Major depression during interferon-alpha treatment: vulnerability and prevention

Comprehensive view of suicide: A neuro-immune-endocrine approach

Suicide is defined as the act of a person attempting to take their own life by causing death. Suicide is a complex phenomenon that is influenced by a multitude of factors, including psychosocial, cultural, and religious aspects, as well as genetic, biochemical, and environmental factors. From a biochemical perspective, it is crucial to consider the communication between the endocrine, immune, and nervous systems when studying the etiology of suicide. Several pathologies involve the bidirectional communication between the peripheral activity and the central nervous system by the action of molecules such as cytokines, hormones, and neurotransmitters. These humoral signals, when present in optimal quantities, are responsible for maintaining physiological homeostasis, including mood states. Stress elevates the cortisol and proinflammatory cytokines levels and alter neurotransmitters balance, thereby increasing the risk of developing a psychiatric disorder and subsequently the risk of suicidal behavior. This review provides an integrative perspective about the neurochemical, immunological, and endocrinological disturbances associated with suicidal behavior, with a particular focus on those alterations that may serve as potential risk markers and/or indicators of the state preceding such a tragic act.

Leisure-time physical activity is associated with depressive symptoms in cancer patients: Data from the NHANES 2007-2018

BACKGROUND

Cancer patients have a higher risk of depression and are associated with severe adverse prognosis. The relationship between leisure-time physical activity (LTPA) and depressive symptoms in cancer patients is currently unclear. Therefore, our study mainly explores the potential association between LTPA and the weekly cumulative time of LTPA with depressive symptoms in cancer patients.

METHODS

We included and analyzed 3368 cancer patients (aged >20 years) from the National Health and Nutrition Examination Survey (NHANES) of the United States from 1999 to 2018. The LTPA score was evaluated through a self-report questionnaire, while depressive symptoms were evaluated through the Health Questionnaire-9 (PHQ-9). Multiple logistic regression analysis was used to explore the relationship between LTPA duration and the occurrence of cancer-related depressiive symptoms. Linear correlation was studied using the restricted cubic spline method.

RESULTS

According to a fully adjusted multivariate logistic regression model with confounding variables, the odds ratio (OR) between LTPA and depressive symptoms in cancer patients in this study was 0.59 (95 % confidence interval = 0.39, 0.92; P = 0.02). When the LTPA level was ≥300 min/week, the incidence of depressive symptoms was reduced by 59 % (OR = 0.41, 95 % CI = 0.21, 0.83). In addition, the cubic spline method was used to obtain a linear negative correlation between LTPA duration and tumor depressive symptoms.

CONCLUSION

LTPA was negatively correlated with cancer-related depressive symptoms, and the cumulative time of LTPA/week was linearly correlated with depressive symptoms. The slope of the benefit curve changed significantly when the cumulative time of LTPA reached 600 min per week, suggesting that appropriately increasing LTPA had significant benefits on mental health of cancer patients.

Neurodevelopmental and Neuropsychiatric Disorders

This chapter will focus on microglial involvement in neurodevelopmental and neuropsychiatric disorders, particularly autism spectrum disorder (ASD), schizophrenia and major depressive disorder (MDD). We will describe the neuroimmune risk factors that contribute to the etiopathology of these disorders across the lifespan, including both in early life and adulthood. Microglia, being the resident immune cells of the central nervous system, could play a key role in triggering and determining the outcome of these disorders. This chapter will review preclinical and clinical findings where microglial morphology and function were examined in the contexts of ASD, schizophrenia and MDD. Clinical evidence points out to altered microglial morphology and reactivity, as well as increased expression of pro-inflammatory cytokines, supporting the idea that microglial abnormalities are involved in these disorders. Indeed, animal models for these disorders found altered microglial morphology and homeostatic functions which resulted in behaviours related to these disorders. Additionally, as microglia have emerged as promising therapeutic targets, we will also address in this chapter therapies involving microglial mechanisms for the treatment of neurodevelopmental and neuropsychiatric disorders.

Indoleamine 2,3-Dioxygenase as a Therapeutic Target for Alzheimer's Disease and Geriatric Depression

Neuroimmune-triggered neuroinflammation of the central nervous system is emerging as an important aetiopathogenic factor for multiple neurological disorders, including depression, dementia, Alzheimer's disease, multiple sclerosis and others. Tryptophan metabolism via the kynurenic pathway, which is initiated by the indoleamine-2,3-dioxygenase (IDO-1) enzyme, is a key regulator of the neuroimmune system and its associated neuroinflammatory effects. As discussed in this review, targeting the production of immunopathic and potentially neurotoxic kynurenine metabolites by inhibitory downregulation of IDO-1 may prove a viable target against inflammation-induced neurological conditions, particularly depression and dementia.

Effects of Ozone on Sickness and Depressive-like Behavioral and Biochemical Phenotypes and Their Regulation by Serum Amyloid A in Mice

Ozone (O₃) is an air pollutant that primarily damages the lungs, but growing evidence supports the idea that O₃ also harms the brain; acute exposure to O₃ has been linked to central nervous system (CNS) symptoms such as depressed mood and sickness behaviors. However, the mechanisms by which O₃ inhalation causes neurobehavioral changes are limited. One hypothesis is that factors in the circulation bridge communication between the lungs and brain following O₃ exposure. In this study, our goals were to characterize neurobehavioral endpoints of O₃ exposure as they relate to markers of systemic and pulmonary inflammation, with a particular focus on serum amyloid A (SAA) and kynurenine as candidate mediators of O₃ behavioral effects. We evaluated O₃-induced dose-, time- and sex-dependent changes in pulmonary inflammation, circulating SAA and kynurenine and its metabolic enzymes, and sickness and depressive-like behaviors in Balb/c and CD-1 mice. We found that 3 parts per million (ppm) O₃, but not 2 or 1 ppm O₃, increased circulating SAA and lung inflammation, which were resolved by 48 h and was worse in females. We also found that indoleamine 2,3-dioxygenase (Ido1) mRNA expression was increased in the brain and spleen 24 h after 3 ppm O₃ and that kynurenine was increased in blood. Sickness and depressive-like behaviors were observed at all O₃ doses (1-3 ppm), suggesting that behavioral responses to O₃ can occur independently of increased SAA or neutrophils in the lungs. Using SAA knockout mice, we found that SAA did not contribute to O₃-induced pulmonary damage or inflammation, systemic increases in kynurenine post-O₃, or depressive-like behavior but did contribute to weight loss. Together, these findings indicate that acute O₃ exposure induces transient symptoms of sickness and depressive-like behaviors that may occur in the presence or absence of overt pulmonary neutrophilia and systemic increases of SAA. SAA does not appear to contribute to pulmonary inflammation induced by O₃, although it may contribute to other aspects of sickness behavior, as reflected by a modest effect on weight loss.

Lipopolysaccharide-induced changes in effort-related motivational function: Interactions with 2-deoxyglucose

Inflammation is linked to motivational deficits seen in depression and other disorders. Lipopolysaccharide (LPS) induces an inflammatory response and impairs motivated behavior in humans and rodents. It has been suggested that inflammation can shift metabolic needs to functions that warrant more response to the perceived threat (e.g., fighting infection), therefore altering aspects of motivation. Animal models have been developed to assess alterations in motivated behavior by giving the animal the option to work (i.e., lever press) for a highly palatable food reward vs. approaching and consuming a freely available, albeit less preferred, food. This model was used to determine if administration of 2-deoxy-D-glucose (2DG), a substance that inhibits glucose uptake and glycolysis, could reverse the motivational deficits induced by LPS in rats. A food preference/intake task was also conducted to see if LPS affected intake of the highly palatable vs. less palatable foods when both are freely available. It was hypothesized that 2-DG would reverse the motivational deficits caused by LPS and there would be no effect on food preference/intake of the highly palatable food. Results showed that 2-DG significantly reversed LPS effects at the lowest dose, while methylphenidate did not. The food intake/preference tests showed that LPS significantly decreased food intake of both foods but did not alter preference for the highly palatable food compared to vehicle. These results suggest that in addition to having effects on exertion of effort during instrumental behavior, LPS also has direct effects on primary food motivation.

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.

Is depression the missing link between inflammatory mediators and cancer?

Patients with cancer are at greater risk of developing depression in comparison to the general population and this is associated with serious adverse effects, such as poorer quality of life, worse prognosis and higher mortality. Although the relationship between depression and cancer is now well established, a common underlying pathophysiological mechanism between the two conditions is yet to be elucidated. Existing theories of depression, based on monoamine neurotransmitter system dysfunction, are insufficient as explanations of the disorder. Recent advances have implicated neuroinflammatory mechanisms in the etiology of depression and it has been demonstrated that inflammation at a peripheral level may be mirrored centrally in astrocytes and microglia serving to promote chronic levels of inflammation in the brain. Three major routes to depression in cancer in which proinflammatory mediators are implicated, seem likely. Activation of the kynurenine pathway involving cytokines, increases tryptophan catabolism, resulting in diminished levels of serotonin which is widely acknowledged as being the hallmark of depression. It also results in neurotoxic effects on brain regions thought to be involved in the evolution of major depression. Proinflammatory mediators also play a crucial role in impairing regulatory glucocorticoid mediated feedback of the hypothalamic-pituitary-adrenal axis, which is activated by stress and considered to be involved in both depression and cancer. The third route is via the glutamatergic pathway, whereby glutamate excitotoxicity may lead to depression associated with cancer. A better understanding of the mechanisms underlying these dysregulated and other newly emerging pathways may provide a rationale for therapeutic targeting, serving to improve the care of cancer patients.

The Pharmacologically Active Alkaloid Cryptolepine Activates a Type 1 Interferon Response That Is Independent of MAVS and STING Pathways

Type 1 interferons (IFN-1) are pleiotropic cytokines with well-established anticancer and antiviral properties, particularly in mucosal tissues. Hence, natural IFN-1-inducing treatments are highly sought after in the clinic. Here, we report for the first time that cryptolepine, a pharmacoactive alkaloid in the medicinal plant Cryptolepis sanguinolenta, is a potent IFN-1 pathway inducer. Cryptolepine increased the transcript levels of JAK1, TYK2, STAT1, STAT2, IRF9, and OAS3, as well as increased the accumulation of STAT1 and OAS3 proteins, similar to recombinant human IFN-α. Cryptolepine effects were observed in multiple cell types including a model of human macrophages. This response was maintained in MAVS and STING-deficient cell lines, suggesting that cryptolepine effects are not mediated by nucleic acids released upon nuclear or organelle damage. In agreement, cryptolepine did not affect cell viability in concentrations that triggered potent IFN-1 activation. In addition, we observed no differences in the presence of a pharmacological inhibitor of TBK1, a pleiotropic kinase that is a converging point for Toll-like receptors (TLRs) and nucleic acid sensors. Together, our results demonstrate that cryptolepine is a strong inducer of IFN-1 response and suggest that cryptolepine-based medications such as C. sanguinolenta extract could be potentially tested in resource-limited regions of the world for the management of chronic viral infections as well as cancers.

Blockade of kappa-opioid receptors amplifies microglia-mediated inflammatory responses

Brain kappa-opioid receptors (KORs) are implicated in the pathophysiology of depressive and anxiety disorders, stimulating interest in the therapeutic potential of KOR antagonists. Research on KOR function has tended to focus on KOR-expressing neurons and pathways such as the mesocorticolimbic dopamine system. However, KORs are also expressed on non-neuronal cells including microglia, the resident immune cells in the brain. The effects of KOR antagonists on microglia are not understood despite the potential contributions of these cells to overall responsiveness to this class of drugs. Previous work in vitro suggests that KOR activation suppresses proinflammatory signaling mediated by immune cells including microglia. Here, we examined how KOR antagonism affects microglia function in vivo, together with its effects on physiological and behavioral responses to an immune challenge. Pretreatment with the prototypical KOR antagonist JDTic potentiates levels of proinflammatory cytokines (IL-1β, IL-6) in blood following administration of lipopolysaccharide (LPS), an immune-activating agent, without triggering effects on its own. Using magnetic-activated cell sorting (MACs), we found that KOR antagonism potentiates LPS-induced cytokine expression within microglia. This effect is accompanied by potentiation of LPS-induced hyperthermia, although reductions in body weight and locomotion were not affected. Histological analyses confirm that LPS produces visible changes in microglia morphology consistent with activation, but this effect is not altered by KOR antagonism. Considering that inflammation is increasingly implicated in depressive and anxiety disorders, these findings raise the possibility that KOR antagonist actions on microglia may detract from actions on neurons that contribute to their therapeutic potential.

Lower Levels of GABAergic Function Markers in Corticotropin-Releasing Hormone-Expressing Neurons in the sgACC of Human Subjects With Depression

RATIONALE

A previous transcriptome meta-analysis revealed significantly lower levels of corticotropin-releasing hormone (CRH) mRNA in corticolimbic brain regions in major depressive disorder (MDD) subjects, suggesting that cortical CRH-expressing (CRH+) cells are affected in MDD. Rodent studies show that cortical CRH is mostly expressed in GABAergic interneurons; however, the characteristic features of CRH+ cells in human brain cortex and their association with MDD are largely unknown.

METHODS

Subgenual anterior cingulate cortex (sgACC) of human subjects without brain disorders were labeled using fluorescent in situ hybridization (FISH) for CRH and markers of excitatory (SLC17A7), inhibitory (GAD1) neurons, as well as markers of other interneuron subpopulations (PVALB, SST, VIP). MDD-associated changes in CRH+ cell density and cellular CRH expression (n = 6/group) were analyzed. RNA-sequencing was performed on sgACC CRH+ interneurons from comparison and MDD subjects (n = 6/group), and analyzed for group differences. The effect of reduced BDNF on CRH expression was tested in mice with blocked TrkB function.

RESULTS

About 80% of CRH+ cells were GABAergic and 17.5% were glutamatergic. CRH+ GABAergic interneurons co-expressed VIP (52%), SST (7%), or PVALB (7%). MDD subjects displayed lower CRH mRNA levels in GABAergic interneurons relative to comparison subjects without changes in cell density. CRH+ interneurons show transcriptomic profile suggesting lower excitability and less GABA release and reuptake. Further analyses suggested that these molecular changes are not mediated by altered glucocorticoid feedback and potentially occur downstream for a common modulator of neurotrophic function.

SUMMARY

CRH+ cells in human sgACC are a heterogeneous population of GABAergic interneurons, although largely co-expressing VIP. Our data suggest that MDD is associated with reduced markers of inhibitory function in sgACC CRH+ interneurons, and provide further evidence for impaired GABAergic function in the cortex in MDD.

Choroid plexus enlargement is associated with neuroinflammation and reduction of blood brain barrier permeability in depression

BACKGROUND

Recent studies have shown that choroid plexuses (CP) may be involved in the neuro-immune axes, playing a role in the interaction between the central and peripheral inflammation. Here we aimed to investigate CP volume alterations in depression and their associations with inflammation.

METHODS

51 depressed participants (HDRS score > 13) and 25 age- and sex-matched healthy controls (HCs) from the Wellcome Trust NIMA consortium were re-analysed for the study. All the participants underwent full peripheral cytokine profiling and simultaneous [11C]PK11195 PET/structural MRI imaging for measuring neuroinflammation and CP volume respectively.

RESULTS

We found a significantly greater CP volume in depressed subjects compared to HCs (t(76) = +2.17) that was positively correlated with [11C]PK11195 PET binding in the anterior cingulate cortex (r = 0.28, p = 0.02), prefrontal cortex (r = 0.24, p = 0.04), and insular cortex (r = 0.24, p = 0.04), but not with the peripheral inflammatory markers: CRP levels (r = 0.07, p = 0.53), IL-6 (r = -0.08, p = 0.61), and TNF-α (r = -0.06, p = 0.70). The CP volume correlated with the [11C]PK11195 PET binding in CP (r = 0.34, p = 0.005). Integration of transcriptomic data from the Allen Human Brain Atlas with the brain map depicting the correlations between CP volume and PET imaging found significant gene enrichment for several pathways involved in neuroinflammatory response.

CONCLUSION

This result supports the hypothesis that changes in brain barriers may cause reduction in solute exchanges between blood and CSF, disturbing the brain homeostasis and ultimately contributing to inflammation in depression. Given that CP anomalies have been recently detected in other brain disorders, these results may not be specific to depression and might extend to other conditions with a peripheral inflammatory component.

Host Manipulation Mechanisms of SARS-CoV-2

Viruses are the simplest of pathogens, but possess sophisticated molecular mechanisms to manipulate host behavior, frequently utilizing molecular mimicry. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to bind to the host receptor neuropilin-1 in order to gain entry into the cell. To do this, the virus utilizes its spike protein polybasic cleavage site (PCS), which mimics the CendR motif of neuropilin-1's endogenous ligands. In addition to facilitating cell entry, binding to neuropilin-1 has analgesic effects. We discuss the potential impact of neuropilin-1 binding by SARS-CoV-2 in ameliorating sickness behavior of the host, and identify a convergent evolutionary strategy of PCS cleavage and subsequent neuropilin binding in other human viruses. In addition, we discuss the evolutionary leap of the ancestor of SARS-COV-2, which involved acquisition of the PCS thus faciliting binding to the neuropilin-1 receptor. Acquisition of the PCS by the ancestor of SARS-CoV-2 appears to have led to pleiotropic beneficial effects including enhancement of cell entry via binding to ACE2, facilitation of cell entry via binding to neuropilin-1, promotion of analgesia, and potentially the formation of decoy epitopes via enhanced shedding of the S1 subunit. Lastly, other potential neuromanipulation strategies employed by SARS-CoV-2 are discussed, including interferon suppression and the resulting reduction in sickness behavior, enhanced transmission through neurally mediated cough induction, and reduction in sense of smell.

Reconsidering the reasons for heightened inflammation in major depressive disorder

BACKGROUND

Increased circulating pro-inflammatory markers have repeatedly been associated with major depressive disorder (MDD). However, it remains unclear whether inflammation represents a causal mechanism for MDD, or whether the association is influenced by confounding factors such as body mass index (BMI).

METHODS

To better understand this complex relationship, we generated polygenic risk scores (PRS) for MDD and BMI in a population cohort and attempted to isolate the impact these potential risk factors have on adulthood inflammation. Peripheral blood samples were collected as part of the South East London Community Health study, where we generated individualized PRS for MDD and BMI and quantified inflammatory markers using multiplex ELISA-based technology. We performed linear regressions to investigate the effects of PRS for MDD and BMI on inflammatory marker levels.

RESULTS

Out of 35 inflammatory markers, we found a nominal effect of PRS for MDD on interleukin-10. We also found a significant positive effect of BMI on nine inflammatory markers, of which the two most strongly affected markers, interleukin-6 (IL-6) and C-reactive protein (CRP), were also nominally predicted by BMI PRS.

LIMITATIONS

The study utilized a cross-sectional design with a moderately sized sample.

CONCLUSIONS

Our findings suggest there may not be a shared genetic mechanism contributing to MDD and higher inflammatory marker levels. However, there may be shared genetic etiology between BMI and adulthood levels of CRP and IL-6. Therefore, polygenic risk scores for BMI may represent a useful indicator for heightened levels of inflammation in adulthood.

Hepatitis C Virus Infection and the New Therapeutical Approach

Hepatitis C virus represents one of the most important public health problems nowadays. Several epidemiological studies have shown a continuous increasing rate of prevalence and incidence with severe consequences in terms of mortality. During the last decades, the treatment of the liver infection has evolved, and now there are available new therapies with better side-effect' profiles and bigger efficiency. The needs for more therapeutically efficacy also stand behind the numerous comorbidities associated to the liver disease, and also for assuring better quality of life for patients and their families.

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.

The pandemic exposes human nature: 10 evolutionary insights

Humans and viruses have been coevolving for millennia. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes COVID-19) has been particularly successful in evading our evolved defenses. The outcome has been tragic-across the globe, millions have been sickened and hundreds of thousands have died. Moreover, the quarantine has radically changed the structure of our lives, with devastating social and economic consequences that are likely to unfold for years. An evolutionary perspective can help us understand the progression and consequences of the pandemic. Here, a diverse group of scientists, with expertise from evolutionary medicine to cultural evolution, provide insights about the pandemic and its aftermath. At the most granular level, we consider how viruses might affect social behavior, and how quarantine, ironically, could make us susceptible to other maladies, due to a lack of microbial exposure. At the psychological level, we describe the ways in which the pandemic can affect mating behavior, cooperation (or the lack thereof), and gender norms, and how we can use disgust to better activate native "behavioral immunity" to combat disease spread. At the cultural level, we describe shifting cultural norms and how we might harness them to better combat disease and the negative social consequences of the pandemic. These insights can be used to craft solutions to problems produced by the pandemic and to lay the groundwork for a scientific agenda to capture and understand what has become, in effect, a worldwide social experiment.

Depression in patients with spondyloarthritis: prevalence, incidence, risk factors, mechanisms and management

Depression is a major neuropsychiatric disorder common in patients with rheumatological conditions including spondyloarthritis (SpA). It is associated with higher disease activity, functional impairment, poor treatment response and quality of life in patients with musculoskeletal disorders. Using ankylosing spondylitis (AS) and psoriatic arthritis (PsA) as examples, we have reviewed the evidence regarding the burden, risk factors, potential mechanisms and clinical management of depression in spondyloarthritis. The prevalence of depression is higher in patients with AS and PsA compared with the general population, with evidence of moderate/severe depression in about 15% of patients with AS or PsA. Mild depression is even more common and estimated to be present in about 40% of patients with AS. In addition to conventional risk factors such as stressful life events and socioeconomic deprivation, increased risk of depression in SpA may be associated with disease-related factors, such as disease activity, poor quality of life, fatigue, and sleep disturbances. Emerging evidence implicates inflammation in the aetiology of depression, which could also be a shared mechanism for depression and chronic inflammatory conditions such as AS and PsA. It is imperative for clinicians to actively assess and treat depression in SpA, as this could improve treatment adherence, quality of life, and overall long-term clinical and occupational outcomes. The use of validated tools can aid recognition and management of depression in rheumatology clinics. Management of depression in SpA, especially when to refer to specialist mental health services, are discussed.

Prophylactic (R,S)-ketamine selectively protects against inflammatory stressors

Individuals with peripheral inflammation are a particularly vulnerable population for developing depression and are also more resistant towards traditional antidepressants. This signals the need for novel drugs that can effectively treat this patient population. Recently, we have demonstrated that (R,S)-ketamine is a prophylactic against a variety of stressors, but have yet to test if it is protective against inflammatory-induced vulnerability to a stressor. Here, male 129S6/SvEv mice were administered saline or (R,S)-ketamine (30 mg/kg) 6 days before an injection of vehicle (VEH) or lipopolysaccharide (LPS) (0.83 or 1.0 mg/kg, serotypes O111:B4 or O127:B8). Twenty-four hours after LPS administration, mice were administered a contextual fear conditioning (CFC) paradigm, followed by a context re-exposure and the forced swim test (FST). In a separate cohort, we tested if (R,S)-ketamine was effective as a prophylactic against polyinosinic-polycytidylic acid (PIC), a viral mimetic. (R,S)-ketamine was effective as a prophylactic for attenuating learned fear in the O111:B4 and O127:B8 strains of LPS. (R,S)-ketamine was also effective as a prophylactic for decreasing stress-induced depressive-like behavior in the O111:B4 and O127:B8 strains of LPS. Both of these effects were limited to administration of 1.0, but not 0.83 mg/kg of the O111:B4 and O127:B8 strains of LPS. (R,S)-ketamine was not effective against either stress phenotype following PIC administration. These data suggest that prophylactic (R,S)-ketamine may protect against selective inflammation-induced stress phenotypes following an inflammatory challenge. Future studies will be necessary to determine if (R,S)-ketamine can be useful in patient populations with peripheral inflammation.

Cytokine secretion and the risk of depression development in patients with connective tissue diseases

Research in the past two decades has revolutionized our understanding of depressive illnesses. Proinflammatory cytokines have become a point of interest in the interconnecting areas of neuropsychiatric and autoimmune diseases. The cytokine hypothesis of depression suggests that pro-inflammatory cytokines play a primary role in the mediation of the pathophysiological characteristics of major depression, in which an inflammatory process may be induced by external and internal stressors, such as psychological and inflammatory diseases, respectively. The higher prevalence of depression, particularly in patients with chronic autoimmune connective tissue disorders (CTD), suggests that depression may present a dysfunctional adaptation of cytokine-induced sickness, which could manifest in times of an exacerbated activation of the innate immune system. Inflammation is thought to contribute to the development of clinical depression through its ability to induce sickness behaviors corresponding to the neurovegetative features of depression, through the dysregulation of the hypothalamic-pituitary-adrenal axis, alterations in neurotransmitter synthesis and reuptake, and through its involvement in the neuroprogression pathways. This review explores the complex interrelationships in which inflammatory responses alter neuroendocrine and neuropsychological regulation contributing to depressive symptoms in CTD. The prevalence and characteristics of depression, and its correlation to the levels of inflammatory cytokines and disease activity among different CTD will be reviewed.

Cytokine alterations and cognitive impairment in major depressive disorder: From putative mechanisms to novel treatment targets

Overwhelming evidence indicates the involvement of immune-inflammatory processes in the pathophysiology of major depressive disorder (MDD). Peripheral cytokine alterations serve as one of most consistently reported indices of subthreshold inflammatory state observed in MDD. Although cytokines cannot pass directly through the blood-brain barrier, a number of transport mechanisms have been reported. In addition, peripheral cytokines may impact central nervous system via downstream effectors of their biological activity. Animal model studies have provided evidence that cytokines might impact cognitive performance through direct and indirect effects on long-term potentiation, neurogenesis and synaptic plasticity. Therefore, it has been hypothesized that cytokine alterations might contribute to cognitive impairment that is widely observed in MDD and persists beyond episodes of acute relapse in the majority of patients. Although several studies have provided that peripheral cytokine alterations might be related to cognitive deficits in patients with MDD, the quality of evidence still leaves much to be desired due to methodological heterogeneity and limitations. In this article, we provide an overview of studies investigating the association between peripheral cytokine alterations and cognitive performance in MDD, discuss underlying mechanisms and neural substrates. Finally, we propose possible treatment targets related to cytokine alterations taking into account existing evidence for antidepressant efficacy of anti-inflammatory pharmacological treatment modalities.

Comparison of fluoxetine and 1-methyl-L-tryptophan in treatment of depression-like illness in Bacillus Calmette-Guerin-induced inflammatory model of depression in mice

BACKGROUND

The inflammatory response system has been implicated in the pathophysiology of major depression. The pro-inflammatory cytokines like interferon-γ induce the enzyme indoleamine-2,3-dioxygenase (IDO) of the kynurenine pathway of tryptophan metabolism. The induction of IDO reduces the availability of tryptophan for serotonin synthesis. Furthermore, the metabolites of kynurenine pathway have neurotoxic property, which along with decreased serotonin may account for depression-like illness.

METHODS

The aim of this study was to compare the effects of treatment with fluoxetine and 1-methyl-L-tryptophan (1-MT) on Bacillus Calmette-Guerin (BCG)-induced inflammatory model of depression in mice. Behavioral tests included locomotor activity, forced swim test (FST) and tail suspension test (TST). Oxidative stress was assessed by examining the levels of thiobarbituric acid reactive species (TBARS) and non-protein thiols (NP-SH) in homogenized whole brain samples. Comet assays were performed to assess neurotoxicity.

RESULTS

The results of this study demonstrate that BCG treatment resulted in an increase in duration of immobility in FST and TST as compared to the saline group. Further, it produced a significant increase in the brain TBARS levels and decrease in the brain NP-SH levels. The hippocampal tissue from BCG group had significantly more comet cells than the saline group. 1-MT and fluoxetine were able to reverse the BCG-induced depression-like behavior and the derangement in oxidative stress parameters. Fluoxetine and 1-MT also reversed the BCG-induced neurotoxicity in such mice.

CONCLUSIONS

1-Methyl-L-tryptophan exhibits antidepressant-like effect comparable to that of fluoxetine in treating BCG-induced depression-like behavior in mice.

Pathogen-Host Defense in the Evolution of Depression: Insights into Epidemiology, Genetics, Bioregional Differences and Female Preponderance

Significant attention has been paid to the potential adaptive value of depression as it relates to interactions with people in the social world. However, in this review, we outline the rationale of why certain features of depression including its environmental and genetic risk factors, its association with the acute phase response and its age of onset and female preponderance appear to have evolved from human interactions with pathogens in the microbial world. Approaching the relationship between inflammation and depression from this evolutionary perspective yields a number of insights that may reveal important clues regarding the origin and epidemiology of the disorder as well as the persistence of its risk alleles in the modern human genome.

Effort-related motivational effects of the pro-inflammatory cytokine interleukin-6: pharmacological and neurochemical characterization

RATIONALE

Motivational dysfunctions such as anergia, fatigue, and reduced effort expenditure are common in patients with depression and other disorders. Pro-inflammatory cytokines are implicated in depression, and cytokine administration induces motivational deficits in humans.

OBJECTIVES

These studies focused on the effects of the cytokine interleukin-6 (IL-6) on effort-related decision-making.

METHODS

Rats were assessed using the concurrent fixed ratio 5-lever pressing/chow feeding choice procedure, which measures the tendency of rats to work for a preferred food (high carbohydrate pellets) in the presence of a concurrently available but less preferred substitute (lab chow).

RESULTS

IL-6 (2.0-8.0 μg/kg IP) shifted choice behavior, significantly decreasing lever pressing and increasing chow intake. Further experiments showed that the adenosine A2A antagonist MSX-3 and the stimulant methylphenidate attenuated the effort-related impairments produced by IL-6, increasing lever pressing and decreasing chow intake in IL-6 treated rats. The same doses of IL-6 did not alter food intake or preference in parallel free-feeding choice studies, demonstrating that these low doses were not altering preference for the high carbohydrate pellets or generally suppressing appetite. Also, IL-6 did not affect body temperature. Microdialysis studies showed that 8.0 μg/kg IL-6 significantly decreased extracellular dopamine in nucleus accumbens core.

CONCLUSIONS

In summary, IL-6 reduces the tendency to work for food, even at low doses that do not produce fever or loss of appetite. Dopaminergic mechanisms may be involved in these effort-related effects. This research has implications for the involvement of cytokines in motivational dysfunctions such as anergia and fatigue.

Activational and effort-related aspects of motivation: neural mechanisms and implications for psychopathology

Motivation has been defined as the process that allows organisms to regulate their internal and external environment, and control the probability, proximity and availability of stimuli. As such, motivation is a complex process that is critical for survival, which involves multiple behavioural functions mediated by a number of interacting neural circuits. Classical theories of motivation suggest that there are both directional and activational aspects of motivation, and activational aspects (i.e. speed and vigour of both the instigation and persistence of behaviour) are critical for enabling organisms to overcome work-related obstacles or constraints that separate them from significant stimuli. The present review discusses the role of brain dopamine and related circuits in behavioural activation, exertion of effort in instrumental behaviour, and effort-related decision-making, based upon both animal and human studies. Impairments in behavioural activation and effort-related aspects of motivation are associated with psychiatric symptoms such as anergia, fatigue, lassitude and psychomotor retardation, which cross multiple pathologies, including depression, schizophrenia, and Parkinson's disease. Therefore, this review also attempts to provide an interdisciplinary approach that integrates findings from basic behavioural neuroscience, behavioural economics, clinical neuropsychology, psychiatry, and neurology, to provide a coherent framework for future research and theory in this critical field. Although dopamine systems are a critical part of the brain circuitry regulating behavioural activation, exertion of effort, and effort-related decision-making, mesolimbic dopamine is only one part of a distributed circuitry that includes multiple neurotransmitters and brain areas. Overall, there is a striking similarity between the brain areas involved in behavioural activation and effort-related processes in rodents and in humans. Animal models of effort-related decision-making are highly translatable to humans, and an emerging body of evidence indicates that alterations in effort-based decision-making are evident in several psychiatric and neurological disorders. People with major depression, schizophrenia, and Parkinson's disease show evidence of decision-making biases towards a lower exertion of effort. Translational studies linking research with animal models, human volunteers, and clinical populations are greatly expanding our knowledge about the neural basis of effort-related motivational dysfunction, and it is hoped that this research will ultimately lead to improved treatment for motivational and psychomotor symptoms in psychiatry and neurology.

Polyunsaturated fatty acids moderate the effect of poor sleep on depression risk

Although potentially modifiable risk factors for interferon-alpha (IFN-α)-associated depression (IFN-MDD) have been identified, it is not currently known how they interact to confer risk. In the present study we prospectively investigated interactions among poor sleep quality, high-stress, pre-existing depressive symptoms, and polyunsaturated fatty acid status. Non-depressed hepatitis C patients (n=104) were followed prospectively during IFN-α therapy. IFN-MDD occurs in 20-40% of patients and was diagnosed using the Structured Clinical Interview of DSM-IV (SCID-IV), with incidence examined using Cox regression. Baseline Pittsburgh Sleep Quality Inventory (PSQI), Perceived Stress Scale (PSS), Beck Depression Inventory (BDI), and a range of plasma long-chain fatty acid levels were measured (gas chromatography) - focusing on the ratio of arachidonic acid (AA) to docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) (AA/EPA+DHA). The AA/EPA+DHA ratio (Β=0.40 ± 0.16; p=0.006), PSQI (Β=0.12 ± 0.04; p=0.001), PSS (Β=0.07 ± 0.02; p<0.001), and baseline BDI (Β=0.05 ± 0.02; p<0.001) each individually predicted IFN-MDD incidence. In step-wise Cox regression eliminating non-significant variables, two interactions remained significantly predictive: PSQI*AA/EPA+DHA (p=0.008) and PSS*AA/EPA+DHA (p=0.01). Receiver Operator Curves (ROC) were used to examine the specificity and sensitivity of IFN-MDD prediction. When sleep was normal (PSQI<5), AA/EPA+DHA was strongly predictive of IFN-MDD (AUC=91 ± 6; p=0.002). For example, among those with AA/EPA+DHA less than the median (4.15), none with PSQI<5 developed depression. Conversely, neither PSS nor PSQI was statistically associated with depression risk in those with an elevated AA/EPA+DHA ratio. These data demonstrate that the AA/EPA+DHA ratio moderates the effect of poor sleep on risk for developing IFN-MDD and may have broader implications for predicting and preventing MDD associated with inflammation.

The Promise and Limitations of Anti-Inflammatory Agents for the Treatment of Major Depressive Disorder

This review provides a critical perspective on recent meta-analyses suggesting that several anti-inflammatory modalities, including nonsteroidal anti-inflammatory drugs (NSAIDs), omega-3 fatty acids, and cytokine antagonist, possess generalizable antidepressant properties. By examining confounds and limitations in the available literature it is suggested that current data suggest that only a sub-group of individuals with major depressive disorder (MDD) have evidence of increased inflammatory biomarkers and it is in these individuals that anti-inflammatory agents show promise for reducing depressive symptoms. The treatment implications of this cautionary perspective are discussed.

Acute coronary syndrome-associated depression: the salience of a sickness response analogy?

Depression emerging in conjunction with acute coronary syndrome (ACS) is thought to constitute a distinct high-risk phenotype with inflammatory determinants. This review critically examines the notion put forward in the literature that ACS-associated depression constitutes a meaningful subtype that is qualitatively different from depressive syndromes observed in psychiatric patients; and evaluates the salience of an analogy to the acute sickness response to infection or injury as an explanatory model. Specific features differentiating ACS-associated depression from other phenotypes are discussed, including differences in depression symptom profiles, timing of the depressive episode in relation to ACS, severity of the cardiac event, and associated immune activation. While an acute sickness response analogy offers a plausible conceptual framework, concrete evidence is lacking for inflammatory activity as the triggering mechanism. It is likely that ACS-associated depression encompasses several causative scenarios.

Type I interferons in anticancer immunity

Type I interferons (IFNs) are known for their key role in antiviral immune responses. In this Review, we discuss accumulating evidence indicating that type I IFNs produced by malignant cells or tumour-infiltrating dendritic cells also control the autocrine or paracrine circuits that underlie cancer immunosurveillance. Many conventional chemotherapeutics, targeted anticancer agents, immunological adjuvants and oncolytic viruses are only fully efficient in the presence of intact type I IFN signalling. Moreover, the intratumoural expression levels of type I IFNs or of IFN-stimulated genes correlate with favourable disease outcome in several cohorts of patients with cancer. Finally, new anticancer immunotherapies are being developed that are based on recombinant type I IFNs, type I IFN-encoding vectors and type I IFN-expressing cells.

Proteomic changes in serum of first onset, antidepressant drug-naïve major depression patients

Major depressive disorder (MDD) is a complex and multi-factorial disorder. Although genetic factors and other molecular aspects of MDD have been widely studied, the underlying pathological mechanisms are still mostly unknown. We sought to investigate the pathophysiology of MDD by identifying and characterising serum molecular differences and their correlation to symptom severity in first onset, antidepressant drug-naïve MDD patients. We performed an exploratory molecular profiling study on serum samples of MDD patients and controls using multiplex immunoassay and label-free liquid chromatography mass spectrometry in data independent mode (LC-MSE). We included two independent cohorts of first onset, antidepressant drug-naïve MDD patients (n = 23 and 15) and matched controls (n = 42 and 21) in our study in order to validate the results. The main outcome included the following list of circulatory molecules changing and/or correlating to symptom severity: angiotensin-converting enzyme, acute phase proteins (e.g. ferritin and serotransferrin), brain-derived neurotrophic factor, complement component C4-B, cortisol, cytokines (e.g. macrophage migration inhibitory factor and interleukin-16), extracellular newly identified receptor for advanced glycosylation end products-binding protein, growth hormone and superoxide dismutase-1. This study provides evidence of an increased pro-inflammatory and oxidative stress response, followed by a hyperactivation of the HPA-axis in the acute stages of first onset MDD, as well as a dysregulation in growth factor pathways. These findings help to elucidate MDD related pathways in more detail and further studies may lead to identification of novel drug targets, including components of the inflammatory and oxidative stress response.

The common inflammatory etiology of depression and cognitive impairment: a therapeutic target

Chronic inflammation has been shown to contribute to the development of a wide variety of disorders by means of a number of proposed mechanisms. Depression and cognitive impairment are two such disorders which may share a closely linked inflammatory etiology. The ability of inflammatory mediators to alter the activity of enzymes, from key metabolic pathways, may help explain the connection between these disorders. The chronic up-regulation of the kynurenine pathway results in an imbalance in critical neuroactive compounds involving the reduction of tryptophan and elevation of tryptophan metabolites. Such imbalances have established implications in both depression and cognitive impairment. This may implicate the immune system as a potential therapeutic target in the treatment of these disorders. The most common treatment modalities currently utilized, involve drug interventions which act on downstream targets. Such treatments help to reestablish protein balances, but fail to treat the inflammatory basis of the disorder. The use of anti-inflammatory interventions, such as regular exercise, may therefore, contribute to the effectiveness of current drug interventions in the treatment of both depression and cognitive impairment.

Neuropsychiatric side-effects of interferon-alpha treatment: pathophysiology and therapeutic options

Interferon alpha (IFN-α) is the approved standard of care for chronic hepatitis C and B. Unfortunately, it has neuropsychiatric side-effects that have a major impact upon the quality of life and the drug adherence. The mechanism of IFN-α-induced behavioral changes is complex, involving interactions between the immune system, the endocrine system, the monoaminergic systems and the opioid receptors. Recent studies support the neurodegeneration hypothesis as a possible mechanism of IFN-α-induced depressive behavior. Although a meta-analysis showed that antidepressant pretreatment effectively reduces the incidence and severity of depressive symptoms, irrespective of pre-existing psychiatric disorders, it is not approved for prophylactic use. The "on demand" treatment strategy is justified as the majority of patients have only mild depressive symptoms. Patients with risk factors for depression undergoing IFN-α therapy need to be regularly screened and followed-up by a psychiatric specialist. Further studies should be conducted to show which therapy is the most appropriate to reduce the neuropsychiatric symptoms that are related to the use of IFN-α and to investigate the clinical significance of IFN-α-induced neurodegeneration.

Epigenetic changes associated with inflammation in breast cancer patients treated with chemotherapy

Inflammation has been associated with fatigue during and after various types of breast cancer treatments. We examined whether prior chemotherapy was associated with DNA methylation patterns that could explain persisting inflammation and/or fatigue in women treated for breast cancer. Prior to breast radiation therapy, DNA was extracted from peripheral blood mononuclear cells (PBMCs) of 61 Stage 0-IIIA breast cancer patients who had received partial mastectomy with or without chemotherapy. DNA methylation was assessed at >485,000 CpG sites across the genome along with fatigue and plasma inflammatory markers previously associated with fatigue. Compared to non-chemotherapy-treated, women who had received chemotherapy exhibited significantly decreased methylation at eight CpG sites (p<1.03×10(-7)) including four in exon 11 of transmembrane protein 49 (TMEM49), which demonstrated the largest decreases in methylation. Lower methylation at each identified CpG site was associated with increased plasma soluble tumor necrosis factor receptor 2 (sTNFR2) and interleukin (IL)-6 and mediated the relationship between chemotherapy and increases in these inflammatory biomarkers adjusting for multiple clinical and treatment characteristics. sTNFR2, but not CpG methylation status, was correlated with fatigue. Six months after breast radiation therapy, DNA methylation, inflammatory biomarkers and fatigue assessments were repeated in a subset of subjects (N=39). Reduced methylation in 4 of the 8 identified CpG sites was still observed in chemotherapy versus non-chemotherapy-treated patients, albeit with some decay indicating the dynamic and potentially reversible nature of the changes. Reduced methylation in these 4 CpG sites also continued to correlate with either increased sTNFR2 or IL-6, but not fatigue. In conclusion, prior chemotherapy treatment was associated with decreased methylation of CpG sites in DNA from PBMCs of breast cancer patients, which correlated with increased inflammatory markers prior to and 6months after radiation therapy. Persisting epigenetic changes secondary to chemotherapy may be one factor that contributes to inflammation and its consequences including cancer-related fatigue in vulnerable breast cancer patients.

Inflammation in children and adolescents with neuropsychiatric disorders: a systematic review

OBJECTIVE

There has been rapid growth in research regarding inflammation in neuropsychiatric disorders as it relates to youth. We therefore set out to systematically review the literature on inflammation and neuropsychiatric disorders in children and adolescents.

METHOD

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were included if proinflammatory markers (PIMs) in children and/or adolescents with neuropsychiatric disorders were measured.

RESULTS

Sixty-seven studies were included, involving 3,952 youth. Evidence for a proinflammatory state is strongest for autism spectrum disorders (ASD). PIMs are elevated in children and adolescents with major depressive disorder (MDD), bipolar disorder (BD), post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), Tourette's disorder (TD), attention-deficit/hyperactivity disorder (ADHD), and schizophrenia (SZ). However, the data are inconsistent. Evidence for specific PIMs is equivocal at this stage, although the findings in youth with MDD, BD, and PTSD converge with the extant adult literature in these areas. Definitive conclusions are limited by methodologic factors including cross-sectional and retrospective study design, between-study differences in specific markers and methods of analysis, small sample size, and other sources of heterogeneity.

CONCLUSION

The literature regarding inflammation among children and adolescents with neuropsychiatric disorders represents nearly 4,000 youth. There is preliminary evidence for elevated markers of inflammation in this population. Larger, prospective studies are needed to realize the goal of inflammatory markers informing clinical practice. In the interim, present findings suggest that further examination of this topic is warranted.

Mood disturbance after infection

OBJECTIVE

An aetiological link between acute infection and major depression has long been hypothesized, and is increasingly gaining recognition within contemporary literature. This review aims to examine the evidence for such a link, specifically between acute, self-limiting infection and major depression, and to summarize the current understanding of pathophysiological mechanisms underlying this link.

METHODS

Relevant articles were sourced via an online search of published literature from Embase, MEDLINE, PsycINFO and PubMed using a variety of search terms including mood disorder, depression, infection and inflammation. Additionally, a search for articles from the bibliographies of retrieved papers was conducted.

RESULTS

Findings from retrospective studies suggest an association between infection and subsequent mood disturbance, including major depression. This association has been confirmed by studies employing prospective observational or experimental challenge designs. The available evidence supports a multifactorial basis of vulnerability towards major depression in the context of acute infection. Genetic, neuroendocrine, autonomic and psychosocial factors may interact to potentiate the likelihood of a severe and prolonged depressive response to an immunological stressor in some individuals.

CONCLUSION

Mood disturbance is likely to have a host-protective role in the context of an acute sickness response to infection. However, this usually adaptive and reversible response may progress in some vulnerable individuals into a more sustained and severe pattern of behavioural and physiological changes of major depression. Further research is needed to delineate the factors that predispose, precipitate and perpetuate depression in the context of acute infective illness. Such insights will inform effective prevention and treatment strategies.

Altered inflammatory responsiveness in serotonin transporter mutant rats

Background

Growing evidence suggests that alterations of the inflammatory/immune system contribute to the pathogenesis of depression. Indeed, depressed patients exhibit increased levels of inflammatory markers in both the periphery and the brain, and high comorbidity exists between major depression and diseases associated with inflammatory alterations. In order to characterize the link between depression and inflammation, we aimed to investigate whether an altered inflammatory system is present in a genetic model of vulnerability for depression, namely rats with partial or total deletion of the serotonin transporter (SERT) gene.

Methods

Wild-type, heterozygous and homozygous SERT rats were analyzed under basal condition or following a challenge with an acute injection of lipopolysaccharide (LPS) and killed 24 h or 5 days later.

Results

We found that SERT mutant rats show altered cytokine expression in the dorsal and ventral hippocampus at basal conditions, and they also display an exacerbated cytokine response to the LPS challenge. Moreover, mutant rats exhibit differences in the expression of markers for microglia activation.

Conclusion

Based on these data, we suggest that basal or functional alterations of immune/inflammatory systems might contribute to the phenotype of SERT rats and to their heightened susceptibility to depressive-like behavior.

Inflammatory cytokines in depression: neurobiological mechanisms and therapeutic implications

Mounting evidence indicates that inflammatory cytokines contribute to the development of depression in both medically ill and medically healthy individuals. Cytokines are important for development and normal brain function, and have the ability to influence neurocircuitry and neurotransmitter systems to produce behavioral alterations. Acutely, inflammatory cytokine administration or activation of the innate immune system produces adaptive behavioral responses that promote conservation of energy to combat infection or recovery from injury. However, chronic exposure to elevated inflammatory cytokines and persistent alterations in neurotransmitter systems can lead to neuropsychiatric disorders and depression. Mechanisms of cytokine behavioral effects involve activation of inflammatory signaling pathways in the brain that results in changes in monoamine, glutamate, and neuropeptide systems, and decreases in growth factors, such as brain-derived neurotrophic factor. Furthermore, inflammatory cytokines may serve as mediators of both environmental (e.g. childhood trauma, obesity, stress, and poor sleep) and genetic (functional gene polymorphisms) factors that contribute to depression's development. This review explores the idea that specific gene polymorphisms and neurotransmitter systems can confer protection from or vulnerability to specific symptom dimensions of cytokine-related depression. Additionally, potential therapeutic strategies that target inflammatory cytokine signaling or the consequences of cytokines on neurotransmitter systems in the brain to prevent or reverse cytokine effects on behavior are discussed.

Brain-derived neurotrophic factor serum levels and genotype: association with depression during interferon-α treatment

Depression has been associated with inflammation, and inflammation may both influence and interact with growth factors such as brain-derived neurotrophic factor (BDNF). Both the functional Val66Met BDNF polymorphism (rs6265) and BDNF levels have been associated with depression. It is thus plausible that decreased BDNF could mediate and/or moderate cytokine-induced depression. We therefore prospectively employed the Beck Depression Inventory-II (BDI-II), the Hospital Anxiety and Depression Scale (HADS), and the Montgomery-Asberg Depression Rating Scale (MADRS) in 124 initially euthymic patients during treatment with interferon-alpha (IFN-α), assessing serum BDNF and rs6265. Using mixed-effect repeated measures, lower pretreatment BDNF was associated with higher depression symptoms during IFN-α treatment (F144,17.2=6.8; P<0.0001). However, although the Met allele was associated with lower BDNF levels (F1,83.0=5.0; P=0.03), it was only associated with increased MADRS scores (F4,8.9=20.3; P<0.001), and not the BDI-II or HADS. An exploratory comparison of individual BDI-II items indicated that the Met allele was associated with suicidal ideation, sadness, and worthlessness, but not neurovegetative symptoms. Conversely, the serotonin transporter promoter polymorphism (5-HTTLPR) short allele was associated with neurovegetative symptoms such as insomnia, poor appetite and fatigue, but not sadness, worthlessness, or suicidal ideation. IFN-α therapy further lowered BDNF serum levels (F4,37.7=5.0; P=0.003), but this decrease occurred regardless of depression development. The findings thus do not support the hypothesis that decreasing BDNF is the primary pathway by which IFN-α worsens depression. Nonetheless, the results support the hypothesis that BDNF levels influence resiliency against developing inflammatory cytokine-associated depression, and specifically to a subset of symptoms distinct from those influenced by 5-HTTLPR.

Predictors of psychopathological outcome during peg-interferon and ribavirin therapy in patients with chronic HCV-correlated hepatitis

Peg-interferon (Peg-IFN) and ribavirin (RBV) therapy is reported to induce psychiatric symptoms and syndromes in 20% of patients treated for Hepatitis C Virus (HCV) infection. Present study was aimed to quantify the phenomenon and assess the influence of psychiatric counseling over antiviral completion rate and the use of psychometric tools, in terms of prediction of psychopathological outcome. Ninety-six HCV patients were assessed, before antiviral treatment, by means of the Sheehan Disability Scale (SDS), Mood Disorder Questionnaire (MDQ), Symptom Checklist-90, and Internal State Scale (ISS). Sociodemographic and clinical variables and completion rate were collected. Binary logistic regression was performed to evaluate whether scores were predictive of psychiatric visit, development of psychiatric disorders, and need for treatment. Ninety-five patients (99%) completed antiviral treatment; 27 subjects (29%) needed psychiatric visit: among them, mood disorder was diagnosed in 15 (16%) and were pharmacologically treated. Baseline SDS and MDQ higher scores were found to be predictive of psychiatric visit [odds ratio (OR)=1.258, P<0.001 and OR=1.425, P=0.05, respectively]. Furthermore, higher MDQ score (P=0.017) and ISS hostility scores (OR=1.048, P=0.014) at baseline predicted the subsequent development of mood episodes, while ISS activation correlated negatively (OR=0.948, P=0.009). Finally, the need for treatment was predicted by higher scores at the MDQ and ISS activation items (OR=2.467, P=0.030; OR=0.970, P=0.038). Present findings suggest that psychiatric counseling may be needed in almost 30% of HCV patients on antiviral treatment, with positive influence over the completion rate. Baseline higher scores at psychometric questionnaires-MDQ-in particular, predictors of psychopathological outcome during Peg-IFN and RBV therapy in patients with chronic HCV-correlated hepatitis reflecting individual functioning before starting antiviral therapy and positive history for mood disorders, seem to predict psychiatric visit, onset of mood episodes, and need for psychopharmacological treatment. Further investigation is warranted to confirm results.

Molecular signatures of peripheral blood mononuclear cells during chronic interferon-α treatment: relationship with depression and fatigue

BACKGROUND

Interferon-alpha (IFN-α) treatment for infectious disease and cancer causes high rates of depression and fatigue, and has been used to investigate the impact of inflammatory cytokines on brain and behavior. However, little is known about the transcriptional impact of chronic IFN-α on immune cells in vivo and its relationship to IFN-α-induced behavioral changes.

METHOD

Genome-wide transcriptional profiling was performed on peripheral blood mononuclear cells (PBMCs) from 21 patients with chronic hepatitis C virus (HCV) either awaiting IFN-α therapy (n=10) or at 12 weeks of IFN-α treatment (n=11).

RESULTS

Significance analysis of microarray data identified 252 up-regulated and 116 down-regulated gene transcripts. Of the up-regulated genes, 2'-5'-oligoadenylate synthetase 2 (OAS2), a gene linked to chronic fatigue syndrome (CFS), was the only gene that was differentially expressed in patients with IFN-α-induced depression/fatigue, and correlated with depression and fatigue scores at 12 weeks (r=0.80, p=0.003 and r=0.70, p=0.017 respectively). Promoter-based bioinformatic analyses linked IFN-α-related transcriptional alterations to transcription factors involved in myeloid differentiation, IFN-α signaling, activator protein-1 (AP1) and cAMP responsive element binding protein/activation transcription factor (CREB/ATF) pathways, which were derived primarily from monocytes and plasmacytoid dendritic cells. IFN-α-treated patients with high depression/fatigue scores demonstrated up-regulation of genes bearing promoter motifs for transcription factors involved in myeloid differentiation, IFN-α and AP1 signaling, and reduced prevalence of motifs for CREB/ATF, which has been implicated in major depression.

CONCLUSIONS

Depression and fatigue during chronic IFN-α administration were associated with alterations in the expression (OAS2) and transcriptional control (CREB/ATF) of genes linked to behavioral disorders including CFS and major depression, further supporting an immune contribution to these diseases.

Early intervention to reduce the global health and economic burden of major depression in older adults

Randomized trials for selective and indicated prevention of depression in both mixed-aged and older adult samples, conducted in high-income countries (HICs), show that rates of incident depression can be reduced by 20-25% over 1-2 years through the use of psychoeducational and psychological interventions designed to increase protective factors. Recurrence of major depression can also be substantially reduced through both psychological and psychopharmacological strategies. Additional research is needed, however, to address the specific issues of depression prevention in older adults in low- and middle-income countries (LMICs). The growing number of older adults globally, as well as workforce issues and the expense of interventions, makes it important to develop rational, targeted, and cost-effective risk-reduction strategies. In our opinion, one strategy to address these issues entails the use of lay health counselors (LHCs), a form of task shifting already shown to be effective in the treatment of common mental disorders in LMICs. We suggest in this review that the time is right for research into the translation of depression-prevention strategies for use in LMICs.

Identification of proteomic signatures associated with depression and psychotic depression in post-mortem brains from major depression patients

Major depressive disorder (MDD) is a leading cause of disability worldwide and results tragically in the loss of almost one million lives in Western societies every year. This is due to poor understanding of the disease pathophysiology and lack of empirical medical tests for accurate diagnosis or for guiding antidepressant treatment strategies. Here, we have used shotgun proteomics in the analysis of post-mortem dorsolateral prefrontal cortex brain tissue from 24 MDD patients and 12 matched controls. Brain proteomes were pre-fractionated by gel electrophoresis and further analyzed by shotgun data-independent label-free liquid chromatography-mass spectrometry. This led to identification of distinct proteome fingerprints between MDD and control subjects. Some of these differences were validated by Western blot or selected reaction monitoring mass spectrometry. This included proteins associated with energy metabolism and synaptic function and we also found changes in the histidine triad nucleotide-binding protein 1 (HINT1), which has been implicated recently in regulation of mood and behavior. We also found differential proteome profiles in MDD with (n=11) and without (n=12) psychosis. Interestingly, the psychosis fingerprint showed a marked overlap to changes seen in the brain proteome of schizophrenia patients. These findings suggest that it may be possible to contribute to the disease understanding by distinguishing different subtypes of MDD based on distinct brain proteomic profiles.

Severe depression, suicide attempts, and ideation during the use of interferon beta by patients with multiple sclerosis

BACKGROUND

Interferon (IFN) beta is a safe and efficient drug for treating multiple sclerosis (MS). It is widely accepted that previously depressed patients may get worse when using IFN-beta. There are few reports on the association of IFN-beta and severe depression among patients without previous psychiatric history.

METHODS

Discussion of a case of a patient with MS who developed severe depression and attempted suicide while using IFN-beta encouraged us to review the subject. A group of neurologists in Brazil retrospectively gathered together their similar cases for the present paper.

RESULTS

The present paper reports on 11 cases of severe depression with suicide attempts or ideation among patients with MS who were using IFN-beta. These patients had no previous history of any psychiatric disease. Nine patients developed the symptoms over a relatively short period (4 months, on average). Two patients developed severe depression after more than 1 year of treatment with IFN-beta. Phobic, aggressive, behavioral, psychotic, and manic symptoms also were observed in these patients, thus suggesting the existence of a complex mood-behavior disorder associated with this drug. Interferon beta withdrawal led to complete remission of symptoms. The Naranjo algorithm established a highly probable association between IFN-beta and this adverse reaction in these patients.

CONCLUSIONS

Although uncommon, severe depression with suicide ideation or attempts may be observed during treatment of MS with IFN-beta. This association should not discourage the use of this drug, but physicians need to be aware of this possible adverse event from IFN-beta.

Depression: a repair response to stress-induced neuronal microdamage that can grade into a chronic neuroinflammatory condition?

Depression is a major contributor to the global burden of disease and disability, yet it is poorly understood. Here we review data supporting a novel theoretical model for the biology of depression. In this model, a stressful life event leads to microdamage in the brain. This damage triggers an injury repair response consisting of a neuroinflammatory phase to clear cellular debris and a spontaneous tissue regeneration phase involving neurotrophins and neurogenesis. During healing, released inflammatory mediators trigger sickness behavior and psychological pain via mechanisms similar to those that produce physical pain during wound healing. The depression remits if the neuronal injury repair process resolves successfully. Importantly, however, the acute psychological pain and neuroinflammation often transition to chronicity and develop into pathological depressive states. This hypothesis for depression explains substantially more data than alternative models, including why emerging data show that analgesic, anti-inflammatory, pro-neurogenic and pro-neurotrophic treatments have antidepressant effects. Thus, an acute depressive episode can be conceptualized as a normally self-limiting but highly error-prone process of recuperation from stress-triggered neuronal microdamage.

Management of Psychiatric Disease in Hepatitis C Treatment Candidates

Depression and other influences on mental health can impact antiviral response rates during chronic hepatitis C treatment, the quality of life for these patients, and the risk for adverse outcomes such as suicide. Enhanced treatment outcomes for patients who are receiving interferon-α requires 1) addressing preexisting mental health problems, 2) alleviating psychiatric conditions that emerge during treatment, and 3) prediction and prevention of these conditions. Accumulating evidence indicates that these three goals are feasible. Collaborative involvement of psychiatric management may often be critical in this regard.