Gingival Cells Research Articles

Advances in combined application of dental stem cells and small-molecule drugs in regenerative medicine.

Teeth are a kind of masticatory organs of special histological origin, unique to vertebrates, playing an important role in chewing, esthetics, and auxiliary pronunciation. In the past decades, with the development of tissue engineering and regenerative medicine, the studies of mesenchymal stem cells (MSCs) gradually attracted the interest of researchers. Accordingly, several types of MSCs have been successively isolated in teeth or teeth-related tissues, including dental pulp stem cells, periodontal ligament stem cells, stem cells from human exfoliated deciduous teeth, dental follicle stem cells, stem cells from apical papilla and gingival mesenchymal stem cells. These dental stem cells (DSCs) are easily accessible, possess excellent stem cell characteristics, such as high proliferation rates and profound immunomodulatory properties. Small-molecule drugs are widely used and show great advantages in clinical practice. As research progressed, small-molecule drugs are found to have various complex effects on the characteristics of DSCs, especially the enhancement of biological characteristics of DSCs, which has gradually become a hot issue in the field of DSCs research. This review summarizes the background, current status, existing problems, future research directions, and prospects of the combination of DSCs with three common small-molecule drugs: aspirin, metformin, and berberine.

Cellular composition modifies the biological properties and stability of platelet rich plasma membranes for tissue engineering.

Scaffolds should provide structural support for tissue regeneration, allowing their gradual biodegradation and interacting with cells and bioactive molecules to promote remodeling. Thus, the scaffold's intrinsic properties affect cellular processes involved in tissue regeneration, including migration, proliferation, differentiation, and protein synthesis. In this sense, due to its biological effect and clinical potential, Platelet Rich Plasma (PRP) fibrin could be considered a successful scaffold. Given the high variability in commercial PRPs formulations, this research focused on assessing the influence of cellular composition on fibrin membrane stability and remodeling cell activity. The stability and biological effect were evaluated at different time points via D-dimer, type I collagen and elastase quantification in culture media conditioned by Plasma Rich in Growth Factors - Fraction 1 (PRGF-F1), Plasma Rich in Growth Factors - Whole Plasma (PRGF-WP) and Leukocyte-rich Platelet Rich Plasma (L-PRP) membranes, and by gingival fibroblast cells seeded on them, respectively. Ultrastructure of PRP membranes was also evaluated. Histological analyses were performed after 5 and 18 days. Additionally, the effect of fibrin membranes on cell proliferation was determined. According to the results, L-PRP fibrin membranes degradation was complete at the end of the study, while PRGF membranes remained practically unchanged. Considering fibroblast behavior, PRGF membranes, in contrast to L-PRP ones, promoted extracellular matrix biosynthesis at the same time as fibrinolysis and enhanced cell proliferation. In conclusion, leukocytes in PRP fibrin membranes drastically reduce scaffold stability and induce behavioral changes in fibroblasts by reducing their proliferation rate and remodeling ability.

Sepia Melanin-Loaded Primary Human Gingival Keratinocytes: An In Vitro Model for Studies on Pigmented Gingiva

The objective of this study is the development of an in vitro cell culture model of pigmented gingival keratinocytes to provide a unique tool to assess oral care products such as toothpaste and evaluate whether pigmented gingival cells might be less susceptible than unpigmented cells to cytotoxicity by any toothpaste. Sepia melanin at various concentrations was added to primary human gingival keratinocyte (HGK) monolayers to identify the concentration at which melanin is sufficiently phagocytosed in the absence of cytotoxicity; this concentration was subsequently used to generate pigmented HGK model. Extracts from three commercial adult toothpastes (Crest 3D White, Sensodyne, and Colgate Optic) at different dilutions were evaluated in pigmented and unpigmented HGKs for cytotoxicity over a 24 h duration by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. Results demonstrated that HGKs showed a concentration-dependent uptake of sepia melanin with a significant linear correlation of pigment uptake. Moreover, the melanin was distributed perinuclearly in the cells, that was similar to the distribution of physiological gingiva in vivo. Further experiments were conducted with 25 µg/mL sepia melanin as higher concentrations induced cytotoxicity. Evaluation of three commercial toothpastes on unpigmented and pigmented HGKs showed no differential effects at any dilution. In summary, a model of pigmented HGKs with the ability to create a controlled level of pigmentation was demonstrated. Examination of extracts from three commercial toothpastes revealed similar cytotoxicity to both pigmented and unpigmented HGKs. In conclusion, this study shows that the artificially pigmented HGK model is an easy and low-cost tool that mimics the in vivo gingival pigmentation. Moreover, the evaluated toothpastes showed similar cytotoxicity to pigmented and unpigmented HGKs, suggesting that the presence of melanin did not impart any protective effects. Further studies to employ this pigmented HGK model to evaluate a large number of oral care products and include repeated exposures and longer duration are warranted.

Keratinocyte Proliferation and Hemidesmosome Formation on Surfaces for Dental Implants: In Vitro Study.

To demonstrate the likelihood of the polyetheretherketone (PEEK), zirconia (ZrO2), and titanium (Ti) disks to support proliferation and hemidesmosome formation of gingival cells. Water contact angle was performed on each material, and surface roughness (Ra) was measured. Scanning electron microscopy and x-ray photoelectron spectroscopy were used. Later, oral keratinocyte cells were cultured on disks, and metabolic activity and expression of hemidesmosome markers, integrin α6 and β4, in relation to the biomaterial disks at 1, 3, and 5 days of cell culture were quantified. Tissue culture polystyrene was used as the control. Statistical analysis was performed with analysis of variance (ANOVA) with Tukey post hoc comparison test. A P value of < .05 was considered statistically significant. The water contact angle ranged from 70.2 degrees (Ti) to a maximum of hydrophobicity of 93.3 degrees (PEEK). Ra was highest on ZrO2, followed by PEEK. Ti showed the most keratinocyte metabolic activity at 1, 3, and 5 culture periods. Contrarily, ZrO2 and PEEK disks had lower keratinocyte metabolic activity at all observation times, with no statistical differences between both groups. Integrin α6 and β4 expression was highest on TCPS and ZrO2 compared to Ti and PEEK. Keratinocytes proliferated faster on Ti than on ZrO2 and PEEK substrates, and expression of hemidesmosome formation markers, integrin α6 and β4, were higher on ZrO2 than either Ti or PEEK. Int J Oral Maxillofac Implants 2023;38:496-502. doi: 10.11607/jomi.9894.

Resolvin D1 (RvD1) Regulates Porphyromonas Gingivalis Lipopolysaccharide-induced Del-1 and Cytokine Expressions in Human Gingival Fibroblasts

Purpose: To detect the effect of Resolvin D1 (RvD1) on Developmental endothelial locus-1 (Del-1) and cytokine expressions of human gingival fibroblast cells exposed to Porphyromonas gingivalis lipopolysaccharide (P. gingivalis-LPS).&#x0D; &#x0D; Material and Methods: The effect of RvD1 on cell viability of human gingival fibroblasts exposed to P. gingivalis-LPS were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Meanwhile, the effect of RvE1 on Del-1 and cytokine (IL-1β, IL-6, IL-8, IL-10, IL-17) expressions of human gingival fibroblasts exposed to P. gingivalis-LPS were studied by real-time PCR experiment, statistical analysis was performed using GraphPad Prism version 5 for Windows.&#x0D; &#x0D; Results: Cell viability assay results demonstrated that RvD1 concentrations upregulated cell number compared to control group at 24 and at 72 hours. While RvD1 reduced IL-6, IL-8, IL-17 mRNA expression, IL-10 and Del-1 mRNA expression increased as a time- and dose-dependent manner. Also, IL-1β was not affected by RvD1 treatments. &#x0D; &#x0D; Conclusion: The increased expression of Del-1 and IL-10 by RvD1 down-regulated the pro-inflammatory cytokine expressions induced by P. gingivalis-LPS in gingival fibroblast. RvD1 displayed regulatory effects on gingival inflammation in P. gingivalis LPS-induced cell culture experiment. In particular, results of study display that Del-1 induced by RvD1 may have therapeutic potential to modulate periodontal inflammation.

Cytotoxicity and Mineralization Activity of Calcium Silicate-Based Root Canal Sealers Compared to Conventional Resin-Based Sealer in Human Gingival Fibroblast Cells.

Root canal obturation is performed by gutta-percha cones and sealer. Therefore, these materials, specially sealers, must be biocompatible. This study investigated the cytotoxicity and mineralization activity of two calcium silicate-based sealers (Endoseal MTA and Ceraseal) and an epoxy resin-based sealer (AH26). In this experiment, the cytotoxicity of Endoseal MTA, Ceraseal, and AH26 on human gingival fibroblast cells was examined using Methyl-Thiazol-Tetrazolium assay at time intervals of 24, 48, 72, and 120 hr. The mineralization activity of sealers was evaluated by Alizarin red staining assay. Prism, ver.3, software was used to perform statistical tests. One-way analysis of variance analysis, followed by Tukey's test, was used to determine the group differences. P-values < 0.05 were considered statistically significant. Cytotoxicity of sealers decreased gradually (P < 0.0001). AH26 showed the highest level of cytotoxicity (P < 0.001). In terms of cytotoxicity, no considerable differences were observed between the two-calcium silicate-based sealers (P > 0.05). AH26 showed the lowest mineralization activity (P < 0.0001). Among the calcium silicate-based sealers, mineralization and formation of calcium nodules were more frequently observed in the Endoseal MTA group (P < 0.001). The examined calcium silicate-based sealers had less cytotoxicity and higher mineralization activity than the resin-based sealer (AH26). There was negligible difference between the cytotoxicity of the two-calcium silicate-based, but the cell mineralization caused by Endoseal MTA was higher.

Effects of silver nanoparticle/graphene oxide composite on the properties of polymethyl methacrylate base material in vitro

ABSTRACT Polymethyl methacrylate (PMMA) has been widely used in stomatology to prepare denture bases. However, issues such as a porous structure and high water absorption rate facilitate bacterial growth. This study aimed to synthesize silver nanoparticle/graphene oxide (AgNPs/GO) composites by the chemical reduction method, which was mixed with PMMA by the ball milling method to improve the antibacterial properties of PMMA. Scanning electron microscopy and transmission electron microscopy showed that AgNPs were uniformly dispersed on the GO sheets. AgNPs/GO composite and GO were investigated using x-ray diffraction. The modified AgNPs/GO/PMMA composite demonstrated enhanced antibacterial properties against Streptococcus mutans based on the film adhesion test. Also, the number of bacteria decreased and the morphology of bacteria changed with the increase in mass fraction. Besides, the improved mechanical properties were confirmed by the friction and contact angle tests. Moreover, the composite did not induce cytotoxicity in human gingival mesenchymal stem cells.

Inhibition of LPS-Induced Inflammatory Response of Oral Mesenchymal Stem Cells in the Presence of Galectin-3

Galectin-3 (GAL-3) is a beta-galactoside binding lectin produced by mesenchymal stem cells (MSCs) and other cell sources under inflammatory conditions. Several studies have reported that GAL-3 exerts an anti-inflammatory action, regulated by its natural ligand GAL-3 BP. In the present study, we aimed to assess the GAL-3 mediated regulation of the MSC function in an LPS-induced inflammation setting. Human gingival mesenchymal stem cells (hGMSCs) were stimulated in vitro with LPSs; the expression of TLR4, NFκB p65, MyD88 and NALP3 were assessed in the hGMSCs via immunofluorescence imaging using confocal microscopy, Western blot assay, and RT-PCR before and after the addition of GAL-3, both alone and with the addition of its inhibitors. LPSs stimulated the expression of TLR4, NFκB p65, MyD88 and NALP3 in hGMSCs, which was inhibited by GAL-3. The addition of either GAL3-BP or the antibody to GAL-3 were able to revert the GAL-3-mediated effects, restoring the expression of TLR4, NFκB p65, MyD88 and NALP3. GAL-3 induces the downregulation of the LPS-induced inflammatory program in MSCs.

Chronic hyperglycemia reduces the expression of intercellular adhesion molecules and increases intercellular hyperpermeability in the periodontal epithelium.

Hyperglycemia in diabetes is closely associated with periodontal disease progression. This study aimed to investigate the effect of hyperglycemia on the barrier function of gingival epithelial cells as a cause of hyperglycemia-exacerbated periodontitis in diabetes mellitus. The abnormal expression of adhesion molecules in gingival epithelium in diabetes was compared between db/db and control mice. To study the effects of hyperglycemia on interepithelial cell permeability, the mRNA and protein expressions of adhesion molecules were investigated using a human gingival epithelial cell line (epi 4 cells) in the presence of either 5.5 mM glucose (NG) or 30 mM glucose (HG). Immunocytochemical and histological analyses were performed. We also studied HG-related intracellular signaling to assess abnormal adhesion molecule expression in the cultured epi 4 cells. The results of the proteomic analysis implied the abnormal regulation of cell-cell adhesion, and mRNA and protein expression assessments revealed the significant downregulation of Claudin1 expression in the gingival tissues of db/db mice (p < .05 vs control). Similarly, the mRNA and protein expressions of adhesion molecules were lower in epi 4 cells cultured under HG conditions than in those cultured under NG conditions (p < .05). Three-dimensional culture and transmission electron microscopy revealed reduced thickness of the epithelial cell layers with no flattened apical cells and heterogeneously arranged intercellular spaces among adjacent epi 4 cells under the HG. These results were consistent with the increased permeability of epi 4 cells under the HG relative to that of cells under the NG. This abnormal expression of intercellular adhesion molecules under the HG was related to the increased expression of receptors for advanced glycation end products (AGEs) and oxidative stress relative to that seen under the NG, along with stimulation of ERK1/2 phosphorylation in epi 4 cells. High glucose-induced impairment of intercellular adhesion molecule expression in gingival epithelial cells was related to the intercellular permeability of gingival cells, representing a possible link to hyperglycemia-related AGE signaling, oxidative stress, and ERK1/2 activation.

Fabrication of ECM Mimicking Bioactive Scaffold: A Regenerative Approach for MSC Mediated Applications.

Biomaterials are feasible resources that aids to replace damaged structures in our bodies. The most biologically active flora is Aloe vera which has many bioactive compounds that are anti-inflammatory, antimicrobial, and have ECM mimicking protein content which helps in the healing of wounds and also acts as an ECM factor for stem cell homing and differentiation. The Aloe vera containing 10 w/v of gelatin was lyophilized. Scaffolds had sharper morphology, greater hydrophilic properties, and a Young's modulus of 6.28 MPa and 15.9 MPa of higher tensile strength are desirable. In tissue engineering and regenerative medicine, biologically active scaffolds have been producing hopeful outcomes in both restoration and replacement, respectively. The objective of the present investigation is to test the idea that incorporating gelatin to Aloe vera scaffolds might enhance their structure, good biocompatibility, and possibly even bioactivity. The SEM picture of the composite scaffold revealed pore walls. The scaffolds had linked pores with diameters ranging from 93 to 296 μm. Aloe vera and the matrix interact well, according to the FTIR study, which could lead to a reduction in the amount of water-binding sites and a reduction in the material's ability to absorb water. Aloe vera with 10% gelatin (AV/G) scaffold was investigated for different biological reactions of human gingival tissue mesenchymal stem cells (MSCs) in terms of cell proliferation, morphology, and cell migration. The results demonstrated the potential of the AV/G scaffold as a biomaterial that offers new insight in the field of tissue engineering.

Activation of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 by Porphyromonas gingivalis regulates programmed cell death in epithelium

Background/purposeGingival epithelial cells form a physiological barrier against bacterial invasion. Programmed cell death (PCD) regulated by pathogen precognition receptors (PRRs) lead to tissue destruction and is closely related to inflammatory diseases. The purpose of this study was to investigate whether nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 (NLRP6) expresses in periodontal epithelium and induces PCD of epithelial cells infected by Porphyromonas gingivalis (P. gingivalis), therefore involves in periodontitis. Material and methodsThe expression of NLRP6 was detected in periodontal epithelium from human gingival sections and HaCaT cells stimulated by P. gingivalis. NLRP6 was over-expressed by adenovirus infection in HaCaT or knocked down by siRNA in P. gingivalis infected HaCaT, and the cell death was observed by transmission electron microscopy and flow cytometry analysis. In addition, qPCR and Western blot were performed to determine the expression of NLRP6 and the pyroptosis excutors, caspase-1 and gasdermin D. Enzyme-linked immunosorbent assay were performed to detect the secretion of IL-1β and IL-18. ResultsNLRP6 was up-regulated in both gingival epithelium of patients with periodontitis and P. gingivalis infected HaCaT. Over-expression of NLRP6 in HaCaT led to caspase-1 dependent pyroptosis. Interestingly, knockdown of NLRP6 with siRNA followed by P. gingivalis stimulation inhibited pyroptosis and induced apoptosis. ConclusionUp-regulation of NLRP6 by P. gingivalis in HaCaT led to pyroptosis, while knocking down NLRP6 inhibited pyroptosis and induced apoptosis, which indicated this PRR may play a crucial role in periodontitis by regulating PCD in periodontal epithelium.

Stem-cell based soft tissue substitutes: Engineering of crosslinked polylysine-hyaluronic acid microspheres ladened with gingival mesenchymal stem cells for collagen tissue regeneration and angiogenesis.

The aim of this study was to construct crosslinked polylysine-hyaluronic acid microspheres (pl-HAM) ladened with gingival mesenchymal stem cells (GMSCs) and explore its biologic behavior in soft tissue regeneration. The effects of the crosslinked pl-HAM on the biocompatibility and the recruitment of L-929 cells and GMSCs were detected in vitro. Moreover, the regeneration of subcutaneous collagen tissue, angiogenesis and the endogenous stem cells recruitment were investigated in vivo. We also detected the cell developing capability of pl-HAMs. The crosslinked pl-HAMs appeared to be completely spherical-shaped particles and had good biocompatibility. L-929 cells and GMSCs grew around the pl-HAMs and increased gradually. Cell migration experiments showed that pl-HAMs combined with GMSCs could promote the migration of vascular endothelial cells significantly. Meanwhile, the green fluorescent protein-GMSCs in the pl-HAM group still remain in the soft tissue regeneration area 2weeks after surgery. The results of in vivo studies showed that denser collagen deposition and more angiogenesis-related indicator CD31 expression in the pl-HAMs+ GMSCs + GeL group compared with the pl-HAMs + GeL group. Immunofluorescence showed that CD44, CD90, CD73 co-staining positive cells surrounded the microspheres in both pl-HAMs + GeL group and pl-HAM + GMSCs + GeL group. The crosslinked pl-HAM ladened with GMSCs system could provide a suitable microenvironment for collagen tissue regeneration, angiogenesis and endogenous stem cells recruitment, which may be an alternative to autogenous soft tissue grafts for minimally invasive treatments for periodontal soft tissue defects in the future.

Perturbation of mitochondrial dynamics links to the aggravation of periodontitis by diabetes

ABSTRACT Diabetes and periodontitis are prevalent diseases that considerably impact global economy and diabetes is a major risk factor of periodontitis. Mitochondrial dynamic alterations are involved in many diseases including diabetes and this study aims to evaluate their relevance with diabetes aggravated periodontitis. Sixty mice are randomly divided into 4 groups: control, periodontitis, diabetes and diabetic periodontitis. Periodontitis severity is evaluated by alveolar bone loss, inflammation and oxidative stress status. Mitochondrial structural and functional defects are evaluated by the mitochondrial fission/fusion events, mitochondrial reactive oxygen species (ROS) accumulation, complex activities and adenosine triphosphate (ATP) production. Advanced glycation end product (AGE) and Porphyromonas gingivalis are closely related to periodontitis occurrence and development. Human gingival fibroblast cells (HGF-1) are used to investigate the AGE role and lipopolysaccharide (LPS) from Porphyromonas gingivalis (P-LPS) in aggravating diabetic periodontitis by mitochondrial dynamic and function alterations. In vivo, diabetic mice with periodontitis show severe bone loss, increased inflammation and oxidative stress accumulation. Among mice with periodontitis, diabetic mice show worse mitochondrial dynamic perturbations than lean mice, along with fusion protein levels inducing more mitochondrial fission in gingival tissue. In vitro, AGEs and P-LPS co-treatment causes severe.

Incorporation of Magnesium and Zinc Metallic Particles in PLGA Bi-layered Membranes with Sequential Ion Release for Guided Bone Regeneration.

Guided bone regeneration (GBR) membranes are commonly used for periodontal tissue regeneration. Due to the complications of existing GBR membranes, the design of bioactive membranes is still relevant. GBR membranes with an asymmetric structure can accommodate the functional requirements of different interfacial tissues. Here, poly(lactic acid-glycolic acid) (PLGA) was selected as the matrix for preparing a bi-layered membrane with both dense and porous structure. The dense layer for blocking soft tissues was incorporated with zinc (Zn) particles, while the porous layer for promoting bone regeneration was co-incorporated with magnesium (Mg) and Zn particles. Mg/Zn-embedded PLGA membranes exhibited 166% higher mechanical strength in comparison with pure PLGA membranes and showed suitable degradation properties with a sequential ion release behavior of Mg2+ first and continuously Zn2+. More importantly, the release of Zn2+ from bi-layered PLGA endowed GBR membranes with excellent antibacterial activity (antibacterial rate > 69.3%) as well as good cytocompatibility with MC3T3-E1 (mouse calvaria pre-osteoblastic cells) and HGF-1 (human gingival fibroblast cells). Thus, the asymmetric bi-layered PLGA membranes embedded with Mg and Zn particles provide a simple and effective strategy to not only reinforce the PLGA membrane but also endow membranes with osteogenic and antibacterial activity due to the continuous ion release profile, which serves as a promising candidate for use in GBR therapy.

Effect of Low-level Laser Therapy on the Viability and Proliferation of Gingival Mesenchymal Stem Cells: An Ex Vivo Pilot Study

Effect of Low-level Laser Therapy on the Viability and Proliferation of Gingival Mesenchymal Stem Cells: An Ex Vivo Pilot Study

Synergistic Effect of Anethole and Platinum Drug Cisplatin against Oral Cancer Cell Growth and Migration by Inhibiting MAPKase, Beta-Catenin, and NF-κB Pathways.

Cisplatin is a common drug used to treat patients with oral squamous cell carcinoma. However, cisplatin-induced chemoresistance poses a major challenge to its clinical application. Our recent study has shown that anethole possesses an anti-oral cancer effect. In this study, we examined the combined effect of anethole and cisplatin on oral cancer therapy. Gingival cancer cells Ca9-22 were cultured in the presence of various concentrations of cisplatin with or without anethole. The cell viability/proliferation and cytotoxicity were evaluated, respectively, by MTT, Hoechst staining, and LDH assay, while colony formation was measured by crystal violet. Oral cancer cell migration was evaluated by the scratch method. Apoptosis, caspase activity, oxidative stress, MitoSOX, and mitochondrial membrane potential (ΔΨm) levels were evaluated by flow cytometry, and the inhibition of signaling pathways was investigated by Western blot. Our results show that anethole (3 µM) potentiates cisplatin-induced inhibition of cell proliferation and decreases the ΔΨm on Ca9-22 cells. Furthermore, drug combination was found to inhibit cell migration and enhanced cisplatin cytotoxicity. The combination of anethole and cisplatin potentiates cisplatin-induced oral cancer cell apoptosis through the activation of caspase, while we also found anethole and cisplatin to enhance the cisplatin-induced generation of reactive oxygen species (ROS) and mitochondrial stress. In addition, major cancer signaling pathways were inhibited by the combination of anethole and cisplatin such as MAPKase, beta-catenin, and NF-κB pathways. This study reports that the combination of anethole and cisplatin might provide a beneficial effect in enhancing the cisplatin cancer cell-killing effect, thus lowering the associated side effects.

Advanced co-culture model: Soft tissue cell and bacteria interactions at the transgingival dental implant interface.

To better simulate and understand the clinical situation in which tissue cells and bacteria compete for settlement on an implant surface, the aim was to develop an improved transgingival co-culture model. For this model human gingival fibroblasts (HGF) were seeded on different titanium surfaces in the presence of the early colonizer Streptococcus gordonii or mixed oral bacteria. Subsequently adhesion and viability of HGF cells was analyzed. Simultaneous co-culture showed no decrease in the viability of HGF cells at early stages compared to the control group. However, a moderate impact on HGF viability (76±23%) was observed after 4h of co-culture, which then significantly decreased after 5h (21±2%) of co-cultivation, resulting in cell death and detachment from the surface. Further experiments including saliva pre-treatment of smooth and structured titanium surfaces with Streptococcus gordonii or mixed oral bacteria suggested a cell-protective property of saliva. Our study revealed that during simultaneous co-culture of cells and bacteria, which resembles the clinical situation the closest, the viability of gingival cells is considerably high in the early phase, suggesting that increasing initial cell adhesion rather than antibacterial functionality is a major goal and a relevant aspect in the development and testing of transgingival implant and abutment surface modifications.

S-1-propenyl-L-cysteine suppresses lipopolysaccharide-induced expression of matrix metalloproteinase-1 through inhibition of tumor necrosis factor-α converting enzyme-epidermal growth factor receptor axis in human gingival fibroblasts.

Periodontal disease is the most common dental health problem characterized by the destruction of connective tissue and the resorption of alveolar bone resulting from a chronic infection associated with pathogenic bacteria in the gingiva. Aged garlic extract has been reported to improve gingival bleeding index and probing pocket depth score in patients with mild to moderate periodontitis. Although our previous study found that aged garlic extract and its constituents suppressed the tumor necrosis factor-α-induced inflammatory responses in a human gingival epithelial cell line, the mechanism underlying the effect of aged garlic extract on the destruction of the gingiva remains unclear. The present study investigated the effect of S-1-propenyl-L-cysteine, one of the major sulfur bioactive compounds in aged garlic extract, on the lipopolysaccharide-induced expression of matrix metalloproteinases in human gingival fibroblasts HGF-1 cells. Matrix metalloproteinases are well known to be closely related to the destruction of the gingiva. We found that S-1-propenyl-L-cysteine suppressed the lipopolysaccharide-induced expression and secretion of matrix metalloproteinase-1 in HGF-1 cells. In addition, S-1-propenyl-L-cysteine inhibited the lipopolysaccharide-induced phosphorylation of epidermal growth factor receptor and expression of the active form of tumor necrosis factor-α converting enzyme. Furthermore, the inhibitors of epidermal growth factor receptor tyrosine kinase and tumor necrosis factor-α converting enzyme, AG-1478 and TAPI-1, respectively, reduced the lipopolysaccharide-induced protein level of matrix metalloproteinase-1, as did S-1-propenyl-L-cysteine. Taken together, these results suggested that S-1-propenyl-L-cysteine suppresses the lipopolysaccharide-induced expression of matrix metalloproteinase-1 through the blockade of the tumor necrosis factor-α converting enzyme-epidermal growth factor receptor axis in gingival fibroblasts.

Novel ITGB6 variants cause hypoplastic-hypomineralized amelogenesis imperfecta and taurodontism: characterization of tooth phenotype and review of literature

ObjectivesTo characterize phenotype and genotype of amelogenesis imperfecta (AI) in a Thai patient, and review of literature.Materials and methodsVariants were identified using trio-exome and Sanger sequencing. The ITGB6 protein level in patient’s gingival cells was measured. The patient’s deciduous first molar was investigated for surface roughness, mineral density, microhardness, mineral composition, and ultrastructure.ResultsThe patient exhibited hypoplastic-hypomineralized AI, taurodontism, and periodontal inflammation. Exome sequencing identified the novel compound heterozygous ITGB6 mutation, a nonsense c.625 G > T, p.(Gly209*) inherited from mother and a splicing c.1661-3 C > G from father, indicating AI type IH. The ITGB6 level in patient cells was significantly reduced, compared with controls. Analyses of a patient’s tooth showed a significant increase in roughness while mineral density of enamel and microhardness of enamel and dentin were significantly reduced. In dentin, carbon was significantly decreased while calcium, phosphorus, and oxygen levels were significantly increased. Severely collapsed enamel rods and a gap in dentinoenamel junction were observed. Of six affected families and eight ITGB6 variants that have been reported, our patient was the only one with taurodontism.ConclusionWe report the hypoplasia/hypomineralization/taurodontism AI patient with disturbed tooth characteristics associated with the novel ITGB6 variants and reduced ITGB6 expression, expanding genotype, phenotype, and understanding of autosomal recessive AI.

In Vitro Preventive Effect and Mechanism of Action of Weissella cibaria CMU against Streptococcus mutans Biofilm Formation and Periodontal Pathogens.

In this study, we evaluated the in vitro anti-biofilm, antibacterial, and anti-inflammatory activity of Weissella cibaria CMU (CMU), an oral probiotic, against periodontopathogens. Compared to other oral probiotics, CMU showed a superior inhibitory effect on the biofilm formation and growth of Streptococcus mutans on orthodontic wires and artificial teeth (p < 0.05). CMU exerted potent antibacterial effects against S. mutans and Porphyromonas gingivalis according to a line test. In human gingival fibroblasts (HGFs) stimulated by P. gingivalis, Fusobacterium nucleatum, or Prevotella intermedia, CMU suppressed the gene expression of pro-inflammatory cytokines [interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor-α] in a dose-dependent manner (p < 0.05). CMU restored the production of the tissue inhibitor of metalloproteinase-1 following its inhibition by P. gingivalis, and it suppressed the expression of matrix metalloproteinase (MMP)-1 and -3 induced by periodontopathogens (p < 0.05). Moreover, CMU needed direct contact with HGFs to exert their anti-inflammatory function, indicating that they act directly on gingival cells to modulate local inflammation. Our preclinical study provides evidence for the potential benefits of topical CMU treatments in preventing the development of caries and periodontitis caused by the dysbiosis of the dental plaque microbiome.