Chewing stimulates secretion of human salivary secretory immunoglobulin A

Influence of female sex hormones on proactive behavioral and physiological immune parameters

Women may be more susceptible to infections in the luteal phase, supposedly as a consequence of the hormone progesterone and its immunosuppressive action. While immunosuppression may be important for successful oocyte implantation and pregnancy, it makes women more vulnerable to pathogens. According to theory, to compensate for reduced immunocompetence, women in the luteal phase exhibit proactive behavioral responses, such as disgust and avoidance of disease-associated stimuli, to minimize contagion risk. However, previous studies yielded inconsistent results, and did not account for accompanying proactive immune responses, like the increase of secretory immunoglobin A (sIgA). Here, we assessed the proactive immune response and feelings of disgust associated with disease cues in the comparison of 61 woman with a natural menstrual cycle (31 in the follicular and 30 in the luteal phase) and 20 women taking hormonal contraception (HC). Women rated disease vulnerability and disgust propensity, watched a video displaying people with respiratory symptoms, which was evaluated for its disgust-evoking potential and contagiousness, and provided saliva samples for hormone and sIgA analysis. Women with HC reported a heightened vulnerability to disease compared to naturally cycling women, whereas both the feeling of disgust and the sIgA increase elicited by the disease video were similar across groups, regardless of progesterone. We found a u-shaped relationship between progesterone and baseline sIgA in naturally cycling women, with its nadir during ovulation. Overall, our data do not support a compensatory relationship between the proposed progesterone-induced immunosuppression and heightened disgust or a proactive sIgA response.

Influence of Chewing Gummy Jelly Containing Aroma Compound on Psychological Stress and Autonomic Nervous System Activity: A Randomized Crossover Trial

The aim of this randomized crossover trial was to clarify the effects of chewing gummy jelly containing a compound of decanoic acid, oligonol, methyl cellulose, and citral (DOMAC) on mental stress and autonomic nervous activity in facemask wearers. A placebo gummy jelly was used in conjunction with DOMAC. Eight healthy adults with no tooth loss (mean age: 35±5 yr) were included. The participants were required to chew one DOMAC or placebo gummy jelly for 5 min after wearing a facemask for 20 min in the laboratory, then the other gummy jelly after a washout period. Rate of change in salivary immunoglobulin A (IgA) as a marker of stress was compared between before and after chewing. Additionally, sympathetic and parasympathetic activity was compared at both time points. A significant difference was observed in the percentage change in salivary IgA from that at before wearing a facemask: 127±34% (mean±standard deviation) while wearing a facemask; 46±20% while chewing DOMAC gummies; and 47±26% while chewing placebo gummies (p<0.05). Parasympathetic nervous system activity was 971.2±1040.7 ms2 at 20 min after facemask wearing; 295.0±253.0 ms2 after DOMAC gummy chewing; and 1956.1±2798.0 ms2 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing (p<0.05). Sympathetic nervous system activity was 1.80±1.83 at 20 min after facemask wearing; 4.06±3.33 after DOMAC gummy chewing; and 4.95±7.02 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing. These results suggest that chewing gummy jellies containing DOMAC relieves stress caused by facemask wearing and activates sympathetic nervous system activity.

SARS-CoV-2 specific sIgA in saliva increases after disease-related video stimulation

Secretory immunoglobulin A (sIgA) in saliva is the most important immunoglobulin fighting pathogens in the respiratory tract and may thus play a role in preventing SARS-CoV-2 infections. To gain a better understanding of the plasticity in the mucosal antibody, we investigated the proactive change in secretion of salivary SARS-CoV-2-specific sIgA in 45 vaccinated and/or previously infected, generally healthy persons (18 to 35 years, 22 women). Participants were exposed to a disease video displaying humans with several respiratory symptoms typical for COVID-19 in realistic situations of increased contagion risk. The disease video triggered an increase in spike-specific sIgA, which was absent after a similar control video with healthy people. The increase further correlated inversely with revulsion and aversive feelings while watching sick people. In contrast, the receptor binding domain-specific sIgA did not increase after the disease video. This may indicate differential roles of the two salivary antibodies in response to predictors of airborne contagion. The observed plasticity of spike-specific salivary antibody release after visual simulation of enhanced contagion risk suggests a role in immune exclusion.

The Role of Genistein in Mammalian Reproduction

Genistein is a natural compound belonging to flavonoids, having antioxidant, anti-inflammatory, and anti-neoplastic properties. Genistein is considered a phytoestrogen. As such, genistein can bind estrogen receptors (ERα and ERβ), although with a lower affinity than that of estradiol. Despite considerable work, the effects of genistein are not well established yet. This review aims to clarify the role of genistein on female and male reproductive functions in mammals. In females, at a high dose, genistein diminishes the ovarian activity regulating several pathway molecules, such as topoisomerase isoform I and II, protein tyrosine kinases (v-src, Mek-4, ABL, PKC, Syk, EGFR, FGFR), ABC, CFTR, Glut1, Glut4, 5α-reductase, PPAR-γ, mitogen-activated protein kinase A, protein histidine kinase, and recently circulating RNA-miRNA. The effect of genistein on pregnancy is still controversial. In males, genistein exerts an estrogenic effect by inducing testosterone biosynthesis. The interaction of genistein with both natural and synthetic endocrine disruptors has a negative effect on testis function. The positive effect of genistein on sperm quality is still in debate. In conclusion, genistein has a potentially beneficial effect on the mechanisms regulating the reproduction of females and males. However, this is dependent on the dose, the species, the route, and the time of administration.

Saliva biomarkers in oral disease

Saliva is a versatile biofluid that contains a wide variety of biomarkers reflecting both physiologic and pathophysiologic states. Saliva collection is noninvasive and highly applicable for tests requiring serial sampling. Furthermore, advances in test accuracy, sensitivity and precision for saliva has improved diagnostic performance as well as the identification of novel markers especially in oral disease processes. These include dental caries, periodontitis, oral squamous cell carcinoma (OSCC) and Sjögren's syndrome (SS). Numerous growth factors, enzymes, interleukins and cytokines have been identified and are the subject of much research investigation. This review highlights current procedures for successful determination of saliva biomarkers including preanalytical factors associated with sampling, storage and pretreatment as well as subsequent analysis. Moreover, it provides an overview of the diagnostic applications of these salivary biomarkers in common oral diseases.

Disease-related disgust promotes antibody release in human saliva

The behavioral immune system (BIS) comprises manifold mechanisms, that may assist the physiological immune system (PIS) in counteracting infection and can even reduce the risk of contagion. Previous studies have found initial evidence for possible interactions between the two systems. However, most of these findings were correlative and have not been replicated. Further, none of these studies examined whether disease stimuli that indicate an enhanced airborne transmission risk may trigger a different immune response in comparison to stimuli that predominantly evoke core disgust. In the present study, we employed a video-priming approach to get further insight in the influence of the perception of disgust- and disease-related stimuli on the rapid physiological immune response, as indicated by changes of secretory immunoglobulin A (S-IgA) in saliva. We created three video primers that represented different categories of disgust- and/or disease-associated content. Two of the videos showed disease-related situations that were associated with contagious respiratory virus infections, varying in concealment of aerosols. The third video incurred no heightened airborne contagion risk, but comprised situations that are known to elicit core disgust, such as rotten foods, decaying animal carcasses, or cockroaches. A fourth video acted as control showing landscape impressions. The different video primers varied in their contagion risk and disgust-evoking potential. Given the role of S-IgA in the mucosal immune defense, we expected differences in the S-IgA response between the two videos indicating a heightened airborne contagion risk and the core disgust video, with the highest S-IgA to occur after the aerosol video. For this, we used the data of 107 healthy participants in a between-subjects design with the four video primers. We found a significant increase of S-IgA in response to both the disease- and the disgust-related videos, which correlated positively with the perceived contagion risk of the displayed situations. Nevertheless, there was no significant difference in the increase between the three disease- and disgust-related videos. We also found that people with a high contamination disgust produced less S-IgA in such situations, which is a hint for a compensating relationship between the BIS and PIS. Our observations suggest that the mere visual perception of videos showing realistic situations of an increased contagion risk can elicit a heightened release of salivary antibodies.

•

Realistic videos of respiratory diseases are efficient to trigger immune responses.

•

Secretory Immunoglobulin A (S-IgA) in saliva increases after video-priming.

•

S-IgA increase is positively correlated with perceived contagion risk.

•

S-IgA increase is inversely correlated with the trait contamination disgust.

Impact of Masticatory Behaviors Measured With Wearable Device on Metabolic Syndrome: Cross-sectional Study

Background

It has been widely recognized that mastication behaviors are related to the health of the whole body and to lifestyle-related diseases. However, many studies were based on subjective questionnaires or were limited to small-scale research in the laboratory due to the lack of a device for measuring mastication behaviors during the daily meal objectively. Recently, a small wearable masticatory counter device, called bitescan (Sharp Co), for measuring masticatory behavior was developed. This wearable device is designed to assess objective masticatory behavior by being worn on the ear in daily life.

Objective

This study aimed to investigate the relation between mastication behaviors in the laboratory and in daily meals and to clarify the difference in mastication behaviors between those with metabolic syndrome (MetS) and those without (non-MetS) measured using a wearable device.

Methods

A total of 99 healthy volunteers (50 men and 49 women, mean age 36.4 [SD 11.7] years) participated in this study. The mastication behaviors (ie, number of chews and bites, number of chews per bite, and chewing rate) were measured using a wearable ear-hung device. Mastication behaviors while eating a rice ball (100 g) in the laboratory and during usual meals for an entire day were monitored, and the daily energy intake was calculated. Participants’ abdominal circumference, fasting glucose concentration, blood pressure, and serum lipids were also measured. Mastication behaviors in the laboratory and during meals for 1 entire day were compared. The participants were divided into 2 groups using the Japanese criteria for MetS (positive/negative for MetS or each MetS component), and mastication behaviors were compared.

Results

Mastication behaviors in the laboratory and during daily meals were significantly correlated (number of chews r=0.36; P<.001; number of bites r=0.49; P<.001; number of chews per bite r=0.33; P=.001; and chewing rate r=0.51; P<.001). Although a positive correlation was observed between the number of chews during the 1-day meals and energy intake (r=0.26, P=.009), the number of chews per calorie ingested was negatively correlated with energy intake (r=–0.32, P=.002). Of the 99 participants, 8 fit the criteria for MetS and 14 for pre-MetS. The number of chews and bites for a rice ball in the pre-MetS(+) group was significantly lower than the pre-MetS(–) group (P=.02 and P=.04, respectively). Additionally, scores for the positive abdominal circumference and hypertension subgroups were also less than the counterpart groups (P=.004 and P=.01 for chews, P=.006 and P=.02 for bites, respectively). The number of chews and bites for an entire day in the hypertension subgroup were significantly lower than in the other groups (P=.02 and P=.006). Furthermore, the positive abdominal circumference and hypertension subgroups showed lower numbers of chews per calorie ingested for 1-day meals (P=.03 and P=.02, respectively).

Conclusions

These results suggest a relationship between masticatory behaviors in the laboratory and those during daily meals and that masticatory behaviors are associated with MetS and MetS components.

Trial Registration

University Hospital Medical Information Network Clinical Trials Registry R000034453; https://tinyurl.com/mwzrhrua

The Origins of Salivary Vitamin A, Vitamin B12 and Vitamin D-Binding Proteins

Vitamin A- (retinol), vitamin B₁₂- (haptocorrin) and vitamin D-binding proteins are the major circulatory transporters of their respective ligands; they are also constituents of the salivary proteome, the origins of which, remain unclear. The aim of this study was to explore how these proteins enter saliva and their relationship (if any) with vitamin status. Firstly, the three vitamin-binding proteins were quantified in resting whole mouth saliva and chewing-stimulated saliva from healthy donors (n = 10) to determine if they enter the mouth by salivary secretion or from the circulation. Secondly paired whole mouth saliva and serum samples were analysed from healthy donors (n = 14) to determine the relationships between the vitamin-binding proteins and vitamin status. Salivary output of all three vitamin-binding proteins studied increased when secretion was stimulated, suggesting they are secreted by the salivary glands. Whilst retinol-binding protein and haptocorrin were secreted by all major salivary glands, vitamin D-binding protein was restricted to the mucus glands. Salivary vitamin-binding protein concentrations were not found to be indicative of systemic vitamin status.

Changes in Salivary Proteome in Response to Bread Odour

It is widely recognized that smelling food results in a mouth-watering feeling and influences appetite. However, besides changes in volume, little is known about the effects that food odours have on the composition of saliva. The aim of the present study was to access the effects that smelling bread has on saliva proteome and to compare such effects with those of chewing and ingesting it. Besides a significant increase in saliva flow rate, together with a decrease in total protein concentration, bread odour induced changes in the proportion of different salivary proteins. The expression levels of two spots of cystatins and two spots of amylase increased due to olfactory stimulation, similar to what happened with bread mastication, suggesting that odour can allow anticipation of the type of food eaten and consequently the physiological oral changes necessary to that ingestion. An interesting finding was that bread odour increased the expression levels of several protein spots of immunoglobulin chains, which were decreased by both bread or rice mastication. This may be of clinical relevance since food olfactory stimulation of salivary immunoglobulins can be used to potentiate the oral immune function of saliva. Moreover, the effects of bread odour in the levels of salivary proteins, previously observed to be involved in oral food processing led to the hypothesis of an influence of this odour in the sensory perception of foods further ingested. Further studies are needed to elucidate this point, as well as whether the changes observed for bread odour are specific, or if different food odours lead to similar salivary proteome responses.

Dietary Flavonoids for Immunoregulation and Cancer: Food Design for Targeting Disease

Flavonoids, one of the most abundant phytochemicals in a diet rich in fruits and vegetables, have been recognized as possessing anti-proliferative, antioxidant, anti-inflammatory, and estrogenic activities. Numerous cellular and animal-based studies show that flavonoids can function as antioxidants by preventing DNA damage and scavenging reactive oxygen radicals, inhibiting formation of DNA adducts, enhancing DNA repair, interfering with chemical damage by induction of Phase II enzymes, and modifying signaling pathways. Recent evidence also shows their ability to regulate the immune system. However, findings from clinical trials have been mixed with no clear consensus on dose, frequency, or type of flavonoids best suited to elicit many of the beneficial effects. Delivery of these bioactive compounds to their biological targets through "targeted designed" food processing strategies is critical to reach effective concentration in vivo. Thus, the identification of novel approaches that optimize flavonoid bioavailability is essential for their successful clinical application. In this review, we discuss the relevance of increasing flavonoid bioavailability, by agricultural engineering and "targeted food design" in the context of the immune system and cancer.

Salivary Biomarkers in Psychoneuroimmunology

As molecular biology advances, an increasing number of proteins are becoming detectable at very low levels in different biological tissues. In this regard, saliva holds vast promise. Unlike blood, saliva can be sampled 1) non-invasively; 2) across all ages (newborn to elderly); 3) in the field; 4) by study participants; and 5) many times per day. With respect to psychoneuroimmunology (PNI), physiological measures of stress such as cortisol have been well characterized. Alpha amylase provides another physiological index of stress; it is a measure of autonomic nervous system activation and is quantifiable in saliva. Other salivary measures, such as inflammatory biomarkers and immunoglobulin A (IgA), provide valuable information pertaining to the effects of stress on inflammation, mucosal immunity, and oral health. Importantly, due to various methodological issues and a lack of strong correlation between saliva and blood measures, investigators should proceed with caution in drawing conclusions from measures of salivary inflammation that pertain to systemic immunity or generalized health.

Exercise, Immunity, and Illness

It is generally accepted that moderate amounts of exercise improve immune system functions and hence reduce the risk of infection whereas athletes engaged in regular prolonged and/or intensive training have a higher than “normal” incidence of minor infections, especially of the upper respiratory tract (URT, e.g., common cold and influenza). This is likely related to regular acute (and possibly chronic) periods of exercise-induced changes in immune function. URT infections can compromise performance directly if suffered shortly before or during competition or indirectly if suffered at other times via effects on training and/or physiological adaptations. This chapter covers the effects of exercise (acute and chronic), both positive and negative, on immune function and consequent infection risk, and considers the current state-of-the-art for monitoring and assessing this in athletes.

Influence of chewing on expression level of human beta-defensin 2 and secretory immunoglobulin A in the epithelium

PURPOSE

This study aimed to clarify the influence of chewing on human β-defensin 2 (hBD-2) and secretory immunoglobulin A (SIgA) expression levels.

METHODS

We included 15 healthy males with no missing teeth (mean age, 25.5±2.5years). Subjects were instructed to chew a piece of gum for 30min. Saliva and skin-extraction samples were collected before and after chewing for 15 and 30min. hBD-2 and SIgA concentrations in the samples were determined using enzyme-linked immunosorbent assay (ELISA). hBD-2 and SIgA expression levels before and after chewing were analyzed using the Mann-Whitney U test, following the Friedman test. The significance level was 0.05.

RESULTS

The hBD-2 level in skin-extraction samples was significantly different before (99.4±17.3pg/mL) and after chewing for 30min (142±23.0pg/mL). The SIgA level in skin-extraction samples was also significantly different before (2.39±0.25μg/mL) and after chewing for 30min (3.61±0.33μg/mL). No significant difference was noted in either hBD-2 or SIgA secretion rate in saliva between before and after chewing.

CONCLUSIONS

Chewing gum for 30min increased hBD-2 and SIgA expression levels in skin. Moreover, chewing gum could influence the secretion pattern of these two biomolecules on skin, but not in saliva.

Elevated salivary alpha-amylase levels at awakening in patients with depression

BACKGROUND

Specific Major Depressive Disorder (MDD) biomarkers could help improve our understanding of MDD pathophysiology and aid in the refinement of current MDD criteria. While salivary cortisol (SC) can differentiate between healthy controls and patients with psychiatric disorders, salivary alpha amylase (sAA), may be a putative candidate biomarker for MDD specifically.

METHODS

In a naturalistic cohort of consecutive out-patients and healthy controls, sAA and SC were determined in 833 participants (97 MDD patients, 142 patients with other mood, anxiety, and/or somatoform (MAS-) disorders, and 594 healthy controls). Samples were collected at 7 different time points (at awakening, after 30, 45, and 60 min, at 10:00 p.m., at 11:00 p.m., and at awakening on day 2).

RESULTS

The mean age of the sample was 43.8 years (SD = 12.9; 63.9% female). Concerning sAA, MDD patients had higher sAA levels upon awakening on two consecutive days (p = 0.04, p = 0.01 respectively), as well as a higher area under the curve with respect to the increase (AUCi; p = 0.04) in comparison to both controls and the other MAS-disorders group. Regarding SC, mean levels of evening SC were elevated in MDD patients (p = 0.049) in comparison to both controls and the other MAS-disorders group. SC values on day 2 after ingestion of dexamethasone were elevated in both MDD patients and the other MAS-disorders group (p = 0.04, p = 0.047 respectively).

CONCLUSIONS

sAA at awakening and not cortisol differentiates MDD from other psychiatric disorders in outpatients. This suggests that sAA may be a valuable candidate biomarker specifically for MDD.

Comparative evaluation of serum and salivary immunoglobulin G and A levels with total serum protein in oral submucous fibrosis patients: A case control study

AIM AND OBJECTIVE

The objective of this study is to estimate and compare the serum and salivary immunoglobulin G and A (IgG, IgA) levels in various stages of oral submucous fibrosis (OSMF) patients and relate it to total serum protein (TSP) and hemoglobin (Hb) levels.

MATERIALS AND METHODS

The sample for the present study comprised a total of 20 healthy controls, 20 OSMF patients. About 5 ml of blood and 2 ml of saliva were collected. Quantitative analysis of serum and salivary IgG, IgA was done by turbidometric immunoassay. TSP and Hb were estimated by Biuret and cyanmethemoglobin methods, respectively.

RESULTS

Serum and salivary IgA and IgG levels were statistically significantly increased (P < 0.001) in OSMF patients when compared to controls. Also serum and salivary IgG and IgA levels showed significantly increased (P < 0.01) in all the three staging of OSMF when compared to control group. Hb levels and TSP levels were significantly decreased (P < 0.001) in OSMF patients when compared to controls. One-way ANOVA, Pearson's correlation, and unpaired t-test were used for statistical analysis.

CONCLUSION

The elevated levels of IgG and IgA are also in favor of polygammapathy, which are nonspecific and nondiagnostic objective reflections of an underlying disease. Decreased TSP is a result of host response and Hb, acts as an indicator of nutritional status plays an important role. It is also observed from the present study that the severity of OSMF was directly proportional to the estimated elevated levels of the major IgG and IgA. A need is also felt for the knowledge of immunoprofile estimation in etiology and pathogenesis that would prove a great asset in the proper assessment of this condition.

Measurement of saliva flow rate in healthy young humans: influence of collection time and mouthrinse water temperature

The aim of the current study was to determine if unstimulated saliva flow (measured in μl min^-1 ) is affected by different durations of sample collection and by temperatures of mouthrinse water used before sample collection. In randomized order, participants provided 10 samples of unstimulated saliva at time points ranging from 1 to 6 min after rinsing with different temperatures of water (10, 20, and 30°C). Data were analysed by one-way anova with post-hoc tests. Test-retest reliability was assessed using Bland-Altman plots and correlation coefficients. A larger volume of saliva was obtained over a longer collection time. No significant difference in saliva flow rate was observed between collection times [mean: 364 (95% CI: 332-397) μl min^-1 ]. Although rinsing with different temperatures of mouthrinse water resulted in no significant difference in saliva flow rates as a result of the mouthrinse water temperatures, 60% of the participants had a higher saliva flow rate after rinsing with mouthrinse water at a temperature of 10°C compared with mouthrinse water at 20 and 30°C, suggesting large individual variation (range: 24-420 μl min^-1 ). These findings provide justification for using saliva collection times of 1-6 min during sampling of unstimulated saliva. The large individual variations in saliva flow rate in response to different mouthrinse water temperatures suggest that standardization, control, and reporting of mouthrinse water temperature is warranted.

Salivary alpha-amylase, secretory IgA and free cortisol as neurobiological components of the stress response in the acute phase of anorexia nervosa

Objectives One novel hypothesis of the pathogenesis of anorexia nervosa (AN) is the possible role of mental stress in hyperactivity of the autonomic nervous system (ANS) and of the hypothalamic-pituitary-adrenal (HPA) axis. Two components of stress response - salivary alpha-amylase (sAA) and free cortisol - have been proposed. They can be determined in saliva, which closely reflects their concentrations in plasma. The purpose of this study was to measure salivary free cortisol, sAA and their correlation to secretory IgA (sIgA) of patients with AN in comparison to the average population. Methods A controlled clinical trial was designed for a matched group of 47 AN patients and 54 healthy individuals. After clinical examination, unstimulated salivary samples were taken during the acute stage of AN (BMI < 15 kg/m(2)) in the first week of hospitalisation. An enzyme-linked immunosorbent assay (ELISA) suitable for measuring sAA, sIgA and free cortisol were used. Results Anorexic patients exhibited disturbances in sAA secretion, and significantly increased cortisol and sIgA levels with a distinct correlation between these two parameters. Conclusions The behaviour of cortisol, sAA and sIgA levels can be assessed as an effect of stress reaction among AN patients with hyperactivity of the HPA axis and ANS dysregulation. The effect of stress response can be assessed reliably in saliva.

Estimation of serum, salivary immunoglobulin G, immunoglobulin A levels and total protein, hemoglobin in smokeless tobacco chewers and oral submucous fibrosis patients

BACKGROUND

Oral submucous fibrosis (OSMF) is a debilitating, potentially cancerous oral condition. Although areca nut is the most important causative agent, it is also considered that the disease is immunologically mediated.

AIM OF THE STUDY

To establish that autoimmunity and nutritional deficiency play a role in the etiopathogenesis of OSMF.

OBJECTIVES OF THE STUDY

To show that serum immunoglobulin markers (immunoglobulin-G [IgG], immunoglobulin-A [IgA]) and nutritional parameters such as total serum protein (TSP), Hemoglobin (Hb) play a role in causing OSMF and also to correlate serum, salivary IgG, IgA levels in OSMF patients.

SETTINGS AND DESIGN

A case-control study was done with 50 patients (25 patients who were provisionally diagnosed as OSMF - Group I, and 25 patients who were chronic smokeless tobacco chewers and who did not have any intraoral lesion - Group II).

MATERIALS AND METHODS

Five milliliters of blood and saliva were collected from both the groups. Quantitative analysis of serum, and salivary IgG, IgA was done by turbidometric immunoassay. TSP and Hemoglobin (Hb) were estimated by spectrophotometry.

STATISTICAL ANALYSIS

Results were analyzed by independent samples t-test and one-way analysis of variance (ANOVA).

RESULTS

All patients of OSMF showed significant (P < 0.01) increase in serum IgG, IgA, and salivary IgG levels as compared to smokeless tobacco chewers. The salivary IgA levels showed a significant decrease in OSMF patients (P < 0.05). TSP and Hb levels showed significant (P < 0.01) decrease in OSMF patients as compared to smokeless tobacco chewers.

CONCLUSION

The elevation of immunoglobulin levels supports the concept of autoimmunity. The decrease in TSP and Hb suggests that nutritional deficiency plays a defined role in the occurrence as well as a further progression of OSMF.

Stimulating whole saliva affects the response of antimicrobial proteins to exercise

This study investigated the salivary secretion rates of antimicrobial proteins in response to prolonged, exhaustive exercise in both stimulated (STIM) and unstimulated (UNSTIM) saliva flow sample methods. Twenty-four trained men cycled for 2.5 h at 60% V̇O₂max and then to exhaustion at 75% V̇O₂max. Timed collections of whole saliva were made before exercise, mid-exercise, at the end of the moderate exercise bout and post-exhaustive exercise. After each UNSTIM collection, a STIM sample was collected following chewing flavored gum for 1 min. Saliva was analysed for lysozyme, α-amylase and salivary immunoglobulin A (s-IgA), and secretion rates were calculated. Saliva flow was 156% higher in STIM compared with UNSTIM (P < 0.001) and decreased with exercise in STIM only (P < 0.001). Exercise increased lysozyme and α-amylase levels and secretion rates were 144% higher and 152% higher in STIM compared with UNSTIM for lysozyme and α-amylase, respectively (all P < 0.001). S-IgA concentration (P < 0.05) and secretion rate (P < 0.001) increased with exercise but were both lower in STIM compared with UNSTIM (P < 0.001). In conclusion, a STIM saliva flow collection during exercise by chewing flavored gum increased the quantity of saliva and the secretion of lysozyme and α-amylase, but had a limited impact on the secretion of s-IgA.

α-Amylase as a reliable and convenient measure of sympathetic activity: don't start salivating just yet!

Recent years have seen a growing interest in salivary α-amylase (sAA) as a non-invasive marker for sympathetic nervous system (SNS) activity. Saliva offers many advantages as a biomarker fluid and sAA is one of its most plentiful components. sAA is a digestive enzyme that breaks down starch, which provides a simple means of quantification by measuring its enzymatic activity. This commentary will address a number of common misconceptions and methodological issues that surround the use of sAA as a marker of SNS activity and limit its utility in biobehavioral research. The usefulness of sAA as an SNS marker is undermined by the fact that the parasympathetic nerves also play a significant role in sAA release. Local parasympathetic nerves regulate sAA activity via: (1) α-amylase release from glands that are solely or mainly parasympathetically innervated; (2) via synergistic sympathetic-parasympathetic effects on protein secretion (known as 'augmented secretion'); and (3) via effects on salivary flow rate. Regarding methodology, we discuss why it is problematic: (1) to ignore the contribution of salivary flow rate; (2) to use absorbent materials for saliva collection, and; (3) to stimulate saliva secretion by chewing. While these methodological problems can be addressed by using standardized and timed collection of unstimulated saliva, the physiological regulation of sAA secretion presents less resolvable issues. We conclude that at present there is insufficient support for the use and interpretation of sAA activity as a valid and reliable measure of SNS activity.

A prospective randomized trial to reduce oral Candida spp. colonization in patients with hyposalivation

Low salivary flow rates are associated with higher oral Candida spp. counts, which may predispose to oral candidiasis. The aim of this study was to compare the effect of stimulating salivary flow rates with that of a regimen of chlorhexidine mouth rinse on the intensity of Candida colonization in patients with reduced salivary flow rates. Thirty-one outpatients were randomized to stimulate salivary output (group 1) or to receive chlorhexidine mouth rinses (group 2). Evaluations were performed at baseline (T0), at end of treatment (T1), and 15 days after last day of treatment (T2). Chewing-stimulated whole saliva samples were collected at each visit. Group 1 showed a constant reduction in median cfu counts, although the difference was significant only between T0 and T2 (p = 0.004). Group 2 showed a reduction in median Candida cfu counts between T0 and T1 (p = 0.01), but the counts increased at T2 (p = 0.01), and the difference between T0 and T2 was not significant (p = 0.8). In conclusion, patients who received salivary stimulation showed reductions of Candida cfu counts in saliva and a trend for increasing salivary flow rates between baseline and end of study evaluations. The use of chlorhexidine mouth rinses dramatically reduced Candida cfu counts, but when patients discontinued treatment, intensity of colonization rose again.

Multicenter randomized trial of chewing gum for preventing oral mucositis in children receiving chemotherapy

The properties of saliva led us to hypothesize that the salivary flow increase induced by gum chewing might protect the oral mucosa from lesions due to cancer chemotherapy. We conducted a multicenter randomized trial to evaluate the efficacy of chewing gum in preventing oral mucositis in 145 children receiving chemotherapy regimens expected to induce WHO grade 3-4 oral mucositis in at least 30% of patients. Patients were allocated at random to standard oral care with or without 5 gum pieces per day. No overall reduction in severe oral mucositis occurred in the gum arm (51%) compared with the standard arm (44%). VIDE, COPADM, and multidrug intensive chemotherapy caused severe oral mucositis in 75% of patients in both arms. In patients receiving less toxic regimens, a decrease in WHO grade 1-4 oral mucositis was noted in the gum arm compared with the standard arm (49% vs. 72%, P=0.03). In the multivariate analysis, the risk of oral mucositis was related only to the type of chemotherapy regimen, suggesting that further strategies for preventing oral mucositis could be mainly based on these criteria.

Muscle contraction accelerates IL-6 mRNA expression in the rat masseter muscle

OBJECTIVE

This study was conducted to determine if interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) mRNA expression increase in response to muscle contraction caused by repetitive electrical stimulation of the rat masseter muscle.

METHODS

Male Wistar rats weighing 140-160 g were divided randomly into the following three groups: electrical stimulation (ES) group (n=21), carrageenan injection (CI) group (n=24), and ES under dantrolene sodium (muscle relaxant) injection (ESDI) group (n=7). ES or CI was done to the left masseter; and mock ES or mock CI to the right. Muscle tissues on both sides were sampled for total RNA isolation. Real-time RT-PCR was performed, with the cyclophilin A (CypA) mRNA level in each sample as an internal control. Mean relative IL-6 (il-6/cypA) and IL-1beta (il-1beta/cypA) mRNA levels were compared between the experimental and mock-treated sides within each group.

RESULTS

Mean IL-6/CypA levels in the ES- or CI-treated muscle significantly increased, without any significant incremental change observed in either mock-treated muscle. Interestingly, the increase in the il-6/cypA level caused by the ES was suppressed by the injection of dantrolene sodium in the ESDI group. Furthermore, the mean il-1beta/cypA level in the CI-treated masseter also significantly increased without any significant incremental change observed in the mock-treated muscle. However, there was no significant difference in the mean il-1beta/cypA levels in the masseter between the ES- and the mock-treated sides.

CONCLUSIONS

These results show that IL-6 mRNA expression in the rat masseter muscle was accelerated by the CI or by repetitive muscle contraction induced by ES. Since the mRNA level of IL-1beta, a well-known proinflammatory cytokine, was not altered by the contraction, the accelerated IL-6 mRNA expression elicited by the muscle contraction does not seem to be related to local inflammation.

Analysis of the human saliva proteome

Interest in the characterization of the salivary proteome has increased in the last few years. This review discusses the different techniques and methodologies applied to the separation and identification of salivary proteins. Nowadays, proteomic techniques are the state of the art for the analysis of biologic materials and saliva is no exception. 2D electrophoresis and tryptic digest analysis by mass spectrometry are the typical methodology, but new approaches using 2D liquid chromatography/mass spectrometry methods have already been introduced for saliva analysis. Due to their important physiologic role in the oral cavity, low-molecular-weight proteins and peptides are also included in this article and the methodologies discussed.

Effects of autonomic agonists and immunomodulatory cytokines on polymeric immunoglobulin receptor expression by cultured rat and human salivary and colonic cell lines

OBJECTIVE

Immunoglobulin A (IgA) is transported across glandular epithelial cells by polymeric immunoglobulin receptor (plgR), with each receptor molecule participating in only one round of transcytosis. Nerve-related stimuli rapidly increase salivary secretion of IgA, while concentrations are increased in the autoimmune disease Sjögren's syndrome. Our aim here was to determine whether autonomic agonists and cytokines present in Sjögren's-affected glands can up-regulate salivary cell plgR expression.

METHODS

Cultures of rat parotid acinar cells (PAR C5) and human submandibular gland ductal cells (HSG) were exposed to carbachol or adrenaline for 24 h and to interleukin-4 and/or interferon-gamma for 48 h. The human colonic cell line HT-29 served as a positive control for cytokine response. plgR mRNA was quantified by reverse transcription and real-time PCR and protein expression was examined by immunoblotting.

RESULTS

Carbachol increased plgR mRNA levels significantly in all cells but adrenaline did so only with PAR cells (P<0.05). HSG and HT-29 cells both up-regulated plgR gene transcription on exposure to interleukin-4 and interferon-gamma either alone or in combination (P<0.05). By contrast, production of plgR mRNA in PAR cells tended to decrease in response to all cytokine treatments. plgR protein levels rose in line with mRNA expression in cytokine-treated HT-29 cultures (P<0.05).

CONCLUSIONS

Autonomimetics can up-regulate plgR transcription in transformed and neoplastic salivary and colonic cells, although intracellular coupling mechanisms require further investigation. Immunomodulatory cytokines increased plgR expression in one of the salivary cell lines, but additional work is needed to establish whether this occurs in Sjögren's patients.

Salivary sIgA and cortisol: markers for functional dependence in older adults

Elderly persons with health problems and physical limitations have reduced independence. Since poor functional ability is a known risk factor for disease among older populations, including oral disease, this study was undertaken to assess whether salivary defense factors and the stress hormone cortisol are significant markers for functional dependence. Oral examinations; salivary and microbial analyses; and interviews using the Activities of Daily Living (ADD index, the Mini Nutritional Assessment (MNA) and the Perceived Life Stress Questionnaire (PLSQ) were conducted for 123 dentate subjects. Of the subjects, 80 lived independently in the community or in apartments at the Baycrest Centre for Geriatric Care in Toronto, Canada, and 43 resided in the Baycrest nursing home or the Baycrest Hospital. Whole saliva samples were assayed for total secretory immunoglobulin A (sIgA), sIgA1, sIgA2, total protein and cortisol using ELISA. Dependent residents in the nursing home/hospital scored significantly lower in the nutritional assessment, had higher mean PLSQ scores, increased total protein and cortisol concentrations, and reduced salivary flow rates in comparison to ambulatory residents in the community/apartments. In multivariable logistic regression, factors associated with functional dependence were: being male, perceiving income as inadequate, having low salivary flow rate and drinking less than 5 cups of water per day. These results indicate that salivary flow and cortisol may be useful markers of functional dependence; however, the ability of these markers to predict functional decline cannot be confirmed until longitudinal studies are conducted.

Effect of saliva collection method on the concentration of protein components in saliva

In order to clarify how we collect saliva for analyzing salivary protein in aged subjects who can not eat well, we compared the effects of suction, spitting and the swab saliva collection method on the yield of protein components in saliva samples from normal volunteers. The saliva collected by suction, spitting and the swab method were designated as, Saliva I, II and III, respectively. The saliva volume collected by Saliva I was about 2-fold greater than that by of Saliva II and III. This is mainly due to the fact that saliva secretion was stimulated by the suction itself. The content of total protein, S-IgA, trypsin-like activity and human airway trypsin-like protease (HAT) were almost the same in Saliva I and II, and significantly lower in Saliva III than in Saliva I and II. Kallikrein activity was almost the same in Saliva I, II and III. The concentration of each total protein, S-IgA, kallikrein activity, trypsin activity and HAT in Saliva I were significantly positively correlated with that in Saliva II. These results indicate that we can obtain information of change of salivary protein by analyzing saliva collected by suction method, although this method caused the stimulation of saliva to some extent.

Racial differences in salivary sIgA concentrations in postmenopausal women

The purpose of this study was to compare sIgA salivary concentrations between Caucasian and African-American postmenopausal women. The age, height, weight and history of hormone replacement therapy were recorded and the BMI was calculated for each individual. Whole, stimulated saliva was assayed for sIgA and total protein. Logistic regression analysis evaluated the relationships between the outcome variables. Total salivary sIgA and adjusted sIgA (adjusted for protein) concentrations were significantly higher in the African-American women (p<0.01). There were significant statistical correlations between sIgA concentrations and race (p<0.01). Our data suggest that racial differences in salivary sIgA concentrations in elderly women could be an important variable for planning future studies utilizing salivary samples as biological markers.

Biochemical, immunological and enzymatic components of saliva in prolonged naso-gastric-fed elderly patients

BACKGROUND AND AIMS

We have previously shown that naso-gastric tube (NGT)-fed patients harbor pathogenic flora in their oropharynx. The purpose of this study was to examine comparatively the biochemical, immunological and enzymatic components of the saliva of these patients with that of orally-fed counterparts.

METHODS

The study group consisted of 19 elderly NGT-fed patients and 18 comparable patients on oral feeding. Unstimulated whole saliva was collected and analyzed according to accepted methods for sodium, potassium, chloride, uric acid, total protein, albumin, amylase, lysozyme, and immunoglobulins, IgM, IgG, IgA, as well as secretory IgA.

RESULTS

None of the above tested salivary components significantly differed between the two groups. Only uric acid levels were significantly lower (50%, p < 0.05) in NGT-fed patients.

CONCLUSIONS

Uric acid is the main antioxidant component of saliva and, as such, it may be related to pathogenic bacterial colonization of the oropharynx in NGT-fed patients, with the risk of aspiration pneumonia.

Neuroendocrine regulation of salivary IgA synthesis and secretion: implications for oral health

Secretory immunoglobulin A (S-IgA) represents the main adaptive immune mechanism in the oral cavity. The regulation of secretion and synthesis of S-IgA is not only dependent on prior antigenic stimulation, but is also under strong neuroendocrine control. Thus, alterations in neuroendocrine functioning (such as induced by stress, exercise, pregnancy, menstrual cycle, and pharmacological interventions) may affect salivary IgA levels. This review deals with the neuroendocrine regulation of synthesis and secretion of salivary IgA and its potential role in the maintenance of oral health.

Secretion of IgA by rat parotid and submandibular cells in response to autonomimetic stimulation in vitro

The major antibody in saliva is IgA, which is actively transported by pIgR expressed by parenchymal cells within the salivary glands. The rate of IgA secretion into saliva is regulated by the autonomic nerves supplying the glands in vivo. This study examined the mechanism of increased IgA secretion into saliva with autonomimetic stimulation. In vitro stimulation of IgA secretion from cells prepared by digestion of rat salivary glands found submandibular cell preparations responded to alpha- and beta-adrenergic stimuli whereas the parotid cells responded only to beta-adrenergic stimulation, although cells from both glands responded similarly to cholinergic stimulation. The additional responsiveness of submandibular cells to alpha-adrenergic stimulation probably reflects the presence of granular duct cells (absent in parotid glands) which are known to secrete protein in response to high frequency sympathetic stimulation. The increased secretion of IgA was not dependant upon increased plasma cell activation since isolated salivary gland plasma cells did not respond to agonists. Further evidence for the regulating role of parenchymal cells in IgA secretion into saliva was revealed by analysis of polymeric immunoglobulin receptor (pIgR) levels expressed on cells. Following in vivo nerve stimulation, there was an increased amount of pIgR expressed on the membrane surface. This was functionally demonstrated in vitro by increased uptake of human IgA by acutely prepared rat salivary cells following stimulation by adrenaline, indicating increased mobilisation of pIgR with stimulation. This study confirms that salivary cells increase the delivery of IgA into saliva by a pIgR-mediated mechanism in response to autonomic stimulation.

Chronic glutamine supplementation increases nasal but not salivary IgA during 9 days of interval training

Oral glutamine supplementation during and after exercise abolishes exercise-induced decreases in plasma glutamine concentration but does not affect secretory IgA (sIgA) salivary output. Whether chronic glutamine supplementation during high-intensity interval training influences salivary and nasal sIgA concentration is unknown. The purpose of this study was examine the effects of chronic glutamine supplementation on sIgA during intense running training. Runners (n = 13, body mass 69.9 +/- 2.8 kg, peak whole body oxygen uptake 55.5 +/- 2 ml.kg(-1).min(-1), age 29.1 +/- 2.8 yr) participated in twice-daily interval training for 9-9.5 days, followed by recovery (5-7 days). Oral glutamine supplement (0.1 g/kg) or placebo was given four times daily for the first 14 days. After an overnight fast, venous blood, nasal washes, and stimulated saliva were collected at baseline (T1), midtraining (T2), posttraining (T3), and after recovery (T4). Mood states were assessed by using Profile of Mood States (POMS) inventories. We found that glutamine concentration in resting subjects decreased from T1 to T4 (P < 0.05) and was not altered by supplementation. Salivary IgA concentration and output were unchanged by training or supplementation. Mean nasal IgA across the study period was greater in runners receiving glutamine (264.7 +/- 35.0 microg/mg protein) vs. placebo (172.4 +/- 33.7 microg/mg protein; P < 0.05). POMS analyses indicated that vigor was lower at T3 vs. T1 (P < 0.05) and fatigue was higher at T2 vs. T1 and T4 (P < 0.05). We conclude that chronic glutamine supplementation during interval training results in higher nasal IgA than placebo but does not affect salivary IgA concentration or output.