Acute psychosocial stress differentially influences salivary endocrine and immune measures in undergraduate students

Biosensors based on organic transistors for intraoral biomarker detection

Intraoral biomarkers are important indicators for the diagnosis and prediction of oral and systemic diseases. Among various intraoral biomarkers, the biomarkers in saliva have been the main focus of research, due to their abundance, non-invasiveness, and correlation with health status. Nonetheless, detecting low-abundance intraoral biomarkers poses significant challenges, and the conventional assays are unsuitable for swift large-scale analysis due to their complex procedures. Hence, an immediate demand arises for innovative methods to supplant traditional assay techniques. Organic transistor-based biosensors have emerged as promising devices for the detection of these intraoral biomarkers, especially in point-of-care (POC) settings. These biosensors offer advantages such as high sensitivity, selectivity, ease of integration, and biocompatibility. This review provides an overview of the evolution and utilization of biosensors that rely on functional organic transistors, with a focus on electrolyte-gated organic field-effect transistors (EGOFETs) and organic electrochemical transistors (OECTs). First, the working principles and sensing mechanisms of various organic transistors are summarized. Then, recent progress and challenges in developing organic transistor-based biosensing platforms for detecting intraoral biomarkers are summarized, along with examples from representative studies. Last, prospects and opportunities for the advancement of organic transistor-based biosensors for oral health monitoring are discussed.

Acute Stress and Autoimmune Markers: Evaluating the Psychoneuroimmunology Axis in Firefighter Recruits

Chronic psychological stress is known to influence immune function and contribute to development of autoimmune disorders through dysregulated inflammatory responses. This study investigates relationships between acute stress, life trauma, and autoimmune salivary biomarkers in firefighter recruits during psychophysical stress training. Salivary samples were collected from firefighter recruits during two stress tests to evaluate responses to acute stress. Samples were obtained at three time points-pre-stress, post-stress, and recovery-across both tests. Cortisol was measured to characterize acute stress response (ASR) profiles, while immune function was assessed through the analyzing C-reactive Protein (CRP), Complement C4 (C4), Pigment Epithelium Derived Factor (PEDF), and Serum Amyloid P (SAP). Results showed significant changes in CRP, C4, and PEDF after stress inoculation. Higher previous life trauma was associated with lower baseline cortisol (r = -0.489) and delay in cortisol recovery (r = 0.514), suggesting a learned biological response, potentially protective against stress-induced dysregulation. Cluster analysis revealed four distinct cortisol ASR profiles which were found to have significantly different past life trauma (p = 0.031). These findings suggest that trauma history influences stress biomarker dynamics, potentially reflecting individualized adaptive or maladaptive responses. The insights gained may inform strategies to enhance stress resilience and mitigate autoimmune risk among high-stress populations.

Changes in the choice motive and emotional perception of chocolates in response to stress

Although chocolates are often chosen for sensory pleasure, they are also selected to enhance mood and relieve emotional stress, or potentially chosen for its perceived health benefits if stress adversely affects physical well-being. This study aimed to investigate whether emotional stress influenced the motivations behind chocolate selection, subsequent liking, and emotional response. Participants were divided into a control group (n = 76) and a group with induced acute stress (n = 74). Stimuli were presented as dark chocolate packaging, each evoking sensory appeal, health, and emotional stress relief. Participants chose one stimulus from three options that they were most inclined to consume and evaluated the overall liking and emotional attributes of the stimuli. They also rated the overall liking and emotional attributes of three types of chocolates, each identical but paired with distinct stimuli. Their food attitudes were also assessed. Stress did not change the choice of stimuli, indicating that stress did not influence the motivation for chocolate selection. Instead, the choice of stimuli aligned with participants' food attitudes; those favoring sensory appeal and emotional stress relief prioritized pleasure in their usual food choices. Stress tended to increase liking and chocolate-associated positive emotions with sensory appeal, as opposed to others, to immediately alleviate negative emotions. The most robust motivation to consume chocolates was sensory pleasure, irrespective of stress, because of a preestablished association between sensory pleasure and mood enhancement.

Salivary secretory immunoglobulin A as a potential biomarker of psychosocial stress response during the first stages of life: A systematic review

Mucosal secretory immunoglobulin A (s-IgA) has been recognized as a key component of human first line defense against infection. However, its reactivity to psychosocial stressors is poorly understood. This systematic review aimed to explore whether s-IgA levels changed after psychosocial stress in subjects under the age of 18. Fifteen articles were included. s-IgA basal levels are increased in children older than 9 years old exposed to stress. Furthermore, s-IgA seems to follow a circadian rhythm, which is altered under stress conditions. Finally, the collective evidence suggests that salivary s-IgA rapidly increases under acute stress after puberty. Overall, our review indicates that s-IgA could be considered a potential psychosocial stress biomarker of interest for pediatric and child-juvenile psychiatric population. Further studies are needed to validate the role of s-IgA circadian rhythm and basal levels as psychosocial stress biomarkers and disentangle the role of age and type of stressor.

Ecoimmunology in the field: Measuring multiple dimensions of immune function with minimally invasive, field-adapted techniques

OBJECTIVE

Immune function is multifaceted and characterizations based on single biomarkers may be uninformative or misleading, particularly when considered across ecological contexts. However, measuring the many facets of immunity in the field can be challenging, since many measures cannot be obtained on-site, necessitating sample preservation and transport. Here we assess state-of-the-art methods for measuring immunity, focusing on measures that require a minimal blood sample obtained from a finger prick, which can be: (1) dried on filter paper, (2) frozen in liquid nitrogen, or (3) stabilized with chemical reagents.

RESULTS

We review immune measures that can be obtained from point-of-care devices or from immunoassays of dried blood spots (DBSs), field methods for flow cytometry, the use of RNA or DNA sequencing and quantification, and the application of immune activation assays under field conditions.

CONCLUSIONS

Stable protein products, such as immunoglobulins and C-reactive protein are reliably measured in DBSs. Because less stable proteins, such as cytokines, may be problematic to measure even in fresh blood, mRNA from stabilized blood may provide a cleaner measure of cytokine and broader immune-related gene expression. Gene methylation assays or mRNA sequencing also allow for the quantification of many other parameters, including the inference of leukocyte subsets, though with less accuracy than with flow cytometry. Combining these techniques provides an improvement over single-marker studies, allowing for a more nuanced understanding of how social and ecological variables are linked to immune measures and disease risk in diverse populations and settings.

Effects of olfactory stimulus on group performance and individual stress responses in university students

Group work is essential in professional settings to encourage effective communication and optimize outcomes. Stress can reduce teamwork effectiveness and aromatherapy might be able to reduce feelings of stress/anxiety in individuals. However, it is unclear if aromatherapy impacts stress levels or performance during group activities. Therefore, we examined if essential oil exposure impacted stress responses and performance of individuals and groups during a team-based task involving a challenging medical decision. Subjects (n = 36) were part of a 3-person group (12 groups total) that completed a timed moral reasoning dilemma wearing a mask that contained a purported stimulatory essential oil (peppermint), a purported relaxing essential oil (lavender) or masks that contained neither odor (3 groups/mask type). Heart rate (HR) responses were recorded continuously before, during and after the task. The time to complete the task, decision making during the task, and subject's perceptions of the task were also recorded. Control subjects and subjects exposed to peppermint demonstrated a significant stress-induced increase in HR during the group task. However, subjects exposed to lavender demonstrated a significantly attenuated HR. Subjects in the control group who perceived high stress levels during the task demonstrated further elevations in HR than those not reporting stress, however, this pattern was not observed in subjects exposed to either essential oil. Groups did not differ in the time required to complete the task although only the groups exposed to lavender used decision making consistent with medical practice. Therefore, exposure to lavender was associated with differential physiological responses during a stressful group task, potentially due to olfactory system stimulation of anxiolytic and/or trust promoting central nervous system pathways. Aromatherapy might be a useful tool in group settings to mitigate the impact of stress and improve group performance.

Secretory immunoglobulin A (s-IgA) reactivity to acute psychosocial stress in children and adolescents: The influence of pubertal development and history of maltreatment

BACKGROUND

Mucosal secretory immunoglobulin A (s-IgA) is an antibody protein-complex that plays a crucial role in immune first defense against infection. Although different immune biomarkers have been associated with stress-related psychopathology, s-IgA remains poorly studied, especially in youth.

OBJECTIVES

The present study investigated how s-IgA behaves in front of acute psychosocial stress in children and adolescents, including possible variability associated with developmental stage and history of childhood maltreatment (CM).

METHODS

94 children and adolescents from 7 to 17 years (54 with a current psychiatric diagnostic and 40 healthy controls) drawn from a larger Spanish study were explored (EPI-Young Stress Project). To assess biological reactivity, participants provided five saliva samples during an acute laboratory-based psychosocial stressor, the Trier Social Stress Test for Children (TSST-C). Samples were assayed for s-IgA, as well as for cortisol. Pubertal development was ascertained by Tanner stage and CM following TASSCV criteria.

RESULTS

We observed s-IgA fluctuations throughout the stressor, indicating the validity of TSST-C to stimulate s-IgA secretion (F(4,199) = 6.200, p <.001). Although s-IgA trajectories followed a reactivity and recovery pattern in adolescents, children exhibited no s-IgA response when faced with stress (F(4,197) = 3.406, p =.010). An interaction was found between s-IgA and CM (F(4,203) = 2.643, p =.035). Interestingly, an interaction between developmental stage, CM history and s-IgA reactivity was identified (F(12,343) = 2.036, p =.017); while children non-exposed to maltreatment exhibited no s-IgA changes to acute stress, children with a history of CM showed a similar response to adolescents, increasing their s-IgA levels after the psychosocial stressor.

CONCLUSION

Acute psychosocial stress stimulates s-IgA secretion, but only after puberty. However, children with a history of maltreatment exhibited a response resembling that of adolescents, suggesting an early maturation of the immune system. Further studies are needed to clarify the validity of s-IgA as an acute stress biomarker, including additional measures during stress exposure.

Cortisol and C-Reactive Protein Vary During Sleep Loss and Recovery but Are Not Markers of Neurobehavioral Resilience

Cortisol and C-reactive protein (CRP) typically change during total sleep deprivation (TSD) and psychological stress; however, it remains unknown whether these biological markers can differentiate robust individual differences in neurobehavioral performance and self-rated sleepiness resulting from these stressors. Additionally, little is known about cortisol and CRP recovery after TSD. In our study, 32 healthy adults (ages 27-53; mean ± SD, 35.1 ± 7.1 years; 14 females) participated in a highly controlled 5-day experiment in the Human Exploration Research Analog (HERA), a high-fidelity National Aeronautics and Space Administration (NASA) space analog isolation facility, consisting of two baseline nights, 39 h TSD, and two recovery nights. Psychological stress was induced by a modified Trier Social Stress Test (TSST) on the afternoon of TSD. Salivary cortisol and plasma CRP were obtained at six time points, before (pre-study), during [baseline, the morning of TSD (TSD AM), the afternoon of TSD (TSD PM), and recovery], and after (post-study) the experiment. A neurobehavioral test battery, including measures of behavioral attention and cognitive throughput, and a self-report measure of sleepiness, was administered 11 times. Resilient and vulnerable groups were defined by a median split on the average TSD performance or sleepiness score. Low and high pre-study cortisol and CRP were defined by a median split on respective values at pre-study. Cortisol and CRP both changed significantly across the study, with cortisol, but not CRP, increasing during TSD. During recovery, cortisol levels did not return to pre-TSD levels, whereas CRP levels did not differ from baseline. When sex was added as a between-subject factor, the time × sex interaction was significant for cortisol. Resilient and vulnerable groups did not differ in cortisol and CRP, and low and high pre-study cortisol/CRP groups did not differ on performance tasks or self-reported sleepiness. Thus, both cortisol and CRP reliably changed in a normal, healthy population as a result of sleep loss; however, cortisol and CRP were not markers of neurobehavioral resilience to TSD and stress in this study.

Trier Social Stress Test Elevates Blood Pressure, Heart Rate, and Anxiety, But a Singing Test or Unsolvable Anagrams Only Elevates Heart Rate, among Healthy Young Adults

The Trier Social Stress Test (TSST) is a psychosocial stressor that effectively stimulates the stress response but is labor and time intensive. Although other psychological stressors are often used experimentally, none are known to comparably elevate stress. Two stressors that may potentially elevate stress are a singing task (ST) and unsolvable anagrams, but there are not enough data to support their effectiveness. In the current experiment, 53 undergraduate males and females (mean age = 21.9 years) were brought into the laboratory, and baseline blood pressure, heart rate, self-rated anxiety, and salivary cortisol were recorded. Then, participants were randomly assigned to one of three stress conditions: TSST (n = 24), ST (n = 14), or an unsolvable anagram task (n = 15). Stress measures were taken again after the stressor and during recovery. The TSST significantly elevated systolic blood pressure, diastolic blood pressure, heart rate, and self-rated anxiety from pre-stress levels, replicating its stress-inducing properties. However, the ST and unsolvable anagrams only elevated heart rate, indicating that these methods are not as able to stimulate physiological or psychological stress. Overall, results indicate that out of these three laboratory stressors, the TSST clearly engages the stress response over the ST or unsolvable anagrams.

Salivary Proteome Changes in Response to Acute Psychological Stress Due to an Oral Exam Simulation in University Students: Effect of an Olfactory Stimulus

The autonomic nervous system (ANS) plays a crucial role both in acute and chronic psychological stress eliciting changes in many local and systemic physiological and biochemical processes. Salivary secretion is also regulated by ANS. In this study, we explored salivary proteome changes produced in thirty-eight University students by a test stress, which simulated an oral exam. Students underwent a relaxation phase followed by the stress test during which an electrocardiogram was recorded. To evaluate the effect of an olfactory stimulus, half of the students were exposed to a pleasant odor diffused in the room throughout the whole session. Saliva samples were collected after the relaxation phase (T0) and the stress test (T1). State anxiety was also evaluated at T0 and T1. Salivary proteins were separated by two-dimensional electrophoresis, and patterns at different times were compared. Spots differentially expressed were trypsin digested and identified by mass spectrometry. Western blot analysis was used to validate proteomic results. Anxiety scores and heart rate changes indicated that the fake exam induced anxiety. Significant changes of α-amylase, polymeric immunoglobulin receptor (PIGR), and immunoglobulin α chain (IGHA) secretion were observed after the stress test was performed in the two conditions. Moreover, the presence of pleasant odor reduced the acute social stress affecting salivary proteome changes. Therefore, saliva proteomic analysis was a useful approach to evaluate the rapid responses associated to an acute stress test also highlighting known biomarkers.

Examining the role of ethnic microaggressions and ethnicity on cortisol responses to an acute stressor among young adults

Objective: This study examined whether the frequency of experiences of ethnic microaggressions and the sensitivity to such experiences were associated with cortisol responses to an acute social stressor (Trier Social Stress Test; TSST) among an ethnically diverse sample of young adults (N = 109, Mage = 18.82 years, SD = 1.40 years, 74% female, 44% Latinx). Method: Self-reported experiences of and sensitivity to microaggressions were assessed using the Everyday Microaggressions Scale. Participants' salivary cortisol was collected before, immediately after, and at three 15-min intervals after the TSST (for a total of 5 salivary samples) to assess their cortisol responses to an acute social stressor. Results: Mixed model analyses revealed that experiencing a higher frequency of microaggressions (p = .005) and being more sensitive to those experiences (p = .001) were associated with a more blunted cortisol response (i.e., lower cortisol reactivity and recovery) to the TSST, relative to experiencing a lower frequency of microaggressions and being less sensitive to them. Furthermore, this blunted cortisol response to the TSST was more prominent among young adults of Latinx and other ethnic backgrounds (i.e., biracial, African American, and Native American) compared to their Asian American and non-Hispanic White peers (p = .034). Conclusion: Findings provide insight into the different ways in which experiences of ethnic microaggressions can be associated with biological markers of stress. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Salivary inflammatory cytokines echo the low inflammatory burden in liver-transplanted children

OBJECTIVES

The aims of this study were to compare the salivary cytokine profile, as a potential replacement for blood tests, in liver-transplanted children to that of a control group of healthy children, and to correlate the values of commonly tested laboratory blood tests to those of published blood values.

METHODS

Liver-transplanted children, and a control group of healthy children of the same sex and age distribution, were recruited for the study. Saliva was collected at the same appointment for routine blood tests for the liver-transplanted children. Saliva was also collected from a control group of healthy children with similar age and sex distributions. Normal healthy blood values were extracted from the literature, for comparison. Cytokine levels in the saliva were quantified with ELISA. The analysis compared serum and saliva values between liver-transplanted and healthy children. In the serum, the values of albumin, GIT, GPT, GGT, CRP, WBC, neutrophils, and lymphocytes were examined, while the levels of IL-6, CXCL1, IL-1b, and IL-10 were measured in the saliva.

RESULTS

Thirty liver-transplanted children and 30 healthy children were included in the study. Compared with published data for healthy children, the liver-transplanted group showed similar hepatic serum levels, yet reduced levels of serum inflammatory markers. Compared with the control group, in the transplanted group, the mean value of IL-6 was lower and the mean value of CXCL1 was similar. Interestingly, the anti-inflammatory IL-10 cytokine was lower in the transplanted group, while the pro-inflammatory IL-1β cytokine was higher.

CONCLUSION

The salivary inflammatory markers examined showed a similar pattern to the serum inflammatory values, though different markers were examined in the serum and saliva.

CLINICAL RELEVANCE

The current study stresses the potential of oral fluids as an accessible biofluid, for use as a diagnostic substrate for systemic and oral diseases.

TRIAL REGISTRATION

0136-16-RMC, Registered on 01 March 2018.

Social media use following exposure to an acute stressor facilitates recovery from the stress response

Recent evidence indicates that social network use (e.g., Facebook) prior to exposure to an acute stressor can buffer the physiological response to that stressor. However, it is unclear if using social media after exposure to an acute stressor can modulate recovery following the stressor. In the current study, therefore, we examined if social media use might serve as an effective coping mechanism to help deal with exposure to a stressor. Heart rate, blood pressure, and salivary cortisol were compared in healthy college undergraduates (n = 23) before and after completion of the Trier Social Stress Test (TSST). Following exposure to the TSST, subjects were selected to use social media, read quietly or given the choice to use social media or read quietly during a 15- minute recovery period. The TSST induced significant increases in heart rate, systolic blood pressure, and salivary cortisol. Additional analyses revealed that subjects that used social media after termination of the acute stressor demonstrated a significantly facilitated hemodynamic and a trend for a more rapid endocrine recovery compared with subjects that read quietly during the recovery period. Although the majority (71%) of subjects given the choice of recovery modality chose to use social media, differences were not observed between groups selected to use social media and those given the choice to do so during the recovery period. These results suggest that sympathetic nervous system and hypothalamic-pituitary-adrenal axis recovery following stimulation by an acute stressor might be modulated by social media use in undergraduates. Collectively, these data provide further insight into the interaction between psychosocial stress, social media use and health.

Sex differences in heart rate responses to occupational stress

Cardiovascular disease (CVD) remains the leading cause of disease burden globally and chronic stress is associated with increased risk of CVD. Recognition of chronic occupational stressors as a potential contributor to CVD highlights the need to recognize and prevent stress during work. The ubiquity of wearable technology devices to monitor health provides a new opportunity to noninvasively examine the cardiovascular system throughout a work shift. In the current study, we examined changes in heart rate (HR) during a work shift in a retail store setting using 23 healthy female and male subjects that differed in their physical fitness status. Subjects had their HR tracked via an Apple Watch during three typical work shifts. The results demonstrated an increase in HR during a work shift to a level observed during a moderate stressor (resting HR = 83.2 BPM ± 7.8; highest HR mean = 109.1 BPM ± 11.7; p < .0001). Female subjects demonstrated a significantly elevated maximum HR, a larger change in HR, and a larger percent change in HR compared with males (all p < .05). Physical activity status did not influence the observed changes in HR for females or males. Neither the time of day the work shift occurred nor the length of the shift modulated the observed pattern of HR changes. Collectively, our findings demonstrate the potential for wearables in biomedical research and personalized health.

Distraction-focused interventions on examination stress in nursing students: Effects on psychological stress and biomarker levels. A randomized controlled trial

BACKGROUND

Nursing students all over the world experience high levels of stress with negative impacts on their health, emotional state and performance.

AIM

This study aimed to investigate the effects of distraction-focused interventions on examination stress and anxiety in nursing students.

METHODS

A randomized controlled, parallel trial design was conducted from January to June 2016. After baseline measurement, 72 participants were randomized to one of the following groups (n = 18 each): (i) animal-assisted therapy; (ii) music therapy; (iii) mandala painting; (iv) control group. Outcomes of all groups in terms of stress-reduction were compared by measuring self-reported perceived stress (STAI-State and visual analogue stress scale) and salivary biomarker levels (Cortisol and Immunoglobulin A).

RESULTS

Fifty-seven complete data sets (n = 12-16 for each group) were analysed. All distraction-focused interventions showed stress and anxiety reduction in everyday school situations. By contrast, on days with examinations, stress reductions did not reach statistical significance in regard to self-reported psychological stress. At the same time, interventions resulted in significantly decreased levels of stress biomarkers (P < .001).

CONCLUSIONS

Our preliminary findings suggest positive but situation-dependent effects of distraction-focused interventions in academic settings. Further research should investigate the complex relationship between physiological and psychological stress parameters.

An inactive control of the 'Trier Social Stress Test' for Youth 10-17 years: Neuroendocrine, cardiac, and subjective responses

The Trier Social Stress Test for children (TSST-C) adapted from TSST is one of the most commonly used laboratory paradigms for investigating the effects of stress on cognitive, affective and physiological responses in children and adolescents. Considering that laboratory procedures generate a significant amount of stress to children and adolescents, even in the absence of a stress paradigm, it is important to validate TSST-C against an inactive control condition in which the stress components were absent. Using a randomized design, we tested an inactive control condition, which replaced the TSST-C with a benign video clip (nature scenes viewed while standing), thus removing the stress associated components of the TSST-C. Eighty-eight youth between the ages of 10 and 17 years were randomly assigned to complete the TSST-C or the Inactive Control (IC). Subjective anxiety rating, salivary cortisol, systolic and diastolic blood pressure, and heart rate were collected at eight time points. Subjects in the Inactive Control condition showed no significant changes in blood pressure and heart rate, and decreased anxiety rating and salivary cortisol level throughout the study. Subjects in the stress condition (TSST-C) showed increased anxiety ratings, salivary cortisol, systolic and diastolic blood pressure, and heart rate immediately following TSST-C stress induction. Our findings validated that the TSST-C induced a systemic stress response, and that the Inactive Control can be a promising standardized control condition for the TSST-C and a tool for future psychobiological research. Our results also showed that anxiety reactivity decreased with age while HR reactivity increased with age. Cortisol reactivity did not fall in a linear relationship with age but rather via a quadratic curve, suggesting the mid-age adolescents had the highest cortisol responses to stress compared to their younger and older peers, potentially due to a dual factor of pubertal development and self-control and emotion regulation capacity.

Physical Activity versus Psychological Stress: Effects on Salivary Cortisol and Working Memory Performance

Background and Objective: The present study was designed to investigate whether acute physical activity and psychological stress produce different effects on cortisol release and working memory performance. Materials and Methods: Male subjects (N = 12; 18–35 years) were recruited and scheduled to come four times to our lab (within-subject design). For each counterbalanced visit, they performed one of the following four protocols: control, moderate physical activity (MOD), vigorous physical activity (VIG), and acute stress. Heart rate was monitored during every protocol. MOD and VIG were performed for 15 min and were defined as 40–50% and 70–80%, respectively, of their maximum heart rate. Acute stress was imposed via the Trier Social Stress Test (TSST). Salivary samples were collected before and after every protocol to assess cortisol concentrations. Working memory (WM) performance was evaluated through the 2N-Back task right after ending the protocol (early WM) and after a delay of 35 min (late WM). Results: VIG and stress, but not MOD, increased salivary cortisol concentrations. However, the increases of cortisol produced by VIG and stress were not significantly different. Also, there were no significant differences in working memory performance (late and early) in any of the experimental protocols tested. Conclusions: These results show that exercise (VIG) and stress produce similar effects on cortisol release and do not support the hypothesis that working memory capacity is influenced by elevated cortisol levels, either from varying exercise intensities or psychological stress.

Salivary secretory immunoglobulin A reactivity: a comparison to cortisol and α-amylase patterns in the same breast cancer survivors

Introduction

One way to examine the extent to which the stress associated with a breast cancer experience (BC) impacts stress-related physiological mechanisms is to study the secretion patterns of associated biomarkers. Unlike cortisol and α-amylase (sAA), biomarkers of immune functioning such as secretory immunoglobulin A (SIgA) have rarely been examined in BC survivors.

Aim of the study

This study had two principal aims: the first was to evaluate the basal secretion profiles of SIgA as well as its response to an acute stressor as a marker of immune health in BC survivors and women with no history of BC, and the second was to determine how SIgA stress-related patterns compare to published cortisol and sAA patterns in the same women.

Results

Overall, the findings indicate that BC survivors exhibit a blunted cortisol reaction to an acute stressor, a generally elevated diurnal sAA concentration pattern, and normal SIgA profiles, compared to women with no history of cancer. This study serves as a foundation for future research to elucidate the relationships between BC experience variables, stress biomarkers, and health outcomes in BC survivors.

High heart rate reactors display greater decreases in tear SIgA concentration following a novel acute stressor

Tear secretory immunoglobulin-A (SIgA) is a putative biomarker of common-cold risk with potential utility in non-invasive diagnostics. As SIgA secretion at the ocular surface is under strong autonomic control, we investigated the relationship between HR reactivity and tear SIgA responses to novel experiential stress. Thirty-two healthy participants undertook a 60 s zip-line ride to evoke acute stress and a seated-rest control trial in a randomised-crossover design. We recorded heart rate (HR) continuously and collected unstimulated tear samples 5 min pre-, 2 min post- and 20 min post-stress/control. Stress increased HR and state anxiety whereas tear SIgA concentration decreased 44% post-stress vs.

CONTROL

Higher peak HR values during stress uniquely explained 21% of the variance in tear SIgA reactivity to stress (p < 0.01); high HR reactors displayed greater decreases in tear SIgA concentration. We conclude that physiological arousal increases immune reactivity to acute stress and highlight tear SIgA as a minimally-invasive, physiologically relevant biomarker of immune reactivity.

Surgeons' and surgical trainees' acute stress in real operations or simulation: A systematic review

BACKGROUND AND PURPOSE

Acute stress in surgery is ubiquitous and has an immediate impact on surgical performance and patient safety. Surgeons react with several coping strategies; however, they recognise the necessity of formal stress management training. Thus, stress assessment is a direct need. Surgical simulation is a validated standardised training milieu designed to replicate real-life situations. It replicates stress, prevents biases, and provides objective metrics. The complexity of stress mechanisms makes stress measurement difficult to quantify and interpret. This systematic review aims to identify studies that have used acute stress estimation measurements in surgeons or surgical trainees during real operations or surgical simulation, and to collectively present the rationale of these tools, with special emphasis in salivary markers.

METHODS

A search strategy was implemented to retrieve relevant articles from MEDLINE and SCOPUS databases. The 738 articles retrieved were reviewed for further evaluation according to the predetermined inclusion/exclusion criteria.

RESULTS

Thirty-three studies were included in this systematic review. The methods for acute stress assessment varied greatly among studies with the non-invasive techniques being the most commonly used. Subjective and objective tests for surgeons' acute stress assessment are being presented.

CONCLUSION

There is a broad spectrum of acute mental stress assessment tools in the surgical field and simulation and salivary biomarkers have recently gained popularity. There is a need to maintain a consistent methodology in future research, towards a deeper understanding of acute stress in the surgical field.

Sex differences in salivary cortisol reactivity to the Trier Social Stress Test (TSST): A meta-analysis

Some, but not all studies using the Trier Social Stress Test (TSST) have demonstrated evidence in support of sex differences in salivary cortisol. The aim of the current meta-analysis is to examine sex differences in salivary cortisol following exposure to the TSST. We further explored the effects of modifications to the TSST protocol and procedural variations as potential moderators. We searched articles published from January, 1993 to February, 2016 in MedLine, PsychINFO, and ProQuest Theses and Dissertations. This meta-analysis is based on 34 studies, with a total sample size of 1350 individuals (640 women and 710 men). Using a random effects model, we found significant heterogeneity in salivary cortisol output across sexes, such that men were observed to have higher cortisol values at peak and recovery following the TSST compared to women. Modifications to the sampling trajectory of cortisol (i.e., duration of acclimation, peak sampling time, and duration of recovery) significantly moderated the heterogeneity across both sexes. Further, there are observed sex differences at various time points of the reactive cortisol following the TSST. Lastly, current results suggest that these sex differences can be, at least in part, attributed to variations in methodological considerations across studies. Future research could advance this line of inquiry by using other methods of analyses (e.g., area under the curve; AUC), in order to better understand the effects of methodological variations and their implications for research design.

Investigation of Sex Differences In sIgA Response to the Trier Social Stress Test

Acute stressors can activate the immune system. While many immune system diseases disproportionally affect women, sex differences in adaptive immune response to acute, psychosocial stressors remain to be investigated. The present study tested the hypothesis that female participants experience increased immune response to acute psychosocial stress relative to male participants. Salivary secretory immunoglobulin A (sIgA) was assessed before and after the Trier Social Stress Test (TSST) and at two time points during a recovery period in healthy male (n = 25) and female (n = 24) participants. Exposure to the TSST resulted in significantly increased sIgA that returned to baseline during a subsequent recovery period. Baseline sIgA was higher among women, however, no differences between men and women in response to or recovery from the stressor were observed in the present study. This research describes an initial investigation of sex differences in immune response to acute psychosocial stressors and demonstrates similarity in sIgA response among male and female participants. Copyright © 2016 John Wiley & Sons, Ltd.

Oral Administration of Lactobacillus plantarum 299v Reduces Cortisol Levels in Human Saliva during Examination Induced Stress: A Randomized, Double-Blind Controlled Trial

Objective. To clarify the effect of Lactobacillus plantarum 299v on the salivary cortisol and salivary IgA levels in young adults under examination stress. Design. Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification of L. plantarum 299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing. Results. A significant difference in cortisol levels was found between the treatment group and the placebo group (P < 0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group (P < 0.001). No significant changes were found for salivary IgA. Conclusion. A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study is NCT02974894, and the study is registered at ClinicalTrials.gov.

Elevated salivary IgA, decreased anxiety, and an altered oral microbiota are associated with active participation on an undergraduate athletic team

BACKGROUND

Previous reports indicate that regular, but not excessive, exercise can moderate the response to anxiety and alter the immune response, therefore we hypothesized that college student athletes who were actively participating on an NCAA Division III athletics team ("in-season") would have lower levels of anxiety and higher salivary IgA levels than similar college athletes who were in their "off-season". NCAA Division III athletes participate in athletics at a level of intensity that is more moderate compared to other NCAA divisions. Alterations in the microbiome have been associated with alterations in psychosocial well-being and with exercise. Therefore, we also proposed that the oral microbiota would be different in "in-season" versus "off-season" athletes.

METHOD

In this pilot study, nineteen female students participating on a NCAA Division III athletic team (hockey="in-season"; soccer="off-season") were compared for level of fitness (modified Balke test of VO₂ max), salivary IgA levels by immunoassay, anxiety (using a GAD-7 survey), salivary cortisol levels by immunoassay, and numbers of culturable bacteria by growth of CFU/ml on blood agar, mitis salivarius agar and Staphylococcus 110 agar.

RESULTS

The proportion of subjects reporting "severe anxiety" on an anxiety scale (GAD-7) were significantly greater in the "off-season" group compared to the "in-season" group (p=0.047, Chi-squared test). "In-season" athletes had significantly higher salivary IgA/total protein levels than "off-season" athletes (one-sided Student's t-test; p=0.03). Cortisol levels were not significantly different in the two groups. The total culturable bacteria counts were higher among "in-season" athletes (p=0.0455, Wilcoxon Rank Sum test), as measured by CFUs on blood agar plates, an estimate of total culturable bacteria, including pathogenic and non-pathogenic bacteria. In contrast, there was a decrease in the growth of bacteria from the oral cavity of the "in-season" athletes, when the growth of bacteria on mitis salivarius agar (primarily oral streptococcus) was measured (p=0.0006, Wilcoxon Rank Sum test). There was a negative correlation (Spearman Rank correlation coefficient=-0.651, p=0.0018 one-sided) between high IgA levels and the growth of bacteria on mitis salivarius agar in the combined group of "in-season" and "off-season" athletes, suggesting a protective response of high IgA levels to the typical oral pathogenic bacteria. Anxiety levels (GAD-7) in the "in-season" group were positively correlated with growth of oral bacteria on blood agar (Spearman Rank correlation coefficient of 0.622 for "in-season", p value=0.033 one-sided) and mitis salivarius agar (Spearman Rank correlation coefficient=0.671 for "in-season, p value=0.021 one-sided), and negatively correlated in "off-season" athletes on blood agar (-0.689 for "off-season", p value=0.028 one-sided), supporting the hypothesis that the microbiota are distinct in "in-season" and "off-season" athletes and may be associated with anxiety levels.

CONCLUSION

These findings are supportive of the hypothesis that participation in college level athletics has a positive effect on student-athlete health, specifically enhanced protective oral immunity, reduced anxiety, and alterations in oral microbial populations.

The Trier Social Stress Test: Principles and practice

Researchers interested in the neurobiology of the acute stress response in humans require a valid and reliable acute stressor that can be used under experimental conditions. The Trier Social Stress Test (TSST) provides such a testing platform. It induces stress by requiring participants to make an interview-style presentation, followed by a surprise mental arithmetic test, in front of an interview panel who do not provide feedback or encouragement. In this review, we outline the methodology of the TSST, and discuss key findings under conditions of health and stress-related disorder. The TSST has unveiled differences in males and females, as well as different age groups, in their neurobiological response to acute stress. The TSST has also deepened our understanding of how genotype may moderate the cognitive neurobiology of acute stress, and exciting new inroads have been made in understanding epigenetic contributions to the biological regulation of the acute stress response using the TSST. A number of innovative adaptations have been developed which allow for the TSST to be used in group settings, with children, in combination with brain imaging, and with virtual committees. Future applications may incorporate the emerging links between the gut microbiome and the stress response. Future research should also maximise use of behavioural data generated by the TSST. Alternative acute stress paradigms may have utility over the TSST in certain situations, such as those that require repeat testing. Nonetheless, we expect that the TSST remains the gold standard for examining the cognitive neurobiology of acute stress in humans.

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The TSST is the human experimental gold standard for evaluating the neurobiology of acute stress.

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The HPA axis response to the TSST is higher in males and lower in older adults.

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Genotype and epigenetic factors moderate the neurobiological response to the TSST.

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Multiple adaptations of the TSST are available for different testing contexts.

Coordination of cortisol response to social evaluative threat with autonomic and inflammatory responses is moderated by stress appraisals and affect

Recent approaches to stress regulation have emphasized coordination among multiple biological systems. This study builds on evidence that hypothalamic-pituitary-adrenal (HPA) axis activity should be considered in coordination with other stress-sensitive biological systems to characterize healthy responses. Healthy African-Americans (n=115) completed the Trier Social Stress Test, and biological responses were assessed through salivary cortisol, dehydroepiandrosterone-sulfate (DHEA-S), alpha amylase (sAA), and C-reactive protein (sCRP). Multilevel modeling demonstrated that cortisol responses typically aligned with changes in DHEA-S, sAA, and sCRP across the session. At the same time, the degree of cortisol coordination with sAA and sCRP varied by participants' subjective stress following the task; participants with higher secondary stress appraisals showed greater cortisol-sAA alignment, whereas those experiencing more negative affect showed greater cortisol-sCRP alignment. Results highlight the importance of a multisystem approach to stress and suggest that positive HPA axis coordination with the autonomic response, but not with the immune/inflammatory response, may be adaptive.

Relationship between salivary stress biomarker levels and cigarette smoking in healthy young adults: an exploratory analysis

Background

This study investigated the relationships among salivary stress biomarkers, cigarette smoking, and mood states.

Methods

The study population comprised 49 healthy sixth-year dental students at Fukuoka Dental College (39 men, 10 women; age, 23–31 years). Lifetime exposure to smoking was calculated using the Brinkman index (BI). Resting saliva samples were collected, and concentrations of cortisol, secretory immunoglobulin A (SIgA), interleukin (IL)-1β, interleukin-6, and tumor necrosis factor (TNF)-α were determined. Mood states (tension-anxiety, depression-dejection, anger-hostility, fatigue, confusion, and vigor) over the previous week were assessed using the Profile of Mood States - Brief Japanese Version.

Results

Salivary IL-1β levels were significantly higher in smokers than non-smokers (P = 0.044), regardless of the BI or mood state. A significant positive correlation was evident between the TNF-α level and the BI (P = 0.036), and the SIgA level was positively correlated with the BI (P = 0.067) but did not reach statistical significance. In terms of mood states, higher fatigue scores and lower vigor scores were observed in smokers. The TNF-α level and vigor score were negatively correlated (r = –0.229, P = 0.135), but the correlation did not reach statistical significance. However, the SIgA level and fatigue score were significantly positively correlated (r = 0.410, P = 0.005).

Conclusions

The TNF-α and SIgA levels were both positively correlated with the BI. Furthermore, the TNF-α level was negatively correlated with the vigor score, whereas the SIgA level was positively correlated with the fatigue score. Thus, salivary levels of TNF-α and SIgA may be used as biomarkers of mood states in healthy young smokers.

Secretory IgA reactivity to social threat in youth: Relations with HPA, ANS, and behavior

Although the role of immune marker secretory immunoglobulin A (SIgA) in stress-related health outcomes is gaining recognition, SIgA responsiveness to acute stress has rarely been assessed in adults, and not at all in children. This study was designed to clarify developmental origins of differential immune function-related health risks by investigating youth SIgA responses to psychosocial stressors, including both normative responses and variability related to behavioral problems. Children and adolescents from a larger study (n=82) gave 6 saliva samples during a laboratory session in which they were exposed to a series of performance or interpersonal stressors. Samples were assayed for SIgA, as well as cortisol (representing hypothalamic-pituitary-adrenal axis activity) and alpha-amylase (sAA; representing autonomic nervous system activity). Behavioral problems were assessed with parent-report measures of youth internalizing and externalizing. Youth SIgA trajectories followed a normative pattern of reactivity and recovery around the stressors; however, these responses were blunted in youth with higher externalizing scores. SIgA showed differential associations with cortisol and sAA, and with positive and negative affect; whereas overall levels of SIgA related to cortisol output and positive affect, changes in SIgA over time synchronized with changes in sAA and negative affect. In contrast to SIgA, neither cortisol nor sAA related significantly to behavioral problems. Implications for the role of SIgA during psychosocial stress in the development of immune function-related health risks are discussed.

Salivary markers of inflammation in response to acute stress

There is burgeoning interest in the ability to detect inflammatory markers in response to stress within naturally occurring social contexts and/or across multiple time points per day within individuals. Salivary collection is a less invasive process than current methods of blood collection and enables intensive naturalistic methodologies, such as those involving extensive repeated measures per day over time. Yet the reliability and validity of saliva-based to blood-based inflammatory biomarkers in response to stress remains unclear. We review and synthesize the published studies that have examined salivary markers of inflammation following exposure to an acute laboratory stressor. Results from each study are reviewed by analyte (IL-1β, TNF-α, IL-6, IL-2, IL-4, IL-10, IL-12, CRP) and stress type (social-cognitive and exercise-physical), after which methodological issues and limitations are addressed. Although the literature is limited, several inflammatory markers (including IL-1β, TNF-α, and IL-6) have been reliably determined from saliva and have increased significantly in response to stress across multiple studies, with effect sizes ranging from very small to very large. Although CRP from saliva has been associated with CRP in circulating blood more consistently than other biomarkers have been associated with their counterparts in blood, evidence demonstrating it reliably responds to acute stress is absent. Although the current literature is presently too limited to allow broad assertion that inflammatory biomarkers determined from saliva are valuable for examining acute stress responses, this review suggests that specific targets may be valid and highlights specific areas of need for future research.

The relationship between maternal postpartum psychological state and breast milk secretory immunoglobulin A level

BACKGROUND

Maternal psychological state may influence the passive transfer of immune factors (e.g., immunoglobulin) via the mother's breast milk.

OBJECTIVE

The aim of this study was to determine whether a correlation exists between mothers' postpartum psychological state and their breast milk secretory immunoglobulin A (SIgA) levels.

STUDY DESIGN

Eighty-one mothers who delivered at an urban general hospital were included in our analysis. Two weeks after delivery, we measured their breast milk SIgA levels and simultaneously documented their psychological state using the Profile of Mood States (POMS), General Health Questionnaire (GHQ), and State-Trait Anxiety Inventory (STAI) scales.

RESULTS

Breast milk SIgA levels were negatively correlated with negative POMS states (tension-anxiety, depression-dejection, anger-hostility, fatigue, and confusion). A negative correlation was also observed between SIgA levels and GHQ mental health (r = -.625, P = .000), and a similar negative correlation was observed with STAI trait and state anxieties. However, no correlation existed between breast milk SIgA levels and the positive POMS state (vigor).

CONCLUSIONS

These results indicate that the maternal psychological state may affect the immune properties of breast milk.

Global stress response during a social stress test: impact of alexithymia and its subfactors

OBJECTIVES

Alexithymia is a personality trait characterized by difficulties in identifying, describing and communicating one's own emotions. Recent studies have associated specific effects of this trait and its subfactors with hypothalamo-pituitary-adrenal (HPA) axis markers during stress. The aim of this study was to analyze the association between alexithymia and its subfactors with HPA and sympatho-adrenal medullar (SAM) activity. Stress was induced experimentally using a public-speaking paradigm. Salivary cortisol, alpha-amylase (AA), chromogranin A (CgA) and heart rate (HR) were collected during the defined periods of baseline, stress, and recovery in 19 males and 24 female healthy university students.

RESULTS

Subjects reacted to the stressor with a significant cortisol and SAM response. Subjects scoring high on alexithymia reacted significantly more intensely than low scorers in basal anticipatory as well as peak cortisol and area under the curve. Regression analyses revealed that the increased HPA activity was related to only one alexithymia subfactor, the difficulty in differentiating feelings and distinguishing them from bodily sensations and emotion arousal.

CONCLUSION

Alexithymia and its subfactors were specifically related to cortisol responses. This research should be replicated with more subjects and should take into account more parameters reflecting sympathetic and/or parasympathetic activation, as well as HPA axis. Factors such as coping strategies and the perception of the situation as a challenge have also to be explored.

A sustained hypothalamic-pituitary-adrenal axis response to acute psychosocial stress in irritable bowel syndrome

BACKGROUND

Despite stress being considered a key factor in the pathophysiology of the functional gastrointestinal (GI) disorder irritable bowel syndrome (IBS), there is a paucity of information regarding the ability of IBS patients to respond to acute experimental stress. Insights into the stress response in IBS could open the way to novel therapeutic interventions. To this end, we assessed the response of a range of physiological and psychological parameters to the Trier Social Stress Test (TSST) in IBS.

METHOD

Thirteen female patients with IBS and 15 healthy female age-matched control participants underwent a single exposure to the TSST. Salivary cortisol, salivary C-reactive protein (CRP), skin conductance level (SCL), GI symptoms, mood and self-reported stress were measured pre- and post-exposure to the TSST.

RESULTS

The hypothalamic-pituitary-adrenal (HPA) axis response to the TSST was sustained in IBS, as shown by a greater total cortisol output throughout (p = 0.035) and higher cortisol levels measured by an area under the curve with respect to ground (AUCG) analysis (p = 0.044). In IBS patients, GI symptoms increased significantly during the recovery period following exposure to the TSST (p = 0.045). Salivary CRP and SCL activity showed significant changes in relation to stress but with no differential effect between experimental groups.

CONCLUSIONS

Patients with IBS exhibit sustained HPA axis activity, and an increase in problematic GI symptoms in response to acute experimental psychosocial stress. These data pave the way for future interventional studies aimed at identifying novel therapeutic approaches to modulate the HPA axis and GI symptom response to acute psychosocial stress in IBS.

Acute and chronic stress increase salivary cortisol: a study in the real-life setting of a national examination undertaken by medical graduates

Spanish medical graduates who apply for a medical specialty training position (MIR) must take an examination that will shape their future personal and professional lives. Preparation for the test represents an important stressor that persists for several months. The aim of this study was to elucidate the stress pattern of this group and evaluate possible changes in the circadian rhythm of cortisol release in medical graduates preparing for this test. A repeated-measures longitudinal study was performed, measuring the salivary cortisol concentrations in 36 medical graduates (13 males and 23 females; mean age of 24.2 years) on five sampling days. Five cortisol samples were collected from 07:00 to 21:00 h in order to monitor changes in the circadian rhythm. On all sampling days (except on the day of the official examination), anxiety and psychological stress were evaluated with the Spanish versions of the State-Trait Anxiety Inventory (STAI) and the Perceived Stress Scale (PSS). During the study period, participants showed higher levels of anxiety than the Spanish reference population as well as a progressive increase in self-perceived stress. A significant increase in salivary cortisol concentration was observed in both chronic (study and examination preparation) and acute (examinations) situations. Our results suggest that the cortisol awakening response (CAR) may be a good indicator of anticipatory stress but is unaffected by long-term examination preparation. Comparison of results between the official examination day and the mock examination days yielded evidence that learning may modulate the behavior of the hypothalamic-pituitary-adrenal axis.

Risk Patterns Among College Youth

Purpose. This study identified underlying subgroups among college students in terms of lifestyle characteristics and health risk behaviors and then investigated how demographic factors were associated with the underlying risk patterns to bolster health promotion efforts and interventions. Method. College students ( N = 996) enrolled at Indiana University during 2009-2010 participated in a multidimensional online survey. Latent class analysis was used to identify underlying risk patterns based on seven lifestyle and health behaviors, including frequent alcohol use, binge drinking, smoking, low physical activity, low vegetable intake, low fruit intake, and poor sleep. Results. Four distinct risk behavior patterns were identified for both males and females including a “healthy” class, “low substance use but poor other health behaviors” class, “high substance use” (males)/“high alcohol use” (females) class, and a risk class characterized by elevated probability of all seven indicators. The highest risk class included 34% of the males and 22% of the females; they tended to be older or in more advanced undergraduate classes. Among males, compared with the “healthy” class, the “high substance use” class was more likely to contain non-Hispanic White students and students in advanced classes. Among females, the “low substance use but poor other health behaviors” class was associated with racial/ethnic minority status and lower levels of parental education. Conclusions. Our data suggest that risky health behaviors may tend to cluster in some students and that health promotion techniques might effectively be targeted to identifiable student subgroups.

Biological and psychological markers of stress in humans: focus on the Trier Social Stress Test

Validated biological and psychological markers of acute stress in humans are an important tool in translational research. The Trier Social Stress Test (TSST), involving public interview and mental arithmetic performance, is among the most popular methods of inducing acute stress in experimental settings, and reliably increases hypothalamic-pituitary-adrenal axis activation. However, although much research has focused on HPA axis activity, the TSST also affects the sympathetic-adrenal-medullary system, the immune system, cardiovascular outputs, gastric function and cognition. We critically assess the utility of different biological and psychological markers, with guidance for future research, and discuss factors which can moderate TSST effects. We outline the effects of the TSST in stress-related disorders, and if these responses can be abrogated by pharmacological and psychological treatments. Modified TSST protocols are discussed, and the TSST is compared to alternative methods of inducing acute stress. Our analysis suggests that multiple readouts are necessary to derive maximum information; this strategy will enhance our understanding of the psychobiology of stress and provide the means to assess novel therapeutic agents.