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Oral cancer, representing 2-4% of all cancer cases, predominantly consists of Oral Squamous Cell Carcinoma (OSCC), which makes up 90% of oral malignancies. Early detection of OSCC is crucial, and identifying specific proteins in saliva as biomarkers could greatly improve early diagnosis. Here, we proposed a strategy to pinpoint candidate biomarkers. Starting from a list of salivary proteins detected in 10 OSCC patients and 20 healthy controls, we combined a univariate approach and a multivariate approach to select candidates. To reduce the number of proteins selected, a Protein-Protein Interaction network was built to consider only connected proteins. Then, an over-representation analysis (ORA) determined the enriched pathways. The network from 172 differentially abundant proteins highlighted 50 physically connected proteins, selecting relevant candidates for targeted experimental validations. Notably, proteins like Heat shock 70 kDa protein 1A/1B, Pyruvate kinase PKM, and Phosphoglycerate kinase 1 were suggested to be differentially regulated in OSCC patients, with implications for oral carcinogenesis and tumor growth. Additionally, the ORA revealed enrichment in immune system, complement, and coagulation pathways, all known to play roles in tumorigenesis and cancer progression. The employed method has successfully identified potential biomarkers for early diagnosis of OSCC using an accessible body fluid.

Objective: The aim of this study was to compare the salivary proteomic profile of smokeless tobacco users with that of non-users and oral cancer patients using Liquid Chromatography-Mass Spectrometry/ Mass Spectrometry (LC-MS/MS)., Methods: Saliva samples from 65 participants were collected in three groups: control (25 participants), smokeless tobacco users (25 participants), and oral cancer (15 participants)., Results: The analysis revealed 343 protein groups with significantly altered abundance in the saliva samples (P < 0.05). Among these, 43 out of 51 dysregulated proteins in the smokeless tobacco group were also dysregulated in the oral cancer group. Notably, Apolipoprotein A1 (ApoA1) and Pon1 were found to be significantly increased in both smokeless tobacco users and oral cancer patients (p < 0.05). Furthermore, six out of the 20 most significantly altered proteins were mitochondrial proteins, and all of these were decreased relative to controls in both smokeless tobacco users and cancer samples., Conclusion: The proteomic profile of users of chewing (smokeless) tobacco (SLT) shows substantial overlap in the altered pathways and dysregulated proteins with those altered in oral cancer samples, suggesting that SLT use induces a shift toward an oncogenic state. Specifically indicated pathways included blood microparticles, platelet α-granules and protease inhibitors as well as indicators of oxidative stress and exogenous compound processing. What differentiates oral cancer samples from SLT users is enrichment of alterations related to cytoskeletal organisation and tissue remodelling., Clinical Significance: The findings emphasize the importance of salivary proteomic profiles because changes in certain proteins may be indicators for early oral cancer identification and risk assessment in smokeless tobacco users., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ticks, as hematophagous ectoparasites, can manipulate host immune and metabolic processes, causing tick-borne allergies such as α-Gal syndrome (AGS). Glycolipids with bound galactose-alpha-1-3-galactose (α-Gal) are potential allergenic molecules associated with AGS. Nevertheless, proteins and lipids lacking α-Gal modifications may contribute to tick salivary allergies and be linked to AGS. In this study, we characterized the effect of deglycosylated tick salivary proteins without lipids on treated zebrafish fed with dog food formulated with mammalian (beef, lamb, pork) meat by quantitative proteomics analysis of intestinal samples. The characterization and functional annotations of tick salivary lipids with low representation of glycolipids was conducted using a lipidomics approach. Results showed a significant effect of treatment with saliva and saliva deglycosylated protein fraction on zebrafish abnormal or no feeding (p < 0.005). Treatment with this fraction affected multiple metabolic pathways, defense responses to pathogens and protein metabolism, which correlated with abnormal or no feeding. Lipidomics analysis identified 23 lipid classes with low representation of glycolipids (0.70% of identified lipids). The lipid class with highest representation was phosphatidylcholine (PC; 26.66%) and for glycolipids it corresponded to diacylglycerol (DG; 0.48%). Qualitative analysis of PC antibodies revealed that individuals bitten by ticks were more likely to produce PC-IgG antibodies (p < 0.001). DG levels were significantly higher in tick salivary glands (p < 0.05) compared with tick saliva and salivary fractions. The α-Gal content was higher in tick saliva than in deglycosylated saliva and lipid fractions. These results support a possible role for tick salivary proteins and lipids without α-Gal modifications in AGS., (Copyright © 2024 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.)

In the present study, a comparative global high-throughput proteomic analysis strategy was used to identify proteomic differences between estrus and diestrus stage of estrous cycle in dairy cows. Saliva was collected from cows during estrus and diestrus, and subjected to LC-MS/MS-based proteomic analysis. A total of 2842 proteins were detected in the saliva of cows, out of which, 2437 and 1428 non-redundant proteins were identified in estrous and diestrous saliva, respectively. Further, it was found that 1414 and 405 salivary proteins were specific to estrus and diestrus, respectively while 1023 proteins were common to both groups. Among the significantly dysregulated proteins, the expression of 56 proteins was down-regulated (abundance ratio <0.5) while 40 proteins were up-regulated (abundance ratio > 2) in estrous compared to diestrous saliva. The proteins, such as HSD17B12, INHBA, HSP70, ENO1, SRD5A1, MOS, AMH, ECE2, PDGFA, OPRK1, SYN1, CCNC, PLIN5, CETN1, AKR1C4, NMNAT1, CYP2E1, and CYP19A1 were detected only in the saliva samples derived from estrous cows. Considerable number of proteins detected in the saliva of estrous cows were found to be involved in metabolic pathway, PI3K-Akt signaling pathway, toll-like receptor signaling pathway, steroid biosynthesis pathway, insulin signaling pathway, calcium signaling pathway, estrogen signaling pathway, oxytocin signaling pathway, TGF-β signaling pathway and oocyte meiosis. On the other hand, proteins detected in saliva of diestrous cows were involved mainly in metabolic pathway. Collectively, these data provide preliminary evidence of a potential difference in salivary proteins at different stages of estrous cycle in dairy cows.

The relationship between dental fluorosis and alterations in the salivary proteome remains inadequately elucidated. This study aimed to investigate the salivary proteome and fluoride concentrations in urine and drinking water among Thai individuals afflicted with severe dental fluorosis. Thirty-seven Thai schoolchildren, aged 6-16, were stratified based on Thylstrup and Fejerskov fluorosis index scores: 10 with scores ranging from 5 to 9 (SF) and 27 with a score of 0 (NF). Urinary and water fluoride levels were determined using an ion-selective fluoride electrode. Salivary proteomic profiling was conducted via LC-MS/MS, followed by comprehensive bioinformatic analysis. Results revealed significantly elevated urinary fluoride levels in the SF group (p = 0.007), whereas water fluoride levels did not significantly differ between the two cohorts. Both groups exhibited 104 detectable salivary proteins. The NF group demonstrated notable upregulation of LENG9, whereas the SF group displayed upregulation of LDHA, UBA1, S100A9, H4C3, and LCP1, all associated with the CFTR ion channel. Moreover, the NF group uniquely expressed 36 proteins, and Gene Ontology and pathway analyses suggested a link with various aspects of immune defense. In summary, the study hypothesized that the CFTR ion channel might play a predominant role in severe fluorosis and highlighted the depletion of immune-related salivary proteins, suggesting compromised immune defense in severe fluorosis. The utility of urinary fluoride might be a reliable indicator for assessing excessive fluoride exposure., (© 2024. The Author(s).)

Dental caries is a multifactorial chronic disease resulting from the intricate interplay among acid-generating bacteria, fermentable carbohydrates, and several host factors such as saliva. Saliva comprises several proteins which could be utilized as biomarkers for caries prevention, diagnosis, and prognosis. Mass spectrometry-based salivary proteomics approaches, owing to their sensitivity, provide the opportunity to investigate and unveil crucial cariogenic pathogen activity and host indicators and may demonstrate clinically relevant biomarkers to improve caries diagnosis and management. The present review outlines the published literature of human clinical proteomics investigations on caries and extensively elucidates frequently reported salivary proteins as biomarkers. This review also discusses important aspects while designing an experimental proteomics workflow. The protein-protein interactions and the clinical relevance of salivary proteins as biomarkers for caries, together with uninvestigated domains of the discipline are also discussed critically., (© 2022 John Wiley & Sons Ltd.)

Objective: Opiorphin is a pentapeptide secreted in saliva and has a strong analgesic effect. Salivary opiorphin has been shown to increase in orofacial pain and may act as a pain reliever in pain caused by denture-related ulcers. The current study aimed to evaluate the salivary opiorphin levels in traumatic ulcers caused by ill-fitting dentures and demonstrate whether there is any correlation between trauma-related pain levels and salivary opiorphin levels., Materials and Methods: Twenty-two individuals with new full dentures and a complaint of pain due to ill-fitting were included in this study. Patients were asked to rate their level of pain on a visual analog scale (VAS). Then, saliva specimens were collected at the first visit with the complaint of pain and 7 days following the denture adjustment., Results: The average saliva opiorphin level before and after denture adjustment were 19.29 ± 5.44 and 15.78 ± 3.95 ng/mL, respectively. A dependent (paired) t-test determined that the mean salivary opiorphin level differed statistically significantly before and after the adjustment of the dentures., Conclusions: The findings show that salivary opiorphin levels increase in pain associated with denture-related traumatic ulcers. Adjusting the dentures resulted in pain relief and a statistically significant reduction in opiorphin levels., (© 2023 Wiley Periodicals LLC.)

Diverse proteomics-based strategies have been applied to saliva to quantitatively identify diagnostic and prognostic targets for oral cancer. Considering that these targets may be regulated by events that do not imply variation in protein abundance levels, we hypothesized that changes in protein conformation can be associated with diagnosis and prognosis, revealing biological processes and novel targets of clinical relevance. For this, we employed limited proteolysis-mass spectrometry in saliva samples to explore structural alterations, comparing the proteome of healthy control and oral squamous cell carcinoma (OSCC) patients with and without lymph node metastasis. Thirty-six proteins with potential structural rearrangements were associated with clinical patient features including transketolase and its interacting partners. Moreover, N -glycosylated peptides contribute to structural rearrangements of potential diagnostic and prognostic markers. Altogether, this approach utilizes saliva proteins to search for targets for diagnosing and prognosing oral cancer and can guide the discovery of potential regulated sites beyond protein-level abundance.

Salivary stones are hardened, stony calcifications that primarily develop in the drainage duct of a salivary gland. They can lead to obstruction of the saliva flow, resulting in swelling and pain. Since the aetiology of salivary stones remains largely unclear, this was further investigated in this PhD study. A case-control review of patient records showed that systemic diseases and lifestyle factors most likely do not play a role in their occurrence. The biochemical composition of salivary stones removed by oral-maxillofacial surgeons was examined, revealing that large salivary stones have a different inorganic composition than small salivary stones. Several salivary proteins were detected in submandibular salivary stones, including lysozyme, s-IgA, and -amylase. Clumping together of these proteins may play a role in the initial formation of salivary stones.

Introduction: This longitudinal study assessed the association between salivary protein composition and the clinical onset/severity of oral mucositis (OM) in patients with head and neck tumours treated with intensity-modulated-radiotherapy (IMRT)., Methods: Saliva samples/clinical data were obtained from 40 head and neck cancer patients treated at Guy's Hospital before -IMRT(T0) and after-IMRT (T1 = 6 m, T2 = 12 m) (ethics approval/consent). Salivary flow rate, total protein concentration, and secretion rate were determined from saliva samples and compared with pre-treatment values. OM was assessed, total/specific salivary proteins, including mucin 5B and 7, IgA, cystatin-S, albumin, and α-amylase, were quantified., Results: 95% patients experienced OM during IMRT, with 33 subjects reaching grade 2&3. At T1, there was a significant reduction in salivary flow rate, total protein secretion rate, α-amylase and cystatin-S compared to baseline. Remarkably IMRT did not significantly alter mucin 5B and 7, or the IgA secretion rate at any time point. At T1, all the analyzed proteins were associated with the OM outcomes. In addition, there was a significant inverse correlation between IgA concentration at T0 and the severity of OM during IMRT., Conclusion: This study revealed significant associations between several salivary proteins and OM in patients with head and neck cancer undergoing IMRT. Further longitudinal studies are needed to confirm these results., Clinical Significance: The study contributes to the understanding of certain salivary proteins association with OM. This could be the first step towards identifying potential salivary markers that could offer perspectives for personalized medicine approaches to improve their quality of life (QoL)., Research Question: What is the association between salivary proteins and the occurrence and severity of OM in head and neck cancer patients?, Aim: To assess the association between salivary protein composition with the clinical onset/severity of oral mucositis (OM) in head and neck cancer patients treated with intensity modulated radiotherapy., Null Hypothesis: There is no association between salivary proteins and onset/severity of OM in HNC patients., (© 2024. The Author(s).)

Astringency corresponds to the sensation of dryness and roughness that is experienced in the oral cavity in association with the interaction between salivary proteins and food polyphenols. In this study, the phenolic composition of seven varietal wines, the intensity of astringency they evoke and the physicochemical reactivity of these wines with whole human saliva were evaluated. Phenolic composition of wines was characterized by spectrophotometry and HPLC chromatography. Intensity of astringency was evaluated by trained sensory panels. Saliva from a single volunteer subject was used to assess wine-saliva interactions. To this end, binary mixtures were produced at different v/v wine/saliva ratios and each of them assayed for the ability of the salivary protein to diffuse on a cellulose membrane (diffusion test) and to remain in solution (precipitation test). Physicochemical reactivities between wine components and the protein fraction of saliva were contrasted against the astringency and the phenolic profile of each varietal wine. The study supports the view that astringency depends on physicochemical interactions between two complex matrices -wine and saliva- and not between some of their particular components., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The brown planthopper (BPH) Nilaparvata lugens (Stål) is a main pest on rice. It secretes saliva to regulate plant defense responses, when penetrating rice plant and sucking phloem sap through its stylet. However, the molecular mechanisms of BPH salivary proteins regulating plant defense responses remain poorly understood. A N. lugens DNAJ protein (NlDNAJB9) gene was highly expressed in salivary glands, and the knock down of NlDNAJB9 significantly enhanced honeydew excretion and fecundity of the BPH. NlDNAJB9 could induce plant cell death, and the overexpression of NlDNAJB9 gene in Nicotiana benthamiana induced calcium signaling, mitogen-activated protein kinase (MAPK) cascades, reactive oxygen species (ROS) accumulation, jasmonic acid (JA) hormone signaling and callose deposition. The results from different NlDNAJB9 deletion mutants indicated that the nuclear localization of NlDNAJB9 was not necessary to induce cell death. The DNAJ domain was the key region to induce cell death, and the overexpression of DNAJ domain in N. benthamiana significantly inhibited insect feeding and pathogenic infection. NlDNAJB9 might interact indirectly with NlHSC70-3 to regulate plant defense responses. NlDNAJB9 and its orthologs were highly conserved in three planthopper species, and could induce ROS burst and cell death in plants. Our study provides new insights into the molecular mechanisms of insect-plant interactions., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Dental erosion is a disease of the oral cavity where acids cause a loss of tooth enamel and is defined as having no bacterial involvement. The tooth surface is protected from acid attack by salivary proteins that make up the acquired enamel pellicle (AEP). Bacteria have been shown to readily degrade salivary proteins, and some of which are present in the AEP. This study aimed to explore the role of bacteria in dental erosion using a multi-omics approach by comparing saliva collected from participants with dental erosion and healthy controls., Results: Salivary proteomics was assessed by liquid-chromatography mass spectrometry (LC-MS) and demonstrated two altered AEP proteins in erosion, prolactin inducible protein (PIP), and zinc-alpha-2 glycoprotein (ZAG). Immunoblotting further suggested that degradation of PIP and ZAG is associated with erosion. Salivary microbiome analysis was performed by sequencing the bacterial 16S rRNA gene (V1-V2 region, Illumina) and showed that participants with dental erosion had a significantly (p < 0.05) less diverse microbiome than healthy controls (observed and Shannon diversity). Sequencing of bacterial mRNA for gene expression (Illumina sequencing) demonstrated that genes over-expressed in saliva from erosion participants included H + proton transporter genes, and three protease genes (msrAB, vanY, and ppdC). Salivary metabolomics was assessed using nuclear magnetic resonance spectrometry (NMR). Metabolite concentrations correlated with gene expression, demonstrating that the dental erosion group had strong correlations between metabolites associated with protein degradation and amino acid fermentation., Conclusions: We conclude that microbial proteolysis of salivary proteins found in the protective acquired enamel pellicle strongly correlates with dental erosion, and we propose four novel microbial genes implicated in this process. Video Abstract., (© 2023. The Author(s).)

Beer is one of the most consumed beverages worldwide with unique organoleptic properties. Bitterness and astringency are well-known key features and, when perceived with high intensity, could lead to beer rejection. Most studies on beer astringency and bitterness use sensory assays and fail to study the molecular events that occur inside the oral cavity responsible for those perceptions. This work focused on deepening this knowledge based on the interaction of salivary proteins (SP) and beer phenolic compounds (PCs) and their effect toward these two sensory attributes. The astringency and bitterness of four different beers were assessed by a sensory panel and were coupled to the study of the SP changes and PC profile characterization of beers. The human SP content was measured before (basal) and after each beer intake using HPLC analysis. The beers' PC content and profile were determined using Folin-Ciocalteu and LC-MS spectrometry, respectively. The results revealed a positive correlation between PCs and astringency and bitterness and a negative correlation between SP changes and these taste modalities. Overall, the results revealed that beers with higher PC content (AAL and IPA) are more astringent and bitter than beers with a lower PC content (HL and SBO). The correlation results suggested that an increase in whole SP content, under stimulation, should decrease astringency and bitterness perception. No correlation was found between the changes in specific families of SP and astringency and bitterness perception.

Herbivorous animals that regularly consume tannin-rich food are known to secrete certain tannin-binding salivary proteins (TBSPs), especially proline-rich proteins and histidine-rich proteins, as an effective measure to counteract the antinutritive effects of dietary tannins. Due to their high binding capacity, TBSPs complex with tannins in the oral cavity, and thereby protect dietary proteins and digestive enzymes. Although the natural diet of great apes (Hominidae) is biased toward ripe fruits, analyses of food plants revealed that their natural diet contains considerable amounts of tannins, which is raising the question of possible counter-measures to cope with dietary tannins. In our study, we investigated the salivary amino acid profiles of zoo-housed Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo abelii, and compared their results with corresponding data from Homo sapiens. Individual saliva samples of 42 apes and 17 humans were collected and quantitated by amino acid analysis, using cation-exchange chromatography with postcolumn derivatization, following acid hydrolysis. We found species-specific differences in the salivary amino acid profiles with average total salivary protein concentration ranging from 308.8 mg/dL in Po. abelii to 1165.6 mg/dL in G. gorilla. Total salivary protein was consistently higher in ape than in human saliva samples (174 mg/dL). All apes had on average also higher relative proline levels than humans did. Histidine levels had the highest concentration in the samples from Po. abelii followed by P. paniscus. In all ape species, the high salivary concentrations of proline and histidine are considered to be indicative of high concentrations of TBSPs in hominids. Given that the species differences in salivary composition obtained in this study correspond with overall patterns of secondary compound content in the diet of wild populations, we assume that salivary composition is resilient to acute and long-lasting changes in diet composition in general and tannin content in particular., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: To evaluate and compare the proteomic profile of acquired pellicle on smooth bovine tooth and tooth-coloured restorative materials, including resin composite (RC), glass ionomer cement (GIC), and casein phosphopeptide-amorphous calcium phosphate modified GIC (CPP-ACP GIC)., Methods: Two-hour in situ pellicles on tooth/materials specimens mounted in oral appliances worn by ten healthy adults were investigated. Pellicle proteins and corresponding unstimulated whole saliva were quantitatively analysed through liquid chromatography-tandem mass spectrometry., Results: Significantly higher amounts of protein were adsorbed onto tooth surface than restorative materials tested (4.11 ± 0.69 vs. 2.54 ± 0.38/2.98 ± 0.80/3.01 ± 0.37 µg, RC/GIC/CPP-ACP GIC). From the ten participants, 1,444 (487-1,086/person), 1,454 (645-1,051/person), 1,731 (454-1,475/person), or 1,597 (423-1,261/person) pellicle proteins were detected at least once on bovine tooth, RC, GIC, or CPP-ACP GIC, respectively, and with 1,072 (304-793/person) salivary proteins identified. Comparative quantification revealed minor differences between tooth and restorative materials pellicle profiles. High inter-individual variations in pellicle protein composition were demonstrated. Compared to the salivary protein profile, 214/57 proteins showed significantly increased/decreased abundance in pellicle formed on at least one substrate (fold change > 3.325/fold change < 0.301). Gene Ontology enrichment analysis showed some pellicle proteins detected with increased affinity to tooth/material surface were identified as being related to "calcium-dependent protein binding" or "cell-cell adhesion mediator activity"., Conclusion: Similar protein quantity and composition was observed in 2 h in situ pellicles formed on different smooth restorative material surfaces. The proteomic profile of pellicles appeared distinct from that of the corresponding unstimulated whole saliva., Clinical Significance: Host backgrounds appeared more influential on the proteomic profile of the in situ acquired pellicle than the underlying substrate characteristics among systemically and orally healthy adults. Pellicle proteins preferentially adsorbed on tooth/materials were putatively associated with calcium ion homeostasis or host-microbiota interaction., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Radiation therapy leads to salivary gland damage that causes xerostomia, the standard radiation-induced complication during radiotherapy that affects the quality of life in head and neck cancer patients. This study was conducted at a tertiary cancer institute in Punjab state to analyze the influence of radiation therapy on various parameters and substances of saliva., Materials and Methods: Sixty head and neck cancer patients who underwent conventional radiotherapy on a Cobalt machine were included. Saliva was collected in both stimulated and unstimulated states. Stimulated whole saliva was collected by applying two to three drops of citric acid solution (2%) over the dorsum of the tongue bilaterally at 30-s intervals for 2 min. Biochemical changes in the whole saliva were evaluated by biochemical methods at baseline, completion of therapy, and 3 and 6 months post-radiotherapy completion., Results: The lowest concentration of proteins was seen after the therapy in unstimulated and stimulated saliva. Salivary protein levels showed a rising trend toward baseline in 3- and 6-month posttherapy samples. The peak value (0.4 mg/dl) was reached in the stimulated saliva after therapy. Salivary amylase did not show a consistent concentration graph. The salivary concentrations of sodium, potassium, and chloride showed peak values after radiotherapy. The lowest salivary pH was obtained at completion of therapy, both in unstimulated and stimulated saliva. After 3 months of chemoradiotherapy, the saliva reached a pH value of 8.3, whereas 6-month posttherapy sample showed a pH value of 8.4 in both unstimulated and stimulated saliva., Conclusions: At the completion of chemoradiotherapy, the total salivary protein, albumin, and inorganic components (calcium, magnesium, phosphorus) showed a downward trend from the baseline values due to the damage caused to the acinar part of the salivary gland by radiotherapy. The rise in salivary electrolytes' concentrations is attributed to the fact that even though there is loss of absorptive property of the tubular portion of the salivary gland, it retains its secretory property. Saliva becomes thick, scarce, tenacious, and acidic during the period of chemoradiotherapy., (Copyright © 2023 Copyright: © 2023 Journal of Cancer Research and Therapeutics.)

Objectives: This study aimed to characterise diurnal dynamics of salivary peptidome and variations induced by sampling procedures., Materials and Methods: A supervised short-term longitudinal study was conducted amongst ten healthy participants. Saliva samples were collected by different procedures (stimulated/unstimulated conditions, forepart/midstream segments) on three consecutive days. The peptidome compositions of saliva samples were analysed using matrix-assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-TOF MS)., Results: The salivary peptidome exhibited a stable trend generally, even though some diurnal dynamics happened in aspects of both overall structure and certain single peptides. The results indicated saliva samples collected under unstimulated and stimulated conditions have significantly different structures of peptidome, whilst the peptidome profile of stimulated saliva was more abundant than that of unstimulated saliva. It was also indicated that the midstream segment effect might exist in the segmented process of saliva sampling., Conclusions: In summary, salivary peptidome was able to maintain stability though some dynamic changes might happen within a short-term period. Stimulated and unstimulated saliva samples had significantly different peptidome profiles, whilst the stimulated whole saliva was a larger pool of low molecular weight peptides., Clinical Relevance: The stability of the salivary peptidome highlights the reliability of salivary peptidome as a source of diagnostic biomarker. We recommend keeping one collection condition (stimulated/unstimulated) consistently within one study on salivary peptidome. Stimulated whole saliva would be preferred if more abundant peptidome profile is needed., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Tannins are a chemical defense mechanism of plants consumed by herbivores. Variations in salivary physicochemical characteristics such as pH, total protein concentration (TP), and presence of proline-rich proteins (PRPs) in animals have been reported as a mechanism to protect the oral cavity when consuming food with variations in pH and tannins. Variations in salivary physiochemistry as adaptations for consuming tannin-rich foods have been found in omnivorous and folivorous primates, but have not yet been reported in frugivorous species such as spider monkeys. We therefore assessed changes in pH using test strips, TP concentration by measuring absorbance at 595 nm in a spectrophotometer and salivary PRPs using the SDS-PAGE electrophoresis technique in the saliva of nine captive spider monkeys in response to the consumption of solutions with different concentrations of tannic acid. The results showed variations in pH, TP concentration and the presence and variation of possible salivary PRPs associated with tannic acid concentration. These findings suggest that spider monkeys may tailor their salivary physicochemical characteristics in response to the ingestion of potentially toxic compounds., Competing Interests: The authors declare that they have no competing interests., (© 2022 Torres et al.)

Studying protein localization in mosquito salivary glands provides novel insights on the function and physiological relevance of salivary proteins and also provides an avenue to study interactions between mosquitoes and pathogens. Salivary proteins display compartmentalization. For example, proteins involved in blood feeding are stored in the medial and distal lateral lobes, whereas proteins related to sugar metabolism localize to the proximal portion of the lateral lobes. Immunohistochemistry assays use antibodies raised against recombinant salivary proteins to reveal the protein localization and interactions within the tissue. In this assay, permeabilization of the salivary glands allows the antibodies to enter the cells and bind their target proteins. The primary antibody-antigen complexes are later marked with fluorescently labeled secondary antibodies. Antibodies that recognize pathogen-specific proteins can also be incorporated in these assays, providing information about pathogen localization within the salivary glands or pathogen interactions with mosquito salivary proteins. Here, we introduce immunohistochemistry assays for use in mosquito salivary glands., (This is a work of the US government.)

The interaction of emulsions with the tongue is key to the sensory appeal of food and can potentially be exploited for oral/buccal pharmaceutical delivery. Whilst there is good understanding of the different mucoadhesive forces governing emulsion interaction with the tongue, their relative importance is not well understood. In addition, the physical location of emulsions within the saliva papillae on the tongue is not understood at all. A combination of ex vivo salivary film, and in vivo oral coating experiments were used to determine the importance of different mucoadhesive forces. Mucoadhesion of cationic emulsions was largely driven by electrostatic complexation. SDS-PAGE of the in vivo saliva coating highlighted that mucins were largely responsible for cationic emulsion mucoadhesion. Anionic emulsions were bound via hydrophobic/steric interactions to small salivary proteins typically located away from the mucin anchor points. The physical location and clustering of emulsions relative to the salivary film/papillae was probed via the invention of a fluorescent oral microscope. Cationic emulsions were densely clustered close to the papillae whilst anionic emulsions were suspended in the salivary film above the papillae. Interestingly, non-ionic emulsions were also trapped within the salivary film above the papillae as individual droplets. These findings highlight that whilst electrostatic complexation with saliva is a powerful mucoadhesive force, hydrophobic and steric interactions also act to induce oral retention of emulsions. The differences in physical location and clustering of emulsions within the salivary film hint at the 3D locations of the different salivary proteins driving each mucoadhesive interaction. This novel understanding of emulsion saliva/papillae interactions has potential to aid efficacy of buccal pharmaceutical delivery and the reduction of astringency in plant-based foods., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)

The oral cavity remains an underappreciated site for SARS-CoV-2 infection despite the myriad oral conditions observed in COVID-19 patients. Recently, replicating SARS-CoV-2 was found inside salivary epithelial cells resulting in inflammation and atrophy of salivary glands. Saliva possesses healing properties crucial for maintaining the health of the oral mucosa. Specifically, salivary antimicrobial peptides, most notable, histatin-5 exclusively produced in salivary glands, plays a vital role in innate immunity against colonizing microbial species. The demonstration of SARS-CoV-2 destruction of gland tissue where histatin-5 is produced strongly indicate that histatin-5 production is compromised due to COVID-19. Here we present a case of a patient presenting with unexplained chronic oral dysesthesia and dysgeusia post-recovery from COVID-19. To explore potential physiological mechanisms behind the symptoms, we comparatively analyzed saliva samples from the patient and matched healthy subject for histatin-5 and key cytokines. Findings demonstrated significantly reduced histatin-5 levels in patient's saliva and activation of the Th17 inflammatory pathway. As histatin-5 exhibits potent activity against the opportunistic oral pathogen Candida albicans , we evaluated saliva potency against C. albicans ex vivo . Compared to control, patient saliva exhibited significantly reduced anti-candidal efficacy. Although speculative, based on history and salivary analysis we hypothesize that salivary histatin-5 production may be compromised due to SARS-CoV-2 mediated salivary gland destruction. With the current lack of emphasis on implications of COVID-19 on oral health, this report may provide lacking mechanistic insights that may lead to reassessment of risks for oral opportunistic infections and mucosal inflammatory processes in acutely-ill and recovered COVID-19 patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Alfaifi, Sultan, Montelongo-Jauregui, Meiller and Jabra-Rizk.)

Allergic disease has risen to epidemic proportions since the last decade and is among the most common noncommunicable, chronic diseases in children and adolescents worldwide. Allergic disease usually occurs in early life; thus, early biomarkers of allergic susceptibility are required for preventive measures to high-risk infants which enable early interventions to decrease allergic severity. However, to date, there is no reliable general or specific allergy phenotype detection method that is easy and noninvasive for children. Most reported allergic phenotype detection methods are invasive, such as the skin prick test (SPT), oral food challenge (OFC), and blood test, and many involve not readily accessible biological samples, such as cord blood (CB), maternal blood, or newborn vernix. Saliva is a biological sample that has great potential as a biomarker measurement as it consists of an abundance of biomarkers, such as genetic material and proteins. It is easily accessible, noninvasive, collected via a painless procedure, and an easy bedside screening for real-time measurement of the ongoing human physiological system. All these advantages emphasise saliva as a very promising diagnostic candidate for the detection and monitoring of disease biomarkers, especially in children. Furthermore, protein biomarkers have the advantages as modifiable influencing factors rather than genetic and epigenetic factors that are mostly nonmodifiable factors for allergic disease susceptibility in childhood. Saliva has great potential to replace serum as a biological fluid biomarker in diagnosing clinical allergy. However, to date, saliva is not considered as an established medically acceptable biomarker. This review considers whether the saliva could be suitable biological samples for early detection of allergic risk. Such tools may be used as justification for targeted interventions in early childhood for disease prevention and assisting in reducing morbidity and mortality caused by childhood allergy., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 N. H. M. Zainal et al.)

Background: There is an urgent need for new, accurate, rapid, and affordable tuberculosis (TB) diagnostic tests. The aim of the present study was to use mass spectrometry to identify new preliminary candidate TB diagnostic protein biomarkers in saliva obtained from individuals with TB, and patients with other respiratory diseases (ORD)., Methods: Saliva samples were collected from 22 individuals who self-presented with symptoms suggestive of TB as part of a larger TB biomarker project. Purified salivary proteins were subjected to tryptic digestion peptides were analyzed using a QExactive Orbitrap Mass Spectrometer. Data are available via ProteomeXchange with identifier PXD027294. Identified proteins were subjected to gene ontology and ingenuity pathway analysis for functional enrichment analysis., Results: 26 of the 652 identified proteins significantly discriminated individuals with TB from those with ORD after Benjamini Hochberg correction (5% FDR), with five of these proteins diagnosing TB with an AUC ≥ 0.80. A 5-protein biosignature comprising of P01011, Q8NCW5, P28072, A0A2Q2TTZ9, and Q99574 diagnosed TB with an AUC of 1.00 (95% CI, 1.00-1.00), sensitivity of 100% (95% CI, 76.2-100%) and specificity of 90.9% (95% CI, 58.7-99.8%) after leave-one-out cross validation., Conclusions: We identified novel candidate salivary protein biomarkers and biosignatures with strong potential as TB diagnostic candidates. Our results are preliminary and require validation in larger studies., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Plant Growth-Promoting Rhizobacteria (PGPR) induce systemic resistance (SR) in plants, decreasing the development of phytopathogens. The FZB42 strain of Bacillus velezensis is known to induce an SR against pathogens in various plant species. Previous studies suggested that it could also influence the interactions between plants and associated pests. However, insects have developed several strategies to counteract plant defenses, including salivary proteins that allow the insect escaping detection, manipulating defensive pathways to its advantage, deactivating early signaling processes, or detoxifying secondary metabolites. Because Brown Marmorated Stink Bug (BMSB) Halyomorpha halys is highly invasive and polyphagous, we hypothesized that it could detect the PGPR-induced systemic defenses in the plant, and efficiently adapt its salivary compounds to counteract them. Therefore, we inoculated a beneficial rhizobacterium on Vicia faba roots and soil, previous to plant infestation with BMSB. Salivary gland proteome of BMSB was analyzed by LC-MS/MS and a label-free quantitative proteomic method. Among the differentially expressed proteins, most were up-regulated in salivary glands of insects exposed to PGPR-treated plants for 24 h. We could confirm that BMSB was confronted with a stress during feeding on PGPR-treated plants. The to-be-confirmed defensive state of the plant would have been rapidly detected by the invasive H. halys pest, which consequently modified its salivary proteins. Among the up-regulated proteins, many could be associated with a role in plant defense counteraction, and more especially in allelochemicals detoxification or sequestration., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Saliva provides a primary defense mechanism against several infectious diseases through its numerous immunological and non-immunological factors. Alteration in the composition of saliva often compromises its defense mechanisms, predisposing the oral cavity to disease entities. HIV patients under antiretroviral therapy (ART) have shown to exhibit altered salivary composition. These changes are postulated to be a result of the effect of ART on the salivary protein and electrolytes levels., Objectives: The present study aims to assess the potential difference in the salivary total protein and electrolyte levels in HIV patients with and without ART., Methods: Patients were divided into 3 groups- Group A (HIV-1 positive patient under ART for at least 6 months)-66, Group B (HIV-1 positive patient not started on ART)-66, Group C (HIV negative patients)-66. Saliva samples were collected and evaluated for total salivary protein and electrolyte levels in all the 3 groups., Results: There was a statistically significant difference in the salivary protein (p = 0.000) and electrolyte (Sodium, p = 0.000; Potassium, p = 0.039; chlorine, p = 0.027; ionized calcium, p = 0.002) levels among the three groups., Conclusion: HIV positive individuals with and without ART have alteration in the salivary composition. Some of these alterations (total protein and iCa levels) are due to the HIV infection, while others (Na, K, Cl) could be due to ART or a combined effect of both. Salivary changes in HIV positive individuals could predispose them to oral diseases. Thus, regular oral examination and prophylactic regimen must be formulated to maintain their oral hygiene and quality of life., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest, (Copyright © 2021. Published by Elsevier Inc.)

Background: The argasid tick Ornithodoros moubata is the main vector in mainland Africa of African swine fever virus and the spirochete Borrelia duttoni, which causes human relapsing fever. The elimination of populations of O. moubata would contribute to the prevention and control of these two serious diseases. Anti-tick vaccines are an eco-friendly and sustainable means of eliminating tick populations. Tick saliva forms part of the tick-host interface, and knowledge of its composition is key to the identification and selection of vaccine candidate antigens. The aim of the present work is to increase the body of data on the composition of the saliva proteome of adult O. moubata ticks, particularly of females, since in-depth knowledge of the O. moubata sialome will allow the identification and selection of novel salivary antigens as targets for tick vaccines., Methods: We analysed samples of female and male saliva using two different mass spectrometry (MS) approaches: data-dependent acquisition liquid chromatography-tandem MS (LC-MS/MS) and sequential window acquisition of all theoretical fragment ion spectra-MS (SWATH-MS). To maximise the number of proteins identified, a proteomics informed by transcriptomics analysis was applied using the O. moubata salivary transcriptomic dataset previously obtained by RNA-Seq., Results: SWATH-MS proved to be superior to LC-MS/MS for the study of female saliva, since it identified 61.2% more proteins than the latter, the reproducibility of results was enhanced with its use, and it provided a quantitative picture of salivary components. In total, we identified 299 non-redundant proteins in the saliva of O. moubata, and quantified the expression of 165 of these in both male and female saliva, among which 13 were significantly overexpressed in females and 40 in males. These results indicate important quantitative differences in the saliva proteome between the sexes., Conclusions: This work expands our knowledge of the O. moubata sialome, particularly that of females, by increasing the number of identified novel salivary proteins, which have different functions at the tick-host feeding interface. This new knowledge taken together with information on the O. moubata sialotranscriptome will allow a more rational selection of salivary candidates as antigen targets for tick vaccine development., (© 2021. The Author(s).)

Taste plays an important role in processes such as food choices, nutrition status and health. Salivary proteins contribute to taste sensitivity. Taste reduction has been associated with obesity. Gender influences the obesity predisposition and the genetic ability to perceive the bitterness of 6- n -propylthiouracil (PROP), oral marker for food preferences and consumption. We investigated variations in the profile of salivary proteome, analyzed by HPLC-ESI-MS, between sixty-one normal weight subjects (NW) and fifty-seven subjects with obesity (OB), based on gender and PROP sensitivity. Results showed variations of taste-related salivary proteins between NW and OB, which were differently associated with gender and PROP sensitivity. High levels of Ps-1, II-2 and IB-1 proteins belonging to basic proline rich proteins (bPRPs) and PRP-1 protein belonging to acid proline rich proteins (aPRPs) were found in OB males, who showed a lower body mass index (BMI) than OB females. High levels of Ps-1 protein and Cystatin SN (Cyst SN) were found in OB non-tasters, who had lower BMI than OB super-tasters. These new insights on the role of salivary proteins as a factor driving the specific weight gain of OB females and super-tasters, suggest the use of specific proteins as a strategic tool modifying taste responses related to eating behavior.

Aims: To investigate novel biomarker for diagnosis of cervical cancer, we analyzed the datasets in Gene Expression Omnibus (GEO) and confirmed the candidate biomarker in patient sample., Materials and Methods: We collected major datasets of cervical cancer in GEO, and analyzed the differential expression of normal and cancer samples online with GEO2R and tested the differences, then focus on the GSE63514 to screen the target genes in different histological grades by using the R-Bioconductor package and R-heatmap. Then human specimens from the cervix in different histological grades were used to confirm the top 8 genes expression by immunohistochemical staining using Ki67 as a standard control., Results: We identified genes differentially expressed in normal and cervical cancer, 274 upregulated genes and 206 downregulated genes. After intersection with GSE63514, we found the obvious tendency in different histological grades. Then we screened the top 24 genes, and confirmed the top 8 genes in human cervix tissues. Immunohistochemical (IHC) results confirmed that keratin 17 (KRT17) was not expressed in normal cervical tissues and was over-expressed in cervical cancer. Cysteine-rich secretory protein-2 (CRISP2) was less expressed in high-grade squamous intraepithelial lesions (HSILs) than in other histological grades., Conclusion: For the good repeatability and consistency of KRT17 and CRISP2, they may be good candidate biomarkers. Combined analysis of KRT17, CRISP2 expression at both genetic and protein levels can determine different histological grades of cervical squamous cell carcinoma. Such combined analysis is capable of improving diagnostic accuracy of cervical cancer., (© 2021 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Abstract: The purpose of the present study was to investigate the accuracy of a screening method using salivary tests to screen for periodontal disease.In total, 1888 individuals older than 30 years in 2017 and 2296 in 2018 who underwent medical check-ups for metabolic syndrome agreed to participate and simultaneously underwent a dental examination by dentists and salivary tests. Salivary occult blood, protein, and ammonia levels and white blood cell counts were evaluated in salivary tests using commercially available kits. The relationship between the results of the salivary tests and dental examination was examined and classification performance was analyzed.The prevalence of periodontal disease was 69.9% in 2017 and 66.8% in 2018. Salivary ammonia showed the highest classification performance in both years (sensitivity 83.5 and 83.1%, precision 73.0 and 69.3%, F-measure 0.779 and 0.756). Occult blood, which was assessed using a monoclonal antibody to human hemoglobin, also showed good performance (sensitivity 69.5%, precision 70.6%, F-measure 0.701). Questions regarding self-reported gingival bleeding were not sufficient to screen for periodontitis. The present results suggest that screening tests using salivary samples may detect periodontal disease in approximately 70% to 80% of subjects in a large population.Conclusion: Salivary ammonia and hemoglobin have potential as salivary markers in the screening of periodontal disease., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Salivary proteomic analysis may help to understand physiopathological changes in crack cocaine dependents. This study aimed to compare the salivary protein profile between crack cocaine dependents and non-drug users., Design: Nine heavy smokers and alcohol consumers men admitted to rehab due to crack cocaine abuse and nine non-drug users age-matched men were evaluated. Unstimulated whole saliva was collected. Proteomic analysis was performed by mass spectrometer. Data were processed using ProteinLynx GlobalServer software. Results were obtained by searching the Homo sapiens database from the UniProt catalog. The search tool IBI-IMIM was used to identify proteins candidates for biomarkers., Results: The mean age of crack cocaine and control groups was 36.89 ± 7.78 and 35.78 ± 6.68 years, respectively. 458 salivary proteins were identified in both groups; 305 proteins in the crack cocaine group. Among the 68 proteins presented in both groups, 29 were down-regulated (i.e. "Statherin" and "Transforming growth factor-beta-induced protein ig-h3" were down-regulated at least 10-fold) and 27 up-regulated (i.e. "Negative elongation factor" was up-regulated 19-fold) in the crack cocaine group compared to controls. 90 out of the 458 proteins found in the proteomic analysis were identified as candidates for biomarkers of diseases. Among these, 65 (72.22 %) were detected in the crack cocaine group., Conclusion: Crack cocaine dependents with chronic alcohol and tobacco use have a higher number of proteins in saliva compared to non-drug users. 22.3 % of salivary proteins present in crack cocaine dependents were present in controls; 3.9 % of them were expressed in similar quantity., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Aims: To investigate the immunoglobulin (Ig) G response after being fed upon by Cimex lectularius L., Methods and Results: Participants were fed upon by three male C lectularius insects weekly for a month. Blood was obtained before the feeding and at the last feeding, which was used for immunoblots against bed bug salivary gland extract, with antihuman Immunoglobulin G (IgG) secondary antibodies. No consistent IgG changes developed in 11 humans serially fed upon by C lectularius. Two participants had new IgG responses to proteins at molecular weights of approximately 12-13 kDa, and one had an IgG response to a protein at approximately 40 kDa. At the last study visit, more intense IgG bands to proteins at molecular weights of 12-13 kDa had developed in 55% of participants (6/11) and at molecular weights of ≈30, ≈40 and ≈70 kDa in 45% (5/11) compared with the first study visit. Nitrophorin and apyrase were the most common C lectularius proteins identified with liquid chromatography-tandem mass spectrometry in both crushed bed bug salivary gland extract and post-bed bug feeding extract., Conclusions: Human participants did not have consistent IgG responses to crushed C lectularius salivary gland extract., (© 2020 John Wiley & Sons Ltd.)

Utilising biomarkers for COVID-19 diagnosis, prediction of treatment response and overall prognostication have been investigated recently. However, these ventures have only considered the use of blood-based molecular markers. Saliva is another biofluid that warrants being applied in similar fashion with major advantages that centres on its non-invasive and repeatable collection as well as cost-efficiency. To this end, this article presents a hypothesis for the sources of biomarkers useful clinically for COVID-19 disease outcome estimation and identify the likely implications of their detection in saliva., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Dogs' saliva is a complex mixture of inorganic and organic constituents, rich in proteins. Therefore, knowing the saliva composition of these animals is extremely important to identify the presence of proteins that may be involved in physiological and pathological mechanisms of their oral cavity. The present study aimed to characterize the proteomic profile of saliva from dogs with and without dental calculus., Results: Saliva samples were collected from 20 dogs. Before the collection, a visual clinical examination was performed and 8 subjects (40%) did not present any signs of dental calculus, while 12 (60%) presented dental calculus. After saliva collection, the samples were submitted to protein quantification (mBCA), and then they were prepared for analysis by nLC-ESI-MS/MS. A total of 658 unique proteins were identified, of which 225 were specific to dogs without dental calculus, 300 were specific to dogs with dental calculus, and 133 were common to all subjects. These proteins presented functions including transportation, immune response, structural, enzymatic regulation, signal transduction, transcription, metabolism, and some proteins perform functions as yet unknown. Several salivary proteins in dogs with dental calculus differed from those found in the group without dental calculus. Among the abundant proteins detected in periodontal affected cases, can be highlighting calcium-sensing receptor and transforming growth factor beta. Enrichment analysis reveled the presence of Rho GTPases signaling pathway., Conclusions: This research identified salivary proteins, that should be further investigated as potencial biomarkers of chronic periodontits with dental calculus formation in dogs.

The interaction between wine tannins and saliva proteins is responsible for wine astringency perception, producing a depletion of salivary proteins and changes on oral friction. In sensorial terms, astringency is described as a dryness and puckering sensation in the mouth, which is related to the "structure" or "body" of red wines. However, these last descriptors, as structure or body, are perceived during wine tasting and commonly related to wine viscosity. To address these differences on sensory response, we hypothesize that tannin-protein interactions could be a key factor involved in the viscosity of red wines/saliva mixtures, just as they are for astringency. We used a rheological method to study the impact of tannin-protein interaction on the viscosity of model wine-saliva systems. Mixtures of model saliva based on mucin and typical astringent compounds, as commercial tannins and gallic acid, were evaluated for their rheological behavior. The viscometric flow of the fluid mixtures was determined, and subsequently, the viscosity was evaluated at a shear rate of 60 s -1 . It was observed that red wines/saliva mixtures exhibit non-Newtonian flow and ascending tannin doses led to an increase in the apparent viscosity. Nephelometric analysis demonstrate that tannin-mucin aggregates were formed, which suggests that these complexes were potentially responsible for the viscosity increases, modifying the rheological behavior of these mixtures. Results from this work propose that tannin-protein interactions are also involved in the underlying mechanism of thickness perception of red wines and rheology could be a complementary instrumental technique for wine mouthfeel characterization., (© 2020 Wiley Periodicals, Inc.)

Introduction: Rhodnius (Hemiptera: Reduviidae: Triatominae) species are made up of haematophagous insect vectors for Trypanosoma cruzi (Chagas’ disease aetiological agent) and T. rangeli, an infective parasite that is not pathogenic for vertebrate hosts. The study of their salivary protein diversity enables the obtention of characteristic one-dimensional electrophoretic profiles of some triatomine species; however, few reports have dealt with Rhodnius species salivary proteins electrophoretic patterns. Objective: To compare R. colombiensis, R. pallescens, R. pictipes, R. prolixus, and R. robustus’ salivary proteins one-dimensional electrophoretic profiles. Materials and methods: SDS-PAGE was used for obtaining electrophoretic profiles of saliva from the species under study. The unweighted pair group method with arithmetic mean (UPGMA) was used for constructing a phenogram. Results: Electrophoretic profiles of soluble saliva had protein bands ranging from 15 to 45 kDa, thereby enabling the five species studied to be differentiated. The phenogram revealed two main groups, one formed by the Pictipes and Prolixus cis-Andean groups and another consisting of the Pallescens trans-Andean group. Conclusion: Differences were revealed regarding R. colombiensis, R. pallescens, R. pictipes, R. prolixus, and R. robustus electrophoretic profiles of salivary proteins; their variability facilitated constructing a phenogram which was taxonomically congruent with the groups from the genus Rhodnius.

Background: Saliva is a complex secretion produced daily by the salivary glands. Saliva consists mainly of water, enzymes, ions and amino acids and performs several important functions in oral health., Objective: The aim of this study was to investigate the flow rate and concentrations of amylase and total proteins in the saliva of hospitalized patients due to AIDS complications., Methods: Ninety-three men and women (20-64 years of age) were divided into two groups (46 HIV-infected patients and 47 controls) and had salivary flow rate and levels of amylase enzyme and total proteins evaluated., Result: The mean salivary flow rate was lower in individuals with HIV when compared to controls (P < 0.05). No significant difference between amylase enzyme levels and total proteins were observed in the saliva of patients with HIV infection when compared to controls., Conclusion: Individuals with HIV / AIDS infection (in hospital treatment) suffer no interference in levels of amylase and total salivary proteins, but they have significantly reduced salivary flow., (© 2020 Carina de Oliveira N et al.)

Objectives: Opiorphin is a physiological inhibitor of peptidases inactivating endogenous opioids displaying strong analgesic properties without undesirable side effects, antidepressant properties or hormonal dependency. It might therefore play an important role in patients with painful diseases related to neuro-hormonal dysregulation of the nervous system, affecting saliva secretion and composition such as anorexia nervosa (AN). The main objective aim of this study was to compare the level of opiorphin in saliva of patients with AN to matched subjects free of eating disorders. Methods: A case-control clinical trial was conducted in 68 AN patients and 43 healthy matched control subjects. Depression symptoms were assessed with the self-scored questionnaire Beck Depression Inventory (BDI) and salivary samples were taken during the acute stage of AN (BMI <15 kg/m 2 ) for measuring opiorphin. Opiorphin levels were measured with a quantitative assay using a commercial immunoenzymatic Elisa kit (cat no. EH1927, Wuchan, Hubei, China). Results: No statistically significant difference was found in salivary opiorphin levels between the AN and control groups, ( P  = 0.499, Mann-Whitney U -test). Positive correlations to duration of the disease, BDI and bodyweight in AN patients were evidenced. Conclusions: Measurement of salivary opiorphin levels cannot be used as a marker of AN but may allow new perspectives in monitoring AN in its early stages.

Proteins in saliva are needed for preprocessing food in the mouth, maintenance of tooth mineralization, and protection from microbial pathogens. Novel insights into human lineage-specific functions of salivary proteins and clues to their involvement in human disease can be gained through evolutionary studies, as recently shown for salivary amylase AMY1 and salivary agglutinin DMBT1/gp340. However, the entirety of proteins in saliva, the salivary proteome, has not yet been investigated from an evolutionary perspective. Here, we compared the proteomes of human saliva and the saliva of our closest extant evolutionary relatives, chimpanzees and gorillas, using macaques as an outgroup, with the aim to uncover features in saliva protein composition that are unique to each species. We found that humans produce a waterier saliva, containing less than half total protein than great apes and Old World monkeys. For all major salivary proteins in humans, we could identify counterparts in chimpanzee and gorilla saliva. However, we discovered unique protein profiles in saliva of humans that were distinct from those of nonhuman primates. These findings open up the possibility that dietary differences and pathogenic pressures may have shaped a distinct salivary proteome in the human lineage., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

Saliva contains possible biomarkers that are associated with dental caries. The present study aimed to analyse differences in the abundance of proteins in the saliva between caries-positive (CP; N = 15) and caries-free (CF; N = 12) males and to compare differences in the abundance of proteins between two saliva sample fractions (supernatant and pellet). We found 14 differently significantly expressed proteins in the CF group when comparing the supernatant fractions of the CP and CF groups, and three proteins in the pellet fractions had significantly higher expression in the CP group. Our results indicate very specific protein compositions of the saliva in relation to dental caries resistance (the saliva of the CP group mainly contained pellet proteins and the saliva of the CF group mainly contained supernatant proteins). This was the first time that the saliva pellet fraction was analysed in relation to the dental caries status. We detected specific calcium-binding proteins that could have decalcified enamel in the saliva pellet of the CP group. We also observed significantly up-regulated immune proteins in the saliva supernatant of the CF group that could play an important role in the caries prevention. The particular protein compositions of the saliva pellet and supernatant in the groups with different susceptibilities to tooth decay is a promising finding for future research.

New Findings: What is the central question of this study? What are the relationships between physical properties of saliva, protein composition and metabolite composition? What is the main finding and its importance? Salivary citrate, one of the major endogenous metabolites in saliva, increased upon capsaicin stimulation and was associated with improved physical properties measured by extensional rheology. This suggests salivary gland citrate transporters might be a valuable area of future study., Abstract: Saliva displays viscoelastic properties which enable coating, lubrication and protection of the oral mucosa and hard tissues. Individuals lacking saliva or perceiving oral dryness can manage their symptoms using artificial saliva preparations, but these often fail to mimic the sensation and functionality of natural saliva. It is widely acknowledged that mucins (MUC7 and MUC5B) confer saliva's rheological properties, but artificial saliva containing purified mucins is still often an inadequate substitute. This work aimed to explore salivary components that influence salivary extensional rheology to better understand how natural saliva could be replicated. Saliva was stimulated via control and capsaicin solutions in healthy volunteers. Extensional rheology was analysed using a CaBER-1 (capillary breakup) extensional rheometer. Protein composition, including mucins, was measured by gel-electrophoresis band densitometry and metabolites were measured by 1 H nuclear magnetic resonance spectroscopy. Capsaicin stimulation significantly increased capillary breakup time, extensional viscosity and the abundance of most major salivary proteins. Stimulation also increased salivary citrate and choline concentrations. Significant correlations were found between capillary breakup time and amylase (r = 0.67, P < 0.05), statherin (ρ = 0.66, P < 0.05) and citrate (ρ = 0.81, P < 0.01). The relationship between citrate and salivary rheology was subsequently investigated in vitro. These results suggest that citrate and non-mucin proteins are stronger predictors of salivary rheology than the more often studied mucin glycoproteins. Potential mechanisms are discussed and future work in this area could help formulate more effective saliva substitutes, more closely resembling natural saliva., (© 2019 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

The burrower bug Scaptocoris castanea Perty, 1830 (Hemiptera: Cydnidae) is an agricultural pest feeding on roots of several crops. The histology and ultrastructure of the salivary glands of S. castanea were described. The salivary system has a pair of principal salivary glands and a pair of accessory salivary glands. The principal salivary gland is bilobed with anterior and posterior lobes joined by a hilus where an excretory duct occurs. The accessory salivary gland is tubular with a narrow lumen that opens into the hilus near the excretory duct, suggesting that its secretion is stored in the lumen of the principal gland. The cytoplasm of the secretory cells is rich in the rough endoplasmic reticulum, secretory vesicles with different electron densities and mitochondria. At the base of the accessory gland epithelium, there were scattered cells that do not reach the gland lumen, with the cytoplasm rich in the rough endoplasmic reticulum, indicating a role in protein production. Data show that principal and accessory salivary glands of S. castanea produce proteinaceous saliva. This is the first morphological description of the S. castanea salivary system that is similar to other Hemiptera Pentatomomorpha, but with occurrence of basal cells in the accessory salivary gland.

Screening for systolic heart failure (SHF) has been problematic. Heart failure management guidelines suggest screening for structural heart disease and SHF prevention strategies should be a top priority. We developed a multi-protein biomarker panel using saliva as a diagnostic medium to discriminate SHF patients and healthy controls. We collected saliva samples from healthy controls (n = 88) and from SHF patients (n = 100). We developed enzyme linked immunosorbent assays to quantify three specific proteins/peptide (Kallikrein-1, Protein S100-A7, and Cathelicidin antimicrobial peptide) in saliva samples. The analytical and clinical performances and predictive value of the proteins were evaluated. The analytical performances of the immunoassays were all within acceptable analytical ranges. The multi-protein panel was able to significantly ( p < 0.001) discriminate saliva samples collected from patients with SHF from controls. The multi-protein panel demonstrated good performance with an overall diagnostic accuracy of 81.6% (sensitivity of 79.2% and specificity of 85.7%) when distinguishing SHF patients from healthy individuals. In conclusion, we have developed immunoassays to measure the salivary concentrations of three proteins combined as a panel to accurately distinguish SHF patients from healthy controls. While this requires confirmation in larger cohorts, our findings suggest that this three-protein panel has the potential to be used as a biomarker for early detection of SHF.

Background: Alcohol and substances found in tobacco may alter salivary flow and amount of saliva proteins. This study aimed to compare salivary proteins between alcohol dependent smokers and controls., Methods: This is a case-control study with men older than 18 years of age, matched by age. The alcohol-dependent group was composed by heavy smokers and alcohol consumers. Unstimulated whole saliva was collected from all subjects. Analysis of digested peptides was performed in mass spectrometer. Data were processed using ProteinLynx GlobalServer software. Results were obtained by searching theHomo sapiens database from the UniProt catalog. The search tool IBI-IMIM was used to identify candidate proteins for biomarkers., Results: Alcohol-dependent and control groups were composed of nine participants each, with mean age of 36.89 ± 2.57 and 35.78 ± 1.64 years, respectively. 404 salivary proteins were found in both groups; 282 in the alcohol-dependent. Among the 96 proteins presented in both groups, 32 were up-regulated in the alcohol dependents (i.e. "Hemoglobin subunit beta" and "Forkhead box protein P2" were up-regulated at least 10-fold), 23 were down-regulated (i.e. "Statherin" and "RNA-binding protein 25" were down-regulated at least 10-fold), and 41 presented similar expression in both groups. 71 proteins were candidates for biomarkers of disorders 58 presented in alcohol dependents' saliva. The most common disorders were neoplasms, genetic, cardiovascular, metabolic and glandular diseases., Conclusions: Salivary protein profile undergoes strong changes in alcohol and tobacco dependents. 34% of salivary proteins present in alcohol and tobacco dependents were present in controls; 14.5% of them were expressed in similar quantity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Dried saliva spot sampling is a minimally invasive technique for the spatial mapping of salivary protein distribution in the oral cavity. In conjunction with untargeted nano-flow liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) analysis, DSS is used to compare the proteomes secreted by unstimulated parotid and submandibular/sublingual salivary glands. Two hundred and twenty proteins show a statistically significant association with parotid gland secretion, while 30 proteins are at least tenfold more abundant in the submandibular/sublingual glands. Protein identifications and label-free quantifications are highly reproducible across the paired glands on three consecutive days, enabling to establish the core proteome of glandular secretions categorized into eight salivary protein groups according to their biological functions. The data suggest that the relative contributions of the salivary glands fine-tune the biological activity of human saliva via medium-abundant proteins. A number of biomarker candidates for Sjögren's syndrome are observed among the gland-specifically expressed proteins, which indicates that glandular origin is an important factor to consider in salivary biomarker discovery., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Exposures to dietary tannic acid (TA, 3%) and quinine (0.375%) upregulate partially overlapping sets of salivary proteins which are concurrent with changes in taste-driven behaviors, such as rate of feeding and brief access licking to quinine. In addition, the presence of salivary proteins reduces chorda tympani responding to quinine. Together these data suggest that salivary proteins play a role in bitter taste. We hypothesized that salivary proteins altered orosensory feedback to bitter by decreasing sensitivity to the stimulus. To that end, we used diet exposure to alter salivary proteins, then assessed an animal's ability to detect quinine, using a 2-response operant task. Rats were asked to discriminate descending concentrations of quinine from water in a modified forced-choice paradigm, before and after exposure to diets that alter salivary protein expression in a similar way (0.375% quinine or 3% TA), or 1 of 2 control diets. Control animals received either a bitter diet that does not upregulate salivary proteins (4% sucrose octaacetate), or a nonbitter diet. The rats exposed to salivary protein-inducing diets significantly decreased their performance (had higher detection thresholds) after diet exposure, whereas rats in the control conditions did not alter performance after diet exposure. A fifth group of animals were trained to detect sucrose before and after they were maintained on the 3% TA diet. There was no significant difference in performance, suggesting that these shifts in threshold are stimulus specific rather than task specific. Taken together, these results suggest that salivary proteins reduce sensitivity to quinine., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Rhipicephalus microplus salivary gland secretes a number of complex bioactive proteins during feeding. These components are important in feeding and affect anti-coagulation, anti-inflammation and also have anti-microbial effects. In this study, tick saliva was collected from partially engorged female (PEF) and fully engorged female (FEF) ticks. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) and isobaric tags for relative and absolute quantification (iTRAQ) were used to identify and quantify R. microplus salivary proteins. A total of 322 unique peptides were detected and 151 proteins were characterized in both PEF and FEF. Of these, 41 proteins are considered as high-confidence proteins. Fifteen high-confidence proteins were upregulated and six high-confidence proteins were downregulated (p < 0.05; PEF:FEF ratio ≥ 1.2 or PEF:FEF ratio ≤ 0.83); 17 high-confidence proteins are slightly changed (PEF:FEF ratio > 0.83 and < 1.2). These high-confidence proteins are involved in several physiological roles, including egg development, transportation of proteins, immunity and anti-microorganism, anti-coagulant, and adhesion. In comparison with PEF, the number of upregulated proteins exceeded the number of proteins downregulated. Salivary protein may be induced by the blood-meal and these proteins contribute to successful feeding.

Background: The biochemical components of saliva can change in certain pathologies in horses, for example in acute abdominal disease. The aim of this study was (1) to evaluate if a panel of biochemical analytes usually used in serum can be measured in saliva of horses and (2) to study the possible changes of these biochemical analytes in saliva of horses affected by acute abdominal disease. A panel of 23 analytes was analytically validated in saliva of horses and possible changes in these analytes in a pilot study with six healthy horses and six horses with acute abdominal disease were evaluated. The analytes with significant changes were then evaluated in a larger population of 20 healthy and 37 diseased horses., Results: Seven analytes showed significant increases in the pilot study which were confirmed in the larger population. The analytes which showed significant changes, and their median fold increase and significance shown in the larger population were salivary γ-glutamyl transferase (gGT, 2.3 fold, P = 0.001), creatine kinase (CK, 6.2 fold, P < 0.001), urea (2.3 fold, P = 0.001), total bilirubin (2.6 fold, P < 0.001), total proteins (3.2 fold, P < 0.001), phosphorus (P, 4.5 fold, P < 0.001) and alpha-amylase (sAA, 8.5 fold, P < 0.001). Total proteins, P and sAA showed sensitivities higher than 70% at their optimal cut-off points and a specificity of 100% in differentiating between healthy horses and those with acute abdominal disease., Conclusions: A panel of 23 biochemical analytes can be measured in saliva of horses, where gGT, CK, urea, total bilirubin, total protein, P and sAA levels are raised in horses with acute abdominal disease.

Non-invasive diagnosis of cancer is often the key to effective treatment and patient survival. Saliva as a multi-constituent oral fluid comprises various disease signaling biomarkers, holds great potential for early-stage cancer diagnostics with cost-effective and easy collection, storage, transport and processing. Therefore, detection of biomarkers and proteins in the saliva samples is highly demand. The current review was performed using reliable internet database (mainly PubMed) to provide an overview of the most recent developments on non-invasive diagnosis of cancers in saliva and highlights main challenges and future prospects in sensing of the salivary biomarkers. The conventional detection methods of cancer biomarkers in saliva is discussed in the paper, however, the main focus is on non-invasive diagnosis of cancers in saliva using immunosensing (electrochemical, optical, piezoelectric), DNA based sensors, aptasensors and peptide based bio-assays The reviewed literature revealed that non-invasive cancer detection methods using the mentioned biosensors and without any processing of saliva sample offers a quick, sensitive, specific and cost effective analytical tool. Besides, salivary based detection methods can be used for simultaneous detection of panels of disease specific biomarkers in a real time manner or as home testing kits in near future., (Copyright © 2018. Published by Elsevier B.V.)

Objectives: Opiorphin is a recently discovered peptide shown to inhibit the enkephalin-degrading enzymes and prolong the effects of enkephalins. Although opiorphin is found in high concentrations in saliva, the relationship between salivary opiorphin and orofacial pains is not yet fully understood. We aimed to determine salivary opiorphin concentrations in dental pain related to symptomatic irreversible pulpitis (SIP), and symptomatic apical periodontitis (SAP)., Design: 39 patients participated in this study. The participants were categorized into SIP and SAP based on their diagnosis. All the patients were treated with root canal treatment. Saliva specimens were collected, and pain levels were recorded at pre-treatment, 7 days post-treatment and 30 days post-treatment. Saliva opiorphin levels were measured using a commercially available ELISA kit. Pre-treatment and post-treatment opiorphin levels were evaluated using repeated measures ANOVA. Correlations between VAS scores, opiorphin levels and age were evaluated using Spearman's Rank Correlation., Results: The average saliva opiorphin level pre-treatment, 7 days post-treatment and 30 days post-treatment were 31.28 ± 7.10 ng/ml, 20.41 ± 2.67 ng/ml and 18.61 ± 2.05 ng/ml respectively. Significantly higher pre-treatment opiorphin levels were observed in the SIP group compared to the SAP group. A strong correlation was observed between the pre-treatment pain levels and the saliva opiorphin concentrations., Conclusions: Our findings indicate that saliva opiorphin levels increase in inflammation related dental pain. The level of salivary opiorphin is strongly correlated with the reported level of pain. The extent of the inflammation (pulpal vs. periodontal) also affects the opiorphin level., (Copyright © 2018 Elsevier Ltd. All rights reserved.)