Oral lichen planus: a microbiologist point of view

Impact of exosomes in oral lichen planus: A review with insights into pathogenesis and biomarkers

Oral Lichen Planus (OLP) presents a significant challenge in diagnosis due to its varied clinical manifestations and the absence of specific biomarkers. Timely and accurate diagnosis is crucial, particularly given its association with oral squamous cell carcinoma (OSCC). This review aims to explore the potential role of exosomes, small extracellular vesicles, in the pathogenesis of OLP and their utility as diagnostic biomarkers. Exosomes facilitate the exchange of information between cells and modulate immune responses by carrying various bioactive molecules such as proteins, lipids, and nucleic acids. In the context of OLP, exosomes derived from affected tissues or immune cells are thought to contribute to disease progression by mediating the transfer of pro-inflammatory molecules, including cytokines like interleukin-6 and tumour necrosis factor-alpha and chemokines such as CCL2, CCL5 and microRNAs such as miR-155, miR-146a, miR-21, and miR-34a, etc. Additionally, the distinct molecular contents of exosomes derived from OLP lesions may accurately represent the pathological changes occurring in these tissues. This suggests the potential of exosomes to be used as non-invasive biomarkers for diagnosing and tracking the progression of the disease. Understanding the immune microenvironment of OLP and the role of exosomes within this context is critical for advancing our knowledge of OLP pathogenesis and identifying new diagnostic and therapeutic strategies. However, challenges remain in identifying and characterising exosomes and their clinical translation. Further research is warranted to address these challenges and fully exploit exosomes' diagnostic and therapeutic potential in OLP and other inflammatory oral diseases.

Efficacy and safety of gut microbiota-based therapies in autoimmune and rheumatic diseases: a systematic review and meta-analysis of 80 randomized controlled trials

BACKGROUND

Previous randomized controlled trials (RCTs) suggested that gut microbiota-based therapies may be effective in treating autoimmune diseases, but a systematic summary is lacking.

METHODS

Pubmed, EMbase, Sinomed, and other databases were searched for RCTs related to the treatment of autoimmune diseases with probiotics from inception to June 2022. RevMan 5.4 software was used for meta-analysis after 2 investigators independently screened literature, extracted data, and assessed the risk of bias of included studies.

RESULTS

A total of 80 RCTs and 14 types of autoimmune disease [celiac sprue, SLE, and lupus nephritis (LN), RA, juvenile idiopathic arthritis (JIA), spondyloarthritis, psoriasis, fibromyalgia syndrome, MS, systemic sclerosis, type 1 diabetes mellitus (T1DM), oral lichen planus (OLP), Crohn's disease, ulcerative colitis] were included. The results showed that gut microbiota-based therapies may improve the symptoms and/or inflammatory factor of celiac sprue, SLE and LN, JIA, psoriasis, PSS, MS, systemic sclerosis, Crohn's disease, and ulcerative colitis. However, gut microbiota-based therapies may not improve the symptoms and/or inflammatory factor of spondyloarthritis and RA. Gut microbiota-based therapies may relieve the pain of fibromyalgia syndrome, but the effect on fibromyalgia impact questionnaire score is not significant. Gut microbiota-based therapies may improve HbA1c in T1DM, but its effect on total insulin requirement does not seem to be significant. These RCTs showed that probiotics did not increase the incidence of adverse events.

CONCLUSIONS

Gut microbiota-based therapies may improve several autoimmune diseases (celiac sprue, SLE and LN, JIA, psoriasis, fibromyalgia syndrome, PSS, MS, T1DM, Crohn's disease, and ulcerative colitis).

Oral Lichen Planus: An Updated Review of Etiopathogenesis, Clinical Presentation, and Management

Lichen planus (LP) is a chronic idiopathic immune-mediated inflammatory condition. LP is a heterogeneous disease with varied clinical presentations having different natural history, prognosis, sequelae, and outcomes. It can affect skin, hair, nails, and mucosae. Mucosal LP (including oral LP) tends to be persistent and resistant to treatment, compared to cutaneous LP. Oral LP (OLP) is broadly divided into two main categories: hyperkeratotic (usually asymptomatic) and erosive (commonly symptomatic). It can present with symptoms including odynophagia, dysphagia, dysgeusia, and sensitivity to hot spicy foods. Apart from the superficial epidermal changes, which vary with the type of clinical presentation, histopathologically oral LP shows a unifying similar and consistent feature of a lichenoid interface dermatitis. Recently, researchers have highlighted the critical role played by IL-17 in the pathogenesis of OLP. World Health Organization has categorized oral LP as one of the oral potentially malignant disorders (OPMD), albeit with a low risk of malignant transformation. Also, in the last couple of years there have been various reports on the usage of newer drugs like anti-IL17, anti-IL12/23, anti-IL 23, PDE4 inhibitors, and JAK inhibitors in the management of refractory OLP. The principal aim of treatment still remains to resolve the symptoms, prolong the symptoms free period, and reduce the risk of potential malignant transformation. We have described many new revelations made in recent times regarding the etiopathogenesis, associated conditions as well as management of OLP. Thus, the objective of this review is to present a comprehensive up-to-date knowledge including the recent advances made regarding OLP.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Psychological Functioning of Women Diagnosed with Lichen Planus and Other Diseases of the Oral Cavity-Explorative Study

The role of psychosocial factors in the development of changes in lichen planus and other diseases of the oral cavity has been implicated, but is still understudied. Therefore, the aim of our study was to describe the specific profile of psychological functioning of patients with these diseases, including the role of temperamental traits, action-oriented personality components, and self-esteem. In total, 94 adult women participated in the study: (1) with lichen planus (LP; n = 46; M_age = 54.80, SD = 12.53), (2) with other oral conditions (n = 25; M_age = 34.76, SD = 16.03), (3) without chronic disease (n = 24; M_age = 40.96, SD = 13.33). The following questionnaires were used: ZKA-PQ/SF, Polish Adaptive and Maladaptive Perfectionism Questionnaire, ACS-90, PROCOS, and MSEI. Results indicated no significant differences in temperament dimensions between studied groups. However, women diagnosed with LP presented lower levels of maladaptive perfectionism and social support than healthy women. Furthermore, women with LP also obtained lower scores for social resourcefulness and higher scores for moral self-approval than healthy women. Summarizing, patients with LP often use compensatory mechanisms that negatively affect their social functioning; thus diagnostic/therapeutic programs directed towards those group should be holistic, including psychologists and psychiatrists who support patients' psychological well-being.

Single-cell immune profiling reveals immune responses in oral lichen planus

Introduction

Oral lichen planus (OLP) is a common chronic inflammatory disorder of the oral mucosa with an unclear etiology. Several types of immune cells are involved in the pathogenesis of OLP.

Methods

We used single-cell RNA sequencing and immune repertoire sequencing to characterize the mucosal immune microenvironment of OLP. The presence of tissue-resident memory CD8+ T cells are validated by multiplex immunofluorescence.

Results

We generated a transcriptome atlas from four OLP biopsy samples and their paired peripheral blood mononuclear cells (PBMCs), and compared them with two healthy tissues and three healthy PBMCs samples. Our analysis revealed activated tissue-resident memory CD8+ T cells in OLP tissues. T cell receptor repertoires displayed apperant clonal expansion and preferrential gene pairing in OLP patients. Additionally, obvious BCR clonal expansion was observed in OLP lesions. Plasmacytoid dendritic cells, a subtype that can promote dendritic cell maturation and enhance lymphocyte cytotoxicity, were identified in OLP. Conventional dendritic cells and macrophages are also found to exhibit pro-inflammatory activity in OLP. Cell-cell communication analysis reveals that fibroblasts might promote the recruitment and extravasation of immune cells into connective tissue.

Discussion

Our study provides insights into the immune ecosystem of OLP, serving as a valuable resource for precision diagnosis and therapy of OLP.

Oral Papillomatosis: Its Relation with Human Papilloma Virus Infection and Local Immunity—An Update

Oral papilloma lesions may appear as a result of HPV infection, or not, and only special molecular methods could differentiate them. Low-risk and high-risk HPV types could induce oral HPV papillomatosis with different natural evolution, clearance and persistence mechanisms. The pathogenic mechanisms are based on the crosstalk between the oral epithelial and immune cells and this very efficient virus. HPV acts as a direct inducer in the process of transforming a benign lesion into a malignant one, the cancerization process being also debated in this paper. According to the degree of malignity, three types of papillomatous lesions can be described in the oral cavity: benign lesions, potential malign disorders and malignant lesions. The precise molecular diagnostic is important to identify the presence of various virus types and also the virus products responsible for its oncogenicity. An accurate diagnostic of oral papilloma can be established through a good knowledge of etiological and epidemiological factors, clinical examination and laboratory tests. This review intends to update the pathogenic mechanisms driving the macroscopic and histological features of oral papillomatosis having HPV infection as the main etiological factor, focusing on its interreference in the local immunity. In the absence of an accurate molecular diagnostic and knowledge of local immunological conditions, the therapeutic strategy could be difficult to decide.

The efficacy of henna (Lawsonia inermis L.) mouthwash versus chlorhexidine gluconate 0.2% mouthwash as adjuvant therapy of oral lichen planus: A randomized double-blind clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

In modern medicine, some traditional remedies are introduced to be effective in treatment. Accordingly, the henna plant (Lawsonia inermis L.) is studied more than before. Previous studies have shown many medical properties for henna, such as anti-inflammatory and anti-fungal properties.

AIM OF THE STUDY

Oral lichen planus (OLP) is a common mucocutaneous disease with chronic immunomodulatory disruptions. Topical corticosteroids are the first line of OLP treatment. Previous studies have suggested different adjunctive therapies for preventing the side effects of corticosteroids overuse. This study aimed to compare the effects of henna and chlorhexidine mouthwashes as adjunctive therapy.

MATERIALS AND METHODS

This parallel-group, double-blind, randomized controlled study was conducted on forty OLP patients. Luteolin content was determined in Henna mouthwash composed of 2% aqueous extract of henna, 2% ethanol, 10% glycerol, and 0.1% methylparaben distilled water. Henna or chlorhexidine mouthwashes were prescribed twice daily as an adjuvant to the topical corticosteroid treatment. Visual analog scale (VAS) index and Thongprasom rating were used to measure pain intensity and clinical signs of patients at days 0,7, and 14. The collected data were analyzed using SPSS software (version 26.0; SPSS). Ordinal logistic regression was used to investigate the effect of independent variables on Thongprasom and VAS scores.

RESULTS

In this clinical trial, 82.6% of the participants were women. There was no difference between the two study groups in terms of VAS scores (p = 0.404) and clinical features (p = 0.305) in the second follow-up visit. All drug regimens caused clinical signs and symptoms relief.

CONCLUSIONS

There was no significant difference between the groups receiving topical corticosteroid supplementation, neither henna mouthwash nor chlorhexidine mouthwash. The therapeutic effects of henna mouthwash in the main or adjuvant treatment of OLP need more evaluation in future research. Henna mouthwash can be a good alternative to chlorhexidine mouthwash if no side effects are reported.

Oral Microbiome Research on Oral Lichen Planus: Current Findings and Perspectives

Simple Summary

Oral lichen planus is a disease of the oral mucosa, which frequently affects women aged 40 years or older. Though the T cell-mediated immune response is involved in the development of oral lichen planus, attempts to identify a microorganism that causes the disease have been unsuccessful. Recent studies on the development of oral lichen planus are focusing on the role of the oral microbiome, which includes oral microbiota and their products, and the host environment. The role of the human microbiome in various diseases has been identified and regulating the microbiome is becoming important in personalized medicine. In this review, we summarized current findings on the role of the oral microbiome in the development of oral lichen planus. The homeostasis of the oral microbiome is disrupted in patients, and functional analysis of oral microbiota and oral mucosa implies that pathways involved in defense against bacterial infection and in the inflammatory response are activated in the oral lichen planus-associated oral microbiome. Though the lack of studies to date makes it difficult to conclude, further studies on the oral microbiome associated with the disease will enable a holistic understanding of the role of the oral microbiome in the development of oral lichen planus and developing a personalized therapy for the disease.

Abstract

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa with an unknown etiology. The role of oral microbes in the development of OLP has gained researchers’ interest. In this review, we summarized the findings of studies focused on the relationship between OLP and oral microbiome, which includes the composition of oral microbiota, molecules produced by oral microbiota or the host, and the oral environment of the host. According to the studies, the oral microbial community in OLP patients undergoes dysbiosis, and the microbial dysbiosis in OLP patients is more prominent in the buccal mucosa than in the saliva. However, no same microorganisms have been suggested to be associated with OLP in multiple investigations, implying that the functional aspects of the oral microbiota are more important in OLP development than the composition of the oral microbiota. According to studies on host factors that make up the oral environment, signal pathways involved in cellular processes, such as keratinization, inflammation, and T cell responses are triggered in OLP. Studies on the functional aspects of the oral microbiota, as well as interactions between the host and the oral microbiota, are still lacking, and more research is required.

Association of human gut microbiota with rare diseases: A close peep through

The human body harbors approximately 1014 cells belonging to a diverse group of microorganisms. Bacteria outnumbers protozoa, fungi and viruses inhabiting our gastrointestinal tract (GIT), commonly referred to as the "human gut microbiome". Dysbiosis occurs when the balanced relationship between the host and the gut microbiota is disrupted, altering the usual microbial population there. This increases the susceptibility of the host to pathogens, and chances of its morbidity. It is due to the fact that the gut microbiome plays an important role in human health; it influences the progression of conditions varying from colorectal cancer to GIT disorders linked with the nervous system, autoimmunity, metabolism and inheritance. A rare disease is a lethal and persistent condition affecting 2-3 people per 5,000 populaces. This review article intends to discuss such rare neurological, autoimmune, cardio-metabolic and genetic disorders of man, focusing on the fundamental mechanism that links them with their gut microbiome. Ten rare diseases, including Pediatric Crohn's disease (PCD), Lichen planus (LP), Hypophosphatasia (HPP), Discitis, Cogan's syndrome, Chancroid disease, Sennetsu fever, Acute cholecystitis (AC), Grave's disease (GD) and Tropical sprue (TS) stands to highlight as key examples, along with personalized therapeutics meant for them. This medicinal approach addresses the individual's genetic and genomic pathography, and tackles the illness with specific and effective treatments.

Probiotics as Potential Biological Immunomodulators in the Management of Oral Lichen Planus: What's New?

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disorder with multifactorial aetiology and malignant transformation potential. Despite the treatments so far identified, new tailored and safe specific measures are needed. Recently, human microbiota imbalance has been linked to several immune-mediated diseases, opening new therapeutic perspectives for probiotics; besides their ability to directly interact with the host microbiota, they also display a strain-specific immune-modulatory effect. Thus, this non-systematic review aims to elucidate the molecular pathways underlying probiotic activity, mainly those of Lactobacilli and Bifidobacteria and their metabolites in OLP pathogenesis and malignant transformation, focusing on the most recent in vitro and in vivo research evidence. Findings related to their activity in other immune-mediated diseases are here included, suggesting a probiotic translational use in OLP. Probiotics show immune-modulatory and microbiota-balancing activities; they protect the host from pathogens, hamper an excessive effector T cell response, reduce nuclear factor-kappa B (NF-kB) signalling and basal keratinocytes abnormal apoptosis, shifting the mucosal response towards the production of anti-inflammatory cytokines, thus preventing uncontrolled damage. Therefore, probiotics could be a highly encouraging prevention and immunotherapeutic approach for a safer and more sustainable OLP management.

[Structural Analysis of Salivary Bacterial and Fungal Microbiome in Oral Lichen Planus Patients]

Objective

To explore the differences of oral mycobiome and bacteriome between the healthy controls (H) and oral lichen planus (OLP) patients, and the co-occurrence patterns of the salivary mycobiome and bacteriome and the association with host immunity.

Methods

Saliva samples were collected from clinical OLP patients (n=35) and healthy volunteers (n=18). Microbiome DNA was extracted for bacterial 16S rRNA genes sequencing and fungal internal transcribed spacer 2 (ITS2) sequencing. Bioinformatics analysis was performed on the data.The levels of IL-17 and IL-23, two pro-inflammatory cytokines, in the saliva were examined, and their correlation with the bacteria was analyzed.

Results

There was no significant difference in the overall community structure of the mycobiome and the bacteriome between OLP patients and healthy controls. The abundance of Prevotellaand Solobacterium in the saliva bacteriome was significantly increased in the OLP group (P<0.05), and the relative abundance of Candidaand Aspergillusin the saliva mycobiome was also significantly increased (P<0.05). The co-occurrence pattern of the salivary mycobiome and bacteriome showed that the aforementioned difference was not related. However, the correlation between Aspergillusand bacteria was altered in the H group and the OLP group, and co-occurrence was reduced in the latter group. The level of IL-17 in the saliva was significantly increased in the OLP group. IL-17 and clinical scores were significantly correlated with the abundance of Porphyromonas.

Conclusion

The increased abundance of Prevotella, Solobacterium, Candida, and Aspergillus was associated with the pathogenesis of OLP, and the changes of the microbiome co-occurrence relationship and host immunity may be involved in the pathogenesis of OLP.

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific etiologic factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T-cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T-cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research toward identifying potential therapeutic targets.

Candida species colonization in oral lichen planus: A meta-analysis

OBJECTIVE

Oral lichen planus (OLP) is a common chronic inflammatory disease that affects 1%-2% of the population. Candida species superinfection can aggravate the symptoms of OLP, especially of the erosive forms, and promote malignant transformation by producing carcinogenics as nitrosamines or acetaldehyde. On the other hand, antifungal treatment of Candida-infected OLPs improves the clinical symptoms of the disease. The objective of this study is to assess the possible influence of Candida species colonization in oral lichen planus.

METHODS

A search for studies on Candida and oral lichen planus was performed in the following databases: PubMed (MEDLINE, Cochrane Library), Web of Science (WoS), and Scopus. Data analysis: The estimated prevalence of Candida detection in OLP was calculated according to the DerSimonian and Laird random model. For dichotomous outcomes, the estimates of effects of an intervention were expressed as odds ratio (OR) using Mantel-Haenszel (M-H) method with 95% confidence intervals.

RESULTS

Twenty-four studies were included in this meta-analysis. The estimated prevalence of Candida species detection in oral lichen planus (OLP) lesions was 37.00% (95% CI: 30.52-43.72%). OLP patients were almost 2½ times more likely to be infected by Candida species compared to healthy controls (OR: 2.48, P < 0.001). Likewise, Candida species superinfection was more likely in erosive OLP forms (OR: 2.53, P < 0.001), and by non-albicans Candida species (OR: 2.33, P = 0.02).

CONCLUSIONS

More than one-third of OLP lesions are infected by Candida species, modifying their biological behavior.

The Implication of Candida Infection in Oral Lichen Planus Lesions

Objectives: The purpose of this study is to determine if superimposed infection with Candida species in oral lichen planus exacerbates the clinical symptoms and lesions. Methodology:We conducted a retrospective study on the medical charts of oral lichen planus (OLP) patients diagnosed by clinical and histopathological criteria. A baseline demographic, anamnestic, clinical data, results of the oral candida investigations were analyzed and recorded for all patients. Results:From a total number of 203 OLP patients, oral candidiasis was diagnosed in 75 (36.94%) cases. There was no statistical significance between the clinical forms of lichen planus and the presence of Candida infection. Of all encountered Candida species, Candida albicans was most commonly detected, followed by Candida krusei, Candida lusitaniae, and Candida tropicalis. Conclusion:Although our study is limited regarding the sample size and no statistically significant difference has been found between clinical features of OLP and oral candidiasis, a routine screening of OLP patients for oral candidiasis and a preventive antifungal strategy in the OLP treatment schedule is needed.

A Comparison of Clinical Efficiency of Photodynamic Therapy and Topical Corticosteroid in Treatment of Oral Lichen Planus: A Split-Mouth Randomised Controlled Study

Background: The aim of the study was to compare the effectiveness of photodynamic therapy (PDT) to steroid therapy in the treatment of oral lichen planus (OLP). Due to the lack of commercially available drug carriers, innovative proprietary solutions were used for both the photosensitiser and the steroid carrier—in the first case to shorten and in the second to extend the contact of the active substance with the mucosa. Methods: A prospective, randomised, single-blind, 12-week full contralateral split-mouth clinical trial of 30 patients with bilateral oral lichen planus was conducted. The prepared matrices were incorporated with active substances methylene blue 5% and 0,05% triamcinolone. The size of lesions, Thongprasom, ABISIS, and VAS scale were evaluated. Results: Relatively high rates of complete remission of lichen were demonstrated: immediately after treatment, 33.3% with PDT and 22.2% with triamcinolone (TA), and after 3 months, 54.2% with PDT and 62.9% with TA. After 3 months of treatment, a reduction in the area of evaluated lesions of 52.7% for PDT and 41.7% for TA was achieved. Conclusion: In situations of topical or general contraindications to oral corticosteroids, resistance to them, or the need for repeated treatment in a short period of time, PDT appears to be a very promising treatment option.