Stressors, stress, and neuroendocrine integration of the adaptive response. The 1997 Hans Selye Memorial Lecture

The role of cortisol in the acute immune regulation of channel catfish (Ictalurus punctatus) spleen stimulated by Aeromonas hydrophila

Channel catfish (Ictalurus punctatus), a significant aquaculture species, occupies a prominent position in the aquaculture industry due to its rapid growth, excellent adaptability, and economic value; however, the hemorrhagic disease caused by Aeromonas hydrophila has had a substantial impact on its cultivation. Researches have indicated that cortisol, the main stress hormone, is essential for regulating immune responses. Therefore, in this study, the immune regulatory effects of cortisol on the spleen tissue under Aeromonas hydrophila stimulation were analyzed. Through transcriptomic (RNA-seq) analysis, we identified 167 differentially expressed genes (DEGs) regulated by cortisol. The KEGG enrichment analysis indicated that the DEGs were predominantly associated with various biological pathways, including antigen processing and presentation, bladder cancer, autophagy in animals, lipid metabolism, and atherosclerosis. Protein-protein interaction network analysis further indicated that these DEGs participate in key signaling pathways, including HIF, JAK-STAT, and NF-KB. Our findings demonstrate that cortisol exerts an immunoregulatory effect by modulating these key signaling pathways in the spleen tissue infected with Aeromonas hydrophila, which is of significant importance for understanding the mechanism of cortisol in fish immune responses.

Social context prevents heat hormetic effects against mutagens during fish development

Since stress can be transmitted to congeners via social metabolites, it is paramount to understand how the social context of abiotic stress influences aquatic organisms' responses to global changes. Here, we integrated the transcriptomic and phenotypic responses of zebrafish embryos to a UV damage/repair assay following scenarios of heat stress, its social context and their combination. Heat stress preceding UV exposure had a hormetic effect through the cellular stress response and DNA repair, rescuing and/or protecting embryos from UV damage. However, experiencing heat stress within a social context negated this molecular hormetic effect and lowered larval fitness. We discuss the molecular basis of interindividual chemical transmission within animal groups as another layer of complexity to organisms' responses to environmental stressors.

Hypothalamic-pituitary-adrenal axis functioning in offspring of parents with a major affective disorder: a meta-analytic review

Because the offspring of parents with an affective disorder (OAD) are at high risk for developing mental disorders, and persons with an affective disorder (AD) show dysfunctional hypothalamic-pituitary-adrenal (HPA) axis activity, changes in HPA functioning in OAD might be an etiological risk factor that precedes the development of ADs. The primary aim of the meta-analysis was to quantitatively summarize the existing data on different indices of diurnal cortisol in the OAD. The secondary aim was to explore potential moderators of this relation. Following PRISMA guidelines, we included 26 studies (3052 offspring) on diurnal cortisol in our meta-analysis after an initial screening of 3408 articles. Intercept-only and meta-regression models were computed using the robust variance estimation method. Analyses examining mean cortisol levels at discrete timepoints, total cortisol output, and the cortisol rise in response to awakening (CAR) were conducted separately. The results demonstrated that the OAD had higher mean levels of cortisol at different timepoints throughout the day compared to controls (Hedge's g = 0.21). There was evidence of publication bias in studies examining CAR, such that effect sizes were positively biased. The present findings are consistent with a meta-analysis showing elevated cortisol in youth having an AD. Notable limitations across studies include the method of cortisol measurement and assessment of ADs. Altogether, these results highlight the fact that increased cortisol levels may act as a potential neuroendocrine antecedent and/or risk factor for the development of ADs among high risk youth.

Patterns of stress-related change in salivary alpha-amylase and cortisol among young children: Associations with maternal psychosocial risk factors

Our understanding of associations between family-level risk factors and children's stress physiology is largely derived from studies that apply "mean-based" rather than "person-level" approaches. In this study, we employed group-based trajectory modeling, a person-centered approach, to identify children with similar patterns of stress-related sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis activation, and explored associations between these patterns and maternal psychosocial risk. Participants were five-year-old children (N=147; 52 % female; 62 % Black/African American) and their mothers. Children's saliva was sampled four times during a series of emotional stressor tasks and later assayed for sAA and cortisol, indexing SNS and HPA activity, respectively. Mothers reported their depressive and anxiety symptoms, parenting stress, financial stress, and income. Results revealed two task-related patterns of change for sAA (Low-Stable vs. High-Increasing) and cortisol (Low-Stable vs. High-Decreasing) concentrations. Children from families with lower income were more likely to exhibit the High-Increasing SNS pattern, [OR=0.78, 95 % CI (0.64, 0.95)], and children of mothers reporting more anxiety symptoms [OR=1.06, 95 % CI (1.00, 1.12)] and more parenting stress [OR=1.04, 95 % CI (1.00, 1.07)] were more likely to show the High-Decreasing HPA pattern. Implications of this person-centered approach and findings for advancing our understanding of associations between family-level risk factors and children's stress physiology are discussed.

An optimized whole-body corticosteroid hormones quantification method by LC-MS/MS for assessing stress levels in European glass eels (Anguilla anguilla)

The European eel (Anguilla anguilla) juvenile stage exhibits facultative estuarine migration. The causes of this behavior are yet unknown but it may have an impact on the population's fate by altering the sex ratio of the population. Recent studies have highlighted potential stress-related issues in glass eels settling in estuaries but studying stress response in small organisms requires sensitive, accurate and precise analytical methods. The aims of the present study are (i) to develop a whole-body Liquid Chromatography-Mass Spectrometry (LC-MS/MS) method for the simultaneous determination of several stress hormones in low-body mass fish; (ii) to apply this method to glass eels to study their responses to acute stress (iii) to test the effect of anxiolytics (diazepam) on these responses. Our results showed that enhanced LC-MS/MS analysis reduced detection limits and improved accuracy and precision for the quantification at the individual level. Following an acute stress, cortisol concentration significantly increased in glass eels and a 15 h diazepam exposure significantly reduced cortisol levels highlighting a marked anxiolytic effect on this species.

Early-life challenge enhances cortisol regulation in zebrafish larvae

The hypothalamic-pituitary-adrenal (HPA) axis in mammals and the hypothalamic-pituitary-interrenal (HPI) axis in fish are open systems that adapt to the environment during development. Little is known about how this adaptation begins and regulates early stress responses. We used larval zebrafish to examine the impact of prolonged forced swimming at 5 days post-fertilization (dpf), termed early-life challenge (ELC), on cortisol responses, neuropeptide expression in the nucleus preopticus (NPO), and gene transcript levels. At 6 dpf, ELC-exposed larvae showed normal baseline cortisol but reduced reactivity to an initial stressor. Conversely, they showed increased reactivity to a second stressor within the 30-min refractory period, when cortisol responses are typically suppressed. ELC larvae had fewer corticotropin-releasing hormone (crh), arginine vasopressin (avp), and oxytocin (oxt)-positive cells in the NPO, with reduced crh and avp co-expression. Gene expression analysis revealed upregulation of genes related to cortisol metabolism (hsd11b2, cyp11c1), steroidogenesis (star), and stress modulation (crh, avp, oxt). These results suggest that early environmental challenge initiates adaptive plasticity in the HPI axis, tuning cortisol regulation to balance responsiveness and protection during repeated stress. Future studies should explore the broader physiological effects of prolonged forced swimming and its long-term impact on cortisol regulation and stress-related circuits.

A multisystem model for understanding stress and adaptation in ethnically and racially diverse youth

Contemporary biological and contextually based theoretical frameworks have conceptualized how stress exposure may influence adaptation in youth. However, nearly all of this scholarship neglects the role of specific contextual features and/or biological processes that are involved in ethnic-racial minority youth's responses and adaptation to sociocultural stressors. Drawing on the theoretical principles of the developmental psychopathology framework and contemporary models of stress and adaptation, this article proposes a new multisystem model that explains how multiple levels and systems within and outside of individual youth influence their sociocultural adaptation. We provide empirical evidence to support components of this multisystem model. We propose that research based on our new theoretical framework will capture the sociocultural experiences of ethnic-racial minority youth by centering processes that are relevant to their lived experiences, coping, and adjustment. In doing so, this model will inform psychosocial interventions focused on promoting healthy adaptation among ethnic and racial diverse youth. Finally, we offer recommendations to guide future research on stress and adaptation among ethnic and racial diverse youth, in particular, and developmental psychopathology more broadly.

Stress induces nucleobindin-1 mRNA and nesfatin-1-like peptide stimulates cortisol secretion in goldfish

Stress is a state of disrupted homeostasis triggered by physical or psychological stimuli that elicit adaptive responses at the molecular and cellular levels. In fish, the hypothalamus-pituitary-interrenal (HPI) axis mediates stress responses. Nesfatin-1 and a nesfatin-1-like peptide (NLP), derived from nucleobindin-1 (NUCB1), have been implicated in stress hormone regulation in mammals. This study investigated the cell-specific expression of NUCB1/NLP in HPI tissues and its effects on stress response in goldfish (Carassius auratus). NUCB1 mRNA is abundant in the hypothalamus, pituitary, and several other peripheral tissues of goldfish. NUCB1/NLP-like immunoreactivity was found in the brain and pituitary, co-localized with corticotropin-releasing factor receptor 1 (CRF-R1) in the hypothalamus, and with adrenocorticotrophic hormone (ACTH) in the pituitary. In vivo netting and restraint stress increased nucb1 and crf-r1 mRNAs in the brain and acth mRNA in the pituitary, as determined by RT-qPCR. Intraperitoneal injection of NLP increased cortisol in circulation, crf-r1 mRNA in the brain and acth mRNA in the pituitary. These findings suggest that NUCB1/NLP is a new player in mediating the endocrine stress response of goldfish through the HPI axis.

Effects of Adverse Life History on Oxidative Stress and Cytokine Concentration in Domestic Dogs

Early-life stress has been well studied in humans and laboratory animals; however, the impacts of similar adversity on the welfare of domestic dogs has recently begun to be addressed. For example, associations between processes linked to mitochondrial function, such as oxidative stress (OS) and proinflammatory immune systems, have been under-researched. Yet, mitochondria are targets and mediators of stress pathologies. This study investigates the impact of early-life stress on OS and proinflammatory immune responses in shelter dogs compared to client-owned dogs. We measured OS markers, including total antioxidant capacity (TAC), lipid oxidative damage, catalase (CAT) activity, glutathione peroxidase (GPx) activity, and superoxide dismutase (SOD) concentration, as well as inflammatory cytokines IL-1β, IL-6, and TNF-α. Shelter dogs exhibited significantly higher lipid oxidative damage (p = 0.0265), lower CAT activity (p = 0.002), higher SOD concentration (p < 0.001), and increased IL-1β levels (p = 0.027) compared to client-owned dogs. Compared to client-owned dogs, shelter dogs showed increased OS and inflammation, suggesting higher susceptibility to zoonotic and chronic diseases.

Cortisol dynamics and GR-dependent feedback regulation in zebrafish larvae exposed to repeated stress

Zebrafish larvae show a rapid increase in cortisol in response to acute stressors, followed by a decline. While these responses are documented, both the duration of the refractory period to repeated stressors and the role of glucocorticoid receptors (GR) in specific phases of the glucocorticoid negative feedback are still being clarified. We explored these questions using water vortices as stressors, combined with GR blockage and measurements of whole-body cortisol in zebrafish larvae subjected to single and repeated stress protocols. Cortisol levels were elevated 10 min after stress onset and returned to baseline within 30-40 min, depending on the stressor strength. In response to homotypic stress, cortisol levels rose above baseline if the second stressor occurred 60 or 120 min after the first, but not with a 30-min interval. This suggests a rapid cortisol-mediated feedback loop with a refractory period of at least 30 min. Treatment with a GR blocker delayed the return to baseline and suppressed the refractory period, indicating GR-dependent early-phase feedback regulation. These findings are consistent with mammalian models and provide a framework for further analyses of early-life cortisol responses and feedback in zebrafish larvae, ideal for non-invasive imaging and high-throughput screening.

Women's experiences of sexual harassment in the retail clothing industry: a grounded theory study

Introduction

Sexual harassment is a significant problem in workplaces all over the world. Women's reactions to sexual harassment are influenced by various factors. The aim of the current study was to investigate how women respond sexual harassment in the retail clothing industry.

Methods

In-depth face-to-face interviews were conducted with 16 women aged 23-44 years (mean 29.18 years) employed for at least 3 years in clothes shops in Shiraz, Iran. A grounded theory approach was used to analysis the data and raise hypotheses.

Results

The main perpetrators of sexual harassment for female saleswomen were male customers. The women experienced conflict-induced stimulation (core phenomenon) when they were faced with sexual harassing behaviors (causal conditions). Such stimulation prompted three types of coping strategies: silence, avoidance, or confrontation. Intervening factors like the characteristics of the Iranian society (including family mores, state-imposed hijab regulations, patriarchal culture, educational system, and regulatory monitoring) and contextual factors (including individual and environmental factors and particularly employer expectations) were found to influence the selection of strategies used as well as their potential consequences in challenging situations.

Conclusion

The current study used a grounded theory approach to produce an explanatory storyline that can be tested. Sexual harassment induces conflict-induced stimulation and responses are influenced by intervening conditions, contextual factors, selected strategies, and the perceived consequences of the response. The findings of the grounded theory study suggest that there are negative consequences, particularly in terms of lack of employer support and losing one's job, shame, and family disapproval which act as barriers for female saleswomen to counteracting sexual harassment from male customers. Such an understanding can also be applied to develop educational policies to support women as well as ameliorate the prevalence of this essentially illegal problem.

The criminalization of women with postpartum psychosis: "a call for action" for judicial change

PURPOSE

To prevent the incarceration and influence outcomes when criminal culpability is linked to postpartum psychosis.

METHODS

Infanticide, neonaticide and filicide are most often linked with postpartum psychosis, which affects 1-2 women per 1,000 births or 4,000 women each year in the United States. Multiple genetic, hormonal and psychosocial factors surrounding childbirth result in a 1 to 4% risk of infanticide in women with postpartum psychosis. The authors seek to increase awareness of postpartum psychosis and postpartum depression in state legislatures. Others are working to have it recognized in the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a specific illness. Specific postpartum legislation for those charged with crimes related to maternal mental illness is necessary.

RESULTS

In Illinois, the very first criminal law in the nation recognizing the pernicious effects of this illness went into effect in 2018. The authors and others are attempting to cause similar or broader legislation to be brought in other states. Several women have been released from extended incarceration utilizing this law.

CONCLUSIONS

This temporary mental illness can lead to tragic outcomes when hospitalization and crisis intervention is delayed or the illness is misdiagnosed. The legal/judicial system has not utilized the growing body of scientific developments that medical researchers have discovered in recent decades. The lack of a unique diagnostic classification in the DSM and the lack of postpartum criminal laws, lead to mentally ill mothers in the U.S. receiving excessively harsh sentences when prosecuted, evidenced both in trial and sentencing.

Transcriptome Analysis Revealed the Early Heat Stress Response in the Brain of Chinese Tongue Sole (Cynoglossus semilaevis)

As a common influencing factor in the environment, temperature greatly influences the fish that live in the water all their life. The essential economic fish Chinese tongue sole (Cynoglossus semilaevis), a benthic fish, will experience both physiological and behavioral changes due to increases in temperature. The brain, as the central hub of fish and a crucial regulatory organ, is particularly sensitive to temperature changes and will be affected. However, previous research has mainly concentrated on the impact of temperature on the gonads of C. semilaevis. Instead, our study examines the brain using transcriptomics to investigate specific genes and pathways that can quickly respond to temperature changes. The fish were subjected to various periods of heat stress (1 h, 2 h, 3 h, and 5 h) before extracting the brain for transcriptome analysis. After conducting transcriptomic analyses, we identified distinct genes and pathways in males and females. The pathways were mainly related to cortisol synthesis and secretion, neuroactive ligand-receptor interactions, TGF beta signaling pathway, and JAK/STAT signaling pathway, while the genes included the HSP family, tshr, c-fos, c-jun, cxcr4, camk2b, and igf2. Our study offers valuable insights into the regulation mechanisms of the brain's response to temperature stress.

Probiotic and prebiotic supplementation ameliorates chronic restraint stress-induced male reproductive dysfunction

Restraint stress (RS) can induce male reproductive deficits by activating the hypothalamic-pituitary-adrenal (HPA) axis and causing oxidative stress. Previous studies have shown that probiotics can alleviate neurological and metabolic disorders induced by stress. However, the effects of probiotics on RS-induced reproductive deficits have not been fully elucidated. This study aimed to investigate whether Lactobacillus rhamnosus NCDC-610 (Probiotic-1) and Lactobacillus fermentum NCDC-400 (Probiotic-2) with prebiotic (fructooligosaccharides (FOS)) could prevent RS-induced reproductive deficits. C57BL6/J mice were subjected to RS for four hours daily before oral administration of probiotics (4 × 109 CFU per mice) either separately or concurrently with FOS. The results showed that oral administration of Probiotic-1 and Probiotic-2 protected against RS-induced sperm deficits, including sperm count, motility, morphology, and histopathology of testes, and improved intestinal health. Furthermore, Probiotic-1 and Probiotic-2 prevented RS-induced changes in testosterone levels by up-regulating the expressions of steroidogenic acute regulatory protein (StAR), cytochrome P450 side-chain cleavage enzyme (P450scc), and 17β-hydroxysteroid dehydrogenase (17βHSD) in the testes. Additionally, Probiotic-1 and Probiotic-2 increased the activities of catalase and superoxide dismutase and reduced the fold change of interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-α), indicating a protective effect against RS-induced oxidative stress. Oral administration of Probiotic-1 and Probiotic-2, either separately or concurrently with FOS (probiotic dose of 4 × 109 CFU per mice and prebiotic 5% w/v), prevented RS-induced activation of the HPA axis and improved male fertility. These findings suggest that L. rhamnosus NCDC-610 and L. fermentum NCDC-400 are safe and effective probiotics for mitigating stress-induced male reproductive deficits.

Altered glucocorticoid reactivity and behavioral phenotype in rx3-/- larval zebrafish

Introduction

The transcription factor rx3 is important for the formation of the pituitary and parts of the hypothalamus. Mutant animals lacking rx3 function have been well characterized in developmental studies, but relatively little is known about their behavioral phenotypes.

Methods

We used cell type staining to reveal differences in stress axis architecture, and performed cortisol measurements and behavior analysis to study both hormonal and behavioral stress responses in rx3 mutants.

Results and Discussion

Consistent with the role of rx3 in hypothalamus and pituitary development, we show a distinct loss of corticotrope cells involved in stress regulation, severe reduction of pituitary innervation by hypothalamic cells, and lack of stress-induced cortisol release in rx3 mutants. Interestingly, despite these deficits, we report that rx3-/- larval zebrafish can still display nominal behavioral responses to both stressful and non-stressful stimuli. However, unlike wildtypes, mutants lacking proper pituitary-interrenal function do not show enhanced behavioral performance under moderate stress level, supporting the view that corticotroph cells are not required for behavioral responses to some types of stressful stimuli but modulate subtle behavioral adjustments under moderate stress.

ENVIRONMENTAL STRESSORS DIFFERENTIALLY MODULATE ANXIETY-LIKE BEHAVIOUR IN MALE AND FEMALE ZEBRAFISH

How differently male and female responds in a stressful situation is a matter of curiosity. Apart from curiosity, this opens a new arena to the synthesis of personalized/individualized medications. Here, we used zebrafish, a suitable experimental animal model to study stress and anxiety. We evaluated the differential responses in adult male and female zebrafish on the acute exposure of three different stressors: Caffeine (100mg/L), Conspecific alarm substance (3.5ml/L), and sight of sympatric predators (Leaf fish and Snakehead) with the help of two different behavioural paradigms (Novel tank test & Predator exposure). Behavioural responses were captured over 6minutes and quantified using Smart 3.0. Male zebrafish were found to be more responsive to caffeine treatment. Conspecific alarm substance-challenged males and females showed robust alarm reactions whereas females were found to be more prone to it. Female zebrafish showed statistically significant aversion to the visual representation of sympatric predators. Taken together, each stressor induced differential responses in male and female zebrafish.

Heat induces multiomic and phenotypic stress propagation in zebrafish embryos

Heat alters biology from molecular to ecological levels, but may also have unknown indirect effects. This includes the concept that animals exposed to abiotic stress can induce stress in naive receivers. Here, we provide a comprehensive picture of the molecular signatures of this process, by integrating multiomic and phenotypic data. In individual zebrafish embryos, repeated heat peaks elicited both a molecular response and a burst of accelerated growth followed by a growth slowdown in concert with reduced responses to novel stimuli. Metabolomes of the media of heat treated vs. untreated embryos revealed candidate stress metabolites including sulfur-containing compounds and lipids. These stress metabolites elicited transcriptomic changes in naive receivers related to immune response, extracellular signaling, glycosaminoglycan/keratan sulfate, and lipid metabolism. Consequently, non-heat-exposed receivers (exposed to stress metabolites only) experienced accelerated catch-up growth in concert with reduced swimming performance. The combination of heat and stress metabolites accelerated development the most, mediated by apelin signaling. Our results prove the concept of indirect heat-induced stress propagation toward naive receivers, inducing phenotypes comparable with those resulting from direct heat exposure, but utilizing distinct molecular pathways. Group-exposing a nonlaboratory zebrafish line, we independently confirm that the glycosaminoglycan biosynthesis-related gene chs1 and the mucus glycoprotein gene prg4a, functionally connected to the candidate stress metabolite classes sugars and phosphocholine, are differentially expressed in receivers. This hints at the production of Schreckstoff-like cues in receivers, leading to further stress propagation within groups, which may have ecological and animal welfare implications for aquatic populations in a changing climate.

NR3C1 rs6198 Variant May Be Involved in the Relationship of Graves' Disease with Stressful Events

Although stressful events are known to trigger Graves' disease (GD), the mechanisms involved in this process are not well understood. The NR3C1 gene, encoding for the glucocorticoid receptor (GR), presents single nucleotide polymorphisms (SNPs) that are associated with stress-related diseases. To investigate the relationship between NR3C1 SNPs, GD susceptibility, and clinical features, we studied 792 individuals, including 384 patients, among which 209 presented with Graves' orbitopathy (GO), and 408 paired healthy controls. Stressful life events were evaluated in a subset of 59 patients and 66 controls using the IES-R self-report questionnaire. SNPs rs104893913, rs104893909, and rs104893911 appeared at low frequencies and presented similar profiles in patients and controls. However, variant forms of rs6198 were rarer in GD patients, suggesting a protective effect. Stressful events were more common in patients than controls, and were reported to have clearly occurred immediately before the onset of GD symptoms in 23 cases. However, no association was found between these events and rs6198 genotypes or GD/GO characteristics. We suggest that the NR3C1 rs6198 polymorphism may be an important protective factor against GD, but its relationship with stressful events needs further investigation.

Basic Concepts and Hormonal Regulators of the Stress System

BACKGROUND

Human organisms have to cope with a large number of external or internal stressful stimuli that threaten - or are perceived as threatening - their internal dynamic balance or homeostasis. To face these disturbing forces, or stressors, organisms have developed a complex neuroendocrine system, the stress system, which consists of the hypothalamic-pituitary-adrenal axis and the locus caeruleus/norepinephrine-autonomic nervous system.

SUMMARY

Upon exposure to stressors beyond a certain threshold, the activation of the stress system leads to a series of physiological and behavioral adaptations that help achieve homeostasis and increase the chances of survival. When, however, the stress response to stressors is inadequate, excessive, or prolonged, the resultant maladaptation may lead to the development of several stress-related pathologic conditions. Adverse environmental events, especially during critical periods of life, such as prenatal life, childhood, and puberty/adolescence, in combination with the underlying genetic background, may leave deep, long-term epigenetic imprints in the human expressed genome.

KEY MESSAGES

In this review, we describe the components of the stress system and its functional interactions with other homeostatic systems of the organism; we present the hormonal regulators of the stress response, and we discuss the development of stress-related pathologies.

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.

DHEAS and nutritional status among Sidama, Ngandu, and Aka children: Effects of cortisol and implications for adrenarche

OBJECTIVE

Adrenarche, the biological event marked by rising production of dehydroepiandrosterone and its sulfate (DHEAS), may represent a sensitive period in child development, with important implications for adolescence and beyond. Nutritional status, particularly BMI and/or adiposity, has long been hypothesized as a factor in DHEAS production but findings are inconsistent, and few studies have examined this among non-industrialized societies. In addition, cortisol has not been included in these models. We here evaluate effects of height- (HAZ), weight- (WAZ), and BMI- (BMIZ) for-age on DHEAS concentrations among Sidama agropastoralist, Ngandu horticulturalist, and Aka hunter-gatherer children.

METHODS

Heights and weights were collected from 206 children aged 2-18 years old. HAZ, WAZ, and BMIZ were calculated using CDC standards. DHEAS and cortisol assays were used to determine biomarker concentrations in hair. Generalized linear modeling was used to examine effects of nutritional status on DHEAS concentrations, as well as cortisol, controlling for age, sex, and population.

RESULTS

Despite the prevalence of low HAZ and WAZ scores, the majority (77%) of children had BMI z-scores >-2.0 SD. Nutritional status has no significant effect on DHEAS concentrations, controlling for age, sex, and population. Cortisol, however, is a significant predictor of DHEAS concentrations.

CONCLUSIONS

Our findings do not support a relationship between nutritional status and DHEAS. Instead, results suggest an important role for stress and ecology in DHEAS concentrations across childhood. Specifically, effects of environment via cortisol may be influential to patterning of DHEAS. Future work should investigate local ecological stressors and their relationship to adrenarche.

Stress resilience is established during development and is regulated by complement factors

Individuals in a population respond differently to stressful situations. While resilient individuals recover efficiently, others are susceptible to the same stressors. However, it remains challenging to determine if resilience is established as a trait during development or acquired later in life. Using a behavioral paradigm in zebrafish larvae, we show that resilience is a stable and heritable trait, which is determined and exhibited early in life. Resilient larvae show unique stress-induced transcriptional response, and larvae with mutations in resilience-associated genes, such as neuropeptide Y and miR218, are less resilient. Transcriptome analysis shows that resilient larvae downregulate multiple factors of the innate immune complement cascade in response to stress. Perturbation of critical complement factors leads to an increase in resilience. We conclude that resilience is established as a stable trait early during development and that neuropeptides and the complement pathway play positive and negative roles in determining resilience, respectively.

Role of the Neuroendocrine System of Marine Bivalves in Their Response to Hypoxia

Mollusks comprise one of the largest phylum of marine invertebrates. With their great diversity of species, various degrees of mobility, and specific behavioral strategies, they haveoccupied marine, freshwater, and terrestrial habitats and play key roles in many ecosystems. This success is explained by their exceptional ability to tolerate a wide range of environmental stresses, such as hypoxia. Most marine bivalvemollusksare exposed to frequent short-term variations in oxygen levels in their marine or estuarine habitats. This stressfactor has caused them to develop a wide variety of adaptive strategies during their evolution, enabling to mobilize rapidly a set of behavioral, physiological, biochemical, and molecular defenses that re-establishing oxygen homeostasis. The neuroendocrine system and its related signaling systems play crucial roles in the regulation of various physiological and behavioral processes in mollusks and, hence, can affect hypoxiatolerance. Little effort has been made to identify the neurotransmitters and genes involved in oxygen homeostasis regulation, and the molecular basis of the differences in the regulatory mechanisms of hypoxia resistance in hypoxia-tolerant and hypoxia-sensitive bivalve species. Here, we summarize current knowledge about the involvement of the neuroendocrine system in the hypoxia stress response, and the possible contributions of various signaling molecules to this process. We thusprovide a basis for understanding the molecular mechanisms underlying hypoxic stress in bivalves, also making comparisons with data from related studies on other species.

A Genomic Study of the Japanese Population Focusing on the Glucocorticoid Receptor Interactome Highlights Distinct Genetic Characteristics Associated with Stress Response

All living organisms have been programmed to maintain a complex inner equilibrium called homeostasis, despite numerous adversities during their lifespan. Any threatening or perceived as such stimuli for homeostasis is termed a stressor, and a highly conserved response system called the stress response system has been developed to cope with these stimuli and maintain or reinstate homeostasis. The glucocorticoid receptor, a transcription factor belonging to the nuclear receptors protein superfamily, has a major role in the stress response system, and research on its interactome may provide novel information regarding the mechanisms underlying homeostasis maintenance. A list of 149 autosomal genes that have an essential role in GR function or are prime examples of GRE-containing genes was composed in order to gain a comprehensive view of the GR interactome. A search for SNPs on those particular genes was conducted on a dataset of 3554 Japanese individuals, with mentioned polymorphisms being annotated with relevant information from the ClinVar, LitVar, and dbSNP databases. Forty-two SNPs of interest and their genomic locations were identified. These SNPs have been associated with drug metabolism and neuropsychiatric, metabolic, and immune system disorders, while most of them were located in intronic regions. The frequencies of those SNPs were later compared with a dataset consisting of 1465 Korean individuals in order to find population-specific characteristics based on some of the identified SNPs of interest. The results highlighted.that rs1043618 frequencies were different in the two populations, with mentioned polymorphism having a potential role in chronic obstructive pulmonary disease in response to environmental stressors. This SNP is located in the HSPA1A gene, which codes for an essential GR co-chaperone, and such information showcases that similar gene may be novel genomic targets for managing or combatting stress-related pathologies.

The Effect of Earthing Mat on Stress-Induced Anxiety-like Behavior and Neuroendocrine Changes in the Rat

Grounding is a therapeutic technique that involves doing activities that “ground” or electrically reconnect us to the earth. The physiological effects of grounding have been reported from a variety of perspectives such as sleep or pain. However, its anti-stress efficacy is relatively unknown. The present study investigated the stress-related behavioral effects of earthing mat and its neurohormonal mechanisms in the Sprague−Dawley male rat. Rats were randomly divided into four groups: the naïve normal (Normal), the 21 days immobilization stressed (Control), the 21 days stressed + earthing mat for 7 days (A7) or 21 days (A21) group. The depressive-and anxiety like behaviors were measured by forced swimming test (FST), tail suspension test (TST) and elevated plus maze (EPM). Using immunohistochemistry, the expression of corticotrophin-releasing factor (CRF) and c-Fos immunoreactivity were analyzed in the brain. In the EPM, time spent in the open arm of the earthing mat groups was significantly increased compared to the Control group (p < 0.001), even though there were without effects among groups in the FST and TST. The expression of CRF immunoreactive neurons in the earthing mat group was markedly decreased compared to the Control group. Overall, the earthing mat reduced stress-induced behavioral changes and expression of c-Fos and CRF immunoreactivity in the brain. These results suggest that the earthing mat may have the potential to improve stress-related responses via the regulation of the corticotrophinergic system.

The Hormesis Model for Building Resilience Through Adversity: Attention to Mechanism in Developmental Context

In developmental science, resilience refers to children and youths’ ability to recover and pursue positive development in the face of stress related to adversity. Extant research has documented protective factors and ecological contexts that mitigate the impact of adversity and thereby promote resilience. One intriguing aspect of resilience is that individuals also develop strength in response to early adversity. However, very little theoretical guidance exists on the developmental mechanisms and contexts through which early adversity may lead to strengthening effects that confer the process of resilience. The strengthening mechanism in the context of specific circumscribed environmental stress is a process known in the field of toxicology as hormesis. It is proposed here that the study of resilience in developmental and psychological sciences can benefit from shifting more attention to the hormesis model. The hormesis model is reviewed and discussed as a promising perspective on mechanisms, developmental timing, and context through which adversity strengthens or impedes resilience.

Sparus aurata and Lates calcarifer skin microbiota under healthy and diseased conditions in UV and non-UV treated water

Background

The welfare of farmed fish is influenced by numerous environmental and management factors. Fish skin is an important site for immunity and a major route by which infections are acquired. The objective of this study was to characterize bacterial composition variability on skin of healthy, diseased, and recovered Gilthead Seabream (Sparus aurata) and Barramundi (Lates calcarifer). S. aurata, which are highly sensitive to gram-negative bacteria, were challenged with Vibrio harveyi. In addition, and to provide a wider range of infections, both fish species (S. aurata and L. calcarifer) were infected with gram-positive Streptococcus iniae, to compare the response of the highly sensitive L. calcarifer to that of the more resistant S. aurata. All experiments also compared microbial communities found on skin of fish reared in UV (a general practice used in aquaculture) and non-UV treated water tanks.

Results

Skin swab samples were taken from different areas of the fish (lateral lines, abdomen and gills) prior to controlled infection, and 24, 48 and 72 h, 5 days, one week and one-month post-infection. Fish skin microbial communities were determined using Illumina iSeq100 16S rDNA for bacterial sequencing. The results showed that naturally present bacterial composition is similar on all sampled fish skin sites prior to infection, but the controlled infections (T₁ 24 h post infection) altered the bacterial communities found on fish skin. Moreover, when the naturally occurring skin microbiota did not quickly recover, fish mortality was common following T₁ (24 h post infection). We further confirmed the differences in bacterial communities found on skin and in the water of fish reared in non-UV and UV treated water under healthy and diseased conditions.

Conclusions

Our experimental findings shed light on the fish skin microbiota in relation to fish survival (in diseased and healthy conditions). The results can be harnessed to provide management tools for commercial fish farmers; predicting and preventing fish diseases can increase fish health, welfare, and enhance commercial fish yields.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-022-00191-y.

Immunoglobulin A and Physiologic Correlates of Well-Being in Asian Elephants

Zoological institutions aim to continually improve the lives of the animals under their stewardship. To this end, bull elephants are now increasingly maintained in all-male groups to mimic social conditions observed in the wild. While cortisol is the most frequently used “stress” biomarker, secretory immunoglobulin A (sIgA) as a measure of health and positive affect, and the social hormone, oxytocin, are increasingly viewed as additional markers of welfare. The introduction of a pair of bull elephants to an existing group of three bull elephants at Denver Zoo presented an opportunity to assess sIgA, oxytocin and cortisol in response to the socialization process. In this study, sIgA varied greatly between individuals and did not correlate with cortisol but did correlate with salivary oxytocin. sIgA and oxytocin concentrations differed the most between social and solo situations during the introduction period compared to before bulls were introduced, and after a stable group had been formed. In contrast to findings in some species, sIgA and oxytocin were higher when housed alone than socially. Nonetheless, these results suggest that sIgA and oxytocin may be involved in social engagement and establishment of new social dynamics, and thus provide more insight into overall welfare states.

Investigation of long-term bisphenol A exposure on rainbow trout (Oncorhynchus mykiss): Hematological parameters, biochemical indicator, antioxidant activity, and histopathological examination

As an industrial synthetic chemical, bisphenol A (BPA) has the potential to have physiologically and histologically adverse effects on aquatic organisms. BPA causes the reproductive disrupting of all vertebrates due to its degradation on endocrine system. Therefore, the effect of BPA on fish with high economic value is an important issue. This study focused weekly on long-term BPA exposure on rainbow trout (Oncorhynchus mykiss). Hematological, biochemical, antioxidant activity and histopathological examinations were performed on O. mykiss exposed to 1000 μg/L BPA concentration. Mortality was observed in the BPA group during the first three weeks. As a result of hematological studies, leukocyte count and hemoglobin in the BPA group were significantly higher in the first three weeks compared to the control group. Plasma cortisol level as a biochemical indicator showed a similar trend to leukocyte and hemoglobin. There was no significant difference between BPA and control groups in terms of superoxide dismutase and catalase. However, glutathione peroxidase activity in the BPA group was significantly lower than in the control group for four weeks. At the end of the study, many alterations were observed histologically in the gill tissues. While more intense hyperplasia and epithelial lifting were observed in the tissues in the BPA group compared to the control group, vacuolization, necrosis and hypertrophy were observed infrequently. In conclusion, this study argues that BPA causes negative effects on O. mykiss in terms of fish welfare and future study should be focused on its environmental adaptation with color preference patterns.

Comparison of TWA and PEP as indices of α2- and ß-adrenergic activation

RATIONALE

Pre-ejection period (PEP) and T-wave amplitude (TWA) have been used to assess sympathetic nervous system (SNS) activity. Here we report two single-blinded, placebo-controlled intravenous (IV) drug application studies in which we pharmacologically modified SNS activity with epinephrine (study 1) as well as dexmedetomidine (alpha2-agonist) and yohimbine (alpha2-antagonist) (study 2). Restricted heart rate (HR) intervals were analyzed to avoid confounding effects of HR changes.

OBJECTIVE

Study 1 served to replicate previous findings and to validate our approach, whereas study 2 aimed to investigate how modulation of central SNS activity affects PEP and TWA.

METHODS

Forty healthy volunteers (58% females) participated in study 1 (between-subject design). Twelve healthy men participated in study 2 (within-subject design). TWA and PEP were derived from ECG and impedance cardiography, respectively.

RESULTS

Epinephrine shortened PEP and induced statistically significant biphasic TWA changes. However, although the two alpha2-drugs significantly affected PEP as expected, no effects on TWA could be detected.

CONCLUSION

PEP is better suited to reflect SNS activity changes than TWA.

Ulexite modulates the neurotoxicological outcomes of acetylferrocene-exposed rainbow trout

In this study, the neuroprotective action potential by ulexite (UX) (18.75 mg/L) against acetylferrocene (AFC) (3.82 mg/L) induced neurotoxicity was aimed to investigate in brain tissues of Oncorhynchus mykiss. For this purpose, the effects on neurotoxicity markers, proinflammatory cytokines, antioxidant immune system, DNA, and apoptosis mechanisms were assessed on brain tissues in the 48-96  h of the 96- trial period. In this research, it was determined that brain-derived nerve cell growth factor (BDNF) level and acetylcholinesterase (AChE) activity were inhibited in the brain tissue compared to the control group by AFC. In addition, inhibition in glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) values (which are antioxidant system biomarkers), and inductions in malondialdehyde (MDA) and myeloperoxidase (MPO) amounts (which are indicators of lipid peroxidation) were determined (p < 0.05) after exposure to AFC. And, while tumor necrosis factor-α (TNF-α) and IL-6 levels were increased in the AFC-exposed group, Nrf-2 levels were found to be remarkably decreased. Upregulation was also detected in 8-hydroxydeoxyguanosine (8-OHdG) and caspase-3 levels, which are related to DNA damage and apoptosis mechanism. On the contrary, UX (single/with AFC) suppressed the AChE and BDNF inhibition by AFC. Moreover, UX mitigated AFC-induced oxidative, inflammatory, and DNA damage and attenuated AFC-mediated neurotoxicity via activating Nrf2 signaling in fish. Collectively, our findings revealed that UX supplementation might exert beneficial effects and may be considered as a natural and promising neuroprotective agent against AFC-induced toxicity.

Primary stress response and biochemical profile of Labeo rohita (Hamilton, 1822) experimentally parasitized with Argulus bengalensis (Ramakrishna, 1951)

Argulosis is a major problem that causes huge economic loss in aquaculture. In a microcosm, an infested condition was developed upon Labeo rohita with 100 ± 10 adult morphs of Argulus bengalensis per fish. Primary stress response and biochemical profiles of the host were evaluated to underscore the pathogenicity of the parasites. Significant alterations in biochemical parameters were monitored at four different post-infestation time points: days 1, 3, 6 and 9. The overall increasing trends of both plasma cortisol and plasma epinephrine indicate parasite-induced primary stress response among experimental fish. The study revealed a hyperglycaemic trend throughout the infestation period, which has been correlated with hypoxia-associated glycogenolysis. Decreasing level of plasma cholesterol has also been correlated with the development of anaemia and subsequent hypoxia among the infested fish. Plasma protein of the experimental fish initially increases as an outcome of the immediate innate immune response against Argulus infestation, whereas the decrease in plasma protein at the later period of infestation results from less-dietary protein intake due to loss of appetite, reduced digestibility and metabolic proteolysis. Plasma Na⁺ concentration showed an overall decreasing trend throughout the infestation period, which may be due to excess production of catecholamine under stress. Nonetheless, plasma K⁺ concentration showed an increasing trend up to day 6 of infestation, and thereafter the value declined to the control level. Plasma ionic imbalances reflect changes in cell permeability under tissue hypoxia and the wounds produced on the skin for intensive feeding activity of the parasites. Both serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase activities were significantly elevated throughout the infestation period, which indicates excess synthesis or release of those enzymes from the damaged cells of the tissues. Activities of some renal, hepatic and branchial antioxidant enzymes, viz., superoxide dismutase, catalase and glutathione-S-transferase, increased in the infested fish. The fact is explained as an effort of the fish for gaining adaptive adjustment to neutralize the oxidative stress generated under the parasitic stress. The overall experimental result points towards the generation of potential stress upon host fish by this branchiuran parasite. The biochemical alterations of the fish under argulosis are centred around the two stress-sensitive hormones, cortisol and epinephrine. The outcome of the study will be the important physiological determinants in adopting a suitable control measure as well as assessing the nutritional value of the fish under diseased condition.

Study protocol for measuring the impact of (quasi-)monochromatic light on post-awakening cortisol secretion under controlled laboratory conditions

Cortisol secretion has a fundamental role in human circadian regulation. The cortisol awakening response (CAR) can be observed as a daily recurring sharp increase in cortisol concentration within the first hour after awakening and is influenced by environmental light conditions. The current work provides the study protocol for an ongoing research project that is intended to explore the spectral dependencies and to discuss measures of emotional state and cognitive functioning potentially related to the CAR. Based on a controlled within-subjects sleep laboratory study, the impact of a two-hour, (quasi-)monochromatic, post-awakening light exposure of different peak wavelength (applied from 6:00 to 8:00 am) on resulting CAR levels should be investigated in a systematic manner to eventually derive a corresponding spectral sensitivity model. As a secondary outcome, it should be explored whether a potentially light-enhanced cortisol secretion might also impact different measures of sleepiness, mood, and vigilance for certain wavelengths. The study protocol described in the present work discusses the various protocol steps using pilot data collected for two different wavelength settings (i.e., short-wavelength blue-light at λmax = 476 nm and long-wavelength red-light at λmax = 649 nm) experienced by a group of four healthy male adults at an average ± SD age of 25.25 ± 3.59 years.

Effects of Group-delivered Stress-reduction Guided Imagery on Salivary Cortisol, Salivary Amylase, and Stress Mood in Urban, Predominantly Latino Adolescents

Objectives

To determine acute effects of stress-reduction guided imagery delivered in group format on stress biomarkers salivary cortisol and salivary amylase, and on self-reported stress mood, in healthy, predominantly Latino adolescents.

Study Design

111 adolescent participants (94% Latino), a subset from a large, randomized controlled lifestyle intervention to improve obesity-related health behaviors, received either 4 weekly lifestyle education sessions (Lifestyle group; LS) or the same weekly lifestyle education sessions plus an additional weekly stress-reduction guided imagery session delivered in group format (Guided imagery group; GI). Salivary cortisol, salivary amylase, and self-reported stress moods were assessed before and after sessions on intervention weeks 3 and 4. Statistics: Linear mixed effects models examined within- and between-session and group differences in pre- to post-session changes.

Results

Both groups showed decreases in salivary cortisol, 5% decrease in LS group and 32% in GI group (within-group differences all P < .05), with between-group difference in salivary cortisol of moderate size (P = .05; Cohen’s d = .44). Within the GI group alone, salivary cortisol decrease was similar following either the lifestyle or GI sessions (P = .64). There were no statistically significant amylase changes within or between groups. All 5 individual stress moods declined by 27% to 46% in the GI group (all P < .05), while only 1 of the 5 declined in LS group.

Conclusions

Group stress-reduction guided imagery reduces the stress biomarker salivary cortisol, as well as reducing subjective stress mood states, making it a viable modality for large scale stress-reduction interventions.

Environmental Stressors and Pathology of Marine Molluscs

Mollusca is one of the most species-rich phylum of the Animal Kingdom, comprising a wide range of both terrestrial and aquatic organisms [...]

Effects of NO modulators and antioxidants on endocrine and cellular markers in rats under repetitive restraint stress

The aim of the study was to evaluate the effects of NO modulators and antioxidant treatments on endocrine (plasma corticosterone), cellular (heat shock protein 70 [HSP-70] and nuclear factor κB [NF-κB]), and oxidative stress markers in repetitively stressed rats. Repetitive (restraint) stress (RS 1hr/day × 21 days) enhanced the levels of cellular and endocrine stress markers in the rat blood and altered pro-oxidant-antioxidant balance differentially in the control and test groups. Exposure to repetitive RS enhanced malondialdehyde (MDA) levels, lowered reduced glutathione (GSH), and superoxide dismutase (SOD) levels as well as nitric oxide (NOx) levels. NO precursor L-arginine and NO synthase inhibitors were found to differentially modulate stress-induced mechanism in altering NF-κB, HSP-70, and corticosterone levels. The antioxidant L-ascorbic acid (L-AA) significantly suppressed RS(×21)-induced elevation of NF-κB and HSP-70 levels, depicting protective effects, as also evidenced by reversal of elevated corticosterone levels. The results suggest that NO modulators and antioxidants differentially influence repetitive stress-induced changes in endocrine and cellular markers, and the complex interaction between NO and cellular markers like HSP70 and NF-κB plays a crucial modulatory role in this phenomenon.

Measuring subjective stress among young people in Hong Kong: validation and predictive utility of the single-item subjective level of stress (SLS-1) in epidemiological and longitudinal community samples

Aims

Brief measurements of the subjective experience of stress with good predictive capability are important in a range of community mental health and research settings. The potential for large-scale implementation of such a measure for screening may facilitate early risk detection and intervention opportunities. Few such measures however have been developed and validated in epidemiological and longitudinal community samples. We designed a new single-item measure of the subjective level of stress (SLS-1) and tested its validity and ability to predict long-term mental health outcomes of up to 12 months through two separate studies.

Methods

We first examined the content and face validity of the SLS-1 with a panel consisting of mental health experts and laypersons. Two studies were conducted to examine its validity and predictive utility. In study 1, we tested the convergent and divergent validity as well as incremental validity of the SLS-1 in a large epidemiological sample of young people in Hong Kong (n = 1445). In study 2, in a consecutively recruited longitudinal community sample of young people (n = 258), we first performed the same procedures as in study 1 to ensure replicability of the findings. We then examined in this longitudinal sample the utility of the SLS-1 in predicting long-term depressive, anxiety and stress outcomes assessed at 3 months and 6 months (n = 182) and at 12 months (n = 84).

Results

The SLS-1 demonstrated good content and face validity. Findings from the two studies showed that SLS-1 was moderately to strongly correlated with a range of mental health outcomes, including depressive, anxiety, stress and distress symptoms. We also demonstrated its ability to explain the variance explained in symptoms beyond other known personal and psychological factors. Using the longitudinal sample in study 2, we further showed the significant predictive capability of the SLS-1 for long-term symptom outcomes for up to 12 months even when accounting for demographic characteristics.

Conclusions

The findings altogether support the validity and predictive utility of the SLS-1 as a brief measure of stress with strong indications of both concurrent and long-term mental health outcomes. Given the value of brief measures of mental health risks at a population level, the SLS-1 may have potential for use as an early screening tool to inform early preventative intervention work.

Hormone seasonality in medical records suggests circannual endocrine circuits

We provide a dataset of millions of hormone tests from medical records that shows seasonality with a winter−spring peak in hormones for reproduction, growth, metabolism, and stress adaptation. Together with a long history of studies on a winter−spring peak in human function and growth, the hormone seasonality indicates that, like other animals, humans may have a physiological peak season for basic biological functions. We further use the specific seasonal phases of the hormones to suggest a model for a circannual clock in humans and animals that can keep track of the seasons, similar in spirit to the circadian clock that keeps track of time of day.

Hormones control the major biological functions of stress response, growth, metabolism, and reproduction. In animals, these hormones show pronounced seasonality, with different set-points for different seasons. In humans, the seasonality of these hormones remains unclear, due to a lack of datasets large enough to discern common patterns and cover all hormones. Here, we analyze an Israeli health record on 46 million person-years, including millions of hormone blood tests. We find clear seasonal patterns: The effector hormones peak in winter−spring, whereas most of their upstream regulating pituitary hormones peak only months later, in summer. This delay of months is unexpected because known delays in the hormone circuits last hours. We explain the precise delays and amplitudes by proposing and testing a mechanism for the circannual clock: The gland masses grow with a timescale of months due to trophic effects of the hormones, generating a feedback circuit with a natural frequency of about a year that can entrain to the seasons. Thus, humans may show coordinated seasonal set-points with a winter−spring peak in the growth, stress, metabolism, and reproduction axes.

Integrating the monoamine and cytokine hypotheses of depression: Is histamine the missing link?

Psychiatric diseases, like depression, largely affect the central nervous system (CNS). While the underlying neuropathology of depressive illness remains to be elucidated, several hypotheses have been proposed as molecular underpinnings for major depressive disorder, including the monoamine hypothesis and the cytokine hypothesis. The monoamine hypothesis has been largely supported by the pharmaceuticals that target monoamine neurotransmitters as a treatment for depression. However, these antidepressants have come under scrutiny due to their limited clinical efficacy, side effects, and delayed onset of action. The more recent, cytokine hypothesis of depression is supported by the ability of immune-active agents to induce "sickness behaviour" akin to that seen with depression. However, treatments that more selectively target inflammation have yielded inconsistent antidepressive results. As such, neither of these hypotheses can fully explain depressive illness pathology, implying that the underlying neuropathological mechanisms may encompass aspects of both theories. The goal of the current review is to integrate these two well-studied hypotheses and to propose a role for histamine as a potential unifying factor that links monoamines to cytokines. Additionally, we will focus on stress-induced depression, to provide an updated perspective of depressive illness research and thereby identify new potential targets for the treatment of major depressive disorder.

Cytokine profiling: variation in immune modulation with preterm birth vs. uncomplicated term birth identifies pivotal signals in pathogenesis of preterm birth

OBJECTIVES

To assess deviations in longitudinally measured cytokines with preterm birth (PTB).

METHODS

Prospective longitudinal study targeting 80 subjects. Phlebotomy specimens for broad panel of cytokine analysis were obtained at three time (T) intervals: first trimester (T1: 8-14 weeks' gestation), second trimester (T2: 18-22 weeks' gestation), and third trimester (T3: 28-32 weeks' gestation). Important demographics and outcomes were tracked. Data were stratified and the target groups were analyzed as follows: "Uncomplicated" (delivered ≥37 weeks) or "Preterm Birth" (<37 weeks). Generalized Linear Modeling determined rate of change T1-T3 by outcome.

RESULTS

Complete data replete with phlebotomy at all three visits were obtained on 80 women. Birth outcomes were as follows: 11 Uncomplicated Term Birth (UTB), 28 PTB, 4 low birth weight (LBW), 16 OB complications (OBC), 11 current infections (IFN), and 10 mixed complications (MC=2 or more of the above). 28 PTB were compared to 11 uncomplicated term deliveries. In both groups, T helper type 1 (TH1) cytokine (IL-1β), pleiotrophic pro-inflammatory cytokine (IL-6), and counter-regulatory cytokine (IL-10) responses decreased over gestation, but rates of change in IL-1β, IL-6, and IL-10 were significantly different. Stratification of women by smoking status additionally demonstrated significant variance in immune status over the course of pregnancy.

CONCLUSIONS

Women delivering PTB demonstrated significant differences in cytokine trajectory over pregnancy; these data further validate key role played by immune regulation in directing pregnancy outcome. Likewise, smoking impacts longitudinal trajectory of cytokines over pregnancy.

Combining mental and physical stress: Synergy or interference?

Both cognitive stressors (such as mental arithmetic tasks) and physical stressors (such as the cold pressor test, CP) are among the most widely employed tools in acute stress research, and there is growing evidence for a high degree of stimulus-response specificity, rather than uniformity, in the human stress response. However, little is known about potential synergistic or interfering effects during concurrent administration. While cognitive tasks have been hypothesized to attenuate pain perception during CP, they are also thought to enhance physiological reactivity. Conversely, physical stress might interfere with effective stress induction by cognitive challenges. To address these questions, 56 participants underwent either the CP (3-min ice-water immersion of feet) or a warm-water control condition. In half of the sample, the Paced Auditory Serial Addition Task (PASAT) was performed simultaneously (fully crossed interventions). Salivary cortisol, cardiovascular parameters, and subjective ratings as well as voice pitch (F0) were assessed. Results show that cortisol responses, self-reported pain and subjective arousal were mainly driven by cold exposure, which also led to increased F0. The PASAT incrementally enhanced cardiovascular reactions, but did not affect pain ratings nor cortisol responses to the CP. However, intra-individual concordance between elevated blood pressure and other reactivity measures was enhanced by PASAT administration during the CP. Importantly, performance decrements in the mental-arithmetic task were not associated with diminished stress responses. In conclusion, our results speak against any strong interference when administering cognitive and painful physical stressors simultaneously, pointing rather to specific additive effects, particularly regarding cardiovascular reactivity.

Mediterranean diet, stress resilience, and aging in nonhuman primates

Persistent psychological stress increases the risk of many chronic diseases of aging. Little progress has been made to effectively reduce stress responses or mitigate stress effects suggesting a need for better understanding of factors that influence stress responses. Limited evidence suggests that diet may be a factor in modifying the effects of stress. However, long-term studies of diet effects on stress reactive systems are not available, and controlled randomized clinical trials are difficult and costly. Here we report the outcomes of a controlled, randomized preclinical trial of the effects of long-term consumption (31 months, ~ equivalent to 9 human years) of Western versus Mediterranean - like diets on behavioral and physiological responses to acute (brief social separation) and chronic (social subordination) psychosocial stress in 38 adult, socially-housed, female cynomolgus macaques. Compared to animals fed a Western diet, those fed the Mediterranean diet exhibited enhanced stress resilience as indicated by lower sympathetic activity, brisker and more overt heart rate responses to acute stress, more rapid recovery, and lower cortisol responses to acute psychological stress and adrenocorticotropin (ACTH) challenge. Furthermore, age-related increases in sympathetic activity and cortisol responses to stress were delayed by the Mediterranean diet. Population level diet modification in humans has been shown to be feasible. Our findings suggest that population-wide adoption of a Mediterranean-like diet pattern may provide a cost-effective intervention on psychological stress and promote healthy aging with the potential for widespread efficacy.

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There is no population level treatment to reduce stress and associated disease.

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Mediterranean diet reduced sympathetic activity.

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Mediterranean diet reduced cortisol response to acute stress and to ACTH challenge.

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Mediterranean diet delayed age-related increases in sympathetic activity and cortisol responses to stress.

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These results suggest a dietary strategy to increase stress resilience.

Comparative assessment of the acute toxicity, haematological and genotoxic effects of ten commonly used pesticides on the African Catfish, Clarias gariepinus Burchell 1822

Freshwater fishes are faced with increasing threats due to intensification of agriculture. This study evaluated the haematological and genotoxic effects of exposure of the African Catfish, Clarias gariepinus to sublethal concentrations of commonly used pesticides in agricultural settings. The evaluated pesticides were abamectin, carbofuran, chlorpyrifos, cypermethrin, deltamethrin, dichlorvos, dimethoate, fipronil, lambda-cyhalothrin and paraquat. The fishes were initially exposed singly to the pesticides for 96 h periods to determine their LC₅₀, followed by exposure to sublethal concentrations (1/100^th 96 h LC₅₀) over a 21 d period. In all cases, a control experiment with catfishes kept in dechlorinated municipal water was monitored simultaneously. The 96 h LC₅₀ values was found to vary widely from 2.043 μgL^-1 (Lambda-cyhalothrin) to 10284.288 μgL^-1(Paraquat). Significant differences (P < 0.05) were observed between mean haematological parameters-WBC, RBC, HGB, HCT, MCH and MCHC in the exposed and control catfishes. More so, micronucleus and nuclear abnormalities occurred at significantly higher proportions in pesticide exposed catfishes. Holistic cradle to grave approach as well as fate analysis is required to mitigate the potential harmful effects of pesticides to fresh water fishes.

Cortisol-Related Signatures of Stress in the Fish Microbiome

Exposure to environmental stressors can compromise fish health and fitness. Little is known about how stress-induced microbiome disruption may contribute to these adverse health effects, including how cortisol influences fish microbial communities. We exposed juvenile Atlantic salmon to a mild confinement stressor for two weeks. We then measured cortisol in the plasma, skin-mucus, and feces, and characterized the skin and fecal microbiome. Fecal and skin cortisol concentrations increased in fish exposed to confinement stress, and were positively correlated with plasma cortisol. Elevated fecal cortisol was associated with pronounced changes in the diversity and structure of the fecal microbiome. In particular, we identified a marked decline in the lactic acid bacteria Carnobacterium sp. and an increase in the abundance of operational taxonomic units within the classes Clostridia and Gammaproteobacteria. In contrast, cortisol concentrations in skin-mucus were lower than in the feces, and were not related to any detectable changes in the skin microbiome. Our results demonstrate that stressor-induced cortisol production is associated with disruption of the gut microbiome, which may, in turn, contribute to the adverse effects of stress on fish health. They also highlight the value of using non-invasive fecal samples to monitor stress, including simultaneous determination of cortisol and stress-responsive bacteria.

Non-pharmacological and pharmacological approaches for psychiatric disorders: Re-appraisal and insights from zebrafish models

Acute and chronic stressors are common triggers of human mental illnesses. Experimental animal models and their cross-species translation to humans are critical for understanding of the pathogenesis of stress-related psychiatric disorders. Mounting evidence suggests that both pharmacological and non-pharmacological approaches can be efficient in treating these disorders. Here, we analyze human, rodent and zebrafish (Danio rerio) data to compare the impact of non-pharmacological and pharmacological therapies of stress-related psychopathologies. Emphasizing the likely synergism and interplay between pharmacological and environmental factors in mitigating daily stress both clinically and in experimental models, we argue that environmental enrichment emerges as a promising complementary therapy for stress-induced disorders across taxa. We also call for a broader use of novel model organisms, such as zebrafish, to study such treatments and their potential interplay.

Role of neuroimmune circuits and pruritus in psoriasis

Psoriasis is a chronic inflammatory skin disease presenting with an array of clinical phenotypes, often associated with pruritus. Environmental and psychological stressors can exacerbate psoriasis symptoms and provoke flares. Recent studies suggest a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis in some patients with psoriasis that can result in immune dysregulation. The immune system, in turn, can communicate with the nervous system to induce, maintain or aggravate psoriasis. In the skin, peripheral sensory as well as autonomic nerves control release of inflammatory mediators from dendritic cells, mast cells, T cells or keratinocytes, thereby modulating inflammatory responses and, in case of sensory nerves, pruritus. In response to the environment or stress, cytokines, chemokines, proteases, and neuropeptides fluctuate in psoriasis and influence immune responses as well as nerve activity. Furthermore, immune cells communicate with sensory nerves which control release of cytokines, such as IL-23, that are ultimately involved in psoriasis pathogenesis. Nerves also communicate with keratinocytes to induce epidermal proliferation. Notably, in contrast to recent years the debilitating problem of pruritus in psoriasis has been increasingly appreciated. Thus, investigating neuroimmune communication in psoriasis will not only expand our knowledge about the impact of sensory nerves in inflammation and pruritus and give new insights into the impact of environmental factors activating neuroimmune circuits or of stress in psoriasis, but may also lead to novel therapies. This review summarizes the relevant literature on the role of neuroimmune circuits, stress and how the central HPA axis and its peripheral equivalent in the skin, impact psoriasis.

Stress hypothesis overload: 131 hypotheses exploring the role of stress in tradeoffs, transitions, and health

Stress is ubiquitous and thus, not surprisingly, many hypotheses and models have been created to better study the role stress plays in life. Stress spans fields and is found in the literature of biology, psychology, psychophysiology, sociology, economics, and medicine, just to name a few. Stress, and the hypothalamic-pituitaryadrenal/interrenal (HPA/I) axis and sympathetic nervous system (SNS), are involved in a multitude of behaviors and physiological processes, including life-history and ecological tradeoffs, developmental transitions, health, and survival. The goal of this review is to highlight and summarize the large number of available hypotheses and models, to aid in comparative and interdisciplinary thinking, and to increase reproducibility by a) discouraging hypothesizing after results are known (HARKing) and b) encouraging a priori hypothesis testing. For this review I collected 214 published hypotheses or models dealing broadly with stress. In the main paper, I summarized and categorized 131 of those hypotheses and models which made direct connections among stress and/or HPA/I and SNS, tradeoffs, transitions, and health. Of those 131, the majority made predictions about reproduction (n = 43), the transition from health to disease (n = 38), development (n = 23), and stress coping (n = 18). Additional hypotheses were classified as stage-spanning or models (n = 37). The additional 83 hypotheses found during searches were tangentially related, or pertained to immune function or oxidative stress, and these are listed separately. Many of the hypotheses share underlying rationale and suggest similar, if not identical, predictions, and are thus not mutually exclusive; some hypotheses spanned classification categories. Some of the hypotheses have been tested multiple times, whereas others have only been examined a few times. It is the hope that multi-disciplinary stress researchers will begin to harmonize their naming of hypotheses in the literature so as to build a clearer picture of how stress impacts various outcomes across fields. The paper concludes with some considerations and recommendations for robust testing of stress hypotheses.

Behavioral and Endocrine Alterations to Partner Interactions and Offspring Care during Periods of Conflict

Biparental care has evolved to ensure successful rearing of offspring. However, separation during periods of care can lead to conflicts that might negatively impact pair bonds and offspring care. In this study, pair-bonded convict cichlids (Amatitlania nigrofasciata) were observed for changes in behavior toward their partners and offspring before and after a period of separation. Males and females were designated either as a Resident (remain with offspring) or Removed (separated from partner and offspring for 5 days) individual. Behaviors between partners and toward offspring were measured before and after separation, and compared to the levels of behavior of control pairs (never separated), as well as individuals introduced to a novel partner instead. Cortisol levels of Resident male and female A. nigrofasciata were assayed using water-borne hormone collection before and after separation. Aggression between pair bond members did increase following reintroduction, but did not lead to the termination of pair bonds. Resident females showed more aggression to novel partners than Resident males. Offspring care decreased in both Resident and Removed females. Experimental pairs decreased the amount of time spent interacting with intruders. Cortisol levels were significantly higher among experimental pairs compared with control pairs that did not experience a separation. Females (both control and experimental) showed small, yet significant increases in cortisol levels, while both control and experimental males did not. These results suggest that while pair bonds appear resilient, prolonged separations influence pair bond and parental care dynamics, both behaviorally and hormonally, and require pairs to re-establish roles, resulting in less time caring for offspring.