Saliva in the diagnosis of diseases

Polymicrobial detection and salivary metabolomics of children with early childhood caries

Background

Early childhood caries (ECC) has been proposed to be associated with various microorganisms and metabolites. This study aims to compare the prevalence of specific microbial species and salivary metabolomics profile in children with and without ECC, and to explore the correlation between salivary metabolites and targeted microbes.

Method

Five ml of unstimulated saliva was collected from 32 ECC and 22 caries-free children. Clinical indexed were recorded and questionnaires regarding oral health and dietary habits were obtained from the guardians. The presence of eight specific microbial species were examined using species-specific quantitative PCR (qPCR). Untargeted metabolomics was analyzed to identify key differential metabolites and pathways. Correlations among clinical, microbial, and metabolomic data were further explored.

Results

The prevalence of Scardovia wiggsiae (90.6%, P < 0.001), Streptococcus mutans (43.8%, P = 0.006), Streptococcus sobrinus (62.5%, P < 0.001), Ligilactobacillus salivarius (93.6%, P = 0.01) and Candida albicans (56.3%, P < 0.001) were significantly higher in the ECC group. The prevalence of ECC was higher in children with two targeted species present compared with children with one targeted species. Histidine metabolism and branched-chain amino acids degradation were activated in ECC group, while glyoxylate and dicarboxylate metabolism, purine and pyrimidine metabolism were inhibited. Histidine and glutathione metabolism was activated with enrichment of targeted microbial species, while linoleic acid metabolism and biotin metabolism was inhibited. The duration of each toothbrushing was a significant risk factor for ECC experience.

Conclusion

The prevalence of Scardovia wiggsiae, Streptococcus mutans, Streptococcus sobrinus and Candida albicans is higher in ECC children compared to caries-free children. Oral habits and salivary metabolites also vary between ECC and caries-free children.

Identification of Salivary Biomarkers in Colorectal Cancer by Integrating Olink Proteomics and Metabolomics

Identifying novel biomarkers is crucial for early detection of colorectal cancer (CRC). Saliva, as a noninvasive sample, holds promise for CRC detection. Here, we used Olink proteomics and untargeted metabolomics to analyze saliva samples from CRC patients and healthy controls with the aim of identifying candidate biomarkers in CRC saliva. Univariate and multivariate analyses revealed 16 differentially expressed proteins (DEPs) and 40 differentially accumulated metabolites (DAMs). Pathway enrichment showed DEPs were mainly involved in cancer transcriptional dysregulation, Toll-like receptor signaling, and chemokine signaling. Metabolomics analysis highlighted significant changes in amino acid metabolites, particularly in pathways such as arginine biosynthesis, histidine metabolism, and cysteine and methionine metabolism. Random forest analysis and ELISA validation identified four potential biomarkers: succinate, l-methionine, GZMB, and MMP12. A combined protein-metabolite diagnostic model was developed using logistic regression, achieving an area under the curve of 0.933 (95% CI: 0.871-0.996) for the discovery cohort and 0.969 (95% CI: 0.918-1.000) for the validation cohort, effectively distinguishing CRC patients from healthy individuals. In conclusion, our study identified and validated a panel of noninvasive saliva-based biomarkers that could improve CRC screening and provide new insights into clinical CRC diagnosis.

Prospecting salivary tau as a diagnostic for Alzheimer's type dementia

Although recognized as one of the most critical and prevalent dementias, Alzheimer's disease (AD) still does not have an affirmative biological marker, being diagnosed by excluding other pathologies that present similar symptoms. In the last decade, advances have been made in researching pathophysiological phenomena related to AD, with the identification of probable biomarkers. Some of these substances have a direct action on the degenerative activity that involves AD and may be associated with other pathological processes, such as inflammation and diabetes.

Objective

These occurrences led us to investigate further whether the levels of certain substances may be associated with the onset and progression of Alzheimer's disease. Biomarkers can be found in plasma, saliva and cerebrospinal fluid.

Methods

This project investigated tau protein as a possible salivary biomarker in 76 patients, control group and Alzheimer's, with different age groups, to establish a positive correlation between the studied biomarker and AD.

Results

Our findings showed that phosphorylated tau (pTAU) concentrations are higher in AD patients and somewhat lower in elderly patients without Alzheimer's, but in young patients without Alzheimer's the levels are much lower. Total tau had very similar levels in three groups evaluated.

Conclusions

Based on these results, we believe in the possibility of using saliva as an auxiliary method in diagnosing Alzheimer's disease, with the advantages of low cost, non-invasiveness, and ease of collection. Still, more investigations will be needed to confirm this method presented.

Mucosal Wetness, Hyposalivation, and Local Defense in Periodontal Inflammation

OBJECTIVE

To evaluate the potential relationship between local salivary coating of mucosal surfaces, clinical periodontal status, hyposalivation, and local inflammatory response with a specific reference for MUC4 and TNF-α levels.

MATERIALS AND METHODS

Based on their salivary flow rates, 24 hyposalivators and 26 normosalivators were recruited. Mucosal wetness (MW) and mucosal surface pH values were determined. Clinical periodontal parameters were recorded and gingival crevicular fluid (GCF) samples were obtained. Mucin 4 (MUC4) and TNF-α levels in local and whole salivary and GCF samples were determined with ELISA kits.

RESULTS

GI and BoP were significantly higher in the hyposalivation group, while MW and mucosal pH values were significantly lower in hyposalivators, except for the labial surface. MUC4 and TNF-α levels showed significant differences among the groups. In the anterior region, GCF TNF-α concentration was high in hyposalivation patients; in the molar region, GCF MUC4 was significantly higher in normosalivators.

CONCLUSIONS

Based on the differences which MW presented at local sites, MW may be utilized as a possible practical tool to reveal the local salivary characteristics in various clinical periodontal conditions based on the presence/extent of local inflammatory response, which may be important when the site-specific nature of periodontal diseases is concerned.

Global Research Trends in the Detection and Diagnosis of Dental Caries: A Bibliometric Analysis

This study aims to provide an overview of the global research trends in the detection and diagnosis of dental caries in the past 20 years. A literature search was conducted in the Scopus Database to retrieve studies on the diagnostic approaches for dental caries published from January 2003 to December 2023. The diagnostic approaches in the retrieved studies were examined and the studies were categorized according to the diagnostic approaches investigated. Bibliometric data including journals, countries, affiliations, authors, and numbers of citations of the publications were summarised. The publications' keyword co-occurrence was analysed using VOSviewer. This bibliometric analysis included 1879 publications investigating seven categories of caries diagnostic approaches, including visual and/or tactile (n = 459; 19%), radiation-based (n = 662; 27%), light-based (n = 771; 32%), ultrasound-based (n = 28; 1%), electric-based (n = 51; 2%), molecular-based (n = 196; 8%) diagnostic approaches, as well as AI-based diagnostic interpretation aids (n = 265; 11%). An increase in the annual number of publications on caries diagnostic approaches was observed in the past 20 years. Caries Research (n = 103) presented the highest number of publications on caries diagnostic approaches. The country with the highest number of publications was the United States (n = 1092). The University of São Paulo was the institution that published the highest number of articles (n = 195). The publication with the highest citation has been cited 932 times. VOS viewer revealed that the most frequently occurring keywords were 'Deep Learning', 'Artificial Intelligence', 'Laser Fluorescence' and 'Radiography'. This bibliometric analysis highlighted an emerging global research trend in the detection and diagnosis approaches for dental caries in the past 20 years. An evident increase in publications on molecular-based caries diagnostic approaches and AI-based diagnostic interpretation aids was perceived over the last 5 years.

Associations between salivary microbiota and Kaposi's sarcoma-associated herpesvirus infection in people with HIV

OBJECTIVE

Kaposi's sarcoma-associated herpesvirus (KSHV) infection, essential for Kaposi sarcoma development especially in people with HIV (PWH), has been proposed to be transmitted through saliva. The potential role of salivary microbiota played in the infection of KSHV is largely obscure. This study aimed to explore the association between salivary microbiota and KSHV infection among PWH.

DESIGN

Cross-sectional study.

METHODS

During May to December 2022, we conducted a cross-sectional study among PWH in Ili prefecture Xinjiang, China. Participants completed face-to-face questionnaires, plasma and saliva samples were collected to assay KSHV infection status and 16S rRNA sequencing. We distinguished demographic characteristics between groups with and without KSHV, and compared the α and β diversity of the salivary microbiota. LEfSe identified key bacterial genera for Random Forest and XGBoost models to recognize the important discriminatory features.

RESULTS

Among 876 PWH in Xinjiang, 38.7% were KSHV seropositive. Regression models indicated that moderate drinking, absence of dental treatment history, higher CD4 counts, and higher CD4/CD8 ratios were negatively associated with KSHV seropositivity. Linear discriminant analysis effect size (LEfSe) analysis demonstrated that 14 bacterial genera were significantly enriched at the genus level in the group with or without KSHV. Machine learning analyses gave an AUC of 0.66 for Random Forest and 0.85 for XGBoost in predicting KSHV infection status. The bacterial genera, including Alloprevotella , Fusobacterium , Prevotella_7 , Porphyromonas , Rothia , and Leptotrichia , were identified as important discriminatory features.

CONCLUSION

This study suggests the potential role of salivary microbiota in KSHV transmission among PWH. Identified microbial genera offer promising biomarkers for monitoring and managing KSHV in PWH.

Analyses of Saliva Metabolome Reveal Patterns of Metabolites That Differentiate SARS-CoV-2 Infection and COVID-19 Disease Severity

BACKGROUND

The metabolome of COVID-19 patients has been studied sparsely, with most research focusing on a limited number of plasma metabolites or small cohorts. This is the first study to test saliva metabolites in COVID-19 patients in a comprehensive way, revealing patterns significantly linked to disease and severity, highlighting saliva's potential as a non-invasive tool for pathogenesis or diagnostic studies.

METHODS

We included 30 asymptomatic subjects with no prior COVID-19 infection or vaccination, 102 patients with mild SARS-CoV-2 infection, and 61 hospitalized patients with confirmed SARS-CoV-2 status. Saliva samples were analyzed using hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS/MS) in positive and negative ionization modes.

RESULTS

Significant differences in metabolites were identified in COVID-19 patients, with distinct patterns associated with disease severity. Dipeptides such as Val-Glu and Met-Gln were highly elevated in moderate cases, suggesting specific protease activity related to SARS-CoV-2. Acetylated amino acids like N-acetylserine and N-acetylhistidine increased in severe cases. Bacterial metabolites, including muramic acid and indole-3-carboxaldehyde, were higher in mild-moderate cases, indicating that oral microbiota differs according to disease severity. In severe cases, polyamines and organ-damage-related metabolites, such as N-acetylspermine and 3-methylcytidine, were significantly increased. Interestingly, most metabolites that were reduced in moderate cases were elevated in severe cases.

CONCLUSIONS

Saliva metabolomics offers insightful information that is potentially useful in studying COVID-19 severity and for diagnosis.

Aptamers in dentistry: diagnosis, therapeutics, and future perspectives

Oral health is essential to general health. The diagnosis of dental diseases and treatment planning of dental care need to be straightforward and accurate. Recent studies have reported the use of aptamers in dentistry to achieve a simple diagnosis and facilitate therapy. Aptamers comprise nucleic acid sequences that possess a strong affinity for their target. Synthesized chemically, aptamers have several advantages, including smaller size, higher stability, and lower immunogenicity compared with monoclonal antibodies. They can be used to detect biomarkers in saliva and the presence of various pathogens, or can be used as a targeted drug delivery system for disease treatment. This review highlights current research on aptamers for dental care, especially the recent progress in oral disease diagnosis and therapeutics. The challenges and unresolved problems faced by the clinical use of aptamers are also discussed. In the future, the clinical applications of aptamers will be further extended to include, for example, dental indications and regenerative dentistry.

Salivary Extracellular Vesicles in Detection of Cancers Other than Head and Neck: A Systematic Review

Cancer is one of the leading causes of death worldwide. Evidence indicates that extracellular vesicles are involved in cancer development and may be used as promising biomarkers in cancer detection. Concomitantly, saliva constitutes a non-invasive and inexpensive source of biomarkers. This systematic review investigates the use of salivary extracellular vesicles in detecting cancers located outside of the head and neck. PubMed, Web of Science, Scopus, and Embase were thoroughly searched from database inception to 16 July 2024. Data from sixteen eligible studies were analyzed, including glioblastoma, lung, esophageal, gastric, prostate, hepatocellular, breast, and pancreatobiliary tract cancers. The findings highlight strong diagnostic potential for lung and esophageal cancers, where specific exosomal RNAs and proteins demonstrated high accuracy in distinguishing cancer patients from healthy individuals. Additionally, biomarkers in glioblastoma showed prognostic value, while those in hepatocellular and pancreatobiliary cancers exhibited potential for early detection. However, gastric and prostate cancer biomarkers showed limited reliability, and breast cancer biomarkers require further validation. In conclusion, salivary extracellular vesicles present potential in non-invasive detection across multiple cancer types; however, their diagnostic power needs further research, including standardization and large-scale validation.

Urine-based ELISA using a recombinant chimeric protein for the diagnosis of paucibacillary and multibacillary leprosy

Leprosy diagnosis is difficult to perform due to variable sensitivity and/or specificity of the tests. In addition, the collection of the blood samples requires laboratorial structure and trained professionals. In the present study, the diagnostic efficacy of M1 chimeric protein, which was recently showed to be antigenic for leprosy using a serum-based ELISA, was evaluated against patient urine. Paired serum and urine samples were collected from patients with paucibacillary (PB) and multibacillary (MB) leprosy, tegumentary and visceral leishmaniasis, tuberculosis, Chagas disease, malaria, and HIV-infected subjects. Samples from healthy individuals and household contacts were also used. The protein and peptides used to compose it were used as antigens, and results showed that the four peptides presented good sensitivity and specificity to detect MB leprosy, while M1 protein showed sensitivity and specificity of 98.5 % and 100 %, respectively, to detect both PB and MB leprosy, when an urine-based ELISA was performed. Positive (PPV) and negative (NPV) predictive values were 100 % and 98.3 %, respectively. In a serum-based ELISA, sensitivity and specificity were 96.9 % and 100 %, respectively, with PPV and NPV of 100 % and 96.5 %, respectively. In conclusion, preliminary data suggest that M1 protein could be considered for diagnosis of leprosy by using patient urine.

Recent advances in nanoarchitectonics of two-dimensional nanomaterials for dental biosensing and drug delivery

Two-dimensional (2D) nanoarchitectonics involve the creation of functional material assemblies and structures at the nanoscopic level by combining and organizing nanoscale components through various strategies, such as chemical and physical reforming, atomic and molecular manipulation, and self-assembly. Significant advancements have been made in the field, with the goal of producing functional materials from these nanoscale components. 2D nanomaterials, in particular, have gained substantial attention due to their large surface areas which are ideal for numerous surface-active applications. In this review article, nanoarchitectonics of 2D nanomaterials based biomedical applications are discussed. We aim to provide a concise overview of how nanoarchitectonics using 2D nanomaterials can be applied to dental healthcare, with an emphasis on biosensing and drug delivery. By offering a deeper understanding of nanoarchitectonics with programmable structures and predictable properties, we hope to inspire new innovations in the dental bioapplications of 2D nanomaterials.

Research progress on the role of decorin in the development of oral mucosal carcinogenesis

Decorin (DCN) is primarily found in the connective tissues of various parts of the body, including the lungs, kidneys, bone tissue, aorta, and tendons. It is an important component of the extracellular matrix (ECM) and belongs to the class I small leucine-rich proteoglycans family. DCN is increasingly attracting attention due to its significant role in tumors, fibrotic diseases, and the regulation of vascular formation. Moreover, its anti-tumor properties have positioned it as a promising biomarker in the fight against cancer. Numerous studies have confirmed that DCN can exert inhibitory effects in various solid tumors, particularly in oral squamous cell carcinoma (OSCC), by activating its downstream pathways through binding with the epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition (MET) receptor, or by stabilizing and enhancing the expression of the tumor suppressor gene p53 to mediate apoptosis in cancer cells that have undergone mutation. The occurrence of OSCC is a continuous and dynamic process, encompassing the transition from normal mucosa to oral potentially malignant disorders (OPMDs), and further progressing from OPMDs to the malignant transformation into OSCC. We have found that DCN may exhibit a bidirectional effect in the progression of oral mucosal carcinogenesis, showing a trend of initial elevation followed by a decline, which decreases with the differentiation of OSCC. In OPMDs, DCN exhibits high expression and may be associated with malignant transformation, possibly linked to the increased expression of P53 in OPMDs. In OSCC, the expression of DCN is reduced, which can impact OSCC angiogenesis, and inhibit tumor cell proliferation, migration, and invasion capabilities, serving as a potential marker for predicting adverse prognosis in OSCC patients. This article reviews the current research status of DCN, covering its molecular structure, properties, and involvement in the onset and progression of oral mucosal carcinogenesis. It elucidates DCN's role in this process and aims to offer insights for future investigations into its mechanism of action in oral mucosal carcinogenesis and its potential application in the early diagnosis and treatment of OSCC.

Radiation-induced changes in salivary metabolite profile and pathways in head and neck cancer patients

INTRODUCTION

This longitudinal study assessed the salivary metabolic profile in patients with head and neck cancer (HNC) treated with radiotherapy (RT). This study aims to investigate salivary metabolites and biological oral pathways induced by RT.

METHODS

Clinical data and unstimulated whole-mouth saliva (USWMS) were obtained from 45 HNC patients before, during, and one week after the RT. Data was also collected from 30 healthy controls. NMR spectroscopy identified and quantified 24 metabolites. Spearman's rank correlation analysis and pathway enrichment analysis (MetaboAnalyst 6.0) was performed to check the effect of cancer therapy on the correlation and pathways of different salivary metabolites.

RESULTS

Of 24 metabolites identified, 17 salivary metabolites showed a consistent decrease in the concentration during and after treatment of HNC patients. The metabolite proline decreased, whereas fucose and 1,2-Propanediol were increased in the saliva causing altered redox balance and abnormal fucosylation in HNC patients compared to controls. Spearman correlation analysis indicated changes between pyruvate and some other metabolites, including alanine, trimethylamine, choline, taurine, and succinate, during RT. Five pathways (Pyruvate metabolism; Glycolysis / Gluconeogenesis; Glycine, serine, and threonine metabolism; Glyoxylate and dicarboxylate metabolism; and Alanine, aspartate and glutamate metabolism) are affected, demonstrating the metabolic dysregulation due to RT. The pyruvate metabolism was overpresented with the high Pathway Impact score.

CONCLUSION

Salivary metabolomics analysis revealed significant alterations in the metabolic profile of HNC patients undergoing RT, providing valuable insights into treatment-induced oral pathobiological changes. Alterations in salivary pathways during RT suggest disturbances in redox homeostasis, oxidative stress, and inflammation. The ability to monitor salivary metabolites and pathways non-invasively holds promise to personalized medicine in HNC treatment by enabling early detection of treatment-related toxicities, monitoring treatment response, and tailoring interventions to patient needs.

The Global Trends and Advances in Oral Microbiome Research on Oral Squamous Cell Carcinoma: A Systematic Review

The oral microbiome is increasingly recognized as a key factor in the development and progression of oral squamous cell carcinoma (OSCC). Dysbiosis has been associated with inflammation and tumorigenesis, highlighting the potential of microbial alterations and salivary biomarkers as tools for early, non-invasive diagnosis. This review examines recent advancements in understanding the oral microbiome's role in OSCC. A comprehensive synthesis of studies from 2016 to 2024 was conducted to identify emerging themes and significant findings in the field. Key topics included the interplay between microbiome-driven mechanisms and cancer development, with a focus on microbial communities and their metabolic byproducts. The findings emphasize the importance of specific microbial alterations in modulating immune responses and tumor microenvironments, as well as the promise of biomarkers such as interleukins and miRNA signatures in improving diagnostic accuracy. Recent research trends indicate growing interest in the therapeutic potential of targeting the oral microbiome in OSCC management. Despite significant advancements, gaps remain in the understanding of the precise mechanisms linking dysbiosis to cancer progression. This review underscores the need for continued research to develop personalized diagnostic and therapeutic strategies based on the oral microbiome, with the potential to transform OSCC management.

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.

Diagnosis of lung cancer using salivary miRNAs expression and clinical characteristics

OBJECTIVE

Lung cancer (LC), the primary cause for cancer-related death globally is a diverse illness with various characteristics. Saliva is a readily available biofluid and a rich source of miRNA. It can be collected non-invasively as well as transported and stored easily. The process is also reproducible and cost-effective. The aim of this study was to evaluate the salivary expression of microRNAs let-7a-2, miR-221, and miR-20a in saliva and evaluate their efficacy, using multiple logistic regression (MLR) model, in diagnosis of lung cancer.

MATERIALS

Samples of saliva were obtained from 40 lung cancer patients (20 lung adenocarcinoma and 20 lung squamous cell carcinoma) and 20 healthy controls. The levels of let-7a-2, miR-221, and miR-20a expression in saliva were assessed by RT-qPCR. Receiver operating characteristic (ROC) curve was utilized to assess the potential significance of miRNAs in saliva for lung cancer diagnosis with the use of multiple logistic regression (MLR), principal component analysis, and machine learning methods.

RESULTS

Diagnostic odds ratio (DOR) of miR-20a in lung adenocarcinoma diagnosis versus healthy control was higher than miR-221, and DOR of miR-221 was higher than let-7a-2. miR-20a demonstrated a higher DOR for small cell lung carcinoma versus healthy control compared to let-7a-2, which in turn exhibited a higher DOR than miR-221. MLR of miR-221, let-7a-2, miR-20a, and smoking habit using main effects led to accuracy of 0.725 (sensitivity: 0.80, specificity: 0.65) and AUC = 0.795 for differentiation of small-cell lung carcinoma from lung adenocarcinoma. Our results showed that MLR based on salivary miRNAs could diagnose LUAD and SCLC from healthy control using main effects and two-way interactions with the accuracy of 0.90 (sensitivity = 0.95 and specificity = 0.85).

CONCLUSION

A salivary miRNA-based MLR model is a promising diagnostic tool for lung cancer, offering a non-invasive screening option for high-risk asymptomatic individuals.

Detection of Cancer Stem Cells from Patient Samples

The existence of cancer stem cells (CSCs) in various tumors has become increasingly clear in addition to their prominent role in therapy resistance, metastasis, and recurrence. For early diagnosis, disease progression monitoring, and targeting, there is a high demand for clinical-grade methods for quantitative measurement of CSCs from patient samples. Despite years of active research, standard measurement of CSCs has not yet reached clinical settings, especially in the case of solid tumors. This is because detecting this plastic heterogeneous population of cells is not straightforward. This review summarizes various techniques, highlighting their benefits and limitations in detecting CSCs from patient samples. In addition, methods designed to detect CSCs based on secreted and niche-associated signaling factors are reviewed. Spatial and single-cell methods for analyzing patient tumor tissues and noninvasive techniques such as liquid biopsy and in vivo imaging are discussed. Additionally, methods recently established in laboratories, preclinical studies, and clinical assays are covered. Finally, we discuss the characteristics of an ideal method as we look toward the future.

Association of salivary proteins with dental caries in children with mixed dentition: a systematic review

PURPOSE

To review the current evidence on the association between salivary protein profile and dental caries in children during mixed dentition stage.

METHODS

This systematic review followed the PRISMA 2020 guidelines. Searches were run in PubMed, Scopus and Embase along with gray literature. The searches were limited to studies on humans, published from inception to February 2024. Observational studies exploring correlations between salivary proteins and caries in children during mixed dentition (6-13 years) were included. The methodological quality of included studies was analyzed independently by two reviewers using the Joanna Briggs checklist and Newcastle-Ottawa scale, respectively followed by a qualitative synthesis.

RESULTS

A total of 17 primary studies were included. The studies recruited 1,330 subjects including 612 caries-active and 505 caries-free subjects. The total protein content was higher in caries-active subjects. Among the glycoproteins, IgA and MUC5B were higher in caries-free subjects while the levels of MUC7 were lower in the caries-free group. Antimicrobial peptides and proteinase-3 levels were also higher in caries-free subjects. Contradictory findings were reported for the association of α- amylase and carbonic anhydrase with caries status. The included studies were categorized as good quality (n = 4), fair quality (n = 12) and poor quality (n = 1).

CONCLUSION

Based on fair-quality studies included in this review and within its limitations, the findings revealed that salivary proteins may be associated with susceptibility to dental caries in mixed dentition. Total salivary proteins are upregulated in caries-active subjects while salivary IgA, antimicrobial peptides and proteinase-3 are increased in caries-free subjects.

SYSTEMATIC REVIEW REGISTRATION

The study protocol was registered in PROSPERO (registration number CRD42024517374).

Reusable Biosensor for Easy RNA Detection from Unfiltered Saliva

Biosensors are transforming point-of-care diagnostics by simplifying the detection process and enabling rapid, accurate testing. This study introduces a novel, reusable biosensor designed for direct viral RNA detection from unfiltered saliva, targeting SARS-CoV-2. Unlike conventional methods requiring filtration, our biosensor leverages a unique electrode design that prevents interference from saliva debris, allowing precise measurements. The biosensor is based on electrochemical principles, employing oligonucleotide probes immobilized on a hydrophobic-coated electrode, which prevents air bubbles and salt crystal formation. During validation, the biosensor demonstrated a sensitivity and specificity of 100%, accurately identifying SARS-CoV-2 in saliva samples without false positives or negatives. Cross-validation with RT-qPCR, the gold standard for COVID-19 diagnostics, confirmed the reliability of our device. The biosensor's performance was tested on 60 participants, yielding 12 true positive results and 48 true negatives, aligning perfectly with RT-qPCR outcomes. This reusable, easy-to-use biosensor offers significant potential for point-of-care applications in various healthcare settings, providing a fast, efficient, and cost-effective method for detecting viral infections such as COVID-19. Its robust design, minimal sample preparation requirements, and multiple-use capability mark a significant advancement in biosensing technology.

Lipidomics of Huntington's Disease: A Comprehensive Review of Current Status and Future Directions

BACKGROUND

Huntington's disease (HD) is a multifaceted neurological disorder characterized by the progressive deterioration of motor, cognitive, and psychiatric functions. Despite a limited understanding of its pathogenesis, research has implicated abnormal trinucleotide cytosine-adenine-guanine CAG repeat expansion in the huntingtin gene (HTT) as a critical factor. The development of innovative strategies is imperative for the early detection of predictive biomarkers, enabling timely intervention and mitigating irreversible cellular damage. Lipidomics, a comprehensive analytical approach, has emerged as an indispensable tool for systematically characterizing lipid profiles and elucidating their role in disease pathology.

METHOD

A MedLine search was performed to identify studies that use lipidomics for the characterization of HD. Search terms included "Huntington disease"; "lipidomics"; "biomarker discovery"; "NMR"; and "Mass spectrometry".

RESULTS

This review highlights the significance of lipidomics in HD diagnosis and treatment, exploring changes in brain lipids and their functions. Recent breakthroughs in analytical techniques, particularly mass spectrometry and NMR spectroscopy, have revolutionized brain lipidomics research, enabling researchers to gain deeper insights into the complex lipidome of the brain.

CONCLUSIONS

A comprehensive understanding of the broad spectrum of lipidomics alterations in HD is vital for precise diagnostic evaluation and effective disease management. The integration of lipidomics with artificial intelligence and interdisciplinary collaboration holds promise for addressing the clinical variability of HD.

Evaluation of Salivary Diagnostics: Applications, Benefits, Challenges, and Future Prospects in Dental and Systemic Disease Detection

Saliva is a multifaceted biological fluid that plays a pivotal role in oral health and overall well-being. It is primarily produced by major salivary glands, with additional contributions from minor glands. Saliva is essential for various physiological functions, including oral lubrication, digestion, and defense against pathogens. Its intricate composition comprises proteins, electrolytes, enzymes, hormones, and microbial DNA, enabling it to act as a dynamic indicator of both local and systemic health. A literature search was conducted using PubMed, Web of Science, and Google Scholar to identify relevant studies published up to June 2024. The included studies involved human participants and provided original data or comprehensive reviews on salivary biomarkers. The findings indicate that salivary diagnostics show promise in diagnosing and monitoring systemic conditions such as diabetes and cardiovascular diseases, with salivary glucose levels correlating well with blood glucose levels. Biomarkers such as C-reactive protein (CRP) have been linked to cardiovascular risk, while saliva has been explored for cancer detection, including pancreatic and prostate cancers. Advances in techniques such as enzyme-linked immunosorbent assay (ELISA), saliva omics, and single-cell sequencing have furthered salivary diagnostics, providing insights into disease mechanisms. Additionally, quantitative mass spectrometry (qMS) and Raman spectroscopy (RS) contribute to non-invasive diagnostics for various conditions, including cancer. Collecting saliva samples from healthy individuals is crucial for early disease detection and evaluating treatment efficacy. This review underscores the growing importance of salivary tests in dental practice and their potential for diagnosing various health conditions. Further research is essential to address challenges related to variability and standardization. Dentists and healthcare professionals should consider incorporating salivary tests into clinical decision-making to enhance patient outcomes.

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.

Age-related features of the pattern of oral fluid patients with non-alcoholic fatty liver disease

INTRODUCTION

In recent years, non-invasive screening methods for diagnosing various human conditions, including those corresponding to biological age, have attracted great interest, one of the sources for non-invasive research of which is oral fluid.

Technical considerations regarding saliva sample collection to achieve comparable protein identification and detection via one- and two-dimensional gel electrophoresis among humans

Background and aims

Recently, demands towards identifying various molecules in support of stress detection and potential clinical utilization are dramatically increasing. Moreover, the accuracy with which researchers quantify these informative molecules is now far more improved when compared to the past. As RNA or protein markers are conventionally detected via repeated invasive procedures from blood, it is critical to develop secure technologies to obtain the desired information via less stressful methodologies, such as saliva collection. Moreover, for superb interpretation, it became equally significant to obtain the information from the same exact specimen. RNA is easily degradable, thus it is paramount to supplement the samples with protective agents, such as RNAlater, to achieve accurate quantitative results.

Methods

In our research we investigated whether and how this commonly applied RNA protection procedure influences protein and peptide separation of the human saliva via quantitative two-dimensional protein electrophoresis.

Results

Our results revealed, in contrary to previously published data regarding plasma, the addition of RNAlater to saliva samples negatively influences isoelectric focusing and protein detection. We equally found the application oftentimes employed referred to as selective precipitation and reduction-alkylation, partially rescued separation, however, with a significant loss in protein yield and quality when compared to untreated samples.

Conclusion

Our results suggest collection of human saliva for biomarker identification must be performed with extreme diligence. We propose application of RNAlater should be avoided and snap freezing of the collected saliva is recommended when joint protein and RNA quantification is the ultimate goal.

Understanding the Interaction of Röntgen Radiation Employed in Computed Tomography/Cone Beam Computed Tomography Investigations of the Oral Cavity by Means of Surface-Enhanced Raman Spectroscopy Analysis of Saliva

The use of Raman spectroscopy, particularly surface-enhanced Raman spectroscopy (SERS), offers a powerful tool for analyzing biochemical changes in biofluids. This study aims to assess the modifications occurring in saliva collected from patients before and after exposure to cone beam computed tomography (CBCT) and computed tomography (CT) imaging. SERS analysis revealed significantly amplified spectra in post-imaging samples compared to pre-imaging samples, with pronounced intensification of thiocyanate and opiorphin bands, which, together with proteins, dominated the spectra. The changes were more pronounced in the case of CT as compared to CBCT, probably due to the use of a high radiation dose in the case of the first-mentioned technique. These findings underscore the impact of CBCT and CT on salivary composition, highlighting the relevance of SERS as a sensitive method for detecting subtle molecular changes in biofluids post-radiation exposure. This study's results emphasize the importance of monitoring biochemical markers in patients undergoing diagnostic imaging to better understand the systemic effects of ionizing radiation.

Salivary biomarkers for early detection of oral squamous cell carcinoma (OSCC) and head/neck squamous cell carcinoma (HNSCC): A systematic review and network meta-analysis

Oral cancer became a very common condition. WHO estimates that there are 4 cases of lip and oral cavity cancer for every 100,000 people worldwide. The early diagnosis of cancers is currently a top focus in the health sector. Recent systematic reviews and meta-analyses have identified promising biomarkers for early detection in several original research investigations. However, it is still unclear the quality of these evidence and which biomarker performs the best in terms of early detection. Therefore, the objective was, to map the methodological and reporting quality of available oral squamous cell carcinoma (OSCC) or head/neck squamous cell carcinoma (HNSCC) systematic reviews and meta-analysis. Secondly, to evaluate diagnostic accuracy of salivary biomarkers for common craniofacial cancers and to compare the diagnostic value of different salivary biomarkers. PubMed, Scopus, Web of Science, Embase and Cochrane Library electronic databases were used to map the methodological and reporting quality of the systematic reviews and meta-analysis conducted on the HNSCC, OSCC using the AMSTAR-2 checklist. The inclusion criteria were systematic reviews and meta-analysis published in the topic of HNSCC and OSCC biomarkers. Exclusion criteria were no animal studies; original primary studies, due to limitation of competency in other languages articles with language other than English were excluded. The sensitivity and specificity were calculated for salivary biomarkers and ranked according to network meta-analysis principles. A total of N = 5893 patients were included from four meta-analysis studies. All together, these included n = 37 primary studies. n = 94 biomarkers were pooled from these four meta-analyses and categorised into the stages at which they were detected (I-IV). In OSCC, Chemerin and MMP-9 displayed the highest sensitivity, registering 0.94 (95% CI 0.78, 1.00) and a balanced accuracy of 0.93. Phytosphingosine closely followed, with a sensitivity of 0.91 (95% CI 0.68, 0.99) and a balanced accuracy of 0.87. For HNSCC, the top three biomarkers are Actin, IL-1β Singleplex, and IL-8 ELISA. Actin leads with a sensitivity of 0.91 (95% CI 0.68-0.99), a specificity of 0.67, and an overall accuracy of 0.79. Subsequently, IL-1β Singleplex exhibits a sensitivity of 0.62 (95% CI 0.30-0.88), a specificity of 0.89, and an accuracy of 0.75, followed by IL-8 ELISA with a sensitivity of 0.81 (95% CI 0.54-0.97), a specificity of 0.59, and an accuracy of 0.70. In conclusion, there was highest sensitivity for MMP-9 and chemerin salivary biomarkers. There is need of further more studies to identify biomarkers for HNSCC and OSCC.

Salivary Metabolomics in Patients with Long COVID-19 Infection

Background: Long COVID-19 has been characterized by the presence of symptoms lasting longer than 4 weeks after the acute infection. The pathophysiology of clinical manifestations still lacks knowledge. Objective: The objective of this paper was to evaluate metabolite abundance in the saliva of long COVID patients 60 days after hospital discharge. Methods: A convenience sample was composed of 30 post-discharge patients with long COVID and seven non-COVID-19 controls. All COVID-19 patients were evaluated by demographic characteristics, spirometry, 6 min walk test (6mWT), Saint George Respiratory Questionnaire (SGRQ), and body composition. Metabolomics was performed on saliva. Results: The long COVID-19 patients were 60.4 ± 14.3 years-old, and 66% male. Their lean body mass was 30.7 ± 7.3 kg and fat mass, 34.4 ± 13.7 kg. Spirometry evaluation showed forced vital capacity (FVC) of 3.84 ± 0.97 L with 96.0 ± 14.0% of the predicted value, and forced expiratory volume in the first second (FEV1) of 3.11 ± 0.83 L with 98.0 ± 16.0 of the predicted value. The long COVID-19 patients had reduced maximal inspiratory (90.1 ± 31.6 cmH2O) and maximal expiratory (97.3 ± 31.0 cmH2O) pressures. SGRQ showed domain symptoms of 32.3 ± 15.2, domain activities of 41.9 ± 25.6, and domain impact 13.7 ± 11.4, with a mean of 24.3 ± 14.9%. Physical capacity measured by distance covered in the 6mWT was 418.2 ± 130 m with a 73.3% (22.3-98.1) predictive value. The control group consisted of 44.1 ± 10.7-year-old men with a body mass index of 26.5 ± 1.66 Kg/m2. Metabolomics revealed 19 differentially expressed metabolites; expression was lower in 16 metabolites, and 2 metabolites were absent in the COVID-19 patients compared to controls. Calenduloside G methyl ester (p = 0.03), Gly Pro Lys (p = 0.0001), and creatine (p = 0.0001) expressions were lower in patients than controls. Conclusions: Long COVID-19 patients present less abundance of calenduloside G methyl ester, Gly Pro Lys, and creatine in saliva than healthy controls. Lower creatine abundance may be related to reduced physical capacity and fatigue.

The Variability of the Salivary Antimicrobial Peptide Profile: Impact of Lifestyle

Saliva is crucial in maintaining oral health; its composition reflects the body's physiological and diseased state. Among salivary components, antimicrobial peptides (AMPs) stand out for their broad antimicrobial activities and role in modulating the oral microbiota and innate immune response. Local and systemic diseases can affect the levels of AMPs in saliva, making them attractive biomarkers. However, the large variability in their concentrations hampers their use in diagnostics. Knowledge of the various factors influencing the profile of salivary AMPs is essential for their use as biomarkers. Here, we examine how lifestyle factors such as physical activity, dietary supplementation, tobacco smoking, and psychological stress impact salivary AMP levels. By understanding these sources of variability, we can take a step forward in using AMPs for diagnostics and prognostics and develop new tailored and preventative approaches.

Salivary diagnostics: opportunities and challenges

Saliva contains a diverse array of biomarkers indicative of various diseases. Saliva testing has been a major advancement towards non-invasive point-of-care diagnosis with clinical significance. However, there are challenges associated with salivary diagnosis from sample treatment and standardization. This review highlights the biomarkers in saliva and their role in identifying relevant diseases. It provides an overview and discussion about the current practice of saliva collection and processing, and advancements in saliva detection systems from in vitro methods to wearable oral devices. The review also addresses challenges in saliva diagnostics and proposes solutions, aiming to offer a comprehensive understanding and practical guidance for improving saliva-based detection in clinical diagnosis. Saliva diagnosis provides a rapid, effective, and safe alternative to traditional blood and urine tests for screening large populations and enhancing infectious disease diagnosis and surveillance. It meets the needs of various fields such as disease management, drug screening, and personalized healthcare with advances in saliva detection systems offering high sensitivity, fast response times, portability, and automation. Standardization of saliva collection, treatment, biomarker discovery, and detection between different laboratories needs to be implemented to obtain reliable salivary diagnosis in clinical practice.

Saliva metabolomics: concepts and applications in oral disorders

OBJECTIVES

The purpose of this review was to present the basic concepts of metabolomics methodology and the use of saliva for diagnostic, prognostic, and predictive strategies.

MATERIAL AND METHODS

This review followed the focus in: "saliva metabolomics" and "oral diseases". The authors searched studies on PubMed database. The inclusion criteria were original studies and reviews that assessed metabolomics techniques. A descriptive analysis was performed considering the study design, approach system, clinical steps, and tools for the determination of profile or biomarkers metabolites, and the advantages and disadvantages.

RESULTS

Metabolomic analyses use a combination of analytical instrumentation and informatic tools to provide information on metabolite characteristics. In this review we described different technologies applied and the advantages and limitations of each technique. Furthermore, in the literature search, we retrieved 25 studies that investigated saliva metabolites in oral diseases: 8 studies used targeted analysis and 17 untargeted metabolomics approaches. Most studies included patients with periodontal diseases, oral squamous cell carcinoma, and Sjögren Syndrome. The most frequently reported metabolites were glycine, leucine, phenylalanine, dipeptides, linoleic acid, arachidonic acid, tyrosine, choline, taurine, lactate, valine, and proline.

CONCLUSIONS

Metabolomics analysis has emerged as a powerful tool for tumor diagnosis and to enhance tumor classification, including salivary gland tumors (SGTs). It also holds promise for developing personalized treatment plans and defining more precise prognostic categories.

CLINICAL RELEVANCE

Metabolomics is the most functional and comprehensive technique for monitoring and understanding gene functions and identifying the biochemical state of an organism in response to genetic and environmental changes.

Toward Digital Periodontal Health: Recent Advances and Future Perspectives

Periodontal diseases, ranging from gingivitis to periodontitis, are prevalent oral diseases affecting over 50% of the global population. These diseases arise from infections and inflammation of the gums and supporting bones, significantly impacting oral health. The established link between periodontal diseases and systemic diseases, such as cardiovascular diseases, underscores their importance as a public health concern. Consequently, the early detection and prevention of periodontal diseases have become critical objectives in healthcare, particularly through the integration of advanced artificial intelligence (AI) technologies. This paper aims to bridge the gap between clinical practices and cutting-edge technologies by providing a comprehensive review of current research. We examine the identification of causative factors, disease progression, and the role of AI in enhancing early detection and treatment. Our goal is to underscore the importance of early intervention in improving patient outcomes and to stimulate further interest among researchers, bioengineers, and AI specialists in the ongoing exploration of AI applications in periodontal disease diagnosis.

Oral microbiome in human health and diseases

The oral cavity contains the second-largest microbiota in the human body. The cavity's anatomically and physiologically diverse niches facilitate a wide range of symbiotic bacteria living at distinct oral sites. Consequently, the oral microbiota exhibits site specificity, with diverse species, compositions, and structures influenced by specific aspects of their placement. Variations in oral microbiota structure caused by changes in these influencing factors can impact overall health and lead to the development of diseases-not only in the oral cavity but also in organs distal to the mouth-such as cancer, cardiovascular disease, and respiratory disease. Conversely, diseases can exacerbate the imbalance of the oral microbiota, creating a vicious cycle. Understanding the heterogeneity of both the oral microbiome and individual humans is important for investigating the causal links between the oral microbiome and diseases. Additionally, understanding the intricacies of the oral microbiome's composition and regulatory factors will help identify the potential causes of related diseases and develop interventions to prevent and treat illnesses in this domain. Therefore, turning to the extant research in this field, we systematically review the relationship between oral microbiome dynamics and human diseases.

Comprehensive insights into oral squamous cell carcinoma: Diagnosis, pathogenesis, and therapeutic advances

Oral squamous cell carcinoma (OSCC) is considered the most common type of head and neck squamous cell carcinoma (HNSCC) as it holds 90 % of HNSCC cases that arise from multiple locations in the oral cavity. The last three decades witnessed little progress in the diagnosis and treatment of OSCC the aggressive tumor. However, in-depth knowledge about OSCC's pathogenesis, staging & grading, hallmarks, and causative factors is a prime requirement in advanced diagnosis and treatment for OSCC patients. Therefore present review was intended to comprehend the OSCCs' prevalence, staging & grading, molecular pathogenesis including premalignant stages, various hallmarks, etiology, diagnostic methods, treatment (including FDA-approved drugs with the mechanism of action and side effects), and theranostic agents. The current review updates that for a better understanding of OSCC progress tumor-promoting inflammation, sustained proliferative signaling, and growth-suppressive signals/apoptosis capacity evasion are the three most important hallmarks to be considered. This review suggests that among all the etiology factors the consumption of tobacco is the major contributor to the high incidence rate of OSCC. In OSCC diagnosis biopsy is considered the gold standard, however, toluidine blue staining is the easiest and non-invasive method with high accuracy. Although there are various therapeutic agents available for cancer treatment, however, a few only are approved by the FDA specifically for OSCC treatment. The present review recommends that among all available OSCC treatments, the antibody-based CAR-NK is a promising therapeutic approach for future cancer treatment. Presently review also suggests that theranostics have boosted the advancement of cancer diagnosis and treatment, however, additional work is required to refine the role of theranostics in combination with different modalities in cancer treatment.

Comparison of the effects of submucosal hyaluronidase and dexamethasone on postoperative edema, pain, trismus, and infection following impacted third molar surgery

BACKGROUND

Limiting postoperative edema, pain, trismus, and infection is crucial for smooth healing. This prospective, controlled clinical trial investigated and compared the effectiveness of dexamethasone and hyaluronidase in relieving these complications.

METHODS

In groups Ia and IIa, 8 mg of dexamethasone and 150 IU of hyaluronidase were administered following the removal of impacted teeth, respectively. The contralateral sides (groups Ib and IIb) were determined as control groups. Edema, pain, trismus, and infection were clinically evaluated on the 1st, 2nd, 3rd, and 7th postoperative days.

RESULTS

60 patients were enrolled in the study. Hyaluronidase provided significantly more edema relief than dexamethasone on the 1st, 2nd, 3rd, and 7th postoperative days (P = 0.031, 0.002, 0.000, and 0.009, respectively). No statistical difference was found between dexamethasone and hyaluronidase in VAS and rescue analgesic intake amount values for all time points. Hyaluronidase was more effective in reducing trismus than dexamethasone on the 2nd and 3rd postoperative days (P = 0.029, 0.024, respectively). Neither of the agents significantly increased the postoperative infection rate.

CONCLUSIONS

Hyaluronidase can be selected when postoperative excessive edema and trismus are anticipated. Dexamethasone may be a cost-effective option if postoperative pain control is merely targeted.

TRIAL REGISTRATION

This trial was registered in the Clinical Trials Protocol Registration and Results System (ClinicalTrials.gov identifier number: NCT05466604) on 20/07/2022.

Integration of precision medicine into the dental care setting

This narrative review aims to discuss the incorporation of novel medical concepts and tools into dental practice, with the goal of improving early diagnosis and exploring new personalized treatment options for oral pathologies, such as caries and periodontitis. Preventative dental approaches concentrate on the timely detection of oral infections and the integration of biomarker analysis to recognize pathogenic changes at early stage of disease. Likewise, periodic monitoring after the treatment is relevant to ensure the balance in the oral biofilms and prevent relapse. Additionally, more attention has shifted towards the contributing factors to disease development, such as essential nutrients. Sufficient levels of vitamin C, vitamin D and zinc pre- and post-operatively are employed to boost immune function and reduce the risk of postoperative infections. Omega-3 fatty acids, melatonin, and antioxidants like vitamin E, which have anti-inflammatory properties, are utilized to help minimize excessive inflammation and promote faster recovery. The data presented in this manuscript emphasize the crucial integration of innovative healthcare concepts and tools into dental practices. By adopting a more holistic view of the patient, clinicians can tailor treatments to each individual's predispositions, lifestyle, and oral health conditions. This review also highlights the potential of salivary biomarkers and point-of-care technologies in enhancing early diagnostic accuracy and personalizing treatment. Bridging the gap between oral and systemic health is the most effective approach to improving patient quality of life. These findings underscore the importance of continued interdisciplinary collaboration in dentistry.

The role of puff volume in vaping emissions, inhalation risks, and metabolic perturbations: a pilot study

Secondhand vaping exposure is an emerging public health concern that remains understudied. In this study, saliva and exhaled emissions from ENDS users (secondhand) and non-ENDS users (baseline) were collected, firsthand emissions were generated using an automated ENDS aerosol generation system programmed to simulate puffing topography profiles collected from ENDS users. Particulate concentrations and sizes along with volatile organic compounds were characterized. We revealed puffing topography metrics as potential mediators of firsthand and secondhand particle and chemical exposures, as well as metabolic and respiratory health outcomes. Particle deposition modeling revealed that while secondhand emissions displayed smaller deposited mass, total and pulmonary particle deposition fractions were higher than firsthand deposition levels, possibly due to smaller secondhand emission particle diameters. Lastly, untargeted metabolomic profiling of salivary biomarkers of lung injury due to firsthand ENDS exposures revealed potential early indicators of respiratory distress that may also be relevant in bystanders exposed to secondhand vaping scenarios. By leveraging system toxicology, we identified 10 metabolites, including leukotriene D4, that could potentially serve as biomarkers for ENDS use, exposure estimation, and the prediction of vaping-related disease. This study highlights characterization of vaping behavior is an important exposure component in advancing our understanding of potential health effects in ENDS users and bystanders.

A highly sensitive 3base™ assay for detecting Streptococcus pyogenes in saliva during controlled human pharyngitis

Streptococcus pyogenes (Group A Streptococcus; GAS) is a Gram-positive bacterium responsible for substantial human mortality and morbidity. Conventional diagnosis of GAS pharyngitis relies on throat swab culture, a low-throughput, slow, and relatively invasive 'gold standard'. While molecular approaches are becoming increasingly utilized, the potential of saliva as a diagnostic fluid for GAS infection remains largely unexplored. Here, we present a novel, high-throughput, sensitive, and robust speB qPCR assay that reliably detects GAS in saliva using innovative 3base™ technology (Genetic Signatures Limited, Sydney, Australia). The assay has been validated on baseline, acute, and convalescent saliva samples generated from the Controlled Human Infection for Vaccination Against Streptococcus (CHIVAS-M75) trial, in which healthy adult participants were challenged with emm75 GAS. In these well-defined samples, our high-throughput assay outperforms throat culture and conventional qPCR in saliva respectively, affirming the utility of the 3base™ platform, demonstrating the feasibility of saliva as a diagnostic biofluid, and paving the way for the development of novel non-invasive approaches for the detection of GAS and other oropharyngeal pathogens.

Alterations in the Salivary Microbiome and Metabolism in Patients With Carotid Atherosclerosis from Rural Northeast China

BACKGROUND

Periodontitis and atherosclerosis are both chronic inflammatory diseases with a high prevalence. Increasing evidence supports the independent association between severe periodontitis and atherosclerotic cardiovascular disease, in which oral microorganisms may play an important role. We aimed to evaluate the characteristic changes of salivary microbiome and metabolome in patients with carotid atherosclerosis (CAS) and periodontitis.

METHODS AND RESULTS

The subjects were obtained from a cross-sectional study that included 1933 participants aged 40 years or older from rural northeast China. The study enrolled 48 subjects with CAS and 48 controls without CAS matched by sex, age, body mass index, and prevalence of hypertension, diabetes, and dyslipidemia. We performed full-length 16S rDNA gene sequencing and untargeted metabolomics of saliva samples from 96 subjects. We found that CAS was closely associated with an increased abundance of Streptococcus, Lactobacillus, and Cutibacterium. Furthermore, patients with CAS had higher prevalence of severe periodontitis than the control group. Notably, periodontal pathogens such as Tannerella and Anaeroglobus were not only associated with periodontitis but also enriched in patients with CAS, whereas periodontal health-associated Neisseria was more abundant in those without CAS. We also identified 2 lipid metabolism pathways, including glycerophospholipid and sphingolipid metabolism, as associated with CAS. The levels of trimethylamine N-oxide and inflammatory mediator leukotriene D4 were significantly higher in patients with CAS, whereas the levels of carnosine were significantly lower, than those in controls. Additionally, serum levels of inflammatory marker high-sensitivity C-reactive protein were significantly increased in CAS and positively correlated with the abundance of Anaeroglobus and leukotriene D4 in saliva.

CONCLUSIONS

Our study suggests that characteristic changes in salivary microbiota and metabolites are closely related to CAS, and periodontitis and associated microorganisms may be involved in the initiation and progression of CAS.

Non-invasive diagnostic test for lung cancer using biospectroscopy and variable selection techniques in saliva samples

Lung cancer is one of the most commonly occurring malignant tumours worldwide. Although some reference methods such as X-ray, computed tomography or bronchoscope are widely used for clinical diagnosis of lung cancer, there is still a need to develop new methods for early detection of lung cancer. Especially needed are approaches that might be non-invasive and fast with high analytical precision and statistically reliable. Herein, we developed a swab "dip" test in saliva whereby swabs were analysed using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy harnessed to principal component analysis-quadratic discriminant analysis (QDA) and variable selection techniques employing successive projections algorithm (SPA) and genetic algorithm (GA) for feature selection/extraction combined with QDA. A total of 1944 saliva samples (56 designated as lung-cancer positive and 1888 designed as controls) were obtained in a lung cancer-screening programme being undertaken in North-West England. GA-QDA models achieved, for the test set, sensitivity and specificity values of 100.0% and 99.1%, respectively. Three wavenumbers (1422 cm-1, 1546 cm-1 and 1578 cm-1) were identified using the GA-QDA model to distinguish between lung cancer and controls, including ring C-C stretching, CN adenine, Amide II [δ(NH), ν(CN)] and νs(COO-) (polysaccharides, pectin). These findings highlight the potential of using biospectroscopy associated with multivariate classification algorithms to discriminate between benign saliva samples and those with underlying lung cancer.

Role of Oral Veillonella Species in Predicting Surgical Site Infections After Maxillofacial Trauma: A Prospective Observational Study

INTRODUCTION

There are comparatively fewer surgical site infections after craniofacial trauma than after trauma to the extremities, and the etiology is complex. Gram-negative facultative anaerobic bacteria Veillonella is a common commensal in the oral cavity and has been linked to osteomyelitis and surgical site infections in prosthetic joint infections. They serve as early biological indicators.

AIMS/OBJECTIVES

This study aims to assess the presence of Veillonella in patients presenting with maxillofacial trauma, to document the difference in colony count in patients requiring surgical intervention at different time intervals as against patients with surgical site infections, and to provide better hospital care and management so as to improve the standard of care with an attempt to prevent the possibility of postoperative surgical site infections.

METHODOLOGY

In this study, individuals with trauma/fractures of the maxillofacial region requiring surgical intervention at varied time spans, early, intermediate, and late, were included. After obtaining informed consent, the examination was done; the fracture type and site were noted, and a swab was taken on the day of admission, on the day of surgery, and on the day of discharge and given for microbiological evaluation. Findings were recorded.

RESULTS

The primary and secondary objectives of the study were established. The mean colony count in colony-forming units/milliliter for patients undergoing early surgical intervention, on the day of admission, was 2.01E+0.6. On the day of discharge, the mean colony count was 1.51E+0.6. In contrast, for patients with surgical site infection, on the day of admission, the mean was 6.5E+0.7, and on the day of discharge, the mean colony count reduced to 4.01E+0.6. The time-colony-forming unit graph showed a difference in the colony count of Veillonella in patients operated at different time intervals as against patients with surgical site infection and modified relation with a number of other oral commensals. The colony count in patients with osteomyelitis was found and compared.

CONCLUSION

There is a change in the colony count of Veillonella species and its relation to their commensals when intervened at different time intervals. Our study indicates that the estimation of Veillonella species and the colony count could aid in determining the possibility of a surgical site infection. This study also stresses on the appropriate reporting of maxillofacial trauma in cases of a poly-trauma for appropriate management.

Colorimetric sensing for translational applications: from colorants to mechanisms

Colorimetric sensing offers instant reporting via visible signals. Versus labor-intensive and instrument-dependent detection methods, colorimetric sensors present advantages including short acquisition time, high throughput screening, low cost, portability, and a user-friendly approach. These advantages have driven substantial growth in colorimetric sensors, particularly in point-of-care (POC) diagnostics. Rapid progress in nanotechnology, materials science, microfluidics technology, biomarker discovery, digital technology, and signal pattern analysis has led to a variety of colorimetric reagents and detection mechanisms, which are fundamental to advance colorimetric sensing applications. This review first summarizes the basic components (e.g., color reagents, recognition interactions, and sampling procedures) in the design of a colorimetric sensing system. It then presents the rationale design and typical examples of POC devices, e.g., lateral flow devices, microfluidic paper-based analytical devices, and wearable sensing devices. Two highlighted colorimetric formats are discussed: combinational and activatable systems based on the sensor-array and lock-and-key mechanisms, respectively. Case discussions in colorimetric assays are organized by the analyte identities. Finally, the review presents challenges and perspectives for the design and development of colorimetric detection schemes as well as applications. The goal of this review is to provide a foundational resource for developing colorimetric systems and underscoring the colorants and mechanisms that facilitate the continuing evolution of POC sensors.

Core-shell niobium(v) oxide@molecularly imprinted polythiophene nanoreceptors for transformative, real-time creatinine analysis

Creatinine, a byproduct of muscle metabolism, is typically filtered by the kidneys. Deviations from normal concentrations of creatinine in human saliva serve as a crucial biomarker for renal diseases. Monitoring these levels becomes particularly essential for individuals undergoing dialysis and those with kidney conditions. This study introduces an innovative disposable point-of-care (PoC) sensor device designed for the prompt detection and continuous monitoring of trace amounts of creatinine. The sensor employs a unique design, featuring a creatinine-imprinted polythiophene matrix combined with niobium oxide nanoparticles. These components are coated onto a screen-printed working electrode. Thorough assessments of creatinine concentrations, spanning from 0 to 1000 nM in a redox solution at pH 7.4 and room temperature, are conducted using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The devised sensor exhibits a sensitivity of 4.614 μA cm-2 nM-1, an impressive trace level limit of detection at 34 pM, and remarkable selectivity for creatinine compared to other analytes found in human saliva, such as glucose, glutamine, urea, tyrosine, etc. Real saliva samples subjected to the sensor reveal a 100% recovery rate. This sensor, characterized by its high sensitivity, cost-effectiveness, selectivity, and reproducibility, holds significant promise for real-time applications in monitoring creatinine levels in individuals with kidney and muscle-related illnesses.

Relationship between oral hypofunction and salivary biomarkers in older adults: a cross-sectional study

BACKGROUND

Oral health problems have increased among older adults. Oral hypofunction is characterized by seven signs and symptoms: oral uncleanness, oral dryness, decline in occlusal force, decline in the movement function of the tongue and lips, decline in tongue pressure, decline in masticatory function, and decline in swallowing function, the latter being a significant risk factors for oral frailty. Recent research has suggested that salivary biomarkers can be used to assess not only oral diseases, including dental caries and periodontitis, but also systemic diseases, such as cancer and diabetes mellitus. This cross-sectional study investigated the relationship between oral hypofunction and the levels of salivary biomarkers.

METHODS

In total, 116 patients, aged 65 years or older, were included in this cross-sectional study. If three or more signs or symptoms in seven kinds of tests met the criteria of each test, oral hypofunction was diagnosed. The levels of biomarkers in the saliva collected from the patients were analyzed using an enzyme-linked immunosorbent assay.

RESULTS

In total, 63.8% of patients were diagnosed with oral hypofunction. Multivariable linear regression analysis showed that calprotectin levels in the saliva were significantly related to oral moisture and masticatory function. Furthermore, 8-OHdG levels in saliva were associated with the movement function of the tongue and lips and oral hygiene level, and salivary AGE correlated only with the movement function of the tongue and lips. Multiple logistic regression analysis revealed that calprotectin levels in the saliva were significantly correlated with the prevalence of oral hypofunction, even after adjusting for age, sex, and periodontal status. However, none of the biomarker levels in the saliva had a significant relationship with the number of examinations outside the reference range.

CONCLUSIONS

Calprotectin, 8-OHdG, and AGE levels are associated with oral hypofunction in older adults.

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.

Severe acute respiratory syndrome coronavirus 2 pathology and cell tropism in tongue tissues of COVID-19 autopsies

Since 2019, Coronavirus Disease 2019(COVID-19) has affected millions of people worldwide. Except for acute respiratory distress syndrome, dysgeusis is also a common symptom of COVID-19 that burdens patients for weeks or permanently. However, the mechanisms underlying taste dysfunctions remain unclear. Here, we performed complete autopsies of five patients who died of COVID-19. Integrated tongue samples, including numerous taste buds, salivary glands, vessels, and nerves were collected to map the pathology, distribution, cell tropism, and receptor distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the tongue. Our results revealed that all patients had moderate lymphocyte infiltration around the salivary glands and in the lamina propria adjacent to the mucosa, and pyknosis in the epithelia of taste buds and salivary glands. This may be because the serous acini, salivary gland ducts, and taste buds are the primary sites of SARS-CoV-2 infection. Multicolor immunofluorescence showed that SARS-CoV-2 readily infects Keratin (KRT)7+ taste receptor cells in taste buds, secretory cells in serous acini, and inner epithelial cells in the ducts. The major receptors, angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), were both abundantly expressed in these cells. Viral antigens and receptor were both rarely detected in vessels and nerves. This indicates that SARS-CoV-2 infection triggers pathological injury in the tongue, and that dysgeusis may be directly related to viral infection and cellular damage.

The oral microbiome and oral and upper gastrointestinal diseases

Background

Microbiomes are essential components of the human body, and their populations are substantial. Under normal circumstances, microbiomes coexist harmoniously with the human body, but disturbances in this equilibrium can lead to various diseases. The oral microbiome is involved in the occurrence and development of many oral and gastrointestinal diseases. This review focuses on the relationship between oral microbiomes and oral and upper gastrointestinal diseases, and therapeutic strategies aiming to provide valuable insights for clinical prevention and treatment.

Methods

To identify relevant studies, we conducted searches in PubMed, Google Scholar, and Web of Science using keywords such as "oral microbiome," "oral flora, " "gastrointestinal disease, " without any date restrictions. Subsequently, the retrieved publications were subject to a narrative review.

Results

In this review, we found that oral microbiomes are closely related to oral and gastrointestinal diseases such as periodontitis, dental caries, reflux esophagitis, gastritis, and upper gastrointestinal tumors (mainly the malignant ones). Oral samples like saliva and buccal mucosa are not only easy to collect, but also display superior sample stability compared to gastrointestinal tissues. Consequently, analysis of the oral microbiome could potentially serve as an efficient preliminary screening method for high-risk groups before undergoing endoscopic examination. Besides, treatments based on the oral microbiomes could aid early diagnosis and treatment of these diseases.

Conclusions

Oral microbiomes are essential to oral and gastrointestinal diseases. Therapies centered on the oral microbiomes could facilitate the early detection and management of these conditions.

Evaluation of Salivary Biomarkers and Spirometry for Diagnosing COPD in Non-Smokers and Smokers of Polish Origin

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition with global implications. Accurate and timely diagnosis is critical; however, traditional diagnostic methods (based on spirometry) show limitations, prompting the search for predictive biomarkers and modern diagnostic techniques. This study explored the validation of COPD-related biomarkers (C-reactive protein, procalcitonin, neutrophil elastase, and alpha-1 antitrypsin) in saliva. A diverse cohort, including healthy non-smokers, healthy smokers, and COPD patients of Polish origin, underwent spirometry and marker analysis. The data correlated with clinical factors, revealing noteworthy relations. Firstly, salivary biomarker levels were compared with serum concentrations, demonstrating notable positive or negative correlations, depending on the factor. Further analysis within healthy individuals revealed associations between biomarker levels, spirometry, and clinical characteristics such as age, sex, and BMI. Next, COPD patients exhibited an enhanced concentration of biomarkers compared to healthy groups. Finally, the study introduced a breathing assessment survey, unveiling significant associations between self-perceived breathing and spirometric and tested parameters. Outcomes emphasized the relevance of subjective experiences in COPD research. In conclusion, this research underscored the potential of salivary biomarkers as diagnostic tools for COPD, offering a non-invasive and accessible alternative to traditional methods. The findings paved the way for improved modern diagnostic approaches.

Raman hyperspectroscopy of saliva and machine learning for Sjögren's disease diagnostics

Sjögren's disease is an autoimmune disorder affecting exocrine glands, causing dry eyes and mouth and other morbidities. Polypharmacy or a history of radiation to the head and neck can also lead to dry mouth. Sjogren's disease is often underdiagnosed due to its non-specific symptoms, limited awareness among healthcare professionals, and the complexity of diagnostic criteria, limiting the ability to provide therapy early. Current diagnostic methods suffer from limitations including the variation in individuals, the absence of a single diagnostic marker, and the low sensitivity and specificity, high cost, complexity, and invasiveness of current procedures. Here we utilized Raman hyperspectroscopy combined with machine learning to develop a novel screening test for Sjögren's disease. The method effectively distinguished Sjögren's disease patients from healthy controls and radiation patients. This technique shows potential for development of a single non-invasive, efficient, rapid, and inexpensive medical screening test for Sjögren's disease using a Raman hyper-spectral signature.