SHED-derived exosomes improve the repair capacity and osteogenesis potential of hPDLCs.

OBJECTIVE: Exosomes secreted by stem cells are recognized as a critical component in tissue regeneration during stem cell-based therapy. Considering the limited sources and bone regeneration efficiency of human periodontal ligament cells (hPDLCs), we explored whether exosomes secreted by stem cells from human exfoliated deciduous teeth (SHED-exo) could improve the pluripotency and regenerative potential of hPDLCs. METHODS AND MATERIALS: In hPDLCs, cell proliferation, migration, cell cycle, apoptosis, and osteogenic differentiation were detected after cells were exposed to SHED-exo (SHED-exo group), blank (control group), or control supernatant without exo (Csup group), via CCK-8, scratch analysis, flow cytometric, real-time PCR, and so on. Exosomes sequencing was performed to compare and analyze miRNAs contented in SHED-exo and hPDLC-exo. RESULTS: As compared to control or Csup, SHED-exo significantly increased migration, apoptosis, and proliferation, promoted cell cycle transition from G1 to S phase in hPDLCs, and enhanced Runx2 expression and mineralization. In addition, it may be explained by the significant differences in miRNA contented in SHED-exo and hPDLC-exo. CONCLUSION: Exosomes from SHED can improve cell proliferation, migration, cell cycle, apoptosis, and osteogenic differentiation of hPDLCs, which highlights the therapeutic value of this bioactive component in the regeneration of periodontal tissues using hPDLCs in clinical practice.

C-reactive protein perturbs alveolar bone homeostasis: An experimental study of periodontitis and diabetes in the rat.

AIM: To explore the role of C-reactive protein (CRP) in periodontitis and diabetes and its mechanism in alveolar bone homeostasis. MATERIALS AND METHODS: In vivo, normal, and Crp knockout (KO) rats were randomly divided into control, diabetes, periodontitis, and diabetes and periodontitis groups, respectively. The diabetes model was established using a high-fat diet combined with streptozotocin injection. The periodontitis model was established by ligature combined with lipopolysaccharide (LPS) injection. Alveolar bones were analysed using micro-computed tomography, histology, and immunohistochemistry. In vitro, human periodontal ligament cells (hPDLCs) were treated with LPS and high glucose. CRP knockdown lentivirus or CRP overexpression adenovirus combined with a PI3K/AKT signalling inhibitor or agonist were used to explore the regulatory mechanism of CRP in osteogenesis and osteoclastogenesis of hPDLCs, as evidenced by alkaline phosphatase staining, Western blot, and quantitative polymerase chain reaction. RESULTS: In periodontitis and diabetes, CRP KO decreased the alveolar bone loss and the expression levels of osteoclastogenic markers, while increasing the expression levels of osteogenic markers. CRP constrained osteogenesis while promoting the osteoclastogenesis of hPDLCs via PI3K/AKT signalling under high glucose and pro-inflammatory conditions. CONCLUSIONS: CRP inhibits osteogenesis and promotes osteoclastogenesis via PI3K/AKT signalling under diabetic and pro-inflammatory conditions, thus perturbing alveolar bone homeostasis.

Prevalence and associated factors for temporomandibular disorders in Chinese civilian pilots.

PURPOSE: Piloting is a special profession with prolonged stress, which could induce the occurrence of TMD. This sample is useful to reduce the effect of confounders in the analyses. Based on this, the present study aims to determine the prevalence and associated factors for TMD in civilian pilots of China. METHODS: A cross-sectional epidemiological survey was carried out in 616 male subjects (aged 23-52 years). The questionnaire included general information, chewing preference (bilateral or unilateral), and Trait Anxiety section of Spielberger State-Trait Anxiety Inventory (STAI-T). The clinical examination contained TMD screening per research diagnostic criteria for TMD and diagnosis of sleep bruxism per American Academy of Sleep Medicine standards. The level of statistical significance was set at P ≤ 0.05. RESULTS: The program was conducted from June 2012 to April 2013, in which period, and the percentage of TMD in the samples we examined was 33.3 % (=205/616). Only high anxiety (OR 2.48; 95 % CI 1.25-4.90) and unilateral chewing preference (OR 12.67; 95 % CI 7.77-20.65) were the most significant associated factors with TMD. Also, salivary cortisol and the STAI-T score had a significant correlation (r = 0.47, P < 0.001). CONCLUSIONS: It was more reliable to study the associated factors on TMD with the exclusion of the possible confounding factors, and only unilateral chewing preference and psychological stress had a significant association with TMD. In addition, the salivary cortisol levels might assist to assess psychological stress in epidemiological research.

An injectable porous bioactive magnesium phosphate bone cement foamed with calcium carbonate and citric acid for periodontal bone regeneration.

Magnesium phosphate cement (MPC) has been evaluated as a novel bone substitute owing to its favorable biocompatibility, plasticity, and osteogenic potential. However, the low porosity of MPC prevents growth factors and osteoblasts from fully growing into the material, thereby limiting its clinical use. In this study, different concentrations (0-5%) of calcium carbonate and citric acid (CA) were used as foaming agents to prepare porous MPC. The MPC containing 3% CaCO3/CA exhibited the best physicochemical properties, including greater porosity, improved injectability, extended setting time, and decreased hydration temperature. The proliferation and adhesion of cells on 3%CaCO3/CA-MPC were higher than those on MPC alone. To explore its osteogenesis in vivo, 3% CaCO3/CA-MPC and Bio-Oss® bone powder were implanted into periodontal bone defects in rats for 4 weeks and 12 weeks, respectively. Micro-CT and histological analysis demonstrated the improved bone regeneration of 3%CaCO3/CA-MPC compared to the blank group (P < 0.05); it had slightly lower bone regeneration than the Bio-Oss® group but no statistical difference. The results indicated that porous MPC foamed with calcium carbonate and CA improved its physicochemical properties and enhanced its biocompatibility, making it a promising material for bone regeneration.

Extracellular vesicles derived from human dental mesenchymal stem cells stimulated with low-intensity pulsed ultrasound alleviate inflammation-induced bone loss in a mouse model of periodontitis.

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have emerged as a new mode of intercellular crosstalk and are responsible for many of the therapeutic effects of MSCs. To promote the application of MSC-EVs, recent studies have focused on the manipulation of MSCs to improve the production of EVs and EV-mediated activities. The current paper details an optimization method using non-invasive low-intensity pulsed ultrasound (LIPUS) as the stimulation for improving oral MSC-EV production and effectiveness. Stem cells from apical papilla (SCAP), a type of oral mesenchymal stem cell, displayed intensity-dependent pro-osteogenic and anti-inflammatory responses to LIPUS without significant cytotoxicity or apoptosis. The stimuli increased the secretion of EVs by promoting the expression of neutral sphingomyelinases in SCAP. In addition, EVs from LIPUS-induced SCAP exhibited stronger efficacy in promoting the osteogenic differentiation and anti-inflammation of periodontal ligament cells in vitro and alleviating oral inflammatory bone loss in vivo. In addition, LIPUS stimulation affected the physical characteristics and miRNA cargo of SCAP-EVs. Further investigations indicated that miR-935 is an important mediator of the pro-osteogenic and anti-inflammatory capabilities of LIPUS-induced SCAP-EVs. Taken together, these findings demonstrate that LIPUS is a simple and effective physical method to optimize SCAP-EV production and efficacy.

Low-intensity Pulsed Ultrasound regulates alveolar bone homeostasis in experimental Periodontitis by diminishing Oxidative Stress.

Periodontitis is a widespread oral disease that results in the loss of alveolar bone. Low-intensity pulsed ultrasound (LIPUS), which is a new therapeutic option, promotes alveolar bone regeneration in periodontal bone injury models. This study investigated the protective effect of LIPUS on oxidative stress in periodontitis and the mechanism underlying this process. Methods: An experimental periodontitis model was induced by administering a ligature. Immunohistochemistry was performed to detect the expression levels of oxidative stress, osteogenic, and osteoclastogenic markers in vivo. Cell viability and osteogenic differentiation were analyzed using the Cell Counting Kit-8, alkaline phosphatase, and Alizarin Red staining assays. A reactive oxygen species assay kit, lipid peroxidation MDA assay kit, and western blotting were used to determine oxidative stress status in vitro. To verify the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an oxidative regulator, during LIPUS treatment, the siRNA technique and Nrf2-/- mice were used. The PI3K/Akt inhibitor LY294002 was utilized to identify the effects of the PI3K-Akt/Nrf2 signaling pathway. Results: Alveolar bone resorption, which was experimentally induced by periodontitis in vivo, was alleviated by LIPUS via activation of Nrf2. Oxidative stress, induced via H2O2 treatment in vitro, inhibited cell viability and suppressed osteogenic differentiation. These effects were also alleviated by LIPUS treatment via Nrf2 activation. Nrf2 silencing blocked the antioxidant effect of LIPUS by diminishing heme oxygenase-1 expression. Nrf2-/- mice were susceptible to ligature-induced periodontitis, and the protective effect of LIPUS on alveolar bone dysfunction was weaker in these mice. Activation of Nrf2 by LIPUS was accompanied by activation of the PI3K/Akt pathway. The oxidative defense function of LIPUS was inhibited by exposure to LY294002 in vitro. Conclusions: These results demonstrated that LIPUS regulates alveolar bone homeostasis in periodontitis by attenuating oxidative stress via the regulation of PI3K-Akt/Nrf2 signaling. Thus, Nrf2 plays a pivotal role in the protective effect exerted by LIPUS against ligature-induced experimental periodontitis.

Proteomics and N-glycoproteomics analysis of an extracellular matrix-based scaffold-human treated dentin matrix.

Extracellular matrix (ECM)-based biomaterials developed from mammalian tissues have been successfully used in preclinical and clinical tissue engineering applications. We have previously reported about the applicability of dentin-based scaffold, treated dentin matrix (TDM), for tooth root regeneration. However, TDM protein composition has not been characterized. Here, we used a shotgun proteomic strategy to profile human TDM proteome. N-glycoproteins were enriched by lectin affinity chromatography and identified by mass spectrometry. The total human TDM proteome was compared with the previously published human dentin proteome, and bioinformatics analysis were performed accordingly. In total, 708 proteins were identified by mass spectrometry in human TDM, of which 208 were N-glycoproteins with 318 identified glycosylation sites. Collagens, proteoglycans, small integrin-binding ligand N-linked glycoproteins (SIBLINGs), and growth factors, such as COL1A1, biglycan, dentin sialoprotein, and transforming growth factor beta 1, were identified. Glycoproteins were enriched in "biological processes" Gene Ontology terms such as cellular process, biological regulation, response to stimulus, metabolic process, immune system process, and biological adhesion. Thus, our comprehensive study of the human TDM proteome revealed that dentin proteins are more heterogeneous than previously documented. Our findings provide clues for designing new biomaterials for tooth root regeneration and understanding dentin formation.

A Morphometric Study of Labial Grooves on Anterior Maxillary Dentition.

This study was performed to investigate the shape, characteristics, and correlation of labial grooves on anterior maxillary dentition. Individual teeth (N = 621) were investigated using a microscopic three-dimensional digital image correlation system. The average length, width, and depth of grooves were quantified, and groove patterns in anterior maxillary teeth and the symmetry and correlation of grooves in anterior maxillary dentition were studied. There were nine common groove patterns in central incisors, eight in lateral incisors, and nine in canines. A good symmetry of grooves was found between the left and right dentition. The number of grooves and the groove pattern were correlated among central incisors, lateral incisors, and canines. This study may provide guidance for clinical design of labial grooves.

Metabolic Syndrome and Periodontal Disease Among Civilian Pilots.

BACKGROUND: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that can affect civilian pilots' health. Its prevalence and the correlation with periodontal disease (PD) among pilots had not been previously reported. The aim of the study was to determine MetS and PD status, and to reveal their relationship in a representative sample of Chinese civilian pilots. METHODS: We investigated 303 civilian pilots (mean age 34.92 ± 7.66 yr). General information as well as blood and saliva samples were collected. Diagnostic criteria for MetS were based on the joint interim statements of several medical organizations. Periodontal status was evaluated by Community Periodontal Index (CPI). Measurements included body mass index (BMI), waist circumference (WC), blood pressure (BP), concentration of serum high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), fasting plasma glucose (FPG), saliva matrix metalloproteinase-8, and tissue inhibitors of matrix metalloproteinase-1 (TIMP-1). RESULTS: Of the subjects, 38.28% showed MetS and 23.10% showed periodontitis. Significant differences were found between the MetS and non-MetS pilots in total flying hours, CPI, WC, BP, TG, HDL-C, FPG, BMI, and TIMP-1. Significant relationships were found between MetS and CPI, BMI, and TIMP-1. The odds ratios were 3.378 (95%CI: 1.889-5924) for CPI, 1.269 (95%CI: 1.101-1.463) for BMI, and 0.600 (95%CI: 0.399-0.904) for TIMP-1. CONCLUSION: The prevalence of MetS was sufficiently high to be a matter of medical concern, and was associated with PD among civilian pilots.Chen X, Xie L, Liu Y, Chen D, Yu Q, Gan X, Yu H. Metabolic syndrome and periodontal disease among civilian pilots. Aerosp Med Hum Perform. 2016; 87(12):1016-1020.