Neuroplasticity and cellular resilience in mood disorders

Glycogen synthase kinase-3 in the etiology and treatment of mood disorders

The mood disorders major depressive disorder and bipolar disorder are prevalent, are inadequately treated, and little is known about their etiologies. A better understanding of the causes of mood disorders would benefit from improved animal models of mood disorders, which now rely on behavioral measurements. This review considers the limitations in relating measures of rodent behaviors to mood disorders, and the evidence from behavioral assessments indicating that glycogen synthase kinase-3 (GSK3) dysregulation promotes mood disorders and is a potential target for treating mood disorders. The classical mood stabilizer lithium was identified by studying animal behaviors and later was discovered to be an inhibitor of GSK3. Several mood-relevant behavioral effects of lithium in rodents have been identified, and most have now been shown to be due to its inhibition of GSK3. An extensive variety of pharmacological and molecular approaches for manipulating GSK3 are discussed, the results of which strongly support the proposal that inhibition of GSK3 reduces both depression-like and manic-like behaviors. Studies in human postmortem brain and peripheral cells also have identified correlations between alterations in GSK3 and mood disorders. Evidence is reviewed that depression may be associated with impaired inhibitory control of GSK3, and mania by hyper-stimulation of GSK3. Taken together, these studies provide substantial support for the hypothesis that inhibition of GSK3 activity is therapeutic for mood disorders. Future research should identify the causes of dysregulated GSK3 in mood disorders and the actions of GSK3 that contribute to these diseases.

Four mood stabilizers commonly induce FEZ1 expression in human astrocytes

OBJECTIVES

  Mood stabilizers influence the morphology, chemotaxis, and survival of neurons, which are considered to be related to the mood-stabilizing effects of these drugs. Although previous studies suggest glial abnormalities in patients with bipolar disorder and an effect of mood stabilizers on certain genes in astrocytes, less is known about the effects of mood stabilizers in astrocytes than in neurons. The present study identifies a common underlying response to mood stabilizers in astrocytes.

METHODS

  Human astrocyte-derived cells (U-87 MG) were treated with the four most commonly used mood stabilizers (lithium, valproic acid, carbamazepine, and lamotrigine) and subjected to microarray gene expression analyses. The most prominently regulated genes were validated by qRT-PCR and western blot analysis. The intercellular localization of one of these regulated genes, fasciculation and elongation protein zeta 1 (FEZ1), was evaluated by immunofluorescence staining.

RESULTS

  The microarray data indicated that FEZ1 was the only gene commonly induced by the four mood stabilizers in human astrocyte-derived cells. An independent experiment confirmed astrocytic FEZ1 induction at both the transcript and protein levels following mood stabilizer treatments. FEZ1 localized to the cytoplasm of transformed and primary astrocytes from the human adult brain.

CONCLUSIONS

  Our data suggest that FEZ1 may play important roles in human astrocytes, and that mood stabilizers might exert their cytoprotective and mood-stabilizing effects by inducing FEZ1 expression in astrocytes.

A systematic, updated review on the antidepressant agomelatine focusing on its melatonergic modulation

Objective:

To present an updated, comprehensive review on clinical and pre-clinical studies on agomelatine.

Method:

A MEDLINE, Psycinfo and Web of Science search (1966-May 2009) was performed using the following keywords: agomelatine, melatonin, S20098, efficacy, safety, adverse effect, pharmacokinetic, pharmacodynamic, major depressive disorder, bipolar disorder, Seasonal Affective Disorder (SAD), Alzheimer, ADHD, Generalized Anxiety Disorder (GAD), Panic Disorder (PD), Obsessive-Compulsive Disorder (OCD), anxiety disorders and mood disorder.

Study collection and data extraction:

All articles in English identified by the data sources were evaluated. Randomized, controlled clinical trials involving humans were prioritized in the review. The physiological bases of melatonergic transmission were also examined to deepen the clinical comprehension of agomelatine’ melatonergic modulation.

Data synthesis:

Agomelatine, a melatonergic analogue drug acting as MT₁/MT₂ agonist and 5-HT_2C antagonist, has been reported to be an effective antidepressant therapy.

Conclusions:

Although a bias in properly assessing the “sleep core” of depression may still exist with current screening instruments, therefore making difficult to compare agomelatine’ efficacy to other antidepressant ones, comparative studies showed agomelatine to be an intriguing option for depression and, potentially, for other therapeutic targets as well.

Epigenetic and inflammatory marker profiles associated with depression in a community-based epidemiologic sample

BACKGROUND

Recent work suggests that epigenetic differences may be associated with psychiatric disorders. Here we investigate, in a community-based sample, whether methylation profiles distinguish between individuals with and without lifetime depression. We also investigate the physiologic consequences that may be associated with these profiles.

METHOD

Using whole blood-derived genomic DNA from a subset of participants in the Detroit Neighborhood Health Study (DNHS), we applied methylation microarrays to assess genome-wide methylation profiles for over 14 000 genes in 33 persons who reported a lifetime history of depression and 67 non-depressed adults. Bioinformatic functional analyses were performed on the genes uniquely methylated and unmethylated in each group, and inflammatory biomarkers [interleukin (IL)-6 and C-reactive protein (CRP)] were measured to investigate the possible functional significance of the methylation profiles observed.

RESULTS

Uniquely unmethylated gene sets distinguished between those with versus without lifetime depression. In particular, some processes (e.g. brain development, tryptophan metabolism) showed patterns suggestive of increased methylation among individuals with depression whereas others (e.g. lipoprotein) showed patterns suggestive of decreased methylation among individuals with depression. IL-6 and CRP levels were elevated among those with lifetime depression and, among those with depression only, IL-6 methylation showed an inverse correlation with circulating IL-6 and CRP.

CONCLUSIONS

Genome-wide methylation profiles distinguish individuals with versus without lifetime depression in a community-based setting, and show coordinated signals with pathophysiological mechanisms previously implicated in the etiology of this disorder. Examining epigenetic mechanisms in concert with other dynamic markers of physiologic functioning should improve our understanding of the neurobiology of depression.

The impact of maternal separation on the number of tyrosine hydroxylase-expressing midbrain neurons during different stages of ontogenesis

Early life stressors have life-long functional and anatomical consequences. Though many neurotransmitters are involved in the functional impact of early life stress, dopamine seems to be important because of its roles in motor control, adaptation to stressful conditions, mood, cognition, attention and reward. Thus, in the present study, we investigated the way that early life stress, in the form of maternal separation (MS), affects the populations of tyrosine hydroxylase-immunoreactive (TH-IR) dopaminergic neurons in rat midbrain structures during ontogenesis. We included in the study the sub-regions of the substantia nigra (SN) and the ventral tegmental area (VTA). In both the control and MS rats, we found that the estimated total number of TH-expressing neurons fluctuated during ontogenesis. Moreover, MS influenced the number of TH-IR cells, especially in the SN pars reticulata (SNr) and VTA. Shortly after the termination of MS, on postnatal day (PND) 15, a decrease in the estimated total number of TH-IR neurons was observed in the SNr and VTA (in both males and females). On PND 35, MS caused a transient increase in the number of TH-IR cells only in the SNr of female rats. On PND 70, MS affected the number of TH-IR neurons in the VTA of females; specifically, an increase in the number of these cells was observed. Additionally, MS did not alter TH-IR cell sizes or the total levels of TH (measured by Western blot analysis) in the SN and VTA for all stages of ontogenesis in both males and females. The results from the study herein indicate that early life stress has enduring effects on the populations of midbrain TH-expressing dopaminergic neurons (especially in female rats), which are critically important for dopamine-regulated brain function throughout ontogenesis.

The hippocampus in major depression: evidence for the convergence of the bench and bedside in psychiatric research?

Major depressive disorder (MDD) has until recently been conceptualized as an episodic disorder associated with 'chemical imbalances' but no permanent brain changes. Evidence has emerged in the past decade that MDD is associated with small hippocampal volumes. This paper reviews the clinical and biological correlates of small hippocampal volumes based on literature searches of PubMed and EMBASE and discusses the ways in which these data force a re-conceptualization of MDD. Preclinical data describe the molecular and cellular effects of chronic stress and antidepressant treatment on the hippocampus, providing plausible mechanisms through which MDD might be associated with small hippocampal volumes. Small hippocampal volumes are associated with poor clinical outcome and may be a mechanism through which MDD appears to be a risk factor for Alzheimer's disease. The pathways through which stress may be linked to MDD, the emergence of chronicity or treatment resistance in MDD and the association between MDD and memory problems may be at least partially understood by dissecting the association with depression and changes in the hippocampus. MDD must be re-conceived as a complex illness, associated with persistent morphological brain changes that are detectable before illness onset and which may be modified by clinical and treatment variables.

Calcium dynamics in dendritic spines: a link to structural plasticity

Calcium signals evoked either by action potential or by synaptic activity play a crucial role for the synaptic plasticity within an individual spine. Because of the small size of spine and the indicators commonly used to measure spine calcium activity, calcium function can be severely disrupted. Therefore, it is very difficult to explain the exact relationship between spine geometry and spine calcium dynamics. Recently, it has been suggested that the medium range of calcium which induces long term potentiation leads to the structural stability stage of spines, while very low or very high amount of calcium leads to the long term depression stage which results in shortening and eventually pruning of spines. Here we propose a physiologically realistic computational model to examine the role of calcium and the mechanisms that govern its regulation in the spine morphology. Calcium enters into spine head through NMDA and AMPA channels and is regulated by internal stores. Contribution of this calcium in the induction of long term potentiation and long term depression is also discussed. Further it has also been predicted that the presence of internal stores depletes the total calcium accumulation in cytosol which is in agreement with the recent experimental and theoretical studies.

Bcl-2 SNP rs956572 associates with disrupted intracellular calcium homeostasis in bipolar I disorder

OBJECTIVES

Disrupted intracellular calcium (Ca(2+) ) homeostasis (ICH) related to mitochondrial and/or endoplasmic reticulum (ER) dysfunction has been implicated in bipolar disorder (BD). The anti-apoptotic protein B-cell CLL/lymphoma 2 (Bcl-2), encoded in a putative BD susceptibility locus, modulates ER-Ca(2+) dynamics. Recently, an intronic single-nucleotide polymorphism (SNP) in the Bcl-2 gene, rs956572, was suggested as a functionally active SNP that influences its messenger RNA (mRNA) and protein level as well as human gray matter volume. We sought to evaluate the impact of this variant on ICH in BD.

METHODS

Basal intracellular Ca(2+) concentrations ([Ca(2+) ](B) ) and rs956572 genotypes were determined in B lymphoblast cell lines (BLCLs) from bipolar I disorder (BD-I) (n=150), bipolar II disorder (BD-II) (n=65), and major depressive disorder (n=30) patients, and from healthy subjects (n=70). Bcl-2 mRNA and protein levels were determined by quantitative reverse transcriptase polymerase chain reaction and immunoblotting, respectively. Functional interactions of rs956572 with ICH were assessed by thapsigargin- and lysophosphatidic acid (LPA)-stimulated Ca(2+) responses.

RESULTS

Although rs956572 variation was not significantly associated with BD, BD-I, or BD-II, BLCL [Ca(2+) ](B) was significantly higher in BD-I G/G patients compared with other genotypes and with healthy subjects. Bcl-2 mRNA and protein levels were lowest in BD-I G/G patients. Compared with A carriers, BD-I patients with G/G variants showed a modest enhancing effect on thapsigargin- and LPA-stimulated Ca(2+) responses.

CONCLUSIONS

These findings support the notion that genetic variation in Bcl-2 affecting its expression impacts ICH in BD. Moreover, we show here for the first time that this interactive effect is diagnostically specific to BD-I.

Spatial inhibition and the visual cortex: a magnetic resonance spectroscopy imaging study

INTRODUCTION

Deficits in processing spatial information have been observed in clinical populations who have abnormalities within the dopamine (DA) system. As psychostimulants such as methamphetamine (MA) are particularly neurotoxic to the dopaminergic system it was of interest to examine the performance of MA-dependent individuals on a task of spatial attention.

METHOD

51 MA-dependent subjects and 22 age-matched non-substance abusing control subjects were tested on a Spatial Stroop attention test. MR Spectroscopy (MRS) imaging data were analyzed from 32 MA abusers and 13 controls.

RESULTS

No group differences in response time or accuracy emerged on the behavioral task with both groups exhibiting equivalent slowing when the word meaning and the spatial location of the word were in conflict. MRS imaging data from the MA abusers revealed a strong inverse correlation between NAA/Cr ratios in the Primary Visual Cortex (PVC) and spatial interference (p=0.0001). Moderate inverse correlations were also seen in the Anterior Cingulate Cortex (ACC) (p=0.02). No significant correlations were observed in the controls, perhaps due to the small sample of imaging data available (n=13).

DISCUSSION

The strong correlation between spatial conflict suppression and NAA/Cr levels within the PVC in the MA-dependent individuals suggests that preserved neuronal integrity within the PVC of stimulant abusers may modulate cognitive mechanisms that process implicit spatial information.

MicroRNA-134 plasma levels before and after treatment for bipolar mania

Studies have previously documented that microRNAs (miRNAs), with their key roles in regulating both synaptic plasticity and brain development, are candidate genetic contributors to the etiopathology of bipolar disorder (BD). Moreover, miRNA identified as targets for the actions of chronic lithium and VPA are known to play diverse and intriguing roles in brain function. In particular, the brain specific miR-134 has recently been identified as a potential regulator of dendritic spine volume and synapse formation. Recently, circulating miRNAs have been reported as promising biomarkers for various pathologic conditions. We assessed the hypothesis that miRNA-134 may be present and detectable in circulating blood, and that miRNA-134 may serve as a biomarker of mania episodes in BD. In the present study, we recruited 21 bipolar I, manic (DSM-IV) patients and controls matched by sex and age for quantification of miR-134 level in plasma using real-time RT-PCR method. We found that: Plasma miR-134 levels in drug-free, 2-week medicated, and 4-week medicated bipolar mania patients were significantly decreased when compared with controls, and the level was increased on following medication. Decreased circulating miR-134 level both in drug-free and medicated patients did presented negative correlation with the clinical scales. Overall, these results suggest that the decreased plasma miR-134 levels may be directly associated with the pathophysiology and severity of manic symptoms in BD. Plasma miRNA-134 in BD may be considered as a potential peripheral marker that can respond to acute manic episodes and associate with effective mood stabilizers treatment.

Reduced right posterior hippocampal volume in women with recurrent familial pure depressive disorder

Volumetric changes in mood-relevant distributed limbic/paralimbic structures have been reported in the recent literature on the course of mood disorders. Patients with unipolar and bipolar disorders have been found to have smaller hippocampal and anterior cingulate volumes. We examined hippocampal, amygdalar and anterior cingulate cortex (ACC) volumes in female patients with recurrent familial pure depressive disorder (rFPDD). We used semi-automated software for magnetic resonance imaging (MRI) to measure the volumes of the hippocampus, amygdala, ACC and subgenual prefrontal cortex (SGPFC) in 15 female patients with familial recurrent major depression (MD) and 15 healthy female subjects. Analysis of covariance, with whole brain volume as covariate, was used to compare volumetric measurements in the two groups. Volumes of the right hippocampal body and tail were significantly smaller in female patients with familial depressive disorder than in healthy subjects. Our data provide evidence of structural lateralized hippocampal body and tail abnormalities in women with familial history and recurrent episodes of depression. Although global reduction of hippocampal volume has been widely reported, data on lateralized regional reductions in familial recurrent depression had not been previously reported. Reduced volume of the right posterior hippocampus could be a structural endophenotype for recurrent depressive disorders in women.

Effects of erythropoietin on depressive symptoms and neurocognitive deficits in depression and bipolar disorder

Background

Depression and bipolar disorder are associated with reduced neural plasticity and deficits in memory, attention and executive function. Drug treatments for these affective disorders have insufficient clinical effects in a large group and fail to reverse cognitive deficits. There is thus a need for more effective treatments which aid cognitive function. Erythropoietin (Epo) is involved in neuroplasticity and is a candidate for future treatment of affective disorders. The investigators have demonstrated that a single dose of Epo improves cognitive function and reduces neurocognitive processing of negative emotional information in healthy and depressed individuals similar to effects seen with conventional antidepressants. The current study adds to the previous findings by investigating whether repeated Epo administration has antidepressant effects in patients with treatment resistant depression and reverses cognitive impairments in these patients and in patients with bipolar disorder in remission.

Methods/design

The trial has a double-blind, placebo-controlled, parallel-group design. 40 patients with treatment-resistant major depression and 40 patients with bipolar disorder in remission are recruited and randomised to receive weekly infusions of Epo (Eprex; 40,000 IU) or saline (NaCl 0.9%) for 8 weeks. Randomisation is stratified for age and gender. The primary outcome parameters for the two studies are: depression severity measured with the Hamilton Depression Rating Scale 17 items (HDRS-17) [1] in study 1 and, in study 2, verbal memory measured with the Rey Auditory Verbal Learning Test (RAVLT) [2,3]. With inclusion of 40 patients in each study we obtain 86% power to detect clinically relevant differences between intervention and placebo groups on these primary outcomes.

Trial registration

The trial is approved by the Local Ethics Committee: H-C-2008-092, Danish Medicines Agency: 2612-4020, EudraCT: 2008-04857-14, Danish Data Agency: 2008-41-2711 and ClinicalTrials.gov: NCT 00916552.

Pathways underlying neuroprogression in bipolar disorder: focus on inflammation, oxidative stress and neurotrophic factors

There is now strong evidence of progressive neuropathological processes in bipolar disorder (BD). On this basis, the current understanding of the neurobiology of BD has shifted from an initial focus on monoamines, subsequently including evidence of changes in intracellular second messenger systems and more recently to, incorporating changes in inflammatory cytokines, corticosteroids, neurotrophins, mitochondrial energy generation, oxidative stress and neurogenesis into a more comprehensive model capable of explaining some of the clinical features of BD. These features include progressive shortening of the inter-episode interval with each recurrence, occurring in consort with reduced probability of treatment response as the illness progresses. To this end, emerging data shows that these biomarkers may differ between early and late stages of BD in parallel with stage-related structural and neurocognitive alterations. This understanding facilitates identification of rational therapeutic targets, and the development of novel treatment classes. Additionally, these pathways provide a cogent explanation for the efficacy of seemingly diverse therapies used in BD, that appear to share common effects on oxidative, inflammatory and neurotrophic pathways.

13-Cis-retinoic acid decreases hypothalamic cell number in vitro

13-Cis-retinoic acid (13-cis-RA) causes depression-related behavior in mice. Hypothalamic dysregulation has been implicated in clinical depression. In fact, apoptosis of hypothalamic neurons may lead to depression after myocardial infarction. Our objective was to determine if 13-cis-RA affects cultured hypothalamic cell number. Treatment of GT1-7 hypothalamic cells with 10μM 13-cis-RA for 48h decreased cell growth to 45.6±13% of control. To determine if this decrease in cell number was due to 13-cis-RA acting as an oxidant, cells were treated with 13-cis-RA and ascorbic acid or butylated hydroxyanisole (BHA) for 24 or 48h. Neither antioxidant alleviated the inhibitory affects of 13-cis-RA. In addition, 13-cis-RA treatment did not increase superoxide anion production, indicating 13-cis-RA was not acting as an oxidant. To determine if 13-cis-RA was acting via retinoic acid receptors (RARs) to decrease cell number, GT1-7 cells were treated with 13-cis-RA and the RAR pan-antagonist, AGN 193109. Treatment with the RAR-antagonist blocked the ability of 13-cis-RA to decrease cell number, indicating this phenomenon was a RAR-independent mechanism. We hypothesize that the ability of 13-cis-RA to decrease hypothalamic cell number may contribute to the increased depression-related behaviors observed in mice.

Pharmacogenomics of mood stabilizers in the treatment of bipolar disorder

Bipolar disorder (BD) is a chronic and often severe psychiatric illness characterized by manic and depressive episodes. Among the most effective treatments, mood stabilizers represent the keystone in acute mania, depression, and maintenance treatment of BD. However, treatment response is a highly heterogeneous trait, thus emphasizing the need for a structured informational framework of phenotypic and genetic predictors. In this paper, we present the current state of pharmacogenomic research on long-term treatment in BD, specifically focusing on mood stabilizers. While the results provided so far support the key role of genetic factors in modulating the response phenotype, strong evidence for genetic predictors is still lacking. In order to facilitate implementation of pharmacogenomics into clinical settings (i.e., the creation of personalized therapy), further research efforts are needed.

The genetics of mood disorders

Studying the genetics of mood disorders has never been more exciting. We have moved rapidly from establishing the genetic basis of depression to asking questions about how genes are expressed. This has been made possible by the capacity to collect and sequence DNA for large samples cheaply. But "multidisciplinary" approaches investigating interrelationships between risk factors have also been increasingly adopted, encouraging collaborations between those studying genes and those studying the brain, cognition, and/or the social environment. In this review, we first describe findings from quantitative and molecular studies investigating the genetic basis of depression. Second, we present overviews of three hot topics of genetic research: gene-environment interplay, which considers how genetic factors shape exposure and responses toward the social environment; endophenotypic research, which identifies neurophysiological and psychological mediators of genetic risk; and epigenetics, which explain how early environments can foster changes in gene expression, altering subsequent emotional development.

Early life stressors and genetic influences on the development of bipolar disorder: the roles of childhood abuse and brain-derived neurotrophic factor

OBJECTIVES

Although there is increasing research exploring the psychosocial influences and biological underpinnings of bipolar disorder, relatively few studies have specifically examined the interplay between these factors in the development of this illness. Social-biological models within a developmental psychopathology perspective are necessary to advance our understanding of the processes involved in the onset and course of bipolar disorder. This article presents a review of the empirical literature linking childhood abuse to bipolar disorder, the research to date on the possible role of brain-derived neurotrophic factor (BDNF) in the development of this disorder, followed by a discussion of how childhood abuse may interact with BDNF.

METHODS

A literature search was conducted using Psycinfo to identify relevant articles on childhood abuse, BDNF, and bipolar disorder.

RESULTS

The extant research implicates both childhood abuse and BDNF in the etiology of bipolar disorder. Specifically, there is growing evidence associating early abuse to the development of bipolar disorder. Similarly, the BDNF Val66 allele has been linked with increased susceptibility to bipolar disorder. Based on existing research, a genetic diathesis-transactional stress model is proposed incorporating childhood abuse and the BDNF gene in the pathogenesis of bipolar disorder.

CONCLUSIONS

Although there is some support for this model, the relatively modest amount of relevant literature highlights the need for further research. An integrative theoretical framework including both social and biological processes in bipolar disorder is important for the development of effective prevention and treatment strategies for this disorder.

Stable isotope-resolved metabolomic analysis of lithium effects on glial-neuronal metabolism and interactions

Despite the long-established therapeutic efficacy of lithium in the treatment of bipolar disorder (BPD), its molecular mechanism of action remains elusive. Newly developed stable isotope-resolved metabolomics (SIRM) is a powerful approach that can be used to elucidate systematically how lithium impacts glial and neuronal metabolic pathways and activities, leading ultimately to deciphering its molecular mechanism of action. The effect of lithium on the metabolism of three different (13)C-labeled precursors ([U-(13)C]-glucose, (13)C-3-lactate or (13)C-2,3-alanine) was analyzed in cultured rat astrocytes and neurons by nuclear magnetic resonance (NMR) spectroscopy and gas chromatography mass spectrometry (GC-MS). Using [U-(13)C]-glucose, lithium was shown to enhance glycolytic activity and part of the Krebs cycle activity in both astrocytes and neurons, particularly the anaplerotic pyruvate carboxylation (PC). The PC pathway was previously thought to be active in astrocytes but absent in neurons. Lithium also stimulated the extracellular release of (13)C labeled-lactate, -alanine (Ala), -citrate, and -glutamine (Gln) by astrocytes. Interrogation of neuronal pathways using (13)C-3-lactate or (13)C-2,3-Ala as tracers indicated a high capacity of neurons to utilize lactate and Ala in the Krebs cycle, particularly in the production of labeled Asp and Glu via PC and normal cycle activity. Prolonged lithium treatment enhanced lactate metabolism via PC but inhibited lactate oxidation via the normal Krebs cycle in neurons. Such lithium modulation of glycolytic, PC and Krebs cycle activity in astrocytes and neurons as well as release of fuel substrates by astrocytes should help replenish Krebs cycle substrates for Glu synthesis while meeting neuronal demands for energy. Further investigations into the molecular regulation of these metabolic traits should provide new insights into the pathophysiology of mood disorders and early diagnostic markers, as well as new target(s) for effective therapies.

Erythropoietin modulates neural and cognitive processing of emotional information in biomarker models of antidepressant drug action in depressed patients

OBJECTIVE

Erythropoietin (Epo) has neuroprotective and neurotrophic effects, and may be a novel therapeutic agent in the treatment of psychiatric disorders. We have demonstrated antidepressant-like effects of Epo on the neural and cognitive processing of facial expressions in healthy volunteers. The current study investigates the effects of Epo on the neural and cognitive response to emotional facial expressions in depressed patients.

METHOD

Nineteen acutely depressed patients were randomized to receive Epo (40,000 IU) or saline intravenously in a double-blind, parallel-group design. On day 3, we assessed neuronal responses to fearful and happy faces using functional magnetic resonance imaging and measured facial expression recognition after the scan.

RESULTS

Epo reduced neural response to fearful vs. happy faces in the amygdala and hippocampus, and to fearful faces vs. baseline in superior temporal and occipitoparietal regions 3 days after administration in acutely depressed patients. This was accompanied by a specific reduction in the recognition of fear in Epo-treated patients after the scan similar to the effects on face recognition seen with antidepressant drug treatment.

CONCLUSIONS

The present findings are similar to the effects of conventional antidepressants in acutely depressed patients and opposite to hypervigilance to negative facial expressions in depression. This highlights a potential antidepressant mechanism and warrants further investigation of Epo as a new candidate compound for treatment of depression.

Mood disorders are glial disorders: evidence from in vivo studies

It has recently been suggested that mood disorders can be characterized by glial pathology as indicated by histopathological postmortem findings. Here, we review studies investigating the glial marker S100B in serum of patients with mood disorders. This protein might act as a growth and differentiation factor. It is located in, and may actively be released by, astro- and oligodendrocytes. Studies consistently show that S100B is elevated in mood disorders; more strongly in major depressive than bipolar disorder. Successful antidepressive treatment reduces S100B in major depression whereas there is no evidence of treatment effects in mania. In contrast to the glial marker S100B, the neuronal marker protein neuron-specific enolase is unaltered. By indicating glial alterations without neuronal changes, serum S100B studies confirm specific glial pathology in mood disorders in vivo. S100B can be regarded as a potential diagnostic biomarker for mood disorders and as a biomarker for successful antidepressive treatment.

Increased plasma levels of brain-derived neurotrophic factor in patients with long-term bipolar disorder

Recent data indicate that neurotrophins may play a role in the physiopathology of bipolar disorder (BD) and may be useful as biomarkers of the disease. The aim of this study was to evaluate the plasma concentrations of brain-derived neurotrophic factor (BDNF) in BD patients, and to correlate their levels with clinical parameters. BDNF was measured in plasma from 53 BD type I subjects (34 during mania and 19 during euthymia) and 38 healthy controls by enzyme-linked immuno-sorbent assay (ELISA). Patients were assessed by a structured clinical interview (Mini-plus), Young mania and Hamilton depression rating scales. Plasma BDNF levels were significantly increased in patients with mania (P</=0.001) and euthymia (P</=0.001) when compared with controls, but did not correlate with any clinical parameters. BDNF concentration was higher in BD patients with 10 or more years of disease. BDNF plasma levels were increased in BD patients, mainly in those with a longer course of disease. In line with previous studies, it is conceivable that BDNF may play a role in the pathophysiology of BD.

Correlation analysis between genome-wide expression profiles and cytoarchitectural abnormalities in the prefrontal cortex of psychiatric disorders

Cytoarchitectural abnormalities have been described in the prefrontal cortex of subjects with schizophrenia, bipolar disorder and depression. However, little is known about the gene expression profiles associated with these abnormalities. Genome-wide expression profiling technology provides an unbiased approach to identifying candidate genes and biological processes that may be associated with complex biological traits such as cytoarchitecture. In this study, we explored expression profiles associated with the abnormalities by using publicly available microarray metadata and cytoarchitectural data from post-mortem samples of the frontal cortex from 54 subjects (schizophrenia, n=14; bipolar disorder, n=13; depression, n=12 and controls n=15). Correlation analysis between genome-wide expression levels and cytoarchitectural traits revealed that 818 genes were significantly correlated with a decrease in the number of perineuronal oligodendrocytes across all subjects. A total of 600 genes were significantly correlated with a decrease in density of calbindin-positive interneurons across all subjects. Multiple biological processes including cellular metabolism, central nervous system development, cell motility and programmed cell death were significantly overrepresented in both correlated gene lists. These findings may provide novel insights into the molecular mechanisms that underlie the cytoarchitectural abnormalities of perineuronal oligodendrocytes and calbindin-containing GABAergic interneurons in the prefrontal cortex of the major psychiatric disorders.

Temporal lobe grey matter volume in schizophrenia is associated with a genetic polymorphism influencing glycogen synthase kinase 3-β activity

At the crossroad of multiple pathways regulating trophism and metabolism, glycogen synthase kinase (GSK)3 is considered a key factor in influencing the susceptibility of neurons to harmful stimuli (neuronal resilience) and is a target for several psychiatric drugs that directly inhibit it or increase its inhibitory phosphorylation. Inhibition of GSK3 prevents apoptosis and could protect against the neuropathological processes associated with psychiatric disorders. A GSK3-beta promoter single-nucleotide polymorphism (rs334558) influences transcriptional strength, and the less active form was associated with less detrimental clinical features of mood disorders. Here we studied the effect of rs334558 on grey matter volumes (voxel-based morphometry) of 57 patients affected by chronic schizophrenia. Carriers of the less active C allele variant showed significantly higher brain volumes in an area encompassing posterior regions of right middle and superior temporal gyrus, within the boundaries of Brodmann area 21. The temporal lobe is the brain parenchymal region with the most consistently documented morphometric abnormalities in schizophrenia, and neuropathological processes in these regions develop soon at the beginning of the illness. These results support the interest for GSK3-beta as a factor affecting neuropathology in major behavioural disorders, such as schizophrenia, and thus as a possible target for treatment.

Chronic creatine supplementation alters depression-like behavior in rodents in a sex-dependent manner

Impairments in bioenergetic function, cellular resiliency, and structural plasticity are associated with the pathogenesis of mood disorders. Preliminary evidence suggests that creatine, an ergogenic compound known to promote cell survival and influence the production and usage of energy in the brain, can improve mood in treatment-resistant patients. This study examined the effects of chronic creatine supplementation using the forced swim test (FST), an animal model selectively sensitive to antidepressants with clinical efficacy in human beings. Thirty male (experiment 1) and 36 female (experiment 2) Sprague-Dawley rats were maintained on either chow alone or chow blended with either 2% w/w creatine monohydrate or 4% w/w creatine monohydrate for 5 weeks before the FST. Open field exploration and wire suspension tests were used to rule out general psychostimulant effects. Male rats maintained on 4% creatine displayed increased immobility in the FST as compared with controls with no differences by diet in the open field test, whereas female rats maintained on 4% creatine displayed decreased immobility in the FST and less anxiety in the open field test compared with controls. Open field and wire suspension tests confirmed that creatine supplementation did not produce differences in physical ability or motor function. The present findings suggest that creatine supplementation alters depression-like behavior in the FST in a sex-dependent manner in rodents, with female rats displaying an antidepressant-like response. Although the mechanisms of action are unclear, sex differences in creatine metabolism and the hormonal milieu are likely involved.

BDNF gene polymorphism (Val66Met) predicts amygdala and anterior hippocampus responses to emotional faces in anxious and depressed adolescents

A polymorphism of the human Brain Derived Neurotrophic Factor (BDNF) gene that produces a valine-to-methionine substitution at codon 66 (Val66Met) is linked to adult anxiety and mood disorders, possibly through effects on brain circuitry function. Associations between BDNF gene variants and brain activity have not been explored in anxious and depressed adolescents. The current study investigated the association between BDNF genotype and amygdala-hippocampal responses to emotional stimuli in adolescents with anxiety disorders and/or major depressive disorder (MDD) and in healthy adolescents. Twenty-seven unmedicated patients with acutely-impairing current anxiety disorders and/or MDD and 31 healthy adolescents, matched on age, gender and IQ, rated their fear of fearful, angry, neutral and happy facial expressions during collection of fMRI data on the amygdala and hippocampus. Left and right amygdala and hippocampal responses were analyzed using repeated-measures analyses of variance models, with diagnosis (patients, healthy) and genotype (Met-carriers, Val/Val homozygotes) as between-group factors and facial expression (fearful, angry, neutral, happy) as a within-subject factor. Significant effects of diagnosis and diagnosis-by-genotype interactions (F's>4, p's<0.05) characterized activations in amygdala and anterior hippocampal regions. Greater activations in patients than healthy adolescents were found. Critically, these hyperactivations were modulated by BDNF genotype: Met-carriers showed greater neural responses of emotional faces than Val/Val homozygotes in patients only. These data are first to demonstrate the contribution of BDNF gene variants to the neural correlates of adolescent anxiety and depression. Early "gene-brain" linkages may lay the foundation for longer-term patterns of neural dysfunction in affective disorders.

Chronic NMDA administration to rats increases brain pro-apoptotic factors while decreasing anti-Apoptotic factors and causes cell death

BACKGROUND

Chronic N-Methyl-d-aspartate (NMDA) administration to rats is reported to increase arachidonic acid signaling and upregulate neuroinflammatory markers in rat brain. These changes may damage brain cells. In this study, we determined if chronic NMDA administration (25 mg/kg i.p., 21 days) to rats would alter expression of pro- and anti-apoptotic factors in frontal cortex, compared with vehicle control.

RESULTS

Using real time RT-PCR and Western blotting, chronic NMDA administration was shown to decrease mRNA and protein levels of anti-apoptotic markers Bcl-2 and BDNF, and of their transcription factor phospho-CREB in the cortex. Expression of pro-apoptotic Bax, Bad, and 14-3-3zeta was increased, as well as Fluoro-Jade B (FJB) staining, a marker of neuronal loss.

CONCLUSION

This alteration in the balance between pro- and anti-apoptotic factors by chronic NMDA receptor activation in this animal model may contribute to neuronal loss, and further suggests that the model can be used to examine multiple processes involved in excitotoxicity.

Antiapoptotic and neurotrophic effects of antidepressants: a review of clinical and experimental studies

Recent studies have strengthened the role of the abnormalities in neurotrophic pathways in the pathophysiology of depression. It has been shown that the depletion of growth factors, particularly brain-derived neurotrophic factor, may result in depression-like behavior in animals and may induce cellular changes that are reminiscent of those observed in depressed patients. Some authors even suggested that increased neuronal cell loss may contribute to the pathogenesis of depression. Hence, appreciable interest has been focused on the trophic and antiapoptotic effects of antidepressant drugs. In this paper, we put emphasis on the contribution of hippocampal atrophy, increased cell death and alterations in trophic factors to the pathogenesis of depression and their relationship to the potential of antidepressants to reverse these changes by modulating trophic factor cascades and preventing apoptosis. First, evidences for increased hippocampal atrophy and cell death in depression are discussed, followed by a review of selected studies of special interest that concern antiapoptotic action of antidepressant drugs. Next, depression-related neurotrophic abnormalities and their reversal by antidepressants are depicted. Finally, relationships among neurotrophins, antiapoptotic proteins and antioxidant enzymes in the pathology and treatment of depression are pointed out.

Effects of the brain-derived neurotrophic growth factor val66met variation on hippocampus morphology in bipolar disorder

Histological and behavioral research in bipolar disorder (BD) implicates structural abnormalities in the hippocampus. Brain-derived neurotrophic growth factor (BDNF) protein is associated with hippocampal development and plasticity, and in mood disorder pathophysiology. We tested the hypotheses that both the BDNF val66met polymorphism and BD diagnosis are associated with decreased hippocampus volume, and that individuals with BD who carry the met allele have the smallest hippocampus volumes compared to individuals without BD and val/val homozygotes. We further explored localization of morphological differences within hippocampus in BD associated with the met allele. Twenty individuals with BD and 18 healthy comparison (HC) subjects participated in high-resolution magnetic resonance imaging scans from which hippocampus volumes were defined and measured. We used linear mixed model analysis to study effects of diagnosis and BDNF genotype on hippocampus volumes. We then employed three-dimensional mapping to localize areas of change within the hippocampus associated with the BDNF met allele in BD. We found that hippocampus volumes were significantly smaller in BD compared to HC subjects, and presence of the BDNF met allele was associated with smaller hippocampus volume in both diagnostic groups. The BD subgroup who carried the BDNF met allele had the smallest hippocampus volumes, and three-dimensional mapping identified these decreases as most prominent in left anterior hippocampus. These results support effects of BD diagnosis and BDNF genotype on hippocampus structure and suggest a genetic subgroup within BD who may be most vulnerable to deficits in hippocampus and may most benefit from interventions that influence BDNF-mediated signaling.

Serum markers support disease-specific glial pathology in major depression

BACKGROUND

Recently, it was shown by histopathological studies that mood disorders are characterized by disease-specific glial pathology.

METHODS

To validate this hypothesis in vivo we measured weekly and simultaneously serum levels of the neuronal marker neuron-specific enolase and S100B, a protein expressed in astro- and oligodendroglia in the human brain, in 10 patients with major depressive disorder and 10 age- and gender-matched control subjects. Furthermore, we conducted a systematic, quantitative meta-analysis of all published studies on S100B involving 193 patients suffering from mood disorders and 132 healthy control subjects by calculating effect sizes.

RESULTS

S100B was elevated at admission and discharge in our patients with major depression compared with control subjects, whereas there were no significant differences for neuron-specific enolase. During treatment S100B decreased slightly, although this effect was not significant. It had no significant impact on neuron-specific enolase. The meta-analysis revealed that serum levels of S100B are consistently elevated in mood disorders during acute major depressive or manic episodes. Additionally, it demonstrated that serum S100B decreases during antidepressive treatment reliably if clinical improvement is sufficient.

LIMITATIONS

As the study measured only serum S100B, future (cell culture) studies have to elucidate molecular mechanisms of this protein in mood disorders. Moreover, results have to be replicated in a larger patient group.

CONCLUSIONS

S100B may represent a biomarker for mood disorders, particularly major depression, and their treatment. Together with unaltered levels of neuron-specific enolase, our results support in vivo the histopathologically generated hypothesis of disease-specific glial pathology in mood disorders.

Serum S100B Levels and Major Depressive Disorder: Its Characteristics and Role in Antidepressant Response

OBJECTIVE

S100B is a neurotrophic factor that is involved in neuroplasticity. Neuroplasticity is disrupted in depression; however, treatment with antidepressants can restore neuroplasticity. S100B has previously been used as a biological marker for neuropathology and neuroplasticity; therefore, in this study, we compared serum S100B levels in depressive patients to those of normal controls. In addition, we compared the serum S100B levels of antidepressant responders to those of nonresponders.

METHODS

Thirty five normal controls and 59 depressive patients were enrolled in this study. Depressive patients entered a 6 week clinical trial that included treatment with antidepressants. The serum S100B levels and clinical assessments, which included Hamilton depression rating scores, were measured at baseline and after 6 weeks of treatment with antidepressants. The difference in the serum S100B levels between depressive patients and normal controls and between antidepressant responders and nonresponders was then compared.

RESULTS

There were no significant differences in the serum S100B levels of normal controls and depressive patients. In addition, 30 of the depressive patients responded to antidepressant treatment while 29 did not. Finally, the responders had significantly higher baseline serum S100B levels than the nonresponders.

CONCLUSION

The results of this study suggest that the baseline serum S100B level is associated with the subsequent response to antidepressants. In addition, the high baseline serum S100B level that was observed in depressive patients may enhance neuroplasticity, which results in a favorable therapeutic response to antidepressants.

Early intervention in bipolar disorder, part II: therapeutics

Recent evidence has shown that early pharmacological and psychosocial treatment dramatically ameliorates poor prognosis and outcome for individuals with psychotic disorders, reducing conversion rates to full-blown illness and decreasing symptom severity. In a companion paper, we discussed methodological issues pertaining to early intervention in bipolar disorder (BPD), reviewed clinical studies that focus on high-risk subjects as well as first-episode patients, and reviewed findings from brain imaging studies in the offspring of individuals with BPD as well as in first-episode patients. In this paper, we discuss how drugs that modulate cellular and neural plasticity cascades are likely to benefit patients in the very early stages of BPD, because they target some of the core pathophysiological mechanisms of this devastating illness. Cellular and molecular mechanisms of action of agents with neurotrophic and neuroplastic properties are discussed, with a particular emphasis on lithium and valproate. We also discuss their potential use as early intervention strategies for improving symptoms and functioning in patients in the earliest stages of BPD, as well as high-risk individuals.

Stargazin involvement with bipolar disorder and response to lithium treatment

OBJECTIVES

Multiple reports have implicated chromosomal region 22q13.1 in both schizophrenia and bipolar disorder. The calcium channel gamma-2 subunit gene (cacng2, Stargazin) located on 22q13.1 was recently reported to be associated with schizophrenia. We aimed to examine the expression levels of Stargazin in post-mortem brain samples of patients with schizophrenia, patients with bipolar disorder (BPD) and healthy controls, test for genetic association between Stargazin and these disorders and test for genetic association between Stargazin and response to lithium treatment.

METHODS

Expression analysis was carried out by quantitative reverse transcription-PCR in RNA samples from dorsolateral prefrontal cortices of patients with schizophrenia, patients with BPD and controls (n=35 each). Twelve single nucleotide polymorphisms encompassing Stargazin were genotyped in DNA samples from two cohorts, 'Aberdeen' and 'Cagliari' (n=410, 170, respectively). Patients were treated with lithium and divided into groups according to their response.

RESULTS

A 1.6-fold overexpression of Stargazin was observed in patients with BPD (P=0.000036). No difference in expression was observed in patients with schizophrenia. None of the 12 genotyped single nucleotide polymorphisms were associated with BPD, but three of them were significantly associated with lithium response: one in both cohorts (rs2284017) and two (rs2284018, rs5750285) each in a different cohort. Haplotype analysis revealed significant 'response-protective' and 'response-inhibitive' haplotypes in both cohorts.

CONCLUSION

Our findings suggest that Stargazin dysregulation may be involved with the pathophysiology of BPD, but not with that of schizophrenia, and that Stargazin polymorphisms may play a role in the response to lithium treatment.

Effects of repeated citalopram treatments on chronic mild stress-induced growth associated protein-43 mRNA expression in rat hippocampus

Although growth associated protein-43 (GAP-43) is known to play a significant role in the regulation of axonal growth and the formation of new neuronal connections in the hippocampus, there is only a few studies on the effects of acute stress on GAP-43 mRNA expression in the hippocampus. Moreover, the effects of repeated citalopram treatment on chronic mild stress (CMS)-induced changes in GAP-43 mRNA expression in the hippocampus have not been explored before. To explore this question, male rats were exposed to acute immobilization stress or CMS. Also, citalopram was given prior to stress everyday during CMS procedures. Acute immobilization stress significantly increased GAP-43 mRNA expression in all subfields of the hippocampus, while CMS significantly decreased GAP-43 mRNA expression in the dentate granule cell layer (GCL). Repeated citalopram treatment decreased GAP-43 mRNA expression in the GCL compared with unstressed controls, but this decrease was not further potentiated by CMS exposure. Similar decreases in GAP-43 mRNA expression were observed in CA1, CA3 and CA4 areas of the hippocampus only after repeated citalopram treatment in CMS-exposed rats. This result indicates that GAP-43 mRNA expression in the hippocampus may differently respond to acute and chronic stress, and that repeated citalopram treatment does not change CMS-induced decreases in GAP-43 mRNA expression in the GCL.

Targeting the glutamatergic system to develop novel, improved therapeutics for mood disorders

Mood disorders are common, chronic, recurrent mental illnesses that affect the lives of millions of individuals worldwide. To date, the monoaminergic systems (serotonergic, noradrenergic and dopaminergic) in the brain have received the greatest attention in neurobiological studies of mood disorders, and most therapeutics target these systems. However, there is growing evidence that the glutamatergic system is central to the neurobiology and treatment of these disorders. Here, we review data supporting the involvement of the glutamatergic system in mood-disorder pathophysiology as well as the efficacy of glutamatergic agents in mood disorders. We also discuss exciting new prospects for the development of improved therapeutics for these devastating disorders.

VGF, a new player in antidepressant action?

Recent studies have identified adaptations of intracellular signaling pathways and target genes that could contribute or modulate the action of antidepressant drugs, as well as exercise-mediated antidepressant responses. Understanding these adaptations, particularly those changes that are common to diverse antidepressant treatments, is important for the development of more potent and specific treatments of depression. There is growing evidence that growth factors may be important mediators of antidepressant responses. Now, VGF (not an acronym), a neuropeptide that has previously been shown to be involved in maintaining organismal energy balance, as well as in mediating hippocampal synaptic plasticity, may be involved in mediating antidepressant responses. These studies use in vivo approaches to link VGF to the antidepressant-like behavioral effects produced by antidepressant drugs and exercise.

BDNF level in the rat prefrontal cortex increases following chronic but not acute treatment with duloxetine, a dual acting inhibitor of noradrenaline and serotonin re-uptake

AIMS

Brain-Derived Neurotrophic Factor (BDNF) has a central role in neuronal survival, differentiation, and plasticity. The brain level of BDNF is changed by several mood stabilizers and antidepressant drugs acting on neurotransmitters such as noradrenaline and serotonin. We investigated the effects of acute and chronic treatment with Duloxetine, a new drug blocking the re-uptake of serotonin and noradrenaline (SNRI), on BDNF level in the prefrontal cortex, cerebrospinal fluid, plasma, and serum.

METHODS

Wistar male rats were treated with acute (single treatment) and chronic oral administration (14 days) of different concentrations of Duloxetine (10, 30, and 100 mg/kg/day). At the end of the treatment periods, samples of blood, CSF and the prefrontal cortex were collected. BDNF levels were measured by ELISA. Levels of mature and precursor form of BDNF were measured by Western blot analysis.

RESULTS

Animals treated with the Duloxetine at all concentrations and examined after 1 and 24 h (single treatment) did not reveal a significant change in the total BDNF level. In animals treated for 14 days with Duloxetine at 30 and 100 mg/kg, the total BDNF level increased significantly in the prefrontal cortex and CSF, but not in the plasma and serum. Using a specific antibody and Western blot we showed that the mature, but not the precursor, form of BDNF was significantly increased in the prefrontal cortex of rats treated for 14 days with Duloxetine at 30 mg/kg/day.

CONCLUSIONS

Our results show a major finding that repeated, but not single, Duloxetine treatment increases the level of BDNF in the prefrontal cortex.

Selective loss of brain-derived neurotrophic factor in the dentate gyrus attenuates antidepressant efficacy

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays an important role in neural plasticity in the adult nervous system and has been suggested as a target gene for antidepressant treatment. The neurotrophic hypothesis of depression suggests that loss of BDNF from the hippocampus contributes to an increased vulnerability for depression, whereas upregulation of BDNF in the hippocampus is suggested to mediate antidepressant efficacy.

METHODS

We have used a viral-mediated gene transfer approach to assess the role of BDNF in subregions of the hippocampus in a broad array of behavioral paradigms, including depression-like behavior and antidepressant responses. We have combined the adeno-associated virus (AAV) with the Cre/loxP site-specific recombination system to induce the knockout of BDNF selectively in either the CA1 or dentate gyrus (DG) subregions of the hippocampus.

RESULTS

We show that the loss of BDNF in either the CA1 or the DG of the hippocampus does not alter locomotor activity, anxiety-like behavior, fear conditioning, or depression-related behaviors. However, the selective loss of BDNF in the DG but not the CA1 region attenuates the actions of desipramine and citalopram in the forced swim test.

CONCLUSIONS

These data suggest that the loss of hippocampal BDNF per se is not sufficient to mediate depression-like behavior. However, these results support the view that BDNF in the DG might be essential in mediating the therapeutic effect of antidepressants.

Phenomic, convergent functional genomic, and biomarker studies in a stress-reactive genetic animal model of bipolar disorder and co-morbid alcoholism

We had previously identified the clock gene D-box binding protein (Dbp) as a potential candidate gene for bipolar disorder and for alcoholism, using a Convergent Functional Genomics (CFG) approach. Here we report that mice with a homozygous deletion of DBP have lower locomotor activity, blunted responses to stimulants, and gain less weight over time. In response to a chronic stress paradigm, these mice exhibit a diametric switch in these phenotypes. DBP knockout mice are also activated by sleep deprivation, similar to bipolar patients, and that activation is prevented by treatment with the mood stabilizer drug valproate. Moreover, these mice show increased alcohol intake following exposure to stress. Microarray studies of brain and blood reveal a pattern of gene expression changes that may explain the observed phenotypes. CFG analysis of the gene expression changes identified a series of novel candidate genes and blood biomarkers for bipolar disorder, alcoholism, and stress reactivity.

A systematic review of existing data on long-term lithium therapy: neuroprotective or neurotoxic?

Lithium is an efficacious agent for the treatment of bipolar disorder, but it is unclear to what extent its long-term use may result in neuroprotective or toxic consequences. Medline was searched with the combination of the word 'Lithium' plus key words that referred to every possible effect on the central nervous system. The papers were further classified into those supporting a neuroprotective effect, those in favour of a neurotoxic effect and those that were neutral. The papers were classified into research in humans, animal and in-vitro research, case reports, and review/opinion articles. Finally, the Natural Standard evidence-based validated grading rationale was used to validate the data. The Medline search returned 970 papers up to February 2006. Inspection of the abstracts supplied 214 papers for further reviewing. Eighty-nine papers supported the neuroprotective effect (6 human research, 58 animal/in vitro, 0 case reports, 25 review/opinion articles). A total of 116 papers supported the neurotoxic effect (17 human research, 23 animal/in vitro, 60 case reports, 16 review/opinion articles). Nine papers supported no hypothesis (5 human research, 3 animal/in vitro, 0 case reports, 1 review/opinion articles). Overall, the grading suggests that the data concerning the effect of lithium therapy is that of level C, that is 'unclear or conflicting scientific evidence' since there is conflicting evidence from uncontrolled non-randomized studies accompanied by conflicting evidence from animal and basic science studies. Although more papers are in favour of the toxic effect, the great difference in the type of papers that support either hypothesis, along with publication bias and methodological issues make conclusions difficult. Lithium remains the 'gold standard' for the prophylaxis of bipolar illness, however, our review suggests that there is a rare possibility of a neurotoxic effect in real-life clinical practice even in closely monitored patients with 'therapeutic' lithium plasma levels. It is desirable to keep lithium blood levels as low as feasible with prophylaxis.

Hyperactive intracellular calcium dynamics in B lymphoblasts from patients with bipolar I disorder

Substantial evidence implicates abnormalities of intracellular calcium (Ca2+) dynamics in the pathophysiology of bipolar disorder (BD). However, the precise mechanisms underlying such disturbances are poorly understood. To further elaborate the nature of altered intracellular Ca2+ signalling dynamics that occur in BD, we examined receptor- and store-operated Ca2+ responses in B lymphoblast cell lines (BLCLs), which have been found in earlier studies to 'report' BD-associated disturbances. Basal Ca2+ concentrations ([Ca2+]B), and lysophosphatidic acid (LPA)- and thapsigargin-stimulated Ca2+ responses were determined in BLCLs from 52 BD-I patients and 30 healthy comparison subjects using fura-2, and ratiometric fluorometry. ANOVA revealed a significant effect of diagnosis, but not gender, on [Ca2+]B (F1,63=4.4, p=0.04) and the rate of rise (F1,63=5.2, p=0.03) of LPA-stimulated Ca2+ responses in BLCLs from patients compared with those from healthy subjects. A significant genderxdiagnosis interaction on the LPA-induced rate of rise (F1,63=4.6, p=0.03) was accounted for by a faster rate of rise (97%) in BLCLs from BD-I males compared with healthy males but not in those from female patients compared with healthy females. A genderxdiagnosis interaction in thapsigargin-evoked Ca2+ influx (F1,61=3.8, p=0.05) resulted from a significantly higher peak [Ca2+]influx (24%) in BLCLs from female compared with male patients. The results suggest more rapid LPA-stimulated Ca2+ responses occur in BLCLs from BD-I patients compared with controls, which are probably mediated, in part, by canonical transient receptor potential type 3 (TRPC3)-like channels. Additionally, this study highlights sex-dependent differences that can occur in the pathophysiological disturbances involved in BD.

Collaborative depression care, screening, diagnosis and specificity of depression treatments in the primary care setting

The identification, referral and specific treatment of midlife patients in primary care who are distressed by mood, anxiety, sleep and stress-related symptoms, with or without clinically confirmed menopausal symptoms, are confounded by many structural issues in the delivery of women's healthcare. Diagnosis, care delivery, affordability of treatment, time commitment for treatment, treatment specificity for a particular patient's symptoms and patient receptiveness to diagnosis and treatment all play roles in the successful amelioration of symptoms in this patient population. The value of screening for depression in primary care, the limitations of commonly used screening instruments relative to culture and ethnicity, and which clinical care systems make best use of diagnostic screening programs will be discussed in the context of the midlife woman. The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) program illustrates the relatively high rate of unremitted patients, regardless of clinical setting, who are receiving antidepressants. Nonmedication treatment approaches, referred to in the literature as 'nonsomatic treatments', for depression, anxiety and stress, include different forms of cognitive-behavioral therapy, interpersonal therapy, structured daily activities, mindfulness therapies, relaxation treatment protocols and exercise. The specificity of these treatments, their mechanisms of action, the motivation and time commitment required of patients, and the availability of trained practitioners to deliver them are reviewed. Midlife women with menopausal symptoms and depression/anxiety comorbidity represent a challenging patient population for whom an individualized treatment plan is often necessary. Treatment for depression comorbid with distressing menopausal symptoms would be facilitated by the implementation of a collaborative care program for depression in the primary care setting.

The role of glutamate in mood disorders: results from the ketamine in major depression study and the presumed cellular mechanism underlying its antidepressant effects

In this article, we first review a study showing that the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine leads to rapid, robust, and relatively sustained antidepressant effects in patients with treatment-resistant major depression. We then discuss our hypothesis that the therapeutic effects of monoaminergic antidepressants and ketamine may be mediated by increased AMPA-to-NMDA glutamate receptor throughput in critical neuronal circuits. We hypothesize that ketamine directly mediates this throughput, whereas monoaminergic antidepressants work indirectly and gradually; this may explain, in part, the lag of onset of several weeks to months that is observed with traditional antidepressants.

Role of BDNF in bipolar and unipolar disorder: clinical and theoretical implications

A number of lines of converging evidence suggest that brain-derived neurotrophic factor (BDNF) may play a role in the onset and treatment of bipolar disorder. We review pertinent data on BDNF from several different areas of preclinical and clinical investigation that suggest novel theoretical and treatment implications for the recurrent affective disorders. Data from several recent studies have also converged showing that the val66met allele of BDNF, a common single nucleotide polymorphism (SNP), is associated with selective minor deficits in cognitive functioning in subjects with schizophrenia, bipolar illness, and normal controls. Yet, paradoxically, the better functioning val66val allele of BDNF appears to be associated with an increased risk for bipolar disorder and perhaps early onset or rapid cycling. All the primary antidepressant modalities, as well as the mood stabilizers lithium and valproate, increase BDNF. Stressors decrease BDNF and this effect can be blocked by antidepressants. Serum BDNF is low in proportion to the severity of mania and depression and increases with clinical improvement. Assessment of the val66val BDNF allele and a range of other SNPs as potential vulnerability factors for bipolar illness and its early onset could facilitate studies of early intervention, help reduce long delays between the onset of first symptoms and the first treatment, and help in the prediction of individual patient's likelihood of responding to a given treatment.