Changes in salivary antimicrobial peptides, immunoglobulin A and cortisol after prolonged strenuous exercise

Impact of exercise on markers of B cell-related immunity: A systematic review

BACKGROUND

B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins. Exercise alters B cell counts and immunoglobulin levels, but evidence-based conclusions on potential benefits for adaptive immunity are lacking. This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells, immunoglobulins, and markers of secretory immunity in human biofluids.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, MEDLINE, Web of Science, and Embase were searched on March 8, 2023. Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions, immunoglobulin levels, salivary flow rate, or secretory immunoglobulin A secretion rate were included. Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise. Study characteristics, outcome measures, and statistically significant changes were summarized tabularly.

RESULTS

Of the 67 eligible studies, 22 applied acute exercise and 45 applied exercise training. All included outcomes revealed significant alterations over time in acute exercise and exercise training context, but only a few investigations showed significant differences compared to control conditions. Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.

CONCLUSION

B cell-related outcomes are altered by acute exercise and exercise training, but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities. Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.

Effects of different exercise intensities or durations on salivary IgA secretion

PURPOSE

This study aimed to examine changes in salivary immunoglobulin A (s-IgA) secretion at different intensities or durations of acute exercise.

METHODS

Twelve healthy untrained young males were included in randomized crossover trials in Experiment 1 (cycling exercise for 30 min at a work rate equivalent to 35%, 55%, and 75% maximal oxygen uptake [ V ˙ O2max]) and Experiment 2 (cycling exercise at 55% V ˙ O2max intensity for 30, 60, and 90 min). Saliva samples were collected at baseline, immediately after, and 60 min after each exercise.

RESULTS

Experiment 1: The percentage change in the s-IgA secretion rate in the 75% V ˙ O2max trial was significantly lower than that in the 55% V ˙ O2max trial immediately after exercise (- 45.7%). The percentage change in the salivary concentration of cortisol, an s-IgA regulating factor, immediately after exercise significantly increased compared to that at baseline in the 75% V ˙ O2max trial (+ 107.6%). A significant negative correlation was observed between the percentage changes in saliva flow rate and salivary cortisol concentration (r = - 0.52, P < 0.01). Experiment 2: The percentage change in the s-IgA secretion rate in the 90-min trial was significantly lower than that in the 30-min trial immediately after exercise (-37.0%). However, the percentage change in salivary cortisol concentration remained the same.

CONCLUSION

Our findings suggest that a reduction in s-IgA secretion is induced by exercise intensity of greater than or equal to 75% V ˙ O2max for 30 min or exercise duration of greater than or equal to 90 min at 55% V ˙ O2max in healthy untrained young men.

Evaluation of salivary α-amylase and immunoglobulin A responses after endurance exercise in adolescent males and females with similar aerobic fitness

The objective of this study was to clarify whether there are sex-specific differences in salivary α-amylase and immunoglobulin A responses following acute endurance exercise in adolescent males and females with equivalent cardiorespiratory fitness levels. Twenty-six aerobically trained adolescent males and females with similar training status were enrolled in this study. Each individual executed a 1-h prolonged cycling exercise corresponding to a constant power output at 65% of peak oxygen uptake. Unstimulated whole salivary samples were taken with the passive drooling method at the 10-min period before and after exercise for the determination of salivary responses [α-amylase, immunoglobulin A, total protein and flow rate]. Salivary α-amylase activity, immunoglobulin A concentration and total protein concentration were significantly augmented immediately after acute endurance exercise. Regarding sex differences, only the salivary flow rate was significantly lower in females than in males. The findings of the present study imply that adolescent males and females appear to have similar salivary responses after acute endurance exercise, as represented by salivary α-amylase activity and immunoglobulin A concentration in connection with total protein concentration and salivary flow rate, when they are matched for peak oxygen uptake relative to fat-free body mass.

Effects of Diabetes and Voluntary Exercise on IgA Concentration and Polymeric Immunoglobulin Receptor Expression in the Submandibular Gland of Rats

Background and Objectives: Patients with diabetes are more susceptible to upper respiratory tract infections (URTIs) because they are easily infected. Salivary IgA (sali-IgA) levels play a major role in transmitting URTIs. Sali-IgA levels are determined by salivary gland IgA production and polymeric immunoglobulin receptor (poly-IgR) expression. However, it is unknown whether salivary gland IgA production and poly-IgR expression are decreased in patients with diabetes. While exercise is reported to increase or decrease the sali-IgA levels, it is unclear how exercise affects the salivary glands of patients with diabetes. This study aimed to determine the effects of diabetes and voluntary exercise on IgA production and poly-IgR expression in the salivary glands of diabetic rats. Materials and Methods: Ten spontaneously diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats (eight-week-old) were divided into two groups of five rats each: a non-exercise group (OLETF-C) and a voluntary wheel-running group (OLETF-E). Five Long-Evans Tokushima Otsuka (LETO) rats without diabetes were bred under the same conditions as the OLETF-C. Sixteen weeks after the study began, the submandibular glands (SGs) were collected and analyzed for IgA and poly-IgR expression levels. Results: IgA concentrations and poly-IgR expression levels in SGs were lower in OLETF-C and OLETF-E than in LETO (p < 0.05). These values did not differ between the OLETF-C and OLETF-E. Conclusions: Diabetes decreases IgA production and poly-IgR expression in the salivary glands of rats. Moreover, voluntary exercise increases sali-IgA levels but does not increase IgA production and poly-IgR expression in the salivary glands of diabetic rats. Increasing IgA production and poly-IgR expression in the salivary glands, which is reduced in diabetes, might require slightly higher-intensity exercise than voluntary exercise under the supervision of a doctor.

Saliva testing as noninvasive way for monitoring exercise-dependent response in teenage elite water polo players: A cohort study

Excessively increased training volume and/or intensity and competition can lead to development of overtraining syndrome, causing a performance decrement in athletes. Tracking individual response to exercise intensity is crucial for establishing recovery strategies.We assessed the exercise intensity-dependent variability of stress response biomarkers, namely cortisol (C), testosterone (T), s-IgA, and advanced oxidation protein products (AOPP), in saliva samples of teenage elite water polo players. Saliva was collected on a day of training match (T1) and a day of competitive match (T2), at morning, before and after match.Cortisol/proteins and testosterone/proteins concentrations decreased throughout day T1, whereas increased throughout day T2. The highest values were measured after match on day T2 (2.5 ± 0.5 vs 14.6 ± 6.3 ng/mg; 0.061 ± 0.024 vs 0.371 ± 0.15 ng/mg, respectively). sIgA/proteins and AOPP/proteins concentrations increased throughout both days, and were higher after T2 match than T1 one (respectively, 1073.0 ± 438.2 vs 71.0 ± 17.3 μg/mg; 78.05 ± 24.2 vs 15.98 ± 3.16 nmol/mg, P = .003). Significant differences between concentrations of different biomarkers recorded on T1 and T2 were found only for AOPP, suggesting an increased oxidative stress on day T2. Free testosterone/cortisol ratio on day T2 was lower than that at morning (0.053 ± 0.021 vs 0.107 ± 0.031), indicating an increased catabolic response after competitive match.A highly significant positive correlation was found between Cortisol/Proteins and Testosterone as well as s-IgA/Proteins on day T1, and between Cortisol/Proteins and AOPP on day T2.In conclusion, we found that different types of activities, such a training or competitive session can affect the hormonal response, immunity, and oxidative stress, thereby modulating athletic performance.Our findings also confirm the usefulness of saliva testing as noninvasive way for monitoring the individual response to changes in exercise intensity in teenage elite water polo players.

Beyond the Finish Line: The Impact and Dynamics of Biomarkers in Physical Exercise-A Narrative Review

The research of biomarkers continues to emerge as a developing academic field which is attracting substantial interest. The study of biomarkers proves to be useful in developing and implementing new screening methods for a wide variety of diseases including in the sports area, whether for leisure activities or professional sports. Novel research has brought into question the immune system and the limitations it may impose on sports practicing. As the well-being of athletes is a priority, the state of their immune function offers valuable information regarding their health status and their ability to continue training. The assessment of various biomarkers may contribute to a more accurate risk stratification and subsequent prevention of some invalidating or even fatal pathologies such as the sudden cardiac death. Therefore, we have reviewed several studies that included sports-related pathology or specific morphofunctional alterations for which some immune biomarkers may represent an expression of the underlying mechanism. These include the defensins, immunoglobulin A (IgA), interleukin-6 (IL-6), the tumoral necrosis factor α (TNF-α), and the white blood cells (WBC) count. Similarly, also of significant interest are various endocrine biomarkers, such as cortisol and testosterone, as well as anabolic or catabolic markers, respectively. Literature data highlight that these values are greatly influenced not only by the duration, but also by the intensity of the physical exercise; moderate training sessions actually enhance the immune function of the body, while a significant increase in both duration and intensity of sports activity acts as a deleterious factor. Therefore, in this paper we aim to highlight the importance of biomarkers’ evaluation in connection with sports activities and a subsequent more adequate approach towards personalized training regimens.

Effect of Multi-Strain Probiotic Supplementation on URTI Symptoms and Cytokine Production by Monocytes after a Marathon Race: A Randomized, Double-Blind, Placebo Study

(1) Purpose: Performing strenuous exercises negatively impacts the immune and gastrointestinal systems. These alterations cause transient immunodepression, increasing the risk of minor infections, especially in the upper respiratory tract. Recent studies have shown that supplementation of probiotics confers benefits to athletes. Therefore, the objective of the current study was to verify the effects of probiotic supplementation on cytokine production by monocytes and infections in the upper respiratory tract after an acute strenuous exercise. (2) Methods: Fourteen healthy male marathon runners received either 5 billion colony forming units (CFU) of a multi-strain probiotic, consisting of 1 billion CFU of each of Lactobacillus acidophilus LB-G80, Lactobacillus paracasei LPc-G110, Lactococcus subp. lactis LLL-G25, Bifidobacterium animalis subp. lactis BL-G101, and Bifidobacterium bifidum BB-G90, or a placebo for 30 days before a marathon. Plasma cytokines, salivary parameters, glucose, and glutamine were measured at baseline, 24 h before, immediately after, and 1 h after the race. Subjects self-reported upper respiratory tract infection (URTI) using the Wisconsin Upper Respiratory Symptom Survey (WURSS-21). The statistical analyses comprised the general linear model (GLM) test followed by the Tukey post hoc and Student's t-test with p < 0.05. (3) Results: URTI symptoms were significantly lower in the probiotic group compared to placebo. The IL-2 and IL-4 plasma cytokines were lower 24 h before exercise, while the other cytokines showed no significant differences. A lower level of IL-6 produced by monocytes was verified immediately after the race and higher IL-10 at 1 h post. No differences were observed in salivary parameters. Conclusion: Despite the low number of marathoners participating in the study, probiotic supplementation suggests its capability to preserve the functionality of monocytes and mitigate the incidence of URTI.

Effect of Tourist Activities on Fecal and Salivary Glucocorticoids and Immunoglobulin A in Female Captive Asian Elephants in Thailand

Simple Summary

How tourist camp activities affect individual elephant welfare is an important and highly debated topic. Saliva and fecal samples were collected monthly for 1 year from 44 female Asian elephants that participated in three programs (saddle-, bareback-, or no-riding), and analyzed for glucocorticoids (GC) and immunoglobulin A (IgA). The hypothesis was that better welfare would be associated with low GC and high IgA concentrations. Both biomarkers showed significant variation with respect to camp size, riding activities, tourist-to-elephant ratios and seasonality, but not always consistently between feces and saliva, and not always in the predicted direction. However, there was no clear indication that riding per se negatively affected these two biomarkers. The lack of consistent responses highlights the difficulty in interpreting physiological data in relation to management factors, and suggests more work is needed to differentiate between potential chronic (feces) and acute (saliva) responses.

Abstract

Asian elephants have been an important part of wildlife ecotourism in Thailand for over two decades. Elephants in tourist camps are exposed to a variety of management styles and daily activities that can potentially affect health and welfare. This study investigated relationships between a novel welfare biomarker, immunoglobulin A (IgA), and daily camp activities, and compared results to glucocorticoid (GC) measures. Often no-riding camps are portrayed as providing better welfare than camps that offer riding. Therefore, we predicted that elephants at no-riding camps would have lower GC and higher IgA concentrations, and a low GC/IgA ratio. Forty-four female elephants from six elephant camps were divided into three groups based on riding activities: saddle-riding, bareback-riding, and no-riding. Fecal and salivary samples were collected monthly for 1 year along with evaluations of body condition, foot health, and wounding. Camp environment and management varied among camps, although the major difference was in riding activities. Concentrations of GCs and IgA varied among the working groups, but not always consistently between sample matrices. Overall fecal glucocorticoid metabolite concentrations were lowest in the saddle-riding group. Only in one bareback-riding camp did the elephants exhibit a potentially positive welfare response with a low GC/IgA ratio over time. Other results varied between the two biomarkers, with considerable variability across camps, suggesting there is more to good welfare than whether elephants participate in riding or not. Several other human-induced stressors, like chaining, ankus use, and limited social opportunities are likely to be impacting well-being and should be considered to ensure management practices meet physical and psychological welfare needs.

HNP-1 and HBD-1 as Biomarkers for the Immune Systems of Elite Basketball Athletes

Acute or strenuous exercise is sometimes related to upper respiratory tract infections in athletes. Practicing intense and regular exercise can lead to incorrect activation of the immune system, causing athletes to be excluded from training programs and competitions. Defensins are small antimicrobial peptides that are part of the innate immune system and dynamically involved in several biological activities. In this study, we highlight the role of human defensins in competitive basketball athletes. In particular, we consider the behavior of alpha- and beta-defensins together with white blood cells in a cohort of players. Moreover, we focus our attention on cortisol, a physiological indicator of stress, and testosterone, both of which are human hormones involved in muscle metabolism. The free-testosterone/cortisol ratio is considered to be an indicator of overtraining among athletes. This paper provides an up-to-date information of the role of human defensins as self-defense molecules during a continuous stressor such as long-term exercise, and it recognizes them as potential markers of infection.

Effects of Carbohydrate Mouth Rinsing on Salivary Lysozyme, Mood States and Running Performance Among Recreational Runners

Introduction

Carbohydrate (CHO) mouth rinsing can enhance sports performance through a central action mediated by receptors in the mouth. This study examined the effect of a CHO mouth rinse on salivary lysozyme concentrations, mood states and running performances.

Methods

Ten males recreational runners were randomised to three running trials with a 1 week recovery period between the trials. Each trial involved running at 75% maximum heart rate (HRmax) for 1 h, followed by a 15 min time trial. The participants used a CHO mouth rinse, placebo (PLA) solution or control (CON, no solution) every 15 min during the exercise. Heart rate (HR), rating of perceived exertion (RPE) and mood states were recorded pre-, during and post-exercise. Saliva samples were collected pre-, post- and 1 h post-exercise.

Results

There was no significant interaction and time effect (P > 0.05) on the salivary lysozyme concentration and running performance, but it was significant (P < 0.05) for HR and RPE (increase in all trials). However, there was no significant difference (P > 0.05) in salivary lysozyme concentrations, running performances, HR values or RPE between the trials. Mood states were not significantly different (P > 0.05) between the trials, but one of the mood sub-scales showed a significant (P < 0.001) time effect (increase fatigue in all trials).

Conclusion

CHO mouth rinsing did not affect physiological parameters, salivary lysozyme concentrations, mood states or running performance among recreational runners.

A high affinity modified DNA aptamer containing base-appended bases for human β-defensin

We used base-appended base modification to develop a new adenine analog, which incorporates an adenine derivative at position 7 of adenine. Using the systematic evolution of ligands by exponential enrichment method with a modified DNA library including this analog, we obtained A^ad1, an aptamer that binds strongly to human β-defensin 2, a biomarker of physical stress found in saliva. The dissociation constant of A^ad1 with respect to human β-defensin 2 was found to be low (6.8 nM), and was found to bind specifically to human β-defensin 2 in saliva spiked with the protein, as confirmed using pull-down with magnetic beads. To our knowledge, there are no prior reports of nucleic-acid aptamers that bind specifically to human β-defensin 2. However, our results indicated that such adenine analog-containing DNA libraries are extremely effective in the acquisition of high-affinity aptamers.

Combined Exercise Modulates Cortisol, Testosterone, and Immunoglobulin A Levels in Individuals Living With HIV/AIDS

BACKGROUND

Combined exercise (CE) has been recommended for individuals living with HIV/AIDS (ILWHA) under antiretroviral therapy. However, depending on the intensity and duration, physical exercise may occasionally increase inflammatory parameters and reduce immunological responses that if not reversed, cause health injury specifically in this population. Information about immunological and hormonal responses after CE in ILWHA has not been completely elucidated. Therefore, the aim is to verify the acute effects of CE on cortisol, testosterone, immunoglobulin A, and pro-inflammatory and anti-inflammatory cytokines over 24 hours in ILWHA.

METHODS

Noninfected individuals and ILWHA undergone 5 sessions of CE prior to the acute assessment session. Seventy-two hours after the last session, the subjects were submitted to one session of CE (aerobic exercise: 25 min at 60-70% reserve heart rate and resistance exercise: 3 sets of 15 maximum repetitions of 6 exercises). Saliva samples were collected before, immediately, 6 and 24 hours after CE.

RESULTS

CE reduced cortisol (6 h: 2.54 [0.58] vs 0.65 [0.22] pg·mL-1; P = .02), increased testosterone (all moments) and immunoglobulin A levels (24 h: 255.3 [44.7] vs 349.2 [41.9] μm·mL-1; P = .01) without significant difference in cytokines levels in ILWHA.

CONCLUSION

CE modulates cortisol, testosterone, and immunoglobulin A levels without the change in immunological parameters in ILWHA.

Influence of acute high-intensity exercise on salivary nitric oxide levels

This study, employing an exercise versus control crossover design, was conducted to investigate the influence of acute high-intensity exercise on salivary nitric oxide (NO) levels. Nine healthy males (aged 23.8 ± 1.4 years) performed ergometer exercise at 80%VO_2peak for 60 min, whereas controls sat at rest for 60 min. Saliva samples were collected before (Pre: 0800 h) and after (Post 0-h: 0900 h, Post 1-h: 1000 h, Post 2-h: 1100 h, Post 3-h: 1200 h) the interventions. Salivary NO levels were determined by colorimetric assay. It was found that the salivary NO levels in controls were decreased (P < 0.05) at Post 0-h (-94 ± 15), Post 1-h (-80 ± 20), Post 2-h (-92 ± 34) and Post 3-h (-145 ± 39) relative to the Pre values. Under exercise conditions, salivary NO levels did not change after high-intensity ergometer exercise relative to the Pre values. Thus, the response of salivary NO levels appeared to differ between high-intensity ergometer exercise and inactivity, that exercise-related stress induces the production of salivary NO.

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.

Immune-endocrine responses and physical performance of master athletes during the sports season

The purpose of this study was to investigate the impact of a training season (approximately 7 months) on physiological and salivary immune-endocrine markers in master athletes. Nine male master athletes were evaluated at the beginning of the season (M1) and a week after the main official competition at the end of the sports season (M2). The controlled variables included Maximal oxygen consumption, anthropometric, physiological, and salivary immune-endocrine markers. Master athletes presented a reduced percentage of fat mass and increased lean body mass at the end of the season. VO_2max values were similar at M1 and M2, while the maximal heart rate and lactate were lower at M2. No differences were observed in Immunoglobulin A and cortisol levels between moments, whereas testosterone levels and the testosterone/cortisol ratio were significantly lower at the end of the season. The results suggest that maintaining regular training throughout life has positive effects on body composition and improves physiological fitness. However, care should be taken to avoid fatigue as indicated by lower testosterone levels at the end of the season.

Salivary extracellular heat shock protein 70 (eHSP70) levels increase after 59 min of intense exercise and correlate with resting salivary secretory immunoglobulin A (SIgA) levels at rest

This study aimed to identify the response of a salivary stress protein, extracellular heat shock protein (eHSP70), to intense exercise and to investigate the relationship between salivary eHSP70 and salivary immunoglobulin A (SIgA) levels in response to exercise. Sixteen healthy sedentary young males (means ± SD 23.8 ± 1.5 years, 172.2 ± 6.4 cm, 68.3 ± 7.4 kg) performed 59 min of cycling exercise at 75% VO2max. Saliva and whole blood samples were collected before (Pre), immediately after (Post), and at 1, 2, 3, and 4 h after completion of the exercise (1, 2, 3, and 4 h). The salivary eHSP70 and SIgA levels were measured by enzyme-linked imunosorbent assay (ELISA), and the secretion rates were computed by multiplying the concentration by the saliva flow rate. White blood cells were analyzed using an automated cell counter with a direct-current detection system. The salivary eHSP70 secretion rates were 1.11 ± 0.86, 1.51 ± 1.47, 1.57 ± 1.32, 2.21 ± 2.04, 3.36 ± 2.72, and 6.89 ± 4.02 ng · min(-1) at Pre, Post, and 1, 2, 3, and 4 h, respectively. The salivary eHSP70 secretion rate was significantly higher at 4 h than that at Pre, Post, 1, and 3 h (p < 0.05). The SIgA secretion rates were 26.9 ± 12.6, 20.3 ± 10.4, 19.6 ± 11.0, 21.8 ± 12.8, 21.5 ± 11.9, and 21.9 ± 11.7 μg · min(-1) at Pre, Post, 1, 2, 3, and 4 h, respectively. The salivary SIgA secretion rate was significantly lower between 1 and 4 h than that at Pre (p < 0.05). There was a positive correlation between salivary eHSP70 and SIgA in both concentration and secretion rates before exercise (p < 0.05). The absolute number of white blood cells significantly increased after exercise, with a maximum at 2 h (p < 0.05). The neutrophil/lymphocyte ratio was significantly increased from 1 to 4 h when compared with that in the Pre samples (p < 0.05). The present study revealed that salivary eHSP70 significantly increased at 4 h after the 59 min of intense exercise in sedentary male subjects. Exercise stress can induce elevated salivary eHSP70 level and upregulate oral immune function partially.

Salivary concentration of the antimicrobial peptide LL-37 in patients with oral lichen planus

Background

The antimicrobial peptide LL-37 is a significant molecule of innate immunity and recent studies indicate that it plays an important role in maintaining oral health. Yet limited knowledge exists on its role in oral diseases and oral lichen planus (OLP) in particular.

Objective

The study aimed to examine: 1) the salivary concentration of LL-37 in patients with OLP and healthy subjects, 2) the relation between the type (reticular or erosive) and size of OLP lesions and LL-37 concentration, and 3) the effect of the therapeutic modalities on LL-37 levels.

Design

The salivary peptide concentration in samples from 20 patients and 30 healthy subjects at the same age range was determined by ELISA.

Results

Despite the wide variation in peptide concentration found in both groups, the healthy subjects exhibited significantly lower levels than patients. Patients with the erosive form had significantly higher peptide concentrations than patients with the reticular form. Systemic treatment with corticosteroids resulted in a significant decrease of the salivary peptide concentration, while other treatment modalities, such as administration of vitamins A and E or local application of corticosteroids had no effect. Improved clinical appearance of the lesions was followed by a decrease in the salivary LL-37 level.

Conclusions

Salivary concentration of LL-37 correlates to the manifestation of mucosa lesions in OLP patients, the highest levels being observed in the most severe cases. This increase in peptide levels may protect against lesion infection and promote a quick wound healing.

A single bout of resistance exercise can enhance episodic memory performance

Acute aerobic exercise can be beneficial to episodic memory. This benefit may occur because exercise produces a similar physiological response as physical stressors. When administered during consolidation, acute stress, both physical and psychological, consistently enhances episodic memory, particularly memory for emotional materials. Here we investigated whether a single bout of resistance exercise performed during consolidation can produce episodic memory benefits 48 h later. We used a one-leg knee extension/flexion task for the resistance exercise. To assess the physiological response to the exercise, we measured salivary alpha amylase (a biomarker of central norepinephrine), heart rate, and blood pressure. To test emotional episodic memory, we used a remember-know recognition memory paradigm with equal numbers of positive, negative, and neutral IAPS images as stimuli. The group that performed the exercise, the active group, had higher overall recognition accuracy than the group that did not exercise, the passive group. We found a robust effect of valence across groups, with better performance on emotional items as compared to neutral items and no difference between positive and negative items. This effect changed based on the physiological response to the exercise. Within the active group, participants with a high physiological response to the exercise were impaired for neutral items as compared to participants with a low physiological response to the exercise. Our results demonstrate that a single bout of resistance exercise performed during consolidation can enhance episodic memory and that the effect of valence on memory depends on the physiological response to the exercise.

Effects of aerobic exercise on lipid-effector molecules of the innate immune response

INTRODUCTION

Consistent, moderate-to-vigorous-intensity exercise has been associated with a lower risk of upper respiratory tract infection (URI). However, the molecular basis for this apparent protection has not yet been fully resolved. Host-derived lipids such as cholesteryl esters (CE) have emerged as important effector molecules of innate defense against infections. Here, we compared antimicrobial CE in nasal fluid before and after moderate-to-vigorous exercise between active and inactive subjects.

METHODS

Nasal fluid was collected from 14 healthy, recreationally active subjects (32 ± 11 yr, 7 men and 7 women) and 14 healthy, inactive subjects (25 ± 3 yr, 7 men and 7 women) before and after treadmill exercise at 70% heart rate reserve. Nasal fluid was analyzed for lysozyme, cholesteryl linoleate (CL), cholesteryl arachidonate (CA), and albumin (Alb) concentrations.

RESULTS

Baseline concentrations (mean ± SEM, inactive vs active) of lysozyme (117.7 ± 31.1 vs 122.9 ± 15.5 μg·mL), CL + CA (15.3 ± 1.8 vs 26.2 ± 10.05 μg·mL), and Alb (156.6 ± 54.5 vs 126.9 ± 32.8 μg·mL) were similar to previously reported levels and did not differ significantly between study groups. However, postexercise, CL + CA concentration was significantly lower in inactive compared with active subjects (7.8 ± 1.5 vs 20.1 ± 4.8 μg·mL, P = 0.036) dropping below the antimicrobial effective range. Once adjusted to Alb concentrations, the changes were no longer significant, suggesting that plasma transudation accounted for the increased CA + CL concentration postexercise in the active group relative to the inactive group.

CONCLUSIONS

Moderate-to-vigorous aerobic exercise acutely decreases the antimicrobial CE response in inactive subjects but does not modify baseline levels of CE between active and inactive subjects. This suggests that compared with active individuals, inactive individuals may be at greater risk for upper respiratory tract infection immediately postexercise.

Baker's yeast beta glucan supplementation increases salivary IgA and decreases cold/flu symptomatic days after intense exercise

Strenuous exercise, such as running a marathon, is known to suppress mucosal immunity for up to 24 hr, which can increase the risk of developing an upper respiratory tract infection (URTI) and reduced performance capacity (Allgrove JE, Geneen L, Latif S, Gleeson M. Influence of a fed or fasted state on the s-IgA response to prolonged cycling in active men and women. Int J Sport Nutr Exerc Metab. 2009;19(3):209–221; Barrett B, Locken K, Maberry R, Schwamman J, Brown R, Bobula J, Stauffacher EA. The Wisconsin Upper Respiratory Symptom Survey (WURSS): a new research instrument for assessing the common cold. J Fam Pract. 2002;51(3):265; Carpenter KC, Breslin WL, Davidson T, Adams A, McFarlin BK. Baker's yeast beta glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk? Br J Nutr. 2012;1–9). While many dietary interventions have been used to combat postexercise immune suppression, most have been ineffective. The key purpose of this study was to determine if baker's yeast β-glucan (BG) could positively affect the immune system of individuals undergoing intense exercise stress using two experiments. In the first (E1; N = 182 men and women), BG was compared to placebo supplementation for the incidence of URTI symptoms for 28 days postmarathon. In the second (E2; N = 60 men and women) changes in salivary immunoglobulin A (IgA) were evaluated after 50-min of strenuous cycling when participants had been supplemented for 10 days with either BG (250 mg/day) or placebo (rice flour). For E1, subjects reported URTI symptoms using a daily health log. For E2, saliva was collected prior to, immediately, and 2-hr postexercise using a salivette. Data for E1 and E2 were analyzed using separate analyses of variance (ANOVAs) with repeated measures (p < .05). In E1, BG was associated with a 37% reduction in the number of cold/flu symptom days postmarathon compared to placebo (p = .026). In E2, BG was associated with a 32% increase in salivary IgA (p = .048) at 2 hr after exercise compared to placebo. In summary, the present study demonstrates that BG may reduce URTI symptomatic days and improve mucosal immunity (salivary IgA) postexercise.

Effects of yoga exercise on salivary beta-defensin 2

PURPOSE

Yoga stretching can be done comfortably and easily by beginners and older adults to compensate for lack of exercise or poor health maintenance. The aim of this study was to determine the effect of yoga stretching on mucosal immune functions, primarily human β-defensin 2 (HBD-2) in saliva.

METHODS

Fifteen healthy adults (age, 60.4 ± 8.0 years) participated in the study. Participants rested for 90 min on the first day and performed yoga for 90 min on the second day. Measurements were carried out before and after rest or yoga. Saliva samples were collected by chewing a sterile cotton at a frequency of 60 cycles per min. Salivary HBD-2 concentration was measured using an enzyme-linked immunosorbent assay.

RESULTS

HBD-2 concentration after yoga stretching (165.4 ± 127.1 pg/mL) was significantly higher than that before yoga stretching (84.1 ± 63.4 pg/mL; p < 0.01). HBD-2 expression rate after yoga stretching (232.8 ± 192.9 pg/min) was significantly higher than that before yoga stretching (110.7 ± 96.8 pg/min; p < 0.01). HBD-2 concentration (p < 0.05) and HBD-2 expression rate (p < 0.01) at post on the second day (yoga) was significantly higher than that on the first day (rest). POMS score of anger-hostility was lower after yoga than before.

CONCLUSIONS

Yoga stretching for 90 min can increase salivary HBD-2 expression in older adults. Therefore, yoga stretching might be useful for older adults and athletes to maintain their health.

Salivary concentration of free LL-37 in edentulism, chronic periodontitis and healthy periodontium

OBJECTIVE

The antimicrobial peptide LL-37, a component of innate immunity, has an important role in maintaining oral health. This study aimed to investigate the concentration of free LL-37 in whole saliva of periodontally healthy, edentulous and chronic periodontitis subjects.

DESIGN

Unstimulated whole saliva was sampled from 154 subjects (76 periodontally healthy, 20 edentulous, and 58 subjects with chronic periodontitis). All participants were in good general health. The salivary LL-37 was determined by ELISA.

RESULTS

The median salivary concentrations of free LL-37 were 30.5, 22.5, and 1.8ng/ml for the healthy, the chronic periodontitis and the edentulous group, respectively. The differences in concentration between the edentulous and the others were statistically significant (Mann-Whitney test, p<0.001). In the healthy subjects, women displayed significantly higher peptide concentrations compared to men (Mann-Whitney test, p<0.05). The intra-subject variation in LL-37 concentration was wider for the healthy (range 0.75-285ng/ml) and chronic periodontitis patients (range 1-207ng/ml) than for the edentulous subjects (range 0.15-4.4ng/ml).

CONCLUSIONS

The present findings show that edentulism correlates with a substantial decrease in salivary levels of free LL-37, thus indicating the considerable contribution of the gingival tissues in the secretion of the peptide in the oral environment.