Depression research: where are we now?

Frontal Alpha Asymmetry and Its Modulation by Monoaminergic Neurotransmitters in Depression

Frontal alpha asymmetry (FAA) is an electroencephalography (EEG) measure that quantifies trait-like left versus right hemisphere lateralization in alpha power. Increased FAA indicates relatively greater left than right frontal cortex activation and is associated with enhanced reward-related approach behaviors rather than avoidance or withdrawal. Studies dating back several decades have often suggested that having greater FAA supports enhanced positive affect and protection against major depressive disorder (MDD), whereas having greater right frontal activation (i.e., reduced FAA) is associated with negative affect and risk for MDD. While this hypothesis is widely known, a number of other studies instead have found increased FAA in MDD, or evidence that either leftward or rightward bias in FAA is associated with depression. Here we briefly review the literature on leftward or rightward lateralization in FAA in MDD, and find much evidence that MDD is not always characterized by reduced FAA. We also review the limited literature on FAA and monoaminergic neurotransmitter systems, including pharmacologic agents that act on them. Studies of serotonin in particular provide genetic and pharmacologic evidence for modulation of FAA, where some of these data may suggest that serotonin reduces FAA. In a synthesis of the collective literature on FAA and the monoamines, we suggest that serotonin and norepinephrine may differentially affect FAA, with serotonin tending to promote right frontal activation and norepinephrine biased toward left frontal activation. These putative differences in frontal lateralization may influence MDD phenotypes or potential subtypes of the disorder, and suggest pharmacologic treatment strategies.

Fluorescent Probes for Disease Diagnosis

The identification and detection of disease-related biomarkers is essential for early clinical diagnosis, evaluating disease progression, and for the development of therapeutics. Possessing the advantages of high sensitivity and selectivity, fluorescent probes have become effective tools for monitoring disease-related active molecules at the cellular level and in vivo. In this review, we describe current fluorescent probes designed for the detection and quantification of key bioactive molecules associated with common diseases, such as organ damage, inflammation, cancers, cardiovascular diseases, and brain disorders. We emphasize the strategies behind the design of fluorescent probes capable of disease biomarker detection and diagnosis and cover some aspects of combined diagnostic/therapeutic strategies based on regulating disease-related molecules. This review concludes with a discussion of the challenges and outlook for fluorescent probes, highlighting future avenues of research that should enable these probes to achieve accurate detection and identification of disease-related biomarkers for biomedical research and clinical applications.

Role of Glial Cells in Neuronal Function, Mood Disorders, and Drug Addiction

Mood disorders and substance use disorder (SUD) are of immense medical and social concern. Although significant progress on neuronal involvement in mood and reward circuitries has been achieved, it is only relatively recently that the role of glia in these disorders has attracted attention. Detailed understanding of the glial functions in these devastating diseases could offer novel interventions. Here, following a brief review of circuitries involved in mood regulation and reward perception, the specific contributions of neurotrophic factors, neuroinflammation, and gut microbiota to these diseases are highlighted. In this context, the role of specific glial cells (e.g., microglia, astroglia, oligodendrocytes, and synantocytes) on phenotypic manifestation of mood disorders or SUD are emphasized. In addition, use of this knowledge in the potential development of novel therapeutics is touched upon.

Identification and Evaluation of Olive Phenolics in the Context of Amine Oxidase Enzyme Inhibition and Depression: In Silico Modelling and In Vitro Validation

The Mediterranean diet well known for its beneficial health effects, including mood enhancement, is characterised by the relatively high consumption of extra virgin olive oil (EVOO), which is rich in bioactive phenolic compounds. Over 200 phenolic compounds have been associated with Olea europaea, and of these, only a relatively small fraction have been characterised. Utilising the OliveNetTM library, phenolic compounds were investigated as potential inhibitors of the epigenetic modifier lysine-specific demethylase 1 (LSD1). Furthermore, the compounds were screened for inhibition of the structurally similar monoamine oxidases (MAOs) which are directly implicated in the pathophysiology of depression. Molecular docking highlighted that olive phenolics interact with the active site of LSD1 and MAOs. Protein-peptide docking was also performed to evaluate the interaction of the histone H3 peptide with LSD1, in the presence of ligands bound to the substrate-binding cavity. To validate the in silico studies, the inhibitory activity of phenolic compounds was compared to the clinically approved inhibitor tranylcypromine. Our findings indicate that olive phenolics inhibit LSD1 and the MAOs in vitro. Using a cell culture model system with corticosteroid-stimulated human BJ fibroblast cells, the results demonstrate the attenuation of dexamethasone- and hydrocortisone-induced MAO activity by phenolic compounds. The findings were further corroborated using human embryonic stem cell (hESC)-derived neurons stimulated with all-trans retinoic acid. Overall, the results indicate the inhibition of flavin adenine dinucleotide (FAD)-dependent amine oxidases by olive phenolics. More generally, our findings further support at least a partial mechanism accounting for the antidepressant effects associated with EVOO and the Mediterranean diet.

Vitamin B12 and homocysteine in patients with major depressive disorder

Background

Alterations in the level of neurotransmitters are evident in patients with major depressive disorder (MDD). Vitamin B12 mediates the synthesis of neurotransmitters, and hence, vitamin B12 deficiency could be associated with depression.

Aims and Objectives

To assess the levels of serum vitamin B12, homocysteine (Hcy), and haematological profiles in patients of MDD.

Materials and Methods

Fifty-nine patients with MDD were recruited based on ICD-10 criteria. Severity of depression was assessed by HAM-D scale. Vitamin B12, Hcy levels, and haematological profiles were analysed.

Results

Vitamin B12 was deficient or depleted in all patients with MDD. The median level of vitamin B12 in serum was 164.2 pg./ml and significantly lower in patients with severe MDD. The mean value of Hcy was 18.34 μmol/L, which was high compared to the normal reference range. The red cell distribution width (RDW-CV) varied significantly between the three groups of MDD patients. Patients consuming non-vegetarian food had a significantly higher median value of serum vitamin B12.

Conclusion

Vitamin B12 deficiency is found in patients with MDD and varies inversely with severity of MDD. Hcy is found to be higher in patients with MDD. The manifestation of depressive symptoms precedes the more commonly known haematological manifestations of vitamin B12 deficiency in this study.

New perspective on sustained antidepressant effect: focus on neurexins regulating synaptic plasticity

Depression is highly prevalent globally, however, currently available medications face challenges such as low response rates and short duration of efficacy. Additionally, depression mostly accompany other psychiatric disorders, further progressing to major depressive disorder without long-term effective management. Thus, sustained antidepressant strategies are urgently needed. Recently, ketamine and psilocybin gained attention as potential sustained antidepressants. Review of recent studies highlights that synaptic plasticity changes as key events of downstream long-lasting changes in sustained antidepressant effect. This underscores the significance of synaptic plasticity in sustained antidepressant effect. Moreover, neurexins, key molecules involved in the regulation of synaptic plasticity, act as critical links between synaptic plasticity and sustained antidepressant effects, involving mechanisms including protein level, selective splicing, epigenetics, astrocytes, positional redistribution and protein structure. Based on the regulation of synaptic plasticity by neurexins, several drugs with potential for sustained antidepressant effect are also discussed. Focusing on neurexins in regulating synaptic plasticity promises much for further understanding underlying mechanisms of sustained antidepressant and the next step in new drug development. This research represents a highly promising future research direction.

Affective disorders and the loudness dependence of the auditory evoked potential: Serotonin and beyond

Identifying additional noninvasive biomarkers for affective disorders, such as unipolar major depressive disorder (MDD) and bipolar disorder (BD), could aid in the diagnosis and treatment of these prevalent and debilitating neuropsychiatric conditions. One such candidate biomarker is the loudness dependence of the auditory evoked potential (LDAEP), an event-related potential that measures responsiveness of the auditory cortex to different intensities of sound. The LDAEP has been associated with MDD and BD, including therapeutic response to particular classes of antidepressant drugs, while also correlating with several other neuropsychiatric disorders. It has been suggested that increased values of the LDAEP indicate low central serotonergic neurotransmission, further implicating this EEG measure in depression. Here, we briefly review the literature on the LDAEP in affective disorders, including its association with serotonergic signaling, as well as with that of other neurotransmitters such as dopamine. We summarize key findings on the LDAEP and the genetics of these neurotransmitters, as well as prediction of response to particular classes of antidepressants in MDD, including SSRIs versus noradrenergic agents. The possible relationship between this EEG measure and suicidality is addressed. We also briefly analyze acute pharmacologic studies of serotonin and/or dopamine precursor depletion and the LDAEP. In conclusion, the existing literature suggests that serotonin and norepinephrine may modulate the LDAEP in an opposing manner, and that this event-related marker may be of use in predicting response to chronic treatment with particular pharmacologic agents in the context of affective disorders, such as MDD and BD, including in the presence of suicidality.

Interplay of G-proteins and Serotonin in the Neuroimmunoinflammatory Model of Chronic Stress and Depression: A Narrative Review

INTRODUCTION

This narrative review addresses the clinical challenges in stress-related disorders such as depression, focusing on the interplay between neuron-specific and pro-inflammatory mechanisms at the cellular, cerebral, and systemic levels.

OBJECTIVE

We aim to elucidate the molecular mechanisms linking chronic psychological stress with low-grade neuroinflammation in key brain regions, particularly focusing on the roles of G proteins and serotonin (5-HT) receptors.

METHODS

This comprehensive review of the literature employs systematic, narrative, and scoping review methodologies, combined with systemic approaches to general pathology. It synthesizes current research on shared signaling pathways involved in stress responses and neuroinflammation, including calcium-dependent mechanisms, mitogen-activated protein kinases, and key transcription factors like NF-κB and p53. The review also focuses on the role of G protein-coupled neurotransmitter receptors (GPCRs) in immune and pro-inflammatory responses, with a detailed analysis of how 13 of 14 types of human 5-HT receptors contribute to depression and neuroinflammation.

RESULTS

The review reveals a complex interaction between neurotransmitter signals and immunoinflammatory responses in stress-related pathologies. It highlights the role of GPCRs and canonical inflammatory mediators in influencing both pathological and physiological processes in nervous tissue.

CONCLUSION

The proposed Neuroimmunoinflammatory Stress Model (NIIS Model) suggests that proinflammatory signaling pathways, mediated by metabotropic and ionotropic neurotransmitter receptors, are crucial for maintaining neuronal homeostasis. Chronic mental stress can disrupt this balance, leading to increased pro-inflammatory states in the brain and contributing to neuropsychiatric and psychosomatic disorders, including depression. This model integrates traditional theories on depression pathogenesis, offering a comprehensive understanding of the multifaceted nature of the condition.

Association between rare earth elements and depression: Evidence from pilot mice model of chronic unpredictable mild stress-induced depression and human studies of major depressive disorder

The etiology of Major Depressive Disorder (MDD) has been associated with levels of trace elements in the human body. The source of trace elements in the human body may be rare earth elements (REEs). Our study aimed to identify the potential relationship between t REEs in blood and brain samples and depression from two paths: animal experiments and population studies. In the animal experiments, 35 adult Sprague-Dawley rats were randomly allocated to the control group (n = 14) and treatment group (n = 21), which received the chronic unpredictable mild stress (CUMS) procedure for four weeks and further categorized into the sensitive group (n = 9) and resilient group (n = 12) by sucrose water preference test. Then, all rats were executed to obtain serum and brain tissue samples. We also recruited 197 participants and divided them into the major depressive disorder (MDD) group (n = 100) and the control group (n = 97) then serum samples were collected for REEs detection. Our finding reported that significant differences were found in the levels of La and Ce in blood samples from different groups in the CUMS rat model (sensitive group < resilient group < control group) (all p < 0.05), with similar patterns for other elements (Pr, Nd, and Y) (but p > 0.5). No significant inter-group difference was reported in rat brain tissue samples. After adjusting for demographic variables, we found that the concentrations of all five REEs (La, Ce, Pr, Nd, Y) were lower in depression group than in control group (all p < 0.01). The current conjoint animal and human data supported appropriate levels of REEs have a certain protective effect on body health. These results may be attributed to Hormesis effects. Whether the possible favorable effects of REEs on improving symptoms of depression or can be applied to drug development remains to be further investigated.

Investigating the potential effects of α-synuclein aggregation on susceptibility to chronic stress in a mouse Parkinson's disease model

BACKGROUND

Parkinson's disease (PD) is a motor disorder characterized by the degeneration of dopaminergic neurons, putatively due to the accumulation of α-synuclein (α-syn) in Lewy bodies (LBs) in Substantia Nigra. PD is also associated with the formation of LBs in brain areas responsible for emotional and cognitive regulation such as the amygdala and prefrontal cortex, and concurrent depression prevalence in PD patients. The exact link between dopaminergic cell loss, α-syn aggregation, depression, and stress, a major depression risk factor, is unclear. Therefore, we aimed to explore the interplay between sensitivity to chronic stress and α-syn aggregation.

METHODS

Bilateral injections of α-syn preformed fibrils (PFFs) into the striatum of C57Bl/6 J mice were used to induce α-syn aggregation. Three months after injections, animals were exposed to chronic social defeat stress.

RESULTS

α-syn aggregation did not affect stress susceptibility but independently caused increased locomotor activity in the open field test, reduced anxiety in the light-dark box test, and increased active time in the tail suspension test. Ex vivo analysis revealed modest dopaminergic neuron loss in the substantia nigra and reduced dopaminergic innervation in the dorsal striatum in PFFs injected groups. α-Syn aggregates were prominent in the amygdala, prefrontal cortex, and substantia nigra, with minimal α-syn aggregation in the raphe nuclei and locus coeruleus.

CONCLUSIONS

Progressive bilateral α-syn aggregation might lead to compensatory activity increase and alterations in emotionally regulated behavior, without affecting stress susceptibility. Understanding how α-syn aggregation and degeneration in specific brain structures contribute to depression and anxiety in PD patients requires further investigation.

EPO prevents neuroinflammation and relieves depression via JAK/STAT signaling

AIMS

Erythropoietin (EPO) is a glycoprotein cytokine that exerts therapeutic potential on neurological disorders by promoting neurogenesis and angiogenesis. However, its role as an antidepressant via anti-inflammatory axes is poorly explored. Furthermore, chronic inflammation can induce neuroinflammation, concurrent with depressive-like behaviors that anti-inflammatory and antidepressant agents could avert. Here, we aimed to elucidate the antidepressant potential of Erythropoietin (EPO) in the LPS-induced depression model.

MAIN METHODS

For in vivo analysis, mice were treated with LPS (2 mg/kg BW), Erythropoietin (EPO) (5000 U/kg/day), (Ruxolitinib,15 mg/kg), and K252a (25 μg/kg). Depressive-like behaviors were confirmed via behavior tests, including OFT, FST, SPT, and TST. Cytokines were measured via ELISA, while IBA-1/GFAP expression was determined by immunofluorescence. Further, the desired gene expression was measured by immunoblotting. For in vitro analysis, BV2 and N2a cell lines were cultured, treated with LPS, EPO, Ruxolitinib, and K252a, collected, and analyzed.

KEY FINDINGS

LPS treatment significantly induced neuroinflammation accompanied by depression-like behaviors in mice. However, EPO treatment rescued LPS-induced changes by averting cytokine production, secretion, and glial cell activation and reducing depressive-like behaviors in mice. Surprisingly, EPO treatment ameliorated LPS-induced JAK2/STAT5 signaling impairment, as validated by JAK2-antagonism. Furthermore, synaptic and dendritic spine defects and BNDF/TrkB signaling upon LPS administration could be prevented by EPO treatment.

SIGNIFICANCE

EPO could act as an antidepressant via its anti-inflammatory potential by regulating JAK2/STAT5 signaling.

Moving from serotonin to serotonin-norepinephrine enhancement with increasing venlafaxine dose: clinical implications and strategies for a successful outcome in major depressive disorder

INTRODUCTION

Mental health disorders, especially depressive and anxiety disorders, are associated with substantial health-related burden. While the second-generation antidepressants are widely accepted as first-line pharmacological treatment for major depressive disorder (MDD), patient response to such treatment is variable, with more than half failing to achieve complete remission, and residual symptoms are frequently present.

AREAS COVERED

Here, the pharmacodynamics of venlafaxine XR are reviewed in relation to its role as both a selective serotonin reuptake inhibitor (SSRI) and a serotonin-norepinephrine-reuptake inhibitor (SNRI), and we look at how these pharmacodynamic properties can be harnessed to guide clinical practice, asking the question 'is it possible to develop a symptom-cluster-based approach to the treatment of MDD with comorbid anxiety utilizing venlafaxine XR?.' Additionally, three illustrative clinical cases provide practical examples of the utility of venlafaxine-XR in real-world clinical practice. The place of venlafaxine XR in managing fatigue/low energy, a frequent residual symptom in MDD, is explored using pooled data from clinical trials of venlafaxine XR.

EXPERT OPINION

Venlafaxine XR should be considered as a first-line treatment for MDD with or without comorbid anxiety, and there are clear pharmacodynamic signals supporting a symptom cluster-based treatment paradigm for venlafaxine XR.

Adaptogenic property of Asparagus racemosus: Future trends and prospects

Major depressive disorder (MDD) is a multimodal neuropsychiatric and neurodegenerative illness characterized by anhedonia, continued melancholy, dysfunctional circadian rhythm and many other behavioral infirmities. Depression is also associated with somatic ailments such as cardiometabolic diseases. The existing and upcoming hypotheses have succeeded in explaining the pathophysiology of depression. Only a few of the most validated theories, such as hyperactivity of the HPA axis, activated inflammatory-immune response, and monoaminergic and GABAergic deficit hypotheses, have been discussed in this review. So, an effective and safer alternative approach beyond symptomatic relief has been desired. Therefore, botanical products have steadily been probed to strengthen the modern medicinal system as a promising medicament. In this line, Asparagus racemosus Willd. belongs to Asparagaceace family is the well-documented adaptogen cited in the ancient texts namely, Ayurvedic, Greek, and Chinese medicine system. The whole plant possesses pleiotropic therapeutic activity, antioxidant, anti-inflammatory, immunomodulatory, neuroprotective, nootropic, antidepressant, etc., without showing any remarkable side effects. The literature review has also suggested that A. racemosus administration at varied levels alleviates depression by modulating the HPA axis, increasing BDNF levels, and monoaminergic and GABAergic neurotransmission. Alongside, spikes the level of antioxidant enzymes, SOD, GSH peroxidase, GSH, and catalase in distinct brain regions (i.e., hippocampus, prefrontal cortex, amygdala, and hypothalamus) and promote neurogenesis and neuroplasticity. Thus, it could be a new generation antidepressant that provides relief from both behavioral and somatic illness. The review first describes the plant characteristics, then discusses the hypotheses associated with the pathogenesis of depression, and gives an insight into A. racemosus antidepressant properties and the underlying mechanism.

The Missing Piece? A Case for Microglia's Prominent Role in the Therapeutic Action of Anesthetics, Ketamine, and Psychedelics

There is much excitement surrounding recent research of promising, mechanistically novel psychotherapeutics - psychedelic, anesthetic, and dissociative agents - as they have demonstrated surprising efficacy in treating central nervous system (CNS) disorders, such as mood disorders and addiction. However, the mechanisms by which these drugs provide such profound psychological benefits are still to be fully elucidated. Microglia, the CNS's resident innate immune cells, are emerging as a cellular target for psychiatric disorders because of their critical role in regulating neuroplasticity and the inflammatory environment of the brain. The following paper is a review of recent literature surrounding these neuropharmacological therapies and their demonstrated or hypothesized interactions with microglia. Through investigating the mechanism of action of psychedelics, such as psilocybin and lysergic acid diethylamide, ketamine, and propofol, we demonstrate a largely under-investigated role for microglia in much of the emerging research surrounding these pharmacological agents. Among others, we detail sigma-1 receptors, serotonergic and γ-aminobutyric acid signalling, and tryptophan metabolism as pathways through which these agents modulate microglial phagocytic activity and inflammatory mediator release, inducing their therapeutic effects. The current review includes a discussion on future directions in the field of microglial pharmacology and covers bidirectional implications of microglia and these novel pharmacological agents in aging and age-related disease, glial cell heterogeneity, and state-of-the-art methodologies in microglial research.

Inhibition of Microglial GSK3β Activity Is Common to Different Kinds of Antidepressants: A Proposal for an In Vitro Screen to Detect Novel Antidepressant Principles

Depression is a major public health concern. Unfortunately, the present antidepressants often are insufficiently effective, whilst the discovery of more effective antidepressants has been extremely sluggish. The objective of this review was to combine the literature on depression with the pharmacology of antidepressant compounds, in order to formulate a conceivable pathophysiological process, allowing proposals how to accelerate the discovery process. Risk factors for depression initiate an infection-like inflammation in the brain that involves activation microglial Toll-like receptors and glycogen synthase kinase-3β (GSK3β). GSK3β activity alters the balance between two competing transcription factors, the pro-inflammatory/pro-oxidative transcription factor NFκB and the neuroprotective, anti-inflammatory and anti-oxidative transcription factor NRF2. The antidepressant activity of tricyclic antidepressants is assumed to involve activation of GS-coupled microglial receptors, raising intracellular cAMP levels and activation of protein kinase A (PKA). PKA and similar kinases inhibit the enzyme activity of GSK3β. Experimental antidepressant principles, including cannabinoid receptor-2 activation, opioid μ receptor agonists, 5HT2 agonists, valproate, ketamine and electrical stimulation of the Vagus nerve, all activate microglial pathways that result in GSK3β-inhibition. An in vitro screen for NRF2-activation in microglial cells with TLR-activated GSK3β activity, might therefore lead to the detection of totally novel antidepressant principles with, hopefully, an improved therapeutic efficacy.

Heterogeneity in major depressive disorder: The need for biomarker-based personalized treatments

Major Depressive Disorder (MDD) or depression is a pathological mental condition affecting millions of people worldwide. Identification of objective biological markers of depression can provide for a better diagnostic and intervention criteria; ultimately aiding to reduce its socioeconomic health burden. This review provides a comprehensive insight into the major biomarker candidates that have been implicated in depression neurobiology. The key biomarker categories are covered across all the "omics" levels. At the epigenomic level, DNA-methylation, non-coding RNA and histone-modifications have been discussed in relation to depression. The proteomics system shows great promise with inflammatory markers as well as growth factors and neurobiological alterations within the endocannabinoid system. Characteristic lipids implicated in depression together with the endocrine system are reviewed under the metabolomics section. The chapter also examines the novel biomarkers for depression that have been proposed by studies in the microbiome. Depression affects individuals differentially and explicit biomarkers identified by robust research criteria may pave the way for better diagnosis, intervention, treatment, and prediction of treatment response.

Unemployment and hair cortisol as a biomarker of chronic stress

Unemployment is widely considered an important chronic stressor. Using longitudinal data of initially employed German jobseekers, the present study examines whether unemployment is related to changes in hair cortisol concentration (HCC), a reliable biomarker for chronic stress. The results indicate that HCC is the highest initially when individuals are insecurely employed and decreases as people gain certainty about whether they enter unemployment or not. We find no effects when comparing the average changes in HCC between individuals who entered unemployment to those of continuously employed individuals. However, medium-term unemployment was associated with a stronger mean increase in HCC if re-employment expectations were low compared to when re-employment expectations were high. Taken together, our results support two key conclusions. First, experiencing the uncertainty of looming unemployment is associated with more pronounced cortisol secretion than unemployment itself. Second, whether working or being unemployed is associated with higher HCC is highly context-dependent, with poor re-employment prospects during unemployment being a key predictor of increased HCC. Overall, our study provides further evidence that the physiological stress system is especially sensitive to uncontrollable situations and unfamiliar challenge.

Running from Stress: Neurobiological Mechanisms of Exercise-Induced Stress Resilience

Chronic stress, even stress of a moderate intensity related to daily life, is widely acknowledged to be a predisposing or precipitating factor in neuropsychiatric diseases. There is a clear relationship between disturbances induced by stressful stimuli, especially long-lasting stimuli, and cognitive deficits in rodent models of affective disorders. Regular physical activity has a positive effect on the central nervous system (CNS) functions, contributes to an improvement in mood and of cognitive abilities (including memory and learning), and is correlated with an increase in the expression of the neurotrophic factors and markers of synaptic plasticity as well as a reduction in the inflammatory factors. Studies published so far show that the energy challenge caused by physical exercise can affect the CNS by improving cellular bioenergetics, stimulating the processes responsible for the removal of damaged organelles and molecules, and attenuating inflammation processes. Regular physical activity brings another important benefit: increased stress robustness. The evidence from animal studies is that a sedentary lifestyle is associated with stress vulnerability, whereas a physically active lifestyle is associated with stress resilience. Here, we have performed a comprehensive PubMed Search Strategy for accomplishing an exhaustive literature review. In this review, we discuss the findings from experimental studies on the molecular and neurobiological mechanisms underlying the impact of exercise on brain resilience. A thorough understanding of the mechanisms underlying the neuroprotective potential of preconditioning exercise and of the role of exercise in stress resilience, among other things, may open further options for prevention and therapy in the treatment of CNS diseases.

Stimulant use in suicides: A systematic review

Suicide remains a global public health concern and the increased supply and use of synthetic stimulants globally may have implications for the burden of suicides attributable to substance use. This systematic review investigated any potential associations of stimulant use detected in post-mortem biological specimens and suicides. We conducted a systematic review and narrative synthesis (CRD42021237966). Medline, EMBASE, TOXLINE, and Scopus databases were searched for terms related to forensic toxicology, post-mortem toxicology, suicide and stimulants. The primary outcome was to estimate the prevalence of stimulant use in suicides. There were 26 studies whichcontributed to prevalence measures; in studies reporting at the individual compound level, suicides involved cocaine (0.1-23%), caffeine (3.2-22%), 3,4-methylenedioxymethamphetamine (0.1-17%), amphetamine (0.2-9.3%), methamphetamine (3.1-7%), and phentermine (0.9-1%). Overall, stimulant use in suicides was over-represented compared to estimates of stimulant use in the general population and has increased over time. Thirteen case reports used to contextualise suicides involving stimulants found no examples of cocaine or methamphetamine mono-intoxication of suicidal intent. This suggests mechanisms other than acute toxicity involved in stimulant-associated suicide. Future research by in-depth psychological autopsies of suicides involving stimulants, in combination with segmental hair analysis to determine the chronicity of stimulant exposure, may contribute to a better understanding of the burden of suicide attributable to stimulant use.

The Athlete’s Paradox: Adaptable Depression

We proposed that an athlete’s depressive symptoms may be different from the general population in etiology if considered from the context of a depressive disorder. By shifting focus from a limited notion of symptoms onto a comprehensive model of depression, the full scope of the phenomenon becomes clearer. This paper investigated the relationship between neurotransmitters and allostatic load to explain the incidence of depression among elite athletes. This literature review extensively analyzed exercise-induced neurohormonal imbalance resulting in depressive states among athletes. The research revealed that 5-HTTLPR polymorphism, brain-derived neurotrophic factor (BDNF), extensive psychological demands, social stigma, and overtraining syndrome (OTS) may all contribute to a unique version of depression. The research revealed that the biological standards of athletes differ from those of non-athletes, to the point that the new model may be useful, thereby introducing the new term “Adaptable Depression (AD)” to the literature. This framework suggests a new direction for future research to precisely measure the neurotransmitter-related brain changes that result in “Adaptable Depression” in athletes and to establish a better understanding of the depressive tipping point.

Ketamine for resistant depression: a scoping review

Ketamine is a fast-acting anesthetic with hypnotic properties. Moreover, could potentially improve affective symptoms in patients with refractory depressive disorder. Objective. explore the scientific literature available until December 10, 2021, about the efficacy and safety of ketamine in patients with treatment-refractory major depressive disorder. Material and methods. Scoping review that included PubMed and Scopus. Records of clinical trials and publications with empirical data in English and Spanish were included.

Immunostimulant and Antidepressant Effect of Natural Compounds in the Management of Covid-19 Symptoms

In recent years, the use of natural compounds as adjuvant treatments and alternatives to traditional pharmacological therapies has become increasingly popular. These compounds have a wide range of biological effects, such as: antioxidant, anti-aging, hypocholesterolizing, hypoglycemic, antitumoral, antidepressant, anxiolytic activity, etc. Almost all of these compounds are easily available and are contained in different foods. At the end of 2019 the Coronavirus SARS-CoV-2 appeared in China and quickly spread throughout the world, causing a pandemic. The most common symptoms of this infection are dry cough, fever, dyspnea, and in severe cases bilateral interstitial pneumonia, with consequences that can lead to death. The nations, in trying to prevent the spread of infection, have imposed social distancing and lockdown measures on their citizens. This had a strong psychological-social impact, leading to phobic, anxious and depressive states. Pharmacological therapy could be accompanied by treatment with several natural compounds, such as vitamins, baicalein, zinc and essential oils. These compounds possess marked immunostimulant activity, strengthening the immune response and mitigating interactions between the virus and the host cell. They also have an antidepressant effect, acting on certain neurotransmitters.

Iptakalim alleviates synaptic damages via targeting mitochondrial ATP-sensitive potassium channel in depression

Synaptic plasticity damages play a crucial role in the onset and development of depression, especially in the hippocampus, which is more susceptible to stress and the most frequently studied brain region in depression. And, mitochondria have a major function in executing the complex processes of neurotransmission and plasticity. We have previously demonstrated that Iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could improve the depressive-like behavior in mice. But the underlying mechanisms are not well understood. The present study demonstrated that Ipt reversed depressive-like phenotype in vivo (chronic mild stress-induced mice model of depression) and in vitro (corticosterone-induced cellular model). Further study showed that Ipt could upregulate the synaptic-related proteins postsynaptic density 95 (PSD 95) and synaptophysin (SYN), and alleviated the synaptic structure damage. Moreover, Ipt could reverse the abnormal mitochondrial fission and fusion, as well as the reduced mitochondrial ATP production and collapse of mitochondrial membrane potential in depressive models. Knocking down the mitochondrial ATP-sensitive potassium (Mito-KATP) channel subunit MitoK partly blocked the above effects of Ipt. Therefore, our results reveal that Ipt can alleviate the abnormal mitochondrial dynamics and function depending on MitoK, contributing to improve synaptic plasticity and exert antidepressive effects. These findings provide a candidate compound and a novel target for antidepressive therapy.

The kynurenine pathway in major depression: What we know and where to next

Major depression is a serious psychiatric disorder, occurring in up to 20 % of the population. Despite its devastating burden, the neurobiological changes associated with depression are not fully understood. A growing body of evidence suggests the kynurenine pathway is implicated in the pathophysiology of depression. In this review, we bring together the literature examining elements of the kynurenine pathway in depression and explore the implications for the pathophysiology and treatment of depression, while highlighting the gaps in the current knowledge. Current research indicates an increased potential for neurotoxic activity of the kynurenine pathway in peripheral blood samples but an increased activation of the putative neuroprotective arm in some brain regions in depression. The disconnect between these findings requires further investigation, with a greater research effort on elucidating the central effects of the kynurenine pathway in driving depression symptomology. Research investigating the benefits of targeting the kynurenine pathway centred on human brain findings and the heterogenous subtypes of depression will help guide the identification of effective drug targets in depression.

Abnormal expression of miR-135a in patients with depression and its possible involvement in the pathogenesis of the condition

At present, due to the increasing pressures on society and the stress of everyday living, the number of individuals suffering from depression has increased. Therefore, the treatment of depression has also received increasing attention. MicroRNA (miRNA/miR)-135a is a well-studied miRNA. It has been reported that miR-135a is significantly downregulated in patients with depression and may be a potential marker for the diagnosis of the condition. However, the specific mechanisms of action of miR-135a in patients with depression remain unclear. In the present study, it was found that miR-135a was downregulated in patients with depression, and in a mouse model of depression. The effects of miR-135a on depression-related symptoms in mice were then explored. In the mice with chronic unpredictable mild stress (CUMS) that were treated with miR-135a for 3 weeks, a significantly reduced level of weight gain was observed in comparison with the control group. In addition, treatment with miR-135a mimic significantly increased sucrose preference in the sucrose preference test in the mice, and reduced the immobility time in the forced swimming test and tail suspension test. Treatment with miR-135a mimic also inhibited CUMS-induced hippocampal cell apoptosis. Furthermore, treatment with miR-135a mimic and fluoxetine significantly reduced the CUMS-induced increase in the expression levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in the hippocampus of the mice. Subsequently, reverse transcription-quantitative polymerase chain reaction and western blot analysis revealed that treatment with miR-135a mimic significantly inhibited the expression of Toll-like receptor 4 in the mouse hippocampus. In conclusion, the findings of the present study indicate that miR-135a may be a novel potential target for the treatment of depression.

Peripheral Markers of Depression

Major Depressive Disorder (MDD) is a leading cause of disability worldwide, creating a high medical and socioeconomic burden. There is a growing interest in the biological underpinnings of depression, which are reflected by altered levels of biological markers. Among others, enhanced inflammation has been reported in MDD, as reflected by increased concentrations of inflammatory markers-C-reactive protein, interleukin-6, tumor necrosis factor-α and soluble interleukin-2 receptor. Oxidative and nitrosative stress also plays a role in the pathophysiology of MDD. Notably, increased levels of lipid peroxidation markers are characteristic of MDD. Dysregulation of the stress axis, along with increased cortisol levels, have also been reported in MDD. Alterations in growth factors, with a significant decrease in brain-derived neurotrophic factor and an increase in fibroblast growth factor-2 and insulin-like growth factor-1 concentrations have also been found in MDD. Finally, kynurenine metabolites, increased glutamate and decreased total cholesterol also hold promise as reliable biomarkers for MDD. Research in the field of MDD biomarkers is hindered by insufficient understanding of MDD etiopathogenesis, substantial heterogeneity of the disorder, common co-morbidities and low specificity of biomarkers. The construction of biomarker panels and their evaluation with use of new technologies may have the potential to overcome the above mentioned obstacles.

Psychological Predictors for Depression and Burnout Among German Junior Elite Athletes

There exists a strong need for research in clinical sport psychology which does not merely gather information on prevalence rates for psychological disorders and case studies of affected athletes. Rather, research should also uncover the underlying psychological variables which increase the risk for depression and burnout in elite athletes. Many studies gather general factors (e.g., gender, injury, sport discipline) and stay on a more descriptive level. Both constructs (burnout and depression) are based on a temporal, stress-related process model assuming the development of either syndrome results from unfavorable personal (e.g., dysfunctional attitudes, perfectionism, negative coping strategies) or environmental (e.g., cohesion) factors coexisting with severe stressors (i.e., chronic stress). Integrating this knowledge, we propose a shared model for depression and burnout in athletes: a sport specific diathesis-stress model. The present longitudinal study assesses data throughout one sporting season to analyze predictors for both constructs in junior elite athletes. Hierarchical multiple linear regression analyses resulted in six predictors for best model fit. The following factors demonstrated a significant impact on predicting (a) burnout or (b) depression scores at the end of the season: dysfunctional attitudes (a and b), coping strategies (a and b), perfectionism (a), recovery (b), stress (a) and the level of depression at onset (b). Variables such as cohesion or attributional style did not significantly predict depression or burnout. The study supports the structure of a process model (diathesis-stress model) for burnout and depression with the assumption of temporal progression. With some vulnerabilities and their temporal, developmental link identified, prevention can become athlete-specific, effective and economical.

Biochemical and Behavioral Characterization of IN14, a New Inhibitor of HDACs with Antidepressant-Like Properties

Evidence suggests that histone deacetylases (HDACs) inhibitors could be used as an effective treatment for some psychiatric and neurological conditions such as depression, anxiety and age-related cognitive decline. However, non-specific HDAC inhibiting compounds have a clear disadvantage regarding their efficacy and safety, thus the need to develop more selective ones. The present study evaluated the toxicity, the capacity to inhibit HDAC activity and antidepressant-like activity of three recently described class I HDAC inhibitors IN01, IN04 and IN14, using A. salina toxicity test, in vitro fluorometric HDAC activity assay and forced-swimming test, respectively. Our data show that IN14 possesses a better profile than the other two. Therefore, the pro-cognitive and antidepressant effects of IN14 were evaluated. In the forced-swimming test model of depression, intraperitoneal administration of IN14 (100 mg/Kg/day) for five days decreased immobility, a putative marker of behavioral despair, significantly more than tricyclic antidepressant desipramine, while also increasing climbing behavior, a putative marker of motivational behavior. On the other hand, IN14 left the retention latency in the elevated T-maze unaltered. These results suggest that novel HDAC class I inhibitor IN14 may represent a promising new antidepressant with low toxicity and encourages further studies on this compound.

A novel NR3C2 polymorphism and the increased thyroid-stimulating hormone concentration are associated with venlafaxine treatment outcome in Chinese Han MDD patients

OBJECTIVE

We aimed to study the association among venlafaxine antidepressive outcome, NR3C2 gene polymorphisms and the change of two neuroendocrine hormones during treatment.

METHODS

195 Chinese Han major depressive disorder (MDD) patients were recruited and received a 6-week venlafaxine treatment in this study. Adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH) levels were measured at the beginning and at the end of treatment. Six single-nucleotide polymorphisms (SNPs) (NR3C2: rs1512325, rs1512342, rs2070951; NR3C1: rs6191, rs6196, rs10482614) were selected for high-throughput SNP genotyping. Allele and genotype frequencies of them were compared between remission and non-remission groups.

RESULTS

We found that genotype frequency of the rs1512325 located in the NR3C2 gene was significantly different between remission and non-remission groups respectively (p < 0.05). Meanwhile, the frequency of the rs1512325 C-allele was significantly lower (p < 0.05) in remission group. The TSH concentration significantly increased after venlafaxine treatment in remission group (p < 0.05).

CONCLUSION

The rs1512325 in NR3C2 gene and TSH concentration may be related to venlafaxine treatment outcome in Chinese Han MDD patients.

Antidepressant effects of ginsenoside Rf on behavioral change in the glial degeneration model of depression by reversing glial loss

Background

Depression is a common neuropsychiatric disease that shows astrocyte pathology. Ginsenoside Rf (G-Rf) is a saponin found in Panax ginseng which has been used to treat neuropsychiatric diseases. We aimed to investigate antidepressant properties of G-Rf when introduced into the L-alpha-aminoadipic acid (L-AAA)–infused mice model which is representative of a major depressive disorder that features diminished astrocytes in the brain.

Methods

L-AAA was infused into the prefrontal cortex (PFC) of mice to induce decrease of astrocytes. Mice were orally administered G-Rf (20 mg/kg) as well as vehicle only or imipramine (20 mg/kg) as controls. Depression-like behavior of mice was evaluated using forced swimming test (FST) and tail suspension test (TST). We observed recovery of astroglial impairment and increased proliferative cells in the PFC and its accompanied change in the hippocampus by Western blot and immunohistochemistry to assess the effect of G-Rf.

Results

After injection of L-AAA into the PFC, mice showed increased immobility time in FST and TST and loss of astrocytes without significant neuronal change in the PFC. G-Rf–treated mice displayed significantly more decreased immobility time in FST and TST than did vehicle-treated mice, and their immobility time almost recovered to those of the sham mice and imipramine-treated mice. G-Rf upregulated glial fibrillary acidic protein (GFAP) expression and Ki-67 expression in the PFC reduced by L-AAA and also alleviated astroglial change in the hippocampus.

Conclusion

G-Rf markedly reversed depression-like behavioral changes and exhibited protective effect against the astrocyte ablation in the PFC induced by L-AAA. These protective properties suggest that G-Rf might be a therapeutic agent for major depressive disorders.

Novel Treatment Targets Based on Insights in the Etiology of Depression: Role of IL-6 Trans-Signaling and Stress-Induced Elevation of Glutamate and ATP

Inflammation and psychological stress are risk factors for major depression and suicide. Both increase central glutamate levels and activate the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Both factors also affect the function of the chloride transporters, Na-K-Cl-cotransporter-1 (NKCC1) and K-Cl-cotransporter-2 (KCC2), and provoke interleukin-6 (IL-6) trans-signaling. This leads to measurable increases in circulating corticosteroids, catecholamines, anxiety, somatic and psychological symptoms, and a decline in cognitive functions. Recognition of the sequence of pathological events allows the prediction of novel targets for therapeutic intervention. Amongst others, these include blockade of the big-K potassium channel, blockade of the P2X4 channel, TYK2-kinase inhibition, noradrenaline α2B-receptor antagonism, nicotinic α7-receptor stimulation, and the Sgp130Fc antibody. A better understanding of downstream processes evoked by inflammation and stress also allows suggestions for tentatively better biomarkers (e.g., SERPINA3N, MARCKS, or ¹³C-tryptophan metabolism).

Liraglutide Activates mTORC1 Signaling and AMPA Receptors in Rat Hippocampal Neurons Under Toxic Conditions

The aim of the present study was to determine whether treatment with liraglutide, a glucagon-like peptide 1 (GLP-1) receptor agonist, would alter mammalian target of rapamycin complex 1 (mTORC1) signaling and/or α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor activity under dexamethasone-induced toxic conditions. Western blot analyses were performed to assess changes in mTORC1-mediated proteins, brain-derived neurotrophic factor (BDNF), and various synaptic proteins (PSD-95, synapsin I, and GluA1) in rat hippocampal cultures under toxic conditions induced by dexamethasone, which causes hippocampal cell death. Hippocampal dendritic outgrowth and spine formation were measured using immunostaining procedures. Dexamethasone significantly decreased the phosphorylation levels of mTORC1 as well as its downstream proteins. However, treatment with liraglutide prevented these reductions and significantly increased BDNF expression. The increase in BDNF expression was completely blocked by rapamycin and 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX). Liraglutide also recovered dexamethasone-induced decreases in the total length of hippocampal dendrites and reductions in spine density in a concentration-dependent manner. However, the positive effects of liraglutide on neural plasticity were abolished by the blockade of mTORC1 signaling and AMPA receptors. Furthermore, liraglutide significantly increased the expression levels of PSD-95, synapsin I, and GluA1, whereas rapamycin and NBQX blocked these effects. The present study demonstrated that liraglutide activated mTORC1 signaling and AMPA receptor activity as well as increased dendritic outgrowth, spine density, and synaptic proteins under toxic conditions in rat primary hippocampal neurons. These findings suggest that GLP-1 receptor (GLP-1R) activation by liraglutide may affect neuroplasticity through mTORC1 and AMPA receptors.

Serum-based microRNA biomarkers for major depression: MiR-16, miR-135a, and miR-1202

Background

Depression is a common medical condition with a high prevalence leading to emotional abnormality. Despite some drawbacks, depression currently diagnosed using a combination of patient interviews and self-report questionnaires. Recently, there is emerging emphasis to establish biomarkers to diagnosis and clinical management of depression. This case-control study was designed to develop microRNA (miRNA)-based serum biomarker for depression.

Materials and Methods

In this study, 39 patients with depression and 36 healthy controls were enrolled. Serum miRNAs gene expression was measured using real-time polymerase chain reaction (PCR) analysis; finally, the data represent as the 2^-ΔCt followed by further statistical analysis.

Results

The serum level of miR-16 was significantly (P < 0.001) down-regulated (mean: 0.9123 and standard deviation [SD]: 0.06) in compared to normal individuals (mean: 1.6848 and SD: 0.09). The concentration of miR-135a was also catastrophically decreased (P < 0.001) in the patients (mean: 1.160 and SD: 0.07) in compared to control (mean: 1.819 and SD: 0.09). The relative miR-1202 expression levels were significantly lower (P < 0.001) in the patients (mean: 0.1755 and SD: 0.01) than in the healthy individuals (mean: 0.2939 and SD: 0.01). The receiver operating characteristic curve analysis indicated the obvious separation between patient and healthy control, with an AUC of 0.75 (95% confidence interval [CI] = 0.642-0.858, P < 0.001), 0.72 (95% CI = 0.607-0.834, P < 0.001), and 0.74 (95% CI = 0.630-0.861, P < 0.001) for miR-16, miR-135a, and miR-1202, respectively. The data suggest that these miRNAs have a potential to be used as a biomarker of depression with sensitivity 77.8% and specificity of 61.5% for miR-16, 94.4% and 41.0% for miR-135a as well as 86.1% and 61.5% for miR-1202, respectively (P < 0.001).

Conclusion

Our findings showed that these miRNA can be used as a biomarker of depression diagnosis. MiR-135a and miR-1202 exhibited better sensitivity and specificity, respectively.

Investigation of Behavioral Dysfunctions Induced by Monoamine Depletions in a Mouse Model of Parkinson's Disease

Parkinson's disease (PD) is characterized not only by typical motor symptoms, but also by nonmotor symptoms in the early stages. In addition to the loss of dopaminergic (DAergic) neurons, progressive degenerations of noradrenergic (NA) and serotonergic (5-HT) neurons were also observed. However, the respective effects and interactions of these monoamine depletions on certain nonmotor symptoms are still largely unknown. In the present study, we performed selective depletions of NA, 5-HT and DA in mice by intraperitioneal injection of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), 4-chloro-L-phenylalanine (pCPA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), respectively. DSP-4 led to a 34% decrease in the number of NAergic neurons in the locus coeruleus, and MPTP led to a 30% decrease in the number of DAergic neurons in the substantia nigra. Although there was no obvious change in the number of 5-HTergic neurons in the dorsal raphe nucleus after pCPA treatment, the levels of 5-HT and its metabolite in the frontal cortex and hippocampus were reduced, respectively. Locomotor activity deficit was induced by DA depletion and a decrease in traveled distance was potentiated by additional NA depletion. Despair-associated depressive-like behavior could be observed in every group. Anxiety states emerged only from the combined depletion of two or three monoamines. However, combined depletion of the three monoamines dramatically induced anhedonia, and it could also aggravate the depressive-like and anxiety behavior. Furthermore, NA depletion significantly reduced spatial learning and memory ability, which was not enhanced by additional 5-HT or DA depletion. Our data highlighted the interactive role of NA, 5-HT and DA in the motor, emotional and cognitive deficits, providing new insight into the complex orchestration of impaired monoaminergic systems that related to the pathology of PD.

Senkyunolide A protects neural cells against corticosterone-induced apoptosis by modulating protein phosphatase 2A and α-synuclein signaling

Background

Depression is characterized by a pathological injury to the hippocampal neurons. Senkyunolide A (SenA) is one of the major active components of Dan-zhi-xiao-yao-san, which is widely used in the treatment of depression-related disorders.

Materials and methods

In the present study, it was hypothesized that the antidepressant effect of Dan-zhi-xiao-yao-san depended on the function of SenA and the authors attempted to reveal the molecular mechanism associated with the treatment. An in vitro depression model was induced using corticosterone (Cort), and the effect of SenA on the cell viability, apoptosis, and protein phosphatase 2A/α-synuclein (PP2A/α-syn) signaling was detected. To validate the mechanism driving the therapeutic effect of SenA, activity of PP2A and α-syn was modulated and the effect on neural cells was evaluated.

Results

The results showed that SenA protects Cort-induced cell apoptosis in PC12 cells. In addition, SenA increased Cort-induced reduction of PP2A activity, while it decreased the expression of p-PP2A, α-syn, and p-α-syn (Ser129). Further, modulation of PP2A activity with specific inhibitor okadaic acid (OA) increased Cort-induced cell apoptosis, while PP2A activator D-erythro-sphingosine (SPH) exhibited an opposite effect. The neuroprotective effects of SenA on neural cells also depended on inhibition of α-syn function, the regulation of which would influence the activity of PP2A in a negative loop.

Conclusion

Collectively, the results suggested that the neuroprotective effects of SenA were exerted by modulating activities of PP2A activities and α-syn. The findings partially explained the mechanism associated with the neuroprotective effect of SenA.

Variation of genes encoding KAT1, AADAT and IDO1 as a potential risk of depression development

Numerous data suggests that the disorders of tryptophan catabolites (TRYCATs) pathway, including a decreased level of tryptophan or evaluated concentration of harmful TRYCATs -kynurenine, quinolinic acid, 3-hydroxyanthranilic acid, 3-hydroxytryptophan - may cause the occurrence of DD symptoms. In this work, we assessed the relationship between single-nucleotide polymorphisms (SNPs) of KAT1, KAT2 and IDO1 gene encoding, and the risk of depression development. Our study was performed on the DNA isolated from peripheral blood of 281 depressed patients and 236 controls. We genotyped, by using TaqMan probes, four polymorphisms: c.*456G > A of KAT1 (rs10988134), c.975-7T > C of AADAT (rs1480544), c.-1849C > A (rs3824259) and c.-1493G > C(rs10089084)of IDO1. We found that only the A/A genotype of c.*456G > A - KAT1 (rs10988134) increased the risk of depression occurrence. Interestingly, when we stratified the study group according to gender, this relationship was present only in male population. However, a gene-gene analysis revealed a link between the T/T-C/C genotype of c.975-7T > C - AADAT (rs1480544)or c.-1493G > C - IDO1 (rs10089084) and C/C-C/A genotype of c.975-7T > C - AADAT (rs1480544)and c. -1849C > A - IDO1 (rs3824259) and the disease. Moreover, we found, that the c.975-7T > C - AADAT and c. *456G > A KAT1 (rs10988134) polymorphisms may modulate the effectiveness of selective serotonin reuptake inhibitors therapy. Concluding, our results confirm the hypothesis formulated in our recently published article that the SNPs of genes involved in TRYCATs pathway may modulate the risk of depression. This provides some further evidence that the pathway plays the crucial role in development of the disease.

The behavioral and molecular evaluation of effects of social instability stress as a model of stress-related disorders in adult female rats

The study aimed to test the hypotheses that chronic social instability stress (CSIS) alters behavioral and physiological parameters and expression of selected genes important for stress response and social behaviors. Adult female Sprague-Dawley rats were subjected to the 4-week CSIS procedure, which involves unpredictable rotation between phases of isolation and overcrowding. Behavioral analyses (Experiment 1) were performed on the same rats before and after CSIS (n = 16) and physiological and biochemical measurements (Experiment 2) were made on further control (CON; n = 7) and stressed groups (CSIS; n = 8). Behaviors in the open field test (locomotor and exploratory activities) and elevated-plus maze (anxiety-related behaviors) indicated anxiety after CSIS. CSIS did not alter the physiological parameters measured, i.e. body weight gain, regularity of estrous cycles, and circulating concentrations of stress hormones and sex steroids. QRT-PCR analysis of mRNA expression levels was performed on amygdala, hippocampus, prefrontal cortex (PFC), and hypothalamus. The main finding is that CSIS alters the mRNA levels for the studied genes in a region-specific manner. Hence, expression of POMC (pro-opiomelanocortin), AVPR1a (arginine vasopressin receptor), and OXTR (oxytocin receptor) significantly increased in the amygdala following CSIS, while in PFC and/or hypothalamus, POMC, AVPR1a, AVPR1b, OXTR, and ERβ (estrogen receptor beta) expression decreased. CSIS significantly reduced expression of CRH-R1 (corticotropin-releasing hormone receptor type 1) in the hippocampus. The directions of change in gene expression and the genes and regions affected indicate a molecular basis for the behavior changes. In conclusion, CSIS may be valuable for further analyzing the neurobiology of stress-related disorders in females.

The Role of MAPK and Dopaminergic Synapse Signaling Pathways in Antidepressant Effect of Electroacupuncture Pretreatment in Chronic Restraint Stress Rats

Acupuncture has demonstrated the function in ameliorating depressive-like behaviors via modulating PKA/CREB signaling pathway. To further confirm the antidepressant mechanism of EA on the mitogen-activated protein kinase (MAPK) and dopaminergic synapse signaling pathways, 4 target proteins were detected based on our previous iTRAQ analysis. Rats were randomly divided into control group, model group, and electroacupuncture (EA) group. Except for the control group, all rats were subjected to 28 days of chronic restraint stress (CRS) protocols to induce depression. In the EA group, EA pretreatment at Baihui (GV20) and Yintang (GV29) was performed daily (1 mA, 2 Hz, discontinuous wave, 20 minutes) prior to restraint. The antidepressant-like effect of EA was measured by body weight and open-field test. The protein levels of DAT, Th, Mapt, and Prkc in the hippocampus were examined by using Western blot. The results showed EA could ameliorate the depression-like behaviors and regulate the expression levels of Prkc and Mapt in CRS rats. The effect of EA on DAT and Th expression was minimal. These findings implied that EA pretreatment could alleviate depression through modulating MAPK signaling pathway. The role of EA on dopaminergic synapse signaling pathways needs to be further explored.

Cost-utility evaluation of vortioxetine in patients with Major Depressive Disorder experiencing inadequate response to alternative antidepressants in the United Kingdom

BACKGROUND

Patients frequently require several lines of therapy for treatment of major depressive episodes. This economic analysis details the management of patients who responded inadequately due to lack of efficacy or intolerability to two previous antidepressants in the UK.

METHODS

The model included a decision tree and a Markov component. Health states considered in the decision tree were remission, response, no response, withdrawal due to adverse events, relapse, recovery, and recurrence. The time horizon was 24 months. Patients were on third-line treatment for up to a 3-month acute phase and a 6-month maintenance phase. As third-line efficacy data were not available, inputs were calculated by adjusting original second-line data to third-line based on proportionate reductions observed in STAR*D. Equivalent efficacy was assumed for all comparators. Healthcare resource use and utilities were based on UK estimates.

RESULTS

Vortioxetine was a cost-effective treatment option at a threshold of £20,000/QALY vs. escitalopram, citalopram, sertraline, and was associated with more health benefits, less costs (was dominant) versus relevant third-line comparators venlafaxine and duloxetine. Agomelatine was found not to be a cost-effective option. The 22-month maintenance phase treatment scenario results were similar to the 6-month base case.

LIMITATIONS

Third-line efficacy data were not available. This highlights the need for studies in patients receiving third-line treatment.

CONCLUSION

This model provides an overview for the management of patients receiving third-line treatment where limited evidence currently exists. Vortioxetine, with its novel mechanism of action, is expected to be a dominant treatment option versus relevant comparators in the UK.

Activation of Brain Indoleamine-2,3-dioxygenase Contributes to Depressive-Like Behavior Induced by an Intracerebroventricular Injection of Streptozotocin in Mice

There is a lack of information concerning the molecular events underlying the depressive-like effect of an intracerebroventricular injection of streptozotocin (ICV-STZ) in mice. The elevated activity of the tryptophan-degrading enzyme indoleamine-2,3-dioxygenase (IDO) has been proposed to mediate depression in inflammatory disorders. In the present study, we reported that ICV-STZ activates IDO in the hippocampus of mice and culminates in depressive-like behaviors, as measured by the increased duration of immobility in the tail suspension test and decreased sucrose intake in the sucrose preference test. The blockade of IDO activation by the IDO inhibitor 1-methyltryptophan (1-MT) prevents the development of depressive-like behaviors and attenuates STZ-induced up-regulation of proinflammatory cytokines in the hippocampus. 1-MT abrogates kynurenine production and normalizes brain-derived neurotrophic factor (BDNF) and the kynurenine/tryptophan ratio, but does not protect the biomarkers of the serotonin (5-HT) system in the hippocampus of STZ-injected mice. These results implicate IDO as a critical molecular mediator of STZ-induced depressive-like behavior, likely through activation of the kynurenine pathway and subsequent reduction of BDNF levels. Impairment of the 5-HT system may reflect the inflammatory response induced by STZ and also contributes to observed depression symptoms. The present study not only provides evidence that IDO plays a critical role in mediating inflammation-induced depression but also supports the notion that neuroinflammation and the kynurenine pathway are important targets for novel therapeutic drugs for depression. In addition, this study provides new insights on the neurobiological mechanisms underlying ICV-STZ and indicates that this model could be employed in preclinical research of depression.

Role of brain-derived neurotrophic factor in the molecular neurobiology of major depressive disorder

Major depressive disorder (MDD) is one of the most common neuropsychiatric disorders, which affects up to 20% of people in their lifetime in the United States. The exact neurobiological mechanisms of MDD remain elusive, and the diagnostics are still uncertain. Basic and clinical research from recent years demonstrated that the etiology of MDD might be associated with genetic changes of neurotrophins, particularly brain-derived neurotrophic factor (BDNF). BDNF plays a key role in neuronal development and neurogenesis. However, the detailed mechanisms related to depression and antidepressant responses are not fully understood. This review summarizes the current knowledge of the causal relationship between BDNF and MDD, and describes the important role of BDNF in the progress of depression in animal models and patients with depressive disorders.

The Effect of Congenital and Postnatal Hypothyroidism on Depression-Like Behaviors in Juvenile Rats

OBJECTIVE

The aim of this study was to investigate depression-like behaviors of juvenile rats with congenital and postnatal hypothyroidism.

METHODS

Twenty-seven newborn rat pups were used. First, 6-month-old Wistar Albino female rats were impregnated. Methimazole (0.025% wt/vol) was given to dam rats from the first day of pregnancy until postnatal 21 days (P21) to generate pups with congenital hypothyroidism (n=8), whereas in the postnatal hypothyroidism group (n=10), methimazole was given from P0 to P21. In the control group (n=9), dam rats were fed ad libitum and normal tap water. Offspring were fed with breast milk from their mothers. The behavioral parameters were measured with the juvenile forced swimming test (JFST). The procedure of JFST consisted of two sessions in two consecutive days: the 15-minute pre-test on day 1 and the 5-minute test on day 2.

RESULTS

Increased immobility and decreased climbing duration were observed in both congenital and postnatal hypothyroidism groups. Decreased swimming duration was detected in the postnatal hypothyroidism group. Both hypothyroidism groups had a lower body weight gain compared with the control group, while the congenital hypothyroidism group had the lowest body weight.

CONCLUSION

Our results showed that hypothyroidism had negative effects on depression-like behavior as well as on growth and development. Both congenital and postnatal hypothyroidism caused an increase in immobility time in JFST. New studies are required to understand the differing results on depression-like behavior between congenital and postnatal hypothyroidism.