Association of major depressive disorder with serum myeloperoxidase and other markers of inflammation: a twin study

Sex differences in the inflammation-depression link: A systematic review and meta-analysis

Major Depressive Disorder (MDD) is a heterogeneous disorder that affects twice as many women than men. Precluding advances in more tailored and efficacious treatments for depression is the lack of reliable biomarkers. While depression is linked to elevations in inflammatory immune system functioning, this relationship is not evident among all individuals with depression and may vary based on symptom subtypes and/or sex. This systematic review and meta-analysis examined whether inflammatory immune peripheral markers of depression are sex-specific. PRISMA guidelines were followed for the systematic review, and a comprehensive search strategy that identified studies from PubMed and PsycInfo was applied. Studies were included if they reported C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor (TNF)-α and/or IL-1β for males and/or females among depressed and healthy adults. We identified 23 studies that satisfied these inclusion criteria. Random-effects meta-analysis models were fit, and measures of association were summarized between levels of circulating markers of inflammation in depressed and healthy males and females. Sex-based analyses revealed elevated levels of CRP among females with depression (Cohen's d = 0.19) relative to their healthy counterparts (p = 0.02), an effect not apparent among males (Cohen's d = -0.01). Similarly, levels of IL-6 were increased among females with depression compared to healthy controls (Cohen's d = 0.51; p = 0.04), but once again this was not found among males (Cohen's d = 0.16). While TNF-α levels were elevated among individuals with depression compared to controls (p = 0.01), no statistically significant sex differences were found. The meta-analysis for IL-1β resulted in only three articles, and thus, results are presented in the supplemental section. This meta-analysis advances our understanding of the unique involvement of inflammatory biomarkers in depression among men and women, which may help inform more tailored sex-specific treatment approaches in the future.

The interplay between polygenic score for tumor necrosis factor-α, brain structural connectivity, and processing speed in major depression

Reduced processing speed is a core deficit in major depressive disorder (MDD) and has been linked to altered structural brain network connectivity. Ample evidence highlights the involvement of genetic-immunological processes in MDD and specific depressive symptoms. Here, we extended these findings by examining associations between polygenic scores for tumor necrosis factor-α blood levels (TNF-α PGS), structural brain connectivity, and processing speed in a large sample of MDD patients. Processing speed performance of n = 284 acutely depressed, n = 177 partially and n = 198 fully remitted patients, and n = 743 healthy controls (HC) was estimated based on five neuropsychological tests. Network-based statistic was used to identify a brain network associated with processing speed. We employed general linear models to examine the association between TNF-α PGS and processing speed. We investigated whether network connectivity mediates the association between TNF-α PGS and processing speed. We identified a structural network positively associated with processing speed in the whole sample. We observed a significant negative association between TNF-α PGS and processing speed in acutely depressed patients, whereas no association was found in remitted patients and HC. The mediation analysis revealed that brain connectivity partially mediated the association between TNF-α PGS and processing speed in acute MDD. The present study provides evidence that TNF-α PGS is associated with decreased processing speed exclusively in patients with acute depression. This association was partially mediated by structural brain connectivity. Using multimodal data, the current findings advance our understanding of cognitive dysfunction in MDD and highlight the involvement of genetic-immunological processes in its pathomechanisms.

Heart Rate Variability, Deceleration Capacity of Heart Rate, and Death: A Veteran Twins Study

BACKGROUND

Autonomic function can be measured noninvasively using heart rate variability (HRV), which indexes overall sympathovagal balance. Deceleration capacity (DC) of heart rate is a more specific metric of vagal modulation. Higher values of these measures have been associated with reduced mortality risk primarily in patients with cardiovascular disease, but their significance in community samples is less clear.

METHODS AND RESULTS

This prospective twin study followed 501 members from the VET (Vietnam Era Twin) registry. At baseline, frequency domain HRV and DC were measured from 24-hour Holter ECGs. During an average 12-year follow-up, all-cause death was assessed via the National Death Index. Multivariable Cox frailty models with random effect for twin pair were used to examine the hazard ratios of death per 1-SD increase in log-transformed autonomic metrics. Both in the overall sample and comparing twins within pairs, higher values of low-frequency HRV and DC were significantly associated with lower hazards of all-cause death. In within-pair analysis, after adjusting for baseline factors, there was a 22% and 27% lower hazard of death per 1-SD increment in low-frequency HRV and DC, respectively. Higher low-frequency HRV and DC, measured during both daytime and nighttime, were associated with decreased hazard of death, but daytime measures showed numerically stronger associations. Results did not substantially vary by zygosity.

CONCLUSIONS

Autonomic inflexibility, and especially vagal withdrawal, are important mechanistic pathways of general mortality risk, independent of familial and genetic factors.

Biomarkers of Postpartum Depression: A Narrative Review

Postpartum depression (PPD) is a disorder that impairs the formation of the relationship between mother and child, and reduces the quality of life for affected women to a functionally significant degree. Studying markers associated with PPD can help in early detection, prevention, or monitoring treatment. The purpose of this paper is to review biomarkers linked to PPD and to present selected theories on the pathogenesis of the disease based on data from biomarker studies. The complex etiology of the disorder reduces the specificity and sensitivity of markers, but they remain a valuable source of information to help clinicians. The biggest challenge of the future will be to translate high-tech methods for detecting markers associated with postpartum depression into more readily available and less costly ones. Population-based studies are needed to test the utility of potential PPD markers.

Weighing poor immunometabolic health in relatives for severity of affective symptoms: A study of patients with depressive and anxiety disorders and their siblings

BACKGROUND

Affective (i.e. depressive and anxiety) disorders often co-occur with immunometabolic diseases and related biological pathways. Although many large population-based and meta-analytic studies have confirmed this link in community and clinical samples, studies in at-risk samples of siblings of persons with affective disorders are lacking. Furthermore, this somatic-mental co-occurrence may be partially explained by familial clustering of the conditions. First, we examined whether the association between a wide range of immunometabolic diseases and related biomarker based risk-profiles with psychological symptoms replicates in at-risk siblings of probands with affective disorders. Second, leveraging on a sibling-pair design, we disentangled and quantified the effect of probands' immunometabolic health on siblings' psychological symptoms and on the association between immunometabolic health and these symptoms in siblings.

METHODS

The sample included 636 participants (Mage = 49.7; 62.4% female) from 256 families, each including a proband with lifetime depressive and/or anxiety disorders and at least one of their sibling(s) (N = 380 proband-sibling pairs). Immunometabolic health included cardiometabolic and inflammatory diseases, body mass index (BMI), and composite metabolic (based on the five metabolic syndrome components) and inflammatory (based on interleukin-6 and C-reactive protein) biomarker indices. Overall affective symptoms and specific atypical, energy-related depressive symptoms were derived from self-report questionnaires. Mixed-effects analyses were used to model familial clustering.

RESULTS

In siblings, inflammatory disease (γ = 0.25, p = 0.013), higher BMI (γ = 0.10, p = 0.033) and metabolic index (γ = 0.28, p < 0.001) were associated with higher affective symptoms, with stronger associations for atypical, energy-related depressive symptoms (additionally associated with cardiometabolic disease; γ = 0.56, p = 0.048). Immunometabolic health in probands was not independently associated with psychological symptoms in siblings nor did it moderate the association between immunometabolic health and psychological symptoms estimated in siblings.

CONCLUSIONS

Our findings demonstrate that the link between later life immunometabolic health and psychological symptoms is consistently present also in adult siblings at high risk for affective disorders. Familial clustering did not appear to have a substantial impact on this association. Instead, individual lifestyle, rather than familial factors, may have a relatively higher impact in the clustering of later life immunometabolic conditions with psychological symptoms in at-risk adult individuals. Furthermore, results highlighted the importance of focusing on specific depression profiles when investigating the overlap with immunometabolic health.

Exploring brain glutathione and peripheral blood markers in posttraumatic stress disorder: a combined [1H]MRS and peripheral blood study

Introduction

Oxidative stress has been implicated in psychiatric disorders, including posttraumatic stress disorder (PTSD). Currently, the status of glutathione (GSH), the brain's most abundant antioxidant, in PTSD remains uncertain. Therefore, the current study investigated brain concentrations of GSH and peripheral concentrations of blood markers in individuals with PTSD vs. Healthy Controls (HC).

Methods

GSH spectra was acquired in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC) using MEGA-PRESS, a J-difference-editing acquisition method. Peripheral blood samples were analyzed for concentrations of metalloproteinase (MMP)-9, tissue inhibitors of MMP (TIMP)-1,2, and myeloperoxidase (MPO).

Results

There was no difference in GSH between PTSD and HC in the ACC (n = 30 PTSD, n = 20 HC) or DLPFC (n = 14 PTSD, n = 18 HC). There were no group differences between peripheral blood markers (P > 0.3) except for (non-significantly) lower TIMP-2 in PTSD. Additionally, TIMP-2 and GSH in the ACC were positively related in those with PTSD. Finally, MPO and MMP-9 were negatively associated with duration of PTSD.

Conclusions

We do not report altered GSH concentrations in the ACC or DLPFC in PTSD, however, systemic MMPs and MPO might be implicated in central processes and progression of PTSD. Future research should investigate these relationships in larger sample sizes.

Exploring the bi-directional relationship and shared genes between depression and stroke via NHANES and bioinformatic analysis

Background: Stroke and depression are the two most common causes of disability worldwide. Growing evidence suggests a bi-directional relationship between stroke and depression, whereas the molecular mechanisms underlying stroke and depression are not well understood. The objectives of this study were to identify hub genes and biological pathways related to the pathogenesis of ischemic stroke (IS) and major depressive disorder (MDD) and to evaluate the infiltration of immune cells in both disorders. Methods: Participants from the United States National Health and Nutritional Examination Survey (NHANES) 2005-2018 were included to evaluate the association between stroke and MDD. Two differentially expressed genes (DEGs) sets extracted from GSE98793 and GSE16561 datasets were intersected to generate common DEGs, which were further screened out in cytoHubba to identify hub genes. GO, KEGG, Metascape, GeneMANIA, NetworkAnalyst, and DGIdb were used for functional enrichment, pathway analysis, regulatory network analysis, and candidate drugs analysis. ssGSEA algorithm was used to analyze the immune infiltration. Results: Among the 29706 participants from NHANES 2005-2018, stroke was significantly associated with MDD (OR = 2.79,95% CI:2.26-3.43, p < 0.0001). A total of 41 common upregulated genes and eight common downregulated genes were finally identified between IS and MDD. Enrichment analysis revealed that the shared genes were mainly involved in immune response and immune-related pathways. A protein-protein interaction (PPI) was constructed, from which ten (CD163, AEG1, IRAK3, S100A12, HP, PGLYRP1, CEACAM8, MPO, LCN2, and DEFA4) were screened. In addition, gene-miRNAs, transcription factor-gene interactions, and protein-drug interactions coregulatory networks with hub genes were also identified. Finally, we observed that the innate immunity was activated while acquired immunity was suppressed in both disorders. Conclusion: We successfully identified the ten hub shared genes linking the IS and MDD and constructed the regulatory networks for them that could serve as novel targeted therapy for the comorbidities.

Chronic Fatigue, Depression and Anxiety Symptoms in Long COVID Are Strongly Predicted by Neuroimmune and Neuro-Oxidative Pathways Which Are Caused by the Inflammation during Acute Infection

BACKGROUND

Long-term coronavirus disease 2019 (long COVID) is associated with physio-somatic (chronic fatigue syndrome and somatic symptoms) and affective (depression and anxiety) symptoms. The severity of the long COVID physio-affective phenome is largely predicted by increased peak body temperature (BT) and lowered oxygen saturation (SpO2) during the acute infectious phase. This study aims to delineate whether the association of BT and SpO2 during the acute phase and the long COVID physio-affective phenome is mediated by neurotoxicity (NT) resulting from activated immune-inflammatory and oxidative stress pathways.

METHODS

We recruited 86 patients with long COVID (3-4 months after the acute phase) and 39 healthy controls and assessed serum C-reactive protein (CRP), caspase 1, interleukin (IL) 1β, IL-18, IL-10, myeloperoxidase (MPO), advanced oxidation protein products (AOPPs), total antioxidant capacity (TAC), and calcium (Ca), as well as peak BT and SpO2 during the acute phase.

RESULTS

Cluster analysis revealed that a significant part (34.9%) of long COVID patients (n = 30) show a highly elevated NT index as computed based on IL-1β, IL-18, caspase 1, CRP, MPO, and AOPPs. Partial least squares analysis showed that 61.6% of the variance in the physio-affective phenome of long COVID could be explained by the NT index, lowered Ca, and peak BT/SpO2 in the acute phase and prior vaccinations with AstraZeneca or Pfizer. The most important predictors of the physio-affective phenome are Ca, CRP, IL-1β, AOPPs, and MPO.

CONCLUSION

The infection-immune-inflammatory core of acute COVID-19 strongly predicts the development of physio-affective symptoms 3-4 months later, and these effects are partly mediated by neuro-immune and neuro-oxidative pathways.

Myeloperoxidase as a Potential Biomarker of Acute-Myocardial-Infarction-Induced Depression and Suppression of the Innate Immune System

While myeloperoxidase (MPO) serves as an indicator of both neutrophil and innate-immune-system function, the potential suppression of the innate immune system in patients with acute myocardial infarction (AMI)-induced depression might be evidenced by a decrease in MPO serum levels. The aim of this prospective study was to (1) determine whether serum concentrations of MPO vary immediately and 6 months after AMI and (2) to investigate whether MPO concentrations at the time of the AMI are significant predictors of AMI-induced depression and the depression-associated suppression of the innate immune system. A total of 109 AMI patients were assessed with the Hamilton Depression Scale (HAMD-17) immediately after admission to the hospital and 6 months later. The MPO status was assessed with serum samples, which were also collected immediately and 6 months after AMI. The depressive patients showed significantly lower MPO blood levels immediately and 6 months after the AMI compared to the patients without depression (ANCOVA: MPO (depression) F = 4.764, df = 1, p = 0.031). The baseline MPO was observed as a significant predictor (p = 0.027) of AMI-induced depression 6 months after AMI. MPO is a potential biomarker for AMI-induced depression, indicating a depression-associated suppression of the innate immune system.

Effects of Xinkeshu tablets on coronary heart disease patients combined with anxiety and depression symptoms after percutaneous coronary intervention: A meta-analysis

BACKGROUND

Xinkeshu tablets (XKS), a well-known Chinese patent drug, have been administered to coronary heart disease (CHD) patients with anxiety and depression after percutaneous coronary intervention (PCI).

PURPOSE

This meta-analysis aimed to systematically evaluate the clinical effects of XKS for treating CHD patients with anxiety and depression after PCI.

METHODS

Randomized controlled trials (RCTs) about XKS alone or combined with conventional drugs for the treatment of CHD patients with anxiety and depression after PCI were retrieved from 7 databases (MEDLINE, EMBASE, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP) Database, Chinese Biomedical Database (CBM) and Wanfang Database) through November 2021. First, the studies were reviewed and screened by two independent assessors according to the eligibility criteria. Second, the methodological quality of the eligible studies was evaluated based on the Cochrane Collaboration's tool for assessing the risk of bias. Subsequently, meta-analysis was performed by using RevMan 5.4 software, and publication bias was evaluated by Stata 12.0 software. Finally, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was applied to rate the quality of the evidence.

RESULTS

In total, 11 clinical RCTs involving 1000 patients were included in this study. This meta-analysis found that compared with conventional treatment alone, XKS combined with conventional treatment significantly improved the anxiety scale scores (SMD = -1.97, 95% CI -3.13 to -0.82; p = 0.0008; I² = 98%), the depression scores (SMD = -2.80, 95% CI -4.49 to -1.10; p = 0.001; I² = 98%), the scores on the Medical Outcomes Study 36 Item Short Form Health Survey (SF36) (MD = 11.22, 95% CI 4.19 to 18.26; p =0.002; I² = 95%) and the blood lipid levels of total cholesterol (TC) (MD = -0.38, 95% CI -0.62 to -0.13; p = 0.003; I² = 0%) and triglyceride (TG) (MD = -0.31, 95% CI -0.46 to -0.17; p < 0.0001; I² =  0%).

CONCLUSION

The current evidence suggests that XKS might benefit CHD patients experiencing anxiety and depression after PCI by helping to improve their depression symptoms, TC and TG blood lipid levels. However, due to insufficient methodological quality of the studies, several risks of bias and inadequate reporting of the clinical data, more rigorous, multicenter, sufficient-sample and double-blind randomized clinical trials are warranted.

TwinEQTL: Ultra Fast and Powerful Association Analysis for eQTL and GWAS in Twin Studies

We develop a computationally efficient alternative, TwinEQTL, to a linear mixed-effects model (LMM) for twin genome-wide association study (GWAS) data. Instead of analyzing all twin samples together with LMM, TwinEQTL first splits twin samples into two independent groups on which multiple linear regression analysis can be validly performed separately, followed by an appropriate meta-analysis-like approach to combine the two non-independent test results. Through mathematical derivations, we prove the validity of TwinEQTL algorithm and show that the correlation between two dependent test statistics at each single-nucleotide polymorphism (SNP) are independent of its minor allele frequency (MAF). Thus the correlation is constant across all SNPs. Through simulations, we show empirically that TwinEQTL has well controlled type I error with negligible power loss compared to the gold-standard linear mixed effects models. To accommodate eQTL analysis with twin subjects, we further implement TwinEQTL into a R package with much improved computational efficiency. Our approaches provide a significant leap in terms of computing speed for GWAS and eQTL analysis with twin samples.

Expression of PON1, PON2, PON3 and MPO Genes in Patients with Depressive Disorders

Background: Taking into account the role of oxidative stress in neurodegeneration, we sought to evaluate the expression of genes for select enzymes with antioxidant properties (paraoxonases PON1, PON2 and PON3 and myeloperoxidase MPO) at the mRNA and protein levels in patients with depressive disorders. We further sought to determine the impact of oxidative stress in the etiopathogenesis of this group of mood disorders. Methods: A total of 290 subjects (190 depressed patients, 100 healthy controls) took part in the study. Sociodemographic and clinical data were collected. The severity of depressive symptoms was assessed using the Hamilton Depression Rating Scale (HDRS). Venous blood was collected. RT-PCR was used to assess gene expression at the mRNA level, while enzyme-linked immunosorbent assay (ELISA) was used to assess gene expression at the protein level. Results: The expression of the PON2 and PON3 genes at the protein level was significantly higher in depressive patients than in healthy controls. mRNA expression of the PON1, PON2 and PON3 genes was slightly higher in patients with depressive disorders than in the control group, however, this relationship was not statistically significant. On the other hand, the expression of the MPO gene at both mRNA and protein levels was significantly lower in patients with depressive disorder than in the control group. Conclusions: Our results are not in agreement with many studies on enzymes involved in maintaining oxidative balance. Our findings may not support the utility of paraoxonases (PON) or myeloperoxidase (MPO) as promising biomarker candidates of depression pending larger and well controlled studies.

The mechanistic and prognostic implications of heart rate variability analysis in patients with cirrhosis

Chronic liver damage leads to scarring of the liver tissue and ultimately a systemic illness known as cirrhosis. Patients with cirrhosis exhibit multi-organ dysfunction and high mortality. Reduced heart rate variability (HRV) is a hallmark of cirrhosis, reflecting a state of defective cardiovascular control and physiological network disruption. Several lines of evidence have revealed that decreased HRV holds prognostic information and can predict survival of patients independent of the severity of liver disease. Thus, the aim of this review is to shed light on the mechanistic and prognostic implications of HRV analysis in patients with cirrhosis. Notably, several studies have extensively highlighted the critical role systemic inflammation elicits in conferring the reduction in patients' HRV. It appears that IL-6 is likely to play a central mechanistic role, whereby its levels also correlate with manifestations, such as autonomic neuropathy and hence the partial uncoupling of the cardiac pacemaker from autonomic control. Reduced HRV has also been reported to be highly correlated with the severity of hepatic encephalopathy, potentially through systemic inflammation affecting specific brain regions, involved in both cognitive function and autonomic regulation. In general, the prognostic ability of HRV analysis holds immense potential in improving survival rates for patients with cirrhosis, as it may indeed be added to current prognostic indicators, to ultimately increase the accuracy of selecting the recipient most in need of liver transplantation. However, a network physiology approach in the future is critical to delineate the exact mechanistic basis by which decreased HRV confers poor prognosis.

Peroxiredoxin 6 Overexpression Induces Anxiolytic and Depression-Like Behaviors by Regulating the Serotonergic Pathway in Mice

Peroxiredoxin 6 (PRDX6) is a bifunctional protein with both glutathione peroxidase and calcium-independent phospholipase activity. Recently, we reported that PRDX6 plays an important role in dopaminergic neurodegeneration in Parkinson's disease. However, the relationship between PRDX6 function and emotional behavior remains elusive. In the present study, we examined depression- and anxiety-like behaviors in PRDX6-overexpressing transgenic (PRDX6-Tg) mice using the forced swim test, tail suspension test, open field paradigm, and elevated plus-maze. PRDX6-Tg mice exhibited depression-like behaviors and low anxiety. In particular, female PRDX6-Tg mice exhibited anxiolytic behavior in the open field test. Furthermore, the serotonin content in the cortex and 5-hydroxytryptophan-induced head twitch response were both reduced in PRDX6-Tg mice. Interestingly, levels of dopa decarboxylase expression in the cortex were decreased in male PRDX6-Tg mice but not in female mice. Our findings provide novel insights into the role of PRDX6 in 5-HT synthesis and suggest that PRDX6 overexpression can induce depression-like behaviors via downregulation of the serotonergic neuronal system.

Oxidative and Nitrosative Stress in Major Depressive Disorder: A Case Control Study

Introduction: The role of increased oxidative stress and alterations to the nitric oxide (NO) pathway have been implicated in major depressive disorder (MDD). The two pathways interact closely with each other but have not been studied simultaneously in MDD. This study aimed to assess and compare the levels of oxidative and nitrosative stress in the neutrophils (PMNs) of drug-naive MDD patients and their first-degree relatives. Methods: 29 drug-naive MDD patients and 27 healthy first-degree relatives and healthy controls aged 18–45 years were included in this study. An assessment of the levels of reactive oxygen species (ROS), nitrites, neuronal NO synthase (nNOS), and myeloperoxidase in PMNs, and cortisol in serum was carried out. Results: Compared to healthy controls, the generation of free radicals, myeloperoxidase activity, and nNOS mRNA expression in PMNs, and cortisol level in serum were significantly higher in drug-naive depression patients. Indeed, increased levels of myeloperoxidase and serum cortisol were also noted in first-degree relatives. The total nitrite content in the PMNs and plasma however was significantly lower in both patients and first-degree relatives. Interestingly, a positive correlation was established in the ROS levels in the PMNs, plasma and neutrophil nitrite, and the serum cortisol level between MDD patients and their first-degree relatives. Conclusion: The results of this study contribute towards a better understanding of the familial association of depressive disorder, and demonstrate for the first time that neutrophil ROS/RNS, plasma nitrite, and serum cortisol levels are positively correlated between MDD patients and their first-degree relatives. However, further studies in larger, more diverse samples are needed to extend these pathways as potential biomarkers to identify persons at high risk for psychopathology at an early stage.

Combination of electroconvulsive stimulation with ketamine or escitalopram protects the brain against inflammation and oxidative stress induced by maternal deprivation and is critical for associated behaviors in male and female rats

This study aimed at evaluating the treatment effects with ketamine, electroconvulsive stimulation (ECS), escitalopram, alone or in combination in adult rats of both sexes, subjected to the animal model of maternal deprivation (MD). All groups were subjected to the forced swimming test (FST), splash and open field tests. The prefrontal cortex (PFC), hippocampus and serum were collected to analyze oxidative stress and inflammatory parameters. MD induced depressive-like behavior in the FST test in males and reduced grooming time in male and female rats. The treatments alone or combined reversed depressive and anhedonic behavior in females. In males, all treatments increased grooming time, except for ECS + escitalopram + ketamine. MD increased lipid peroxidation and protein carbonylation, nitrite/nitrate concentration and myeloperoxidase activity in the PFC and hippocampus of males and females. However, the treatment's response was sex dependent. Catalase activity decreased in the PFC of males and the PFC and hippocampus of females, and most treatments were not able to reverse it. MD increased the inflammation biomarkers levels in the PFC and hippocampus of males and females, and most treatments were able to reverse this increase. In all groups, a reduction in the interleukin-10 levels in the PFC and hippocampus of female and male rats was observed. Our study shows different responses between the sexes in the patterns evaluated and reinforces the use of the gender variable as a biological factor in MDD related to early stress and in the response of the therapeutic strategies used.

The Reactive Species Interactome in the Brain

Significance: Redox pioneer Helmut Sies attempted to explain reactive species' challenges faced by organelles, cells, tissues, and organs via three complementary definitions: (i) oxidative stress, that is, the disturbance in the prooxidant-antioxidant defense balance in favor of the prooxidants; (ii) oxidative eustress, the low physiological exposure to prooxidants; and (iii) oxidative distress, the supraphysiological exposure to prooxidants. Recent Advances: Identification, concentration, and interactions are the most important elements to improve our understanding of reactive species in physiology and pathology. In this context, the reactive species interactome (RSI) is a new multilevel redox regulatory system that identifies reactive species families, reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species, and it integrates their interactions with their downstream biological targets. Critical Issues: We propose a united view to fully combine reactive species identification, oxidative eustress and distress, and the RSI system. In this view, we also propose including the forgotten reactive carbonyl species, an increasingly rediscovered reactive species family related to the other reactive families, and key enzymes within the RSI. We focus on brain physiology and pathology to demonstrate why this united view should be considered. Future Directions: More studies are needed for an improved understanding of the contributions of reactive species through their identification, concentration, and interactions, including in the brain. Appreciating the RSI in its entirety should unveil new molecular players and mechanisms in physiology and pathology in the brain and elsewhere.

Inflammatory cytokines, cognition, and response to antidepressant treatment in patients with major depressive disorder

BACKGROUND

Inflammation and cognition are related to major depressive disorder (MDD), but the role in treatment response remains unclear. In this study, we investigated correlation between inflammatory cytokines and cognition in MDD patients treated with antidepressant medication.

METHODS

The participants were 149 MDD patients. Cytokines before therapy, cognitive assessments and severity of depression before and after therapy were tested. Logistic regression was used to explore underlying risks treatment response.

RESULTS

There were significant differences in smoking, alcohol drinking, and Stroop Color Test(SCT), Stroop Color-Word Test (SCWT), and Continuous Performance Test(CPT) scores between response group (RG) and non-response group (NRG) at baseline. Performance of patients in RG improved more in Brief Assessment of Cognition in Schizophrenia (BACS), Color Trial Test-I (CTT-I), SCT and SCWT after treatment. Levels of baseline IL-18 were associated with baseline learning and memory, and executive function. Treatment response was associated with drinking, performance of CPT and SCT.

CONCLUSION

MDD patients with different treatment responses have different cognitive defects, especially in speed of processing and executive function. Expression of cytokines is associated with cognition and may influence treatment response. Better speed of processing and executive function, and poorer attention at baseline may respond better to antidepressant treatment.

Plasma homocysteine concentrations and depression: A twin study

Background

Homocysteine is an amino acid formed during metabolism of the essential amino acid methionine that plays an important role in energy metabolism and neurotransmitter synthesis. High levels of homocysteine have been linked to both depression and cardiovascular disease, however studies of depression have not always been consistent, possibly related to differences in methodology among studies. The study of twins in clinical research can be useful in controlling for confounding factors. The purpose of this study was to assess the relationship between depression and plasma homocysteine in a study of twins.

Methods

Homocysteine concentration was assessed in twins (N = 202) from the Vietnam Era Twin Registry, including twin pairs discordant for the diagnosis of Major Depressive Disorder (MDD) and twin pairs without MDD. Self reported depressive symptom levels were also measured as a continous variable using the Beck Depression Inventory (BDI).

Results

The average homocysteine concentration was 7.9 μmol/L (2.1 μmol/L SD, range of 2.0-17.1 μmol/L). There were no within twin pair differences in homocysteine concentration within twin pairs discordant for MDD and within twin pairs that differed for BDI score. There was a significant pair-level relationship between depressive symptoms as measured by mean BDI score and homocysteine concentration, such that the higher the mean BDI score of the twin pair, the higher the mean homocystein of the pair (p < .001). Every 10 point increase in BDI score was associated with an 0.8 μmol/L increase in homocysteine concentration at the pair level.

Conclusions

These findings are not consistent with a causal role for elevated homocysteine in the development of depression, but rather point to familial confounding or other factors that are shared by twin brothers and that contribute to both depression and homocysteine levels.

Sex differences on the behavior and oxidative stress after ketamine treatment in adult rats subjected to early life stress

This study aimed to evaluate the effects of ketamine, on behavioral parameters, oxidative stress, and inflammation in the brain of male and female rats submitted to the animal model of maternal deprivation (MD). Wistar rats were deprived of maternal care in the first 10 days of life (three hours daily). As adults, male and female rats were divided: control + saline deprived + saline and deprived + ketamine (15 mg/kg). The behavior was evaluated through the open field and forced swimming tests. Then brain was removed for analysis of oxidative damage, the activity of superoxide dismutase (SOD), catalase (CAT), and myeloperoxidase (MPO) activity, and levels of interleukin-6 (IL-6). MD induced depressive behavior in males and ketamine reversed these changes. MD induced an increase in lipid peroxidation in males and females; ketamine reversed these effects in males. Protein carbonylation was increased in males and females, with ketamine decreasing such effects. The concentration of nitrite/nitrate increased in males and females, whereas ketamine decreased this in the PFC of males. SOD and CAT activities were decreased in male and female deprived groups and deprived groups treated with ketamine. MPO activity and IL-6 levels increased in males subjected to MD and ketamine reversed this effect. The results suggest that stressful events in early life can induce behavioral, neuroimmune changes, and oxidative stress, however, such effects depend on sex and brain area. Ketamine presents anti-inflammatory and antioxidant properties and could be considered an alternative for individuals who are resistant to classical treatments.

The role of high-density lipoprotein cholesterol, apolipoprotein A and paraoxonase-1 in the pathophysiology of neuroprogressive disorders

Lowered high-density lipoprotein (HDL) cholesterol has been reported in major depressive disorder, bipolar disorder, first episode of psychosis, and schizophrenia. HDL, its major apolipoprotein component, ApoA1, and the antioxidant enzyme paraoxonase (PON)1 (which is normally bound to ApoA1) all have anti-atherogenic, antioxidant, anti-inflammatory, and immunomodulatory roles, which are discussed in this paper. The paper details the pathways mediating the anti-inflammatory effects of HDL, ApoA1 and PON1 and describes the mechanisms leading to compromised HDL and PON1 levels and function in an environment of chronic inflammation. The molecular mechanisms by which changes in HDL, ApoA1 and PON1 might contribute to the pathophysiology of the neuroprogressive disorders are explained. Moreover, the anti-inflammatory actions of ApoM-mediated sphingosine 1-phosphate (S1P) signalling are reviewed as well as the deleterious effects of chronic inflammation and oxidative stress on ApoM/S1P signalling. Finally, therapeutic interventions specifically aimed at improving the levels and function of HDL and PON1 while reducing levels of inflammation and oxidative stress are considered. These include the so-called Mediterranean diet, extra virgin olive oil, polyphenols, flavonoids, isoflavones, pomegranate juice, melatonin and the Mediterranean diet combined with the ketogenic diet.

Transcutaneous vagal nerve stimulation blocks stress-induced activation of Interleukin-6 and interferon-γ in posttraumatic stress disorder: A double-blind, randomized, sham-controlled trial

Posttraumatic stress disorder (PTSD) is a highly disabling condition associated with alterations in multiple neurobiological systems, including increases in inflammatory function. Vagus nerve stimulation (VNS) decreases inflammation, however few studies have examined the effects of non-invasive VNS on physiology in human subjects, and no studies in patients with PTSD. The purpose of this study was to assess the effects of transcutaneous cervical VNS (tcVNS) on inflammatory responses to stress. Thirty subjects with a history of exposure to traumatic stress with (N ​= ​10) and without (N ​= ​20) PTSD underwent exposure to stressful tasks immediately followed by active or sham tcVNS and measurement of multiple biomarkers of inflammation (interleukin-(IL)-6, IL-2, IL-1β, Tumor Necrosis Factor alpha (TNFα) and Interferon gamma (IFNγ) over multiple time points. Stressful tasks included exposure to personalized scripts of traumatic events on day 1, and public speech and mental arithmetic (Mental Stress) tasks on days 2 and 3. Traumatic scripts were associated with a pattern of subjective anger measured with Visual Analogue Scales and increased IL-6 and IFNγ in PTSD patients that was blocked by tcVNS (p ​< ​.05). Traumatic stress had minimal effects on these biomarkers in non-PTSD subjects and there was no difference between tcVNS or sham. No significant differences were seen between groups in IL-2, IL-1β, or TNFα. These results demonstrate that tcVNS blocks behavioral and inflammatory responses to stress reminders in PTSD.

Endothelial dysfunction in neuroprogressive disorders-causes and suggested treatments

BACKGROUND

Potential routes whereby systemic inflammation, oxidative stress and mitochondrial dysfunction may drive the development of endothelial dysfunction and atherosclerosis, even in an environment of low cholesterol, are examined.

MAIN TEXT

Key molecular players involved in the regulation of endothelial cell function are described, including PECAM-1, VE-cadherin, VEGFRs, SFK, Rho GEF TRIO, RAC-1, ITAM, SHP-2, MAPK/ERK, STAT-3, NF-κB, PI3K/AKT, eNOS, nitric oxide, miRNAs, KLF-4 and KLF-2. The key roles of platelet activation, xanthene oxidase and myeloperoxidase in the genesis of endothelial cell dysfunction and activation are detailed. The following roles of circulating reactive oxygen species (ROS), reactive nitrogen species and pro-inflammatory cytokines in the development of endothelial cell dysfunction are then described: paracrine signalling by circulating hydrogen peroxide, inhibition of eNOS and increased levels of mitochondrial ROS, including compromised mitochondrial dynamics, loss of calcium ion homeostasis and inactivation of SIRT-1-mediated signalling pathways. Next, loss of cellular redox homeostasis is considered, including further aspects of the roles of hydrogen peroxide signalling, the pathological consequences of elevated NF-κB, compromised S-nitrosylation and the development of hypernitrosylation and increased transcription of atherogenic miRNAs. These molecular aspects are then applied to neuroprogressive disorders by considering the following potential generators of endothelial dysfunction and activation in major depressive disorder, bipolar disorder and schizophrenia: NF-κB; platelet activation; atherogenic miRs; myeloperoxidase; xanthene oxidase and uric acid; and inflammation, oxidative stress, nitrosative stress and mitochondrial dysfunction.

CONCLUSIONS

Finally, on the basis of the above molecular mechanisms, details are given of potential treatment options for mitigating endothelial cell dysfunction and activation in neuroprogressive disorders.

Diet, Stress and Mental Health

Introduction: There has long been an interest in the effects of diet on mental health, and the interaction of the two with stress; however, the nature of these relationships is not well understood. Although associations between diet, obesity and the related metabolic syndrome (MetS), stress, and mental disorders exist, causal pathways have not been established. Methods: We reviewed the literature on the relationship between diet, stress, obesity and psychiatric disorders related to stress. Results: Diet and obesity can affect mood through direct effects, or stress-related mental disorders could lead to changes in diet habits that affect weight. Alternatively, common factors such as stress or predisposition could lead to both obesity and stress-related mental disorders, such as depression and posttraumatic stress disorder (PTSD). Specific aspects of diet can lead to acute changes in mood as well as stimulate inflammation, which has led to efforts to assess polyunsaturated fats (PUFA) as a treatment for depression. Bidirectional relationships between these different factors are also likely. Finally, there has been increased attention recently on the relationship between the gut and the brain, with the realization that the gut microbiome has an influence on brain function and probably also mood and behavior, introducing another way diet can influence mental health and disorders. Brain areas and neurotransmitters and neuropeptides that are involved in both mood and appetite likely play a role in mediating this relationship. Conclusions: Understanding the relationship between diet, stress and mood and behavior could have important implications for the treatment of both stress-related mental disorders and obesity.

Inflammatory markers in depression: A meta-analysis of mean differences and variability in 5,166 patients and 5,083 controls

IMPORTANCE

The magnitude and variability of cytokine alterations in depression are not clear.

OBJECTIVE

To perform an up to date meta-analysis of mean differences of immune markers in depression, and to quantify and test for evidence of heterogeneity in immune markers in depression by conducting a meta-analysis of variability to ascertain whether only a sub-group of patients with depression show evidence of inflammation.

DATA SOURCES

Studies that reported immune marker levels in peripheral blood in patients with depression and matched healthy controls in the MEDLINE database from inception to August 29th 2018 were examined.

STUDY SELECTION

Case-control studies that reported immune marker levels in peripheral blood in patients with depression and healthy controls were selected.

DATA EXTRACTION AND SYNTHESIS

Means and variances (SDs) were extracted for each measure to calculate effect sizes, which were combined using multivariate meta-analysis.

MAIN OUTCOMES AND MEASURES

Hedges g was used to quantify mean differences. Relative variability of immune marker measurements in patients compared with control groups as indexed by the coefficient of variation ratio (CVR).

RESULTS

A total of 107 studies that reported measurements from 5,166 patients with depression and 5,083 controls were included in the analyses. Levels of CRP (g = 0.71; 95%CI: 0.50-0.92; p < 0.0001); IL-3 (g = 0.60; 95%CI: 0.31-0.89; p < 0.0001); IL-6 (g = 0.61; 95%CI: 0.39-0.82; p < 0.0001); IL-12 (g = 1.18; 95%CI: 0.74-1.62; p < 0.0001); IL-18 (g = 1.97; 95%CI: 1.00-2.95; p < 0.0001); sIL-2R (g = 0.71; 95%CI: 0.44-0.98; p < 0.0001); and TNFα (g = 0.54; 95%CI: 0.32-0.76; p < 0.0001) were significantly higher in patients with depression. These findings were robust to a range of potential confounds and moderators. Mean-scaled variability, measured as CVR, was significantly lower in patients with depression for CRP (CVR = 0.85; 95%CI: 0.75-0.98; p = 0.02); IL-12 (CVR = 0.61; 95%CI: 0.46-0.80; p < 0.01); and sIL-2R (CVR = 0.85; 95%CI: 0.73-0.99; p = 0.04), while it was unchanged for IL-3, IL-6, IL-18, and TNF α.

CONCLUSIONS AND RELEVANCE

Depression is confirmed as a pro-inflammatory state. Some of the inflammatory markers elevated in depression, including CRP and IL-12, show reduced variability in patients with depression, therefore supporting greater homogeneity in terms of an inflammatory phenotype in depression. Some inflammatory marker elevations in depression do not appear due to an inflamed sub-group, but rather to a right shift of the immune marker distribution.

Placebo effects and the molecular biological components involved

Pharmacologically inactive substances have been used in medicine for more than 700 years and can trigger beneficial responses in the human body, which is referred to as the placebo effects or placebo responses. This effect is robust enough to influence psychosocial and physiological responses to the placebo and to active treatments in many settings, which has led to increased interest from researchers. In this article, we summarise the history of placebo, the characteristics of placebo effects and recent advancements reported from the studies on placebo effects and highlight placebome studies to identify various molecular biological components associated with placebo effects. Although placebos have a long history, the placebome concept is still in its infancy. Although behavioural, neurobiological and genetic studies have identified that molecules in the dopamine, opioid, serotonin and endocannabinoid systems might be targets of the placebo effect, placebome studies with a no-treatment control (NTC) are necessary to identify whole-genome genetic targets. Although bioinformatics analysis has identified the molecular placebome module, placebome studies with NTCs are also required to validate the related findings.

Peritoneal endometriosis induces time-related depressive- and anxiety-like alterations in female rats: involvement of hippocampal pro-oxidative and BDNF alterations

Endometriosis is a gynecological condition affecting 10% of women in reproductive age. High rates of depression and anxiety are observed in these patients. The mechanisms underlying endometriosis-induced behavioral alterations are still elusive. Animal models provide a useful tool to study the temporal sequence and biological pathways involved in this disease and comorbid states. Here, we sought to characterize time-related behavioral alterations in rats submitted to endometriosis model (EM) induced by peritoneal auto-transplantation of uterine tissues weekly for three weeks. Corticosterone stress reactivity, oxidative stress markers - reduced glutathione (GSH), lipid peroxidation, activity of superoxide dismutase (SOD) and myeloperoxidase (MPO) - and brain-derived-neurotrophic factor (BDNF) levels in the hippocampus were also evaluated. We observed a progressive increase in anxiety-like behavior from 14th to 21st days post-EM. Despair-like behavior was observed from the 14th day post-EM on, while anhedonia and apathetic-like behaviors accompanied by increased corticosterone stress response were detected on 21 days post-EM. Increased pain sensitivity was observed from the 7th day post-EM and was accompanied by increased endometrioma weight. The pro-oxidative alterations, decreased GSH and increased SOD activity were observed on 21 days post-EM, except for lipid peroxidation that was altered from the 14th day. Decreased BDNF also occurred on the 21st day. Therefore, this study demonstrates that EM is related to several features of clinical depression and proposes the contribution of hippocampal oxidative state and neurotrophic support for the emergence of these changes. Our results support the use of this model as a useful tool to test new strategies for endometriosis-related neuropsychiatric symptoms.

Neuroimmune nexus of depression and dementia: Shared mechanisms and therapeutic targets

Dysfunctional immune activity is a physiological component of both Alzheimer's disease (AD) and major depressive disorder (MDD). The extent to which altered immune activity influences the development of their respective cognitive symptoms and neuropathologies remains under investigation. It is evident, however, that immune activity affects neuronal function and circuit integrity. In both disorders, alterations are present in similar immune networks and neuroendocrine signalling pathways, immune responses persist in overlapping neuroanatomical locations, and morphological and structural irregularities are noted in similar domains. Epidemiological studies have also linked the two disorders, and their genetic and environmental risk factors intersect along immune-activating pathways and can be synonymous with one another. While each of these disorders individually contains a large degree of heterogeneity, their shared immunological components may link distinct phenotypes within each disorder. This review will therefore highlight the shared immune pathways of AD and MDD, their overlapping neuroanatomical features, and previously applied, as well as novel, approaches to pharmacologically manipulate immune pathways, in each neurological condition. LINKED ARTICLES: This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc.

Longitudinal association of inflammation with depressive symptoms: A 7-year cross-lagged twin difference study

BACKGROUND

The direction of the association between inflammation and depressive symptoms remains inconsistent. The objective of this study was to evaluate the temporal relationship between inflammation and depressive symptoms, and to assess the role of genetic factors on this association.

METHODS

In this longitudinal cross-lagged twin difference study, we examined 166 (83 pairs) middle-aged male twins recruited from the Vietnam Era Twin Registry, who were assessed at baseline and after 7 years of follow-up. We assayed plasma levels of two inflammatory biomarkers, interleukin-6 (IL-6) and high sensitivity C-reactive protein (CRP) and measured depressive symptoms using the Beck Depression Inventory-II (BDI). To evaluate the direction of the association, we constructed multivariable mixed-effects regression models and calculated standardized beta-coefficients to compare the strength of the within-pair association for both pathways. We then conducted a stratified analysis by zygosity and assessed the associations in monozygotic and dizygotic twin pairs separately.

RESULTS

The 166 twins were 95% white and had a mean (SD) age of 54 (3) years at baseline. The cross-lagged analysis showed significant and positive associations from visit 1 IL-6 to visit 2 BDI across all models (beta-coefficients ranging from 0.18 to 0.22). However, the opposite pathway (visit 1 BDI to visit 2 IL-6) was not significant after adjusting for confounding factors. In contrast, visit 1 BDI was significantly associated with visit 2 CRP in all models (beta-coefficients ranging from 0.23 to 0.33), while the opposite pathway (visit 1 CRP to visit 2 BDI) showed no significant association. When stratifying by zygosity, significant associations from IL-6 to depression were only seen in monozygotic twins, but associations from depression to CRP were more robust in dizygotic twins, which implies that genetic factors may play a role in this association.

CONCLUSIONS

The association between inflammation and depression may be bidirectional. Elevated IL-6 levels are more likely to be a risk factor of depression rather than a consequence, while the opposite may be true for elevated CRP. The biological underpinnings of these bidirectional pathways need further evaluation.

In major affective disorders, early life trauma predict increased nitro-oxidative stress, lipid peroxidation and protein oxidation and recurrence of major affective disorders, suicidal behaviors and a lowered quality of life

Early life trauma (ELT) may increase the risk towards bipolar disorder (BD) and major depression (MDD), disorders associated with activated neuro-oxidative and neuro-nitrosative stress (O&NS) pathways. It has remained elusive whether ELTs are associated with O&NS and which ELTs are associated with distinct affective disorder phenotypes. This case-control study examined patients with BD (n = 68) and MDD (n = 37) and healthy controls (n = 66). The Child Trauma Questionnaire (CTQ) was used to assess specific ELT. We measured malondialdehyde (MDA), lipid hydroperoxides (LOOH), superoxide dismutase (SOD), catalase, advanced oxidation protein products (AOPP); NO metabolites (NOx), paraoxonase 1 activity, zinc, albumin, high density lipoprotein cholesterol and -SH groups and computed z-unit weighted composite scores. Physical neglect significantly predicts higher z-unit weighted composite scores of LOOH+SOD, LOOH+SOD+NOx, LOOH+SOD+NOx + MDA and LOOH+SOD+NOx + AOPP. Sexual abuse was associated with a significantly lower composite score of zinc+albumin+SH. Emotional abuse was associated with severity of depression and anxiety, number of depressive and manic episodes, alcohol and hypnotics use, lifetime suicidal behavior and lowered quality of life. Sexual abuse was associated with an increased risk towards BD, but not MDD. ELT, especially physical neglect, may drive increased (nitro-)oxidative stress coupled with lipid and protein oxidation, which - together with emotional abuse - may play a role in severity of illness, lowered quality of life and MDD. ELTs are also associated with the onset of BD, but this link did not appear to be related to activated O&NS pathways. These novel findings deserve confirmation in prospective studies.

Untargeted metabolomics reveals multiple metabolites influencing smoking-related DNA methylation

AIM

We conducted a joint metabolomic-epigenomic study to identify patterns of epigenetic associations with smoking-related metabolites.

PATIENTS & METHODS

We performed an untargeted metabolome-wide association study of smoking and epigenome-wide association studies of smoking-related metabolites among 180 male twins. We examined the patterns of epigenetic association linked to smoking-related metabolites using hierarchical clustering.

RESULTS

Among 12 annotated smoking-related metabolites identified from a metabolome-wide association study, we observed significant hypomethylation associated with increased level of N-acetylpyrrolidine, cotinine, 5-hydroxycotinine and nicotine and hypermethylation associated with increased level of 8-oxoguanine. Hierarchical clustering revealed common and unique epigenetic-metabolic associations related to smoking.

CONCLUSION

Our study suggested that a joint metabolome-epigenome approach can reveal additional details in molecular responses to the environmental exposure to understand disease risk.

Myeloperoxidase and Neurological Disorder: A Crosstalk

Myeloperoxidase (MPO) is a protein present in azurophilic granules, macrophages, and neutrophils that are released into extracellular fluid (ECF) during inflammation. MPO releases hypochlorous acid (HOCl) and other chlorinated species. It is derived from hydrogen peroxide (H₂O₂) showing response during inflammatory conditions and plays a role in the immune defense against pathogens. MPO may show unwanted effects by indirectly increasing the formation of reactive nitrogen species (RNS), reactive oxygen species (ROS), and tumor necrosis factor alpha (TNF-α) leading to inflammation and oxidative stress. As neuroinflammation is one of the inevitable biological components among most of neurological disorders, MPO and its receptor may be explored as candidates for future clinical interventions. The purpose of this review is to provide an overview of the pathophysiological characteristics of MPO and further explore the possibilities to target it for clinical use. Targeting MPO is promising and may open an avenue to act as a biomarker for diagnosis with defined risk stratification in patients with various neurological disorders.

Perinatal programming of depressive-like behavior by inflammation in adult offspring mice whose mothers were fed polluted eels: Gender selective effects

Several lines of evidence indicate that early-life inflammation may predispose to mental illness, including depression, in later-life. We investigated the impact of perinatal exposure to polluted eels on neonatal, postnatal, and adult brain inflammation, and on the resignation behavior of male and female adult offspring mice. The effects of maternal standard diet (laboratory food) were compared to the same diet enriched with low, intermediate, or highly polluted eels. Brain inflammatory markers including cytokines were assessed in offspring mice on the day of birth (i.e., on the postnatal day-PND 1), upon weaning (PND 21) and at adulthood (PND 100). Plasma myeloperoxidase and corticosterone levels were evaluated at PND 100. Immobility behavior of offspring was assessed in adulthood (i.e., at PNDs 95-100), using the tail suspension and forced swimming tests. Chronic brain inflammation was found in male and female offspring mice compared to controls, as assessed at PNDs 1, 21, and 100. The level of myeloperoxidase was found to be significantly higher in both adult males and females vs. control offspring. However, high corticosterone levels were only found in male offspring mice that were perinatally exposed to eels, suggesting a gender-selective dysregulation of the adult hypothalamic-pituitaryadrenal (HPA) axis. Gender-specific differences were also detected in adulthood in regard to offspring resignation behavior. Thus, compared to controls, males, but not females, whose mothers were fed eels during pregnancy and lactation exhibited a depressive-like behavior in adult age in both behavioral models of depression. Depressive symptoms were more pronounced in male mice perinatally exposed to either intermediate or highly polluted eels than those exposed to only lowly polluted eels. Our results indicate that early-life inflammatory insult is a plausible causative factor that induces the depressive phenotype exhibited by male adult offspring mice, most likely through a gender-specific HPA axis enhanced activation.

Meta-analysis of Plasma Interleukine-6 Levels in Patients with Depressive Disorder

Growing body of evidence suggests that inflammatory processes play an important role in the pathophysiology and the clinical course of depressive disorder, as well as several others major psychiatric and somatic conditions. Interleukin (IL-6), one of the proinflammatory cytokines, has been extensively examined in a number of studies among depressed patients. To assess quantitatively the relationship between depression and IL-6, a systematic review of relevant literature published to October 2009 was performed and relevant data were meta-analysed using random-effects model. A positive association was found (standardized difference in means=1.055, p>0,001), although a significant heterogeneity among studies (Q(15)=141, p<0,001) points to relevance of further subgroup analyses.

Association of ATP6V1B2 rs1106634 with lifetime risk of depression and hippocampal neurocognitive deficits: possible novel mechanisms in the etiopathology of depression

Current understanding and treatment of depression is limited to the monoaminergic theory with little knowledge of the involvement of other cellular processes. Genome-wide association studies, however, implicate several novel single-nucleotide polymorphisms with weak but replicable effects and unclarified mechanisms. We investigated the effect of rs1106634 of the ATPV1B2 gene encoding the vacuolar H+ATPase on lifetime and current depression and the possible mediating role of neuroticism by logistic and linear regression in a white European general sample of 2226 subjects. Association of rs1106634 with performance on frontal (Stockings of Cambridge (SOC)) and hippocampal-dependent (paired associates learning (PAL)) cognitive tasks was investigated in multivariate general linear models in a smaller subsample. The ATP6V1B2 rs1106634 A allele had a significant effect on lifetime but not on current depression. The effect of the A allele on lifetime depression was not mediated by neuroticism. The A allele influenced performance on the PAL but not on the SOC test. We conclude that the effects of variation in the vacuolar ATPase may point to a new molecular mechanism that influences the long-term development of depression. This mechanism may involve dysfunction specifically in hippocampal circuitry and cognitive impairment that characterizes recurrent and chronic depression.

Depression in pregnancy is associated with decreased glutathione peroxidase activity in fetal cord blood

The investigation of fetal cord blood (FCB) during child delivery has created a novel topic in the field of psychiatric research. The umbilical vein receives nutrients and oxygen from the mother's circulation and transports them to the fetal circulation. Investigating fetal cord blood during delivery is beneficial for understanding the fetal environment. Depression in pregnancy is associated with medical and emotional burdens. In this study, we aimed to investigate glutathione peroxidase (Gpx) and myeloperoxidase (MPO) activity in the FCB of depressed mothers and healthy controls. Our study included 45 depressed mothers and 59 healthy controls. The FCB samples were collected from the umbilical vein during delivery. We found that Gpx levels were significantly decreased in the FCB of depressed mothers than healthy controls, medians were 0.14 U/ml and 0.16 U/ml respectively, Z: -3.567 and p < 0.001. MPO levels were similar in both groups, medians were 1.0 U/L and 1.2 U/L respectively, Z: -1.837 and p:0.066. Depression in pregnancy may be associated with decreased antioxidant levels, and this condition may cause an oxidative load, which may lead to improper brain development. Future studies should be performed in larger samples to clarify our preliminary results.

Increased prevalence of anxiety and depression symptoms in patients with coronary artery disease before and after percutaneous coronary intervention treatment

BACKGROUND

Evidence suggests that coronary heart disease (CHD) is associated with increased anxiety and a high incidence of comorbid anxiety and depression. However, the association between percutaneous coronary intervention (PCI) and comorbid anxiety and depression has not been previously investigated. This study aims to determine the relationship between PCI and anxiety and depression symptoms in CHD patients in terms of the occurrence, prone factors, and long-term outcomes of CHD.

METHODS

One hundred seventy CHD patients who underwent PCI treatment between September 2013 and February 2014 at the Second Hospital of Hebei Medical University were randomly selected. All patients independently completed the Hospital Anxiety and Depression Scale (HADS) and a preoperative questionnaire; they also provided details regarding their PCI-related concerns one day before PCI, as well as one day and one, three, six, and 12 months after PCI.

RESULTS

PCI treatment was significantly associated with the symptoms of anxiety, depression, affective disorders, and comorbid anxiety and depression (χ(2) = 90.18, 54.45, 101.59, 64.83; p < 0.01) at each follow-up time point. Moreover, PCI treatment was linearly correlated with each of these psychological issues (p < 0.01).

CONCLUSION

The prevalence of anxiety, depression, and comorbid anxiety and depression symptoms significantly increases one day before and after PCI treatment; however, the incidence of these psychological issues significantly decreases with time following PCI. A low level of education, apprehension with regard to nursing quality, potential cardiac dysfunction, surgery sequelae, and surgery failure are also associated with a high prevalence of anxiety and depression symptoms.

Myeloperoxidase: Bridging the gap in neurodegeneration

Neurodegenerative conditions present a group of complex disease pathologies mostly due to unknown aetiology resulting in neuronal death and permanent neurological disability. Any undesirable stress to the brain, disrupts homeostatic balance, through a remarkable convergence of pathophysiological changes and immune dysregulation. The crosstalk between inflammatory and oxidative mechanisms results in the release of neurotoxic mediators apparently spearheaded by myeloperoxidase derived from activated microglia, astrocytes, neurons as well as peripheral inflammatory cells. These isolated entities combinedly have the potential to flare up and contribute significantly to neuropathology and disease progression. Recent, clinicopathological evidence support the association of myeloperoxidase and its cytotoxic product, hypochlorous acid in a plethora of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Multiple sclerosis, Stroke, Epilepsy etc. But the biochemical and mechanistic insights into myeloperoxidase mediated neuroinflammation and neuronal death is still an uncharted territory. The current review outlines the emerging recognition of myeloperoxidase in neurodegeneration, which may offer novel therapeutic and diagnostic targets for neurodegenerative disorders.

Inflammation Models of Depression in Rodents: Relevance to Psychotropic Drug Discovery

Inflammation and depression are closely inter-related; inflammation induces symptoms of depression and, conversely, depressed mood and stress favor an inflammatory phenotype. The mechanisms that mediate the ability of inflammation to induce symptoms of depression are intensively studied at the preclinical level. This review discusses how it has been possible to build animal models of inflammation-induced depression based on clinical data and to explore critical mechanisms downstream of inflammation. Namely, we focus on the ability of inflammation to increase the activity of the tryptophan-degrading enzyme, indoleamine 2,3 dioxygenase, which leads to the production of kynurenine and downstream neuroactive metabolites. By acting on glutamatergic neurotransmission, these neuroactive metabolites play a key role in the development of depression-like behaviors. An important outcome of the preclinical research on inflammation-induced depression is the identification of potential novel targets for antidepressant treatments, which include targeting the kynurenine system and production of downstream metabolites, altering transport of kynurenine into the brain, and modulating glutamatergic transmission.

X chromosome-wide analysis identifies DNA methylation sites influenced by cigarette smoking

Background

Tobacco smoking is a major cause of chronic disease worldwide. Smoking may induce cellular and molecular changes including epigenetic modification, with both short-term and long-term modification patterns that may contribute to phenotypic expression of diseases. Recent epigenome-wide association studies (EWAS) have identified dozens of smoking-related DNA methylation (DNAm) sites. However, the X chromosomal DNAm sites have been largely overlooked due to a lack of an analytical framework for dealing with the sex-dimorphic distribution. To identify novel smoking-related DNAm sites on the X chromosome, we examined the modality of each X chromosomal DNAm site and conducted a sex-specific association study of cigarette smoking.

Results

We used a discovery sample of 139 middle-age twins, and three replication samples of 78 twins, 464 and 333 unrelated individuals including 47, 17, 22, and 89 current smokers, respectively. After correction for multiple testing, the top smoking-related DNAm sites in BCOR and TSC22D3 were significantly hypermethylated and hypomethylated, respectively, among current smokers. These smoking-associated sites were replicated with meta-analysis p-values of 9.17 × 10⁻¹² and 1.61 × 10⁻⁹. For both sites, the smoking effects on methylation levels were larger in males than that in females.

Conclusions

Our findings highlight the importance of investigating X chromosome methylation patterns and their associations with environmental exposures and disease phenotypes and demonstrate a robust statistical methodology for such study. Existing EWAS of human diseases should incorporate the X chromosomal sites to complete a comprehensive epigenome-wide scan.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0189-2) contains supplementary material, which is available to authorized users.

Psychological and social resources relate to biomarkers of allostasis in newly admitted nursing home residents

OBJECTIVES

This paper presents preliminary baseline data from a prospective study of nursing home adaptation that attempts to capture the complexity of residents' adaptive resources by examining psychological, social, and biological variables from a longitudinal conceptual framework. Our emphasis was on validating an index of allostasis.

METHOD

In a sample of 26 long-term care patients, we measured 6 hormone and protein biomarkers to capture the concept of allostasis as an index of physiological resilience, related to other baseline resources, including frailty, hope and optimism, social support, and mental health history, collected via interview with the resident and collaterals. We also examined the performance of self-report measures reflecting psychosocial and well-being constructs, given the prevalence of cognitive impairment in nursing homes.

RESULTS

Our results supported both the psychometric stability of our self-report measures, and the preliminary validity of our index of allostasis. Each biomarker was associated with at least one other resilience resource, suggesting that our choice of biomarkers was appropriate. As a group, the biomarkers showed good correspondence with the majority of other resource variables, and our standardized summation score was also associated with physical, social, and psychological resilience resources, including those reflecting physical and mental health vulnerability as well as positive resources of social support, optimism, and hope.

CONCLUSION

Although these results are based on a small sample, the effect sizes were large enough to confer some confidence in the value of pursuing further research relating biomarkers of allostasis to psychological and physical resources and well-being.