Psychoneuroendocrinology of depression. Hypothalamic-pituitary-adrenal axis

Herbal medicine for depression, anxiety and insomnia: a review of psychopharmacology and clinical evidence

Research in the area of herbal psychopharmacology has increased markedly over the past decades. To date however, a comprehensive review of herbal antidepressant, anxiolytic and hypnotic psychopharmacology and applications in depression, anxiety and insomnia has been absent. A search of MEDLINE (PubMed), CINAHL, PsycINFO, and the Cochrane Library databases was conducted (up to February 21st 2011) on commonly used psychotropic herbal medicines. A review of the literature was conducted to ascertain mechanisms of action of these botanicals, in addition to a systematic review of controlled clinical trials for treatment of mood, anxiety and sleep disorders, which are common comorbid psychiatric disorders. Specific emphasis was given to emerging phytomedicines. Analysis of evidence levels was conducted, as were effect sizes (Cohen's d) where data were available. Results provided evidence of a range of neurochemical, endocrinological, and epigenetic effects for 21 individual phytomedicines, which are detailed in this paper. Sixty six controlled studies were located involving eleven phytomedicines. Several of these provide a high level of evidence, such as Hypericum perforatum for major depression, and Piper methysticum for anxiety disorders. Several human clinical trials provide preliminary positive evidence of antidepressant effects (Echium amoenum, Crocus sativus, and Rhodiola rosea) and anxiolytic activity (Matricaria recutita, Ginkgo biloba, Passiflora incanata, E. amoenum, and Scutellaria lateriflora). Caution should however be taken when interpreting the results as many studies have not been replicated. Several herbal medicines with in vitro and in vivo evidence are currently unexplored in human studies, and along with use of emerging genetic technologies "herbomics", are areas of potential future research.

Elevated macrophage migration inhibitory factor and decreased transforming growth factor-beta levels in major depression--no influence of celecoxib treatment

OBJECTIVES

The involvement of an immune process in the pathophysiology of major depression disorder (MDD) was substantiated by studies demonstrating elevated levels of proinflammatory cytokines and prostaglandin E(2) (PGE(2)). Cyclooxygenase-2 (COX-2) inhibitors lead to a reduced production of PGE(2) and have been shown to improve depressive symptoms. We investigated the three immune parameters macrophage migration inhibitory factor (MIF), transforming growth factor-β (TGF-β) and soluble CD14 (sCD14) in a randomized, placebo-controlled trial of the COX-2 inhibitor celecoxib as add-on therapy in patients with MDD treated with reboxetine.

METHODS

Thirty-two patients with depression and 20 healthy controls participated in the study. The patients were treated with reboxetine and celecoxib or placebo. Immune parameters were measured from serum at baseline, after three and five weeks using ELISA.

RESULTS

Celecoxib as add-on strategy resulted in a significant reduction of Hamilton Depression Scale scores compared to placebo. Depressed patients showed significantly elevated MIF (p < 0.001) and reduced TGF-β (p = 0.006) concentrations at baseline. There was no difference in sCD14-concentrations. There was no difference between the placebo and the celecoxib group and no change over time.

LIMITATIONS

Limitations of the study are the relatively small sample size and lack of functional assessment of HPA axis in parallel.

CONCLUSIONS

MIF is a promising new candidate in the neuro-immune interplay that may link depressive symptoms, altered immune state and HPA-axis dysregulation. Reduced levels of TGF-β replicate previous findings and support the importance of this regulatory cytokine in major depressive disorder.

Association between social isolation and inflammatory markers in depressed and non-depressed individuals: results from the MONICA/KORA study

INTRODUCTION

Depressed individuals not only suffer from chronic low grade inflammation, but also exhibit an inflammatory hyper-responsiveness to acute stress. We investigate whether chronic stress also induces an exaggerated inflammatory response in individuals with increased depression features. As model for chronic stress, social isolation was chosen.

METHODS

Interleukin (IL)-6 and hs-CRP levels were assessed in 1547 subjects (847 men and 700 women), derived from the population-based MONICA/KORA study. Standardized questionnaires were used to assess depressed mood (depression and exhaustion subscale) and social isolation (social network index). The relationship between the two inflammatory markers, social isolation and depressed mood was examined taking into account interactions social isolation × depressed mood using multivariable linear regression models, adjusted for age, BMI, smoking, alcohol, and physical activity. Analyses were performed in men and women separately.

RESULTS

We observed a significant interaction between depressed mood and social isolation regarding IL-6 and hs-CRP, respectively in men (p-value=0.02 for IL-6 and <0.01 for hs-CRP), evidencing a substantial synergistic effect of social isolation, and depressed mood on inflammatory responses. Furthermore, depressed and socially isolated men had highly significantly elevated IL-6 levels (geometric mean: 3.76 vs. 1.92 pg/ml, p-value <0.01) and heightened hs-CRP levels (geometric mean: 2.01 vs. 1.39 mg/l, p=0.08) in comparison with non-depressed and socially integrated men. In women, no significant associations were seen.

CONCLUSION

The interaction of depressed mood and social isolation elicits a substantial synergistic impact on inflammatory markers in men, but not in depressed women.

Suicidality and epilepsy: a neuropsychobiological perspective

People with epilepsy (PWE) are at increased risk of experiencing suicidal ideation, displaying suicidal behavior, and committing suicide than the general population. The relationship between suicidality and epilepsy is complex and multifactorial in which operant pathogenic mechanisms include epilepsy-related variables, personal and familial psychiatric history, and iatrogenic effects. Furthermore, a bidirectional relationship between suicidality and epilepsy has suggested the existence of common neurobiological pathogenic mechanisms operant in both conditions and including disturbances of several neurotransmitters, in particular, serotonin (5HT), norepinephrine (NE), glutamate (GTE), and γ-aminobutyric acid (GABA), and disturbances of the hypothalamic-pituitary-adrenal axis (HPAA), which, in turn, can result in abnormal secretion of some of these neurotransmitters. The purpose of this article is to review these common neurobiological pathogenic mechanisms.

Serotonin, depression, and cardiovascular disease: sex-specific issues

The comorbidity of cardiovascular disease (CVD) and depression/anxiety disorders is well established, but the mechanisms are not well understood. This paper will review the epidemiological and biological evidence for the role of depression in CVD, as well as the pathophysiological process underlying both depression and CVD. The focus will be on the roles of serotonin, platelets, and the immune system, with an emphasis on the relevance of sex differences in both depression/anxiety and CVD as they pertain to women.

Chronic deep brain stimulation of the lateral habenula nucleus in a rat model of depression

In the present study, we aim to determine the antidepressant effects of chronic deep brain stimulation (DBS) of the lateral habenula nucleus (LHb) in a rat model of depression and to explore the potential mechanism of DBS induced improvement of depressive symptoms. To establish the rat depression model, animals were repeatedly exposed to a set of chronic mild stressors for four consecutive weeks. The open-field and sucrose consumption tests were used as measures of depression. For DBS treatment, rats were stereotaxically implanted with electrodes into the LHb and stimulated over a course of 28 d. A separate positive control group was given pharmacotherapy with clomipramine hydrochloride. Open-field testing was used to determine behavioral changes following DBS treatment. Monoamine concentrations in blood and brain tissues were determined by fluorescence spectrophotometry. This study demonstrates that DBS of the LHb region significantly improved depressive-like symptoms in the rat model. These improvements manifested as elevated numbers of crossings and rearings during the open-field test in DBS-treated depressed rats compared to controls. In addition, concentrations of monoamines including norepinephrine (NE), dopamine (DA), and serotonin (5-HT) in blood serum and brain tissues were also increased by DBS of the LHb. Therefore, significant improvements in all outcomes were detected following chronic DBS treatment. These results indicate that long-term DBS treatment of the LHb region effectively improved depressive symptoms in rats, likely as a result of elevated monoamine levels. LHb DBS may therefore provide a valuable therapeutic strategy for the clinical treatment of depression.

The liver-cytokine-brain circuit in interferon-based treatment of patients with chronic viral hepatitis

Psychiatric symptoms are commonly identified in patients with viral hepatitis. They may have been present prior to the onset of disease and may include symptoms related to addiction issues. Furthermore, the virus and antiviral therapy, in particular interferon, may induce or modify psychiatric symptoms. Recent data support chronic hepatitis C replication in the brain and subsequent changes of cerebral metabolite spectra and magnetic resonance alterations. In chronic viral hepatitis and in other chronic inflammatory diseases, an alteration of the neuro-endocrine-immune system response has been observed. Catecholamines and glucocorticoids modulate this immune/inflammatory reaction. Psychiatric assessment and monitoring before, during and after antiviral therapy can identify patients whose psychiatric symptoms preclude therapy, and those who may benefit from psychopharmacological therapy and counselling, thereby improving therapeutic results. This review will discuss current insights into the complex interplay between cytokines, liver and brain in chronic viral hepatitis closely associated with psychiatric issues, especially in the case of antiviral therapy, with the aim of indicating future research and possible treatments.

Self-assessed parental depressive problems are associated with blunted cortisol responses to a social stress test in daughters. The TRAILS Study

Depression runs in families and is considered a stress-related disorder. Familial risk for depression may be transmitted via deregulated psychophysiological stress responses from parent to child. In this study, we examined the association between self-assessed lifetime parental depressive problems (PDP) and adolescent offspring' cortisol responses to a social stress test. Data were collected as part of the third assessment wave of TRAILS (TRacking Adolescents' Individual Lives Survey), a large prospective population study of Dutch adolescents. Data of 330 adolescents (mean age 16.04; 40.9% girls) who participated in a laboratory session, including a standardized performance-related social stress task (public speaking and mental arithmetic) were examined. Four saliva cortisol samples were collected before, during and after the social stress task which were analyzed with repeated measures Analysis of Variance. Lifetime parental depressive problems were assessed by self-reports from both biological parents. PDP was associated with daughter' cortisol responses (F(3,133)=3.90, p=.02), but no association was found in sons (F(3,193)=0.27, p=.78). Girls whose parents ever experienced depressive symptoms displayed a blunted cortisol response to the standardized social stress test, while girls whose parents never had such problems displayed the characteristic curvilinear response pattern. This effect was not mediated by offspring stress history (age 0-16). Analyses were corrected for smoking behaviour and adolescent depressed mood. The fact that PDP were measured by self-report questionnaires and did not reflect clinical DSM-IV diagnosis could be considered a limitation of the study.

The WAG/Rij strain: a genetic animal model of absence epilepsy with comorbidity of depression [corrected]

A great number of clinical observations show a relationship between epilepsy and depression. Idiopathic generalized epilepsy, including absence epilepsy, has a genetic basis. The review provides evidence that WAG/Rij rats can be regarded as a valid genetic animal model of absence epilepsy with comorbidity of depression. WAG/Rij rats, originally developed as an animal model of human absence epilepsy, share many EEG and behavioral characteristics resembling absence epilepsy in humans, including the similarity of action of various antiepileptic drugs. Behavioral studies indicate that WAG/Rij rats exhibit depression-like symptoms: decreased investigative activity in the open field test, increased immobility in the forced swimming test, and decreased sucrose consumption and preference (anhedonia). In addition, WAG/Rij rats adopt passive strategies in stressful situations, express some cognitive disturbances (reduced long-term memory), helplessness, and submissiveness, inability to make choice and overcome obstacles, which are typical for depressed patients. Elevated anxiety is not a characteristic (specific) feature of WAG/Rij rats; it is a characteristic for only a sub-strain of WAG/Rij rats susceptible to audiogenic seizures. Interestingly, WAG/Rij rats display a hyper-response to amphetamine similar to anhedonic depressed patients. WAG/Rij rats are sensitive only to chronic, but not acute, antidepressant treatments, suggesting that WAG/Rij rats fulfill a criterion of predictive validity for a putative animal model of depression. However, more and different antidepressant drugs still await evaluation. Depression-like behavioral symptoms in WAG/Rij rats are evident at baseline conditions, not exclusively after stress. Experiments with foot-shock stress do not point towards higher stress sensitivity at both behavioral and hormonal levels. However, freezing behavior (coping deficits) and blunted response of 5HT in the frontal cortex to uncontrollable sound stress, increased c-fos expression in the terminal regions of the meso-cortico-limbic brain systems and greater DA response of the mesolimbic system to forced swim stress suggest that WAG/Rij rats are vulnerable to some, but not to all types of stressors. We propose that genetic absence epileptic WAG/Rij rats have behavioral depression-like symptoms, are vulnerable to stress and might represent a model of chronic low-grade depression (dysthymia). Both 5HT and DAergic abnormalities detected in the brain of WAG/Rij rats are involved in modulation of vulnerability to stress and provocation of behavioral depression-like symptoms. The same neurotransmitter systems modulate SWDs as well. Recent studies suggest that the occurrence and repetition of absence seizures are a precipitant of depression-like behavior. Whether the neurochemical changes are primary to depression-like behavioral alterations remains to be determined. In conclusion, the WAG/Rij rats can be considered as a genetic animal model for absence epilepsy with comorbidity of dysthymia. This model can be used to investigate etiology, pathogenic mechanisms and treatment of a psychiatric comorbidity, such as depression in absence epilepsy, to reveal putative genes contributing to comorbid depressive disorder, and to screen novel psychotropic drugs with a selective and/or complex (dual) action on both pathologies.

[Clinical aspects of the link between diabetes and depression]

Diabetes mellitus and depression are public health concerns of the present and, as predicted, also the future. The observation that depression is seen more frequently in diabetic patients compared to the non-diabetic population has been proven by several recent studies. The co-occurrence carries further risks for the affected patients, as depression in diabetics may affect sufficient treatment of diabetes and enhance the development of diabetic complications. These may further worsen depressive symptoms causing a vicious cycle in these patients. In the present paper authors discuss in detail the theoretic and practical issues of the complex two directional relationships between diabetes and depression. Their goal is to draw attention to depression as co-morbidity of diabetes that may interfere with the optimization of diabetic patient's carbohydrate metabolism. If sufficient glycaemic control is not achieved using routine clinical methods depression should be evaluated as a probable cause. If needed, depression should be treated to improve the medical outcomes and quality of life of diabetic patients.

Hydrocortisone impairs working memory in healthy humans, but not in patients with major depressive disorder

OBJECTIVE

Several studies have shown that stress or the administration of glucocorticoids can impair hippocampus-based declarative memory retrieval and prefrontal dependent working memory performance in healthy subjects. Major Depressive Disorder (MDD) is often characterized by memory impairment and increased cortisol secretion. Studies indicate that the impairing effects of glucocorticoids on declarative memory performance are missing in patients with MDD. The purpose of our study was to investigate whether the finding of missing effects of acute cortisol administration on memory performance in MDD is also seen when examining prefrontal-based working memory.

METHODS

In a placebo-controlled study, 57 patients with MDD and 56 sex- and age-matched healthy control subjects received either placebo or 10 mg of hydrocortisone orally before memory testing. To test the verbal modality of working memory, the Word Suppression Test was applied with one negative and one neutral test part.

RESULTS

After hydrocortisone intake, healthy subjects showed a significantly poorer working memory performance compared to placebo treatment when negative interference words were administered. In contrast, memory performance of MDD patients was not affected by hydrocortisone treatment.

CONCLUSIONS

The missing effects of glucocorticoid administration on working memory in MDD might be interpreted in the context of reduced central glucocorticoid receptor function.

Plasticity of presynaptic and postsynaptic serotonin 1A receptors in an animal model of epilepsy-associated depression

Depression is a common comorbidity of temporal lobe epilepsy and has highly negative impact on patients' quality of life. We previously established that pilocarpine-induced status epilepticus (SE) in rats, concurrently with chronic epilepsy leads to depressive impairments, and that the latter may stem from the dysregulation of hypothalamo-pituitary-adrenocortical (HPA) axis and/or diminished raphe-hippocampal serotonergic transmission. We examined possible involvement of presynaptic and postsynaptic serotonin 1A (5-HT1A) receptors in epilepsy-associated depression. Based on their performance in the forced swim test (FST), post-SE animals were classified as those with moderate and severe depressive impairments. In moderately impaired rats, the activity of the HPA axis (examined using plasma corticosterone radioimmunoassay) was higher than in naive subjects, but the functional capacity of presynaptic 5-HT1A receptors (measured in raphe using autoradiography) remained unaltered. In severely depressed animals, both the activity of the HPA axis and the function of presynaptic 5-HT1A receptors were increased as compared with naive and moderately depressed rats. Pharmacological uncoupling of the HPA axis from raphe nucleus exerted antidepressant effects in severely impaired rats, but did not modify behavior in both naive and moderately depressed animals. Further, the function of postsynaptic 5-HT1A receptors was diminished in the hippocampus of post-SE rats. Pharmacological activation of postsynaptic 5-HT1A receptors improved depressive deficits in epileptic animals. We suggest that under the conditions of chronic epilepsy, excessively hyperactive HPA axis activates presynaptic 5-HT1A receptors, thus shifting the regulation of serotonin release in favor of autoinhibition. Downregulation of postsynaptic 5-HT1A receptors may further exacerbate the severity of epilepsy-associated depression.

Four potential criteria for deciding when to use antidepressants or psychotherapy for unipolar depression: a literature review

OBJECTIVE

To evaluate the literature supporting four potential criteria for deciding whether to use psychotherapy or pharmacology when treating depression.

METHOD

Literature review of the evidence from the last 10 years on presenting patient's demographics, aetiology, comorbidity, and genetic factors, as predictors of treatment outcome efficacy.

RESULTS

Demographic information has little support as a potential criteria for decision-making; aetiology (melancholic vs. non-melancholic) has significant support; presence of personality disorder comorbidity is unproven as a criterion but may have some value; genetic predisposition has the strongest evidence supporting it as a criteria for treatment decision-making.

CONCLUSION

Although some presenting cases will be easier to classify than others, there are substantial data supporting the screening of patients according to three of these criteria.

Plasma omega 3 polyunsaturated fatty acid status and monounsaturated fatty acids are altered by chronic social stress and predict endocrine responses to acute stress in titi monkeys

Disturbances in fatty acid (FA) metabolism may link chronic psychological stress, endocrine responsiveness, and psychopathology. Therefore, lipid metabolome-wide responses and their relationships with endocrine (cortisol, insulin, and adiponectin) responsiveness to acute stress (AS) were assessed in a primate model of chronic social stress (CS). Compared to controls (not exposed to CS), CS increased (P≤0.05) circulating triacylglycerol (TG) and phosphatidylethanolamine (PE) n-6/n-3 and reduced (P≤0.05) cholesterol ester (CE) 16:1n7 and phosphatidylcholine (PC) 18:1n7, suggesting lower omega-3 FA status and stearoyl-CoA desaturase activity, respectively. Cortisol responses to AS positively correlated with TG n-6/n-3 (r=0.93; P=0.007), but only in CS monkeys. The adiponectin response to AS inversely correlated with CE n-6/n3 (r=-0.89; P=0.045) and positively with TG 16:1n7 (r=0.98; P=0.004), only in CS monkeys. Our results are consistent with previously reported FA profiles in stress-related psychopathology and suggest that compositional changes of specific lipid FAs may form new functional markers of chronic psychological stress.

Are behavioral effects of early experience mediated by oxytocin?

Early experiences can alter adaptive emotional responses necessary for social behavior as well as physiological reactivity in the face of challenge. In the highly social prairie vole (Microtus ochrogaster), manipulations in early life or hormonal treatments specifically targeted at the neuropeptides oxytocin (OT) and arginine vasopressin (AVP), have long-lasting, often sexually dimorphic, consequences for social behavior. Here we examine the hypothesis that behavioral changes associated with differential early experience, in this case handling the family during the first week of life, may be mediated by changes in OT or AVP or their brain receptors. Four early treatment groups were used, differing only in the amount of manipulation received during the first week of life. MAN1 animals were handled once on post-natal day 1; MAN1 treatment produces a pattern of behavior usually considered typical of this species, against which other groups were compared. MAN1-7 animals were handled once a day for post-natal days 1-7, MAN 7 animals were handled once on post-natal day 7, and MAN0 animals received no handling during the first week of life. When tested following weaning, males in groups that had received manipulation during the first few days of life (MAN1 and MAN1-7) displayed higher alloparenting than other groups. Neuroendocrine measures, including OT receptor binding and OT and AVP immunoreactivity, varied by early treatment. In brain areas including the nucleus accumbens, bed nucleus of stria terminalis and lateral septum, MAN0 females showed increased OT receptor binding. MAN1 animals also displayed higher numbers of immunoreactive OT cell bodies in the supraoptic nucleus. Taken together these findings support the broader hypothesis that experiences in the first few days of life, mediated in part by sexually dimorphic changes in neuropeptides, especially in the receptor for OT, may have adaptive consequences for sociality and emotion regulation.

Do stress hormones connect environmental effects with behavior in the forced swim test?

Forced swim test (FST) is a widely used test for antidepressant development. Depression is a stress related disease, as hormones of the stress-axis can modify mood. However it is not clear, how the appearance of depressive-like behavior (floating) in FST is connected with changes in the stress-hormone levels. We hypothesized, that different manipulations would alter the behavior through changes in stress-hormone levels. First the effect of environmental alterations was studied. Increasing water-temperature enhanced floating time together with a decrease in adrenocorticotropin levels. During the dark phase of the day rats spent more time with floating independently from the actual lighting. Neither the phase nor the actual lighting had significant effect on adrenocorticotropin concentrations with higher corticosterone levels during the dark phase. At greater water depth rats float less but the size of animals had no effect. Water depth did not influence adrenocorticotropin and corticosterone responses, but the size of the rats significantly affected both factors. Secondly, administration of imipramine reduced floating and adrenocorticotropin level without affecting corticosterone. Despite the known connection between depression and stress we did not find a correlation between floating behavior and hormone levels. As an alternative mechanism imipramine-induced heart rate and core body temperature decrease was found by telemetric approach. This study is the first summary in rats examining the effect of wide range of environmental alterations during FST. It seems likely that both brain monoamines and stress-axis take part in the development of depression, but these pathways are regulated independently.

The hypothalamic-pituitary-adrenal axis and serotonin abnormalities: a selective overview for the implications of suicide prevention

Suicidal behavior and mood disorders are one of the world's largest public health problems. The biological vulnerability for these problems includes genetic factors involved in the regulation of the serotonergic system and stress system. The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates the body's response to stress and has complex interactions with brain serotonergic, noradrenergic and dopaminergic systems. Corticotropin-releasing hormone and vasopressin act synergistically to stimulate the secretion of ACTH that stimulates the biosynthesis of corticosteroids such as cortisol from cholesterol. Cortisol is a major stress hormone and has effects on many tissues, including on mineralocorticoid receptors and glucocorticoid receptors in the brain. Glucocorticoids produce behavioral changes, and one important target of glucocorticoids is the hypothalamus, which is a major controlling center of the HPA axis. Stress plays a major role in the various pathophysiological processes associated with mood disorders and suicidal behavior. Serotonergic dysfunction is a well-established substrate for mood disorders and suicidal behavior. Corticosteroids may play an important role in the relationship between stress, mood changes and perhaps suicidal behavior by interacting with 5-HT1A receptors. Abnormalities in the HPA axis in response to increased levels of stress are found to be associated with a dysregulation in the serotonergic system, both in subjects with mood disorders and those who engage in suicidal behavior. HPA over-activity may be a good predictor of mood disorders and perhaps suicidal behavior via abnormalities in the serotonergic system.

SRD5A2 is associated with increased cortisol metabolism in schizophrenia spectrum disorders

OBJECTIVE

Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is documented in bipolar disorder and schizophrenia, but the mechanism is unclear; recently, increased activity of cortisol metabolizing enzymes was indicated in these disorders. We investigated whether five genes involved in cortisol metabolism were associated with altered activity of cortisol metabolizing enzymes in bipolar disorder (BD) and schizophrenia spectrum disorders (SCZ).

METHODS

A case-control sample of subjects with BD (N=213), SCZ (N=274) and healthy controls (N=370) from Oslo, Norway, were included and genotyped from 2003 to 2008. A sub-sample (healthy controls: N=151; SCZ: N=40; BD: N=39) had estimated enzyme activities based on measurements of urinary free cortisol, urinary free cortisone and metabolites. A total of 102 single nucleotide polymorphisms (SNPs) in the SRD5A1, SRD5A2, AKR1D1, HSD11B1 and HSD11B2 genes were genotyped, and significant SNPs analyzed in the sub-sample.

RESULTS

There was a significant association of rs6732223 in SRD5A2 (5α-reductase) with SCZ (p=0.0043, Bonferroni corrected p=0.030, T risk allele). There was a significantly increased 5α-reductase activity associated with rs6732223 (T allele) within the SCZ group (p=0.011).

CONCLUSIONS

The present data suggest an interaction between SCZ and SRD5A2 variants coding for the enzyme 5α-reductase, giving rise to increased 5α-reductase activity in SCZ. The findings may have implications for cortisol metabolizing enzymes as possible drug targets.

Prevalence of depression in relation to glucose intolerance in urban south Indians--the Chennai Urban Rural Epidemiology Study (CURES-76)

BACKGROUND

This study investigated the association between depression and glucose intolerance in urban residents of southern India.

METHODS

Subjects were recruited from the Chennai Urban Rural Epidemiology Study, carried out on a representative sample of 26,001 subjects recruited from Chennai city in southern India. Subjects with known diabetes were excluded (n = 1,498). Of the remaining 24,503 subjects, fasting capillary blood glucose (FBG) estimation were available for 23,787 subjects (response rate, 97.1%) in whom depression was assessed using a validated instrument, the Patient Health Questionnaire-12. Subjects with FBG values ≥126 mg/dL were termed as subjects with newly diagnosed diabetes (NDD), those with values between 100 and 125 mg/dL as having impaired fasting glucose (IFG), and those with <100 mg/dL as having normal fasting glucose (NFG).

RESULTS

The overall prevalence of depression was 14.3% (3391 of 23,787 subjects), and an increasing prevalence of depression was seen with increasing grades of glucose intolerance: NFG (13.1%), IFG (15.7%), and NDD (19.7%) (trend χ(2) = 57.1, P < 0.001). The prevalence of depression was higher in females at all grades of glucose intolerance. Risk for depression was higher among NDD subjects compared to NFG subjects (odds ratio = 1.12, 95% confidence interval 1.03-1.22, P = 0.01) and IFG subjects (odds ratio 1.21, 95% confidence interval 1.02-1.44, P = 0.03) and also for IFG compared to NFG subjects (odds ratio = 1.12, 95% confidence interval 1.02-1.21, P = 0.01) after adjusting for age, gender, body mass index, hypertension, and socioeconomic status.

CONCLUSION

The prevalence of depression increases with increasing grades of glucose intolerance and is highest among those with diabetes.

Association of depressive symptoms and social support on blood pressure among urban African American women and girls

PURPOSE

The purpose of this study was to explore the associations between depressive symptoms and perceived social support on blood pressure in African American women.

DATA SOURCES

This cross-sectional study was conducted among 159 African American women from multiple sites in the Detroit Metro area.

CONCLUSIONS

Results from this study found that both higher systolic and diastolic blood pressure were positively associated with higher depressive symptom scores (r= .20 and .18, p < .05). Higher depressive symptoms scores were, in turn, significantly associated with lower social support scores (r=-.44, p < .001). However, total social support scores were not significantly correlated with blood pressure readings. Higher depressive symptom scores were associated with increased systolic blood pressure independent of social support.

IMPLICATIONS FOR PRACTICE

Findings of the present study suggest the importance of appropriate social support to help alleviate depressive symptoms. However, to effectively control blood pressure in patients with depressive symptoms, other pathophysiologic mechanisms between depressive symptoms and elevated blood pressures independent of social support should be examined in future research. Future studies should consider a cohort design to examine the temporal relationship of depressive symptoms, social support, and blood pressure readings.

Upward spirals of positive emotions counter downward spirals of negativity: insights from the broaden-and-build theory and affective neuroscience on the treatment of emotion dysfunctions and deficits in psychopathology

This review integrates Fredrickson's broaden-and-build theory of positive emotions with advances in affective neuroscience regarding plasticity in the neural circuitry of emotions to inform the treatment of emotion deficits within psychopathology. We first present a body of research showing that positive emotions broaden cognition and behavioral repertoires, and in so doing, build durable biopsychosocial resources that support coping and flourishing mental health. Next, by explicating the processes through which momentary experiences of emotions may accrue into self-perpetuating emotional systems, the current review proposes an underlying architecture of state-trait interactions that engenders lasting affective dispositions. This theoretical framework is then used to elucidate the cognitive-emotional mechanisms underpinning three disorders of affect regulation: depression, anxiety, and schizophrenia. In turn, two mind training interventions, mindfulness and loving-kindness meditation, are highlighted as means of generating positive emotions that may counter the negative affective processes implicated in these disorders. We conclude with the proposition that positive emotions may exert a countervailing force on the dysphoric, fearful, or anhedonic states characteristic of psychopathologies typified by emotional dysfunctions.

Sensitivity to the depressogenic effect of stress and HPA-axis reactivity in adolescence: a review of gender differences

Adolescence is characterized by major biological, psychological, and social challenges, as well as by an increase in depression rates. This review focuses on the association between stressful experiences and depression in adolescence, and the possible role of the hypothalamus-pituitary-adrenal cortex (HPA-)axis in this link. Adolescent girls have a higher probability to develop depressive symptoms than adolescent boys and preadolescents. Increasing evidence indicates that girls' higher risk of depression is partly brought about by an increased sensitivity for stressful life events, particularly interpersonal stressors, which are highly prevalent in adolescent girls. Genetic risk factors for depression, as well as those for stress sensitivity, are often expressed differently in girls and boys. Also environmental adversity tends to affect girls' stress responses more than those of boys. These gender-specific association patterns have been reported for both sensitivity to stressful life events and HPA-axis responses to social stress. Together, the findings suggest that girls are more malleable than boys in response to internal and external influences. This postulated greater malleability may be adaptive in many circumstances, but also brings along risk, such as an increased probability of depression.

N-3 (omega-3) Fatty acids in postpartum depression: implications for prevention and treatment

A growing body of clinical and epidemiological evidence suggests that low dietary intake and/or tissue levels of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) are associated with postpartum depression. Low tissue levels of n-3 PUFAs, particularly docosahexaenoic acid (DHA), are reported in patients with either postpartum or nonpuerperal depression. Moreover, the physiological demands of pregnancy and lactation put childbearing women at particular risk of experiencing a loss of DHA from tissues including the brain, especially in individuals with inadequate dietary n-3 PUFA intake or suboptimal metabolic capabilities. Animal studies indicate that decreased brain DHA in postpartum females leads to several depression-associated neurobiological changes including decreased hippocampal brain-derived neurotrophic factor and augmented hypothalamic-pituitary-adrenal responses to stress. Taken together, these findings support a role for decreased brain n-3 PUFAs in the multifactorial etiology of depression, particularly postpartum depression. These findings, and their implications for research and clinical practice, are discussed.

Maternal laboratory stress influences fetal neurobehavior: cortisol does not provide all answers

OBJECTIVE

Maternal stress can have an impact on pregnancy. However, effects on fetal neurobehavior are not well understood. In this study, the effect of laboratory stress on maternal psychoneuroendocrinological response and on fetal neurobehavior was studied. Serum cortisol as a potential underlying mechanism was measured.

METHODS

Twenty-seven women made a single 1.5-h visit in their third trimester. The laboratory stressor involved an arithmetic task. Associations between maternal laboratory stress response and fetal neurobehavior were analyzed by studying 19 maternal-fetal dyads with high signal quality cardiotocograms.

RESULTS

Stress exposure changed participants stress perception (p < 0.0001). However, only half of the participants (responders) had an HPA-axis response. Fetuses responded to the stress exposure depending on their mothers' stress response: (i) there was a fetal heart rate (FHR) group effect at the level of trend (p = 0.06). Fetuses of responders had higher HR levels 20 min after the exposure (p = 0.043), (ii) there were interaction (p = 0.026) and group effects at the level of trend (p = 0.078) found for FHR short-term variation (STV). Fetuses of responders had lower FHR STV 20 min after stress exposure (p = 0.007). Cortisol as a potential underlying mechanism only seemed to be associated with short- and long-term variation of FHR.

CONCLUSIONS

An activation of the maternal stress-system could result in a child being born having a history of responding to maternal stress.

Eating ourselves to death (and despair): the contribution of adiposity and inflammation to depression

Obesity and related metabolic conditions are of epidemic proportions in most of the world, affecting both adults and children. The accumulation of lipids in the body in the form of white adipose tissue in the abdomen is now known to activate innate immune mechanisms. Lipid accumulation causes adipocytes to directly secrete the cytokines interleukin (IL) 6 and tumor necrosis factor alpha (TNFalpha), but also monocyte chemoattractant protein 1 (MCP-1), which results in the accumulation of leukocytes in fat tissue. This sets up a chronic inflammatory state which is known to mediate the association between obesity and conditions such as cardiovascular disease, type 2 diabetes, and cancer. There is also a substantial literature linking inflammation with risk for depression. This includes the observations that: (1) people with inflammatory diseases such as multiple sclerosis, cardiovascular disease, and psoriasis have elevated rates of depression; (2) many people administered inflammatory cytokines such as interferon alpha develop depression that is indistinguishable from depression in non-medically ill populations; (3) a significant proportion of depressed persons show upregulation of inflammatory factors such as IL-6, C-reactive protein, and TNFalpha; (4) inflammatory cytokines can interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. While many factors may contribute to the association between inflammatory mediators and depression, we hypothesize that increased adiposity may be one causal pathway. Mediational analysis suggests a bi-directional association between adiposity and depression, with inflammation possibly playing an intermediary role.

A subchronic application period of glucocorticoids leads to rat cognitive dysfunction whereas physostigmine induces a mild neuroprotection

The cholinergic neurotransmitter system and prolonged glucocorticoid-induced stress can affect cognitive functions in opposite ways. While pharmacological enhancement of cholinergic neurotransmission is known to induce neuroprotective effects, chronic glucocorticoids impair cognitive functions. Up to now, there is no consensus as to whether a subchronic stress period of several days would affect cognitive function. The goal of this study was to investigate whether or not repeated applications of physostigmine over 3 days lead to protective effects on rat spatial cognitive abilities in contrast to the deteriorating effect on rat cognitive function after corticosterone treatment. Furthermore, we wanted to investigate in what extent this cognition-modulating effect is associated with rat cerebral acetylcholinergic system. Male adult rats (n = 40) were randomly divided into four groups with n = 10 per group: (I) placebo-, (II) corticosterone- (15 mg/day), (III) physostigmine- (0.014 mg/day), and (IV) physostigmine + corticosterone-treated rats. Body mass and plasma corticosterone concentrations were measured. Psychometric investigations were conducted using a Morris water maze before and after a subchronic treatment. In cerebral tissue, ACh and acetylcholinesterase (AChE) content and ACh receptor density were determined. Tissue corticosterone concentration was measured in cerebral cortex, hippocampus, and adrenal glands. In corticosterone-treated rats, reduced spatial cognitive abilities were associated with a significant increase in plasma (+25%) and cerebral corticosterone levels (+350%) parallelled by a significant reduction in adrenal gland concentrations (-84%) as compared to placebo. Repeated physostigmine injections improved rats' spatial memory and increased cerebral ACh and AChE content (p < 0.05). When physostigmine was administered at the same time as corticosterone (group IV), it was not able to reverse the corticosterone effect. A significant correlation was detected between cerebral AChE and corticosterone concentrations as well as between AChE and psychometric parameters. We conclude that subchronic exogenous corticosterone administration induces memory dysfunction whereas physostigmine exerts cognitive-enhancing effects if given for 3 days. An apparently existing interaction between glucocorticoid excess and ACh metabolism is discussed.

The BDNF Val66Met polymorphism affects HPA-axis reactivity to acute stress

BACKGROUND

Growing evidence suggests that individual differences in HPA-axis reactivity to psychosocial stress are partly due to heritable influences. However, knowledge about the role of specific genetic variants remains very limited to date. Since brain-derived neurotrophic factor (BDNF) not only exhibits neurotrophic actions but is also involved in the regulation of hypothalamic neuropeptides, we investigated the role of a common functional polymorphism within the BDNF gene (BDNF Val66Met) in the context of endocrine and cardiovascular stress reactivity.

METHODS

Healthy male adults (N=100) were genotyped and exposed to a standardized laboratory stress task (Public Speaking). Saliva cortisol and self-reported mood levels were obtained at 6 time points prior to the stressor and during an extended recovery period. Furthermore, heart rate reactivity as an indicator of sympathetic activation was monitored continuously during the experimental procedure.

RESULTS

We report a small, but significant effect of the BDNF Val66Met polymorphism on stress reactivity. More precisely, carriers of the met-allele showed a significantly attenuated HPA-axis and cardiovascular reactivity to the psychosocial stressor compared to subjects with the val/val genotype. Furthermore, the diminished physiological response in met-allele carriers was also attended by significantly lower self-reported ratings of perceived stress and nervousness.

CONCLUSION

Our findings of a diminished endocrine and cardiovascular stress response in healthy male adults is consistent with a previously published study and adds further evidence for a crucial role of the BDNF Val66Met polymorphism in the modulation of stress reactivity.

Lessons learned from herbal medicinal products: the example of St. John's Wort (perpendicular)

The example of St. John's wort offers convincing evidence for the concept that modern methods of pharmacological and phytochemical research are effective in advancing the development of traditional herbal remedies. As a consequence of these efforts, it is known today that several compounds from different structural groups and with different mechanisms of action seem to be responsible for the observed antidepressant efficacy of St. John's Wort. Co-effectors in the extract improve the bioavailability of active constituents such as hypericin (1) (pharmacokinetic synergy). Unwanted side effects are preventable without remarkable loss of activity when the responsible constituent(s) are carefully removed during the extraction process, as demonstrated for hyperforin (3), which is responsible for the induction of cytochrome P450 (CYP)-metabolizing enzymes (CYP3A4, in particular). On the basis of our findings, it is likely that positive interactions between single compounds occur more frequently in traditionally used herbal preparations than is known presently.

Aggression and anxiety: social context and neurobiological links

Psychopathologies such as anxiety- and depression-related disorders are often characterized by impaired social behaviours including excessive aggression and violence. Excessive aggression and violence likely develop as a consequence of generally disturbed emotional regulation, such as abnormally high or low levels of anxiety. This suggests an overlap between brain circuitries and neurochemical systems regulating aggression and anxiety. In this review, we will discuss different forms of male aggression, rodent models of excessive aggression, and neurobiological mechanisms underlying male aggression in the context of anxiety. We will summarize our attempts to establish an animal model of high and abnormal aggression using rats selected for high (HAB) vs. low (LAB) anxiety-related behaviour. Briefly, male LAB rats and, to a lesser extent, male HAB rats show high and abnormal forms of aggression compared with non-selected (NAB) rats, making them a suitable animal model for studying excessive aggression in the context of extremes in innate anxiety. In addition, we will discuss differences in the activity of the hypothalamic–pituitary–adrenal axis, brain arginine vasopressin, and the serotonin systems, among others, which contribute to the distinct behavioural phenotypes related to aggression and anxiety. Further investigation of the neurobiological systems in animals with distinct anxiety phenotypes might provide valuable information about the link between excessive aggression and disturbed emotional regulation, which is essential for understanding the social and emotional deficits that are characteristic of many human psychiatric disorders.

Depression research: where are we now?

Extensive studies have led to a variety of hypotheses for the molecular basis of depression and related mood disorders, but a definite pathogenic mechanism has yet to be defined. The monoamine hypothesis, in conjunction with the efficacy of antidepressants targeting monoamine systems, has long been the central topic of depression research. While it is widely embraced that the initiation of antidepressant efficacy may involve acute changes in monoamine systems, apparently, the focus of current research is moving toward molecular mechanisms that underlie long-lasting downstream changes in the brain after chronic antidepressant treatment, thereby reaching for a detailed view of the pathophysiology of depression and related mood disorders. In this minireview, we briefly summarize major themes in current approaches to understanding mood disorders focusing on molecular views of depression and antidepressant action.

5HT1A-mediated stimulation of cortisol release in major depression: use of non-invasive cortisol measurements to predict clinical response

The purpose of the present study was to explore 5HT1A-mediated cortisol release in major depressive disorder (MDD) patients in order to determine whether the degree of 5HT1A-receptor sensitivity can predict response to treatment with selective serotonin reuptake inhibitors (SSRIs). We examined whether the sensitivity of the 5HT1A receptor, as measured by the difference in salivary cortisol levels immediately before and 90 min following the administration of a single dose of the 5HT1A-selective agonist buspirone, predicted treatment outcome following an 8-week, fixed-dose, open trial of the SSRI escitalopram in 17 outpatients with MDD. Change in cortisol levels before and 90 min after the administration of buspirone were not found to predict treatment outcome, whether defined as clinical response (50% or greater reduction in symptom severity), or remission of symptoms. In conclusion, in the present study, we did not find that the change in salivary cortisol levels following the administration of a 5HT1A-selective agonist predicted treatment outcome following an 8-week, fixed-dose, open-label trial of the SSRI escitalopram among outpatients with MDD. Although the 5HT1A-desensitization hypothesis is still a valid one, the results of the present study could not provide any evidence in support.

Chronic exogenous corticosterone administration generates an insulin-resistant brain state in rats

We investigated whether long-term administration of exogenous corticosterone (CST) or vehicle as daily treatment induces changes in rat behavior and in gene expression of the rat brain insulin signaling pathway and the formation of tau protein. Two groups of male adult rats received daily subcutaneous injections of 26.8 mg/kg CST (CST stress group) or vehicle-sesame oil (injection stress group) for 60 days while the third group was taken as untreated controls (n = 8 each). Body weight and plasma CST were measured and psychometric investigations were conducted using a rat holeboard test system before and after the treatment. Gene expression analyzes were performed by RT-PCR in cerebral cortical tissue for insulin genes 1 and 2, insulin receptor (IR), insulin degrading enzyme (IDE), and tau protein. Daily injections of CST for 60 days induced a significant, 2-fold increase in rat plasma CST concentrations in comparison to untreated controls. Significantly reduced behavioral abilities in CST-treated rats were associated with reduced gene expression of insulin 1 ( - 20%), IDE ( - 23%), and IR ( - 26%), indicating an insulin-resistant brain state, followed by increased tau protein (+28%) gene expression. In summary, chronic CST administration affects gene expression in the brain IR signaling cascade and increases tau gene expression, which is associated with reductions in cognition capacity in rats.

Corticosterone urinalysis and nicotinic receptor modulation in rats

A routine method of measuring circulating corticosterone (CORT) levels in rats involves sampling of plasma from cannulated animals. However, being somewhat invasive, this method can potentially be confounded by its inherently stressful nature. This study investigated the feasibility of measuring corticosterone using a non-invasive sampling method from voided urine of male rats. Reliability was assessed pharmacologically with nicotinic compounds previously demonstrated to modulate plasma glucocorticoid levels. Nicotine (0.1-1mg/kg sc) dose-dependently increased corticosterone levels in rat urine at 30-70 min following administration. The short-lived nature of this elevation was confirmed as CORT levels measured 6 and 24h later were shown to have returned to basal levels. Both basal and nicotine-induced (0.5mg/kg sc) elevations in urinary CORT were consistent between groups of animals with weights ranging from 200 to 400 g. The magnitude of urinary CORT elevation induced by nicotine (0.5mg/kg sc) was found to be similar to that induced by a forced swim stressor in male Lister ) antagonist mecamylamine (0.05-0.5mg/kg sc) dose-dependently reversed the effects of nicotine (0.5mg/kg sc) on urinary CORT. Finally, the alpha(4)beta(2)-subunit preferring agonist TC-2559 induced a dose-dependent increase in CORT, whereas alpha(7)- and beta(4)-subunit preferring ligands had no effect, suggestive of the potential for differential involvement of nicotinic receptor subtypes in the mediation of this response. In conclusion, urinary corticosterone sampling in rats represents a robust assay sensitive to experimental manipulations of both pharmacological and behavioural relevances.

Histories of major depression and premenstrual dysphoric disorder: Evidence for phenotypic differences

This study examined unique versus shared stress and pain-related phenotypes associated with premenstrual dysphoric disorder (PMDD) and prior major depressive disorder (MDD). Sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA)-axis measures were assessed at rest and during mental stress, as well as sensitivity to cold pressor and tourniquet ischemic pain tasks in four groups of women: (1) non-PMDD with no prior MDD (N=18); (2) non-PMDD with prior MDD (N=9); (3) PMDD with no prior MDD (N=17); (4) PMDD with prior MDD (N=10). PMDD women showed blunted SNS responses to stress compared to non-PMDD women, irrespective of prior MDD; while women with prior MDD showed exaggerated diastolic blood pressure responses to stress versus never depressed women, irrespective of PMDD. However, only in women with histories of MDD did PMDD women have lower cortisol concentrations than non-PMDD women, and only in non-PMDD women was MDD associated with reduced cold pressor pain sensitivity. These results suggest both unique phenotypic differences between women with PMDD and those with a history of MDD, but also indicate that histories of MDD may have special relevance for PMDD.

Is depression "evolutionary" or just "adaptive"? A comment

Some recent explanations of depression have suggested that it may be "evolutionary" in that there are advantages to the depressed individual which arise from some aspects of depressive symptomatology. While the depressive behaviour of withdrawal from the adverse environment may provide some immediate benefits to the depressed individual, thus making it potentially "adaptive" in the short-term, this does not fit the biological definition of "evolutionary". In fact, depression does not meet two of the three required criteria from natural selection in order to be evolutionary. Therefore, while some depressive behaviour may be advantageous for the depressed individual, and is therefore "adaptive" in an immediate sense, it cannot be accurately described as "evolutionary". Implications for research and clinical practice are discussed.

Borderline personality disorder: hypothalamus pituitary adrenal axis and findings from neuroimaging studies

Borderline personality disorder (BPD) is a complex and serious mental disorder that is commonly seen psychiatric practice. Although stress, especially early life stress, seems to be associated with the development of the disorder, there has been far less research on the function of the hypothalamic-pituitary-adrenal (HPA) axis in BPD, compared to other psychiatric disorders, such as major depressive disorder and post-traumatic stress disorder. Stress has been suggested to exert damaging effects on the brain, particularly the hippocampus; therefore, neuroimaging studies yield important insight into the neurobiology of BPD. This article reviews research on the HPA axis and neuroimaging studies in BPD and aims to integrate these findings.

Hypothalamic--pituitary-- adrenal axis dysregulation in women with irritable bowel syndrome in response to acute physical stress

Irritable bowel syndrome (IBS) supports the concept of a dysregulated hypothalamic-pituitary-adrenal (HPA) axis. This study investigates the neuroendocrine and psychological responses to the acute physical stress of a lumbar puncture (LP) in women with diarrhea-predominant IBS by assessing central and peripheral HPA activity and affective measures. Blood samples have been collected at baseline and immediately post- and 1 hr following LP from 13 women with IBS and 13 controls. Plasma adrenocorticotropic hormone (ACTH), cortisol, epinephrine, and norepinephrine levels are analyzed. A single measure of cerebrospinal fluid (CSF) concentrations of corticotropin-releasing factor (CRF(CSF)) and norepinephrine(CSF) is noted. Affective assessments are used to rate anxiety and depression with the Hospital Anxiety and Depression Scale (HADS) and acute mood state is rated using the Stress Symptom Rating questionnaire (stress, anxiety, anger, arousal). The women with IBS display blunted ACTH and cortisol responses to the LP along with a profile of affective responsiveness suggestive of chronic psychosocial stress, although no CRF(CSF) differences between groups are observed.

Mechanism of St. John's wort extract (STW3-VI) during chronic restraint stress is mediated by the interrelationship of the immune, oxidative defense, and neuroendocrine system

Chronic stress is a contributing risk factor for the development of psychiatric illnesses such as anxiety and depression disorders. The aim of the present study was to evaluate the mechanisms of action of the standardized St. John's wort extract (STW3-VI; SJW) in a chronic restraint stress model. Markers of antioxidant capacity such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in the hippocampus and hypothalamus, and plasma levels of ACTH and corticosterone as well as the inflammatory markers IL-6 and TNF-alpha were determined in rats exposed to chronic restraint stress for 21 consecutive days. In addition, total body and relative organ weights as well as behavioral changes in the open field test were evaluated on the last day. The results show that stressed animals decreased in open field activity compared to unstressed animals, which could be reversed by fluoxetine (10mg/kg, p.o.) and SJW (125-750mg/kg, p.o.) treatment. In addition, chronic restraint stress significantly decreased thymus and spleen indices in the stressed control group. However, treating stressed rats with fluoxetine or STW3-VI produced a significant and dose dependent increase in both thymus and spleen indices compared to stressed controls. Additionally, SJW and fluoxetine significantly reduced stress-induced increases in plasma ACTH and corticosterone levels. Furthermore, the administration of SJW significantly reduced the stress-induced increase in TNF-alpha levels. Our data provide new evidence for the hypothesis that the mechanism of action of STW3-VI is mediated by the interrelationship between the immune, oxidative defense and neuroendocrine system.

Adverse early life experience and social stress during adulthood interact to increase serotonin transporter mRNA expression

Anxiety disorders, depression and animal models of vulnerability to a depression-like syndrome have been associated with dysregulation of serotonergic systems in the brain. To evaluate the effects of early life experience, adverse experiences during adulthood, and potential interactions between these factors on serotonin transporter (slc6a4) mRNA expression, we investigated in rats the effects of maternal separation (180 min/day from days 2 to 14 of life; MS180), neonatal handing (15 min/day from days 2 to 14 of life; MS15), or normal animal facility rearing (AFR) control conditions with or without subsequent exposure to adult social defeat on slc6a4 mRNA expression in the dorsal raphe nucleus (DR) and caudal linear nucleus. At the level of specific subdivisions of the DR, there were no differences in slc6a4 mRNA expression between MS15 and AFR rats. Among rats exposed to a novel cage control condition, increased slc6a4 mRNA expression was observed in the dorsal part of the DR in MS180 rats, relative to AFR control rats. In contrast, MS180 rats exposed to social defeat as adults had increased slc6a4 mRNA expression throughout the DR compared to both MS15 and AFR controls. Social defeat increased slc6a4 mRNA expression, but only in MS180 rats and only in the "lateral wings" of the DR. Overall these data demonstrate that early life experience and stressful experience during adulthood interact to determine slc6a4 mRNA expression. These data support the hypothesis that early life experience and major stressful life events contribute to dysregulation of serotonergic systems in stress-related neuropsychiatric disorders.

Neurobiological Pathways between Chronic Stress and Depression: Dysregulated Adaptive Mechanisms?

Stress-related diseases have been predicted to become major contributors to the Global Disease Burden within the next 20 years. Of these, depression is one of the principal identifiable sources of concern for public mental health, and has been hypothesized to be an outcome of prolonged stress. Examination of the hyper-responsiveness of the Hypothalamic-Pituitary-Adrenal axis, consequent elevated serum cortisol, plus the effects of this upon brain structure and function, provides a model for understanding how chronic stress may be a causal vector in the development of depression. Evidence from studies of the effectiveness of antidepressants aimed at reducing cortisol within depressed patients supports this model and suggests avenues for future research and treatment of stress-induced depression.

Status of glucocorticoid alterations in post-traumatic stress disorder

The current status of glucocorticoid alterations in post-traumatic stress disorder (PTSD) will be described in this chapter. Emphasis will be placed on data that suggest that at least some glucocorticoid-related observations in PTSD reflect pretraumatic glucocorticoid status. Recent observations have provided some evidence that pretraumatic glucocorticoid alterations may arise from genetic, epigenetic, and possibly other environmental influences that serve to increase the likelihood of developing PTSD following trauma exposure, as well as modulate attendant biological alterations associated with its pathophysiology. Current studies in the field of PTSD employ glucocorticoid challenge strategies to delineate effects of exogenously administered glucocorticoids on neuroendocrine, cognitive, and brain function. Results of these studies have provided an important rationale for using glucocorticoid strategies in the treatment of PTSD.

HPA axis reactivity in chronic pelvic pain: association with depression

OBJECTIVES

Chronic pelvic pain (CPP) is a frequent gynecological complaint. The pathophysiology of CPP is not fully understood. The aim of this study was to determine whether the presence of depressive symptoms is associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction in CPP.

METHODS

We measured neuroendocrine responses to a standardized social stress test and to a standard adrenocorticotropin (ACTH)(1-24) stimulation test in 18 patients with CPP, stratified based on the presence of high versus low self-reported depressive symptoms, compared with 24 controls.

RESULTS

Women with CPP and low depression exhibited enhanced ACTH responses to psychosocial stress compared with women with CPP and high depression, whereas there were no differences in cortisol responses. In the ACTH(1-24) stimulation test, CPP patients with high depression demonstrated enhanced cortisol responses.

CONCLUSION

These results suggest a relationship between self-reported depression and reactivity of the HPA axis in patients with CPP.

Anti-depressant and anxiolytic like behaviors in PKCI/HINT1 knockout mice associated with elevated plasma corticosterone level

BACKGROUND

Protein kinase C interacting protein (PKCI/HINT1) is a small protein belonging to the histidine triad (HIT) family proteins. Its brain immunoreactivity is located in neurons and neuronal processes. PKCI/HINT1 gene knockout (KO) mice display hyper-locomotion in response to D-amphetamine which is considered a positive symptom of schizophrenia in animal models. Postmortem studies identified PKCI/HINT1 as a candidate molecule for schizophrenia and bipolar disorder. We investigated the hypothesis that the PKCI/HINT1 gene may play an important role in regulating mood function in the CNS. We submitted PKCI/HINT1 KO mice and their wild type (WT) littermates to behavioral tests used to study anti-depressant, anxiety like behaviors, and goal-oriented behavior. Additionally, as many mood disorders coincide with modifications of hypothalamic-pituitary-adrenal (HPA) axis function, we assessed the HPA activity through measurement of plasma corticosterone levels.

RESULTS

Compared to the WT controls, KO mice exhibited less immobility in the forced swim (FST) and the tail suspension (TST) tests. Activity in the TST tended to be attenuated by acute treatment with valproate at 300 mg/kg in KO mice. The PKCI/HINT1 KO mice presented less thigmotaxis in the Morris water maze and spent progressively more time in the lit compartment in the light/dark test. In a place navigation task, KO mice exhibited enhanced acquisition and retention. Furthermore, the afternoon basal plasma corticosterone level in PKCI/HINT1 KO mice was significantly higher than in the WT.

CONCLUSION

PKCI/HINT1 KO mice displayed a phenotype of behavioral and endocrine features which indicate changes of mood function, including anxiolytic-like and anti-depressant like behaviors, in conjunction with an elevated corticosterone level in plasma. These results suggest that the PKCI/HINT 1 gene could be important for the mood regulation function in the CNS.

Adverse experience during early life and adulthood interact to elevate tph2 mRNA expression in serotonergic neurons within the dorsal raphe nucleus

Anxiety disorders, depression and animal models of vulnerability to a depression-like syndrome have been associated with dysregulation of brain serotonergic systems. These effects could result from genetic influences, adverse early life experiences (ELE), or acute stressful life events, all of which can alter serotonergic neurotransmission and have been implicated in determining vulnerability to neuropsychiatric disorders. To evaluate the effects of ELE, adverse experiences during adulthood, and potential interactions between these factors on neuronal tryptophan hydroxylase 2 (tph2) mRNA expression, we investigated in rats the effects of maternal separation (MS)(separation from the dam for 180 min/day from postnatal day 2-14; MS180, a model of vulnerability to a depression-like syndrome), neonatal handling (separation from the dam for 15 min/day from postnatal day 2-14; MS15, a model of decreased stress sensitivity), or normal animal facility rearing (AFR) control conditions, with or without subsequent exposure to adult social defeat, on tph2 mRNA expression in the dorsal raphe nucleus (DR). Among rats exposed to social defeat, MS180 rats had increased tph2 mRNA expression in the DR, while MS15 rats had decreased tph2 mRNA expression compared to AFR rats. Social defeat increased tph2 mRNA expression, but only in MS180 rats and only in the "lateral wings" of the DR, a subdivision of the DR that is part of a sympathomotor command center. Overall, these data demonstrate that ELE and stressful experience during adulthood interact to determine tph2 mRNA expression. These changes in tph2 mRNA expression represent a potential mechanism through which adverse ELEs and stressful life experiences during adulthood may interact to increase vulnerability to stress-related psychiatric disease.

Depression, cortisol, and suppressed cell-mediated immunity in metastatic breast cancer

Cancer treatment is known to have significant immuno-suppressive/dysregulatory effects. Psychological distress and depression, which often accompany cancer diagnosis and treatment, can also suppress or dysregulate endocrine and immune function. Cell-mediated immunity (CMI) is critical for protection against a host of pathogens to which cancer patients may be particularly susceptible. CMI is also important for defense against some tumors. This study explored relationships among depressive symptoms, cortisol secretion, and CMI responses in 72 women with metastatic breast cancer. Depressive symptoms were assessed with the Center for Epidemiologic Studies-Depression Scale (CES-D). Saliva was sampled throughout the day over a 3-day period to obtain a physiologic index of diurnal cortisol concentrations and rhythmicity, which is associated with breast cancer survival time. CMI for specific antigens was measured following intradermal administration of seven commonly encountered antigens (tuberculin, tetanus, diphtheria, Streptococcus, Candida, Trichophyton, and Proteus). Analyses adjusting for relevant medical and treatment variables indicated that women reporting more depressive symptoms showed suppressed immunity as measured by lower average induration size. Women with higher mean diurnal cortisol concentrations also showed suppressed immunity as indicated by a decreased number of antigens to which positive reactions were measured. This study highlights the relationships among depression, stress, and immune function in the context of advanced breast cancer.

Gene-environment interactions predict cortisol responses after acute stress: implications for the etiology of depression

BACKGROUND

Growing evidence suggests that the serotonin transporter polymorphism (5-HTTLPR) interacts with adverse environmental influences to produce an increased risk for the development of depression while the underlying mechanisms of this association remain largely unexplored. As one potential intermediate phenotype, we investigated alterations of hypothalamic-pituitary-adrenal (HPA) axis responses to stress in individuals with no history of psychopathology depending on both 5-HTTLPR and stressful life events.

METHODS

Healthy male adults (N=100) were genotyped and completed a questionnaire on severe stressful life events (Life Events Checklist). To test for gene-by-environment interactions on endocrine stress reactivity, subjects were exposed to a standardized laboratory stress task (Public Speaking). Saliva cortisol levels were obtained at 6 time points prior to the stressor and during an extended recovery period.

RESULTS

Subjects homozygous for the s-allele with a significant history of stressful life events exhibited markedly elevated cortisol secretions in response to the stressor compared to all other groups, indicating a significant gene-by-environment interaction on endocrine stress reactivity. No main effect of either 5-HTTLPR (biallelic and triallelic) or stressful life events on cortisol secretion patterns appeared.

CONCLUSION

This is the first study reporting that 5-HTTLPR and stressful life events interact to predict endocrine stress reactivity in a non-clinical sample. Our results underpin the potential moderating role of HPA-axis hyper-reactivity as a premorbid risk factor to increase the vulnerability for depression in subjects with low serotonin transporter efficiency and a history of severe life events.