Effects of interleukin-1 antagonism on cortisol levels in individuals with obesity: a randomized clinical trial

BACKGROUND

Anti-inflammatory treatment with interleukin-1 (IL-1) antagonism decreases both cortisol and adrenocorticotropin hormone (ACTH) levels in individuals with obesity in short term. However, it remains unknown whether these effects persist upon prolonged treatment.

METHODS

In this double-blind, parallel-group trial involving patients with features of the metabolic syndrome, 33 patients were randomly assigned to receive 100 mg of anakinra (recombinant human IL-1 receptor antagonist) subcutaneously twice-daily and 34 patients to receive placebo for 4 weeks. For this analysis, change in cortisol and ACTH levels from baseline to 4 weeks were predefined end points of the trial.

RESULTS

The mean age was 54 years, baseline cortisol levels were 314 nmol/L (IQR 241-385) and C-reactive protein (CRP) levels were 3.4 mg/L (IQR 1.7-4.8). Treatment with anakinra led to a significant decrease in cortisol levels at day 1 when compared to placebo with an adjusted between-group difference of 28 nmol/L (95% CI, -7 to -43; P = 0.03). After 4 weeks, the cortisol-lowering effect of anakinra was attenuated and overall was statistically not significant (P = 0.72). Injection-site reactions occurred in 21 patients receiving anakinra and were associated with higher CRP and cortisol levels.

CONCLUSIONS

IL-1 antagonism decreases cortisol levels in male patients with obesity and chronic low-grade inflammation on the short term. After prolonged treatment, this effect is attenuated, probably due to injection-site reactions (ClinicalTrials.gov, NCT02672592).

Recovery periods during repeated stress impact corticosterone and behavioral responses differently in house sparrows

A number of studies have shown that chronic stress can negatively impact both physiology and behavior in a variety of organisms. What has yet to be extensively explored is whether these changes permanently alter an animal's functioning, or if they can be reversed. In this study, we used wild-caught house sparrows (Passer domesticus) to assess how recovery periods influence the physiological and behavioral impacts of an initial four days and subsequent four days of repeated stressors. Birds were randomly assigned to a recovery group and either experienced 0, 24, or 72 h of recovery between the two sets of stressors (cage rolling and cage tapping). We measured the regulation of the hypothalamic pituitary adrenal (HPA) axis by quantifying baseline and stress-induced corticosterone as well as negative feedback strength. We also assessed behavior using neophobia trials to measure how birds altered their approach towards novel objects and their overall activity. Both behavior and corticosterone responses were assessed before the experiment, after the recovery time, and following the final 4 days of stressors. We found that birds that experienced 24 h of recovery had reduced stress-induced corticosterone, but enhanced negative feedback relative to the pre-experiment sample. Additionally, 4 days of stressors was enough to significantly reduce approach latency towards novel objects; however, pre-experiment levels returned with longer periods of recovery. Finally, recovery time did not significantly influence responses to the second 4 days of stressors. Our results indicate that brief recovery periods partially ameliorate the hormonal and behavioral effects of repeated stress.

The relationship between acute stress and EEG repetition suppression in infants

Over activation of the hypothalamo-pituitary-adrenal (HPA) axis in stress situations is known to influence learning and memory. In adults, an inverted-U shape relationship between acute stress, and learning and memory has been demonstrated. Whether this model fits learning performances in infants is unknown. In this study, we used EEG repetition suppression as physiological measure of learning and salivary cortisol in response to a stressor to investigate the relationship between acute stress and learning in infants. We hypothesized that EEG repetition suppression would be modulated by acute stress following an inverted-U shape relationship. Saliva samples were collected during an EEG experiment before, during and after EEG net installation in 37 healthy infants (18 males) aged between 6 and 26 months. The effect of variation in stress hormones on repetition suppression were modeled using a linear mixed model, with cortisol, age and sex as predictors. Results indicated that in healthy infants, elevations in stress hormones within the normal range are associated with a higher repetition suppression response and an increased response to the first presentation of the stimulus. The later increase could be related to vigilance. Considering that early childhood is a critical period of development, future studies should keep investigating the influence of stress on learning processes in infants.

Neuroendocrine Whiplash: Slamming the Breaks on Anabolic-Androgenic Steroids Following Repetitive Mild Traumatic Brain Injury in Rats May Worsen Outcomes

Sport-related concussion is an increasingly common injury among adolescents, with repetitive mild traumatic brain injuries (RmTBI) being a significant risk factor for long-term neurobiological and psychological consequences. It is not uncommon for younger professional athletes to consume anabolic-androgenic steroids (AAS) in an attempt to enhance their performance, subjecting their hormonally sensitive brains to potential impairment during neurodevelopment. Furthermore, RmTBI produces acute neuroendocrine dysfunction, specifically in the anterior pituitary, disrupting the hypothalamic-pituitary adrenal axis, lowering cortisol secretion that is needed to appropriately respond to injury. Some AAS users exhibit worse symptoms post-RmTBI if they quit their steroid regime. We sought to examine the pathophysiological outcomes associated with the abrupt cessation of the commonly abused AAS, Metandienone (Met) on RmTBI outcomes in rats. Prior to injury, adolescent male rats received either Met or placebo, and exercise. Rats were then administered RmTBIs or sham injuries, followed by steroid and exercise cessation (SEC) or continued treatment. A behavioral battery was conducted to measure outcomes consistent with clinical representations of post-concussion syndrome and chronic AAS exposure, followed by analysis of serum hormone levels, and qRT-PCR for mRNA expression and telomere length. RmTBI increased loss of consciousness and anxiety-like behavior, while also impairing balance and short-term working memory. SEC induced hyperactivity while Met treatment alone increased depressive-like behavior. There were cumulative effects whereby RmTBI and SEC exacerbated anxiety and short-term memory outcomes. mRNA expression in the prefrontal cortex, amygdala, hippocampus, and pituitary were modified in response to Met and SEC. Analysis of telomere length revealed the negative impact of SEC while Met and SEC produced changes in serum levels of testosterone and corticosterone. We identified robust changes in mRNA to serotonergic circuitry, neuroinflammation, and an enhanced stress response. Interestingly, Met treatment promoted glucocorticoid secretion after injury, suggesting that maintained AAS may be more beneficial than abstaining after mTBI.

Sex differences in binge-like EtOH drinking, corticotropin-releasing hormone and corticosterone: effects of β-endorphin

Binge drinking is an increasingly common pattern of risky use associated with numerous health problems, including alcohol use disorders. Because low basal plasma levels of β‐endorphin (β‐E) and an increased β‐E response to alcohol are evident in genetically at‐risk human populations, this peptide is thought to contribute to the susceptibility for disordered drinking. Animal models suggest that the effect of β‐E on consumption may be sex‐dependent. Here, we studied binge‐like EtOH consumption in transgenic mice possessing varying levels of β‐E: wild‐type controls with 100% of the peptide (β‐E +/+), heterozygous mice constitutively modified to possess 50% of wild‐type levels (β‐E +/−) and mice entirely lacking the capacity to synthesize β‐E (−/−). These three genotypes and both sexes were evaluated in a 4‐day, two‐bottle choice, drinking in the dark paradigm with limited access to 20% EtOH. β‐E deficiency determined sexually divergent patterns of drinking in that β‐E −/− female mice drank more than their wild‐type counterparts, an effect not observed in male mice. β‐E −/− female mice also displayed elevated basal anxiety, plasma corticosterone and corticotropin‐releasing hormone mRNA in the extended amygdala, and all of these were normalized by EtOH self‐administration. These data suggest that a heightened risk for excessive EtOH consumption in female mice is related to the drug's ability to ameliorate an overactive anxiety/stress‐like state. Taken together, our study highlights a critical impact of sex on neuropeptide regulation of EtOH consumption.

Repressors exhibit lower cortisol reactivity to group psychosocial stress

Repressors are well-known to monitor potential psychosocial threats to their self-esteem and self-concept. In research, repressors are traditionally categorised as those scoring low on trait anxiety and high on defensiveness (as measured by social desirability scales). Examining repressors' cortisol reactivity to a group socio-evaluative laboratory stressor could be an important way to extend work on the classic 'repressor dissociation', which proposes that this group experience higher levels of physiological stress, but lower levels of subjective affect, during stressful situations. Research however has focused mainly on repressors' higher, more risk-prone levels of autonomic, rather than hypothalamic-pituitary-adrenal (HPA), reactivity to stressful stimuli. We assessed cortisol reactivity using a group-based acute psychosocial stressor, the Trier Social Stress Test for groups (TSST-G), which required participants to individually perform public speaking and mental arithmetic tasks in front of up to six other group members, as well as an evaluative panel of judges. Seventy-seven healthy young females (mean age ± SD: 20.2 ± 3.2 years) took part, of which 64 met the conventional criterion for a response to the TSST-G (<15.5% increase from baseline sample). The Stress-Arousal Checklist was completed pre- and post-TSST-G. Participants also completed the Perceived Stress Scale, the Trait Anxiety Inventory and the Marlow-Crowne Social Desirability Scale. The latter two measures were used to provide a categorisation of repressive coping style. Participants identified as repressive copers exhibited significantly lower cortisol reactivity during the TSST-G. Repressors also self-reported less subjective stress. These findings provide some evidence against the notion of the repressor dissociation and are discussed in terms of how cortisol hyporeactivity may be a pathway through which repressive coping adversely affects health.

Epilepsy, depression, and growth hormone

Depression affects a large proportion of patients with epilepsy, and is likely due in part to biological mechanism. Hormonal dysregulation due to the disruptive effects of seizures and interictal epileptiform discharges on the hypothalamic-pituitary-adrenal axis likely contributes to high rates of depression in epilepsy. This paper reviews the largely unexplored role of neuroendocrine factors in epilepsy-related depression, focusing on Growth Hormone (GH). While GH deficiency is traditionally considered a childhood disorder manifested by impaired skeletal growth, GH deficiency in adulthood is now recognized as a serious disorder characterized by impairments in multiple domains including mood and quality of life. Could high rates of depression in patients with epilepsy relate to subtle GH deficiency? Because GH replacement therapy has been shown to improve mood and quality of life in patients with GH deficiency, this emerging area may hold promise for patients suffering from epilepsy-related depression.

Prenatal maternal stress is associated with lower cortisol and cortisone levels in the first morning urine of 45-month-old children

Prenatal stress (PS) has been related to altered hypothalamic-pituitary-adrenal (HPA) axis activity later in life. So far, studies in children assessing HPA axis functioning have focused on salivary cortisol, reflecting daytime activity. The present work is part of a prospective study and aims to extend knowledge about the association between PS and HPA axis regulation in children. To do so, we investigated cortisol, cortisone, and the ratio cortisone/(cortisone + cortisol) in the first morning urine of 45-month-old children in relation to several measures of maternal stress during pregnancy. Urinary cortisol and cortisone were measured by online turbulent flow chromatography coupled with high performance liquid chromatography-tandem mass spectrometry. PS was defined as: perceived stress for aim 1 (Perceived Stress Scale; n = 280); presence of self-reported (n = 371) and expert-rated psychopathology for aim 2 (Mini International Neuropsychiatric Interview; n = 281); continuous measures of anxiety and depression for exploratory aim 3 (State-Trait Anxiety Inventory and Edinburgh Postnatal Depression Scale; n = 280). Aim 1: Perceived maternal PS showed negative associations with cortisol and cortisone levels. Aim 2: The presence of expert-rated maternal psychopathology was associated with reduced morning cortisone. Aim 3: Continuous measures of anxiety and depression showed negative associations with cortisol and cortisone levels. After correcting for multiple testing, perceived maternal PS (aim 1) and prenatal level of anxiety (aim 3) were significant predictors of children's urinary cortisol and cortisone in the morning (and, in the case of cortisone, also prenatal level of depression). The ratio cortisone/(cortisone + cortisol) as a global marker for the balance between the enzymes metabolizing cortisol to cortisone and vice versa (11β-hydroxysteroid dehydrogenases type 1 and 2; 11β-HSD1 and 2) was not associated with any measure of maternal PS (aims 1-3). The present study provides insight into possible programming effects of PS on nocturnal HPA axis activity and a proxy of 11β-HSD in a large sample. The results suggest that the nocturnal rate of cortisol production is lower in children exposed to PS, but do not support the hypothesis of divergent 11β-HSD activity.

Impact of maltreatment on depressive symptoms in young male adults: The mediating and moderating role of cortisol stress response and coping strategies

BACKGROUND

Converging evidence suggests that maltreated children suffer from depression at an early age and experience recurrent episodes of depression that persist over longer periods of time. However, the stress-related mechanisms hypothesized to be implicated in these associations remain to be specified. The present study tested the mediating and moderating roles of acute cortisol response to stress and coping strategies in the association between child maltreatment and depressive symptoms in early adulthood.

METHODS

Data from 156 men aged 18 to 35 years (n = 56 maltreated) were collected using self-reported questionnaires assessing child maltreatment, depressive symptomatology and coping strategies. Cortisol was measured in response to the "Trier Social Stress Test" (TSST).

RESULTS

Although acute cortisol response to stress did not mediate the maltreatment-depressive symptoms association, a moderation effect was found. Child maltreatment was associated with higher risk of depressive symptoms among participants with a higher cortisol response to stress, but not for those with moderate-to-lower cortisol responses. Additionally, maltreated participants reported more depressive symptoms, an association that was partly explained by their higher use of emotion-oriented coping (mediation). Finally, maltreated individuals who reported using less task-oriented coping had greater depressive symptomatology than those who adopted this coping strategy more frequently (moderation).

CONCLUSION

These findings extend prior work examining the role of the hypothalamic-pituitary-adrenal (HPA) axis in the etiology of depression. The results draw attention to coping strategies, in addition to acute cortisol response to stress, as potential targets for mitigating the onset of depressive symptoms in adults maltreated as children.

Allele-specific DNA methylation level of FKBP5 is associated with post-traumatic stress disorder

BACKGROUND

FK506-binding protein 5 (FKBP5) binds to glucocorticoid receptors and modulates glucocorticoid sensitivity. The FKBP5 gene has been implicated in the dysregulation of human stress responses, contributing to the risk and treatment response of stress-related disorders. The present study examined whether epigenetic changes in FKBP5 are associated with chronic post-traumatic stress disorder (PTSD) status in the context of FKBP5 genetic variation (rs1360780 polymorphism) among male veterans exposed to combat trauma.

METHODS

Korean male veterans who served on active duty during the Vietnam War were categorized into 2 groups: with PTSD (n = 123) and without PTSD (n = 116). The genotype of FKBP5 rs1360780 and DNA methylation levels of two CpG sites at the FKBP5 intron 7 region were assessed in peripheral blood. Analysis of covariance was performed to examine main and interaction effects of PTSD status and FKBP5 genotype on FKBP5 DNA methylation level, with age, trauma levels, and alcohol use as covariates.

RESULTS

A significant main effect of FKBP5 rs1360780 and PTSD and an interaction effect between genotype and PTSD status were found on mean FKBP5 DNA methylation level. The T allele of rs1360780 was associated with lower FKBP5 methylation level. In addition, the PTSD group showed significantly higher methylation than did the non-PTSD group among veterans carrying the risk T allele (n = 96), while no group difference was observed on methylation levels among veterans with the CC genotype (n = 143). Among veterans carrying the T allele, FKBP5 methylation levels were positively correlated with the severity of PTSD symptoms.

CONCLUSIONS

The present study demonstrated different FKBP5 methylation levels in PTSD depending on FKBP5 genetic variation among veterans exposed to combat trauma. The present finding suggests that the genetic and epigenetic modulation of FKBP5 is involved in the pathophysiology of PTSD. Further longitudinal research involving people exposed to trauma is required to understand causal relationships of FKBP5 in the development and recovery of PTSD.

Salience versus magnitude in the measurement of the cortisol awakening response

Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25 h. Aggregated rates revealed a cubic trend, with wave-length of almost exactly 1 h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated. To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, re- analyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered.

Physical Activity versus Psychological Stress: Effects on Salivary Cortisol and Working Memory Performance

Background and Objective: The present study was designed to investigate whether acute physical activity and psychological stress produce different effects on cortisol release and working memory performance. Materials and Methods: Male subjects (N = 12; 18–35 years) were recruited and scheduled to come four times to our lab (within-subject design). For each counterbalanced visit, they performed one of the following four protocols: control, moderate physical activity (MOD), vigorous physical activity (VIG), and acute stress. Heart rate was monitored during every protocol. MOD and VIG were performed for 15 min and were defined as 40–50% and 70–80%, respectively, of their maximum heart rate. Acute stress was imposed via the Trier Social Stress Test (TSST). Salivary samples were collected before and after every protocol to assess cortisol concentrations. Working memory (WM) performance was evaluated through the 2N-Back task right after ending the protocol (early WM) and after a delay of 35 min (late WM). Results: VIG and stress, but not MOD, increased salivary cortisol concentrations. However, the increases of cortisol produced by VIG and stress were not significantly different. Also, there were no significant differences in working memory performance (late and early) in any of the experimental protocols tested. Conclusions: These results show that exercise (VIG) and stress produce similar effects on cortisol release and do not support the hypothesis that working memory capacity is influenced by elevated cortisol levels, either from varying exercise intensities or psychological stress.

Transcriptome analysis of normal-appearing white matter reveals cortisol- and disease-associated gene expression profiles in multiple sclerosis

Inter-individual differences in cortisol production by the hypothalamus–pituitary–adrenal (HPA) axis are thought to contribute to clinical and pathological heterogeneity of multiple sclerosis (MS). At the same time, accumulating evidence indicates that MS pathogenesis may originate in the normal-appearing white matter (NAWM). Therefore, we performed a genome-wide transcriptional analysis, by Agilent microarray, of post-mortem NAWM of 9 control subjects and 18 MS patients to investigate to what extent gene expression reflects disease heterogeneity and HPA-axis activity. Activity of the HPA axis was determined by cortisol levels in cerebrospinal fluid and by numbers of corticotropin-releasing neurons in the hypothalamus, while duration of MS and time to EDSS6 served as indicator of disease severity. Applying weighted gene co-expression network analysis led to the identification of a range of gene modules with highly similar co-expression patterns that strongly correlated with various indicators of HPA-axis activity and/or severity of MS. Interestingly, molecular profiles associated with relatively mild MS and high HPA-axis activity were characterized by increased expression of genes that actively regulate inflammation and by molecules involved in myelination, anti-oxidative mechanism, and neuroprotection. Additionally, group-wise comparisons of gene expression in white matter from control subjects and NAWM from (subpopulations of) MS patients uncovered disease-associated gene expression as well as strongly up- or downregulated genes in patients with relatively benign MS and/or high HPA-axis activity, with many differentially expressed genes being previously undescribed in the context of MS. Overall, the data suggest that HPA-axis activity strongly impacts on molecular mechanisms in NAWM of MS patients, but partly also independently of disease severity.

A Tilted Axis: Maladaptive Inflammation and HPA Axis Dysfunction Contribute to Consequences of TBI

Each year approximately 1.7 million people sustain a traumatic brain injury (TBI) in the US alone. Associated with these head injuries is a high prevalence of neuropsychiatric symptoms including irritability, depression, and anxiety. Neuroinflammation, due in part to microglia, can worsen or even cause neuropsychiatric disorders after TBI. For example, mounting evidence demonstrates that microglia become “primed” or hyper-reactive with an exaggerated pro-inflammatory phenotype following multiple immune challenges. Microglial priming occurs after experimental TBI and correlates with the emergence of depressive-like behavior as well as cognitive dysfunction. Critically, immune challenges are various and include illness, aging, and stress. The collective influence of any combination of these immune challenges shapes the neuroimmune environment and the response to TBI. For example, stress reliably induces inflammation and could therefore be a gateway to altered neuropathology and behavioral decline following TBI. Given the increasing incidence of stress-related psychiatric disorders after TBI, the degree in which stress affects outcome is of particular interest. This review aims to highlight the role of the hypothalamic-pituitary-adrenal (HPA) axis as a key mediator of stress-immune pathway communication following TBI. We will first describe maladaptive neuroinflammation after TBI and how stress contributes to inflammation through both anti- and pro-inflammatory mechanisms. Clinical and experimental data describing HPA-axis dysfunction and consequences of altered stress responses after TBI will be discussed. Lastly, we will review common stress models used after TBI that could better elucidate the relationship between HPA axis dysfunction and maladaptive inflammation following TBI. Together, the studies described in this review suggest that HPA axis dysfunction after brain injury is prevalent and contributes to the dynamic nature of the neuroinflammatory response to brain injury. Experimental stressors that directly engage the HPA axis represent important areas for future research to better define the role of stress-immune pathways in mediating outcome following TBI.

The immediate effects of weaning stress on the hypothalamus-pituitary-adrenal alteration of newly weaned piglets

This study was conducted to examine the effects of weaning stress on gene expression of specific markers in hypothalamus-pituitary-adrenal (HPA) axis and neuronal activity in the newly weaned piglets. Twelve 28-days-old, newly weaned crossbred (Landrace × Yorkshire × Duroc) male piglets from 6 l (2 piglets/l) were randomly categorized into two groups: (a) weaning stress: piglets were separated from their dams, relocated and mixed with the unacquainted domestic piglets for 2 hr (stress, n = 6); (b) no-stress: piglets stayed with their dams in the farrowing house (NS; n = 6). After weaning stress, all piglets were electrically euthanized and the blood samples/HPA tissues were collected for subsequent analysis, including plasma cortisol and mRNA expression of c-fos, c-jun, corticotropin-releasing hormone (CRH), CRH receptor 1 (CRHR-1) and adrenocorticotropin hormone receptor (MC2R). Results: Weaning stress significantly (p < 0.05) increased the plasma cortisol level and suppressed the expression of c-fos and CRH in hypothalamus. In addition, weaning stress enhanced the mRNA abundance of c-jun and CRHR-1 in the pituitary gland. No significant differences in the gene expression of MC2R and CRHR-1 were observed in the adrenal gland between treatment groups. Taken together, HPA involved in weaning stress and CRHR-1 and c-jun could be potential markers to evaluate the activation of HPA axis.

Childhood urbanicity and hair steroid hormone levels in ten-year-old children

BACKGROUND

Research suggests that it may be more stressful for children to grow up in an urban area than in a rural area. Urbanicity may affect physiological stress system functioning as well as the timing of sexual maturation. The purpose of the current study was to investigate whether moderate urbanicity (current and childhood, ranging from rural areas to small cities) was associated with indices of long-term hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axis functioning (cortisol, cortisone, dehydroepiandrosterone and progesterone levels) and whether sex moderated any associations.

METHOD

Children (N = 92) were all 10 years old and from the Dutch general population. Hair samples were collected and single segments (the three cm most proximal to the scalp) were assayed for concentrations of steroid hormones (LCMS/MS method). Neighborhood-level urbanicity and socioeconomic status were measured from birth through age ten years. Analyses were controlled for neighborhood- and family socioeconomic status, body mass index and season of sampling.

RESULTS

The results from multivariate analyses of variance showed no associations between current or childhood moderate urbanicity and hair steroid hormone concentrations. Interaction terms between moderate urbanicity and sex were not statistically significant.

CONCLUSIONS

Associations between urbanicity and steroid hormone levels may only be detectable in highly urban areas and/or during later stages of adolescence. Alternatively, our findings may have been due to most children being from families with a higher socioeconomic status.

Maternal high fat diet programs hypothalamic-pituitary-adrenal function in adult rat offspring

Maternal environmental factors such as diet have profound effects on offspring development and later health. The hypothalamic-pituitary-adrenal (HPA) axis is an important stress neuroendocrine system that is subject to programming by early life challenges. The present study was further to investigate whether maternal high fat diet (HFD) exposure during rat pregnancy and lactation can alter the HPA axis activity in adult male offspring. We observed that maternal HFD consumption exerted long-term effects on the basal activity of the HPA axis in adult offspring, with increased mean plasma corticosterone levels that result from elevated steroid pulse frequence and pulse amplitude. More importantly, maternal HFD offspring displayed enhanced corticosterone responses to restraint (1 h) and lipopolysaccharide (25 μg/kg, iv) but not insulin-induced hypoglycemia (0.3U/kg, iv) stress, suggesting a stressor-specific effect of maternal diet on the hyperresponsiveness of the HPA axis to stress. Additionally, maternal HFD exposure markedly attenuated the habituation of HPA responses to repeated restraint stress. These findings demonstrate that perinatal HFD exposure has a potent and long-lasting influence on development of neuroendocrine regulatory mechanisms. Maternal HFD consumption significantly increased basal corticotropin-releasing factor (CRF) mRNA expression in the paraventricular nucleus; nevertheless, similar increments in CRF mRNA levels following restraint were observed between maternal HFD offspring and control rats. Furthermore, the medial and central nuclei of amygdala played a pivotal role in maternal HFD-induced sensitization of the HPA response to psychological and systemic stress, respectively, suggesting that different neural pathways may mediate maternal HFD-induced HPA hyperresponsivity to different types of stressors. Take together, the long-term effects of maternal HFD challenge on the central regulation of the HPA axis, therefore, expose the adult offspring to greater HPA function throughout lifespan, in stressor-specific and region-specific manner.

Associations between symptoms of depression and anxiety and cortisol responses to and recovery from acute stress

BACKGROUND

Anxiety disorders and major depressive disorder (MDD) have been associated with increased and blunted HPA axis reactivity to social stress. However, research focusing on associations between HPA axis responses to stress and symptoms of anxiety and depression among individuals without a diagnosis remains an understudied area of research.

METHODS

One hundred forty-three adults (52% female) completed the Trier Social Stress Test (TSST). Symptoms of depression and anxiety were assessed prior to the TSST using the anxiety and depression subscales of the Hospital Anxiety and Depression Scale (HADS). HPA axis responses were assessed by measuring salivary cortisol at baseline and following the TSST. Reactivity to and recovery from stress were assessed using multilevel growth modeling controlling for age, BMI, and sex among the full sample and a subset of cortisol responders (n = 72).

RESULTS

Anxiety symptoms were positively associated with flatter recovery slopes among the full sample (t(122.3) = 2.082, p = .039). Among cortisol responders, depression symptoms were associated with steeper reactivity (t(63.32) = 2.53, p = .026) and recovery (t(58.75)=-2.20, p = .03). Anxiety symptoms were associated with marginally flatter reactivity (t(64.00)=-1.97, p = .053) and significantly flatter recovery (t(59.22) = 2.29, p = .025).

CONCLUSION

Symptoms of anxiety and depression among individuals without a psychiatric diagnosis are associated with blunted and exaggerated cortisol responses to and recovery from stress. Such patterns could indicate increased risk for unhealthy HPA axis dysregulation, allostatic load, and disease.

The cortisol awakening response at admission to hospital predicts depression severity after discharge in MDD patients

Major Depressive Disorder (MDD) is associated with hypothalamic-pituitary-adrenal (HPA) axis dysregulation and altered cortisol awakening response (CAR), a non-invasive biomarker for HPA axis reactivity. We theorized that the CAR resembles the accumulated effects of depression over time, and may therefore predict depressive symptom severity once patients return home following inpatient treatment. Two studies are reported. In Study 1 (n = 101; 57% female), the CAR was measured at intake and self-ratings of depression severity was assessed six weeks following discharge. Study 2 (n = 127; 58% female) was a replication and extension of Study 1 where a follow-up assessment of self-rated depression severity was added at six months following discharge. In Study 1 the CAR at intake showed a tendency towards a negative association with self-reported depression six weeks after discharge. Study 2 extended this finding within a more severely depressed, larger sample, where a blunted CAR predicted self-reported depressive severity six weeks and six month following discharge. These findings suggest that a blunted CAR can predict mood deterioration post treatment in inpatients diagnosed with severe MDD.

The physiological significance of the circadian dynamics of the HPA axis: Interplay between circadian rhythms, allostasis and stress resilience

Circadian time-keeping mechanisms preserve homeostasis by synchronizing internal physiology with predictable variations in the environment and temporally organize the activation of physiological signaling mechanisms to promote survival and optimize the allocation of energetic resources. In this paper, we highlight the importance of the robust circadian dynamics of allostatic mediators, with a focus on the hypothalamic-pituitary-adrenal (HPA) axis, for the optimal regulation of host physiology and in enabling organisms to adequately respond and adapt to physiological stressors. We review studies showing how the chronic disruption of circadian rhythms can result in the accumulation of allostatic load, which impacts the appropriate functioning of physiological systems and diminishes the resilience of internal systems to adequately respond to subsequent stressors. A careful consideration of circadian rhythm dynamics leads to a more comprehensive characterization of individual variability in allostatic load and stress resilience. Finally, we suggest that the restoration of circadian rhythms after pathological disruption can enable the re-engagement of allostatic mechanisms and re-establish stress resilience.

Neuroactive Steroids and GABAergic Involvement in the Neuroendocrine Dysfunction Associated With Major Depressive Disorder and Postpartum Depression

Stress and previous adverse life events are well-established risk factors for depression. Further, neuroendocrine disruptions are associated with both major depressive disorder (MDD) and postpartum depression (PPD). However, the mechanisms whereby stress contributes to the underlying neurobiology of depression remains poorly understood. The hypothalamic-pituitary-adrenal (HPA) axis, which mediates the body's neuroendocrine response to stress, is tightly controlled by GABAergic signaling and there is accumulating evidence that GABAergic dysfunction contributes to the impact of stress on depression. GABAergic signaling plays a critical role in the neurobiological effects of stress, not only by tightly controlling the activity of the HPA axis, but also mediating stress effects in stress-related brain regions. Deficits in neuroactive steroids and neurosteroids, some of which are positive allosteric modulators of GABA_A receptors (GABA_ARs), such as allopregnanolone and THDOC, have also been implicated in MDD and PPD, further supporting a role for GABAergic signaling in depression. Alterations in neurosteroid levels and GABAergic signaling are implicated as potential contributing factors to neuroendocrine dysfunction and vulnerability to MDD and PPD. Further, potential novel treatment strategies targeting these proposed underlying neurobiological mechanisms are discussed. The evidence summarized in the current review supports the notion that MDD and PPD are stress-related psychiatric disorders involving neurosteroids and GABAergic dysfunction.

Chronic Glucocorticoid Exposure Induces Depression-Like Phenotype in Rhesus Macaque (Macaca Mulatta)

It has long been observed in humans that the occurrence of depressive symptoms is often accompanied by the dysfunction of hypothalamic-pituitary-adrenal (HPA) axis. The rodent experiments also showed that chronic corticosterone exposure could induce depression-like phenotype. However, rodents are phylogenetically distant from humans. In contrast, non-human primates bear stronger similarities with humans, suggesting research on primates would provide an important complement. For the first time, we investigated the effects of chronic glucocorticoid exposure on rhesus macaques. Seven male macaques were selected and randomized to glucocorticoid or vehicle groups, which were subjected to either prednisolone acetate or saline injections, respectively. The depression-like behaviors were assessed weekly, and the body weights, HPA axis reactivity, sucrose solution consumption and monoaminergic neurotransmitters were further compared between these two groups. The glucocorticoid group was not found to display more depression-like behaviors than the vehicle group until 7 weeks after treatment. Chronic glucocorticoid exposure significantly decreased the levels of cortisol determined from blood (a biomarker for acute HPA axis reactivity) but increased the hair cortisol concentrations (a reliable indicator of chronic HPA axis reactivity) compared with controls. The glucocorticoid group was also found to consume less sucrose solution than controls, a good manifestation of anhedonia. This could be possibly explained by lower dopamine (DA) levels in cerebrospinal fluid induced by chronic glucocorticoid treatment. The results presented here indicate that chronic glucocorticoid exposure could disturb both the acute and chronic HPA axis reactivity, which eventually disturbed the neurotransmitter system and led monkeys to display depression-like phenotype.

Higher trait reappraisal predicts stronger HPA axis habituation to repeated stress

Undergoing stress can be advantageous when it leads to adaptation and growth; however, failure of the hypothalamic-pituitary-adrenal (HPA) axis to habituate (i.e., nonhabituation) involves continuing to become highly activated in response to repeated exposure of the same stimulus and is considered maladaptive. Although 50-75% of individuals assessed in a laboratory exhibit adaptive habituation to repeated stress, variability in habituation suggests psychological processes used in response to stress may play a role, such as emotion regulation (ER). Nonetheless, no research to date has investigated whether ER strategies affect HPA axis habituation. We investigated whether tendency to use two ER strategies, reappraisal and suppression, influenced HPA axis habituation among 84 healthy young adults (60.7% female; M_age = 24.8 years, SD = 6.0) exposed to a standardized experimental stress paradigm on two consecutive days. HPA axis stress responses were assessed using salivary cortisol concentrations. We also examined whether non-manipulated state ER strategies (i.e., those used by the participant during and following the stressor on the first day) modulated HPA axis habituation over and above trait-use in a subsample (N = 60). Trait, but not state, reappraisal was associated with stronger HPA axis habituation. Neither trait nor state suppression were significantly associated with HPA axis habituation. These findings expand our current understanding of how ER can affect stress-related health outcomes and suggest habitual reappraisal plays an important role in adaption of the HPA axis to stress.

Endocrine responses after a single bout of moderate aerobic exercise in healthy adult humans

Exercise is a stress stimulus for the human organism affecting the homeostatic mechanisms of the body, depending on the type, duration, intensity and frequency of exercise. The aim of this study was to determine the effects of a moderate aerobic exercise bout on the Hypothalamo-Pituitary-Adrenal (HPA) axis acute hormonal responses in healthy adult humans. Twelve healthy male and female volunteers (age: 30.6 ± 4.4 years), performed a single bout of a 30-minute aerobic exercise at 70% of VO2max on a treadmill, following standard diet. Blood samples were collected before (t0), at the end of the exercise bout (t30), and 30 min after the completion of exercise (t60). Serum adrenocorticotropic hormone (ACTH), cortisol (COR), aldosterone (ALDO) and renin (REN) were measured. One-way ANOVA was used for statistics. ACTH and COR decreased after exercise, reaching significance (p < 0.01) 30 min after the completion of the exercise bout. ALDO increased at the end of exercise and remained elevated 30 min after its completion. REN significantly increased at the end of exercise (p < 0.05) and remained elevated. The exercise regimen used in this study had beneficial effects on the stress axis, suggesting that specific exercise protocols can be characterised by mild physiological stress-inducing effects hence be prescribed for special diseased populations.