Role of glutathione in neuroprotective effects of mood stabilizing drugs lithium and valproate

Prefrontal Glutathione Levels in Major Depressive Disorder Are Linked to a Lack of Positive Affect

Major depressive disorder (MDD) is one of the most common neuropsychiatric disorders, with symptoms including persistent sadness and loss of interest. MDD is associated with neurochemical alterations in GABA, glutamate, and glutamine levels but, to date, few studies have examined changes in glutathione (GSH) in MDD. This study investigated changes in GSH in an unmedicated group of young adults, including 46 participants with current (n = 12) or past MDD (n = 34) and 20 healthy controls. Glutathione levels were assessed from GSH-edited magnetic resonance (MR) spectra, acquired from a voxel in the left prefrontal cortex, and depressive symptoms were evaluated with validated questionnaires and clinical assessments. Cortisol levels were also assessed as a marker for acute stress. Participants with current MDD demonstrated elevated GSH in comparison to participants with past MDD and controls, although the results could be influenced by differences in tissue composition within the MRS voxel. In addition, participants with both current and past MDD showed elevated cortisol levels in comparison to controls. No significant association was observed between GSH and cortisol levels, but elevated GSH levels were associated with a decrease in positive affect. These results demonstrate for the first time that elevated GSH in current but not past depression may reflect a state rather than a trait neurobiological change, related to a loss of positive affect.

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.

Potential Role of Glutathione Antioxidant Pathways in the Pathophysiology and Adjunct Treatment of Psychiatric Disorders

Oxidative stress is defined as the imbalance between the production of free radicals and their removal by antioxidants, leading to accumulation and subsequent organ and tissue damage. Antioxidant status and its role in the accumulation of free radicals has been observed in a number of psychological disorders. Glutathione is commonly referred to as the principal antioxidant of the brain and, therefore, plays a critical role in maintaining redox homeostasis. Reduced levels of glutathione in the brain increase its vulnerability to oxidative stress, and may be associated with the development and progression of several psychiatric disorders. Within this review, we focus on analyzing potential associations between the glutathione antioxidant pathway and psychiatric disorders: major depressive disorder, schizophrenia, bipolar disorder, and generalized anxiety disorder. Our research suggests that studies regarding these four disorders have shown decreased levels of GSH in association with diseased states; however, conflicting results note no significant variance in glutathione pathway enzymes and/or metabolites based on diseased state. In studying the potential of NAC administration as an adjunct therapy, various studies have shown NAC to augment therapy and/or aid in symptomatic management for psychiatric disorders, while contrasting results exist within the literature. Based on the conflicting findings throughout this review, there is room for study regarding the potential role of glutathione in the development and progression of psychiatric disorders. Our findings further suggest a need to study such pathways with consideration of the interactions with first-line pharmacotherapy, and the potential use of antioxidants as supplemental therapy.

Is lithium neuroprotective? An updated mechanistic illustrated review

Neurodegeneration is a pathological process characterized by progressive neuronal impairment, dysfunction, and loss due to mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Many studies have shown that lithium protects against neurodegeneration. Herein, we summarize recent clinical and laboratory studies on the neuroprotective effects of lithium against neurodegeneration and its potential to modulate mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Recent findings indicate that lithium regulates critical intracellular pathways such as phosphatidylinositol-3 (PI3)/protein kinase B (Akt)/glycogen synthase kinase-3 (GSK3β) and PI3/Akt/response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF). We queried PubMed, Web of Science, Scopus, Elsevier, and other related databases using search terms related to lithium and its neuroprotective effect in various neurodegenerative diseases and events from January 2000 to May 2022. We reviewed the major findings and mechanisms proposed for the effects of lithium. Lithium's neuroprotective potential against neural cell degeneration is mediated by inducing anti-inflammatory factors, antioxidant enzymes, and free radical scavengers to prevent mitochondrial dysfunction. Lithium effects are regulated by two essential pathways: PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF. Lithium acts as a neuroprotective agent against neurodegeneration by preventing inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction using PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF signaling pathways.

"Gingival Soft Tissue Integrative" Lithium Disilicate Glass-Ceramics with High Mechanical Properties and Sustained-Release Lithium Ions

Due to their good mechanical performances and high biocompatibility, all-ceramic materials are widely applied in clinics, especially in orthopedic and dental areas. However, the "hard" property negatively affects its integration with "soft" tissue, which greatly limits its application in soft tissue-related areas. For example, dental implant all-ceramic abutments should be well integrated with the surrounding gingival soft tissue to prevent the invasion of bacteria. Mimicking the gingival soft tissue and dentine integration progress, we applied the modified ion-exchange technology to "activate" the biological capacity of lithium disilicate glass-ceramics, via introducing OH^- to weaken the stability of Si-O bonds and release lithium ions to promote multi-reparative functions of gingival fibroblasts. The underlying mechanism was found to be closely related to the activation of mitochondrial activity and oxidative phosphorylation. In addition, during the ion-exchange process, the larger radius sodium ions (Na⁺) replaced the smaller radius lithium ions (Li⁺), so that the residual compressive stress was applied to the glass-ceramics surface to counteract the tensile stress, thus improving the mechanical properties. This successful case in simultaneous improvement of mechanical properties and biological activities proves the feasibility of developing "soft tissue integrative" all-ceramic materials with high mechanical properties. It proposes a new strategy to develop advanced bioactive and high strength all-ceramic materials by modified ion-exchange, which can pave the way for the extended applications of such all-ceramic materials in soft tissue-related areas.

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.

Antioxidant defense system in the prefrontal cortex of chronically stressed rats treated with lithium

Background

This study aimed to investigate the effects of lithium treatment on gene expression and activity of the prefrontal antioxidant enzymes: copper, zinc superoxide dismutase (SOD1), manganes superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPx) in animals exposed to chronic restraint stress (CRS).

Methods

The investigated parameters were quantified using real-time RT-PCR, Western blot analyses, and assays of enzyme activities.

Results

We found that lithium treatment decreased gene expression of SOD2, as well as the activities of SOD1 and SOD2 in chronically stressed rats to the levels found in unstressed animals. However, lithium treatment in animals exposed to CRS increased prefrontal GPx activity to the levels found in unstressed animals.

Conclusions

These findings confirm that treatment with lithium induced the modulation of prefrontal antioxidant status in chronically stressed rats. Our results may be very important in biomedical research for understanding the role of lithium in maintaining the stability of prefrontal antioxidant defense system in neuropsychiatric disorders caused by chronic stress.

Lithium and Atypical Antipsychotics: The Possible WNT/β Pathway Target in Glaucoma

Glaucoma is a progressive neurodegenerative disease that represents the major cause of irreversible blindness. Recent findings have shown which oxidative stress, inflammation, and glutamatergic pathway have main roles in the causes of glaucoma. Lithium is the major commonly used drug for the therapy of chronic mental illness. Lithium therapeutic mechanisms remain complex, including several pathways and gene expression, such as neurotransmitter and receptors, circadian modulation, ion transport, and signal transduction processes. Recent studies have shown that the benefits of lithium extend beyond just the therapy of mood. Neuroprotection against excitotoxicity or brain damages are other actions of lithium. Moreover, recent findings have investigated the role of lithium in glaucoma. The combination of lithium and atypical antipsychotics (AAPs) has been the main common choice for the treatment of bipolar disorder. Due to the possible side effects gradually introduced in therapy. Currently, no studies have focused on the possible actions of AAPs in glaucoma. Recent studies have shown a down regulation of the WNT/β-catenin pathway in glaucoma, associated with the overactivation of the GSK-3β signaling. The WNT/β-catenin pathway is mainly associated with oxidative stress, inflammation and glutamatergic pathway. Lithium is correlated with upregulation the WNT/β-catenin pathway and downregulation of the GSK-3β activity. Thus, this review focuses on the possible actions of lithium and AAPs, as possible therapeutic strategies, on glaucoma and some of the presumed mechanisms by which these drugs provide their possible benefit properties through the WNT/β-catenin pathway.

Lithium: a potential therapeutic strategy in obsessive-compulsive disorder by targeting the canonical WNT/β pathway

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder characterized b-y recurrent and distinctive obsessions and/or compulsions. The etiologies remain unclear. Recent findings have shown that oxidative stress, inflammation, and the glutamatergic pathway play key roles in the causes of OCD. However, first-line therapies include cognitive-behavioral therapy but only 40% of the patients respond to this first-line therapy. Research for a new treatment is mandatory. This review focuses on the potential effects of lithium, as a potential therapeutic strategy, on OCD and some of the presumed mechanisms by which lithium provides its benefit properties. Lithium medication downregulates GSK-3β, the main inhibitor of the WNT/β-catenin pathway. The activation of the WNT/β-catenin could be associated with the control of oxidative stress, inflammation, and glutamatergic pathway. Future prospective clinical trials could focus on lithium and its different and multiple interactions in OCD.

Spatiotemporal evaluation of the mouse embryonic redox environment and histiotrophic nutrition following treatment with valproic acid and 1,2-dithiole-3-thione during early organogenesis

Redox regulation during metazoan development ensures that coordinated metabolic reprogramming and developmental signaling are orchestrated with high fidelity in the hypoxic embryonic environment. Valproic acid (VPA), an anti-seizure medication, is known to increase markers of oxidation and also increase the risk of neural tube defects (NTDs) when taken during pregnancy. It is unknown, however, whether oxidation plays a direct role in failed neural tube closure (NTC). Spatial and temporal fluctuations in total glutathione (GSH) and total cysteine (Cys) redox steady states were seen during a 24 h period of CD-1 mouse organogenesis in untreated conceptuses and following exposure to VPA and the Nrf2 antioxidant pathway inducer, 1,2-dithiole-3-thione (D3T). Glutathione, glutathione disulfide (GSSG), and Cys, cystine (CySS) concentrations, measured in conceptal tissues (embryo/visceral yolk sac) and fluids (yolk sac fluid/amniotic fluid) showed that VPA did not cause extensive and prolonged oxidation during the period of NTC, but instead produced transient periods of oxidation, as assessed by GSH:GSSG redox potentials, which revealed oxidation in all four conceptal compartments at 4, 10, and 14 h, corresponding to the period of heartbeat activation and NTC. Other changes were tissue and time specific. VPA treatment also reduced total FITC-Ab clearance from the medium over 3 h, indicating potential disruption of nutritive amino acid supply. Overall, these results indicated that VPA's ability to affect cellular redox status may be limited to tissue-specific windows of sensitivity during the period of NTC. The safety evaluation of drugs used during pregnancy should consider time and tissue specific redox factors.

Mitochondrial dysfunction as a critical event in the pathophysiology of bipolar disorder

The understanding of the pathophysiology of bipolar disorder (BD) remains modest, despite recent advances in neurobiological research. The mitochondrial dysfunction hypothesis of bipolar disorder has been corroborated by several studies involving postmortem brain analysis, neuroimaging, and specific biomarkers in both rodent models and humans. Evidence suggests that BD might be related to abnormal mitochondrial morphology and dynamics, neuroimmune dysfunction, and atypical mitochondrial metabolism and oxidative stress pathways. Mitochondrial dysfunction in mood disorders is also associated with abnormal Ca2+ levels, glutamate excitotoxicity, an imbalance between pro- and antiapoptotic proteins towards apoptosis, abnormal gene expression of electron transport chain complexes, and decreased ATP synthesis. This paper aims to review and discuss the implications of mitochondrial dysfunction in BD etiology and to explore mitochondria as a potential target for novel therapeutic agents.

Parkinson's Disease: Potential Actions of Lithium by Targeting the WNT/β-Catenin Pathway, Oxidative Stress, Inflammation and Glutamatergic Pathway

Parkinson's disease (PD) is one of the major neurodegenerative diseases (ND) which presents a progressive neurodegeneration characterized by loss of dopamine in the substantia nigra pars compacta. It is well known that oxidative stress, inflammation and glutamatergic pathway play key roles in the development of PD. However, therapies remain uncertain and research for new treatment is mandatory. This review focuses on the potential effects of lithium, as a potential therapeutic strategy, on PD and some of the presumed mechanisms by which lithium provides its benefit properties. Lithium medication downregulates GSK-3beta, the main inhibitor of the WNT/β-catenin pathway. The stimulation of the WNT/β-catenin could be associated with the control of oxidative stress, inflammation, and glutamatergic pathway. Future prospective clinical trials could focus on lithium and its different and multiple interactions in PD.

Lack of Autophagy Induction by Lithium Decreases Neuroprotective Effects in the Striatum of Aged Rats

The pharmacological modulation of autophagy is considered a promising neuroprotective strategy. While it has been postulated that lithium regulates this cellular process, the age-related effects have not been fully elucidated. Here, we evaluated lithium-mediated neuroprotective effects in young and aged striatum. After determining the optimal experimental conditions for inducing autophagy in loco with lithium carbonate (Li₂CO₃), we measured cell viability, reactive oxygen species (ROS) generation and oxygen consumption with rat brain striatal slices from young and aged animals. In the young striatum, Li₂CO₃ increased tissue viability and decreased ROS generation. These positive effects were accompanied by enhanced levels of LC3-II, LAMP 1, Ambra 1 and Beclin-1 expression. In the aged striatum, Li₂CO₃ reduced the autophagic flux and increased the basal oxygen consumption rate. Ultrastructural changes in the striatum of aged rats that consumed Li₂CO₃ for 30 days included electrondense mitochondria with disarranged cristae and reduced normal mitochondria and lysosomes area. Our data show that the striatum from younger animals benefits from lithium-mediated neuroprotection, while the striatum of older rats does not. These findings should be considered when developing neuroprotective strategies involving the induction of autophagy in aging.

The Role of Mitochondria in Mood Disorders: From Physiology to Pathophysiology and to Treatment

Mitochondria are cellular organelles involved in several biological processes, especially in energy production. Several studies have found a relationship between mitochondrial dysfunction and mood disorders, such as major depressive disorder and bipolar disorder. Impairments in energy production are found in these disorders together with higher levels of oxidative stress. Recently, many agents capable of enhancing antioxidant defenses or mitochondrial functioning have been studied for the treatment of mood disorders as adjuvant therapy to current pharmacological treatments. A better knowledge of mitochondrial physiology and pathophysiology might allow the identification of new therapeutic targets and the development and study of novel effective therapies to treat these specific mitochondrial impairments. This could be especially beneficial for treatment-resistant patients. In this article, we provide a focused narrative review of the currently available evidence supporting the involvement of mitochondrial dysfunction in mood disorders, the effects of current therapies on mitochondrial functions, and novel targeted therapies acting on mitochondrial pathways that might be useful for the treatment of mood disorders.

Seizure-Induced Oxidative Stress in Status Epilepticus: Is Antioxidant Beneficial?

Epilepsy is a common neurological disorder which affects patients physically and mentally and causes a real burden for the patient, family and society both medically and economically. Currently, more than one-third of epilepsy patients are still under unsatisfied control, even with new anticonvulsants. Other measures may be added to those with drug-resistant epilepsy. Excessive neuronal synchronization is the hallmark of epileptic activity and prolonged epileptic discharges such as in status epilepticus can lead to various cellular events and result in neuronal damage or death. Unbalanced oxidative status is one of the early cellular events and a critical factor to determine the fate of neurons in epilepsy. To counteract excessive oxidative damage through exogenous antioxidant supplements or induction of endogenous antioxidative capability may be a reasonable approach for current anticonvulsant therapy. In this article, we will introduce the critical roles of oxidative stress and further discuss the potential use of antioxidants in this devastating disease.

Role of magnetic resonance spectroscopy in cerebral glutathione quantification for youth mental health: A systematic review

AIM

Oxidative stress is strongly implicated in many psychiatric disorders, which has resulted in the development of new interventions to attempt to perturb this pathology. A great deal of attention has been paid to glutathione, which is the brain's dominant antioxidant and plays a fundamental role in removing free radicals and other reactive oxygen species. Measurement of glutathione concentration in the brain in vivo can provide information on redox status and potential for oxidative stress to develop. Glutathione might also represent a marker to assess treatment response.

METHODS

This paper systematically reviews studies that assess glutathione concentration (measured using magnetic resonance spectroscopy) in various mental health conditions.

RESULTS

There is limited evidence showing altered brain glutathione concentration in mental disorders; the best evidence suggests glutathione is decreased in depression, but is not altered in bipolar disorder. The review then outlines the various methodological options for acquiring glutathione data using spectroscopy.

CONCLUSIONS

Analysis of the minimum effect size measurable in existing studies indicates that increased number of participants is required to measure subtle but possibly important differences and move the field forward.

Cerebrospinal fluid oxidative stress metabolites in patients with bipolar disorder and healthy controls: a longitudinal case-control study

Bipolar disorder (BD) is a mental disorder characterized by recurrent relapses of affective episodes, cognitive impairment, illness progression, and reduced life expectancy. Increased systemic oxidatively generated nucleoside damage have been found in some neurodegenerative disorders and in BD. As the first, this naturalistic prospective, longitudinal follow-up case-control study investigated cerebrospinal fluid (CSF) oxidative stress markers 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) that relate to RNA and DNA damage, respectively. Patients with BD (n = 86, 51% female) and gender-and-age-matched healthy control individuals (HC; n = 44, 44% female) were evaluated at baseline (T0), during (T1) and after a new affective episode (T2), if it occurred, and after a year (T3). Cerebrospinal and urine oxidative stress markers were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. CSF-8-oxoGuo was statistically significantly higher by 18% (p = 0.003) in BD versus HC at T0, and by 22% (p = 0) at T3. CSF-8-oxoGuo had increased by 15% (p = 0.042) from T0 to T3, and by 14% (p = 0.021) from T2 to T3 in patients, who experienced an episode during follow-up. CSF-8-oxodG had increased by 26% (p = 0.054) from T0 to T2 and decreased by 19% (p = 0.041) from T2 to T3 in patients, who experienced an episode during follow-up. CSF-8-oxoGuo did not show a statistically significant change in HC during the one-year follow-up. CSF and urine-8-oxoGuo levels correlated moderately. In conclusion, CSF oxidative stress marker of RNA damage 8-oxoGuo showed both state and trait dependence in BD and stability in HC. Central RNA damage may be a potential biomarker for BD.

Indoleamine-2,3-dioxygenase-1 is a molecular target for the protective activity of mood stabilizers against mania-like behavior induced by d-amphetamine

It is recognized that d-amphetamine (AMPH)-induced hyperactivity is thought to be a valid animal model of mania. In the present study, we investigated whether a proinflammatory oxidative gene indoleamine-2,3-dioxygenase (IDO) is involved in AMPH-induced mitochondrial burden, and whether mood stabilizers (i.e., lithium and valproate) modulate IDO to protect against AMPH-induced mania-like behaviors. AMPH-induced IDO-1 expression was significantly greater than IDO-2 expression in the prefrontal cortex of wild type mice. IDO-1 expression was more pronounced in the mitochondria than in the cytosol. AMPH treatment activated intra-mitochondrial Ca²⁺ accumulation and mitochondrial oxidative burden, while inhibited mitochondrial membrane potential and activity of the mitochondrial complex (I > II), mitochondrial glutathione peroxidase, and superoxide dismutase, indicating that mitochondrial burden might be contributable to mania-like behaviors induced by AMPH. The behaviors were significantly attenuated by lithium, valproate, or IDO-1 knockout, but not in IDO-2 knockout mice. Lithium, valproate administration, or IDO-1 knockout significantly attenuated mitochondrial burden. Neither lithium nor valproate produced additive effects above the protective effects observed in IDO-1 KO in mice. Collectively, our results suggest that mood stabilizers attenuate AMPH-induced mania-like behaviors via attenuation of IDO-1-dependent mitochondrial stress, highlighting IDO-1 as a novel molecular target for the protective potential of mood stabilizers.

Mitochondria, Metabolism, and Redox Mechanisms in Psychiatric Disorders

Significance: Our current knowledge of the pathophysiology and molecular mechanisms causing psychiatric disorders is modest, but genetic susceptibility and environmental factors are central to the etiology of these conditions. Autism, schizophrenia, bipolar disorder and major depressive disorder show genetic gene risk overlap and share symptoms and metabolic comorbidities. The identification of such common features may provide insights into the development of these disorders. Recent Advances: Multiple pieces of evidence suggest that brain energy metabolism, mitochondrial functions and redox balance are impaired to various degrees in psychiatric disorders. Since mitochondrial metabolism and redox signaling can integrate genetic and environmental environmental factors affecting the brain, it is possible that they are implicated in the etiology and progression of psychiatric disorders. Critical Issue: Evidence for direct links between cellular mitochondrial dysfunction and disease features are missing. Future Directions: A better understanding of the mitochondrial biology and its intracellular connections to the nuclear genome, the endoplasmic reticulum and signaling pathways, as well as its role in intercellular communication in the organism, is still needed. This review focuses on the findings that implicate mitochondrial dysfunction, the resultant metabolic changes and oxidative stress as important etiological factors in the context of psychiatric disorders. We also propose a model where specific pathophysiologies of psychiatric disorders depend on circuit-specific impairments of mitochondrial dysfunction and redox signaling at specific developmental stages.

Is Lithium a Micronutrient? From Biological Activity and Epidemiological Observation to Food Fortification

Lithium compounds have been widely used in psychopharmacology, particularly in the treatment of bipolar disorder. Their normothymic and neuroprotective properties when used at high doses have been well established. However, a number of observations suggest that environmentally relevant lithium doses may also exert beneficial health effects, leading to a decrease in the rate of suicides and levels of violence. Despite the fact that this element is not officially considered to be a micronutrient, some authors have suggested provisional recommended intakes set at 1000 μg/day for a 70-kg adult (14.3 μg/kg body weight). The present paper reviews the biological action of lithium, its bioavailability and metabolism, and content in different foodstuffs and water. It also assesses epidemiological data on potential correlations between lithium intake and suicide rate as well as examines the concept of fortifying food with this element as a strategy in the primary prevention of mood disorders and pre-suicidal syndrome.

Antioxidant defense in schizophrenia and bipolar disorder: A meta-analysis of MRS studies of anterior cingulate glutathione

BACKGROUND

Glutathione [GSH] is a major intracellular antioxidant that disposes peroxides and protects neurons and glial cells from oxidative stress. In both schizophrenia and bipolar disorder, atypical levels of GSH have been demonstrated, particularly in the anterior cingulate cortex (ACC), though no consistent results have emerged due to limitations in sample size. Our objective was to evaluate if GSH levels in the ACC are abnormal in these 2 disorder, when compared to healthy controls.

METHODS

We reviewed all 1H-MRS studies reporting GSH values for patients satisfying DSM or ICD based criteria for (1) the psychotic disorders - schizophrenia or schizoaffective disorder or (2) bipolar disorder in comparison to a healthy controls (HC) group in the Anterior Cingulate Cortex (ACC) published until June 2018. A random-effects model was used to calculate the pooled effect size. A meta-regression analysis of moderator variables was also undertaken.

RESULTS

The literature search identified 18 studies with a total sample size of 581 controls, 578 patients with schizophrenia or bipolar disorder. There is a small but significant reduction in ACC GSH in patients with schizophrenia compared to HC (N = 13; RFX SMD =0.26; 95% CI [0.07 to 0.44]; p = 0.008; heterogeneity p = 0.11). There is a significant increase in the ACC GSH concentration in bipolar disorder compared to HC (N = 6; RFX SMD = -0.28, 95% CI [-0.09 to -0.47]; p = 0.003; heterogeneity p = 0.95).

CONCLUSIONS

We report a small, but significant reduction in GSH concentration in the ACC in schizophrenia, and a similar sized increase in bipolar disorder. A notable limitation is the lack of sufficient data to examine the moderating effect of the symptom profile. Schizophrenia and bipolar disorder have notably different patterns of redox abnormalities in the ACC. Reduced ACC GSH may confer a schizophrenia-like clinical phenotype, while an excess favouring a bipolar disorder-like profile.

Modulation of Hippocampal Antioxidant Defense System in Chronically Stressed Rats by Lithium

This study examined the effects of lithium on gene expression and activity of the antioxidant enzymes copper zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in the hippocampus of chronically stressed rats. In addition, we examined the effects of lithium on anxiety behaviors, hippocampal concentrations of dopamine (DA) and malondialdehyde (MDA), protein levels of brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT), as well as activity of monoamine oxidase (MAO) in chronically stressed rats. The investigated parameters were quantified by real-time RT-PCR, Western blot analyses, and assays of enzyme activities. We found that lithium did not change gene expression of SOD1, CAT, GPx, and GR but decreased gene expression of SOD2 in chronically stressed rats. A very important result in this study was that lithium treatment decreased the enzyme activities of SOD1 and SOD2 but increased the enzyme activities of GPx and GR in stress condition, which indicates the control of redox balance. The reduced concentration of MDA confirms this. In addition, we found that lithium treatment decreased high protein levels of BDNF and DAT in chronically stressed rats to the level found in unstressed animals. Also, lithium treatment increased the expression of TH but decreased the enzyme activity of MAO B, which contributed to the increase of hippocampal concentration of DA in chronically stressed rats to the level of unstressed animals. Finally, lithium treatment in animals exposed to chronic stress increased the time spent in open arms. Lithium-induced modulation of hippocampal antioxidant status and attenuation of oxidative stress stabilized behavior in animals with high anxiety index. In addition, reduced oxidative stress was followed by the changes of both turnover of DA and levels of BDNF protein in chronically stressed rats treated with lithium. These findings may be important in preclinical research of the effects of lithium on oxidative stress level in pathological conditions.

The Relationship between the Number of Manic Episodes and Oxidative Stress Indicators in Bipolar Disorder

OBJECTIVE

Bipolar disorder (BD) is a chronic mood disorder characterized by recurrent episodes that has a lifetime prevalence of 0.4- 5.5%. The neurochemical mechanism of BD is not fully understood. Oxidative stress in neurons causes lipid peroxidation in proteins associated with neuronal membranes and intracellular enzymes and it may lead to dysfunction in neurotransmitter reuptake and enzyme activities. These pathological processes are thought to occur in brain regions associated with affective functions and emotions in BD. The relationship between the number of manic episodes and total oxidant-antioxidant capacity was investigated in this study.

METHODS

Eighty-two BD patients hospitalized due to manic symptoms and with no episodes of depression were enrolled in the study. Thirty of the 82 patients had had their first episode of mania, and the other 52 patients had had two or more manic episodes. The control group included 45 socio-demographically matched healthy individuals. Serum total antioxidant capacity (TAC) and total oxidant capacity (TOC) measurements of the participants were performed. The oxidative stress index (OSI) was calculated by TOC/TAC.

RESULTS

There were no significant differences in OSI scores between BD patients with first-episode mania and BD patients with more than one manic episode. However, OSI scores in both groups were significantly higher than in the control group. TOC levels of BD patients with first-episode mania were found to be significantly higher than TOC levels of BD patients with more than one manic episode and healthy controls. There were no significant differences in TAC levels between BD patients with first-episode mania and BD patients with more than one manic episode. TAC levels in both groups were significantly higher than in the control group.

CONCLUSION

Significant changes in oxidative stress indicators were observed in this study, confirming previous studies. Increased levels of oxidants were shown with increased disease severity rather than with the number of manic episodes. Systematic studies, including of each period of the disorder, are needed for using the findings indicating deterioration of oxidative parameters.

Oxidatively-induced DNA damage and base excision repair in euthymic patients with bipolar disorder

Oxidatively-induced DNA damage has previously been associated with bipolar disorder. More recently, impairments in DNA repair mechanisms have also been reported. We aimed to investigate oxidatively-induced DNA lesions and expression of DNA glycosylases involved in base excision repair in euthymic patients with bipolar disorder compared to healthy individuals. DNA base lesions including both base and nucleoside modifications were measured using gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry with isotope-dilution in DNA samples isolated from leukocytes of euthymic patients with bipolar disorder (n = 32) and healthy individuals (n = 51). The expression of DNA repair enzymes OGG1 and NEIL1 were measured using quantitative real-time polymerase chain reaction. The levels of malondialdehyde were measured using high performance liquid chromatography. Seven DNA base lesions in DNA of leukocytes of patients and healthy individuals were identified and quantified. Three of them had significantly elevated levels in bipolar patients when compared to healthy individuals. No elevation of lipid peroxidation marker malondialdehyde was observed. The level of OGG1 expression was significantly reduced in bipolar patients compared to healthy individuals, whereas the two groups exhibited similar levels of NEIL1 expression. Our results suggest that oxidatively-induced DNA damage occurs and base excision repair capacity may be decreased in bipolar patients when compared to healthy individuals. Measurement of oxidatively-induced DNA base lesions and the expression of DNA repair enzymes may be of great importance for large scale basic research and clinical studies of bipolar disorder.

An investigation into closed-loop treatment of neurological disorders based on sensing mitochondrial dysfunction

Dynamic feedback based closed-loop medical devices offer a number of advantages for treatment of heterogeneous neurological conditions. Closed-loop devices integrate a level of neurobiological feedback, which allows for real-time adjustments to be made with the overarching aim of improving treatment efficacy and minimizing risks for adverse events. One target which has not been extensively explored as a potential feedback component in closed-loop therapies is mitochondrial function. Several neurodegenerative and psychiatric disorders including Parkinson's disease, Major Depressive disorder and Bipolar disorder have been linked to perturbations in the mitochondrial respiratory chain. This paper investigates the potential to monitor this mitochondrial function as a method of feedback for closed-loop neuromodulation treatments. A generic model of the closed-loop treatment is developed to describe the high-level functions of any system designed to control neural function based on mitochondrial response to stimulation, simplifying comparison and future meta-analysis. This model has four key functional components including: a sensor, signal manipulator, controller and effector. Each of these components are described and several potential technologies for each are investigated. While some of these candidate technologies are quite mature, there are still technological gaps remaining. The field of closed-loop medical devices is rapidly evolving, and whilst there is a lot of interest in this area, widespread adoption has not yet been achieved due to several remaining technological hurdles. However, the significant therapeutic benefits offered by this technology mean that this will be an active area for research for years to come.

The Energy Metabolism Dysfunction in Psychiatric Disorders Postmortem Brains: Focus on Proteomic Evidence

Psychiatric disorders represent a great medical and social challenge and people suffering from these conditions face many impairments regarding personal and professional life. In addition, a mental disorder will manifest itself in approximately one quarter of the world's population at some period of their life. Dysfunction in energy metabolism is one of the most consistent scientific findings associated with these disorders. With this is mind, this review compiled data on disturbances in energy metabolism found by proteomic analyses of postmortem brains collected from patients affected by the most prevalent psychiatric disorders: schizophrenia (SCZ), bipolar disorder (BPD), and major depressive disorder (MDD). We searched in the PubMed database to gather the studies and compiled all the differentially expressed proteins reported in each work. SCZ studies revealed 92 differentially expressed proteins related to energy metabolism, while 95 proteins were discovered in BPD, and 41 proteins in MDD. With the compiled data, it was possible to determine which proteins related to energy metabolism were found to be altered in all the disorders as well as which ones were altered exclusively in one of them. In conclusion, the information gathered in this work could contribute to a better understanding of the impaired metabolic mechanisms and hopefully bring insights into the underlying neuropathology of psychiatric disorders.

Biochemical and genetic predictors and correlates of response to lamotrigine and folic acid in bipolar depression: Analysis of the CEQUEL clinical trial

OBJECTIVES

CEQUEL (Comparative Evaluation of QUEtiapine plus Lamotrigine combination versus quetiapine monotherapy [and folic acid versus placebo] in bipolar depression) was a double-blind, randomized, placebo-controlled, parallel group, 2×2 factorial trial that examined the effect of adding lamotrigine and/or folic acid (FA) to quetiapine in bipolar depression. Lamotrigine improved depression, but its effectiveness was reduced by FA. We investigated the baseline predictors and correlates of clinical response, and the possible basis of the interaction.

METHODS

The main outcome was change in depressive symptoms at 12 weeks, measured using the Quick Inventory for Depressive Symptoms-self report version 16 (QIDS-SR16). We examined the relationship between symptoms and lamotrigine levels, and biochemical measures of one-carbon metabolism and functional polymorphisms in catechol-O-methyltransferase (COMT), methylene tetrahydrofolate reductase (MTHFR) and folate hydrolase 1 (FOLH1).

RESULTS

Lamotrigine levels were unaffected by FA and did not differ between those participants who achieved remission and those with persisting symptoms. When participants with subtherapeutic serum levels were excluded, there was a main effect of lamotrigine on the main outcome, although this remained limited to those randomized to FA placebo. None of the biochemical measures correlated with clinical outcome. The negative impact of FA on lamotrigine response was limited to COMT Met carriers. FOLH1 and MTHFR had no effect.

CONCLUSIONS

Our results clarify that FA's inhibition of lamotrigine's efficacy is not a pharmacokinetic effect, and that low serum lamotrigine levels contributed to lamotrigine's lack of a main effect at 12 weeks. We were unable to explain the lamotrigine-FA interaction, but our finding that it is modulated by the COMT genotype provides a starting point for follow-on neurobiological investigations. More broadly, our results highlight the value of including biochemical and genetic indices in randomized clinical trials.

Molecular Mechanisms of Bipolar Disorder: Progress Made and Future Challenges

Bipolar disorder (BD) is a chronic and progressive psychiatric illness characterized by mood oscillations, with episodes of mania and depression. The impact of BD on patients can be devastating, with up to 15% of patients committing suicide. This disorder is associated with psychiatric and medical comorbidities and patients with a high risk of drug abuse, metabolic and endocrine disorders and vascular disease. Current knowledge of the pathophysiology and molecular mechanisms causing BD is still modest. With no clear biological markers available, early diagnosis is a great challenge to clinicians without previous knowledge of the longitudinal progress of illness. Moreover, despite recommendations from evidence-based guidelines, polypharmacy is still common in clinical treatment of BD, reflecting the gap between research and clinical practice. A major challenge in BD is the development of effective drugs with low toxicity for the patients. In this review article, we focus on the progress made and future challenges we face in determining the pathophysiology and molecular pathways involved in BD, such as circadian and metabolic perturbations, mitochondrial and endoplasmic reticulum (ER) dysfunction, autophagy and glutamatergic neurotransmission; which may lead to the development of new drugs.

Oxidative Stress Implications in the Affective Disorders: Main Biomarkers, Animal Models Relevance, Genetic Perspectives, and Antioxidant Approaches

The correlation between the affective disorders and the almost ubiquitous pathological oxidative stress can be described in a multifactorial way, as an important mechanism of central nervous system impairment. Whether the obvious changes which occur in oxidative balance of the affective disorders are a part of the constitutive mechanism or a collateral effect yet remains as an interesting question. However it is now clear that oxidative stress is a component of these disorders, being characterized by different aspects in a disease-dependent manner. Still, there are a lot of controversies regarding the relevance of the oxidative stress status in most of the affective disorders and despite the fact that most of the studies are showing that the affective disorders development can be correlated to increased oxidative levels, there are various studies stating that oxidative stress is not linked with the mood changing tendencies. Thus, in this minireview we decided to describe the way in which oxidative stress is involved in the affective disorders development, by focusing on the main oxidative stress markers that could be used mechanistically and therapeutically in these deficiencies, the genetic perspectives, some antioxidant approaches, and the relevance of some animal models studies in this context.

Mitochondrial dysfunction and lipid peroxidation in rat frontal cortex by chronic NMDA administration can be partially prevented by lithium treatment

Chronic N-methyl-d-aspartate (NMDA) administration to rats may be a model to investigate excitotoxicity mediated by glutamatergic hyperactivity, and lithium has been reported to be neuroprotective. We hypothesized that glutamatergic hyperactivity in chronic NMDA injected rats would cause mitochondrial dysfunction and lipid peroxidation in the brain, and that chronic lithium treatment would ameliorate some of these NMDA-induced alterations. Rats treated with lithium for 6 weeks were injected i.p. 25 mg/kg NMDA on a daily basis for the last 21 days of lithium treatment. Brain was removed and frontal cortex was analyzed. Chronic NMDA decreased brain levels of mitochondrial complex I and III, and increased levels of the lipid oxidation products, 8-isoprostane and 4-hydroxynonenal, compared with non-NMDA injected rats. Lithium treatment prevented the NMDA-induced increments in 8-isoprostane and 4-hydroxynonenal. Our findings suggest that increased chronic activation of NMDA receptors can induce alterations in electron transport chain complexes I and III and in lipid peroxidation in brain. The NMDA-induced changes may contribute to glutamate-mediated excitotoxicity, which plays a role in brain diseases such as bipolar disorder. Lithium treatment prevented changes in 8-isoprostane and 4-hydroxynonenal, which may contribute to lithium's reported neuroprotective effect and efficacy in bipolar disorder.

Nod-like receptor pyrin containing 3 (NLRP3) in the post-mortem frontal cortex from patients with bipolar disorder: A potential mediator between mitochondria and immune-activation

Mitochondrial complex I dysfunction, oxidative stress and immune-activation are consistently reported in bipolar disorder (BD). Mitochondrial production of reactive oxygen species was recently linked to activation of an inflammatory redox sensor, the nod-like receptor family pyrin domain-containing 3 (NLRP3). Upon its activation, NLRP3 recruits apoptosis-associated speck-like protein (ASC) and caspase-1 to form the NLRP3-inflammasome, activating IL-1β. This study aimed to examine if immune-activation may be a downstream target of complex I dysfunction through the NLRP3-inflammasome in BD. Post-mortem frontal cortex from patients with BD (N = 9), schizophrenia (N = 10), and non-psychiatric controls (N = 9) were donated from the Harvard Brain Tissue Resource Center. Levels of NLRP3, ASC and caspase-1 were measured by western blotting, ELISA and Luminex. While we found no effects of age, sex or post-mortem delay, lower levels of complex I (F2,25 = 3.46, p < 0.05) and NDUFS7, a subunit of complex I (F2,25 = 4.13, p < 0.05), were found in patients with BD. Mitochondrial NLRP3 (F2,25 = 3.86, p < 0.05) and ASC (F2,25 = 4.61, p < 0.05) levels were higher in patients with BD. However, levels of caspase 1 (F2,25 = 4.13, p < 0.05 for both), IL-1β (F2,25 = 7.05, p < 0.01), IL-6 (F2,25 = 5.48, p < 0.05), TNFα (F2,25 = 7.14, p < 0.01) and IL-10 (F2,25 = 5.02, p < 0.05) were increased in both BD and schizophrenia. These findings suggest that immune-activation in the frontal cortex may occur both in patients with BD and schizophrenia, while complex I dysfunction and NLRP3-inflammasome activation may be more specific to BD.

Exploring the possible link between MeCP2 and oxidative stress in Rett syndrome

Rett syndrome (RTT, MIM 312750) is a rare and orphan progressive neurodevelopmental disorder affecting girls almost exclusively, with a frequency of 1/15,000 live births of girls. The disease is characterized by a period of 6 to 18 months of apparently normal neurodevelopment, followed by early neurological regression, with a progressive loss of acquired cognitive, social, and motor skills. RTT is known to be caused in 95% of the cases by sporadic de novo loss-of-function mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene encoding methyl-CpG binding protein 2 (MeCP2), a nuclear protein able to regulate gene expression. Despite almost two decades of research into the functions and role of MeCP2, little is known about the mechanisms leading from MECP2 mutation to the disease. Oxidative stress (OS) is involved in the pathogenic mechanisms of several neurodevelopmental and neurodegenerative disorders, although in many cases it is not clear whether OS is a cause or a consequence of the pathology. Fairly recently, the presence of a systemic OS has been demonstrated in RTT patients with a strong correlation with the patients' clinical status. The link between MECP2 mutation and the redox imbalance found in RTT is not clear. Animal studies have suggested a possible direct correlation between Mecp2 mutation and increased OS levels. In addition, the restoration of Mecp2 function in astrocytes significantly improves the developmental outcome of Mecp2-null mice and reexpression of Mecp2 gene in the brain of null mice restored oxidative damage, suggesting that Mecp2 loss of function can be involved in oxidative brain damage. Starting from the evidence that oxidative damage in the brain of Mecp2-null mice precedes the onset of symptoms, we evaluated whether, based on the current literature, the dysfunctions described in RTT could be a consequence or, in contrast, could be caused by OS. We also analyzed whether therapies that at least partially treated some RTT symptoms can play a role in defense against OS. At this stage we can propose that OS could be one of the main causes of the dysfunctions observed in RTT. In addition, the major part of the therapies recommended to alleviate RTT symptoms have been shown to interfere with oxidative homeostasis, suggesting that MeCP2 could somehow be involved in the protection of the brain from OS.

Potential application of lithium in Parkinson's and other neurodegenerative diseases

Lithium, the long-standing hallmark treatment for bipolar disorder, has recently been identified as a potential neuroprotective agent in neurodegeneration. Here we focus on introducing numerous in vitro and in vivo studies that have shown lithium treatment to be efficacious in reducing oxidative stress and inflammation, increasing autophagy, inhibiting apoptosis, and decreasing the accumulation of α-synulcein, with an emphasis on Parkinson's disease. A number of biological pathways have been shown to be involved in causing these neuroprotective effects. The inhibition of GSK-3β has been the mechanism most studied; however, other modes of action include the regulation of apoptotic proteins and glutamate excitotoxicity as well as down-regulation of calpain. This review provides a framework of the neuroprotective effects of lithium in neurodegenerative diseases and the putative mechanisms by which lithium provides the protection. Lithium-only treatment may not be a suitable therapeutic option for neurodegenerative diseases due to inconsistent efficacy and potential side-effects, however, the use of low dose lithium in combination with other potential or existing therapeutic compounds may be a promising approach to reduce symptoms and disease progression in neurodegenerative diseases.

Valproic Acid for Treatment of Hyperactive or Mixed Delirium: Rationale and Literature Review

BACKGROUND

Delirium is the most often encountered psychiatric diagnosis in the general hospital, with an incidence of up to 82% in the intensive care unit setting and with significant detrimental effects on patients' morbidity and mortality. Antipsychotics are often considered the first-line pharmacological treatment of delirium, but their use may be limited by lack of efficacy, existing contraindications (e.g., prolonged QTc intervals), or resulting side effects (e.g., akathisia). Valproic acid (VPA) is a potential alternative or adjunct treatment. It has multiple mechanisms of action, including effects on neurotransmitter modulation, neuroinflammation, oxidative stress, and transcription, all of which are implicated in the pathophysiology of delirium. Yet, data on the use of this agent in delirium are limited.

OBJECTIVE/METHODS

In this article, we discuss postulated mechanisms of VPA action that provide a theoretical basis for its use in the treatment of hyperactive and mixed type delirium, based on the known and theorized pathophysiology of delirium. We also discuss potential side effects and considerations with use of VPA.

CONCLUSIONS

VPA has multiple modulatory effects on neurotransmitter systems, inflammation, oxidative stress, and transcriptional changes implicated in pathophysiology of delirium. When carefully chosen, VPA can be an effective and well-tolerated treatment option for the management of hyperactive and mixed type delirium. Randomized controlled trials are needed to establish tolerability and efficacy of VPA for treatment of delirium.

GBR 12909 administration as an animal model of bipolar mania: time course of behavioral, brain oxidative alterations and effect of mood stabilizing drugs

Polymorphisms in the human dopamine transporter (DAT) are associated with bipolar endophenotype. Based on this, the acute inhibition of DAT using GBR12909 causes behavioral alterations that are prevented by valproate (VAL), being related to a mania-like model. Herein our first aim was to analyze behavioral and brain oxidative alterations during a 24 h period post-GBR12909 to better characterize this model. Our second aim was to determine the preventive effects of lithium (Li) or VAL 2 h post-GBR12909. For this, adult male mice received GBR12909 or saline being evaluated at 2, 4, 8, 12 or 24 h post-administration. Hyperlocomotion, levels of reduced glutathione (GSH) and lipid peroxidation in brain areas were assessed at all these time-points. GBR12909 caused hyperlocomotion at 2 and 24 h. Rearing behavior increased only at 2 h. GSH levels decreased in the hippocampus and striatum at the time points of 2, 4, 8 and 12 h. Increased lipid peroxidation was detected at the time-points of 2 and 12 h in all brain areas studied. At the time-point of 2 h post-GBR12909 Li prevented the hyperlocomotion and rearing alterations, while VAL prevented only rearing alterations. Both drugs prevented pro-oxidative changes. In conclusion, we observed that the main behavioral and oxidative alterations took place at the time-period of 2 h post-GBR12909, what points to this time-period as the best for the assessment of alterations in this model. Furthermore, the present study expands the predictive validity of the model by the determination of the preventive effects of Li.

Oxidative stress in bipolar and schizophrenia patients

Oxidative stress has an important place in studies investigating the pathophysiology of psychiatric diseases. In spite of this fact, longitudinal studies are required to clarify the subject. Therefore, in this study, we examined lipid peroxidation, protein oxidation, total oxidized guanine species, superoxide dismutase (SOD) and total glutathione (GSH) levels in blood collected from adult bipolar patients (n=18) during manic and euthymic episodes, schizophrenic patients (n=18) during acute psychotic attack and remission phases and the control group (n=18). There was a significant increase in the level of lipid peroxidation in the bipolar disorder manic episode group (BD-ME) compared to control group. The level of protein oxidation was significantly higher in the schizophrenia acute psychotic attack group (SZ-APA) compared to the control group. The level of total oxidized guanine species was statistically higher in all psychiatric groups compared to the control group. There was no significant difference among the groups with regard to SOD and GSH. Consequently, we believe that lipid peroxidation may be effective in the pathogenesis of bipolar patients; that protein oxidation may be of importance in the pathogenesis of schizophrenia and that total oxidized guanine species may be crucial in the pathogeneses of both psychiatric disorders.

Alcohol use in bipolar disorder: A neurobiological model to help predict susceptibility, select treatments and attenuate cortical insult

In a series of neurophysiological and neuroimaging studies we investigated the neurobiology related to alcohol use in young people with bipolar disorder. Impairments were identified across frontal and temporal representations of event-related potential and proton magnetic resonance spectroscopy markers; mismatch negativity and in vivo glutathione, respectively. We propose these findings reflect impairments in the N-methyl-D-aspartate receptor and antioxidant capacity. This review seeks to place these findings within the broader literature in the context of two propositions: 1. Pathophysiological impairments in N-methyl-D-aspartate receptor functioning in bipolar disorder contribute to susceptibility toward developing alcohol problems. 2. Alcohol aggravates bipolar disorder neuroprogression via oxidative stress. A neurobiological model that incorporates these propositions is presented, with a focus on the potential for N-methyl-D-aspartate receptor antagonism and glutathione augmentation as potential adjunctive pharmacotherapies to treat the comorbidity. While this review highlights the importance of alcohol monitoring and reduction strategies in the treatment of bipolar disorder, the clinical impact of the proposed model remains limited by the lack of controlled trials of novel pharmacological interventions.

The many roads to mitochondrial dysfunction in neuroimmune and neuropsychiatric disorders

BACKGROUND

Mitochondrial dysfunction and defects in oxidative metabolism are a characteristic feature of many chronic illnesses not currently classified as mitochondrial diseases. Examples of such illnesses include bipolar disorder, multiple sclerosis, Parkinson's disease, schizophrenia, depression, autism, and chronic fatigue syndrome.

DISCUSSION

While the majority of patients with multiple sclerosis appear to have widespread mitochondrial dysfunction and impaired ATP production, the findings in patients diagnosed with Parkinson's disease, autism, depression, bipolar disorder schizophrenia and chronic fatigue syndrome are less consistent, likely reflecting the fact that these diagnoses do not represent a disease with a unitary pathogenesis and pathophysiology. However, investigations have revealed the presence of chronic oxidative stress to be an almost invariant finding in study cohorts of patients afforded each diagnosis. This state is characterized by elevated reactive oxygen and nitrogen species and/or reduced levels of glutathione, and goes hand in hand with chronic systemic inflammation with elevated levels of pro-inflammatory cytokines.

SUMMARY

This paper details mechanisms by which elevated levels of reactive oxygen and nitrogen species together with elevated pro-inflammatory cytokines could conspire to pave a major road to the development of mitochondrial dysfunction and impaired oxidative metabolism seen in many patients diagnosed with these disorders.

Oxidative stress in older patients with bipolar disorder

OBJECTIVE

Increases in oxidative stress have been consistently reported in younger patients with bipolar disorder (BD) in postmortem brain and blood samples studies. Changes in oxidative stress are also associated with the natural aging process. Thus, the investigation of oxidative stress across the life span of patients with BD is crucial.

METHODS

We compared the levels of oxidative damage to proteins and lipids in plasma from 110 euthymic older patients with BD I or II (mean±SD age: 63.9±9.7 years) and 75 older healthy individuals (66.0±9.6 years). To assess protein oxidation, we measured the plasma levels of protein carbonyl (PC) and 3-nitrotyrosine (3-NT) using the ELISA technique. To assess lipid peroxidation, we measured plasma levels of lipid hydroperoxide (LPH) and 4-hydroxynonenal (4-HNE) using spectrophotometric assays.

RESULTS

LPH levels were higher in patients than in the comparison healthy individuals, whereas there were no significant differences for PC, 3-NT, and 4-HNE between the two groups.

CONCLUSIONS

The increased levels of an early component of the peroxidation chain (LPH) in euthymic older patients with BD support the hypothesis of a persistent effect of reactive species of oxygen in patients with BD into late life.

Changes in the anti-oxidant system in adult epilepsy patients receiving anti-epileptic drugs

Anti-epileptic drugs (AEDs) have been widely used in patients with epilepsy. This study evaluated the adverse effects of two commonly prescribed AED monotherapies, carbamazepine (CBZ) and valproic acid (VPA). The aim of this study was to evaluate the influence of these anti-epileptic drugs on paraoxonase-1 (PON-1), glutathione S-transferase (GST) and acetyl cholinesterase (AChE) activities in the serum of adult patients with epilepsy. Of the 56 epileptic adults, 28 were given valproate, and the remaining 28 were given carbamazepine. Glutathione (GSH) levels in epilepsy patients receiving anti-epileptic drug treatment were insignificantly higher compared with controls. GST activity in epilepsy patients receiving anti-epileptic drug treatment was insignificantly lower compared with controls. PON1 and AChE activity in epilepsy patients receiving anti-epileptic drug treatment was significantly lower compared with controls. PON1 and AChE activities in the serum of patients treated with carbamazepine monotherapy were lower than in patients treated with valproic acid monotherapy.

Synergistic effects of GSK-3β and HDAC inhibitors in intracerebroventricular streptozotocin-induced cognitive deficits in rats

Recent studies suggest the importance of combined treatment of glycogen synthase kinase-3β (GSK-3β) and histone deacetylase (HDAC) inhibition in various in vitro and in vivo models of neurological diseases. Lithium chloride (LiCl) and valproate (VPA), two well-known mood stabilizers, have been reported to act through GSK-3β and HDAC inhibition, respectively. The present study was designed to investigate the potential of low-dose combination of LiCl and VPA in intracerebroventricular streptozotocin (ICV-STZ)-induced cognitive deficits in rats. STZ was injected twice (3 mg/kg ICV) on alternate days (day 1 and day 3) in rats. The ICV-STZ-treated rats received LiCl (60 mg/kg, i.p.), VPA (200 mg/kg, i.p.), and combination of both LiCl (60 mg/kg, i.p.) and VPA (200 mg/kg, i.p.) drugs for a period of 3 weeks. The ICV-STZ administration results in significant memory impairment, elevated oxidative-nitrosative stress, and reduced brain-derived neurotrophic factor (BDNF) levels. Using a battery of behavioral and biochemical tests, we observed that co-treatment of both drugs showed synergistic effect in improving the spatial learning and memory impairment as well as significantly attenuated the oxidative stress markers in STZ-treated rats as compared to either drug alone. Moreover, the combination of both drugs reversed the hyperinsulinemic brain condition and improved the BDNF levels in STZ-treated rats. Based upon these results, it could be suggested that a low-dose combination of LiCl and VPA produces synergistic and more consistent neuroprotective effects in ICV-STZ-induced cognitive deficits in rats.

Vitamin U, a novel free radical scavenger, prevents lens injury in rats administered with valproic acid

Valproic acid (2-propyl-pentanoic acid, VPA) is the most widely prescribed antiepileptic drug due to its ability to treat a broad spectrum of seizure types. VPA exhibits various side effects such as organ toxicity, teratogenicity, and visual disturbances. S-Methylmethioninesulfonium is a derivative of the amino acid methionine and it is widely referred to as vitamin U (Vit U). This study was aimed to investigate the effects of Vit U on lens damage parameters of rats exposed to VPA. Female Sprague Dawley rats were divided into four groups. Group I comprised control animals. Group II included control rats supplemented with Vit U (50 mg/kg/day) for 15 days. Group III was given only VPA (500 mg/kg/day) for 15 days. Group IV was given VPA + Vit U (in same dose and time). Vit U was given to rats by gavage and VPA was given intraperitoneally. On the 16th day of experiment, all the animals which were fasted overnight were killed. Lens was taken from animals, homogenized in 0.9% saline to make up to 10% (w/v) homogenate. The homogenates were used for protein, glutathione, lipid peroxidation levels, and antioxidant enzymes activities. Lens lipid peroxidation levels and aldose reductase and sorbitol dehydrogenase activities were increased in VPA group. On the other hand, glutathione levels, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione- S-transferase, and paraoxonase activities were decreased in VPA groups. Treatment with Vit U reversed these effects. This study showed that Vit U exerted antioxidant properties and may prevent lens damage caused by VPA.

Lithium reduces the effects of rotenone-induced complex I dysfunction on DNA methylation and hydroxymethylation in rat cortical primary neurons

RATIONALE

Mitochondrial complex I dysfunction and alterations in DNA methylation levels are consistently reported in bipolar disorder (BD) and are regulated by lithium. One of the mechanisms by which lithium may exert its effects in BD is by improving mitochondrial complex I function. Therefore, we examined whether complex I dysfunction induces methylation and hydroxymethylation of DNA and whether lithium alters these effects in rat primary cortical neurons.

METHODS

Rotenone was used to induce mitochondrial complex I dysfunction. Cell viability was measured by MTT assay, and ATP levels were assessed by Cell-Titer-Glo. Complex I activity was measured using an ELISA-based assay. Apoptosis, DNA methylation, and hydroxymethylation levels were measured by immunocytochemistry.

RESULTS

Rotenone decreased complex I activity and ATP production, but increased cell death and apoptosis. Rotenone treatment increased levels of 5-methylcytosine (5mc) and hydroxymethylcytosine (5hmc), suggesting a possible association between complex I dysfunction and DNA alterations. Lithium prevented rotenone-induced changes in mitochondrial complex I function, cell death and changes to DNA methylation and hydroxymethylation.

CONCLUSIONS

These findings suggest that decreased mitochondrial complex I activity may increase DNA methylation and hydroxymethylation in rat primary cortical neurons and that lithium may prevent these effects.