Gender differences in the saliva of young healthy subjects before and after citric acid stimulation

Comparison of epidermal growth factor expression and secretion in human salivary glands

OBJECTIVE

To investigate the expression and secretion of epidermal growth factor (EGF) in major and minor salivary gland tissues of human subjects and to examine the potential influence of sex and age on EGF expression and secretion.

DESIGN

Saliva samples from the oral cavity at rest and after citric acid stimulation, as well as serum samples, were collected from 150 healthy subjects, and the concentrations of EGF were measured with enzyme-linked immunosorbent assay (ELISA) and compared. The expression of EGF mRNA and protein in normal salivary gland tissues was measured by real-time polymerase chain reaction (RT-PCR), Western blot (WB), and immunohistochemistry (IHC).

RESULTS

The EGF concentration in acid-stimulated saliva was significantly higher than that in resting saliva (P < 0.001), and significantly higher than that in serum (P < 0.001). No sex difference was observed in EGF levels of whole saliva and serum, whereas the EGF levels in saliva and serum were decreased with age (P < 0.001 and P < 0.001, respectively). The EGF concentration and compound secretion rate (CSR) in resting submandibular glands saliva were significantly higher than those in resting parotid glands saliva (P = 0.002 and P < 0.001, respectively). The EGF was expressed in all major and minor salivary glands and ranked in order of submandibular, parotid, sublingual, and labial glands.

CONCLUSION

All salivary glands have the function of secreting EGF, and the submandibular gland is the main source of salivary EGF. Aging is a factor influencing the expression and secretion of EGF.

Females have lower salivary flow than males, before and after radiation therapy for head/neck cancer

OBJECTIVE

To compare salivary flow rates between females and males, before and after radiation therapy (RT) for head and neck cancer (HNC).

METHODS

Prospective observational multicenter cohort study (OraRad). Stimulated whole salivary flow was measured before RT and at 6 and 18 months after RT.

RESULTS

Mean (95% confidence interval) salivary flow in g/min before RT was 0.81 (0.71, 0.90) in females (n = 107) and 1.20 (1.15, 1.25) in males (n = 391) (p < 0.001); at 6 months was 0.34 (0.24, 0.44) in females and 0.50 (0.44, 0.55) in males (p = 0.01); at 18 months was 0.49 (0.38, 0.59) in females and 0.70 (0.64, 0.75) in males (p < 0.001). Median nadir salivary flow after RT was 0.22 in females and 0.35 in males (p < 0.001). A lower nadir salivary flow in females, but not males, was associated with an increased risk for tooth failure (p = 0.02).

CONCLUSIONS

Females with HNC have lower stimulated whole salivary flow than males, before and after RT. Low salivary flow after RT may be a risk factor for tooth failure among females. The lower pre-RT salivary flow rates in females, combined with prior literature in other populations, indicates that, in general, females have lower stimulated salivary flow than males.

Partial glass-ceramic posterior restorations with margins beyond or above the cemento-enamel junction: An observational retrospective clinical study

PURPOSE

This observational retrospective clinical study aimed to investigate the survival and success rates of partial indirect lithium disilicate restorations with margins extending above or beyond the cementoenamel junction (CEJ).

METHODS

The study included patients who underwent partial indirect lithium disilicate restorations with immediate dentin sealing (IDS) between January 2008 and October 2018. All the restorations were placed in a single general dental practice following a standardized protocol. The impact of various predictive variables on the survival rates was assessed. Moreover, modified United States Public Health Service (USPHS) criteria were used to evaluate the survival quality.

RESULTS

Totally 1146 partial indirect lithium disilicate restorations in 260 patients were evaluated over an average period of 7.5 years. The cumulative survival and success rates were 97.3% and 95.3%, respectively. Margins extending beyond the cemento-enamel junction did not increase the risk of success or survival failure (P > 0.05). Patients with a high risk of caries, male sex, or non-vital teeth had a significantly higher risk of restoration failure (P < 0.05). Restorations with longer clinical service times exhibited marginally lower clinical quality (P < 0.001).

CONCLUSIONS

Partial indirect glass-ceramic restorations demonstrated survival and success rates of 97.3% and 95.3%, respectively, over an extended period. However, a higher risk of restoration failure existed in patients with a high caries risk for (pre)molars that had undergone endodontic treatment and in males. In terms of the risk of success or survival failure, comparable results were obtained for the positions of the restoration margin in relation to the cemento-enamel junction.

Integrated therapy of intraductal irrigations and sialoendoscopies of salivary glands to improve mouth dryness

OBJECTIVE

To assess the combination of salivary gland intraductal irrigations (IG) followed by sialoendoscopy irrigations (SI) of the parotid gland on the improvement of salivary gland secretory dysfunction (SGSD).

METHODS

We retrospectively analyzed the records of SGSD patients who underwent major salivary gland IG followed by SI during 2014-2020. Records included demographics, systemic background, signs, and symptoms. Improvement was assessed by comparing the mean unstimulated and stimulated whole salivary flow rate (UWSF, SWSF) from the baseline point (before IG procedure) to the last point (after SI) using repeated measures. The between-subjects effects of various factors and covariants were analyzed using repeated measures ANCOVA.

RESULTS

One hundred patients were included with an age range of 15-83 years (mean age of 60.1 ± 13.1 years). Improvement was detected on UWSF measurements (p = 0.031, F = 3.83), but not on SWSF measurements (p = 0.165, F = 1.85). The between-subjects effects on UWSF measurements were statistically significant for sex (p = 0.003, F = 9.526) and salivary gland manipulators use (p < 0.001, F = 15.107) and for the interaction between sex and salivary gland manipulators use (p- = 0.002, F = 9.709). Results of long-term follow-up for 10.87 ± 11.79 months after the SI procedure demonstrated sustained improvement in UWSF measurements (p = 0.011, F = 4.91).

CONCLUSIONS

The combination of IG followed by SI increases UWSF salivary secretion in SGSD patients for a relatively extended duration.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.

Influence of gender and combined estrogen-progestin oral contraceptive on parotid saliva flow rate, pH, and electrolytes concentration

OBJECTIVES

Endocrinal variations within an individual impact the electrolyte composition, pH, and flow-rate (FR) of saliva. The aim of this study was to evaluate the gender-specific differences and the effect of combined estrogen-progestin oral contraceptives (COCs) on FR, pH, and electrolyte concentrations in the parotid saliva (PS) of a group of healthy adults.

MATERIAL AND METHODS

Stimulated PS was collected from 20 healthy adults using a Lashley cup; 11 males, 8 females, and 1 female undertaking combined contraceptive therapy (levonorgestrel/ethinyloestradiol 0.1 mg + 0.02 mg). FR and pH were recorded for each saliva sample. Electrolytes concentrations (Na+ , Ca2+ , K+ , Mg2+ ) were measured using inductively coupled plasma optical emission spectrometer (ICP-OES). Statistical analysis was performed, and the significance level was set at p < .05.

RESULTS

PS FR varied from 0.13 to 0.42 mL/min in females not taking any medication and from 0.08 to 0.5 mL/min in males not taking any medication. PS pH of females and males not taking any medication ranged from 6.23 to 7.50 and from 6.15 to 7.55. PS pH and FR of the female taking COCs were 6.5 and 0.1 mL/min. PS pH, FR, and electrolytes concentrations (Ca2+ , Na+ , K+ , Mg2+ ) were not statistically significantly different between females and males not taking any medication. PS concentrations of Ca2+  and Na+ were significantly higher in the females taking COCs than in the females not taking any medication. Whereas, concentrations of K+ and Mg2+ did not differ significantly between the females taking COCs and the females not taking any medication.

CONCLUSIONS

There are no significant gender-specific differences in PS flow rate, pH, and electrolyte concentrations of Na+ , Ca2+ , Mg2+ , and K+ . Combined hormonal oral contraceptive has a significant effect on PS flow rate, pH, Ca2+ , and Na+ concentrations. Whereas the PS concentration of K+ and Mg2+ are not influenced by COCs. These results warrant further investigation.

Topical review - salivary biomarkers in chronic muscle pain

BACKGROUND AND AIMS

Muscle related temporomandibular disorders (myogenous TMD), one of the most common orofacial pain conditions, is characterized by facial pain and often accompanied by jaw movement limitations. Although the underlying biological mechanisms are still unclear, a cluster of proteins and peptides is assumed to be involved in the pathophysiology. These proteins and peptides may be measured in a simple non-invasive saliva sample. This work investigated whether saliva can be used to sample algogenic substances that can serve as molecular biomarkers for TMD myalgia.

METHODS

Saliva and blood samples were collected from healthy individuals (n=69) and patients diagnosed with TMD myalgia (n=39) according to the Diagnostic Criteria for TMD. Unstimulated and stimulated whole, parotid, and sublingual saliva were analysed. The protein profiles were investigated using two-dimensional gel electrophoresis followed by identification with liquid chromatography tandem mass spectrometry. Levels of nerve growth factor (NGF), calcitonin gene-related peptide (CGRP), and brain derived neuro-tropic factor (BDNF) were determined using western blotting based technology and multiplex electro-chemiluminescence assay panel. Glutamate, serotonin, and substance p (SP) were determined using commercially available methods.

RESULTS

Different saliva collection approaches resulted in significant differences in the protein profile as well as in the expression of NGF, BDNF, CGRP, SP, and glutamate. Stimulated whole saliva showed least variability in protein concentration (35%) and was correlated to plasma levels of glutamate. Unlike SP and glutamate, NGF and BDNF expressed a rhythmic variation in salivary expression with higher levels in the morning (p<0.05). Patients with a diagnosis of TMD myalgia had significantly higher levels of salivary glutamate but lower salivary NGF and BDNF compared to controls; in addition, the lower NGF and BDNF levels correlated to psychological dysfunction. The quantitative proteomics data revealed 20 proteins that were significantly altered in patients compared to controls. The identified proteins are involved in metabolic processes, immune response, and stress response. Dissimilarities in protein profile and clinical variables were observed between TMD myalgia and myofascial pain.

CONCLUSIONS

The work highlights the importance of consistency in saliva collection approaches, including the timing of the collection. It displayed significant changes in pain specific mediators and protein profile in TMD myalgia and furthermore dissimilarities between subclasses indicating different pathophysiology. After extensive validation, potential salivary biomarkers can be combined with clinical features to better understand and diagnose TMD myalgia.

Is oral microbiota associated with overweight and obesity in children and adolescents? A systematic review

This article aims to verify the relationship between the composition and diversity of oral microbiota with overweight and obese children and adolescents. This systematic review was registered in PROSPERO, followed PRISMA 2020, and included an electronic search until March 2022, in PubMed/MEDLINE, Web of Science, Scopus, and The Cochrane Library databases. Studies were eligible if they compared the oral microbiota according to nutrition status among children and adolescents. Independent peers using JBI Critical Appraisal Checklists assessed the quality of studies. Eleven studies were eligible to be included in this review, with a total of 1,695 children and adolescents, 224 were obese, 190 were overweight, 1,154 were eutrophics and 127 were underweight. The most frequent phyla in overweight and obese children and adolescents, in comparison to their counterparts were Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria. It was identified that nine of the eleven articles selected showed an association between oral microbiota and overweight and obesity in children and adolescents. We observed that there is an important association between oral bacterial composition diversity and overweight and obesity. This finding indicates the relevance of the evaluation and surveillance in oral health to control cases of overweight and obesity in children and adolescents.

Assessment of oral and overall health parameters using the SillHa Oral Wellness System

OBJECTIVE

The study evaluated use of a multipoint saliva analyzer to assess patient wellness in a contemporary dental practice setting.

STUDY DESIGN

Unstimulated saliva from a diverse 104 patient cohort was analyzed using the SillHa Oral Wellness System. The device measures the following 7 analytes present in the patient's oral rinse: cariogenic bacteria, acidity, buffer capacity, blood, leukocytes, protein, and ammonia. Data obtained were compared with validated clinical assessment data independently provided by credentialed dental professionals.

RESULTS

Measured leukocyte and protein levels were higher in patients with periodontal disease and/or deep gingival pockets. Patients with a history of cancer and/or diabetes presented with higher ammonia and lower leukocyte levels. Acidity levels were higher in patients using multiple xerogenic medications and lower in patients with a history of sleep apnea. Sex differences showed female patients exhibiting higher acidity, lower buffer capacity, and lower ammonia than male patients. Increasing age is associated with elevated buffer capacity.

CONCLUSIONS

Multipoint saliva analyzers such as the one used in this study, along with clinical practice examination and medical history, can provide rapid salivary component analysis that augments treatment planning. A follow-up multisite study would provide the opportunity to test this analyzer in clinical sites with different practice workflows.

Diurnal pattern of salivary alpha-amylase and cortisol under citric acid stimulation in young adults

Background

Saliva composition has diurnal variations. Citric acid stimulation plays a major role in the change of salivary flow rate and salivary composition. However, diurnal variations and sex differences in salivary alpha-amylase (sAA), pH, salivary flow rate (SFR), and salivary cortisol before and after citric acid stimulation remain unclear.

Methods

We recruited 30 healthy volunteers, including 15 women (24.7 ± 1.0 years old) and 15 men (25.3 ± 1.3 years old). At four time points (T1, 7:00; T2, 10:00; T3, 16:00; and T4, 20:00), saliva was collected from healthy volunteers before and after citric acid stimulation; and sAA, pH, SFR and salivary cortisol were measured and compared between men and women.

Results

There were circadian fluctuations in sAA activity, SFR, pH, and cortisol level both before and after citric acid stimulation, and the diurnal fluctuations of these indexes were not affected by citric acid stimulation. There were significant differences in salivary cortisol between men and women before and after acid stimulation in T1. Neither SFR nor pH showed sex-related differences before or after acid stimulation. The variation trend of sAA activity was contrary to that of cortisol, with a significant negative correlation.

Conclusions

Our data suggest that sAA and cortisol showed diurnal fluctuation, and the variation characteristics of male and female under resting state and acid stimulation were basically the same. The variation trend of salivary alpha-amylase activity was opposite to that of cortisol, with significant negative correlation. Our findings may enable the selection of the correct sampling time for research and the selection of appropriate sampling strategies in studies investigating chronic psychosocial conditions.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Salivary microRNA-126 and 135a: a potentially non-invasive diagnostic biomarkers of type- 2 diabetes

Purpose

Emerging of miRNAs have illustrated the new mechanistic layer to regulate type 2 diabetes process and suggests a possible role of these RNAs in this defect. Thus, we designed this study to improve our understanding of salivary miRNA-126 and 135a expression utility as an easy of collection and non-invasive way in diabetic patients instead of blood sample.

Methods

This case-control study was done on T₂D (n = 40) and healthy individuals (n = 40). The level of biochemical parameters were determined by enzymatic methods as well as glycosylated hemoglobin (HbA1c) was measured by immunoturbidimetry. We used the pooled whole stimulated saliva sample from cases and controls to assess the differentiation expression of miRNA 126 and 135-a with quantitative RT-PCR method. Unpaired Student's t test, Pearson's correlation coefficient and Receiver Operating Characteristic (ROC) analysis were used.

Results

A correlation was observed between the level of HbA1c, glucose and lipid profiles (TG, TC, and LDL) in serum and whole stimulated saliva samples in T₂D patients compared to control (p < 0.001). miR-135a expression was considerably higher by 4.7-fold in T₂D compared to the control group (1.8-fold) (p < 0.001) while the miR126 expression was significantly decreased by 3.9-fold in T₂D compared to the controls (6.3-fold) (p < 0.001).

Conclusions

The results of this case and control study showed that miR-135a and miR126 expression in saliva fluid as a reliable biomarkers and non-invasive approach in combination by change of lipid profiles, glucose and HbA1c may be used to monitor diabetic and non-diabetic patients, while further research is needed to investigate the relationship of these salivary miRNAs (miR135a, miR126) levels change on shifting the levels of clinical laboratory outcomes.

Spectroscopic molecular-fingerprint profiling of saliva

Saliva analysis has been gaining interest as a potential non-invasive source of disease indicative biomarkers due to being a complex biofluid correlating with blood-based constituents on a molecular level. For saliva to cement its usage for analytical applications, it is paramount to gain underpinning molecular knowledge and establish a 'baseline' of the salivary composition in healthy individuals as well as characterize how these factors are impacting its performance as potential analytical biofluid. Here, we have systematically studied the molecular spectral fingerprint of saliva, including the changes associated with gender, age, and time. Via hybrid artificial neural network algorithms and Raman spectroscopy, we have developed a non-destructive molecular profiling approach enabling the assessment of salivary spectral changes yielding the determination of gender and age of the biofluid source. Our classification algorithm successfully identified the gender and age from saliva with high classification accuracy. Discernible spectral molecular 'barcodes' were subsequently constructed for each class and found to primarily stem from amino acid, protein, and lipid changes in saliva. This unique combination of Raman spectroscopy and advanced machine learning techniques lays the platform for a variety of applications in forensics and biosensing.

The neutralizing effect of mouth rinsing with alkaline electrolyzed water on different regions of the oral cavity acidified by acidic beverages

PURPOSE

Acids contained in foods and drinks are involved in the initiation and progression of dental erosion which causes tooth wear. The authors evaluated the neutralizing activity of alkaline electrolyzed water (AEW) in vitro and in vivo.

METHODS

The neutralizing ability of AEW against eight beverages was investigated in vitro. Furthermore, in an in vivo study, the effect of mouth rinsing with AEW on the pH of the oral cavity acidified with acidic beverages was examined. Following mouth rinsing, the oral pH was measured using a pH meter with a micro pH-sensor at the cervical surface of the mandibular teeth and the surface of soft tissues.

RESULTS

Regarding the neutralizing ability, the higher the pH of the AEW, the lower the volume required for neutralization of the tooth surface. Changes in the pH by mouth rinsing with AEW and purified tap water (PTW) were analyzed. The degree of increase of pH with AEW was greater than with PTW at almost all sites.

CONCLUSION

These results suggest that AEW has the potential to prevent the initiation and progression of dental erosion. Mouth rinsing with AEW could be a simple and effective way to prevent the initiation and progression of dental erosion and dental caries.

Saliva pH and Flow Rate in Patients with Periodontal Disease and Associated Cardiovascular Disease

BACKGROUND Periodontal disease, a frequent oral health problem, is connected with cardiovascular morbidity and mortality. This study aimed to assess the unstimulated saliva flow rate and saliva pH as markers of the severity of periodontal disease in patients with cardiovascular disease. MATERIAL AND METHODS A cohort of 155 patients (78 men and 77 women, aged 30-92 years) was included, and a structured questionnaire obtained information about their health status, oral healthcare behaviors, and eating habits. An oral examination was performed to assess periodontal status and presence of dental calculus. The unstimulated whole salivary flow rate and salivary pH were measured. An oral hygienization was performed, and 3 months later, salivary flow rate and pH were reevaluated. RESULTS A severe form of periodontal disease was found in 22.4% of patients. Disease severity was strongly correlated with low pH values (6.25 in stage IV periodontal disease), lower salivary flow rate (0.28 mL/min), smoking, poor oral hygiene habits and obesity, with no significant differences by sex. We observed a significant increase of pH (up to 6.30±0.17) in patients with severe periodontal disease (P=0.001) and salivary flow rate values (0.29±0.07 mL/min; P=0.014) 3 months after oral hygienization. There was a strong association between the severity of periodontal disease and presence of cardiovascular disease (P=0.001). CONCLUSIONS Our study suggests that the decrease of salivary flow rate and pH level might be associated with the severity of periodontal disease.

Artificial oral fluid characterisation: Potential for use as a reference matrix in drug testing

Quality assurance schemes for drug-screening programmes require access to large quantities of biological matrices for reference or control samples. This presents problems when the availability of a matrix, such as oral fluid (OF) for screening or for confirmatory purposes, limits the collection of large volumes. In such cases, synthetic alternatives of OF may provide a solution. The preparation of an artificial (synthetic) oral fluid (AOF) was conducted by dissolving its components (salts, surfactant, antimicrobial agent and mucin) in water. We characterised the physical properties of AOF to determine its suitability as a matrix for quality assurance purposes. The evaluation of pH, specific gravity (SG), conductivity (mS cm^-1 ), freezing point depression (°C), light-scattering and kinematic viscosity (mm² s^-1 ) showed AOF to be a stable, reliable matrix. Synthetic OF was prepared using components (mucin, surfactants and so on) obtained from different suppliers and a comparison was performed. Our results suggest that AOF is a feasible matrix for the preparation of quality assurance samples for confirmatory or drug screening programmes.

Time Course of Salivary Protein Responses to Cranberry-Derived Polyphenol Exposure as a Function of PROP Taster Status

Astringency is a complex oral sensation, commonly experienced when dietary polyphenols interact with salivary proteins. Most astringent stimuli alter protein levels, which then require time to be replenished. Although it is standard practice in astringency research to provide breaks in between stimuli, there is limited consensus over the amount of time needed to restore the oral environment to baseline levels. Here we examined salivary protein levels after exposure to 20 mL of a model stimulus (cranberry polyphenol extract, 0.75 g/L CPE) or unsweetened cranberry juice (CJ), over a 10 min period. Whole saliva from healthy subjects (n = 60) was collected at baseline and after 5 and 10 min following either stimulus. Five families of proteins: basic proline-rich proteins (bPRPs); acidic proline-rich proteins (aPRPs); histatins; statherin; and S-type cystatins, were analyzed in whole saliva via HPLC-low resolution-ESI-IT-MS, using the area of the extracted ion current (XIC) peaks. Amylase was quantified via immunoblotting. In comparison to baseline (resting), both stimuli led to a rise in levels of aPRPs (p < 0.000) at 5 min which remained elevated at 10 min after stimulation. Additionally, an interaction of PROP taster status and time was observed, wherein super-tasters had higher levels of amylase in comparison to non-tasters after stimulation with CJ at both timepoints (p = 0.014–0.000). Further, male super-tasters had higher levels of bPRPs at 5 min after stimulation with both CJ and CPE (p = 0.015–0.007) in comparison to baseline. These data provide novel findings of interindividual differences in the salivary proteome that may influence the development of astringency and that help inform the design of sensory experiments of astringency.

Age and gender characteristics of the biochemical composition of saliva: Correlations with the composition of blood plasma

Background

Recently, the attention of researchers to the study of the properties of human saliva, as a material with unique properties and diagnostic capabilities, has increased.

Research objective

to study the connection of the biochemical composition of saliva and blood plasma in the norm, depending on gender and age.

Methods

107 volunteers took part in the study, including 46 female (37.2 ± 3.9 years old) and 61 male (36.1 ± 2.8 years old). In all samples of saliva and blood plasma, 16 biochemical parameters were determined, including mineral and protein composition, enzyme activity. Non-parametric statistical methods were used to process the data.

Results

It has been shown that it is difficult to establish an unambiguous relation between biochemical parameters of saliva and blood plasma. The calculation of the Spearman correlation coefficients showed that only 7 of the 16 parameters demonstrate the presence of a weak correlation between the content in saliva and plasma.

Conclusion

In general, the determination of the composition of saliva may have an independent diagnostic value; in this case, drawing a parallel with the composition of serum and blood plasma is not advisable. Nevertheless, the use of saliva in clinical laboratory diagnostics is associated with the need to establish criteria for the norm and pathology for each biochemical parameter.

Shifts in the bacterial community of saliva give insights on the relationship between obesity and oral microbiota in adolescents

The current study aimed at the determination of the impact of obesity on the salivary microbiome in adolescents. Sixty subjects ranging 14-17 years old were enrolled (obese: n = 30-50% females, and normal weight: n = 30-50% females). Stimulated saliva was collected for denaturing gradient gel electrophoresis (DGGE) band patterns and massive 16S rRNA gene sequencing using the Ion Torrent platform. Overall, data analysis revealed that male subjects harbored a higher diverse salivary microbiome, defined by a significant higher richness (32.48 versus 26.74) and diversity (3.36 versus 3.20), higher Simpson values (0.96 versus 0.95) and distinct bacterial community structure considering either sex or condition (p < 0.05). Bacterial community fingerprinting analysis in human saliva showed a positive correlation with increased body mass index (BMI) in adolescents. Veillonella, Haemophilus and Prevotella occurrence was found to be affected by BMI, whereas Neisseria and Rothia occurrence was significantly impacted by sex in obese subjects. Our findings suggest that male and female adolescents may harbor a naturally distinct salivary microbiota and that obesity may specifically have an impact on their oral bacterial community. The potential dysbiotic oral microbiome in obese adolescents raises new insights on the etiology and prevention of future conditions in these populations.

Abnormalities in acute salivary biochemical characteristic responses to gustatory stimulation with citric acid in chronic non-atrophic gastritis

BACKGROUND AND AIM

Salivary characteristics are altered in gastrointestinal diseases and related to oral taste disorder. However, specific salivary biochemical characteristics and their relationships with oral taste disturbances in chronic non-atrophy gastritis (CNAG) remain uncertain.

METHODS

Seventy patients with CNAG and 70 subjects in healthy control group (HCG) were enrolled in our study. The levels of salivary flow rate (SFR), pH, salivary α-amylase (sAA) activity, total protein density (TPD), chloride concentration, and calcium concentration were determined before and after citric acid stimulation and compared between CNAG with and without oral taste disturbances.

RESULTS

Average body mass index (BMI) of CNAG (17.75 ± 2.08) was lower than that of HCG (21.96 ± 1.72, P < 0.01). Compared with HCG, CNAG showed increased TPD and calcium concentration but decreased SFR both before and after acid stimulation (P < 0.01), as well as reduced sAA and salivary chloride responses to acid stimulation (P < 0.01). Compared with CNAG with normal BMI (24.29%, 17/70), sAA activity response to acid stimulation was reduced in those with low BMI (75.71%, 53/70, P < 0.05). Under resting condition, CNAG with dry mouth (55.71%, 39/70) showed increased SFR and decreased TPD (P < 0.05), as compared with CNAG without dry mouth (44.29%, 31/70). Compared with CNAG without bitter taste (57.14%, 40/70), pH was decreased in those with bitter taste (42.86%, 30/70) under both resting and stimulated conditions (P < 0.05).

CONCLUSION

Decreased sAA activity may reflect malnutrition state and be one potential marker of poor digestion, decreased salivary pH may contribute to bitter taste perception, and reduced TPD might be a cause of dry mouth in CNAG.

Erosion-Protective Capacity of the Salivary Pellicle of Female and Male Subjects Is Not Different

This study aimed to analyse if the erosion-protective potential of the salivary pellicle is different between female and male subjects. Bovine enamel and dentin specimens (each n = 3) were exposed to the oral cavity of healthy female or male volunteers (each n = 25, females: 25.8 ± 3.5 years, males: 26.7 ± 4.0 years) for 120 min to form a salivary pellicle. Subsequently, each 2 enamel and 2 dentin specimens were eroded with hydrochloric acid (pH 2.6, 60 s). Specimens of the control group (each n = 30) were eroded without presenting a salivary pellicle. Calcium release into the acid was determined photometrically. Additionally, total protein content in the pellicle (each n = 1 enamel and dentin specimen/volunteer) and different salivary parameters (flow rate, pH, buffer capacity, protein, albumin, calcium, phosphate, fluoride) were assessed. Statistical analyses were performed by one-way ANOVA, t tests, multiple linear regressions and Pearson correlations (p < 0.05). The erosion-protective capacity was not significantly different among female (calcium release [% of control]: enamel: 82.6 ± 28.1, dentin: 80.7 ± 24.0) and male (enamel: 76.0 ± 27.5, dentin: 87.1 ± 34.9) subjects. The protein content of the pellicle was not different between female and male subjects. The protein content and pH of unstimulated saliva were significantly reduced in female compared to male volunteers. Calcium release was neither correlated with the protein content of the salivary pellicle nor with salivary parameters. Under the conditions of the present study, the erosion-protective capacity of the salivary pellicle of female and male subjects is not different.

Assessment of the Acute Effects of Carbonated Beverage Consumption on Symptoms and Objective Markers of Gastric Reflux

Previous studies have suggested that carbonated beverages may cause gastro-oesophageal reflux. Pepsin (the major enzyme secreted by the stomach) has been suggested to be an objective, acute marker of a reflux event. This pilot study aimed to investigate whether intake of carbonated beverages could affect pepsin concentration in saliva or reflux symptoms. This was assessed by a randomised, crossover trial where participants consumed 330 mL of beverage (carbonated cola, degassed cola or water) at separate visits. Saliva samples and symptom questionnaires were collected at baseline and over the 30 min postprandial period. Pepsin was detected in all saliva samples. No difference was found in the salivary pepsin concentrations between treatments at all time points. There were significantly higher scores (p > 0.05) for feelings of fullness, heartburn, urge to belch and frequency of belches after ingestion of carbonated cola than degassed cola and water. The ingestion of carbonated beverages did not appear to increase postprandial pepsin concentration in saliva compared to other beverages but did evoke higher levels of reflux-related symptoms such as fullness, heartburn and belching. This suggests carbonated beverages may cause symptoms associated with reflux but do not drive detectable levels of gastric juice to reach the oral cavity.

Chronophysiological features of the normal mineral composition of human saliva

BACKGROUND

The high rate of changes in the composition of saliva can be used for the monitoring of various biorhythms in order to study the physiological characteristics of the human body.

RESEARCH OBJECTIVE

The study of the dynamics of the near-24-h mineral composition of saliva in men and women.

METHODS

The study involved 20 men and 20 women, age 23.1±0.9years. Saliva samples were collected every 3h during the day within 10min. The mineral composition of saliva was defined by the capillary electrophoresis technique. The cross-group differences were evaluated using the non-parametric criterion.

RESULTS

It was shown that the maximum values of the mineralizing capacity fall to 7-8 a.m. and 18-19p.m., which is due to the change in the rate of saliva secretion. The near-24-h dynamics of the saliva pH practically coincides with the dynamics of the Ca/P ratio; there are evident maxima at 9:00 am and 15-18p.m. The values of the Na/K ratio are out of phase with the Ca/P ratio. There is one maximum, corresponding to 3 am in the night, and one minimum at 12-13p.m., which is due to a decreased level of sodium and increased potassium concentration. Statistically valid differences between men and women in pH (p<0.001), concentrations of inorganic phosphorus (p<0.001), as well as Ca/P coefficient (p=0.011) were identified.

CONCLUSION

The dynamics of the studied parameters during 24h is characterized by pronounced intervals.