Stress revisited: a critical evaluation of the stress concept

Assessment of autonomic symptom scales in patients with neurodevelopmental diagnoses using electronic health record data

Background

Sleep disturbances, gastrointestinal problems, and atypical heart rate are commonly observed in patients with autism spectrum disorder (ASD) and may relate to underlying function of the autonomic nervous system (ANS). The overall objective of the current study was to quantitatively characterize features of ANS function using symptom scales and available electronic health record (EHR) data in a clinically and genetically characterized pediatric cohort.

Methods

We assessed features of ANS function via chart review of patient records adapted from items drawn from a clinical research questionnaire of autonomic symptoms. This procedure coded for the presence and/or absence of targeted symptoms and was completed in 3 groups of patients, including patients with a clinical neurodevelopmental diagnosis and identified genetic etiology (NPD, n=244), those with an ASD diagnosis with no known genetic cause (ASD, n=159), and age and sex matched controls (MC, n=213). Symptoms were assessed across four main categories: (1) Mood, Behavior, and Emotion; (2) Secretomotor, Sensory Integration; (3) Urinary, Gastrointestinal, and Digestion; and (4) Circulation, Thermoregulation, Circadian function, and Sleep/Wake cycles.

Results

Chart review scores indicate an increased rate of autonomic symptoms across all four sections in our NPD group as compared to scores with ASD and/or MC. Additionally, we note several significant relationships between individual differences in autonomic symptoms and quantitative ASD traits.

Conclusion

These results highlight EHR review as a potentially useful method for quantifying variance in symptoms adapted from a questionnaire or survey. Further, using this method indicates that autonomic features are more prevalent in children with genetic disorders conferring risk for ASD and other neurodevelopmental diagnoses.

The impact of life stress on hallmarks of aging and accelerated senescence: Connections in sickness and in health

Chronic stress is a risk factor for numerous aging-related diseases and has been shown to shorten lifespan in humans and other social mammals. Yet how life stress causes such a vast range of diseases is still largely unclear. In recent years, the impact of stress on health and aging has been increasingly associated with the dysregulation of the so-called hallmarks of aging. These are basic biological mechanisms that influence intrinsic cellular functions and whose alteration can lead to accelerated aging. Here, we review correlational and experimental literature (primarily focusing on evidence from humans and murine models) on the contribution of life stress - particularly stress derived from adverse social environments - to trigger hallmarks of aging, including cellular senescence, sterile inflammation, telomere shortening, production of reactive oxygen species, DNA damage, and epigenetic changes. We also evaluate the validity of stress-induced senescence and accelerated aging as an etiopathological proposition. Finally, we highlight current gaps of knowledge and future directions for the field, and discuss perspectives for translational geroscience.

Oxidative Stress-Induced Liver Damage and Remodeling of the Liver Vasculature

As an organ critically important for targeting and clearing viruses, bacteria, and other foreign material, the liver operates via immune-tolerant, anti-inflammatory mechanisms indispensable to the immune response. Stress and stress-induced factors disrupt the homeostatic balance in the liver, inflicting tissue damage, injury, and remodeling. These factors include oxidative stress (OS) induced by viral infections, environmental toxins, drugs, alcohol, and diet. A recurrent theme seen among stressors common to multiple liver diseases is the induction of mitochondrial dysfunction, increased reactive oxygen species expression, and depletion of ATP. Inflammatory signaling additionally exacerbates the condition, generating a proinflammatory, immunosuppressive microenvironment and activation of apoptotic and necrotic mechanisms that disrupt the integrity of liver morphology. These pathways initiate signaling pathways that significantly contribute to the development of liver steatosis, inflammation, fibrosis, cirrhosis, and liver cancers. In addition, hypoxia and OS directly enhance angiogenesis and lymphangiogenesis in chronic liver diseases. Late-stage consequences of these conditions often narrow the outcomes for liver transplantation or result in death. This review provides a detailed perspective on various stress-induced factors and the specific focus on role of OS in different liver diseases with special emphasis on different molecular mechanisms. It also highlights how resultant changes in the liver vasculature correlate with pathogenesis.

Left dorsolateral prefrontal cortex activation can accelerate stress recovery: A repetitive transcranial stimulation study

In this study, a single high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) session was applied over the left dorsolateral prefrontal cortex (DLPFC) after a moderate-to-intense stressor to investigate whether left DLPFC stimulation could regulate cortisol concentration after stress induction. Participants were randomly divided into three groups (stress-TMS, stress, and placebo-stress). Stress was induced in both the stress-TMS and stress groups using the Trier Social Stress Test (TSST). The placebo-stress group received a placebo TSST. In the stress-TMS group, a single HF-rTMS session was applied over the left DLPFC after TSST. Cortisol was measured across the different groups, and each group's responses to the stress-related questionnaire were recorded. After TSST, both the stress-TMS and stress groups reported increased self-reported stress, state anxiety, negative affect, and cortisol concentration compared with the placebo-stress group, indicating that TSST successfully induced a stress response. Compared with the stress group, the stress-TMS group exhibited reduced cortisol levels at 0, 15, 30, and 45 min after HF-rTMS. These results suggest that left DLPFC stimulation after stress induction might accelerate the stress recovery.

Using the Research Domain Criteria as a framework to integrate psychophysiological findings into stress management and psychotherapy interventions

Research on the psychophysiology of stress is expanding rapidly, but the field lacks a clear integrative framework to help translate research findings into empirically supported stress interventions. The Research Domain Criteria (RDoC) is an excellent candidate to explore as a framework to integrate stress research. The RDoC framework is a dimensional, multi-modal approach to psychopathology proposed as an alternative to categorical approaches used by the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual (DSM). The goal of this paper is to explore the RDoC as a framework to integrate psychophysiology research into therapeutic interventions for stress. The RDoC consists of six domains: negative valence systems, positive valence systems, cognitive systems, social processes systems, arousal/regulatory systems, and sensorimotor systems, and provides an excellent structure for integrating information from multiple levels of functioning including physiology, behavior, and self-report, as well as genes, molecules, cells, and brain circuits. Integrating psychophysiological research on stress using the RDoC framework can direct and amplify stress management and psychotherapeutic interventions. First, the RDoC provides a clear foundation for conceptualizing the stress response in terms of important concepts such as allostasis and adaptation. In this perspective, the terms "allostatic response" or "adaptation response" are more descriptive terms than "stress response" in understanding bodily responses to life threats and challenges. Second, psychophysiological approaches can be used in the context of modalities such as biofeedback and mindfulness to both collect psychophysiological data and then integrate that data into a broader therapeutic framework. Heart rate variability (HRV) biofeedback is being used more frequently as part of a therapeutic intervention package with stress management and psychotherapy, and HRV data is also used to provide outcome evidence on the efficacy of treatment. Mindfulness practices are commonly used in combination with stress management and psychotherapy, and psychophysiological data (HRV, EEG, blood pressure, etc.) is often collected to explore and understand mind/body relationships. In conclusion, the lack of a clear framework to assess and understand mind/body functioning limits current stress research and interventions. The RDoC provides a strong framework to assess and integrate physiological and psychological data and improve stress interventions.

Chronic stress and turnover intention of resident physicians after experiencing COVID-19

BACKGROUND

Previous studies have explored the stress and turnover intention of healthcare workers, but as important backup talents in the healthcare system, resident physicians have received little attention from researchers, especially after experiencing COVID-19. Therefore, this study aims to evaluate the chronic stress and turnover intention of resident physicians after experiencing COVID-19.

METHODS

From June to August 2022, we conducted a questionnaire survey on resident physicians in the Children's Hospital of Hebei Province through the online platform (Wenjuanxing) to evaluate their chronic stress and turnover intention after experiencing COVID-19. For the collected data, we used frequency and percentage to make the statistical description, the Chi-square test to make a univariate analysis on the scores of chronic stress and turnover intention scale, and binary logistic regression analysis to explore the influencing factors of turnover intention.

RESULTS

Out of 143 respondents, we finally received 127 questionnaires, with a response rate of 88.81%. Among 127 respondents, 80.31% of resident physicians experienced varying degrees of chronic stress (mild: 36.22%, moderate: 35.43%, severe: 8.66%), and 74.80% of resident physicians showed varying degrees of turnover intention (mild: 23.62%, moderate: 37.79%, severe: 13.39%). Moreover, age (OR = 0.772, P = 0.042), identity (OR = 8.648, P = 0.021), and chronic stress levels (mild: OR = 6.938, P = 0.003; moderate: OR = 44.049, P < 0.003; severe: OR = 46.141, P = 0.004) can significantly affect turnover intention.

CONCLUSION

In this study, we reported a relatively high proportion of resident physicians with high chronic stress and high turnover intention after experiencing COVID-19. We suggest that the relevant departments should pay more attention to the resident physicians' group and formulate corresponding measures to solve the problems faced by the resident physicians and ensure the stability of the health human resources.

A scoping review of emotions and related constructs in simulation-based education research articles

BACKGROUND

While acknowledgement of emotions' importance in simulation-based education is emerging, there are concerns regarding how education researchers understand the concept of emotions for them to deliberately incorporate emotionally charged scenarios into simulation-based education. This concern is highlighted especially in the context of medical education often lacking strong theoretical integration. To map out how current simulation-based education literature conceptualises emotion, we conducted a scoping review on how emotions and closely related constructs (e.g. stress, and emotional intelligence) are conceptualised in simulation-based education articles that feature medical students, residents, and fellows.

METHODS

The scoping review was based on articles published in the last decade identified through database searches (EMBASE and Medline) and hand-searched articles. Data extraction included the constructs featured in the articles, their definitions, instruments used, and the types of emotions captured. Only empirical articles were included (e.g. no review or opinion articles). Data were charted via descriptive analyses.

RESULTS

A total of 141 articles were reviewed. Stress was featured in 88 of the articles, while emotions and emotional intelligence were highlighted in 45 and 34 articles respectively. Conceptualisations of emotions lacked integration of theory. Measurements of emotions mostly relied on self-reports while stress was often measured via physiological and self-report measurements. Negative emotions such as anxiety were sometimes seen as interchangeable with the term stress. No inferences were made about specific emotions of participants from their emotional intelligence.

CONCLUSIONS

Our scoping review illustrates that learners in simulation-based education are most often anxious and fearful. However, this is partially due to medical education prioritising measuring negative emotions. Further theoretical integration when examining emotions and stress may help broaden the scope towards other kinds of emotions and better conceptualisations of their impact. We call for simulation education researchers to reflect on how they understand emotions, and whether their understanding may neglect any specific aspect of affective experiences their simulation participants may have.

ADSA Foundation Scholar Award: What makes for a good life for transition dairy cows? Current research and future directions

Dairy cows experience several challenges during the transition period, historically defined as the 3 wk before to 3 wk after calving. During this 6-wk window, cows undergo a series of social, nutritional, and physical changes that affect their quality of life. Cows are also at the highest risk of becoming ill in the days and weeks after calving compared with any other period in their adult life. Because of this, the transition cow has been a central focus of dairy cattle research for at least the last 50 yr, with much of this work targeted at identifying, treating, and preventing postpartum disease. However, understanding what makes for a good life for transition cows requires consideration of more than just their health. When considering a cow's welfare, we must also include her emotional experiences and ability to live a reasonably natural life. To gain a broader perspective on the welfare of transition cows that goes beyond their health, continued inter- and transdisciplinary approaches are needed. The aims of this narrative review are to (1) describe a framework used to study animal welfare, which includes different perspectives on what makes for a good life for animals using examples from transition cow research, (2) summarize the advancements we have made in developing our understanding of the welfare of transition dairy cows over the last several decades, (3) identify gaps in the literature and propose new and continued topics for research, and (4) suggest a path forward for researchers, including the use of methods from both the natural and social sciences to rethink existing problems, understanding barriers to adoption of evidence-based practice, and prepare for future challenges.

Conditional on the social environment? Roots of repeatability in hormone concentrations of male guinea pigs

Individual differences in behavioral and physiological traits among members of the same species are increasingly being recognized as important in animal research. On the group level, shaping of behavioral and hormonal phenotypes by environmental factors has been reported in different taxa. The extent to which the environment impacts behavior and hormones on the individual level, however, is rather unexplored. Hormonal phenotypes of guinea pigs can be shaped by the social environment on the group level: pair-housed and colony-housed males differ systematically in average testosterone and stressor-induced cortisol levels (i.e. cortisol responsiveness). The aim of the present study was to evaluate whether repeatability and individual variance components (i.e. between- and within-individual variation) of hormonal phenotypes also differ in different social environments. To test this, we determined baseline testosterone, baseline cortisol, and cortisol responsiveness after challenge in same-aged pair-housed and colony-housed guinea pig males over a period of four months. We found comparable repeatability for baseline cortisol and cortisol responsiveness in males from both social conditions. In contrast, baseline testosterone was repeatable only in males from colonies. Interestingly, this result was brought about by significantly larger between-individual variation of testosterone, that was not explained by differences in dominance rank. Individualized social niches differentiated under complex colony, but not pair housing, could be an explanation for this finding.

The Insidious Influence of Stress: An Integrated Model of Stress, Executive Control, and Psychopathology

Although exposure to acute stress undoubtedly contributes to psychopathology, most individuals do not develop psychopathology following stress exposure. To explain this, biological, emotional, and cognitive responses to stress have been implicated, but individual differences in executive control (i.e., top-down control of cognition and behavior) measured in response to stress has only recently emerged as a potential factor contributing to psychopathology. In this review, we introduce a model-the integrated model of stress, executive control, and psychopathology-positing how the impairing effects of acute stress on executive control can contribute to psychopathology. We link to research on biological, emotional, and cognitive processes, all of which can be impacted by executive control, to propose a framework for how poorer executive control under conditions of acute stress can contribute to psychopathology. This integrated model is intended to further our understanding of who is more susceptible to the negative consequences of stress.

Oxidative stress-induced by different stressors alters kidney tissue antioxidant markers and levels of creatinine and urea: the fate of renal membrane integrity

The cellular integrity of the kidney in homeostatic regulation has constantly been compromised by oxidative stress following exposure to varying nature of stressor present within the environment. The objective of the work was to evaluate the renal effect of the different stressor stimuli applied. Twenty-four adult female rats weighing averagely 160-200 g and within the ages of 12-14 weeks were used for experiment-1, while 12 offspring were utilized for experiment-2. Three stress models namely; restraint, mirror chamber and cat intruder stressors were used. Tissues were isolated from the animal and homogenized for tissue antioxidant assay. Serum was collected for assays of urea and creatinine for the kidney function test using ELISA. Data collected were analyzed for Mean ± SEM using One Way ANOVA. The present study revealed that exposure of rats to different stressors reduced relative kidney weights but did not significantly alter serum creatinine concentration in the Wistar rats, although the concentrations were slightly increased compared to controls. Urea concentration was significantly (p < 0.05) increased in rats exposed to restraint and intruder stressors. Exposure to a mirror chamber stressor did not significantly alter urea concentration. Offspring from parents of stressed female rats exhibited a significant (p < 0.05) increase in serum urea level, minimal increase in serum creatinine levels. GSH and GST levels showed no significant difference when compared to control group, whereas, GPx were significantly (p < 0.05) decreased irrespective of the stressor applied. SOD activity were significantly (p < 0.05) reduced in the group exposed to restraint or cat intruder stressor. CAT activities were significantly (p < 0.05) reduced in the rats exposed to restraint or cat intruder stressor. In all, the different stress model altered the antioxidant capacity of the kidney tissues. Exposure of rats to a stressful condition of the different nature of stressor has the tendency of compromising the functional integrity of the kidney, thus, with the potency of complicating female renal function.

Stress in the social context: a behavioural and eco-evolutionary perspective

The social environment is one of the primary sources of challenging stimuli that can induce a stress response in animals. It comprises both short-term and stable interactions among conspecifics (including unrelated individuals, mates, potential mates and kin). Social stress is of unique interest in the field of stress research because (1) the social domain is arguably the most complex and fluctuating component of an animal's environment; (2) stress is socially transmissible; and (3) stress can be buffered by social partners. Thus, social interactions can be both the cause and cure of stress. Here, we review the history of social stress research, and discuss social stressors and their effects on organisms across early life and adulthood. We also consider cross-generational effects. We discuss the physiological mechanisms underpinning social stressors and stress responses, as well as the potential adaptive value of responses to social stressors. Finally, we identify outstanding challenges in social stress research, and propose a framework for addressing these in future work.

Preclinical Models of Chronic Stress: Adaptation or Pathology?

The experience of prolonged stress changes how individuals interact with their environment and process interoceptive cues, with the end goal of optimizing survival and well-being in the face of a now-hostile world. The chronic stress response includes numerous changes consistent with limiting further damage to the organism, including development of passive or active behavioral strategies and metabolic adjustments to alter energy mobilization. These changes are consistent with symptoms of pathology in humans, and as a result, chronic stress has been used as a translational model for diseases such as depression. While it is of heuristic value to understand symptoms of pathology, we argue that the chronic stress response represents a defense mechanism that is, at its core, adaptive in nature. Transition to pathology occurs only after the adaptive capacity of an organism is exhausted. We offer this perspective as a means of framing interpretations of chronic stress studies in animal models and how these data relate to adaptation as opposed to pathology.

Play as a Stress-Coping Method Among Children in Light of the COVID-19 Pandemic: A Review

The COVID-19 pandemic, which started in early 2020, has been a great source of stress for almost every person all around the world. However, this is particularly true for children. It is necessary to fully address the stress-related psychosocial issues connected with the pandemic, solely in children. Play is important for children's development, as it is a natural activity for every child. Through play and play-based interventions, children can communicate non-verbally, symbolically, and in an action-oriented manner. Therefore, play-based interventions may have the potential to be one of the coping strategies used by children who experience stress, especially during the COVID-19 pandemic. The aim of this narrative review was to show how play-based activities could help children deal with stress related to the COVID-19 pandemic in the non-clinical population. A systematic search of the literature in various databases was performed. The initial search provided 5,004 potentially eligible studies in various databases, and 42,201 records identified from Google Scholar. After excluding studies not meeting the inclusive criteria, nine papers were selected for this narrative review. This narrative review showed findings that play-based activities can have a positive effect during the COVID-19 pandemic on different stress levels in the children population. Additionally, the findings of this review highlight the importance of further research and implementation of play into many aspects of children's life.

The Effects of Interior Materials on the Restorativeness of Home Environments

The effects of a restorative environment on attention restoration and stress reduction have received much attention in societies, especially during the COVID-19 pandemic. Interior materials are a crucial environmental element influencing people's perceived restorativeness at home. Nevertheless, few studies have examined the links between interior materials and the restorativeness of home environments. To address this gap, this study aimed to investigate the restorative potential of interior materials among a sample of adults in China. Cross-sectional data from 85 participants whose professional majors were related to interior design were selected. The measures of the restorative potential of each interior material were obtained by a questionnaire adapted from the semantic differential method. The Wilcoxon signed-rank test was used to compare the restorative potential of interior materials. We found that glass material had the best restorative potential in home environments. Doubts were raised regarding wood material's restorativeness, and more consideration should be granted for designing a restorative home with wood material. In contrast, metal is not recommended for restorative home design. These findings contribute to the evidence of the restorative effects of home design.

Stress specifically deteriorates working memory in peripheral neuropathic pain and fibromyalgia

This study aimed to explore the influence of chronic stress, measured through hair cortisol, on executive functions in individuals with chronic pain. We expected that there would be significant differences in chronic stress and executive functioning between pain patients and healthy controls, as well as between primary and secondary pain classifications. We also hypothesized that hair cortisol concentration was predictive of worse performance on tests of executive functions, controlling for objective and subjective covariates. For this study, 122 participants provided a hair sample (n = 40 with fibromyalgia; n = 24 with peripheral neuropathic pain; n = 58 matched healthy controls). Eighty-four of these participants also completed highly detailed testing of executive functions (n = 40 with fibromyalgia; n = 24 with peripheral neuropathic pain; n = 20 healthy controls). To assess differences in stress levels and executive functions, t-tests were used to compare patients with controls as well as fibromyalgia with peripheral neuropathic pain. Then, univariate regressions were used to explore associations between stress and executive functioning in both chronic pain classifications. Any significant univariate associations were carried over to hierarchical multivariate regression models. We found that patients with chronic pain had significantly higher cortisol levels than healthy controls, but all groups showed similar executive functioning. Hierarchical multiple regression analyses disclosed that in a model controlling for age, sex and pain medication usage, hair cortisol levels explained 8% of the variance in spatial working memory strategy in individuals with chronic pain. The overall model explained 24% of the variance in spatial working memory. In a second model using imputed data, including both objective and subjectively reported covariates, hair cortisol levels explained 9% of the variance, and the full model 31% of the variance in spatial working memory performance. Higher levels of cortisol indicated worse performance. In this study, an applied measure of chronic stress, namely hair cortisol, explained a substantial part of the variance on a spatial working memory task. The current results have important implications for understanding and treating cognitive impairments in chronic pain.

The effects of expected and unexpected stress on inappropriate aggression in simulated police interventions

Here we performed a before-after ABA-design study in police cadets (N = 82) to compare the effects of unexpected (event-triggered) and expected (anticipatory) stressors on aggression. On the first day of the study, participants filled in the Buss-Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale (BIS) and were fitted with heart rate (HR) monitors, which remained attached till the end of the study. On day 2, they were instructed to perform a police intervention in a realistic training environment. The intervention was preceded either by a warning or by a reassuring audio recording that forecasted violent or routine interventions, respectively. Both groups encountered hostile suspects at the intervention site, the behavior of which, however, did not justify the use of force e.g., aggression. The warning resulted in a gradually developing anticipatory stress as shown by HRs. Cadets exposed to the reassuring audio recording showed minimal anticipatory stress but responded to the hostile suspects by an abrupt increase in HRs, which was missing in the warned group. The magnitude of HR responses was similar in the two groups, only their temporal evolution differed. Although aggression showed some associations with BPAQ and BIS scores, the main predictors of behavior were HR changes according to a Multiple Regression analysis. The gradually developing anticipatory stress was associated with low, whereas the abrupt increase in HRs was associated with high aggression. Our findings suggest that the anticipation of a stressful event improves behavioral control whereas an unexpected stress strongly promotes aggression.

Neurocognitive effects of stress: a metaparadigm perspective

Stressful experiences, both physical and psychological, that are overwhelming (i.e., inescapable and unpredictable), can measurably affect subsequent neuronal properties and cognitive functioning of the hippocampus. At the cellular level, stress has been shown to alter hippocampal synaptic plasticity, spike and local field potential activity, dendritic morphology, neurogenesis, and neurodegeneration. At the behavioral level, stress has been found to impair learning and memory for declarative (or explicit) tasks that are based on cognition, such as verbal recall memory in humans and spatial memory in rodents, while facilitating those that are based on emotion, such as differential fear conditioning in humans and contextual fear conditioning in rodents. These vertically related alterations in the hippocampus, procedurally observed after subjects have undergone stress, are generally believed to be mediated by recurrently elevated circulating hypothalamic-pituitary-adrenal (HPA) axis effector hormones, glucocorticoids, directly acting on hippocampal neurons densely populated with corticosteroid receptors. The main purposes of this review are to (i) provide a synopsis of the neurocognitive effects of stress in a historical context that led to the contemporary HPA axis dogma of basic and translational stress research, (ii) critically reappraise the necessity and sufficiency of the glucocorticoid hypothesis of stress, and (iii) suggest an alternative metaparadigm approach to monitor and manipulate the progression of stress effects at the neural coding level. Real-time analyses can reveal neural activity markers of stress in the hippocampus that can be used to extrapolate neurocognitive effects across a range of stress paradigms (i.e., resolve scaling and dichotomous memory effects issues) and understand individual differences, thereby providing a novel neurophysiological scaffold for advancing future stress research.

Optimizing zebrafish rearing-Effects of fish density and environmental enrichment

Introduction

Despite its popularity in research, there is very little scientifically validated knowledge about the best practices on zebrafish (Danio rerio) husbandry, which has led to several facilities having their own husbandry protocols. This study was performed to expand knowledge on the effects of enrichment and fish density on the welfare of zebrafish, with hopes of providing a scientific basis for future recommendations and legislations.

Methods

Zebrafish were reared at three different stocking densities, (1, 3 or 6 fish/L), in tanks with or without environmental enrichment. Agonistic behavior was observed twice a week for 9 weeks directly in the housing tanks. Aspects of welfare is known to be reflected in neuroendocrine stress responses. Thus, cortisol secretion in response to lowering the water level was analyzed for each group. In addition, we assessed cortisol secretion in response to confinement and risk-taking behavior (boldness) using the novel tank diving test for individual fish. At termination of the experiment fish were subjected to stress by transfer to a novel environment and brain tissue was sampled for analysis of brain monoaminergic activity.

Results

Fish kept at the lowest density (1 fish/L) showed a significantly higher level of aggression than fish kept at 3 or 6 fish/L. Moreover, fish kept at this low density showed significantly higher cortisol secretion on a group level than fish kept at the higher stocking densities, when subjected to lowering of the water level. Keeping fish at 1 fish/L also had effects on brain monoamines, these fish showing higher brain dopamine concentrations but lower dopamine turnover than fish kept at higher densities. Neither stocking density or enrichment had any clear effects on the behavior of individual fish in the novel tank diving test. However, fish kept at high densities showed lower and more variable growth rates than fish kept at 1 fish/L.

Discussion

Taken together these results suggest that zebrafish should not be kept at a density of 1 fish/L. The optimal stocking density is likely to be in the range of 3-6 fish/L.

Comparative Assessment of the Stress Response of Cattle to Common Dairy Management Practices

While studies have been conducted examining the stress response of dairy cattle to individual acute and chronic stressors, the results are difficult to compare due to differences in study design and analysis methods. The aim of the present study was to conduct a comparative assessment of the impact of eight common stimuli: artificial insemination (AI), embryo transfer (ET), morning milking (MM), evening milking (EM), veterinary examination (VE), ultrasound examination (US), hoof trimming (HT), and natural breeding (NB) on the hypothalamic-pituitary-adrenal axis and milk production of 24 Holstein-Friesian cattle. After random allocation into control and treatment groups, a total of five blood samples were collected 40 min (Ba1) and 20 min (Ba2) prior to stimulus application, immediately following the stimulus (St), as well as 20 min (Re1) and 40 min (Re2) post-stimulus. A comparison between the overall serum cortisol concentrations in the treatment groups showed a significant difference between HT to AI (p = 0.006), ET (p = 0.010), MM (p = 0.021), VE (p = 0.009), EM (p = 0.007), and US (p = 0.010), except for NB (p = 0.542). There is no significant difference between the control groups (p > 0.05). The stimuli HT (p < 0.001) and NB (p < 0.001) showed significant increases in cortisol following stimulus application, and the levels failed to decrease significantly by sample Re2. No significant differences in daily milk yield (kg) were measured amongst the tested stimuli (p = 0.472) nor amongst the groups 'Control', 'Treatment' and 'no stimulus' (p = 0.350). In conclusion, when factors such as increased physical activity, novel social interaction, sexual arousal, and a more intense restriction of movement are present, the animal's perceived controllability and predictability might decrease, affecting the animal's response to stress. Treatments carried out while animals are restrained in a headlock while remaining within their regular group likely result in a less intense activation of the HPA axis.

Rice Germ Attenuates Chronic Unpredictable Mild Stress-Induced Muscle Atrophy

Chronic stress leads to hypothalamic-pituitary-adrenal axis dysfunction, increasing cortisol levels. Glucocorticoids (GCs) promote muscle degradation and inhibit muscle synthesis, eventually causing muscle atrophy. In this study, we aimed to evaluate whether rice germ supplemented with 30% γ-aminobutyric acid (RG) attenuates muscle atrophy in an animal model of chronic unpredictable mild stress (CUMS). We observed that CUMS raised the adrenal gland weight and serum adrenocorticotropic hormone (ACTH) and cortisol levels, and these effects were reversed by RG. CUMS also enhanced the expression of the GC receptor (GR) and GC-GR binding in the gastrocnemius muscle, which were attenuated by RG. The expression levels of muscle degradation-related signaling pathways, such as the Klf15, Redd-1, FoxO3a, Atrogin-1, and MuRF1 pathways, were enhanced by CUMS and attenuated by RG. Muscle synthesis-related signaling pathways, such as the IGF-1/AKT/mTOR/s6k/4E-BP1 pathway, were reduced by CUMS and enhanced by RG. Moreover, CUMS raised oxidative stress by enhancing the levels of iNOS and acetylated p53, which are involved in cell cycle arrest, whereas RG attenuated both iNOS and acetylated p53 levels. Cell proliferation in the gastrocnemius muscle was reduced by CUMS and enhanced by RG. The muscle weight, muscle fiber cross-sectional area, and grip strength were reduced by CUMS and enhanced by RG. Therefore, RG attenuated ACTH levels and cortisol-related muscle atrophy in CUMS animals.

The scaling of goals from cellular to anatomical homeostasis: an evolutionary simulation, experiment and analysis

Complex living agents consist of cells, which are themselves competent sub-agents navigating physiological and metabolic spaces. Behaviour science, evolutionary developmental biology and the field of machine intelligence all seek to understand the scaling of biological cognition: what enables individual cells to integrate their activities to result in the emergence of a novel, higher-level intelligence with large-scale goals and competencies that belong to it and not to its parts? Here, we report the results of simulations based on the TAME framework, which proposes that evolution pivoted the collective intelligence of cells during morphogenesis of the body into traditional behavioural intelligence by scaling up homeostatic competencies of cells in metabolic space. In this article, we created a minimal in silico system (two-dimensional neural cellular automata) and tested the hypothesis that evolutionary dynamics are sufficient for low-level setpoints of metabolic homeostasis in individual cells to scale up to tissue-level emergent behaviour. Our system showed the evolution of the much more complex setpoints of cell collectives (tissues) that solve a problem in morphospace: the organization of a body-wide positional information axis (the classic French flag problem in developmental biology). We found that these emergent morphogenetic agents exhibit a number of predicted features, including the use of stress propagation dynamics to achieve the target morphology as well as the ability to recover from perturbation (robustness) and long-term stability (even though neither of these was directly selected for). Moreover, we observed an unexpected behaviour of sudden remodelling long after the system stabilizes. We tested this prediction in a biological system-regenerating planaria-and observed a very similar phenomenon. We propose that this system is a first step towards a quantitative understanding of how evolution scales minimal goal-directed behaviour (homeostatic loops) into higher-level problem-solving agents in morphogenetic and other spaces.

Does the Glucocorticoid Stress Response Make Toads More Toxic? An Experimental Study on the Regulation of Bufadienolide Toxin Synthesis

Chemical defense is a crucial component of fitness in many organisms, yet the physiological regulation of defensive toxin synthesis is poorly understood, especially in vertebrates. Bufadienolides, the main defensive compounds of toads, are toxic to many predators and other natural enemies, and their synthesis can be upregulated by stressors, including predation risk, high conspecific density, and pollutants. Thus, higher toxin content may be the consequence of a general endocrine stress response in toads. Therefore, we hypothesized that bufadienolide synthesis may be stimulated by elevated levels of corticosterone (CORT), the main glucocorticoid hormone of amphibians, or by upstream regulators that stimulate CORT production. To test these alternatives, we treated common toad tadpoles with exogenous CORT (exoCORT) or metyrapone (MTP, a CORT-synthesis inhibitor that stimulates upstream regulators of CORT by negative feedback) in the presence or absence of predation cues for 2 or 6 days, and subsequently measured their CORT release rates and bufadienolide content. We found that CORT release rates were elevated by exoCORT, and to a lesser extent also by MTP, regardless of treatment length. Bufadienolide content was significantly decreased by treatment with exoCORT for 6 days but was unaffected by exposure to exoCORT for 2 days or to MTP for either 6 or 2 days. The presence or absence of predation cues affected neither CORT release rate nor bufadienolide content. Our results suggest that changes in bufadienolide synthesis in response to environmental challenges are not driven by CORT but may rather be regulated by upstream hormones of the stress response.

Heart Rate Variability as a Translational Dynamic Biomarker of Altered Autonomic Function in Health and Psychiatric Disease

The autonomic nervous system (ANS) is responsible for the precise regulation of tissue functions and organs and, thus, is crucial for optimal stress reactivity, adaptive responses and health in basic and challenged states (survival). The fine-tuning of central ANS activity relies on the internal central autonomic regulation system of the central autonomic network (CAN), while the peripheral activity relies mainly on the two main and interdependent peripheral ANS tracts, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). In disease, autonomic imbalance is associated with decreased dynamic adaptability and increased morbidity and mortality. Acute or prolonged autonomic dysregulation, as observed in stress-related disorders, affects CAN core centers, thereby altering downstream peripheral ANS function. One of the best established and most widely used non-invasive methods for the quantitative assessment of ANS activity is the computerized analysis of heart rate variability (HRV). HRV, which is determined by different methods from those used to determine the fluctuation of instantaneous heart rate (HR), has been used in many studies as a powerful index of autonomic (re)activity and an indicator of cardiac risk and ageing. Psychiatric patients regularly show altered autonomic function with increased HR, reduced HRV and blunted diurnal/circadian changes compared to the healthy state. The aim of this article is to provide basic knowledge on ANS function and (re)activity assessment and, thus, to support a much broader use of HRV as a valid, transdiagnostic and fully translational dynamic biomarker of stress system sensitivity and vulnerability to stress-related disorders in neuroscience research and clinical psychiatric practice. In particular, we review the functional levels of central and peripheral ANS control, the main neurobiophysiologic theoretical models (e.g., polyvagal theory, neurovisceral integration model), the precise autonomic influence on cardiac function and the definition and main aspects of HRV and its different measures (i.e., time, frequency and nonlinear domains). We also provide recommendations for the proper use of electrocardiogram recordings for HRV assessment in clinical and research settings and highlight pathophysiological, clinical and research implications for a better functional understanding of the neural and molecular mechanisms underlying healthy and malfunctioning brain-heart interactions in individual stress reactivity and psychiatric disorders.

Measuring resilience and stress during pregnancy and its relation to vulnerability and pregnancy outcomes in a nulliparous cohort study

BACKGROUND

Resilience reflects coping with pregnancy-specific stress, including physiological adaptations of the maternal organism or factors arising from the socioeconomic context, such as low income, domestic violence, drug and alcohol use, lack of a support network and other vulnerability characteristics. Resilience is a dynamic characteristic that should be comparatively evaluated within a specific context; its association with perceived stress and social vulnerability during pregnancy is still not fully understood. This study aimed at exploring maternal resilience, perceived stress and social vulnerability during pregnancy and its associated factors and outcomes.

METHODS

Prospective multicenter cohort study of nulliparous women in Brazil determining resilience (Resilience Scale; RS) and stress (Perceived Stress Scale; PSS) at 28 weeks of gestation (± 1 week). Resilience and stress scores were compared according to sociodemographic characteristics related to maternal/perinatal outcomes and social vulnerability, defined as having low level of education, being adolescent, without a partner or ethnicity other than white.

RESULTS

We included 383 women who completed the RS and PSS instruments. Most women showed low resilience scores (median: 124.0; IQR 98-143). Women with a low resilience score (RS < 125) were more likely from the Northeast region, adolescents, other than whites, did not study or work, had a low level of education, low family income and received public antenatal care. Higher scores of perceived stress were shown in the Northeast, other than whites, at low levels of education, low annual family income and public antenatal care. Pregnant women with low resilience scores (n = 198) had higher perceived stress scores (median = 28) and at least one vulnerability criterion (n = 181; 91.4%).

CONCLUSION

Our results reinforce the role of resilience in protecting women from vulnerability and perceived stress. It may prevent complications and build a positive experience during pregnancy.

Role of Hormones and the Potential Impact of Multiple Stresses on Infertility

Infertility has a remarkable global impact affecting approximately about 48 million couples worldwide. One of the most contended concerns in reproductive biology is the prospective influence of psychological stress on pregnancy rates. Individuals struggling to conceive face a stupendous amount of emotional turbulence and have a greater risk for psychological vulnerability. Both stress and infertility reinforce the impact of each other; hence, there exists a reciprocal relationship. Stress may be the major contributor to subsequent infertility. Infertility treatments may enhance stress levels as well as reduce treatment outcomes. The biological mechanisms that interlink stress and infertility are the outcome of the hormonal actions at the brain level, where they stimulate or suppress the hypothalamic-pituitary-adrenal axis (HPA) and have a potential influence on the secretion of the respective hormone by the reproductive organs and the pregnancy outcomes. Sex hormones play an essential role in reproductive biology as well as in general physiology where they generate the cycle and provide a potential environment for pregnancy. This article reviews the impact of stress on reproductive rates and the implications of sex hormones on infertility. Additionally, it suggests strategies to overcome the stress conditions and the scenarios that may lead to stress.

Measuring short-term changes in stress-associated salivary analytes in free-ranging Japanese macaques (Macaca fuscata)

Monitoring short-term changes of endocrine responses in non-human primates living in wild populations is a challenge. Saliva contains enzymes, steroids, and various analytes that can be broadly useful for helping us understand physiological responses to social and environmental sources of stress as well as other compromises to an individual's health homeostasis. Salivary alpha-amylase and salivary cortisol are known to respond rapidly to stress, which can allow us to use these analytes to monitor stress on a time scale of minutes. We developed a non-invasive methodology for the collection of saliva and verified its applicability by conducting short-term interval sampling of focal individuals under varying social conditions in a group of semi-provisioned free-ranging Japanese macaques (Macaca fuscata) living endemically on the island of Koshima, Miyazaki prefecture, Japan. Monkeys were habituated to sampling by using ingestive attractants applied to cotton ropes. Their receptivity to chewing on the saliva sampling material provided and chewing time was recorded ad libitum during the initial habituation period of the troop to the sampling procedure. Focal animal behavior observations were conducted in conjunction with saliva sampling. Salivary analytes associated with stress, alpha-amylase and cortisol, were measured via enzyme immunoassay. Short-term changes in salivary alpha-amylase and salivary cortisol were examined in relation to short-term changes in social behavior, in particular aggression or grooming. We tested flow-rate effects in both analytes and found strong correlations between original sample results and their respective flow-rate transformed equivalents. Additionally, temperature effects on samples were tested and both analytes showed nearly the same values when stored at - 20, 4, and 30 °C conditions for 6 h; important information expected to facilitate future sampling in field conditions where freezer storage is uncertain. Our study shows that saliva can be repeatedly sampled non-invasively to investigate short-term changes in stress-associated markers in free-ranging Japanese macaques.

Salinity and temperature affect the symbiont profile and host condition of Florida USA blue crabs Callinectes sapidus

Subtropical Florida blue crabs, Callinectes sapidus, exhibit differing life history traits compared to their temperate counterparts, likely influencing symbiont infection dynamics. Little information exists for Florida C. sapidus symbiont profiles, their distribution among various habitats, and influence on crab condition. Using histopathology, genomics, and transmission electron microscopy, we describe the first symbiont profiles for Florida C. sapidus occupying freshwater to marine habitats. Twelve symbiont groups were identified from 409 crabs including ciliophorans, digenean, microsporidian, Haplosporidia, Hematodinium sp., Nematoda, filamentous bacteria, gregarine, Callinectes sapidus nudivirus, Octolasmis sp., Cambarincola sp., and putative microcell. Overall, 78% of C. sapidus were documented with one or more symbiont groups demonstrating high infection rates in wild populations. Environmental variables water temperature and salinity explained 48% of the variation in symbiont groups among Florida habitats, and salinity was positively correlated with C. sapidus symbiont diversity. This suggests freshwater C. sapidus possess fewer symbionts and represent healthier individuals compared to saltwater populations. Crab condition was examined using the reflex action mortality predictor (RAMP) to determine if reflex impairment could be linked to symbiont prevalence. Symbionts were found positively correlated with crab condition, and impaired crabs were more likely to host symbionts, demonstrating symbiont inclusion may boost predictive ability of the RAMP application. The microsporidian symbiont group had a particularly strong effect on C. sapidus reflex response, and impairment was on average 1.57 times higher compared to all other symbiont groups. Our findings demonstrate the importance of considering full symbiont profiles and their associations with a spatially and temporally variable environment to fully assess C. sapidus population health.

Acute Social Stress Influences Moral Decision-Making Under Different Social Distances in Young Healthy Men

Acute social stress has been shown to influence social decision-making. This study aimed to examine how social distance modulates the influence of acute social stress on young male moral decision-making. Sixty healthy male college students were randomly divided to be exposed to the Trier Social Stress Test (TSST) or a placebo version of the TSST (P-TSST) before they performed moral decision-making tasks. The results showed that participants under acute social stress showed obvious increases in subjective stress perception, negative affect, salivary cortisol, and alpha-amylase and made more altruistic choices for others compared to the control group. However, social distance regulates the promotion of this acute social stress, with the promotion effect being stronger in socially distant others. Furthermore, the interpersonal order difference of different social distances in altruistic decisions is smaller in low-conflict dilemmas than in high-conflict dilemmas. In addition, an increase in salivary cortisol was positively correlated with altruistic choices toward both acquaintances and strangers, whereas an increase in salivary alpha-amylase was only positively correlated with altruistic choices toward friends. The results suggest that social distance modulates the promotion of acute social stress on moral decision-making, which might stem from the divergent effects of cortisol and alpha-amylase.

Skin Cortisol and Acoustic Activity: Potential Tools to Evaluate Stress and Welfare in Captive Cetaceans

As people's focus broadens from animals on farms to zoos and aquaria, the field of welfare science and the public's concern for animal welfare continue to grow. In captive animals, stress and its causes are topics of interest in welfare issues, and the identification of an objective method that can be used to assess animals' stress as a physiological state is essential. Both behavioral and physiological parameters can be used as indicators in order to assess animal stress quantitatively. To validate this approach, acoustic activity and the sloughed scrape skin cortisol concentration were used to evaluate the animal welfare of captive beluga whales (Delphinapterus leucas). The acoustic activity (5 min at 10:00 am) of three captive D. leucas was routinely recorded by a transducer and analyzed using audio editing software. The calls were separated into three main categories: whistles, pulses, and combo calls. The sloughed scrape skin samples were collected non-invasively once a week from all three animals' fluke and/or flipper. Cortisol was extracted using a modified skin steroid extraction technique, and detected via commercially available enzyme immunoassays. The results showed that the cortisol concentration increased by varying levels when the whales encountered the same event. In addition, the number and distribution of the calls changed along with the events. This indicated that the changes in the cortisol concentration and acoustic behavior may have reflected the fluctuations in the environment and body condition. Therefore, the scrape cortisol measurement and acoustic recordings could be used to monitor stress levels in captive beluga whales. We recommend that aquaria consider incorporating skin scrape cortisol and acoustic activity monitoring into their standards for animal welfare.

Environmental change or choice during early rearing improves behavioural adaptability in laying hen chicks

Laying hens are typically moved to a novel environment after rearing, requiring adaptability to cope with change. We hypothesized that the standard rearing of laying hen chicks, in non-changing environments with limited choices (a single variant of each resource), impairs their ability to learn new routines, use new equipment and exploit new resources. On the contrary, rearing in a changing environment that also offers a choice of resource variants could better prepare chicks for the unexpected. To explore this hypothesis, environmental change and choice were manipulated in a 2 × 2 factorial experiment. Compared to standard rearing, greater change during early rearing, through repeatedly swapping litter and perch types, reduced initial freezing when exposed to a novel environment suggesting a lower fear response. Greater choice during rearing, through simultaneous access to multiple litter and perch types, resulted in shorter latencies to solve a detour task, more movement in novel environments and less spatial clustering, suggesting improved spatial skills and higher exploration. However, combining both change and choice did not generally result in greater improvement relative to providing one or the other alone. We conclude that environmental change and choice during rearing have different positive but non-synergistic effects on later adaptability potential.

Repeated neonatal isoflurane exposure facilitated stress-related fear extinction impairment in male mice and was associated with ΔFosB accumulation in the basolateral amygdala and the hippocampal dentate gyrus

Volatile anesthetics elicit neurodevelopmental toxicity in rodents and primates and lead to more exaggerated anxiety-like behavior in response to future stress. Anxiety and fear are closely correlated and maladaptive fear-associated learning is regarded as the core mechanism underlying anxiety-related disorders. However, little is known about the interaction between early-life anesthetic exposure and future stress and the accompanying effect on fear-associated learning. In the present study, we evaluated the alterations in fear-associated learning (fear acquisition and extinction) occurring in mice receiving repeated neonatal isoflurane exposure and chronic variable stress (CVS) successively through a series of fear conditioning, fear reinforcing, and fear extinction paradigms. The corticosterone (CORT) response during CVS and the immunohistochemical levels of ΔFosB and c-Fos expression in the basolateral amygdala (BLA) and the hippocampal dentate gyrus (DG) after the extinction retrieval test were also investigated. The results showed that neonatal isoflurane exposure could increase CORT levels following the first diurnal CVS procedure, but not after completion of the whole CVS paradigm. Neonatal isoflurane exposure exerted a repressive effect on fear acquisition, in contrast to that seen with CVS. Neonatal isoflurane exposure and CVS both exerted suppressive effects on fear extinction and there was a significant synergy between them. Furthermore, neonatal isoflurane exposure facilitated CVS-mediated ΔFosB accumulation in the BLA and the hippocampal DG, which may have been responsible for c-Fos expression deficits and fear extinction impairment. Collectively, these findings contribute to the understanding of the interaction between early-life anesthetic exposure and future stress, as well as the accompanying behavioral alterations.

Exposure to COVID-19 and aggression: the mediating role of anxiety and the moderating role of rumination

The pandemic of COVID-19 is now posing a worldwide hazard to one's health. Exposure to COVID-19 may cause negative emotions like anxiety, which is one of recognized risk factors for aggressive behaviors. This study looked into the effect of exposure to COVID-19 on aggression and how anxiety may act as a mediating factor, as well as lastly how rumination could moderate a variety of indirect paths during the epidemic of COVID-19. According to the current study's findings, which included a sizable sample of Chinese college students (N = 1,518), being exposed to COVID-19 showed a positive connection with aggression and anxiety, as well as rumination. These findings clarify the role that mediators play in the relationship between anxiety and exposure to COVID-19. The results are also helpful for personalizing treatments and putting preventative measures in place to decrease the aggression brought on by exposure to COVID-19. It is explored how lowering rumination and anxiety may be useful in the context of COVID-19 to lessen the psychopathological effects of the condition.

The power of a touch: Regular touchscreen training but not its termination affects hormones and behavior in mice

Touchscreen-based procedures are increasingly used in experimental animal research. They not only represent a promising approach for translational research, but have also been highlighted as a powerful tool to reduce potential experimenter effects in animal studies. However, to prepare the animals for a touchscreen-based test, an often time-consuming training phase is required that has itself been shown to cause increased adrenocortical activity and anxiety-like behavior in mice. While these findings point at a potentially negative effect of touchscreen training at first glance, results have also been discussed in light of an enriching effect of touchscreen training. The aim of the present study was therefore to shed more light on recently reported touchscreen training effects, with a particular focus on the termination of the training routine. Specifically, we investigated whether the termination of regular touchscreen training could constitute a loss of enrichment for mice. Thus, we assessed fecal corticosterone metabolites (FCMs), exploratory-, anxiety-like and home cage behavior in touchscreen-trained mice in comparison to food restricted and ad libitum fed mice, as a restricted diet is an integral part of the training process. Furthermore, we compared these parameters between mice that were continuously trained and mice whose training was terminated 2 weeks earlier. Our results confirm previous findings showing that a mild food restriction increases the animals' exploratory behavior and shifts their activity rhythm. Moreover, touchscreen training was found to increase FCM levels and anxiety-like behavior of the mice. However, no effect of the termination of touchscreen training could be detected, a finding which contradicts the enrichment loss hypothesis. Therefore, we discuss two alternative explanations for the findings. Yet, the current state of knowledge is not sufficient to draw final conclusions at this stage. In compliance with the refinement endeavors for laboratory animals, further research should assess the severity of touchscreen procedures to ensure a responsible and well-founded use of animals for experimental purposes.

Early life stress, depression and epigenetics

Different factors are essential in increasing the vulnerability to psychiatric disorders, such as genetics. Among these factors, early life stress (ELS), including sexual, physical, emotional abuse, and emotional and physical neglect, enhances the odds of having menial conditions throughout life. Exhaustive research has shown that ELS leads to physiological changes, such as alteration in the HPA axis. During the most critical development period (childhood and adolescence), these changes increase the risk of having child-onset psychiatric disorders. Furthermore, research has suggested a relationship between early life stress and depression, particularly more prolonged episodes of depression with treatment-resistant outcomes. Molecular studies indicate that, in general, the hereditary character of psychiatric disorders is polygenic, multifactorial and highly complex, with innumerable low-effect genetic variants interacting with each other. However, whether there are independent effects among subtypes of ELS remains unclear. This article provides an overview of the interplay of epigenetics, the HPA axis, early life stress and the development of depression. Advances in our knowledge of epigenetics in the context of early life stress and depression provide a new understanding of the genetic influence on psychopathology. Furthermore, they could lead to identifying new targets for clinical intervention.

Prenatal stress modulates HPA axis homeostasis of offspring through dentate TERT independently of glucocorticoids receptor

In response to stressful events, the hypothalamic-pituitary-adrenal (HPA) axis is activated, and consequently glucocorticoids are released by the adrenal gland into the blood circulation. A large body of research has illustrated that excessive glucocorticoids in the hippocampus exerts negative feedback regulation of the HPA axis through glucocorticoid receptor (GR), which is critical for the homeostasis of the HPA axis. Maternal prenatal stress causes dysfunction of the HPA axis feedback mechanism in their offspring in adulthood. Here we report that telomerase reverse transcriptase (TERT) gene knockout causes hyperactivity of the HPA axis without hippocampal GR deficiency. We found that the level of TERT in the dentate gyrus (DG) of the hippocampus during the developmental stage determines the responses of the HPA axis to stressful events in adulthood through modulating the excitability of the dentate granular cells (DGCs) rather than the expression of GR. Our study also suggests that the prenatal high level of glucocorticoids exposure-induced hypomethylation at Chr13:73764526 in the first exon of mouse Tert gene accounted for TERT deficiency in the DG and HPA axis abnormality in the adult offspring. This study reveals a novel GR-independent mechanism underlying prenatal stress-associated HPA axis impairment, providing a new angle for understanding the mechanisms for maintaining HPA axis homeostasis.

Sex effects in the interaction of acute stress and pain perception

ABSTRACT

A reciprocity between the stress and the pain system is recognized; however, the manner by which sex affects this reciprocity is unclear. Understanding the interactions of stress, pain, and sex may shed light on the apparent women's vulnerability to chronic pain, which often coexists with increased distress, and to affective disorders, which often coexist with chronic pain. The study's aim was to examine the effect of acute, validated, psychosocial stress on pain perception and modulation of women and men in a controlled manner. Participants were 82 women and 66 men. Heat-pain threshold, heat-pain tolerance, and pain modulation by temporal summation of pain (TSP), and pain adaptation were measured before and after exposure to the Montreal Imaging Stress Task (MIST) or to a sham task. The stress response was verified by perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. A significant stress response was obtained by the MIST among both sexes; however, women displayed a greater increase in perceived distress, and men displayed a greater increase in cortisol. Among women, TSP decreased and pain adaptation increased following the MIST, responses that were predicted by perceived distress levels. Among men, TSP increased following the MIST but was not predicted by the stress variables. In conclusion, acute stress manipulation seems to differentially affect both stress and pain responses of women and men: women exhibited stress-induced antinociception and men exhibited stress-induced pronociception. Higher perceived stress levels among women may trigger a temporary increase in pain inhibition mechanisms to serve evolutionary purposes.

Modeling integrated stress, sleep, fear and neuroimmune responses: Relevance for understanding trauma and stress-related disorders

Sleep and stress have complex interactions that are implicated in both physical diseases and psychiatric disorders. These interactions can be modulated by learning and memory, and involve additional interactions with the neuroimmune system. In this paper, we propose that stressful challenges induce integrated responses across multiple systems that can vary depending on situational variables in which the initial stress was experienced, and with the ability of the individual to cope with stress- and fear-inducing challenges. Differences in coping may involve differences in resilience and vulnerability and/or whether the stressful context allows adaptive learning and responses. We provide data demonstrating both common (corticosterone, SIH and fear behaviors) and distinguishing (sleep and neuroimmune) responses that are associated with an individual's ability to respond and relative resilience and vulnerability. We discuss neurocircuitry regulating integrated stress, sleep, neuroimmune and fear responses, and show that responses can be modulated at the neural level. Finally, we discuss factors that need to be considered in models of integrated stress responses and their relevance for understanding stress-related disorders in humans.

Measuring the Effectiveness of a Multicomponent Program to Manage Academic Stress through a Resilience to Stress Index

In this work, we evaluate the effectiveness of a multicomponent program that includes psychoeducation in academic stress, mindfulness training, and biofeedback-assisted mindfulness, while enhancing the Resilience to Stress Index (RSI) of students through the control of autonomic recovery from psychological stress. Participants are university students enrolled in a program of excellence and are granted an academic scholarship. The dataset consists of an intentional sample of 38 undergraduate students with high academic performance, 71% (27) women, 29% (11) men, and 0% (0) non-binary, with an average age of 20 years. The group belongs to the "Leaders of Tomorrow" scholarship program from Tecnológico de Monterrey University, in Mexico. The program is structured in 16 individual sessions during an eight-week period, divided into three phases: pre-test evaluation, training program, and post-test evaluation. During the evaluation test, an assessment of the psychophysiological stress profile is performed while the participants undergo a stress test; it includes simultaneous recording of skin conductance, breathing rate, blood volume pulse, heart rate, and heart rate variability. Based on the pre-test and post-test psychophysiological variables, an RSI is computed under the assumption that changes in physiological signals due to stress can be compared against a calibration stage. The results show that approximately 66% of the participants improved their academic stress management after the multicomponent intervention program. A Welch's t-test showed a difference in mean RSI scores (t = -2.30, p = 0.025) between the pre-test and post-test phases. Our findings show that the multicomponent program promoted positive changes in the RSI and in the management of the psychophysiological responses to academic stress.

Effect of Acute Psychological Stress on Speed Perception: An Event-Related Potential Study

The present study tested the intrinsic ERP features of the effects of acute psychological stress on speed perception. A mental arithmetic task was used to induce acute psychological stress, and the light spot task was used to evaluate speed perception. Compared with judgments in the constant speed and uniform acceleration motion, judgments in the uniform deceleration motion were made more quickly and with higher accuracy; attention control was higher and peaked later; and there was longer N2 peak latency, larger N2 peak amplitude, and lower mean amplitude of the late negative slow wave (SW). Under stress, the reaction time was significantly shorter. The N2 peak amplitude and SW mean amplitude were significantly higher, attention control was higher and appeared earlier, and there was a greater investment of cognitive resources. The type of movement and evoked stress also interacted to predict behavioral and ERP measures. Under acute stress, judgments made in the uniform deceleration motion condition elicited lower N2 peak latency, higher attention control, and later peak attention. The results suggest that judgments of the speed of decelerating motion require a lower investment of cognitive resources than judgments of other kinds of motion, especially under acute stress. These findings are best interpreted in terms of the interaction of arousal and attention.

Work stressors and their controllability: Content analysis of employee perceptions of hindrances to the flow of work in the health care sector

High levels of work stress are prevalent today, and the underlying working conditions need to be tackled urgently. In this study, our aim was to identify the range of factors that employees themselves perceive as hindrances to the flow of work, that is, hindrance stressors. We analysed the open-ended questionnaire responses of 4766 employees working in the health care sector using semi-automated content analysis. We then used more detailed conventional content analysis to compare the responses of the groups that reported high (n = 1388) and low (n = 833) levels of subjective stress. Finally, we interpreted and categorised the stressors raised by the respondents from the viewpoint of controllability, to shed light on where to target interventions. The main hindrance stressors reflected inadequate staffing, work overload, time pressure, and management-related issues, of which the responses revealed concrete examples. Interruptions and problems related to cooperation and instructions were also commonly mentioned. The respondents in the high stress group emphasised work overload and issues related to management and clients. Our results suggest that the major hindrances to daily work are beyond employees' control and require decisions and resources at the level of supervisors, managers, directors, and policymakers. Future studies on work stress should explore the controllability of common stressors in more detail and include the appraisal of controllability in explanatory models. Avoiding overemphasis of psychological coping and instead targeting harmful working conditions and the organisational actors who can influence these could make workplace stress management interventions more effective.

The influence of manual semen collection in male trained dogs (Canis familiaris), in the presence or absence of a female in estrus, on the concentrations of cortisol, oxytocin, prolactin and testosterone

Sex pheromones are chemical substances secreted into the environment that affect the physiology and behavior of recipients. Females use these compounds during oestrus to attract males, which leads to attempts of mating. This study evaluates the influence of manual semen collection in male dogs, in the presence or absence of a female in estrus, on the blood concentrations of cortisol (CRT), oxytocin (OXT), prolactin (PRL) and testosterone (T), as hormones involved both in the physiology of reproduction and stress. Ten male dogs were used in Experiment 1 to measure the serum and plasma concentrations of the aforementioned hormones in the absence of semen collection. Subsequently in the same animals, the concentrations of these hormones were evaluated before and after semen collection in the presence (Exp. 2) or in absence of a female in estrus (Exp. 3). No significant changes in hormone concentration caused by the semen collection were found, either with, or without the presence of female in estrus. Obtained results suggest that the procedure of manual semen collection in dogs, probably due to its passive character, does not stimulate endocrine glands to secrete hormones, and the process of ejaculation is probably controlled by neural pathway. The lack of effect of semiochemical stimulation to the CRT, PRL, OXT and T level, could be caused by a short contact with female during semen collection. Further studies on involvement of the hormones during the process of natural mating, especially preceded by long courtships, similar to that observed under natural conditions, should shed a light on the physiology of mating and the connection between the endocrine system and semiochemical stimulation in dogs.

Ecological validity of social defeat stressors in mouse models of vulnerability and resilience

Laboratory mouse models offer opportunities to bridge the gap between basic neuroscience and applied stress research. Here we consider the ecological validity of social defeat stressors in mouse models of emotional vulnerability and resilience. Reports identified in PubMed from 1980 to 2020 are reviewed for the ecological validity of social defeat stressors, sex of subjects, and whether results are discussed in terms of vulnerability alone, resilience alone, or both vulnerability and resilience. Most of the 318 reviewed reports (95%) focus on males, and many reports (71%) discuss vulnerability and resilience. Limited ecological validity is associated with increased vulnerability and decreased resilience. Elements of limited ecological validity include frequent and repeated exposure to defeat stressors without opportunities to avoid or escape from unfamiliar conspecifics that are pre-screened and selected for aggressive behavior. These elements ensure defeat and may be required to induce vulnerability, but they are not representative of naturalistic conditions. Research aimed at establishing causality is needed to determine whether ecologically valid stressors build resilience in both sexes of mice.

Threat-induced alterations in cognition and associations with dysregulated behavior

Previous literature suggests that threat disrupts cognitive control, especially for those prone to engaging in dysregulated behaviors (i.e., maladaptive attempts at regulating stress). However, this relationship is not well understood and has yet to be directly examined. The current study extends previous literature by examining the link between individual differences in dysregulation and threat-related alterations in neurocognitive and behavioral indicators of cognitive control. Using a diverse community sample (N = 143), we recorded participants' brain activity during a flanker task under conditions of predictable, unpredictable, and no threat-of-shock. Findings revealed a nuanced relationship, whereby predictable threat, relative to unpredictable threat, was associated with larger N2 to flankers, perhaps at the expense of a reduced later P3. We also found a relationship between proneness toward dysregulated behaviors and threat-induced alterations of cognitive control, with those higher in dysregulation showing reduced conflict P3 differentiation and accuracy interference during threat vs. no threat conditions. This research expands what is known about how threat can modulate cognition in everyday life and linked it to dysregulated behaviors with high societal burden.

Awake and Sleep Bruxism Prevalence and Their Associated Psychological Factors in First-Year University Students: A Pre-Mid-Post COVID-19 Pandemic Comparison

There is a broad consensus accepting that psychological variables such as stress, anxiety, or depression play an important role in bruxism. The COVID-19 pandemic has led to an increase in stress, anxiety, and depression levels. The purpose of this study was to evaluate the impact of the COVID-19 pandemic on possible awake and sleep bruxism prevalence and on the psychological factors associated with bruxism, comparing pre-pandemic, pandemic/lockdown, and post-pandemic samples of first-year students. A total of 274 dentistry students from the Complutense University of Madrid participated in the study: 92 from 2018/2019 (pre-pandemic), 90 from 2020/2021 (pandemic), and 92 students from 2021/2022 (post-pandemic) academic years. The participants filled out a thorough battery of validated questionnaires evaluating bruxism and different psychological characteristics, such as anxiety, depression, somatization, personality, and stress coping styles. While sleep bruxism prevalence was significantly higher for the pandemic group, awake bruxism was smaller in comparison to pre-pandemic and post-pandemic groups. The post-pandemic group also presented higher levels of neuroticism and agreeableness personality traits, and positive reappraisal than the pre-pandemic group, with the pandemic group somewhere in between. Additionally, both the pandemic and post-pandemic group showed higher levels of depression and acceptance/resignation coping styles than the pre-pandemic group. Thus, among the three groups of students, the post-pandemic group was the one that showed a larger effect of the pandemic situation in their psychological variables, presenting higher levels of anxiety (state and trait), depression, acceptation/resignation coping style, higher neuroticism (emotional instability trait), and lower agreeableness trait. Nonetheless, the increase of positive reappraisal in the post-pandemic group (an adaptive coping stress style) might be also a sign of recovery. The higher sleep bruxism for the pandemic group might be related to the pandemic situation and lockdown, passively suffered, possibly promoting feelings of impotency, increased levels of depression and acceptance/resignation (normally considered a passive/maladaptive coping style), while acute stressful situations derived from daily personal social interactions might have increased anxiety levels and induced higher levels of awake bruxism observed in both the pre-pandemic and post-pandemic groups. However, further research, including larger and more representative samples, is needed to confirm this possible relationship.

Heat Shock Protein Response to Stress in Poultry: A Review

Compared to other animal species, production has dramatically increased in the poultry sector. However, in intensive production systems, poultry are subjected to stress conditions that may compromise their well-being. Much like other living organisms, poultry respond to various stressors by synthesising a group of evolutionarily conserved polypeptides named heat shock proteins (HSPs) to maintain homeostasis. These proteins, as chaperones, play a pivotal role in protecting animals against stress by re-establishing normal protein conformation and, thus, cellular homeostasis. In the last few decades, many advances have been made in ascertaining the HSP response to thermal and non-thermal stressors in poultry. The present review focuses on what is currently known about the HSP response to thermal and non-thermal stressors in poultry and discusses the factors that modulate its induction and regulatory mechanisms. The development of practical strategies to alleviate the detrimental effects of environmental stresses on poultry will benefit from detailed studies that describe the mechanisms of stress resilience and enhance our understanding of the nature of heat shock signalling proteins and gene expression.

Effects of castration and sterilization on baseline and response levels of cortisol-A case study in male guinea pigs

An uncontrolled reproduction of animals in human hands should be avoided. To meet this goal, animals are widely castrated, i.e., the gonads are completely removed. Since the gonads are the most important source of sex hormones, this is a serious intervention in the entire endocrine system of an organism. Sterilization is a much less invasive procedure. Thus, it could have advantages over castration. Therefore, the overall aim of this study was to analyze the effect of castration vs. sterilization on the release of glucocorticoids, i.e., an important indicator for welfare. Taking domestic guinea pigs as a model system, we studied baseline and response cortisol values (cortisol is the main glucocorticoid in guinea pigs) in castrated, sterilized, sham-operated and intact males and baseline values in their cohoused females. Whereas baseline values of males did not differ between the groups, castrated males showed significantly higher cortisol response levels than intact, sham-operated and sterilized males. Females housed with castrated, sterilized, sham-operated or intact males did not differ in their cortisol concentrations, neither shortly after being placed with the respective male or after being co-housed for several weeks. Overall, the results support the hypothesis that castrated males exhibited a higher cortisol responsiveness during acute challenge which could point to a generalized impaired welfare of castrated males in comparison to intact, sham-operated and sterilized males. Our results provide first evidence for a potential negative impact of castration on the animals' welfare, while at the same time pointing toward sterilization representing a less invasive, promising alternative. Therefore, the results may stimulate future research on this topic to further detect potential welfare-related side effects of castration.

Blood transcriptomic differences in the immune response under stressful environmental according to stocking density in pigs

The implementation of animal welfare in the pig industry is becoming a global trend, and welfare can be improved through livestock management. In modern and intensive farming systems, it has become important to find a reasonable compromise between stocking density and productivity. The simultaneous detection of behavioral and physiological parameters is helpful when considering welfare levels for stocking density. This study aimed to confirm the effect of stocking density through transcriptome linkage. A comparison of three groups according to stocking density (low density, eight pigs and 1.0 m2 per head; normal density, eight pigs and 0.8 m2 per head; and high density, eight pigs and 0.6 m2 per head) was performed, and their transcriptomic changes were observed using the RNA-Seq method. Differentially expressed genes were identified for each comparison group (low density vs. normal density, 95 upregulated genes and 112 downregulated genes; high density vs. normal density, 133 upregulated genes and 217 downregulated genes; and high density vs. low density, 245 upregulated genes and 237 downregulated genes). Biological mechanisms according to stocking density were identified through functional annotation. T-cell differentiation and immune disease pathway enriched in the high-density group caused immune imbalance through dysregulated T-cell signaling. Moreover, oxidative stress, together with DNA damage, can lead to high susceptibility to disease. Our study confirmed the biological mechanisms through immunological expression patterns according to stocking density. The study results are expected to provide comprehensive insight into systematic operation strategies considering stocking density and biomarkers for use in welfare evaluation.

Stress in wildlife: comparison of the stress response among domestic, captive, and free-ranging animals

The stress response, which involves joint activity of the nervous and endocrine systems, is one of the basic adaptive mechanisms that ensures the survival of the individual. The activation of the sympathetic nervous system, the sympathetic-adrenal-medullary axis, and the hypothalamic-pituitary-adrenal axis enables organisms to respond to endogenous and exogenous challenges. Repeated short-term stress leads to long-term stress, which disrupts physiological homeostasis. Unlike domestic animals, wild animals are not protected from environmental and weather influences or treated for diseases. In addition, climate change, habitat fragmentation and loss, and urban stressors (such as light, noise and chemical pollution; xenobiotics; traffic; and buildings) affect individual wildlife and populations. In this review, we have attempted to depict the magnitude of the stress response in wildlife and related domestic animals as well as in captive and free-ranging animals. The intensity of the stress response can be estimated by determining the concentration of glucocorticoids in body fluids, tissues, and excreta. A comparison of results from different studies suggests that domestic animals have lower fecal and hair glucocorticoid concentrations than related wild animals. Additionally, fecal and hair glucocorticoid concentrations in captive animals are higher than in free-ranging animals of the same species. As there are limited data on this topic, we cannot draw definitive conclusions about glucocorticoid concentration and stress response. Further studies are needed to clarify these issues.

The multiple roles of life stress in metabolic disorders

The activation of stress-related neuroendocrine systems helps to maintain homeostasis, but excessive stress can damage body functions. We review current evidence from basic sciences and epidemiology linking stress to the development and progression of metabolic disorders throughout life. Findings from rodents demonstrate that stress can affect features of metabolic dysfunction, such as insulin resistance, glucose and lipid homeostasis, as well as ageing processes such as cellular senescence and telomere length shortening. In human studies, stressors in the home, workplace and neighbourhood are associated with accelerated ageing and metabolic and immune alterations, both directly and indirectly via behavioural risks. The likelihood of developing clinical conditions, such as diabetes mellitus and hepatic steatosis is increased in individuals with adverse childhood experiences or long-term (years) or severe stress at work or in private life. The increased risk of metabolic disorders is often associated with other stress-related conditions, such as mental health disorders, cardiovascular disease and increased susceptibility to infections. Equally, stress can worsen prognosis in metabolic diseases. As favourable modifications in stressors are associated with reductions in incidence of metabolic disorders, further investigation of the therapeutic value of targeting stress in personalized medicine is warranted.