Risk factors for development of depression and psychosis. Glucocorticoid receptors and pituitary implications for treatment with antidepressant and glucocorticoids

"Inflamed" depression: A review of the interactions between depression and inflammation and current anti-inflammatory strategies for depression

Depression is a common mental disorder, the effective treatment of which remains a challenging issue worldwide. The clinical pathogenesis of depression has been deeply explored, leading to the formulation of various pathogenic hypotheses. Among these, the monoamine neurotransmitter hypothesis holds a prominent position, yet it has significant limitations as more than one-third of patients do not respond to conventional treatments targeting monoamine transmission disturbances. Over the past few decades, a growing body of research has highlighted the link between inflammation and depression as a potential key factor in the pathophysiology of depression. In this review, we first summarize the relationship between inflammation and depression, with a focus on the pathophysiological changes mediated by inflammation in depression. The mechanisms linking inflammation to depression as well as multiple anti-inflammatory strategies are also discussed, and their efficacy and safety are assessed. This review broadens the perspective on specific aspects of using anti-inflammatory strategies for treating depression, laying the groundwork for advancing precision medicine for individuals suffering from "inflamed" depression.

Prediction and Validation of Hub Genes Related to Major Depressive Disorder Based on Co-expression Network Analysis

Major depressive disorder (MDD) is generally among the most prevalent psychiatric illnesses. Significant advances have occurred in comprehension of the MDD biology. However, it is still essential to recognize new biomarkers for potential targeted treatment of patients with MDD. The present work deals with in-depth comparative computational analyses to obtain new insights, such as gene ontology and pathway enrichment analyses and weighted gene co-expression network analysis (WGCNA) through gene expression dataset. The expression of selected hub-genes was validated in MDD patients using quantitative real-time PCR (RT-qPCR). We found that MDD progression includes the turquoise module genes (p-value = 1e-18, r = 0.97). According to gene enrichment analysis, the cytokine-mediated signaling pathway mostly involves genes in this module. By selection of four candidate hub-genes (IL6, NRG1, TNF, and BDNF), RT-qPCR validation was performed. A significant NRG1 downregulation was revealed by the RT-qPCR outcomes in MDD. In MDD patients, TNF and IL6 expression were considerably higher, and no considerable differences were found in the BDNF expression. Ultimately, based on ROC analyses, IL6, NRG1, and TNF had a higher MDD diagnostic performance. Therefore, our study presents information on the intricate association between MDD development and cytokine-mediated signaling, thus providing new rationales to develop new therapeutic approaches.

Effects of Cortisol Administration on Resting-State Functional Connectivity in Women with Depression

Previous resting-state functional connectivity (rsFC) research has identified several brain networks impacted by depression and cortisol, including default mode (DMN), frontoparietal (FPN), and salience networks (SN). In the present study, we examined the effects of cortisol administration on rsFC of these networks in individuals varying in depression history and severity. We collected resting-state fMRI scans and self-reported depression symptom severity for 74 women with and without a history of depression after cortisol and placebo administration using a double-blind, crossover design. We conducted seed-based rsFC analyses for DMN, FPN, and SN seeds to examine rsFC changes after cortisol vs. placebo administration in relation to depression history group and severity. Results revealed a main effect of depression group, with lower left amygdala (SN)-middle temporal gyrus connectivity in women with a history of depression. Cortisol administration increased insula (SN)-inferior frontal gyrus and superior temporal gyrus connectivity. We also found that greater depression severity was associated with increased PCC (DMN)-cerebellum connectivity after cortisol. These results did not survive Bonferroni correction for seed ROIs and should be interpreted with caution. Our findings indicate that acute cortisol elevation may normalize aberrant connectivity of DMN and SN regions, which could help inform clinical treatments for depression.

Early life adversity reduces affiliative behavior towards a distressed cagemate and leads to sex-specific alterations in corticosterone responses

Experiencing early life adversity (ELA) alters stress physiology and increases the risk for developing psychiatric disorders. The social environment can influence dynamics of stress responding and buffer and/or transfer stress across individuals. Yet, the impact of ELA on sensitivity to the stress of others and social behavior following stress is unknown. Here, to test the impact of ELA on social and physiological responses to stress, circulating blood corticosterone (CORT) and social behaviors were assessed in adult male and female mice reared under limited bedding and nesting (LBN) or control conditions. To induce stress, one cagemate of a pair-housed cage underwent a footshock paradigm and was then returned to their unshocked partner. CORT was measured in both mice 20 or 90 minutes after stress exposure, and social behaviors were recorded and analyzed. ELA rearing influenced the CORT response to stress in a sex-specific manner. In males, both control and ELA-reared mice exhibited similar stress transfer to unshocked cagemates and similar CORT dynamics. In contrast, ELA females showed a heightened stress transfer to unshocked cagemates, and sustained elevation of CORT relative to controls, indicating enhanced stress contagion and a failure to terminate the stress response. Behaviorally, ELA females displayed decreased allogrooming and increased investigative behaviors, while ELA males showed reduced huddling. Together, these findings demonstrate that ELA influenced HPA axis dynamics, social stress contagion and social behavior. Further research is needed to unravel the underlying mechanisms and long-term consequences of ELA on stress systems and their impact on behavioral outcomes.

Exploring the Heart-Mind Connection: Unraveling the Shared Pathways between Depression and Cardiovascular Diseases

Civilization diseases are defined as non-communicable diseases that affect a large part of the population. Examples of such diseases are depression and cardiovascular disease. Importantly, the World Health Organization warns against an increase in both of these. This narrative review aims to summarize the available information on measurable risk factors for CVD and depression based on the existing literature. The paper reviews the epidemiology and main risk factors for the coexistence of depression and cardiovascular disease. The authors emphasize that there is evidence of a link between depression and cardiovascular disease. Here, we highlight common risk factors for depression and cardiovascular disease, including obesity, diabetes, and physical inactivity, as well as the importance of the prevention and treatment of CVD in preventing depression and other mental disorders. Conversely, effective treatment of CVD can also help prevent depression and improve mental health outcomes. It seems advisable to introduce screening tests for depression in patients treated for cardiac reasons. Importantly, in patients treated for mood disorders, it is worth controlling CVD risk factors, for example, by checking blood pressure and pulse during routine visits. It is also worth paying attention to the mental condition of patients with CVD. This study underlines the importance of interdisciplinary co-operation.

Role of FKBP5 and its genetic mutations in stress-induced psychiatric disorders: an opportunity for drug discovery

Stress-induced mental health disorders are affecting many people around the world. However, effective drug therapy for curing psychiatric diseases does not occur sufficiently. Many neurotransmitters, hormones, and mechanisms are essential in regulating the body's stress response. One of the most critical components of the stress response system is the hypothalamus-pituitary-adrenal (HPA) axis. The FKBP prolyl isomerase 51 (FKBP51) protein is one of the main negative regulators of the HPA axis. FKBP51 negatively regulates the cortisol effects (the end product of the HPA axis) by inhibiting the interaction between glucocorticoid receptors (GRs) and cortisol, causing reduced transcription of downstream cortisol molecules. By regulating cortisol effects, the FKBP51 protein can indirectly regulate the sensitivity of the HPA axis to stressors. Previous studies have indicated the influence of FKBP5 gene mutations and epigenetic changes in different psychiatric diseases and drug responses and recommended the FKBP51 protein as a drug target and a biomarker for psychological disorders. In this review, we attempted to discuss the effects of the FKBP5 gene, its mutations on different psychiatric diseases, and drugs affecting the FKBP5 gene.

Maternal immune activation alters placental histone-3 lysine-9 tri-methylation, offspring sensorimotor processing, and hypothalamic transposable element expression in a sex-specific manner

Animal models of maternal immune activation (MIA) are central to identifying the biological mechanisms that underly the association between prenatal infection and neuropsychiatric disorder susceptibility. Many studies, however, have limited their scope to protein coding genes and their role in mediating this inherent risk, while much less attention has been directed towards exploring the roles of the epigenome and transposable elements (TEs). In Experiment 1, we demonstrate the ability of MIA to alter the chromatin landscape of the placenta. We induced MIA by injecting 200 μg/kg (i.p.) of lipopolysaccharide (LPS) on gestational day 15 in Sprague-Dawley rats. We found a sex-specific rearrangement of heterochromatin 24-h after exposure to MIA, as evidenced by an increase in histone-3 lysine-9 trimethylation (H3K9me3). In Experiment 2, MIA was associated with long-term sensorimotor processing deficits as indicated by reduced prepulse inhibition (PPI) of the acoustic startle reflex in adult male and female offspring and an increased mechanical allodynia threshold in males. Analyses of gene expression within the hypothalamus-chosen for its involvement in the sex-specific pathogenesis of schizophrenia and the stress response-revealed significantly higher levels of the stress-sensitive genes Gr and Fkbp5. Deleterious TE expression is often a hallmark of neuropsychiatric disease and we found sex-specific increases in the expression of several TEs including IAP, B2 SINE, and LINE-1 ORF1. The data from this study warrant the future consideration of chromatin stability and TEs as part of the mechanism that drives MIA-associated changes in the brain and behavior.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Elevated Serum IL-2 Levels are Associated With Major Depressive Disorder: A Case-Control Study

Objectives

Numerous earlier studies have stated an association between major depressive disorder (MDD) and altered expression of inflammatory process. However, it still needs to determine whether the alteration of cytokines is the causative factor or a consequence of this disorder. Therefore, we attempted to evaluate the role of the pro-inflammatory cytokine IL-2 in the pathophysiology of depression.

Methods

We collected blood samples from 111 MDD patients and 112 healthy controls (HCs) matched by age and sex. Diagnostic and statistical manual of mental disorders (DSM-5) score was used to assess study participants. We determined the severity of depression using the Hamilton Depression (Ham-D) rating scale. We assayed serum levels of IL-2 using the Enzyme-Linked Immunosorbent Assay (ELISA) kit.

Results

Elevated levels of IL-2 were detected in MDD patients than HCs (29.79 ± 6.18 and 12.77 ± 4.84 pg/ml, P < 0.05). We observed a higher level of IL-2 in female MDD patients compared to female HCs (31.98 ± 8.34 and 7.76 ± 0.36 pg/ml, P < 0.05). We witnessed a sex-specific correlation between the serum IL-2 levels and the Ham-D score and found that the females with higher Ham-D scores had higher serum IL-2 levels. Moreover, the ROC curve represented the good diagnostic performance of serum IL-2 levels as a biomarker with sensitivity and specificity values of 83.7% and 80.4%, respectively.

Conclusions

The current study findings indicate that elevated serum IL-2 levels are associated with MDD. This alteration may be the cause of triggering depression or a result of the activated inflammatory process during the depression. Therefore, we recommend further interventional research to clarify the actual reasons for these altered IL-2 levels in MDD patients.

Higher Concentration of Adrenocorticotropic Hormone Predicts Post-Stroke Depression

Background

Post-stroke depression (PSD) is the most common neuropsychiatric complication after stroke, seriously affecting the quality of survivors’ life. As one of the important causes of PSD, neuroendocrine mechanism has been widely studied in recent years. The main objective of this study was to investigate the relationship between adrenocorticotropic hormone (ACTH) on admission and PSD at 3 months.

Methods

This is a hospital-based prospective cohort study, which was conducted at three independent hospitals (Tongji Hospital, Wuhan First Hospital and Wuhan Central Hospital) between August 2018 and June 2019. A total of 768 ischemic stroke patients were finally eligible for analysis and categorized into equal tertiles according to the distribution of ACTH and the number of patients. The χ²-test, Mann–Whitney U-test and Kruskal–Wallis test were used to check for statistical significance. And restricted cubic spline (RCS) regression model was used to explore the non-linear relationship between continuous ACTH levels and PSD at 3 months.

Results

The optimal cut-off points of ACTH were as follows: (T1) 0.32–20.55 pg/mL, (T2) 20.56–39.79 pg/mL, (T3) 39.80–143.40 pg/mL. A total of 305 patients (39.7%) were diagnosed as PSD at 3 months follow-up. Significant differences were found between the PSD and non-PSD groups in ACTH concentration (P = 0.001). After adjustment for all conventional confounders, the odds ratios of PSD were 1.735 (95% CI = 1.176–2.560, P = 0.005) for the highest tertile of ACTH and 1.496 (95% CI = 1.019–2.194, P = 0.040) for the middle tertile of ACTH, as compared with the lowest tertile. In multiple-adjusted RCS regression, continuous ACTH showed saturation effect relation with PSD risk after 31.02 pg/mL (P for nonlinear = 0.0143).

Conclusion

Higher ACTH level on admission is a significant and independent biomarker to predict the development of PSD at 3 months follow-up. Besides, saturation effect was revealed even if the underlying mechanism is unclear. For stroke patients, doctors should pay attention to the baseline ACTH for screening high-risk PSD in clinical practice.

Targeting the Adaptive Immune System in Depression: Focus on T Helper 17 Cells

There is a vital need to understand mechanisms contributing to susceptibility to depression to improve treatments for the 11% of Americans who currently suffer from this debilitating disease. The adaptive immune system, comprising T and B cells, has emerged as a potential contributor to depression, as demonstrated in the context of lymphopenic mice. Overall, patients with depression have reduced circulating T and regulatory B cells, "immunosuppressed" T cells, and alterations in the relative abundance of T cell subtypes. T helper (Th) cells have the capacity to differentiate to various lineages depending on the cytokine environment, antigen stimulation, and costimulation. Regulatory T cells are decreased, and the Th1/Th2 ratio and the Th17 cells are increased in patients with depression. Evidence for changes in each Th lineage has been reported to some extent in patients with depression. However, the evidence is strongest for the association of depression with changes in Th17 cells. Th17 cells produce the inflammatory cytokine interleukin (IL)-17A, and the discovery of Th17 cell involvement in depression evolved from the well established link that IL-6, which is required for Th17 cell differentiation, contributes to the onset, and possibly maintenance, of depression. One intriguing action of Th17 cells is their participation in the gut-brain axis to mediate stress responses. Although the mechanisms of action of Th17 cells in depression remain unclear, neutralization of IL-17A by anti-IL-17A antibodies, blocking stress-induced production, or release of gut Th17 cells represent feasible therapeutic approaches and might provide a new avenue to improve depression symptoms. SIGNIFICANCE STATEMENT: Th17 cells appear as a promising therapeutic target for depression, for which efficacious therapeutic options are limited. The use of neutralizing antibodies targeting Th17 cells has provided encouraging results in depressed patients with comorbid autoimmune diseases.

Let's talk about sex: Differences in drug therapy in males and females

Professor Henry Higgins in My Fair Lady said, 'Why can't a woman be more like a man?' Perhaps unintended, such narration extends to the reality of current drug development. A clear sex-gap exists in pharmaceutical research spanning from preclinical studies, clinical trials to post-marketing surveillance with a bias towards males. Consequently, women experience adverse drug reactions from approved drug products more often than men. Distinct differences in pharmaceutical response across drug classes and the lack of understanding of disease pathophysiology also exists between the sexes, often leading to suboptimal drug therapy in women. This review explores the influence of sex as a biological variable in drug delivery, pharmacokinetic response and overall efficacy in the context of pharmaceutical research and practice in the clinic. Prospective recommendations are provided to guide researchers towards the consideration of sex differences in methodologies and analyses. The promotion of disaggregating data according to sex to strengthen scientific rigour, encouraging innovation through the personalisation of medicines and adopting machine learning algorithms is vital for optimised drug development in the sexes and population health equity.

Hypothalamic-Pituitary-End-Organ Axes: Hormone Function in Female Patients with Major Depressive Disorder

Classic hypothalamic-pituitary-end-organ feedback loops - the hypothalamic-pituitary-adrenal axis (HPAA), hypothalamic-pituitary-thyroidal axis (HPTA), and hypothalamic-pituitary-gonadal axis (HPGA) - are associated with the neuroendocrine and immune systems in major depressive disorder (MDD). Female patients with MDD present with evident neuroendocrine and immunological changes. Glucocorticoid, thyroid hormone, and reproductive steroid levels fluctuate with menstrual cycles, which might lead to glucocorticoid receptor resistance, impairment of triiodothyronine conversion, and sex hormone secretion disorders. In this review, we summarize the independent and interactive functions of these three axes in female MDD patients. The similar molecular structure of steroids implies an interrelationship between the hypothalamic-pituitary-end-organ axes and the competitive inhibitory effects at the receptor level, especially when considering the HPAA and HPGA.

Neurobiology of resilience in depression: immune and vascular insights from human and animal studies

Major depressive disorder (MDD) is a chronic and recurrent psychiatric condition characterized by depressed mood, social isolation and anhedonia. It will affect 20% of individuals with considerable economic impacts. Unfortunately, 30-50% of depressed individuals are resistant to current antidepressant treatments. MDD is twice as prevalent in women and associated symptoms are different. Depression's main environmental risk factor is chronic stress, and women report higher levels of stress in daily life. However, not every stressed individual becomes depressed, highlighting the need to identify biological determinants of stress vulnerability but also resilience. Based on a reverse translational approach, rodent models of depression were developed to study the mechanisms underlying susceptibility vs resilience. Indeed, a subpopulation of animals can display coping mechanisms and a set of biological alterations leading to stress resilience. The aetiology of MDD is multifactorial and involves several physiological systems. Exacerbation of endocrine and immune responses from both innate and adaptive systems are observed in depressed individuals and mice exhibiting depression-like behaviours. Increasing attention has been given to neurovascular health since higher prevalence of cardiovascular diseases is found in MDD patients and inflammatory conditions are associated with depression, treatment resistance and relapse. Here, we provide an overview of endocrine, immune and vascular changes associated with stress vulnerability vs. resilience in rodents and when available, in humans. Lack of treatment efficacy suggests that neuron-centric treatments do not address important causal biological factors and better understanding of stress-induced adaptations, including sex differences, could contribute to develop novel therapeutic strategies including personalized medicine approaches.

Corticosterone as a Potential Confounding Factor in Delineating Mechanisms Underlying Ketamine's Rapid Antidepressant Actions

Recent research into the rapid antidepressant effect of subanesthetic doses of ketamine have identified a series of relevant protein cascades activated within hours of administration. Prior to, or concurrent with, these activation cascades, ketamine treatment generates dissociative and psychotomimetic side effects along with an increase in circulating glucocorticoids. In rats, we observed an over 3-fold increase in corticosterone levels in both serum and brain tissue, within an hour of administration of low dose ketamine (10 mg/kg), but not with (2R, 6R)-hydroxynorketamine (HNK) (10 mg/kg), a ketamine metabolite shown to produce antidepressant-like action in rodents without inducing immediate side-effects. Hippocampal tissue from ketamine, but not HNK, injected animals displayed a significant increase in the expression of sgk1, a downstream effector of glucocorticoid receptor signaling. To examine the role conscious sensation of ketamine's side effects plays in the release of corticosterone, we assessed serum corticosterone levels after ketamine administration while under isoflurane anesthesia. Under anesthesia, ketamine failed to increase circulating corticosterone levels relative to saline controls. Concurrent with its antidepressant effects, ketamine generates a release of glucocorticoids potentially linked to disturbing cognitive side effects and the activation of distinct molecular pathways which should be considered when attempting to delineate the molecular mechanisms of its antidepressant function.

FKBP5 polymorphisms induce differential glucocorticoid responsiveness in primary CNS cells - First insights from novel humanized mice

The brain is a central hub for integration of internal and external conditions and, thus, a regulator of the stress response. Glucocorticoids are the essential communicators of this response. Aberrations in glucocorticoid signaling are a common symptom in patients with psychiatric disorders. The gene FKBP5 encodes a chaperone protein that functionally inhibits glucocorticoid signaling and, thus, contributes to the regulation of stress. In the context of childhood trauma, differential expression of FKBP5 has been found in psychiatric patients compared to controls. These variations in expression levels of FKBP5 were reported to be associated with differences in stress responsiveness in human carriers of the single nucleotide polymorphism (SNP) rs1360780. Understanding the mechanisms underlying FKBP5 polymorphism‐associated glucocorticoid responsiveness in the CNS will lead to a better understanding of stress regulation or associated pathology. To study these mechanisms, two novel humanized mouse lines were generated. The lines carried either the risk (A/T) allele or the resilient (C/G) allele of rs1360780. Primary cells from CNS (astrocytes, microglia, and neurons) were analyzed for their basal expression levels of FKBP5 and their responsiveness to glucocorticoids. Differential expression of FKBP5 was found for these cell types and negatively correlated with the cellular glucocorticoid responsiveness. Astrocytes revealed the strongest transcriptional response, followed by microglia and neurons. Furthermore, the risk allele (A/T) was associated with greater induction of FKBP5 than the resilience allele. Novel FKBP5‐humanized mice display differential glucocorticoid responsiveness due to a single intronic SNP. The vulnerability to stress signaling in the shape of glucocorticoids in the brain correlated with FKBP5 expression levels. The strong responsiveness of astrocytes to glucocorticoids implies astrocytes play a prominent role in the stress response, and in FKBP5‐related differences in glucocorticoid signaling. The novel humanized mouse lines will allow for further study of the role that FKBP5 SNPs have in risk and resilience to stress pathology.

Anti-Stress Properties of Atypical Antipsychotics

Stress exposure represents a major environmental risk factor for schizophrenia and other psychiatric disorders, as it plays a pivotal role in the etiology as well as in the manifestation of disease symptomatology. It may be inferred that pharmacological treatments must be able to modulate the behavioral, functional, and molecular alterations produced by stress exposure to achieve significant clinical outcomes. This review aims at examining existing clinical and preclinical evidence that supports the ability of atypical antipsychotic drugs (AAPDs) to modulate stress-related alterations. Indeed, while the pharmacodynamic differences between AAPDs have been extensively characterized, less is known on their ability to regulate downstream mechanisms that are critical for functional recovery and patient stabilization. We will discuss stress-related mechanisms, spanning from neuroendocrine function to inflammation and neuronal plasticity, which are relevant for the manifestation of schizophrenic symptomatology, and we will discuss if and how AAPDs may interfere with such mechanisms. Considering the impact of stress in everyday life, we believe that a better understanding of the potential effects of AAPDs on stress-related mechanisms may provide novel and important insights for improving therapeutic strategies aimed at promoting coping mechanisms and enhancing the quality of life of patients affected by psychiatric disorders.

Glucocorticoids prime the inflammatory response of human hippocampal cells through up-regulation of inflammatory pathways

Increased pro-inflammatory cytokines and an overactive hypothalamic-pituitary-adrenal (HPA) axis have both been implicated in the pathogenesis of depression. However, these explanations appear contradictory because glucocorticoids are well recognised for their anti-inflammatory effects. Two hypotheses exist to resolve this paradox: the mediating presence of glucocorticoid receptor resistance, or the possibility that glucocorticoids can potentiate inflammatory processes in some circumstances. We sought to investigate these hypotheses in a cell model with significant relevance to depression: human hippocampal progenitor cells. We demonstrated that dexamethasone in vitro given for 24 hours and followed by a 24 hours rest interval before an immune challenge potentiates inflammatory effects in these neural cells, that is, increases the IL-6 protein secretion induced by stimulation with IL-1β (10 ng/mL for 24 hours) by + 49% (P < 0.05) at a concentration of 100 nM and by + 70% (P < 0.01) for 1 μM. These effects are time- and dose-dependent and require activation of the glucocorticoid receptor. Gene expression microarray assays using Human Gene 2.1st Array Strips demonstrated that glucocorticoid treatment up-regulated several innate immune genes, including chemokines and Nod-like receptor, NLRP6; using transcription factor binding motifs we found limited evidence that glucocorticoid resistance was induced in the cells. Our data suggests a mechanism by which stress may prime the immune system for increased inflammation and suggests that stress and inflammation may be synergistic in the pathogenesis of depression.

Corticosterone Induces Depressive-Like Behavior in Female Peri-Pubescent Rats, but Not in Pre-Pubescent Rats

Background

There are no data on the effect of exogenous corticosterone on depressive-like behavior in juvenile rats. Furthermore, it has not been tested whether the effects of corticosterone in female rats is different before or after puberty.

Objective

We tested the effect of corticosterone treatment on female pre- and peri-pubescent juvenile rats on depressive-like behavior.

Methods

Female juvenile rats were divided into pre-pubescent (post-natal day 7–27) or peri-pubescent (post-natal day 28–48) groups and administered daily corticosterone (40 mg kg⁻¹day⁻¹) for 21 days. Depressive-like behavior was assessed using a modified forced swim test and the sucrose preference test. After behavioral assessment, brains were analyzed to determine if there were changes in cell proliferation and newborn neuron survival in the dentate gyrus of the dorsal hippocampus.

Results

Chronic corticosterone treatment did not affect behavior or neurogenesis in female pre-pubescent juvenile rats. However, female peri-pubescent rats injected with corticosterone showed increased depressive-like behavior as well as a decrease in cell proliferation in the subgranular zone. Furthermore, there was an inverse correlation between time spent immobile in the forced swim test and cell proliferation in the granule cell layer in peri-pubescent rats.

Conclusions

Corticosterone induces depressive-like behavior in peri-pubescent, but not in pre-pubescent female rats. Finally, our results suggest that depressive-like behavior may be associated with a decrease in hippocampal cell proliferation in female peri-pubescent rats.

Comparison of short-term (saliva) and long-term (hair) cortisol levels in out-patients with melancholic and non-melancholic major depression

BACKGROUND

Major depressive episodes (MDEs) show diverse cortisol level alterations. Heterogeneity in symptom profiles, symptom severity and cortisol specimens may explain these heterogeneous results. Less severely ill out-patients with a non-melancholic MDE (NM-MDE) may have a variation in the rhythm of cortisol secretion rather than in its concentration.

METHOD

Cortisol measures were taken (a) over a short-term period (12 h) by measuring daily salivary output using the area under the curve with respect to the ground (AUCg) and (b) over a long-term period (3 months) in hair. Additionally, cortisol reactivity measures in saliva - the cortisol awakening response and the 30 min delta cortisol secretion after awakening (DELTA) - were investigated in 19 patients with a melancholic MDE (M-MDE) and 52 with a NM-MDE, and in 40 matched controls who were recruited from the UK and Chile. Depression severity scores were correlated with different cortisol measures.

RESULTS

The NM-MDE group showed a decreased AUCg in comparison with controls (P = 0.02), but normal cortisol reactivity and long-term cortisol levels. The M-MDE group did not exhibit any significant cortisol alterations nor an association with depression severity scores. Higher Hamilton Rating Scale for Depression score was linked with decreased hair cortisol concentration (HCC, P = 0.05) and higher DELTA (P = 0.04) in NM-MDEs, whereas decreased HCC was the sole alteration associated with out-patients with severe M-MDEs.

CONCLUSIONS

The contrasting short- and long-term cortisol output results are compatible with an alteration in the rhythm of cortisol secretion in NM-MDEs. This alteration may consist of large and/or intense episodes of hypercortisolaemia in moderate NM-MDEs and frequent, but brief and sharp early-morning DELTAs in its severe form. These changes may reflect the effects of environmental factors or episodes of nocturnal hypercortisolaemia that were not measured by the short-term samples used in this study.

Effect of lurasidone treatment on chronic mild stress-induced behavioural deficits in male rats: The potential role for glucocorticoid receptor signalling

BACKGROUND

Stress represents one of the main precipitating factors for psychiatric diseases, characterised by an altered function of glucocorticoid receptors (GR), known to play a role in mood and cognitive function. We investigated the ability of the antipsychotic lurasidone to modulate the involvement of genomic and non-genomic GR signalling in the behavioural alterations due to chronic stress exposure.

METHODS

Male Wistar rats were exposed to seven weeks of chronic mild stress (CMS) and treated with lurasidone (3 mg/kg/day) starting from the second week of stress for more five weeks. Gene expression and protein analyses were conducted in dorsal hippocampus.

RESULTS

Seven weeks of CMS induced anhedonia and cognitive impairment, which were normalised by lurasidone. At molecular level, CMS rats showed an increase of GR protein levels by 60% (p<0.001 vs. CTRL/VEH) in the membrane compartment, which was paralleled by an up-regulation of phosphoSINAPSYN Ia/b by 88% (p<0.01 vs. CTRL/VEH) and of the mitochondrial marker Cox3 by 21% (p<0.05 vs. CTRL/VEH). Moreover, while exposure to the novel object recognition test increased the nuclear translocation of GRs by 96% (p<0.01 vs. CTRL/VEH/Naïve) and their transcriptional activity in non-stressed rats, such mechanisms were impaired in CMS rats. Interestingly, the genomic and non-genomic alterations of GR, induced by CMS, were normalised by lurasidone.

CONCLUSION

Our results further support the role of glucocorticoid signalling in the dysfunction associated with stress exposure. We provide novel insights on the mechanism of lurasidone, suggesting its effectiveness on different domains associated with psychiatric disorders.

Role of nociceptin/orphanin FQ and nociceptin opioid peptide receptor in depression and antidepressant effects of nociceptin opioid peptide receptor antagonists

Nociceptin/orphanin FQ (N/OFQ) and its receptor, nociceptin opioid peptide (NOP) receptor, are localized in brain areas implicated in depression including the amygdala, bed nucleus of the stria terminalis, habenula, and monoaminergic nuclei in the brain stem. N/OFQ inhibits neuronal excitability of monoaminergic neurons and monoamine release from their terminals by activation of G protein-coupled inwardly rectifying K⁺ channels and inhibition of voltage sensitive calcium channels, respectively. Therefore, NOP receptor antagonists have been proposed as a potential antidepressant. Indeed, mounting evidence shows that NOP receptor antagonists have antidepressant-like effects in various preclinical animal models of depression, and recent clinical studies again confirmed the idea that blockade of NOP receptor signaling could provide a novel strategy for the treatment of depression. In this review, we describe the pharmacological effects of N/OFQ in relation to depression and explore the possible mechanism of NOP receptor antagonists as potential antidepressants.

Effects of SSRIs on peripheral inflammatory cytokines in patients with Generalized Anxiety Disorder

BACKGROUND

Extensive research into psychoneuroimmunology has led to substantial advances in our understanding of the reciprocal interactions between the central nervous system and the immune system in neuropsychiatric disorders. To date, inflammation has been implicated in the pathogenesis of depression and anxiety. The immunomodulating effects of antidepressants on depression have been reported, however, there is no evidence of the similar effects of antidepressants on anxiety. The aim of the study was to investigate the effects of selective serotonin reuptake inhibitors (SSRIs) on peripheral inflammatory cytokines in patients with first episode generalized anxiety disorder (GAD).

METHODS

A prospective cohort design was employed: 42 patients with first episode GAD were treated with either escitalopram or sertraline for 12 weeks. Anxiety was measured by the Generalized Anxiety Disorder Scale and the State Trait Anxiety Inventory, serum pro-inflammatory cytokine levels were measured by the enzyme-linked immunosorbent assay (ELISA), and CRP determined by an immunoturbidimetric method before and after SSRIs treatment RESULTS: Baseline levels of anxiety and pro-inflammatory cytokines including IL-1α, IL-6, IL-8, IL-12, IFN-γ, and CRP were significantly reduced after treatment of SSRIs (p < 0.05 in all cases). In addition, the change of anxiety measures co-vary with the change of peripheral cytokine levels (p < 0.05 in all cases). The regression model revealed that log transformed baseline levels of CRP and IL-6 predicted treatment response (p < 0.05 in both cases).

CONCLUSIONS

This study is the first to investigate the effects of SSRIs on pro-inflammatory cytokines in patients with first episode GAD. The findings indicate moderate acute anti-inflammatory effects of SSRIs in GAD, and suggest that these anti-inflammatory effects may underlie anxiolytic effects of SSRIs. The study also indicates that serum levels of CRP and IL-6 may predict treatment response. However, data from randomized controlled trials is warranted to confirm these findings.

Depression comorbid with hyperalgesia: Different roles of neuroinflammation induced by chronic stress and hypercortisolism

BACKGROUND

Recent studies have indicated that inflammatory pathways and hypothalamic-pituitary-adrenal (HPA) axis function may be responsible for the interaction between pain and depression.

METHODS

Animals were examined for depressive and painful behavior following exposure to chronic unpredictable mild stress (CUMS) and chronic corticosterone (CORT) treatment. Subsequently, serum cytokines, adrenocorticotropic hormone (ACTH) and CORT were measured by enzyme-linked immunosorbent assay (ELISA). mRNA expression of cytokines in the brain were measured by quantitative PCR (qPCR).

RESULTS

The present study found that both CUMS and chronic CORT treatment induced behavioral changes of depression comorbid hyperalgesia. Moreover, both the treatments increased levels of serum ACTH, CORT, and cytokines including tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL1ß), interleukin 6 (IL6), and Caspase 1 (CASP1). Following CUMS, Il1ß levels were found to be elevated in all examined regions, including the raphe nuclei, thalamus, hippocampus, prefrontal cortex, and pituitary. In the raphe nuclei particularly, CUMS elevated all examined cytokine levels. Chronic CORT treatment, however, produced Il1ß elevation in the hippocampus and the pituitary, with showing elevated levels in all examined cytokines.

LIMITATION

To clarify the causal relationship between behavioral changes and altered cytokine levels via either antidepressant treatment or blockage of pre-inflammatory cytokine production, further studies should be conducted.

CONCLUSIONS

Despite similar behavioral consequences, hypercortisolism and peripheral inflammation, CUMS and chronic CORT treatment seem to produce differing inflammatory brain responses.

Associations between subclinical depressive symptoms and reduced brain volume in middle-aged to older adults

OBJECTIVES

The associations between subclinical depressive symptoms, as well specific symptom subscales, on brain structure in aging are not completely elucidated. This study investigated the extent to which depressive symptoms were related to brain volumes in fronto-limbic structures in a sample of middle-aged to older adults.

METHOD

Eighty participants underwent structural neuroimaging and completed the Beck Depression Inventory, 2nd Edition (BDI-II), which comprises separate affective, cognitive, and somatic subscales. Gray matter volumes were extracted from the caudal and rostral anterior cingulate, posterior cingulate, hippocampus, and amygdala. Hierarchical regression models examined the relationship between brain volumes and (i) total depressive symptoms and (ii) BDI-II subscales were conducted.

RESULTS

After adjusting for total intracranial volume, race, and age, higher total depressive symptoms were associated with smaller hippocampal volume (p = 0.005). For the symptom subscales, after controlling for the abovementioned covariates and the influence of the other symptom subscales, more somatic symptoms were related to smaller posterior cingulate (p = 0.025) and hippocampal (p < 0.001) volumes. In contrast, the affective and cognitive subscales were not associated with brain volumes in any regions of interest.

CONCLUSION

Our data showed that greater symptomatology was associated with smaller volume in limbic brain regions. These findings provide evidence for preclinical biological markers of major depression and specifically advance knowledge of the relationship between subclinical depressive symptoms and brain volume. Importantly, we observed variations by specific depressive symptom subscales, suggesting a symptom-differential relationship between subclinical depression and brain volume alterations in middle-aged and older individuals.

SSRIs and SNRIs (SRI) in Pregnancy: Effects on the Course of Pregnancy and the Offspring: How Far Are We from Having All the Answers?

Serotonin has important roles in the development of the brain and other organs. Manipulations of synaptic serotonin by drugs such as serotonin reuptake inhibitors (SRI) or serotonin norepinephrine reuptake inhibitors (SNRI) might alter their development and function. Of interest, most studies on the outcome of prenatal exposure to SRI in human have not found significant embryonic or fetal damage, except for a possible, slight increase in cardiac malformations. In up to a third of newborns exposed to SRI, exposure may induce transient neonatal behavioral changes (poor neonatal adaptation) and increased rate of persistent pulmonary hypertension. Prenatal SRI may also cause slight motor delay and language impairment but these are transient. The data on the possible association of prenatal SRIs with autism spectrum disorder (ASD) are inconsistent, and seem to be related to pre-pregnancy treatment or to maternal depression. Prenatal SRIs also appear to affect the hypothalamic hypophyseal adrenal (HPA) axis inducing epigenetic changes, but the long-term consequences of these effects on humans are as yet unknown. SRIs are metabolized in the liver by several cytochrome P450 (CYP) enzymes. Faster metabolism of most SRIs in late pregnancy leads to lower maternal concentrations, and thus potentially to decreased efficacy which is more prominent in women that are rapid metabolizers. Studies suggest that the serotonin transporter SLC6A4 promoter is associated with adverse neonatal outcomes after SRI exposure. Since maternal depression may adversely affect the child's development, one has to consider the risk of SRI discontinuation on the fetus and the child. As with any drug treatment in pregnancy, the benefits to the mother should be considered versus the possible hazards to the developing embryo/fetus.

Short- and long-term alterations of FKBP5-GR and specific microRNAs in the prefrontal cortex and hippocampus of male rats induced by adolescent stress contribute to depression susceptibility

Maladaptation of the hypothalamic-pituitary-adrenal (HPA) axis is involved in susceptibility to depression. Glucocorticoid receptors (GRs) and the co-chaperone protein, FK506 binding protein 51 (FKBP5), play crucial roles in dysfunction of the HPA axis. Further, certain microRNAs (miRNAs), such as miR-124a and miR-18a, which could reduce GR protein expression, contribute to affective disorders, while miR-511 as a regulator of FKBP5 is involved in an increased risk of depression. However, the short-term and persistent impacts of adolescent stress on miR-124a, miR-18a, and miR-511 expressions in the brain are unknown. Using depression models of chronic unpredictable mild stress (CUMS) or dexamethasone administration of adolescent rats, the authors of the present study probed the depressive-like behaviors, GR and FKBP5 expressions, and miR-124a, miR-18a, and miR-511 expressions in the prefrontal cortex and hippocampus. The GR antagonist RU486 was used as intervention. The results revealed that both CUMS and dexamethasone administration in the adolescent period resulted in anhedonia, altered locomotor behaviors, anxiety, and cognitive impairment. A remarkable decrease in GR expression, and increase in FKBP5, miR-124a, and miR-18a expressions were detected in the prefrontal cortex and hippocampus of adolescent rats. Furthermore, the similar long-term changes on behaviors and expressions of GR, FKBP5 and GR-related microRNAs were found in the adult rats following CUMS and dexamethasone treatment in adolescence. However, reduced miR-511 expression was observed only in the prefrontal cortex of adult rats exposed to adolescent CUMS or dexamethasone administration. These data suggested that the downregulation of GR, upregulation of FKBP5, miR-124a, and miR-18a in the prefrontal cortex and hippocampus, and downregulation of miR-511 in the prefrontal cortex were relevant to depressive-like behaviors.

Neurobiology and Therapeutic Potential of Cyclooxygenase-2 (COX-2) Inhibitors for Inflammation in Neuropsychiatric Disorders

Neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and neurodevelopmental disorders such as autism spectrum disorder, are associated with significant illness burden. Accumulating evidence supports an association between these disorders and inflammation. Consequently, anti-inflammatory agents, such as the cyclooxygenase-2 inhibitors, represent a novel avenue to prevent and treat neuropsychiatric illness. In this paper, we first review the role of inflammation in psychiatric pathophysiology including inflammatory cytokines' influence on neurotransmitters, the hypothalamic-pituitary-adrenal axis, and microglial mechanisms. We then discuss how cyclooxygenase-2-inhibitors influence these pathways with potential therapeutic benefit, with a focus on celecoxib, due to its superior safety profile. A search was conducted in PubMed, Embase, and PsychINFO databases, in addition to Clinicaltrials.gov and the Stanley Medical Research Institute trial registries. The results were presented as a narrative review. Currently available outcomes for randomized controlled trials up to November 2017 are also discussed. The evidence reviewed here suggests cyclooxygenase-2 inhibitors, and in particular celecoxib, may indeed assist in treating the symptoms of neuropsychiatric disorders; however, further studies are required to assess appropriate illness stage-related indication.

Alterations in Systemic and Cognitive Glucocorticoid Sensitivity in Depression

BACKGROUND

Decades of research point to cortisol insensitivity as a biomarker of depression. Despite a vast literature on cortisol's effects on memory, the role of cortisol insensitivity in core psychological features of depression, such as emotional memory biases, is unknown.

METHODS

Sixty-five premenopausal women with varying levels of depression completed this study involving an at-home low-dose dexamethasone suppression test and four experimental sessions (i.e., two visits for memory encoding of emotionally arousing pictures, each of which was followed 48 hours later by a recall test). Participants received 20 mg of oral cortisol (CORT) or placebo prior to encoding. We tested whether systemic cortisol insensitivity measured with the dexamethasone suppression test predicted cognitive sensitivity to CORT, which was operationalized as the change in negatively biased memory formation for pictures encoded following CORT versus placebo administration.

RESULTS

Cortisol insensitivity was associated with more severe depression and flatter diurnal cortisol levels. Cortisol insensitivity predicted negative memory bias for pictures encoded during the placebo session and reduction in negative memory bias for pictures encoded during the CORT (compared with placebo) session, even after accounting for psychiatric symptomatology.

CONCLUSIONS

Our findings replicate research showing that cortisol insensitivity predicts depression severity and flatter diurnal cortisol levels. The results further suggest that systemic cortisol insensitivity is related to negative memory bias and its alleviation by cortisol administration. These novel cognitive findings tie together knowledge regarding endocrine and psychological dysfunction in depression and suggest that boosting cortisol signal may cognitively benefit individuals with cortisol insensitivity.

LUMAN/CREB3 Plays a Dual Role in Stress Responses as a Cofactor of the Glucocorticoid Receptor and a Regulator of Secretion

LUMAN/CREB3, originally identified through its interaction with a cell cycle regulator HCFC1, is a transcription factor involved in the unfolded protein response during endoplasmic reticulum stress. Previously using gene knockout mouse models, we have shown that LUMAN modulates the glucocorticoid (GC) response leading to enhanced glucocorticoid receptor (GR) activity and lower circulating GC levels. Consequently, the stress response is dysregulated, leading to a blunted stress response in the Luman-deficient mice. One question that remained was how LUMAN deficiency affected the stress response at the cellular level leading to the changes in the physiological stress response. Here, we found that LUMAN interacts with GR through a putative nuclear receptor box site and can activate GR in the absence of a ligand. Further investigation showed that, when activated, LUMAN binds to the glucocorticoid response element (GRE), increasing the activity of GR exponentially compared to GR-ligand binding alone. On the other hand, we also found that in the absence of LUMAN, cells were more sensitive to cellular stress, exhibiting decreased secretory capacity. Hence our current data suggest that LUMAN may function both as a transcriptional cofactor of GR and a hormone secretion regulator, and through this, plays a role in stress sensitivity and reactivity to stress.

Visualizing BDNF Transcript Usage During Sound-Induced Memory Linked Plasticity

Activity-dependent BDNF (brain-derived neurotrophic factor) expression is hypothesized to be a cue for the context-specificity of memory formation. So far, activity-dependent BDNF cannot be explicitly monitored independently of basal BDNF levels. We used the BLEV (BDNF-live-exon-visualization) reporter mouse to specifically detect activity-dependent usage of Bdnf exon-IV and -VI promoters through bi-cistronic co-expression of CFP and YFP, respectively. Enriching acoustic stimuli led to improved peripheral and central auditory brainstem responses, increased Schaffer collateral LTP, and enhanced performance in the Morris water maze. Within the brainstem, neuronal activity was increased and accompanied by a trend for higher expression levels of Bdnf exon-IV-CFP and exon-VI-YFP transcripts. In the hippocampus BDNF transcripts were clearly increased parallel to changes in parvalbumin expression and were localized to specific neurons and capillaries. Severe acoustic trauma, in contrast, elevated neither Bdnf transcript levels, nor auditory responses, parvalbumin or LTP. Together, this suggests that critical sensory input is essential for recruitment of activity-dependent auditory-specific BDNF expression that may shape network adaptation.

Combined early life stressors: Prenatal nicotine and maternal deprivation interact to influence affective and drug seeking behavioral phenotypes in rats

Early life stress (ELS) increases the risk for later cognitive and emotional dysfunction, and has been implicated in the etiology of multiple psychiatric disorders. We hypothesize that combined insults during gestation and infancy, critical periods of neural development, could exacerbate neuropsychiatric outcomes in later life. Thus, we investigated the effects of maternal deprivation (MD) stress alone or combined with prenatal nicotine exposure (PNE) on negative affective states, ethanol drinking, and development of mesolimbic loci that regulate depression and drug dependence. On the elevated plus maze (EPM), MD rats exhibited ∼50% increase in risk-taking behavior/decreased anxiety when compared to control, but the combined MD + PNE did not affect this specific behavior. In the open field test, however, both MD and MD + PNE groups showed 2-fold greater locomotor activity. Furthermore, whereas MD showed greater latency to fall at 40 RPM on the rotarod compared to control, the MD + PNE animals' latency to fall was significantly greater at all RPMs tested, with an approximate 15% enhancement in motor coordination overall compared to control and MD. Analyses of depressive symptomatology with the forced swim test (FST) yielded 2- and 3-fold higher immobility times in MD and MD + PNE respectively. When tested in an operant drinking paradigm to quantify the effect of treatment on 10%v/v ethanol drinking, the MD and MD + PNE groups showed heightened ethanol consumption by ∼3- and 2-fold respectively. However, the experience of PNE reduced ethanol consumption in adults relative to MD alone. To test the stressors' impact on neurons in the amygdala and ventral tegmental area (VTA), mesolimbic anatomical regions associated with mood and reward, unbiased stereological measurements were performed and revealed ∼15% increase in number and density of neurons in the amygdala for both MD and MD + PNE, and ∼13% reduction in dopaminergic-like neurons in the VTA compared to control. We report here that multiple early stressors including prenatal nicotine and MD can modulate the neuroanatomy of the amygdala and VTA. These early life stressors can interact to influence the development of depressive-like and addictive behaviors.

Suggested Biomarkers for Major Depressive Disorder

Currently, the diagnosis of major depressive disorder (MDD) mainly relies on clinical examination and subjective evaluation of depressive symptoms. There is no non-invasive, quantitative test available today for the diagnosis of MDD. In MDD, exploration of biomarkers will be helpful in diagnosing the disorder as well as in choosing a treatment, and predicting the treatment response. In this article, it is aimed to review the findings of suggested biomarkers such as growth factors, cytokines and other inflammatory markers, oxidative stress markers, endocrine markers, energy balance hormones, genetic and epigenetic features, and neuroimaging in MDD and to evaluate how these findings contribute to the pathophysiology of MDD, the prediction of treatment response, severity of the disorder, and identification of subtypes. Among these, the findings related to the brain-derived neurotrophic factor, the hypothalamo-pituitary-adrenal axis, cytokines, and neuroimaging may be strong candidates for being biomarkers MDD, and may provide critical information in understanding biological etiology of depression. Although the findings are not sufficient yet, we think that the results of epigenetic studies will also provide very important contributions to the biomarker research in MDD. The availability of biomarkers in MDD will be an advancement that will facilitate the diagnosis of the disorder, treatment choices in the early stages, and prediction of the course of the disorder.

Glia- and tissue-specific changes in the Kynurenine Pathway after treatment of mice with lipopolysaccharide and dexamethasone

Behavioral symptoms associated with mood disorders have been intimately linked with immunological and psychological stress. Induction of immune and stress pathways is accompanied by increased tryptophan entry into the Kynurenine (Kyn) Pathway as governed by the rate-limiting enzymes indoleamine/tryptophan 2,3-dioxygenases (DO's: Ido1, Ido2, Tdo2). Indeed, elevated DO expression is associated with inflammation- and stress-related depression symptoms. Here we examined central (brain, astrocyte and microglia) and peripheral (lung, liver and spleen) DO expression in mice treated intraperitoneally with lipopolysaccharide (LPS) and dexamethasone (DEX) to model the response of the Kyn Pathway to inflammation and glucocorticoids. LPS-induced expression of cytokines in peripheral tissues was attenuated by DEX, confirming inflammatory and anti-inflammatory responses, respectively. Increased Kyn levels following LPS and DEX administration verified Kyn Pathway activation. Expression of multiple mRNA isoforms for each DO, which we have shown to be differentially utilized and regulated, were quantified including reference/full-length (FL) and variant (v) transcripts. LPS increased Ido1-FL in brain (∼1000-fold), a response paralleled by increased expression in both astrocytes and microglia. Central Ido1-FL was not changed by DEX; however, LPS-induced Ido1-FL was decreased by DEX in peripheral tissues. In contrast, DEX increased Ido1-v1 expression by astrocytes and microglia, but not peripheral tissues. In comparison, brain Ido2 was minimally induced by LPS or DEX. Uniquely, Ido2-v6 was LPS- and DEX-inducible in astrocytes, suggesting a unique role for astrocytes in response to inflammation and glucocorticoids. Only DEX increased central Tdo2 expression; however, peripheral Tdo2 was upregulated by either LPS or DEX. In summary, specific DO isoforms are increased by LPS and DEX, but LPS-dependent Ido1 and Ido2 induction are attenuated by DEX only in the periphery indicating that elevated DO expression and Kyn production within the brain can occur independent of the periphery. These findings demonstrate a plausible interaction between immune activation and glucocorticoids associated with depression.

Short-term and long-term measures of cortisol in saliva and hair in atypical and non-atypical depression

BACKGROUND

Atypical depression may show lowered rather than raised short-term cortisol levels. Atypical major depressive episodes (A-MDE) may also be more closely linked to environmental factors and show overlap with somatic symptom disorders. Hair specimens allow measuring long-term cortisol levels.

METHODS

Twenty-seven A-MDE and 44 NA-MDE patients and 40 matched controls were tested. Measures of hair cortisol concentration [HCC] covering the previous 3 months and short-term cortisol parameters (six saliva specimens to assess the cortisol awakening response [CAR] and total daily cortisol output calculated as the area under the curve [AUCg]) were taken alongside measures of environmental factors and clinical variables.

RESULTS

There were no differences in HCC between the three groups (P = 0.8), and no difference in the CAR (P = 0.95). However, A-MDE showed lowered short-term cortisol output (AUCg) compared to controls (P = 0.04). A-MDE patients also reported a higher number of daily hassles, and higher levels of fatigue and impaired concentration than NA-MDE.

CONCLUSIONS

Normal long-term (HCC) and reduced short-term (AUCg) cortisol levels in A-MDE could suggest a disrupted long-term cortisol rhythm, perhaps affected by environmental factors or by certain symptoms, such as mid-nocturnal insomnia. However, other underlying explanations for these findings should also be investigated in the future.

Elevated fingernail cortisol levels in major depressive episodes

BACKGROUND

The extent to which cortisol levels are elevated in major depressive episodes (MDE), and hence could act as a biomarker of illness, remains unclear. Although patient characteristics may explain some of this variation - for example elevated cortisol being more often found in patients with severe, psychotic or melancholic depression - problems with the methods used to measure cortisol may also have contributed to the inconsistent findings. Fingernails are a novel sample that can be used to assess aggregate cortisol concentrations over a 15-day period, and may provide a more accurate reflection of longer term cortisol level changes in MDE and help clarify this issue. This methodology has not yet been utilised in MDE.

METHODS

Cortisol levels reflecting a period of 15days were measured using fingernails in a group of 26 subjects experiencing a major depressive episode (MDE) and in an age and gender matched group of 45 healthy controls.

RESULTS

Depressed subjects showed significantly higher mean cortisol levels measured in fingernails when compared with control subjects. Higher levels of cortisol were associated with higher depression severity scores, a diagnosis of non-reactive depression, and more prominent melancholic symptoms. Conversely, fatigue was negatively correlated with cortisol levels.

CONCLUSION

There is elevated cortisol in MDE when assessed using an aggregate measure over two weeks.Alterations in fingernail cortisol correlate with key clinical symptoms and subtypes of depression.

Nutraceuticals to promote neuronal plasticity in response to corticosterone-induced stress in human neuroblastoma cells

Objectives: To search for novel compounds that will protect neuronal cells under stressed conditions that may help to restore neuronal plasticity. Methods: A model of corticosterone (CORT)-induced stress in human neuroblastoma cells (SH-SY5Y) was used to compare the efficacy of 6 crude extracts and 10 pure compounds (6 polyphenols, 2 carotenoids, 1 amino acid analogue, and 1 known antidepressant drug) to increase neuronal plasticity and to decrease cytotoxicity. Results: Astaxanthin (among pure compounds) and phlorotannin extract of Fucus vesiculosus (among crude extracts) showed a maximum increase in cell viability in the presence of excess CORT. BDNF-VI mRNA expression in SH-SY5Y cells was significantly improved by pretreatment with quercetine, astaxanthin, curcumin, fisetin, and resveratrol. Among crude extracts, xanthohumol, phlorotannin extract (Ecklonia cava), petroleum ether extract (Nannochloropsis oculata), and phlorotannin extract (F. vesiculosus) showed a significant increase in BDNF-VI mRNA expression. CREB1 mRNA expression was significantly improved by astaxanthin, β-carotene, curcumin, and fluoxetine whereas none of the crude extracts caused significant improvement. As an adjunct of fluoxetine, phlorotannin extract (F. vesiculosus), β-carotene, and xanthohumol have resulted in significant improvement in BDNF-VI mRNA expression and CREB1 mRNA expression was significantly improved by phlorotannin extract (F. vesiculosus). Significant improvement in mature BDNF protein expression by phlorotannin extract (F. vesiculosus) and β-carotene as an adjunct of fluoxetine confirm their potential to promote neuronal plasticity against CORT-induced stress. Discussion: The carotenoids, flavonoids, namely quercetine, curcumin, and low molecular weight phlorotannin-enriched extract of F. vesiculosus may serve as potential neuroprotective agents promoting neuronal plasticity in vitro. Graphical abstract: Cascade of events associated with disturbed homeostatic balance of glucocorticoids and impact of phlorotannin extract (F. vesiculosus) and β-carotene in restoring neuronal plasticity. Abbreviation: TrKB, tropomyosin receptor kinase B; P-ERK, phosphorylated extracellular signal-related kinase; PI3K, phosphatidylinositol 3-kinase; Akt, protein kinase B; Ca++/CaMK, calcium/calmodulin-dependent protein kinase; pCREB, phosphorylated cAMP response element-binding protein; CRE, cAMP response elements, CORT, corticosterone; and BDNF; brain-derived neurotrophic factor.

Shiftwork-Mediated Disruptions of Circadian Rhythms and Sleep Homeostasis Cause Serious Health Problems

Shiftwork became common during the last few decades with the growing demands of human life. Despite the social inactivity and irregularity in habits, working in continuous irregular shifts causes serious health issues including sleep disorders, psychiatric disorders, cancer, and metabolic disorders. These health problems arise due to the disruption in circadian clock system, which is associated with alterations in genetic expressions. Alteration in clock controlling genes further affects genes linked with disorders including major depression disorder, bipolar disorder, phase delay and phase advance sleep syndromes, breast cancer, and colon cancer. A diverse research work is needed focusing on broad spectrum changes caused by jet lag in brain and neuronal system. This review is an attempt to motivate the researchers to conduct advanced studies in this area to identify the risk factors and mechanisms. Its goal is extended to make the shift workers aware about the risks associated with shiftwork.

Neurotrophic, Cytoprotective, and Anti-inflammatory Effects of St. John's Wort Extract on Differentiated Mouse Hippocampal HT-22 Neurons

Introduction: Since ancient times Hypericum perforatum L. named St. John's wort (SJW), has been used in the management of a wide range of applications, including nervous disorders. Development of mood disorders are due to alterations in glutamate metabolism, initiation of inflammatory pathways, and changes of the neuronal plasticity. Previous studies suggest that the glutamatergic system contributes to the pathophysiology of depression. Extracts of SJW have been recommended for the treatment of depression. The aim of the present in vitro study was to evaluate the action of STW3-VI, a special SJW extract in differentiated mouse hippocampal HT-22 neurons. We evaluated the stimulation of neurogenesis, the protective effect against glutamate or N-methyl-D-aspartate receptor induced-excitotoxicity and its anti-inflammatory properties in LPS-activated human macrophages. Results: After 48 h treatment, STW3-VI stimulated the neurite formation by 25% in comparison with the control and showed protective effects against glutamate- or NMDA-induced cytotoxicity by significantly increasing the viability about +25 or +50%. In conjunction with these effects, after pretreatment with STW3-VI, the intracellular reduced glutathione content was significantly 2.3-fold increased compared with the neurons incubated with glutamate alone. Additionally, pre-treatment of human macrophages with STW3-VI showed anti-inflammatory effects after 24 or 48 h concerning inhibition of LPS-induced TNF release by -47.3 and -53.8% (24 h) or -25.0 to -64.8% (48 h). Conclusions: Our data provide new evidence that STW3-VI protects hippocampal cells from NMDA- or glutamate-induced cytotoxicity. Moreover, our results indicate a morphological remodeling by increasing neurite outgrowth and activation of the anti-inflammatory defense by inhibition of the cytokine production in human macrophages after STW3-VI treatment. These protective, neurotrophic and anti-inflammatory properties may be beneficial in the treatment of depressive disorders.

Night Work and the Risk of Depression

BACKGROUND

Working the night shift interferes with the circadian chronobiological rhythm, causing sleep disturbances, fatigue, and diminished wellbeing, and increases the risk of serious disease. The question whether night work increases the risk of depression has not been adequately studied to date.

METHODS

We carried out a systematic, broadly conceived literature search in the PubMed, Scopus, PsycINFO, and PSYNDEX databases and the Medpilot search portal on the topic of nighttime shift work and mental illness.

RESULTS

The search yielded 5682 hits, which were narrowed down by predefined selection criteria to 11 high-quality longitudinal studies on the relationship between nighttime shift work and depressive illness. Only these 11 studies were subjected to further analysis. 3 of 4 studies on nighttime shift work in the health professions (almost exclusively nursing) revealed no association with depression over an observation period of two years. On the other hand, 5 studies on nighttime shift work in occupations outside the health sector, with observation periods of two or more years, yielded evidence of an elevated risk of depression after several years of nighttime shift work, but not in any uniform pattern. A supplementary meta-analysis of 5 of the studies revealed a 42% increase of the risk of depression among persons working the night shift (95% confidence interval [0.92; 2.19]). Psychosocial working conditions that have a negative influence on health partially account for these associations.

CONCLUSION

Although there is evidence that nighttime shift work (at least, in occupations outside the health sector) does increase the risk of depression, this evidence is not strong enough to sustain a general medical recommendation against shift work for employees with depressive conditions. It would seem appropriate to address this question on an individual basis, with strong support from physicians and close attention to the deleterious psychosocial factors associated with shift work.

Neural Signaling of Cortisol, Childhood Emotional Abuse, and Depression-Related Memory Bias

BACKGROUND

Cortisol has potent effects on learning and neuroplasticity, but little is known about its effects on negative memory biases in depression. Animal models show that aversive caregiving alters effects of glucocorticoids (primarily corticosterone in rodents and cortisol in primates) on learning and neuroplasticity into adulthood.

METHODS

We investigated whether history of childhood emotional abuse (EA) moderated effects of cortisol administration (CORT) versus placebo on emotional memory formation in depression. Participants included 75 unmedicated women with varying levels of depression severity and/or EA history. In a double-blind crossover investigation, we used functional magnetic resonance imaging to measure effects of CORT (vs. placebo) on neural function during emotional memory formation.

RESULTS

CORT eliminated the well-known relationship between depression severity and negative memory bias, a finding explained by EA severity. For women with a history of severe EA, CORT reduced depression-related negative memory bias and normalized recall for pleasant stimuli. EA severity also moderated CORT effects on neural function: in women with history of severe EA, CORT increased activation in the supplementary motor area during viewing of unpleasant relative to pleasant pictures. Additionally, supplementary motor area activation predicted reduced negative bias for pictures encoded during CORT.

CONCLUSIONS

These results suggest that increasing cortisol signaling may be neurocognitively beneficial in depressed women with a history of maltreatment. The findings corroborate prior research suggesting that presence or absence of adverse caregiving is etiologically important in depression. These findings suggest potential neurocognitive mechanisms of therapeutics targeting cortisol signaling, which show promise in treating affective disorders.

Fibroblast growth factor 22 is a novel modulator of depression through interleukin-1β

BACKGROUND AND AIMS

Emerging evidence shows that fibroblast growth factor 22 (FGF22) plays a critical role in the etiology of depression. However, the molecular mechanisms of FGF22 are not fully comprehended. Here, the effect of FGF22 in depression and its relationship with interleukin-1β (IL-1β) were investigated in clinical, animal, and cell experiments.

METHODS

Serum from depressive patients was collected, and the levels of FGF22 and IL-1β were analyzed by ELISA. The chronic unpredictable mild stress (CUMS) model was established, and primary hippocampal neuronal cells were cultured to examine changes in FGF22 and IL-1β levels in rat hippocampus.

RESULTS

The results revealed a negative correlation between serum FGF22 levels and serum IL-1β levels. The expression of IL-1β in the CUMS rat hippocampus decreased, and the apoptosis of hippocampal cells improved after the injection of lentiviral vector-mediated FGF22 (LV-FGF22). Further tests in primary hippocampal neuronal cells also showed a reduction in IL-1β and the cell apoptosis rate after treatment with FGF22.

CONCLUSION

In conclusion, the results revealed that FGF22 plays a role in alleviating depression, which may be mediated by reduced expression of IL-1β.

Differential effects of imipramine and CORT118335 (Glucocorticoid receptor modulator/mineralocorticoid receptor antagonist) on brain-endocrine stress responses and depression-like behavior in female rats

Depression is commonly associated with hypothalamic-pituitary adrenal (HPA) axis dysfunction that primarily manifests as aberrant glucocorticoid secretion. Glucocorticoids act on Type I mineralocorticoid (MR) and Type II glucocorticoid receptors (GR) to modulate mood and endocrine responses. Successful antidepressant treatment normalizes HPA axis function, in part due to modulatory effects on MR and GR in cortico-limbic structures. Although women are twice as likely to suffer from depression, little is known about how antidepressants modulate brain, endocrine, and behavioral stress responses in females. Here, we assessed the impact of CORT118335 (GR modulator/MR antagonist) and imipramine (tricyclic antidepressant) on neuroendocrine and behavioral responses to restraint or forced swim stress (FST) in female rats (n=10-12/group). Increased immobility CORT118335 in the FST is purported to reflect passive coping or depression-like behavior. CORT118335 dampened adrenocorticotropic hormone (ACTH) and corticosterone responses to the FST, but did not affect immobility. Imipramine suppressed ACTH, but had minimal effects on corticosterone responses to FST. Despite these marginal effects, imipramine decreased immobility, suggesting antidepressant efficacy. In an effort to link brain-endocrine responses with behavior, c-Fos was assessed in HPA axis and mood modulatory regions in response to the FST. CORT118335 upregulated c-Fos expression in the paraventricular nucleus of the hypothalamus. Imipramine decreased c-Fos in the basolateral amygdala and hippocampus (CA1 and CA3), but increased c-Fos in the central amygdala. These data suggest the antidepressant-like (e.g., active coping) properties of imipramine may be due to widespread effects on cortico-limbic circuits that regulate emotional and cognitive processes.

HPA axis reactivity to pharmacologic and psychological stressors in euthymic women with histories of postpartum versus major depression

It is unclear whether women with a history of postpartum depression (PPD) have residual, abnormal hypothalamic-pituitary-adrenal (HPA) axis reactivity, as has been reported in major depression (MDD). Further unclear is whether the abnormalities in HPA axis reactivity associated with MDD represent a stable, underlying predisposition or a state-dependent phenomenon. This study sought the following: (1) to determine if euthymic postpartum women with a history of depression have an abnormal HPA axis reactivity to pharmacologic and psychological challenges and (2) to compare HPA reactivity in women with histories of PPD versus MDD. As a secondary objective, we wanted to determine the influence of trauma history on HPA axis function. Forty-five parous (12-24 months postpartum), euthymic women with history of MDD (n = 15), PPD (n = 15), and controls (n = 15) completed pharmacologic (dexamethasone/corticotropin-releasing hormone (CRH) test [DEX/CRH]) and psychological (Trier social stress test [TSST]) challenges during the luteal phase. Outcome measures were cortisol and adrenocorticotropic hormone (ACTH) response after DEX/CRH, and blood pressure, heart rate, epinephrine, norepinephrine, and cortisol response during the TSST. All groups had robust cortisol and ACTH response to DEX/CRH and cortisol response to TSST. Groups did not differ significantly in cortisol or ACTH response to DEX/CRH or in blood pressure, heart rate, epinephrine, norepinephrine, or cortisol response to TSST. Cortisol/ACTH ratio did not differ significantly between groups. Trauma history was associated with decreased cortisol response to DEX/CRH in women with histories of MDD, which was not significant after correction (F _8,125, p = 0.02, Greenhouse-Geisser corrected p = 0.11). Currently euthymic women with histories of MDD or PPD did not demonstrate residual abnormal stress responsivity following administration of either a pharmacologic or psychological stressor.

Mechanisms of Brain Glucocorticoid Resistance in Stress-Induced Psychopathologies

Exposure to stress activates the hypothalamic-pituitary-adrenal axis and leads to increased levels of glucocorticoid (GC) hormones. Prolonged elevation of GC levels causes neuronal dysfunction, decreases the density of synapses, and impairs neuronal plasticity. Decreased sensitivity to glucocorticoids (glucocorticoid resistance) that develops as a result of chronic stress is one of the characteristic features of stress-induced psychopathologies. In this article, we reviewed the published data on proposed molecular mechanisms that contribute to the development of glucocorticoid resistance in brain, including changes in the expression of the glucocorticoid receptor (GR) gene, biosynthesis of GR isoforms, and GR posttranslational modifications. We also present data on alterations in the expression of the FKBP5 gene encoding the main component of cell ultra-short negative feedback loop of GC signaling regulation. Recent discoveries on stress- and GR-induced changes in epigenetic modification patterns as well as normalizing action of antidepressants are discussed. GR and FKBP5 gene polymorphisms associated with stress-induced psychopathologies are described, and their role in glucocorticoid resistance is discussed.