Cortisol Awakening Response as a Prospective Risk Factor for Depressive Symptoms in Women After Treatment for Breast Cancer

OBJECTIVE

The aim of the study was to investigate hypothalamic-pituitary-adrenal axis (HPA axis) functioning as a neurobiological risk factor for depressive symptoms in an ongoing longitudinal, observational study of women undergoing treatment and recovery from breast cancer. Many women with breast cancer experience depressive symptoms that interfere with their treatment, recovery, and quality of life. Psychosocial risk factors for depression among patients with cancer and survivors have been identified, yet neurobiological risk factors in this population remain largely unexamined.

METHODS

Women recently diagnosed with early-stage breast cancer (N = 135) were enrolled before starting neoadjuvant/adjuvant treatment (radiation, chemotherapy, endocrine therapy). At baseline, participants collected saliva samples to measure diurnal HPA axis functioning for 3 days: at waking, 30 minutes after waking, 8 hours after waking, and bedtime. Participants also completed a standardized measure of depressive symptoms (Center for Epidemiological Studies-Depression Scale) at baseline and 6 months after completion of primary treatment. Multivariate regression was used to predict continuous depressive symptoms at 6-month posttreatment from continuous depressive symptoms at baseline, cortisol awakening response (CAR), and other measures of diurnal HPA axis functioning.

RESULTS

The magnitude of CAR predicted changes in depressive symptoms over time, such that women with a higher CAR showed a greater increase from baseline to 6-month posttreatment (b = 5.67, p = .023). Diurnal slope and total cortisol output were not associated with concurrent depressive symptoms or their change over time.

CONCLUSIONS

Elevated CAR may be a neurobiological risk factor for increases in depressive symptoms in the months after breast cancer treatment and warrants further investigation.

Neurosteroid, GABAergic and hypothalamic pituitary adrenal (HPA) axis regulation: what is the current state of knowledge in humans?

RATIONALE

A robust epidemiological literature suggests an association between chronic stress and the development of affective disorders. However, the precise biological underpinnings of this relationship remain elusive. Central to the human response and adaptation to stress, activation and inhibition of the hypothalamic pituitary adrenal (HPA) axis involves a multi-level, multi-system, neurobiological stress response which is as comprehensive in its complexity as it is precarious. Dysregulation in this complex system has implications for human stress related illness.

OBJECTIVES

The pioneering research of Robert Purdy and colleagues has laid the groundwork for advancing our understanding of HPA axis regulation by stress-derived steroid hormones and their neuroactive metabolites (termed neurosteroids), which are potent allosteric modulators of GABAA receptor function in the central nervous system. This review will describe what is known about neurosteroid modulation of the HPA axis in response to both acute and chronic stress, particularly with respect to the current state of our knowledge of this process in humans.

RESULTS

Implications of this research to the development of human stress-related illness are discussed in the context of two human stress-related psychiatric disorders - major depressive disorder and premenstrual dysphoric disorder.

CONCLUSIONS

Neurosteroid-mediated HPA axis dysregulation is a potential pathophysiologic mechanism which may cross traditional psychiatric diagnostic classifications. Future research directions are identified.

Environmental stressors and epigenetic control of the hypothalamic-pituitary-adrenal axis

In this review, we provide a brief summary of several key studies that broaden our understanding of stress and its epigenetic control of the function and behavior of the hypothalamic-pituitary-adrenal (HPA) axis. Clinical and animal studies suggest a link among exposure to stress, dysregulation of the HPA axis, and susceptibility to neuropsychiatric illnesses. Recent studies have supported the notion that exposure to glucocorticoids and stress in various forms, durations, and intensities during different periods of development leads to long-lasting maladaptive HPA axis response in the brain. They demonstrate that this maladaptive response is comprised of persistent epigenetic changes in the function of HPA axis-associated genes that govern homeostatic levels of glucocorticoids. Stressors and/or disruption of glucocorticoid dynamics also target genes such as brain-derived neurotrophic factor(BDNF) and tyrosine hydroxylase(TH) that are important for neuronal function and behavior. While a definitive role for epigenetic mechanisms remains unclear, these emerging studies implicate glucocorticoid signaling and its ability to alter the epigenetic landscape as one of the key mechanisms that alter the function of the HPA axis and its associated cascades. We also suggest some of the requisite studies and techniques that are important, such as additional candidate gene approaches, genome-wide epigenomic screens, and innovative functional and behavioral studies, in order to further explore and define the relationship between epigenetics and HPA axis biology. Additional studies examining stress-induced epigenetic changes of HPA axis genes, aided by innovative techniques and methodologies, are needed to advance our understanding of this relationship and lead to better preventive, diagnostic, and corrective measures.

The effectiveness of aerobic training, cognitive behavioural therapy, and energy conservation management in treating MS-related fatigue: the design of the TREFAMS-ACE programme

BACKGROUND

TREFAMS is an acronym for TReating FAtigue in Multiple Sclerosis, while ACE refers to the rehabilitation treatment methods under study, that is, Aerobic training, Cognitive behavioural therapy, and Energy conservation management. The TREFAMS-ACE research programme consists of four studies and has two main objectives: (1) to assess the effectiveness of three different rehabilitation treatment strategies in reducing fatigue and improving societal participation in patients with MS; and (2) to study the neurobiological mechanisms of action that underlie treatment effects and MS-related fatigue in general.

METHODS/DESIGN

Ambulatory patients (n = 270) suffering from MS-related fatigue will be recruited to three single-blinded randomised clinical trials (RCTs). In each RCT, 90 patients will be randomly allocated to the trial-specific intervention or to a low-intensity intervention that is the same for all RCTs. This low-intensity intervention consists of three individual consultations with a specialised MS-nurse. The trial-specific interventions are Aerobic Training, Cognitive Behavioural Therapy, and Energy Conservation Management. These interventions consist of 12 individual therapist-supervised sessions with additional intervention-specific home exercises. The therapy period lasts 16 weeks. All RCTs have the same design and the same primary outcome measures: fatigue - measured with the Checklist Individual Strength, and participation - measured with the Impact on Participation and Autonomy questionnaire. Outcomes will be assessed 1 week prior to, and at 0, 8, 16, 26 and 52 weeks after randomisation. The assessors will be blinded to allocation. Pro- and anti-inflammatory cytokines in serum, salivary cortisol, physical fitness, physical activity, coping, self-efficacy, illness cognitions and other determinants will be longitudinally measured in order to study the neurobiological mechanisms of action.

DISCUSSION

The TREFAMS-ACE programme is unique in its aim to assess the effectiveness of three rehabilitation treatments. The programme will provide important insights regarding the most effective treatment for MS-related fatigue and the mechanisms that underlie treatment response. A major strength of the programme is that the design involves three almost identical RCTs, enabling a close comparison of the treatment strategies and a strong overall meta-analysis. The results will also support clinical practice guidelines for the treatment of MS-related fatigue.

TRIAL REGISTRATIONS

Current Controlled Trials ISRCTN69520623, ISRCTN58583714, and ISRCTN82353628.

Pervasive alterations of emotional and neuroendocrine responses to an acute stressor after neonatal amygdala lesions in rhesus monkeys

The current study examined the long-term effects of neonatal amygdala lesions on emotional and hypothalamic-pituitary-adrenal (HPA) axis reactivity to an acute stressor in rhesus monkeys. Rhesus monkeys received either bilateral MRI-guided ibotenic acid amygdala (Neo-Aibo; n=6) or sham (Neo-C; n=7) lesions between 7 and 14 days of age. Emotional reactivity was assessed using the Human Intruder paradigm at 2 months, 4.5 months, and 6-8 years of age, whereas stress neuroendocrine response was only assessed in adulthood (6-8 years). The modulation of defensive and emotional behaviors based on the gaze direction of the intruder emerged between 2 and 4 months of age in surrogate-peer reared sham-operated infant monkeys, as already shown for mother-reared infants. Although neonatal amygdala lesions did not impair the ability to exhibit defensive and emotional behaviors, it altered the modulation of these responses based on the intruder's gaze direction. The changes in emotional reactivity after neonatal amygdala lesions emerged in infancy and persisted throughout adulthood when they were associated with a reduction of basal cortisol levels and a blunted cortisol response to the stressor. These changes are reminiscent of those found after adult-onset amygdala lesions, demonstrating little functional compensation following early amygdala damage.

The role of cortisol and psychopathy in the cycle of violence

RATIONALE

Child abuse and neglect are universal risk factors for delinquency, violence, and aggression; this phenomenon is known as the cycle of violence. Additional factors-psychopathy, impulsiveness, and disruptions in the hypothalamic-pituitary-adrenal (HPA) axis-play a role in aggressive behavior but have rarely been examined in the same conceptual and experimental framework.

OBJECTIVES

We sought to examine the above-mentioned risk factors for aggression in a prospective study employing psychopharmacologic and psychometric techniques.

METHODS

Sixty-seven adult participants were given an acute dose of 20 mg cortisol in a placebo-controlled, within-subject, counter-balanced dosing design. Salivary cortisol was measured at baseline and at regular intervals across a 5 h testing period. Following dosing, state-aggressive behavior was measured by a laboratory task, the Point-Subtraction Aggression Paradigm. History of child abuse/neglect, psychopathy, impulsivity, and a trait measure of aggression were assessed through self-report questionnaires.

RESULTS

Using multiple regression, a model including abuse/neglect, psychopathy, impulsivity, and baseline cortisol explained 58 % of the variance in trait aggression and 26 % of the variance in state aggression. Abuse/neglect predicted diminished HPA-axis reactivity and HPA-axis reactivity showed a trend toward predicting state and trait aggression, although it was not a significant mediating variable between abuse/neglect and aggression.

CONCLUSIONS

The results indicate that child maltreatment, psychopathy and HPA-axis reactivity interact to provide a confluence over aggressive behavior, and intervention efforts need to consider all these factors.

Corticosterone metabolism by chicken follicle cells does not affect ovarian reproductive hormone synthesis in vitro

Glucocorticoids affect reproductive hormone production in many species. In chickens, elevated plasma corticosterone down-regulates testosterone and progesterone concentrations in plasma, but also in egg yolk. This suppression could be mediated via the hypothalamic-pituitary system but also via local inhibition of gonadal activity by glucocorticoids. As the latter has not been tested in birds yet, we tested if corticosterone directly inhibits ovarian steroid synthesis under in vitro conditions. We hypothesized that degradation of corticosterone by follicular cells impairs their ability to synthesize reproductive hormones due to either inhibition of enzymes or competition for common co-factors. Therefore, we first established whether follicles degrade corticosterone. Follicular tissue was harvested from freshly euthanized laying hens and incubated with radiolabelled corticosterone. Radioactive metabolites were visualized and quantified by autoradiography. Follicles converted corticosterone in a time-dependent manner into metabolites with a higher polarity than corticosterone. The predominant metabolite co-eluted with 20β-dihydrocorticosterone. Other chicken tissues mostly formed the same metabolite when incubated with corticosterone. In a second experiment, follicles were incubated with either progesterone or dehydroepiandrosterone. Corticosterone was added in increasing dosages up to 1000 ng per ml medium. Corticosterone did not inhibit the conversion of progesterone and dehydroepiandrosterone into a number of different metabolites, including 17α-hydroxyprogesterone, androstenedione and testosterone. In conclusion, avian tissues degrade corticosterone mostly to 20β-dihydrocorticosterone and even high corticosterone dosages do not affect follicular hormone production under in vitro conditions.

The Hypothalamic-Pituitary-Adrenal Axis, Obesity, and Chronic Stress Exposure: Sleep and the HPA Axis in Obesity

Obesity, exposure to stress and inadequate sleep are prevalent phenomena in modern society. In this review we focus on their relationships and critically evaluate causality. In obese individuals, one of the main stress systems, the hypothalamic-pituitary-adrenal axis, is altered, and concentrations of cortisol are elevated in adipose tissue due to elevated local activity of 11β-hydroxysteroid dehydrogenase (HSD) type 1. Short sleep and decreased sleep quality are also associated with obesity. In addition, experimental sleep curtailment induces HPA-axis alterations which, in turn, may negatively affect sleep. These findings implicate that obesity, stress and sleep loss are all related in a vicious circle. Finally, we discuss new strategies to combat obesity through modulating cortisol levels in adipose tissue by 11β-HSD(1) inhibitors or by improving sleep duration.

Associations of long-term shift work with waking salivary cortisol concentration and patterns among police officers

The objective of this study was to evaluate whether long-term shift work is associated with both the total hormonal secretion after awakening and the pattern of the cortisol levels during the first hour following awakening, among 65 randomly selected police officers who represent a high stress occupation. Dominant shift (Day, Afternoon, or Midnight) was ascertained using daily payroll records of each participant's work activities during the 6-8 yrs prior to saliva sampling. Four salivary samples were collected at 15 min intervals upon first awakening. After accounting for potential confounders, salivary cortisol concentrations averaged across all four time points and total area under the curve differed significantly across shift with midnight shift workers showing suppressed awakening cortisol response relative to the afternoon and day shift. The percent of hours worked on midnight shift was inversely correlated with total awakening cortisol output. In contrast, the pattern of cortisol secretion during the first hour following waking appeared not to be affected as no significant interaction effect was found between time since awakening and shift work. The results show that long-term midnight shift work is associated with decreased absolute mean level and total volume of cortisol released over the waking period.

Stress-induced activation of the HPA axis predicts connectivity between subgenual cingulate and salience network during rest in adolescents

BACKGROUND

Responses to stress vary greatly in young adolescents, and little is known about neural correlates of the stress response in youth. The purpose of this study was to examine whether variability in cortisol responsivity following a social stress test in young adolescents is associated with altered neural functional connectivity (FC) of the salience network (SN) measured during resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

Forty-nine typically developing young adolescents participated in a social stress test during which they contributed salivary cortisol samples. Following this, they underwent rs-fMRI scanning. We examined the association of FC of the SN [composed of anterior cingulate cortex and bilateral anterior insula regions] with cortisol responsivity.

RESULTS

Greater cortisol responsivity was significantly positively correlated with higher FC between subgenual anterior cingulate cortex (Cg25) and the SN, controlling for participant age. There were no regions of the brain that showed an inverse relation.

CONCLUSIONS

Brain systems that have been implicated in autonomic arousal and that influence subjective feeling states show altered FC associated with stress responsivity in early life.

Stress decreases the ability to resist smoking and potentiates smoking intensity and reward

We have developed a novel human laboratory model to examine two primary aspects of stress-precipitated tobacco relapse: (1) Does stress reduce the ability to resist the first cigarette? (2) Once the first cigarette is initiated, does stress facilitate subsequent smoking? Using a within-subject design, daily smokers (n = 37) who were nicotine deprived overnight received a personalized imagery induction (stress or neutral) on two separate days, and then had the option of initiating a tobacco self-administration session or delaying initiation for up to 50 min in exchange for three levels of monetary reinforcement. Subsequently, the tobacco self-administration session entailed a 1-hour period in which subjects could choose to smoke using a smoking topography system. Following the stress induction, subjects were less able to resist smoking, smoked more intensely (increased puffs, shorter inter-puff interval, and greater peak puff velocity), and perceived greater satisfaction and reward from smoking. Stress significantly increased hypothalamus-pituitary-adrenal (HPA) axis reactivity, tobacco craving, negative emotion, and physiologic reactivity relative to the neutral condition. In addition, increased cortisol, ACTH, and tobacco craving were associated with reduced ability to resist smoking following stress. These findings have implications for understanding the impact of stress on smoking relapse and model development to assess smoking lapse behavior.

Corticosterone pretreatment suppresses stress-induced hypothalamic-pituitary-adrenal axis activity via multiple actions that vary with time, site of action, and de novo protein synthesis

Glucocorticoid regulation of the hypothalamic-pituitary-adrenal (HPA) axis is believed to depend on multiple actions operative within discrete time domains. However, the underlying cellular and molecular mechanisms for those glucocorticoid actions remain undetermined. Moreover, there is absence of in vivo studies examining whether there are multiple glucocorticoid effects on HPA axis-related function within an intermediate feedback time frame (1-3  h after glucocorticoid elevation), and whether those effects depend on de novo protein synthesis. We examined in rats the effects of protein synthesis inhibition on HPA axis response to restraint (15 min) after 1 and 3  h phasic corticosterone (CORT) pretreatment. We measured HPA axis hormones (ACTH and CORT) and gene expression in the paraventricular nucleus (c-fos and crh genes), as well as gene expression in the anterior and intermediate pituitaries (c-fos and pomc genes). Both CORT pretreatment intervals produced inhibition of stress-induced ACTH secretion, but no inhibition was observed in the presence of protein synthesis inhibition. CORT pretreatment produced inhibitory effects on stress-induced gene expression that varied for each gene depending on the anatomical site, pretreatment time, and protein synthesis dependency. Taken together, the ACTH and gene expression patterns support the presence of multiple independent glucocorticoid actions initiated during the intermediate glucocorticoid negative feedback phase. Moreover, we conclude that those effects are exerted predominantly on the intrinsic anatomical elements of the HPA axis, and some of those effects depend on CORT induction of the expression of one or more regulatory gene products.

Increased waking salivary cortisol and depression risk in preschoolers: the role of maternal history of melancholic depression and early child temperament

BACKGROUND

Elevated morning cortisol is a prospective predictor of major depression and may serve as a vulnerability marker. We examined the relation between morning cortisol and two prominent risk factors for depression in preschool-aged children: maternal depression and child temperament. We also explored whether maternal depression during the child's life, parental hostility and life stress explained these associations.

METHODS

Ninety-four children provided a morning salivary cortisol sample, and 92 children provided an evening sample. Child temperament and parenting were assessed using observational measures, and maternal depression and life stress were assessed with clinical interviews.

RESULTS

Maternal history of melancholic depression and child temperamental low positive emotionality were significantly associated with higher morning cortisol. These relations persisted after controlling for children's negative emotionality and concurrent depressive symptoms, parental hostility, and life stress.

CONCLUSIONS

Our findings support the hypothesis that elevated morning cortisol may serve as an early-emerging vulnerability factor for depression, and highlight the importance of anhedonia in risk for depression.

A general enhancement of autonomic and cortisol responses during social evaluative threat

OBJECTIVE

To examine the Social Self Preservation Theory, which predicts that stressors involving social evaluative threat (SET) characteristically activate the hypothalamic-pituitary-adrenal (HPA) axis. The idea that distinct psychosocial factors may underlie specific patterns of neuroendocrine stress responses has been a topic of recurrent debate.

METHODS

Sixty-one healthy university students (n = 31 females) performed a challenging speech task in one of three conditions that aimed to impose increasing levels of SET: performing the task alone (no social evaluation), with one evaluating observer, or with four evaluating observers. Indices of sympathetic (preejection period) and parasympathetic (heart rate variability) cardiac drive were obtained by impedance- and electrocardiography. Salivary cortisol was used to index HPA activity. Questionnaires assessed affective responses.

RESULTS

Affective responses (shame/embarrassment, anxiety, negative affect, and self-esteem), cortisol, heart rate, sympathetic and parasympathetic activation all differentiated evaluative from nonevaluative task conditions (p < .001). The largest effect sizes were observed for cardiac autonomic responses. Physiological reactivity increased in parallel with increasing audience size (p < .001). An increase in cortisol was predicted by sympathetic activation during the task (p < .001), but not by affective responses.

CONCLUSION

It would seem that SET determines the magnitude, rather than the pattern, of physiological activation. This potential to perturb broadly multiple physiological systems may help explain why social stress has been associated with a range of health outcomes. We propose a threshold-activation model as a physiological explanation for why engaging stressors, such as those involving social evaluation or uncontrollability, may seem to induce selectively cortisol release.

Hypothalamic-pituitary-adrenal axis dysregulation in depressed children and adolescents: a meta-analysis

Research findings on the hypothalamic-pituitary-adrenal (HPA) axis and pediatric depression reflect a variety of methodological approaches that tap different facets of HPA-axis functions. Partly owing to the methodological heterogeneity of studies, descriptive reviews of this area have produced inconsistent conclusions. Therefore, we conducted formal meta-analyses of pertinent studies in order to advance our understanding of HPA-axis dysregulation in pediatric depression. We examined: (a) 17 published studies of HPA-axis response to the dexamethasone suppression test (DST) in depressed youth (DST; N=926) and (b) 17 studies of basal HPA-axis functioning (N=1332). We also examined descriptively studies that used corticotropin-releasing hormone (CRH) infusion, and those that used psychological probes of the HPA-axis. The global standardized mean effect size difference in HPA-axis response to the DST between depressed and non-depressed youth was 0.57, z=4.18, p<0.01. The global standardized mean difference effect size in basal HPA-axis functioning was 0.20, z=4.53, p<0.01. Age, sex, timing of sampling, dexamethasone dosage, or type of control group was not a significant source of variability for the DST or basal studies. In addition, when compared to non-depressed peers, depressed youth have a normative response to CRH infusion but an overactive response to psychological stressors. In conclusion, the HPA-axis system tends to be dysregulated in depressed youth, as evidenced by atypical responses to the DST, higher baseline cortisol values, and an overactive response to psychological stressors. This pattern of dysregulation suggests anomalies within the axis's negative feedback system and CRH production, but intact pituitary and adrenal sensitivity.

Serotonin transporter polymorphism predicts waking cortisol in young girls

Major Depressive Disorder (MDD) is one of the most prevalent and costly of all psychiatric disorders. The hypothalamic pituitary adrenal (HPA)-axis, which regulates the hormonal response to stress, has been found to be disrupted in depression. HPA dysregulation may represent an important risk factor for depression. To examine a possible genetic underpinning of this risk factor without the confound of current or lifetime depression, we genotyped 84 never-disordered young girls, over a third of whom were at elevated risk for depression, to assess the association between a polymorphism in the promoter region of the serotonin transporter (5-HTT) gene and diurnal variation in HPA-axis activity. This 5-HTT-linked polymorphic region (5-HTTLPR) has been previously found to interact with stress to increase risk for depression. We found 5-HTTLPR to be significantly associated with diurnal cortisol levels: girls who were homozygous for the short-allele had higher levels of waking (but not afternoon or evening) cortisol than did their long-allele counterparts. This finding suggests that genetic susceptibility to HPA-axis dysregulation, especially apparent in levels of waking cortisol, is detectable in individuals as young as 9 years of age.

Benefits of family reunions: social support in secondary greylag goose families

Social interactions are among the most potent stressors. However, social allies may diminish stress, increase success in agonistic encounters and ease access to resources. We studied the role of social support as a major mechanism for individual stress management in families of free-ranging greylag geese (Anser anser). Greylag geese are long-term monogamous, live in a female-bonded social system, and fledged offspring stay with their parents until the next breeding season ('primary families'). Should parents then fail to fledge young, subadults might rejoin them in summer after molt is completed ('secondary families'). We have previously shown that primary greylag goose families reap benefits from active social support in agonistic encounters, and also excrete lower levels of immuno-reactive corticosterone metabolites (CORT, 'passive social support'). Here we investigated how far active and passive social support continues in secondary goose families. Although we found that active support in agonistic encounters was almost absent in secondary families, subadult male geese won an increased number of agonistic encounters due to the mere presence of their secondary family. Particularly adult and subadult females benefited from passive social support through decreased CORT, whereas males did not. Decrease in the hormonal stress response during challenging situations, induced by social allies, may help the females' long-term energy management, thereby improving the odds for successful future reproduction. We discuss whether joining a secondary family may be an alternative tactic for young geese towards optimizing their start into a complex social life.

Night eating status and influence on body weight, body image, hunger, and cortisol pre- and post- Roux-en-Y Gastric Bypass (RYGB) surgery

Night Eating Syndrome is a common disorder in severely obese individuals and may be associated with hypothalamic pituitary adrenal (HPA) axis dysregulation. This study compared night eaters (NE) and comparably obese controls (C) pre- and post-Roux-en- Y Gastric Bypass surgery at 2 and 5 months, following an overnight fast on hormonal measures associated with HPA axis and related appetite and psychological measures. There were 24 (10 NE, 14 C) clinically severely obese participants (body mass index =47.0+/-8.4 SD). At pre-surgery baseline, afternoon fasting hunger ratings differed significantly and were lower for NE than for C (p=0.01). Eight of the participants (4 NE, 4C) returned for all 3 study visits. At 5 months post-surgery, NE and C did not differ in weight loss, reductions in waist circumference, insulin levels, and insulin resistance (homeostasis model assessment). However, NE as compared to C, did not improve in self ratings of body image (p<0.05), and had significant increases in fasting afternoon cortisol levels 5 months after surgery (p=0.01).

Chronic voluntary wheel running facilitates corticosterone response habituation to repeated audiogenic stress exposure in male rats

Voluntary exercise is associated with the prevention and treatment of numerous physical and psychological illnesses, yet the mechanisms by which it confers this protection remain unclear. In contrast, stress, particularly under conditions of prolonged or repeated exposure when glucocorticoid levels are consistently elevated, can have a devastating impact on health. It has been suggested that the benefits of physical exercise may lie in an ability to reduce some of the more deleterious health effects of stress and stress hormones. The present series of experiments provides evidence that voluntary exercise facilitates habituation of corticosterone but not adrenocorticotropin hormone responses to repeated stress presentations. After 6 weeks of running wheel access or sedentary housing conditions, rats were exposed to 11 consecutive daily 30 min presentations of 98 dB noise stress. Similar corticosterone responses in exercised rats and sedentary controls were observed following the first, acute stress presentation. While both groups demonstrated habituation of corticosterone secretory responses with repeated noise stress exposures, the rate of habituation was significantly facilitated in exercised animals. These results suggest that voluntary exercise may reduce the negative impact of prolonged or repeated stress on health by enhancing habituation of the corticosterone response ultimately reducing the amount of glucocorticoids the body and brain are exposed to.

Effects of interferon-alpha on rhesus monkeys: a nonhuman primate model of cytokine-induced depression

BACKGROUND

Interferon (IFN)-alpha is an innate immune cytokine that causes high rates of depression in humans and therefore has been used to study the impact of cytokines on the brain and behavior. To establish a nonhuman primate model of cytokine-induced depression, we examined the effects of IFN-alpha on rhesus monkeys.

METHODS

Eight rhesus monkeys were administered recombinant human (rHu)-IFN-alpha (20 MIU/m(2)) or saline for 4 weeks in counterbalanced fashion, and videotaped behavior, as well as plasma and cerebrospinal fluid (CSF), were obtained at regular intervals to assess behavioral, neuroendocrine, immune, and neurotransmitter parameters. Additionally, expression and activity of IFN-alpha/beta receptors in monkey peripheral blood mononuclear cells (PBMCs) were assessed.

RESULTS

Compared with saline treatment, IFN-alpha administration was associated with persistent increases in anxiety-like behaviors and decreases in environmental exploration. In addition, IFN-alpha induced significant increases in plasma concentrations of corticotropin (ACTH), cortisol, and interleukin-6 that tended to diminish after chronic administration, especially in dominant animals. Interestingly, in three animals, depressive-like, huddling behavior was observed. Monkeys that displayed huddling behavior exhibited significantly higher plasma concentrations of ACTH and lower CSF concentrations of the dopamine metabolite homovanillic acid. Rhesus monkey PBMCs were found to express mRNA and protein for the IFN-alpha/beta receptor. Moreover, treatment of PBMCs with rHu-IFN-alpha led to induction of STAT1, one of the primary IFN-alpha-induced signaling molecules.

CONCLUSIONS

IFN-alpha evoked behavioral, neuroendocrine, and immune responses in rhesus monkeys that are similar to humans. Moreover, alterations in hypothalamic-pituitary-adrenal axis responses and dopamine metabolism may contribute to IFN-alpha-induced depressive-like huddling behavior.

Distinct patterns of neural activation associated with ethanol seeking: effects of naltrexone

BACKGROUND

Alcoholism, like other substance abuse disorders, is a chronically relapsing condition. Compared with other abused drugs, however, little is known about the neural mechanisms mediating ethanol (EtOH)-craving and -seeking behavior leading to relapse. This study, therefore, was conducted to identify candidate brain regions that are recruited by an EtOH-associated contextual stimulus (S(+)). A secondary objective was to determine whether EtOH S(+)-elicited neural recruitment patterns are modified by the opiate antagonist naltrexone (NTX), a compound that reduces cue-induced craving in alcoholics and attenuates ethanol seeking in animal models of relapse.

METHODS

Rats were tested in a conditioned reinstatement model of relapse with subsequent examination of brain c-fos expression patterns elicited by an EtOH S(+) versus a cue associated with nonreward (S(-)). In addition, modification of these expression patterns by NTX was examined.

RESULTS

The EtOH S(+) reinstated extinguished responding and increased c-fos expression within the prefrontal cortex, hippocampus, nucleus accumbens, and hypothalamic paraventricular nucleus (PVN). Naltrexone suppressed the S(+)-induced reinstatement and attenuated hippocampal CA3 c-fos expression, while increasing neural activity in the extended amygdala and PVN.

CONCLUSIONS

Ethanol-associated contextual stimuli recruit key brain regions that regulate associative learning, goal-directed behavior, and Pavlovian conditioning of emotional significance to previously neutral stimuli. In addition, the data implicate the hippocampus, amygdala, and PVN as potential substrates for the inhibitory effects of NTX on conditioned reinstatement.

Hypercortisolemic depression is associated with the metabolic syndrome in late-life

INTRODUCTION

Depression has been hypothesized to be associated with metabolic abnormalities which increase the risk of cardiovascular disease (CVD) and diabetes. Such a link could be due to increased HPA-axis activity. This study investigates the cross-sectional relationship between depression, urinary cortisol and metabolic syndrome in an older population.

METHODS

Data are from 867 participants of the InChianti Study, aged 65 years. Depressive symptoms were assessed using the CES-D scale; cortisol levels were determined in 24-h urine samples. Metabolic syndrome was defined as three or more of the following: abdominal obesity, high triglycerides, low HDL cholesterol, high blood pressure, and high fasting glucose.

RESULTS

Clinically relevant depressed mood (CES-D20) was present in 20.6% of the sample, and 24.5% had the metabolic syndrome. After adjustment for sociodemographics and health indicators, depression score (per SD increase: OR=1.20, 95% CI=1.02-1.41) and urinary cortisol level (per SD increase: OR=1.23, 95% CI=1.01-1.51) were significantly associated with presence of metabolic syndrome. There was, however, a significant interaction (p=0.003) between depressed mood and urinary cortisol in the probability of having metabolic syndrome. The odds of metabolic syndrome in persons with both depressed mood and urinary cortisol excretion in the highest tertile was 1.84 (95% CI=1.02-3.34) compared to persons with neither condition.

DISCUSSION

This study suggests a synergistic relationship between depression, cortisol and metabolic syndrome. Hypercortisolemic depression may constitute a specific risk group for the metabolic syndrome.

Cortisol, contingency learning, and memory in preterm and full-term infants

Cortisol plays an important role in learning and memory. An inverted-U shaped function has been proposed to account for the positive and negative effects of cortisol on cognitive performance and memory in adults, such that too little or too much impair but moderate amounts facilitate performance. Whether such relationships between cortisol and mental function apply to early infancy, when cortisol secretion, learning, and memory undergo rapid developmental changes, is unknown. We compared relationships between learning/memory and cortisol in preterm and full-term infants and examined whether a greater risk for adrenal insufficiency associated with prematurity produces differential cortisol-memory relationships. Learning in three-month old (corrected for gestational age) preterm and full-term infants was evaluated using a conjugate reinforcement mobile task. Memory was tested by repeating the same task 24h later. Salivary cortisol samples were collected before and 20 min after the presentation of the mobile. We found that preterm infants had lower cortisol levels and smaller cortisol responses than full-term infants. This is consistent with relative adrenal insufficiency reported in the neonatal period. Infants who showed increased cortisol levels from 0 to 20 min on Day 1 had significantly better memory, regardless of prematurity, than infants who showed decreased cortisol levels.

Flow cytometric determination of glucocorticoid receptor (GCR) expression in lymphocyte subpopulations: lower quantity of GCR in patients with post-traumatic stress disorder (PTSD)

Assessment of the intracellular glucocorticoid receptor (GCR) level may be useful in monitoring functional disturbances of the hypothalamic-pituitary-adrenocortical axis or effects of prolonged steroid therapy. Cytosolic ligand binding assays have recently been supplemented by flow cytometric determination of receptor expression in individual cells. A method based on multiparametric analysis of whole blood by simultaneous labelling of intracellular GCRs and surface markers of lymphocyte subsets is described. We examined 25 healthy male volunteers and 35 age- and sex-matched post-traumatic stress disorder (PTSD) patients within 8 years from traumatic event. PTSD patients had a lower relative quantity of GCR in all lymphocyte populations tested as compared with healthy volunteers. NK cells of both groups showed higher expression of GCR than other lymphocyte subsets. In PTSD patients, the expression of GCR in B lymphocytes was also higher than in T cell. Although serum cortisol level was lower in PTSD patients, there was no correlation between cortisol level and GCR expression. Multiparameter flow cytometric determination of GCR expression in lymphocyte subpopulations may provide a useful tool for monitoring immunoregulatory action of glucocorticoids.