and phosphorous concentration, and mineralized matrix formation. The in vitro three-dimensional culture microenvironment containing OMD and rhBMP-7 induced hUC-MSCs to form the most new bones in ectopic or orthotopic microenvironment as proved by microcomputed tomography and hematoxylin and eosin staining, but bone formation in orthotopic microenvironment was significantly higher than that in ectopic microenvironment. The results indicated that the combination of in vitro hUC-MSCs+nHAC/PLA+OMD+rhBMP-7 microenvironment and in vivo orthotopic microenvironment provided a more optimized niche for bone regeneration of hUC-MSCs. This study elucidates that hUC-MSCs and their local microenvironment, or niche, play an important role in hUC-MSC-based bone regeneration. The endogenously produced BMP may serve an important regulatory role in the process.

Correction: Nanozymes go oral: nanocatalytic medicine facilitates dental health.

Correction for 'Nanozymes go oral: nanocatalytic medicine facilitates dental health' by Xiaohang Chen et al., J. Mater. Chem. B, 2021, 9, 1491-1502, DOI: 10.1039/d0tb02763d.

Nanozymes go oral: nanocatalytic medicine facilitates dental health.

Nanozymes are multi-functional nanomaterials with enzyme-like activity, which rapidly won a place in biomedicine due to their number of nanocatalytic materials types and applications. Yan and Gao first discovered horseradish peroxidase-like activity in ferromagnetic nanoparticles in 2007. With the joint efforts of many scientists, a new concept-nanocatalytic medicine-is emerging. Nanozymes overcome the inherent disadvantages of natural enzymes, such as poor environmental stability, high production costs, difficult storage and so on. Their progress in dentistry is following the advancement of materials science. The oral research and application of nanozymes is becoming a new branch of nanocatalytic medicine. In order to highlight the great contribution of nanozymes facilitating dental health, we first review the overall research progress of multi-functional nanozymes in oral related diseases, including treating dental caries, dental pulp diseases, oral ulcers and peri-implantitis; the monitoring of oral cancer, oral bacteria and ions; and the regeneration of soft and hard tissue. Additionally, we also propose the challenges remaining for nanozymes in terms of their research and application, and mention future concerns. We believe that the new catalytic nanomaterials will play important roles in dentistry in the future.

Local delivery of insulin/IGF-1 for bone regeneration: carriers, strategies, and effects.

Bone defects caused by trauma, tumor resection, congenital malformation and infection are still a major challenge for clinicians. Biomimetic bone materials have attracted more and more attention in science and industry. Insulin and insulin-like growth factor-1 (IGF-1) have been increasingly recognized as an inducible factor for osteogenesis and angiogenesis. Spatiotemporal release of insulin may serve as the promising strategy. Considering the successful application of nanoparticles in drug loading, various insulin delivery systems have been developed, including (poly (lactic-co-glycolic acid), PLGA), hydroxyapatite (HA), gelatin, chitosan, alginate, and (γ-glutamic acid)/ß-tricalcium phosphate, γ-PGA/ß-TCP). Here, we have reviewed the progress on nanoparticles carrying insulin/IGF for bone regeneration. In addition, the key regulatory mechanism of insulin in bone regeneration is also summarized. The future application strategies and the challenges in bone regeneration are also discussed.

Antibacterial peptides inhibit MC3T3-E1 cells apoptosis induced by TNF-α through p38 MAPK pathway.

BACKGROUND: Antimicrobial peptides (AMP), as a small molecular polypeptide with a broad antibacterial spectrum and high efficiency, have attracted more and more attention. Few pieces of research on the effect of the antimicrobial peptide on osteoblast under inflammatory conditions have so far been reported. The main aim of this work was to investigate the antiapoptosis effect of the antimicrobial peptide on MC3T3-E1 cells induced by TNF-α and its related mechanism. METHODS: Rat MC3T3-E1 cells were co-cultured with different concentrations of antibacterial peptide DP7 and TNF-α.MTS assay, cell scratch test, alkaline phosphatase activity, and alizarin red staining assay were used to determine osteoblast viability in this experiment. Annexin V-FITC/PI double staining cells and flow cytometry were used to analyze apoptosis and Western blot assay detection to show mitogen-activated protein kinase (MAPK) protein expression in rat MC3T3-E1 cells. Then, Realtime polymerase chain reaction (PCR) was used to examine the caspase-3 gene expression. Also, ELISA detection was used to clarify the anti-apoptotic effect of the p38 MAPK inhibitor, SB203580, on cells' apoptosis. RESULTS: Antimicrobial peptide could promote the proliferation, migration, and osteogenic ability of MC3T3-E1 cells induced by TNF-α, but inhibit cell apoptosis rate (P<0.05), and the effect was concentration-dependent. Western blot results showed after TNF-αtreatment, the expression of p-p38 MAPK in the MC3T3-E1 cells increased after TNF-α and antimicrobial peptide cotreatment, TNF-α induced p-p38 MAPK phosphorylation was inhibited, and the difference was statistically significant (P<0.05). Realtime PCR results showed that the gene expression of caspase-3 mRNA was up-regulated after TNF-α treatment, while their expression was down-regulated after cultured with TNF-α and antimicrobial peptide. Elisa's analysis showed that cell apoptosis increased after TNF-α treatment alone, and cell apoptosis was reduced to the normal levels when combined with antimicrobial peptide, and cell apoptosis induced by TNF-α was partially abolished when combined with SB203580. CONCLUSIONS: Antimicrobial peptide DP7 could inhibit MC3T3-E1 cells apoptosis induced by TNF-α, and the effect was concentration-dependent. The antiapoptosis activation of the antimicrobial peptide on MC3TE-E1 cells may be related to the inhibition of the p38 MAPK pathway.

Hierarchical assembly of nanostructured coating for siRNA-based dual therapy of bone regeneration and revascularization.

Advancing bone implant engineering offers the opportunity to overcome crucial medical challenges and improve clinical outcomes. Although the establishment of a functional vascular network is crucial for bone development, its regeneration inside bone tissue has only received limited attention to date. Herein, we utilize siRNA-decorated particles to engineer a hierarchical nanostructured coating on clinically used titanium implants for the synergistic regeneration of skeletal and vascular tissues. Specifically, an siRNA was designed to target the regulation of cathepsin K and conjugated on nanoparticles. The functionalized nanoparticles were assembled onto the bone implant to form a hierarchical nanostructured coating. By regulating mRNA transcription, the coating significantly promotes cell viability and growth factor release related to vascularization. Moreover, microchip-based experiments demonstrate that the nanostructured coating facilitates macrophage-induced synergy in up-regulation of at least seven bone and vascular growth factors. Ovariectomized rat and comprehensive beagle dog models highlight that this siRNA-integrated nanostructured coating possesses all the key traits of a clinically promising candidate to address the myriad of challenges associated with bone regeneration.

Cytotoxicity, Oxidative Stress, and Autophagy Effects of Tantalum Nanoparticles on MC3T3-E1 Mouse Osteoblasts.

As a bone implant material, porous tantalum (Ta) has better corrosion resistance and more suitable elastic modulus than titanium. Surface nanomodification can accelerate the integration of Ta implants with bone tissue, which has broad application prospects in the field of dental implantology. Due to mechanical stress and load wear, nanoscale Ta fragments are inevitably exfoliated from the implant surface and brought into direct contact with osteoblasts surrounding the implant. These wear fragments may affect the biological characteristics of osteoblasts and thus the stability of implants. To date, the interaction of nanoscale Ta fragments with osteoblasts has not been clearly investigated. In the current study, we used the mouse osteoblast cell line MC3T3-E1 to explore the effects of Ta nanoparticles (Ta-NPs) on the cytotoxicity, oxidative stress and autophagy of osteoblasts. We found that a low concentration (12.5 µg/mL) of Ta-NPs can promote the proliferation of osteoblasts, while the Ta-NPs began to induce a decrease in cell viability at concentrations ≥25 µg/mL. Increased cell mortality, reactive oxygen species (ROS) production and decreased mitochondrial membrane potential (MMP) occurred in a dose-dependent manner after Ta-NP treatment. Moreover, with Ta-NP stimulation, the ratio of LC3-II/LC3-I increased, and the level of p62 protein was reduced. However, the degradation of p62 was not continuously increased when the concentration of Ta-NPs was ≥25 µg/mL. These results indicate that Ta-NPs induced osteoblast damage via oxidative stress. Autophagy activation may be a key factor in the cellular response to Ta-NP toxicity and could have an important impact on determining the survival or death of osteoblasts.

Uniform-sized insulin-loaded PLGA microspheres for improved early-stage peri-implant bone regeneration.

Poor initial stability at the first four weeks after surgery is becoming the major causes for metal implant failure. Previous attempts neglected the control release of insulin for the bone regeneration among nondiabetic subjects. The major reason may lie in the adverse effects, such as attenuated bone formation, hypoglycemia or hyperinsulinemia, that caused by the excessive insulin. Thus, spatiotemporal release of insulin may serve as the promising strategy. To address this, through solvent extraction (EMS), solvent evaporation (SMS) and cosolvent methods (CMS), we prepared three types of PLGA microspheres with various internal structures, but similar size distribution. The effects of the preparation methods on the properties of the microspheres, such as their release behavior, degradation of molecular weight, and structural evolution, were investigated. Human bone marrow mesenchymal stromal cells (BMSCs) and rabbit implant models were used to test the bioactivity of the microspheres in vitro and in vivo, respectively. The result demonstrated that these three preparation methods did not influence the polymer degradation but instead affected the internal structural evolution, which plays a crucial role in the release behavior, osteogenesis and peri-implant bone regeneration. Compared with EMS and CMS microspheres, SMS microspheres exhibited a relatively steady release rate in the first four weeks, which evidently stimulated the osteogenic differentiation of the stem cells and peri-implant bone regeneration. Meanwhile, SMS microspheres significantly enhanced the stability of the implant at Week 4, which is promising to reduce early failure rate of the implant without inducing adverse effects on the serum biochemical indices.

[Summary of 61 cases of removable denture restoration in children with congenital tooth deficiency].

PURPOSE: To explore the methods and characteristics of removable denture restoration in children with congenital missing teeth. METHODS: From 1998 to 2018, 61 children aging 3 to 12 years old with congenital dental deficiency were treated with removable dentures. There were 59 males and 2 females. Removable denture prostheses were designed according to the characteristics of the children and the residual teeth in the mouth. There were 42 complete dentures in 21 cases, 40 single jaw complete dentures and maxillary removable partial dentures in 20 cases and 40 removable partial dentures in upper and lower jaw, totally 61 cases and 122 dentures. RESULTS: After wearing the removable denture, the appearance, chewing and pronunciation of the children were improved significantly. CONCLUSIONS: Although the etiology of congenital tooth defect is not completely clear, children can have early denture restoration. It solves the difficulty of eating, improves appearance and pronunciation, and promotes growth and physical and mental health of children.

miR-148b-3p, miR-337-5p and miR-423-5p expression in alveolar ridge atrophy and their roles in the proliferation and apoptosis of OMMSCs.

MicroRNAs (miRNAs/miRs) have key roles in various physiological and pathological processes by regulating the expression of specific genes. The identification of miRNAs involved in bone metabolism may provide insight into the expression of genes associated with the development of alveolar ridge atrophy. In the present study, the miRNA expression profiles in alveolar ridge atrophy and normal tissue samples were investigated by miRNA microarray analysis. Among the 52 differentially expressed miRNAs identified, the expression levels of 20 selected miRNAs in the alveolar ridge atrophy and normal tissue samples were verified by reverse transcription-quantitative polymerase chain reaction. The results indicated that the expression levels of 11 miRNAs were significantly different between alveolar ridge atrophy and normal tissue samples; however, only three of them (miR-148b-3p, miR-337-5p and miR-423-5p) were previously reported to be involved in bone metabolism. In vitro, miR-148b-3p, miR-337-5p and miR-423-5p mimics promoted the proliferation and inhibited apoptosis of bone marrow mesenchymal stem cells from orofacial bone (OMMSCs), while antisense inhibitors of these miRNAs had the opposite effect. In conclusion, the present study indicated that these miRNAs are involved in the pathogenesis of alveolar ridge atrophy. miR-148b-3p, miR-337-5p and miR-423-5p promote the proliferation of OMMSCs and inhibit their apoptosis. The present results provide a novel perspective for understanding the pathogenesis of alveolar ridge atrophy.

Patients with Chronic Obstructive Pulmonary Disease Suffer from Worse Periodontal Health-Evidence from a Meta-Analysis.

Background and Objective: It is widely accepted that there is an association between chronic obstructive pulmonary disease (COPD) and periodontitis. However, whether the periodontal status of the COPD patients is worse than that of the non-COPD subjects is seldom assessed. The findings currently available are inconsistent, some even contradictory. Therefore, we performed this meta-analysis to compare the periodontal health status of COPD patients and non-COPD subjects. Methods: PubMed and Embase were searched for all of the eligible studies which comparing the periodontal status between COPD patients and non-COPD subjects. The results of periodontal parameters in each study were extracted and the mean differences and 95% confidence intervals (CIs) for each parameter were calculated to determine their overall effects. Results: In total, 14 studies involving 3348 COPD patients and 20612 non-COPD controls were included and 9 periodontal indexes were analyzed. The mean differences (95% CIs) between COPD and non-COPD subjects for probing depth, clinical attachment loss, level of alveolar bone loss, plaque index, oral hygiene index, bleeding index, bleeding on probing, gingival index, and remaining teeth were 0.261 (0.020-0.501), 0.480 (0.280-0.681), 0.127 (0.000-0.254), 0.226 (0.043-0.408), 0.802 (0.326-1.279), 0.241 (-0.106 to 0.588), 6.878 (5.489-8.266), 0.364 (0.036-0.692), and -3.726 (-5.120 to -2.331), respectively. Conclusion: In summary, this meta-analysis demonstrates that the COPD patients suffer from worse periodontal health status, indicated by deeper periodontal pockets, high level of clinical attachment loss, worse oral hygiene, more inflammation and bleeding in the gingival tissue, and lower number of remaining teeth. Nevertheless, considering the limitations in our meta-analysis, more high-quality, and well-designed studies focusing on the periodontal health of the COPD patients are required to validate our conclusion.

Osseointegration of layer-by-layer polyelectrolyte multilayers loaded with IGF1 and coated on titanium implant under osteoporotic condition.

PURPOSE: Titanium implant is a widely used method for dental prosthesis restoration. Nevertheless, in patients with systemic diseases, including osteoporosis, diabetes, and cancer, the success rate of the implant is greatly reduced. This study investigates a new implant material loaded with insulin-like growth factor 1 (IGF1), which could potentially improve the implant success rate, accelerate the occurrence of osseointegration, and provide a new strategy for implant treatment in osteoporotic patients. MATERIALS AND METHODS: Biofunctionalized polyelectrolyte multilayers (PEMs) with polyethylenimine as the excitation layer and gelatin/chitosan loaded with IGF1 were prepared on the surface of titanium implant by layer-by-layer self-assembly technique. The physical and chemical properties of the biofunctionalized PEMs, the biological characteristics of bone marrow mesenchymal stem cells (BMMSCs), and bone implant contact correlation test indexes were detected and analyzed in vitro and in vivo using osteoporosis rat model. RESULTS: PEMs coatings loaded with IGF1 (TNS-PEM-IGF1-100) implant promoted the early stage of BMMSCs adhesion. Under the action of body fluids, the active coating showed sustained release of growth factors, which in turn promoted the proliferation and differentiation of BMMSCs and the extracellular matrix. At 8 weeks from implant surgery, the new bone around the implants was examined using micro-CT and acid fuchsin/methylene blue staining. The new bone formation increased with time in each group, while the TNS-PEM-IGF1-100 group showed the highest thickness and continuity. CONCLUSION: TNS-PEM-IGF1-100 new implants can promote osseointegration in osteoporotic conditions both in vivo and in vitro and provide a new strategy for implant repair in osteoporotic patients.

Evaluation of Mechanical Properties and Marginal Fit of Crowns Fabricated Using Commercially Pure Titanium and FUS-Invest.

This study investigated the mechanical properties and single crown accuracy of the tailor-made Fourth University Stomatology investment (FUS-invest) for casting titanium. Background. Current investment for casting titanium is not optimal for obtaining high-quality castings, and the commercially available titanium investment is costly. Methods. Titanium specimens were cast using the tailor-made FUS-invest. The mechanical properties were tested using a universal testing machine. Fractured castings were characterized by energy-dispersive spectroscopy. 19 titanium crowns were produced using FUS-invest and another 19 by Symbion. The accuracy of crowns was evaluated. Results. The mechanical properties of the titanium cast by FUS-invest were elastic modulus 125.6 ± 8.8 GPa, yield strength 567.5 ± 11.1 MPa, tensile strength 671.2 ± 15.6 MPa, and elongation 4.6 ± 0.2%. For marginal fit, no significant difference (P > 0.05) was found at four marker points of each group. For internal fit, no significant difference (P > 0.05) was found between two groups, whereas significant difference (P < 0.01) was found at different mark point of each group. Conclusions. The mechanical properties of titanium casted using FUS-invest fulfilled the ISO 9693 criteria. The marginal and internal fit of the titanium crowns using either the FUS-invest or Symbion were similar.

[Research on physical and mechanical properties, crown accuracy by using self- made FUS-invest dental investment].

PURPOSE: To evaluate the physical and mechanical properties of pure titanium castings cast by self- made FUS-invest dental investment, and evaluate casting accuracy. METHODS: Seven pure titanium castings were cast by self-made FUS-invest zirconium investment and analyzed using servo hydraulic dynamic experiment system (JJG139-83 standard), scanning electron microscope and energy spectrum analysis. Thirty-eight crowns of pure titanium were cast by two different methods. One cast by FUS-invest zirconium embedding material was used for experiment and the other cast by phosphate embedding material was used as control. Casting accuracy was assessed through measuring the difference value d at the marginal marker points and distance between casting pieces of wall and working modes of casting were examined under microscope. Scanning electron microscope with energy-dispersive spectrum (EDS) was used to analyze the status of composition of the casting surface. SPSS 17.0 software package was used to investigate the difference of two groups. RESULTS: ①Qualitative analysis of servo hydraulic dynamic experiment system showed various mechanical properties: elastic modulus (123.5±14.2) GPa, yield strength (569.3±16.5) MPa, tensile strength (668.4±16.1) MPa, elongation (4.5±0.2)%. EDS analysis of the fracture was observed at different depth (13, 25, 50, 350 µm) under the surface of pollution layer, a little Si and Fe with different atomic percentage was found but no Zr. ②No significant difference (P>0.05) was found between each group of four markers on the marginal fit, and internal fit, whereas significant difference (P<0.01) was found at different marker point. CONCLUSIONS: The mechanical properties of commercially pure titanium casting by self-made FUS-invest zirconium-based investment can meet the qualification of dental metal materials, although elongation was a little lower. Both the marginal adaptation and internal fit between the two groups had no significant difference. The mean marginal difference was 46 µm, the mean internal difference at axial angle was 56 µm and approximately 0 at axial wall.

Porous Nanohydroxyapatite/Collagen Scaffolds Loading Insulin PLGA Particles for Restoration of Critical Size Bone Defect.

Insulin is considered to be a classical central regulator of energy homeostasis. Recently, the effect of insulin on bone has gained a lot of attention, but little attention has been paid to the application in bone tissue engineering. In this study, porous nanohydroxyapatite/collagen (nHAC) scaffolds incorporating poly lactic-co-glycolic acid (PLGA) particles were successfully developed as an insulin delivery platform for bone regeneration. Bioactive insulin was successfully released from the PLGA particles within the scaffold, and the size of the particles as well as the release kinetics of the insulin could be efficiently controlled through Shirasu porous glass premix membrane emulsification technology. It was indicated that the nHAC/PLGA composite scaffolds possessed favorable mechanical and structural properties for cell adhesion and proliferation, as well as the differentiation into osteoblasts. It was also demonstrated that the nHAC/PLGA scaffolds implanted into a rabbit critical-size mandible defect possessed tissue compatibility and higher bone restoration capacity compared with the defects that were filled with or without nHAC scaffolds. Furthermore, the in vivo results showed that the nHAC/PLGA scaffolds which incorporated insulin-loaded microspheres with a size of 1.61 µm significantly accelerated bone healing compared with two other composite scaffolds. Our study indicated that the local insulin released at the optimal time could substantially and reproducibly improve bone repair.

Natural teeth-retained splint based on a patient-specific 3D-printed mandible used for implant surgery and vestibuloplasty: A case report.

RATIONALE: With respect to improving the quality of oral rehabilitation, the management of keratinized mucosa is as important as bone condition for implant success. To enhance this management, a natural teeth-retained splint based on a patient-specific 3-dimensional (3D) printed mandible was used in vestibuloplasty to provide sufficient keratinized mucosa around dental implants to support long-term implant maintenance. PATIENT CONCERNS: A 28-year-old male patient had a fracture of the anterior andible 1 year ago, and the fracture was treated with titanium. DIAGNOSES: The patient had lost mandibular incisors on both the sides and had a shallow vestibule and little keratinized mucosa. INTERVENTIONS: In the first-stage implant surgery, 2 implants were inserted and the titanium fracture fixation plates and screws were removed at the same time. During second-stage implant surgery, vestibuloplasty was performed, and the natural teeth-retained splint was applied. The splint was made based upon a patient-specific 3D-printed mandible. At 30-day follow-up, the splint was modified and reset. The modified splint was removed after an additional 60 days, and the patient received prosthetic treatment. OUTCOMES: After prosthetic treatment, successful oral rehabilitation was achieved. Within 1 year and 3 years after implant prosthesis finished, the patient exhibited a good quantity of keratinized gingiva. LESSONS SUBSECTIONS: The proposed splint is a simple and time-effective technique for correcting soft tissue defects in implant dentistry that ensures a good quantity of keratinized mucosa.

Restoration of a Critical Mandibular Bone Defect Using Human Alveolar Bone-Derived Stem Cells and Porous Nano-HA/Collagen/PLA Scaffold.

Periodontal bone defects occur in a wide variety of clinical situations. Adult stem cell- and biomaterial-based bone tissue regeneration are a promising alternative to natural bone grafts. Recent evidence has demonstrated that two populations of adult bone marrow mesenchymal stromal cells (BMSCs) can be distinguished based on their embryonic origins. These BMSCs are not interchangeable, as bones preferentially heal using cells that share the same embryonic origin. However, the feasibility of tissue engineering using human craniofacial BMSCs was unclear. The goal of this study was to explore human craniofacial BMSC-based therapy for the treatment of localized mandibular defects using a standardized, minimally invasive procedure. The BMSCs' identity was confirmed. Scanning electron microscopy, a cell proliferation assay, and supernatant detection indicated that the nHAC/PLA provided a suitable environment for aBMSCs. Real-time PCR and electrochemiluminescence immunoassays demonstrated that osteogenic markers were upregulated by osteogenic preinduction. Moreover, in a rabbit critical-size mandibular bone defect model, total bone formation in the nHAC/PLA + aBMSCs group was significantly higher than in the nHAC/PLA group but significantly lower than in the nHAC/PLA + preinduced aBMSCs. These findings demonstrate that this engineered bone is a valid alternative for the correction of mandibular bone defects.

Site-Specific Characteristics of Bone Marrow Mesenchymal Stromal Cells Modify the Effect of Aging on the Skeleton.

Bone is a self-renewing tissue. Bone marrow mesenchymal stromal cells (BMSCs) are located in the adult skeleton and are believed to be involved in the maintenance of skeletal homeostasis throughout life. With increasing age, the ability of the skeleton to repair itself decreases, possibly due to the reduced functional capacity of BMSCs. Recent evidence has suggested the existence of at least two populations of BMSCs with different embryonic origins that cannot be interchanged during stem cell recruitment: craniofacial BMSCs (neural crest origin) and appendicular BMSCs (mesoderm origin). Questions arise as to whether the site-specific characteristics alter the effect of aging on the skeleton. In this study, the effects of biological aging on human BMSCs were compared with BMSCs derived from the craniofacial bone versus those derived from the appendicular skeleton. The phenotype, proliferation, and functional characteristics (osteogenic differentiation, cytokine secretion, and bone formation in vivo) of the BMSCs were investigated. The results demonstrated that the proliferative capacity and osteogenic differentiation of the BMSCs decrease significantly with age both in vitro and in vivo. For age-matched groups, the osteogenic differentiation capacity of alveolar BMSCs was higher than that of femoral BMSCs in the middle-aged and old groups, while there was no significant difference for the young groups. Compared with old alveolar BMSCs, old femoral BMSCs had a significantly longer population doubling time, a smaller colony-forming population, and less bone formation in vivo, while there was no significant difference for the young and middle-aged groups. Distinct differences in the expression of cytokine factors were also found. In conclusion, human BMSCs display an age-related decrease in functional capacity, and embryonic origins may play a critical role in mediating the aging rate of BMSCs. These data provide novel insights into the skeletal site-specific characteristics of aged BMSCs.