Integrated neurobiology of bipolar disorder

Adaptive Hyperactivity and Biomarker Exploration: Insights from Elders in the Blue Zone of Sardinia

Background/Objectives: Adaptive hyperactivity characterized by increased activity levels and novelty-seeking traits without mood disorders is prevalent among older adults in Sardinia's "blue zone," an area with high longevity. This study aims to evaluate the adaptive nature of hyperactivity concerning quality of life, social rhythms, and mood symptoms in individuals from this region, particularly among elderly adults over 80. Methods: This observational cross-sectional study included adults and older adults over 80 from Sardinia's blue zone. This study included a sample of patients followed at the Center for Consultation Psychiatry and Psychosomatics for Bipolar Disorder of the University Hospital of Cagliari and a homogeneous comparison sample of patients without psychiatric pathologies, referred to the Dermatology Clinic of the same hospital, for a period of 6 months, from February to August 2024. The general sample, divided into two parts-cases, represented by patients with psychiatric pathology, and controls, patients without psychiatric pathology-was divided in turn into three sub-groups: "adults" (18-64 years), young elders (65-79), and old elders (over 80 years). The participants underwent psychiatric interviews and completed the Mood Disorder Questionnaire (MDQ), Patient Health Questionnaire (PHQ-9), SF-12, and Brief Social Rhythm Scale (BSRS). Data were compared with national and regional normative data. Results: Older adults in the blue zone demonstrated higher MDQ positivity (22.58%) compared to the national averages (0.87%), without corresponding increases in dysregulated rhythms, depressive symptoms, or reduced quality of life. Younger old persons (65-79 years) showed increased rhythm dysregulation (BSRS score: 20.64 ± 7.02) compared to adults (17.40 ± 6.09, p = 0.040), but this trend was not observed in the oldest group (80+ years). No significant differences were found in the CH3SH and (CH3)2S levels between groups. Conclusions: The hyperactivity observed in older adults from Sardinia's blue zone appears adaptive and not linked to social rhythm dysregulation, depressive symptoms, or a diminished quality of life, suggesting resilience factors which may contribute to longevity. These findings support the potential classification of such hyperactivity as beneficial rather than pathological, warranting further research into biomarkers and psychoeducational interventions to prevent the onset of bipolar disorders in predisposed individuals.

Abnormal Dynamic Reconfiguration of Multilayer Temporal Networks in Patients with Bipolar Disorder

BACKGROUND

Multilayer networks have been used to identify abnormal dynamic reconfiguration in bipolar disorder (BD). However, these studies ignore the differences in information interactions between adjacent layers when constructing multilayer networks, and the analysis of dynamic reconfiguration is not comprehensive enough; Methods: Resting-state functional magnetic resonance imaging data were collected from 46 BD patients and 54 normal controls. A multilayer temporal network was constructed for each subject, and inter-layer coupling of different nodes was considered using network similarity. The promiscuity, recruitment, and integration coefficients were calculated to quantify the different dynamic reconfigurations between the two groups; Results: The global inter-layer coupling, recruitment, and integration coefficients were significantly lower in BD patients. These results were further observed in the attention network and the limbic/paralimbic and subcortical network, reflecting reduced temporal stability, intra- and inter-subnetwork communication abilities in BD patients. The whole-brain promiscuity was increased in BD patients. The same results were observed in the somatosensory/motor and auditory network, reflecting more functional interactions; Conclusions: This study discovered abnormal dynamic interactions of BD from the perspective of dynamic reconfiguration, which can help to understand the pathological mechanisms of BD.

Adverse Effects of Deep Brain Stimulation for Treatment-Resistant Depression: A Scoping Review

Deep brain stimulation (DBS) is an emerging therapy for treatment-resistant depression (TRD). Although adverse effects have been reported in early-phase and a few randomized clinical trials, little is known about its overall safety profile, which has been assumed to be similar to that of DBS for movement disorders. The objective of this study was to pool existing safety data on DBS for TRD. Following PRISMA guidelines, PubMed was searched for English articles describing adverse outcomes after DBS for TRD. Studies were included if they reported at least 5 patients with a minimal follow-up of 6 months. After abstract (n = 607) and full-article review (n = 127), 28 articles reporting on 353 patients met criteria for final inclusion. Follow-up of the studies retrieved ranged from 12 to 96 months. Hemorrhages occurred in 0.8% of patients and infections in 10.2%. The rate of completed suicide was 2.5%. Development or worsening of depressive symptoms, anxiety, and mania occurred in 18.4%, 9.1%, and 5.1%, respectively. There were some differences between targets, but between-study heterogeneity precluded statistical comparisons. In conclusion, DBS for TRD is associated with surgical and psychiatric adverse events. Hemorrhage and infection occur at rates within an accepted range for other DBS applications. The risk of suicide after DBS for TRD is 2.5% but may not represent a significant deviation from the natural history of TRD. Finally, risks of worsening depression, anxiety, and the incidence of mania should be acknowledged when considering DBS for TRD.

Single-cell multiomics analysis reveals cell/tissue-specific associations in bipolar disorder

This study investigates the cellular origin and tissue heterogeneity in bipolar disorder (BD) by integrating multiomics data. Four distinct datasets were employed, including single-cell RNA sequencing (scRNA-seq) data (embryonic and fetal brain, n = 8, 1,266 cells), BD Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) data (adult brain, n = 210), BD bulk RNA-seq data (adult brain, n = 314), and BD genome-wide association study (GWAS) summary data (n = 413,466). The integration of scRNA-seq data with multiomics data relevant to BD was accomplished using the single-cell disease relevance score (scDRS) algorithm. We have identified a novel brain cell cluster named ADCY1, which exhibits distinct genetic characteristics. From a high-resolution genetic perspective, glial cells emerge as the primary cytopathology associated with BD. Specifically, astrocytes were significantly related to BD at the RNA-seq level, while microglia showed a strong association with BD across multiple panels, including the transcriptome-wide association study (TWAS), ATAC-seq, and RNA-seq. Additionally, oligodendrocyte precursor cells displayed a significant association with BD in both ATAC-seq and RNA-seq panel. Notably, our investigation of brain regions affected by BD revealed significant associations between BD and all three types of glial cells in the dorsolateral prefrontal cortex (DLPFC). Through comprehensive analyses, we identified several BD-associated genes, including CRMP1, SYT4, UCHL1, and ZBTB18. In conclusion, our findings suggest that glial cells, particularly in specific brain regions such as the DLPFC, may play a significant role in the pathogenesis of BD. The integration of multiomics data has provided valuable insights into the etiology of BD, shedding light on potential mechanisms underlying this complex psychiatric disorder.

Lithium response in bipolar disorder: Epigenome-wide DNA methylation signatures and epigenetic aging

Lithium (Li) is the first-line treatment for bipolar disorder (BD) even though only 30 % of BD patients are considered excellent responders. The mechanisms by which Li exerts its action are not clearly understood, but it has been suggested that specific epigenetic mechanisms, such as methylation processes, may play a role. In this regard, DNA methylation patterns can be used to estimate epigenetic age (EpiAge), which is accelerated in BD patients and reversed by Li treatment. Our first aim was to compare the DNA methylation profile in peripheral blood between BD patients categorized as excellent responders to Li (Ex-Rp) and non-responders (N-Rp). Secondly, EpiAge was estimated to detect differential age acceleration between the two groups. A total of 130 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) between Ex-Rp (n = 26) and N-Rp (n = 37) were identified (FDR adjusted p-value < 0.05). We found 122 genes mapping the DMPs and DMRs, nine of which (HOXB6, HOXB3, HOXB-AS3, TENM2, CACNA1B, ANK3, EEF2K, CYP1A1, and SORCS2) had previously been linked to Li response. We found genes related to the GSK3β pathway to be highly represented. Using FUMA, we found enrichment in Gene Ontology Cell Component for the synapse. Gene network analysis highlighted functions related to the cell cycle, nervous system development and function, and gene expression. No significant differences in age acceleration were found between Ex-Rp and N-Rp for any of the epigenetic clocks analysed. Our findings indicate that a specific methylation pattern could determine the response to Li in BD patients. We also found that a significant portion of the differentially methylated genes are closely associated with the GSK3β pathway, reinforcing the role of this system in Li response. Future longitudinal studies with larger samples will help to elucidate the epigenetic mechanisms underlying Li response.

Risk of Pediatric Bipolar Disorder After General Anesthesia in Infants and Toddlers: A Propensity Score-Matched Population-Based Cohort Study

BACKGROUND AND HYPOTHESIS

The potential role of anesthesia as an independent risk factor for childhood bipolar disorder (BD) remains unclear. To address this, we conducted a population-based cohort study employing propensity score matching to compare BD incidence between pediatric patients undergoing surgery with and without general anesthesia.

STUDY DESIGN

Our study included patients aged 0-3 years who received at least 1 episode of general anesthesia and were hospitalized for over 1 day in Taiwan between January 2004 and December 2014. They were matched 1:1 with a population not receiving general anesthesia to assess pediatric BD incidence.

STUDY RESULTS

The study cohort comprised 15 070 patients, equally distributed between the general anesthesia and nongeneral anesthesia groups (7535 each). Multivariate Cox regression analysis revealed adjusted hazard ratios (aHRs; 95% CIs) for pediatric BD in the general anesthesia group as 1.26 (1.04-1.54; P = .021) compared to the nongeneral anesthesia group. Moreover, the incidence rate ratio (95% CI) for the general anesthesia group was 1.26 (1.03-1.53) compared to the nongeneral anesthesia group.

CONCLUSIONS

Early childhood exposure to general anesthesia is significantly associated with an increased risk of pediatric BD. This expands understanding of pediatric BD's complex development, informing preventive strategies, and enhancing mental health outcomes for vulnerable young patients and global pediatric healthcare.

Associations between dietary habits and bipolar disorder: a diet-wide mendelian randomization study

Background

Diet/nutrition is critically important in the pathogenesis, progression, and treatment outcomes of various mental disorders. Current research predominantly focuses on the role of diet in the development and treatment of depression, with less attention given to the relationship between diet and Bipolar Disorder (BD).

Method

We employed Mendelian Randomization (MR) to investigate the relationship between 28 dietary habits and BD. An analysis was conducted using publicly available genome-wide association study data from the UK Biobank dataset. Various dietary habits were analyzed as exposures with BD as the outcome, mainly using the Inverse Variance Weighted (IVW) method.

Results

Intake of non-oily fish and sponge pudding both have a positive association with BD. Oily fish, dried fruit, apples, salt, and cooked vegetables intake also appeared potentially risky for BD, although the possibility of false positives cannot be ruled out. Sensitivity analysis further confirmed the robustness of these findings.

Conclusion

Our research provides evidence of a relationship between various dietary habits and BD. It underscores the need for careful dietary management and balance to reduce the risk of BD, suggesting caution with dietary preferences for fish and sponge pudding. Furthermore, more detailed studies are needed to further understand the potential impacts of high-sugar and high-protein diets on BD development.

Similar imaging changes and their relations to genetic profiles in bipolar disorder across different clinical stages

Bipolar disorder (BD) across different clinical stages may present shared and distinct changes in brain activity. We aimed to reveal the neuroimaging homogeneity and heterogeneity of BD and its relationship with clinical variables and genetic variations. In present study, we conducted fractional amplitude of low-frequency fluctuations (fALFF), functional connectivity (FC) and genetic neuroimaging association analyses with 32 depressed, 26 manic, 35 euthymic BD patients and 87 healthy controls (HCs). Significant differences were found in the bilateral pre/subgenual anterior cingulate cortex (ACC) across the four groups, and all bipolar patients exhibited decreased fALFF values in the ACC when compared to HCs. Furthermore, positive associations were significantly observed between fALFF values in the pre/subgenual ACC and participants' cognitive functioning. No significant changes were found in ACC-based FC. We identified fALFF-alteration-related genes in BD, with enrichment in biological progress including synaptic and ion transmission. Taken together, abnormal activity in ACC is a characteristic change associated with BD, regardless of specific mood stages, serving as a potential neuroimaging feature in BD patients. Our genetic neuroimaging association analysis highlights possible heterogeneity in biological processes that could be responsible for different clinical stages in BD.

Lithium response in bipolar disorder is associated with focal adhesion and PI3K-Akt networks: a multi-omics replication study

Lithium is the gold standard treatment for bipolar disorder (BD). However, its mechanism of action is incompletely understood, and prediction of treatment outcomes is limited. In our previous multi-omics study of the Pharmacogenomics of Bipolar Disorder (PGBD) sample combining transcriptomic and genomic data, we found that focal adhesion, the extracellular matrix (ECM), and PI3K-Akt signaling networks were associated with response to lithium. In this study, we replicated the results of our previous study using network propagation methods in a genome-wide association study of an independent sample of 2039 patients from the International Consortium on Lithium Genetics (ConLiGen) study. We identified functional enrichment in focal adhesion and PI3K-Akt pathways, but we did not find an association with the ECM pathway. Our results suggest that deficits in the neuronal growth cone and PI3K-Akt signaling, but not in ECM proteins, may influence response to lithium in BD.

Healthcare resource utilization and costs associated with first versus subsequent use of cariprazine for bipolar I disorder

AIMS

To evaluate the healthcare resource utilization (HRU) and costs of patients who initiated cariprazine as their first versus subsequent atypical antipsychotic (AA) following a bipolar I disorder (BP-I) diagnosis.

METHODS

Adults with a BP-I diagnosis (first claim = index), commercial, Medicare Supplemental, or Medicaid insurance, and ≥1 outpatient cariprazine dispensing were identified from Merative MarketScan database. Cohorts included patients who initiated cariprazine as either their first or subsequent AA after initial BP-I diagnosis. Characteristics were balanced between cohorts using inverse probability of treatment weighting (IPTW). Outcomes evaluated post-index included all-cause and mental health (MH)-related HRU (hospitalizations, emergency department [ED] visits, outpatient visits), total healthcare costs (medical + pharmacy), and treatment patterns. HRU and healthcare costs were reported per patient-year (PPY) and compared between cohorts using rate ratios and 95% CIs estimated using nonparametric bootstrap procedures. Treatment patterns were analyzed descriptively, with standardized differences ≥10% considered important.

RESULTS

After IPTW, cohorts included 1,409 patients who initiated cariprazine first and 1,621 patients who initiated cariprazine subsequently; the average (standard deviation, SD) observation period was 678 (373) and 758 (389) days for first and subsequent initiators, respectively. Patients who initiated cariprazine first had 23% fewer all-cause hospitalizations and 28% fewer MH-related hospitalizations PPY (each comparison, p < 0.001). Rates of all-cause and MH-related outpatient visits were significantly lower in patients who initiated cariprazine first versus subsequently (each comparison, p < 0.001), while rates of ED visits were similar. Relative to subsequent initiators, first initiators incurred $2,587 and $2,130 lower all-cause and MH-related total healthcare costs PPY, respectively (each comparison, p < 0.05). Before starting cariprazine, first initiators used fewer BP-I-related medications on average than subsequent initiators (2.6 vs 3.9; standardized difference = 23.9%).

LIMITATIONS

Potential coding inaccuracies and residual confounding.

CONCLUSIONS

In this real-world database analysis, patients with BP-I who initiated cariprazine as their first AA had lower rates of HRU and incurred lower costs than patients who initiated cariprazine as a subsequent AA.

Lithium Response in Bipolar Disorder is Associated with Focal Adhesion and PI3K-Akt Networks: A Multi-omics Replication Study

Lithium is the gold standard treatment for bipolar disorder (BD). However, its mechanism of action is incompletely understood, and prediction of treatment outcomes is limited. In our previous multi-omics study of the Pharmacogenomics of Bipolar Disorder (PGBD) sample combining transcriptomic and genomic data, we found that focal adhesion, the extracellular matrix (ECM), and PI3K-Akt signaling networks were associated with response to lithium. In this study, we replicated the results of our previous study using network propagation methods in a genome-wide association study of an independent sample of 2,039 patients from the International Consortium on Lithium Genetics (ConLiGen) study. We identified functional enrichment in focal adhesion and PI3K-Akt pathways, but we did not find an association with the ECM pathway. Our results suggest that deficits in the neuronal growth cone and PI3K-Akt signaling, but not in ECM proteins, may influence response to lithium in BD.

Pushing the Frontiers: Optogenetics for Illuminating the Neural Pathophysiology of Bipolar Disorder

Bipolar disorder (BD), a disabling mental disorder, is featured by the oscillation between episodes of depression and mania, along with disturbance in the biological rhythms. It is on an urgent demand to identify the intricate mechanisms of BD pathophysiology. Based on the continuous progression of neural science techniques, the dysfunction of circuits in the central nervous system was currently thought to be tightly associated with BD development. Yet, challenge exists since it depends on techniques that can manipulate spatiotemporal dynamics of neuron activity. Notably, the emergence of optogenetics has empowered researchers with precise timing and local manipulation, providing a possible approach for deciphering the pathological underpinnings of mental disorders. Although the application of optogenetics in BD research remains preliminary due to the scarcity of valid animal models, this technique will advance the psychiatric research at neural circuit level. In this review, we summarized the crucial aberrant brain activity and function pertaining to emotion and rhythm abnormities, thereby elucidating the underlying neural substrates of BD, and highlighted the importance of optogenetics in the pursuit of BD research.

Role of microtubule actin crosslinking factor 1 (MACF1) in bipolar disorder pathophysiology and potential in lithium therapeutic mechanism

Bipolar affective disorder (BPAD) are life-long disorders that account for significant morbidity in afflicted patients. The etiology of BPAD is complex, combining genetic and environmental factors to increase the risk of disease. Genetic studies have pointed toward cytoskeletal dysfunction as a potential molecular mechanism through which BPAD may arise and have implicated proteins that regulate the cytoskeleton as risk factors. Microtubule actin crosslinking factor 1 (MACF1) is a giant cytoskeletal crosslinking protein that can coordinate the different aspects of the mammalian cytoskeleton with a wide variety of actions. In this review, we seek to highlight the functions of MACF1 in the nervous system and the molecular mechanisms leading to BPAD pathogenesis. We also offer a brief perspective on MACF1 and the role it may be playing in lithium's mechanism of action in treating BPAD.

When the microbiome helps the brain-current evidence

The gut microbiota-brain axis has been recognized as a network of connections that provides communication between the gut microflora and both central and autonomic nervous system. The gut microbiota alteration has been targeted for therapy in various neurodegenerative and psychiatric disbalances. Psychobiotics are probiotics that contribute beneficially to the brain function and the host mental health as a result of an interaction with the commensal gut bacteria, although their mechanism of action has not been completely revealed. In this state-of-art review, the findings about the potential therapeutic effects of the psychobiotics alone or in combination with conventional medicine in the treatment of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, as well as in some psychiatric diseases like depression, schizophrenia, and bipolar disorder, have been summarized. The evidence of the psychobiotics therapeutic outcomes obtained in preclinical and clinical trials have been given respectively for the observed neurodegenerative and psychiatric disorders.

Activation of Mast Cells by Neuropeptides: The Role of Pro-Inflammatory and Anti-Inflammatory Cytokines

Mast cells (MCs) are tissue cells that are derived from bone marrow stem cells that contribute to allergic reactions, inflammatory diseases, innate and adaptive immunity, autoimmunity, and mental disorders. MCs located near the meninges communicate with microglia through the production of mediators such as histamine and tryptase, but also through the secretion of IL-1, IL-6 and TNF, which can create pathological effects in the brain. Preformed chemical mediators of inflammation and tumor necrosis factor (TNF) are rapidly released from the granules of MCs, the only immune cells capable of storing the cytokine TNF, although it can also be produced later through mRNA. The role of MCs in nervous system diseases has been extensively studied and reported in the scientific literature; it is of great clinical interest. However, many of the published articles concern studies on animals (mainly rats or mice) and not on humans. MCs are known to interact with neuropeptides that mediate endothelial cell activation, resulting in central nervous system (CNS) inflammatory disorders. In the brain, MCs interact with neurons causing neuronal excitation with the production of neuropeptides and the release of inflammatory mediators such as cytokines and chemokines. This article explores the current understanding of MC activation by neuropeptide substance P (SP), corticotropin-releasing hormone (CRH), and neurotensin, and the role of pro-inflammatory cytokines, suggesting a therapeutic effect of the anti-inflammatory cytokines IL-37 and IL-38.

BDNF rs6265 differentially influences neurometabolites in the anterior cingulate of healthy and bipolar disorder subjects

Brain-derived neurotrophic factor (BDNF) is the most abundant brain neurotrophin and plays a critical role in neuronal growth, survival and plasticity, implicated in the pathophysiology of Bipolar Disorders (BD). The single-nucleotide polymorphism in the BDNF gene (BDNF rs6265) has been associated with decreased hippocampal BDNF secretion and volume in met carriers in different populations, although the val allele has been reported to be more frequent in BD patients. The anterior cingulate cortex (ACC) is a key center integrating cognitive and affective neuronal connections, where consistent alterations in brain metabolites such as Glx (Glutamate + Glutamine) and N-acetylaspartate (NAA) have been consistently reported in BD. However, little is known about the influence of BDNF rs6265 on neurochemical profile in the ACC of Healthy Controls (HC) and BD subjects. The aim of this study was to assess the influence of BDNF rs6265 on ACC neurometabolites (Glx, NAA and total creatine- Cr) in 124 euthymic BD type I patients and 76 HC, who were genotyped for BDNF rs6265 and underwent a 3-Tesla proton magnetic resonance imaging and spectroscopy scan (¹ H-MRS) using a PRESS ACC single-voxel (8cm³) sequence. BDNF rs6265 polymorphism showed a significant two-way interaction (diagnosis × genotype) in relation to NAA/Cr and total Cr. While met carriers presented increased NAA/Cr in HC, BD-I subjects with the val allele revealed higher total Cr, denoting an enhanced ACC metabolism likely associated with increased glutamatergic metabolites observed in BD-I val carriers. However, these results were replicated only in men. Therefore, our results support evidences that the BDNF rs6265 polymorphism exerts a complex pleiotropic effect on ACC metabolites influenced by the diagnosis and sex.

Pharmacological Strategies for Bipolar Disorders in Acute Phases and Chronic Management with a Special Focus on Lithium, Valproic Acid, and Atypical Antipsychotics

Bipolar disorders (BDs) are a heterogeneous group of severe affective disorders generally described by the alternation of (hypo)manic, depressive, and mixed phases, with euthymic intervals of variable duration. BDs are burdened with high psychiatric and physical comorbidity, increased suicide risk and reduced life expectancy. In addition, BDs can progress into complicated forms (e.g., mixed states, rapid/irregular cycling), which are more difficult to treat and often require personalized pharmacological combinations. Mood stabilizers, particularly Lithium and Valproic acid (VPA), still represent the cornerstones of both acute and chronic pharmacotherapies of BDs. Lithium is the gold standard in BD-I and BDII with typical features, while VPA seems more effective for atypical forms (e.g., mixed-prevalence and rapid-cycling). However, despite appropriate mood stabilization, many patients show residual symptoms, and more than a half recur within 1-2 years, highlighting the need of additional strategies. Among these, the association of atypical antipsychotics (AAPs) with mood stabilizers is recurrent in the treatment of acute phases, but it is also being growingly explored in the maintenance pharmacotherapy. These combinations are clinically more aggressive and often needed in the acute phases, whereas simplifying pharmacotherapies to mood stabilizers only is preferable in the long-term, whenever possible. When mood stabilizers are not enough for maintenance treatment, Quetiapine and, less consistently, Aripiprazole have been proposed as the most advisable adjunctive strategies, for their safety and tolerability profiles. However, in view of the increased risk of serious adverse effects, a careful patient-centered balance between costs and benefits is mandatory.

Prefrontally modulated vagal neuroimmunomodulation is associated with telomere length

Background

Accumulated senescent cells are proposed to be one of the main drivers of age-related pathology such as dementia and cancer through disruption of tissue structure and function. We recently proposed the Neuro-Immuno-Senescence Integrative Model (NISIM), which relates prefrontally modulated vagal tone and subsequent balance between vagal and sympathetic input to the spleen to inflammatory responses leading to generation of reactive oxygen species and oxidative telomere damage.

Aim

In this study, we assess inflammation as a mediator in the relationship between prefrontally modulated vagal tone and leukocyte telomere length (LTL). We also assess the relationship between a recently proposed index of vagal neuroimmunomodulation (vagal tone/inflammation ratio; NIM index) and telomere length.

Methods

This study uses participant data from a large nationally representative longitudinal study since 1974 with a total of 45,000 Norwegian residents so far. A sub-sample of 131 participants from which ultrashort recordings (30 s) of vagal tone, c reactive protein, and LTL could be obtained were included in the study. Relationships were analyzed with Pearson's correlations and hierarchical multiple linear regression using either vagal tone and CRP or the NIM index to predict telomere length.

Results

Vagal tone was a significant positive predictor of telomere length but this was not mediated by c reactive protein, even after controlling for confounders. The NIM index was a significant positive predictor of telomere length, also when controlling for confounders. In a follow-up analysis simultaneously comparing telomere length between groups with high and low values of vagal tone, and between groups with high and low NIM index values, telomere length was only significantly different between NIM index groups.

Conclusion

This is the first study suggesting that prefrontally modulated vagal neuroimmunomodulation is associated with telomere length thus supporting the NISIM. Results indicate that the NIM index is a more sensitive indicator of vagal neuroimmunomodulation than vagal tone and CRP in isolation.

Elevation of C-reactive protein in adolescent bipolar disorder vs. anxiety disorders

Bipolar disorder (BD) largely begins in adolescence, but diagnosis lags for years, causing significant morbidity and mortality, and demonstrating the need for better diagnostic tools. Suggesting an association between BD and immune activity, elevated levels of peripheral inflammatory markers, including C-reactive protein (CRP), have been found in adults with BD. As similar data are extremely limited in adolescents, this study examined CRP levels in adolescents with BD (n = 37) compared to those with anxiety disorders (ADs, n = 157) and healthy controls with no psychiatric diagnoses (HCs, n = 2760). CRP blood levels for patients aged 12-17 years were retrieved from a nationwide repository of deidentified clinical data. After excluding patients with inflammatory conditions, differences in CRP were examined using multivariate and weighted regressions (covariates: demographics and BMI). Mean CRP levels were significantly elevated in adolescents with BD relative to those with ADs and HCs. Mean CRP levels were lower in the ADs cohort versus HCs. Although CRP levels were significantly higher in males and younger patients, the significant between-cohort differences in CRP remained after controlling for multiple confounders. To our knowledge, our study is the first to compare CRP levels between adolescent BD, ADs, and HCs, comprising a novel and essential contribution. Our results suggest the presence of a unique immune process in adolescents with BD and indicate that CRP may represent a biomarker with a crucial role in the diagnostic assessment of adolescent BD.

Data-driven learning to identify biomarkers in bipolar disorder

BACKGROUND AND OBJECTIVE

Bipolar disorder (BD) is one of the primary causes of disability globally and can be easily misdiagnosed as schizophrenia or major depression due to their similar symptoms. Hence, it is of great significance to explore the pathogenesis of BD. Statistical analysis is currently the most common method for exploring the neuropathological mechanisms of psychiatric disorders. However, this method only considers the relationship between groups and does not reflect the individual-level diagnosis. Therefore, we developed machine learning algorithms to measure pathological brain changes in psychiatric disorders.

METHODS

An autoencoder and a feature selection method are proposed to identify the abnormal structural patterns of BD in this study. The autoencoder was constructed using structural imaging data from 1113 healthy controls, which aims to define the normal range of anatomical deviations to distinguish healthy individuals from BD patients. The biomarkers of BD were identified by the reconstruction errors in each brain region. The proposed feature selection (FS)-select framework aimed to determine the optimal FS method and identify the most reproducible feature associated with BD.

RESULTS

We found that the left orbital region of the middle frontal gyrus had the greatest difference between healthy controls and BD patients using a trained autoencoder. The most reproducible feature was the left orbital region of the middle frontal gyrus by FS-select framework when using the different cross-validation strategies.

CONCLUSIONS

A consistent result was obtained from the above two proposed methods wherein a significant difference between healthy controls and BD patients was identified in the left orbital region of the middle frontal gyrus.

Schizophrenia, Bipolar and Major Depressive Disorders: Overview of Clinical Features, Neurotransmitter Alterations, Pharmacological Interventions, and Impact of Oxidative Stress in the Disease Process

Psychiatric disorders are one of the leading causes of disability worldwide and affect the quality of life of both individuals and the society. The current understanding of these disorders points toward receptor dysfunction and neurotransmitter imbalances in the brain. Treatment protocols are hence oriented toward normalizing these imbalances and ameliorating the symptoms. However, recent literature has indicated the possible role of depleted levels of antioxidants like glutathione (GSH) as well as an alteration in the levels of the pro-oxidant, iron in the pathogenesis of major psychiatric diseases, viz., schizophrenia (Sz), bipolar disorder (BD), and major depressive disorder (MDD). This review aims to highlight the involvement of oxidative stress (OS) in these psychiatric disorders. An overview of the clinical features, neurotransmitter abnormalities, and pharmacological treatments concerning these psychiatric disorders has also been presented. Furthermore, it attempts to synthesize literature from existing magnetic resonance spectroscopy (MRS) and quantitative susceptibility mapping (QSM) studies for these disorders, assessing GSH and iron, respectively. This manuscript is a sincere attempt to stimulate research discussion to advance the knowledge base for further understanding of the pathoetiology of Sz, BD, and MDD.

Integrating biobehavioral information to predict mood disorder suicide risk

The will to live and the ability to maintain one's well-being are crucial for survival. Yet, almost a million people die by suicide globally each year (Aleman and Denys, 2014), making premature deaths due to suicide a significant public health problem (Saxena et al., 2013). The expression of suicidal behaviors is a complex phenotype with documented biological, psychological, clinical, and sociocultural risk factors (Turecki et al., 2019). From a brain disease perspective, suicide is associated with neuroanatomical, neurophysiological, and neurochemical dysregulations of brain networks involved in integrating and contextualizing cognitive and emotional regulatory behaviors. From a symptom perspective, diagnostic measures of dysregulated mood states like major depressive symptoms are associated with over sixty percent of suicide deaths worldwide (Saxena et al., 2013). This paper reviews the neurobiological and clinical phenotypic correlates for mood dysregulations and suicidal phenotypes. We further propose machine learning approaches to integrate neurobiological measures with dysregulated mood symptoms to elucidate the role of inflammatory processes as neurobiological risk factors for suicide.

Appetite-regulating hormones in bipolar disorder: A systematic review and meta-analysis

Impaired hormonal regulation of appetite may contribute to higher cardiovascular risk in bipolar disorder (BD). We performed a systematic review and meta-analysis of studies investigating peripheral blood levels of appetite-regulating hormones in BD and controls. A total of 32 studies were included. Leptin and insulin levels were significantly elevated in patients with BD during euthymia, but not in other mood states. Greater differences in the number of male participants between patients with BD and healthy controls were associated with higher effect size estimates for the levels of insulin. There were significant positive correlations of effect size estimates for the levels of adiponectin with the percentage of individuals with type I BD and duration of BD. Our findings point to the mechanisms underlying high rates of cardiometabolic comorbidities in BD. Moreover, they suggest that investigating hormonal regulation of appetite might help to understand differences in the neurobiology of BD types.

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.

Gut Microbial Dysbiosis and Cognitive Impairment in Bipolar Disorder: Current Evidence

Recent studies have reported that the gut microbiota influences mood and cognitive function through the gut-brain axis, which is involved in the pathophysiology of neurocognitive and mental disorders, including Parkinson’s disease, Alzheimer’s disease, and schizophrenia. These disorders have similar pathophysiology to that of cognitive dysfunction in bipolar disorder (BD), including neuroinflammation and dysregulation of various neurotransmitters (i.e., serotonin and dopamine). There is also emerging evidence of alterations in the gut microbial composition of patients with BD, suggesting that gut microbial dysbiosis contributes to disease progression and cognitive impairment in BD. Therefore, microbiota-centered treatment might be an effective adjuvant therapy for BD-related cognitive impairment. Given that studies focusing on connections between the gut microbiota and BD-related cognitive impairment are lagging behind those on other neurocognitive disorders, this review sought to explore the potential mechanisms of how gut microbial dysbiosis affects cognitive function in BD and identify potential microbiota-centered treatment.

Neural Networks to Recognize Patterns in Topographic Images of Cortical Electrical Activity of Patients with Neurological Diseases

Software such as EEGLab has enabled the treatment and visualization of the tracing and cortical topography of the electroencephalography (EEG) signals. In particular, the topography of the cortical electrical activity is represented by colors, which make it possible to identify functional differences between cortical areas and to associate them with various diseases. The use of cortical topography with EEG origin in the investigation of diseases is often not used due to the representation of colors making it difficult to classify the disease. Thus, the analyses have been carried out, mainly, based on the EEG tracings. Therefore, a computer system that recognizes disease patterns through cortical topography can be a solution to the diagnostic aid. In view of this, this study compared five models of Convolutional Neural Networks (CNNs), namely: Inception v3, SqueezeNet, LeNet, VGG-16 and VGG-19, in order to know the patterns in cortical topography images obtained with EEG, in Parkinson's disease, Depression and Bipolar Disorder. SqueezeNet performed better in the 3 diseases analyzed, with Parkinson's disease being better evaluated for Accuracy (88.89%), Precison (86.36%), Recall (91.94%) and F1 Score (89.06%), the other CNNs had less performance. In the analysis of the values of the Area under ROC Curve (AUC), SqueezeNet reached (93.90%) for Parkinson's disease, (75.70%) for Depression and (72.10%) for Bipolar Disorder. We understand that there is the possibility of classifying neurological diseases from cortical topographies with the use of CNNs and, thus, creating a computational basis for the implementation of software for screening and possible diagnostic assistance.

Correlates of clinical variables on early-stage visual processing in schizophrenia and bipolar disorder

The use of noninvasive tools can help understand mental states and changes that are caused by medications, symptom severity, and other clinical variables. We investigated low-level visual processing using the contrast sensitivity function (CSF), a reliable, robust, and widely used approach. Our main purpose was (1) to evaluate visual impairments in schizophrenia (SCZ) and bipolar disorder (BPD) patients and (2) to investigate associations between clinical variables and visual function in both diseases. Fifty-six healthy controls (HCs; mean age = 31.04 years), 42 BPD patients (mean age = 32.84 years) who took only lithium, and 39 SCZ patients who took only olanzapine (mean age = 32.80 years) were recruited for this study. CSF differed between groups. Both groups of patients exhibited lower discrimination at low, mid-, and high spatial frequencies compared with HCs. No differences were observed between patients, with the exception of high spatial frequency. These impairments were also related to clinical variables, revealed by a strong effect in the mediation analyses. These findings may aid investigations of other clinical variables and the role of state- and trait-like effects on visual and cognitive processing in these patient populations. This study underscores the need for visual remediation interventions.

Shared postulations between bipolar disorder and polycystic ovary syndrome pathologies

INTRODUCTION

Women with bipolar disorder (BD) present a high prevalence of polycystic ovary syndrome (PCOS) and other reproductive disorders even before diagnosis or treatment of the disease. Postulations on the potential molecular mechanisms of comorbid PCOS in women with BD remain limited to influence of medications and need further extension.

OBJECTIVES

This review focuses on evidence suggesting that common metabolic and immune disorders may play an important role in the development of BD and PCOS.

RESULTS

The literature covered in this review suggests that metabolic and immune disorders, including the dysfunction of the hypothalamic-pituitary-adrenal axis, chronic inflammatory state, gut microbial alterations, adipokine alterations and circadian rhythm disturbance, are observed in patients with BD and PCOS. Such disorders may be responsible for the increased prevalence of PCOS in the BD population and indicate a susceptibility gene overlap between the two diseases. Current evidence supports postulations of common metabolic and immune disorders as endophenotype in BD as well as in PCOS.

CONCLUSIONS

Metabolic and immune disorders may be responsible for the comorbid PCOS in the BD population. The identification of hallmark metabolic and immune features common to these two diseases will contribute to the clarification of the effect of BD on the reproductive endocrine function and development of symptomatic treatments targeting the biomarkers of the two diseases.

Treatment-induced mood switching in affective disorders

Many patients under treatment for mood disorders, in particular patients with bipolar mood disorders, experience episodes of mood switching from one state to another. Various hypotheses have been proposed to explain the mechanism of mood switching, spontaneously or induced by drug treatment. Animal models have also been used to test the role of psychotropic drugs in the switching of mood states. We examine the possible relationship between the pharmacology of psychotropic drugs and their reported incidents of induced mood switching, with reference to the various hypotheses of mechanisms of mood switching.

Contribution of Age, Brain Region, Mood Disorder Pathology, and Interindividual Factors on the Methylome of Human Microglia

BACKGROUND

Transcriptome studies have revealed age-, disease-, and region-associated microglial phenotypes reflecting changes in microglial function during development, aging, central nervous system homeostasis, and pathology. The molecular mechanisms that contribute to these transcriptomic changes are largely unknown. The aim of this study was to characterize the DNA methylation landscape of human microglia and the factors that contribute to variations in the microglia methylome. We hypothesized that both age and brain region would have a large impact on DNA methylation in microglia.

METHODS

Microglia from postmortem brain tissue of four different brain regions of 22 donors, encompassing 1 patient with schizophrenia, 13 patients with mood disorder pathology, and 8 control subjects, were isolated and assayed using a genome-wide methylation array.

RESULTS

We found that human microglial cells have a methylation profile distinct from bulk brain tissue and neurons, and age explained a considerable part of the variation. Additionally, we showed that interindividual factors had a much larger effect on the methylation landscape of microglia than brain region, which was also seen at the transcriptome level. In our exploratory analysis, we found various differentially methylated regions that were related to disease status (mood disorder vs. control). This included differentially methylated regions that are linked to gene expression in microglia, as well as to myeloid cell function or neuropsychiatric disorders.

CONCLUSIONS

Although based on relatively small samples, these findings suggest that the methylation profile of microglia is responsive to interindividual variations and thereby plays an important role in the heterogeneity of microglia observed at the transcriptome level.

Altered striatal functional connectivity and structural dysconnectivity in individuals with bipolar disorder: A resting state magnetic resonance imaging study

OBJECTIVE

Bipolar disorder (BD) is a mood swing illness characterized by episodes ranging from depressive lows to manic highs. Although the specific origin of BD is unknown, genetics, environment, and changes in brain structure and chemistry may all have a role. Through magnetic resonance imaging (MRI) evaluations, this study looked into functional abnormalities involving the striatum between BD group and healthy controls (HC), compared the whole-brain gray matter (GM) morphological patterns between the groups and see whether functional connectivity has its underlying structural basis.

MATERIALS AND METHODS

We applied sliding windows to functional magnetic resonance imaging (fMRI) data from 49 BD patients and 44 HCs to generate temporal correlations maps to determine strength and variability of the striatum-to-whole-brain-network functional connectivity (FC) in each window whilst also employing voxel-based morphometry (VBM) to high-resolution structural MRI data to uncover structural differences between the groups.

RESULTS

Our analyses revealed increased striatal connectivity in three consecutive windows 69, 70, and 71 (180, 182, and 184 s) in individuals with BD (p < 0.05; Bonferroni corrected) in fMRI images. Moreover, the VBM findings of structural images showed gray matter (GM) deficits in the left precentral gyrus and middle frontal gyrus of the BD patients (p = 0.001, uncorrected) when compared to HCs. Variability of striatal connectivity did not reveal significant differences between the groups.

CONCLUSION

These findings revealed that BD was associated with a weakening of the precentral gyrus and middle frontal gyrus, also implying that bipolar illness may be linked to striatal functional brain alterations.

The Purinergic System as a Target for the Development of Treatments for Bipolar Disorder

The neurobiological and neurochemical mechanisms underlying the pathophysiology of bipolar disorder are complex and not yet fully understood. From circadian disruption to neuroinflammation, many pathways and signaling molecules are important contributors to bipolar disorder development, some specific to a disease subtype or a cycling episode. Pharmacological agents for bipolar disorder have shown only partial efficacy, including mood stabilizers and antipsychotics. The purinergic hypothesis for bipolar disorder emerges in this scenario as a promising target for further research and drug development, given its role in neurotransmission and neuroinflammation that results in behavioral and mood regulation. Here, we review the basic concepts of purinergic signaling in the central nervous system and its contribution to bipolar disorder pathophysiology. Allopurinol and novel P2X7 receptor antagonists are promising candidates for treating bipolar disorder. We further explore currently available pharmacotherapies and the emerging new purinergic targets for drug development in bipolar disorder.

Sleep markers in psychiatry: do insomnia and disturbed sleep play as markers of disrupted neuroplasticity in mood disorders? A proposed model

INTRODUCTION

Since insomnia and disturbed sleep may affect neuroplasticity, we aimed at reviewing their potential role as markers of disrupted neuroplasticity involved in mood disorders.

METHOD

We performed a systematic review, according to PRIMA, on PubMed, PsycINFO and Embase electronic databases for literature regarding mood disorders, insomnia, sleep loss/deprivation in relation to different pathways involved in the impairment of neuroplasticity in mood disorders such as 1] alterations in neurodevelopment 2] activation of the stress system 3] neuroinflammation 4] neurodegeneration/neuroprogression, 4] deficit in neuroprotection.

RESULTS

Sixty-five articles were analyzed and a narrative/ theoretical review was conducted. Studies showed that insomnia, sleep loss and sleep deprivation might impair brain plasticity of those areas involved in mood regulation throughout different pathways. Insomnia and disrupted sleep may act as neurobiological stressors that by over-activating the stress and inflammatory systems may affect neural plasticity causing neuronal damage. In addition, disturbed sleep may favor a deficit in neuroprotection hence contributing to impaired neuroplasticity.

CONCLUSIONS

Insomnia and disturbed sleep may play a role as markers of alteration in brain plasticity in mood disorders. Assessing and targeting insomnia in the clinical practice may potentially play a neuroprotective role, contributing to "repairing" alterations in neuroplasticity or to the functional recovery of those areas involved in mood and emotion regulation.

Prefrontal-limbic-striatum dysconnectivity associated with negative emotional endophenotypes in bipolar disorder during depressive episodes

BACKGROUND

The prefrontal-limbic-subcortical network has been suggested as an important circuitry in the pathophysiology underlying bipolar disorder during depressive episodes (BDD). However, the relationships between disrupted prefrontal-limbic-subcortical connection and the emotional endophenotypes in BDD patients remain largely unclear.

METHODS

Forty-three BDD patients and 63 matched healthy controls (HCs) underwent the resting-state functional magnetic resonance imaging scan. The altered clusters were first identified by using a spatial pairwise clustering method and then were extracted as regions of interest to calculate the functional connectivity (FC). Group comparisons were conducted to identify the abnormal FCs. Classification analysis was employed to examine whether the altered FCs could distinguish BDD from HCs. The relationships between FC alterations and the emotional endophenotypes as measured by the Affective Neuroscience Personality Scales (ANPS) were further detected in BDD.

RESULTS

Compared with HCs, BDD patients showed abnormal FCs in the prefrontal-limbic-striatum circuit. Importantly, the altered FCs yielded 84.91% accuracy (p< 1/5000) with 93.65% sensitivity and 72.09% specificity in differentiating between BDD and HCs. Moreover, the decreased FCs in the prefrontal-striatum and prefrontal-limbic systems were positively correlated with negative emotional endophenotypes of Sadness and Fear scores.

CONCLUSIONS

The findings demonstrated that prefrontal-limbic-striatum disconnection may be identified as a potential effective biomarker for BDD, which could help further explain the neurobiological mechanisms underlying BDD.

Neutrophil/lymphocyte, platelet/lymphocyte and monocyte/lymphocyte ratios in mood disorders

Major depressive disorder (MDD) and bipolar disorders (BDs), the most severe types of mood disorders (MDs), are considered as among the most disabling illnesses worldwide. Several studies suggested that inflammatory neuroinflammation might be involved in the pathophysiology of MDs, while reporting increasing data on the relationships between these processes and classical neurotransmitters, hypothalamus-pituitary-adrenal axis (HPA), and neurotrophic factors. The assessment of neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) in peripheral blood represents a simple method to evaluate the inflammatory status. The aim of the present paper was to review the literature on the possible relationships between NLR, PLR and MLR in MDs, and to comment on their possible wider use in clinical research. Thirty-five studies were included in the present review. The majority of them higher values of these parameters, particularly NLR values, in patients with MDs, when compared to healthy subjects. The increase would appear more robust in patients with BD during a manic episode, thus indicating that it could be considered as both state and trait markers. In addition, increased NLR and PLR levels seem to represent prognostic elements for the early discovery of post-stroke depression. The findings of the present review would indicate the need to carry our further studies in this field. In particular, NLR, PLR and MLR seem to be promising tools to detect economically and easily the activation of the inflammatory system, and to perhaps evaluate the etiology and course of MDs. Again, they could suggest some information to better understand the relationship between inflammatory and cardiovascular disease and MDs, and thus, to provide clinical implications in terms of management and treatment.

The emerging tale of microglia in psychiatric disorders

As the professional phagocytes of the brain, microglia orchestrate the immunological response and play an increasingly important role in maintaining homeostatic brain functions. Microglia are activated by pathological events or slight alterations in brain homeostasis. This activation is dependent on the context and type of stressor or pathology. Through secretion of cytokines, chemokines and growth factors, microglia can strongly influence the response to a stressor and can, therefore, determine the pathological outcome. Psychopathologies have repeatedly been associated with long-lasting priming and sensitization of cerebral microglia. This review focuses on the diversity of microglial phenotype and function in health and psychiatric disease. We first discuss the diverse homeostatic functions performed by microglia and then elaborate on context-specific spatial and temporal microglial heterogeneity. Subsequently, we summarize microglia involvement in psychopathologies, namely major depressive disorder, schizophrenia and bipolar disorder, with a particular focus on post-mortem studies. Finally, we postulate microglia as a promising novel therapeutic target in psychiatry through antidepressant and antipsychotic treatment.

Exploring Signatures of Neurodegeneration in Early-Onset Older-Age Bipolar Disorder and Behavioral Variant Frontotemporal Dementia

Introduction: Older-age bipolar disorder (OABD) may involve neurocognitive decline and behavioral disturbances that could share features with the behavioral variant of frontotemporal dementia (bvFTD), making the differential diagnosis difficult in cases of suspected dementia. Objective: To compare the neuropsychological profile, brain morphometry, and structural connectivity patterns between patients diagnosed with bvFTD, patients classified as OABD with an early onset of the disease (EO-OABD), and healthy controls (HC). Methods: bvFTD patients (n = 25, age: 66 ± 7, female: 64%, disease duration: 6 ± 4 years), EO-OABD patients (n = 17, age: 65 ± 9, female: 71%, disease duration: 38 ± 8 years), and HC (n = 28, age: 62 ± 7, female: 64%) were evaluated through neuropsychological tests concerning attention, memory, executive function, praxis, and language. Brain morphometry was analyzed through surface-based morphometry (SBM), while structural brain connectivity was assessed through diffusion tensor imaging (DTI). Results: Both bvFTD and EO-OABD patients showed lower performance in neuropsychological tests of attention, verbal fluency, working memory, verbal memory, and praxis than HC. Comparisons between EO-OABD and bvFTD showed differences limited to cognitive flexibility delayed recall and intrusion errors in the memory test. SBM analysis demonstrated that several frontal, temporal, and parietal regions were altered in both bvFTD and EO-OABD compared to HC. In contrast, comparisons between bvFTD and EO-OABD evidenced differences exclusively in the right temporal pole and the left entorhinal cortex. DTI analysis showed alterations in association and projection fibers in both EO-OABD and bvFTD patients compared to HC. Commissural fibers were found to be particularly affected in EO-OABD. The middle cerebellar peduncle and the pontine crossing tract were exclusively altered in bvFTD. There were no significant differences in DTI analysis between EO-OABD and bvFTD. Discussion: EO-OABD and bvFTD may share an overlap in cognitive, brain morphometry, and structural connectivity profiles that could reflect common underlying mechanisms, even though the etiology of each disease can be different and multifactorial.

Valproate reverses mania-like behaviors in mice via preferential targeting of HDAC2

Valproate (VPA) has been used in the treatment of bipolar disorder since the 1990s. However, the therapeutic targets of VPA have remained elusive. Here we employ a preclinical model to identify the therapeutic targets of VPA. We find compounds that inhibit histone deacetylase proteins (HDACs) are effective in normalizing manic-like behavior, and that class I HDACs (e.g., HDAC1 and HDAC2) are most important in this response. Using an RNAi approach, we find that HDAC2, but not HDAC1, inhibition in the ventral tegmental area (VTA) is sufficient to normalize behavior. Furthermore, HDAC2 overexpression in the VTA prevents the actions of VPA. We used RNA sequencing in both mice and human induced pluripotent stem cells (iPSCs) derived from bipolar patients to further identify important molecular targets. Together, these studies identify HDAC2 and downstream targets for the development of novel therapeutics for bipolar mania.

Clozapine: Why Is It So Uniquely Effective in the Treatment of a Range of Neuropsychiatric Disorders?

Clozapine is superior to other antipsychotics as a therapy for treatment-resistant schizophrenia and schizoaffective disorder with increased risk of suicidal behavior. This drug has also been used in the off-label treatment of bipolar disorder, major depressive disorder (MDD), and Parkinson's disease (PD). Although usually reserved for severe and treatment-refractory cases, it is interesting that electroconvulsive therapy (ECT) has also been used in the treatment of these psychiatric disorders, suggesting some common or related mechanisms. A literature review on the applications of clozapine and electroconvulsive therapy (ECT) to the disorders mentioned above was undertaken, and this narrative review was prepared. Although both treatments have multiple actions, evidence to date suggests that the ability to elicit epileptiform activity and alter EEG activity, to increase neuroplasticity and elevate brain levels of neurotrophic factors, to affect imbalances in the relationship between glutamate and γ-aminobutyric acid (GABA), and to reduce inflammation through effects on neuron-glia interactions are common underlying mechanisms of these two treatments. This evidence may explain why clozapine is effective in a range of neuropsychiatric disorders. Future increased investigations into epigenetic and connectomic changes produced by clozapine and ECT should provide valuable information about these two treatments and the disorders they are used to treat.

Proximate and Ultimate Perspectives on Romantic Love

Romantic love is a phenomenon of immense interest to the general public as well as to scholars in several disciplines. It is known to be present in almost all human societies and has been studied from a number of perspectives. In this integrative review, we bring together what is known about romantic love using Tinbergen’s “four questions” framework originating from evolutionary biology. Under the first question, related to mechanisms, we show that it is caused by social, psychological mate choice, genetic, neural, and endocrine mechanisms. The mechanisms regulating psychopathology, cognitive biases, and animal models provide further insights into the mechanisms that regulate romantic love. Under the second question, related to development, we show that romantic love exists across the human lifespan in both sexes. We summarize what is known about its development and the internal and external factors that influence it. We consider cross-cultural perspectives and raise the issue of evolutionary mismatch. Under the third question, related to function, we discuss the fitness-relevant benefits and costs of romantic love with reference to mate choice, courtship, sex, and pair-bonding. We outline three possible selective pressures and contend that romantic love is a suite of adaptions and by-products. Under the fourth question, related to phylogeny, we summarize theories of romantic love’s evolutionary history and show that romantic love probably evolved in concert with pair-bonds in our recent ancestors. We describe the mammalian antecedents to romantic love and the contribution of genes and culture to the expression of modern romantic love. We advance four potential scenarios for the evolution of romantic love. We conclude by summarizing what Tinbergen’s four questions tell us, highlighting outstanding questions as avenues of potential future research, and suggesting a novel ethologically informed working definition to accommodate the multi-faceted understanding of romantic love advanced in this review.

Grey and white matter alteration in euthymic children with bipolar disorder: a combined source-based morphometry (SBM) and voxel-based morphometry (VBM) study

Bipolar disorder (BPD) is a psychiatric condition driving frequent mood swings between periodic extremes of happiness and depression in patients. In this study, a source-based morphometry (SBM) and voxel-based morphometry (VBM) analysis was utilized to measure the differences in the white matter (WM) and grey matter (GM) between euthymic children with BPD and typically developing (TD) children. We adapted both multivariate (SBM) and univariate (VBM) analysis in 20 children with BPD euthymia /remission and compared to the same number of TD age-matched children. The VBM did not reveal any increase in GM and WM voxel values in children with BPD. However, a decrease in the GM voxel values in the bilateral middle frontal and WM voxels in the left hippocampus, left caudate, left orbitofrontal and right inferior parietal cortices was identified. Conversely, SBM analysis in BPD displayed a high GM value in bilateral angular gyrus, bilateral inferior temporal, left supplementary motor area and left middle temporal region, while a low value was observed in left inferior and middle occipital, cerebellum, thalamus, left premotor area and left lingual gyrus. These findings suggested a crucial GM and WM alteration in multiple neural regions in BPD children even during sustained and substantial remission.

Plasma prevalence of anti-N-methyl-d-aspartate receptor IgG antibodies in early stages of psychosis

We investigated the feasibility of including plasma anti-NMDAR antibody screening in the assessment of first-episode psychosis patients in an early intervention programme in the Southern hemisphere. Anti-NMDAR IgG antibodies were assessed by ELISA in 166 patients (64.0% men), 166 matched population-based controls and 76 patients' siblings (30.3% men). Fisher's exact test and ANOVA were performed. Positive anti-NMDAR antibody patients were more often observed in bipolar disorder (10.0%) than schizophrenia (2.4%) or psychotic depression (3.1%), although no significant differences were observed. Our results are not conclusive regarding the inclusion of plasma anti-NMDAR IgG antibodies in differential diagnostic protocols for psychosis.

Pattern of occurrence of obsessive-compulsive symptoms in bipolar disorder

Apparent comorbidity between Bipolar Disorder (BD) and Obsessive-Compulsive Disorder (OCD) is a common condition, but its meaning has not been clarified yet. The present study aimed to evaluate the pattern of occurrence of obsessive-compulsive symptoms (OCS) in the different phases of BD. One hundred and sixty-five BD patients, 62 (37.5%) euthymic, 34 (20.6%) in hypomanic/manic phase, 43 (26%) in depressive phase and 26 (15.7%) in mixed state, were assessed with the Yale-Brown Obsessive-Compulsive Scale (YBOCS), the Hamilton Depression Rating Scale (HAM-D), the Young Mania Rating Scale (YMRS) and the Ruminative Response Scale (RRS). In the whole sample, the severity of OCS was associated to the severity of depressive symptoms. The highest severity of OCS (YBOCS total score) was observed in the mixed group and the lowest scores in the hypomanic/manic group. Our findings suggest that OCS in BD patients appear as a state-dependent phenomenon cycling with the mood phases, particularly exacerbating in the context of depressive and mixed states.

Transcriptional analysis of sodium valproate in a serotonergic cell line reveals gene regulation through both HDAC inhibition-dependent and independent mechanisms

Sodium valproate (VPA) is a histone deacetylase (HDAC) inhibitor, widely prescribed in the treatment of bipolar disorder, and yet the precise modes of therapeutic action for this drug are not fully understood. After exposure of the rat serotonergic cell line RN46A to VPA, RNA-sequencing (RNA-Seq) analysis showed widespread changes in gene expression. Analysis by four bioinformatic pipelines revealed as many as 230 genes were significantly upregulated and 72 genes were significantly downregulated. A subset of 23 differentially expressed genes was selected for validation using the nCounter® platform, and of these we obtained robust validation for ADAM23, LSP1, MAOB, MMP13, PAK3, SERPINB2, SNAP91, WNT6, and ZCCHC12. We investigated the effect of lithium on this subset and found four genes, CDKN1C, LSP1, SERPINB2, and WNT6 co-regulated by lithium and VPA. We also explored the effects of other HDAC inhibitors and the VPA analogue valpromide on the subset of 23 selected genes. Expression of eight of these genes, CDKN1C, MAOB, MMP13, NGFR, SHANK3, VGF, WNT6 and ZCCHC12, was modified by HDAC inhibition, whereas others did not appear to respond to several HDAC inhibitors tested. These results suggest VPA may regulate genes through both HDAC-dependent and independent mechanisms. Understanding the broader gene regulatory effects of VPA in this serotonergic cell model should provide insights into how this drug works and whether other HDAC inhibitor compounds may have similar gene regulatory effects, as well as highlighting molecular processes that may underlie regulation of mood.

Relationship Between Serum Agouti-Related Peptide Levels and Metabolic Syndrome in Euthymic Bipolar Patients

INTRODUCTION

Agouti-Related Peptide (AgRP) is expressed primarily in the hypothalamic arcuate nucleus, stimulates appetite and decreases metabolism and energy expenditure. The aim of our study is to evaluate the relationship between serum Agouti-Related Peptide (AgRP) levels and metabolic syndrome in euthymic bipolar patients.

METHODS

Forty euthymic bipolar patients who used only mood stabilizer for at least three months and 40 healthy volunteers as control group were included in the study. We measured fasting blood glucose levels and serum levels of AgRP, total cholesterol, triglyceride, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) of all participants. The main outcome measure was the difference between patients and control groups in terms of metabolic syndrome frequency and the relationship between serum AgRP level and metabolic syndrome is also investigated.

RESULTS

The metabolic syndrome was significantly more common in euthymic bipolar patients than in control group (p=0.039). Additionally, levels of blood glucose and triglyceride were significantly higher in the patient group than in the control group (p=0.006 and 0.01 respectively). Serum AgRP levels did not differ between the patient and control groups (p=0.35). Also, in euthymic bipolar patients, there was no significant difference in serum AgRP levels between patients with metabolic syndrome and those without (p=0.754).

CONCLUSION

We found significantly higher frequency of metabolic syndrome in euthymic bipolar patients than in the control group. However, there was no significant difference in the levels of serum AgRP between bipolar patients with and without metabolic syndrome in either study groups.

Reviewing applications of structural and functional MRI for bipolar disorder

Bipolar disorders (BDs) represent one of the leading causes of disability and morbidity globally. The use of functional magnetic resonance imaging (fMRI) is being increasingly studied as a tool to improve the diagnosis and treatment of BDs. While morphological biomarkers can be identified through the use of structural magnetic resonance imaging (sMRI), recent studies have demonstrated that varying degrees of both structural and functional impairments indicate differing bipolar subtypes. Within fMRI, resting-state fMRI has specifically drawn increased interest for its capability to detect different neuronal activation patterns compared to task-based fMRI. This study aims to review recently published literature regarding the use of fMRI to investigate structural-functional relationships in BD diagnosis and specifically resting-state fMRI to provide an opinion on fMRI's modern clinical application. All sources in this literature review were collected through searches on both PubMed and Google Scholar databases for terms such as 'resting-state fMRI' and 'functional neuroimaging biomarkers of bipolar disorder'. While there are promising results supporting the use of fMRI for improving differential accuracy and establishing clinically relevant biomarkers, additional evidence will be required before fMRI is considered a dependable component of the overall BD diagnostic process.

Astroglial cells as neuroendocrine targets in forebrain development: Implications for sex differences in psychiatric disease

Astroglial cells are the most abundant cell type in the mammalian brain. They are implicated in almost every aspect of brain physiology, including maintaining homeostasis, building and maintaining the blood brain barrier, and the development and maturation of neuronal networks. Critically, astroglia also express receptors for gonadal sex hormones, respond rapidly to gonadal hormones, and are able to synthesize hormones. Thus, they are positioned to guide and mediate sexual differentiation of the brain, particularly neuronal networks in typical and pathological conditions. In this review, we describe astroglial involvement in the organization and development of the brain, and consider known sex differences in astroglial responses to understand how astroglial cell-mediated organization may play a role in forebrain sexual dimorphisms in human populations. Finally, we consider how sexually dimorphic astroglial responses and functions in development may lead to sex differences in vulnerability for neuropsychiatric disorders.

The use of a gene expression signature and connectivity map to repurpose drugs for bipolar disorder

To create a gene expression signature (GES) to represent the biological effects of a combination of known drugs for bipolar disorder (BD) on cultured human neuronal cells (NT2-N) and rat brains, which also has evidence of differential expression in individuals with BD. To use the GES to identify new drugs for BD using Connectivity Map (CMap).Methods: NT2-N (n = 20) cells and rats (n = 8) were treated with a BD drug combination (lithium, valproate, quetiapine and lamotrigine) or vehicle for 24 and 6 h, respectively. Following next-generation sequencing, the differential expression of genes was assessed using edgeR in R. The derived GES was compared to differentially expressed genes in post-mortem brains of individuals with BD. The GES was then used in CMap analysis to identify similarly acting drugs.Results: A total of 88 genes showed evidence of differential expression in response to the drug combination in both models, and therefore comprised the GES. Six of these genes showed evidence of differential expression in post-mortem brains of individuals with BD. CMap analysis identified 10 compounds (camptothecin, chlorambucil, flupenthixol, valdecoxib, rescinnamine, GW-8510, cinnarizine, lomustine, mifepristone and nimesulide) acting similarly to the BD drug combination.Conclusions: This study shows that GES and CMap can be used as tools to repurpose drugs for BD.