Antimicrobial Effect of Extracellular Vesicles Derived From Human Oral Mucosal Epithelial Cells on Candida albicans

Candida albicans (C. albicans) is a commensal microorganism that colonizes the mucosal surfaces of healthy individuals. Changes in the host or environment can lead to overgrowth of C. albicans and infection of the host. Extracellular vesicles (EVs) are released by almost all cell types and play an increasingly recognized role in fighting microbial infection. The aim of the present study was to assess whether EVs derived from human oral mucosal epithelial (Leuk-1) cells can suppress the growth and invasion of C. albicans. The in vitro efficacy of Leuk-1-EVs against C. albicans was assessed by optical microscopy, laser scanning confocal microscopy, scanning electron microscopy, and transmission electron microscopy. The germ tube formation rate, the percentage of hyphae and the microcolony optical density were also used to analyze the growth of C. albicans in a coculture model with Leuk-1 cells and EVs or after inhibition of the secretion of EVs. A mouse model of oral candidiasis was established and submucosal injection of Leuk-1-EVs in the tongue was performed. Macroscopic observation, H&E staining, PAS staining, and scanning electron microscopy were used to assess antifungal effects of Leuk-1-EVs in vivo. The in vitro results showed that the growth of C. albicans was inhibited and that the morphology and ultrastructure were changed following Leuk-1-EVs treatment. The in vivo results exhibited that white lesions of the tongue, C. albicans infection, and oral mucosal inflammation of the infected mice were significantly alleviated after Leuk-1-EVs treatment. We thus reveal an antifungal capability of EVs derived from oral epithelial cells against C. albicans that is mediated by direct damage effects and potential synergy between EVs and human oral mucosal epithelial cells. This finding offers an intriguing, previously overlooked method of antifungal defense against C. albicans.

Smoking increases oral mucosa susceptibility to Candida albicans infection via the Nrf2 pathway: In vitro and animal studies

Smoking and Candidaalbicans (C. albicans) infection are risk factors for many oral diseases. Several studies have reported a close relationship between smoking and the occurrence of C. albicans infection. However, the exact underlying mechanism of this relationship remains unclear. We established a rat infection model and a C. albicans‐Leuk1 epithelial cell co‐culture model with and without smoke exposure to investigate the mechanism by which smoking contributes to C. albicans infection. Oral mucosa samples from healthy individuals and patients with oral leucoplakia were also analysed according to their smoking status. Our results indicated that smoking induced oxidative stress and redox dysfunction in the oral mucosa. Smoking‐induced Nrf2 negatively regulated the NLRP3 inflammasome, impaired the oral mucosal defence response and increased the oral mucosa susceptibility to C. albicans. The results suggest that the Nrf2 pathway could be involved in the pathogenesis of oral diseases by mediating an antioxidative response to cigarette smoke exposure and suppressing host immunity against C. albicans.

Relationship between dietary factors and recurrent aphthous stomatitis in China: a cross-sectional study

Objective

Recurrent aphthous stomatitis (RAS), a common oral mucosal disorder characterized by chronic, inflammatory, and ovoid ulcers, has a complex etiology. The purpose of the study was to investigate the specific dietary factors influencing the prevalence of RAS.

Methods

A total of 754 participants aged 18 to 59 years were enrolled in this descriptive cross-sectional study. An anonymous questionnaire was adopted to investigate the distribution of RAS, dietary factors, self-reported trigger factors, and therapeutic methods.

Results

Among all participants, the prevalence rate of RAS was 21.4%. Univariable analysis showed that fruit, dairy products, vegetables, and water, but not fried foods, fermented foods, spicy foods, and eggs, were preventive factors against RAS. After adjusting for age and sex, multivariable regression analysis suggested that fruit (adjusted odds ratio [aOR] = 0.430, 95% confidence interval [CI] = 0.218–0.847) and water (aOR = 0.294, 95% CI = 0.119–0.726) were protective factors against RAS.

Conclusion

This study found that the consumption of fruit and water was negatively associated with RAS. These results imply a potential adjunctive and complementary role of food in RAS treatment and some feasible means of RAS prevention.

Extracellular vesicles as potential biomarkers and therapeutic approaches in autoimmune diseases

Extracellular vesicles are heterogeneous populations of naturally occurring secreted small vesicles. EVs function as signaling platforms to facilitate intracellular communication, which indicates the physiological or pathophysiological conditions of cells or tissues. Considering that EVs can be isolated from most body fluids and that molecular constituents could be reprogrammed according to the physiological status of the secreting cells, EVs are regarded as novel diagnostic and prognostic biomarkers for many diseases. The ability to protect encapsulated molecules from degradation in body fluids suggests the potential of EVs as biological medicines or drug delivery systems. This article focuses on the EV-associated biomarkers and therapeutic approaches in autoimmune diseases.

From SARS to COVID-19: What lessons have we learned?

After the outbreak of severe acute respiratory syndrome (SARS) in November 2002, coronaviruses (CoVs) received worldwide attention. On December 1, 2019, the first case of coronavirus disease 2019 (COVID-19), caused by a novel coronavirus (SARS-CoV-2), was reported in Wuhan, China, and CoVs returned to public view. On January 30, 2020, the World Health Organization (WHO) declared that the COVID-19 epidemic is a public health emergency of international concern (PHEIC), and on March 11, 2020, the WHO classified COVID-19 as a pandemic disease. As of July 31, 2020, COVID-19 has affected 216 countries and regions, with 17,064,064 confirmed cases and 668,073 deaths, and the number of new cases has been increasing daily. Additionally, on March 19, 2020, there were no new confirmed cases in China, providing hope and valuable experience for the international community. In this review, we systematically compare COVID-19 and SARS in terms of epidemiology, pathogenesis and clinical characteristics and discuss the current treatment approaches, scientific advancements and Chinese experience in fighting the epidemic to combat the novel coronavirus pandemic. We also discuss the lessons that we have learned from COVID-19 and SARS.

Effects of Candida albicans infection on defense effector secretion by human oral mucosal epithelial cells

OBJECTIVE

The aim of this study was to investigate the effects of Candida albicans on the production of defense effector molecules by human oral mucosal epithelial cells in vitro.

DESIGN

Immortalized human oral mucosal epithelial (Leuk-1) cells and C. albicans strain 5314 were cocultured at different cell-to-C. albicans ratios. The viability of Leuk-1 cells was determined by MTT and RTCA measurements. The secretory levels of multiple defense effector molecules were determined by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our results indicated that C. albicans significantly decreased the secretion of IgG, cystatin C, lactoferrin, and TGF-β1 in a dose-dependent manner and remarkably reduced the production of IgA independent of the cell-to-C. albicans ratio. However, C. albicans clearly enhanced the secretion of IgM, galectin-3, P-selectin, granzyme B and perforin.

CONCLUSION

These results suggest that C. albicans may exert a regulatory role in the defense response of oral mucosal epithelial cells by altering secretory levels of defense effector molecules.

Mystery behind labial and oral melanotic macules: Clinical, dermoscopic and pathological aspects of Laugier-Hunziker syndrome

Labial and oral melanotic macules are commonly encountered in a broad range of conditions ranging from physiologic pigmentation to a sign of an underlying life-threatening disease. Although Laugier-Hunziker syndrome (LHS) shares some features of labial and oral pigmentation with a variety of conditions, it is a benign and acquired condition, frequently associated with longitudinal melanonychia. Herein, the demographic, clinical, dermoscopic, and pathological aspects of LHS were reviewed comprehensively. The important differential diagnoses of mucocutaneous and nail pigmentation are provided. An accurate diagnosis is crucial to design a reasonable medical strategy, including management options, malignant transformation surveillance, and psychological support. It is important that clinicians conduct long-term follow-up and surveillance due to the potential risks of malignant transformation and local severe complications in some conditions.

Frequencies of abnormal humoral and cellular immune component levels in peripheral blood of patients with recurrent aphthous ulceration

BACKGROUND/PURPOSE

Recurrent aphthous ulceration (RAU) has an incidence of approximately 20% in general population. However, its exact cause remains unknown. Increasing evidence suggests that immunologic mechanisms may play crucial roles in the etiology of this disease.

MATERIALS AND METHODS

The peripheral blood samples were obtained from 85 patients with RAU during acute phase and 87 healthy controls. The serum levels of IgG, IgA, IgM, C3 and C4 were measured by immunoturbidimetry. In addition, the serum IgE levels were measured by electro-chemiluminescence immunoassay. Furthermore, the percentages of B, T, CD4+ T, CD8+ T lymphocytes and natural killer (NK) cells in peripheral blood were determined by flow cytometry.

RESULTS

Our findings showed that the serum IgG, IgA, IgE, C3 and C4 levels of RAU patients were significantly higher than those of healthy controls. The percentages of CD4+ T cells and B cells in peripheral blood of RAU patients were significantly decreased, whereas the percentages of CD8+ T cells and NK cells of RAU patients were remarkably increased. Our results indicated that the IgG level was elevated in 18 patients (21.2%) and that the IgE level was increased in 21 patients (24.7%). Our results also showed that the frequency of abnormal IgG or IgE levels were significantly correlated with that of abnormal CD8+ T cell percentage in RAU patients.

CONCLUSION

The levels of both humoral and cellular immune components could be altered in RAU. The relationship between humoral and cellular immune may be potentially important immunologic aspects involved in the pathogenesis of RAU.

Laugier-Hunziker syndrome: A case report

Laugier-Hunziker syndrome (LHS) is a rare, benign, acquired pigmentary condition mainly affecting lips, oral mucosa and acral area, frequently associated with longitudinal melanonychia. Herein, we reported a 45-year-old female case with LHS. The clinical, dermoscopic, histopathologic features of LHS were reviewed and the important differential diagnosis was discussed.