Putative salivary protein biomarkers for the diagnosis of oral lichen planus: a case-control study

Emerging potential of phototherapy in management of symptomatic oral lichen planus: A systematic review of randomised controlled clinical trials

Phototherapy incorporating photobiomodulation therapy and antimicrobial photodynamic therapy has been utilised as antioxidants in symptomatic oral lichen planus (OLP) management; however, its role of intervention remains controversial. The aim of this systematic review of CRD42021227788 PROSPERO (an international prospective register of systematic reviews in health and social care) registration number was to oversee and determine phototherapy efficacy in patients with symptomatic OLP, identifying and bridging the literature gaps by proposing recommendations for future studies. A search strategy was developed in consistent with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Various electronic databases were exercised to search for randomised controlled clinical trials (RCTs). Several search engines were employed to analyse a total of 177 studies of which nine included. A wide range of utilised laser and light-emitted diode wavelengths between 630 and 808 nm and irradiance ranged between 10 and 13 mW/cm² were noted. 67% of studies reported a high risk of bias and a high heterogeneity obtained from numerical data for quantitative analysis, therefore meta-analysis was impossible to conduct. Despite inconsistency and diversity in phototherapy parameters, treatment protocols, photosensitiser (type, concentration and method of application) and outcome assessment tools, the majority of the studies showed positive results compared with standard care treatments. Hence, a necessity to perform well-designed RCTs with robust methodology is warranted, after acknowledging the current drawbacks and addressing the suggested recommendations highlighted in our review. Moreover, advanced knowledge in understanding further phototherapy-antioxidants molecular mechanistic in symptomatic OLP is required.

Platelet-rich plasma protein as a therapeutic regimen for oral lichen planus: An evidence-based systematic review

Oral Lichen Planus (OLP), an autoimmune disorder of unclear pathogenesis affects quality of life of affected individual. Intervention regimens are multiple and still evolving due to its resistance to recover and ability to recur. Platelet rich Plasma (PRP) is a newer, promising treatment modality tested by researchers because of its low cost and negligible adverse effects. Articles were retrieved from search engines of PubMed / Medline, Scopus and Web of Science which fulfilled the eligibility criteria. Cochrane risk of bias tool assessed quality of clinical studies and Joanna Briggs Institute for case reports. A total of 4 articles were included for the systematic review, of which 2 are clinical trials and 2 case reports. All cases were of erosive nature. PRP in case reports were administered when patients did not respond to conventional therapy. PRP demonstrated effective therapeutic benefit in regards to outcome of pain and lesion appearance. PRP can be considered as a potential alternative therapy in treating non-responsive OLP. Further studies are recommended to arrive at a definitive conclusion.

Metataxonomic and metaproteomic profiling of the oral microbiome in oral lichen planus - a pilot study

Background

A growing body of evidence demonstrates a different bacterial composition in the oral cavity of patients with oral lichen planus (OLP).

Patients and methods

Buccal swab samples were collected from affected and non-affected sites of six patients with reticular OLP and the healthy oral mucosa of six control subjects. 16S rRNA gene MiSeq sequencing and mass spectrometry-based proteomics were utilised to identify the metataxonomic and metaproteomic profiles of the oral microbiome in both groups.

Results

From the metataxonomic analysis, the most abundant species in the three subgroups were Streptococcus oralis and Pseudomonas aeruginosa, accounting for up to 70% of the total population. Principal Coordinates Analysis showed differential clustering of samples from the healthy and OLP groups. ANCOM-BC compositional analysis revealed multiple species (including P. aeruginosa and several species of Veillonella, Prevotella, Streptococcus and Neisseria) significantly over-represented in the control group and several (including Granulicatella elegans, Gemella haemolysans and G. parahaemolysans) in patients with OLP. The metaproteomic data were generally congruent and revealed that several Gemella haemolysans-belonging peptidases and other proteins with inflammatory and virulence potential were present in OLP lesions.

Conclusion

Our data suggest that several bacterial species are associated with OLP. Future studies with larger cohorts should be conducted to determine their role in the aetiology of OLP and evaluate their potential as disease biomarkers.

Differential genotypes of TNF-α and IL-10 for immunological diagnosis in discoid lupus erythematosus and oral lichen planus: A narrative review

Discoid lupus erythematosus and oral lichen planus are chronic systemic immune system-mediated diseases with unclear etiology and pathogenesis. The oral mucosa is the common primary site of pathogenesis in both, whereby innate and adaptive immunity and inflammation play crucial roles. The clinical manifestations of discoid lupus erythematosus on the oral mucosa are very similar to those of oral lichen planus; therefore, its oral lesion is classified under oral lichenoid lesions. In practice, the differential diagnosis of discoid lupus erythematosus and oral lichen planus has always relied on the clinical manifestations, with histopathological examination as an auxiliary diagnostic tool. However, the close resemblance of the clinical manifestations and histopathology proves challenging for accurate differential diagnosis and further treatment. In most cases, dentists and pathologists fail to distinguish between the conditions during the early stages of the lesions. It should be noted that both are considered to be precancerous conditions, highlighting the significance of early diagnosis and treatment. In the context of unknown etiology and pathogenesis, we suggest a serological and genetic diagnostic method based on TNF-α and IL-10. These are the two most common cytokines produced by the innate and adaptive immune systems and they play a fundamental role in maintaining immune homeostasis and modulating inflammation. The prominent variability in their expression levels and gene polymorphism typing in different lesions compensates for the low specificity of current conventional diagnostic protocols. This new diagnostic scheme, starting from the immunity and inflammation of the oral mucosa, enables simultaneous comparison of discoid lupus erythematosus and oral lichen planus. With relevant supportive evidence, this information can enhance physicians’ understanding of the two diseases, contribute to precision medicine, and aid in prevention of precancerous conditions.

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.

Recognizing the salivary panomics for the clinical application in oral potentially malignant disorders

Oral cancer arises as a result of multistep carcinogenic progress from precursor lesion to oral squamous cell carcinoma through collective mutational process occur in the stem cells of mucosal epithelium. The detection of such oral potentially malignant disorders (OPMDs)/cancer in subclinical level will greatly improve the prognosis of a patient. The highly specific and sensitive salivary biomarkers have functioned in detection, prediction, surveillance and therapeutic monitoring of the diseases of interest. The aim of the review is to appraise various salivary biomarkers for the clinical utility in OPMDs. An electronic web-supported search was performed via PubMed, ScienceDirect and Google Scholar search engine since the year 2015–2019. A total of 28 research articles were selected for the review after screening and assessment. The various genomic, transcriptomic, proteomic, metabolomic and miscellaneous markers were analyzed and their characteristics and clinical application in OPMD patients were discussed. miR-21, miR-31, miR-84, H3F3A mRNA + IL-8P, matrix metalloproteinase-9, chemerin, tumor necrosis factor-alpha, cytokeratin-10, ornithine + O-hydroxybenzoate + R5F, 8-hydroxy-2-deoxyguanosine, malondialdehyde, Vitamin E and Vitamin C are identified as potential markers for OPMD patients. Scientifically validated, reliable and economical clinical biomarkers in OPMDs would serve as evidence-based treatment from patient point of view. Further longitudinal studies are needed to verify the accuracy and validate the applicability of these diagnostic/prognostic markers. Saliva has been reported as a valuable noninvasive valuable tool in biomarker identification. Recent advancements in salivary biomarker identification techniques lead to various potential biomarkers with precise outcome. The utilization of these biomarkers for the clinical application in OPMDs depends on the feasibility and personal choice of the clinician.

Differentially Expressed Salivary Proteins in Dental Caries Patients

Dental caries is a multifactorial disease mainly caused by cariogenic bacteria commonly found in the oral cavity. Dental caries may cause demineralization of the tooth, cavitation, hypersensitivity, pulp inflammation, and even tooth loss if left untreated. Saliva secreted in the oral cavity can serve as a tool for identification of biomarkers for early detection of diseases. In the present study, differential expression of salivary proteins from 33 dental caries patients was compared with 10 control subjects. The unstimulated saliva was analyzed by 12% SDS-PAGE and two-dimensional gel electrophoresis. Gelatin and casein zymography was performed to check for protease activity. Also, salivary IgAs from both groups were compared by sandwich ELISA technique. Dental caries patient's saliva showed decreased caseinolytic and increased gelatinolytic activity probably due to metalloproteases and cathepsins. Mean salivary levels of sIgA were also significantly higher (p < 0.018) in dental caries saliva samples. The 2D electrophoresis profile of both the groups showed regions on gel with visually detectable alterations in protein expression. The present study is among the few initial studies in the locality for identification of protein differences in saliva from dental caries patients and has demonstrated a good potential to identify alterations. However, a large population-based analysis is required to validate these findings to be translated as a tool for indicative applications.

Saliva Proteomics as Fluid Signature of Inflammatory and Immune-Mediated Skin Diseases

Saliva is easy to access, non-invasive and a useful source of information useful for the diagnosis of serval inflammatory and immune-mediated diseases. Following the advent of genomic technologies and -omic research, studies based on saliva testing have rapidly increased and human salivary proteome has been partially characterized. As a proteomic protocol to analyze the whole saliva proteome is not currently available, the most common aim of the proteomic analysis is to discriminate between physiological and pathological conditions. The salivary proteome has been initially investigated in several diseases: oral squamous cell carcinoma and oral leukoplakia, chronic graft-versus-host disease, and Sjögren's syndrome. Otherwise, salivary proteomics studies in the dermatological field are still in the initial phase, thus the aim of this review is to collect the best research evidence on the role of saliva proteomics analysis in immune-mediated skin diseases to understand the direction of research in this field. The results of PRISMA analysis reported herein suggest that human saliva analysis could provide significant data for the diagnosis and prognosis of several immune-mediated and inflammatory skin diseases in the next future.

Oral lichen planus: a microbiologist point of view

Oral lichen planus (OLP) is a chronic disease of uncertain etiology, although it is generally considered as an immune-mediated disease that affects the mucous membranes and even the skin and nails. Over the years, this disease was attributed to a variety of causes, including different types of microorganisms. This review analyzes the present state of the art of the disease, from a microbiological point of view, while considering whether or not the possibility of a microbial origin for the disease can be supported. From the evidence presented here, OLP should be considered an immunological disease, as it was initially proposed, as opposed to an illness of microbiological origin. The different microorganisms so far described as putative disease-causing agents do not fulfill Koch’s postulates; they are, actually, not the cause, but a result of the disease that provides the right circumstances for microbial colonization. This means that, at this stage, and unless new data becomes available, no microorganism can be envisaged as the causative agent of lichen planus.

The expression of membrane-bound complement regulatory proteins CD46, CD55 and CD59 in oral lichen planus

OBJECTIVE

To investigate the expression levels of membrane-anchored complement regulatory proteins (mCRPs), CD46, CD55 and CD59 in oral lichen planus (OLP), and evaluate the activation status of complement.

DESIGN

Thirty-seven cases of OLP patients (20 non-erosive OLP and 17 erosive OLP) and twenty healthy controls were recruited in this study. The proteins and mRNA expression levels of CD46, CD55 and CD59 in OLP tissues were detected by western blotting and RT-qPCR respectively, and the expression levels of complement C3 and sC5b-9 in OLP patients' saliva were detected by ELISA to evaluate the activation status of complement. In addition, mucosa tissues of another 3 non-erosive OLP patients and another 3 healthy controls were collected, and the epithelial layer of two groups were separated to culture primary keratinocytes in vitro. Immunofluorescence was used to further detect the expression of mCRPs at the cellular level.

RESULTS

The levels of CD46, CD55 and CD59 in OLP tissues and cells were significantly decreased compared with those of the healthy control group, and the level of complement C3 in the patients' saliva was significantly decreased, while the level of sC5b-9 was increased.

CONCLUSIONS

These results suggest that the reduced expression of mCRPs keeps the complement system in a continuously active state, which may be the reason of the persistent local immune inflammatory state in OLP. This study aimed to provide new insights for the etiology and therapy of OLP.

A shotgun proteomic approach reveals novel potential salivary protein biomarkers for asthma

OBJECTIVE

The aim of this study was to determine if there is an association between the salivary protein profile and disease control in asthma.

METHODS

Thirty asthmatic patients (17 adults and 13 children) participated in this study. Saliva samples were collected from healthy subjects, controlled and uncontrolled asthmatics. Individual samples from each group were combined to form a pooled sample, from which proteomic analysis was performed using gel-based quantitative proteomics.

RESULTS

Fourteen out of thirty asthmatics were classified to be controlled asthma. Most of asthmatics received inhaled corticosteroids as the controller medications. SDS-PAGE showed predominant bands at high molecular weight in asthmatic saliva compared to that of the controls. Shotgun proteomic analyses indicated that 193 salivary proteins were expressed in both controlled and uncontrolled asthmatics. They were predicted to associate with proteins involved in pathogenesis of asthma including IL-5, IL-6, MCP-1, VEGF, and periostin and asthma medicines (Cromolyn, Nedocromil, and Theophylline). Nucleoside diphosphate kinase (NME1-NME2) only expressed in controlled asthmatics whereas polycystic kidney and hepatic disease 1 (PKHD1)/fibrocystin, zinc finger protein 263 (ZNF263), uncharacterized LOC101060047 (ENSG00000268865), desmoglein 2 (DSG2) and S100 calcium binding protein A2 (S100A2) were only found in uncontrolled asthma. Therefore, the six proteins were associated with disease control in children and adults with asthma.

CONCLUSION

Our findings suggest that NME1-NME2, PKHD1, ZNF 263, uncharacterized LOC101060047, DSG 2 and S100 A2 in saliva are associated with disease control in asthma.

Saliva proteomics from children with caries at different severity stages

OBJECTIVE

To perform a comparative analysis of saliva protein profile of patients with early childhood caries at different levels of severity and caries-free individuals.

MATERIALS AND METHODS

Stimulated saliva samples were collected from 126 children (2-6 years old), classified according to the ICDAS II, and divided into 3 groups (n = 42): caries-free (CF), enamel caries (EC), and dentine caries (DC). Samples were digested and analyzed by nanoUPLC coupled with a mass spectrometry. Data analyses were conducted with Progenesis QI for Proteomics Software v2.0. Gene Ontology (GO) terms and protein-protein interaction analysis were obtained.

RESULTS

A total of 306 proteins (≈6 peptides) were identified. Among them, 122 were differentially expressed in comparisons among children with different caries status. Out of the 122 proteins, the proteins E2AK4 and SH3L2 were exclusively present in groups CF and EC, respectively, and 8 proteins (HAUS4, CAH1, IL36A, IL36G, AIMP1, KLHL8, KLH13, and SAA1) were considered caries-related proteins when compared to caries-free children; they were up-regulated proteins in the caries groups (EC and DC).

CONCLUSION

The identification of exclusive proteins for caries-free or carious-related conditions may help in understanding the mechanisms of caries and predicting risk as well as advancing in caries control or anti-caries approaches.

Diagnostic Criteria of Oral Lichen Planus: A Narrative Review

Oral lichen planus (OLP) is a disease with unclear etiology or pathogenesis, categorized by the World Health Organization as oral lichenoid lesions (OLL; interface mucositis or lichenoid mucositis) into a group of potentially malignant disorders. The diagnosis of OLP is challenging because the clinical and histopathologic features are frequently seen in OLP, OLL and/or other mucosal diseases with lichenoid characteristics. Furthermore, OLP has a dynamic nature. Finally, an early and precise diagnosis can play a decisive role, allowing timely treatment and thus improving the patient quality of life. This article summarizes the state-of-the-art regarding OLP and OLL and discusses the challenges faced on making an accurate diagnosis, aiming to provide a practical guideline for the postgraduates and oral physicians in reaching the diagnosis of these lesions.

Complement split product C3c in saliva as biomarker for periodontitis and response to periodontal treatment

Background and Objective

The complement system is engaged in inflammatory reactions both in the periodontal pockets and in the periodontium itself, where it can mediate tissue destruction. The aim of this study was, first, to compare salivary levels of the total complement system protein C3 and its split product, fluid‐phase C3c in patients with periodontitis and periodontally healthy controls. Next, to determine if C3 and C3c levels had biomarker potential in diagnosing and monitoring periodontitis and its treatment. We hypothesized that salivary levels of total C3 and the split product C3c associated with the severity of periodontitis and reflected decreased inflammatory activity after periodontal treatment.

Methods

At baseline, stimulated saliva samples were collected from patients with periodontitis (n = 18) and periodontally healthy controls (n = 15). Subsequently, non‐surgical periodontal treatment was performed in the patients, and saliva sampling from patients was repeated two‐, six‐, and twelve weeks post‐treatment (NCT02913248 at clinicaltrials.gov).

The patients were grouped as good and poor responders to treatment according to the achieved reduction in bleeding on probing (BOP).

Salivary levels of C3 and C3c were quantified using sandwich ELISA.

Results

Patients with periodontitis had higher baseline levels of both total C3 and the split product C3c in saliva than did periodontally healthy controls (P < .0001). Receiver operating curve (ROC) analyses discriminated patients with periodontitis from controls based on both C3 (AUC (area under curve) = 0.91, P < .001) and C3c levels (AUC = 0.84, P < .001) in saliva. Periodontal treatment improved all clinical parameters (P < .01). Good responders (n = 10) had lower baseline levels of C3c than poor responders (n = 8), (P < .05), and baseline levels of C3c discriminated between good and poor responders (AUC = 0.80, P < .05).

Conclusion

In conclusion, patients with periodontitis had higher salivary levels of C3c, and the C3c levels were predictive of reductions in BOP, that is, the poor responders. This suggests that salivary C3c levels possess potential to serve as a biomarker predicting the clinical response to non‐surgical periodontal treatment.

Saliva and Oral Diseases

Saliva is a fascinating biological fluid which has all the features of a perfect diagnostic tool. In fact, its collection is rapid, simple, and noninvasive. Thanks to several transport mechanisms and its intimate contact with crevicular fluid, saliva contains hundreds of proteins deriving from plasma. Advances in analytical techniques have opened a new era-called "salivaomics"-that investigates the salivary proteome, transcriptome, microRNAs, metabolome, and microbiome. In recent years, researchers have tried to find salivary biomarkers for oral and systemic diseases with various protocols and technologies. The review aspires to provide an overall perspective of salivary biomarkers concerning oral diseases such as lichen planus, oral cancer, blistering diseases, and psoriasis. Saliva has proved to be a promising substrate for the early detection of oral diseases and the evaluation of therapeutic response. However, the wide variation in sampling, processing, and measuring of salivary elements still represents a limit for the application in clinical practice.

The Relationship between the Concentration of Salivary Tyrosine and Antioxidants in Patients with Oral Lichen Planus

The diagnosis of oral lichen planus (OLP) is based on clinical examination and histopathological criteria. Noninvasive diagnostics of saliva may be considered as a confirmation of OLP diagnosis and a potential alternative to an invasive method. The objective of the present study was to evaluate the relationship between the level of tyrosine (Tyr) as well as antioxidants like uric acid (UA) and glutathione peroxidase (GPx) activity in the saliva of patients with OLP in comparison with the control group (healthy subjects without any oral changes). A total of 40 patients with OLP and 40 healthy volunteers were selected for the study based on the modified WHO diagnostic (clinical and histopathological) criteria. High-performance liquid chromatography (HPLC) was performed for Tyr concentration, while GPx activity and uric acid levels were determined by a colorimetric method. The concentrations of Tyr, UA, and GPx activity were statistically lowered in OLP patients compared to the control group. All examined parameters correlated strongly and positively with each other. Mean values of salivary UA concentrations differed between the groups of OLP patients (reticular and erosive forms) and controls (206.66 vs. 196.54 vs. 218.49 μmol/L, respectively, p = 0.001). A similar trend was demonstrated in salivary Tyr concentration which differed statistically between the study and control groups (0.08 vs. 0.07 vs. 0.13 μmol/L, respectively, p = 0.001). Determining of a relationship between the concentrations of Tyr, UA, and GPx activity may be useful in the prognosis of OLP. The HPLC method may be employed, as an additional noninvasive diagnostic procedure to screen OLP patients, during the routine diagnostics of salivary biochemical parameters such as aromatic amino acids.