Neurotrophins, cytokines, oxidative stress mediators and mood state in bipolar disorder: systematic review and meta-analyses

Inflammatory and oxidative stress biomarkers in children and adolescents with bipolar disorder - A systematic review and meta-analysis

Evidence suggests a role for low-grade inflammation and oxidative stress in the pathophysiology of bipolar disorder. We conducted a systematic review and meta-analysis of peripheral markers of inflammation and oxidative stress in children and adolescents under 20 years of age with bipolar disorder. We searched PubMed, Embase and psycINFO and performed random effects meta-analysis calculating standardized mean differences (SMD) of marker levels between patients with bipolar disorder and healthy control individuals. Ten studies comprising a total of 418 patients with bipolar disorder and 3017 healthy control individuals were included. The levels of C-Reactive Protein were higher in patients with bipolar disorder compared with healthy individuals (SMD 0.53; 95 %CI: 0.33-0.74; I2 = 0 %). For other biomarkers there were no statistically significant differences between groups. Findings were limited by a low number of studies and participants and methodological issues in the included studies. More and larger studies using rigorous methodology are needed to establish the role of inflammation and oxidative stress in children and adolescents with bipolar disorder.

Inflammatory mediators in major depression and bipolar disorder

Major depressive disorder (MDD) and bipolar disorder (BD) are highly disabling illnesses defined by different psychopathological, neuroimaging, and cognitive profiles. In the last decades, immune dysregulation has received increasing attention as a central factor in the pathophysiology of these disorders. Several aspects of immune dysregulations have been investigated, including, low-grade inflammation cytokines, chemokines, cell populations, gene expression, and markers of both peripheral and central immune activation. Understanding the distinct immune profiles characterizing the two disorders is indeed of crucial importance for differential diagnosis and the implementation of personalized treatment strategies. In this paper, we reviewed the current literature on the dysregulation of the immune response system focusing our attention on studies using inflammatory markers to discriminate between MDD and BD. High heterogeneity characterized the available literature, reflecting the heterogeneity of the disorders. Common alterations in the immune response system include high pro-inflammatory cytokines such as IL-6 and TNF-α. On the contrary, a greater involvement of chemokines and markers associated with innate immunity has been reported in BD together with dynamic changes in T cells with differentiation defects during childhood which normalize in adulthood, whereas classic mediators of immune responses such as IL-4 and IL-10 are present in MDD together with signs of immune-senescence.

New Advances in the Pharmacology and Toxicology of Lithium: A Neurobiologically Oriented Overview

Over the last six decades, lithium has been considered the gold standard treatment for the long-term management of bipolar disorder due to its efficacy in preventing both manic and depressive episodes as well as suicidal behaviors. Nevertheless, despite numerous observed effects on various cellular pathways and biologic systems, the precise mechanism through which lithium stabilizes mood remains elusive. Furthermore, there is recent support for the therapeutic potential of lithium in other brain diseases. This review offers a comprehensive examination of contemporary understanding and predominant theories concerning the diverse mechanisms underlying lithium's effects. These findings are based on investigations utilizing cellular and animal models of neurodegenerative and psychiatric disorders. Recent studies have provided additional support for the significance of glycogen synthase kinase-3 (GSK3) inhibition as a crucial mechanism. Furthermore, research has shed more light on the interconnections between GSK3-mediated neuroprotective, antioxidant, and neuroplasticity processes. Moreover, recent advancements in animal and human models have provided valuable insights into how lithium-induced modifications at the homeostatic synaptic plasticity level may play a pivotal role in its clinical effectiveness. We focused on findings from translational studies suggesting that lithium may interface with microRNA expression. Finally, we are exploring the repurposing potential of lithium beyond bipolar disorder. These recent findings on the therapeutic mechanisms of lithium have provided important clues toward developing predictive models of response to lithium treatment and identifying new biologic targets. SIGNIFICANCE STATEMENT: Lithium is the drug of choice for the treatment of bipolar disorder, but its mechanism of action in stabilizing mood remains elusive. This review presents the latest evidence on lithium's various mechanisms of action. Recent evidence has strengthened glycogen synthase kinase-3 (GSK3) inhibition, changes at the level of homeostatic synaptic plasticity, and regulation of microRNA expression as key mechanisms, providing an intriguing perspective that may help bridge the mechanistic gap between molecular functions and its clinical efficacy as a mood stabilizer.

A composite immune and vascular stress marker in patients newly diagnosed with bipolar disorder and their unaffected first-degree relatives

AIMS

Substantial evidence emphasizes immune dysregulation in patients with bipolar disorder (BD). However, whether immune dysregulation is present already in the early illness stages of BD or even precedes development of BD is largely unknown. In this study we compared immune and vascular stress markers in patients newly diagnosed with BD, their unaffected first-degree relatives (UR) and healthy control individuals (HC) and investigated the ability a composite immune and vascular stress marker to discriminate between the three groups of participants.

METHODS

In a unique sample including 373 patients newly diagnosed with BD, 95 UR and 190 HC, we compared 47 immune and vascular stress markers at the baseline visit in the ongoing longitudinal Bipolar Illness Onset study. For comparison of individual immune and vascular stress markers between groups, we applied linear mixed models, whereas the composite immune and vascular stress marker was investigated using the SuperLearner ensemble-method.

RESULTS

Compared with HC, patients newly diagnosed with BD had higher levels of the anti-inflammatory interleukin-1 receptor antagonist (IL-1RA) and IL-10, and of the pro-inflammatory IL-6, eotaxin, monocyte chemoattractant protein-1 (MCP-1), MCP-4, Macrophage Derived Chemokine (MDC), and Thymus and Activation-Regulated Chemokine (TARC) in analyses adjusted for sex and age ranging from 26 % higher levels of IL-6 (1.26, 95 %CI: [1.12-1.43], p < 0.001, adjusted p = 0.009) and IL-10 (1.26, 95 %CI: [1.09-1.46], p = 0.002, adjusted p = 0.049), respectively, to 9 % higher eotaxin levels (1.09, 95 %CI: [1.04-1.15], p = 0.001, adjusted p = 0.024). Of these, MDC levels were 12 % higher in BD compared with UR (1.12, 95 %CI: [1.02-1.22], p = 0.001, adjusted p = 0.024). For all other markers, UR showed no difference from patients with BD or HC. Based on a data-driven model, a composite marker including all 47 immune and vascular stress markers, sex, age, BMI, smoking status, and alcohol intake, discriminated patients with BD from HC with a with an area under the receiver operating curve (AUC) of 0.76 (95 % CI: 0.75-0.77) CONCLUSIONS: Higher levels of pro-inflammatory and anti-inflammatory immune markers are present in patients newly diagnosed with BD but not in UR compared with HC, supporting immune dysregulation playing a role in the pathophysiology of BD.

The relationship of neuropsychiatric symptoms with inflammatory markers in the hippocampus and cingulate cortex of bipolar disorder subjects: A post-mortem study

Increased levels of inflammation markers have been found in the peripheral tissue of individuals with bipolar disorder (BD), especially during mood episodes. Previous studies found distinctive inflammatory profiles across different brain regions, but potential associations with clinical symptoms are still lacking. This study aims to evaluate the association of neuropsychiatric symptoms with inflammatory markers in the hippocampus and cingulate of individuals with BD. Levels of IL-1β, IL-6, IL-17A, cortisol, and C-reactive protein (CRP) were measured in the hippocampus and anterior cingulate of 14 BD individuals and their non-psychiatric controls. Neuropsychiatric symptoms present in the three months before death were assessed using the Neuropsychiatric Inventory (NPI). In the BD group, greater NPI scores were associated with higher IL-6 in the hippocampus (p = 0.011) and cingulate (p = 0.038) and higher IL-1β (p = 0.039) in the hippocampus. After adjusting for age, sex and CDR, IL-1β and IL-6 were still associated with higher NPI in the hippocampus. In correlation analysis considering both BD and their controls, moderate positive associations were found between NPI and IL-6 and cortisol in the hippocampus (p < 0.001 and p = 0.006) and cingulate (p = 0.024 and p = 0.016), IL-1β (p < 0.001) and IL-17A in the hippocampus (p = 0.002). No difference in inflammatory markers was found according to type of psychotropic medication used. Hence, in individuals with BD, neuropsychiatric symptoms were differently associated with specific inflammatory cytokines and CRP in the hippocampus and cingulate. These results suggest that the neuroinflammatory changes occurring in BD may be more complex than previously expected and could be associated with clinical manifestations.

Plasma IGFBP-3 and IGFBP-5 levels are decreased during acute manic episodes in bipolar disorder patients

Introduction: Bipolar disorder (BD) is a recurrent and disabling psychiatric disorder related to low-grade peripheral inflammation and altered levels of the members of the insulin-like growth factor (IGF) family. The aim of this study was to evaluate the plasma levels of IGF-2, insulin-like growth factor-binding protein 1 (IGFBP-1), IGFBP-3, IGFBP-5, IGFBP-7, and inflammatory markers such as tumor necrosis factor α (TNF-α), monocyte chemoattractant protein 1 (MCP-1), and macrophage inflammatory protein 1β (MIP-1β). Methods: We used the Young Mania Rating Scale (YMRS) to determine the severity of the symptomatology, while proteins were measured by enzyme-linked immunosorbent assay (ELISA). We included 20 patients with BD who suffered a manic episode and 20 controls. Some BD patients (n = 10) were evaluated after a period (17 ± 8 days) of pharmacological treatment. Results: No statistical difference was found in IGF-2, IGFBP-1, IGFBP-7, TNF-α, and MIP-1β levels. However, IGFBP-3 and IGFBP-5 levels were found to be statistically decreased in BD patients. Conversely, the MCP-1 level was significantly increased in BD patients, but their levels were normalized after treatment. Intriguingly, only IGFBP-1 levels were significantly decreased after treatment. No significant correlation was found between the YMRS and any of the proteins studied either before or after treatment or between IGF proteins and inflammatory markers. Discussion: To some extent, IGFBP-3 and IGFBP-5 might be further explored as potential indicators of treatment responsiveness or diagnosis biomarkers in BD.

Abelson Helper Integration Site 1 haplotypes and peripheral blood expression associates with lithium response and immunomodulation in bipolar patients

RATIONALE

In bipolar disorder (BD), immunological factors play a role in the pathogenesis and treatment of the illness. Studies showed the potential link between Abelson Helper Integration Site 1 (AHI1) protein, behavioural changes and innate immunity regulation. An immunomodulatory effect was suggested for lithium, a mood stabilizer used in BD treatment.

OBJECTIVES

We hypothesized that AHI1 may be an important mediator of lithium treatment response. Our study aimed to investigate whether the AHI1 haplotypes and expression associates with lithium treatment response in BD patients. We also examined whether AHI1 expression and lithium treatment correlate with innate inflammatory response genes.

RESULTS

We genotyped seven AHI1 single nucleotide polymorphisms in 97 euthymic BD patients and found that TG haplotype (rs7739635, rs9494332) was significantly associated with lithium response. We also showed significantly increased AHI1 expression in the blood of lithium responders compared to non-responders and BD patients compared to healthy controls (HC). We analyzed the expression of genes involved in the innate immune response and inflammatory response regulation (TLR4, CASP4, CASP5, NLRP3, IL1A, IL1B, IL6, IL10, IL18) in 21 lithium-treated BD patients, 20 BD patients treated with other mood stabilizer and 19 HC. We found significantly altered expression between BD patients and HC, but not between BD patients treated with different mood stabilizers.

CONCLUSIONS

Our study suggests the involvement of AHI1 in the lithium mode of action. Moreover, mood-stabilizing treatment associated with the innate immunity-related gene expression in BD patients and only the lithium-treated BD patients showed significantly elevated expression of anti-inflammatory IL10, suggesting lithium's immunomodulatory potential.

The emerging neuroimmune hypothesis of bipolar disorder: An updated overview of neuroimmune and microglial findings

Bipolar disorder (BD) is a severe and multifactorial disease, with onset usually in young adulthood, which follows a progressive course throughout life. Replicated epidemiological studies have suggested inflammatory mechanisms and neuroimmune risk factors as primary contributors to the onset and development of BD. While not all patients display overt markers of inflammation, significant evidence suggests that aberrant immune signaling contributes to all stages of the disease and seems to be mood phase dependent, likely explaining the heterogeneity of findings observed in this population. As the brain's immune cells, microglia orchestrate the brain's immune response and play a critical role in maintaining the brain's health across the lifespan. Microglia are also highly sensitive to environmental changes and respond to physiological and pathological events by adapting their functions, structure, and molecular expression. Recently, it has been highlighted that instead of a single population of cells, microglia comprise a heterogeneous community with specialized states adjusted according to the local molecular cues and intercellular interactions. Early evidence has highlighted the contribution of microglia to BD neuropathology, notably for severe outcomes, such as suicidality. However, the roles and diversity of microglial states in this disease are still largely undermined. This review brings an updated overview of current literature on the contribution of neuroimmune risk factors for the onset and progression of BD, the most prominent neuroimmune abnormalities (including biomarker, neuroimaging, ex vivo studies) and the most recent findings of microglial involvement in BD neuropathology. Combining these different shreds of evidence, we aim to propose a unifying hypothesis for BD pathophysiology centered on neuroimmune abnormalities and microglia. Also, we highlight the urgent need to apply novel multi-system biology approaches to characterize the diversity of microglial states and functions involved in this enigmatic disorder, which can open bright perspectives for novel biomarkers and therapeutic discoveries.

Associations of altered leukocyte DDR1 promoter methylation and childhood trauma with bipolar disorder and suicidal behavior in euthymic patients

Altered DNA methylation (DNAm) patterns of discoidin domain receptor 1 (DDR1) have been found in the blood and brain of patients with schizophrenia (SCZ) and the brain of patients with bipolar disorder (BD). Childhood trauma (CT) is associated with changes in DNAm that in turn are related to suicidal behavior (SB) in patients with several psychiatric disorders. Here, using MassARRAY® technology, we studied 128 patients diagnosed with BD in remission and 141 healthy controls (HCs) to compare leukocyte DDR1 promoter DNAm patterns between patients and HCs and between patients with and without SB. Additionally, we investigated whether CT was associated with DDR1 DNAm and mediated SB. We found hypermethylation at DDR1 cg19215110 and cg23953820 sites and hypomethylation at cg14279856 and cg03270204 sites in patients with BD compared to HCs. Logistic regression models showed that hypermethylation of DDR1 cg23953820 but not cg19215110 and CT were risk factors for BD, while cg14279856 and cg03270204 hypomethylation were protective factors. In patients, CT was a risk factor for SB, but DDR1 DNAm, although associated with CT, did not mediate the association of CT with SB. This is the first study demonstrating altered leukocyte DDR1 promoter DNAm in euthymic patients with BD. We conclude that altered DDR1 DNAm may be related to immune and inflammatory mechanisms and could be a potential blood biomarker for the diagnosis and stratification of psychiatric patients.

New insights into the interaction between polycystic ovary syndrome and psychiatric disorders: A narrative review

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disease characterized by hyperandrogenism, ovulatory dysfunction, and ovarian polycystic changes, which combines with reproductive problems, metabolic disorders, and psychological disorders to exhibit a far-reaching impact on the physical and mental health of women. We reviewed previous research and discovered that psychiatric disorders are more common in PCOS patients and their children, potentially exacerbating the condition and creating a vicious loop. To understand the reasons, relevant articles were collected following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines from PubMed, Web of Science, and Cochrane Library, through December 2022. Evidence suggested that PCOS-related clinical manifestations, hyperandrogenism, insulin resistance, obesity, gut dysbiosis, and other variables may increase the risk of psychiatric disorders in patients. In turn, psychiatric disorders may aggravate the pathologic process of PCOS and increase the difficulty of the treatment. We systematically reported the mechanisms underlying the psychiatric disorders-PCOS interactions, intending to provide potential ways to break the vicious cycle and lay the groundwork for future research. However, research on PCOS and psychiatric disorders were still in initial stages, which limited the scope of this review. More studies are needed to further verify our findings.

Comparing the metabolic pathways of different clinical phases of bipolar disorder through metabolomics studies

This study identified the metabolic biomarkers for different clinical phases of bipolar disorder (BD) through metabolomics. BD patients were divided into three groups: patients with BD and depressive episodes (BE, n = 59), patients with BD and mania/hypomania episodes (BH, n = 16), patients with BD and mixed episodes (BM, n = 10), and healthy controls (HC, n = 10). Serum from participants was collected for metabolomic sequencing, biomarkers from each group were screened separately by partial least squares analysis, and metabolic pathways connected to the biomarkers were identified. Compared with the controls, 3-D-hydroxyacetic acid and N-acetyl-glycoprotein showed significant differences in the BE, BH, and BM groups. This study suggests that different clinical types of BD share the same metabolic pathways, such as pyruvate, glycolysis/gluconeogenesis, and ketone body metabolisms. In particular, abnormal glycine, serine, and threonine metabolism was specific to BM; β-glucose, glycerol, lipids, lactate, and acetoacetate metabolites were specific to depressive episodes; the guanidine acetic acid metabolites specific to BH; and the acetic and ascorbic acids were metabolites specific to manic and BM. We screened potential biomarkers for different clinical phases of BD, which aids in BD typing and provides a theoretical basis for exploring the molecular mechanisms of BD.

Inflammation and emotion regulation: a narrative review of evidence and mechanisms in emotion dysregulation disorders

Emotion dysregulation (ED) describes a difficulty with the modulation of which emotions are felt, as well as when and how these emotions are experienced or expressed. It is a focal overarching symptom in many severe and prevalent neuropsychiatric diseases, including bipolar disorders (BD), attention deficit/hyperactivity disorder (ADHD), and borderline personality disorder (BPD). In all these disorders, ED can manifest through symptoms of depression, anxiety, or affective lability. Considering the many symptomatic similarities between BD, ADHD, and BPD, a transdiagnostic approach is a promising lens of investigation. Mounting evidence supports the role of peripheral inflammatory markers and stress in the multifactorial aetiology and physiopathology of BD, ADHD, and BPD. Of note, neural circuits that regulate emotions appear particularly vulnerable to inflammatory insults and peripheral inflammation, which can impact the neuroimmune milieu of the central nervous system. Thus far, few studies have examined the link between ED and inflammation in BD, ADHD, and BPD. To our knowledge, no specific work has provided a critical comparison of the results from these disorders. To fill this gap in the literature, we review the known associations and mechanisms linking ED and inflammation in general, and clinically, in BD, ADHD, and BD. Our narrative review begins with an examination of the routes linking ED and inflammation, followed by a discussion of disorder-specific results accounting for methodological limitations and relevant confounding factors. Finally, we critically discuss both correspondences and discrepancies in the results and comment on potential vulnerability markers and promising therapeutic interventions.

High unrecognized SARS-CoV-2 exposure of newly admitted and hospitalized psychiatric patients

BACKGROUND

Patients with pre-existing mental disorders are at higher risk for SARS-CoV-2 infection and adverse outcomes, and severe mental illness, including mood and psychosis spectrum disorders, is associated with increased mortality risk. Despite their increased risk profile, patients with severe mental illness have been understudied during the pandemic, with limited estimates of exposure in inpatient settings.

OBJECTIVE

The aim of this study was to describe the SARS-CoV-2 seroprevalence and antibody titers, and pro-inflammatory cytokine concentrations of newly admitted or hospitalized psychiatric inpatients without known history of COVID-19 infection, using robust quantitative multi-antigen assessments, and compare patients' exposure to that of hospital staff.

METHODS

This multi-centric, cross-sectional study compared SARS-CoV-2 seroprevalence and titers of 285 patients (University Psychiatric Centre Duffel [UPCD] N = 194; Assistance-Publique-Hopitaux de Paris [AP-HP] N = 91), and 192 hospital caregivers (UPCD N = 130; AP-HP N = 62) at two large psychiatric care facilities between January 1st and the May 30th 2021. Serum levels of SARS-CoV-2 antibodies against Spike proteins (full length), spike subunit 1 (S1), spike subunit 2 (S2), spike subunit 1 receptor binding domain (S1-RBD) and Nucleocapsid proteins were quantitatively determined using an advanced capillary Western Blot technique. To assess the robustness of the between-group seroprevalence differences, we performed sensitivity analyses with stringent cut-offs for seropositivity. We also assessed peripheral concentrations of IL-6, IL-8 and TNF-a using ELLA assays. Secondary analyses included comparisons of SARS-CoV-2 seroprevalence and titers between patient diagnostic subgroups, and between newly admitted (hospitalization ≤ 7 days) and hospitalized patients (hospitalization > 7 days) and correlations between serological and cytokines.

RESULTS

Patients had a significantly higher SARS-CoV-2 seroprevalence (67.85 % [95% CI 62.20-73.02]) than hospital caregivers (27.08% [95% CI 21.29-33.77]), and had significantly higher global SARS-CoV-2 titers (F = 29.40, df = 2, p < 0.0001). Moreover, patients had a 2.51-fold (95% CI 1.95-3.20) higher SARS-CoV-2 exposure risk compared to hospital caregivers (Fisher's exact test, P < 0.0001). No difference was found in SARS-CoV-2 seroprevalence and titers between patient subgroups. Patients could be differentiated most accurately from hospital caregivers by their higher Spike protein titers (OR 136.54 [95% CI 43.08-481.98], P < 0.0001), lower S1 (OR 0.06 [95% CI 0.02-0.15], P < 0.0001) titers and higher IL-6 (OR 3.41 [95% CI 1.73-7.24], P < 0.0001) and TNF-α (OR 34.29 [95% CI 5.00-258.87], P < 0.0001) and lower titers of IL-8 (OR 0.13 [95% CI 0.05-0.30], P < 0.0001). Seropositive patients had significantly higher SARS-COV-2 antibody titers compared to seropositive hospital caregivers (F = 19.53, df = 2, P < 0.0001), while titers were not different in seronegative individuals. Pro-inflammatory cytokine concentrations were not associated with serological status.

CONCLUSION

Our work demonstrated a very high unrecognized exposure to SARS-CoV-2 among newly admitted and hospitalized psychiatric inpatients, which is cause for concern in the context of highly robust evidence of adverse outcomes following COVID-19 in psychiatric patients. Attention should be directed toward monitoring and mitigating exposure to infectious agents within psychiatric hospitals.

Elevated Brain-Derived Neurotrophic Factor Levels During Depressive Mixed States

OBJECTIVE

Neurotrophin-like brain-derived neurotrophic factor (BDNF) and pro-inflammatory cytokines may modulate the pathophysiology of mood disorders. Although several studies show alterations in these biomarkers during the depressive, manic, and euthymic states of mood disorders, evidence is lacking for those in a mixed state. Therefore, this study aimed to investigate the relationship between the depressive mixed state (DMX) and peripheral neurobiological factors.

METHODS

We enrolled 136 patients with major depressive episodes. Depressive symptoms were assessed using the Quick Inventory of Depressive Symptomatology Self-Report Japanese version (QIDS-SR-J). The severity of DMX was assessed using the self-administered 12-item questionnaire (DMX-12). Categorical screening as DMX-positive (n=54) was determined by a cutoff score of 13 or more in the specific eight symptoms from the DMX-12; the remaining were DMX-negative (n=82). Serum BDNF, tumor necrosis factor-α, highsensitivity C-reactive protein, and interleukin-6 levels were measured.

RESULTS

When comparing biomarkers between the DMX-positive and DMX-negative groups, higher serum BDNF concentration in the DMX-positive group than in the DMX-negative group was the only significant finding (p=0.009). A positive correlation existed between the total score of the eight specific symptoms of DMX-12 and the BDNF concentration (r=0.190, p=0.027). After adjustment for confounders, logistic regression analysis revealed that BDNF (odds ratio [OR]=1.07, 95% confidence interval [CI]=1.00-1.14, p=0.045), bipolar diagnosis (OR=3.43, 95% CI=1.36-8.66, p=0.009), and total QIDS-SR-J score (OR=1.29, 95% CI=1.15-1.43, p<0.001) were significantly associated with DMX positivity.

CONCLUSION

BDNF was positively associated with DMX severity, suggesting that higher BDNF concentrations may be involved in the pathophysiology of DMX.

Thiol-disulphide homeostasis, ischemia-modified albumin, complete blood count-derived inflammatory markers and C-reactive protein from acute mania to early remission in bipolar disorder

OBJECTIVES

There is much recent evidence that inflammation contributes to the pathophysiology of acute mania in bipolar disorder (BD). However, no study was evaluated in which the change in thiol-disulphide homeostasis, ischemia-modified albumin (IMA), complete blood count-derived inflammatory markers (CBC-IMs) and C-reactive protein (CRP) levels in bipolar patients was followed-up from acute mania to early remission.

METHODS

Seventy-seven bipolar patients in acute mania and ninety-one HC were enrolled. We measured levels of thiol-disulphide parameters, IMA, and CBC-IMs such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), red-cell-distribution-width (RDW)-to-platelet ratio (RPR), systemic immune-inflammatory index (SII), and systemic inflammatory response index (SIRI), CRP and platelet-to-albumin ratio (PAR), after adjusting for age, gender, body-mass index (BMI) and smoking status, during acute mania to subsequent early remission. The results were compared with HC.

RESULTS

The levels or ratios of all thiol-disulphide parameters except for disulphide, IMA and CRP of bipolar patients in both acute mania and early remission were significantly different from HC, after adjusting for confounders. The NLR, SII, CRP and PAR values of bipolar patients were significantly higher in only acute mania compared to HC. Significant changes in thiol-disulphide parameters and IMA levels were not found in early remission after acute mania.

LIMITATIONS

Short follow-up period and lack of drug-naive patients.

CONCLUSIONS

Our results suggest that thiol-disulphide parameters, IMA level and SIRI value might be a trait biomarkers of inflammation in BD. In addition, NLR, SII and PAR values and CRP level might be a state biomarker of inflammation in bipolar patients in a manic phase.

Neutrophil/high-density lipoprotein cholesterol (HDL), monocyte/HDL and platelet/HDL ratios are increased in acute mania as markers of inflammation, even after controlling for confounding factors

OBJECTIVE

Recent studies show that inflammation is related to the pathogenesis of acute mania of bipolar disorder. Neutrophil/high-density lipoprotein (HDL) ratio (NHR), lymphocyte/HDL ratio (LHR), monocyte/HDL ratio (MHR) and platelet/HDL ratio (PHR) have recently been investigated as novel markers of inflammation. In addition, the atherogenic index of plasma (AIP) and atherogenic coefficient (AC) are the leading atherogenic indices. The study aimed to investigate these inflammation and atherogenic index markers in acute mania of bipolar disorder. Another aim was to determine whether there is a relationship between these markers and disease severity and psychotic symptoms.

METHODS

A total of 109 BD-M and 101 (HC) were enrolled in the study. The differences in NHR, LHR, MHR, PHR, AIP and AC and their association with illness severity and psychotic symptoms were analyzed after adjusting for age, sex, total cholesterol level, body-mass index and smoking status. Then, a receiver operating characteristic (ROC) curve and linear discriminant analysis (LDA) were used to analyze these parameters' diagnostic potential. Moreover, the Young Mania Rating Scale (YMRS) and Clinical Global Impression Scale for use in bipolar illness-Severity subscale (CGI-BP-S) were used to assess the severity of clinical symptoms.

RESULTS

We found higher levels of NHR, MHR, PHR and AIP, but not LHR and AC, after adjusting confounding factors in patients with BD-M compared to HCs. In logistic regression analysis, higher levels of MHR and NHR were associated with BD-M. MHR, NHR and PHR were predictors for differentiating the BD-M group from the HC group. However, the severity of the illness or the psychotic feature of the manic episode did not significantly affect the parameters. In the ROC curve analysis of BD-M, the indicators with an area under the curve (AUC) higher than 0.6 were the MHR, NHR, PHR and LHR.

CONCLUSIONS

These results provide information about the role of inflammation in the pathophysiology of BD-M. Even after controlling for confounding factors, MHR, NHR, PHR and AIP are potential biomarkers for BD-M. Moreover, the increase in AIP may explain the co-morbidity between BD and cardiovascular diseases. However, the severity of the illness or the psychotic feature of the manic episode did not significantly affect the levels of inflammation ratios used in our study. Due to the low cost and widespread use of lipid metabolism and related inflammation rates, it may be beneficial to know the MHR, NHR, PHR and AIP levels in BD-M patients.

Inflammation associated with left ventricular hypertrophy in bipolar disorder: A cross-sectional study

OBJECTIVE

Inflammation has received increasing attention as a contributor to the pathophysiology of bipolar disorder (BD) and cardiac hypertrophy into heart failure (HF). Accordingly, we chose BD-related inflammatory markers to investigate their relationships with cardiac left ventricular function and structure in BD.

METHODS

Sixty physically healthy and euthymic patients with bipolar I disorder were recruited to compare with 50 healthy normal controls. The echocardiography was performed to estimate left ventricular mass index (LVMI) as a parameter of LV hypertrophy (LVH) and left ventricle ejection fraction (LVEF) as a parameter of systolic function. An LVEF above the normal range (>70%) was defined as a hyperdynamic heart. Participants' levels of inflammatory and atherosclerosis-related parameters were measured.

RESULTS

Compared with normal controls, BD group had significantly higher rates of LVH (63% vs. 42%) and hyperdynamic heart (32% vs. 2%) and higher mean values of LVMI and LVEF. After adjustment for the effects of BMI and age, multiple regression analyses of BD group showed that the peripheral level of interleukin-8 was positively associated with LVMI and the level of soluble tumor necrosis factor receptor 1 (sTNF-R1) was positively associated with LVEF.

CONCLUSIONS

Patients with BD from young adulthood are likely to have LVH with normal LV function and hyperdynamic heart associated with diastolic dysfunction. Low-grade inflammation may underlie the mechanisms of LV hypertrophy and cardiac dysfunction in BD patients.

Non-canonical pathways in the pathophysiology and therapeutics of bipolar disorder

Bipolar disorder (BD) is characterized by extreme mood swings ranging from manic/hypomanic to depressive episodes. The severity, duration, and frequency of these episodes can vary widely between individuals, significantly impacting quality of life. Individuals with BD spend almost half their lives experiencing mood symptoms, especially depression, as well as associated clinical dimensions such as anhedonia, fatigue, suicidality, anxiety, and neurovegetative symptoms. Persistent mood symptoms have been associated with premature mortality, accelerated aging, and elevated prevalence of treatment-resistant depression. Recent efforts have expanded our understanding of the neurobiology of BD and the downstream targets that may help track clinical outcomes and drug development. However, as a polygenic disorder, the neurobiology of BD is complex and involves biological changes in several organelles and downstream targets (pre-, post-, and extra-synaptic), including mitochondrial dysfunction, oxidative stress, altered monoaminergic and glutamatergic systems, lower neurotrophic factor levels, and changes in immune-inflammatory systems. The field has thus moved toward identifying more precise neurobiological targets that, in turn, may help develop personalized approaches and more reliable biomarkers for treatment prediction. Diverse pharmacological and non-pharmacological approaches targeting neurobiological pathways other than neurotransmission have also been tested in mood disorders. This article reviews different neurobiological targets and pathophysiological findings in non-canonical pathways in BD that may offer opportunities to support drug development and identify new, clinically relevant biological mechanisms. These include: neuroinflammation; mitochondrial function; calcium channels; oxidative stress; the glycogen synthase kinase-3 (GSK3) pathway; protein kinase C (PKC); brain-derived neurotrophic factor (BDNF); histone deacetylase (HDAC); and the purinergic signaling pathway.

Metabolic regulation to treat bipolar depression: mechanisms and targeting by trimetazidine

Bipolar disorder's core feature is the pathological disturbances in mood, often accompanied by disrupted thinking and behavior. Its complex and heterogeneous etiology implies that a range of inherited and environmental factors are involved. This heterogeneity and poorly understood neurobiology pose significant challenges to existing drug development paradigms, resulting in scarce treatment options, especially for bipolar depression. Therefore, novel approaches are needed to discover new treatment options. In this review, we first highlight the main molecular mechanisms known to be associated with bipolar depression-mitochondrial dysfunction, inflammation and oxidative stress. We then examine the available literature for the effects of trimetazidine in said alterations. Trimetazidine was identified without a priori hypothesis using a gene-expression signature for the effects of a combination of drugs used to treat bipolar disorder and screening a library of off-patent drugs in cultured human neuronal-like cells. Trimetazidine is used to treat angina pectoris for its cytoprotective and metabolic effects (improved glucose utilization for energy production). The preclinical and clinical literature strongly support trimetazidine's potential to treat bipolar depression, having anti-inflammatory and antioxidant properties while normalizing mitochondrial function only when it is compromised. Further, trimetazidine's demonstrated safety and tolerability provide a strong rationale for clinical trials to test its efficacy to treat bipolar depression that could fast-track its repurposing to address such an unmet need as bipolar depression.

Hormonal and inflammatory signatures of different mood episodes in bipolar disorder: a large-scale clinical study

BACKGROUND

Bipolar disorder (BD) is characterized by intensive mood fluctuations. While hormones imbalance plays important role in the mood swings, it is unknown whether peripheral hormones profiles could differentiate the manic and depressive mood episodes in BD. In this study, we investigated the changes of various hormones and inflammatory markers across distinct mood episodes of BD in a large clinical study to provide mood episode-specific peripheral biomarkers for BD.

METHODS

A total of 8332 BD patients (n = 2679 depressive episode; n = 5653 manic episode) were included. All patients were in acute state of mood episodes and need hospitalization. A panel of blood tests were performed for levels of sex hormones (serum levels of testosterone, estradiol, and progesterone), stress hormones (adrenocorticotropic hormone and cortisol), and an inflammation marker (C-reactive protein, CRP). A receiver operating characteristic (ROC) curve was used to analyze the discriminatory potential of the biomarkers for mood episodes.

RESULTS

In overall comparison between mood episodes, the BD patients expressed higher levels of testosterone, estradiol, progesterone, and CRP (P < 0.001) and lower adrenocorticotropic hormone (ACTH) level (P < 0.001) during manic episode. The episode-specific changes of testosterone, ACTH, and CRP levels remained between the two groups (P < 0.001) after correction for the confounding factors including age, sex, BMI, occupation, marital status, tobacco use, alcohol consumption, psychotic symptoms, and age at onset. Furthermore, we found a sex- and age-specific impact of combined biomarkers in mood episodes in male BD patients aged ≥ 45 years (AUC = 0.70, 95% CI, 0.634-0.747), not in females.

CONCLUSIONS

While both hormone and inflammatory change is independently associated with mood episodes, we found that the combination of sex hormones, stress hormones and CRP could be more effective to differentiate the manic and depressive episode. The biological signatures of mood episodes in BD patients may be sex- and age-specific. Our findings not only provide mood episode-related biological markers, but also better support for targeted intervention in BD treatments.

Age-related modifications in CYP-dependent drug metabolism: role of stress

Accumulating clinical evidence indicates extensive inter-individual variations in the effectiveness and adverse effects of standard treatment protocols, which are largely attributed to the multifactorial regulation of the hepatic CYP-dependent drug metabolism that is connected with either transcriptional or post-translational modifications. Age and stress belong to the most important factors in CYP gene regulation. Alterations in neuroendocrine responses to stress, which are associated with modified hypothalamo-pituitary-adrenal axis function, usually accompany ageing. In this light, ageing followed by a decline of the functional integrity of organs, including liver, a failure in preserving homeostasis under stress, increased morbidity and susceptibility to stress, among others, holds a determinant role in the CYP-catalyzed drug metabolism and thus, in the outcome and toxicity of pharmacotherapy. Modifications in the drug metabolizing capacity of the liver with age have been reported and in particular, a decline in the activity of the main CYP isoforms in male senescent rats, indicating decreased metabolism and higher levels of the drug-substrates in their blood. These factors along with the restricted experience in the use of the most medicines in childhood and elderly, could explain at an extent the inter-individual variability in drug efficacy and toxicity outcomes, and underscore the necessity of designing the treatment protocols, accordingly.

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.

Ferritin as a potential disease marker in patients with bipolar disorder

BACKGROUND

Low-grade inflammation and oxidative stress have been implicated as potential pathophysiological processes in bipolar disorder, but the underlying mechanism is unknown. Ferritin is a marker of iron stores and involved in redox processes and inflammation but its role in bipolar disorder is unclear.

METHODS

We investigated the possible association of increased plasma ferritin levels and bipolar disorder. We pooled two studies using similar longitudinal repeated measures designs and included 330 blood- and urinary samples from 95 patients with bipolar disorder across all affective states and 84 samples from 84 healthy control individuals. Plasma ferritin was measured along with multiple blood inflammatory markers and urinary markers of oxidatively generated damage to DNA and RNA.

RESULTS

Plasma ferritin levels, adjusting for multiple demographical- and lifestyle variables, did not differ between patients with bipolar disorder compared with healthy control individuals (b = 1.09, 95 % CI: 0.86 to 1.39, p = 0.49). Within patients with bipolar disorder ferritin levels were higher in a depressed state compared with euthymia (b = 1.12, 95 % CI: 1.01 to 1.24, p < 0.04), and ferritin levels were positively associated with Interleukin-18 blood levels and urinary levels of 8-oxodG.

LIMITATIONS

Patients with bipolar disorder received medication which could potentially influence iron metabolism.

CONCLUSION

Elevated ferritin levels in depressed patients with bipolar disorder may point to a role for iron metabolism in bipolar disorder pathophysiology, and potentially as a biomarker, linking low-grade inflammation with redox biology and the well-known increased risk of medical comorbidity and reduced life expectancy.

Mood Disorders in Youth: Complementary and Integrative Medicine

Omega-3 polyunsaturated fatty acids, probiotics, vitamin C, vitamin D, folic acid and L-methyl folate, broad-spectrum micronutrients, N-acetylcysteine, physical activity, herbs, bright light therapy, melatonin, saffron, meditation, school-based interventions, and transcranial photobiomodulation are reviewed, with a focus on their use for treating mood disorders in children and adolescents. For each treatment, all published randomized controlled trials are summarized.

Impact of data extraction errors in meta-analyses on the association between depression and peripheral inflammatory biomarkers: an umbrella review

BACKGROUND

Accumulating evidence suggests that alterations in inflammatory biomarkers are important in depression. However, previous meta-analyses disagree on these associations, and errors in data extraction may account for these discrepancies.

METHODS

PubMed/MEDLINE, Embase, PsycINFO, and the Cochrane Library were searched from database inception to 14 January 2020. Meta-analyses of observational studies examining the association between depression and levels of tumor necrosis factor-α (TNF-α), interleukin 1-β (IL-1β), interleukin-6 (IL-6), and C-reactive protein (CRP) were eligible. Errors were classified as follows: incorrect sample sizes, incorrectly used standard deviation, incorrect participant inclusion, calculation error, or analysis with insufficient data. We determined their impact on the results after correction thereof.

RESULTS

Errors were noted in 14 of the 15 meta-analyses included. Across 521 primary studies, 118 (22.6%) showed the following errors: incorrect sample sizes (20 studies, 16.9%), incorrect use of standard deviation (35 studies, 29.7%), incorrect participant inclusion (7 studies, 5.9%), calculation errors (33 studies, 28.0%), and analysis with insufficient data (23 studies, 19.5%). After correcting these errors, 11 (29.7%) out of 37 pooled effect sizes changed by a magnitude of more than 0.1, ranging from 0.11 to 1.15. The updated meta-analyses showed that elevated levels of TNF- α, IL-6, CRP, but not IL-1β, are associated with depression.

CONCLUSIONS

These findings show that data extraction errors in meta-analyses can impact findings. Efforts to reduce such errors are important in studies of the association between depression and peripheral inflammatory biomarkers, for which high heterogeneity and conflicting results have been continuously reported.

Structural and functional MRI correlates of inflammation in bipolar disorder: A systematic review

BACKGROUND

Bipolar disorder (BD) is a common affective disorder characterized by recurrent oscillations between mood states and associated with inflammatory diseases and chronic inflammation. However, data on MRI abnormalities in BD and their relationship with inflammation are heterogeneous and no review has recapitulated them.

METHODS

In this pre-registered (PROSPERO: CRD42022308461) systematic review we searched Web of Science Core Collection and PubMed for articles correlating functional or structural MRI measures with immune-related markers in BD.

RESULTS

We included 23 studies (6 on functional, 16 on structural MRI findings, 1 on both, including 1'233 BD patients). Overall, the quality of the studies included was fair, with a low risk of bias.

LIMITATIONS

Heterogeneity in the methods and results of the studies and small sample sizes limit the generalizability of the conclusions.

CONCLUSIONS

A qualitative synthesis suggests that the links between immune traits and functional or structural MRI alterations point toward brain areas involved in affective and somatomotor processing, with a trend toward a negative correlation between peripheral inflammatory markers and brain regions volume. We discuss how disentangling the complex relationship between the immune system and MRI alterations in BD may unveil mechanisms underlying symptoms pathophysiology, potentially with quickly translatable diagnostic, prognostic, and therapeutic implications.

Biomarkers of neuroprogression and late staging in bipolar disorder: A systematic review

BACKGROUND

Bipolar disorder may undertake a progressive course in a subset of patients, and research efforts have been made to understand the biological basis underlying this process. This systematic review examined the literature available on biological markers associated with illness progression in bipolar disorder.

METHODS

Peer-reviewed articles were assessed using Embase, PsycINFO and PubMed, as well as from external sources. After initial screening, a total of 871 citations from databases and other sources were identified. Participants with a diagnosis of bipolar disorder were included in our systematic review; however, studies with participants younger than 15 or older than 65 were excluded. All studies were assessed using the Newcastle-Ottawa Scale assessment tool, and data pertaining to the results were extracted into tabular form using Google Sheets and Google Documents. The systematic review was registered on PROSPERO international prospective register of systematic reviews (ID Number: CRD42020154305).

RESULTS

A total of 35 studies were included in the systematic review. Increased ventricular size and reduction of grey matter volume were the most common brain changes associated with illness progression in bipolar disorder. Among the several biomarkers evaluated in this systematic review, findings also indicate a role of peripheral inflammatory markers in this process.

DISCUSSION

The studies evaluating the biological basis of the illness progression in bipolar disorder are still scarce and heterogeneous. However, current evidence supports the notion of neuroprogression, the pathophysiological process related to progressive brain changes associated with clinical progression in patients with bipolar disorder. The increase in peripheral inflammatory biomarkers and the neuroanatomical changes in bipolar disorder suggest progressive systemic and structural brain alterations, respectively.

Suicide in bipolar disorder patients is associated with hippocampal microglia activation and reduction of lymphocytes-activation gene 3 (LAG3) microglial checkpoint expression

BACKGROUND

Bipolar disorder (BD) is associated with marked functional impairments along with increased rate of suicide. Although there is ample evidence for the involvement of inflammatory processes and microglia activation in the pathophysiology of BD, the mechanisms that regulate these cells in BD patients, and particularly the role of microglia checkpoints, is still unclear.

METHODS

Immunohistochemical analyses of hippocampal sections from post-mortem brains of 15 BD patients and 12 control subjects were used to assess microglia density, by staining the microglia-specific receptor P2RY12, and microglia activation, by staining the activation marker MHC II. Given recent findings on the involvement of LAG3, which interacts with MHC II and serves as a negative microglia checkpoint, in depression and electroconvulsive therapy, we assessed the levels of LAG3 expression and their correlations with microglia density and activation.

RESULTS

There were no overall differences between BD patients and controls, but BD patients who committed suicide (N = 9) displayed a significant elevation in the overall microglia density and the density of MHC II-labeled microglia (but not other MHC II-labeled cells), compared with no suicide BD patients (N = 6) and controls. Furthermore, the percent of microglia expressing LAG3 was significantly reduced only in suicidal BD patients, with significant negative correlations between microglial LAG3 expression levels and the density of microglia, in general, and activated microglia, in particular.

CONCLUSION

Suicidal BD patients exhibit microglia activation, which is possibly mediated by reduced LAG3 checkpoint expression, suggesting that anti-microglial therapeutics, including LAG3 modulators, may be beneficial for this subgroup of patients.

Association between inflammatory cytokines and symptoms of major depressive disorder in adults

Objective

This study investigated the association between inflammatory cytokines and major depressive disorder.

Methods

Plasma biomarkers were measured by enzyme-linked immunosorbent assay (ELISA). Statistical analysis of baseline biomarkers in the major depression disorder (MDD) group and healthy controls (HC) group, and differences in biomarkers before and after treatment. Spearman analysis was performed to correlate baseline and after treatment MDD biomarkers with the 17-item Hamilton Depression Rating Scale (HAMD-17) total scores. Receiver operator characteristic (ROC) curves were analyzed for the effect of biomarkers on MDD and HC classification and diagnosis.

Results

Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were significantly higher in the MDD group than in the HC group, while high mobility group protein 1 (HMGB1) levels were significantly lower in the MDD group. The AUCs for HMGB1, TNF-α, and IL-6 were 0.375, 0.733, and 0.783, respectively, according to the ROC curves. MDD patients with brain-derived neurotrophic factor precursor (proBDNF) levels were positively correlated with total HAMD-17 scores. The levels of proBDNF levels were positively correlated with the total HAMD-17 score in male MDD patients, and brain-derived neurotrophic factor (BDNF) and interleukin 18 (IL-18) levels were negatively correlated with the total HAMD-17 score in female MDD patients.

Conclusion

Inflammatory cytokines are associated with the severity of MDD, and TNF-α and IL-6 have the potential as objective biomarkers to aid in the diagnosis of MDD.

Biomarkers in the Rat Hippocampus and Peripheral Blood for an Early Stage of Mental Disorders Induced by Water Immersion Stress

It is difficult to evaluate the pre-symptomatic state of mental disorders and prevent its onset. Since stress could be a trigger of mental disorders, it may be helpful to identify stress-responsive biomarkers (stress markers) for the evaluation of stress levels. We have so far performed omics analyses of the rat brain and peripheral blood after various kinds of stress and have found numerous factors that respond to stress. In this study, we investigated the effects of relatively moderate stress on these factors in the rat to identify stress marker candidates. Adult male Wistar rats underwent water immersion stress for 12 h, 24 h, or 48 h. Stress caused weight loss and elevated serum corticosterone levels, and alterations regarded as anxiety and/or fear-like behaviors. Reverse-transcription PCR and Western blot analyses revealed significant alterations in the expressions of hippocampal genes and proteins by the stress for no longer than 24 h, such as mitogen-activated protein kinase phosphatase 1 (MKP-1), CCAAT/enhancer-binding protein delta (CEBPD), small ubiquitin-like modifier proteins 1/sentrin-specific peptidase 5 (SENP5), matrix metalloproteinase-8 (MMP-8), kinase suppressor of Ras 1 (KSR1), and MKP-1, MMP-8, nerve growth factor receptor (NGFR). Similar alterations were observed in three genes (MKP-1, CEBPD, MMP-8) in the peripheral blood. The present results strongly suggest that these factors may serve as stress markers. The correlation of these factors in the blood and brain may enable the evaluation of stress-induced changes in the brain by blood analysis, which will contribute to preventing the onset of mental disorders.

Associations of white blood cell and platelet counts with specific depressive symptom dimensions in patients with bipolar disorder: Analysis of data from the FACE-BD cohort

Evidences suggest that inflammation is increased in a subgroup of patients with depression. Moreover, increased peripheral inflammatory markers (cells and proteins) are associated with some, but not all depressive symptoms. On the other hand, similar studies on bipolar disorders mainly focused on blood cytokines. Here, we analysed data from a large (N = 3440), well-characterized cohort of individuals with bipolar disorder using Kendall partial rank correlation, multivariate linear regression, and network analyses to determine whether peripheral blood cell counts are associated with depression severity, its symptoms, and dimensions. Based on the self-reported 16-Item Quick Inventory of Depressive Symptomatology questionnaire scores, we preselected symptom dimensions based on literature and data-driven principal component analysis. We found that the counts of all blood cell types were only marginally associated with depression severity. Conversely, white blood cell count was significantly associated with the sickness dimension and its four components (anhedonia, slowing down, fatigue, and appetite loss). Platelet count was associated with the insomnia/restlessness dimension and its components (initial, middle, late insomnia and restlessness). Principal component analyses corroborated these results. Platelet count was also associated with suicidal ideation. In analyses stratified by sex, the white blood cell count-sickness dimension association remained significant only in men, and the platelet count-insomnia/restlessness dimension association only in women. Without implying causation, these results suggest that peripheral blood cell counts might be associated with different depressive symptoms in individuals with bipolar disorder, and that white blood cells might be implicated in sickness symptoms and platelets in insomnia/agitation and suicidal ideation.

Nutrient combinations exhibit universal antianxiety, antioxidant, neuro-protecting, and memory-improving activities

Anxiety disorders are the most common mental disorders and, without proper treatment, may lead to severe conditions: e.g., somatic disorders or permanent damage to central nervous system. Although there are drugs in clinical trials, this study focuses on exploring the efficacy of nutrients in treating these diseases. We built different zebrafish models and screened several nutrient combinations for their antianxiety, antioxidant, neuro-protecting, and memory-improving activities. Our results showed that the combinations of nutrients (e.g., Walnut Peptides + Theanine at 14.2 + 33.3 μg/ml) have similar or better activities than the positive control drugs. In addition, we discovered that the effects of the nutrients in the above four aspects were universal and highly related. This study is noteworthy as it suggested that nutrients could be healthier and greener drug alternatives and provide similar or better universal treatments for anxiety and related conditions.

Reduced Cortical Thicknesses of Adolescents with Bipolar Disorder and Relationship with Brain-derived Neurotrophic Factor

Background

Cortical thickness (CT) and brain-derived neurotrophic factor (BDNF) were widely investigated in bipolar disorder (BD). Previous studies focused on the association between the volume of subcortical regions and neurotrophic factor levels.

Objective

In this study, we aimed to evaluate the association of the CT in youth with early-onset BD with BDNF levels as a potential peripheral marker of neuronal integrity.

Method

Twenty-three euthymic patients having a clinical diagnosis of BD and 17 healthy subjects as an age-matched control group with neuroimaging and blood BDNF levels were found eligible for CT measurement. A structural magnetic resonance scan (MRI) and timely blood samples were drawn.

Results

Youth with BD exhibited lower cortical thickness in caudal part of left (L) middle frontal gyrus, right (R) paracentral gyrus, triangular part of R inferior frontal gyrus, R pericalcarine region, R precentral gyrus, L precentral gyrus, R superior frontal gyrus and L superior frontal gyrus when compared to healthy controls. The effect sizes of these differences were moderate to large (d=0.67-0.98) There was a significant correlation between BDNF levels with caudal part of the R anterior cingulate gyrus (CPRACG) in adolescents with BD (r=0.49, p=0.023).

Conclusion

As a special region for mood regulation, the CT of the caudal part of the R anterior cingulate gyrus had a positive correlation with BDNF. Regarding the key role of CPRACG for affective regulation skills, our results should be replicated in future follow-up studies, investigating a predictive neuroimaging biomarker for the early-onset BD.

A longitudinal study of the association between pro-inflammatory cytokines and mood symptoms in bipolar disorder

BACKGROUND

Because of a relative dearth of longitudinal studies, the directionality of the relationship between mood and inflammation among patients with bipolar disorder (BD) is still unclear. We aimed to investigate the longitudinal associations of pro-inflammatory markers with mood symptom severity in BD.

METHODS

Hundred and thirty-two adult patients with BD were enrolled. At the baseline and 1-year follow-up visit, all participants received mood assessment with Montgomery Åsberg depression rating scale (MADRS) and Young mania rating scale, and underwent blood draws to quantify metabolic profile and serum levels of the pro-inflammatory markers, including soluble interleukin-6 receptor, soluble tumor necrosis factor-α receptor type 1 (sTNF-αR1), monocyte chemoattractant protein-1, and C-reactive protein. A four-factor model of MADRS, consisting of sadness, negative thoughts, detachment, and neurovegetative symptoms, were applied.

RESULTS

At baseline, 65 patients with BD were in depressed state, and 67 patients with BD were in euthymic state. Among patients in depressed state, baseline MADRS total score positively correlated with sTNF-αR1 level at follow-up. While baseline sTNF-αR1 level positively predicted sadness symptom in euthymic patients with BD who later developed depression (n = 22), sadness in patients with bipolar depression predicted later increase in serum sTNF-αR1 level even after remission (n = 17). Moreover, lithium had a stronger effect of lowering peripheral sTNF-αR1 level as compared with other mood stabilizers.

CONCLUSION

Our results indicate the bidirectional inflammation-depression relationship in BD.

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.

Clinical Utility of Fluid Biomarker in Depressive Disorder

Major depressive disorders are ranked as the single largest contributor to non-fatal health loss and biomarkers could largely improve our routine clinical activity by predicting disease course and guiding treatment. However there is still a dearth of valid biomarkers in the field of psychiatry. The initial assumption that a single biomarker can capture the myriad of complex processes proved to be naive. The purpose of this paper is to critically review the field and to illustrate the possible practical application for routine clinical care. Biomarkers derived from DNA analysis are the ones that have received the most attention. Other potential candidates include circulating transcription products, proteins, and inflammatory markers. DNA polygenic risk scores proved to be useful in other fields of medicine and preliminary results suggest that they could be useful both as risk and diagnostic biomarkers also in depression and for the choice of treatment. A number of other possible fluid biomarkers are currently under investigation for diagnosis, outcome prediction, staging, and stratification of interventions, however research is still needed before they can be used for routine clinical care. When available, clinicians may be able to receive a lab report with detailed information about disease risk, outcome prediction, and specific indications about preferred treatments.

An integrated cytokine and kynurenine network as the basis of neuroimmune communication

Two of the molecular families closely associated with mediating communication between the brain and immune system are cytokines and the kynurenine metabolites of tryptophan. Both groups regulate neuron and glial activity in the central nervous system (CNS) and leukocyte function in the immune system, although neither group alone completely explains neuroimmune function, disease occurrence or severity. This essay suggests that the two families perform complementary functions generating an integrated network. The kynurenine pathway determines overall neuronal excitability and plasticity by modulating glutamate receptors and GPR35 activity across the CNS, and regulates general features of immune cell status, surveillance and tolerance which often involves the Aryl Hydrocarbon Receptor (AHR). Equally, cytokines and chemokines define and regulate specific populations of neurons, glia or immune system leukocytes, generating more specific responses within restricted CNS regions or leukocyte populations. In addition, as there is a much larger variety of these compounds, their homing properties enable the superimposition of dynamic variations of cell activity upon local, spatially limited, cell populations. This would in principle allow the targeting of potential treatments to restricted regions of the CNS. The proposed synergistic interface of 'tonic' kynurenine pathway affecting baseline activity and the superimposed 'phasic' cytokine system would constitute an integrated network explaining some features of neuroimmune communication. The concept would broaden the scope for the development of new treatments for disorders involving both the CNS and immune systems, with safer and more effective agents targeted to specific CNS regions.

The Role of Equilibrium between Free Radicals and Antioxidants in Depression and Bipolar Disorder

Background: Increasing evidence suggests that the presence of oxidative stress and disorders of the antioxidant defense system are involved in a wide range of neuropsychiatric disorders, such as bipolar disorder, schizophrenia and major depression, but the exact mechanism remains unknown. This review focuses on a better appreciation of the contribution of oxidative stress to depression and bipolar disorder. Methods: This review was conducted by extracting information from other research and review studies, as well as other meta-analyses, using two search engines, PubMed and Google Scholar. Results: As far as depression is concerned, there is agreement among researchers on the association between oxidative stress and antioxidants. In bipolar disorder, however, most of them observe strong lipid peroxidation in patients, while regarding antioxidant levels, opinions are divided. Nevertheless, in recent years, it seems that on depression, there are mainly meta-analyses and reviews, rather than research studies, unlike on bipolar disorder. Conclusions: Undoubtedly, this review shows that there is an association among oxidative stress, free radicals and antioxidants in both mental disorders, but further research should be performed on the exact role of oxidative stress in the pathophysiology of these diseases.

Neuroinflammation and neuroprogression produced by oxidative stress in euthymic bipolar patients with different onset disease times

Bipolar disorder (BD) is associated with systemic toxicity, represented by changes in biomarkers associated with mood episodes, leading to neurological damage, which may reflect cognitive functions and functionality and the progression of the disease. We aimed to analyze the effect of four biomarkers, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBA-RS), related to oxidative stress in BD and to correlate them with cognitive functions and functionality. We studied 50 bipolar types I/II patients in the euthymic phase, which was divided into two subgroups with 25 patients each (≤ 3 years and ≥ 10 years of diagnosis, from the first episode of mania) and 25 control patients. To analyze frontal cognitive functions and functionality, we used the Frontal Assessment Battery (FAB) and Functioning Assessment Short Test (FAST) tests, respectively. The scores of the FAST and FAB tests showed an increase and decrease respectively, in both bipolar groups, when compared to the control group, demonstrating impairment in cognitive functions and functionality since the disease onset. In addition, changes occurred in all six domains of the FAST test, and in four domains of the FAB test in bipolar patients when compared to the control group. Regarding oxidative stress biomarkers, we did not find changes in SOD and GSH-Px activities; however, a significant increase in CAT activity and lipid peroxidation was observed in both groups, although the patients were euthymic and medicated. These results allow us to raise the hypothesis that since the beginning of the disease, the euthymic bipolar patient has presented a level of oxidative stress, which gets worse with the evolution of the disease, promoting impairments in the frontal cognitive functions and functionality gradually.

Störungsspezifische und transdiagnostische Veränderung der Inflammationsaktivität bei psychischen Störungen

Zusammenfassung. Theoretischer Hintergrund: Empirische Befunde deuten vermehrt auf eine erhöhte Entzündungsaktivität im Zusammenhang mit psychischen Störungen hin. Inwieweit sich inflammatorische Veränderungen über Störungen hinweg unterscheiden bzw. ob Inflammation ein transdiagnostisches Korrelat psychischer Störungen darstellt, ist bisher jedoch noch nicht eindeutig beantwortet. Fragestellung: Liegen spezifische inflammatorische Marker (z. B. Zytokine) über psychische Störungen hinweg verändert vor und/oder gibt es störungsspezifische Zytokinveränderungen bei Major Depression (MDD), Bipolarer Störung, Schizophrenie und Angststörungen inkl. Posttraumatischer Belastungsstörung (PTBS). Methode: Basierend auf einer Literaturrecherche werden aktuelle metaanalytische Befunde, die Studien bei Patient_innen mit MDD, Bipolarer Störung, Schizophrenie oder Angststörungen inkl. PTBS im Vergleich zu gesunden Kontrollen betrachten, zusammengetragen und vergleichend dargestellt. Ergebnisse: Aktuelle Evidenz verweist relativ konsistent auf Veränderungen des Immunsystems, wobei v. a. das Zytokin Interleukin (IL–) 6 und das C-reaktive Protein (CRP) störungsübergreifend leicht erhöht sind. Schlussfolgerungen: Perspektivisch könnten Patient_innen mit chronisch inflammatorischen Erkrankungen und psychischen Störungen von psychotherapiebegleitenden antiinflammatorischen Maßnahmen wie bspw. körperlicher Aktivität, antiinflammatorischer Ernährung und Entspannungsverfahren profitieren.

Long-term effect of childhood trauma: Role of inflammation and white matter in mood disorders

Bipolar disorder (BD) and major depressive disorder (MDD) are severe psychiatric illnesses that share among their environmental risk factors the exposure to adverse childhood experiences (ACE). Exposure to ACE has been associated with long-term changes in brain structure and the immune response. In the lasts decades, brain abnormalities including alterations of white matter (WM) microstructure and higher levels of peripheral immune/inflammatory markers have been reported in BD and MDD and an association between inflammation and WM microstructure has been shown. However, differences in these measures have been reported by comparing the two diagnostic groups. The aim of the present study was to investigate the interplay between ACE, inflammation, and WM in BD and MDD. We hypothesize that inflammation will mediate the association between ACE and WM and that this will be different in the two groups. A sample of 200 patients (100 BD, 100 MDD) underwent 3T MRI scan and ACE assessment through Childhood Trauma Questionnaire. A subgroup of 130 patients (75 MDD and 55 BD) underwent blood sampling for the assessment of immune/inflammatory markers. We observed that ACE associated with higher peripheral levels of IL-2, IL-17, bFGF, IFN-γ, TNF-α, CCL3, CCL4, CCL5, and PDGF-BB only in the BD group. Further, higher levels of CCL3 and IL-2 associated with lower FA in BD. ACE were found to differently affect WM microstructure in the two diagnostic groups and to be negatively associated with FA and AD in BD patients. Mediation analyses showed a significant indirect effect of ACE on WM microstructure mediated by IL-2. Our findings suggest that inflammation may mediate the detrimental effect of early experiences on brain structure and different mechanisms underlying brain alterations in BD and MDD.

Predictive value of oxidative stress biomarkers in drug-free patients with bipolar disorder

OBJECTIVE

Oxidative stress is one of the primary etiological mechanisms of bipolar disorder (BD).

METHODS

The present study was conducted over a period of 24 months on Tunisian on 34 drug‑free male patients with BD (mean age: 34.5 years) and 101 age and gender matched controls (mean age: 34.20 years) were enrolled in the study.

RESULTS

Plasma reduced glutathione (GSH) and total thiols levels were significantly decreased in patients compared to controls (respectively p < .001; p = .009). In addition, malondialdehyde (MDA), advanced oxidation protein products (AOPP), protein carbonyls (PC) and homocysteine (Hcys) concentrations and glutathione peroxidase (GSH-Px) activity were significantly increased in patients compared to controls (p = .002; p < .001; p = .001; p < .001 and p = .016, respectively). The binary logistic regression analysis revealed that MDA, AOPP and Hcys could be considered as independent risk factors for BD. When using CombiROC analysis, a remarkable increase in the area under the curve (AUC) with higher sensitivity (Se) and specificity (Sp) for MDA, AOPP, PC, GSH-Px and Hcys combined markers was observed.

CONCLUSIONS

Overall, the identification of the predictive value of these five selected biomarkers related to oxidative stress in drug free patients should lead to a better identification of the etiological mechanism of BD.

Peripheral biomarkers to predict the diagnosis of bipolar disorder from major depressive disorder in adolescents

The onset of bipolar disorder (BD) occurs in childhood or adolescence in half of the patients. Early stages of BD usually present depressive episodes, which makes it difficult to be distinguished from major depressive disorder (MDD). Objective biomarkers for discriminating BD from MDD in adolescent patients are limited. We collected basic demographic data and the information of the first blood examination performed after the admission to psychiatry unit of BD and MDD inpatients during 2009-2018. We recruited 261 adolescents (aged from 10 to 18), including 160 MDD and 101 BD. Forward-Stepwise Selection of binary logistic regression was used to construct predictive models for the total sample and subgroups by gender. Independent external validation was made by 255 matched patients from another hospital in China. Regression models of total adolescents, male and female subgroups showed accuracy of 73.3%, 70.6% and 75.2%, with area under curves (AUC) as 0.785, 0.816 and 0.793, respectively. Age, direct bilirubin (DBIL), lactic dehydrogenase (LDH), free triiodothyronine (FT3) and C-reactive protein (CRP) were final factors included into the models. The discrimination was well at external validation (AUC = 0.714). This study offers the evidence that accessible information of common clinical laboratory examination might be valuable in distinguishing BD form MDD in adolescents. With good diagnostic accuracies and external validation, the total regression equation might potentially be applied to individualized clinical inferences on adolescent BD patients.

Neutrophil/lymphocyte, platelet/lymphocyte and monocyte/lymphocyte ratios in patients with affective disorders

OBJECTIVE

There is substantial evidence to support that the alterations in the immune-inflammation system play a crucial role in the pathogenic mechanism of affective disorders. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) have been recently investigated as simple, rapid, and inexpensive inflammation markers. The purpose of the research is to use large-scale clinical data to study the difference of the inflammation ratios in first-episode MDD, recurrent MDD, BD depressive episodes and manic episode.

METHODS

A cross-sectional design was applied to retrospectively analyse the data that were extracted from electronic health records. A total of 16,174 Chinese affective disorder patients were enrolled in this study, and 6681 healthy subjects served as controls. The differences in the NLR, MLR, PLR and whole blood count data among different groups were compared, and the contributing factors for the occurrence of MDD and BD were analysed.

RESULTS

First-episode and recurrent MDD patients exhibited significantly elevated NLRs and MLRs compared to healthy controls. Compared with the MDD patients, the BD patients showed higher NLRs and MLRs and lower PLRs. Further analysis showed that the BD manic episode patients had significantly elevated NLRs and MLRs compared to patients with BD depressive episodes or MDD. MLR was a risk factor for the occurrence of MDD and that the NLR and MLR were risk factors for the occurrence of BD.

CONCLUSIONS

Our study highlights the role of systemic inflammation in the pathophysiology of MDD and BD, particularly during manic BD episodes.

Clinical Value of Inflammatory and Neurotrophic Biomarkers in Bipolar Disorder: A Systematic Review and Meta-Analysis

Bipolar disorder (BD) is a multifactorial chronic psychiatric disease highly defined by genetic, clinical, environmental and social risk factors. The present systematic review and meta-analysis aimed to examine the relationship between inflammatory and neurotrophic factors and clinical, social and environmental factors involved in the development and the characterization of BD. Web of Science, PubMed, PsycINFO, Scopus and Science Direct were searched by two independent reviewers. The systematic review was registered in PROSPERO (CRD42020180626). A total of 51 studies with 4547 patients with a diagnosis of BD were selected for systematic review. Among them, 18 articles were included for meta-analysis. The study found some evidence of associations between BDNF and/or inflammatory factors and different stressors and functional and cognitive impairment, but limitations prevented firm conclusions. The main finding of the meta-analysis was a negative correlation between circulating levels of BDNF and depression severity score (standardized mean difference = −0.22, Confidence Interval 95% = −0.38, −0.05, p = 0.01). Evidence indicates that BDNF has a role in the depressive component of BD. However, the poor consistency found for other inflammatory mediators clearly indicates that highly controlled studies are needed to identity precise biomarkers of this disorder.

Pro-inflammatory cytokines and suicidal behavior among patients with bipolar I disorder

OBJECTIVE

Suicidal behavior and different mood states of bipolar I disorder (BD) have been shown to be associated with dysregulated proinflammatory cytokines. Only a few studies have examined the association between inflammation and SB in BD, and the association between proinflammatory cytokines, SB, and cognitive deficits in patients with BD remains unclear.

METHODS

77 patients with BD and 61 age-/sex-matched healthy controls were recruited. Patients were divided into two groups: with suicidal ideation (SI; n = 21) and no SI (n = 56). SI was defined by a score of ≥1 in item 10 of Montgomery Åsberg Depression Rating Scale. Levels of proinflammatory cytokines, including soluble interleukin-6 receptor (sIL-6R), soluble tumor necrosis factor-α receptor type 1 (sTNF-αR1), and C-reactive protein (CRP), were measured, and cognitive function was assessed using 2-back task and Go/No-Go task.

RESULTS

Patients with SI had higher levels of sTNF-αR1 than those without SI and the controls (p = .004). BD patients with or without a history of suicide attempt had higher levels of CRP than the controls. SI was associated with serum levels of sTNF-αR1 and IL-6sR, even after additionally controlling for working memory and inhibitory control (p < .05).

CONCLUSION

This study indicates that serum levels of sTNF-αR1 have distinct differences between BD patients with or without SI, and our findings strengthen the hypothesis of a link between suicidal behavior and neuro-inflammation pathophysiology in BD.

Comparison of cognitive impairments with lipid profiles and inflammatory biomarkers in unipolar and bipolar depression

Cognitive impairments is one of important accompanied symptom in Unipolar depressive disorder (UD) and bipolar disorder (BD) that was hard to distinguish, as their diagnosis is based on behavioural observations and subjective symptoms. In this study, we could highlight the difference of cognitive ability in UD and BD by testing lipid profiles and inflammatory biomarkers in major depressive episodes (MDE). 207 subjects (96 unipolar and 111 bipolar depressed patients) were included in this study. We applied Montreal Cognitive Assessment (MoCA) to test cognitive ability. The 24-item Hamilton Depression Rating Scale was used for assessment at the beginning of treatment. A series of clinical variables and lipid profiles were collected from clinic record. We detected pro-inflammatory biomarkers Interleukin-1β (IL-1β), Interleukin-6 (IL-6), C-reaction protein (CRP) levels and brain-derived neurotrophic factor (BDNF) by enzyme linked immunosorbent assay. From the results, cognitive impairments were more popular in BD than UD, most obviously in severe cognitive impairments (MoCA score<23). And UD showed better cognitive ability than BD in MoCA, particularly in language domain. Compared lipid profiles like total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA1), Apolipoprotein B (ApoB) and lipoprotein α (Lpα), we found that ApoB was higher in BD than UD that maybe a risk factor in cognition. There was no obviously difference in TC, TG, HDL-C, LDL-C, ApoA1, or Lpα. Also, we found CRP level in BD was higher than UD, and showed no significant difference in IL-1β and IL-6 levels. Furthermore, BDNF level which was neurotrophic biomarker for cognition and mood was significantly declined in BD compared with UD. Correlation analysis showed that ApoB and CRP was negative closed associated with MoCA scores. And BDNF level was positive related with cognitive ability in MDE patients. From our results mentioned that quantitative lipid profiles and inflammatory biomarkers analysis might help to objectively identify between these disorders and up our understanding of their pathophysiology. And ApoB, CRP and BDNF could be as potential peripheral candidates in cognitive evaluation to distinguish UD and BD.