The influence of selected factors on wool cortisol concentration in alpacas (Vicugna pacos)

Several internal and external factors can influence animals' hormonal activity. Cortisol level in hair and wool determines chronic stress, which is connected with the long-term HPA axis effect. Wool cortisol levels in alpacas have never been determined to this time. The study aimed to assess the influence of selected factors on wool cortisol concentration in alpacas. The study included 36 alpacas. Wool samples were collected during shearing in June 2021, cut with an electric clipper from the right shoulder and the rump. Wool samples were fragmented into proximal (winter-spring regrowth) and distal (summer-fall regrowth) segments. Alpacas' Heat Stress Index (HSI) for the summer of 2020 was 139.4, and 116 for the winter of 2021. The cortisol levels in the wool samples were determined with the General Cortisol ELISA Kit assay. The most significant differences in wool cortisol concentrations were caused by two factors: the wool segment (P < 0.001; η2 = 0.889) and the region on the body (P < 0.001; η2 = 0.876). Wool cortisol level was higher in the distal segment (referring to the summer-fall season) than in the proximal one (referring to the winter-spring season). It is suggested that alpacas can feel heat stress in summer (HSI = 139.4), which could influence higher cortisol levels in the distal segment. The wool cortisol level was higher in the rump samples than the shoulder ones. Therefore, it is essential in future studies that wool samples from all tested animals should be completed from the same body region. Differences among age and sex groups were also observed. Wool cortisol level was higher in older animals, as differences between age groups were observed in samples from the rump in the distal and proximal segments (distal, the rump younger*older: P < 0.001; η2 = 0.321; proximal, the rump older*younger: P = 0.007; η2 = 0.195). Males showed higher cortisol levels than females, as a difference between sexes was observed in samples from the rump in the proximal segment (P = 0.001, η2 = 0.271). This study emphasizes that various factors may significantly influence wool cortisol levels, which can be helpful in alpacas' welfare estimation using this hormonal indicator as a noninvasive long-term stress assessment method.

Perceived stress and renewal: The effects of long-term stress on the renewal effect

Two online experiments evaluated the relationship between long-term stress, as measured with the Perceived Stress Scale-10, and the Renewal Effect. In the first experiment renewal was assessed with a behavioral suppression task in a science-fiction based video game. Participants learned to suppress mouse clicking during a signal for an upcoming attack to avoid losing points. The signal was first paired with an attack in Context A and extinguished in Context B and tested back in Context A. The contexts were different space galaxies where the gameplay took place. Experiment 2 used a food/illness predictive-learning paradigm. Two food items were paired with stomachache in one restaurant (A) and extinguished in Context B prior to testing in both contexts without feedback. Positive correlations were obtained between renewal and stress in each experiment. Unlike acute stress (Drexler et al., 2017), long term stress was associated with greater renewal. The effects of stress, both chronic and punctual, on renewal are discussed.

How energy balance-related behaviours, temperament, stress and overweight associate: a cross-sectional study of Finnish preschoolers

OBJECTIVE

This study aimed to (1) examine the clustering of energy balance-related behaviours (EBRB) and (2) investigate whether EBRB clusters, temperament and hair cortisol concentration (HCC) associate with overweight.

DESIGN

We assessed food consumption using food records, screen time (ST) using sedentary behaviour diaries, sleep consistency and temperament (negative affectivity, surgency, effortful control) using questionnaires and HCC using hair samples. Accelerometers were used to assess physical activity (PA) intensities, sleep duration and sleep efficiency. Researchers measured each child's weight and height. We used finite mixture models to identify EBRB clusters and multilevel logistic regression models to examine the associations between EBRB clusters, temperament, HCC and overweight.

SETTING

The cross-sectional DAGIS survey, data collected in 2015-2016.

PARTICIPANTS

Finnish 3-6-year-olds (n 864) recruited through preschools.

RESULTS

One-third of the participants were categorised into the cluster labelled 'Unhealthy diet, excessive screen time', characterised by unhealthy dietary choices (e.g. greater consumption of high-fat, high-sugar dairy products) and longer ST. Two-thirds were categorised into the second cluster, labelled 'Healthy diet, moderate screen time'. PA and sleep were irrelevant for clustering. Higher negative affectivity and lower effortful control associated with the 'Unhealthy diet, excessive screen time' cluster. EBRB clusters and HCC did not associate with overweight, but surgency was positively associated with overweight (OR = 1·63, 95 % CI 1·17, 2·25).

CONCLUSIONS

Of the EBRB, food consumption and ST seem to associate. As temperament associates with EBRB clusters and overweight, tailored support acknowledging the child's temperament could be profitable in maintaining a healthy weight.

Validation and utility of hair cortisol analysis as a measure of long-term physiological stress in the Pallas's squirrel Callosciurus erythraeus

In various mammalian species, there has been an increase in the use of hair cortisol analysis to evaluate long-term stress. This trend is because of some advantages relative to the standard tools, such as hormone analysis using blood, urine, or feces. Here, I carried out assay validation and adrenocorticotrophic hormone (ACTH) challenge to measure long-term stress in Pallas's squirrel Callosciurus erythraeus. In addition, I investigated the effects of sex, body condition, season, and reproductive conditions on hair cortisol concentrations (HCC) in free-living individuals. The assay validation was reported in this study. Hair cortisol concentrations in squirrels given repeated ACTH injections were significantly higher than those that received a single-ACTH injection and a saline injection. I found a negative effect of body condition on adult HCC. In contrast, body condition had a positive effect on HCC in juveniles. I found no effects of other factors in either adult or juvenile squirrels. Furthermore, although I investigated whether reproductive conditions, such as pregnancy, lactation, and non-breeding in females or testis size in males, affected HCC, I found that there were no effects of reproductive conditions. This study validated the assay and utility of hair cortisol analysis to assess long-term stress, and continuous investigation of the relationship between HCC and fitness is important for determining whether hair cortisol analysis is a reliable method for estimating population health in Pallas's squirrels.

COVID-19 pandemic related long-term chronic stress on the prevalence of depression and anxiety in the general population

BACKGROUND

The COVID-19 pandemic has lasted for more than 1 year, causing far-reaching and unprecedented changes in almost all aspects of society. This study aimed to evaluate the long-term consequences of the COVID-19 pandemic on depression and anxiety, and explore the factors associated with it.

METHODS

A cross-sectional study using an online survey was conducted to assess mental health problems from February 2 to February 9, 2021 by using patient health questionnaire-9 (PHQ-9) and generalized anxiety disorder-7 (GAD-7). The insomnia severity index (ISI), demographic data and COVID-19 related variables were measured by a self-designed questionnaire. The factors associated with depressive and anxiety symptoms were identified by Pearson chi-square test and binary logistic regression analysis.

RESULTS

In the study that 1171 participants enrolled, the overall prevalence of depressive and anxiety symptoms among general people was 22.6 and 21.4% respectively in the present study. Living alone was a potential risk factor for depressive symptoms, while regular exercises was a potential protective factor. The prevalence of depressive and anxiety symptoms was significantly associated with the severity of insomnia symptoms and the negative feelings about pandemic.

CONCLUSION

COVID-19 pandemic- related chronic stress has brought about profound impacts on long-term mental health in the general population. The level of insomnia and a negative attitude towards the pandemic are significantly correlated with unfavorable mental health. However, we failed to found a significant association of age and gender with the mental health symptoms, although they were recognized as well-established risk factors during the outbreak by some other studies. This discrepancy may be because the acute and chronic effects of the pandemic are influenced by different factors, which reminds that more attention should be paid to the intrinsic psychological factors and physical reactions towards COVID-19.

Low hair cortisol concentrations in obsessive compulsive disorder: A cross-sectional study

Recent findings have highlighted the association between changes in the activity of the HPA axis, primarily its end-hormone, cortisol and OCD. However, to date, cortisol levels of OCD patients have been assessed mainly in body fluids, such as serum, saliva or urine, frequently leading to ambiguous results because of their inherent lack of stability. The aim of this study was to investigate time-integrated levels of stress exposure in 32 OCD patients and 32 sex and age-matched healthy controls by measuring endogenous cortisol in hair segments reflecting the last 3 months preceding hair collection. Psychometric parameters, including BDI, FQ, STAI, PSS and ECQ-R, were obtained in all participants; Y-BOCS was performed in the OCD patients. The OCD patients exhibited significantly higher scores in all psychometric instruments administered and lower hair cortisol concentrations than the healthy controls (p = 0.001, r = 0.41). No significant correlations were found between the HCC and the Y-BOCS total scores. After having sorted OCD patients into subtypes, according to the nature of their symptomatology, the "washers/cleaners" category showed the lowest HCC (compared to the "checking/harming", "ordering/symmetry" and "sexual/religious obsessions" categories). The novel finding of chronic low cortisol secretion in OCD patients could be attributed to a possible down-regulation of the HPA axis, as an adaptive response to chronic stress exposure. Given that the OCD subtypes reflect the great heterogeneity in the OCD spectrum, studies with larger samples should extend the investigation of HCC in patients with distinctive symptomatology, so as to develop a basis for better neuroendocrine profiling and understanding of the pathophysiology of OCD. Further work is needed in exploring HPA axis' activity over the natural course and treatments of the disorder.

Standardized multimodal intervention for stress-induced exhaustion disorder: an open trial in a clinical setting

BACKGROUND

Long-term sick-leave due to stress-related ill-health is increasing in several economically developed countries. Even though different forms of interventions are administered in regular care for stress-related disorders, such as Stress-induced Exhaustion disorder (SED), the scientific evidence for the effectiveness of such treatments is sparse. The objective of this study was to explore changes in SED-symptoms and return-to-work-rates in a large group of SED-patients participating in a standardized Multimodal intervention (MMI) in a clinical setting.

METHOD

This open clinical trial tracked 390 patients who fulfilled the criteria for SED undergoing a 24-week MMI, including return-to-work-strategies. Before inclusion, all patients underwent a multi-professional assessment by a team of licensed physicians, licensed psychologists, and licensed physiotherapists. Self-rated questionnaires were administered before treatment, at treatment-start, mid-treatment, post-treatment, and at 12-month follow-up. Within-group change was evaluated over time with mixed-effects models. Beyond different symptoms, working time, sick-leave compensation, and adverse effects were also measured.

RESULTS

There were significant improvements in symptoms of SED, burnout, anxiety, depression, and insomnia, with large within-group effect sizes (d = 0.91-1.76), improvements that were maintained at 12-month follow-up. Furthermore, there was a significant increase in quality of life and large improvements in average working time and sick-leave compensation. Some adverse effects were reported, mainly concerning an increase in stress, anxiety, and worry.

CONCLUSION

SED-patients participating in this standardized MMI reported large symptom alleviation, increased working time and reduced sick-leave compensation, indicating a beneficial treatment. There were some adverse effects, but no more so than other psychological treatments. This study confirms previous findings that high levels of depression and anxiety decrease to sub-clinical levels during treatment, while symptoms of SED also decline, yet still persists above sub-clinical levels at 12-month follow-up. On the whole, this open clinical trial suggests that a standardized MMI, administered in a clinical setting, improves symptoms and return-to-work rates in a clinically representative SED-population.

TRIAL REGISTRATION

This study was registered on Clinicaltrials.gov 2017.12.02 (Identifier: NCT03360136 ).

Is it getting in the hair? - Cortisol concentrations in native, regrown and segmented hairs of cattle and pigs after repeated ACTH administrations

Adrenocorticotropic hormone (ACTH) is part of the hypothalamic-pituitary-adrenal axis response to stress and induces the release of cortisol, which is commonly used as an indicator in stress and animal welfare research. In recent years, hair cortisol concentration (HCC) gained increasing importance as a promising retrospective indicator for stress in animals. Thus, the aim of our study was to validate HCC as a potential indicator of increased endogenous cortisol release in cattle and pigs by repeated ACTH administrations followed by cortisol analysis in different hair types. For this purpose, 34 cattle and 38 gilts were treated either with repeated i.m. injections of ACTH or saline every second day over a period of 4 weeks. Saliva samples were taken before and after injections once a week from selected animals to verify the endogenous cortisol response. At the end of the treatment (week 4) and after 8 and 12 weeks, samples of natural and regrown hair were taken from the caudo-dorsal region of the back and analyzed for cortisol concentrations. In addition, natural hair was sampled after 12 weeks and cut into segments prior to analysis. Treatment with ACTH revealed a significant increase in salivary cortisol after application in both species, although this increase was attenuated in pigs compared to cattle. In week 4, HCCs were significantly elevated in natural and regrown hair of ACTH-treated animals. In cattle, HCCs significantly increased after ACTH treatment in natural, regrown and segmental hair compared with control animals, indicating that HCC may be a promising indicator of stress, as cortisol levels in all hair types reflected the preceding period with increased cortisol release. In pigs, there were no differences in HCCs between treatments. This may be caused by the lower systemic cortisol response in pigs, but seasonally reduced hair growth and external cross-contamination of hair by saliva and urine under commercial husbandry conditions may also interfere with the validity of HCC in this species.

Effect of arsenic stress on 5-methylcytosine, photosynthetic parameters and nutrient content in arsenic hyperaccumulator Pteris cretica (L.) var. Albo-lineata

BACKGROUND

Arsenic toxicity induces a range of metabolic responses in plants, including DNA methylation. The focus of this paper was on the relationship between As-induced stress and plant senescence in the hyperaccumulator Pteris cretica var. Albo-lineata (Pc-Al). We assume difference in physiological parameters and level of DNA methylation in young and old fronds as symptoms of As toxicity.

RESULTS

The As accumulation of Pc-Al fronds, grown in pots of haplic chernozem contaminated with 100 mg As kg- 1 for 122 days, decreased with age. Content of As was higher in young than old fronds for variants with 100 mg As kg- 1 (2800 and 2000 mg As kg- 1 dry matter, respectively). The highest As content was determined in old fronds of Pc-Al grown in pots with 250 mg As kg- 1. The increase with age was confirmed for determined nutrients - Cu, Mg, Mn, S and Zn. A significant elevation of all analysed nutrients was showed in old fronds. Arsenic accumulation affected DNA methylation status in fronds, but content of 5-methylcytosine (5mC) decreased only in old fronds of Pc-Al (from 25 to 12%). Determined photosynthetic processes showed a decrease of fluorescence, photosynthetic rate and chlorophylls of As treatments in young and old fronds. Water potential was decreased by As in both fronds. Thinning of the sclerenchymatous inner cortex and a reduction in average tracheid metaxylem in the vascular cylinder was showed in roots of As treatment. Irrespective to fronds age, physiological parameters positively correlated with a 5mC while negatively with direct As toxicity. Opposite results were found for contents of Cu, Mg, Mn, S and Zn.

CONCLUSIONS

The results of this paper point to changes in the metabolism of the hyperaccumulator plant Pc-Al, upon low and high exposure to As contamination. The significant impact of As on DNA methylation was found in old fronds. Irrespective to fronds age, significant correlations were confirmed for 5mC and As toxicity. Our analysis of the very low water potential values and lignification of cell walls in roots showed that transports of assimilated metabolites and water between roots and fronds were reduced. As was showed by our results, epigenetic changes could affect studied parameters of the As hyperaccumulator plant Pc-Al, especially in old fronds.

Within a hair's breadth - Factors influencing hair cortisol levels in pigs and cattle

During the last two decades, hair cortisol concentration (HCC) has proven to be a promising marker for the evaluation of increased hypothalamic-pituitary-adrenal axis activity caused by repeated or long-term stressful conditions. A minimally invasive sampling procedure, simple storage and the retrospective characteristic of one hair sample are reasons why HCC is increasingly used not only in human medicine but also in animal welfare research. However, before applying HCC as a reliable indicator for stress, it is important to investigate potential influencing factors in addition to stressors in the species of interest. Thus, the aim of our study was to elucidate the impact of age, sex, hair color, body region, age of hair segments and season of hair sampling on HCC in pigs and cattle. Hair samples were taken by electric clippers and analyzed by ELISA after extraction. Our results show similar effects of influencing factors in both species. Significantly increased HCCs were found in young animals after birth compared with older age groups. In addition, HCCs were significantly higher in samples obtained from the tail tip in comparison with samples from the shoulder, neck and back regions, in black hair compared with white hair and in distal hair segments. Season had an impact on HCC only in cattle, which exhibited higher levels in winter than in summer. In conclusion, age, body region, hair color, hair segment and season affect hair cortisol concentrations and should be considered and controlled for when HCC is applied as a potential stress indicator in pigs and cattle. In addition, further research is necessary to elucidate the mechanisms by which cortisol is incorporated into the hair shaft.

Alexithymia and frontal-amygdala functional connectivity in North Korean refugees

BACKGROUND

Refugees commonly experience difficulties with emotional processing, such as alexithymia, due to stressful or traumatic experiences. However, the functional connectivity of the amygdala, which is central to emotional processing, has yet to be assessed in refugees. Thus, the present study investigated the resting-state functional connectivity of the amygdala and its association with emotional processing in North Korean (NK) refugees.

METHODS

This study included 45 NK refugees and 40 native South Koreans (SK). All participants were administered the Toronto Alexithymia Scale (TAS), Beck Depression Inventory (BDI), and Clinician-administered PTSD Scale (CAPS), and differences between NK refugees and native SK in terms of resting-state functional connectivity of the amygdala were assessed. Additionally, the association between the strength of amygdala connectivity and the TAS score was examined.

RESULTS

Resting-state connectivity values from the left amygdala to the bilateral dorsolateral prefrontal cortex (dlPFC) and dorsal anterior cingulate cortex (dACC) were higher in NK refugees than in native SK. Additionally, the strength of connectivity between the left amygdala and right dlPFC was positively associated with TAS score after controlling for the number of traumatic experiences and BDI and CAPS scores.

CONCLUSIONS

The present study found that NK refugees exhibited heightened frontal-amygdala connectivity, and that this connectivity was correlated with alexithymia. The present results suggest that increased frontal-amygdala connectivity in refugees may represent frontal down-regulation of the amygdala, which in turn may produce alexithymia.

Seawater salt-trapped Pseudomonas aeruginosa survives for years and gets primed for salinity tolerance

Background

In nature, microorganisms have to adapt to long-term stressful conditions often with growth limitations. However, little is known about the evolution of the adaptability of new bacteria to such environments. Pseudomonas aeruginosa, an opportunistic pathogen, after natural evaporation of seawater, was shown to be trapped in laboratory-grown halite crystals and to remain viable after entrapment for years. However, how this bacterium persists and survives in such hypersaline conditions is not understood.

Results

In this study, we aimed to understand the basis of survival, and to characterise the physiological changes required to develop salt tolerance using P. aeruginosa as a model. Several clones of P. aeruginosa were rescued after 14 years in naturally evaporated marine salt crystals. Incubation of samples in nutrient-rich broth allowed re-growth and subsequent plating yielded observable colonies. Whole genome sequencing of the P. aeruginosa isolates confirmed the recovery of the original strain. The re-grown strains, however, showed a new phenotype consisting of an enhanced growth in growing salt concentration compared to the ancestor strain. The intracellular accumulation of K⁺ was elicited by high concentration of Na⁺ in the external medium to maintain the homeostasis. Whole transcriptomic analysis by microarray indicated that 78 genes had differential expression between the parental strain and its derivative clones. Sixty-one transcripts were up-regulated, while 17 were down-regulated. Based on a collection of single-gene knockout mutants and gene ontology analysis, we suggest that the adaptive response in P. aeruginosa to hyper-salinity relies on multiple gene product interactions.

Conclusions

The individual gene contributions build up the observed phenotype, but do not ease the identification of salinity-related metabolic pathways. The long-term inclusion of P. aeruginosa in salt crystals primes the bacteria, mediating a readjustment of the bacterial physiology to growth in higher salt concentrations. Our findings provide a starting point to understand how P. aeruginosa, a relevant environmental and pathogenic bacterium, survives to long-term salt stress.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1499-2) contains supplementary material, which is available to authorized users.

The use of hair cortisol for the assessment of stress in animals

The hair cortisol concentration (HCC) is assumed to be a retrospective marker of integrated cortisol secretion and stress over longer periods of time. Its quantification is increasingly used in psychoneuroendocrinological studies in humans, but also in animal stress and welfare research. The measurement of HCCs for the assessment of stress offers many considerable benefits for use in domesticated and wild animals, especially due to the easy and minimally invasive sampling procedure and the representation of longer time periods in one sample. This review aims to outline the different fields of application and to assess the applicability and validity of HCC as an indicator for chronic stress or long-term activity of the hypothalamic-pituitary-adrenal axis in wild and domesticated animals. Specific hair characteristics are presented and the advantages and limitations of using HCC are discussed. An overview of findings on the impact of stress- and health-related factors on HCCs and of diverse influencing factors causing variation in hair cortisol levels in different species is given. Recommendations for the use of hair cortisol analysis are proposed and potential fields of future research are pointed out. The studies indicate an effect of age and pregnancy on HCCs, and cortisol incorporation into hair was also found to depend on hair colour, body region, sex and season of year, but these results are less consistent. Furthermore, the results in animals show that a wide array of stressors and pathological conditions alters the cortisol concentrations in hair and that HCC thereby provides a reliable and valid reflection of long-term cortisol secretion in many species. However, more research is necessary to investigate the underlying mechanisms of cortisol incorporation into the hair and to explore the hair growth characteristics in the species of interest. To overcome confounding influences, the use of standardized sampling protocols is strongly advised.

Stress and Perception of Emotional Stimuli: Long-term Stress Rewiring the Brain

Introduction:

Long-term stressful situations can drastically influence one’s mental life. However, the effect of mental stress on recognition of emotional stimuli needs to be explored. In this study, recognition of emotional stimuli in a stressful situation was investigated. Four emotional conditions, including positive and negative states in both low and high levels of arousal were analyzed.

Methods:

Twenty-six healthy right-handed university students were recruited within or after examination period. Participants’ stress conditions were measured using the Perceived Stress Scale-14 (PSS-14). All participants were exposed to some audio-visual emotional stimuli while their brains responses’ were measured using the Electroencephalography (EEG) technique. During the experiment, the subject’s perception of emotional stimuli is evaluated using the Self-Assessment Manikin (SAM) questionnaire. After recording, EEG signatures of emotional states were estimated from connectivity patterns among 8 brain regions. Connectivity patterns were calculated using Phase Slope Index (PSI), Directed Transfer Function (DTF), and Generalized Partial Direct Coherence (GPDC) methods. The EEG-based connectivity features were then labeled with SAM responses. Subsequently, the labeled features were categorized using two different classifiers. Classification accuracy of the system was validated by leave-one-out method.

Results:

As expected, performance of the system is significantly improved by grouping the subjects to stressed and stress-free groups. EEG-based connectivity pattern was influenced by mental stress level.

Conclusion:

Changes in connectivity patterns related to long-term mental stress have overlapped with changes caused by emotional stimuli. Interestingly, these changes are detectable from EEG data in eyes-closed condition.

Field proteomics of Populus alba grown in a heavily modified environment - An example of a tannery waste landfill

Tannery waste is highly toxic and dangerous to living organisms because of the high heavy metal content, especially chromium [Cr(III)]. This study analysed the proteomic response of the Populus alba L. clone 'Villafranca' grown for 4years on a tannery waste landfill. In this extremely hostile environment, the plants struggled with continuous stress, which inhibited growth by 54%, with a 67% decrease in tree height and diameter at breast height compared to those of the forest reference plot, respectively. The leaves and roots of the tannery landfill-grown plants produced strong proteomic stress signals for protection against reactive oxygen species (ROS) and repair to ROS-damaged proteins and DNA as well as signals for protection of the photosynthetic apparatus. The content of HSP80 was also high. However, primary metabolic pathways were generally unaffected, and signals of increased protein protection, but not turnover, were found, indicating mechanisms of adaptation to long-term stress conditions present at the landfill. A proteomic tool, two-dimensional electrophoresis coupled with tandem mass spectrometry, was successfully applied in this environmental in situ study of distant plots (280km apart).

In pregnancy increased maternal STAI trait stress score shows decreased insulin sensitivity and increased stress hormones

INTRODUCTION

Chronic or acute stressors influence maternal and fetal Hypothalamus-Pituitary-Adrenal Axes (HPA) during pregnancy. In this study, the effect of maternal stress into maternal insulin sensitivity was investigated during pregnancy.

MATERIALS AND METHODS

Eighty-two pregnant women [aged 27.1±2.5 (mean±SD) yrs; BMI=25±2.2kg/m²] had at the 2^nd and 3^rd trimesters anthropometry, fasting blood samples (cortisol, Corticotropin Releasing Hormone (CRH), active amylin, Interleukin (IL6)), Oral Glucose Tolerance Test (OGTT) for glucose and insulin, state-trait anxiety inventory (STAI) trait and state questionnaires (for stress assessment).

RESULTS

Maternal cortisol, CRH and STAI state score increased significantly from 2^nd to 3^rd trimester. At these trimesters women with STAI trait scores ≥40 had greater serum cortisol and CRH concentrations and lower insulin sensitivity index (ISI) values than those with scores <40 while STAI trait score predicted negatively ISI. At the 2^nd trimester maternal CRH concentrations correlated positively with maternal STAI state, Homeostatic Model Assessment Insulin Resistance (HOMAR), 1^st and 2^nd phase insulin secretion and negatively with ISI. STAI trait correlated negatively with ISI. STAI state correlated positively with maternal systolic blood pressure and HOMAR. At the 3^rd trimester STAI trait correlated negatively and positively with ISI and STAI state, respectively, while STAI state correlated positively with HOMAR. In women with STAI state scores ≥40, these scores correlated positively with maternal CRH.

CONCLUSIONS

In normal pregnant women, enhanced long-term stress is associated with decreased insulin sensitivity. Both long- and short- term stress are associated with enhanced maternal HPA axis and increased placental CRH secretion.

Comparison of methanol and isopropanol as wash solvents for determination of hair cortisol concentration in grizzly bears and polar bears

Methodological differences among laboratories are recognized as significant sources of variation in quantification of hair cortisol concentration (HCC). An important step in processing hair, particularly when collected from wildlife, is the choice of solvent used to remove or "wash" external hair shaft cortisol prior to quantification of HCC. The present study systematically compared methanol and isopropanol as wash solvents for their efficiency at removing external cortisol without extracting internal hair shaft cortisol in samples collected from free-ranging grizzly bears and polar bears. Cortisol concentrations in solvents and hair were determined in each of one to eight washes of hair with each solvent independently. •There were no significant decreases in internal hair shaft cortisol among all eight washes for either solvent, although methanol removed detectable hair surface cortisol after one wash in grizzly bear hair whereas hair surface cortisol was detected in all eight isopropanol washes.•There were no significant differences in polar bear HCC washed one to eight times with either solvent, but grizzly bear HCC was significantly greater in hair washed with isopropanol compared to methanol.•There were significant differences in HCC quantified using different commercial ELISA kits commonly used for HCC determinations.

Long-term academic stress enhances early processing of facial expressions

Exposure to long-term stress can lead to a variety of emotional and behavioral problems. Although widely investigated, the neural basis of how long-term stress impacts emotional processing in humans remains largely elusive. Using event-related brain potentials (ERPs), we investigated the effects of long-term stress on the neural dynamics of emotionally facial expression processing. Thirty-nine male college students undergoing preparation for a major examination and twenty-one matched controls performed a gender discrimination task for faces displaying angry, happy, and neutral expressions. The results of the Perceived Stress Scale showed that participants in the stress group perceived higher levels of long-term stress relative to the control group. ERP analyses revealed differential effects of long-term stress on two early stages of facial expression processing: 1) long-term stress generally augmented posterior P1 amplitudes to facial stimuli irrespective of expression valence, suggesting that stress can increase sensitization to visual inputs in general, and 2) long-term stress selectively augmented fronto-central P2 amplitudes for angry but not for neutral or positive facial expressions, suggesting that stress may lead to increased attentional prioritization to processing negative emotional stimuli. Together, our findings suggest that long-term stress has profound impacts on the early stages of facial expression processing, with an increase at the very early stage of general information inputs and a subsequent attentional bias toward processing emotionally negative stimuli.

Analysis of hair cortisol levels in captive chimpanzees: Effect of various methods on cortisol stability and variability

Hair cortisol has been reported to be a useful measure of long-term hypothalamic-pituitary-adrenal (HPA) axis activation in several species. It serves as a practical tool for long-term stress assessment, but it is important to understand the methodological factors that can affects hair cortisol assays to avoid methodological artifacts. To that end, we tested several procedures for measuring cortisol levels in hair collected from captive chimpanzees. The results showed that reproducibility was high, and we found no differences in cortisol levels among the various storage, drying, and sampling methods. However, the fineness of homogenized hair, sample weight, and extraction time affected absolute hair cortisol concentration. Although hair cortisol levels were stable over time, factors that may influence measurement results should be kept constant throughout a study.•We modified and validated a methodology involving enzyme immunoassays to reliably measure the hair cortisol levels of captive chimpanzees.•The results revealed that the fineness of homogenized hair, sample weight, and extraction time caused variations in absolute hair cortisol concentrations in chimpanzees. In contrast, storage, drying, and sampling from similar body parts did not affect the results.

Long-term Stress with Hyperglucocorticoidemia-induced Hepatic Steatosis with VLDL Overproduction Is Dependent on both 5-HT2 Receptor and 5-HT Synthesis in Liver

Hepatic triglycerides production and adipose lipolysis are pivotal for long-term stress (LTS) or hyperglucocorticoidemia-induced insulin resistance. 5-hydroxytryptamine (5-HT) has been demonstrated to induce hepatic lipid metabolic abnormality by activating mammalian target of rapamycin (mTOR). In present study, we explored whether 5-HT is involved in LTS effects in liver using restraint stress-exposed rats and cultured primary rat hepatocytes and HepG2 cells. LTS with hyperglucocorticoidemia induced hepatic 5-HT synthetic increase with tryptophan hydroxylase 1 (Tph1) up-regulation, and 5-HT2 receptor (5-HT₂R, including 5-HT2A, 2B receptor) up-regulation in liver and visceral adipose, as well as hepatic mTOR activation with triglycerides and VLDL overproduction with steatosis, and visceral adipose lipolytic increase with high blood free fatty acids (FFAs) level. 5-HT exposure exhibited LTS-like effects in both tissues, and both LTS and 5-HT effects could be abolished significantly by blocking 5-HT₂R. In HepG2 cells dexamethasone or palmitate-induced mTOR activation with triglycerides and VLDL overproduction were accompanied by up-regulations of 5-HT synthesis and 5-HT₂R, which were significantly abolished by gene silencing Tph1 or 5-HT₂R and were almost fully abolished by co-silencing of both, especially on VLDL overproduction. Chemical inhibition of Tph1 or/and 5-HT₂R in both hepatocytes exhibited similar abolishment with genetic inhibition on dexamethason-induced effects. 5-HT-stimulated effects in both hepatocytes were fully abolished by blocking 5-HT₂R, while 5-HT itself also up-regulated 5-HT₂R. In conclusion, up-regulated hepatic 5-HT synthesis and 5-HT₂R induced by both glucocorticoid and FFAs are crucial for LTS-induced hepatic steatosis with VLDL overproduction, while 5-HT by acting on 5-HT₂R mediates mTOR activation in liver.