Oral infection with Porphyromonas gingivalis augmented gingival epithelial barrier molecules alteration with aging

OBJECTIVE

Disruption of the gingival epithelial barrier is often mediated by aging or the pathogen Porphyromonas gingivalis. This study examined the combined effects of aging and P. gingivalis exposure on gingival epithelial barrier molecules.

METHODS

In vitro experiments involved treating young- and senescence-induced primary human gingival epithelial progenitor cells (HGEPp) with P. gingivalis lipopolysaccharide (LPS). Transepithelial electrical resistance (TER) and paracellular permeability were measured. In vivo, male C57BL/6J mice aged 10 (young) and 80 (old) weeks were divided into four groups: young, old, young with P. gingivalis (Pg-Young) inoculation, and old with P. gingivalis (Pg-Old) inoculation. P. gingivalis was inoculated orally thrice a week for 5 weeks. The mice were sacrificed 30 days after the last inoculation, and samples were collected for further procedures. The junctional molecules (Claudin-1, Claudin-2, E-cadherin, and Connexin) were analyzed for mRNA expression using qRT-PCR and protein production using western blotting and immunohistochemistry. The alveolar bone loss and inflammatory cytokine levels in gingival tissues were also assessed.

RESULTS

LPS-treated senescent cells exhibited a pronounced reduction in TER, increased permeability to albumin protein, significant upregulation of Claudin-1 and Claudin-2, and significant downregulation of E-cadherin and Connexin. Furthermore, the Pg-Old group showed identical results with aging in addition to an increase in alveolar bone loss, significantly higher than that in the other groups.

CONCLUSION

In conclusion, the host susceptibility to periodontal pathogens increases with age through changes in the gingival epithelial barrier molecules.

Ingenuity pathway analysis of gingival epithelial cells stimulated with estradiol and progesterone

OBJECTIVE

Periodontal disease is a risk factor for preterm delivery, and elevated female hormone levels during pregnancy promote hormone-dependent periodontopathogenic bacterial growth and gingivitis. Although the saliva of pregnant women contains female hormones at elevated levels, their effects on the gingiva are poorly understood. Therefore, in this study, we investigated the effects of estradiol and progesterone stimulation on gingival epithelial cells via ingenuity pathway analysis.

METHODS

Human gingival epithelial progenitors were cultured in a CnT-Prime medium; 17β-estradiol (E2) and progesterone (P4) were used as the reagents. Cells treated with dimethyl sulfoxide alone were used as the control group. Cells in the control and experimental groups were incubated for 12 h. RNA was extracted from the cultured cells, RNA-Seq was performed, and pathway analysis was conducted.

RESULTS

Differentially expressed genes were detected for 699 (over 2-fold increase) and 348 (decrease) genes in group E2 and for 1448 (increase) and 924 (decrease) genes in group P4 compared with those in the control group (FDR <0.05, n = 4). The z-scores of the pathways suggest that E2 and P4 increased the activity of the wound healing signaling pathway. The activation of this pathway was higher in the E2 and P4 groups than that in the control group.

CONCLUSIONS

The results of this study suggest that estradiol and progesterone may affect gingival homeostasis and wound healing.

Transcriptomic analysis of the submandibular gland under psychological stress condition

BACKGROUND

Psychological stress is associated with changes in salivary flow and composition. However, studies to show the effect of psychological stress on the transcriptome of the salivary gland are limited. This study aims to perform a transcriptomic analysis of the submandibular gland under psychological stress using a chronic restraint stress model of rats.

METHODS

Sprague-Dawley rats were divided into stress groups and control groups. Psychological stress was induced in the stress group rats by enclosing them in a plastic tube for 4 h daily over 6 weeks. RNA sequencing was performed on RNA extracted from the submandibular gland. The differentially expressed genes were identified, and the genes of interest were further validated using qRT-PCR, immunofluorescence, and western blot.

RESULTS

A comparison between control and stress groups showed 45 differentially expressed genes. The top five altered genes in RNA sequencing data showed similar gene expression in qRT-PCR validation. The most downregulated gene in the stress group, FosB, was a gene of interest and was further validated for its protein-level expression using immunofluorescence and western blot. The genesets for gene ontology cellular component, molecular function, and KEGG showed that pathways related to ribosome biosynthesis and function were downregulated in the stress group compared to the control.

CONCLUSION

Psychological stress showed transcriptomic alteration in the submandibular gland. The findings may be important in understanding stress-related oral diseases.

Acanthopanax senticosus ameliorates steatohepatitis through HNF4 alpha pathway activation in mice

Non-alcoholic fatty liver disease is a common liver disease worldwide, and is associated with dysregulation of lipid metabolism, leading to inflammation and fibrosis. Acanthopanax senticosus Harms (ASH) is widely used in traditional medicine as an adaptogen food. We examined the effect of ASH on steatohepatitis using a high-fat diet mouse model. Mice were fed a choline-deficient, L-amino acid-defined, high-fat diet with ASH extract (ASHE). After 6 weeks, liver RNA transcriptome sequencing (RNA-Seq) was performed, followed by Ingenuity Pathway Analysis (IPA). Our findings revealed that mice fed a high-fat diet with 5% ASHE exhibited significantly reduced liver steatosis. These mice also demonstrated alleviated inflammation and reduced fibrosis in the liver. IPA of RNA-Seq indicated that hepatocyte nuclear factor 4 alpha (HNF4 alpha), a transcription factor, was the activated upstream regulator (P-value 0.00155, z score = 2.413) in the liver of ASHE-fed mice. Adenosine triphosphate binding cassette transporter 8 and carboxylesterase 2, downstream targets of HNF4 alpha pathway, were upregulated. Finally, ASHE-treated HepG2 cells exposed to palmitate exhibited significantly decreased lipid droplet contents. Our study provides that ASHE can activate HNF4 alpha pathway and promote fat secretion from hepatocytes, thereby serving as a prophylactic treatment for steatohepatitis in mice.

The Role of Hedgehog Signaling in the Melanoma Tumor Bone Microenvironment

A crucial regulator in melanoma progression and treatment resistance is tumor microenvironments, and Hedgehog (Hh) signals activated in a tumor bone microenvironment are a potential new therapeutic target. The mechanism of bone destruction by melanomas involving Hh/Gli signaling in such a tumor microenvironment is unknown. Here, we analyzed surgically resected oral malignant melanoma specimens and observed that Sonic Hedgehog, Gli1, and Gli2 were highly expressed in tumor cells, vasculatures, and osteoclasts. We established a tumor bone destruction mouse model by inoculating B16 cells into the bone marrow space of the right tibial metaphysis of 5-week-old female C57BL mice. An intraperitoneal administration of GANT61 (40 mg/kg), a small-molecule inhibitor of Gli1 and Gli2, resulted in significant inhibition of cortical bone destruction, TRAP-positive osteoclasts within the cortical bone, and endomucin-positive tumor vessels. The gene set enrichment analysis suggested that genes involved in apoptosis, angiogenesis, and the PD-L1 expression pathway in cancer were significantly altered by the GANT61 treatment. A flow cytometry analysis revealed that PD-L1 expression was significantly decreased in cells in which late apoptosis was induced by the GANT61 treatment. These results suggest that molecular targeting of Gli1 and Gli2 may release immunosuppression of the tumor bone microenvironment through normalization of abnormal angiogenesis and bone remodeling in advanced melanoma with jaw bone invasion.

Effects of prolonged stimulation with heated tobacco products (Ploom TECH+ ) on gingival epithelial cells

OBJECTIVE AND BACKGROUND

Heated tobacco products have recently become commercially available. These products, as well as combustible cigarettes, produce aerosols; the risk of various diseases associated with heated tobacco products may be the same or higher than that with combustible cigarettes. In this study, we examined the effect of Ploom TECH⁺ extract on gingival epithelial cells.

METHODS

Tobacco leaves from Ploom TECH⁺ tobacco capsules and water were mixed and heated; the supernatant subsequently collected was the heated tobacco product (HTP; control: HTP not added). Normal human gingival epithelial progenitors were cultured alternately with or without HTP for a total of 1 month. Subsequently, RNA, DNA, and proteins were isolated from these samples and comprehensively analyzed using RNA sequencing (RNA-seq), reduced representation bisulfite sequencing (RRBS), and western blotting, respectively.

RESULTS

RNA-seq revealed that 284 genes showed a twofold increase and 145 genes showed a twofold decrease in gene expression. A heat map showed genetic differences between the control and HTP groups. A principal component analysis plot showed a clear genetic distribution between the control and HTP. Gene Ontology (GO) analysis showed that genes related to seven GO terms, including cornification and keratinization, were induced by long-term HTP stimulation. By contrast, GO pathways with a significant decrease in component expression were not detected. RRBS revealed that CpG island methylation increased more than twofold in 158 genes and decreased to less than twofold in 171 genes. Methylation of these CpG islands was not correlated with changes in gene expression levels. HTP treatment increased S100A7 expression.

CONCLUSION

Long-term HTP stimulation affected epithelial differentiation and keratinization of gingival epithelial cells. Thus, habitual use of Ploom TECH⁺ may be a risk factor for tobacco-related oral mucosal diseases.

Regaining enamel color quality using enamel matrix derivative

This study aimed to demonstrate and compare the accuracy of tooth shade selection due to the remineralized enamel crystal with enamel matrix derivative (EMD) in vitro. Etched enamel slices were immersed in four types of mineralization buffers for 16 h. Sodium fluoride (NaF) was added to final concentrations of 1-100 ppm with the mineralization buffer that demonstrated the highest mineralization efficiency. EMD was added to the mineralization buffer containing NaF to see if it has any remineralization capacities. The remineralized enamel crystal was analyzed by SEM and XRD. The tooth shade was evaluated by CIE L*a*b*. The results showed that, without NaF, plate-like nanocrystals were formed on the enamel surface, but with NaF, needle-like nanocrystals were formed. By adding EMD, a layer of well-compacted hydroxyapatite crystals was successfully precipitated onto the natural enamel surface. No significant differences were observed in the L* value of the mineralization surface pre-etching and after mineralization buffer containing NaF and EMD. A new method has been developed to recover the color quality of enamel, as well as to mineralize the tooth enamel by constructing hydroxyapatite crystals with mineralization buffers containing NaF and EMD on the etched tooth surface.

The effect of Porphyromonas gingivalis on the gut microbiome of mice in relation to aging

BACKGROUND AND OBJECTIVE

The translocation of oral bacteria, including Porphyromonas gingivalis, to the gut has been shown to alter gut microbiome. However, the effect of P. gingivalis on gut microbiome in relation to aging has not been demonstrated. We hypothesize that P. gingivalis has more detrimental effect on gut environment with increased age. The objective of this study is to investigate the effect of P. gingivalis on gut environment using aged mice.

MATERIALS AND METHODS

C57BL/6J mice aged 4 weeks (young) or 76 weeks (old) were divided into four groups: control-young, control-old, P. gingivalis-administered young, and P. gingivalis-administered old. P. gingivalis was orally administered thrice weekly for 5 weeks. At 30 days after the last P. gingivalis administration, 16S rRNA sequencing was performed to study the gut microbiome. The mRNA and protein expression of intestinal junctional barrier molecules and the levels of the inflammatory cytokines IL-1β and TNF-α in the serum were evaluated.

RESULTS

Significant differences in the gut microbiomes between the groups, in terms of taxonomic abundance, bacterial diversity, and predicted metagenome function, were observed. A significant reduction in the alpha diversity and in the abundance of beneficial bacteria, such as Akkermansia and Clostridiaceae, in the P. gingivalis-administered old mice was observed. The mRNA and protein levels of Claudin-1 and Claudin-2 in the intestine were significantly elevated, while E-cadherin was significantly downregulated in the P. gingivalis-administered old mice, as were the serum levels of IL-1β and TNF-α.

CONCLUSION

The effect of P. gingivalis on the gut environment is more pronounced in old mice than in young mice.

Gut flora alterations due to lipopolysaccharide derived from Porphyromonas gingivalis

Gut dysbiosis induces 'leaky gut,' a condition associated with diabetes, NASH, and various auto-immune diseases. Porphyromonas gingivalis is a periodontopathic bacterium which causes periodontal tissue breakdown, and often enters the systemic blood flow. Oral administration of P. gingivalis induced gut dysbiosis in mice model, but no systemic administration of P. gingivalis has been reported thus far. In the present study, we investigated the effect of P. gingivalis-derived lipopolysaccharide (Pg-LPS) on the intestinal flora of our established mouse model. Eight-week-old C57BL/6J mice were intraperitoneally administered Pg-LPS. Three months later, DNA was extracted from stool, and RNA from the small and large intestines. After euthanizing the mice, pathological sections of the intestinal tract were prepared and stained with hematoxylin and eosin (H&E). Tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 expression levels were evaluated using quantitative PCR. 16S rRNA gene PCR amplicon analysis data were acquired using NGS. Microbial diversity and composition were analyzed using Quantitative Insights into Microbial Ecology 2. Furthermore, alterations in microbial function were performed by PICRUSt2. No significant inflammatory changes were observed in the H&E. No significant differences in the mRNA levels of IL-1β, IL-6, and TNF-α were observed between the groups. Pg-LPS administration decreased the abundance of Allobacterium in the gut. A predictive metagenomic analysis by PICRUSt2 and STAMP showed that 47 pathways increased and 17 pathways decreased after Pg-LPS administration. Systemic application of periodontal pathogens may cause changes in the intestinal flora which may affect the physiological functions of the intestinal tract.

Alterations in the oral microbiome of individuals with a healthy oral environment following COVID-19 vaccination

BACKGROUND

Several reports suggest that the microbiome of the digestive system affects vaccine efficacy and that the severity of coronavirus disease (COVID-19) is associated with decreased diversity of the oral and/or intestinal microbiome. The present study examined the effects of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine on the oral microbiome.

METHODS

Forty healthy Japanese oral healthcare personnel were recruited, and unstimulated saliva was collected before vaccination, after the 1st vaccination, and after the 2nd vaccination. Genomic DNA was extracted from saliva samples, and PCR amplicons of the 16S rRNA gene were analyzed using next-generation sequencing. Microbial diversity and composition were analyzed using Quantitative Insights into Microbial Ecology 2. In addition, alterations in microbial function were assessed using PICRUSt2.

RESULTS

SARS-CoV-2 mRNA vaccination significantly increased oral bacterial diversity and significantly decreased the proportion of the genus Bacteroides.

CONCLUSIONS

The SARS-CoV-2 mRNA vaccine alters the oral microbiome; accordingly, vaccination might have beneficial effects on oral health.

Analysis of the cells isolated from epithelial cell rests of Malassez through single-cell limiting dilution

The epithelial cell rests of Malassez (ERM) are essential in preventing ankylosis between the alveolar bone and the tooth (dentoalveolar ankylosis). Despite extensive research, the mechanism by which ERM cells suppress ankylosis remains uncertain; perhaps its varied population is to reason. Therefore, in this study, eighteen unique clones of ERM (CRUDE) were isolated using the single-cell limiting dilution and designated as ERM 1-18. qRT-PCR, ELISA, and western blot analyses revealed that ERM-2 and -3 had the highest and lowest amelogenin expression, respectively. Mineralization of human periodontal ligament fibroblasts (HPDLF) was reduced in vitro co-culture with CRUDE ERM, ERM-2, and -3 cells, but recovered when an anti-amelogenin antibody was introduced. Transplanted rat molars grown in ERM-2 cell supernatants produced substantially less bone than those cultured in other cell supernatants; inhibition was rescued when an anti-amelogenin antibody was added to the supernatants. Anti-Osterix antibody staining was used to confirm the development of new bones. In addition, next-generation sequencing (NGS) data were analysed to discover genes related to the distinct roles of CRUDE ERM, ERM-2, and ERM-3. According to this study, amelogenin produced by ERM cells helps to prevent dentoalveolar ankylosis and maintain periodontal ligament (PDL) space, depending on their clonal diversity.

Clinical Characteristics of Predominantly Unilateral Oral Cenesthopathy With and Without Neurovascular Contact

Oral cenesthopathy (OC) is characterized by unusual oral discomfort without corresponding evidence, and it has often been categorized as "delusional disorder, somatic type". Regarding possible causative factors of OC, involvement of neurovascular contact (NVC) of the trigeminal nerve, which transmits not only pain but also thermal, tactile, and pressure sensations, has never been observed yet. This study aimed to investigate the relationship between clinical characteristics of unilateral OC and the presence of trigeminal nerve NVC. This is a retrospective comparative study that involved 48 patients having predominantly unilateral OC who visited the Psychosomatic Dentistry Clinic of Tokyo Medical and Dental University between April 2016 and February 2019. Magnetic resonance imaging was performed to assess NVC presence. The Oral Dysesthesia Rating Scale (Oral DRS) was used to assess the various oral sensations and functional impairments besides psychometric questionnaires. Clinical characteristics were retrospectively obtained from the patients' medical charts. NVC was present in 45.8% (22/48) of the patients. There was no significant difference in sex, age, psychiatric history, oral psychosomatic comorbidity, and psychometric questionnaire scores between patients with and without NVC. However, compared to the patients with NVC, the patients without NVC had significantly higher scores for overall subjective severity of OC symptoms (p = 0.008). Moreover, patients having predominantly unilateral OC without NVC showed significantly higher scores in symptom severity and functional impairment of the following parameters: movement (p = 0.030), work (p = 0.004), and social activities (p = 0.010). In addition, compared with the patients with NVC, the patients without NVC showed significantly higher averages of the total symptom severity scale (SSS) and functional impairment scale (FIS) scores in the Oral DRS (p = 0.015 and p = 0.031, respectively). Furthermore, compared with the patients with NVC, the patients without NVC had significantly higher numbers of corresponding symptoms in both the SSS and FIS (p = 0.041 and p = 0.007, respectively). While NVC may be involved in the indescribable subtle OC symptoms, more complex mechanisms may also exist in OC patients without NVC, which yield varying and more unbearable oral symptoms.

Increased integrity of cell-cell junctions accompanied by increased expression of claudin 4 in keratinocytes stimulated with vitamin D3

The stratified squamous epithelium has a multilayer structure formed by the differentiation of the keratinized epithelium, which covers the skin and oral mucosa. The epithelium plays a central role in regulating the interactions between the immune system and pathogens. The tight junction (TJ) barrier, which is composed of adhesion molecules called claudins (CLDN), is critical for the homeostasis of the skin and oral mucosa. Furthermore, the crucial roles of vitamin D3 (VD3) in the pathogeneses of skin and oral mucosal disease have been suggested. The aim of this in vitro study was to observe the correlations between the integrity of the keratinocyte population and the expression levels of CLDN1 and CLDN4 in gingival epithelial cells, stimulated with VD3. CLDN 1 and 4 expression levels were down and upregulated, respectively, in the cells stimulated with VD3. Additionally, transepithelial electrical resistance (TEER) levels were increased in the stimulated cells when compared to the controls. These findings indicate that CLDN 4 may play a more important role in the TJ barrier than CLDN 1. Hence, the therapeutic effect of VD3 in skin and oral diseases may be regulated by the increase in the expression of CLDN 4.

Intraosseous clear cell mucoepidermoid carcinoma in the maxilla: A case report and review of literature

We reported an extremely rare case regarding intraosseous clear cell variant of mucoepidermoid carcinoma in maxilla.

An in vitro senescence model of gingival epithelial cell induced by hydrogen peroxide treatment

Gingival tissue shows progressive changes with aging and an in vitro model of gingival tissue could be useful in understanding age-associated oral diseases. The present study aims to establish a hydrogen peroxide (H₂O₂) treatment model to induce aging in human gingival epithelial cells. In addition, fisetin, a flavonoid component studied for the anti-aging property is used to examine if it could reverse the induced senescence. Primary human gingival epithelial progenitor (HGEPp) cells were cultured and treated with different concentrations of H₂O₂. A cell vitality and morphology, senescence-associated beta-galactosidase (SA-β-gal) staining, mRNA and protein expression analysis of known senescence markers p16, p21, and p53, and cell cycle assay were performed. The cells showed dose-dependent changes in vitality and morphology, SA-β-gal staining, relative mRNA and protein expression, and cell cycle assay after H₂O₂ treatment. Based on these results, 400 μM H₂O₂ was considered as an optimal concentration to induce senescence. Treatment of senescence-induced cells with fisetin downregulated all the senescence markers used in this study. In conclusion, a senescence model of gingival epithelial cells induced by hydrogen peroxide treatment was established which could be employed to study age-related periodontal diseases.

A challenging diagnosis of a mucocele in the maxillary gingiva: Case report and literature review

INTRODUCTION

Mucoceles are mucous extravasation phenomena resulting from spontaneous ductal rupture or, less commonly, a traumatic cutting of a salivary excretory duct. Occasionally, the appearance of a mucocele closely resembles a neoplastic lesion, and it can be difficult to diagnose.

PRESENTATION OF CASE

A 74-year-old Japanese male patient was referred to our clinic with painless swelling related to the upper right canine-premolar area. Preoperative imaging of the lesion revealed that it was fluid-filled and the histopathological biopsy suggested a myxoid tumor. We excised the lesion with the patient under general anesthesia, using safety margins based on the histology of the biopsy specimen to reach the definitive diagnosis and treatment. The final pathological diagnosis was a mucocele in the vicinity with an aberrant small salivary gland. Follow-up visits showed complete healing of the epithelium, and no recurrence has been observed during the subsequent 30 months.

DISCUSSION

In cases with a difficult definitive diagnosis based on medical history, diagnostic imaging and pathological examination, it is important to proceed carefully with the possibility of a tumor in mind.

CONCLUSION

This case emphasizes that some mucous cysts are challenging for clinicians in terms of diagnosis and treatment due to an uncommon presentation.

ITGA2, LAMB3, and LAMC2 may be the potential therapeutic targets in pancreatic ductal adenocarcinoma: an integrated bioinformatics analysis

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer with an abysmal prognosis rate over the last few decades. Early diagnosis and prevention could effectively combat this malignancy. Therefore, it is crucial to discover potential biomarkers to identify asymptomatic premalignant or early malignant tumors of PDAC. Gene expression analysis is a powerful technique to identify candidate biomarkers involved in disease progression. In the present study, five independent gene expression datasets, including 321 PDAC tissues and 208 adjacent non-cancerous tissue samples, were subjected to statistical and bioinformatics analysis. A total of 20 differentially expressed genes (DEGs) were identified in PDAC tissues compared to non-cancerous tissue samples. Gene ontology and pathway enrichment analysis showed that DEGs were mainly enriched in extracellular matrix (ECM), cell adhesion, ECM-receptor interaction, and focal adhesion signaling. The protein-protein interaction network was constructed, and the hub genes were evaluated. Collagen type XII alpha 1 chain (COL12A1), fibronectin 1 (FN1), integrin subunit alpha 2 (ITGA2), laminin subunit beta 3 (LAMB3), laminin subunit gamma 2 (LAMC2), thrombospondin 2 (THBS2), and versican (VCAN) were identified as hub genes. The correlation analysis revealed that identified hub genes were significantly interconnected. Wherein COL12A1, FN1, ITGA2, LAMB3, LAMC2, and THBS2 were significantly associated with PDAC pathological stages. The Kaplan-Meier survival plots revealed that ITGA2, LAMB3, and LAMC2 expression were inversely correlated with a prolonged patient survival period. Furthermore, the Human Protein Atlas database was used to validate the expression and cellular origins of hub genes encoded proteins. The protein expression of hub genes was higher in pancreatic cancer tissue than in normal pancreatic tissue samples, wherein ITGA2, LAMB3, and LAMC2 were exclusively expressed in pancreatic cancer cells. Pancreatic cancer cell-specific expression of these three proteins may play pleiotropic roles in cancer progression. Our results collectively suggest that ITGA2, LAMB3, and LAMC2 could provide deep insights into pancreatic carcinogenesis molecular mechanisms and provide attractive therapeutic targets.

Medial clavicle fracture with bone destruction after radical neck dissection combined with postoperative chemotherapy for secondary cervical lymph node metastasis of tongue cancer: a case report

BACKGROUND

Clavicle fractures (CF) after radical neck dissection (RND) for oral cancer are rare but are thought to occur as a result of myotonia and decreased blood supply to the muscles around the clavicle after RND. The current report presents a rare case of a non-neoplastic pathological CF after RND, and discusses the role of imaging examinations for the timely detection of CF.

CASE REPORT

An 82-year-old Japanese man underwent RND followed by chemotherapy without radiotherapy for secondary metastasis of the right cervical lymph node after resection of tongue cancer. Computed tomography at 6 months after RND revealed a fracture with bone destruction in the proximal end of the right clavicle. He had no history of trauma at the site of the fracture and no symptoms. The possibility of bone metastasis of the clavicle was considered; however, the bone destruction had not advanced 6 years after the discovery of the fracture. The CF was thus finally considered to be a side effect of RND, rather than metastasis.

CONCLUSION

CF is a rare complication following treatment for head and neck cancer but can be caused by neck dissection. Regular imaging examinations, including the clavicular region, are therefore needed before and after surgery to ensure the timely detection of CF.

Acanthopanax senticosus Harms extract causes G0/G1 cell cycle arrest and autophagy via inhibition of Rubicon in human liver cancer cells

Acanthopanax senticosus (Rupr. et Maxim) Harms (ASH), also known as Siberian ginseng or eleuthero, is a hardy shrub native to China, Korea, Russia and the northern region of Japan. ASH is used for the treatment of several diseases such as heart disease, hypertension, rheumatoid arthritis, allergies, chronic bronchitis, diabetes and cancer. In the present study, the inhibitory effect of the root extract of ASH (ASHE) on HuH-7 and HepG2 liver cancer cells was examined. ASHE suppressed liver cancer cell proliferation by inducing cell cycle arrest at the G0/G1 phase, as well as apoptosis, as indicated by the increased number of Annexin V and 7-AAD-positive cells. Furthermore, the expression of LC3-II, an autophagy marker, in these cells also increased post treatment with ASHE. LC3-II induction was further enhanced by co-treatment with chloroquine. Fluorescence and transmission electron micrographs of ASHE-treated liver cancer cells showed the presence of an increased number of autophagic vesicles. A decreased protein expression level of run domain Beclin-1-interacting and cysteine-rich domain-containing, an autophagy inhibitor, with no change in RUBCN mRNA expression was observed, indicating activation of the autophagosome-lysosome fusion step of autophagy. In conclusion, ASHE exerts cytostatic activity on liver cancer cells via both apoptosis and autophagy, and may serve as a potential therapeutic agent for management of liver cancer and autophagy-related diseases.

Direct reprogramming of epithelial cell rests of malassez into mesenchymal-like cells by epigenetic agents

The DNA demethylating agent, 5-Azacytidine (5Aza), and histone deacetylase inhibitor, valproic acid (Vpa), can improve the reprogramming efficiencies of pluripotent cells. This study aimed to examine the roles of 5Aza and Vpa in the dedifferentiation of epithelial cell rests of Malassez (ERM) into stem-like cells. Additionally, the ability of stem-like cells to differentiate into mesenchymal cells was evaluated. ERM was cultured in embryonic stem cell medium (ESCM) with 1 µM of 5Aza, or 2 mM of Vpa, or a combination of 5Aza and Vpa. The cells stimulated with both 5Aza and Vpa were named as progenitor-dedifferentiated into stem-like cells (Pro-DSLCs). The Pro-DSLCs cultured in ESCM alone for another week were named as DSLCs. The stem cell markers were significantly higher in the DSLCs than the controls (no additions). The mRNA and protein levels of the endothelial, mesenchymal stem, and osteogenic cell markers were significantly higher in the Pro-DSLCs and DSLCs than the controls. The combination of a demethylating agent and a deacetylated inhibitor induced the dedifferentiation of ERM into DSLCs. The Pro-DSLCs derived from ERM can be directly reprogrammed into mesenchymal-like cells without dedifferentiation into stem-like cells. Isolated ERM treated with epigenetic agents may be used for periodontal regeneration.

Case Report: Hidden Oral Squamous Cell Carcinoma in Oral Somatic Symptom Disorder

Background: Burning mouth syndrome (BMS) is a common condition of predominant oral pain without evident cause, that maxillofacial surgeons and otolaryngologists often refer to psychiatrists as somatic symptom disorder. In very rare cases, its typical burning symptom mimics those of other diseases in which serious fatal comorbidities may be missed. We encountered three rare cases of oral squamous cell carcinoma (OSCC) with the first symptom of burning tongue. Case Presentation: Case 1: A 68-year-old woman had burning pain on the left lingual margin for 8 years. Antidepressant treatment was not efficacious. Cytology and biopsy revealed OSCC. Case 2: A 70-year-old man had burning sensation and paralysis of the tongue for 6 months. Magnetic resonance imaging (MRI) revealed a 37 × 23-mm mass under the floor of the mouth and enlargement of lymph nodes on both sides. Case 3: A 90-year-old man had burning sensation of the tongue for 1 year. MRI revealed a 12 × 12-mm mass on the mandible with bone absorption. Conclusion: This case series suggests that psychiatrists must always be careful in regarding BMS as somatic symptom disorder and be cautious of the possibility of OSCC, especially in elderly patients.

Analysis of DNA methylation of E-cadherin and p16ink4a in oral lichen planus/oral lichenoid lesions

OBJECTIVES

Epigenetic phenomena are changes in gene expression not involving the DNA sequence. DNA methylation is a major occurrence underlying epigenetic changes in human cells. Although aberrant DNA methylation is well documented in malignant lesions, limited information has been shown on the involvement of DNA methylation in oral lichen planus and oral lichenoid lesions (OLP). The present study aimed to investigate DNA methylation of E-cadherin and p16 in OLP, and compare the findings with those in non-inflamed gingiva (Non), radicular cyst (RC), and oral squamous cell carcinoma (SCC).

MATERIALS AND METHODS

Paraffin-embedded surgical biopsy specimens were sliced, DNA was extracted, bisulfite treatment was applied, and methylation-specific polymerase chain reaction was performed. Immunohistochemistry was performed to observe the relative expression patterns of these genes.

RESULTS

E-cadherin was hypermethylated in OLP (p < 0.01), SCC (p < 0.01), and RC (p < 0.05), when compared with Non; DNA hypermethylation was confirmed in OLP and SCC when compared to Non and RC. Hypermethylation of p16^ink4a was observed only in SCC (p < 0.01).

CONCLUSION

DNA methylation levels of E-cadherin and p16^ink4a were significantly higher in OLP than in normal tissues, and may be associated with the pathogenesis and progression of the disease.

The potential of a surface pre-reacted glass root canal dressing for treating apical periodontitis in rats

AIM

To evaluate the efficacy of a prototype root canal dressing containing surface pre-reacted glass-ionomer (S-PRG) fillers on repairing induced periapical lesions in a rat model. Calcium hydroxide [Ca(OH)₂ ] was applied as a comparison in the healing process.

METHODOLOGY

The pulp chambers of the maxillary first molars in 64 male Wistar rats aged 16 weeks were opened to induce periapical lesions. After 28 days, the mesial canal of each tooth was prepared, irrigated with 2.5% sodium hypochlorite only (control group: irrigation) or followed by the respective dressing [Ca(OH)₂ group, irrigation + Ca(OH)₂ ; S-PRG group, irrigation + S-PRG] and restored with composite resin for 3 or 7 days (10/group). Four rats with healthy molars were used as blank controls. Descriptive analysis of the periapical radiographs, haematoxylin and eosin staining and immunohistochemical observation was performed 3 and 7 days after treatment. The periapical grey value, CD68 macrophages and osteoclasts (cathepsin-K) were quantified and statistically analysed with Tukey's honest significant difference test. A significant difference was achieved when P values were <0.05.

RESULTS

S-PRG and Ca(OH)₂ dressings were associated with increased periapical grey values and inhibited osteoclast activity at 3 and 7 days; a significant difference in radiographic results and the number of osteoclasts was obtained at 3 and 7 days compared with the control group (P < 0.05). Reparative tissue was observed histologically in the space of the periapical resorbed necrotic area after S-PRG and Ca(OH)₂ treatment for 3 and 7 days. The number of macrophages was significantly decreased at 3 and 7 days in the S-PRG and Ca(OH)₂ specimens when compared with the controls (P < 0.05).

CONCLUSIONS

In a rat experimental model, the S-PRG root canal dressing was comparable to Ca(OH)₂ in promoting the healing of experimentally induced periapical lesions. S-PRG paste has the potential to be used as an alternative intracanal dressing in teeth with apical periodontitis.

P. gingivalis Lipopolysaccharide Stimulates the Upregulated Expression of the Pancreatic Cancer-Related Genes Regenerating Islet-Derived 3 A/G in Mouse Pancreas

Although epidemiological studies have shown a relationship between periodontal disease and pancreatic cancer, the molecular mechanisms involved remain unclear. In this study, the effects of systemic administration of Porphyromonas gingivalis lipopolysaccharide (PG-LPS) on gene expression were comprehensively explored in mouse pancreas that did not demonstrate any signs of inflammation. PG-LPS was prepared in physiological saline and intraperitoneally administered to male mice at a concentration of 5 mg/kg every 3 days for 1 month. After extracting total RNA from the excised mice pancreas, a comprehensive DNA microarray analysis of gene expression was performed. Tissue specimens were also subjected to hematoxylin-eosin staining and immunohistochemistry using anti-regenerating islet-derived 3A and G (Reg3A/G) antibody. ImageJ software was used to quantify the area of Reg3A/G positive cells in pancreatic islets by binarizing image date followed by area extraction. The results were compared using Mann-Whitney U test. Data are presented as mean ± standard deviation (SD) with p < 0.05 considered as significant. Reg3G, a gene related to pancreatic cancer, was one of the 10 genes with the highest levels of expression in the pancreas stimulated with PG-LPS. The comprehensive analysis revealed a 73-fold increase in Reg3G expression level in the PG-LPS group when compared with the control group; in addition, the expression level of Reg3A was increased by 11-fold in the PG-LPS group. Image analysis showed that the ratio of Reg3A/G positive cells was higher in the PG-LPS group than the control. Immunostaining showed the presence of Reg3A/G-positive cells in the alpha-cell equivalent areas around the islets of Langerhans in the PG-LPS group. These results support the notion that periodontal disease may be a risk factor for pancreatic cancer.

Alteration of oral flora in Mongolian patients with Behçet's disease: a multicentre study

OBJECTIVES

Behçet's disease (BD) is characterised by repeated acute inflammatory attacks with aphthous ulcers of the oral mucosa, uveitis of the eyes, skin symptoms, and genital ulcers. Although its aetiology is still unknown, there is evidence of the involvement of oral bacteria in systemic diseases. Various types of oral bacteria may be involved in the development and progression of BD. The present study investigated alterations in the oral flora of patients with BD in Mongolia. We collected saliva samples from the Mongolian BD group and healthy control (HC) group, and the oral flora were analysed using next-generation sequencer (NGS).

METHODS

DNA was extracted from the unstimulated saliva samples from the 47 BD and 48 HC subjects. The DNA was amplified from the V3-V4 region of 16S rRNA using PCR, and the data were acquired using NGS. Based on the obtained data, we analysed the alpha diversity, beta diversity, and bacterial taxonomy of the salivary flora.

RESULTS

Beta diversity differed significantly between the BD and HC flora, but no significant differences were observed in alpha diversity. We found that the proportions of three genera - an S24-7 family unknown species, a mitochondria family unknown species, and Akkermansia species associated with IL-10 production - were significantly lower in the BD than in the HC group.

CONCLUSIONS

The reduced proportions of the S24-7 family and symbiotic Akkermansia species may be key phenomena in the oral flora of patients with BD.

Involvement of RNase 7 in the malignant potential of oral squamous cell carcinoma cells

RNase 7 is involved in the innate immunity of the oral epithelium. Variations in the expression levels of RNase 7 have been reported in cutaneous squamous cell carcinoma, but not in oral squamous cell carcinoma (OSCC). The present study investigated the expression levels of RNase 7 in OSCC and its role in the malignant potential of these cells. The localization of RNase 7 in OSCC tissue sections was determined via immunohistochemistry. Positive staining for RNase 7 was observed around the epithelial pearls and spinous cells of the OSCC tissues. Four different types of OSCC cell lines (OSC‑19, BSC‑OF, SAS, and HSC‑2) and a normal keratinocyte (HaCaT) were used. The mRNA and protein expression levels of RNase 7 were significantly higher in the OSCC cells compared to the HaCaT cells. Based on our hypothesis that high levels of RNase 7 expression may be involved in the malignant potential of OSCC cells, the effect of RNase 7 knockdown on both proliferation and invasion were evaluated by transfecting the cells with siRNA. Cell numbers, cell invasion, and MMP 9 expression levels were significantly higher in the siRNA‑BSC‑OF, ‑SAS, and ‑HSC‑2 cells compared to the BSC‑OF, SAS, and HSC‑2 cells. The extent of differentiation of the siRNA‑OSCC cells was examined using the differentiation and undifferentiation markers involucrin (INV) and K14, respectively. The expression level of K14 was significantly higher in the siRNA‑OSCC cells compared to the OSCC cells. Alternatively, HSC‑2 and SAS cells demonstrated higher expression levels of INV compared to the siRNA‑HSC‑2 and ‑SAS cells. These findings indicate that RNase 7 may contribute to the suppression of the malignant potential of OSCC.

Alteration of oral flora in betel quid chewers in Sri Lanka

BACKGROUND

Betel quid chewing is known as a crucial risk factor for oral diseases such as periodontal diseases, oral cancer, and precancerous lesions in Southeast Asian countries. Although abnormal oral bacterial flora may be linked to betel quid related-oral diseases such as oral cancer, precancerous lesions, and periodontal diseases, little information is available on alterations of their oral flora thus far. To identify these alterations, we analyzed the oral flora in betel quid chewers (BQC) and non-chewers (NC) in Sri Lanka.

METHODS

Samples obtained from buccal swabs of BQC and NC were analyzed with a next generation sequencer. Data were processed and analyzed using the QIIME software package. Mann-Whitney U test and Permutational multivariate analysis of variance were used for statistical analyses. P values < 0.05 were considered to be statistically significant.

RESULTS

In BQC, the proportion of periodontal pathogens including Actinomyces, Tannerella, and Prevotella was higher than that in NC (P < 0.05), while the proportion of cariogenic pathogens including Streptococcus, Lautropia, and Actinobacillus was lower than that in NC (P < 0.05). A statistically significant difference in Shannon index and PD Whole tree was observed between BQC and NC (P < 0.05). PCoA analysis detected different clusters in BQC and NC (P < 0.05).

CONCLUSION

The results suggested that betel quid chewing significantly altered oral flora. Adequate oral health care may help prevent BQC from developing bacterial pathogen-related oral diseases.

Chronic stress-induced elevation of IL-1β in the saliva and submandibular glands of mice

Psychological stress is involved in the development of various oral diseases. Alterations in the levels of cytokines in the saliva of patients with stress-related oral diseases have been reported. However, the inconsistencies in the results of these studies might be attributed to differences in the local and systemic factors in the oral cavities of the patients. We examined the effect of chronic stress on three major inflammatory cytokines Interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the saliva and salivary glands of chronically stressed mice. Six-week-old C57BL/6 J mice were randomly divided into a control and a stress group. The mice in stress group were exposed to 4 h of stress daily for 10 days and subsequently saliva, as well as the submandibular glands, were collected from both groups. The expression levels of cytokines in the saliva were examined by enzyme-linked immunosorbent assay. The submandibular glands were subjected to histopathological and mRNA expression analyses. IL-1β was significantly elevated in saliva of the chronic stressed mice. Furthermore, the mRNA expression levels of both IL-1β and IL-6 were significantly elevated in the submandibular gland of chronic stressed mice. IL-1β may be a potential salivary biomarker in response to chronic stress in mice.

DNA methylation of GJA1, BMP2 and BMP4 in a human cementoblast cell line induced by lipopolysaccharide

AIM

To examine DNA methylation of GJA1, BMP2 and BMP4 in human cementoblasts (HCEM) induced by lipopolysaccharide (LPS).

METHODOLOGY

HCEM were cultured in osteoinduction medium. After 24 h, Escherichia coli LPS (1 μg/mL) was added to the medium, which was changed every 2-3 days. Untreated samples were used as controls. Messenger RNA was extracted after 4 weeks, and quantitative real-time polymerase chain reaction (qRT-PCR) for GJA1, BMP2, BMP4 and DNMT1 was performed. Genomic DNA was extracted after 4 weeks, and quantitative methylation-specific polymerase chain reaction was carried out for GJA1, BMP2 and BMP4. To detect mineralization, alizarin red and alkaline phosphatase staining were performed. The cells were also treated with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5Aza) and examined. The significance of differences amongst groups was assessed using a two-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test with P < 0.05 being significant.

RESULTS

Decreased expression of mRNA was seen in GJA1, BMP2 and BMP4 after 4 weeks (P < 0.05). DNA hypermethylation was detected in GJA1, BMP2 and BMP4 (P < 0.05). Alizarin red staining and alkaline phosphatase staining revealed decreased mineralization levels in HCEM stimulated with LPS. 5Aza abolished the effects of DNA methylation in HCEM stimulated with LPS.

CONCLUSIONS

These results suggest that long-term LPS stimulation induces DNA methylation of GJA1, BMP2 and BMP4 in HCEM.

DNA hypermethylation of sirtuin 1 (SIRT1) caused by betel quid chewing-a possible predictive biomarker for malignant transformation

BACKGROUND

DNA hypermethylation of tumor suppressor genes is observed in precancerous lesions and oral cancer of individuals with the habits of betel quid (BQ) chewing. SIRT1 has been identified as playing a role in the maintenance of epithelial integrity, and its alteration is often related to carcinogenesis. However, the methylation and transcription status of SIRT1 in patients with BQ chewing-related oral cancer has not been investigated. We examined the methylation status of SIRT1 in paraffin-embedded tissue samples of oral squamous cell carcinoma (OSCC) obtained from BQ chewing and non-chewing patients and in tissue samples from healthy control subjects. In addition, we examined whether the hypermethylation of SIRT1 followed by its transcriptional downregulation in the human gingival epithelial cells could be caused by arecoline, a major component of BQ. Furthermore, we investigated the methylation status of SIRT1 in smear samples of macroscopically healthy buccal mucosa from subjects with a habit of BQ chewing.

RESULTS

SIRT1 was significantly hypermethylated in tissue samples of OSCC from BQ chewers and non-chewers than in oral mucosa from healthy control subjects. Results also showed that the hypermethylation level of SIRT1 was significantly higher in OSCC of patients with BQ chewing habits than in those of non-chewing habits (p < 0.05). Our in vitro model showed that hypermethylation is followed by downregulation of the transcriptional level of SIRT1 (p < 0.05). The methylation levels of SIRT1 in the smear samples obtained from BQ chewing individuals were significantly higher than those in the samples obtained from individuals that did not chew BQ. The duration of BQ chewing habits was correlated positively to the frequency of SIRT1 hypermethylation (p < 0.05).

CONCLUSIONS

Our results suggest that DNA hypermethylation of SIRT1 is involved in the occurrence of oral cancer in BQ chewing patients and that hypermethylation in the oral mucosa of BQ chewers could be a predictive marker for the occurrence of malignant transformation. This is the first report that showed DNA hypermethylation in clinically healthy oral epithelium of BQ chewers. Our study shows evidence that DNA hypermethylation may be an early event of oral carcinogenesis prior to observable clinical changes.

Control of protein function through oxidation and reduction of persulfidated states

Irreversible oxidation of Cys residues to sulfinic/sulfonic forms typically impairs protein function. We found that persulfidation (CysSSH) protects Cys from irreversible oxidative loss of function by the formation of CysSSO_1-3H derivatives that can subsequently be reduced back to native thiols. Reductive reactivation of oxidized persulfides by the thioredoxin system was demonstrated in albumin, Prx2, and PTP1B. In cells, this mechanism protects and regulates key proteins of signaling pathways, including Prx2, PTEN, PTP1B, HSP90, and KEAP1. Using quantitative mass spectrometry, we show that (i) CysSSH and CysSSO₃H species are abundant in mouse liver and enzymatically regulated by the glutathione and thioredoxin systems and (ii) deletion of the thioredoxin-related protein TRP14 in mice altered CysSSH levels on a subset of proteins, predicting a role for TRP14 in persulfide signaling. Furthermore, selenium supplementation, polysulfide treatment, or knockdown of TRP14 mediated cellular responses to EGF, suggesting a role for TrxR1/TRP14-regulated oxidative persulfidation in growth factor responsiveness.

Curcumin inhibits the expression of proinflammatory mediators and MMP-9 in gingival epithelial cells stimulated for a prolonged period with lipopolysaccharides derived from Porphyromonas gingivalis

Curcumin, a yellow phytochemical found in the rhizomes of Curcuma longa, has various biological effects, including anti-oxidant and anti-inflammatory activities. In the present study, we examined the effect of curcumin on the expression of inflammatory cytokines in human gingival epithelial progenitor cells (HGEPs) stimulated for a prolonged period with lipopolysaccharide (LPS) derived from Porphyromonas gingivalis. The cells were alternately cultured with LPS and/or curcumin every 3 days for 18 days. The expression levels of TNF-α, IL-1β, IL-6, TIMP-1, and MMP-9 in the HGEPs were evaluated by quantitative real-time polymerase chain reaction. Enzyme-linked immunosorbent assay was used to measure the concentrations of these five proteins in the supernatant and nuclear factor (NF)-κB in the nuclear extracts. Curcumin inhibited the mRNA expression levels of TNF-α, IL-1β, IL-6, and MMP-9 in HGEPs treated with curcumin over a prolonged period. Similarly, the expression levels of IL-1β, IL-6, and MMP-9 were decreased in the culture supernatants. NF-κB activity was also inhibited in the cells cultured with curcumin. In conclusion, these findings indicate that curcumin inhibits the expression of inflammatory cytokines and MMP-9 in primary gingival epithelial cells stimulated with P. gingivalis-derived LPS via NF-κB activation.

Immunohistochemical Localization of RNase 7 in Normal and Inflamed Oral Epithelia and Salivary Glands

RNase 7 is a skin-derived antimicrobial peptide expressed in various epithelial tissues. It is upregulated by stimulation with microbes and pro-inflammatory cytokines. Herein, we examined the expression levels of RNase 7 in tissues from normal and inflamed oral epithelia and salivary glands via immunohistochemistry. RNase 7 was expressed mainly in the surface layers of the parakeratinized and orthokeratinized oral epithelium. In addition, it was strongly and weakly expressed in oral lichen planus and radicular cysts, respectively. RNase 7 was constitutively expressed in salivary glands, particularly in the serous and duct cells. In the case of Sjogren’s syndrome, RNase 7 was strongly expressed in serous, ductal, and mucous cells in areas with lymphocytic infiltration. The localization patterns of RNase 7 were similar to those of other epithelial antimicrobial peptides, including beta-defensins. Thus, epithelial antimicrobial peptides may act against microbial infections in a coordinated manner in oral epithelia and salivary glands.

Current management strategies for the pain of elderly patients with burning mouth syndrome: a critical review

Burning Mouth Syndrome (BMS), a chronic intraoral burning sensation or dysesthesia without clinically evident causes, is one of the most common medically unexplained oral symptoms/syndromes. Even though the clinical features of BMS have been astonishingly common and consistent throughout the world for hundreds of years, BMS remains an enigma and has evolved to more intractable condition. In fact, there is a large and growing number of elderly BMS patients for whom the disease is accompanied by systemic diseases, in addition to aging physical change, which makes the diagnosis and treatment of BMS more difficult. Because the biggest barrier preventing us from finding the core pathophysiology and best therapy for BMS seems to be its heterogeneity, this syndrome remains challenging for clinicians. In this review, we discuss currently hopeful management strategies, including central neuromodulators (Tricyclic Antidepressants - TCAs, Serotonin, and Norepinephrine Reuptake Inhibitors - SNRIs, Selective Serotonin Reuptake Inhibitors - SSRIs, Clonazepam) and solutions for applying non-pharmacology approaches. Moreover, we also emphasize the important role of patient education and anxiety management to improve the patients’ quality of life. A combination of optimized medication with a short-term supportive psychotherapeutic approach might be a useful solution.

Sirtuin 1 and oral cancer

The sirtuins (SIRTs) are a family of highly conserved histone deacetylases (HDACs) consisting of seven members (SIRT1-SIRT7). Over the past few decades, SIRT1 has been the most extensively studied and garnered tremendous attention in the scientific community due to its emerging role in cancer biology. However, its biological role in the regulation of oral cancer is not yet fully understood. Owing to contradictory findings regarding the role of SIRT1 in oral cancer, debate about it continues. The present study discusses the biological roles and potential therapeutic implications of SIRT1 in precancerous oral lesions and oral cancer.

Adenomatous ductal proliferation/hyperplasia in the parotid gland associated without any other pathological lesions; a report and survey of the literatures

Adenomatous ductal proliferation/hyperplasia (ADP/H) is a rare hyperplastic condition of the salivary gland. It is mostly associated with other salivary gland pathologies such as tumors and inflammations, and is incidentally found in tissue sections during histopathological examinations of those diseases. Herein, we report a case of ADP/H in the parotid gland not associated with any other pathological lesions, and present a review of the literature on this condition. A 60-year-old Japanese female complained of swelling on the left side of parotid region. Clinical examination revealed a swelling on the lower lobe of the left parotid gland. The lesion was firm but non-tender and was not attached to adjacent structures. A clinical diagnosis of benign salivary gland tumor was reached, and surgical excision was performed under general anesthesia. Histopathological examination revealed an intact parotid gland capsule with isomorphic and basaloid cells within scanty cytoplasm. In addition, an admixture of hyperplasia and proliferation of the intercalated ducts, the presence of zymogen granules, the absence of solid nests, and a peripheral palisaded arrangement of the cells were observed. Based on these findings, a diagnosis of ADP/H was confirmed. ADP/H is a non-tumorous lesion; therefore, tumor involvement should be ruled out before the diagnosis is reached.

In vitro biofilm formation by Staphylococcus aureus isolated from wounds of hospital-admitted patients and their association with antimicrobial resistance

Introduction

Staphylococcus aureus including methicillin-resistant S. aureus (MRSA) has the propensity to form biofilms, and causes significant mortality and morbidity in the patients with wounds. Our aim was to study the in vitro biofilm-forming ability of S. aureus isolated from wounds of hospitalized patients and their association with antimicrobial resistance.

Materials and methods

Forty-three clinical isolates of S. aureus were obtained from 150 pus samples using standard microbiological techniques. Biofilm formation in these isolates was detected by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby–Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test.

Results

Biofilm formation was observed in 30 (69.8%) and 28 (65.1%) isolates of S. aureus via TCP method and TM, respectively. Biofilm-producing S. aureus exhibited a higher incidence of antimicrobial resistance when compared with the biofilm nonproducers (P<0.05). Importantly, 86.7% of biofilm-producing S. aureus were multidrug resistant (MDR), whereas all the biofilm nonproducers were non-MDR (P<0.05). Large proportions (43.3%) of biofilm producers were identified as MRSA; however, none of the biofilm nonproducers were found to be MRSA (P<0.05).

Conclusion

Both the in vitro methods showed that S. aureus isolated from wound infection of hospitalized patients have high degree of biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by S. aureus and their antimicrobial resistance profile may lead to the early treatment of the wound infection.

Bio-implant as a novel restoration for tooth loss

A dental implant is used to replace a missing tooth. Fixing the implant in its natural position requires the engineering of a substantial amount of conformal bone growth inside the implant socket, osseointegration. However, this conventional implant attachment does not include the periodontal ligament (PDL), which has a fundamental role in cushioning high mechanical loads. As a result, tooth implants have a shorter lifetime than the natural tooth and have a high chance of infections. We have engineered a "bio-implant" that provides a living PDL connection for titanium implants. The bio-implant consists of a hydroxyapatite coated titanium screw, ensheathed in cell sheets made from immortalized human periodontal cells. Bio-implants were transplanted into the upper first molar region of a tooth-extraction mouse model. Within 8 weeks the bio-implant generated fibrous connective tissue, a localised blood vessel network and new bone growth fused into the alveolar bone socket. The study presents a bio-implant engineered with human cells, specialised for the root connection, and resulted in the partial reconstruction of a naturalised tooth attachment complex (periodontium), consisting of all the principal tissue types, cementum, PDL and alveolar bone.

Cognitive behavioral therapy for psychosomatic problems in dental settings

Cognitive behavioral therapy (CBT) has been applied for various problems, including psychiatric diseases such as depression and anxiety, and for physical symptoms such as pain. It has also been applied for dental problems. Although the effect of CBTs on temporomandibular disorders and dental anxiety are well documented, its effectiveness on other types of oral symptoms remain unclear. Little information comparing the different types of CBTs in the dental setting is currently available. Because dental professionals are often expected to conduct CBTs in the dental setting, it is important to develop proper training programs for dental professionals.

In this review article, we demonstrate and discuss the application of CBTs for psychosomatic problems, including temporomandibular disorders, dental anxiety, burning mouth syndrome, and other oral complaints in dental settings.

Upregulated expression of MMP-9 in gingival epithelial cells induced by prolonged stimulation with arecoline

Betel quid chewing is implicated in the high prevalence of oral cancer in Southeast Asian countries. One of the major components of betel quid is arecoline. In the present study, in order to characterize the association between chronic arecoline stimulation and carcinogenesis the expression level of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in human gingival epithelial progenitor cells (HGEPs) stimulated with arecoline was assessed. The HGEPs were alternated between 3 days of incubation with arecoline (50 µg/ml), and 3 days without arecoline, for up to 30 days. The expression levels of the MMPs and TIMPs in the cells stimulated with arecoline were evaluated by reverse transcription-quantitative polymerase chain reaction at 18 and 30 days. The expression of MMP-9 mRNA in the experimental group was significantly increased compared with in the control group (P<0.01). No significant differences in the expression of MMP-2, TIMP-1 or TIMP-2 mRNA were observed between the experimental and control groups. Using an MMP-9 activity assay, the levels of MMP-9 activity in the experimental group were demonstrated to be significantly higher than in the control group (P<0.05). To investigate associated cellular signaling pathways, PDTC [a nuclear factor (NF)-κB/inhibitor of NF-κB (IκB) inhibitor], PD98059 [a mitogen-activated protein kinase kinase (MAPKK)1 and MAPKK2 inhibitor], SB203580 (a p38 MAPK inhibitor) and 5,15-DPP [a signal transduction and activator of transcription (STAT) 3 inhibitor] were used. All inhibitors decreased the extent of MMP-9 upregulation induced by stimulation with arecoline. Based on the data, it is hypothesized that MMP-9 activity may be involved in the pathological alterations of oral epithelium induced by betel quid chewing, and that the NF-κB/IκB, MAPK, p38 MAPK and STAT3 signaling pathways may be involved in the production of MMP-9 induced by betel quid chewing.

Osseous choristoma of the tongue: two case reports

Background

Osseous choristoma is a very rare, benign lesion in the maxillofacial region. It appears as a benign mass of normally matured bony tissue covered by the normal epithelium of the tongue. It is usually seen in front of the foramen cecum of the tongue. Surgical excision is the treatment of choice with an excellent prognosis and there have been very few cases of recurrence.

Case presentation

Here we present two cases of osseous choristoma on the dorsum of the tongue. Case 1 was a 15-year-old Japanese girl who presented with a painless but gradually growing swelling on the dorsum of her tongue approximately 1 year before her admission. Case 2 was a 21-year-old Japanese woman with a complaint of pain in the lower left, posterior side of her mouth. Histological findings showed that both lesions were composed of well-organized, mature, compact bone beneath the oral mucosal membrane. Subsequent to simple surgical excision, no recurrence of the lesions was observed after the follow-up period. Previous literatures have proposed both malformation and trauma hypotheses as the etiopathologies of osseous choristoma. However, the histopathological findings of the two cases in the present study do not support the trauma hypothesis.

Conclusions

Although osseous choristoma is clinically a benign condition, the underlying histopathological processes are important. The outcome of aberrant formation of calcified tissue in the vicinity of vital structures such as nerves and blood vessels may be of clinical significance.