Biological Stress Markers Research Articles

Plasma GSH levels and Alzheimer's disease. A prospective approach.: Results from the HELIAD study

BackgroundPotential links between oxidative stress and the pathophysiology of Alzheimer's disease (AD) have been reported in the existing literature. Biological markers of oxidative stress, such as the reduced form of glutathione (GSH), may have a potential role as predictive biomarkers for AD development. The aim of the present study was to explore the longitudinal associations between plasma GSH and the risk of developing AD or cognitive decline, in a sample of community-dwelling, non-demented older adults. MethodsParticipants from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) were included in the present prospective study. The sample used in the analyses consisted of 391 non-demented individuals over the age of 64 (mean age = 73.85 years; SD = 5.06), with available baseline GSH measurements and longitudinal follow-up. Plasma GSH was treated both as a continuous variable and as tertiles in our analyses. Cox proportional hazards models were used to evaluate the hazard ratio (HR) for AD incidence as a function of baseline plasma GSH. Generalized estimating equations (GEE) models were deployed to explore the associations between baseline plasma GSH and the rate of change of performance scores on individual cognitive domains over time. Models were adjusted for age, years of education and sex. Supplementary exploratory models were also adjusted for mild cognitive impairment (MCI) at baseline, risk for malnutrition, physical activity and adherence to the Mediterranean dietary pattern. ResultsA total of 24 incident AD cases occurred during a mean (SD) of 2.99 (0.92) years of follow-up. Individuals in the highest GSH tertile group (highest baseline plasma GSH values) had a 70.1% lower risk for development of AD, compared to those in the lowest one [HR = 0.299 (0.093–0.959); p = 0.042], and also demonstrated a slower rate of decline of their executive functioning over time (5.2% of a standard deviation less decline in the executive composite score for each additional year of follow-up; p = 0.028). The test for trend was also significant suggesting a potential dose-response relationship. ConclusionIn the present study, higher baseline plasma GSH levels were associated with a decreased risk of developing AD and with a better preservation of executive functioning longitudinally.

Evidence for Better Lives Study: a comparative birth-cohort study on child exposure to violence and other adversities in eight low- and middle-income countries - foundational research (study protocol)

IntroductionViolence against children is a health, human rights and social problem affecting approximately half of the world’s children. Its effects begin at prenatal stages with long-lasting impacts on later health...

Ibudilast for alcohol use disorder: study protocol for a phase II randomized clinical trial

BackgroundAlcohol use disorder (AUD) is a chronic and relapsing condition for which current pharmacological treatments are only modestly effective. The development of efficacious medications for AUD remains a high research priority with recent emphasis on identifying novel molecular targets for AUD treatment and to efficiently screen new compounds aimed at those targets. Ibudilast, a phosphodiesterase inhibitor, has been advanced as a novel addiction pharmacotherapy that targets neurotrophin signaling and neuroimmune function.MethodsThis study will conduct a 12-week, double-blind, placebo controlled randomized clinical trial of ibudilast (50 mg BID) for AUD treatment. We will randomize 132 treatment-seeking men and women with current AUD. We will collect a number of alcohol consumption outcomes. Primary among these is percent heavy drinking days (PHDD); secondary drinking outcomes include drinks per day, drinks per drinking day, percent days abstinent, percent subjects with no heavy drinking days, and percent subjects abstinent, as well as measures of alcohol craving and negative mood. Additionally, participants will have the option to opt-in to a neuroimaging session in which we examine the effects of ibudilast on neural activation to psychosocial stress and alcohol cues. Finally, we will also collect plasma levels of proinflammatory markers, as well as subjective and biological (salivary cortisol) markers of stress response.DiscussionThis study will further develop ibudilast, a safe and promising novel compound with strong preclinical and clinical safety data for AUD, and will probe biological mechanisms underlying the effects of Ibudilast on stress, neuroinflammation, and alcohol cue-reactivity and craving. If ibudilast proves superior to placebo in this study, it will set the stage for a confirmatory multi-site trial leading to FDA approval of a novel AUD treatment.Trial registrationClinicalTrials.gov NCT03594435 “Ibudilast for the Treatment of Alcohol Use Disorder”. Registered on 20 July 2018.

Acute and Chronic Stress in Daily Police Service: A Three-Week N-of-1 Study

On duty, police officers are exposed to a variety of acute, threatening stress situations and organizational demands. In line with the allostatic load model, the resulting acute and chronic stress might have tremendous consequences for police officers’ work performance and psychological and physical health. To date, limited research has been conducted into the underlying biological, dynamic mechanisms of stress in police service. Therefore, this ecological momentary assessment study examined the associations of stress, mood and biological stress markers of a 28-year-old male police officer in a N-of-1 study over three weeks (90 data points). Four times a day (directly after waking up, 30 minutes later, 6 hours later, before going to bed), he answered questions about the perceived stress and mood using a smartphone application. With each data entry, he collected saliva samples for the later assessment of salivary cortisol (sCort) and alpha-amylase (sAA). In addition, data was collected after six police incidents during duty. sCort and sAA were not related to perceived stress in daily life and did not increase in police incidents. Regarding mood measures, deterioration of calmness, but not valence and energy was associated with perceived stress. The results suggest continued police service to constitute a major chronic stressor resulting in an inability to mount a proper response to further acute stress. As an indicator of allostatic load, psychological and biological hyporesponsivity in moments of stress may have negative consequences for police officers’ health and behavior in critical situations that require optimal performance. Prospectively, this research design may also become relevant when evaluating the efficacy of individualized stress management interventions in police training.

A Systematic Review of the Association between Poverty and Biomarkers of Toxic Stress

ABSTRACT Purpose: Toxic stress has been identified as a key mechanism by which poverty impacts health and empirical evidence on the relationship between poverty and biological markers of toxic stress is accumulating. This study synthesizes the empirical evidence of the relationship between poverty and biomarkers of toxic stress. Method: We conduct a systematic literature review using PRISMA guidelines to assess the relationship between poverty and toxic stress. A total of 56 articles are included in the review assessing 63 poverty and toxic stress relationships. Results: Seventeen of 30 reviewed relationships showed a statistically significant relationship between our measures of poverty and biomarker outcomes. Additionally, 12 of the remaining 13 studies demonstrated partially statistically significant relationship between our poverty measures and biomarker outcomes. Conclusion: Findings demonstrate evidence of the relationship between poverty and toxic stress. Consistently, poverty was related to biological stress and neighborhood poverty was related to physical stress outcomes.

On the Physiology of Investment Biases: The Role of Cortisol and Testosterone

The underlying physiological mechanisms of biases are not well understood. As such, we examine the impact of testosterone and cortisol levels on several commonplace investment biases using realistic trading simulations. Cortisol, the biological marker of stress, is positively related to the disposition effect and portfolio turnover, which is consistent with the relation between judgment errors and stress in social settings. Testosterone, the male hormone, is also positively related to portfolio turnover, which is consistent with androgen-driven behaviors. Overall, the results show that the endocrine system plays a significant role during financial decision-making, which has important consequences for the financial industry.

The impact of an ultra-trail on the dynamic of cardiac, inflammatory, renal and oxidative stress biological markers correlated with electrocardiogram and echocardiogram

The aim of this study was to describe the effects of a 64.2 km ultra-trail on the biomarkers of muscle damage, inflammation and oxidative stress, and compare the results observed with an ECG and an echocardiogram, both performed before and after the race. Thirty-three ultra-trail volunteers (45.8 ± 8.7 years old) were enrolled in our study. Three blood tests were drawn from each runner, one just before (TPRE), one just after (TPOST) and the last 3 h after the end of the race (TPOST3h). All the markers increased. The maximum concentrations observed were at TPOST3h and were significant (p < 0.001) for creatine kinase, creatine kinase isoform MB, high-sensitivity C-reactive protein, uric acid and for the ratio of reduced glutathione to oxidised glutathione. However, in the case of myoglobin, high-sensitive troponin T, N-terminal pro-brain natriuretic peptide, oxidised glutathione, myeloperoxidase, cystatin C and creatinine, the most significant increases were at TPOST (p < 0.001). Modifications were observed in the medical imaging using echocardiography such as reduction of left ventricule end-sytolic and diastolic volumes and left ventricular global longitudinal strain. ECG showed electrical criteria for left ventricular hypertrophy and incomplete right bundle branch block after the race. Endurance races cause significant physiological stress to the body that can be measured by the increase of different biomarkers. From a laboratory perspective, it is important to take into account the possible exercise performed previous to the testing to avoid a misinterpretation of the results. From a training perspective, due to these increases in biomarkers, it is recommended that runners wait at least 72 h after an ultra-trail before subsequent training. In addition a transient impairment of ventricular function due to dehydration were observed.

Hair Cortisol Concentrations as a Biological Marker of Maternal Prenatal Stress: A Systematic Review.

Recently, biological markers of maternal prenatal stress, hair cortisol, along with saliva, blood, and urine cortisol, have received attention. However, it is necessary to validate measuring hair cortisol concentrations (HCC) as a biomarker of perceived stress among healthy and high-risk pregnant women. This study aimed to confirm the correlation between HCC and the perceived stress of pregnant women over 18 years of age. In this systematic review, we used various search engines to extract relevant articles using specific keywords related to pregnancy, hair cortisol, and psychological stress. Four out of 3639 studies met the inclusion criteria. We conducted a quality assessment with the help of three independent reviewers using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. The correlation between HCC and perceived stress was confirmed in one study. There was only one study on hair washing, shampoo, conditioner, and hair structure that could affect hair samples. In four studies, hair samples differed in length, methods of storage, and laboratory analysis. The review was limited to confirming the relationship between HCC and perceived stress in pregnant women based on the current evidence. Studies on hair cortisol need regulated and standardized methods for collection, storage, and analysis of hair samples.

Biological markers of oxidative stress in exhaled air

Biological markers of oxidative stress in exhaled air

2,4-D exposure and urinary markers of oxidative DNA damage and lipid peroxidation: a longitudinal study

Objective2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide that is commonly used commercially, agriculturally and residentially worldwide. There is concern about its potential for carcinogenicity based on studies in laboratory animals demonstrating...

On the Physiology of Investment Biases: The Role of Cortisol and Testosterone

The underlying physiological mechanisms of biases are not well understood. As such, we examine the impact of testosterone and cortisol levels on several commonplace investment biases using realistic trading simulations. Cortisol, the biological marker of stress, is positively related to the disposition effect and portfolio turnover, which is consistent with the relation between judgment errors and stress in social settings. Testosterone, the male hormone, is also positively related to portfolio turnover, which is consistent with androgen-driven behaviors. Overall, the results show that the endocrine system plays a significant role during financial decision-making, that has important consequences for the financial industry.

The association between perceived stress and diet quality in women of childbearing age: A systematic review

AbstractPoor diet quality is a major cause of maternal obesity and associated with adverse metabolic effects for mother and offspring. Psychological stress can increase intake of unhealthy dietary choices (e.g. highly palatable, energy dense diet), but no study has investigated the association between stress and diet quality in women of childbearing age.This systematic review of the association between psychological stress and diet quality used the PEO (Population, Exposure, and Outcome) model.Medline, CINAHL, Scopus, Cochrane Library, Web of Science, and Sciencedirect were searched (October 2018 - January 2019). From 139,552 hits, 471 papers were screened, but only 8 studies met our inclusion criteria: English language, stress (exposure) measured in combination with diet quality (outcome), healthy women (18–49 years of age (population). Data extraction was determined by the PEO. Quality assessment used CASP tool for Cohort studies.The review included eight studies from USA (n = 6), Egypt (n = 1), and Iran (n = 1). The six cross-sectional and two longitudinal studies were published between 2011 and 2017 and had a total of 3,982 participants. Studies were heterogeneous in methods: three used food frequency questionnaires to assess dietary intake while the others used 24-hour dietary recalls. Diet quality was measured using different indices: Alternate Healthy Eating Index (n = 2), Healthy Eating Index (n = 2), Dietary Approach to Stop Hypertension (DASH) Diet Index (n = 2), Dietary Quality Index- Pregnancy (n = 2), and Dietary Guideline Adherence Index (n = 1). Only one study used three diet quality indices. No study explored dietary patterns using factor analysis and other statistical techniques. Most studies used the perceived stress scale to measure stress; however, there were differences regarding the use of this scale to form a continuous or categorical variable (with varying cut-off scores) perceived stress, whereas no study reported biological response to stress. Outcomes also varied in direction of association; no association (n = 4), negative association (n = 3), mixed results (n = 1).This review is the first to systematically examine association between stress and diet quality in women of childbearing age; there was heterogeneity in measures of diet quality and study designs. Future studies that explore diet quality/patterns should include both diet indices and factor analysis and additionally measure biological markers of both dietary intake and stress.

Show Me the Meaning of Being Lonely (and Its Effects on Seizure Burden and Comorbidities).

Effects of Single Cage Housing on Stress, Cognitive, and Seizure Parameters in the Rat and Mouse Pilocarpine Models of Epilepsy Manouze H, Ghestem A, Poillerat V, Bennis M, Ba-M’hamed S, Benoliel JJ, Becker C, Bernard C. eNeuro. 2019;6(4). doi:10.1523/ENEURO.0179-18.2019.Many experimental approaches require housing rodents in individual cages, including in epilepsy research. However, rats and mice are social animals; and individual housing constitutes a stressful situation. The goal of the present study was to determine the effects of individual housing as compared to conditions maintaining social contact on stress markers and epilepsy. Control male mice socially housed during pretest and then transferred to individual cages for 6 weeks displayed anhedonia, increased anxiety, and biological markers of stress as compared to pretest values or mice kept socially housed during 6 weeks. Pilocarpine (pilo)-treated mice housed together showed increased levels of anhedonia, anxiety, and stress markers as well as decreased cognitive performance as compared to the control group. The differences were more significant in pilo-treated mice housed individually. Anxiety correlated linearly with cognitive performance and stress markers independently of the experimental conditions. In the male rat pilo model, seizures were 16 times more frequent in singly housed animals as compared to animals kept in pairs. Daily interactions with an experimenter in otherwise singly housed animals was sufficient to produce results identical to those found in animals kept in pairs. We propose that social isolation produces a severe phenotype in terms of stress and seizure frequency as compared to animals maintaining social contact (at least in these 2 models), a factor that needs to be taken into account for data interpretation, in particular for preclinical studies.

Exploring Associations Between a Biological Marker of Chronic Stress and Reported Depression and Anxiety in People With Aphasia.

Purpose Living with the communication impairment of aphasia can be stressful. Chronic stress, depression, and anxiety are intimately linked, may be more pervasive in people with poststroke aphasia than the general population, and may influence cognitive function and treatment outcomes. In this project, we explored the psychological constructs of depression and anxiety and their associations with a biomarker measure of chronic stress in people with aphasia. Method Fifty-seven participants with aphasia completed measures of depression and anxiety and provided a hair sample from which to extract the stress hormone cortisol. Pearson product-moment correlational analyses were used to identify associations between depression, anxiety, and long-term level of cortisol via hair sample. Results While cortisol level was not associated with depression and anxiety across this sample of people with aphasia, a post hoc analysis showed a significant, positive correlation between a subset of participants with moderate and higher levels of depression and elevated cortisol level. Conclusions Chronic stress, depression, and anxiety have been little explored in people with aphasia to date, yet they are associated with future health consequences and impaired cognitive function, motivating further research as well as consideration of these factors in aphasia rehabilitation.

Effects of an 8-Week Body Scan Intervention on Individually Perceived Psychological Stress and Related Steroid Hormones in Hair

An increased psychosocial stress level is a continuously growing public health problem. While previous studies investigated the stress-related effects of mindfulness-based stress reduction (MBSR), it is still largely unknown, whether chronic stress decreases after an 8-week training of a body scan meditation. This study aimed at closing this gap by examining the effects of a body scan on chronic stress markers. In this study, 47 healthy students were randomly assigned to an intervention group (n = 24) and a control group (n = 23). Participants in the intervention group used a 20-min long audio recording of a guided body scan. The control group listened to an audio book for the same amount of time. On the biological level, stress was assessed by selected stress hormones (cortisol, dehydroepiandrosterone (DHEA), and its ratio) from hair samples. Psychological stress load was measured by the Screening of the Trier Inventory of Chronic Stress. The body scan group showed a decreased level of cortisol, and cortisol/DHEA ratio, as well as an increased level of DHEA compared with the audio book group. Regarding psychological stress, a decreased value was observed in both groups. Additional correlation analyses demonstrate no relationship between biological and psychological chronic stress markers. Overall, data suggest positive effects of an 8-week body scan, especially for biological stress markers. Investigating the effects of this intervention in populations with a high risk for increased levels of stress (e.g., unemployment) would be particularly interesting.

Role of polygenic risk in susceptibility to accelerated pubertal onset following chronic stress exposure.

Previous finding suggests that children growing up under chronic stress tend to experience earlier sexual maturity. The present study aims to examine polygenic risk by experience interaction in predicting pubertal timing, as well as provide insight regarding the relevance of two G × E paradigms. Data were analyzed from a 3-year prospective puberty cohort in Anhui Province, China. Breast Tanner stage and testicular volume (TV) of 997 children were annually assessed. The polygenic risk score (PRS) was computed based on 17 SNPs for early pubertal timing. Hair cortisol concentrations (HCC) were assessed in the first 3 cm hair segment as a biological marker of chronic stress. Comparing with participants under moderate levels of stress as measured by HCC, the puberty-accelerating effects of chronic stress were only observed among girls with moderate (1.7 months earlier, P = 0.007) and low genetic susceptibility (2.2 months earlier, P < 0.001) and among boys with high genetic susceptibility (2.0 months earlier, P = 0.005). Polygenic differences (PRSs) in age at thelarche was most prominent in those with low levels of stress by HCC (9.06, 9.36 and 9.53 years for high, moderate and low PRS, respectively; F = 105.06, P < 0.0001), while polygenic differences in age at TV ≥4 mL was strongest in those under chronic stress (10.91, 11.06 and 11.17 years for high, moderate and low PRS, respectively; F = 100.48, P < 0.0001). Chronic stress predicts earlier age at pubertal onset in a sex-specific and genetic background-dependent manner. The bioecological G × E model for girls and diathesis stress model for boys in pubertal timing warrants further investigation.

Effects of Single Cage Housing on Stress, Cognitive, and Seizure Parameters in the Rat and Mouse Pilocarpine Models of Epilepsy.

Many experimental approaches require housing rodents in individual cages, including in epilepsy research. However, rats and mice are social animals; and individual housing constitutes a stressful situation. The goal of the present study was to determine the effects of individual housing as compared to conditions maintaining social contact on stress markers and epilepsy. Control male mice socially housed during pretest and then transferred to individual cages for six weeks displayed anhedonia, increased anxiety and biological markers of stress as compared to pretest values or mice kept socially housed during six weeks. Pilocarpine (pilo)-treated mice housed together showed increased levels of anhedonia, anxiety and stress markers as well as decreased cognitive performance as compared to the control group. The differences were more significant in pilo-treated mice housed individually. Anxiety correlated linearly with cognitive performance and stress markers independently of the experimental conditions. In the male rat pilo model, seizures were sixteen times more frequent in singly housed animals as compared to animals kept in pairs. Daily interactions with an experimenter in otherwise singly housed animals was sufficient to produce results identical to those found in animals kept in pairs. We propose that social isolation produces a severe phenotype in terms of stress and seizure frequency as compared to animals maintaining social contact (at least in these two models), a factor that needs to be taken into account for data interpretation, in particular for preclinical studies.

The Effect of Prebiotic Consumption on the Gastrointestinal Microbiota of Healthy Adults: A Randomized, Controlled, Crossover Trial (P20-015-19)

ObjectivesChronic stress is recognized as a contributing factor in health conditions such as depression, anxiety, and sleep disturbances. Prebiotic consumption, which changes the gastrointestinal microbiota in a way that benefits host health, is one potential treatment being explored to alleviate these conditions. Accordingly, we aimed to determine the effects of fructooligosaccharide (FOS) and galactooligosaccharide (GOS) consumption on changes in the gastrointestinal (GI) microbiota and biological and behavioral markers of stress among adults. MethodsA randomized, controlled, double-blind, crossover trial was conducted in healthy adults (n = 24) between 25 and 45 years of age. Participants consumed two study beverages in a counter balanced order: 1) 8 oz per day 1% Lactaid (control) and 2) 8 oz of 1% Lactaid with 5 g FOS and 5 g GOS (prebiotic). Each study beverage was consumed daily for 4-weeks with a 2 to 4-week washout between study periods. Fecal samples were collected at the beginning and end of each period. Following fecal DNA extraction, the V4 region of the 16S rRNA gene was amplified. Sequencing was performed on an Illumina HiSeq. Sequence data were analyzed with DADA2 and QIIME 2. Taxonomy was assigned with the GreenGenes 13_8 99% OTU reference database. Statistical analyses were conducted in SAS 9.4 using linear mixed modeling with time, treatment, and the time by treatment interaction as fixed effects and participant and period as random effects. ResultsPrebiotic consumption increased the relative abundance of Bifidobacterium (P = 0.01) compared to the control group. In addition, there was an increase observed in the relative abundance of Erysipelotrichaceae Clostridium (P = 0.04) in the prebiotic group and a decrease in the control group. In contrast, there was a decrease observed in the relative abundance of Prevotella (P = 0.004) in the prebiotic group and an increase in the control group. ConclusionsThese results demonstrate that FOS and GOS induce changes in the GI microbiota of healthy adults. Ongoing analyses include an examination of the relationships between 24-hour urinary free cortisol concentrations, a potential biological marker of stress, and relative abundance of microbes examined in the current study. Funding SourcesUSDA National Institute of Food and Agriculture, Hatch project 1009249.

Evaluation of the Salivary Level of Cortisol in Patients with Oral Lichen Planus: A Meta-Analysis.

Background and objective: Cortisol, as the main human glucocorticoid, is considered to be a biological marker of stress and anxiety. Since it is known that oral lichen planus (OLP) can appear and worsen during stressful events, cortisol levels have been previously studied in OLP patients. The present meta-analysis aims to assess the salivary concentration of cortisol in OLP patients compared to healthy controls. Materials and methods: Web of Science, PubMed, Cochrane Library, and Scopus databases were searched up to October 2018. The RevMan 5.3 software was used with the mean difference (MD) and 95% confidence intervals (CIs). The CMA 2.0 Software was used to evaluate the publication bias, sensitivity analysis, and meta-regression as possible sources of heterogeneity. Results: 10 studies were analyzed and a total of 269 OLP patients and 268 controls were included. The pooled MD of the salivary levels of cortisol in OLP patients compared with controls was 4.27 ng/mL (95% CI: 2.33, 6.21; P < 0.0001), thus, the salivary level of cortisol in OLP patients was significantly higher than in controls. In Indian-based population studies, a significant difference in the salivary cortisol levels in OLP patients compared with controls was detected (MD = 5.62 ng/mL; 95% CI: 2.67, 8.56; P = 0.0002). In addition, a significant difference in the salivary cortisol levels in the OLP patients compared with the controls was obtained in studies performed with enzyme-linked immunosorbent assay (ELISA) method (MD = 5.33 ng/mL; 95% CI: 2.72, 7.93; P < 0.0001). Conclusion: We suggest that supportive psychological treatment together with the conventional therapy could increase patients’ capability to prevent stress, anxiety, and depression.

The effect of acute stress on salivary markers of inflammation: a systematic review protocol

BackgroundThere is an increasing interest in the ability to non-invasively assess biological markers of stress. Measures of inflammation following exposure to acute stress have been assessed in saliva, but a systematic review and meta-analysis of the reliability of changes in response to stress has not been conducted. The proposed review aims to update and extend a prior review of this literature by performing a systematic review and meta-analysis, conducting moderator analyses, summarizing and reviewing best practices, and providing recommendations for future research.Methods and analysisThe adopted search strategy will involve the electronic databases PubMed, PsycINFO, and Embase. We will include the articles identified by a 2015 narrative review on a similar topic, as well as use reference treeing to identify additional potentially relevant articles. Identified articles will be independently screened by title and abstract. The full text of potentially relevant articles will then be retrieved and read for full inclusion criteria. Data will be extracted, and random-effects meta-analyses will be conducted in R for articles determined to meet all inclusion criteria. The primary outcome will be the magnitude of changes in inflammatory biomarkers following acute stress exposure, as indicated by Cohen’s d. Participant psychosocial or demographic (e.g., age, gender/sex, race/ethnicity, salivary flow rate, oral health status, health status) and methodological (e.g., stressor type, sample timing, assay technique, sample collection method, study quality) moderators of this response also will be examined using meta-regression.DiscussionThis systematic review will synthesize the evidence regarding salivary markers of inflammation in response to acute stress. We anticipate variation across studies but hypothesize that salivary markers of inflammation will increase in response to acute stress. The evidence obtained for this study will help guide future research by providing guidelines for the design and measurement of studies assessing salivary inflammation in response to acute stress. Findings will be disseminated with a peer-reviewed manuscript and an international conference presentation.