Stress-induced Cortisol Research Articles

You look stressed: A pilot study on facial action unit activity in the context of psychosocial stress

Quality and quantity of the human stress response are highly individual. Not only are there differences in terms of psychological and physiological stress reactivity, but also with regard to facial muscle stress reactivity. In a first correlative pilot study to decipher the signature of stress as it presents in the physiognomy of a stressed individual, we investigated how stress-induced muscle movement activity in the face is associated with stress marker activation during a standardized laboratory stress test. Female and male participants (N = 62) completed the Trier Social Stress Test and provided multiple measurements of salivary cortisol, subjective experience, heart rate, and high-frequency heart rate variability. In addition, participants were filmed during stress induction to derive the activation of 13 individual muscles or muscle groups, also termed action units (AU). Mean AU intensity and occurrence rates were measured using the opensource software OpenDBM. We found that facial AU activity correlated with different aspects of the psychosocial stress response. Higher stress-induced cortisol release was associated with more frequent upper eyelid raiser (AU05) and upper lip raiser (AU10) occurrences, while more lip corner pulling (AU12) went along with lower cortisol reactivity. More frequent eyelid tightener (AU07) occurrences were linked to higher subjective stress reactivity but decreased heart rate and HF-HRV reactivity. Last, women showed greater stress-induced smiling intensity and occurrence rates than men. We conclude that psychosocial stress reactivity is systematically linked to facial muscle activity, with distinct facial stress profiles emerging for different stress markers. From all the AUs studied, eyelid tightening (AU07) seems to provide the strongest potential for future attempts of diagnosing phases of acute stress via facial activity.

Stress affects the prediction of others' behavior.

Predicting behavior of other people is vital for successful social interactions. We tested whether a stress-induced cortisol increase affects healthy young men's prediction of another individual's behavior. Forty-two participants were randomly assigned to a stress or to a control condition. Afterwards, they participated in a modified false-belief task that not only tests false-belief understanding but also the tendency to predict another person's future behavior based on his former behavior. Subjective ratings and salivary cortisol concentrations revealed a successful stress induction. Stress did not affect participants' attribution of false beliefs but it increased the probability to predict that a protagonist would act according to his former behavior. Recognizing that stress fosters the interpretation of others' behavior following their former behavior and not their current goals extends previous research showing that stress fosters our own habitual behavior.

Adult age differences in the psychophysiological response to acute stress

Age-related differences in the psychophysiology of the acute stress response are poorly understood given the limited number of studies and the high heterogeneity of findings. The present study contributes by investigating age differences in both the psychological and physiological responses to acute stress in a sample of healthy younger (N = 50; 18–30; Mage = 23.06; SD = 2.90) and older adults (N = 50; 65–84; Mage = 71.12; SD = 5.02). Specifically, the effects of psychosocial stress (i.e., age-adapted Trier Social Stress Test) were investigated at numerous timepoints throughout the stress response phases (i.e., baseline, anticipation, reactivity, recovery) on cortisol, heart rate, subjective stress, and anticipatory appraisal of the stressful situation. The study was conducted in a between-subject (younger vs. older) cross-over (stress vs. control) design. Results revealed age-related differences in both physiological and psychological variables: older adults had overall lower salivary cortisol levels in the stress and control conditions and lower stress-induced cortisol increase (i.e., AUCi). In addition, older adults’ cortisol reactivity was delayed compared to younger adults. Older adults showed a lower heart rate response in the stress condition while no age differences were observed in the control condition. Finally, older adults reported less subjective stress and a less negative stress appraisal during the anticipation phase than younger adults, which could potentially explain lower physiological reactivity in this age group. Results are discussed in relation to the existing literature, potential underlying mechanisms, and future directions for the field.

The role of sex hormones in targeting stress-induced tobacco craving, stress-reactivity, and smoking with guanfacine among women who smoke

Women who smoke are particularly vulnerable to tobacco craving, smoking behaviors, and relapse in the context of stress when compared to men who smoke. One factor in this sex difference may be sex hormones, including estradiol and progesterone; however, smoking cessation medication trials often do not explore the impact of sex hormones on drug effects. This secondary analysis of a double-blind, placebo-controlled study explored the impact of levels of actual estradiol and progesterone on guanfacine, a noradrenergic α2a agonist, which attenuates stress-induced smoking behaviors in women. Women who smoke (n = 43) completed a stress induction laboratory paradigm followed by an ad-libitum smoking period. Assessment of tobacco craving, and stress-reactivity (via cortisol response) occurred pre- and post-stress induction. Results indicated that guanfacine attenuated stress-induced tobacco craving (F = 10.94, p = 0.02) and cortisol response (F = 14.23, p < 0.001); however, high levels of estradiol overrode guanfacine's effect on craving (F = 4.00, p = 0.05), cortisol response (F = 14.23, p < 0.001), and smoking during the ad-libitum period (F = 12.23, p = 0.001). Additionally, progesterone proved to be protective against tobacco craving and enhanced guanfacine's medication effect on craving (F = 5.57, p = 0.02). The present study found that sex hormones had a significant impact on medication effects in a smoking cessation trial and thus underscore the importance of examining the role of sex hormones in future medication trials.

Hair Cortisone Predicts Lower Stress-induced Salivary Cortisol Response: Resting-state Functional Connectivity Between Salience and Limbic Networks

Previous studies revealed that high long-term hypothalamic–pituitaryadrenal (HPA) axis activity measured by the hair cortisol concentrations predicts lower acute stress cortisol response and reported the influences of hair cortisol on brain activity during acute stress exposure. However, considering that long-term HPA axis activity has a close relationship with the brain’s resting-state functional connectivity (RSFC), the current study aimed to explore the role of RSFC between limbic and salience network in this relationship. Seventy-seven healthy participants underwent resting-state imaging scans before performing the acute ScanSTRESS task. Saliva samples were collected to assess the levels of acute stress salivary cortisol. Hair samples were also collected, and the corticosteroid concentration extracted from these samples were used as a biomarker of long-term HPA axis activity. High hair cortisone (HairE) levels predicted lower acute stress cortisol response. Moreover, high HairE levels were significantly correlated with enhanced RSFC between limbic and salience networks, while RSFC was negatively associated with acute stress cortisol response. Importantly, the RSFC between left insula and left parahippocampus mediated the association between HairE and acute cortisol stress response. Taken together, this study uncovers the important role of RSFC between salience and limbic networks in the long-term relationship between HairE and acute cortisol response and contributes to a deeper understanding of the individual differences in acute stress response.

Fostered offspring develop hyper-reactive endocrine stress responses in a plural-breeding rodent, Octodon degus

Long-term parental separation can lead to altered behavioral and physical development in human children. Rodent models are popular for studying parent–child separation, and several studies have found that maternal separation leads to chronic changes in the endocrine stress response. However, while human children are generally raised by multiple caregivers, most rodent studies utilize solitary breeding species. Therefore, we used degus (Octodon degus) as a model for studying human parental separation, as these rodents practice plural breeding and communal care. In this study, we cross-fostered degu litters at different ages (post-natal day [PND] 2, 8, and 14) to test the hypotheses that fostering affects offspring stress hormone levels in both the short- and long-term and that these impacts differ depending on the age at which offspring are fostered. We found that fostering had long-term effects, as fostered offspring had higher stress-induced cortisol levels and weaker cortisol negative feedback than non-fostered offspring at weaning age (PND28). We also found that the timing of fostering mattered, as degus fostered at PND8 had higher baseline cortisol levels the day after fostering, while degus fostered at PND2 had higher stress-induced cortisol levels at weaning. These data suggest that long-term cross-fostering has enduring impacts on the endocrine stress response in degus, therefore making them a useful model organism for investigating impacts of parental separation in humans.

Childhood adversity and acute stress vulnerability at adulthood: The mediating role of sleep

IntroductionNumerous preclinical and clinical studies established the contribution of childhood adversity to acute stress vulnerability at adulthood. Several different physiological, psychological and behavioral factors have been suggested as putative mediators of this association. Sleep, and more specifically sleep disruption, has emerged as one such promising candidate. First, adverse childhood experiences have been repeatedly associated with adult sleep disorders. Second, individuals that suffer from stress-related psychopathology at adulthood often exhibit sleep disturbances, to the extent that sleep difficulties are diagnostic criteria for many of these disorders. Third, inefficient sleep pre and post exposure to acute stress was shown to increase the likelihood for maladaptive outcome, potently by impairing critical processes that occur during sleep as arousal regulation and memory consolidation.ObjectivesTo date, very few studies integrated these independent lines of research. Also, previous studies mostly assessed sleep via self-reported diary or a single night measurement at laboratory settings. The current study aimed to provide a more ecological and continuous account for sleep patterns, and their putative associations with childhood adversity on the one hand and vulnerability to acute stress at adulthood on the other hand.MethodsNinety-six healthy adult female participants completed the well-established childhood trauma questionnaire (CTQ) before wearing a wearable sensor for seven consecutive days and nights while maintaining their regular life routine. Following that, participants all underwent an acute laboratory stress induction procedure while their psychological and endocrine responses were recorded at multiple time points throughout.ResultsSleep patterns fully mediated the association between childhood adversity and psychological response to acute stress at adulthood (Figure 1). Specifically, elevated levels of childhood trauma were associated with more variation in sleep duration across the recording period, which in turn was associated with higher stress-induced negative affect. Interestingly, this association did not emerge with respect to mean sleep time nor with stress-induced cortisol release.ConclusionsResults imply that childhood trauma may lead to irregular sleep patterns which in turn contribute to exaggerated emotional response to acute stress at adulthood. These findings support the mediating role of sleep in the link between childhood adversity and acute stress vulnerability at adulthood, and highlight sleep as a viable target for early or even preventive intervention.Disclosure of InterestNone Declared

Separating the influences of means and daily variations of sleep on the stress-induced salivary cortisol response

BackgroundPrevious research regarding the effects of sleep quality and quantity on the acute stress response has yielded inconsistent findings. This may be attributed to various factors, including composite sleep components (i.e., means and daily variations) and mixed cortisol stress response (i.e., reactivity and recovery). Thus, this study aimed to separate the effects of means and daily variations of sleep on the reactivity and recovery of cortisol responses to psychological challenges. MethodsIn study 1, we recruited 41 healthy participants (24 women; age range, 18–23 years), monitored their sleep during seven consecutive days via wrist actigraphy and sleep diaries, and adopted the Trier Social Stress Test (TSST) paradigm to induce acute stress. Study 2 consisted of a validation experiment using the ScanSTRESS paradigm, which included 77 additional healthy individuals (35 women; age range, 18–26 years). Similarly to the TSST, the ScanSTRESS induces acute stress using uncontrollability and social evaluation. In both studies, saliva samples from the participants were collected before, during, and after the acute stress task. ResultsUsing residual dynamic structural equation modeling, both study 1 and study 2 demonstrated that higher means of objective sleep efficiency, and longer means of objective sleep duration were related to greater cortisol recovery. In addition, fewer daily variations in objective sleep duration were associated with greater cortisol recovery. However, there was no correlation between sleep variables and cortisol reactivity, except for the daily variations in objective sleep duration in study 2. No correlation was observed between subjective sleep and cortisol response to stress. ConclusionsThe present study separated two features of multi-day sleep patterns and two components of cortisol stress response, providing a more comprehensive picture of the effect of sleep on the stress-induced salivary cortisol response, and contributing to the future development of targeted interventions for stress-related disorders.

Gut microbiome composition associates with corticosteroid treatment, morbidity, and senescence in Chinook salmon (Oncorhynchus tshawytscha)

Pacific salmon experience prolonged elevation in corticosteroid hormones during important life history events including migration, reproduction, and senescence. These periods of elevated corticosteroids correspond with changes to immunity and energy metabolism; therefore, fish may be particularly vulnerable to mortality at these times. Recent studies found that stress-induced cortisol release associated with microbial community shifts in salmonids, raising the question of how longer-term corticosteroid dynamics that accompany life history transitions affect salmonid microbiomes. In this work, we experimentally evaluated the relationships between gut microbiome composition, chronically elevated corticosteroids, and mortality in juvenile Chinook salmon (Oncorhynchus tshawytscha). We found that treatment with slow-release implants of the corticosteroids cortisol or dexamethasone resulted in changes to the gut microbiome. Morbidity was also associated with microbiome composition, suggesting that the gut microbiome reflects individual differences in susceptibility to opportunistic pathogens. Additionally, we analyzed a small number of samples from adult fish at various stages of senescence. Results from these samples suggest that microbiome composition associated with gut integrity, and that the microbial communities of corticosteroid treated juveniles shift in composition toward those of senescent adults. Overall, findings from this work indicate that the gut microbiome correlates with mortality risk during periods of chronic corticosteroid elevation.

Yoga and the Need of Its Integration in Modern Medicine.

Growing evidences of the health benefits of yoga are available in the literature. But physicians are not aware of it. Databases like PubMed, PubMed Central, Google Scholar, and Scopus are searched for the articles on preventive, therapeutic, and rehabilitation potential of yoga. Scientific evidences available are analyzed and incorporated into the article. Yoga provides relief from stress, anxiety, depression, and obsessive thoughts. It promotes better sleep. It relieves psychosomatic disorders. Yoga helps to cope with post-traumatic stress disorder (PTSD). Pranayama appears to alter autonomic responses by breath-holding that increases vagal tone and decreases sympathetic discharge and causes relaxation. Yoga increases GABAergic activity that has an anxiolytic effect. Yoga reduces stress-induced cortisol release and reduces hyperglycemia. Yoga reduces seizure frequencies, prevents rapid cognitive decline in Alzheimer's disease, and helps in poststroke rehabilitation. Reduction of blood pressure and heart rate are seen with yoga. Yoga increases heart rate variability (HRV) and reduces health consequences of allostatic overload. Pranayama improves the vital capacity of lungs. Yoga improves musculoskeletal flexibility and enhances the ability of sustained isometric muscle contraction. Yoga is proved to be a viable adjunct of drug therapy for depression and anxiety. It is a promising alternative to psychoanalysis and cognitive behavior therapy. Yoga prevents lifestyle disorders. Yoga is safe and affordable. Integration of yoga in modern medicine needs intensification because of its various health-promoting, disease-preventing, therapeutic, and rehabilitative effects.

The modulation of acute stress on model-free and model-based reinforcement learning in gambling disorder.

Experiencing acute stress is common in behavioral addictions such as gambling disorder. Additionally, like most substance-induced addictions, aberrant decision-making wherein a reactive habit-induced response (conceptualized as a Model-free [MF] in reinforcement learning) suppresses a flexible goal-directed response (conceptualized as a Model-based [MB]) is also common in gambling disorder. In the current study we investigated the influence of acute stress on the balance between habitual response and the goal-directed system. A sample of N = 116 problem gamblers (PG) and healthy controls (HC) performed an acute stress task - the Socially Evaluated Cold pressure task (SECPT) - or a control task. Self-reported stress and salivary cortisol were collected as measures of acute stress. Following the SECPT, participants performed the Two-Step Markov Task to account for the relative contribution of MB and MF strategies. Additionally, verbal working memory and IQ measures were collected to account for their mediating effects on the orchestration between MB/MF and the impact of stress. Both groups had comparable baseline and stress-induced cortisol response to the SECPT. Non-stressed PG displayed lower MB learning than HC. MANOVA and regression analyses showed a deleterious effect of stress-induced cortisol response on the orchestration between MB and MF learning in HC but not in PG. These effects remained when controlling for working memory and IQ. We found an abnormal pattern of modulation of stress on the orchestration between MB and MF learning among PG. Several interpretations and future research directions are discussed.

Normalizing the Optical Signal Enables Robust Assays with Lateral Flow Biosensors.

Lateral flow assays (LFAs) are widely adopted for fast, on-site molecular diagnostics. Obtaining high-precision assay results, however, remains challenging and often requires a dedicated optical setup to control the imaging environment. Here, we describe quick light normalization exam (qLiNE) that transforms ubiquitous smartphones into a robust LFA reader. qLiNE used a reference card, printed with geometric patterns and color standards, for real-time optical calibration: a photo of an LFA test strip was taken along with the card, and the image was processed using a smartphone app to correct shape distortion, illumination brightness, and color imbalances. This approach yielded consistent optical signal, enabling quantitative molecular analyses under different illumination conditions. We adapted qLiNE to detect cortisol, a known stress hormone, in saliva samples at point-of-use settings. The assay was fast (15 min) and sensitive (detection limit, 0.16 ng/mL). The serial qLiNE assay detected diurnal cycles of cortisol levels as well as stress-induced cortisol increase.

Empathy Modulates the Effect of Stress Reactivity on Generous Giving.

How does acute stress influence the degree to which we cooperate with others? Research on the effects of stress on social decision-making is guided by two seemingly contrasting theories. Acute stress may trigger a Fight-or-Flight response, manifested by increased anxiety, and more egocentric or selfish behavior. Alternatively, according to the Tend-and-Befriend model, acute stress may induce affiliative behaviors, marked by increased prosociality in an effort to seek and receive social support and protection. Extant studies on the topic do not provide consistent support for either pattern of behavior, with studies showing evidence for both Fight-or-Flight or Tend-and-Befriend like responses. One possibility, may be the nature of social responses to stressful situations differ as a function of the individual. In the current study, we demonstrate an example of such a person-by-situation interaction, showing that acute stress can cause either pro-social or selfish responses, contingent on individual differences in trait empathy. One hundred and twenty three participants (60 F) were assessed for trait empathy using the Interpersonal Reactivity Index; consequently, they underwent either the Trier Social Stress Test—a well-validated paradigm for eliciting acute psychosocial stress—or a non-stress inducing control condition. Following exposure to either the stress or control condition, participants played a one-shot Dictator Game to evaluate their generosity levels. Statistical analyses revealed that acute stress by itself did not affect the amount transferred in the Dictator Game. Rather, individual differences in trait empathy moderated the effects of stress on giving. Elevations in stress-induced cortisol resulted in more generous behavior, but only in individuals high in empathy. In contrast, in individuals low in empathy, a greater rise in stress-induced cortisol resulted in more selfish behavior. Effects were more pronounced in females than males. Our findings highlight the necessity of integrating personality traits as important moderators of the link between stress and sociality.

Cortisol reactivity impairs suppression-induced forgetting

To some extent, we can shape our recollections by intentionally remembering certain experiences while trying to forget others, for example, by intentional suppression. Acute stress impairs suppression-induced forgetting of memories. It is unclear, however, whether these deficits are a direct consequence of the acute stress-induced cortisol response. The present study was designed to examine the stress-induced impairment in suppression-induced forgetting in a subgroup of cortisol responders. We exposed healthy participants to a stress (n = 55) or no-stress control (n = 32) version of the Maastricht Acute Stress Test before they performed the Think / No-Think task. Here, participants aimed to repeatedly retrieve or suppress memories of previously learned cue-target video clips to mimic the complexity of episodic memories. Results on the subsequent memory test revealed that, while the no-stress controls and cortisol non-responders demonstrated suppression-induced forgetting, this effect was absent in cortisol responders. Moreover, the magnitude of suppression-induced forgetting was negatively correlated to stress-induced cortisol increases. The current study extends findings on stress-induced impairments in suppression-induced forgetting by specifically focusing on cortisol reactivity. Furthermore, our findings show the importance of individual differences in cortisol responses as a driving mechanism behind stress-induced alterations in our capacity to actively control our memory.

Exploring sex differences in fetal programming for childhood emotional disorders

In examining maternal depression, placental 11β-HSD2 mRNA expression and offspring cortisol regulation as a potential fetal programming pathway in relation to later child emotional disorders, it has become clear that sex differences may be important to consider. This study reports on data obtained from 209 participants in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS) recruited before 20 weeks of pregnancy. Maternal depressive disorders were diagnosed using the SCID-IV and maternal childhood trauma using the Childhood Trauma Questionnaire. Placental 11β-HSD2 mRNA was measured using qRT-PCR. For assessment of stress-induced cortisol reactivity, salivary cortisol samples were taken at 12 months of age. At 4 years of age, measurement of Childhood Emotional Disorders (depression and anxiety) was based on maternal report using the Preschool Age Psychiatric Assessment (PAPA) and internalizing symptoms using the Child Behavior Checklist (CBCL). Maternal depression in pregnancy and postpartum, and infant cortisol reactivity, was associated with internalizing symptoms for females only. For female offspring only, increased 12-month cortisol reactivity was also associated with increased emotional disorders at 4 years of age; however, there was no association with placental 11β-HSD2 mRNA expression. In females only, the combination of lower placental 11β-HSD2 mRNA expression and higher cortisol reactivity at 12 months of age predicted increased internalising problems. These findings suggest there may be sex differences in prenatal predictors and pathways for early childhood depression and anxiety symptoms and disorder.

Maternal stress and the maternal microbiome have sex-specific effects on offspring development and aggressive behavior in Siberian hamsters (Phodopus sungorus)

The gut microbiome, a community of commensal, symbiotic and pathogenic bacteria, fungi, and viruses, interacts with many physiological systems to affect behavior. Prenatal experiences, including exposure to maternal stress and different maternal microbiomes, are important sources of organismal variation that can affect offspring development. These physiological systems do not act in isolation and can have long-term effects on offspring development and behavior. Here we investigated the interactive effects of maternal stress and manipulations of the maternal microbiome on offspring development and social behavior using Siberian hamsters, Phodopus sungorus. We exposed pregnant females to either a social stressor, antibiotics, both the social stressor and antibiotics, or no treatment (i.e., control) over the duration of their pregnancy and quantified male and female offspring growth, gut microbiome composition and diversity, stress-induced cortisol concentrations, and social behavior. Maternal antibiotic exposure altered the gut microbial communities of male and female offspring. Maternal treatment also had sex-specific effects on aspects of offspring development and aggressive behavior. Female offspring produced by stressed mothers were more aggressive than other female offspring. Female, but not male, offspring produced by mothers exposed to the combined treatment displayed low levels of aggression, suggesting that alteration of the maternal microbiome attenuated the effects of prenatal stress in a sex-specific manner. Maternal treatment did not affect non-aggressive behavior in offspring. Collectively, our study offers insight into how maternal systems can interact to affect offspring in sex-specific ways and highlights the important role of the maternal microbiome in mediating offspring development and behavior.

The Effects of Rosiglitazone on Task Specific Anxiety-Like Behavior and Novelty Seeking in a Model of Chronic Adolescent Unpredictable Stress.

Adolescence is characterized as a period of increased social behavior, risk taking, and novelty seeking, partly due to ongoing maturation in critical brain areas and the hypothalamic-pituitary-adrenal (HPA) negative-feedback system. During this period there is heightened vulnerability to stress that can drive neuro-immune-endocrine remodeling, resulting in the emergence of maladaptive behaviors that increase susceptibility to alcohol and substance abuse. Here we used a rat model to investigate the impact of chronic adolescent unpredictable stress on a battery of behavioral measures to assess anxiety, novelty seeking, risk taking, depression, and voluntary ethanol consumption while determining whether the PPARγ agonist rosiglitazone can attenuate these effects. Adolescent female rats that experienced stress showed increased risk taking behavior and novelty seeking behavior with no change in ethanol consumption. The administration of rosiglitazone during stress induction attenuated stress-induced cortisol elevation, normalized risk taking behavior in a model anxiety, and attenuated novelty seeking in a task-specific manner. Depressive-like behavior was not impacted by adolescent unpredictable stress or the administration of rosiglitazone. The results from this study demonstrate that exposure to unpredictable stress during adolescence increases the prevalence of maladaptive behaviors that are known to increase susceptibility to alcohol and substance abuse, and that rosiglitazone may be an effective therapeutic to attenuate the emergence of select risk taking and novelty seeking behaviors in females.

Lactobacillus rhamnosus CNCM I-3690 decreases subjective academic stress in healthy adults: a randomized placebo-controlled trial

ABSTRACT Psychological stress negatively affects the intestinal barrier function in animals and humans. We aimed to study the effect of Lactobacillus rhamnosus CNCM I-3690 on intestinal permeability and stress-markers during public speech. Healthy students were randomized to L. rhamnosus-containing (test) or acidified (placebo) milk consumed twice daily for 4 weeks, with 46 subjects per treatment group. Small intestinal permeability was quantified by a 2 h urinary lactulose–mannitol ratio (LMR, primary outcome), fractional excretion of lactulose (FEL) and mannitol (FEM). Salivary cortisol, State-Trait Anxiety Inventory (STAI) and Perceived Stress scores (PSS) were collected. No between-treatment differences were found for LMR (p = .71), FEL or FEM. Within-treatment analyses showed similar LMR and FEL but a stress-induced increase of FEM with the placebo (p < .05) but not test product. Despite a similar increase in salivary cortisol, the stress-induced increase in STAI was significantly lower with the test product vs. placebo (p = .01). Moreover, a stress-preventative effect of the probiotic was found for PSS and more pronounced in subjects with high stress-induced cortisol (p = .01). While increased FEM was mediated by salivary cortisol levels, the effect of the test product on subjective stress was not mediated by changes in FEM. No serious adverse events occurred. In conclusion, we demonstrated that L. rhamnosus CNCM I-3690 prevented stress-induced hyperpermeability to mannitol. Subjective but not objective stress-markers were reduced with L. rhamnosus vs. placebo, suggesting anxiolytic effects, which were independent of barrier stabilization and attractive for the reduction of stress in both health and disease. Clinicaltrials.gov, number NCT03408691.

The impact of myocardial infarction on basal and stress-induced heart rate variability and cortisol secretion in women: A pilot study

Coronary heart disease (CHD), of which myocardial infarction (MI) is a subtype, is the leading cause of death for women. Nonetheless, women remain neglected in CHD research, resulting in treatments and recommendations being primarily based on data collected in men. Pre-clinical and clinical studies have supported dysregulation of the hypothalamic-pituitary-adrenal axis (HPAA) following cardiac arrest and MI to promote the development of mental health disorders (e.g., major depressive disorder, post-traumatic stress disorder). However, studies addressing changes in HPAA activation under basal and stress-induced conditions in women samples have been lacking. Thus, we conducted this study to determine basal and stress-induced changes in heart rate, respiration and cortisol secretion (via 8 saliva samples) in a sample of women with a history of MI (n = 13) and a control group (n = 16). We measured altered stress reactivity through exposure to the Trier Social Stress Test. In addition, participants completed questionnaires assessing perceived stress and mental health status (i.e., anxiety and mood). Overall, our findings indicated comparable assessments of perceived situational stress in both groups. Interestingly, salivary cortisol secretion support reduced stress-induced HPAA activation related to TSST exposure in MI women compared to control counterparts. Our observations are consistent with findings supporting glucocorticoid resistance noted following MI and cardiac arrest. Akin to cardiac arrest survivors, HPAA dysregulation in MI survivors could have an impact on the development of mental health disorders. More studies are needed to address this critical question.

Coping With Urban Habitats Via Glucocorticoid Regulation: Physiology, Behavior, and Life History in Stream Fishes.

As environments become urbanized, tolerant species become more prevalent. The physiological, behavioral and life-history mechanisms associated with the success of such species in urbanized habitats are not well understood, especially in freshwater ecosystems. Here, we examined the glucocorticoid (GC) profiles, life-history traits, and behavior of two species of fish across a gradient of urbanization to understand coping capacity and associated trade-offs. We studied the tolerant live-bearing Western Mosquitofish (Gambusia affinis) for two years and the slightly less tolerant, egg-laying, Blacktail Shiner (Cyprinella venusta) for one year. We used a water-borne hormone method to examine baseline, stress-induced, and recovery cortisol release rates across six streams with differing degrees of urbanization. We also measured life-history traits related to reproduction, and for G. affinis, we measured shoaling behavior and individual activity in a novel arena. Both species showed a trend for reduced stress responsiveness in more urbanized streams, accompanied by higher reproductive output. Although not all populations fit this trend, these results suggest that GC suppression may be adaptive for coping with urban habitats. In G. affinis, GC recovery increased with urbanization, and individuals with the lowest stress response and highest recovery had the greatest reproductive allotment, suggesting that rapid return to baseline GC levels is also an important coping mechanism. In G. affinis, urban populations showed altered life-history trade-offs whereas behavioral traits did not vary systematically with urbanization. Thus, these tolerant species of fish may cope with anthropogenically modified streams by altering their GC profiles and life-history trade-offs. These results contribute to understanding the mechanisms driving species-specific adaptations and thereby community structure in freshwater systems associated with land-use converted areas.