Osteoclast-Driven Osteogenesis, Bone Remodeling and Biomaterial Resorption: A New Profile of BMP2-CPC-Induced Alveolar Bone Regeneration.

This bedside-to-bench study aimed to systematically investigate the value of applying BMP2-loaded calcium phosphate cement (BMP2-CPC) in the restoration of large-scale alveolar bone defects. Compared to deproteinized bovine bone (DBB), BMP2-CPC was shown to be capable of inducing a favorable pattern of bone regeneration and bone remodeling accompanied by active osteoclastogenesis and optimized biomaterial resorption when applied in reconstructive periodontally accelerated osteogenic orthodontics (PAOO) surgery. To verify the regulatory role of osteoclasts in the BMP2-CPC-induced pattern of bone regeneration, in vitro and in vivo studies were designed to elucidate the underlying mechanism. Our results revealed that osteoclasts played a multifaceted role (facilitating osteogenesis, bone remodeling and biomaterial resorption) in the BMP2-CPC-induced bone regeneration. Osteoclasts contributed to the osteogenic differentiation of mesenchymal stem cells (MSCs) by secreting calcium ions, CTHRC1 and PDGF-B. Moreover, the increased osteoclasts promoted the remodeling of new bone and BMP2-CPC resorption, leading to a harmonized replacement of biomaterials with mature bone. In conclusion, the in vitro and in vivo experimental results corresponded with the clinical results and showed the optimized properties of BMP2-CPC in activating osteoclast-driven bone regeneration and remodeling, thus indicating the highly promising prospects of BMP2-CPC as an ideal therapeutic for alveolar bone defects.

Satb2 expression in Foxc1-promoted osteogenic differentiation of MC3T3-E1 cells is negatively regulated by microRNA-103-3p.

The forkhead transcription factor C1 (Foxc1) is a cell-fate-determining factor that controls cranial bone development and osteogenic differentiation. Previously, it was demonstrated that various microRNAs (miRNAs) play important roles in osteogenesis and regulate the complex process of osteogenic differentiation. However, it remains unclear how miRNA expression changes during Foxc1-promoted osteogenic differentiation. In this study, we successfully overexpressed the Foxc1 gene in MC3T3-E1 cells and investigated the alterations in the miRNA expression profile on day 3 after osteogenic induction by using a miRNA microarray. Nine downregulated miRNAs and eight upregulated miRNAs were found to be differentially expressed. Among these miRNAs, miR-103-3p was consistently downregulated in the Foxc1-overexpressing MC3T3-E1 cells and was identified as a negative regulator of osteogenic differentiation by using a gain- and lose-of-function assay. The special AT-rich sequence-binding protein 2 (Satb2), a pivotal osteogenic transcription factor, was identified as the miR-103-3p targeting gene and was verified by real-time polymerase chain reaction, western blot analysis, and luciferase assay. Overexpression of miR-103-3p markedly inhibited the expression of Satb2 and attenuated Foxc1-promoted osteogenic differentiation. Taken together, our results elucidated the miRNA expression profiles of MC3T3-E1 cells in the early stage of Foxc1-promoted osteogenic differentiation and suggested that miR-103-3p acts as a negative regulator of the osteogenic differentiation of MC3T3-E1 cells by directly targeting Satb2.

Amniotic fluid-derived stem cells mixed with platelet rich plasma for restoration of rat alveolar bone defect.

Stem cells isolated from the amniotic fluid have been shown as a promising candidate for cell therapy and tissue engineering. However, the experimental and preclinical applications of amniotic fluid-derived stem cells (AFSCs) in the very field of maxillofacial bone tissue engineering are still limited. In this study, rat AFSCs were successfully harvested and characterized in vitro. The rat AFSCs showed typical fibroblastoid morphology, stable proliferation activity and multi-differentiation potential. Flow-cytometry analysis demonstrated that these cells were positive for CD29, CD44, and CD90, while negative for hematopoietic markers such as CD34 and CD45. The regenerative performance of AFSCs-premixed with platelet rich plasma (PRP) gel in restoration of alveolar bone defect was further investigated using a modified rat maxillary alveolar defect model. Micro-computer tomography and histological examination showed a superior regenerative capacity of AFSCs-premixed with PRP gel at both 4 and 8 weeks after operation comparing with control groups. Moreover, the implanted AFSCs can survive in the defect site and directly participate in the bone tissue regeneration. Taken together, these results indicated the feasibility of an AFSCs-based alveolar bone tissue engineering strategy for alveolar defect restoration.

Tcof1-Related Molecular Networks in Treacher Collins Syndrome.

Treacher Collins syndrome (TCS) is a rare, autosomal-dominant disorder characterized by craniofacial deformities, and is primarily caused by mutations in the Tcof1 gene. This article was aimed to perform a comprehensive literature review and systematic bioinformatic analysis of Tcof1-related molecular networks in TCS. First, the up- and down-regulated genes in Tcof1 heterozygous haploinsufficient mutant mice embryos and Tcof1 knockdown and Tcof1 over-expressed neuroblastoma N1E-115 cells were obtained from the Gene Expression Omnibus database. The GeneDecks database was used to calculate the 500 genes most closely related to Tcof1. Then, the relationships between 4 gene sets (a predicted set and sets comparing the wildtype with the 3 Gene Expression Omnibus datasets) were analyzed using the DAVID, GeneMANIA and STRING databases. The analysis results showed that the Tcof1-related genes were enriched in various biological processes, including cell proliferation, apoptosis, cell cycle, differentiation, and migration. They were also enriched in several signaling pathways, such as the ribosome, p53, cell cycle, and WNT signaling pathways. Additionally, these genes clearly had direct or indirect interactions with Tcof1 and between each other. Literature review and bioinformatic analysis finds imply that special attention should be given to these pathways, as they may offer target points for TCS therapies.

Irf6-Related Gene Regulatory Network Involved in Palate and Lip Development.

Numerous genes including Irf6 have been revealed to contribute to cleft lip with or without cleft palate (CL/P). In this study, we performed a systematic bioinformatics analysis of Irf6-related gene regulatory network involved in palate and lip development by using GeneDecks, DAVID, STRING, and GeneMANIA database. Our results showed that many CL/P candidate genes have relation with Irf6, and 9 of these genes, including Msx1, Pvrl1, Pax9, Jag2, Irf6, Tgfb3, Rara, Gli2, and Tgfb2, were enriched into the CL/P gene group. Some of these 9 genes also were commonly involved in different signaling pathways and different biological processes, and they also have protein-protein interactions with Irf6. These findings make us analyze the intricate function of Irf6 in a CL/P gene regulatory network, followed by guiding us to perform further functional studies on these genes in the future. This method also offers us a simple, cheap, but useful method to analyze the relationship with a gene regulatory network of a certain disease such as CL/P.

A correlational study of serum alkaline phosphatase level and developmental mandibular laterognathism.

The abnormal cartilage/bone metabolism in unilateral condyle may be a direct factor that contributes to developmental mandibular laterognathism. However, although many molecules have been demonstrated to play crucial roles in the development of temporomandibular joints, the exact molecular mechanisms that lead to the disrupted condylar cartilage/bone development were greatly unknown. In this retrospective study, our findings revealed that serum alkaline phosphatase (ALP) level in adult patients with developmental mandibular laterognathism was lower than that in control subjects, and the serum ALP levels continue to reduce in adult patients (>20 years old). Although the exact relationship between the lower serum ALP level and developmental mandibular laterognathism is unclear, the findings further support the opinion that the condylar growth may sustain for a long time in the affected condyle in patients with developmental mandibular laterognathism and offer an alternative choice to use total serum ALP activity as a possible biomarker to assess condylar growth activity in patients with developmental mandibular laterognathism.

Characterization of a micro-roughened TiO2/ZrO2 coating: mechanical properties and HBMSC responses in vitro.

Previous studies have shown that using ZrO2 as a second phase to bioceramics can significantly increase the bonding strength of plasma-sprayed composite material. In the present study, micro-roughened titanium dioxide/zirconia (TiO2/ZrO2) (30 wt% ZrO2) coating and TiO2 coating were plasma-sprayed onto Ti plates. The micro-structural characteristics and mechanical properties of both coatings were investigated. Furthermore, the biological behavior and osteogenic differentiation of human bone marrow mesenchymal stem cells (HBMSCs) on both TiO2/ZrO2 and TiO2 coatings were compared. The results indicated that the shear bond strength and microhardness of TiO2/ZrO2 coating were statistically higher than those of TiO2 coating. Scanning electron microscope observation revealed that more irregularly shaped protuberances and denser pores were formed on the surface of TiO2/ZrO2 coating compared with those of TiO2 coating. Further comparative analysis of HBMSC proliferation and osteogenic differentiation on both coatings showed that significantly higher cellular alkaline phosphatase activity and expression levels of Runx2 and Osterix at day 10 after osteogenic culture were found on TiO2/ZrO2 coating compared with TiO2 coating, while no statistically significant difference in cell proliferation and extracellular calcium deposition was observed. The present study suggests that TiO2/ZrO2 coating may be favorable for dental implant applications.

Accurate movement of jaw segment in virtual 3D orthognathic surgery.

In traditional virtual 3D orthognathic surgery, after repositioning the maxillary segment to the desired position, surgeons usually roughly rotate or adjust the mandibular segment to obtain a relatively good relationship with maxillary dentition to calculate the virtual terminal occlusion splint. However, surgeons are not easy to avoid penetrability, overlap, or an overly large space existing between the maxillary and mandibular dentitions during this process. The present report offered a new method to obtain a suitable virtual terminal occlusal splint that could avoid penetrability, overlap, or an overly large space between the maxillary and mandibular dentitions, and simultaneously accurately moving the maxillary or mandibular segment to the desired position utilizing the planned terminal occlusion plaster models in virtual orthognathic surgery. For double jaw surgery, after aligning the planned plaster models to the 3D maxilla and mandible, we could simultaneously move the maxillary and mandibular segment as a whole that maintain the planned terminal occlusion to the desired position. This present method may enhance the accuracy of 3D virtual orthognathic surgery and save plenty of time spend on virtual surgery simulation, which also offers a useful educational method for training junior surgeons and students.

Evaluation of optimal single-photon emission computed tomography reference value and three-dimensional mandibular growth pattern in 54 Chinese unilateral condylar hyperplasia patients.

BACKGROUND: The research aimed to evaluate the optimal Single-Photon Emission Computed Tomography (SPECT) cut-off value in differentiating condylar growth activeness, to observe 3-dimensional (3D) mandibular growth pattern, and to explore the potential correlation between 3D measurement parameters and SPECT uptake ratios in Chinese unilateral condylar hyperplasia (UCH) patients. METHODS:  Data of fifty-four Chinese UCH patients were analyzed retrospectively. All patients underwent SPECT within 1 month before or after the first CT examination (CT1); and received a second CT examination at least 12 months later (CT2). Data from CT scans were analyzed by comparing bilateral differences between CT1 and CT2. The sensitivity and specificity of SPECT were calculated by the receiver operating characteristic (ROC) curve. Pearson's correlation analysis was performed to investigate whether the mandibular growth was correlated with SPECT value. RESULTS: SPECT had a sensitivity of 68.00% and a specificity of 72.41%, with an area under the ROC curve being 0.709. The optimal SPECT cut-off value for evaluating condylar activity has been determined to be 13%. In patients with an active growing condyle, there was a significant increase in Co-Gn and Co-Go, but not in Go-Gn, Go-MF, or MF-Gn. Pearson's correlation analysis revealed no correlation between 3D measurement parameters and differences in relative condylar uptake ratios. CONCLUSION: SPECT showed good diagnostic performance in UCH with the cut-off value of 13%. For those with an active growing condyle, the mandible grows diagonally and vertically, while the relative condylar uptake ratio was not directly related to mandibular growth.

Intraoral Condylectomy with 3D-Printed Cutting Guide versus with Surgical Navigation: An Accuracy and Effectiveness Comparison.

This study compares the accuracy and effectiveness of our novel 3D-printed titanium cutting guides with intraoperative surgical navigation for performing intraoral condylectomy in patients with mandibular condylar osteochondroma (OC). A total of 21 patients with mandibular condylar OC underwent intraoral condylectomy with either 3D-printed cutting guides (cutting guide group) or with surgical navigation (navigation group). The condylectomy accuracy in the cutting guide group and navigation group was determined by analyzing the three-dimensional (3D) discrepancies between the postoperative computed tomography (CT) images and the preoperative virtual surgical plan (VSP). Moreover, the improvement of the mandibular symmetry in both groups was determined by evaluating the chin deviation, chin rotation and mandibular asymmetry index (AI). The superimposition of the condylar osteotomy area showed that the postoperative results were very close to the VSP in both groups. The mean 3D deviation and maximum 3D deviation between the planned condylectomy and the actual result were 1.20 ± 0.60 mm and 2.36 ± 0.51 mm in the cutting guide group, and 1.33 ± 0.76 mm and 4.27 ± 1.99 mm in the navigation group. Moreover, the facial symmetry was greatly improved in both groups, indicated by significantly decreased chin deviation, chin rotation and AI. In conclusion, our results show that both 3D-printed cutting-guide-assisted and surgical-navigation-assisted methods of intraoral condylectomy have high accuracy and efficiency, while using a cutting guide can generate a relatively higher surgical accuracy. Moreover, our cutting guides exhibit user-friendly features and simplicity, which represents a promising prospect in everyday clinical practice.

[In vitro biological evaluation of PEGylated poly(glycerol sebacate)/ß-TCP-coating modified magnesium alloy].

PURPOSE: To prepare PEGS/ß-TCP modified magnesium alloy (PEGS/ß-TCP/MZG) membranes by forming a glycolated poly(sebacate)/ß-tricalcium phosphate (PEGS/ß-TCP) coating on the surface of magnesium-zinc-gadolinium alloy (MZG) membranes, and to evaluate the osteogenic induction activity and immunomodulatory properties of PEGS/ß-TCP/MZG using the material extract medium. METHODS: PEGS/ß-TCP coating was prepared on the surface of MZG by solvent method, and the PEGS/ß-TCP/MZG membrane was fabricated and compared with PEGS/ß-TCP and MZG to examine the morphology, composition, and hydrophilicity. The amount of magnesium ions released and the pH value of the materials were tested after 3 days of immersion. The cell viability and osteogenic differentiation of MC3T3 cells induced by extract medium were investigated by CCK-8 assay, ALP and mineralized nodule staining. The cell viability and polarization of RAW cells induced by extract medium were then investigated. The expression of macrophage-secreted cytokines was examined by PCR analysis. GraphPad Prism 9.0 software package was used for statistical analysis. RESULTS: PEGS/ß-TCP/MZG membranes with PEGS/ß-TCP coating tightly embedded with MZG were successfully fabricated, and the material had good hydrophilicity. The results of degradation experiments indicated that the PEGS/ß-TCP coating effectively slowed down the degradation rate of MZG, leading to a lower pH value and concentration of Mg2+ ion in the extract medium of PEGS/ß-TCP/MZG group. The results of in vitro cell experiments showed that PEGS/ß-TCP/MZG had no significant effect on the proliferation activity of both MC3T3-E1 and macrophages. PEGS/ß-TCP/MZG significantly enhanced the expression of ALP and mineralized nodule staining in MC3T3-E1. Although there was no significant difference in macrophage polarization pattern between PEGS/ß-TCP and PEGS/ß-TCP/MZG groups, PEGS/ß-TCP/MZG further reduced inflammation based on the immunomodulation of PEGS/ß-TCP coating related TNF-α expression and increased osteogenesis related TGF-ß expression. CONCLUSIONS: MZG membrane modified by PEGS/ß-TCP may provide a new material option for the development of bone tissue engineering.

HIF-1α Regulates Osteogenesis of Periosteum-Derived Stem Cells Under Hypoxia Conditions via Modulating POSTN Expression.

Periosteum is indispensable in bone repair and is an important source of skeletal stem cells (SSCs) for endogenous bone regeneration. However, there are only a few studies about SSCs in periosteum. The craniomaxillofacial bone regeneration is done under the hypoxia microenvironment, in which HIF-1α plays an important role. The effect of HIF-1α on periosteum-derived stem cells (PDSCs) and the mechanisms of PDSCs activation under hypoxia conditions are unknown. In this study, the calvarial bone defect was established, with the periosteum removed or retained. Results show that the bone regeneration was severely impaired in the periosteum removed group. Moreover, pluripotent PDSCs isolated from the periosteum were positive for mesenchymal stem cell (MSC) markers. To determine the role of HIF-1α, the expression of HIF-1α was knocked down in vivo and in vitro, impairing the bone regeneration or osteogenesis of PDSCs. Furthermore, the knockdown of HIF-1α expression also reduced periostin (POSTN) expression, and recombinant POSTN addition partly rescued the osteogenic inhibition. Finally, to explore the mechanism under POSTN activation, the phosphorylation level of the PI3K/AKT pathway was assessed in transfected PDSCs. The phosphorylation level of PI3K and AKT was enhanced with HIF-1α overexpression and inhibited with HIF-1α knockdown, and the addition of PI3K activator or AKT activator could partly rescue POSTN expression. In conclusion, as a potential target to promote bone repair under the hypoxia microenvironment, HIF-1α can regulate the osteogenic differentiation of PDSCs via the PI3K/AKT/POSTN pathway, which lay a solid foundation for periosteum-based craniomaxillofacial bone regeneration.

The strategy of composite grafting with BMP2-Loaded calcium phosphate cements and autogenous bone for alveolar cleft reconstruction.

Purpose: To remedy the drawbacks of traditional autogenous bone harvesting in alveolar bone grafting (ABG), a novel strategy of composite grafting with BMP2-loaded calcium phosphate cements (BMP2-CPC) and autogenous bone harvested by minimally invasive technique was developed and evaluated for its bone-repairing efficacy. Materials and methods: A chart review was conducted for 19 patients with unilateral alveolar clefts who underwent secondary ABG from 2017 to 2020. Of the enrolled patients, 9 patients underwent grafting with autogenous bone harvested by traditional trap door technique (group I), and 10 patients underwent grafting with the composite graft comprising BMP2-CPC and autogenous bone harvested by minimally invasive technique at a ratio of 1:1 by volume (group II). The clinical performance of the composite graft was comprehensively evaluated in terms of clinical, radiographic and histological perspectives. Results: The present results demonstrated that the composite graft exhibited satisfactory bone-repairing efficacy comparable to that of the autogenous bone graft on the premise of lower amount of harvested bone. The post-surgical resorption of bone volume and vertical height of grafted area was significantly slower in group II. The favourable resorption performance of BMP2-CPC contributed to preserving the post-surgical bony contour reconstructed with the composite graft. Conclusion: The composite graft comprising BMP2-CPC and autogenous bone harvested by minimally invasive technique was demonstrated to be an eligible alternative for application in ABG, especially for its improved resorption performance in preserving post-surgical bony contour.

Small extracellular vesicles derived from hypoxic mesenchymal stem cells promote vascularized bone regeneration through the miR-210-3p/EFNA3/PI3K pathway.

Angiogenesis is closely coupled with osteogenesis and has equal importance. Thus, promoting angiogenesis during the bone repair process is vital for ideal bone regeneration. As important mediators of cell-cell communication and biological homeostasis, mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) have been proved to be highly involved in bone and vascular regeneration. Because hypoxia microenvironment promotes the proangiogenic activity of MSCs, in the present study, we investigate the effect and underlying molecular mechanisms of sEVs from hypoxia-preconditioned MSCs (hypo-sEVs) on angiogenesis and develop an effective strategy to promote vascularized bone regeneration. Compared to sEVs from normoxia MSCs (nor-sEVs), hypo-sEVs promoted the proliferation, migration, and angiogenesis of HUVECs and ultimately enhanced bone regeneration and new blood vessel reconstruction in a critical-size calvarial bone defect model. miRNA sequence and the verified results showed that miR-210-3p in hypo-sEVs was increased via HIF-1α under hypoxia. The upregulated miR-210-3p in hypo-sEVs promoted angiogenesis by downregulating EFNA3 expression and enhancing the phosphorylation of the PI3K/AKT pathway. Thus, this study suggests a successful strategy to enhance vascularized bone regeneration by utilizing hypo-sEVs via the miR-210-3p/EFNA3/PI3K/AKT pathway. STATEMENT OF SIGNIFICANCE: Considering the significance of vascularization in ideal bone regeneration, strategies to promote angiogenesis during bone repair are required. Hypoxia microenvironment can promote the proangiogenic potential of mesenchymal stem cells (MSCs). Nonetheless, the therapeutic effect of small extracellular vesicles (sEVs) from hypoxia-preconditioned MSCs on cranio-maxillofacial bone defect remains unknown, and the underlying mechanism is poorly understood. This study shows that hypo-sEVs significantly enhance the proliferation, migration, and angiogenesis of HUVECs as well as promote vascularized bone formation. Moreover, this work indicates that HIF-1α can induce overexpression of miR-210-3p under hypoxia, and miR-210-3p can hinder EFNA3 expression and subsequently activate the PI3K/AKT pathway. The application of hypo-sEVs provides a facile and promising strategy to promote vascularized bone regeneration in a critical-size bone defect model.

Interpositional arthroplasty of post-traumatic temporomandibular joint ankylosis: A modified method.

The purpose of this study was to evaluate a modified method of interpositional arthroplasty for post-traumatic temporomandibular joint ankylosis. All patients were treated with a modified interpositional arthroplasty that included: navigation-assisted accurate bone dissection with minimal removal of only 5 mm of the ankylosed bony mass, novel application of bone wax and porcine acellular dermal matrix to prevent re-ankylosis, and a unique 3D-printed splint for occlusal stabilization and gap maintaining. The pre- and post-operative physical and radiological examinations of patients were recorded during routine follow-up visits. Postoperative follow-up visits lasted at least 12 months. Twelve patients, seven males and five females, ranging from 21 years to 59 years, were enrolled in this retrospective case series. All of the twelve patients with eighteen bony ankylosed temporomandibular joints were treated by our new method. The post-operative follow-up periods ranged from 1 year to 4 years. During the follow-up visits within at least 1 year, no one manifested re-ankylosis. The mean maximum incisor opening changed from 7.4 ± 5.3 mm (p < 0.001, before surgery) to 37.6 ± 3.9 mm (p < 0.001, last follow-up visit). No sign of post-operative infection or foreign body rejection was observed during the follow-up visits. The post-operative occlusal relationship was sound and stable. It is suggested that the modified method of interpositional arthroplasty provides favorable clinical and radiographic outcomes after a short-term follow up.

Experimental and clinical evaluation of BMP2-CPC graft versus deproteinized bovine bone graft for guided bone regeneration: A pilot study.

In this study, we proposed BMP2-incorporated calcium phosphate cement (BMP2-CPC), for application in guided bone regeneration (GBR) and compared the experimental bone restoration performance and clinical alveolar bone reconstruction outcome of BMP2-CPC with those of deproteinized bovine bone (DBB). The animal study indicated that, compared to DBB, which induced the slow ingrowth of new bone, BMP2-CPC induced numerous small growth centers for bone regeneration and facilitated a significant amount of bone regeneration in rabbit calvarial bone defects. Fewer residual graft particles remained in the BMP2-CPC-treated defects than in the DBB-treated defects. The clinical study indicated that BMP2-CPC was similar to DBB in remedying alveolar bone insufficiency and maintaining implant stability. In conclusion, the results of this present study indicate that compared to DBB, BMP2-CPC can significantly enhance in vivo bone regeneration and remodeling in rabbit calvarial bone defects and shows preliminary support on its clinical application in GBR surgeries.

Improved BMP2-CPC-stimulated osteogenesis in vitro and in vivo via modulation of macrophage polarization.

This study aimed to explore the in vitro and in vivo roles of macrophages in the osteogenesis stimulated by BMP2-CPC. In vitro, the alteration of macrophage polarization and cytokine secretion induced by BMP2-CPC or CPC was investigated. The influence of conditioned medium derived from BMP2-CPC- or CPC-stimulated macrophages on the migration and osteogenic differentiation of MSCs were evaluated. The in vivo relationship between macrophage polarization and osteogenesis was examined in a rabbit calvarial defect model. The in vitro results indicated that BMP2-CPC and CPC induced different patterns of macrophage polarization and subsequently resulted in distinct patterns of cytokine expression and secretion. Conditioned medium derived from BMP2-CPC- or CPC-stimulated macrophages both exhibited apparent osteogenic effect on MSCs. Notably, BMP2-CPC induced more M2-phenotype polarization and higher expression of anti-inflammatory cytokines and growth factors than did CPC, which led to the better osteogenic effect of conditioned medium derived from BMP2-CPC-stimulated macrophages. The rabbit calvarial defect model further confirmed that BMP2-CPC facilitated more bone regeneration than CPC did by enhancing M2-phenotype polarization in local macrophages and then alleviating inflammatory reaction. In conclusion, this study revealed that the favorable immunoregulatory property of BMP2-CPC contributed to the strong osteogenic capability of BMP2-CPC by modulating macrophage polarization.

The Transcription Factor Foxc1 Promotes Osteogenesis by Directly Regulating Runx2 in Response of Intermittent Parathyroid Hormone (1-34) Treatment.

Parathyroid hormone (PTH) is crucial for bone remodeling. Intermittent PTH (1-34) administration stimulates osteogenesis and promotes bone formation; however, the possible targets and underlying mechanisms still remain unclear. In this study, functional links between PTH and Foxc1, a transcription factor reported to be predominant in skeletal development and formation, were indicated. We determined the impacts of Foxc1 on in vitro osteogenic differentiation and in vivo bone regeneration under intermittent PTH induction, and further explored its possible targets. We found that the expression level of Foxc1 was upregulated during osteogenic induction by intermittent PTH treatment, and the elevated expression of Foxc1 induced by PTH was inhibited by PTH1R silencing, while rescued by intermittent PTH supplement. By gain- and loss-of-function strategies targeting Foxc1 in MC3T3-E1 cells, we demonstrated that Foxc1 could promote in vitro osteogenic differentiation by intermittent PTH induction. Moreover, immunofluorescence analysis indicated the nuclear co-localization of Foxc1 with Runx2. Luciferase-reporter and chromatin immunoprecipitation analysis further confirmed that Foxc1 could bind to the P1 promoter region of Runx2 directly, which plays an indispensable part in osteogenic differentiation and bone mineralization. Meanwhile, we also revealed that Foxc1 could promote bone regeneration induced by intermittent PTH treatment in vivo. Taken together, this study revealed the role and mechanism of Foxc1 on in vitro osteogenic differentiation and in vivo bone regeneration in response of intermittent PTH treatment.

Effects of inferior alveolar nerve rupture on bone remodeling of the mandible: A preliminary study.

Although various animal studies have indicated that sensory nerves played an important role in bone metabolism and nerve injury could impair the process of bone remodeling, the actual effect of sensory nerve rupture on human bones remains unclear. The aim of this preliminary study was to investigate the effect of inferior alveolar nerve (IAN) rupture on mandibular bone remodeling of patients underwent bilateral sagittal split ramus osteotomy (BSSRO).Ten patients with unilateral IAN rupture during BSSRO were involved in this study. Neurosensory examinations were employed to assess the sensory function of bilateral IAN. The remodeling process of the post-operational mandible was evaluated by panoramic radiographs and computed tomography (CT) scans.Neurosensory examinations indicated that nerve rupture resulted in significant hypoesthesia at the IAN-rupture side. Assessment of panoramic radiographs showed no evident alterations of bone structure at the IAN-rupture side of mandible. Evaluation of CT images also indicated no statistical difference in bone density and thickness between IAN-rupture side and contralateral side.Accordingly, our study indicated that IAN rupture may not significantly impair the short-term bone remodeling process of human mandible.

3D bioprinting and in vitro study of bilayered membranous construct with human cells-laden alginate/gelatin composite hydrogels.

Extrusion-based 3D bioprinting of cell-laden hydrogels is a potential technology for regenerative medicine, which enables the fabrication of constructs with spatially defined cell distribution. However, the limited assessment of rheological behaviors of hydrogel before printing is still a major issue for the advancement of 3D bioprinting. In this work, we systematically investigated the rheological behaviors (i.e. viscosity, storage modulus (G'), and loss modulus (G")) of alginate/gelatin composite hydrogels first for 3D printing complex constructs. The rheological studies revealed that viscosity of alginate/gelatin hydrogels is temperature-dependent and shear thinning. Sol-gel transition (intersection of G' and G") study provided indication for printing temperature, which are in the range of 18.8 °C (H2/7.5) to 24.5 °C (H2/24.5). The alginate (2 wt%) /gelatin (15 wt%) composite hydrogel sample was chosen to print the constructs and subsequent bioprinting. Complex constructs (i.e. nose and ear) were obtained with high printing resolution (151 ±â€¯13.04 µm) in a low temperature (4 °C) chamber and crosslinking with 2 wt% CaCl2 subsequently without extra supports. Human amniotic epithelial cells (AECs) showed superior potential to differentiate into epithelial cells, while Wharton's jelly derived mesenchymal stem cells (WJMSCs) showed a superior angiogenic potential and fibroblastic phenotype. For the in vitro study, AECs and WJMSCs as seed cells, encapsulated in alginate/gelatin composite hydrogels, were bioprinted to form biomimetic bilayered membranous construct. High cell viability (> 95%) were observed up to 6 days after printing. The presented 3D bioprinting of human AECs and WJMSCs-laden alginate/gelatin composite hydrogels provides promising potentials for future skin tissue engineering.