Bipolar disorder: role of immune-inflammatory cytokines, oxidative and nitrosative stress and tryptophan catabolites

Bipolar disorder staging and the impact it has on its management: an update

INTRODUCTION

The longitudinal course of bipolar disorder (BD) is associated with an active process of neuroprogression, characterized by structural brain alterations and progressive functional impairment. In the last decades, a growing need of a standardized staging model for BD arose, with the aim of a more appropriate definition of stage-specific clinical manifestations and the identification of more customized therapeutic tools.

AREAS COVERED

The authors review the literature on clinical aspects, neurobiological correlates and treatment issues related to BD progression. Thereafter, they address the definition, constructs, and evolution of the staging concept, focusing on the clinical applications of BD staging models available in literature.

EXPERT OPINION

Although several staging models for BD have been proposed to date, their application in clinical practice is still relatively scant. This may have a detrimental impact on the clinical and therapeutic management of BD, in terms of early and proper diagnosis as well as tailored treatment interventions according to the different stages of illness. Future research efforts should tend to the integration of recent insights on neuroimaging and epigenetic markers, toward a standardized and multidimensional staging model.

Higher Seasonal Variation of Systemic Inflammation in Bipolar Disorder

Seasonal rhythms affect the immune system. Evidence supports the involvement of immuno-inflammatory mechanisms in bipolar disorder (BD), with the neutrophil to lymphocyte ratio (NLR), and the systemic immune-inflammatory index (SII; platelets × neutrophils/lymphocytes) consistently reported to be higher in patients with BD than in HC, but seasonal rhythms of innate and adaptive immunity have never been studied. We retrospectively studied NLR and SII in 824 participants divided into three groups: 321 consecutively admitted inpatients affected by a major depressive episode in course of BD, and 255 consecutively admitted inpatients affected by obsessive-compulsive disorder (OCD; positive psychiatric control), and 248 healthy controls (HC). Patients with BD showed markedly higher markers of systemic inflammation in autumn and winter, but not in spring and summer, in respect to both HC and patients with OCD, thus suggesting a specific effect of season on inflammatory markers in BD, independent of a shared hospital setting and drug treatment. Given that systemic inflammation is emerging as a new marker and as target for treatment in depressive disorders, we suggest that seasonal rhythms should be considered for tailoring antidepressant immuno-modulatory treatments in a precision medicine approach.

P2X7 receptor inhibition alleviates mania-like behavior independently of interleukin-1β

Purinergic dysfunctions are associated with mania and depression pathogenesis. P2X7 receptor (P2X7R) mediates the IL-1β maturation via NLRP3 inflammasome activation. We tested in a mouse model of the subchronic amphetamine (AMPH)-induced hyperactivity whether P2X7R inhibition alleviated mania-like behavior through IL-1β. Treatment with JNJ-47965567, a P2X7R antagonist, abolished AMPH-induced hyperlocomotion in wild-type and IL-1α/β-knockout male mice. The NLRP3 inhibitor MCC950 failed to reduce AMPH-induced locomotion in WT mice, whereas the IL-1 receptor antagonist anakinra slightly increased it. AMPH increased IL-10, TNF-α, and TBARS levels, but did not influence BDNF levels, serotonin, dopamine, and noradrenaline content in brain tissues in either genotypes. JNJ-47965567 and P2rx7-gene deficiency, but not IL-1α/β-gene deficiency, attenuated AMPH-induced [3H]dopamine release from striatal slices. In wild-type and IL-1α/β-knockout female mice, JNJ-47965567 was also effective in attenuating AMPH-induced hyperlocomotion. This study suggests that AMPH-induced hyperactivity is modulated by P2X7Rs, but not through IL-1β.

Neutrophil-to-lymphocyte ratio as a predictive biomarker for early diagnosis of depression: A narrative review

Depression is a mood disorder that causes persistent feelings of sadness, hopelessness, loss of interest, and decreased energy. Early diagnosis of depression can improve its negative impacts and be effective in its treatment. Previous studies have indicated that inflammation plays an important role in the initiation and development of depression, hence, various inflammatory biomarkers have been investigated for early diagnosis of depression, the most popular of which are blood biomarkers. The Neutrophil to lymphocyte ratio (NLR) may be more informative in the early diagnosis of depression than other widely used markers, such as other leukocyte characteristics or interleukins. Considering the importance of early diagnosis of depression and the role of NLR in early diagnosis of depression, our paper reviews the literature on NLR as a diagnostic biomarker of depression, which may be effective in its treatment. Various studies have shown that elevated NLR is associated with depression, suggesting that NLR may be a valuable, reproducible, easily accessible, and cost-effective method for the evaluation of depression and it may be used in outpatient clinic settings. Closer follow-up can be performed for these patients who have higher NLR levels. However, it seems that further studies on larger samples, taking into account important confounding factors, and assessing them together with other inflammatory markers are necessary to draw some conclusive statements.

Monoclonal antibody precision therapy targeting inflammation for bipolar disorder: a narrative review

Bipolar disorder (BD) is a severe mental disorder with various hypotheses regarding its pathogenesis. This article provides a summary of numerous studies on the variations in inflammatory cytokine levels in patients with BD and the effects of treatment with antipsychotics, mood stabilizers, and antidepressants on these levels. In addition, patients with autoimmune diseases who use anti-inflammatory monoclonal antibodies experience symptoms, such as depression, anxiety, and insomnia. These pieces of evidence suggest a potential association between immune inflammation and BD and offer new possibilities for therapy. Building upon this relationship, the authors propose an innovative approach for treating BD through individualized and precise therapy using anti-inflammatory monoclonal antibody drugs. To support this proposal, the authors compile information on pharmacological effects and relevant studies, including trials of various anti-inflammatory therapeutic monoclonal antibody drugs (e.g. infliximab, tocilizumab, and canakinumab) for the potential treatment of BD and its associated side effects in psychiatry. The authors categorize these anti-inflammatory monoclonal antibody drugs into levels I-IV through a comprehensive analysis of their advantages and disadvantages. Their potential is examined, and the need for further exploration of their pharmaceutical effects is established.

Dissecting clinical and biological heterogeneity in clinical states of bipolar disorder: a 10-year retrospective study from China

Objectives

To dissect clinical and biological heterogeneity in clinical states of bipolar disorder (BD), and investigate if neuropsychological symptomatology, comorbidity, vital signs, and blood laboratory indicators are predictors of distinct BD states.

Methods

A retrospective BD cohort was established with data extracted from a Chinese hospital's electronic medical records (EMR) between 2009 and 2018. Subjects were inpatients with a main discharge diagnosis of BD and were assessed for clinical state at hospitalization. We categorized all subjects into manic state, depressive state, and mixed state. Four machine learning classifiers were utilized to classify the subjects. A Shapley additive explanations (SHAP) algorithm was applied to the classifiers to aid in quantifying and visualizing the contributions of each feature that drive patient-specific classifications.

Results

A sample of 3,085 records was included (38.54% as manic, 56.69% as depressive, and 4.77% as mixed state). Mixed state showed more severe suicidal ideation and psychomotor abnormalities, while depressive state showed more common anxiety, sleep, and somatic-related symptoms and more comorbid conditions. Higher levels of body temperature, pulse, and systolic and diastolic blood pressures were present during manic episodes. Xgboost achieved the best AUC of 88.54% in manic/depressive states classification; Logistic regression and Random forest achieved the best AUCs of 75.5 and 75% in manic/mixed states and depressive/mixed states classifications, respectively. Myocardial enzymes and the non-enzymatic antioxidant uric acid and bilirubin contributed significantly to distinguish BD clinical states.

Conclusion

The observed novel biological associations with BD clinical states confirm that biological heterogeneity contributes to clinical heterogeneity of BD.

Attention TurkerNeXt: Investigations into Bipolar Disorder Detection Using OCT Images

Background and Aim: In the era of deep learning, numerous models have emerged in the literature and various application domains. Transformer architectures, particularly, have gained popularity in deep learning, with diverse transformer-based computer vision algorithms. Attention convolutional neural networks (CNNs) have been introduced to enhance image classification capabilities. In this context, we propose a novel attention convolutional model with the primary objective of detecting bipolar disorder using optical coherence tomography (OCT) images. Materials and Methods: To facilitate our study, we curated a unique OCT image dataset, initially comprising two distinct cases. For the development of an automated OCT image detection system, we introduce a new attention convolutional neural network named "TurkerNeXt". This proposed Attention TurkerNeXt encompasses four key modules: (i) the patchify stem block, (ii) the Attention TurkerNeXt block, (iii) the patchify downsampling block, and (iv) the output block. In line with the swin transformer, we employed a patchify operation in this study. The design of the attention block, Attention TurkerNeXt, draws inspiration from ConvNeXt, with an added shortcut operation to mitigate the vanishing gradient problem. The overall architecture is influenced by ResNet18. Results: The dataset comprises two distinctive cases: (i) top to bottom and (ii) left to right. Each case contains 987 training and 328 test images. Our newly proposed Attention TurkerNeXt achieved 100% test and validation accuracies for both cases. Conclusions: We curated a novel OCT dataset and introduced a new CNN, named TurkerNeXt in this research. Based on the research findings and classification results, our proposed TurkerNeXt model demonstrated excellent classification performance. This investigation distinctly underscores the potential of OCT images as a biomarker for bipolar disorder.

T cells: an emerging cast of roles in bipolar disorder

Bipolar disorder (BD) is a distinctly heterogeneous and multifactorial disorder with a high individual and social burden. Immune pathway dysregulation is an important pathophysiological feature of BD. Recent studies have suggested a potential role for T lymphocytes in the pathogenesis of BD. Therefore, greater insight into T lymphocytes' functioning in patients with BD is essential. In this narrative review, we describe the presence of an imbalance in the ratio and altered function of T lymphocyte subsets in BD patients, mainly in T helper (Th) 1, Th2, Th17 cells and regulatory T cells, and alterations in hormones, intracellular signaling, and microbiomes may be potential causes. Abnormal T cell presence explains the elevated rates of comorbid inflammatory illnesses in the BD population. We also update the findings on T cell-targeting drugs as potentially immunomodulatory therapeutic agents for BD disease in addition to classical mood stabilizers (lithium, valproic acid). In conclusion, an imbalance in T lymphocyte subpopulation ratios and altered function may be involved in the development of BD, and maintaining T cell immune homeostasis may provide an overall therapeutic benefit.

Gut Microbiome-Brain Alliance: A Landscape View into Mental and Gastrointestinal Health and Disorders

Gut microbiota includes a vast collection of microorganisms residing within the gastrointestinal tract. It is broadly recognized that the gut and brain are in constant bidirectional communication, of which gut microbiota and its metabolic production are a major component, and form the so-called gut microbiome-brain axis. Disturbances of microbiota homeostasis caused by imbalance in their functional composition and metabolic activities, known as dysbiosis, cause dysregulation of these pathways and trigger changes in the blood-brain barrier permeability, thereby causing pathological malfunctions, including neurological and functional gastrointestinal disorders. In turn, the brain can affect the structure and function of gut microbiota through the autonomic nervous system by regulating gut motility, intestinal transit and secretion, and gut permeability. Here, we examine data from the CAS Content Collection, the largest collection of published scientific information, and analyze the publication landscape of recent research. We review the advances in knowledge related to the human gut microbiome, its complexity and functionality, its communication with the central nervous system, and the effect of the gut microbiome-brain axis on mental and gut health. We discuss correlations between gut microbiota composition and various diseases, specifically gastrointestinal and mental disorders. We also explore gut microbiota metabolites with regard to their impact on the brain and gut function and associated diseases. Finally, we assess clinical applications of gut-microbiota-related substances and metabolites with their development pipelines. We hope this review can serve as a useful resource in understanding the current knowledge on this emerging field in an effort to further solving of the remaining challenges and fulfilling its potential.

Comparison of oxidative stress parameters, thiol-disulfide homeostasis, and pro-inflammatory cytokines levels in patients with bipolar disorder and their first-degree relatives

BACKGROUND

In this study, we aimed to compare the oxidative stress parameters, thiol-disulfide homeostasis, and plasma pro-inflammatory cytokines levels of patients with bipolar disorder (BD), BD patients' first-degree relatives (FDRs), and the healthy controls (HCs).

METHODS

Thirty-five patients with BD, 35 FDRs of BD, and 35 healthy controls (HCs) were included. The individuals' ages varied from 28 to 58, and the groups were well-matched in terms of age and gender. The total thiol (TT), native thiol (NT), disulfide (DIS), total oxidant status (TOS), total antioxidant status (TAS), IL-1β, IL-6, and TNF-α concentrations were measured from serum samples. The oxidative stress index (OSI) was calculated using mathematical formulas.

RESULTS

TOS was significantly higher in both patients and FDRs than HCs (p < 0.01 for all pairwise comparisons). OSI, DIS, oxidized thiol, and the ratio of thiol oxidation-reduction levels were significantly higher in both patients with BD and FDRs than HCs (p < 0.01 for all pairwise comparisons). TAS, TT, NT, and reduced thiol levels were significantly lower in both patients with BD and FDRs than HCs (p < 0.01 for all pairwise comparisons). IL-1β, IL-6, and TNF-α were significantly higher in both patients and FDRs than HCs (p < 0.01 for all pairwise comparisons).

LIMITATIONS

Small sample size.

CONCLUSIONS

Early diagnosis is important for treating of bipolar disorder. TT, NT, DIS, TOS, TAS, OSI, IL1-β, IL-6, and TNF-α can be used as potential biomarkers in the early diagnosis and intervention of BD. Furthermore, oxidative/antioxidative markers and plasma pro-inflammatory cytokine parameters may guide the determination of the disease's activity and response to treatment.

Proteome-wide Mendelian randomization reveals the causal effects of immune-related plasma proteins on psychiatric disorders

Immune dysregulation has been consistently reported in psychiatric disorders, however, the causes and mechanisms underlying immune dysregulation in psychiatric disorders remain largely unclear. Here we conduct a Mendelian randomization study by integrating plasma proteome and GWASs of schizophrenia, bipolar disorder and depression. The primate-specific immune-related protein BTN3A3 showed the most significant associations with all three psychiatric disorders. In addition, other immune-related proteins, including AIF1, FOXO3, IRF3, CFHR4, IGLON5, FKBP2, and PI3, also showed significant associations with psychiatric disorders. Our study showed that a proportion of psychiatric risk variants may contribute to disease risk by regulating immune-related plasma proteins, providing direct evidence that connect the genetic risk of psychiatric disorders to immune system.

The Microbiota-Gut-Brain Axis: Psychoneuroimmunological Insights

There is growing interest in the role that the intestinal microbiota and the related autoimmune processes may have in the genesis and presentation of some psychiatric diseases. An alteration in the communication of the microbiota-gut-brain axis, which constitutes a communicative model between the central nervous system (CNS) and the gastro-enteric tract, has been identified as one of the possible causes of some psychiatric diseases. The purpose of this narrative review is to describe evidence supporting a role of the gut microbiota in psychiatric diseases and the impact of diet on microbiota and mental health. Change in the composition of the gut microbiota could determine an increase in the permeability of the intestinal barrier, leading to a cytokine storm. This could trigger a systemic inflammatory activation and immune response: this series of events could have repercussions on the release of some neurotransmitters, altering the activity of the hypothalamic-pituitary-adrenal axis, and reducing the presence of trophic brain factors. Although gut microbiota and psychiatric disorders seem to be connected, more effort is needed to understand the potential causative mechanisms underlying the interactions between these systems.

Neuroprotective Effects of N-acetylserotonin and Its Derivative

N-acetylserotonin (NAS) is a chemical intermediate in melatonin biosynthesis. NAS and its derivative N-(2-(5-hydroxy-1H-indol-3-yl) ethyl)-2-oxopiperidine-3-carboxamide (HIOC) are potential therapeutic agents for traumatic brain injury, autoimmune encephalomyelitis, hypoxic-ischemic encephalopathy, and other diseases. Evidence shows that NAS and its derivative HIOC have neuroprotective properties, and can exert neuroprotective effects by inhibiting oxidative stress, anti-apoptosis, regulating autophagy dysfunction, and anti-inflammatory. In this review, we discussed the neuroprotective effects and related mechanisms of NAS and its derivative HIOC to provide a reference for follow-up research and applications.

Glial-Neuronal Interaction in Synapses: A Possible Mechanism of the Pathophysiology of Bipolar Disorder

Bipolar disorder (BD) is a severe and chronic psychiatric disorder that affects approximately 1-4% of the world population and is characterized by recurrent episodes of mania or hypomania and depression. BD is also associated with illnesses marked by immune activation, such as metabolic syndrome, obesity, type 2 diabetes mellitus, and cardiovascular diseases. Indeed, a connection has been suggested between neuroinflammation and peripheral inflammatory markers in the pathophysiology of BD, which can be associated with the modulation of many dysfunctional processes, including synaptic plasticity, neurotransmission, neurogenesis, neuronal survival, apoptosis, and even cognitive/behavioral functioning. Rising evidence suggests that synaptic dysregulations, especially glutamatergic system dysfunction, are directly involved in mood disorders. It is becoming clear that dysregulations in connection and structural changes of glial cells play a central role in the BD pathophysiology. This book chapter highlighted the latest findings that support the theory of synaptic dysfunction in BD, providing an overview of the alterations in neurotransmitters release, astrocytic uptake, and receptor signaling, as well as the role of inflammation on glial cells in mood disorders. Particular emphasis is given to the alterations in presynaptic and postsynaptic neurons and glial cells, all cellular elements of the "tripartite synapse," compromising the neurotransmitters system, excitatory-inhibitory balance, and neurotrophic states of local networks in mood disorders. Together, these studies provide a foundation of knowledge about the exact role of the glial-neuronal interaction in mood disorders.

Melatonin: Manager of psychosomatic and metabolic disorders in polymorbid cardiovascular pathology

Objectives

To investigate the relationship between changes in circadian patterns of melatonin and clinical manifestations of polymorbid cardiovascular pathology (PCVP) in young men and to analyze the effectiveness of their complex treatment.

Materials and methods

We made the immunohistochemical (IHC) analysis of epiphysis tissues from autopsies of 25 men aged 32–44 with PCVP and metabolic syndrome (MS) who had died as a result of ischemic cardiomyopathy (IC) and 25 persons after the car accident as a control group. Then, 93 young men aged 35–44 with PCVP, metabolic syndrome, and depressive spectrum disorders (DSD) were divided into three groups: (1) standard therapy; (2) standard therapy and psychotherapy sessions; (3) standard therapy in combination with psychotherapeutic and psychophysiological visual and auditory correction sessions. The control group included 24 conditionally healthy male volunteers. Before and after the treatment, we studied the anthropometric status, lipid and carbohydrate metabolism indicators, the level of urinary 6-hydroxymelatonin sulfate, the degree of nocturnal decrease in blood pressure (BP), and the relationship of these indicators with circadian variations of melatonin excretion.

Results

Young polymorbid patients who died from IC have a lower expression of melatonin type 1 and 2 receptors. All patients with PCVP showed a decrease in the nocturnal melatonin excretion fraction and a correlation with higher severity of depressive (r = −0.72) and anxiety (r = −0.66) symptoms. Reduced values of the 6-hydroxymelatonin sulfate (6-SM) in the 1st (r = 0.45), 2nd (r = 0.39), and 3rd (r = 0.51) groups before treatment was associated with periods of increased BP. The achievement of melatonin excretion reference values and normalization of biochemical parameters of carbohydrate and lipid metabolism, daily BP profile, and psychophysiological state were noted in all three patients’ groups, with a more pronounced effect in group 3.

Conclusion

Low nocturnal melatonin excretion levels are associated with greater severity of clinical symptoms and a higher risk of death in patients with PCVP. Therefore, comprehensive therapy may be more effective for correcting this disease.

The Microbiota–Gut–Brain Axis in Psychiatric Disorders

Modulating the gut microbiome and its influence on human health is the subject of intense research. The gut microbiota could be associated not only with gastroenterological diseases but also with psychiatric disorders. The importance of factors such as stress, mode of delivery, the role of probiotics, circadian clock system, diet, and occupational and environmental exposure in the relationship between the gut microbiota and brain function through bidirectional communication, described as “the microbiome–gut–brain axis”, is especially underlined. In this review, we discuss the link between the intestinal microbiome and the brain and host response involving different pathways between the intestinal microbiota and the nervous system (e.g., neurotransmitters, endocrine system, immunological mechanisms, or bacterial metabolites). We review the microbiota alterations and their results in the development of psychiatric disorders, including major depressive disorder (MDD), schizophrenia (SCZ), bipolar disorder (BD), autism spectrum disorder (ASD), and attention-deficit hyperactivity disorder (ADHD).

Tryptophan metabolism: Mechanism-oriented therapy for neurological and psychiatric disorders

Neurological and psychiatric disorders are a category of chronic diseases that are widespread and pose serious mental and physical health problems for patients. The substrates, products, and enzymes of Tryptophan metabolism all contribute to the development of neurological and psychiatric disorders. This paper deals with three metabolic pathways of tryptophan that produce a series of metabolites called tryptophan Catabolics (TRYCATs). These metabolites are involved in pathological processes such as excitotoxicity, neuroinflammation, oxidative stress, and mitochondrial damage and are closely associated with neurological and psychiatric disorders such as Alzheimer’s disease and depression. Here, we review the elements that affect how tryptophan metabolism is regulated, including inflammation and stress, exercise, vitamins, minerals, diet and gut microbes, glucocorticoids, and aging, as well as the downstream regulatory effects of tryptophan metabolism, including the regulation of glutamate (Glu), immunity, G-protein coupled receptor 35 (Gpr35), nicotinic acetylcholine receptor (nAChR), aryl hydrocarbon receptor (AhR), and dopamine (DA). In order to advance the general understanding of tryptophan metabolism in neurological and psychiatric disorders, this paper also summarizes the current situation and effective drugs of tryptophan metabolism in the treatment of neurological and psychiatric disorders and considers its future research prospects.

Severe mental disorders and vaccinations - a systematic review

OBJECTIVES

People with severe mental illnesses (SMI: schizophrenia, depressive disorder, bipolar disorder) have a high risk of being infected by viruses and suffer a more severe infection illness course than the general population. The aim of this literature review was to elucidate rates as well as immunogenicity and side effects of vaccinations in SMI.

METHODS

All studies in the English or German language, which investigated either prevalence rates or effects of vaccinations in the target groups, were systematically searched in the databank PubMed by three independent authors using the PRISMA guidelines and discussed in more detail.

RESULTS

The search found 24 studies reporting epidemiological data and 16 investigating immunogenicity of vaccinations. The results on prevalence rates, antibody production, inflammation response and side effects were inconsistent. About interactions with psychotropic medication, only two studies on clozapine were found.

CONCLUSIONS

Only a few trials with heterogeneous samples have investigated prevalence and effects of vaccinations in SMI. Sex, age and other factors such as somatic comorbidities and special vaccination programmes have not been considered continuously and may influence rates as well. As individuals with SMI might be at special risk, further research on the willingness to be vaccinated as well as efficacy of vaccinations is needed.

The Effect of Adjunctive Probiotics on Markers of Inflammation and Oxidative Stress in Bipolar Disorder: A Double-blind, Randomized, Controlled Trial

BACKGROUND

Bipolar disorder (BD) is a chronic psychiatric illness. Concentrations of inflammatory cytokines are increased in BD. Supplementation with probiotics has shown promising effects in reducing inflammation and producing improvement in clinical symptoms in some psychiatric disorders. Therefore, we designed a clinical trial to assess the effects of adjunctive probiotics on markers of inflammation and oxidative stress in patients with BD.

METHODS

In this 8-week, double-blind, randomized study, 38 patients suffering from BD type I were given a probiotic or placebo capsule each day. Serum levels of interleukin-6 (IL-6), as the primary outcome measure, and of interleukin-10 (IL-10), tumor necrosis factor-α, and malondialdehyde, as the secondary outcome measures, were obtained before and after the intervention.

RESULTS

At the end of the study, the 2 groups showed no significant or clinically meaningful differences in the serum concentrations of IL-6 [Hedge g=0.02, 95% confidence interval (CI): -0.6; 0.64, P=0.936], tumor necrosis factor-α (Hedge g=-0.2, 95% CI: -0.82; 0.42, P=0.554), IL-10 (Hedge g=-0.072, 95% CI: -0.071; 0.56, P=0.827), and malondialdehyde (Hedge g=0.27, 95% CI: -0.37; 0.91, P=0.423).

CONCLUSIONS

This study did not find any significant or conclusive effects of probiotics supplementation on markers of inflammation and oxidative stress in patients with BD. Further studies are needed before a conclusion can be drawn about the efficacy of probiotics in the management of BD.

Willingness to be vaccinated against COVID-19 is equal in individuals with affective disorders and healthy controls

Affective disorders such as major depressive disorder and bipolar disorder are associated with higher infection rates and a more severe course of coronavirus disease (COVID-19). In turn, COVID-19 could trigger mental disease relapse. Vaccinations lead to a reduction of infections and the prevention of severe courses. This work aims to survey the willingness of individuals with affective disorders to get vaccinated and concerns about vaccinations.

METHODS

An online study (April-May 2021) assessed the current infection and vaccination rate amongst individuals with affective disorder in Austria by surveying attitudes towards the vaccination, the willingness to get vaccinated soon and possible reasons for decision. The analyses included 59 individuals with affective disorders and 59 healthy controls, matched for sex and age.

RESULTS

There was an overall high willingness to get vaccinated against COVID-19. Individuals with affective disorders were more skeptical about vaccinations in general but there was no significant difference between the groups in the willingness to get vaccinated against COVID-19. In both groups reasons for waiting were mainly fears of acute and/or long-term side effects and the fast development of the vaccines.

LIMITATIONS

It was a cross sectional design. Due to the online design, no objective rating of current psychopathological symptoms was assessed. Willingness to get vaccinated in general and against COVID-19 in particular were self-created variables, whereas item statistics and factor analysis were conducted.

DISCUSSION

Because of the higher risk for individuals with affective disorders, preventive strategies like vaccinating should be promoted in this group. It is important to help individuals with AD to overcome barriers such as negative beliefs and concerns about acute and/or long-term side effects.

Neutrophil to-lymphocyte and platelet-to-lymphocyte ratios as biomarkers for suicidal behavior in children and adolescents with depression or anxiety treated with selective serotonin reuptake inhibitors

BACKGROUND

Both the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR) have been proposed as biomarkers of suicidal risk in adults with depression. We examined whether these ratios may be considered biomarkers for suicidal behavior in young patients with major depressive or anxiety disorders before treatment with selective serotonin reuptake inhibitors (SSRIs), or as biomarkers for the adverse event of SSRI-associated suicidality.

METHODS

Children and adolescents meeting criteria for major depressive or anxiety disorder were recruited. Serum levels of three pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) were assessed; and NLR and PLR calculated, from blood samples collected at baseline and after 8 weeks treatment with SSRI. A Mann-Whitney test was performed to evaluate differences in NLR and PLR between children with and without a history of a suicide attempt prior to treatment. We compared hematological parameters before and after treatment, and between children who developed SSRI-associated suicidality versus children without treatment emergent suicidality.

RESULTS

Among 91 children and adolescents (aged 13.9 ± 2.4 years), baseline NLR and PLR were significantly higher among those with a history of a suicide attempt versus those without such history. Statistically significant correlations were found for the suicide ideation subscale in the Columbia suicide severity rating scale with both baseline NLR and PLR. Baseline NLR and PLR were similar in children who did and did not develop SSRI-associated suicidality after 8 weeks. In the final logistic regression model (χ2 = 18.504, df = 4, p value = 0.001), after controlling for sex, depression severity and IL-6 levels, NLR was significantly associated with a past suicide attempt (β = 1.247, p = 0.019; OR [95% CI] = 3.478 [1.230-9.841]), with a NLR cut-off value of = 1.76 (area under the curve = 0.75 (95% CI = 0.63-0.88, sensitivity = 73%, and specificity = 71%, p value = 0.003).

CONCLUSIONS

High NLR and PLR values may be associated with suicidal behavior in depressed and anxious children and adolescents. NLR appears as a better predictor of suicide attempt than PLR, and thus may be a useful biomarker of suicidality in young patients with depression or anxiety.

COVID-19 and first manic episodes: a systematic review

Sars-CoV-2 is a respiratory virus that can access the central nervous system, as indicated by the presence of the virus in patients' cerebrospinal fluid and the occurrence of several neurological syndromes during and after COVID-19. Growing evidence indicates that Sars-CoV-2 can also trigger the acute onset of mood disorders or psychotic symptoms. COVID-19-related first episodes of mania, in subjects with no known history of bipolar disorder, have never been systematically analyzed. Thus, the present study assesses a potential link between the two conditions. This systematic review analyzes cases of first appearance of manic episodes associated with COVID-19. Clinical features, pharmacological therapies, and relationships with pre-existing medical conditions are also appraised. Medical records of twenty-three patients fulfilling the current DSM-5 criteria for manic episode were included. Manic episodes started, on average, after 12.71±6.65 days from the infection onset. Psychotic symptoms were frequently reported. 82.61% of patients exhibited delusions, whereas 39.13% of patients presented hallucinations. A large discrepancy in the diagnostic workups was observed. Mania represents an underestimated clinical presentation of COVID-19. Further studies should focus on the pathophysiological substrates of COVID-19-related mania and pursue appropriate and specific diagnostic and therapeutic workups.

Curcumin for attention-deficit-hyperactivity disorder: a systematic review and preliminary behavioral investigation

Curcumin has protective actions in neuropsychiatric disorders, acting as a neuroprotective agent. As a first approach, the study aimed at a systematic review of the potential effects of curcumin on cognitive performance for attention-deficit-hyperactivity disorder (ADHD). This research was carried out in the databases of PubMed, Embase, SciELO, the Cochrane Central Register of Controlled Trials (CENTRAL), the Web of Science, and the Grey literature. Upon discovering the scarcity of relevant studies, and knowing that curcumin might have an ADHD hyperactive and anxious behavior, the study proposed to evaluate the effects of curcumin in an ADHD phenotype of spontaneously hypertensive Wistar rats (SHR). No studies were found that related to curcumin and ADHD. Fifteen SHRs were then divided into separate groups that received water (1 mg/kg/day), curcumin (50 mg/kg/day), or methylphenidate (1 mg/kg/day) for 42 days. Behavioral tests to assess activity (Open Field Test), anxiety and impulsivity (Elevated Plus-Maze, and Social Interaction), and memory (Y-Maze, and the Object Recognition Test) were all performed. The animals that were treated with curcumin showed less anxious and hyperactive behavior, as seen in the Open Field Test and the Social Interaction Test. Anxious behavior was measured by the EPM and was not modulated by any treatment. The results of the Y-Maze Test demonstrated that curcumin improved spatial memory. In the Object Recognition Test, neither the short nor the long-term memory was improved. The treatments that were used in this study beneficially modulated the anxious and hyperactive behavior of the SHR.

Association between neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and C-reactive protein levels and metabolic status in patients with a bipolar disorder

OBJECTIVES

Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and C-Reactive Protein (CRP) are markers of inflammation that are elevated in bipolar disorder (BD) and are also related to a higher risk of metabolic syndrome (MetS). This study aimed at investigating for the first time the association between NLR, PLR, and CRP and the metabolic status in BD.

METHODS

We assessed the association between biomarkers and the metabolic status: number of metabolic risk factors, presence of MetS, insulin sensitivity (Quantitative Insulin Sensitivity Check Index, QUICKI) and insulin resistance (Homeostatic Model Assessment for Insulin Resistance, HOMA-IR index), in a sample of 219 outpatients with BD.

RESULTS

25.9% of the sample met the criteria for MetS. High levels of CRP were found in 12% of the sample. Older age, low PLR, high NLR, and high CRP levels significantly predicted a higher number of MetS risk factors (p < 0.001). Older age and low PLR were associated with a greater likelihood of developing MetS (p = 0.007).

CONCLUSIONS

Although further studies are needed to replicate and validate these findings, inflammatory biomarkers as CRP, PLR and NLR could be useful tools to identify patients with a BD at risk for a metabolic adverse outcome.

Comparative study of brain damage and oxidative stress using two animal models of the shaken baby syndrome

The objective was compare the morphological damages in brain and to evaluate the participation of oxidative stress, using two animal models of shaken baby syndrome (SBS). Five-day-old Wistar rats were used to develop two models of SBS as follows: Gyrotwister (GT) group was subjected to low intensity, high duration rotating movements and Ratshaker (RS) group made to undergo high intensity, low duration anteroposterior movements. Both groups presented respiratory distress, weight loss and shorter stature compared with the control group. In addition, involuntary movements occurred in both experimental models. Hemorrhage was observed in 10 % of the GT group and in 40 % of the RS group. This last group experienced lesser weight gain at 30 days. Glutathione decreased by 25.7 % (GT) and 59.96 (RT). Cell data analysis revealed the presence of crenate and pyknotic cells, characterized by apparent absence of nucleus and nucleolus as well as vacuolation in the GT group. In the RS group, there were a high number of angular, pyknotic and shrunken cells, and a lot of vacuolization. The severity of the brain damage can be related to the magnitude of biochemical modifications, specifically, those related to the production of reactive oxygen or nitrogen species, oxidative stress, oxidative damage.

The role of base excision repair in major depressive disorder and bipolar disorder

BACKGROUND

In vivo and in vitro studies suggest that inflammation and oxidative damage may contribute to the pathogenesis of major depressive disorder (MDD) and bipolar disorder (BD). Imbalance between DNA damage and repair is an emerging research area examining pathophysiological mechanisms of these major mood disorders. This systematic review sought to review DNA repair enzymes, with emphasis on the base excision repair (BER), in mood disorders.

METHODS

We conducted a comprehensive literature search of Ovid MEDLINE® Epub Ahead of Print, Ovid MEDLINE® In-Process & Other Non-Indexed Citations, Ovid MEDLINE® Daily, EMBASE (1947), and PsycINFO for studies investigating the alterations in base excision repair in patients with MDD or BD.

RESULTS

A total of 1364 records were identified. 1352 records remained after duplicates were removed. 24 records were selected for full-text screening and a remaining 12 articles were included in the qualitative synthesis. SNPs (single nucleotide polymorphisms) of several BER genes have been shown to be associated with MDD and BD. However, it was difficult to draw conclusions from BER gene expression studies due to conflicting findings and the small number of studies.

LIMITATIONS

All studies were correlational so it was not possible to draw conclusions regarding causality.

CONCLUSION

Future studies comparing DNA repair during the manic or depressive episode to remission will give us a better insight regarding the role of DNA repair in mood disorders. These alterations might be utilized as diagnostic and prognostic biomarkers as well as measuring treatment response.

Is Poor Lithium Response in Individuals with Bipolar Disorder Associated with Increased Degradation of Tryptophan along the Kynurenine Pathway? Results of an Exploratory Study

Bipolar disorder is associated with an inflammation-triggered elevated catabolism of tryptophan to the kynurenine pathway, which impacts psychiatric symptoms and outcomes. The data indicate that lithium exerts anti-inflammatory effects by inhibiting indoleamine-2,3-dioxygenase (IDO)-1 activity. This exploratory study aimed to investigate the tryptophan catabolism in individuals with bipolar disorder (n = 48) compared to healthy controls (n = 48), and the associations with the response to mood stabilizers such as lithium, valproate, or lamotrigine rated with the Retrospective Assessment of the Lithium Response Phenotype Scale (or the Alda scale). The results demonstrate an association of a poorer response to lithium with higher levels of kynurenine, kynurenine/tryptophan ratio as a proxy for IDO-1 activity, as well as quinolinic acid, which, overall, indicates a pro-inflammatory state with a higher degradation of tryptophan towards the neurotoxic branch. The treatment response to valproate and lamotrigine was not associated with the levels of the tryptophan metabolites. These findings support the anti-inflammatory properties of lithium. Furthermore, since quinolinic acid has neurotoxic features via the glutamatergic pathway, they also strengthen the assumption that the clinical drug response might be associated with biochemical processes. The relationship between the lithium response and the measurements of the tryptophan to the kynurenine pathway is of clinical relevance and may potentially bring advantages towards a personalized medicine approach to bipolar disorder that allows for the selection of the most effective mood-stabilizing drug.

The Immune Profile of Major Dysmood Disorder: Proof of Concept and Mechanism Using the Precision Nomothetic Psychiatry Approach

Major depressive disorder and a major depressive episode (MDD/MDE) are characterized by activation of the immune-inflammatory response system (IRS) and the compensatory immune-regulatory system (CIRS). In MDD/MDE, recent precision nomothetic psychiatry studies discovered a new endophenotype class, namely major dysmood disorder (MDMD), a new pathway phenotype, namely reoccurrence of illness (ROI), and a new model of the phenome of depression. The aim of the present study is to examine the association between ROI, the phenome of depression, and MDMD’s features and IRS, CIRS, macrophages (M1), T helper (Th)1, Th2, Th17, T regulatory, and growth factor (GF) profiles. Culture supernatants of unstimulated and stimulated (5 μg/mL of PHA and 25 μg/mL of LPS) diluted whole blood of 30 MDD/MDE patients and 20 controls were assayed for cytokines/GF using the LUMINEX assay. MDMD was characterized by increased M1, Th1, Th2, Th17, Treg, IRS, CIRS, neurotoxicity, and GF profiles. Factor analysis shows that ROI features and immune-GF profiles may be combined into a new pathway phenotype (an extracted latent vector). ROI, lifetime and recent suicidal behaviors, and severity of depression are significantly associated with immunotoxicity and GF profiles. Around 80.0% of the variance in the phenome is predicted by ROI and neurotoxicity or the IRS/CIRS ratio. The molecular pathways underpinning ROI-associated sensitization of immune/growth networks are transmembrane receptor protein kinase-triggered STAT protein phosphorylation, TLR/NF-κB, JAK-STAT, and the main proliferation/survival PI3K/Akt/RAS/MAPK pathway. In conclusion, MDMD’s heightened immune responses are the consequence of ROI-associated sensitization combined with immunostimulatory triggers.

Malondialdehyde as a candidate biomarker for bipolar disorder: A meta-analysis

Malondialdehyde (MDA) represents one of the final products of lipid peroxidation that is thought to be enhanced and accelerated in patients affected by bipolar disorder (BD). Purpose of the present article is to critically summarize the available data about MDA as a candidate biomarker for BD. First, we carried out a systematic review of the literature selecting those papers that evaluated MDA levels in BD. Then, we performed two separate meta-analyses: one of the studies that compared healthy controls (HC) with unmedicated BD and one with the studies that assessed MDA levels before and after treatment in BD, showing that bipolar patients experience more oxidative stress than healthy subjects and that treatment is effective in reducing MDA levels. In the first set of studies, we also explored through a meta-regression whether age, gender and experiencing an episode specifically influenced the difference between BD and HC in MDA levels. Bipolar patients compared to healthy subjects had higher MDA levels (SMD: 0.94, 95% CI: 0.23-1.64). Age (p < 0.01), gender (p < 0.01) and the presence of a current mood episode (p < 0.01) significantly influenced MDA plasma/serum levels. Specifically, studies that included more female, older subjects and more BD in euthymia were more likely to have higher MDA levels. Finally, patients after treatment had lower levels of MDA compared to baseline (SMD: -0.52, 95% CI: -0.85 -0.19). More studies are needed to draw definitive conclusions.

Therapeutic Interventions to Mitigate Mitochondrial Dysfunction and Oxidative Stress–Induced Damage in Patients with Bipolar Disorder

Bipolar disorder (BD) is characterized by mood changes, including recurrent manic, hypomanic, and depressive episodes, which may involve mixed symptoms. Despite the progress in neurobiological research, the pathophysiology of BD has not been extensively described to date. Progress in the understanding of the neurobiology driving BD could help facilitate the discovery of therapeutic targets and biomarkers for its early detection. Oxidative stress (OS), which damages biomolecules and causes mitochondrial and dopamine system dysfunctions, is a persistent finding in patients with BD. Inflammation and immune dysfunction might also play a role in BD pathophysiology. Specific nutrient supplements (nutraceuticals) may target neurobiological pathways suggested to be perturbed in BD, such as inflammation, mitochondrial dysfunction, and OS. Consequently, nutraceuticals may be used in the adjunctive treatment of BD. This paper summarizes the possible roles of OS, mitochondrial dysfunction, and immune system dysregulation in the onset of BD. It then discusses OS-mitigating strategies that may serve as therapeutic interventions for BD. It also analyzes the relationship between diet and BD as well as the use of nutritional interventions in the treatment of BD. In addition, it addresses the use of lithium therapy; novel antipsychotic agents, including clozapine, olanzapine, risperidone, cariprazine, and quetiapine; and anti-inflammatory agents to treat BD. Furthermore, it reviews the efficacy of the most used therapies for BD, such as cognitive–behavioral therapy, bright light therapy, imagery-focused cognitive therapy, and electroconvulsive therapy. A better understanding of the roles of OS, mitochondrial dysfunction, and inflammation in the pathogenesis of bipolar disorder, along with a stronger elucidation of the therapeutic functions of antioxidants, antipsychotics, anti-inflammatory agents, lithium therapy, and light therapies, may lead to improved strategies for the treatment and prevention of bipolar disorder.

A unified model of the pathophysiology of bipolar disorder

This work provides an overview of the most consistent alterations in bipolar disorder (BD), attempting to unify them in an internally coherent working model of the pathophysiology of BD. Data on immune-inflammatory changes, structural brain abnormalities (in gray and white matter), and functional brain alterations (from neurotransmitter signaling to intrinsic brain activity) in BD were reviewed. Based on the reported data, (1) we hypothesized that the core pathological alteration in BD is a damage of the limbic network that results in alterations of neurotransmitter signaling. Although heterogeneous conditions can lead to such damage, we supposed that the main pathophysiological mechanism is traceable to an immune/inflammatory-mediated alteration of white matter involving the limbic network connections, which destabilizes the neurotransmitter signaling, such as dopamine and serotonin signaling. Then, (2) we suggested that changes in such neurotransmitter signaling (potentially triggered by heterogeneous stressors onto a structurally-damaged limbic network) lead to phasic (and often recurrent) reconfigurations of intrinsic brain activity, from abnormal subcortical-cortical coupling to changes in network activity. We suggested that the resulting dysbalance between networks, such as sensorimotor networks, salience network, and default-mode network, clinically manifest in combined alterations of psychomotricity, affectivity, and thought during the manic and depressive phases of BD. Finally, (3) we supposed that an additional contribution of gray matter alterations and related cognitive deterioration characterize a clinical-biological subgroup of BD. This model may provide a general framework for integrating the current data on BD and suggests novel specific hypotheses, prompting for a better understanding of the pathophysiology of BD.

Intersections between Copper, β-Arrestin-1, Calcium, FBXW7, CD17, Insulin Resistance and Atherogenicity Mediate Depression and Anxiety Due to Type 2 Diabetes Mellitus: A Nomothetic Network Approach

Type 2 diabetes mellitus (T2DM) is frequently accompanied by affective disorders with a prevalence of comorbid depression of around 25%. Nevertheless, the biomarkers of affective symptoms including depression and anxiety due to T2DM are not well established. The present study delineated the effects of serum levels of copper, zinc, β-arrestin-1, FBXW7, lactosylceramide (LacCer), serotonin, calcium, magnesium on severity of depression and anxiety in 58 men with T2DM and 30 healthy male controls beyond the effects of insulin resistance (IR) and atherogenicity. Severity of affective symptoms was assessed using the Hamilton Depression and Anxiety rating scales. We found that 61.7% of the variance in affective symptoms was explained by the multivariate regression on copper, β-arrestin-1, calcium, and IR coupled with atherogenicity. Copper and LacCer (positive) and calcium and BXW7 (inverse) had significant specific indirect effects on affective symptoms, which were mediated by IR and atherogenicity. Copper, β-arrestin-1, and calcium were associated with affective symptoms above and beyond the effects of IR and atherogenicity. T2DM and affective symptoms share common pathways, namely increased atherogenicity, IR, copper, and β-arrestin-1, and lowered calcium, whereas copper, β-arrestin-1, calcium, LacCer, and FBXW7 may modulate depression and anxiety symptoms by affecting T2DM.

Development and validation of a nomogram based on lymphocyte subsets to distinguish bipolar depression from major depressive disorder

OBJECTIVE

Bipolar depression (BD) and major depressive disorder (MDD) are both common affective disorders. The common depression episodes make it difficult to distinguish between them, even for experienced clinicians. Failure to properly diagnose them in a timely manner leads to inappropriate treatment strategies. Therefore, it is important to distinguish between BD and MDD. The aim of this study was to develop and validate a nomogram model that distinguishes BD from MDD based on the characteristics of lymphocyte subsets.

MATERIALS AND METHODS

A prospective cross-sectional study was performed. Blood samples were obtained from participants who met the inclusion criteria. The least absolute shrinkage and selection operator (LASSO) regression model was used for factor selection. A differential diagnosis nomogram for BD and MDD was developed using multivariable logistic regression and the area under the curve (AUC) with 95% confidence interval (CI) was calculated, as well as the internal validation using a bootstrap algorithm with 1,000 repetitions. Calibration curve and decision curve analysis (DCA) were used to evaluate the calibration and clinical utility of the nomogram, respectively.

RESULTS

A total of 166 participants who were diagnosed with BD (83 cases) or MDD (83 cases), as well as 101 healthy controls (HCs) between June 2018 and January 2022 were enrolled in this study. CD19⁺ B cells, CD3⁺ T cells, CD3^-CD16/56⁺ NK cells, and total lymphocyte counts were strong predictors of the diagnosis of BD and MDD and were included in the differential diagnosis nomogram. The AUC of the nomogram and internal validation were 0.922 (95%; CI, 0.879-0.965), and 0.911 (95% CI, 0.838-0.844), respectively. The calibration curve used to discriminate BD from MDD showed optimal agreement between the nomogram and the actual diagnosis. The results of DCA showed that the net clinical benefit was significant.

CONCLUSION

This is an easy-to-use, repeatable, and economical nomogram for differential diagnosis that can help clinicians in the individual diagnosis of BD and MDD patients, reduce the risk of misdiagnosis, facilitate the formulation of appropriate treatment strategies and intervention plans.

Tryptophan Metabolism in Bipolar Disorder in a Longitudinal Setting

Immune-mediated inflammatory processes and oxidative stress are involved in the aetiopathogenesis of bipolar disorder (BD) and weight-associated comorbidities. Tryptophan breakdown via indoleamine 2,3-dioxygenase-1 (IDO-1) along the kynurenine axis concomitant with a pro-inflammatory state was found to be more active in BD, and associated with overweight/obesity. This study aimed to investigate tryptophan metabolism in BD compared to controls (C), stratified by weight classes, in a longitudinal setting, dependent on the incidence of BD episodes. Peripheral tryptophan, kynurenine, and neopterin were assessed in the serum of 226 BD individuals and 142 C. Three samples in a longitudinal assessment were used for 75 BD individuals. Results showed a higher kynurenine/tryptophan in both BD compared to C and overweight compared to normal weight persons. Levels remained stable over time. In the longitudinal course, no differences were found between individuals who were constantly euthymic or not, or who had an illness episode or had none. Findings indicate that tryptophan, kynurenine, and IDO-1 activity may play a role in pathophysiology in BD but are not necessarily associated with clinical manifestations. Accelerated tryptophan breakdown along the kynurenine axis may be facilitated by being overweight. This may increase the risk of accumulation of neurotoxic metabolites, impacting BD symptomatology, cognition, and somatic comorbidities.

Metabolic Syndrome Impairs Executive Function in Bipolar Disorder

Background: Metabolic syndrome (MetS) is more prevalent in individuals with bipolar disorder and has a negative impact on cognition, in particular on executive function, which is already impaired in individuals with bipolar disorder compared to healthy controls.

Methods: In a cross-sectional study, we compared 148 euthymic patients with bipolar disorder and 117 healthy controls in cognitive function depending on the diagnosis of MetS. A neuropsychological test battery was used including the Trail Making Test A/B, Stroop Color and Word Interference Test, the d2 Test of Attention Revised, and the California Verbal Learning Test. In addition, MetS variables as well as the defining variables waist circumference, serum triglyceride levels, high-density lipoprotein cholesterol levels, blood pressure, fasting glucose levels, and body mass index were compared between patients and controls. In addition, illness-related variables were associated with MetS in individuals with bipolar disorder.

Results: The prevalence of MetS in patients with bipolar disorder was higher than in controls (30.4 vs. 15.4%). Patients with bipolar disorder with MetS had impaired executive function compared to patients without MetS or healthy controls with and without MetS (p = 0.020). No MetS effects or interaction MetS × Group was found in attention/processing speed (p = 0.883) and verbal learning/memory (p = 0.373). Clinical variables (illness duration, suicidality, number of affective episodes, medication, age of onset, and history of psychosis) did not relate to MetS in bipolar disorder (p > 0.05).

Conclusion: Bipolar disorder comorbid with MetS bears additional risk for impaired executive function. Executive function includes action planning, inhibition, and impulse control and could play a critical role in keeping long-term goals in mind associated with gaining and maintaining a healthy weight.

Polyphenols as adjunctive treatments in psychiatric and neurodegenerative disorders: Efficacy, mechanisms of action, and factors influencing inter-individual response

The pathophysiology of psychiatric and neurodegenerative disorders is complex and multifactorial. Polyphenols possess a range of potentially beneficial mechanisms of action that relate to the implicated pathways in psychiatric and neurodegenerative disorders. The aim of this review is to highlight the emerging clinical trial and preclinical efficacy data regarding the role of polyphenols in mental and brain health, elucidate novel mechanisms of action including the gut microbiome and gene expression, and discuss the factors that may be responsible for the mixed clinical results; namely, the role of interindividual differences in treatment response and the potentially pro-oxidant effects of some polyphenols. Further clarification as part of larger, well conducted randomized controlled trials that incorporate precision medicine methods are required to inform clinical efficacy and optimal dosing regimens.

The kynurenine pathway and bipolar disorder: intersection of the monoaminergic and glutamatergic systems and immune response

Dysfunction in a wide array of systems-including the immune, monoaminergic, and glutamatergic systems-is implicated in the pathophysiology of depression. One potential intersection point for these three systems is the kynurenine (KYN) pathway. This study explored the impact of the prototypic glutamatergic modulator ketamine on the endogenous KYN pathway in individuals with bipolar depression (BD), as well as the relationship between response to ketamine and depression-related behavioral and peripheral inflammatory markers. Thirty-nine participants with treatment-resistant BD (23 F, ages 18-65) received a single ketamine infusion (0.5 mg/kg) over 40 min. KYN pathway analytes-including plasma concentrations of indoleamine 2,3-dioxygenase (IDO), KYN, kynurenic acid (KynA), and quinolinic acid (QA)-were assessed at baseline (pre-infusion), 230 min, day 1, and day 3 post-ketamine. General linear models with restricted maximum likelihood estimation and robust sandwich variance estimators were implemented. A repeated effect of time was used to model the covariance of the residuals with an unstructured matrix. After controlling for age, sex, and body mass index (BMI), post-ketamine IDO levels were significantly lower than baseline at all three time points. Conversely, ketamine treatment significantly increased KYN and KynA levels at days 1 and 3 versus baseline. No change in QA levels was observed post-ketamine. A lower post-ketamine ratio of QA/KYN was observed at day 1. In addition, baseline levels of proinflammatory cytokines and behavioral measures predicted KYN pathway changes post ketamine. The results suggest that, in addition to having rapid and sustained antidepressant effects in BD participants, ketamine also impacts key components of the KYN pathway.

Changes in the gut microbiome associated with infliximab in patients with bipolar disorder

OBJECTIVES

Available information exists supporting the gut-brain axis, but additional information is needed to explore how the gut microbiome changes when exposed to mood disorder treatments. We sought to explore the effects of a novel treatment for bipolar disorder (BD), infliximab, on the gut microbiome.

METHODS

Participants with a primary diagnosis of BD (n = 15) who participated in a 12-week, randomized placebo-controlled trial evaluating the efficacy of adjunctive infliximab in the treatment of BD were recruited and followed. Stool samples were collected prior to randomization and at 12 weeks. 16S rRNA sequencing was employed in order to analyze the gut microbial community profile.

RESULTS

A total of 17 participants were randomized to infliximab (n = 9; mean [SD] age, 47.6 [10.3] years; 8 female) or to placebo (n = 8; mean [SD] age, 45.9 [10.7] years; 7 female) but two participants from the infliximab group were lost to follow-up post randomization. Across all time points, there were no differences in the diversity on either Shannon or Simpson's Diversity indices. Comparison of Aitchison distances revealed a lack of clustering of the microbiota by time point, but did reveal a small overall effect of treatment that was not significantly different at individual time points. There were also no effects of either time or treatment on differential abundance at either the amplicon sequence variant or genus level.

CONCLUSIONS

These observations indicate that no community-wide changes in the microbiota diversity and profile were detected after the use of infliximab treatment.

Melatonin's neuroprotective role in mitochondria and its potential as a biomarker in aging, cognition and psychiatric disorders

Melatonin is an ancient molecule that is evident in high concentrations in various tissues throughout the body. It can be separated into two pools; one of which is synthesized by the pineal and can be found in blood, and the second by various tissues and is present in these tissues. Pineal melatonin levels display a circadian rhythm while tissue melatonin does not. For decades now, melatonin has been implicated in promoting and maintaining sleep. More recently, evidence indicates that it also plays an important role in neuroprotection. The beginning of our review will summarize this literature. As an amphiphilic, pleiotropic indoleamine, melatonin has both direct actions and receptor-mediated effects. For example, melatonin has established effects as an antioxidant and free radical scavenger both in vitro and in animal models. This is also evident in melatonin's prominent role in mitochondria, which is reviewed in the next section. Melatonin is synthesized in, taken up by, and concentrated in mitochondria, the powerhouse of the cell. Mitochondria are also the major source of reactive oxygen species as a byproduct of mitochondrial oxidative metabolism. The final section of our review summarizes melatonin's potential role in aging and psychiatric disorders. Pineal and tissue melatonin levels both decline with age. Pineal melatonin declines in individuals suffering from psychiatric disorders. Melatonin's ability to act as a neuroprotectant opens new avenues of exploration for the molecule as it may be a potential treatment for cases with neurodegenerative disease.

Towards a new model and classification of mood disorders based on risk resilience, neuro-affective toxicity, staging, and phenome features using the nomothetic network psychiatry approach

Current diagnoses of mood disorders are not cross validated. The aim of the current paper is to explain how machine learning techniques can be used to a) construct a model which ensembles risk/resilience (R/R), adverse outcome pathways (AOPs), staging, and the phenome of mood disorders, and b) disclose new classes based on these feature sets. This study was conducted using data of 67 healthy controls and 105 mood disordered patients. The R/R ratio, assessed as a combination of the paraoxonase 1 (PON1) gene, PON1 enzymatic activity, and early life time trauma (ELT), predicted the high-density lipoprotein cholesterol - paraoxonase 1 complex (HDL-PON1), reactive oxygen and nitrogen species (RONS), nitro-oxidative stress toxicity (NOSTOX), staging (number of depression and hypomanic episodes and suicidal attempts), and phenome (the Hamilton Depression and Anxiety scores and the Clinical Global Impression; current suicidal ideation; quality of life and disability measurements) scores. Partial Least Squares pathway analysis showed that 44.2% of the variance in the phenome was explained by ELT, RONS/NOSTOX, and staging scores. Cluster analysis conducted on all those feature sets discovered two distinct patient clusters, namely 69.5% of the patients were allocated to a class with high R/R, RONS/NOSTOX, staging, and phenome scores, and 30.5% to a class with increased staging and phenome scores. This classification cut across the bipolar (BP1/BP2) and major depression disorder classification and was more distinctive than the latter classifications. We constructed a nomothetic network model which reunited all features of mood disorders into a mechanistically transdiagnostic model.

Oxidative stress parameters and antioxidants in patients with bipolar disorder: Results from a meta-analysis comparing patients, including stratification by polarity and euthymic status, with healthy controls

OBJECTIVE

To investigate oxidative stress markers and antioxidants in bipolar disorder (BD).

METHODS

Electronic MEDLINE/PubMed/Cochrane-Library/Scopus/TripDatabase search until 06/30/2019 for studies comparing antioxidant or oxidative stress markers between BD and healthy controls (HCs). Standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated for ≥3 studies.

RESULTS

Forty-four studies (n = 3,767: BD = 1,979; HCs = 1,788) reported on oxidative stress markers malondialdehyde (MDA), thiobarbituric acid reactive substances (TBARS), and total nitrites; antioxidants glutathione (GSH), uric acid, and zinc; or antioxidantenhancing enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and GSH-transferase (GST). Compared with HCs, BD was associated with higher GST (P = .01), CAT (P = .02), nitrites (P < .0001), TBARS (P < .0001), MDA (P = .01), uric acid (P < .0001), and lower GSH (P = .006), without differences in SOD, GPX, and zinc. Compared to HCs, levels were higher in BD-mania for TBARS (P < .0001) and uric acid (P < .0001); in BD-depression for TBARS (P = .02); and BD-euthymia for uric acid (P = .03). Uric acid levels were higher in BD-mania vs BD-depression (P = .002), but not vs BD euthymia. TBARS did not differ between BD-mania and BD-depression. Medication-free BD-mania patients had higher SOD (P = .02) and lower GPX (P < .0001) than HCs. After treatment, BD did not differ from HCs regarding SOD and GPX.

CONCLUSIONS

Beyond a single biomarker of oxidative stress, the combination of several parameters appears to be more informative for BD in general and taking into account illness polarity. BD is associated with an imbalance in oxidative stress with some phase-specificity for uric acid and TBARS and possible treatment benefits for SOD and GPX. Future studies should take into account confounding factors that can modify oxidative stress status and simultaneously measure oxidative stress markers and antioxidants including different blood sources.

Increasing Nrf2 Activity as a Treatment Approach in Neuropsychiatry

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor encoded by NFE2L2. Under oxidative stress, Nrf2 does not undergo its normal cytoplasmic degradation but instead travels to the nucleus, where it binds to a DNA promoter and initiates transcription of anti-oxidative genes. Nrf2 upregulation is associated with increased cellular levels of glutathione disulfide, glutathione peroxidase, glutathione transferases, thioredoxin and thioredoxin reductase. Given its key role in governing the cellular antioxidant response, upregulation of Nrf2 has been suggested as a common therapeutic target in neuropsychiatric illnesses such as major depressive disorder, bipolar disorder and schizophrenia, which are associated with chronic oxidative and nitrosative stress, characterised by elevated levels of reactive oxygen species, nitric oxide and peroxynitrite. These processes lead to extensive lipid peroxidation, protein oxidation and carbonylation, and oxidative damage to nuclear and mitochondrial DNA. Intake of N-acetylcysteine, coenzyme Q₁₀ and melatonin is accompanied by increased Nrf2 activity. N-acetylcysteine intake is associated with improved cerebral mitochondrial function, decreased central oxidative and nitrosative stress, reduced neuroinflammation, alleviation of endoplasmic reticular stress and suppression of the unfolded protein response. Coenzyme Q₁₀, which acts as a superoxide scavenger in neuroglial mitochondria, instigates mitohormesis, ameliorates lipid peroxidation in the inner mitochondrial membrane, activates uncoupling proteins, promotes mitochondrial biogenesis and has positive effects on the plasma membrane redox system. Melatonin, which scavenges mitochondrial free radicals, inhibits mitochondrial nitric oxide synthase, restores mitochondrial calcium homeostasis, deacetylates and activates mitochondrial SIRT3, ameliorates increased permeability of the blood-brain barrier and intestine and counters neuroinflammation and glutamate excitotoxicity.

Neutrophil-to-Lymphocyte, Platelet-to-Lymphocyte and Monocyte-to-Lymphocyte Ratio in Bipolar Disorder

Background: Several inflammatory hypotheses have been suggested to explain the etiopathogenesis of bipolar disorder (BD) and its different phases. Neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), and monocyte-to-lymphocyte (MLR) ratios have been proposed as potential peripheral biomarkers of mood episodes. Methods: We recruited 294 patients affected by BD, of which 143 were experiencing a (hypo)manic episode and 151 were in a depressive phase. A blood sample was drawn to perform a complete blood count. NLR, PLR, and MLR were subsequently calculated. A t-test was performed to evaluate differences in blood cell counts between depressed and (hypo)manic patients and a regression model was then computed. Results: Mean values of neutrophils, platelets, mean platelet volume, NLR, PLR, and MLR were significantly higher in (hypo)manic than depressed individuals. Logistic regression showed that PLR may represent an independent predictor of (hypo)mania. Conclusions: Altered inflammatory indexes, particularly PLR, may explain the onset and recurrence of (hypo)manic episodes in patients with BD. As inflammatory ratios represent economical and accessible markers of inflammation, further studies should be implemented to better elucidate their role as peripheral biomarkers of BD mood episodes.

Involvement of Kynurenine Metabolism in Bipolar Disorder: An Updated Review

Bipolar disorder (BD) is a severe affective disorder, mainly characterized by alternative depressive and manic or hypomanic episodes, yet the pathogenesis of BD has not been fully elucidated. Recent researches have implicated the altered kynurenine (KYN) metabolism involved in the neurobiology of BD. Excessive activation of the immune system also occurs in patients with BD, which further accelerates the KYN pathway for tryptophan metabolism. Changes of the KYN metabolites have effects on neuronal receptors and are involved in neuroendocrine transmissions. Interactions between KYN metabolism and the immune system may contribute to the neuropathogenesis of BD. Various studies have shown that alterations of the KYN metabolites were associated with mood, psychotic symptoms, and cognitive functions in patients with BD. In this review, we briefly introduce the KYN pathway and describe the immune dysregulation in BD as well as their interactions. We then focus on the research advances on the KYN metabolism in BD, which hold promise for identifying novel treatment targets in patients stricken with this disorder.

Inflammation in Bipolar Disorder (BD): Identification of new therapeutic targets

Bipolar disorder (BD) is a chronic and cyclic mental disorder, characterized by unusual mood swings between mania/hypomania and depression, raising concern in both scientific and medical communities due to its deleterious social and economic impact. Polypharmacy is the rule due to the partial effectiveness of available drugs. Disease course is often unremitting, resulting in frequent cognitive deficits over time. Despite all research efforts in identifying BD-associated molecular mechanisms, current knowledge remains limited. However, the involvement of inflammation in BD pathophysiology is increasingly consensual, with the immune system and neuroinflammation playing a key role in disease course. Evidence includes altered levels of cytokines and acute-phase proteins, pathological microglial activation, deregulation of Nrf2-Keap1 system and changes in biogenic amines neurotransmitters, whose expression is regulated by TNF-α, a pro-inflammatory cytokine highly involved in BD, pointing out inflammation as a novel and attractive therapeutic target for BD. As result, new therapeutic agents including non-steroidal anti-inflammatory drugs, N-acetylcysteine and GSK3 inhibitors have been incorporated in BD treatment. Taking into consideration the latest pre-clinical and clinical trials, in this review we discuss recent data regarding inflammation in BD, unveiling potential therapeutic approaches through direct or indirect modulation of inflammatory response.

Interleukin-6 and total antioxidant capacity levels following N-acetylcysteine and a combination nutraceutical intervention in a randomised controlled trial for bipolar disorder

OBJECTIVE

The aims of this study were to evaluate changes in inflammatory and oxidative stress levels following treatment with N-acetylcysteine (NAC) or mitochondrial-enhancing agents (CT), and to assess the how these changes may predict and/or moderate clinical outcomes primarily the Montgomery-Åsberg Depression Rating Scale (MADRS).

METHODS

This study involved secondary analysis of a placebo-controlled randomised trial (n = 163). Serum samples were collected at baseline and week 16 of the clinical trial to determine changes in Interleukin-6 (IL-6) and total antioxidant capacity (TAC) following adjunctive CT and/or NAC treatment, and to explore the predictability of the outcome or moderator effects of these markers.

RESULTS

In the NAC-treated group, no difference was observed in serum IL-6 and TAC levels after 16 weeks of treatment with NAC or CT. However, results from a moderator analysis showed that in the CT group, lower IL-6 levels at baseline was a significant moderator of MADRS χ2 (df) = 4.90, p = 0.027) and Clinical Global Impression-Improvement (CGI-I, χ2 (df) = 6.28 p = 0.012). In addition, IL-6 was a non-specific but significant predictor of functioning (based on the Social and Occupational Functioning Assessment Scale (SOFAS)), indicating that individuals with higher IL-6 levels at baseline had a greater improvement on SOFAS regardless of their treatment (p = 0.023).

CONCLUSION

Participants with lower IL-6 levels at baseline had a better response to the adjunctive treatment with the mitochondrial-enhancing agents in terms of improvements in MADRS and CGI-I outcomes.

[Neopterin as a potential biomarker in neuropsychiatry]

The importance of finding predictors or biomarkers of neuropsychiatric pathology, as well as methods of its prevention, treatment and early diagnosis is beyond question. The level of neopterin in body fluids is one of the possible biomarkers. Increased levels of neopterin in biological fluids (e.g., serum, cerebrospinal fluid or urine) are closely associated with various diseases associated with cellular immune response. The data presented in the review indicate the relevance of the study of neopterin concentrations in body fluids in patients with mental illness for the development of diagnostic and prognostic tests or as a pharmacodynamic marker of drug action.

The Gut Microbiome in Bipolar Disorder and Pharmacotherapy Management

The gut microbiome is a complex and dynamic community of commensal, symbiotic, and pathogenic microorganisms that exist in a bidirectional relationship with the host. Bacterial functions in the gut play a critical role in healthy host functioning, and its disruption can contribute to many medical conditions. The relationship between gut microbiota and the brain has gained attention in mental health due to the mounting evidence supporting the association of gut bacteria with mood and behavior. Patients with bipolar disorder exhibit an increased frequency of gastrointestinal illnesses such as inflammatory bowel disease, which mechanistically has been linked to microbial community function. While the heterogeneity in microbial communities between individuals might be associated with disease risk, it may also moderate the efficacy or adverse effects associated with the use of medication. The following review highlights published evidence linking the function of gut microbiota both to bipolar disorder risk and to the effect of medications that influence microbiota, inflammation, and mood symptoms.

Construction of a nitro-oxidative stress-driven, mechanistic model of mood disorders: A nomothetic network approach

Major depression is accompanied by increased IgM-mediated autoimmune responses to oxidative specific epitopes (OSEs) and nitric oxide (NO)-adducts. These responses were not examined in bipolar disorder type 1 (BP1) and BP2. IgM responses to malondialdehyde (MDA), phosphatidinylinositol, oleic acid, azelaic acid, and NO-adducts were determined in 35 healthy controls, and 47 major depressed (MDD), 29 BP1, and 25 BP2 patients. We also measured serum peroxides, IgG to oxidized LDL (oxLDL), and IgM/IgA directed to lipopolysaccharides (LPS). IgM responses to OSEs and NO-adducts (OSENO) were significantly higher in MDD and BP1 as compared with controls, and IgM to OSEs higher in MDD than in BP2. Partial Least Squares (PLS) analysis showed that 57.7% of the variance in the clinical phenome of mood disorders was explained by number of episodes, a latent vector extracted from IgM to OSENO, IgG to oxLDL, and peroxides. There were significant specific indirect effects of IgA/IgM to LPS on the clinical phenome, which were mediated by peroxides, IgM OSENO, and IgG oxLDL. Using PLS we have constructed a data-driven nomothetic network which ensembled causome (increased plasma LPS load), adverse outcome pathways (namely neuro-affective toxicity), and clinical phenome features of mood disorders in a data-driven model. Based on those feature sets, cluster analysis discovered a new diagnostic class characterized by increased plasma LPS load, peroxides, autoimmune responses to OSENO, and increased phenome scores. Using the new nomothetic network approach, we constructed a mechanistically transdiagnostic diagnostic class indicating neuro-affective toxicity in 74.3% of the mood disorder patients.