Salivary microbiota and inflammation-related proteins in patients with psoriasis

Assessment of salivary biomarkers in psoriasis: a comprehensive scoping review

OBJECTIVE

To map the evidence on altered salivary biomarkers in individuals with psoriasis.

STUDY DESIGN

A comprehensive literature search was conducted across six databases and gray literature sources using keywords related to psoriasis and salivary biomarkers, with no restrictions on time or language, up to November 2024. Studies evaluating salivary biomarkers in humans with psoriasis were considered eligible. Identified outcomes were categorized based on biomarker type and analyzed descriptively.

RESULTS

A total of 661 studies were initially identified, of which 22 met the inclusion criteria. These comprised 15 cross-sectional studies, 6 cohort studies, and 1 randomized clinical trial, collectively involving 987 individuals with psoriasis. The primary altered salivary biomarkers identified included inflammatory cytokines (IL-1β, IL-2, IL-6, IL-10, TNF-α, INF-γ), oxidative stress mediators (nitric oxide, nitrotyrosine), antioxidant enzymes (catalase, superoxide dismutase), immunological markers (salivary alpha-amylase, secretory immunoglobulin A), and stress-related hormones. Many of these biomarkers were significantly associated with disease severity and therapeutic response.

CONCLUSION

Cortisol, inflammatory cytokines and oxidative stress mediators are the most frequently altered salivary biomarkers in individuals with psoriasis. However, the methodological heterogeneity among the studies highlights the need for well-designed prospective studies with representative sample sizes to validate these findings.

Characterization of potential salivary biomarkers in Behçet's disease

Diagnosis of Behçet's disease (BD) has always been a challenging task due to the heterogeneity and complexity of the disease, while available literature on BD biomarkers is largely inconclusive. The aim of this study was to evaluate the expression of a panel of salivary biomarkers in a group of BD patients and test their association with BD. The study population comprised 23 BD patients (12 females and 11 males) and a control group of age and gender-matched healthy individuals. Enzyme-linked immunosorbent assays were used to test the expression of 5 salivary proteins including: interleukin 1β (IL-1β), epidermal growth factor (EGF), endothelin, vascular endothelial growth factor (VEGF) and transferrin (TrF). BD activity was evaluated using the International Society for Behçet's disease (ISBD) current activity form. Salivary endothelin, EGF and VEGF were significantly higher in the BD group compared to controls (16.3 Vs. 7.7 pg/ml, 194.5 Vs. 163.4 pg/ml and 262 Vs. 150.2 pg/ml, p<0.05, respectively) whereas TrF was significantly lower in BD group compared to controls (497 Vs. 2206 pg/ml, p<0.001). The correlation analysis showed a trend of a positive linear association between endothelin expression and both BD activity (r=0.41) and BD activity index score (r=0.4), without reaching statistical significance (p>0.05). In conclusion, salivary TrF, endothelin, VEGF and EGF may represent potential biomarkers for BD. These findings require further validation in larger samples and different activity states of BD.

A systematic review of the implications of lipocalin-2 expression in periodontal disease

OBJECTIVE

Evidence suggests that lipocalin-2 (LCN-2), a bone-derived protein, is upregulated in periodontal diseases. This systematic review aimed to evaluate LCN-2 concentrations in individuals with periodontal diseases, identifying the most suitable body fluids for its detection, the type of periodontal disease with the highest LCN-2 expression, its association with other inflammatory markers and systemic diseases, and whether its expression can be modified by periodontal treatment.

METHODS

A systematic search of Google Scholar, PubMed, and ProQuest up to August 2024 was conducted. The studies were screened and selected by the authors according to specific eligibility criteria. Quality assessment of the included studies was performed according to the study type using STROBE statement for observational studies or the modified Jadad scale for experimental studies. The review was registered in PROSPERO (CRD42023458565).

RESULTS

In total, three thousand six hundred and thirty-eight reports were identified, of which twenty-seven were full-text assessed for eligibility, including eleven articles. Seven articles were observational, and four were experimental. Significantly elevated LCN-2 levels were reported in patients with periodontal disease across 9 studies, being higher in periodontitis rather than gingivitis. LCN-2 was mainly detected in gingival crevicular fluid (GCF) and saliva. LCN-2 expression is related to the increment of inflammatory markers, and periodontal therapy decreases LCN-2 concentrations. LCN-2 levels were aggravated when periodontitis was accompanied by obesity and type 2 diabetes.

CONCLUSION

LCN-2 is implicated in periodontal diseases, probably through the inflammation process.

Saliva as a Diagnostic Tool for Systemic Diseases-A Narrative Review

Saliva has emerged as a powerful diagnostic tool due to its non-invasive collection, straightforward storage, and ability to mirror systemic health. This narrative review explores the diagnostic potential of salivary biomarkers in detecting systemic diseases, supported by examples such as salivary proteomics' role in monitoring endocrine disorders, cancer, and viral infections. Advances in technologies like microfluidics, biosensors, and next-generation sequencing have enhanced the sensitivity and specificity of salivary diagnostics, making it a viable alternative to blood-based diagnostics. The review also evaluates challenges such as the need for standardized collection protocols, variability in salivary composition, and the integration of these technologies into clinical workflows. The findings emphasize the transformative potential of saliva in personalized medicine, especially for early disease detection and real-time health monitoring. Practical applications include its use in mass screenings and public health crises, highlighting saliva as a cornerstone for future advancements in non-invasive diagnostics.

The expression of salivary EGF, VEGF, endothelin, and transferrin in waterpipe and cigarette smokers

The aim of this study was to evaluate the effects of two forms of tobacco smoking, cigarettes and water pipe smoking (WPS), on the expression of a panel of salivary proteins in healthy adults. Three groups of age and gender-matched participants were enrolled in the study: never-smokers, cigarette smokers and WPS (N = 55 per group). Expression of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), endothelin and transferrin in unstimulated whole saliva was estimated using enzyme-linked immunosorbent assays. Statistical analysis consisted of one-way ANOVA and Tukey's post hoc tests, in addition to bioinformatics analysis. VEGF expression was the least in WPS (51.1 ± 14.5 pg/ml) compared to both controls (150.1 ± 13.8 pg/ml) and cigarette smokers (93 ± 9.9 pg/ml), with a significant difference in WPS (p < 0.001) and cigarette smokers (p < 0.01) compared to controls. Furthermore, transferrin showed the weakest expression in the WPS group (1238 ± 261.4 pg/ml) compared to controls (2205.6 ± 298.6 pg/ml) (p = 0.05) and cigarette smokers (1805.4 ± 244 pg/ml). Neither EGF nor endothelin expression showed any statistical difference between the groups (p > 0.05). Gene-gene interaction network demonstrated that FLT1, TFRC, KDR, VEGFB and PGF genes had the highest potential for interaction with the studied proteins. Further functional annotations on the identified markers in the interaction network were performed to identify HIF-1 pathways among the most relevant pathways. In conclusion, smoking habits alter the expression of salivary VEGF and transferrin, which may correspond to early sub-clinical changes in the oral mucosa. The clinical relevance of these salivary changes requires further research.

Oral Pathogens' Substantial Burden on Cancer, Cardiovascular Diseases, Alzheimer's, Diabetes, and Other Systemic Diseases: A Public Health Crisis-A Comprehensive Review

This review synthesizes the findings from 252 studies to explore the relationship between the oral pathogens associated with periodontitis, dental caries, and systemic diseases. Individuals with oral diseases, such as periodontitis, are between 1.7 and 7.5 times (average 3.3 times) more likely to develop systemic diseases or suffer adverse pregnancy outcomes, underscoring the critical connection between dental and overall health. Oral conditions such as periodontitis and dental caries represent a significant health burden, affecting 26-47% of Americans. The most important oral pathogens, ranked by publication frequency, include the herpes virus, C. albicans, S. mutans, P. gingivalis, F. nucleatum, A. actinomycetemcomitans, P. intermedia, T. denticola, and T. forsythia. The systemic diseases and disorders linked to oral infections, ranked similarly, include cancer, respiratory, liver, bowel, fever, kidney, complications in pregnancy, cardiovascular bacteremia, diabetes, arthritis, autoimmune, bladder, dementia, lupus, and Alzheimer's diseases. Evidence supports the efficacy of dental and periodontal treatments in eliminating oral infections and reducing the severity of systemic diseases. The substantial burden that oral pathogens have on cancer, cardiovascular diseases, Alzheimer's, diabetes, and other systemic diseases poses a significant public health crisis.

Oral Microbiota Variations in Psoriasis Patients Without Comorbidity

Background

Psoriasis is a chronic inflammatory skin disease, and its etiology is still unclear. There is increasing evidence suggesting that microorganisms may trigger psoriasis. However, the relationship between psoriasis and oral microbiota remains poorly understood. Our aim is to identify differences in the composition and diversity of the oral microbiota between patients with psoriasis and healthy controls, and to discover oral microbial markers for assessing the severity of psoriasis.

Methods

This study recruited 20 psoriasis patients and 20 healthy individuals, collecting their saliva to analyze the composition of the oral microbiota in psoriasis patients. We employed 16S rRNA sequencing technology and utilized various methods for oral microbiome analysis, including the Shannon Index, Gini-Simpson Index, Principal Coordinates Analysis (PCoA), non-metric multidimensional scaling (NMDS), Linear discriminant analysis Effect Size (LEfSe), Wilcoxon test, and Spearman's rank correlation.

Results

The results showed that the alpha diversity of oral microbiota was higher in psoriasis patients. The relative abundances of certain bacterial taxa differed between psoriasis and healthy individuals, including Prevotella, Prevotella 7 and Porphyromonas gingivalis, which are increased in psoriasis. We also found a positive correlation between Alloprevotella, Porphyromonas, and Neisseria with the severity of psoriasis, while Veillonella showed a negative correlation.

Conclusion

In summary, this study found significant changes in the composition of the oral microbiota in patients with psoriasis. Some oral bacteria are associated with psoriasis severity. It provides a new perspective on the relationship between the oral microbiota and psoriasis.

Oral microbiota diversity in moderate to severe plaque psoriasis, nail psoriasis and psoriatic arthritis

Gaining a comprehensive understanding of the role played by the oral microbiome in moderate to severe plaque psoriasis and its potential implications for disease management and development holds significant importance. With the objective of exploring correlations between the oral microbiota and severe psoriasis, this study involved 72 severe psoriasis patients and 16 healthy individuals, whose clinical manifestations and living habits were carefully recorded. Cutting-edge techniques such as 16S rRNA gene sequencing and bioinformatics analysis were employed to compare the microbial flora, investigating dynamic changes among severe plaque psoriasis patients, psoriatic arthritis patients and healthy individuals. The findings revealed noteworthy patterns including increased levels of Aggregatibacter in the psoriatic arthritis group, accompanied by a decrease in the level of Prevotella. Moreover, the enrichment o Capnocytandophaga (P = 0.009), Campylobacter (P = 0.0022), and Acetobacter (P = 0.0292) was notably more substantial in the psoriasis group compared to the control group, whereas certain bacterial species such as Bacteroides (P = 0.0049), Muribaculaceae (P = 0.0048) demonstrated decreased enrichment. Additionally, the psoriatic arthritis group exhibited significantly higher levels of Ralstonia, Bifidobacterium and Micromonospora. Based on these findings, it can be inferred that individuals with lower levels of Prevotella and higher levels of Corynebacterium may be more susceptible to psoriasis exacerbation.

Prediction of delayed graft function by early salivary microbiota following kidney transplantation

Delayed graft function (DGF) is a frequently observed complication following kidney transplantation (KT). Our prior research revealed dynamic shifts in salivary microbiota post-KT with immediate graft function (IGF), yet its behavior during DGF remains unexplored. Five recipients with DGF and 35 recipients with IGF were enrolled. Saliva samples were collected during the perioperative period, and 16S rRNA gene sequencing was performed. The salivary microbiota of IGFs changed significantly and gradually stabilized with the recovery of renal function. The salivary microbiota composition of DGFs was significantly different from that of IGFs, although the trend of variation appeared to be similar to that of IGFs. Salivary microbiota that differed significantly between patients with DGF and IGF at 1 day after transplantation were able to accurately distinguish the two groups in the randomForest algorithm (accuracy = 0.8333, sensitivity = 0.7778, specificity = 1, and area under curve = 0.85), with Selenomonas playing an important role. Bacteroidales (Spearman's r =  - 0.4872 and p = 0.0293) and Veillonella (Spearmen's r =  - 0.5474 and p = 0.0125) were significantly associated with the serum creatinine in DGF patients. Moreover, the significant differences in overall salivary microbiota structure between DGF and IGF patients disappeared upon long-term follow-up. This is the first study to investigate the dynamic changes in salivary microbiota in DGFs. Our findings suggested that salivary microbiota was able to predict DGF in the early stages after kidney transplantation, which might help the perioperative clinical management and early-stage intervention of kidney transplant recipients. KEY POINTS: • Salivary microbiota on the first day after KT could predict DGF. • Alterations in salivary taxa after KT are related to recovery of renal function.

Etiopathogenesis of Psoriasis: Integration of Proposed Theories

Psoriasis is a chronic inflammatory disease characterized by squamous and erythematous plaques on the skin and the involvement of the immune system. Global prevalence for psoriasis has been reported around 1-3% with a higher incidence in adults and similar proportions between men and women. The risk factors associated with psoriasis are both extrinsic and intrinsic, out of which a polygenic predisposition is a highlight out of the latter. Psoriasis etiology is not yet fully described, but several hypothesis have been proposed: 1) the autoimmunity hypothesis is based on the over-expression of antimicrobial peptides such as LL-37, the proteins ADAMTSL5, K17, and hsp27, or lipids synthesized by the PLA2G4D enzyme, all of which may serve as autoantigens to promote the differentiation of autoreactive lymphocytes T and unleash a chronic inflammatory response; 2) dysbiosis of skin microbiota hypothesis in psoriasis has gained relevance due to the observations of a loss of diversity and the participation of pathogenic bacteria such as Streptococcus spp. or Staphylococcus spp. the fungi Malassezia spp. or Candida spp. and the virus HPV, HCV, or HIV in psoriatic plaques; 3) the oxidative stress hypothesis, the most recent one, describes that the cell injury and the release of proinflammatory mediators and antimicrobial peptides that leads to activate of the Th1/Th17 axis observed in psoriasis is caused by a higher release of reactive oxygen species and the imbalance between oxidant and antioxidant mechanisms. This review aims to describe the mechanisms involved in the three hypotheses on the etiopathogeneses of psoriasis.

The salivary microbiota is altered in cervical dysplasia patients and influenced by conization

This study supports the correlation between the salivary microbiota and cervical dysplasia and suggests that smoking influences the salivary microbiota.

Unexpected lower level of oral periodontal pathogens in patients with high numbers of systemic diseases

Background

Periodontal disease is associated with systemic conditions such as diabetes, arthritis, and cardiovascular disease, all diseases with large inflammatory components. Some, but not all, reports show periopathogens Porphyromonas gingivialis and Tannerella forsythia at higher levels orally in people with one of these chronic diseases and in people with more severe cases. These oral pathogens are thought to be positively associated with systemic inflammatory diseases through induction of oral inflammation that works to distort systemic inflammation or by directly inducing inflammation at distal sites in the body. This study aimed to determine if, among patients with severe periodontal disease, those with multi-morbidity (or many chronic diseases) showed higher levels of periodontal pathogens.

Methods

A total of 201 adult subjects, including 84 with severe periodontal disease were recruited between 1/2017 and 6/2019 at a city dental clinic. Electronic charts supplied self-reported diseases and conditions which informed a morbidity index based on the number of chronic diseases and conditions present. Salivary composition was determined by 16S rRNA gene sequencing.

Results

As expected, patients with severe periodontal disease showed higher levels of periodontal pathogens in their saliva. Also, those with severe periodontal disease showed higher levels of multiple chronic diseases (multimorbidity). An examination of the 84 patients with severe periodontal disease revealed some subjects despite being of advanced age were free or nearly free of systemic disease. Surprisingly, the salivary microbiota of the least healthy of these 84 subjects, defined here as those with maximal multimorbidity, showed significantly lower relative numbers of periodontal pathogens, including Porphyromonas gingivalis and Tannerella Forsythia, after controlling for active caries, tobacco usage, age, and gender. Analysis of a control group with none to moderate periodontal disease revealed no association of multimorbidity or numbers of medications used and specific oral bacteria, indicating the importance of severe periodontal disease as a variable of interest.

Conclusion

The hypothesis that periodontal disease patients with higher levels of multimorbidity would have higher levels of oral periodontal pathogens is false. Multimorbidity is associated with a reduced relative number of periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia.

Association Between Salivary Cytokines, Chemokines and Growth Factors and Salivary Gland Function in Children with Chronic Kidney Disease

Introduction

Chronic kidney disease (CKD) is a systemic inflammatory disease that leads to multiple organ complications not only in the kidneys and the cardiovascular system, but also in the oral cavity. CKD children experience reduced saliva secretion (hyposalivation), which leads to increased incidence of dental caries and significant impairment of patients' quality of life. However, the causes of salivary gland dysfunction in children with CKD are unknown. The present study is the first to evaluate the inflammatory and anti-inflammatory profile in the saliva of children with CKD at different stages of renal failure with normal and reduced salivary gland function.

Methods

Thirty children with CKD (age 9-16) and thirty age- and gender-matched healthy children were classified for the study. Salivary inflammatory and anti-inflammatory profile were assayed using the multiplex ELISA assay.

Results

We demonstrated statistically significant changes in salivary pro-inflammatory (↑TNF-α, ↓IL-7), anti-inflammatory (↑IL-10), Th1 (↑INF-γ, ↑IL-15), Th2 (↑IL-4, ↑IL-5, ↑IL-6, ↑IL-9) and Th17 (IL-17) cytokines as well as chemokines (↑MCP-1/CCL-2, ↑MIP-1α/CCL3, ↓MIP-1β/CCL4, ↓EOTAXIN/CCL11) and growth factors (↑G-CSF, ↑FGF) in unstimulated saliva of children with CKD compared to the controls. Although the evaluation of the salivary inflammatory profile does not indicate a particular dominance of any of the branches of the immune system, we observed a statistically significant increase in the concentration of all Th2 cytokines assayed. The multivariate regression analysis showed that the content of salivary cytokines, chemokines and growth factors depends on the secretory function of the salivary glands, ie, salivary flow, total protein concentration and amylase activity in the saliva. Salivary MIP-1α/CCL3 was the most effective to differentiate children with CKD and hyposalivation from patients with normal saliva secretion.

Discussion

Inflammation is involved in salivary gland dysfunction in children with CKD, although further studies on in vitro and in vivo models are necessary to confirm this hypothesis.

The link between total antioxidant status, total oxidant status, arylesterase activity, and subgingival microbiota in psoriasis patients

BACKGROUND

Studies focusing on the relationship between periodontitis and systemic diseases have suggested a possible association between these two chronic and inflammatory disorders. We aimed to comparatively investigate the salivary oxidative status, biomarker levels, clinical findings, and the microbial load on subgingival biofilm samples in psoriasis patients and controls.

METHODS

Forty participants were allocated into four groups as follows: (1) systemically and periodontally healthy (C group); (2) systemically healthy with periodontitis (P group); (3) psoriasis (Ps) and periodontally healthy (Ps-C group); and (4) Ps with periodontitis (Ps-P group). Subgingival biofilm samples were obtained to detect the periodontopathogenic agents by Real-time PCR (qPCR). The total antioxidant status (TAS) (mmol/l), total oxidant status (TOS) (μmol/l), and arylesterase (ARE) activity (U/L) were analyzed using saliva samples.

RESULTS

The level of TOS and oxidative stress index (OSI) were significantly higher in patients with Ps-P and P compared to controls (P = 0.001, and P ˂ 0.001, respectively). ARE levels were higher in controls compared to Ps and P (P ˂ 0.001). The prevalences of bacteria detected in subgingival biofilm samples were similar between all groups (P > 0.05).

CONCLUSIONS

This study reported that psoriasis may amplify TOS and OSI, and the co-existence of psoriasis and periodontitis may aggravate oxidative stress.

Oral changes in patients with psoriasis

Psoriasis is one of the most frequent skin diseases. The cause of psoriasis is not fully expained as there are many factors (infectious, traumatic, hormonal, and chemical) that may play a role in the manifestation of its symptoms. One of the factors that may contribute to the appearance of psoriatic lesions may be the lesions in the oral cavity. The occurrence of lesions in the oral cavity is defined as rare, what can be explained by their nonspecific clinical image, and also by the possibility of being overlooked. Most characteristic symptoms of psoriasis occurring in the oral cavity are the geographic tongue and fissured tongue. It is also believed that there is a correlation between psoriasis and oral health- the periodontal and teeth condition as well as changes in saliva secretion. The psoriasis arthritis changes can also affect temporomandibular joint and impair the function of stomatognathic system. Because of these reports, cooperation of dermatologists and dentists in psoriasis care seems to be necessary.

Biomarkers in Oral Fluids as Diagnostic Tool for Psoriasis

Psoriasis is a prevalent worldwide chronic immuno-inflammatory skin disease with various variants and atypical cases. The use of biomarkers for the diagnosis of psoriasis can favor timely treatment and thus improve the quality of life of those affected. In general, the search for biomarkers in oral fluids is recommended as it is a non-invasive and fast technique. This narrative review aimed to identify biomarkers in gingival crevicular fluid (GCF) and saliva to diagnose psoriasis. To achieve this goal, we selected the available literature using the following MESH terms: “psoriasis”, “saliva” and “gingival crevicular fluid”. The studies analyzed for this review cover original research articles available in English. We found three full articles available for psoriasis biomarkers in GCF and ten articles available for psoriasis biomarkers in saliva. Studies showed that in the saliva of healthy individuals and those with psoriasis, there were differences in the levels of inflammatory cytokines, immunoglobulin A, and antioxidant biomarkers. In GCF, individuals with psoriasis showed higher levels of S100A8, IL-18 and sE-selectin in comparison to healthy individuals, independent of periodontal status. Despite these findings, more studies are required to determine an adequate panel of biomarkers to use in saliva or GCF for psoriasis.

Psoriasis between Autoimmunity and Oxidative Stress: Changes Induced by Different Therapeutic Approaches

Psoriasis is defined as chronic, immune-mediated disease. Regardless of the development of new therapeutic approaches, the precise etiology of psoriasis remains unknown and speculative. The aim of this review was to systematize the results of previous research on the role of oxidative stress and aberrant immune response in the pathogenesis of psoriasis, as well as the impact of certain therapeutic modalities on the oxidative status in patients with psoriasis. Complex immune pathways of both the innate and adaptive immune systems appear to be major pathomechanisms in the development of psoriasis. Oxidative stress represents another important contributor to the pathophysiology of disease, and the redox imbalance in psoriasis has been reported in skin cells and, systemically, in plasma and blood cells, and more recently, also in saliva. Current immune model of psoriasis begins with activation of immune system in susceptible person by some environmental factor and loss of immune tolerance to psoriasis autoantigens. Increased production of IL-17 appears to be the most prominent role in psoriasis pathogenesis, while IL-23 is recognized as master regulator in psoriasis having a specific role in cross bridging the production of IL-17 by innate and acquired immunity. Other proinflammatory cytokines, including IFN-γ, TNF-α, IL-1β, IL-6, IL-22, IL-26, IL-29, or IL-36, have also been reported to play important roles in the development of psoriasis. Oxidative stress can promote inflammation through several signaling pathways. The most noticeable and most powerful antioxidative effects exert various biologics compared to more convenient therapeutic modalities, such as methotrexate or phototherapy. The complex interaction of redox, immune, and inflammatory signaling pathways should be focused on further researches tackling the pathophysiology of psoriasis, while antioxidative supplementation could be the solution in some refractory cases of the disease.

Lipocalin 2 Participates in the Epidermal Differentiation and Inflammatory Processes of Psoriasis

As a multifunctional cytokine, lipocalin 2 is weakly expressed in skin and serum under normal conditions. However, it is over-expressed by neutrophils and keratinocytes in the skin lesions and sera in several skin diseases. Recent studies demonstrated that lipocalin 2 participates in the pathogenesis of psoriasis by exerting versatile effects on skin resident cells and infiltrating immune cells. Lipocalin 2 inhibits the synthesis of keratin, involucrin, and loricrin in keratinocytes, leading to epidermal parakeratosis via the Tcf7l1-lipocalin 2 signaling axis. It also recruits inflammatory cells such as T cells and neutrophils into skin lesions via the IL-23/IL17, p38-MAPK, and ERK-1/2 signaling pathways. Additionally, lipocalin 2 and other cytokines such as IL-17 have the synergetic effects on skin cells. The neutralization of lipocalin 2 or relevant cytokines can alleviate psoriasis, verifying that lipocalin 2 is an effective interfering target for psoriasis. In this review, we summarize the roles of lipocalin 2 in the processes of psoriatic inflammation and the promising therapeutic strategies based on lipocalin 2-related molecules.

The Crossroads of Periodontitis and Oral Squamous Cell Carcinoma: Immune Implications and Tumor Promoting Capacities

Periodontitis (PD) is increasingly considered to interact with and promote a number of inflammatory diseases, including cancer. In the case of oral squamous cell carcinoma (OSCC) the local inflammatory response associated with PD is capable of triggering altered cellular events that can promote cancer cell invasion and proliferation of existing primary oral carcinomas as well as supporting the seeding of metastatic tumor cells into the gingival tissue giving rise to secondary tumors. Both the immune and stromal components of the periodontium exhibit phenotypic alterations and functional differences during PD that result in a microenvironment that favors cancer progression. The inflammatory milieu in PD is ideal for cancer cell seeding, migration, proliferation and immune escape. Understanding the interactions governing this attenuated anti-tumor immune response is vital to unveil unexplored preventive or therapeutic possibilities. Here we review the many commonalities between the oral-inflammatory microenvironment in PD and oral-inflammatory responses that are associated with OSCC progression, and how these conditions can act to promote and sustain the hallmarks of cancer.

Periodontitis in patients with psoriasis: A systematic review and meta-analysis

OBJECTIVE

The present study aimed to summarize and update the evidence regarding the association between periodontitis and psoriasis.

METHODS

The present systematic review was conducted under the guidelines of Transparent Reporting of Systematic Reviews and Meta-Analyses (PRISMA) and was recorded in the PROSPERO database, under registration number CRD42017063799. Three databases (MEDLINE, Embase, and Cochrane Library) were searched up to March 2020. Case-control or cohort studies assessing the association between periodontitis and psoriasis were identified. Quantitative synthesis was conducted with meta-analysis.

RESULTS

A total of 13 studies (11 case-control and two cohort studies) assessing the association between periodontitis and psoriasis were included. Of these 13 articles, 9 showed the prevalence of periodontitis or psoriasis. Therefore, meta-analyses were conducted with data retrieved from the nine studies included. Pooled effect estimate for nine studies showed that patients with periodontitis associated with a higher risk of psoriasis with a pooled OR of 2.87 (95% CI, 1.75-4.69).

CONCLUSIONS

This systematic review demonstrated a positive association between periodontitis and psoriasis; however, a causal relationship cannot be established. Due to the weak evidence, caution should be taken when interpreting the results regarding periodontal parameters. Well-designed prospective studies are necessary to evaluate interactions between both diseases.

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.

Impact of Probiotics on the Salivary Microbiota and Salivary Levels of Inflammation-Related Proteins during Short-Term Sugar Stress: A Randomized Controlled Trial

Background: The purpose of the present investigation was to characterize the effect of probiotics on the composition of the salivary microbiota and salivary levels of inflammation-related proteins during short-term sugar stress. We tested the hypotheses that consumption of probiotics may partly counteract the detrimental influence of sugar stress on oral homeostasis. Methods: The present study was a five-week, blinded, randomized controlled trial with four study arms—A: sucrose and probiotic (n = 20); B: sucrose and placebo (n = 20); C: xylitol and probiotic (n = 20); D: xylitol and placebo (n = 20). Saliva samples were collected at baseline and after two and five weeks. The salivary microbiota was characterized by means of 16S rDNA sequencing, and sequences were referenced against the Human Oral Microbiome Database (HOMD). Neutrophil gelatinase-associated lipocalin (NGAL) and transferrin levels were quantified using immunoassays. Results: Sugar stress induced a significant increase in the relative abundance of the genus Streptococcus from 29.8% at baseline to 42.9% after two weeks. Changes were transient and were completely reversed three weeks after discontinuation of sugar stress. Xylitol and probiotics alone had no effect on the salivary microbiota, whereas the combination of xylitol and probiotics induced a significant decrease in the relative abundance of Streptococcus species from 37.6% at baseline to 23.0% at week 2. Sugar stress significantly increased salivary transferrin levels, and the effect was partly counteracted by concomitant use of probiotics. Conclusions: The data clearly demonstrate an impact of combined consumption of xylitol and probiotics on the composition of the salivary microbiota. Future studies are needed to evaluate whether the combined use of xylitol and the probiotic strains tested could have clinically protective effects during periods of sugar stress.

The possible role of oral microbiome in autoimmunity

OBJECTIVE

The human microbiome refers to the entire habitat, including microorganisms, their genomes and the surrounding environmental conditions of the microbial ecosystem. When the equilibrium between microbial habitats and host is disturbed, dysbiosis is caused. The oral microbiome (OMB) has been implicated in the manifestation of many intra- and extraoral diseases. Lately, there has been an intense effort to investigate and specify the relationship between microbial complexes, especially that of the oral cavity and intestine and autoimmunity. This study aimed to review the current literature about the possible role of the OMB in the pathogenesis of autoimmune diseases.

METHODS

We searched for published articles in English indexed in PubMed, Medline, Research Gate and Google Scholar using a search strategy that included terms for oral microbiome, autoimmune diseases, dysbiosis and next-generation sequencing.

RESULTS

An important number of articles were gathered and used for the description of the possible impact of dysbiosis of OMB in the pathogenesis of Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, Behcet's disease, Crohn's disease and psoriasis.

CONCLUSION

This review article draws attention to the relationship between OMB and the triggering of a number of autoimmune diseases. Although this specific topic has been previously reviewed, herein, the authors review recent literature regarding the full list of nosological entities related to the OMB, point out the interaction between the microbiome and sex hormones with regard to their role in autoimmunity and discuss novel and promising therapeutic approaches for systemic autoimmune diseases. Furthermore, the question arises of whether the OMB is associated with oral bullous autoimmune diseases.

Neutrophil gelatinase associated lipocalin a biomarker for bacterial-induced pharyngeal infection-A pilot study

OBJECTIVES

Neutrophil gelatinase associated lipocalin (NGAL) is secreted from activated neutrophil granulocytes and is considered an acute phase protein. The aim of this pilot study was to determine whether the NGAL concentration in saliva increases in response to a bacterial throat infection and identify pitfalls, which shall be taken into account in a protocol in a larger hypothesis testing study.

METHODS

Saliva samples for measurement of NGAL concentration where obtained from cases with an acute throat infection (n = 21) and controls (n = 24). Among cases, plasma NGAL, plasma CRP, and whole blood leukocytes, were measured as well.

RESULTS

There was no significant difference in NGAL saliva concentration between cases and controls overall (p = .31). For both cases and controls, the saliva NGAL concentration decreased significantly after cleansing the mouth with tap water (cases p = .01; controls p = .01). Among cases, a significant positive correlation between saliva NGAL concentrations before mouth cleansing and plasma CRP concentrations (p = .001) was observed. Blood neutrophil granulocyte count presented a nonsignificant positive correlation to saliva NGAL (p = .07).

CONCLUSION

We could not demonstrate a simple association between the salivary NGAL concentration and pharyngeal bacterial infection. Furthermore, the salivary NGAL concentrations were higher among some controls than cases, suggesting that cofounders for example, periodontitis, uneven salivary dilution level, or other exogenous factors affect salivary NGAL content.

Salivary microbiota and inflammation-related proteins in patients with psoriasis

Objective

The purpose of the present study was to characterize the composition of the salivary microbiota and quantify salivary levels of inflammation‐related proteins (neutrophil gelatinase‐associated lipocalin [NGAL] and transferrin) in patients with psoriasis and compare data to those obtained in patients with periodontitis and orally healthy controls, respectively.

Materials and methods

Stimulated saliva samples from patients with psoriasis (n = 27), patients with periodontitis (n = 58), and orally healthy controls (n = 52) were characterized by means of next‐generation sequencing of the 16S rRNA gene. Salivary levels of NGAL and transferrin were quantified using immunoassays.

Results

Linear discriminant effect size analysis showed that 52 (22 psoriasis‐associated and 30 periodontitis‐associated) and 21 (8 psoriasis‐associated and 13 orally healthy control‐associated) bacterial taxa differentiated the salivary microbiota in patients with psoriasis from that of patients with periodontitis and orally healthy controls, respectively. Significantly lower mean salivary levels of NGAL (psoriasis: 996 [std. error 320], periodontitis: 2,072 [295], orally healthy controls: 2,551 [345] ng/ml, p < .0001) and transferrin (psoriasis: 4.37 [0.92], periodontitis: 7.25 [0.88], orally healthy controls: 10.02 [0.94] ng/ml, p < .0001) were identified in patients with psoriasis.

Conclusions

Psoriasis associates with characteristics of the salivary microbiota and salivary levels of inflammation‐related proteins, which are different from characteristics in patients with periodontitis and orally healthy controls, respectively.