No abstract

In order to explore the abilities of an integrated three‐dimensional micro‐nano topography in immunomodulation and promoting bone formation, present study focuses on the titanium sheets used in the micro‐nano topography by treating them with the sandblasted, large‐grit and acid‐etched (SLA)and alkaline thermal reaction. Further, we characterized and obtained the surface morphology, roughness, and hydrophilicity of the titanium sheets. Moreover, we detected their in vitro cytocompatibility and cell proliferation as well. In addition, investigation was carried out for the immunomodulatory ability of the titanium sheets in a micro‐nano topography by observing the expression of M1 (classical activated macrophage) and M2 (alternatively activated macrophage) type marker factors, inflammatory factors, and morphological changes of RAW264.7 cells cultured on the titanium sheets in different topographies. Through cell migration experiments and coculture, we observed the effects of different titanium sheet immune environments on osteoblast migration, extracellular matrix mineralization, and osteoblast gene expression. These results showed that the micro‐nano topography constructed through SLA and alkaline thermal treatment improved the hydrophilicity and promoted the cell proliferation. Moreover, it promoted RAW264.7 cells to polarize as M2 phenotype, thereby leading to the anti‐inflammatory effect of local microenvironments. This facilitated osteoblasts to secrete bone morphogenetic protein‐2 (BMP2) and vascular endothelial growth factor. Nonetheless, these findings provided a theoretical basis for the molecular biological mechanism related to implants in a micro‐nano topography which promoted the osteointegration while offering a meaningful theoretical basis for the clinical treatment of such implants.

Our previous study has proved that the up-regulation of glial glutamate transporter 1 (GLT-1) played an important role in the acquisition of brain ischemic tolerance after cerebral ischemic preconditioning (CIP) in rats. However, little is known about the mechanism involved in the up-regulation of GLT-1 in the process. The present study investigates whether p38 MAPK, ERK1/2, and/or JNK participates in the up-regulation of GLT-1 during the induction of brain ischemic tolerance by CIP. It was found that CIP significantly enhanced the expression of p-p38 MAPK without altering p-ERK1/2 and p-JNK expression in the CA1 hippocampus. Inhibition of p38 MAPK function by its selective inhibitor SB203580 or knockdown p38 MAPK expression by its antisense oligodeoxynucleotides (AS-ODNs) suppressed the induction of brain ischemic tolerance. Furthermore, p38 MAPK was activated earlier than the up-regulation of GLT-1 in the CA1 hippocampus after CIP. Meanwhile, the expression of p-p38 MAPK by astrocytes was increased, and p38 MAPK AS-ODNs dose-dependently inhibited the up-regulation of GLT-1 after CIP. Taken together, it could be concluded that p38 MAPK participates in the mediation of GLT-1 up-regulation during the induction of brain ischemic tolerance after CIP.

Background: In this study, we conducted a quantitative analysis of the clinical parameters of crown and gingival morphology (CGM) of the maxillary anterior teeth (MAT). We also analyzed the correlation of these parameters with periodontal biotype (PB), with a view to providing objective standards for PB diagnosis. Methods: The three-dimensional (3D) maxillary digital models of 56 individuals were obtained using an intra-oral scanner. The following parameters were measured with the SpaceClaim software: gingival angle (GA), papilla width (PW), papilla height (PH), crown length (CL), crown width (CW), crown width/crown length ratio (CW/CL), buccolingual width of the crown (BLW), contact surface width (CSW), and contact surface height/crown length ratio (CS/ CL). The PB were determined based on the transparency of the periodontal probe through the gingival sulcus. Independent factors influencing PB were analyzed by logistic regression, and the optimal cutoff values for the independent influencing factors were analyzed using receiver operating characteristic curves (ROC curves). Results: There was no significant difference in the parameters of CGM of the MAT at the left and right sides. The thick biotype accounted for 69.6%, and the parameters of GA, PW, PH, CW, CW/CL and CS/CL were significantly correlated with PB (P ≤ 0.2). GA (odds ratio (OR) = 1.206) and PW (OR = 5.048) were identified as independent predictive factors of PB, with areas under the ROC curve (AUC) of 0.807 and 0.881, respectively, and optimal cutoff values of 95.95°and 10.01 mm, respectively. Conclusion: The CGMs of the MAT at the left and right side are symmetrical. The thin biotype accounts for a small proportion, and GA and PW are independent influencing factors of PB. GA of 95.95°and PW of 10.01 mm are the optimal cutoff values for categorization of individuals as thick biotype. This indicates that when the GA and PW of the right maxillary central incisor are G ≥ 95.95°and ≥ 10.01 mm, respectively, there is a higher probability that these individuals will be categorized as thick biotype.

Osteoimmunity plays an important role in the process of implant osseointegration. Autophagy is a conservative metabolic pathway of eukaryotic cells, but whether the interaction between autophagy and osteoimmunity plays a key role in osseointegration remains unclear. In this study, we prepared smooth titanium disks and micro-nano topography titanium disks, to study the immune microenvironment of RAW264.7 cells, and prepared the conditioned medium to study the effect of immune microenvironment on the osteogenesis and autophagy of MC3T3-E1 cells. Autophagy inhibitor 3-MA was used to inhibit autophagy to observe the change of expression of osteogenic markers. The results showed that the micro-nano topography titanium disks could stimulate RAW264.7 cells to differentiate into M2 type, forming an anti-inflammatory immune microenvironment; compared with the control group, the anti-inflammatory immune microenvironment promoted the proliferation and differentiation of osteoblasts better. The anti-inflammatory immune environment activated the autophagy level of osteoblasts, while the expression of osteogenic markers was down-regulated after inhibition of autophagy. These results indicate that anti-inflammatory immune microenvironment can promote cell proliferation and osteogenic differentiation, autophagy plays an important role in this process. This study further explains the mechanism of implant osseointegration in osteoimmune microenvironment, and provides reference for improving implant osseointegration.

No abstract

Exosomes are nanoscale extracellular vesicles. Several studies have shown that exosomes participate in intercellular communication and play a key role in osseointegration. However, it is unclear whether exosomes and their contents participate in the communication between the immune and skeletal systems in the process of osseointegration. In this study, we obtained smooth titanium disks by polishing and small-scale topography titanium disks by sandblasted large-grit acid-etched (SLA) technology combined with alkali thermal reaction. After stimulating mouse RAW264.7 cells with these two kinds of titanium disks, we co-cultured the MC3T3-E1 cells and the RAW264.7 cells, obtained and identified the exosomes derived from RAW264.7 cells, and studied the effect of the osteoimmune microenvironment and the exosomes on the osseointegration of mouse MC3T3-E1 cells. Cell counting kit-8 (CCK-8), real time quantitative PCR, western blotting, alizarin red staining, and quantitative and confocal fluorescence microscopy were used to study the effects of exosomes on MC3T3-E1 cells; RNA sequencing and correlation analysis were performed. We found that the osteoimmune microenvironment could promote the osseointegration of MC3T3-E1 cells. We successfully isolated exosomes and found that RAW264.7 cell-derived exosomes can promote osteogenic differentiation and mineralization of MC3T3-E1 cells. Through RNA sequencing and gene analysis, we found differentially expressed microRNAs that targeted the signal pathways that may be related, such as mTOR, AMPK, Wnt, etc., and thus provide a reference for the mechanism of osteoimmunue regulation of implant osseointegration. The study further elucidated the mechanism of implant osseointegration and provided new insights into the effect of exosomes on implant osseointegration, and provided reference for clinical improvement of implant osseointegration and implant success rate.

Background : In this study, we conducted a quantitative analysis of the clinical parameters of crown and gingival morphology (CGM) of the maxillary anterior teeth (MAT). We also analyzed the correlation of these parameters with periodontal biotype (PB), with a view to providing objective standards for PB diagnosis. Methods : The three-dimensional (3D) maxillary digital models of 56 individuals were obtained using an intra-oral scanner. The following parameters were measured with the SpaceClaim software: gingival angle (GA), papilla width (PW), papilla height (PH), crown length (CL), crown width (CW), crown width/crown length ratio (CW/CL), bucco-lingual width of the crown (BLW), contact surface width (CSW), and contact surface height/crown length ratio (CS/CL). The PB were determined based on the transparency of the periodontal probe through the gingival sulcus. Independent factors influencing PB were analyzed by logistic regression, and the optimal cutoff values for the independent influencing factors were analyzed using receiver operating characteristic curves (ROC curves). Results : There was no significant difference in the parameters of CGM of the MAT at the left and right sides. The thick biotype accounted for 69.6%, and the parameters of GA, PW, PH, CW, CW/CL and CS/CL were significantly correlated with PB ( P ≤ 0.2). GA (odds ratio (OR) = 1.206) and PW (OR = 5.048) were identified as independent predictive factors of PB, with areas under the ROC curve (AUC) of 0.807 and 0.881, respectively, and optimal cutoff values of 95.95° and 10.01 mm, respectively. Conclusion: The CGMs of the MAT at the left and right side are symmetrical. The thin biotype accounts for a small proportion, and GA and PW are independent influencing factors of PB. GA of 95.95° and PW of 10.01 mm are the optimal cutoff values for categorization of individuals as thick biotype. This indicates that when the GA and PW of the right maxillary central incisor are G ≥95.95° and ≥10.01 mm, respectively, there is a higher probability that these individuals will be categorized as thick biotype.