Adipogenic differentiation effect of human periodontal ligament stem cell initial cell density on autologous cells and human bone marrow stromal cells.

Stem cells demonstrate differentiation and regulatory functions. In this discussion, we will explore the impacts of cell culture density on stem cell proliferation, adipogenesis, and regulatory abilities. This study aimed to investigate the impact of the initial culture density of human periodontal ligament stem cells (hPDLSCs) on the adipogenic differentiation of autologous cells. Our findings indicate that the proliferation rate of hPDLSCs increased with increasing initial cell density (0.5-8 × 104 cells/cm2). After adipogenic differentiation induced by different initial cell densities of hPDLSC, we found that the mean adipose concentration and the expression levels of lipoprotein lipase (LPL), CCAAT/enhancer binding protein α (CEBPα), and peroxisome proliferator-activated receptor γ (PPAR-γ) genes all increased with increasing cell density. To investigate the regulatory role of hPDLSCs in the adipogenic differentiation of other cells, we used secreted exocrine vesicles derived from hPDLSCs cultivated at different initial cell densities of 50 µg/mL to induce the adipogenic differentiation of human bone marrow stromal cells. We also found that the mean adipose concentration and expression of LPL, CEBPα, and PPARγ genes increased with increasing cell density, with an optimal culture density of 8 × 104 cells/cm2. This study provides a foundation for the application of adipogenic differentiation in stem cells.

Study on nonlinear dynamic characteristics of a two-speed transmission system at low speed.

A pure shear mechanical model of low gear of six-degree-of-freedom two-speed transmission system is established by using lumped parameter method. The Runge-Kutta method is used to numerically solve the aforementioned nonlinear system. The variation of transmission error between gears is analyzed by using global bifurcation, time domain diagram, phase diagram and Poincare cross section. Moreover, the transfer error bifurcation characteristics of the solar wheel and the first planetary wheel under different gear moduli are investigated. The results show that: by taking the excitation frequency as the control parameter, the system includes period-1 motion, period-2 motion, quasi-periodic motion, multiperiodic motion, and chaotic motion. With the increase of gear modulus, the system mainly presents chaotic motion in the medium frequency range (0.5<ωh≤2). It shows stable period-1 motion in the high frequency range (2<ωh≤3), and the higher the modulus, the wider the high frequency range of period-1 motion. The research results can provide reference for the design and optimization of this kind of two-speed transmission system in the future.

LncRNA MALAT1 promotes osteogenic differentiation through the miR-93-5p/SMAD5 axis.

OBJECTIVES: Promoting the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) is a way to regenerate periodontal bone. This study aimed to determine whether lncRNA MALAT1 promotes the osteogenic differentiation of human PDLSCs in vitro. MATERIALS AND METHODS: Human PDLSCs were extracted from the human periodontal ligament, and after osteogenic differentiation was induced using osteogenic medium, the human PDLSCs were transfected with siRNA-MALAT1, miR-93-5p mimics, and miR-93-5p inhibitors. The expression of osteogenesis-related genes was assessed by RT-qPCR and western blotting, alkaline phosphatase (ALP) activity was assessed by ALP activity assay, and the formation of mineralized nodules was assessed by alizarin red S (ARS) staining. RNA immunoprecipitation (RIP) and luciferase assays were performed to assess the binding of MALAT1, miR-93-5p, and SMAD5. RESULTS: The expression of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was upregulated, while that of miR-93-5p was downregulated after PDLSC osteogenic differentiation. Knockdown of MALAT1 inhibited the osteogenic differentiation of PDLSCs, and MALAT1 expression negatively correlated with miR-93-5p expression. miR-93-5p inhibited the osteogenic differentiation of human PDLSCs by specifically binding to SMAD5. CONCLUSION: MALAT1 regulates human PDLSC differentiation by regulating the miR-93-5p/SMAD5 axis.

CpG ODN/Mangiferin Dual Delivery through Calcium Alginate Hydrogels Inhibits Immune-Mediated Osteoclastogenesis and Promotes Alveolar Bone Regeneration in Mice.

The immune system plays an important role in the skeletal system during bone repair and regeneration. The controlled release of biological factors from the immune system could facilitate and optimize the bone remodeling process through the regulation of the activities of bone cells. This study aimed to determine the effect of the controlled delivery of immunomodulatory biologicals on bone regeneration. Immunostimulatory cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) and glucosylxanthone Mangiferin (MAG)-embedded microbeads were incubated with P. gingivalis-challenged splenocytes, or co-cultured with RAW264.7 cells. The effect of CpG ODN/MAG-containing microbeads on bone regeneration was then tested in vivo in a mouse alveolar bone defect model. The results demonstrated that MAG significantly antagonized P. gingivalis proliferation and reduced the live/dead cell ratio. After the addition of CpG ODN + MAG microbeads, anti-inflammatory cytokines IL-10 and IL-4 were upregulated on day 2 but not day 4, whereas pro-inflammatory cytokine IL-1ß responses showed no difference at both timepoints. RANKL production by splenocytes and TRAP+ cell formation of RAW264.7 cells were inhibited by the addition of CpG ODN + MAG microbeads. Alveolar bony defects, filled with CpG ODN + MAG microbeads, showed significantly increased new bone after 4 weeks. In summary, this study evaluated a new hydrogel-based regimen for the local delivery and controlled release of biologicals to repair and regenerate alveolar bony defects. The combined CpG ODN + MAG treatment may promote alveolar bone regeneration through the anti-microbial/anti-inflammatory effects and the inhibition of RANKL-mediated osteoclastogenesis.

Osteogenic effect of crocin in human periodontal ligament stem cells via Wnt/ß-catenin signaling.

OBJECTIVES: Crocin is a major class of medicinal components in saffron. This study aimed to determine whether crocin directly promotes the proliferation and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) in vitro and in vivo. MATERIALS AND METHODS: CCK8 cell proliferation assay, reverse transcription quantitative polymerase chain reaction (RT-qPCR), Western blot analysis and Alizarin Red staining were performed in PDLSCs using crocin as a stimulant. DKK1 was used to selectively inhibit Wnt/ß-catenin signaling, and Western blotting was performed to investigate the underlying mechanism. The PDLSCs were mixed with calcium phosphate cement and implanted into nude mice subcutaneously to study the effect of crocin on PDLSC osteogenic differentiation in vivo. RESULTS: The CCK-8 assay showed that crocin did not promote the proliferation of PDLSCs. Treatment with 400 µM crocin significantly promoted PDLSC mRNA levels of ALP, COL1 and OCN; RUNX2 and BMP2 protein expression; mineralized nodule formation in vitro and in vivo; and ALP activity in tissues in vivo. In addition, crocin significantly promoted the phosphorylation of ß-catenin and cyclin D1. DKK1 inhibits Wnt/ß-catenin activation and partially reverses crocin-mediated promotion of PDLSC osteogenic differentiation. CONCLUSION: Crocin may contribute to the regeneration of periodontal bone tissue.

Mangiferin promotes the osteogenic differentiation of human periodontal ligament stem cells via TGF­ß/SMAD2 signaling.

Mangiferin (MAG) is a polyphenolic compound present in mangoes. This compound suppresses inflammation and decreases bone destruction. This study aimed to determine whether MAG directly promotes proliferation and osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). Cell proliferation and osteogenic differentiation experiments were performed in hPDLSCs, and MAG was used as a stimulator during osteogenic induction. Alkaline phosphatase (ALP) activity and Alizarin red staining were analyzed, and the expression of osteogenesis­associated genes was investigated by reverse transcription­quantitative polymerase chain reaction (RT­qPCR) and western blot analysis to determine the effect of MAG on the osteogenic differentiation of hPDLSCs. Galunisertib was used to selectively inhibit TGF­ß/SMAD2 signaling. Western blotting was performed to study the underlying mechanism. Cell Counting Kit­8 assay showed that MAG did not promote the proliferation of hPDLSCs. MAG (200 µM) significantly promoted ALP activity, mRNA levels of alkaline phosphatase biomineralization associated, collagen type 1, and runt­related transcription factor­2, protein levels of SMAD5, alkaline phosphatase and bone morphogenetic protein 2 protein expression and mineralized nodule formation in hPDLSCs. Furthermore, MAG significantly promoted the phosphorylation of SMAD2. Galunisertib inhibited the activation of SMAD2 and partially reversed the MAG­mediated promotion of hPDLSC osteogenic differentiation. These data indicated that MAG promoted osteogenic differentiation of hPDLSCs potentially through TGF­ß/SMAD2 signaling. Therefore, MAG may help improve periodontal bone loss.

Physical Activity Related to Body Muscle Mass Index and Stiffness Index in 7-to-10-Year-Old Girls.

The relationship between moderate-to-vigorous physical activity (MVPA) performance time and body muscle mass and stiffness index in pre-puberty school-aged girls has not been fully elucidated. The effect of sexual maturity on bone mass is more pronounced in girls. This study aimed to clarify the relationship between MVPA performance time and the above-mentioned factors. This was a prospective, population-based cohort study of 111 girls aged 7-10 years. Data were collected via medical examination, clinical measurements, and questionnaires. Spearman's ρ analysis was used to determine the association between skeletal muscle mass index (SMI) and stiffness index, muscle strength, and MVPA performance time. Participants who met the recommended MVPA level accounted for only 24.3% (n = 27) of all participating girls (n = 111). The following factors were significantly positively correlated with MVPA level at spearman's ρ analysis: SMI (r = 0.303, p = 0.001), stiffness index (r = 0.229, p = 0.015), grip strength (r = 0.283, p = 0.003), back muscle strength (r = 0.197, p = 0.038), and standing long jump distance (r = 0.288, p = 0.002). Multiple regression analysis's results revealed that SMI (ß = 0.237; p = 0.024) was associated with MVPA performance time. These results can help school-aged girls to pay adequate attention to having healthy physical activity habits to prevent the decline of skeletal muscle mass, stiffness index, and body muscle strength.

Decreased Balance Function in School-Aged Children with Behavioral Problems.

Children with behavioral problems have a high risk of impaired motor performance. However, the characteristics of balance functions and their associations with behavioral traits are unclear in this population. This study aimed to evaluate balance functions and their relationships with the degree of behavioral problems in school-aged children. A total of 209 children, aged 6-10 years, were divided into two groups, those with and those without behavioral problems, using the Strengths and Difficulties Questionnaire (SDQ). Physical assessments included the one-leg standing test (OLST), the two-step test, and the five-times-sit-to-stand test. We compared the data between groups and assessed for correlations in terms of total difficulties and the SDQ subscale scores. Children with behavioral problems showed significantly reduced the OLST results (p < 0.001) and the two-step test results (p = 0.008). The five-times-sit-to-stand test results did not show significant differences between groups. The OLST results were significantly correlated with emotional symptoms (r = -0.22, p < 0.001), hyperactivity/inattention (r = -0.29, p < 0.001), peer relationship problems (r = -0.22, p < 0.001), and total difficulties (r = -0.32, p < 0.001). Meanwhile, the two-step test results showed no significant correlation with the SDQ scores. Children with behavioral problems have poor balance function, thereby increasing the risk for instability. This suggests that the balance function of children with behavioral problems needs to be considered.

Factors Related to Locomotive Syndrome in School-Aged Children in Okazaki: A Cross-Sectional Study.

The relationship of locomotive syndrome with other physical characteristics and lifestyle habits in children has not been fully elucidated. The aim of this study was to assess the prevalence of children's locomotive syndrome, and to determine its relationship with the above-mentioned factors. This was a cross-sectional study of 285 elementary school children who volunteered to participate in a medical checkup for physical function. Data was collected via medical examination, clinical measurements, and questionnaires. A multivariable logistic regression model was used to determine the relationship (odds ratios; ORs) of participants' characteristics, physical functions, and other outcomes determined by questionnaire on locomotive syndrome. The following factors were related to locomotive syndrome: older age (OR = 1.421, 95% confidence interval [CI] [1.039, 1.945]), male sex (OR = 4.011, 95% CI [2.189, 7.347]), and more time spent watching television per day (OR = 1.281, 95% CI [1.001, 1.640]). These results may assist in the encouragement of children to perform appropriate physical activities and avoid unhealthy lifestyle habits, reducing the occurrence of locomotive syndrome.

Bite Force Transducers and Measurement Devices.

In dental research, bite force has become an important curative effect evaluation index for tooth restoration, periodontal treatment, and orthodontic treatment. Bite force is an important parameter to evaluate the efficacy of the masticatory system. Physicians obtain the therapeutic basis for occlusal adjustment by measuring the bite force and the dynamic changes in occlusal contact at different stages of treatment and objectively evaluate the therapeutic effect. At present, many devices are used to record the bite force. Most of these devices use force transducers to detect bite force, such as strain gauge transducers, piezoresistive transducers, piezoelectric transducers, optical fiber transducers, and pressure-sensitive films. This article summarizes the various equipment used to record bite force, related materials and the characteristics of this equipment. It provides a reference for physicians to make choices during the clinical process and at the same time provides a basis for the development of new occlusal force measurement materials.

A Biphasic Calcium Phosphate Cement Enhances Dentin Regeneration by Dental Pulp Stem Cells and Promotes Macrophages M2 Phenotype In Vitro.

Calcium phosphate cement (CPC) is promising for bone and dentin repair and regeneration. However, there has been no report of biphasic CPC for inducing dentin regeneration. The aim of this study was to develop a novel biphasic CPC containing ß-tricalcium phosphate (ß-TCP), and investigate its effects on odontogenic differentiation of human dental pulp stem cells (hDPSCs) and macrophage polarization. New biphasic CPC was formulated with different ratios of ß-TCP to an equimolar mixture of tetracalcium phosphate and dicalcium phosphate anhydrous. Mechanical properties, biocompatibility, and odontogenic differentiation induction ability of the cements and the inflammatory reaction to the cements were examined. A series of CPC containing ß-TCP were developed. CPC with 20% ß-TCP exhibited homogeneity and injectability, an acceptable setting time, and a twofold increase in compressive strength. Significant increases in hDPSCs' alkaline phosphatase activity, mineral deposit, DMP1 and DSPP gene, and protein expressions were obtained for 20% TCP-CPC, compared with traditional CPC (p < 0.01). The addition of ß-TCP did not promote macrophage polarization to the proinflammation phenotype. The addition of 10% and 20% ß-TCP promoted macrophage polarization to the anti-inflammatory phenotype. In conclusion, a biphasic ß-TCP-modified CPC was developed for the first time, demonstrating substantially increased dentin regeneration capability, while promoting macrophages to an anti-inflammation phenotype. The novel biphasic CPC is promising for tooth tissue engineering and dentin regeneration applications. Impact statement Dental pulp exposure from dental caries, wounds, or deep cavity preparation can cause pain and infection, which may lead to root canal treatment or tooth extraction. Maintaining pulp vitality is a major challenge in stomatology. We developed a new injectable ß-tricalcium phosphate (ß-TCP)-calcium phosphate cement (CPC) for the regeneration of dentin. Compared with traditional CPC, the new CPC +20%TCP possessed good cytocompatibility, acceptable injection force, higher compressive strength (increased by 63%), and greater odontogenic expression and mineral deposits (increased by more than twofolds), while avoiding any proinflammatory drawback. This new biphasic CPC is promising for dental pulp-capping, base, and liner applications to promote dentin regeneration, as well as potentially for bone tissue engineering applications, which warrant further studies.

Toll-Like Receptor Signaling and Immune Regulatory Lymphocytes in Periodontal Disease.

Periodontitis is known to be initiated by periodontal microbiota derived from biofilm formation. The microbial dysbiotic changes in the biofilm trigger the host immune and inflammatory responses that can be both beneficial for the protection of the host from infection, and detrimental to the host, causing tissue destruction. During this process, recognition of Pathogen-Associated Molecular Patterns (PAMPs) by the host Pattern Recognition Receptors (PRRs) such as Toll-like receptors (TLRs) play an essential role in the host-microbe interaction and the subsequent innate as well as adaptive responses. If persistent, the adverse interaction triggered by the host immune response to the microorganisms associated with periodontal biofilms is a direct cause of periodontal inflammation and bone loss. A large number of T and B lymphocytes are infiltrated in the diseased gingival tissues, which can secrete inflammatory mediators and activate the osteolytic pathways, promoting periodontal inflammation and bone resorption. On the other hand, there is evidence showing that immune regulatory T and B cells are present in the diseased tissue and can be induced for the enhancement of their anti-inflammatory effects. Changes and distribution of the T/B lymphocytes phenotype seem to be a key determinant of the periodontal disease outcome, as the functional activities of these cells not only shape up the overall immune response pattern, but may directly regulate the osteoimmunological balance. Therefore, interventional strategies targeting TLR signaling and immune regulatory T/B cells may be a promising approach to rebalance the immune response and alleviate bone loss in periodontal disease. In this review, we will examine the etiological role of TLR signaling and immune cell osteoclastogenic activity in the pathogenesis of periodontitis. More importantly, the protective effects of immune regulatory lymphocytes, particularly the activation and functional role of IL-10 expressing regulatory B cells, will be discussed.

Optimization of clinically applied orthodontic archwire electrothermal treatment conditions by heat tint and mechanical properties: An experimental study.

OBJECTIVE: Electric resistance heat treatment procedures are performed by most orthodontists; however, the effects of electrothermal treatment on the mechanical properties, surface morphology, phase transition, colour and arch width of stainless steel archwires remain controversial and are worthy of investigation. MATERIALS AND METHODS: Stainless steel archwires (0.017×0.025 and 0.019×0.025 inches) were heat-treated using a spot-welder machine at a power setting of 3 for 5, 10, 15 or 20s and were then cooled in air. After the heat treatment, we analysed the surface morphology of the samples by scanning electron microscopy (SEM) and the flexural modulus with a universal testing machine. The changes in phase and the austenite content after heat treatment were determined by X-ray diffraction (XRD). The changes in the colour of the sample were analysed by a digital single-lens reflex (DSLR) camera, and the arch width changes were measured with Vernier calippers. RESULTS: The flexural modulus and austenite content of the orthodontic stainless steel archwires increased after heat treatment (P<0.05). The colour changed from silver to yellow-brown-blue. Heat treatment of the stainless steel wires increased the inter-canine and inter-molar widths only when the amount of heat received was low. CONCLUSION: Heat treatment of stainless steel orthodontic archwires using an electric resistance device is an effective and convenient method to improve their flexural modulus. The colour of the wire surface after heat treatment can help determine the heating conditions, and the maximum flexural modulus of the stainless steel wires was obtained when the colour changed to brownish yellow.

Osteogenic stimulation of human dental pulp stem cells with self-setting biphasic calcium phosphate cement.

Calcium phosphate cement (CPC) is widely used as a repair material for bone defects. However, there is no report on the use of biphasic CPC combined with dental pulp stem cells (DPSCs) for bone tissue engineering. The aim of this study was to construct biphasic CPC and to investigate its effect in the osteogenic stimulation of human DPSCs (hDPSCs) and macrophage polarization. Biphasic CPC was developed by adding different ratios of ß-TCP to an equimolar mixture of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). The biocompatibility, osteogenic capacity, and inflammatory reactions of the cements were examined. Our results show that biphasic CPC containing both HA and ß-TCP was successfully fabricated. The addition of ß-TCP did not increase necrosis or apoptosis of DPSCs. Significant increases in hDPSC mineral deposition and osteogenic marker (ColI and ALP) expression were observed in 20% TCP-CPC. The addition of ß-TCP did not promote macrophage polarization to a proinflammatory phenotype. In conclusion, biphasic CPC with hDPSCs for bone regeneration was developed for the first time; the biphasic CPC combined with hDPSCs is expected to be used for the repair and regeneration of bone.

Osteogenic stimulation of human dental pulp stem cells with a novel gelatin-hydroxyapatite-tricalcium phosphate scaffold.

The aim of the present study was to construct and compare gelatin-HA-TCP scaffolds with a gelatin-only scaffold and to investigate the effect of the scaffold on osteogenic differentiation of human dental pulp stem cells. We developed a novel scaffold for bone tissue engineering via a solution casting/particle washing method, and the physical and mechanical properties of the scaffolds were examined using scanning electron microscopy and a universal testing machine, respectively. Scaffold cytotoxicity toward human dental pulp stem cells (hDPSCs) was evaluated with the CCK8 method, and hDPSC differentiation was evaluated with an alkaline phosphatase activity assay, alizarin red S staining, and reverse transcription-polymerase chain reaction (RT-PCR). Our results indicate that the gelatin-HA-TCP scaffolds exhibited good homogeneity, interconnected pores, and relatively high mechanical strength and water absorption rates. A significant increase in hDPSC proliferation and ALP activity that stimulated mineralization of the hDPSC-generated matrix was also seen on gelatin-HA-TCP scaffolds compared with the gelatin-only scaffolds. In addition, RT-PCR revealed that the gelatin-HA-TCP scaffold upregulated gene expression of the osteogenic markers Runx2, bone sialoprotein, and OSX. In conclusion, gelatin-HA-TCP scaffolds presented better mechanical properties, cytocompatibility and differentiation-inducing characteristics than gelatin scaffolds. These results indicate that the novel hydrogel gelatin-HA-TCP scaffolds may be a promising biomaterial for bone tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1851-1861, 2018.