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Osteomyelitis of the jaw is a severe inflammatory disorder that affects bones, and it is categorized into two main types: chronic bacterial and nonbacterial osteomyelitis. Although previous studies have investigated the association between these diseases and the oral microbiome, the specific taxa associated with each disease remain unknown. In this study, we conducted shotgun metagenome sequencing (≥10 Gb from ≥66,395,670 reads per sample) of bulk DNA extracted from saliva obtained from patients with chronic bacterial osteomyelitis (N = 5) and chronic nonbacterial osteomyelitis (N = 10). We then compared the taxonomic composition of the metagenome in terms of both taxonomic and sequence abundances with that of healthy controls (N = 5). Taxonomic profiling revealed a statistically significant increase in both the taxonomic and sequence abundance of Mogibacterium in cases of chronic bacterial osteomyelitis; however, such enrichment was not observed in chronic nonbacterial osteomyelitis. We also compared a previously reported core saliva microbiome (59 genera) with our data and found that out of the 74 genera detected in this study, 47 (including Mogibacterium) were not included in the previous meta-analysis. Additionally, we analyzed a core-genome tree of Mogibacterium from chronic bacterial osteomyelitis and healthy control samples along with a reference complete genome and found that Mogibacterium from both groups was indistinguishable at the core-genome and pan-genome levels. Although limited by the small sample size, our study provides novel evidence of a significant increase in Mogibacterium abundance in the chronic bacterial osteomyelitis group. Moreover, our study presents a comparative analysis of the taxonomic and sequence abundances of all genera detected using deep salivary shotgun metagenome data. The distinct enrichment of Mogibacterium suggests its potential as a marker to distinguish between patients with chronic nonbacterial osteomyelitis and chronic bacterial osteomyelitis, particularly at the early stages when differences are unclear. [ABSTRACT FROM AUTHOR]

In cancer treatment, perioperative oral functional management is used as a part of supportive care. Its main objectives are as follows: (1) preventing and reducing adverse events, (2) maintaining or improving nutritional status, (3) improving cancer treatment outcomes, (4) maintaining or improving quality of life, (5) providing high quality medical care through comprehensive oral care, (6) controlling odontogenic foci of infection, and (7) maintaining or improving oral function. A literature search was conducted using the electronic databases of Medical Journal and PubMed. Electronic database searches were performed using various combinations of the following key words: cancer, surgery, treatment, chemotherapy, radiotherapy and dental disease, oral care, oral management, dental intervention, oral health, dental care, and dental management. The selection of literature for inclusion in the review was restricted to dental management of patients receiving cancer treatment. In the course of the literature review, hand searches were also added as needed. The guideline was developed by summarizing the results of the review. Based on a review of the literature on the management of dental foci of infection in the oral functional management of patients undergoing cancer treatment, a guideline was developed by summarizing the results of the review. This report is a secondary publication of our previous review report "J. Stomatol. Soc. 70(4): 279–289. Dec 2021." [ABSTRACT FROM AUTHOR]

Glandular odontogenic cyst (GOC) is a rare odontogenic cyst with aggressive behavior. A 50-year-old Japanese man presented with pain and swelling of the mental region of the mandible. Panoramic radiography showed a clearly bordered radiolucent lesion extending from the alveolar to cortical bone of the mandible. The clinical diagnosis was an odontogenic tumor (e.g., ameloblastoma), and an incisional biopsy was performed. The histopathological diagnosis was GOC, and extirpation and tooth extraction were performed under general anesthesia. Because bone destruction is evident in patients with a huge GOC, it is important to differentiate these cysts from intraosseous mucoepidermoid carcinoma. Therefore, we analyzed the GOC for the presence of the CRTC1/3-MAML2 fusion gene and found it to be negative. The patient had developed no recurrence of the GOC at the time of following. [ABSTRACT FROM AUTHOR]

Simple Summary: There are many aspects of oral cancer invasion and metastasis that remain to be elucidated. It has been suggested that chronic inflammation caused by bacteria may be a cause of carcinogenesis, invasion, and metastasis. PD-L1 expression is associated with lymph node metastasis and poor prognosis in several cancers. Lipopolysaccharide (LPS) from Porphyromonas gingivalis, which is known to be the main cause of bacterial periodontitis, induced PD-L1 expression and partial epithelial–mesenchymal transition (pEMT) expression in oral cancer cells. Moreover, we identified PD-L1 expression within the exosomes of oral cancer cells. Exosomes may function as carriers of PD-L1. Background: Expression of programmed death ligand-1 (PD-L1) is related to the prognosis of many solid malignancies, including oral squamous cell carcinoma (OSCC), but the mechanism of PD-L1 induction remains obscure. In this study, we examined the expression of PD-L1 and partial epithelial–mesenchymal transition (pEMT) induced by bacterial lipopolysaccharide (LPS) in OSCC. Methods: The expression of Toll-like receptor 4 (TLR4) recognizing LPS in OSCC cell lines was analyzed. Moreover, the induction of PD-L1 expression by Porphyromonas gingivalis (P.g) or Escherichia coli (E. coli) LPS and EMT was analyzed by western blotting and RT-PCR. Morphology, proliferation, migration, and invasion capacities were examined upon addition of LPS. PD-L1 within EXOs was examined. Results: PD-L1 expression and pEMT induced by LPS of P.g or E. coli in TLR4-expressing OSCC cell lines were observed. Addition of LPS did not change migration, proliferation, or cell morphology, but increased invasive ability. Moreover, higher expression of PD-L1 was observed in OSCC EXOs with LPS. Conclusion: Oral bacterial LPS is involved in enhanced invasive potential in OSCC cells, causing PD-L1 expression and induction of pEMT. The enhancement of PD-L1 expression after addition of LPS may be mediated by EXOs. [ABSTRACT FROM AUTHOR]

Simple Summary: There is still limited knowledge of the critical pathogenic processes by which HPV16 induces oral carcinogenesis. Therefore, we aimed to illuminate the oncogenic role of HPV16 in the context of oral squamous cell carcinomas (OSCCs). Using human tongue keratinocyte cells, we demonstrated that HPV16 E6 promotes LTα1β2 and LTβR expression, thus promoting the lymphotoxin signaling pathway and leading to suppression of the transporter associated with the antigen-processing complex (TAPs; TAP1 and TAP2). Additionally, in vitro, we also demonstrated regulation of the antigenic peptide-loaded machinery in HPV-infected OSCC tissues through analysis of the transcriptomic profiles of the head and neck squamous cell carcinoma (HNSCC) cohort from the TCGA database, which was validated using fresh biopsied specimens. Thus, our study enhances the proposed functional role of HPV16 E6-associated immune-evasive properties in oral epithelial cells, revealing a possible mechanism underlying the development of HPV-mediated OSCCs. Infection by high-risk human papillomaviruses (hrHPVs), including HPV type 16 (HPV16), is a major risk factor for oral squamous cell carcinomas (OSCCs). However, the pathogenic mechanism by which hrHPVs promote oral carcinogenesis remains to be elucidated. Here, we demonstrated that the suppression of a transporter associated with the antigen-processing complex (TAPs; TAP1 and TAP2), which is a key molecule in the transportation of viral antigenic peptides into MHC class-I cells, is affected by the E6 protein of HPV16. Mechanistically, HPV-mediated immune evasion is principally mediated via the signal-transduction network of a lymphotoxin (LT) pathway, in particular LTα1β2 and LTβR. Our analysis of transcriptomic data from an HNSCC cohort from the Cancer Genome Atlas (TCGA) indicated that expression of TAP genes, particularly TAP2, was downregulated in HPV-infected cases. We further demonstrated that LTα1β2 and LTβR were upregulated, which was negatively correlated with TAP1 and TAP2 expression in HPV-positive clinical OSCC samples. Taken together, our findings imply that HPV16 E6 regulates the machinery of the antigenic peptide-loading system and helps to clarify the role of oncogenic viruses in the context of oral carcinoma. [ABSTRACT FROM AUTHOR]

We report here a case of mandibular osteomyelitis in a 63-year-old female in which quantitative values determined using bone SPECT/CT were useful to evaluate response to antibiotic therapy, hyperbaric oxygen therapy, and sequestomy. After finishing therapy, the chief complaints were well relieved, and posttreatment Tc-99m HMDP bone SPECT/CT examination showed decreased uptake. The maximum standardized uptake value (SUV), peak SUV, mean SUV, metabolic bone volume, and total bone uptake of the untreated lesion were 6.26, 5.16, 3.97, and 11.86 mL and 42.21, respectively, which were decreased to 4.65, 3.90, 2.77, and 9.67 mL and 26.80, respectively, following hyperbaric oxygen therapy and antibiotic administration, and were moreover decreased to 4.28, 3.67, 2.75, and 6.24 mL and 17.19, respectively, after sequestomy. In comparison with pretreatment situation, those parameters were decreased by −25.7, −24.4, −30.2, −18.5, and −36.5%, respectively, following hyperbaric oxygen therapy and antibiotic administration, and moreover by −31.6, −28.9, −30.7, −47.4, and −59.3, respectively, after sequestomy, likely reflecting treatment response. Quantitative bone SPECT/CT may be useful to evaluate bone inflammatory activity and treatment response in a patient with mandibular osteomyelitis. [ABSTRACT FROM AUTHOR]

Mucoceles usually originate from minor salivary glands. They rarely develop from the submandibular gland, and the location of all previously reported submandibular gland mucoceles is extra‐glandular. To the best of our knowledge, no reports have described a localized mucocele occurring within the submandibular gland. We herein present an extremely rare case of a localized mucocele including a sialolith that occurred in the submandibular gland. Extirpation of the submandibular gland including both the mucocele and sialolith was performed, and no postoperative complications occurred during the 2‐year follow‐up. [ABSTRACT FROM AUTHOR]

Bisphosphonate-related osteonecrosis of the jaw (BRONJ), characterized by refractory bone exposure, has recently emerged as a serious side effect of bisphosphonate (BPs) treatment. We discuss novel insights that may help to improve the efficacy of BRONJ treatment and prevention. Our report highlights the following: (1) The presence of exposed bone in patients taking BPs does not necessarily reflect BRONJ, and diagnoses of oral ulceration with bone sequestration and malignancy must be excluded. (2) Osteonecrosis type of BRONJ is difficult to avoid using preventive dental measures alone. However, as with osteomyelitis type of BRONJ, preventive dental measures are indispensable for reducing the risk of secondary infection and disease progression. (3) The importance of tooth extraction as a risk factor for BRONJ among patients taking BPs has been overstated, particularly when they are administered at low doses. Delaying tooth extraction may increase the risk for the onset and progression of osteomyelitic BRONJ. (4) In patients taking low doses of BPs, dental implant surgery is not necessarily contraindicated if there are no other risk factors, such as combined use of corticosteroids or concomitant diabetes. However, the risk of BRONJ due to peri-implantitis must be explained when obtaining patient consent. [ABSTRACT FROM AUTHOR]

Osteoclasts (OCs) differentiate from monocyte/macrophage-lineage hematopoietic precursor cells, which are known as OC precursors (OCPs). Several studies have investigated cell chemotaxis in the bone microenvironment; however, OCP migration ability in the bone microenvironment during OC differentiation is yet to be elucidated. As an initial investigation of this characteristic, the present study aimed to determine the effects of transforming growth factor (TGF)-β1 on OCP migration in vitro. Pre-osteoclastic RAW264.7 cells were cultured with and without TGF-β1 (2, 5 or 20 ng/ml), receptor activator of NF-κB ligand (RANKL; 50 ng/ml), and/or SB431542 (10 µM), a potent and specific inhibitor of TGF-β1 receptor kinase activity. Cell proliferation was significantly inhibited in the presence of TGF-β1 for 3 days, and the effect was reversed by SB431542. Tartrate-resistant acid phosphatase (TRAP) activity in RAW264.7 cells was significantly increased by RANKL treatment, compared with TRAP activity in control cells on day 3. The highest TRAP activity in RAW264.7 cells was induced by the combined treatment with TGF-β1 (2 ng/ml) and RANKL. When TGF-β1 signaling was inhibited by addition of SB431542 to the medium during culture, OC differentiation was notably suppressed. These findings suggest that TGF-β1 accelerates RANKL-induced OC differentiation, but does not act in a dose-dependent manner. The migration of RAW264.7 cells was promoted at 24 h, but was suppressed at 72 h, during RANKL-induced osteoclast differentiation in the presence of TGF-β1. These results were accompanied with the increased expression of small G-proteins, RhoA and Rac, at 24 h, but their expression decreased at 72 h. RAW264.7 cells treated with TGF-β1 for 24 h underwent morphological changes, from round to polygonal morphology. Furthermore, protrusions were completely lost and the cell morphology reverted from polygonal to round after TGF-β1 treatment for 72 h. Therefore, our findings indicated that OCP migration may be modified by differentiation in vitro. [ABSTRACT FROM AUTHOR]

Oral lichen planus (OLP) or chronic inflammation is a risk factor for oral squamous cell carcinoma (OSCC). We report a case of OSCC derived from OLP around dental implant (DI) in a 78‐year‐old woman. First incisional biopsy of this region was diagnosed as OLP. Epidermal hyperplasia was revealed in a second biopsy performed after 1 year and 4 months. After 8 months, OSCC occurred on the same site and surgical treatment was successfully performed. This case may present a process of malignant conversion from OLP to OSCC via epithelial hyperplasia. There is a possibility that periimplantitis was involved in this change. [ABSTRACT FROM AUTHOR]

Aging is a significant risk factor for the development of bisphosphonate-related osteonecrosis of the jaws (BRONJ). Accumulating evidence suggests that bone aging is associated with oxidative stress (OS), and OS is associated with osteonecrosis. To elucidate the mechanisms of the onset of BRONJ, the present study focused on OS and the effects of treatment with the pro-oxidant DL-buthionine-(S,R)-sulfoximine (BSO), an oxidative stressor, on healing of a surgically induced penetrating injury of the palate. Six-week-old C57BL/6J mice were randomly divided into four groups (n=5 each) and treated with or without zoledronic acid (ZOL) and with or without BSO (experimental groups: ZOL, BSO, and ZOL+BSO; control group: saline solution). A penetrating injury of the midline palate was surgically created using a root elevator. ZOL (250 µg/kg/day) was injected intraperitoneally every day from 7 days prior to the surgical treatment to 4 days following the surgical treatment. BSO (500 µg/kg/day) was administered 7 days prior to the surgical treatment as a single intraperitoneal injection. The maxillae were harvested at 5 days following the surgical treatment for histological and histochemical studies. The presence of empty osteocyte lacunae in the palatal bone was increased by ZOL and BSO treatment. The highest number of empty osteocyte lacunae was observed in the ZOL+BSO group. The number of tartrate-resistant acid phosphatase-positive cells was decreased by ZOL treatment and increased by BSO treatment. The number of canaliculi per osteocyte lacuna was significantly decreased by BSO treatment. The mineral apposition rate was significantly lower in the treatment groups than the control group. Bisphosphonates and OS suppressed bone turnover. The present study has demonstrated that BSO treatment affects osteocytes, and OS in osteocytes exacerbates impairment of the osteocytic canalicular networks. As a result, bisphosphonates and OS may induce osteonecrosis following invasive dentoalveolar surgery. OS has been identified as an additional risk factor for the development of BRONJ. [ABSTRACT FROM AUTHOR]

Cytomegaloviruses (CMVs) encode cellular homologs to evade host immune functions. In this study, we analyzed the roles of GP33, a guinea pig CMV (GPCMV)-encoded G protein-coupled receptor (GPCR) homolog, in cellular signaling, viral growth and pathogenesis. The cDNA structure of GP33 was determined by RACE. The effects of GP33 on some signaling pathways were analyzed in transient transfection assays. The redET two-step recombination system for a BAC containing the GPCMV genome was used to construct a mutant GPCMV containing an early stop codon in the GP33 gene (Δ33) and a rescued GPCMV (r33). We found the following: 1) GP33 activated the CRE- and NFAT-, but not the NFκB-mediated signaling pathway. 2) GP33 was dispensable for infection in tissue cultures and in normal animals. 3) In pregnant animals, viral loads of r33 in the livers, lungs, spleens, and placentas at 6 days post-infection were higher than those of Δ33, although the viruses were cleared by 3 weeks post-infection. 4) The presence of GP33 was associated with frequent lesions, including alveolar hemorrhage in the lungs, and inflammation in the lungs, livers, and spleens of the dams. Our findings suggest that GP33 has critical roles in the pathogenesis of GPCMV during pregnancy. We hypothesize that GP33-mediated signaling activates cytokine secretion from the infected cells, which results in inflammation in some of the maternal organs and the placentas. Alternatively, GP33 may facilitate transient inflammation that is induced by the chemokine network specific to the pregnancy. [ABSTRACT FROM AUTHOR]

Granulocyte colony-stimulating factor (G-CSF) regulates the survival, proliferation and differentiation of all cells in the neutrophil lineage, and is consequently used for neutropenic conditions. Upon G-CSF administration, osteoblasts and osteocytes are suppressed, and the support system allowing hematopoietic stem cells to remain in the microenvironment is diminished. The present study focused on and investigated G-CSF as a regulatory factor of bone remodeling. The aim of the present study was to investigate the effect of G-CSF administration on the bone healing of tooth extraction sockets. Significant differences in the bone volume fraction, and trabecular separation of the proximal femurs and alveolar septa were observed between the G-CSF and control (saline-treated) groups. The trabecular bone of the femur and alveolar septa was reduced in the G-CSF group compared with that in the control group. In addition, serum procollagen type 1 N-terminal propeptide levels, a marker of bone formation, were lower in the G-CSF group compared with in the control group. Fibrous connective tissues and immature bone were observed in the extraction socket, and bone healing was delayed in the G-CSF group compared with that in the control group. The bone area in the extraction socket 6 days after tooth extraction was significantly smaller in the G-CSF group (23.6%) than that in the control group (45.1%). Furthermore, G-CSF administration reduced the number of canaliculi per osteocyte and inhibited the connection of osteocyte networks. Consequently, osteoblast activation was inhibited and bone remodeling changed to a state of low bone turnover in the G-CSG group. Analysis of bone formation parameters revealed that the G-CSF group exhibited a lower mineral apposition rate compared with in the control group. In conclusion, these findings indicated that G-CSF may delay bone healing of the socket after tooth extraction. [ABSTRACT FROM AUTHOR]

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the major and minor salivary glands. Surgical resection is the only curative treatment and there is no effective post-operative therapy for MEC. The present study reports an Institutional Review Board-approved case of a 45-year-old Japanese female diagnosed with low-grade MEC in the hard palate. Radical resection, supraomohyoid neck dissection and antero-lateral thigh flap reconstruction was performed. A MEC cell line was then established from the resected tumor tissue. Short tandem repeat profiling confirmed the origin and authenticity of the cell line, that harbors a CRTC1-MAML2 translocation, which is frequently observed in MEC. Amphiregulin (AREG), identified as one of the targets of the CRTC1-MAML2 fusion gene, was expressed in the cell line. The AREG receptor, epidermal growth factor receptor (EGFR) was also highly phosphorylated. The results predicted that AREG-EGFR signaling, which is required for tumor growth and survival, might be activated in the cell line in a cell-autonomous manner. As AREG expression is associated with EGFR-targeted drug resistance, this cell line might assist with the identification of novel strategies for MEC treatment. [ABSTRACT FROM AUTHOR]

Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is inherited in an autosomal dominant mode, and is characterized by a combination of developmental abnormalities and predisposition to form a variety of tumors. The hedgehog receptor Patched1 (PTCH1) has been identified as the gene mutated in NBCCS. We analyzed PTCH1 in two familial and three sporadic Japanese NBCCS cases, and identified five germline mutations in PTCH1. Two cases have a nonsense mutation (c.3058C>T and c.2760C>A), one a splice site mutation (c.584+2T>G), one a 1 bp insertion (c.2712_2713insA) and one a 1 bp deletion (c.980Gdel). All mutations induce truncation of the PTCH1 protein or could induce nonsense-mediated mRNA decay. The 11-year-old male patient with splice-site mutation (c.584+2T>G) had medulloblastoma (MB) at the age of 1 year. This is the first NBCCS patient with molecularly defined MB in Japan. [ABSTRACT FROM AUTHOR]

Background. Despite recent advances in the diagnosis and treatment of oral carcinoma, outcomes remain disappointing. The identification of new prognostic factors is necessary to improve survival. To determine the prognostic significance of cyclooxygenase (COX)-2 and DNA topoisomerase (DNA-Topo) IIα expression in patients with oral carcinoma, we immunohistochemically examined these enzymes and studied their relation to overall 5-year survival. Methods. Surgical specimens were obtained from 160 patients with oral carcinoma, 80 with and 80 without regional lymph node metastasis. The specimens were immunostained for COX-2 and DNA-Topo IIα as an index of cell proliferative activity. COX-2 immunoreactivity and clinicopathological data were analyzed, and 5-year survival was calculated by the Kaplan-Meier method. Results. COX-2 expression in primary lesions was higher in cases with lymph node metastasis than in those without lymph node metastasis. An increase in tumor size was associated with increased COX-2 expression. In most cases with lymph node metastasis, COX-2 expression was higher in metastatic lesions than in primary lesions. As COX-2 expression increased, the DNA-Topo IIα labeling index significantly increased and the overall 5-year survival rate decreased. Conclusion. Expression of COX-2 and DNA-Topo IIα were related to lymph node metastasis, cell proliferative activity, and overall 5-year survival rate in oral carcinoma. These enzymes may therefore be valuable diagnostic and prognostic indices in oral carcinoma. © 2007 Wiley Periodicals, Inc. Head Neck, 2007 [ABSTRACT FROM AUTHOR]

Objective: It is well known that small cell neuroendocrine carcinoma (SNEC) arising at extrapulmonary sites has a poor prognosis and an interesting biological characterization. To understand biological characterization and elucidation of the origin of the histogenesis of SNEC, we report the establishment of a new SNEC cell line and characteristics of neuroendocrine properties including neuronal differentiation by treatment with dibutyryl cyclic AMP (db-cAMP). Methods: We established a new cell line (SNEC-MI) derived from SNEC of the maxillary sinus by a modified spill-out method, and verified neuroendocrine properties including neuronal differentiation by immunocytochemical and immunoblotting methods. Results: The established cell line showed spherical or spindle shape in monolayer culture and was positive for neuron-specific enolase (NSE), neuronal cell adhesion protein (N-CAM, CD56) and gastrin-releasing peptide. NSE was also demonstrated in the cultured medium and dense-core neuroendocrine granules were detected ultrastructurally in the cytoplasm. Treatment of cells with db-cAMP markedly induced the development and elongation of neuronal processes, which formed a netlike arrangement. Characterization of these elongated neuronal processes revealed them immunoreacting intensely with high molecular-weight neurofilament, and a time-dependent increase of microtubule-associated protein-2 in cell lysates. Conclusions: These findings indicated that this cell line possesses the capability to differentiate into neuronal cells, and supported the hypothesis that extrapulmonary SNEC might be derived from a pluripotent stem cell. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aging cells not only cease growing, but also secrete various proteins such as inflammatory cytokines. This secretory phenomenon is known as the senescence-associated secretory phenotype (SASP). The aim of the present study was to elucidate the effects of senescence on the differentiation of osteoclast precursors (OCPs) and corresponding SASP. RAW264.7 cells were used as OCPs and were cultured to passage (P)5, P10 and P20. Cell proliferation assays, senescence-associated β-galactosidase staining and telomere length quantification were subsequently performed, and it was revealed that replicative senescence was induced at P20. In addition, the level of tartrate-resistant acid phosphatase activity in P20 cells treated with receptor activator of nuclear factor-κB ligand was significantly lower than that in P5 and P10 cells. The SASP factors interleukin-6, tumour necrosis factor-α and nitric oxide were significantly increased in P20 culture supernatants compared with those in P5 and P10 supernatants. Furthermore, the number of exosomes at P20 was increased compared with that at P5 and P10, and inducible nitric oxide synthase (iNOS) was expressed in exosomes at P20, but not in exosomes at P5. In conclusion, the present study revealed that senescent RAW264.7 cells exhibit increased expression of SASP factors and release iNOS in exosomes. [ABSTRACT FROM AUTHOR]

Abstract: Basal cell carcinoma (BCC) is the most common skin cancer. Its occurrence in the oral mucosa is extremely rare. We report the clinical course of BCC arising in the inferior surface of the tongue. We performed a super selective intra-arterial chemotherapy combined with radiotherapy for this case. Local tumor response showed CR, and no recurrence was seen after the treatment. [Copyright &y& Elsevier]