TRPV4 mediates IL-1-induced Ca2+ signaling, ERK activation and MMP expression.

Ca2+ permeation through TRPV4 in fibroblasts is associated with pathological matrix degradation. In human gingival fibroblasts, IL-1ß binding to its signaling receptor (IL-1R1) induces activation of extracellular regulated kinase (ERK) and MMP1 expression, processes that require Ca2+ flux across the plasma membrane. It is not known how IL-1R1, which does not conduct Ca2+, generates Ca2+ signals in response to IL-1. We examined whether TRPV4 mediates the Ca2+ fluxes required for ERK signaling in IL-1 stimulated gingival fibroblasts. TRPV4 was immunostained in fibroblasts of human gingival connective tissue and in focal adhesions of cultured mouse gingival fibroblasts. Human gingival fibroblasts treated with IL-1ß showed no change of TRPV4 expression but there was increased MMP1 expression. In mouse, gingival fibroblasts expressing TRPV4, IL-1 strongly increased [Ca2+]i. Pre-incubation of cells with IL-1 Receptor Antagonist blocked Ca2+ entry induced by IL-1 or the TRPV4 agonist GSK101. Knockout of TRPV4 or expression of a non-Ca2+-conducting TRPV4 pore-mutant or pre-incubation with the TRPV4 inhibitor RN1734, blocked IL-1-induced Ca2+ transients and expression of the mouse interstitial collagenase, MMP13. Treatment of mouse gingival fibroblasts with GSK101 phenocopied Ca2+ and ERK responses induced by IL-1; these responses were absent in TRPV4-null cells or cells expressing a non-conducting TRPV4 pore-mutant. Immunostained IL-1R1 localized with TRPV4 in adhesions within cell extensions. While TRPV4 immunoprecipitates analyzed by mass spectrometry showed no association with IL-1R1, TRPV4 associated with Src-related proteins and Src co-immunoprecipitated with TRPV4. Src inhibition reduced IL-1-induced Ca2+ responses. The functional linkage of TRPV4 with IL-1R1 expands its repertoire of innate immune signaling processes by mediating IL-1-driven Ca2+ responses that drive matrix remodeling in fibroblasts. Thus, inhibiting TRPV4 activity may provide a new pharmacological approach for blunting matrix degradation in inflammatory diseases.

TRPV4 regulates ß1 integrin-mediated cell-matrix adhesions and collagen remodeling.

Transient Receptor Potential Vanilloid-type 4 (TRPV4) is a mechanosensitive, Ca2+ -permeable plasma membrane channel that associates with focal adhesions, influences collagen remodeling, and is associated with fibrotic processes through undefined mechanisms. While TRPV4 is known to be activated by mechanical forces transmitted through collagen adhesion receptors containing the ß1 integrin, it is not understood whether TRPV4 affects matrix remodeling by altering ß1 integrin expression and function. We tested the hypothesis that TRPV4 regulates collagen remodeling through its impact on the ß1 integrin in cell-matrix adhesions. In cultured fibroblasts derived from mouse gingival connective tissues, which exhibit very rapid collagen turnover, we found that higher TRPV4 expression is associated with reduced ß1 integrin abundance and adhesion to collagen, reduced focal adhesion size and total adhesion area, and reduced alignment and compaction of extracellular fibrillar collagen. The reduction of ß1 integrin expression mediated by TRPV4 is associated with the upregulation of miRNAs that target ß1 integrin mRNA. Our data suggest a novel mechanism by which TRPV4 modulates collagen remodeling through post-transcriptional downregulation of ß1 integrin expression and function.

High-Fat Diet Influences Dendritic Cells and T-Cell Infiltration in Apical Periodontitis in Mice.

INTRODUCTION: Diet-induced metabolic syndrome may influence the progression and healing of apical periodontitis (AP). The aim of this study was to evaluate the inflammatory immune response of dendritic cells (DCs) and T helper (Th) cells in normal versus obese mice with AP. METHODS: Twenty male C57BL/6 mice were divided into 2 groups: normal chow (NC) and high-fat diet (HFD) for 12 wk. AP was induced in both groups by creating pulp exposure of the right first maxillary molar to the oral environment. Contralateral first molars from each mouse were used as a control. The animal's body mass was recorded on a weekly basis, and they were euthanized after 30 d. The maxillae were removed and processed for micro-computed tomography (micro-CT), histologic analysis, and immunofluorescence staining for DCs (CD11c), Th17 (IL-17A), and T regulatory cells (FOXP3 and IL-10). Different groups were analyzed by Mann-Whitney U test, Student t test, and ordinary 1-way analysis of variance followed by Tukey's multiple comparisons test. The level of significance (α) was set at 0.05. RESULTS: The HFD group showed larger AP lesions than the NC group from micro-CT analysis. For the NC group, induction of AP significantly increased immune cell infiltration when compared with control. HFD showed increased DCs and Th17 infiltration in the control group without AP. In addition, there was no significant change in the amount of DCs and Th17 in the HFD-AP group when compared with the NC-AP and HFD-control groups. CONCLUSIONS: HFD resulted in an increased immune cell infiltration in the periapical area without AP. Despite the larger AP lesion observed in HFD-AP than that of NC-AP, the amount of infiltrated inflammatory cells did not differ significantly. The results of this study suggest that the DCs and Th17 inflammatory pathways are affected by HFD in the periapical region, but their contribution toward AP complicated by metabolic syndrome requires further investigation.

Deciphering 3D periodontal fibroblast-macrophage crosstalk in bioactive nanoparticle-guided immunomodulation for treating traumatic dental avulsion.

Prolonged extra-oral period in dental avulsion is often associated with loss of viability of Periodontal fibroblasts (PDLF) and increased risk of ankylosis. Root surface treatment with bioactive agents to reduce the risk of ankylosis can be a potential strategy. The objective of the study was to investigate the impact of an engineered chitosan nanoparticles (CSNP), photosensitizer Rose Bengal (RB) functionalized CSNP (CSRB) and sustained dexamethasone (CSDEX) releasing CSNP for application in management of delayed replantation of avulsed teeth. The 3D PDLF-macrophage (Mϕ) collagen model was developed and exposed to LPS, MCSF, RANKL with and without CSDEX/CSNP. Immunofluorescence and cytokine analysis was done at 2 and 7 days to assess cellular interactions. Maxillary right incisors in male Wistar rats were extracted, exposed to extraoral dry or LPS for 1 h and treated with or without CSDEX/CSRB for 1 min before replantation. Rats were euthanized after 21 days for micro-CT, TRAP, and immunofluorescence analysis. CSDEX/CSNP treatment in 3D model significantly reduced CD80, NFATc1, STAT6 and increased CD206 and periostin expression (p < 0.05). TNFα, MMP9 was downregulated and IL10, TGFß1, MMP2 upregulated with CSDEX/CSNP (p < 0.05). CSDEX/CSRB in animal study significantly reduced resorption, ankylosis, TRAP activity and osteocalcin expression and increased periostin (p<0.05). CSDEX demonstrated higher anti-inflammatory activity by downregulating TNFα, while CSNP upregulated TGFß1, periostin, and downregulated MMP9. The combination of matrix stabilization with CSRB with periostin upregulation and sustained releasing CSDEX showed potential for hampering root resorption and ankylosis in dental avulsion.

Engineered Immunomodulatory Nanoparticles Inhibit Root Resorption and Ankylosis.

INTRODUCTION: External root resorption following avulsion injury is a complex process wherein differentiation of macrophages (Mϕ) to multinucleated osteoclasts is temporally regulated by resident periodontal fibroblasts (PDLF). The current study aims to assess the effect of engineered bioactive chitosan nanoparticles (CSNP), sustained released dexamethasone conjugated CSNP (CS-DEX) and CSNP functionalized with photosensitizer Rose Bengal (CSRB) for application in root resorption using an in-vitro PDLF-Mϕ direct coculture model and in-vivo delayed reimplantation model. METHODS: PDLF-Mϕ direct coculture system was exposed to lipopolysaccharide (LPS), macrophage colony stimulating factor, receptor activator of nuclear factor kappa ß ligand with or without CSNP/CS-DEX for 7 days. Clastic differentiation was assessed by tartrate resistant acid phosphatase (TRAP) staining on day 7. On day 2 and 7, immunofluorescence analysis was conducted to assess the expression of Mϕ polarization markers (CD80, CD206), multinucleation markers (NFATc1, STAT6) in Mϕ and matricellular protein periostin in PDLF and cytokine profiling in cell culture supernatants. Delayed replantation model with extraoral air dry/LPS exposure for 1h followed by root surface treatment with CS-DEX/CSRB was used in Wistar rats. After 21 days, rats were euthanized for histologic and immunofluorescence analysis. Statistical analysis one-way ANOVA with Tukey's multiple comparisons was used to analyze the data (P < .05). RESULTS: CS-DEX significantly reduced TRAP+ multinucleated cells and CSNP treatment showed no TRAP+ cells. Immunofluorescence analysis showed that CSNP/CS-DEX reduced CD80, NFATc1 and STAT6 expression and increased periostin as expressed by fluorescence intensity. CSNP/CS-DEX significantly reduced TNFα, MMP9 and increased IL10, TGFß1. Osteoprotegerin was upregulated only by CSNP. Root surface treatment in delayed replantation model showed that CS-DEX and CSRB substantially reduced the degree of resorption and ankylosis. Further, CD80, CD206, and MMP2 expression in groups with root surface treatment with CS-DEX and CSRB was lower than airdry/LPS group and similar to healthy control and NFATc1, STAT6, and MMP9 expressions were lower than healthy control. CONCLUSION: The engineered nanosized immunomodulatory bioactive materials chitosan nanoparticles functionalized with photosensitizer and dexamethasone effectively reduced the clastic differentiation of Mϕ in in-vitro coculture and minimized the resorption and ankylosis in a delayed reimplantation model. These biomaterials have the potential to serve as root modification agents, promoting favorable healing outcomes in cases of dental avulsion.

SMARCB1 (INI1)-deficient sinonasal carcinoma manifesting as oral lesions: A report of two cases.

BACKGROUND: Sinonasal carcinomas represent a rare group of malignancies, accounting for less than 5% of all head and neck cancers and a worldwide incidence of less than 1 case per 100 000 inhabitants annually. Despite the restricted anatomical location, sinonasal carcinomas harbor some of the most histologically and molecularly diverse groups of tumors. SMARCB1 (INI1)-deficient sinonasal carcinomas are locally aggressive tumors commonly detected late, leading to devastating morbidity and mortality. CASE REPORT: We present two cases of SMARCB1-deficient sinonasal carcinoma involving the oral cavity and presenting as progressive radiolucent lesions with local swelling associated with maxillary dentition and alveolar bone. Both cases were initially considered odontogenic in origin and involved the destruction of the left anterior maxilla. CONCLUSION: Given the rarity and the variable presentation of these tumors, they pose a challenge for head and neck surgeons, dentists, and pathologists due to the potential overlapping features with odontogenic and non-odontogenic inflammatory and neoplastic lesions. These cases highlight the importance of a multidisciplinary team and include SMARCB1-deficient sinonasal carcinomas in the differential diagnosis of destructive lesions of the maxilla.

Effectiveness of coating acrylic resin dentures on preventing Candida adhesion.

PURPOSE: The aim of this study was to prevent the adhesion of C. albicans on acrylic resin dentures by modifying their surfaces. MATERIALS AND METHODS: Ninety acrylic resin plates were divided into three groups. Group I: conventionally processed acrylic resin plates. Group II: plates painted with 2-Octyl Cyanoacrylate adhesive. Group III: plates painted with Adper Single Bond Adhesive. All specimens were immersed separately in containers filled with artificial saliva that contained C. albicans and then incubated for 11 days at 37°C. Three methods of evaluation were used to count the adhered Candida: direct culture, slide count, and serial dilutions. RESULTS: C. albicans in 1/10, 1/10², and 1/10³ dilutions showed overgrowth in group I, while overgrowth was noted only with 1/10 dilution in group III. For group III, mean colony numbers of 123, 22, 3.4, and 0 were found for the 1/10², 1/10³, 1/104, and 1/105 dilutions, respectively. Regarding the slide counts, group I showed a mean fungal count of 166 compared to 40 for group III with 1/10 dilution, 21 compared to 9 with 1/10³ dilution, 8.6 compared to 0.7 with 1/10³ dilution, and 1.2 compared to 0 with 1/104 dilution. No plates in group II showed any candidal colonies regardless of the method of evaluation (0%). These differences were statistically significant (p < 0.0001). CONCLUSION: Coating the acrylic resin dentures with Adper Single Bond Adhesive was effective in reducing C. albicans adhesion to dentures, while coating with 2-Octyl Cyanoacrylate adhesive completely inhibited such adhesion.

Assessing Macrophage Polarization in Nanoparticle-Guided Wound Repair Using a Lipopolysaccharide Contaminated Intraosseous Model.

INTRODUCTION: Macrophages regulate the processes of inflammation and tissue regeneration/repair through their plasticity and phenotypes of different activation states. Previous studies have shown that disinfection of lipopolysaccharide (LPS)-contaminated dentin with photoactivated rose bengal-functionalized chitosan nanoparticles (CSRBnps) in vivo supported neotissue formation without signs of inflammation and root resorption. The aim of this study was to understand the mechanism underlying CSRBnp-guided attenuation of inflammation in LPS-contaminated dentin using macrophage polarization as an indicator of inflammation and repair. METHODS: To quantify the polarized macrophage populations, M1/M2-specific surface markers CD68, CD80, and CD206 and transcriptional factors signal transducer and activator of transcription (STAT) 1, STAT3, and STAT6 were determined using immunohistochemistry among previously obtained root specimens implanted into mandibles of guinea pigs for 4 weeks. In group 1, the canals were not inoculated; in group 2, the canals were inoculated with Pseudomonas aeruginosa LPS; in group 3, the canals were inoculated and disinfected with sodium hypochlorite; in group 4, the canals were inoculated and disinfected with sodium hypochlorite and calcium hydroxide; and in group 5, the canals were inoculated and disinfected with sodium hypochlorite, and CSRBnps (300 µg/mL) with photoactivation (λ = 540 nm, 40 J/cm2) were analyzed. RESULTS: An increased expression of M2-specific markers was observed in the group treated with CSRBnps compared with the groups treated with either conventional or no root canal disinfection. A statistically significant population of macrophages expressing both M1- and M2-specific markers was observed in all the tested groups. CONCLUSIONS: Disinfection of LPS-contaminated dentin with CSRBnps demonstrated M2-type polarization of macrophages, which corresponded to repair and neotissue formation.

Increase in detection of oral cancer and precursor lesions by dentists: Evidence from an oral and maxillofacial pathology service.

BACKGROUND: Dentists play an important role in the detection and diagnosis of oral diseases, including oral cancer and its precursor lesions. There are few comprehensive reviews in the recent literature that examine the scope and trends of oral disease diagnoses by dentists. METHODS: The authors analyzed all accessions to the Toronto Oral Pathology Service at the Faculty of Dentistry at the University of Toronto in Toronto, Ontario, Canada, from 2005 through 2015 using a custom-built database. They used these data to calculate the temporal trends in the diagnoses of oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). RESULTS: A total of 63,483 biopsy specimens were submitted primarily by dentists from 2005 through 2015. From these, 2,679 cases of OED and 828 OSCC were diagnosed. The authors' results show a 3.8-fold increase in the number of epithelial dysplasias and a 1.8-fold increase in mucosal carcinomas over the study period. The rate of increase of OED and OSCC was significantly higher than the rate of increase of total oral carcinomas diagnosed in the region, the population changes, and the number of dentists in the region. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Within the limitations of a study of a single large oral pathology biopsy service, the analysis of diagnoses shows that dentists are increasingly involved in the detection of oral mucosal carcinoma and precursor lesions. The dental community plays an important and increasing role in the detection of oral cancer and potentially malignant disorders. Increased awareness among oral health care and nonoral health care professionals may increase early detection of OSCC.

Inhibitory effect of zirconium oxide nanoparticles on Candida albicans adhesion to repaired polymethyl methacrylate denture bases and interim removable prostheses: a new approach for denture stomatitis prevention.

BACKGROUND: Despite drawbacks, cold-cured acrylic resin is still the most common material used in denture repair. Zirconia nanoparticles were among the reinforcements added to increase the strength of the resin. The effect on Candida due to the addition of zirconia nanoparticles to the resin has not been investigated. PURPOSE: The aim of this study was to evaluate the effect of zirconia nanoparticles added to cold-cured acrylic resin on Candida albicans adhesion. MATERIALS AND METHODS: A total of 120 acrylic resin specimens with dimensions measuring 22×10×2.5 mm3 were prepared and divided into two equal groups. One group (repair) comprised heat-polymerized specimens that were sectioned at the center and prepared to create a 2 mm repair area that was repaired with cold-cured resin reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. The second group contained intact cold-cured acrylic resin specimens reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. Specimens were incubated at 37°C in artificial saliva containing C. albicans, and the effect of zirconia nanoparticles on C. albicans was assessed using two methods: 1) a slide count method and 2) a direct culture test. Variations in the number of living Candida were observed in relation to the different concentrations of zirconia nanoparticles. Analysis of variance (ANOVA) and post hoc Tukey's tests were performed for data analysis. If the P-value was ≤0.05, then the difference was considered as statistically significant. RESULTS: It was found that C. albicans adhesion to repaired specimens was significantly decreased by the addition of zirconia nanoparticles (P<0.00001) in comparison with the control group. Intact cold-cured groups and groups repaired with cold-cured resin reinforced with 7.5% wt zirconia nanoparticles showed the lowest Candida count. Tukey's test showed a significant difference between the repaired group and the intact cold-cured group, while the later demonstrated a lower Candida count. CONCLUSION: The addition of zirconia nanoparticles to cold-cured acrylic resin is an effective method for reducing Candida adhesion to repaired polymethyl methacrylate (PMMA) denture bases and cold-cured removable prosthesis. CLINICAL SIGNIFICANCE: Based on the results of the current study, zirconia nanoparticles have an antifungal effect, which could be incorporated in the repair material for repairing denture bases and in PMMA removable prostheses as a possible approach for denture stomatitis prevention.

In Vitro Evaluation of the Inhibitory Activity of Thymoquinone in Combatting Candida albicans in Denture Stomatitis Prevention.

Candida albicans adhesion and proliferation on denture bases may lead to denture stomatitis, which is a common and recurrent problem in denture wearers. The goal of this study was to assess the inhibitory effect of thymoquinone incorporated in the polymethyl methacrylate denture base material against Candida albicans. Eighty acrylic resin specimens were fabricated and divided into eight groups (n = 10) according to thymoquinone concentrations of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 5% of acrylic powder. Two methods were used to evaluate the effect of thymoquinone on Candida albicans: the slide count and the serial dilution test. A multivariate analysis of variance (MANOVA) and the post-hoc Tukey's Honestly Significant Difference (HSD) test were performed to compare the difference of means between the observations taken at various intervals with baseline. The p value was statistically significant at ≤0.05. According to the slide count and the serial dilution test, the mean number of adhered Candida albicans in the control group was 5436.9 ± 266 and 4691.4 ± 176.8; however, this number dramatically decreased to 0 ± 0 and 32.4 ± 1.7 in group 8 (concentration 5%). These results suggest that the incorporation of thymoquinone into the acrylic resin denture base material might be effective in preventing Candida albicans adhesion.

Pulpal Responses to Direct Capping with Betamethasone/Gentamicin Cream and Mineral Trioxide Aggregate: Histologic and Micro-Computed Tomography Assessments.

INTRODUCTION: This clinical trial was conducted to evaluate the response of human dental pulp to direct capping with betamethasone/gentamicin (BG) cream and mineral trioxide aggregate (MTA). We hypothesized that the results of direct pulp capping with a topical BG combination would be similar to or better than those with MTA. METHODS: Thirty-six human first premolar teeth scheduled for orthodontic extraction were randomly divided into 4 groups: BG1 group (n = 9), BG cream with 2-week follow-up; BG2 group (n = 10), BG cream with 8-week follow-up; MTA1 group (n = 8), MTA with 2-week follow-up; and MTA2 group (n = 9), MTA with 8-week follow-up. Teeth were extracted and evaluated at respective time intervals. Micro-computed tomography scanning and histologic analyses were performed for all specimens. Pulp pathology (inflammation, pulp abscesses, and pulp necrosis) and reparative reaction (formation of dentin bridges) were recorded. RESULTS: Both BG cream and MTA resulted in significantly better pulpal responses at 8 weeks than at 2 weeks. Dentin bridge formation was significantly thicker in the MTA group at 8 weeks than in any other group (P < .05). Inflammation was of the acute type in all groups; no statistically significant differences in the distribution of inflammatory cells were found among the groups. Pulpal abscesses and/or necrosis were observed more often in teeth capped with BG than with MTA. CONCLUSIONS: Direct pulp capping with both BG cream and MTA was associated with dentin bridge formation. MTA resulted in a significantly better pulpal response, with less inflammation and a thicker dentin bridge at 8 weeks.

Antifungal Effect of Henna against Candida albicans Adhered to Acrylic Resin as a Possible Method for Prevention of Denture Stomatitis.

Denture stomatitis is a very common disease affecting the oral mucosa of denture wearers. The aim of this study was to measure the antifungal effect of henna against Candida albicans adhered to acrylic resin as a possible method for prevention of denture stomatitis. One-hundred-eighty acrylic plates were prepared of heat-cured acrylic denture resin. The specimens were divided into six groups of 30 samples each. The first group was only polymer and monomer following the conventional manufacturer instruction for processing complete dentures. The other five groups were processed by adding different concentration of Yamani henna powder (Harazi) to the polymer in a concentration of henna: polymer 1%, 2.5%, 5%, 7.5% and 10%, respectively. Samples were incubated in artificial saliva rich with Candida albicans at 37 °C, and the effect of henna on Candida albicans was evaluated in two different methods: semi-quantitative slide count and a culture-based quantitative assay (quantitative). Variation in the number of live Candida was observed with the increase in the concentration of Yamani henna powder. It was observed that the variation in live Candida, between control group and group B (concentration of Yamani henna powder was 1%), was statistically significant with a p-value of 0.0001. Similarly, variations in live Candida were significant, when the concentration of powder was 7.5% or 10% in contrast with control group and p-values were 0.0001 and 0.001 respectively. Adding henna to acrylic resin denture could be effective in controlling Candida albicans proliferation on the denture surface; however, its effects on the physical properties of acrylic resin denture need further studies.

Prevalence of denture-related oral lesions among patients attending College of Dentistry, University of Dammam: A clinico-pathological study.

BACKGROUND: Heterogeneous groups of oral lesions are likely to develop among denture wearers. The objectives of this study were to determine the exact prevalence of oral lesions among denture wearers attending the clinics of the College of Dentistry, University of Dammam. MATERIALS AND METHODS: All denture wearers attending the dental clinics in the period between January 2012 and April 2013 were included in this study. Of the total 210 patients, 166 (79%) were males and 44 (21%) were females. Comprehensive oral examination was performed for all patients. Any denture-induced lesion was biopsied. Data collected were analyzed using SPSS program. RESULTS: Oral lesions were found in 20.5% of the cases under study (43 out of the total 210 denture wearers). Denture-induced fibrous hyperplasia was the most common type of lesion detected (41.9%). A significant correlation (P = 0.004) was found between the type of denture and oral lesions in this study. CONCLUSION: The prevalence of denture-induced oral lesions was found to differ significantly from that reported in other studies. The diversity of these lesions among different studies depends on the quality and materials of dentures delivered, the techniques used, and the methods of patients' instructions adopted.

Qat habit in Yemen society: a causative factor for oral periodontal diseases.

The effect of a common habit among Yemeni population on the periodontal status was investigated. This cross-sectional study was done on 2500 Yemenis with mean age 27.01 years (1818 males and 682 females). Among these 1528 were qat chewers and 972 were non-chewers. Detailed questionnaire and pre-designed scoring system for the periodontal status were employed for each case. Study results indicated that out of 972 non-chewers 116(12%) had periodontal pocketing and 18 (1.9%) cases had gingival recession. On the other hand, out of 1528 chewers, 468 (31.8%) had periodontal pockets and 98 (6.4%) with gum bleeding, p<0.05. These effects were found to increase with increased frequency and duration of chewing. It was concluded that habit of qat can cause damage to the periodontal ligament as pocketing and gum recession.