The role of macrophage polarization on bipolar disorder: Identifying new therapeutic targets.

OBJECTIVE: Bipolar disorder is a chronic, severe and disabling disease; however, its pathophysiology remains poorly understood. Recent evidence has suggested that inflammation and immune dysregulation play a significant role in the pathophysiology of bipolar disorder. This review is aimed to highlight the importance of systemic inflammation in modulating the inflammatory response of microglia and hence its potential involvement with bipolar disorder. We also discuss novel therapeutic strategies that emerge from this new research. METHOD: This article presents a theoretical synthesis of the effects of systemic inflammation on the immune response of the central nervous system in bipolar disorder. The complex relationship between stress, pro-inflammatory cytokines and microglial dysfunction is summarized, emphasizing the role of the kynurenine pathway in this process and, consequently, their effects on neuronal plasticity. RESULTS: Bipolar patients demonstrate increased serum levels of pro-inflammatory cytokines (interleukin-1ß, interleukin-6 and tumor necrosis factor-α) and lower hypothalamic-pituitary-adrenal axis sensitivity. This imbalance in the immune system promotes a change in blood-brain barrier permeability, leading to an inflammatory signal spread in the central nervous system from the periphery, through macrophages activation (M1 polarization). Chronic microglial activation can result in neuronal apoptosis, neurogenesis inhibition, hippocampal volume reduction, lower neurotransmitters synthesis and cytotoxicity, by increasing glutamate production and kynurenine metabolism. CONCLUSIONS: This review provides an overview of the mechanisms involved in the immune system imbalance and its potential involvement in the pathophysiology of bipolar disorder. Consequently, new strategies that normalize the immune-inflammatory pathways may provide a valuable therapeutic target for the treatment of these disorders.

Inflammation and damage-associated molecular patterns in major psychiatric disorders.

BACKGROUND: Emerging evidence indicates that inflammation plays an important role as a mechanism underlying mental disorders. However, most of the research on inflammatory mechanisms focuses on serum levels of interleukins and very few studies have investigated molecules that initiate and expand innate immune pathways such as damage-associated molecular patterns (DAMPs). OBJECTIVES: This study investigated the levels of DAMPs among patients diagnosed with major depressive disorder (MDD), bipolar disorder (BD) I and II, schizophrenia (SCZ), and generalized anxiety disorder (GAD). We quantified serum levels of heat shock proteins (HSPs) 70 and 60 and of S100 calcium-binding protein B (S100B). METHODS: Serum levels of HSP70, HSP60, and S100B were assessed in a sample of participants with psychiatric disorders (n = 191) and a control group (CT) (n = 59) using enzyme-linked immunosorbent assay (ELISA). RESULTS: Serum HSP70 concentrations were significantly higher in the MDD group compared to the CT, SCZ, and BD groups. The GAD group had higher concentrations of HSP70 than the SCZ group. Exploring associations with medications, lithium (p = 0.003) and clozapine (p = 0.028) were associated with lower HSP70 levels. Approximately 64% of the sample had DAMPs levels below the limits of detection indicated by the respective ELISA kit. CONCLUSION: This was the first study to assess DAMPs levels in a transdiagnostic sample. Our preliminary findings suggest that HSP70 may be associated with MDD pathophysiology. Medications such as lithium and clozapine were associated with lower HSP70 levels in BD and SCZ groups, respectively. Therefore, it is worth mentioning that all participants were medicated and many psychotropic drugs exert an anti-inflammatory effect, possibly reducing the signs of inflammation.

Differentially regulated targets in the fast-acting antidepressant effect of (R)-ketamine: A systems biology approach.

Approximately two-thirds of patients with major depressive disorder (MDD) fail to respond to conventional antidepressants, suggesting that additional mechanisms are involved in the MDD pathophysiology. In this scenario, the glutamatergic system represents a promising therapeutic target for treatment-resistant depression. To our knowledge, this is the first study using semantic approach with systems biology to identify potential targets involved in the fast-acting antidepressant effects of ketamine and its enantiomers as well as identifying specific targets of (R)-ketamine. We performed a systematic review, followed by a semantic analysis and functional gene enrichment to identify the main biological processes involved in the therapeutic effects of these agents. Protein-protein interaction networks were constructed, and the genes exclusively regulated by (R)-ketamine were explored. We found that the regulation of α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid (AMPA) receptor and N-methyl-d-aspartate (NMDA) receptor subunits-Postsynaptic Protein 95 (PSD-95), Brain Derived Neurotrophic Factor (BDNF), and Tyrosine Receptor Kinase B (TrkB) are shared by the three-antidepressant agents, reinforcing the central role of the glutamatergic system and neurogenesis on its therapeutic effects. Differential regulation of Transforming Growth Factor Beta 1 (TGF-ß1) receptors-Mitogen-Activated Protein Kinases (MAPK's), Receptor Activator of Nuclear Factor-Kappa Beta Ligand (RANKL), and Serotonin Transporter (SERT) seems to be particularly involved in (R)-ketamine antidepressant effects. Our data helps further studies investigating the relationship between these targets and the mechanisms of (R)-ketamine and searching for other therapeutic compounds that share the regulation of these specific biomolecules. Ultimately, this study could contribute to improve the fast management of depressive-like symptoms with less detrimental side effects than ketamine and (S)-ketamine.

Public perceptions of psychiatric, justice-involved, and elderly populations during the COVID-19 pandemic.

The novel coronavirus disease (COVID-19) has had a significant global impact, with all countries facing the challenge of mitigating its spread. An unprecedented shortage of medical resources has raised concerns regarding allocation and prioritization of supplies, which may exacerbate social discrepancies for already vulnerable populations. As public opinion can impact healthcare policies, we aimed to characterize perceptions of psychiatric, forensic psychiatry, correctional, and elderly populations regarding COVID-19-related issues. This web-based study recruited participants (n = 583) from the general population in North America. The survey included perceptions of the pandemic, hypothetical scenarios on resource prioritization, and Likert scale questions. The majority of participants were cisgender female (72.7%), aged 31-74 years (80.0%), married (48.0%), retired (52.7%), resided in Canada (73.9%), had a college/university degree (50.9%) and had never worked in healthcare (66.21%). Most respondents reported not having a criminal history (95.88%), or a psychiatric disorder (78.73%). Perceptions of vulnerable populations were significantly different for resource allocation and prioritization (e.g., ventilator and vaccine resources, all p < 0.001). Healthcare workers and the elderly were commonly ranked the highest priority for resources, while forensic psychiatry and correctional populations were given the lowest priority. A high rate of disagreement was found for the more stigmatizing questions in the survey (all p < 0.0001). Our results suggest that perception from members of the general public in North America is aligned with current practices for resource allocation. However, individuals that already face social and health disparities may face additional opposition in decision-making for COVID-19 resources.

Potential Candidates for Biomarkers in Bipolar Disorder: A Proteomic Approach through Systems Biology.

Bipolar disorder (BD) is one of the most disabling diseases characterized by severe humor fluctuation. It is accompanied by cognitive and functional impairment in addiction to high suicide rates. BD is often underdiagnosed and treated incorrectly because many of the reported symptoms are not exclusive to the disorder. Once the diagnosis is exclusively clinical, it is not possible to state precisely. From that, proteomic approaches were used to identify, in a large scale, all proteins involved in cellular or tissue processes. This review aggregate data from blood proteomes, by using protein association network, of subjects with BD and healthy controls to suggest dysfunctional molecular pathways involved in disease. Original articles containing proteomic analysis were searched in PubMed. Seven studies were selected and data were extracted for posterior analysis. A protein-protein interaction network was created by STRING database. A final set of proteins in this network were employed as input in ClueGO and, the main biological process was visualized using R package pathview. The analysis revealed proteins associated with many biological processes, including growth and endocrine regulation, iron transportation, protease inhibition, protection against pathogens and cholesterol transport. Moreover, pathway analysis indicated the association of uncovered proteins with two main metabolic pathways: complement system and coagulation cascade. Thus, a better understanding on the pathophysiology of psychiatric disorders and the identification of potential biomarker candidates are essential to improve diagnostic, prognostic and design pharmacological strategies.

Is (R)-ketamine a potential therapeutic agent for treatment-resistant depression with less detrimental side effects? A review of molecular mechanisms underlying ketamine and its enantiomers.

Approximately one-third of individuals with major depressive disorder are resistant to conventional antidepressants (i.e., monoamine-based therapies), and, even among respondents, a proper therapeutic effect may require weeks of treatment. Ketamine, a racemic mixture of the two enantiomers, (R)-ketamine and (S)-ketamine, is an N-methyl-d-aspartate receptor (NMDAR) antagonist and has been shown to have rapid-acting antidepressant properties in patients with treatment-resistant depression (TRD). Although (R)-ketamine has a lower affinity for NMDAR, it presents greater potency and longer-lasting antidepressant properties, with no major side effects, than racemic ketamine or (S)-ketamine in preclinical findings. Thereby, ketamine and its enantiomers have not only an antagonistic effect on NMDAR but also a strong synaptogenic-modulatory effect, which is impaired in TRD pathophysiology. In this review, we summarize the current evidence regarding the modulation of neurotransmission, neuroplasticity, and neural network activity as putative mechanisms of these rapid-acting antidepressants, highlighting differences on intracellular signaling pathways of synaptic proteins such as mammalian target of rapamycin (mTOR), extracellular signal-regulated kinase (ERK) and brain-derived neurotrophic factor (BDNF). In addition, we discuss probable mechanisms involved in the side effects of ketamine and its enantiomers.

Stigmatization of psychiatric and justice-involved populations during the COVID-19 pandemic.

Psychiatric and justice-involved populations are known to be stigmatized and particularly vulnerable to adverse outcomes during COVID-19. The increased attention toward vulnerable populations from healthcare authorities, the media, and the general public has made it critical to uncover any developing stigmatization toward these groups and the possible consequences. The prioritization of public safety and shift in the prioritization of resource allocation and service delivery could lead to a rise in negative perceptions toward these already stigmatized groups. Thus, it is imperative to consider how the unique characteristics of vulnerable groups may impact their physical and mental health as well as their care during this pandemic. In this paper, we describe the challenges that psychiatric, correctional, and forensic psychiatry populations have faced during COVID-19 and how a rise in stigmatization could lead to adverse outcomes. Specifically, we outline the influence of the media on public perceptions and how stigmatization may be reflected in the allocation of resources, policies, and related decision-making during COVID-19.

The costs of coping: Different strategies to deal with social defeat stress might come with distinct immunologic, neuroplastic, and oxidative stress consequences in male Wistar rats.

The impact of stress on health and well-being is determined by the ability of an individual to cope with challenges imposed by the stressor. Animals exposed to social defeat stress show different patterns of response during confrontations, leading to distinct stress-induced consequences. Using an established resident-intruder paradigm, we explored the outcomes of adopting active or passive coping strategies during a social defeat protocol over peripheral and central nervous system (CNS) levels of inflammatory cytokines, growth factors, glucocorticoid, and oxidative stress markers in male Wistar rats. Animals that presented short latency to assume a defeated posture during confrontation-considered as susceptible to stress-exhibited increased levels of brain-derived neurotrophic factor (BDNF) in the amygdala (AMY) and in the bed nucleus of the stria terminalis (BNST), and decreased lipid peroxidation in the CNS, suggesting changes in antioxidative defenses as well as stress-induced neuroadaptations. On the other hand, animals with longer latencies to assume a submissive posture-considered to be resilient to stress-presented lower levels of CNS BDNF compared to short-latency animals and decreased enzymatic antioxidant defenses in the CNS in comparison to controls, which might indicate an increased risk of central oxidative damage. From the results, behavioral reactivity cannot be considered a predictor of success in responding to stress; however, the findings of this study reinforce the idea that exposure to stress has no predetermined negative effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Reduction of hippocampal IL-6 levels in LPS-injected rats following acute exendin-4 treatment.

Preclinical evidence on the role of glucagon-like peptide-1 receptor (GLP-1r) agonists in the brain led to an increased interest in repurposing these compounds as a therapy for central nervous system (CNS) disorders and associated comorbidities. We aimed to investigate the neuroprotective effects of acute treatment with exendin (EX)-4, a GLP-1r agonist, in an animal model of inflammation. We evaluated the effect of different doses of EX-4 on inflammatory, neurotrophic, and oxidative stress parameters in the hippocampus and serum of lipopolysaccharide (LPS)-injected animals. Male Wistar rats were injected with LPS (0.25 mg/kg i.p.) and treated with different doses of EX-4 (0.1, 0.3, or 0.5 µg/kg i.p.). Sickness behavior was assessed by locomotor activity and body weight, and depressive-like behavior was also evaluated using forced swim test (FST). Brain-derived neurotrophic factor (BDNF), thiobarbituric acid reactive species (TBARS), and interleukin (IL)-6 were quantified in the serum and hippocampus. Glycemia was also analyzed pre- and post-EX-4 treatment. LPS groups exhibited decreased frequency of crossing and reduced body weight (p < 0.001), while alterations on FST were not observed. The higher dose of EX-4 reduced IL-6 in the hippocampus of LPS-injected animals (p = 0.018), and EX-4 per se reduced TBARS serum levels with a modest antioxidant effect in the LPS groups (p ≤ 0.005). BDNF hippocampal levels seemed to be increased in the LPS+EX-4 0.5 group compared with LPS+Saline (p > 0.05). Our study provides evidence on acute anti-inflammatory effects of EX-4 in the hippocampus of rats injected with LPS, contributing to future studies on repurposing compounds with potential neuroprotective properties.

BDNF prevents central oxidative damage in a chronic unpredictable mild stress model: The possible role of PRDX-1 in anhedonic behavior.

Prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis and sustained increase of glucocorticoids have been evidenced in major depression and are related to changes involving neurotrophins and markers of oxidative stress in response to inflammation. This study aimed to evaluate central measures of brain-derived neurotrophic factor (BDNF), oxidative damage and total antioxidant capacity in rats submitted to chronic unpredictable mild stress (CUMS), as well as to investigate the relationship between BDNF levels and differentially processes. For this purpose, male Wistar rats were submitted to CUMS for six weeks. Based on a sucrose preference test (SPT), the animals were divided into anhedonic or non-anhedonic clusters. Afterwards, forced swim test (FST) and open field test (OFT) were performed, and the animals were euthanized. Brain tissue was collected, followed by quantification of oxidative damage, total antioxidant capacity and BDNF levels. Anhedonic behavior was evidenced in stress-susceptible animals through decreased sucrose preference. No differences were found in FST or OFT results. We observed increased BDNF levels in the hippocampus (HPC) of animals exposed to the CUMS protocol, accompanied by decreased total antioxidant capacity, despite the absence of oxidative damage to lipids and proteins. Moreover, we used a bioinformatics approach to identify proteins involved in oxidative stress and inflammation pathways, which were differentially expressed in anhedonic animals from other studies with similar experimental protocol. expressed proteins (DEP) involved in oxidative stress and inflammatory biological Anhedonic behavior was associated with peroxiredoxin-1 (PRDX-1) up-regulation and down-regulation of proteins involved with apoptotic and inflammation signaling (RELA, ASK-1 and TAK-1) in the HPC. Taken together, these data suggest that BDNF and PRDX-1 might be involved in initial stress response, playing a compensatory role by preventing oxidative damage to lipids and proteins through the modulation of antioxidant defense after CUMS in anhedonic animals.

Effects of lithium on inflammatory and neurotrophic factors after an immune challenge in a lisdexamfetamine animal model of mania.

OBJECTIVE: To evaluate whether an animal model of mania induced by lisdexamfetamine dimesylate (LDX) has an inflammatory profile and whether immune activation by lipopolysaccharides (LPS) has a cumulative effect on subsequent stimuli in this model. We also evaluated the action of lithium (Li) on inflammatory and neurotrophic factors. METHODS: Adult male Wistar rats were subjected to an animal model of mania. After the open-field test, they were given LPS to induce systemic immune activation. Subsequently, the animals' blood was collected, and their serum levels of brain-derived neurotrophic factor and inflammatory markers (tumor necrosis factor [TNF]-α, interleukin [IL]-6, IL-1ß, IL-10, and inducible nitric oxide synthase [iNOS]) were measured. RESULTS: LDX induced hyperactivity in the animals, but no inflammatory marker levels increased except brain-derived neurotrophic factor (BDNF). Li had no effect on serum BDNF levels but prevented iNOS levels from increasing in animals subjected to immune activation. CONCLUSION: Although Li prevented an LPS-induced increase in serum iNOS levels, its potential anti-inflammatory effects in this animal model of mania were conflicting.

Agmatine as a potential therapeutic intervention in bipolar depression: the preclinical landscape.

INTRODUCTION: Present antidepressant treatments are only helpful in a quarter of patients with bipolar depression, and new strategies are warranted. Increasing evidence suggests that accelerated polyamine metabolism is associated with the pathophysiology of depression. Polyamines regulate stress responses, inflammation, and neuronal signaling in the central and enteric nervous system. Agmatine is a promising target of altered polyamine metabolism considering its unique ability to regulate intracellular polyamine content and neuroprotective effects. Areas covered: This review discusses the polyamine system and its relationship to the central and enteric nervous system, focusing on results from preclinical studies supporting the relationship between agmatine and the pathophysiology of depression. We also discussed the main mechanisms underlying the antidepressant and neuroprotective effects of agmatine. Expert opinion: Our review points out the possible relationship between polyamines and the pathophysiology of depression. It discusses the efficacy of agmatine in several models of depressive-like behaviour, and suggests that it may prove to be an efficacious adjunctive treatment in bipolar depression. Furthermore, it discusses a proposed pathway linking systemic inflammation, observed in a subset of bipolar disorder patients, to abnormal polyamine metabolism and associated changes in the epithelial gut barrier and blood-brain barrier.

Comparative study on the effects of cigarette smoke exposure, ethanol consumption and association: Behavioral parameters, apoptosis, glial fibrillary acid protein and S100ß immunoreactivity in different regions of the rat hippocampus.

Exposure to cigarette smoke and ethanol are proposed to trigger neurotoxicity, apoptosis, and to impair neuronal signaling. However, it is little known how the combination of both might trigger astrogliosis and the morphological changes capable of affecting a differential susceptibility of hippocampal regions to these licit drugs. The present study investigated the chronic effects of exposure to cigarette smoke and/or ethanol on behavioral parameters, apoptosis, and alteration in immunoreactivity of glial fibrillary acid protein (GFAP) and S100ß in the CA1, CA3, and dentate gyrus (DG) of the rat hippocampus. Adult male Wistar rats (n = 32) were divided into four groups: vehicle (VE, glucose 3% in water, 10 mL/kg), cigarette smoke (TOB, total 12 cigarettes per day), ethanol (ethanol, 2 g/kg), and cigarette smoke plus ethanol (TOB plus ethanol, total 12 cigarettes per day plus ethanol 2 g/kg) for 54 days. The groups were submitted to tail-flick, open-field, and inhibitory avoidance tasks. The results showed that ethanol per se worsened the short-term memory. The association between TOB and ethanol increased the immunoreactivity of cleaved caspase-3 in the CA3 and DG regions. The TOB plus ethanol group showed a lower immunoreactivity to GFAP in all regions of the hippocampus. In addition, ethanol and TOB per se also reduced the immunoreactivity for GFAP in the DG. Ethanol increased S100ß immunoreactivity only in the DG. In conclusion, this study showed that only ethanol worsened short-term memory, and the DG became more susceptible to changes in the markers investigated. This evidence suggests that DG is more sensitive to neurotoxicity induced by cigarette smoke and ethanol.

Anhedonic-like behavior correlates with IFNγ serum levels in a two-hit model of depression.

Stress is implicated in the etiology of major depressive disorder (MDD) and leads to the activation of proinflammatory pathways, which are recognized to induce depressive symptoms. For instance, depression is commonly observed in patients with hepatitis C and cancer under IFN therapy, and high levels of inflammatory cytokines are described in the serum of individuals with MDD - which indicate a multi-system aspect of psychiatric disorders. Thus, we evaluated the effects of a two-hit model of depression on peripheral and CNS inflammatory, neurotrophic, and oxidative stress parameters and behavior. Male Wistar rats were submitted to lipopolysaccharide (LPS) injections, followed by a chronic unpredictable mild stress (CUMS) protocol. Rats exposed to CUMS (CUMS + groups) exhibited reduced body weight, sucrose consumption and preference as well as an increased score of coat state and locomotor behavior. Interestingly, higher IFNγ serum levels were observed in the LPS/CUMS + group, which were further correlated with reduced sucrose consumption. Hypertrophy of adrenal gland was also observed in CUMS+, and splenic hypertrophy was exclusive of LPS-injected animals. Brain-derived neurotrophic factor (BDNF) levels were decreased in the serum of CUMS + animals, while no differences were found in the hippocampus and on lipid peroxidation levels. Besides corroborating the effectiveness of the CUMS model on inducing depressive-like behavior, our findings suggest that the combination of different etiological and pathophysiological components of MDD may provide with a more translational approach. Also, the correlation of increased IFNγ peripheral levels with an anhedonic-like phenotype reinforce the contemporary concept of psychiatric disorders being considered multi-system inflammatory diseases.

Attenuated inflammatory response of monocyte-derived macrophage from patients with BD: a preliminary report.

BACKGROUND: Innate immune system dysfunction has been recognized as an important element in the pathophysiology of bipolar disorder (BD). We aimed to investigate whether there are differences in the response of macrophages derived from patients in the early stages and late stages of BD and healthy subjects. METHODS: Human monocytes purified from peripheral blood mononuclear cells (PBMCs) of patients with BD type I (n = 18)-further classified into early- and late stage BD patients according to their functioning- and from healthy individuals (n = 10) were differentiated into macrophages in vitro. Monocyte-derived macrophages (M) were exposed to IFNγ plus LPS-M(IFNγ + LPS)- or IL-4-M(IL-4)-to induce their polarization into the classical (also called M1) or alternative (also called M2) activation phenotypes, respectively; or either Mψ were not exposed to any stimuli characterizing the resting state (denominated M0). In vitro secretion of cytokines, such as IL-1ß, IL-6, IL-10, and TNF-α, was used as an index of macrophage activity. RESULTS: M(IFNγ + LPS) from late-stage BD patients produced less amount of IL-1ß, IL-6, and IL-10 when compared to early-stage BD patients and healthy controls. Following alternative activation, M(IL-4) derived from late-stage patients secreted less IL-6 compared to the other groups. TNFα was less secreted by all macrophage phenotypes derived from late-stage patients when compared to healthy controls only (p < 0.005). Mψ from late-stage patients exhibited lower production of IL-1ß and IL-10 compared to macrophages from healthy subjects and early-stage patients respectively. Interestingly, cytokines secretion from M(IFNγ + LPS), M(IL-4) and Mψ were similar between early-stage patients and healthy controls. CONCLUSION: Our results suggest a progressive dysfunction in the response of peripheral innate immune cells of BD patients in the late stages of the illness. This failure in the regulation of the immune system function may be implicated in the multisystemic progression of BD.

Inflammation and damage-associated molecular patterns in major psychiatric disorders

Abstract Background Emerging evidence indicates that inflammation plays an important role as a mechanism underlying mental disorders. However, most of the research on inflammatory mechanisms focuses on serum levels of interleukins and very few studies have investigated molecules that initiate and expand innate immune pathways such as damage-associated molecular patterns (DAMPs). Objectives This study investigated the levels of DAMPs among patients diagnosed with major depressive disorder (MDD), bipolar disorder (BD) I and II, schizophrenia (SCZ), and generalized anxiety disorder (GAD). We quantified serum levels of heat shock proteins (HSPs) 70 and 60 and of S100 calcium-binding protein B (S100B). Methods Serum levels of HSP70, HSP60, and S100B were assessed in a sample of participants with psychiatric disorders (n = 191) and a control group (CT) (n = 59) using enzyme-linked immunosorbent assay (ELISA). Results Serum HSP70 concentrations were significantly higher in the MDD group compared to the CT, SCZ, and BD groups. The GAD group had higher concentrations of HSP70 than the SCZ group. Exploring associations with medications, lithium (p = 0.003) and clozapine (p = 0.028) were associated with lower HSP70 levels. Approximately 64% of the sample had DAMPs levels below the limits of detection indicated by the respective ELISA kit. Conclusion This was the first study to assess DAMPs levels in a transdiagnostic sample. Our preliminary findings suggest that HSP70 may be associated with MDD pathophysiology. Medications such as lithium and clozapine were associated with lower HSP70 levels in BD and SCZ groups, respectively. Therefore, it is worth mentioning that all participants were medicated and many psychotropic drugs exert an anti-inflammatory effect, possibly reducing the signs of inflammation.

Depression and Mania Induce Pro-inflammatory Activation of Macrophages Following Application of Serum from Individuals with Bipolar Disorder.

OBJECTIVE: Evidence has suggested that immune imbalance is involved with bipolar disorder (BD); however, its precise mechanism is poorly understood. This study investigated whether biochemical changes in the serum from BD patients could modulate the phenotype of cultured macrophages. METHODS: Eighteen subjects with BD and five healthy individuals were included in this study. The human monocyte cell line U-937 was activated with phorbol 12-myristate 13-acetate (PMA) and polarization was induced with RPMI-1640 media supplemented with 10% serum from each patient for 24 hours. Gene expression of selected M1 and M2 markers was assessed by quantitative PCR. RESULTS: Macrophages exposed to serum of manic and depressive BD patients displayed an increase of interleukin-1ß (6.40±3.47 and 9.04±5.84 vs. 0.23±0.11; p＜0.05) and tumor necrosis factor-α (2.23±0.91 and 2.03±0.45 vs. 0.62±0.24; p=0.002 and p=0.004, respectively) compared to euthymic group (there was no difference between euthymic and controls). In parallel, U-937 macrophages treated with serum of patients in acute episode displayed a down-regulation of CXCL9 (0.29±0.20 vs. 1.86±1.61; p=0.006) and CXCL10 expression (0.36±0.15 and 0.86±0.24 vs. 1.83±0.88; p＜0.000 and p=0.04) compared to the euthymia group. CONCLUSION: Our results are consistent with previous studies showing that changes in peripheral blood markers could modulate M1/M2 polarization in BD. The evidence of macrophages as source of inflammatory cytokines might be helpful to unravel how the mononuclear phagocyte system is involved in the etiology of BD.

Cell therapy in the treatment of bipolar mania in an animal model: a proof of concept study.

INTRODUCTION: The rationale of mesenchymal stem cells (MSCs) as a novel therapeutic approach in certain neurodegenerative diseases is based on their ability to promote neurogenesis. Hippocampal atrophy has been related to bipolar disorder (BD) in preclinical, imaging and postmortem studies. Therefore, the development of new strategies to stimulate the neurogenesis process in BD is crucial. OBJECTIVES: To investigate the behavioral and neurochemical changes induced by transplantation of MSCs in a model of mania-like behavior induced by lisdexamfetamine dimesylate (LDX). METHODS: Wistar rats (n=65) received one oral daily dose of LDX (10 mg/kg) or saline for 14 days. On the 8th day of treatment, the animals additionally received intrahippocampal saline or MSC (1 µL containing 25,000 cells) or lithium (47.5 mg/kg) as an internal experimental control. Two hours after the last administration, behavioral and neurochemical analyses were performed. RESULTS: LDX-treated rats had increased locomotor activity compared to saline-saline rats (p=0.004), and lithium reversed LDX-related hyperactive behavior (p<0.001). In contrast, the administration of MSCs did not change hyperlocomotion, indicating no effects of this treatment on LDX-treated rats (p=0.979). We did not find differences between groups in BDNF levels (p>0.05) in the hippocampus of rats. CONCLUSION: Even though these results suggest that a single intrahippocampal injection of MSCs was not helpful to treat hyperactivity induced by LDX and neither influenced BDNF secretion, we cannot rule out the possible therapeutic effects of MSCs. Further research is required to determine direct effects of LDX on brain structures as well as in other pathophysiological targets related to BD.

The effect of taurine and enriched environment on behaviour, memory and hippocampus of diabetic rats.

Diabetes mellitus (DM) has been studied recently as a major cause of cognitive deficits, memory and neurodegenerative damage. Taurine and enriched environment have stood out for presenting neuroprotective and stimulating effects that deserve further study. In this paper, we examined the effects of taurine and enriched environment in the context of diabetes, evaluating effects on behaviour, memory, death and cellular activity. Eighty-eight Wistar rats were divided into 2 groups (E=enriched environment; C=standard housing). Some animals (24/group) underwent induction of diabetes, and within each group, some animals (half of diabetics (D) and half of non-diabetics (ND)/group) were treated for 30days with taurine (T). Untreated animals received saline (S). In total, there were eight subgroups: DTC, DSC, NDTC, NDSC, DTE, DSE, NDTE and NDSE. During the experiment, short-term memory was evaluated. After 30th day of experiment, the animals were euthanized and was made removal of brains used to immunohistochemistry procedures for GFAP and cleaved caspase-3. As a result, we observed that animals treated with taurine showed better performance in behavioural and memory tasks, and the enriched environment had positive effects, especially in non-diabetic animals. Furthermore, taurine and enriched environment seemed to be able to interfere with neuronal apoptosis and loss of glial cells, and in some instances, these two factors seemed to have synergistic effects. From these data, taurine and enriched environment may have important neurostimulant and neuroprotective effects.

Effects of lithium on inflammatory and neurotrophic factors after an immune challenge in a lisdexamfetamine animal model of mania

Objective: To evaluate whether an animal model of mania induced by lisdexamfetamine dimesylate (LDX) has an inflammatory profile and whether immune activation by lipopolysaccharides (LPS) has a cumulative effect on subsequent stimuli in this model. We also evaluated the action of lithium (Li) on inflammatory and neurotrophic factors. Methods: Adult male Wistar rats were subjected to an animal model of mania. After the open-field test, they were given LPS to induce systemic immune activation. Subsequently, the animals' blood was collected, and their serum levels of brain-derived neurotrophic factor and inflammatory markers (tumor necrosis factor [TNF]-α, interleukin [IL]-6, IL-1β, IL-10, and inducible nitric oxide synthase [iNOS]) were measured. Results: LDX induced hyperactivity in the animals, but no inflammatory marker levels increased except brain-derived neurotrophic factor (BDNF). Li had no effect on serum BDNF levels but prevented iNOS levels from increasing in animals subjected to immune activation. Conclusion: Although Li prevented an LPS-induced increase in serum iNOS levels, its potential anti-inflammatory effects in this animal model of mania were conflicting.