Transient Receptor Potential Channel Vanilloid 1 Contributes to Facial Mechanical Hypersensitivity in a Mouse Model of Atopic Asthma.

Sensitive skin, a common pathophysiological feature of allergic diseases, is defined as an unpleasant sensation in response to stimuli that normally should not provoke such sensations. However, the relationship between allergic inflammation and hypersensitive skin in the trigeminal system remains to be elucidated. To explore whether bronchial allergic inflammation affects facial skin and primary sensory neurons, we used an ovalbumin (OVA)-induced asthma mouse model. Significant mechanical hypersensitivity was observed in the facial skin of mice with pulmonary inflammation induced by OVA sensitization compared to mice treated with adjuvant or vehicle as controls. The skin of OVA-treated mice showed an increased number of nerve fibers, especially rich intraepithelial nerves, compared to controls. Transient receptor potential channel vanilloid 1 (TRPV1)-immunoreactive nerves were enriched in the skin of OVA-treated mice. Moreover, epithelial TRPV1 expression was higher in OVA-treated mice than in controls. Trigeminal ganglia of OVA-treated mice displayed larger numbers of activated microglia/macrophages and satellite glia. In addition, more TRPV1 immunoreactive neurons were found in the trigeminal ganglia of OVA-treated mice than in controls. Mechanical hypersensitivity was suppressed in OVA-treated Trpv1-deficient mice, while topical skin application of a TRPV1 antagonist before behavioral testing reduced the reaction induced by mechanical stimulation. Our findings reveal that mice with allergic inflammation of the bronchi had mechanical hypersensitivity in the facial skin that may have resulted from TRPV1-mediated neuronal plasticity and glial activation in the trigeminal ganglion.

Enhanced junctional epithelial permeability in TRPV4-deficient mice.

BACKGROUND AND OBJECTIVE: As the interface between the oral cavity and the teeth, the junctional epithelial barrier is critical for gingival defense. The junctional epithelium is subject to mechanical stresses from biting force or external insults such as bacterial attacks, but little is known about the effects of mechanical stimuli on epithelial functions. Transient receptor potential vanilloid 4 (TRPV4) functions as a mechanosensitive nonselective cation channel. In the present study, based on marked expression of TRPV4 in the mouse junctional epithelium, we aimed to clarify the putative links between TRPV4 and junctional complexes in the junctional epithelium. METHODS AND RESULTS: Histological observations revealed that the junctional epithelium in TRPV4-deficient (TRPV4-/- ) mice had wider intercellular spaces than that in wild-type (TRPV4+/+ ) mice. Exogenous tracer penetration in the junctional epithelium was greater in TRPV4-/- mice than in TRPV4+/+ mice, and immunoreactivity for adherens junction proteins was suppressed in TRPV4-/- mice compared with TRPV4+/+ mice. Analysis of a mouse periodontitis model showed greater bone volume loss in TRPV4-/- mice compared with TRPV4+/+ mice, indicating that an epithelial barrier deficiency in TRPV4-/- mice may be associated with periodontal complications. CONCLUSION: The present findings identify a crucial role for TRPV4 in the formation of adherens junctions in the junctional epithelium, which could regulate its permeability. TRPV4 may be a candidate pharmacological target to combat periodontal diseases.

Clinical Effect of Virtual Reality to Relieve Anxiety During Impacted Mandibular Third Molar Extraction Under Local Anesthesia.

PURPOSE: Many patients undergoing dental treatment have experienced pain associated with the treatment and become anxious and/or fearful of treatment. Anxiety and fear have conventionally been managed with the use of inhalation anesthesia or tranquilizers. However, their physical effects must also be considered, and they will not be suitable for all patients. The purpose of the present study was to assess the clinical effect of virtual reality (VR) to relieve anxiety during impacted mandibular third molar extraction under local anesthesia. MATERIALS AND METHODS: We used VR to alleviate anxiety concerning surgical treatment for 51 patients undergoing impacted mandibular third molar extraction under local anesthesia. Fear and anxiety before and after treatment were evaluated by a questionnaire that included a visual analog scale (VAS). The post-treatment questionnaire asked patients to evaluate their satisfaction on a 5-level Likert scale. Heart rate variability (HRV) was also analyzed in the VR group using acceleration plethysmography. RESULTS: Anxiety had decreased among the patients who had used VR (VR group), with a difference of -13.3 ± 28.7 mm in anxiety measured using a VAS before and during treatment. In contrast, it had increased by 4.0 ± 22.3 mm in the 49 patients who had not used VR. Furthermore, the post-treatment questionnaire administered to the VR group revealed that 92% had reported that their anxiety had decreased. Objective evaluation by HRV measurement also showed a sympathetic nerve-predominant state before treatment. However, with VR use during treatment, parasympathetic nervous activity was predominant, with a stable balance between the 2. No patient showed symptoms suggestive of cybersickness. CONCLUSIONS: These results have shown that the use of VR could be valuable during dental treatment, especially extractions and surgical treatment.

The thermosensitive TRPV3 channel contributes to rapid wound healing in oral epithelia.

The oral cavity provides an entrance to the alimentary tract to serve as a protective barrier against harmful environmental stimuli. The oral mucosa is susceptible to injury because of its location; nonetheless, it has faster wound healing than the skin and less scar formation. However, the molecular pathways regulating this wound healing are unclear. Here, we show that transient receptor potential vanilloid 3 (TRPV3), a thermosensitive Ca(2+)-permeable channel, is more highly expressed in murine oral epithelia than in the skin by quantitative RT-PCR. We found that temperatures above 33°C activated TRPV3 and promoted oral epithelial cell proliferation. The proliferation rate in the oral epithelia of TRPV3 knockout (TRPV3KO) mice was less than that of wild-type (WT) mice. We investigated the contribution of TRPV3 to wound healing using a molar tooth extraction model and found that oral wound closure was delayed in TRPV3KO mice compared with that in WT mice. TRPV3 mRNA was up-regulated in wounded tissues, suggesting that TRPV3 may contribute to oral wound repair. We identified TRPV3 as an essential receptor in heat-induced oral epithelia proliferation and wound healing. Our findings suggest that TRPV3 activation could be a potential therapeutic target for wound healing in skin and oral mucosa.

Erythropoietin receptor signal is crucial for periodontal ligament stem cell-based tissue reconstruction in periodontal disease.

Alveolar bone loss caused by periodontal disease eventually leads to tooth loss. Periodontal ligament stem cells (PDLSCs) are the tissue-specific cells for maintaining and repairing the periodontal ligament, cementum, and alveolar bone. Here, we investigated the role of erythropoietin receptor (EPOR), which regulates the microenvironment-modulating function of mesenchymal stem cells, in PDLSC-based periodontal therapy. We isolated PDLSCs from patients with chronic periodontal disease and healthy donors, referred to as PD-PDLSCs and Cont-PDLSCs, respectively. PD-PDLSCs exhibited reduced potency of periodontal tissue regeneration and lower expression of EPOR compared to Cont-PDLSCs. EPOR-silencing suppressed the potency of Cont-PDLSCs mimicking PD-PDLSCs, whereas EPO-mediated EPOR activation rejuvenated the reduced potency of PD-PDLSCs. Furthermore, we locally transplanted EPOR-silenced and EPOR-activated PDLSCs into the gingiva around the teeth of ligament-induced periodontitis model mice and demonstrated that EPOR in PDLSCs participated in the regeneration of the periodontal ligament, cementum, and alveolar bone in the ligated teeth. The EPOR-mediated paracrine function of PDLSCs maintains periodontal immune suppression and bone metabolic balance via osteoclasts and osteoblasts in the periodontitis model mice. Taken together, these results suggest that EPOR signaling is crucial for PDLSC-based periodontal regeneration and paves the way for the development of novel options for periodontal therapy.

Effectiveness of perioperative oral hygiene management using a cetylpyridinium chloride-, dipotassium glycyrrhizinate, and tranexamic acid-based mouthwash as an adjunct to mechanical oral hygiene in patients with maxillomandibular fixation: A randomized controlled clinical trial.

OBJECTIVES: Maxillomandibular fixation requires the jawbones to remain static. Mechanical cleaning is also carried out by brushing or with a water flosser to maintain the oral cavity in a hygienic state, but this cannot be considered sufficient. Mouthwashes are used as a substitute for mechanical cleaning or in a supplementary role after such cleaning. The aim is to evaluate the effectiveness of HABITPRO mouthwash, which contains cetylpyridinium chloride, dipotassium glycyrrhizinate, and tranexamic acid in the specific environment created by maxillomandibular fixation used as an adjunct to mechanical cleaning. MATERIAL AND METHODS: A total of 55 patients who had undergone maxillomandibular fixation were randomly allocated to either a HABITPRO group (n = 29) or a placebo group (n = 26). To investigate their oral hygiene status, their plaque control record (PCR) was reviewed, and the caries-related bacterial counts, pH, acid buffering capacity, white blood cell count, and ammonia in saliva were measured immediately before maxillomandibular fixation, on Day 10 of fixation, and immediately after fixation was released. RESULTS: After approximately 2-3 weeks of mouthwash use, the PCR index also increased significantly in the placebo group compared with baseline, whereas it remained almost steady in the HABITPRO group. Additionally, salivary ammonia levels decreased significantly in the HABITPRO group compared to that of the placebo group. CONCLUSIONS: Even with maxillomandibular fixation, continued gargling with HABITPRO mouthwash in the perioperative period as an adjunct to mechanical cleaning can help maintain better oral hygiene and reduce bacterial counts.

Clinical effects of different virtual reality presentation content on anxiety and pain: a randomized controlled trial.

Many patients are frightened of or anxious about dental treatment. We have recently reported our use of virtual reality (VR) to alleviate the fear and anxiety experienced during oral surgical procedures However, the effectiveness of VR in alleviating anxiety varies greatly between individuals. We therefore investigated whether the content of the VR presentation made any difference to its effect in alleviating anxiety, and whether it had any analgesic effect. The study subjects experienced one of two different types of VR presentation and were asked to complete a questionnaire about any changes in their anxiety during the procedure, including a visual analog scale (VAS) score. As an objective evaluation, changes in pain threshold during the VR presentation were investigated using PainVision. For those patients who experienced a presentation showing a natural landscape, the change in VAS score was - 13.3 ± 28.7 mm, whereas for those who experienced a presentation showing a video game the change was - 22.2 ± 32.1 mm, an even greater reduction. In a pain questionnaire completed by individuals who had experienced the video game presentations, approximately 70% reported that their pain had diminished. An objective evaluation of pain threshold also showed that the pain threshold of individuals increased by around 3% while experiencing the natural landscape VR presentation, but that while experiencing the video game presentation, it increased significantly by around 15% compared with baseline. These results show that the content of the presentation affected not only the rate of decrease in anxiety, but also the pain threshold.

Case report: Open bite as an extrapyramidal side effect with aripiprazole, a dopamine partial agonist.

Long-term, fixed-point posttreatment observation of orthodontically treated patients provided us with the opportunity to capture the onset, development, and improvement of open bite, a type of malocclusion. Based on the chronological sequence of events, i.e., a tendency for open bite to worsen with increasing aripiprazole dosage and to improve with decreasing dosage, it was inferred that the onset of malocclusion was caused by extrapyramidal symptoms related to aripiprazole dosage. Physicians should be aware of this side effect when prescribing aripiprazole to children and adolescents. Careful consideration of medication history is necessary when dentists treat open bite in children and adolescents.

Protocol for a multicentre, prospective observational study of elective neck dissection for clinically node-negative oral tongue squamous cell carcinoma (END-TC study).

INTRODUCTION: In early-stage oral tongue squamous cell carcinoma (OTSCC), elective neck dissection (END) is recommended when occult lymph node metastasis is suspected; however, there is no unanimous consensus on the risks and benefits of END in such cases. The management of clinically node-negative (cN0) OTSCC remains controversial. This study, therefore, aimed to evaluate the efficacy of END and its impact on the quality of life (QoL) of patients with cN0 OTSCC. METHODS AND ANALYSIS: This is a prospective, multicentre, nonrandomised observational study. The choice of whether to perform END at the same time as resection of the primary tumour is based on institutional policy and patient preference. The primary endpoint of this study is 3-year overall survival. The secondary endpoints are 3-year disease-specific survival, 3-year relapse-free survival and the impact on patient QoL. Propensity score-matching analysis will be performed to reduce selection bias. ETHICS AND DISSEMINATION: This study was approved by the Clinical Research Review Board of the Nagasaki University. The protocol of this study was registered at the University Hospital Medical Information Network Clinical Trials Registry. The datasets generated during the current study will be available from the corresponding author on reasonable request. The results will be disseminated internationally, through scientific and professional conferences and in peer-reviewed medical journals. TRIAL REGISTRATION NUMBER: UMIN000027875.

Clinical evaluation of steroid ointment for the treatment of mucoceles.

OBJECTIVE: We examined whether steroid ointment (0.1% dexamethasone) is an effective treatment for mucoceles. STUDY DESIGN: Using a retrospective cohort study design, a statistical study was conducted of 91 patients diagnosed with mucoceles at the Department of Dental and Oral Surgery, Saga University Hospital, Saga, Japan, between January 2006 and December 2016. The patients' age and sex; shape, size, and site of the lesion; duration; and treatment response rate were evaluated. RESULTS: The most frequent site of mucoceles was the lower labial mucosa, and several were <10 mm in size. The age of onset was often <20 years, with no sex-based differences. The treatment response rate was 65.8% for steroid ointment and 100% for surgical removal. In the subgroup analysis according to each clinical factor, some subgroups showed statistically nonsignificant differences compared with the surgery group. Among them, the older age and short disease duration subgroups showed small risk differences, suggesting that application of ointment may lead to a response in these subgroups. CONCLUSIONS: Although its response rate was lower than that of surgical removal, topical steroid application is a noninvasive and useful treatment method that can be used for patients in whom surgical treatment is infeasible.

Impaired Junctions and Invaded Macrophages in Oral Epithelia With Oral Pain.

Recurrent or chronic oral pain is a great burden for patients. Recently, the links between epithelial barrier loss and disease were extended to include initiation and propagation. To explore the effects of pathohistological changes in oral epithelia on pain, we utilized labial mucosa samples in diagnostic labial gland biopsies from patients with suspected Sjögren's syndrome (SS), because they frequently experience pain and discomfort. In most labial mucosa samples from patients diagnosed with SS, disseminated epithelial cellular edema was prevalent as ballooning degeneration. The disrupted epithelia contained larger numbers of infiltrating macrophages in patients with oral pain than in patients without pain. Immunohistochemistry revealed that edematous areas were distinct from normal areas, with disarranged cell-cell adhesion molecules (filamentous actin, E-cadherin, ß-catenin). Furthermore, edematous areas were devoid of immunostaining for transient receptor potential channel vanilloid 4 (TRPV4), a key molecule in adherens junctions. In an investigation on whether impaired TRPV4 affect cell-cell adhesion, calcium stimulation induced intimate cell-cell contacts among oral epithelial cells from wild-type mice, while intercellular spaces were apparent in cells from TRPV4-knockout mice. The present findings highlight the relationship between macrophages and epithelia in oral pain processing, and identify TRPV4-mediated cell-cell contacts as a possible target for pain treatment.

The oral mucosal membrane and transient receptor potential channels.

The oral cavity is the first line of defense, sensation, and secretion of the alimentary canal. Oral perception contributes to the enjoyment of food and beverages and to avoiding consumption of poisonous or harmful substances. Oral sensation is served by somatosensory nervous systems distributed to the oral membrane. Recent studies reported that oral epithelial cells may transduce temperature and touch through membranous sensors, which comprise ion channels with multimodal properties, and nerves. Here, we describe the possible role of oral epithelial cells in oral perception.

Interferon-gamma improves impaired dentinogenic and immunosuppressive functions of irreversible pulpitis-derived human dental pulp stem cells.

Clinically, irreversible pulpitis is treated by the complete removal of pulp tissue followed by replacement with artificial materials. There is considered to be a high potential for autologous transplantation of human dental pulp stem cells (DPSCs) in endodontic treatment. The usefulness of DPSCs isolated from healthy teeth is limited. However, DPSCs isolated from diseased teeth with irreversible pulpitis (IP-DPSCs) are considered to be suitable for dentin/pulp regeneration. In this study, we examined the stem cell potency of IP-DPSCs. In comparison with healthy DPSCs, IP-DPSCs expressed lower colony-forming capacity, population-doubling rate, cell proliferation, multipotency, in vivo dentin regeneration, and immunosuppressive activity, suggesting that intact IP-DPSCs may be inadequate for dentin/pulp regeneration. Therefore, we attempted to improve the impaired in vivo dentin regeneration and in vitro immunosuppressive functions of IP-DPSCs to enable dentin/pulp regeneration. Interferon gamma (IFN-γ) treatment enhanced in vivo dentin regeneration and in vitro T cell suppression of IP-DPSCs, whereas treatment with tumor necrosis factor alpha did not. Therefore, these findings suggest that IFN-γ may be a feasible modulator to improve the functions of impaired IP-DPSCs, suggesting that autologous transplantation of IFN-γ-accelerated IP-DPSCs might be a promising new therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment.

Transplantation of mesenchymal stem cells ameliorates secondary osteoporosis through interleukin-17-impaired functions of recipient bone marrow mesenchymal stem cells in MRL/lpr mice.

INTRODUCTION: Secondary osteoporosis is common in systemic lupus erythematosus and leads to a reduction in quality of life due to fragility fractures, even in patients with improvement of the primary disorder. Systemic transplantation of mesenchymal stem cells could ameliorate bone loss and autoimmune disorders in a MRL/lpr mouse systemic lupus erythematosus model, but the detailed therapeutic mechanism of bone regeneration is not fully understood. In this study, we transplanted human bone marrow mesenchymal stem cells (BMMSCs) and stem cells from exfoliated deciduous teeth (SHED) into MRL/lpr mice and explored their therapeutic mechanisms in secondary osteoporotic disorders of the systemic lupus erythematosus model mice. METHODS: The effects of systemic human mesenchymal stem cell transplantation on bone loss of MRL/lpr mice were analyzed in vivo and ex vivo. After systemic human mesenchymal stem cell transplantation, recipient BMMSC functions of MRL/lpr mice were assessed for aspects of stemness, osteogenesis and osteoclastogenesis, and a series of co-culture experiments under osteogenic or osteoclastogenic inductions were performed to examine the efficacy of interleukin (IL)-17-impaired recipient BMMSCs in the bone marrow of MRL/lpr mice. RESULTS: Systemic transplantation of human BMMSCs and SHED recovered the reduction in bone density and structure in MRL/lpr mice. To explore the mechanism, we found that impaired recipient BMMSCs mediated the negative bone metabolic turnover by enhanced osteoclastogenesis and suppressed osteoblastogenesis in secondary osteoporosis of MRL/lpr mice. Moreover, IL-17-dependent hyperimmune conditions in the recipient bone marrow of MRL/lpr mice damaged recipient BMMSCs to suppress osteoblast capacity and accelerate osteoclast induction. To overcome the abnormal bone metabolism, systemic transplantation of human BMMSCs and SHED into MRL/lpr mice improved the functionally impaired recipient BMMSCs through IL-17 suppression in the recipient bone marrow and then maintained a regular positive bone metabolism via the balance of osteoblasts and osteoclasts. CONCLUSIONS: These findings indicate that IL-17 and recipient BMMSCs might be a therapeutic target for secondary osteoporosis in systemic lupus erythematosus.

Milk basic protein supplementation enhances fracture healing in mice.

OBJECTIVES: There is an unmet need for agents that can stimulate bone healing. The goal of this study was to evaluate the effects of basic proteins from milk whey (milk basic protein [MBP]) on fracture healing in mice. METHODS: Closed tibial transverse fractures were generated in 6-wk-old male C3 H/HeJ mice given either tap water or MBP-supplemented water for 3, 7, 14, 28, and 56 d after fracture generation. The tibial tissues were analyzed by radiography, µCT, and a three-point bending test. The expression levels of genes associated with bone metabolism were analyzed by real-time reverse transcription-polymerase chain reaction. RESULTS: Quantitative µCT analysis showed that MBP-treated fractured tibiae had a larger hard callus in the sectional area and a larger volume compared with fractured tibiae without MBP treatment. The expression levels of genes associated with chondrogenesis and osteogenesis showed greater increases in fractured tibiae with MBP treatment. Significant increases in the callus mechanical properties were found in MBP-treated tibiae. CONCLUSIONS: MBP supplementation has the potential to improve fracture healing and bone strength in mouse tibiae. MBP could be a potential safe, low-cost, and easily administered nutritional element to prevent secondary fractures in patients with bone fractures.

In vivo hepatogenic capacity and therapeutic potential of stem cells from human exfoliated deciduous teeth in liver fibrosis in mice.

INTRODUCTION: Liver transplantation is a gold standard treatment for intractable liver diseases. Because of the shortage of donor organs, alternative therapies have been required. Due to their potential to differentiate into a variety of mature cells, stem cells are considered feasible cell sources for liver regeneration. Stem cells from human exfoliated deciduous teeth (SHED) exhibit hepatogenic capability in vitro. In this study, we investigated their in vivo capabilities of homing and hepatocyte differentiation and therapeutic efficacy for liver disorders in carbon tetrachloride (CCl4)-induced liver fibrosis model mice. METHODS: We transplanted SHED into CCl4-induced liver fibrosis model mice through the spleen, and analyzed the in vivo homing and therapeutic effects by optical, biochemical, histological, immunological and molecular biological assays. We then sorted human leukocyte antigen-ABC (HLA-ABC)-positive cells from primary CCl4-damaged recipient livers, and analyzed their fusogenicity and hepatic characteristics by flow cytometric, genomic DNA, hepatocyte-specific gene assays. Furthermore, we examined the treatment effects of HLA-positive cells to a hepatic dysfunction by a secondary transplantation into CCl4-treated mice. RESULTS: Transplanted SHED homed to recipient livers, and expressed HLA-ABC, human hepatocyte specific antigen hepatocyte paraffin 1 and human albumin. SHED transplantation markedly recovered liver dysfunction and led to anti-fibrotic and anti-inflammatory effects in the recipient livers. SHED-derived HLA-ABC-positive cells that were sorted from the primary recipient liver tissues with CCl4 damage did not fuse with the host mouse liver cells. Sorted HLA-positive cells not only expressed human hepatocyte-specific genes including albumin, cytochrome P450 1A1, fumarylacetoacetase, tyrosine aminotransferase, uridine 5'-diphospho-glucuronosyltransferase, transferrin and transthyretin, but also secreted human albumin, urea and blood urea nitrogen. Furthermore, SHED-derived HLA-ABC-positive cells were secondary transplanted into CCl4-treated mice. The donor cells homed into secondary recipient livers, and expressed hepatocyte paraffin 1 and human albumin, as well as HLA-ABC. The secondary transplantation recovered a liver dysfunction in secondary recipients. CONCLUSIONS: This study indicates that transplanted SHED improve hepatic dysfunction and directly transform into hepatocytes without cell fusion in CCl4-treated mice, suggesting that SHED may provide a feasible cell source for liver regeneration.