The stress system in depression and neurodegeneration: focus on the human hypothalamus

Which patient will feel down, which will be happy? The need to study the genetic disposition of emotional states

PURPOSE

In quality-of-life (QL) research, the genetic susceptibility of negative and positive emotions is frequently ignored, taken for granted, or treated as noise. The objectives are to describe: (1) the major findings of studies addressing the heritable and environmental causes of variation in negative and positive emotional states and (2) the major biological pathways of and genetic variants involved in these emotional states.

METHODS

Literature overview.

RESULTS

The heritability estimates for anxiety and depression are 30-40%. Related traits as neuroticism and loneliness are also highly heritable. The hypothalamo-pituitary-adrenal axis is the 'final common pathway' for most depressive symptoms. The many findings of investigated genes are promising but not definitive. Heritability estimates of positive emotional states range between 40 and 50%. Life satisfaction and mental health share common genetic factors with optimism and self-esteem. The prefrontal cortex is a candidate brain area for positive emotional states. Biological and genetic research into positive emotional states is scarce.

CONCLUSION

Genetically informative studies may provide insights into a wide variety of complex questions that traditional QL studies cannot deliver. This insight in turn will help us to design more effective supportive programs that could moderate the outcomes of genetically based predispositions.

Changes in key hypothalamic neuropeptide populations in Huntington disease revealed by neuropathological analyses

Huntington disease (HD) is a fatal neurodegenerative disorder caused by expansion of a CAG repeat in the HD gene. Degeneration concentrating in the basal ganglia has been thought to account for the characteristic psychiatric symptoms, cognitive decline and motor dysfunction. However, the homeostatic control of emotions and metabolism are disturbed early in HD, and focused studies have identified a loss of orexin (hypocretin) neurons in the lateral hypothalamus in HD patients. There has been limited assessment of other hypothalamic cell populations that may be involved. In this study, we quantified the neuropeptide-expressing hypothalamic neurons known to regulate metabolism and emotion in patients with HD compared to healthy controls using unbiased stereological methods. We confirmed the loss of orexin-expressing neurons in HD and revealed substantial differences in the peptide expression of other neuronal populations in the same patients. Both oxytocin- and vasopressin-expressing neurons were decreased by 45 and 24%, respectively, while the number of cocaine- and amphetamine-regulated transcript (CART)-expressing neurons was increased by 30%. The increased expression of CART in the hypothalamus is consistent with a previous study showing increased CART levels in cerebrospinal fluid from HD patients. There was no difference in the numbers of neuropeptide Y-expressing neurons. These results show significant and specific alterations in the peptide expression of hypothalamic neurons known to regulate metabolism and emotion. They may be important in the development of psychiatric symptoms and metabolic disturbances in HD, and may provide potential targets for therapeutic interventions.

Expression patterns of corticotropin-releasing factor, arginine vasopressin, histidine decarboxylase, melanin-concentrating hormone, and orexin genes in the human hypothalamus

The hypothalamus regulates numerous autonomic responses and behaviors. The neuroactive substances corticotropin-releasing factor (CRF), arginine-vasopressin (AVP), histidine decarboxylase (HDC), melanin-concentrating hormone (MCH), and orexin/hypocretins (ORX) produced in the hypothalamus mediate a subset of these processes. Although the expression patterns of these genes have been well studied in rodents, less is known about them in humans. We combined classical histological techniques with in situ hybridization histochemistry to produce both 2D and 3D images and to visually align and quantify expression of the genes for these substances in nuclei of the human hypothalamus. The hypothalamus was arbitrarily divided into rostral, intermediate, and caudal regions. The rostral region, containing the paraventricular nucleus (PVN), was defined by discrete localization of CRF- and AVP-expressing neurons, whereas distinct relationships between HDC, MCH, and ORX mRNA-expressing neurons delineated specific levels within the intermediate and caudal regions. Quantitative mRNA signal intensity measurements revealed no significant differences in overall CRF or AVP expression at any rostrocaudal level of the PVN. HDC mRNA expression was highest at the level of the premammillary area, which included the dorsomedial and tuberomammillary nuclei as well as the dorsolateral hypothalamic area. In addition, the overall intensity of hybridization signal exhibited by both MCH and ORX mRNA-expressing neurons peaked in distinct intermediate and caudal hypothalamic regions. These results suggest that human hypothalamic neurons involved in the regulation of the HPA axis display distinct neurochemical patterns that may encompass multiple local nuclei.

Cortisol and depressive symptoms in a population-based cohort of midlife women

OBJECTIVE

To determine whether there is a relationship between depressive symptoms and cortisol assessed at first morning awakening, 6 PM, and 9 PM in a population-based sample of midlife women. If this relationship is not linear, we aim to test whether this relationship is nonlinear, only present in those with more severe depressive symptoms, better accounted for by diurnal slope, or only apparent under uncontaminated conditions.

METHODS

We investigated the cross-sectional association between cortisol and depressive symptoms, assessed by the Center for Epidemiological Studies Depression scale (CES-D) in 408 midlife women (45.7% African Americans, 54.3% white; mean age, 50.4 years) participating in the Chicago site of the Study of Women's Health Across the Nation.

RESULTS

Diurnal cortisol slope is significantly flatter for women with higher CES-D scores than for less depressed women (p < .05 for the interaction). This relationship remains significant even after adjusting for age, smoking status, race, education, income, menopausal status, hormone replacement therapy, body mass index, medications, and wake time, as well as possibly contaminating factors, including physical activity, smoking, eating, or caffeine or alcohol consumption before saliva collection. Results using depression assessed categorically (CES-D cutoff ≥16) were similar to those using continuous depression in both unadjusted and adjusted analyses (p = .005 for the interaction of CES-D by time).

CONCLUSIONS

In this population-based sample of midlife women, greater depressive symptoms were associated with a significantly flatter diurnal cortisol slope than those with fewer symptoms, even after adjusting for covariates and possibly contaminating behaviors.

Dendritic cell nuclear protein-1, a novel depression-related protein, upregulates corticotropin-releasing hormone expression

The recently discovered dendritic cell nuclear protein-1 is the product of a novel candidate gene for major depression. The A allele encodes full-length dendritic cell nuclear protein-1, while the T allele encodes a premature termination of translation at codon number 117 on chromosome 5. In the present study we investigate whether the two forms of dendritic cell nuclear protein-1 might act on corticotropin-releasing hormone, which plays a crucial role in the stress response and in the pathogenesis of depression. The messenger RNA expression of dendritic cell nuclear protein-1 appeared to be increased in the laser micro-dissected paraventricular nucleus of patients with depression compared with control subjects. Dendritic cell nuclear protein-1 was also found to be co-localized with corticotropin-releasing hormone in paraventricular nucleus neurons. Moreover, full-length dendritic cell nucleus protein-1 bound to and transactivated the promoter of corticotropin-releasing hormone in human embryonic kidney 293 cells. We propose that full-length dendritic cell nucleus protein-1 may play a role in the pathogenesis of depressive disorders by enhancing corticotropin-releasing hormone expression in the hypothalamic paraventricular nucleus.

Hypothalamic-pituitary-adrenal axis dysregulation in dysphoric children and adolescents: cortisol reactivity to psychosocial stress from preschool through middle adolescence

BACKGROUND

Most depressed adults exhibit dysregulation of the hypothalamic-pituitary-adrenal axis, including cortisol hyperreactivity to psychosocial challenge. In contrast, remarkably little is known about hypothalamic-pituitary-adrenal axis activity in response to psychosocial challenge among at-risk children and adolescents. This study examined cortisol response to psychosocial challenge in nondepressed, at-risk, dysphoric and nondysphoric control youth across different developmentally salient age groups (preschool, third-, sixth-, and ninth-graders).

METHODS

Two samples of youth (Study 1-preschoolers; Study 2-third-, sixth-, and ninth-graders) without a history of clinical depression were administered developmentally appropriate psychosocial challenges. Of these nondepressed children, we examined youth at high-risk (n = 60) and low-risk (n = 223) status, as defined by elevated but subthreshold dysphoric symptoms according to multiple informants. Cortisol levels were assessed before and after a psychosocial stressor.

RESULTS

Nondysphoric control youth at all ages displayed the expected cortisol rise to challenge followed by return to baseline. However, prepubertal, at-risk, dysphoric children--specifically preschoolers and third-graders--exhibited cortisol hyporeactivity to challenge, whereas postpubertal dysphoric adolescents (ninth-graders) displayed hyperreactivity to the stressor. Additional analyses revealed that this switch from cortisol hyporeactivity to hyperreactivity among at-risk, dysphoric youth occurred as a function of pubertal development.

CONCLUSIONS

Findings suggest a developmental switch in cortisol response for at-risk, dysphoric youth from preschool through adolescence and have implications for a developmental pathophysiological understanding of how at-risk youth across the lifespan might develop depressive disorder.

Chronic variable stress induces oxidative stress and decreases butyrylcholinesterase activity in blood of rats

Depressive disorders, including major depression, are serious and disabling, whose mechanisms are not clearly understood. Since life stressors contribute in some fashion to depression, chronic variable stress (CVS) has been used as an animal model of depression. In the present study we evaluated some parameters of oxidative stress [thiobarbituric acid reactive substances (TBARS), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)], and inflammatory markers (interleukin 6, C reactive protein, tumor necrosis factor-alpha and nitrites), as well as the activity of butyrylcholinesterase in blood of rats subjected to chronic stress. Homocysteine and folate levels also were measured. Stressed animals were submitted to different mild stressors for 40 days. After CVS, a reduction in weight gain was observed in the stressed group, as well as an increase in immobility time in the forced swimming test as compared with controls. Stressed animals presented a significant increase on TBARS and SOD/CAT ratio, but stress did not alter GPx activity and any inflammatory parameters studied. CVS caused a significant inhibition on serum butyrylcholinesterase activity. Stressed rats had higher plasmatic levels of homocysteine without differences in folate levels. Although it is difficult to extrapolate our findings to the human condition, the alterations observed in this work may be useful to help to understand, at least in part, the pathophysiology of depressive disorders.

Roles for gamma-aminobutyric acid in the development of the paraventricular nucleus of the hypothalamus

The development of the hypothalamic paraventricular nucleus (PVN) involves several factors that work together to establish a cell group that regulates neuroendocrine functions and behaviors. Several molecular markers were noted within the developing PVN, including estrogen receptors (ER), neuronal nitric oxide synthase (nNOS), and brain-derived neurotrophic factor (BDNF). By contrast, immunoreactive gamma-aminobutyric acid (GABA) was found in cells and fibers surrounding the PVN. Two animal models were used to test the hypothesis that GABA works through GABA(A) and GABA(B) receptors to influence the development of the PVN. Treatment with bicuculline to decrease GABA(A) receptor signaling from embryonic day (E) 10 to E17 resulted in fewer cells containing immunoreactive (ir) ERalpha in the region of the PVN vs. control. GABA(B)R1 receptor subunit knockout mice were used to examine the PVN at P0 without GABA(B) signaling. In female but not male GABA(B)R1 subunit knockout mice, the positions of cells containing ir ERalpha shifted from medial to lateral compared with wild-type controls, whereas the total number of ir ERalpha-containing cells was unchanged. In E17 knockout mice, ir nNOS cells and fibers were spread over a greater area. There was also a significant decrease in ir BDNF in the knockout mice in a region-dependent manner. Changes in cell position and protein expression subsequent to disruption of GABA signaling may be due, in part, to changes in nNOS and BDNF signaling. Based on the current study, the PVN can be added as another site where GABA exerts morphogenetic actions in development.

Estrogen actions in the brain and the basis for differential action in men and women: a case for sex-specific medicines

The classic view of estrogen actions in the brain was confined to regulation of ovulation and reproductive behavior in the female of all mammalian species studied, including humans. Burgeoning evidence now documents profound effects of estrogens on learning, memory, and mood as well as neurodevelopmental and neurodegenerative processes. Most data derive from studies in females, but there is mounting recognition that estrogens play important roles in the male brain, where they can be generated from circulating testosterone by local aromatase enzymes or synthesized de novo by neurons and glia. Estrogen-based therapy therefore holds considerable promise for brain disorders that affect both men and women. However, as investigations are beginning to consider the role of estrogens in the male brain more carefully, it emerges that they have different, even opposite, effects as well as similar effects in male and female brains. This review focuses on these differences, including sex dimorphisms in the ability of estradiol to influence synaptic plasticity, neurotransmission, neurodegeneration, and cognition, which, we argue, are due in a large part to sex differences in the organization of the underlying circuitry. There are notable sex differences in the incidence and manifestations of virtually all central nervous system disorders, including neurodegenerative disease (Parkinson's and Alzheimer's), drug abuse, anxiety, and depression. Understanding the cellular and molecular basis of sex differences in brain physiology and responses to estrogen and estrogen mimics is, therefore, vitally important for understanding the nature and origins of sex-specific pathological conditions and for designing novel hormone-based therapeutic agents that will have optimal effectiveness in men or women.

Secretagogue type, sex-steroid milieu, and abdominal visceral adiposity individually determine secretagogue-stimulated cortisol secretion

DESIGN

While androgens and estrogens control glucocorticoid secretion in animal models, how the sex-steroid milieu determines cortisol secretion in humans is less clear. To address this issue, cortisol was measured in archival sera obtained at 10-min intervals for 5 h in 42 healthy men administered double placebo, placebo and testosterone, testosterone and dutasteride (to block 5alpha-reductases type I and type II), or testosterone and anastrozole (to block aromatase) in a double-blind, placebo-controlled, prospectively randomized design.

METHODS

Subjects received i.v. injection of saline, GHRH, GH-releasing peptide-2 (GHRP-2), somatostatin (SS), and GHRP-2/GHRH/l-arginine (triple stimulus) each on separate mornings fasting. Outcomes comprised cortisol concentrations, pulsatile cortisol secretion, and relationships with age or abdominal visceral fat (AVF).

RESULTS

By ANCOVA, baseline (saline-infused) cortisol concentrations (nmol/l) did not differ among the sex-steroid milieus (overall mean 364+/-14). In contrast, stimulated peak cortisol concentrations were strongly determined by secretagogue type (P<0.001) as follows: triple stimulus (868+/-27)>GHRP-2 (616+/-42)>saline=SS=GHRH (grand mean 420+/-21). After GHRP-2 injection, pulsatile cortisol secretion increased with age (R(2)=0.16, P=0.012). After the triple stimulus, pulsatile cortisol secretion correlated i) inversely with serum 5alpha-dihydrotestosterone (DHT) concentrations (R(2)=0.53, P=0.026) and ii) directly with computerized tomography-estimated AVF (R(2)=0.11, P=0.038).

CONCLUSION

Age, DHT concentrations, AVF, and secretagogue type influence pulsatile cortisol secretion at least in men. Further studies should be performed to assess ACTH secretion and native ghrelin action in defined sex-steroid milieus.

Restraint stress-induced brain activation patterns in two strains of mice differing in their anxiety behaviour

Genetically identical inbred mouse strains are one of the most useful tools in dissecting the genetic basis of complex disorders. C57BL/6 and BALB/c mice differ markedly in emotionality. In particular, BALB/c mice are more stress-sensitive and have been proposed to be a model of pathological anxiety. There is a paucity of studies investigating whether brain activation in response to a stressor is different in these two strains. To this end, having confirmed that the strains differ in anxiety responses in a light-dark box test, we then examined if restraint stress induced increases in c-Fos protein expression in selective regions of the mouse brain. The areas of interest analysed were the paraventricular nucleus (PVN) of the hypothalamus, prefrontal cortex (PFC), the paraventricular thalamic nucleus (PV) and the hippocampus. These areas were chosen due to their known involvement in stress response. Our data demonstrate that BALB/c showed a similar cellular activation pattern to stress, with respect to c-Fos expression, in the PVN, PV and in the hippocampus. On the other hand, BALB/c showed markedly blunted stress-induced brain activation compared with stressed C57BL/6 mice in both the CG1 and CG2 regions of the PFC. The lower levels of stress-induced activity in high anxiety BALB/c mice, possibly indicate a circuit dysregulation at the cortico-limbic level in response to stress.

Interactions of the circadian CLOCK system and the HPA axis

Organisms have developed concurrent behavioral and physiological adaptations to the strong influence of day/night cycles, as well as to unforeseen, random stress stimuli. These circadian and stress-related responses are achieved by two highly conserved and interrelated regulatory networks, the circadian CLOCK and stress systems, which respectively consist of oscillating molecular pacemakers, the Clock/Bmal1 transcription factors, and the hypothalamic-pituitary-adrenal (HPA) axis and its end-effector, the glucocorticoid receptor. These systems communicate with one another at different signaling levels and dysregulation of either system can lead to development of pathologic conditions. In this review, we summarize the mutual physiologic interactions between the circadian CLOCK system and the HPA axis, and discuss their clinical implications.

Vasopressin and the output of the hypothalamic biological clock

The physiological effects of vasopressin as a peripheral hormone were first reported more than 100 years ago. However, it was not until the first immunocytochemical studies were carried out in the early 1970s, using vasopressin antibodies, and the discovery of an extensive distribution of vasopressin-containing fibres outside the hypothalamus, that a neurotransmitter role for vasopressin could be hypothesised. These studies revealed four additional vasopressin systems next to the classical magnocellular vasopressin system in the paraventricular and supraoptic nuclei: a sexually dimorphic system originating from the bed nucleus of the stria terminalis and the medial amygdala, an autonomic and endocrine system originating from the medial part of the paraventricular nucleus, and the circadian system originating from the hypothalamic suprachiasmatic nuclei (SCN). At about the same time as the discovery of the neurotransmitter function of vasopressin, it also became clear that the SCN contain the main component of the mammalian biological clock system (i.e. the endogenous pacemaker). This review will concentrate on the significance of the vasopressin neurones in the SCN for the functional output of the biological clock that is contained within it. The vasopressin-containing subpopulation is a characteristic feature of the SCN in many species, including humans. The activity of the vasopressin neurones in the SCN shows a pronounced daily variation in its activity that has also been demonstrated in human post-mortem brains. Animal experiments show an important role for SCN-derived vasopressin in the control of neuroendocrine day/night rhythms such as that of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes. The remarkable correlation between a diminished presence of vasopressin in the SCN and a deterioration of sleep-wake rhythms during ageing and depression make it likely that, also in humans, the vasopressin neurones contribute considerably to the rhythmic output of the SCN.

Current perspectives of the roles of the central norepinephrine system in anxiety and depression

Norepinephrine (NE) is a major monoamine neurotransmitter that has widespread effects across multiple brain areas to regulate arousal and stress responses. The underlying function of the NE cortical system is to balance vigilance/scanning behavior with focused attention on novel environmental stimuli and the state of arousal. The central NE system is involved intrinsically with the stress response system, and dysregulation within the NE system has been implicated in the pathogenesis of anxiety and depressive disorders. Central NE activity paradoxically has either anxiogenic or anxiolytic effects, depending on whether the time course of the stress is acute or chronic, whether the stress is predictable or unpredictable, and which underlying brain regions are affected. Under conditions of chronic stress, NE system activity dysregulation of the hypothalamic-pituitary-adrenal system may turn a homeostatic stress response into a pathological stress response. Data suggest that the NE interplay with the serotonin system may exert neurobiological normalization of the pathophysiological state of anxious depression. Accordingly, pharmacological interventions targeting the NE system can result in anxiolytic, rather than anxiogenic, outcomes when used to treat patients with anxiety and depression.

Neural mechanisms of ageing and cognitive decline

During the past century, treatments for the diseases of youth and middle age have helped raise life expectancy significantly. However, cognitive decline has emerged as one of the greatest health threats of old age, with nearly 50% of adults over the age of 85 afflicted with Alzheimer's disease. Developing therapeutic interventions for such conditions demands a greater understanding of the processes underlying normal and pathological brain ageing. Recent advances in the biology of ageing in model organisms, together with molecular and systems-level studies of the brain, are beginning to shed light on these mechanisms and their potential roles in cognitive decline.

Prolyl endopeptidase mRNA expression in the central nervous system during rat development

Prolyl endopeptidase (PEP) is a serine protease that cleaves small peptides at the carboxyl side of L-proline. PEP has been reported to have important functions in the brain being implicated in learning and memory processes, psychological disorders and neurodegenerative diseases. Several PEP substrates have been shown to play a role during brain development and this observation led us to investigate the expression of PEP mRNA in the rat brain and spinal cord, from embryo to adult stages. In situ hybridization revealed that PEP mRNA is expressed early, from embryonic day 15, notably in germinative areas including the neocortical, hippocampal, pallidal, thalamic, anterior hypothalamic, tectal, cerebellar, pontine and medullary neuroepithelia. PEP mRNA was also found in the differentiating fields of the olfactory bulb, the orbital and cingulate cortex, the hippocampal formation, the cortical plate and the subventricular zone of the cortex. Quantitative RT-PCR analysis in various brain areas and the spinal cord showed that PEP mRNA levels are more abundant during the perinatal stages, coinciding with a period of neuronal migration and differentiation. From then on, PEP mRNA expression decreased, reaching its lowest levels at adulthood. Overall, the present data support the possibility that PEP exerts specific functions related to neurodevelopment besides those proposed to date.

Corticotropin-Releasing Hormone, Glutamate, and γ-Aminobutyric Acid in Depression

Stress response and depression have a significant impact on modern society. Although the symptoms are well characterized, the molecular mechanisms underlying depression are largely unknown. The monoamine hypothesis, which postulates dysfunctional noradrenergic and serotonergic systems as the underlying primary cause of depression, has been valuable for the development of conventional antidepressants, which can reverse these dysfunctional states to some degree. However, recent data from various neuroscience disciplines have questioned the major role of amines in the pathogenesis of depression. A considerable amount of evidence has accumulated that suggests that normalization of the hypothalamo—pituitary—adrenal (HPA) system might be the final step necessary for a remission of depression. In addition, an increasing body of clinical and postmortem evidence is pointing to a role played by γ-aminobutyric acid (GABA) and glutamate in the etiology of depression. This review examines the evidence, mainly obtained from clinical studies or from postmortem brain material, for a major role of the HPA axis, glutamatergic, and GABAergic systems in the pathogenesis of major and bipolar depression. The authors hope that these insights will stimulate further studies with the final aim of developing new types of antidepressants that combine increased efficacy with a shorter delay of the onset of action and reduced side-effect profiles.

Mice overexpressing corticotropin-releasing factor show brain atrophy and motor dysfunctions

Chronic stress and persistently high glucocorticoid levels can induce brain atrophy. Corticotropin-releasing factor (CRF)-overexpressing (OE) mice are a genetic model of chronic stress with elevated brain CRF and plasma corticosterone levels and Cushing's syndrome. The brain structural alterations in the CRF-OE mice, however, are not well known. We found that adult male and female CRF-OE mice had significantly lower whole brain and cerebellum weights than their wild type (WT) littermates (347.7+/-3.6mg vs. 460.1+/-4.3mg and 36.3+/-0.8mg vs. 50.0+/-1.3mg, respectively) without sex-related difference. The epididymal/parametrial fat mass was significantly higher in CRF-OE mice. The brain weight was inversely correlated to epididymal/parametrial fat weight, but not to body weight. Computerized image analysis system in Nissl-stained brain sections of female mice showed that the anterior cingulate and sensorimotor cortexes of CRF-OE mice were significantly thinner, and the volumes of the hippocampus, hypothalamic paraventricular nucleus and amygdala were significantly reduced compared to WT, while the locus coeruleus showed a non-significant increase. Motor functions determined by beam crossing and gait analysis showed that CRF-OE mice took longer time and more steps to traverse a beam with more errors, and displayed reduced stride length compared to their WT littermates. These data show that CRF-OE mice display brain size reduction associated with alterations of motor coordination and an increase in visceral fat mass providing a novel animal model to study mechanisms involved in brain atrophy under conditions of sustained elevation of brain CRF and circulating glucocorticoid levels.

Icariin attenuates chronic mild stress-induced dysregulation of the LHPA stress circuit in rats

Chronic mild stress (CMS) is suggested to develop dysregulation of the limbic-hypothalamic-pituitary-adrenal (LHPA) stress circuit. Icariin, a major constituent of flavonoids isolated from Epimedium brevicornum, has been previously confirmed to rescue the HPA axis abnormalities in animal models of depression. However, antidepressant treatment of icariin on corticotropin-releasing factor (CRF) system within the LHPA stress circuit and its interaction with serotonergic receptor are still seldom studied in CMS model of animals. The present study further investigated the effects of CMS procedure and subsequent icariin treatment on mRNA and protein levels of CRF, CRF receptor 1 (CRFR1) and CRF binding protein (CRFBP), as well as sucrose intake in rats. Moreover, the levels of cyclic adenosine 3',5'-monophosphate (cAMP) response element binding protein (CREB), glucocorticoid receptor (GR) and 5-hydroxytryptamine 1A receptor (5-HTR1A) in hypothalamus, hippocampus and frontal cortex were simultaneously evaluated for their participations in CRF system in this model. We found that CMS procedure significantly increased CRF expression levels in the brain regions, and decreased GR and 5-HTR1A in hippocampus and frontal cortex, with sucrose intake reduction representing the hedonic deficit in rats. Icariin restored these alterations in CMS rats. These results confirmed the hypothesis that icariin exerted antidepressant-like effect via its regulation of central CRF system. And hippocampus was suggested as an important neural area controlling the LHPA stress circuit in icariin-treated CMS rats. These findings for the first time proved that the potential molecular mechanism of antidepressant action of icariin was targeted on the interaction of the LHPA stress circuit and serotonergic function in CMS rats.

Relation between neuritic plaques and depressive state in Alzheimer's disease

Meynen G, Van Stralen H, Smit JH, Kamphorst W, Swaab DF, Hoogendijk WJG. Relation between neuritic plaques and depressive state in Alzheimer's disease.

BACKGROUND

To investigate for the first time in a prospective study the relationship between depressive state and the neuropathological hallmarks of Alzheimer's disease, using a scale for depressive symptoms in dementia, while controlling for clinical severity of dementia.

METHOD

Within the framework of a prospective longitudinal study of depression in Alzheimer's disease, patients with dementia underwent a clinical evaluation every six months during the last years of their lives, using the Cornell scale for depression in dementia to assess depressive symptoms and using the Functional Assessment Staging scale to control for clinical severity of dementia. The brains of 43 Alzheimer patients were obtained. The last clinical evaluations prior to death together with post-mortem neuropathology measures were analysed.

RESULTS

We found a correlation between the Cornell scores and the sum score for the density of neuritic plaques in the entire cortex (p = 0.027), and even stronger in the temporal cortex (p = 0.012). The observed correlations were independent of sex, age of death, clinical dementia severity and duration of Alzheimer's disease.

CONCLUSIONS

This study shows a positive relationship between depressive state at time of death and the presence of neuritic plaques in Alzheimer's disease, which is independent of the clinical severity of dementia.

Disregarding clinical trial-based patient-reported outcomes is unwarranted: Five advances to substantiate the scientific stringency of quality-of-life measurement

BACKGROUND

The clinical impact of trial-based quality of life (QL) outcomes is frequently underestimated due, in part, to prejudice and lack of knowledge by the medical community. The objectives of this paper are to show that QL assessments build upon an empirically based and stringent approach to measurement and QL outcomes should not be viewed nor handled differently than any other parameter in medical research.

MATERIAL AND METHODS

Literature overview.

RESULTS

The objectives are substantiated with empirical evidence showing that: (1) existing QL measures are as reliable as most other clinical outcomes; (2) available guidelines improve the quality of trial-based QL data; (3) QL data have strong prognostic value for survival; (4) clinical significance of QL data can be established; and (5) accounting for response-shift effects in QL data over time is feasible. Finally, the investigation of the genetic disposition of QL is described as an emerging area of research.

DISCUSSION

It is a waste of effort and money and also unethical when collected trial-based QL data are not used to their full power. QL and other patient-reported outcomes deserve to be included in more trials, with full disclosure of all results, and standardized interpretation. Only the combined use of patient-reported and clinical outcomes will enable the examination of the extent to which cancer patients live a qualitatively good life as long as possible.

Identification of a potential molecular link between the glucocorticoid and serotonergic signaling systems

Glucocorticoid receptor (GR) and serotonin (5-hydroxytryptamine (5-HT)) signaling systems play a pivotal role in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis, but the molecular nature of interactions between these two systems remain largely unidentified. We used computational and experimental approaches to evaluate if DNA-protein interactions would provide a molecular link for the interaction between 5-HT and GR systems. Bioinformatic analysis identified nine binding sites in various serotonin receptors (HTR1D, HTR1F, HTR2A, HTR3A, and HTR6) for transcription factors in the GR family. Electrophoretic mobility shift assays (EMSA) using HeLa nuclear extract and purified full-length GR verified most of the predicted DNA-protein interactions. Six binding sites verified by EMSA results were evolutionarily conserved in multiple species. Multiple lines of evidence from computational and experimental analyses in this study support the potential of a molecular link between 5-HT and GR signaling systems. This finding provides new approaches to studies directed at mechanisms for glucocorticoid negative feedback regulation of the HPA axis involving 5-HT and interventional studies directed to neuropsychiatric diseases.

Brain volume abnormalities in major depressive disorder: a meta-analysis of magnetic resonance imaging studies

OBJECTIVE

So far, there have been no attempts to integrate the growing number of all brain volumetric magnetic resonance imaging studies in depression. In this comprehensive meta-analysis the magnitude and extent of brain volume differences between 2,418 patients with major depressive disorder and 1,974 healthy individuals from 64 studies was determined.

METHODS

A systematic research was conducted for volumetric magnetic resonance imaging studies of patients with major depressive disorder in relation to healthy control subjects. Studies had to report sufficient data for computation of effect sizes. For each study, the Cohen's d was calculated. All analyses were performed using the random effects model. Additionally, meta-regression analyses were done to explore the effects of potential sources of heterogeneity.

RESULTS

Patients showed large volume reductions in frontal regions, especially in the anterior cingulate and orbitofrontal cortex with smaller reductions in the prefrontal cortex. The hippocampus, the putamen and caudate nucleus showed moderate volume reductions.

CONCLUSIONS

This is the first comprehensive meta-analysis in major depressive disorder demonstrating structural brain abnormalities, particularly in those brain areas that are involved in emotion processing and stress-regulation.

Searching for the Anatomy of Dissociative Amnesia

Brain damage was traditionally seen as the product of a neurological disease or injury. Nevertheless, modern brain imaging techniques have provided increasing evidence for alterations in brain tissue and metabolism for a number of psychiatric disorders. Though for a while “dissociated” ( Spiegel, 2006 ) from the clinical and scientific arena, dissociative disorders have in the last several years received a renewed interest among several groups of researchers, who embarked on the work of disentangling their neural correlates. We review data from our own research as well as others, which point to distinct changes in brain regions underlying dissociative amnes(t)ic disorders. These changes may consist of overall reductions in brain metabolism or more selective alterations primarily in the right temporo-frontal cortices. Recent evidence with refined magnetic resonance imaging techniques furthermore reveals selective fiber degenerations in these regions. While these changes may persist and probably even intensify in some patients, they may be reversible in others – especially if treatment is carried out successfully within short time after onset. Implications of these findings for the pathogenetic conceptualization of dissociative amnes(t)ic disorders are outlined.

Photoperiodic regulation of retinoic acid signaling in the hypothalamus

Both retinoic acid (RA) and thyroid hormone (TH) regulate transcription via specific nuclear receptors. TH regulates hypothalamic homeostasis and active T3 is generated by deiodinase enzymes in tanycytes surrounding the third ventricle. However, RA has not been previously considered in such a role. Data presented here highlights novel parallels between the TH and RA synthetic pathways in the hypothalamus implying that RA also acts to regulate hypothalamic gene expression and function. Key elements of the RA cellular signaling pathway were shown to be regulated in the rodent hypothalamus. Retinoid synthetic enzymes and the retinol transport protein Stra6 were located in the cells lining the third ventricle allowing synthesis of RA from retinol present in the CNS to act via RA receptors and retinoid X receptors in the hypothalamus. Photoperiod manipulation was shown to alter the expression of synthetic enzymes and receptors with lengthening of photoperiod leading to enhanced RA signaling. In vitro RA can regulate the hypothalamic neuroendocrine peptide adrenocorticotrophic hormone. This work presents the new concept of controlled RA synthesis by hypothalamic tanycytes giving rise to possible involvement of this system in endocrine, and possibly vitamin A, homeostasis.

Brain vasopressin V(1) receptors contribute to enhanced cardiovascular responses to acute stress in chronically stressed rats and rats with myocardial infarcton

The present study was designed to determine the role of central vasopressin 1 receptors (V(1)R) in the regulation of cardiovascular parameters in chronically stressed infarcted rats and sham-operated rats under resting conditions and during exposure to acute alarming stress. The experiments were performed on four groups of conscious sham-operated and four groups of infarcted rats subjected to intraventricular infusion of either vehicle or a V(1)R antagonist (V(1)RANT). Two groups of infarcted and two groups of sham-operated rats were subjected to mild chronic stressing. Mean arterial blood pressure (MABP) and heart rate (HR) were determined under resting conditions and after exposure to acute stress (air jet). During vehicle infusion, MABP and HR increases in response to acute stress in the infarcted rats not subjected to chronic stress, and in the infarcted and sham-operated chronically stressed rats, were significantly greater than in the sham-operated rats not exposed to chronic stress. However, MABP and HR responses to acute stress in the chronically stressed infarcted rats and chronically stressed sham-operated rats did not differ. V(1)RANT abolished differences in cardiovascular responses to acute stress between the experimental groups. Resting cardiovascular parameters were not affected by any of the experimental treatments. It is concluded that chronic stressing enhances the pressor and tachycardic responses to acute stress in the sham-operated rats but does not further intensify these responses in infarcted rats.The results provide evidence that central V(1)Rs are involved in potentiation of cardiovascular responses to acute stress in chronically stressed rats, infarcted rats, and chronically stressed infarcted rats.

Cyclic AMP inducible early repressor mediates the termination of corticotropin releasing hormone transcription in hypothalamic neurons

Elevations of inducible cAMP early repressor (ICER), the repressor isoform of the cAMP-responsive element modulator (CREM), are associated with protein binding to the corticotrophin releasing hormone (CRH) promoter and termination of CRH transcriptional responses to stress. To determine whether endogenous ICER production represses CRH transcription, we examined the effect of CREM siRNA on forskolin-stimulated ICER formation and CRH transcription in the hypothalamic cell line, 4B, and in primary cultures of hypothalamic neurons. Cotransfection of 4B cells with CREM siRNA and a CRH promoter-driven luciferase reporter gene markedly reduced the induction of ICER by forskolin and potentiated the stimulatory effect of forskolin on CRH promoter activity, compared with cells cotransfected with a nonspecific oligonucleotide. The role of ICER on endogenous CRH expression was studied in primary cultures of hypothalamic neurons by examining the effect of CREM siRNA on forskolin-induced primary transcript (CRH hnRNA) using intronic real-time PCR. As observed during stress in vivo, forskolin-stimulated CRH hnRNA was transient, increasing up to 60 min and declining to near basal values by 3 h. Transfection of CREM siRNA reduced forskolin-induced ICER by about 45% 48-h later and partially reversed the declining phase of CRH hnRNA production at 3 h. The data provide evidence that endogenous ICER formation is required for termination of CRH transcription and support the hypothesis that ICER is part of an intracellular feedback mechanism limiting the activation of CRH transcription during stress.

Expression of circadian neuropeptides in the hypothalamus of adult mice is affected by postnatal light experience

The suprachiasmatic nuclei (SCN) of the hypothalamus are the principal pacemaker in mammals, controlling daily, circadian rhythms in physiology and behaviour. Environmental light during development has long-term effects on circadian behaviour, but it is still unclear what the relevant adaptations within the brain are. In the present study, we examined the manifestation of the circadian rhythm of locomotor activity, and the expression of arginine-vasopressin (AVP) and vasointestinal polypeptide (VIP) in the SCN of adult mice reared under different light environments during the suckling period, and synchronised to light/dark cycles after weaning. We found that animals reared under constant light had higher amplitude and more stable activity rhythms, together with lower levels of VIP- and AVP-immunostaining in the SCN, compared to mice reared under light/dark cycles or constant darkness. Differences in AVP expression were also found in the paraventricular nucleus and the supraoptic nucleus, two brain areas which receive SCN projections. These results indicate that the postnatal light experience may affect clock function and clock output, and suggest implications for the control of hormonal homeostasis and circadian behaviour.

Serum oxytocin levels in patients with depression and the effects of gender and antidepressant treatment

Abnormalities in the neurohypophyseal system have been reported in depression. This study aimed to investigate serum oxytocin levels in patients with depression and the effects of gender and antidepressant treatment on these levels. Serum oxytocin levels were measured before and after treatment with antidepressant drugs or electroconvulsive therapy (ECT) in 40 inpatients (30 women, 10 men) who met the DSM-IV criteria for major depressive disorder (n=29) or bipolar affective disorder depressive episode (n=11), and in 32 healthy controls (20 women, 12 men). Serum oxytocin levels were decreased both pre-treatment and post-treatment in the patients compared with those in the controls. Serum oxytocin levels were not affected by antidepressant drug treatment or ECT. The female patients had significantly lower oxytocin levels than the control females, whereas no difference was found between the male patients and the male controls. We found no difference in serum levels of oxytocin between the unipolar and bipolar depressive patients. Our result shows reduced oxytocin in depression and a gender difference in oxytocin levels. Furthermore, antidepressant treatments appear to have no effect on serum oxytocin levels.

Depression and Alzheimer's disease: neurobiological links and common pharmacological targets

Depression is one of the most prevalent and life-threatening forms of mental illnesses, whereas Alzheimer's disease is a neurodegenerative disorder that affects more than 37 million people worldwide. Recent evidence suggests a strong relationship between depression and Alzheimer's disease. A lifetime history of major depression has been considered as a risk factor for later development of Alzheimer's disease. The presence of depressive symptoms can affect the conversion of mild cognitive impairment into Alzheimer's disease. Neuritic plaques and neurofibrillary tangles, the two major hallmarks of Alzheimer's disease brain, are more pronounced in the brains of Alzheimer's disease patients with comorbid depression as compared with Alzheimer's disease patients without depression. On the other hand, neurodegenerative phenomena have been observed in different brain regions of patients with a history of depression. Recent evidence suggests that molecular mechanisms and cascades that underlie the pathogenesis of major depression, such as chronic inflammation and hyperactivation of hypothalamic-pituitary-adrenal (HPA) axis, are also involved in the pathogenesis of Alzheimer's disease. In particular, a specific impairment in the signaling of some neurotrophins such as transforming-growth-factor beta1 (TGF-beta1) and brain-derived neurotrophic factor (BDNF) has been observed both in depression and Alzheimer's disease. In the present review we will examine the evidence on the common molecular pathways between depression and Alzheimer's disease and we will discuss these pathways as new pharmacological targets for the treatment of both major depression and Alzheimer's disease.

The role of beta-endorphin in the pathophysiology of major depression

A role for beta-endorphin (beta-END) in the pathophysiology of major depressive disorder (MDD) is suggested by both animal research and studies examining clinical populations. The major etiological theories of depression include brain regions and neural systems that interact with opioid systems and beta-END. Recent preclinical data have demonstrated multiple roles for beta-END in the regulation of complex homeostatic and behavioural processes that are affected during a depressive episode. Additionally, beta-END inputs to regulatory pathways involving feeding behaviours, motivation, and specific types of motor activity have important implications in defining the biological foundations for specific depressive symptoms. Early research linking beta-END to MDD did so in the context of the hypothalamic-pituitary-adrenal (HPA) axis activity, where it was suggested that HPA axis dysregulation may account for depressive symptoms in some individuals. The primary aims of this paper are to use both preclinical and clinical research (a) to critically review data that explores potential roles for beta-END in the pathophysiology of MDD and (b) to highlight gaps in the literature that limit further development of etiological theories of depression and testable hypotheses. In addition to examining methodological and theoretical challenges of past clinical studies, we summarize studies that have investigated basal beta-END levels in MDD and that have used challenge tests to examine beta-END responses to a variety of experimental paradigms. A brief description of the synthesis, location in the CNS and behavioural pharmacology of this neuropeptide is also provided to frame this discussion. Given the lack of clinical improvement observed with currently available antidepressants in a significant proportion of depressed individuals, it is imperative that novel mechanisms be investigated for antidepressant potential. We conclude that the renewed interest in elucidating the role of beta-END in the pathophysiology of MDD must be paralleled by consensus building within the research community around the heterogeneity inherent in mood disorders, standardization of experimental protocols, improved discrimination of POMC products in analytical techniques and consistent attention paid to important confounds like age and gender.

The impact of vascular burden on late-life depression

Small vessel pathology and microvascular lesions are no longer considered as minor players in the fields of cognitive impairment and mood regulation. Although frequently found in cognitively intact elders, both neuroimaging and neuropathological data revealed the negative impact on cognitive performances of their presence within neocortical association areas, thalamus and basal ganglia. Unlike cognition, the relationship between these lesions and mood dysregulation is still a matter of intense debate. Early studies focusing on the role of macroinfarct location in the occurrence of post-stroke depression (PSD) led to conflicting data. Later on, the concept of vascular depression proposed a deleterious effect of subcortical lacunes and deep white matter demyelination on mood regulation in elders who experienced the first depressive episode. More recently, the chronic accumulation of lacunes in thalamus, basal ganglia and deep white matter has been considered as a strong correlate of PSD. We provide here a critical overview of neuroimaging and neuropathological sets of evidence regarding the affective repercussions of vascular burden in the aging brain and discuss their conceptual and methodological limitations. Based on these observations, we propose that the accumulation of small vascular and microvascular lesions constitutes a common neuropathological platform for both cognitive decline and depressive episodes in old age.

Assessing the neuroendocrine stress response in the functional neuroimaging context

Neural regulation of stress responses, and the feedback of stress hormones to the brain, reflect complex brain-body interactions that may underlie the effects of psychological stress on health. Elucidating the brain circuitry involved in the cortical control of limbic-hypothalamic-pituitary-adrenal axis, and the cortical "targets" of cortisol that in turn modulates brain function, requires careful assessment of glucocorticoid hormones, in the context of the neuroimaging paradigms. Here we discuss approaches for assessment of endocrine function in the context of neuroimaging, including methods of blood and saliva specimen collection, and methods for drug/hormone administration. We also briefly discuss important temporal considerations, including appropriate timing of sample collections for hormones with different time-courses of activation (e.g. ACTH vs. cortisol), the pharmacokinetics of both endogenous hormones and administered agents, and circadian considerations. These are crucial to experimental designs of rhythmic hormonal systems and multiple feedback loops. We briefly address psychological/behavioral 'activation' paradigms used for inducing endogenous LHPA axis responses within or in proximity to scanner, as well as strategies for administration of exogenous hormones or secretagogues. Finally, we discuss some of the analytical issues in terms of hormone responses (e.g. response and area under curve, diurnal variability) and strategies for linking measured levels of peripheral humoral factor to brain activity (e.g. hormone responses as between-subject regressors of BOLD activations, hormone levels as within-subject regressors in analyses of covariance of brain activity over time, etc.).

Modulation of glucocorticoid receptor nuclear translocation in neurons by immunophilins FKBP51 and FKBP52: implications for major depressive disorder

Mood disorders associated with dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis are common psychiatric conditions. The glucocorticoid receptor (GR) is a steroid-activated nuclear receptor that, upon binding to cortisol, translocates to the nucleus where it targets genes related to neuronal metabolism and plasticity. In patients suffering from major depressive disorder (MDD), hypercortisolemia is a common finding. In the current study we investigated the molecular events associated with the FK506 binding proteins (FKBP) -52 and -51 response to cortisol exposure in neuronal cell cultures and their effect on GR translocation. We noted that FK506 altered nuclear localization of the GR and inhibited expression of GR-responsive genes. Furthermore, siRNA knockdown of FKBP4 gene, coding for the immunophilin FKBP52, inhibited cortisol-activated GR nuclear translocation, while knockdown of FKBP5, coding for immunophilin FKBP51, was associated with increased baseline GR nuclear localization. We propose that immunophilins are modulators of the cortisol-HPA axis response to stress and related chronic brain disorders.

Interleukin-6 is elevated in the cerebrospinal fluid of suicide attempters and related to symptom severity

BACKGROUND

Depressive disorders are associated with immune system alterations that can be detected in the blood. Cytokine concentrations in cerebrospinal fluid (CSF) and their relationship to aspects of suicidality have previously not been investigated.

METHODS

We measured interleukin-1beta, interleukin-6 (IL-6), interleukin-8, and tumor necrosis factor-alpha (TNF-alpha) in CSF and plasma of suicide attempters (n = 63) and healthy control subjects (n = 47). Patients were classified according to diagnosis and violent or nonviolent suicide attempt. We evaluated suicidal ideation and depressive symptoms using the Suicide Assessment Scale and the Montgomery-Asberg Depression Rating Scale (MADRS). We also analyzed the relation between cytokines and monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in CSF, as well as the integrity of the blood-brain barrier as reflected by the CSF:serum albumin ratio.

RESULTS

IL-6 in CSF was significantly higher in suicide attempters than in healthy control subjects. Patients who performed violent suicide attempts displayed the highest IL-6. Furthermore, there was a significant positive correlation between MADRS scores and CSF IL-6 levels in all patients. IL-6 and TNF-alpha correlated significantly with 5-HIAA and HVA in CSF, but not with MHPG. Cytokine levels in plasma and CSF were not associated, and patients with increased blood-brain barrier permeability did not exhibit elevated cytokine levels.

CONCLUSIONS

We propose a role for CSF IL-6 in the symptomatology of suicidal behavior, possibly through mechanisms involving alterations of dopamine and serotonin metabolism.

Hypothalamic vasopressin and oxytocin mRNA expression in relation to depressive state in Alzheimer's disease: a difference with major depressive disorder

Arginine vasopressin (AVP) and oxytocin (OXT), produced in the hypothalamic paraventricular (PVN) and supraoptic nucleus (SON), are considered to be involved in the pathophysiology of major depressive disorder (MDD). The objective of this study was to determine, for the first time, the relationship between AVP and OXT gene expression and depressive state in Alzheimer's disease (AD). Post-mortem brain tissue was obtained from six control subjects, and from a prospectively studied cohort of 23 AD patients, using the DSM-IIIR and the Cornell Scale for Depression in Dementia to determine depression diagnosis and severity. The amount of AVP and OXT mRNA was determined by in situ hybridisation. AD patients did not differ from controls with respect to the amount of AVP or OXT mRNA in the PVN or SON. Also, no differences were found between depressed and nondepressed AD patients and no relationship was found between the depression severity and AVP or OXT mRNA expression. The results indicate that AVP and OXT gene expression in the PVN and SON is unchanged in depressed AD patients compared to nondepressed AD patients. This is in contrast with the enhanced AVP gene expression in MDD, suggesting a difference in pathophysiology between MDD and depression in AD.

Chronic stress- and sex-specific neuromorphological and functional changes in limbic structures

Chronic stress produces sex-specific neuromorphological changes in a variety of brain regions, which likely contribute to the gender differences observed in stress-related illnesses and cognitive ability. Here, we review the literature investigating the relationship between chronic stress and sex differences on brain plasticity and function, with an emphasis on morphological changes in dendritic arborization and spines in the hippocampus, prefrontal cortex, and amygdala. These brain structures are highly interconnected and sensitive to stress and gonadal hormones, and influence a variety of cognitive abilities. Although much less work has been published using female subjects than with male subjects, the findings suggest that the relationship between brain morphology and function is very different between the sexes. After reviewing the literature, we present a model showing how chronic stress influences the morphology of these brain regions and changes the dynamic of how these limbic structures interact with each other to produce altered behavioral outcomes in spatial ability, behavioral flexibility/executive function, and emotional arousal.

Focus on HTR2C: A possible suggestion for genetic studies of complex disorders

HTR2C is one of the most relevant and investigated serotonin receptors. Its role in important brain structures such as the midbrain, the lateral septal complex, the hypothalamus, the olfactory bulb, the pons, the choroid plexus, the nucleus pallidus, the striatum and the amygdala, the nucleus accumbens and the anterior cingulated gyrus candidate it as a promising target for genetic association studies. The biological relevance of these brain structures is reviewed by way of the focus on HTR2C activity, with a special attention paid to psychiatric disorders. Evidence from the genetic association studies that dealt with HTR2C is reviewed and discussed alongside the findings derived from the neuronatmic investigations. The reasons for the discrepancies between these two sets of reports are discussed. As a result, HTR2C is shown to play a pivotal role in many different psychiatric behaviors or psychiatric related disrupted molecular balances, nevertheless, genetic association studies brought inconsistent results so far. The most replicated association involve the feeding behavior and antipsychotic induced side effects, both weight gain and motor related: Cys23Ser (rs6318) and -759C/T (rs3813929) report the most consistent results. The lack of association found in other independent studies dampens the clinical impact of these reports. Here, we report a possible explanation for discrepant findings that is poorly or not at all usually considered, that is that HTR2C may exert different or even opposite activities in the brain depending on the structure analyzed and that mRNA editing activity may compensate possible genetically controlled functional effects. The incomplete coverage of the HTR2C variants is proposed as the best cost-benefit ratio bias to fix. The evidence of brain area specific HTR2C mRNA editing opens a debate about how the brain can differently modulate stress events, and process antidepressant treatments, in different brain areas. The mRNA editing activity on HTR2C may play a major role for the negative association results.

HPA axis hyperactivity and cardiovascular mortality in mood disorder inpatients

Depression is associated with an increased risk of cardiovascular disease (CVD), coronary heart disease (CHD) and cardiac death. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis function is frequent in major depression and hypercortisolemia may be a mediating factor in these relationships. The aim of this study was to assess HPA axis function measured with the dexamethasone suppression test (DST) in relation to CVD and CHD mortality in a cohort of 382 inpatients with mood disorder admitted to the department of Psychiatry at the Karolinska University Hospital between 1980 and 2000. Death certificates ascertained that 75 patients had died of cardiovascular disease and 30 patients of CHD during the mean follow-up of 18 years. DST non-suppression and higher baseline serum cortisol predicted CVD death. In male inpatients with mood disorder, the DST non-suppressor status was significantly associated with CVD death but not with CHD death. In depressed female inpatients the DST non-suppression was not associated with cardiovascular mortality. Baseline serum cortisol and post-dexamethasone serum cortisol levels at 4:00 p.m. showed a trend to be higher in female CVD/CHD victims. Effect of aging on HPA axis functioning was shown in male CHD deaths. HPA axis dysregulation may be a mediating factor between depression and increased risk of cardiovascular death in male mood disorder inpatients indicating that HPA-axis hyperactivity is a long term risk factor for cardiovascular mortality.

Through the looking glass: examining neuroanatomical evidence for cellular alterations in major depression

Alterations in brain plasticity are increasingly thought to play important roles in major depressive disorder (MDD) and suicide. To gain a better understanding of the gross structural changes observed in the brains of major depressed and suicide subjects, a number of recent investigations have scrutinized the cellular integrity of brain regions implicated in mood disorders. The purpose of this review is to summarize the current knowledge on the microscopic features of neuronal and glial cell populations in these different brain regions, namely the prefrontal cortex, hippocampus, amygdala, raphe nucleus and locus coeruleus. In general, evidence from this burgeoning field supports the hypothesis of altered cell plasticity in MDD and suicide occurring mainly in key fronto-limbic areas. Interestingly, reported morphometric and cell density alterations are generally region-specific and implicate several neuromodulatory systems, notably GABAergic, serotonergic, noradrenergic and glutamatergic pathways. Cell-specific changes involve reductions in densities of astrocytes and oligodendrocytes, while increases in microglial densities have also been reported. Furthermore, increases in neuronal densities have been found in subcortical regions. The implication of such findings for our understanding of the cellular and molecular underpinnings of MDD and suicide are discussed, and the strengths and weaknesses of morphological approaches used to analyse human postmortem brain tissues are evaluated.

HPA axis hyperactivity and attempted suicide in young adult mood disorder inpatients

BACKGROUND

Hyperactivity of the Hypothalamic-Pituitary-Adrenal (HPA) axis is a consistent finding in Major Depressive Disorder (MDD) and most prospective studies of HPA-axis function have found that non-suppressors in the dexamethasone suppression test (DST) are more likely to commit suicide during follow-up. The results of studies on HPA-axis function and attempted suicide are less consistent. Suicide attempts are more common among young people than the elderly, whereas suicide is more common among the elderly. The impact of age related changes in HPA-axis system activity in relation to suicidal behaviour across the lifecycle may be of importance.

METHODS

The aim of the present study was to investigate the DST results in 36 young adult (30 years or younger) inpatients with mood disorder, with (n=18) and without suicide attempt at the index episode.

RESULTS

The DST non-suppressor rate was 25% among young mood disorder inpatients. DST non-suppression was associated with suicide attempt and post-dexamethasone serum cortisol at 11:00 p.m. was significantly higher in suicide attempters compared to non-attempters. The DST non-suppressor rate was 39% in young adult suicide attempters compared with 11% in non-attempters.

CONCLUSIONS

The results add to previous evidence in support of the role of HPA axis hyperactivity and suicidal behaviour. The present findings motivate to include HPA axis measures in the assessment of depression in young adults.

Effects of neonatal handling on social memory, social interaction, and number of oxytocin and vasopressin neurons in rats

Early-life environmental events can induce profound long-lasting changes in several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces stress responses and sexual behavior in adult rats. The purpose of this study was to analyze the effects of neonatal handling on social behaviors of male and female rats in adulthood, as manifest by the results of social memory and social interaction tests. The number of oxytocin (OT) and vasopressin (VP) neurons in the paraventricular (PVN) and supraoptic (SON) nuclei of hypothalamus were also analyzed. The results did not demonstrate impairment of social memory. Notwithstanding, handling did reduce social investigative interaction and increase aggressive behavior in males, but did not do so in females. Furthermore, in both males and females, handling was linked with reduced number of OT-neurons in the parvocellular region of the PVN, while no differences were detected in the magnocellular PVN or the SON. On the other hand, handled males exhibited increased number of VP-neurons in the magnocellular zone of the PVN. We may conclude that the repeated brief maternal separations can reduce affiliative social behavior in adult male rats. Moreover, the disruption of the mother-infant relationship caused by the handling procedure induced long-lasting morphological changes in critical neuroendocrine areas that are involved in social bonding in mammals.

The establishment of the GENEQOL consortium to investigate the genetic disposition of patient-reported quality-of-life outcomes

To our knowledge, no comprehensive, interdisciplinary initiatives have been taken to examine the role of genetic variants on patient-reported quality-of-life outcomes. The overall objective of this paper is to describe the establishment of an international and interdisciplinary consortium, the GENEQOL Consortium, which intends to investigate the genetic disposition of patient-reported quality-of-life outcomes. We have identified five primary patient-reported quality-of-life outcomes as initial targets: negative psychological affect, positive psychological affect, self-rated physical health, pain, and fatigue. The first tangible objective of the GENEQOL Consortium is to develop a list of potential biological pathways, genes and genetic variants involved in these quality-of-life outcomes, by reviewing current genetic knowledge. The second objective is to design a research agenda to investigate and validate those genes and genetic variants of patient-reported quality-of-life outcomes, by creating large datasets. During its first meeting, the Consortium has discussed draft summary documents addressing these questions for each patient-reported quality-of-life outcome. A summary of the primary pathways and robust findings of the genetic variants involved is presented here. The research agenda outlines possible research objectives and approaches to examine these and new quality-of-life domains. Intriguing questions arising from this endeavor are discussed. Insight into the genetic versus environmental components of patient-reported quality-of-life outcomes will ultimately allow us to explore new pathways for improving patient care. If we can identify patients who are susceptible to poor quality of life, we will be able to better target specific clinical interventions to enhance their quality of life and treatment outcomes.

Increased orexin levels in the cerebrospinal fluid the first year after a suicide attempt

BACKGROUND

The orexins (hypocretins) and cocaine and amphetamine regulated transcript (CART) are hypothalamic peptides involved in the regulation of sleep and appetite. We have previously shown that levels of both orexin-A and CART in the cerebrospinal fluid (CSF) are related to specific psychiatric symptoms.

METHODS

Ten patients took part in lumbar punctures and psychiatric evaluations in conjunction to a suicide attempt and after 6 and 12 months. We measured CSF-orexin and CART using radioimmunoassays.

RESULTS

Mean CSF-orexin was significantly higher at the first and second follow-up than at the suicide attempt. In contrast, mean CSF-CART did not differ over time. Total SUAS scores, as well as ratings of CPRS item 66 (global illness) were significantly lower at follow-up. At one year, there was a significant negative correlation between the change in CSF-orexin and the change in total SUAS score.

LIMITATIONS

The number of patients who participated was relatively small.

CONCLUSIONS

Our results support the hypothesis that orexin is involved in psychiatric symptomatology.

The structural basis of gas-responsive transcription by the human nuclear hormone receptor REV-ERBbeta

Heme is a ligand for the human nuclear receptors (NR) REV-ERBalpha and REV-ERBbeta, which are transcriptional repressors that play important roles in circadian rhythm, lipid and glucose metabolism, and diseases such as diabetes, atherosclerosis, inflammation, and cancer. Here we show that transcription repression mediated by heme-bound REV-ERBs is reversed by the addition of nitric oxide (NO), and that the heme and NO effects are mediated by the C-terminal ligand-binding domain (LBD). A 1.9 A crystal structure of the REV-ERBbeta LBD, in complex with the oxidized Fe(III) form of heme, shows that heme binds in a prototypical NR ligand-binding pocket, where the heme iron is coordinately bound by histidine 568 and cysteine 384. Under reducing conditions, spectroscopic studies of the heme-REV-ERBbeta complex reveal that the Fe(II) form of the LBD transitions between penta-coordinated and hexa-coordinated structural states, neither of which possess the Cys384 bond observed in the oxidized state. In addition, the Fe(II) LBD is also able to bind either NO or CO, revealing a total of at least six structural states of the protein. The binding of known co-repressors is shown to be highly dependent upon these various liganded states. REV-ERBs are thus highly dynamic receptors that are responsive not only to heme, but also to redox and gas. Taken together, these findings suggest new mechanisms for the systemic coordination of molecular clocks and metabolism. They also raise the possibility for gas-based therapies for the many disorders associated with REV-ERB biological functions.

Risk of postpartum depressive symptoms with elevated corticotropin-releasing hormone in human pregnancy

CONTEXT

Postpartum depression (PPD) is common and has serious implications for the mother and her newborn infant. A possible link between placental corticotropin-releasing hormone (pCRH) and PPD incidence has been hypothesized, but empirical evidence is lacking.

OBJECTIVE

To determine whether accelerated increases in pCRH throughout pregnancy are associated with PPD symptoms.

DESIGN

Pregnant women were recruited into this longitudinal cohort study. Blood samples were obtained at 15, 19, 25, 31, and 37 weeks' gestational age (GA) for assessment of pCRH, cortisol, and adrenocorticotropic hormone (ACTH). Depressive symptoms were assessed with a standardized questionnaire at the last 4 pregnancy visits and post partum.

SETTING

Subjects were recruited from 2 southern California medical centers, and visits were conducted in research laboratories.

PARTICIPANTS

One hundred adult women with a singleton pregnancy. Main Outcome Measure Symptoms of PPD were assessed at a mean (SD) of 8.7 (2.94) weeks after delivery with the Edinburgh Postnatal Depression Scale.

RESULTS

Sixteen women developed PPD symptoms. At 25 weeks' GA, pCRH was a strong predictor of PPD symptoms (R(2) = 0.21; beta = 0.46 [P < .001]), an effect that remained significant after controlling for prenatal depressive symptoms. No significant associations were found for cortisol and ACTH. Receiver operating characteristic curve analyses revealed that pCRH at 25 weeks' GA is a possible diagnostic tool (area under the curve, 0.78 [P = .001]). Sensitivity (0.75) and specificity (0.74) at the ideal cutoff point (pCRH, 56.86 pg/mL) were moderate. Growth curve analyses indicated that the trajectories of pCRH in women with PPD symptoms are significantly accelerated from 23 to 26 weeks' GA.

CONCLUSIONS

At a critical period in midpregnancy, pCRH is a sensitive and specific early diagnostic test for PPD symptoms. If replicated, these results have implications for the identification and treatment of pregnant women at risk for PPD.