Antioxidant enzyme activities and oxidative stress in affective disorders

Antioxidants as potential therapeutics for neuropsychiatric disorders

Oxidative stress has been implicated in the pathophysiology of many neuropsychiatric disorders such as schizophrenia, bipolar disorder, major depression etc. Both genetic and non-genetic factors have been found to cause increased cellular levels of reactive oxygen species beyond the capacity of antioxidant defense mechanism in patients of psychiatric disorders. These factors trigger oxidative cellular damage to lipids, proteins and DNA, leading to abnormal neural growth and differentiation. Therefore, novel therapeutic strategies such as supplementation with antioxidants can be effective for long-term treatment management of neuropsychiatric disorders. The use of antioxidants and PUFAs as supplements in the treatment of neuropsychiatric disorders has provided some promising results. At the same time, one should be cautious with the use of antioxidants since excessive antioxidants could dangerously interfere with some of the protective functions of reactive oxygen species. The present article will give an overview of the potential strategies and outcomes of using antioxidants as therapeutics in psychiatric disorders.

The role of inflammatory cytokines on the aetiopathogenesis of depression

OBJECTIVE

The primary focus of this review is to provide an overview of the role of inflammation in the development of depression. The article will describe how inflammatory cytokines contribute to depression via action on three major pathways in the brain: the neuroendocrine; neurotransmitter depletion; and neuroprogression pathways.

METHODS

An online literature search was carried out in July 2012. Original articles and reviews were selected if they discussed the role of inflammation on the development of depression.

RESULTS

There is a large body of current research on the role of inflammatory cytokines on the development of depression. Cytokines have been found to interact with different pathways in the brain, and may contribute to the development of depression. Cytokines cause hypercortisolaemia by dysregulation of the hypothalamic-pituitary-adrenal axis directly by activating it and indirectly by modifying glucocorticoid receptor sensitivity to cortisol leading to cortisol hypersecretion. Cytokines deplete central synaptic serotonin levels by reducing its synthesis and increasing its reuptake. They may also deplete neurotrophic factors which are believed to play a neuroprotective role against depression. Cytokines activate cellular cascades that cause excitotoxicity and apoptosis and inhibit neurogenesis in the hippocampus.

CONCLUSION

There is a growing body of correlative studies that suggest inflammatory cytokines may be a central factor that can affect multiple neuronal pathways and have an additive effect on the development of depression. However, the fact that not all people with inflammatory conditions suffer from depression suggests that depression is not purely a result of elevated inflammatory cytokines. Depression may be a result of a complex pathology that remains an area of growing interest and importance.

Increased autoimmune responses against auto-epitopes modified by oxidative and nitrosative damage in depression: implications for the pathways to chronic depression and neuroprogression

OBJECTIVE

There is evidence that major depression is characterized by oxidative and nitrosative stress (O&NS). The aim of this study is to examine IgM-mediated autoimmune responses against a variety of modified neo-epitopes formed by O&NS damage to self-epitopes in chronic depression.

METHODS

Serum IgM antibodies directed against conjugated oleic and azelaic acid, malondialdehyde (MDA), phosphatidyl inositol (Pi), and conjugated nitric-oxide (NO) adducts, i.e., NO-tryptophan, NO-tyrosine, NO-arginine, and NO-cysteinyl, were determined in 33 healthy controls and 74 depressed patients subdivided into 28 patients with chronic (duration >2 year) and 46 without chronic depression.

RESULTS

Serum IgM levels against all neoepitopes were significantly higher in depressed patients than in healthy controls. Moreover, the IgM levels were significantly higher, except Pi, in chronically depressed patients than in non-chronically depressed patients.

CONCLUSIONS

Depression is characterized by IgM-related autoimmune responses directed against neo-epitopes that are normally hidden from the immune system but that became immunogenic secondary to damage by O&NS. The results show that the generation of neoantigenic determinants that lead to (auto)immune responses is strongly associated with chronic depression.

DISCUSSION

The damage caused by O&NS to auto-epitopes and the consequent formation of O&NS modified neoantigenic determinants may increase the risk to develop depression and in particular chronic depression through transition to autoimmune reactions. This has implications for understanding the immuno-inflammatory and oxidative-autoimmune pathways that lead to chronic depression and neuroprogression in that illness.

Obesity and mental illness: implications for cognitive functioning

A priority research and clinical agenda is to identify determinants of cognitive impairment in individuals with neuropsychiatric disorders (NPD). The bidirectional association between NPD and cognitive performance has been reported to be mediated and/or moderated by obesity in a subset of individuals. Obesity can be conceptualized as a neurotoxic phenotype among individuals with NPD as evidenced by alterations in the structure and function of neural circuits and disseminated networks, diminished cognitive performance, and adverse effects on illness trajectory. The neurotoxic effect of obesity provides a rationale for screening, treating, and preventing obesity in neuropsychiatric populations. Research endeavors that aim to refine mediators and moderators of this association as well as novel strategies to reverse the injurious process of obesity on cognition are warranted.

A review of lifestyle factors that contribute to important pathways associated with major depression: diet, sleep and exercise

Research on major depression has confirmed that it is caused by an array of biopsychosocial and lifestyle factors. Diet, exercise and sleep are three such influences that play a significant mediating role in the development, progression and treatment of this condition. This review summarises animal- and human-based studies on the relationship between these three lifestyle factors and major depressive disorder, and their influence on dysregulated pathways associated with depression: namely neurotransmitter processes, immuno-inflammatory pathways, hypothalamic-pituitary-adrenal (HPA) axis disturbances, oxidative stress and antioxidant defence systems, neuroprogression, and mitochondrial disturbances. Increased attention in future clinical studies on the influence of diet, sleep and exercise on major depressive disorder and investigations of their effect on physiological processes will help to expand our understanding and treatment of major depressive disorder. Mental health interventions, taking into account the bidirectional relationship between these lifestyle factors and major depression are also likely to enhance the efficacy of interventions associated with this disorder.

Analysis of manganese superoxide dismutase (MnSOD: Ala-9Val) and glutathione peroxidase (GSH-Px: Pro 197 Leu) gene polymorphisms in mood disorders

We investigated the etiopathogenetic role of manganese superoxide dismutase (MnSOD) (Ala-9Val) and glutathione peroxidase (GSH-Px) (Pro 197 Leu) gene polymorphisms in patients diagnosed with major depressive disorder (MDD) and bipolar I disorder (BD). Eighty patients with MDD, 82 patients with BD (total 162 patients) and 96 healthy controls were enrolled in this study and genotyped using a Real Time-Quantitative Polymer Chain Reaction (RT-qPCR)-based method. The patients with BD and MDD and the controls had a similar distribution of the genotypes and alleles in the Ala-9Val MnSOD gene polymorphism. Comparison of the MDD group and control group regarding the Pro 197 Leu GSH-Px gene polymorphism revealed similar genotype distribution but different allele distribution. The BD group and control group were similar both for genotypes and for alleles when compared regarding the Pro 197 Leu GSH-Px gene polymorphism. The combined analysis (MDD plus BD) also failed to find any association between the Ala-9Val MnSOD and Pro 197 Leu GSH-Px gene polymorphism. Although small statistical power of the current study the significant difference between patients with depression and the control group for the Pro 197 Leu GSH-Px polymorphism indicates that the distribution of these alleles may have a contribution in the physiopathogenesis of depression. One of the limitation of the current study is that the sample size is too small. Understanding of the exact role of Pro 197 Leu GSH-Px polymorphism in the development of depression needs to further studies with more sample size and high statistical power.

In depression, bacterial translocation may drive inflammatory responses, oxidative and nitrosative stress (O&NS), and autoimmune responses directed against O&NS-damaged neoepitopes

OBJECTIVE

Depression is accompanied by activation of immuno-inflammatory and oxidative and nitrosative stress (IO&NS) pathways, and increased IgM/IgA responses to lipopolysaccharide (LPS) of gram-negative commensal bacteria. The latter suggests that bacterial translocation has caused IgM/IgA responses directed against LPS. Bacterial translocation may drive IO&NS responses.

METHOD

To examine the associations between IgM/IgA responses to LPS and IO&NS measurements, including plasma/serum interleukin-1 (IL-1), tumor necrosis factor (TNF)α, neopterin, lysozyme, oxidized LDL (oxLDL) antibodies, peroxides, and IgM (auto)immune responses against malondialdehyde (MDA), azelaic acid, phophatidyl inositol (Pi), NO-tryptophan and NO-tyrosine in depressed patients and controls.

RESULTS

We found significant positive associations between IgM/IgA responses to LPS and oxLDL antibodies, IgM responses against MDA, azelaic acid, Pi, NO-tryptophan, and NO-tyrosine. The IgA responses to LPS were correlated with lysozyme. There were no significant positive correlations between the IgM/IgA responses to LPS and IL-1 and neopterin.

CONCLUSION

The findings show that in depression there is an association between increased bacterial translocation and lysozyme production, an antibacterial compound, O&NS processes, and autoimmune responses directed against O&NS generated neoantigenic determinants. It is suggested that bacterial translocation may drive IO&NS pathways in depression and thus play a role in its pathophysiology.

Increased oxidative stress in patients with depression and its relationship to treatment

Oxidative stress may play a role in the pathogenesis of depression. We tested the hypothesis that urinary F2 isoprostanes, a robust marker of oxidative stress, was increased in patients with depression and associated with symptoms and response to treatment. Urinary F2 isoprostanes was compared in 18 patients with depression and 36 age and sex matched control subjects. In patients, we tested the association between oxidative stress, depression questionnaires and antidepressant treatment. Urinary F2 isoprostane excretion was significantly higher in patients with depression than in control subjects. This association remained significant after adjustment for age, sex and BMI. Depression symptom severity scores were not correlated with F2 isoprostane excretion. Nine patients were treated with sertraline or bupropion for 8 weeks. Depression severity rating scale scores decreased significantly and F2 isoprostane excretion increased. The increase in F2 isoprostane excretion was inversely correlated with the improvement in Hamilton Depression Rating 17 items. In conclusion, oxidative stress is increased in patients with depression. However, although treatment with either bupropion or sertraline reduces the symptoms of depression, it may increase F2 isoprostane excretion. These results suggest that alternative mechanisms, beyond oxidative stress, may be involved in the development of depression and subsequent responses to treatment.

Association between oxidative stress and contextual fear conditioning in Carioca high- and low-conditioned freezing rats

We recently reported two novel breeding lines of rats known as Carioca high-and low-conditioned freezing (CHF and CLF), based on defensive freezing responses to contextual cues previously associated with electric footshock. The anxiety-like profile of these animals from the 7th generation was tested in the elevated plus maze. The results indicated that CHF animals presented a significantly more "anxious" phenotype compared with CLF animals. Animals from the 12th generation were used to evaluate the oxidative stress status of the cortex, hippocampus, and cerebellum. Reactive oxidative species (ROS) were evaluated using 2,7-dichlorofluorescin diacetate (DCFH-DA; a sensor of reactive oxygen species [ROS]), and the levels of malondialdehyde (MDA), an early marker of lipid peroxidation, were assessed. The results indicated that free radical concentrations and MDA levels were significantly higher in all three brain structures in CHF rats compared with CLF rats. Our data also showed that the hippocampus had the highest reactive species and MDA concentrations compared with the cortex and cerebellum in CHF rats. Animals from the 16th generation were used to evaluate the antioxidant enzyme activity of catalase (CAT) and glutathione peroxidase (GPx) within these three brain structures. The results indicated that CAT activity was lower in the cortex and hippocampus in CHF rats compared with CLF rats. No significant difference was observed in the cerebellum. The enzymatic activity of GPx was significantly decreased in all three structures in CHF rats compared with CLF rats. The hippocampus exhibited the highest GPx activity compared with the other two brain structures. These findings suggest the involvement of a redox system in these two bidirectional lines, and the hippocampus might be one of the prime brain structures involved in this state of oxidative stress imbalance.

Schizophrenia is primed for an increased expression of depression through activation of immuno-inflammatory, oxidative and nitrosative stress, and tryptophan catabolite pathways

Schizophrenia and depression are two common and debilitating psychiatric conditions. Up to 61% of schizophrenic patients have comorbid clinical depression, often undiagnosed. Both share significant overlaps in underlying biological processes, which are relevant to the course and treatment of both conditions. Shared processes include changes in cell-mediated immune and inflammatory pathways, e.g. increased levels of pro-inflammatory cytokines and a Th1 response; activation of oxidative and nitrosative stress (O&NS) pathways, e.g. increased lipid peroxidation, damage to proteins and DNA; decreased antioxidant levels, e.g. lowered coenzyme Q10, vitamin E, glutathione and melatonin levels; autoimmune responses; and activation of the tryptophan catabolite (TRYCAT) pathway through induction of indoleamine-2,3-dioxygenase. Both show cognitive and neurostructural evidence of a neuroprogressive process. Here we review the interlinked nature of these biological processes, suggesting that schizophrenia is immunologically primed for an increased expression of depression. Such a conceptualization explains, and incorporates, many of the current perspectives on the nature of schizophrenia and depression, and has implications for the nature of classification and treatment of both disorders. An early developmental etiology to schizophrenia, driven by maternal infection, with subsequent impact on offspring immuno-inflammatory responses, creates alterations in the immune pathways, which although priming for depression, also differentiates the two disorders.

Biomarkers in bipolar disorder: a positional paper from the International Society for Bipolar Disorders Biomarkers Task Force

Although the etiology of bipolar disorder remains uncertain, multiple studies examining neuroimaging, peripheral markers and genetics have provided important insights into the pathophysiologic processes underlying bipolar disorder. Neuroimaging studies have consistently demonstrated loss of gray matter, as well as altered activation of subcortical, anterior temporal and ventral prefrontal regions in response to emotional stimuli in bipolar disorder. Genetics studies have identified several potential candidate genes associated with increased risk for developing bipolar disorder that involve circadian rhythm, neuronal development and calcium metabolism. Notably, several groups have found decreased levels of neurotrophic factors and increased pro-inflammatory cytokines and oxidative stress markers. Together these findings provide the background for the identification of potential biomarkers for vulnerability, disease expression and to help understand the course of illness and treatment response. In other areas of medicine, validated biomarkers now inform clinical decision-making. Although the findings reviewed herein hold promise, further research involving large collaborative studies is needed to validate these potential biomarkers prior to employing them for clinical purposes. Therefore, in this positional paper from the ISBD-BIONET (biomarkers network from the International Society for Bipolar Disorders), we will discuss our view of biomarkers for these three areas: neuroimaging, peripheral measurements and genetics; and conclude the paper with our position for the next steps in the search for biomarkers for bipolar disorder.

Metabolite profiles in the anterior cingulate cortex of depressed patients differentiate those taking N-acetyl-cysteine versus placebo

BACKGROUND

Increased oxidative stress is thought to contribute to the pathophysiology of major depressive disorder (MDD), which is in part due to diminished levels of glutathione, the primary anti-oxidant of the brain. Oral administration of N-acetyl-cysteine (NAC) replenishes glutathione and has therefore been shown to reduce depressive symptoms. Proton magnetic spectroscopy ((1)H-MRS) that allows quantification of brain metabolites pertinent to both MDD and oxidative biology may provide some novel insights into the neurobiological effects of NAC, and in particular metabolite concentrations within the anterior cingulate cortex (ACC) are likely to be important given the key role of this region in the regulation of affect.

OBJECTIVE

The aim of this study was to determine whether the metabolite profile of the ACC in MDD patients predicts treatment with adjunctive NAC versus placebo.

METHODS

This study was nested within a multicentre, randomized, double-blind, placebo-controlled study of MDD participants treated with adjunctive NAC. Participants (n = 76) from one site completed the spectroscopy component at the end of treatment (12 weeks). Spectra from a single-voxel in the ACC were acquired and absolute concentrations of glutamate (Glu), glutamate-glutamine (Glx), N-acetyl-aspartate (NAA) and myo-inositol (mI) were obtained. Binary logistic regression analysis was performed to determine whether metabolite profiles could predict NAC versus placebo group membership.

RESULTS

When predicting group outcome (NAC or placebo), Glx, NAA and mI were a significant model, and had 75% accuracy, while controlling for depression severity and sex. However, the Glu, NAA and mI profile was only predictive at a trend level, with 68.3% accuracy. For both models, the log of the odds of a participant being in the NAC group was positively related to NAA, Glx and Glu levels and negatively related to mI levels.

CONCLUSION

The finding of higher Glx and NAA levels being predictive of the NAC group provides preliminary support for the putative anti-oxidative role of NAC in MDD.

Efficacy of vitamin C as an adjunct to fluoxetine therapy in pediatric major depressive disorder: a randomized, double-blind, placebo-controlled pilot study

BACKGROUND

Current antidepressants used to treat pediatric patients have the disadvantage of limited efficacy and potentially serious side effects. The purpose of this study was to assess the efficacy of vitamin C as an adjuvant agent in the treatment of pediatric major depressive disorder in a six-month, double-blind, placebo-controlled pilot trial.

METHODS

The study group (n=12) was given fluoxetine (10-20 mg/day) plus vitamin C (1000 mg/day) and control group (n=12) administered fluoxetine (10-20 mg/day) plus placebo. The data were analyzed by ANOVA and t-test for independent samples.

RESULTS

Both groups demonstrated significantly improved scores on the Children's Depression Rating Scale (CDRS), the Children's Depression Inventory (CDI), and the Clinical Global Impression (CGI). ANOVA was significantly different on all clinical measurements (group effect, time effect, and interaction), with the exception of group effect and interaction for CGI. Patients treated for six months with fluoxetine and vitamin C showed a significant decrease in depressive symptoms in comparison to the fluoxetine plus placebo group as measured by the CDRS (t=11.36, P<0.0001) and CDI (t=12.27, P<0.0001), but not CGI (t=0.13, P=0.90). No serious adverse effects were observed.

CONCLUSIONS

These preliminary results suggest that vitamin C may be an effective adjuvant agent in the treatment of MDD in pediatric patients.

The promise of N-acetylcysteine in neuropsychiatry

N-Acetylcysteine (NAC) targets a diverse array of factors germane to the pathophysiology of multiple neuropsychiatric disorders including glutamatergic transmission, the antioxidant glutathione, neurotrophins, apoptosis, mitochondrial function, and inflammatory pathways. This review summarises the areas where the mechanisms of action of NAC overlap with known pathophysiological elements, and offers a précis of current literature regarding the use of NAC in disorders including cocaine, cannabis, and smoking addictions, Alzheimer's and Parkinson's diseases, autism, compulsive and grooming disorders, schizophrenia, depression, and bipolar disorder. There are positive trials of NAC in all these disorders, and although many of these require replication and are methodologically preliminary, this makes it one of the most promising drug candidates in neuropsychiatric disorders. The efficacy pattern of NAC interestingly shows little respect for the current diagnostic systems. Its benign tolerability profile, its action on multiple operative pathways, and the emergence of positive trial data make it an important target to investigate.

Coenzyme Q10 displays antidepressant-like activity with reduction of hippocampal oxidative/nitrosative DNA damage in chronically stressed rats

Multiple evidences suggest that depression is accompanied by an induction of oxidative/nitrosative stress (O&NS) pathways and by a reduced antioxidant status. Coenzyme Q10 (CoQ10) is an essential cofactor in the mitochondrial electron transport pathway and has a powerful antioxidant capacity.

METHODS

This study investigated the effect of chronic treatment with CoQ10 (25, 50, 100 and 150 mg/kg/day, i.p. for 3 weeks) on depressive-like behavior and hippocampal, O&NS, and DNA damage, induced by chronic restraint stress (CRS), an experimental model of depression, in rats.

RESULTS

CoQ10 showed a significant antidepressant effect, as evidenced by amelioration of CRS-induced behavioral aberrations in forced swimming and open field tests, elevated corticosterone level and body weight loss. Moreover, CoQ10 dose-dependently restored the hippocampal catalase, glutathione peroxidase and reduced glutathione and decreased the hippocampal malondialdehyde, nitric oxide and 8-hydroxy-2'-deoxyguanosine levels, which indicated a potential protective effect of CoQ10 against hippocampal O&NS lipid peroxidation and DNA damage.

CONCLUSION

CoQ10 possesses antidepressant activity and can protect against CRS-induced hippocampal DNA damage which could be mediated in part by maintaining mitochondrial function and its well documented antioxidant properties. Therefore, CoQ10 may have a potential therapeutic value for the management of depressive disorders. However, further research, is still required to characterize the mechanism of the antidepressant effect of CoQ10 and extend these results before the safe application in humans.

A tomato-rich diet is related to depressive symptoms among an elderly population aged 70 years and over: a population-based, cross-sectional analysis

BACKGROUND

Enhanced oxidative stress or defective anti-oxidant defenses are related to the pathogenesis of depressive symptoms. Lycopene is the most powerful antioxidant amongst the carotenoids. The aim of this study was to investigate the relationship between different vegetables, including tomatoes/tomato products (a major source of lycopene), and depressive symptoms in a community-based elderly population.

METHODS

We analyzed a cross-sectional survey including 986 community-dwelling elderly Japanese individuals aged 70 years and older. Dietary intake was assessed using a valid self-administered diet-history questionnaire, and depressive symptoms were evaluated using the 30-item Geriatric Depression Scale with 2 cut-off points: 11 (mild and severe) and 14 (severe) or use of anti-depressive agents.

RESULTS

The prevalence of mild and severe and severe depressive symptoms was 34.9% and 20.2%, respectively. After adjustments for potentially confounding factors, the odds ratios of having mild and severe depressive symptoms by increasing levels of tomatoes/tomato products were 1.00, 0.54, and 0.48 (p for trend <0.01). Similar relationships were also observed in the case of severe depressive symptoms. In contrast, no relationship was observed between intake of other kinds of vegetables and depressive symptoms.

LIMITATIONS

This is a cross-sectional study, and not for making a clinical diagnosis of depressive episodes.

CONCLUSIONS

This study demonstrated that a tomato-rich diet is independently related to lower prevalence of depressive symptoms. These results suggest that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms. Further studies are needed to confirm these findings.

The impact of GPX1 on the association of groundwater selenium and depression: a Project FRONTIER study

BACKGROUND

Prior animal model and human-based studies have linked selenium concentrations to decreased risk for depression; however, this work has not focused on household groundwater levels or specific depressive symptoms. The current study evaluated the link between groundwater selenium levels and depression. We also sought to determine if a functional polymorphism in the glutathione peroxidase 1 (GPX1) gene impacted this link.

METHODS

We used a cross-sectional design to analyze data from 585 participants (183 men and 402 women) from Project FRONTIER, a study of rural health in West Texas. Residential selenium concentrations were estimated using Geospatial Information System (GIS) analyses. Linear regression models were created using Geriatric Depression Scale (GDS-30) total and subfactor scores as outcome variables and selenium concentrations as predictor variables. Analyses were re-run after stratification of the sample on GPX1 Pro198Leu genotype (rs1050454).

RESULTS

Selenium levels were significantly and negatively related to all GDS and subfactor scores accounting for up to 17% of the variance beyond covariates. Selenium was most strongly protective against depression among homozygous carriers of the C allele at the Pro198Leu polymorphism of the GPX1 gene. Analyses also point towards a gene-environmental interaction between selenium exposure and GPX1 polymorphism.

CONCLUSION

Our results support the link between groundwater selenium levels and decreased depression symptoms. These findings also highlight the need to consider the genetics of the glutathione peroxidase system when examining this relationship, as variation in the GPX1 gene is related to depression risk and significantly influences the protective impact of selenium, which is indicative of a gene-environment interaction.

The relevance of oxidative stress status in first episode and recurrent depression

Oxidative and nitrosative stress (O&NS) could play an important role in the pathophysiology of major depression (MDD). The aim of the present work was to evaluate the specific activity of the main peripheral antioxidant defences (superoxide dismutase--SOD and glutathione peroxidase--GPX) and the level of malondialdehyde--MDA (a lipid peroxidation maker), in depressed patients, as compared to an age-matched control group. Also, we were interested to see if there are any differences between first episode vs. recurrent depression groups, in terms of oxidative stress markers. Additionally, we want it to investigate the effects of different antidepressant medication (mirtazapine, venlafaxine, tianeptine and escitalopram) on oxidative status of depressed patients. Our results showed an increased oxidative stress status in the serum of patients with MDD, expressed by a significant decrease of both SOD and GPX specific activities and a significant increase of the lipid peroxidation marker MDA, as compared to the control group. When we analyzed the oxidative stress status in depressed patients based on chronicity we observed significant decrease of SOD and GPX specific activities in recurrent depression group, as compared to the first episode group. Moreover, a very significant increase in MDA concentration was observed in recurrent depression patients, as compared to the first episode group. Our work provides additional evidences of increased oxidative stress in MDD, expressed by altered antioxidant enzyme activity and increased levels of lipid peroxidation. Also, it seems that sub-classifying depression into different subtypes, based on chronicity, can predict differences in the levels of some various oxidative stress markers.

Reduced antioxidant defense systems in schizophrenia and bipolar I disorder

Numerous evidence and proofs suggest that the oxidative stress contributes to the pathogenesis of schizophrenia (SZ) and bipolar disorder (BD). The aim of this study is to determine the glutathione levels and the antioxidant enzyme activities in blood samples of patients suffering from SZ and patients with bipolar disorder in comparison with the healthy controlled subjects. It was a case-controlled study carried on upon three groups: forty-six SZ patients (41 men and 5 women, mean age=33.2±7years), thirty BD patients (25 men and 5 women, mean age=31.3±8years) and forty healthy controls (33 men and 7 women, mean age=32.3±7years). The glutathione levels are the total glutathione (GSHt), the reduced glutathione (GSHr), and the oxidized glutathione (GSSG) and the antioxidant enzyme activities that are the superoxide dismutase (SOD), the glutathione peroxidase (GPx), and the catalase (CAT) are determined by the spectrophotometer. We noticed that the GSHt and the GSHr levels significantly decreased in both SZ and BD patients in comparison with the healthy control subjects. As for SOD and CAT activities they remained lower for the patients with SZ when compared both with the controls or the BD patients. We noticed as well that the CAT activity was significantly lower in the BD group than that in the control group, whereas, GPx activity showed no significant change in each group. Hence, this report of the decreased plasma levels of GSHt and GSHr, and the impaired antioxidant enzyme activities in SZ and BD patients aims at highlighting the GSH deficit that seems to be contributing to these disorders, and showing that it may be an important indirect biomarker of the oxidative stress for the SZ and BD.

IgM-mediated autoimmune responses directed against anchorage epitopes are greater in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) than in major depression

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and depression are considered to be neuro-immune disorders (Maes and Twisk, BMC Medicine 8:35, 2010). There is also evidence that depression and ME/CFS are accompanied by oxidative and nitrosative stress (O&NS) and by increased autoantibodies to a number of self-epitopes some of which have become immunogenic due to damage by O&NS. The aim of this study is to examine IgM-mediated autoimmune responses to different self-epitopes in ME/CFS versus depression. We examined serum IgM antibodies to three anchorage molecules (palmitic and myristic acid and S-farnesyl-L-cysteine); acetylcholine; and conjugated NO-modified adducts in 26 patients with major depression; 16 patients with ME/CFS, 15 with chronic fatigue; and 17 normal controls. Severity of fatigue and physio-somatic (F&S) symptoms was measured with the Fibromyalgia and Chronic Fatigue Syndrome Rating Scale. Serum IgM antibodies to the three anchorage molecules and NO-phenylalanine were significantly higher in ME/CFS than in depression. The autoimmune responses to oxidatively, but not nitrosatively, modified self-epitopes were significantly higher in ME/CFS than in depression and were associated with F&S symptoms. The autoimmune activity directed against conjugated acetylcholine did not differ significantly between ME/CFS and depression, but was greater in the patients than controls. Partially overlapping pathways, i.e. increased IgM antibodies to a multitude of neo-epitopes, underpin both ME/CFS and depression, while greater autoimmune responses directed against anchorage molecules and oxidatively modified neo-epitopes discriminate patients with ME/CFS from those with depression. These autoimmune responses directed against neoantigenic determinants may play a role in the dysregulation of key cellular functions in both disorders, e.g. intracellular signal transduction, cellular differentiation and apoptosis, but their impact may be more important in ME/CFS than in depression.

Evaluation of behavioral and neurochemical changes induced by ketamine in rats: implications as an animal model of mania

Bipolar disorder (BD) is a chronic, prevalent, and highly debilitating psychiatric illness characterized by recurrent manic and depressive episodes. Mood stabilizing agents such as lithium and valproate are two primary drugs used to treat BD. To develop a novel animal model of mania (hallmark of BD), it is important to assess the therapeutic and prophylactic effect of these mood stabilizers on the new candidate target animal model. The present work investigates the therapeutic and prophylactic value of lithium and valproate in a novel preclinical animal model of mania, induced by ketamine. In the prevention protocol, wistar rats were pretreated with lithium (47.5 mg/kg, i.p., twice a day), valproate (200 mg/kg, i.p., twice a day), or saline (i.p., twice a day) for 14 days. Between days 8 and 14, the rats were treated with ketamine (25 mg/kg, i.p.) or saline. In the reversal protocol, rats first received ketamine (25 mg/kg, i.p.) or saline. After, the administration of lithium, valproate, or saline was carried out for seven days. Our results indicated that lithium and valproate reversed and prevented ketamine-induced hyperlocomotion. Moreover, lithium and valproate reversed (prefrontal cortex, hippocampus, and striatum) and prevented (prefrontal cortex, hippocampus, striatum, and amygdala) the increase of the TBARS level induced by ketamine. The protein carbonyl formation, induced by ketamine, was reversed by lithium and valproate in the prefrontal cortex, hippocampus, and striatum, and prevented only in the amygdala. These findings support the notion that the administration of ketamine might be a promising pharmacological animal model of mania, which could play a role in the pathophysiology of BD.

Multiple antidepressant potential modes of action of curcumin: a review of its anti-inflammatory, monoaminergic, antioxidant, immune-modulating and neuroprotective effects

Curcumin is the principal curcuminoid of the popular Indian spice turmeric and has attracted increasing attention for the treatment of a range of conditions. Research into its potential as a treatment for depression is still in its infancy, although several potential antidepressant mechanisms of action have been identified. Research completed to date on the multiple effects of curcumin is reviewed in this paper, with a specific emphasis on the biological systems that are compromised in depression. The antidepressant effects of curcumin in animal models of depression are summarised, and its influence on neurotransmitters such as serotonin and dopamine is detailed. The effects of curcumin in moderating hypothalamus-pituitary-adrenal disturbances, lowering inflammation and protecting against oxidative stress, mitochondrial damage, neuroprogression and intestinal hyperpermeability, all of which are compromised in major depressive disorder, are also summarised. With increasing interest in natural treatments for depression, and efforts to enhance current treatment outcomes, curcumin is presented as a promising novel, adjunctive or stand-alone natural antidepressant.

Cerebrospinal fluid metabolome in mood disorders-remission state has a unique metabolic profile

Targeted metabolomics provides an approach to quantify metabolites involved in specific molecular pathways. We applied an electrochemistry-based, targeted metabolomics platform to define changes in tryptophan, tyrosine, purine and related pathways in the depressed and remitted phases of major depressive disorder (MDD). Biochemical profiles in the cerebrospinal fluid of unmedicated depressed (n = 14; dMDD) or remitted MDD subjects (n = 14; rMDD) were compared against those in healthy controls (n = 18; HC). The rMDD group showed differences in tryptophan and tyrosine metabolism relative to the other groups. The rMDD group also had higher methionine levels and larger methionine-to-glutathione ratios than the other groups, implicating methylation and oxidative stress pathways. The dMDD sample showed nonsignificant differences in the same direction in several of the metabolic branches assessed. The reductions in metabolites associated with tryptophan and tyrosine pathways in rMDD may relate to the vulnerability this population shows for developing depressive symptoms under tryptophan or catecholamine depletion.

Peripheral oxidative damage in early-stage mood disorders: a nested population-based case-control study

Systemic toxicity is a relevant dimension of pathophysiology in bipolar disorder, and oxidative damage is one potential link between central and peripheral pathology. Although there is mounting evidence that chronic bipolar disorder is associated with oxidative stress, studies in the early stages of bipolar disorder are scarce, and heavily reliant on clinical in lieu of population studies. The objective of this study was to confirm leading hypotheses about the role of oxidative damage in bipolar disorder. To that end, we nested a case-control study in a population-based study of young adults aged 18-24 yr. After an initial psychopathology screen, all people with a lifetime history of (hypo)mania and matched controls underwent a structured diagnostic interview. This yielded a sample of 231 participants, in whom we measured serum protein carbonyl content (PCC) and thiobarbituric acid reactive substances (TBARS). People with bipolar disorder had higher PCC levels than healthy subjects. Those with major depression were not different from control subjects in either PCC or TBARS levels. Both bipolar disorder and major depression were associated with higher PCC levels in the a priori regression model controlling for possible confounders. These findings indicate that protein oxidative damage is present from early stages and can be seen as a sign of early illness activity in mood disorders.

Novel therapeutic targets in depression: minocycline as a candidate treatment

Mood disorders are marked by high rates of non-recovery, recurrence, and chronicity, which are insufficiently addressed by current therapies. Several patho-etiological models have been proposed that are not mutually exclusive and include but are not limited to the monoamine, inflammatory, neurotrophic, gliotrophic, excitatory, and oxidative stress systems. A derivative of these observations is that treatment(s) which target one or more of these mechanistic steps may be capable of mitigating, or preventing, disparate psychopathological features. Minocycline is an agent with pleiotropic properties that targets multiple proteins and cellular processes implicated in the patho-etiology of mood disorders. Moreover, preclinical and preliminary clinical evidence suggests that minocycline possesses antidepressant properties. Herein, we provide the rationale for conducting a randomized, controlled trial to test the antidepressant properties of minocycline.

Synergist effects of n-acetylcysteine and deferoxamine treatment on behavioral and oxidative parameters induced by chronic mild stress in rats

A growing body of evidence has pointed to a relationship between oxidative stress and depression. Thus, the present study was aimed at evaluating the effects of the antioxidants n-acetylcysteine (NAC), deferoxamine (DFX) or their combination on sweet food consumption and oxidative stress parameters in rats submitted to 40days of exposure to chronic mild stress (CMS). Our results showed that in stressed rats treated with saline, there was a decrease in sweet food intake and treatment with NAC or NAC in combination with DFX reversed this effect. Treatment with NAC and DFX decreased the oxidative damage, which include superoxide and TBARS production in submitochondrial particles, and also thiobarbituric acid reactive substances (TBARS) levels and carbonyl proteins in the prefrontal cortex, amygdala and hippocampus. Treatment with NAC and DFX also increased the activity of the antioxidant enzymes, superoxide dismutase and catalase in the same brain areas. Even so, a combined treatment with NAC and DFX produced a stronger increase of antioxidant activities in the prefrontal cortex, amygdala and hippocampus. The results described here indicate that co-administration may induce a more pronounced antidepressant activity than each treatment alone. In conclusion, these results suggests that treatment with NAC or DFX alone or in combination on oxidative stress parameters could have positive effects against neuronal damage caused by oxidative stress in major depressive disorders.

Diphenyl diselenide ameliorates behavioral and oxidative parameters in an animal model of mania induced by ouabain

Bipolar disorder (BD) is a common and severe mood disorder associated with higher rates of suicide and disability. Ouabain, a Na(+)/K(+)-ATPase inhibitor, induces behavioral changes in rats and has been used as a model of mania. The aim of this study was to investigate if diphenyl diselenide [(PhSe)(2)], an organoselenium compound with pharmacological properties, is effective against ouabain-induced hyperactivity and alterations in cerebral oxidative status of rats. Male Wistar rats were treated with a single dose of (PhSe)(2) (50 mg/kg, p.o.) 30 min before i.c.v. injection of ouabain (5 μl, 10(-5) M) or with the mood stabilizer, lithium chloride (LiCl) (45 mg/kg, p.o.), twice a day, for 7 days before the administration of ouabain. Open-field locomotion was quantified after ouabain administration. Thiobarbituric acid reactive substances (TBARS), oxidatively modified proteins, tyrosine nitration, ascorbic acid and non-protein thiols (NPSH) levels and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were determined in the whole brain. Ouabain increased locomotor activity in the open-field test and pretreatment with (PhSe)(2) or LiCl blocked this effect. In addition, ouabain increased lipid peroxidation and oxidatively modified proteins, demonstrated by a significant increase in TBARS levels and carbonyl content, which were attenuated by pretreatment with (PhSe)(2) or LiCl. The activities of SOD and CAT were increased by ouabain. LiCl was effective on preventing the increases of both enzyme activities, but (PhSe)(2) attenuated the ouabain effect in SOD activity. GPx and GR activities, ascorbic acid, NPSH and tyrosine nitration levels were not altered in all experimental groups. Similarly to LiCl, (PhSe)(2) produced an antimanic-like action, since it was effective against the locomotor hyperactivity elicited by ouabain. The results also indicated that (PhSe)(2) was effective against oxidative stress caused by ouabain in rats.

Psychotropic effects of antimicrobials and immune modulation by psychotropics: implications for neuroimmune disorders

Antimicrobial compounds and psychotropic medications often share overlapping mechanisms of actions and pharmacological effects. The immune system appears to be an important site of interaction as several antimicrobials display neurological and, at times, direct psychotropic effects, while psychotropics have shown significant immunomodulatory properties. The isoniazid class of antibiotics for example has been shown to possess monoamine oxidase activity, while selective serotonin reuptake inhibitors have shown significant effects on leukocyte populations. As the importance of the immune system's role in CNS homeostasis and disease continues to move to the forefront of neuropsychiatric research, these shared pharmacological effects may provide an important insight, elucidating the complexities in neuroimmune pathophysiology and guiding the development of potential treatments.

Cognitive impairment is related to oxidative stress and chemokine levels in first psychotic episodes

INTRODUCTION

This study measures the levels of various markers of oxidative stress and inflammation in blood samples from first-episode psychosis (FEP) patients, and examines the association between these peripheral biomarkers and cognitive performance at 6 months after treatment.

METHODS

Twenty-eight FEP patients and 28 healthy controls (matched by age, sex and educational level) had blood samples taken at admission for assessment of total antioxidant status, superoxide dismutase (SOD), total glutathione (GSH), catalase (CAT), glutathione peroxidase, lipid peroxidation, nitrites and the chemokine monocyte chemoattractant protein-1 (MCP-1). A battery of cognitive tests was also applied to the healthy controls and those FEP patients who were in remission at 6 months after the acute episode.

RESULTS

FEP patients had significantly lower levels of total antioxidant status, catalase and glutathione peroxidase, compared with the healthy controls. Regression analyses found that MCP-1 levels were negatively associated with learning and memory (verbal and working), nitrite levels were negatively associated with executive function, and glutathione levels were positively associated with executive function.

CONCLUSION

Our results suggest an association between certain peripheral markers of oxidative stress and inflammation and specific aspects of cognitive functioning in FEP patients. Further studies on the association between MCP-1 and cognition are warranted.

Effects of lithium therapy on Na+-K+-ATPase activity and lipid peroxidation in bipolar disorder

OBJECTIVES

Oxidative stress induced lipid peroxidation along with a reduced Na(+)-K(+)-ATPase activity has been implicated in the pathophysiology of bipolar disorders (BPD). Although, lithium therapy results in significant improvement in the symptoms of the disease, studies regarding its effect on the altered sodium pump activity and lipid peroxidation status have come out with conflicting results. The present study was undertaken to evaluate the status of lipid peroxidation and analyze the role of lithium and Na(+)-K(+)-ATPase activity in its regulation in BPD patients in our region.

METHOD

We measured RBC membrane Na(+)-K(+)-ATPase activity and serum thiobarbituric acid reacting substances (TBARS) level in 73 BPD patients and serum lithium, in addition, in 48 patients receiving lithium therapy among them.

RESULTS

Na(+)-K(+)-ATPase activity and serum TBARS level were significantly decreased and increased respectively in all BPD patients compared to age and sex matched healthy controls. Same trend was observed in the BPD patients stabilized on lithium therapy compared to the lithium naive ones. Although, the enzyme activity showed a reciprocal relationship with TBARS in all patients of BPD, a significant positive correlation and dependence of the enzyme activity was evident with serum lithium level only in the lithium stabilized BPD group.

CONCLUSIONS

BPD patients showed significantly compromised Na(+)-K(+)-ATPase activity and increased lipid peroxidation. Lithium induced improvement in the enzyme activity was associated with significant reduction in lipid peroxidation. Enhancement of the Na(+)-K(+)-ATPase activity by optimum dosage of lithium may be a potential contributing factor for reducing oxidative stress in BPD patients.

A review of research trends in physiological abnormalities in autism spectrum disorders: immune dysregulation, inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures

Recent studies have implicated physiological and metabolic abnormalities in autism spectrum disorders (ASD) and other psychiatric disorders, particularly immune dysregulation or inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures ('four major areas'). The aim of this study was to determine trends in the literature on these topics with respect to ASD. A comprehensive literature search from 1971 to 2010 was performed in these four major areas in ASD with three objectives. First, publications were divided by several criteria, including whether or not they implicated an association between the physiological abnormality and ASD. A large percentage of publications implicated an association between ASD and immune dysregulation/inflammation (416 out of 437 publications, 95%), oxidative stress (all 115), mitochondrial dysfunction (145 of 153, 95%) and toxicant exposures (170 of 190, 89%). Second, the strength of evidence for publications in each area was computed using a validated scale. The strongest evidence was for immune dysregulation/inflammation and oxidative stress, followed by toxicant exposures and mitochondrial dysfunction. In all areas, at least 45% of the publications were rated as providing strong evidence for an association between the physiological abnormalities and ASD. Third, the time trends in the four major areas were compared with trends in neuroimaging, neuropathology, theory of mind and genetics ('four comparison areas'). The number of publications per 5-year block in all eight areas was calculated in order to identify significant changes in trends. Prior to 1986, only 12 publications were identified in the four major areas and 51 in the four comparison areas (42 for genetics). For each 5-year period, the total number of publications in the eight combined areas increased progressively. Most publications (552 of 895, 62%) in the four major areas were published in the last 5 years (2006-2010). Evaluation of trends between the four major areas and the four comparison areas demonstrated that the largest relative growth was in immune dysregulation/inflammation, oxidative stress, toxicant exposures, genetics and neuroimaging. Research on mitochondrial dysfunction started growing in the last 5 years. Theory of mind and neuropathology research has declined in recent years. Although most publications implicated an association between the four major areas and ASD, publication bias may have led to an overestimation of this association. Further research into these physiological areas may provide insight into general or subset-specific processes that could contribute to the development of ASD and other psychiatric disorders.

Hesperidin ameliorates immobilization-stress-induced behavioral and biochemical alterations and mitochondrial dysfunction in mice by modulating nitrergic pathway

The present study was aimed to evaluate the protective effect of hesperidin against immobilization-stress-induced alterations in biochemical, behavioral, and mitochondrial functions in mice. In many instances neuroscientists have reported that acute immobilization stress for 6 h resulted in anxiety and impaired locomotor activity due to excess oxidative-nitrergic stress, depletion of antioxidant defense mechanisms, and mitochondrial dysfunction in animals. In the present study, 6 h of acute immobilization stress had significantly altered the behavioral (anxiety and memory) and biochemical parameters coupled with mitochondrial dysfunction in Swiss albino mice. Fourteen days of pretreatment with Hesperidin (50 and 100 mg/kg, p.o.) significantly and dose-dependently inhibited the behavioral and biochemical alterations and mitochondrial dysfunction caused by acute immobilization stress. Furthermore, pre-treatment of l-arginine (50 mg/kg, i.p.), a nitric oxide precursor, reversed the protective effect of Hesperidin (50 and 100 mg/kg) (P < 0.05). In contrast, pretreatment of l-NAME (5 mg/kg, i.p.), a nitric oxide synthase inhibitor, potentiated the protective effect of Hesperidin (P < 0.05). These results suggest the possible involvement of nitrergic pathway in the protective effect Hesperidin against immobilization-stress-induced behavioral, biochemical, and mitochondrial dysfunction in mice.

Ascorbic acid treatment, similarly to fluoxetine, reverses depressive-like behavior and brain oxidative damage induced by chronic unpredictable stress

Reactive oxygen species (ROS) have been shown to play a role in the pathophysiology of depression. Taking into account that experimental chronic unpredictable stress (CUS) induces depressive-like behavior and that ascorbic acid has antidepressant-like effect in animals, the objective of this study was to investigate the influence of ascorbic acid on depressive-like behavior induced by CUS paradigm, serum corticosterone levels and markers of oxidative stress in cerebral cortex and hippocampus of mice. Animals were submitted to CUS procedure during 14 days. From the 8th to the 14th day mice received ascorbic acid (10 mg/kg) or fluoxetine (10 mg/kg, conventional antidepressant, positive control) once a day by oral route. On 15th day behavioral and biochemical parameters were analyzed. CUS exposure caused a depressive-like behavior evidenced by the increased immobility time in the tail suspension test and decreased time in which mice spent grooming in the splash test. Depressive-like behavior induced by CUS was accompanied by a significant increased lipid peroxidation (cerebral cortex and hippocampus), decreased catalase (CAT) (cerebral cortex and hippocampus) and glutathione reductase (GR) (hippocampus) activities and reduced levels of glutathione (cerebral cortex). Repeated ascorbic acid or fluoxetine administration significantly reversed CUS-induced depressive-like behavior and oxidative damage. No alteration was observed in locomotor activity, corticosterone levels and glutathione peroxidase (GPx) activity. These findings indicate a rapid and robust effect of ascorbic acid in reversing behavioral and biochemical alterations induced by CUS in mice, suggesting that this vitamin may be an alternative approach for the management of depressive symptoms.

New drug targets in depression: inflammatory, cell-mediated immune, oxidative and nitrosative stress, mitochondrial, antioxidant, and neuroprogressive pathways. And new drug candidates--Nrf2 activators and GSK-3 inhibitors

This paper reviews new drug targets in the treatment of depression and new drug candidates to treat depression. Depression is characterized by aberrations in six intertwined pathways: (1) inflammatory pathways as indicated by increased levels of proinflammatory cytokines, e.g. interleukin-1 (IL-1), IL-6, and tumour necrosis factor α. (2) Activation of cell-mediated immune pathways as indicated by an increased production of interferon γ and neopterin. (3) Increased reactive oxygen and nitrogen species and damage by oxidative and nitrosative stress (O&NS), including lipid peroxidation, damage to DNA, proteins and mitochondria. (4) Lowered levels of key antioxidants, such as coenzyme Q10, zinc, vitamin E, glutathione, and glutathione peroxidase. (5) Damage to mitochondria and mitochondrial DNA and reduced activity of respiratory chain enzymes and adenosine triphosphate production. (6) Neuroprogression, which is the progressive process of neurodegeneration, apoptosis, and reduced neurogenesis and neuronal plasticity, phenomena that are probably caused by inflammation and O&NS. Antidepressants tend to normalize the above six pathways. Targeting these pathways has the potential to yield antidepressant effects, e.g. using cytokine antagonists, minocycline, Cox-2 inhibitors, statins, acetylsalicylic acid, ketamine, ω3 poly-unsaturated fatty acids, antioxidants, and neurotrophic factors. These six pathways offer new, pathophysiologically guided drug targets suggesting that novel therapies could be developed that target these six pathways simultaneously. Both nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activators and glycogen synthase kinase-3 (GSK-3) inhibitors target the six above-mentioned pathways. GSK-3 inhibitors have antidepressant effects in animal models of depression. Nrf2 activators and GSK-3 inhibitors have the potential to be advanced to phase-2 clinical trials to examine whether they augment the efficacy of antidepressants or are useful as monotherapy.

Mechanistic explanations how cell-mediated immune activation, inflammation and oxidative and nitrosative stress pathways and their sequels and concomitants play a role in the pathophysiology of unipolar depression

This paper reviews that cell-mediated-immune (CMI) activation and inflammation contribute to depressive symptoms, including anhedonia; anxiety-like behaviors; fatigue and somatic symptoms, e.g. illness behavior or malaise; and mild cognitive impairment (MCI). These effects are in part mediated by increased levels of pro-inflammatory cytokines (PICs), e.g. interleukin-1 (IL-1), IL-6 and tumor necrosis factor (TNF)α, and Th-1-derived cytokines, such as IL-2 and interferon (IFN)γ. Moreover, new pathways, i.e. concomitants and sequels of CMI activation and inflammation, were detected in depression: (1) Induction of indoleamine 2,3-dioxygenase (IDO) by IFNγ and some PICs is associated with depleted plasma tryptophan, which may interfere with brain 5-HT synthesis, and increased production of anxiogenic and depressogenic tryptophan catabolites. (2) Increased bacterial translocation may cause depression-like behaviors by activating the cytokine network, oxidative and nitrosative stress (O&NS) pathways and IDO. (3) Induction of O&NS causes damage to membrane ω3 PUFAs, functional proteins, DNA and mitochondria, and autoimmune responses directed against intracellular molecules that may cause dysfunctions in intracellular signaling. (4) Decreased levels of ω3 PUFAs and antioxidants, such as coenzyme Q10, glutathione peroxidase or zinc, are associated with an increased inflammatory potential; more oxidative damage; the onset of specific symptoms; and changes in the expression or functions of brain 5-HT and N-methyl-d-aspartate receptors. (5) All abovementioned factors cause neuroprogression, that is a combination of neurodegeneration, neuronal apoptosis, and lowered neurogenesis and neuroplasticity. It is concluded that depression may be the consequence of a complex interplay between CMI activation and inflammation and their sequels/concomitants which all together cause neuroprogression that further shapes the depression phenotype. Future research should employ high throughput technologies to collect genetic and gene expression and protein data from patients with depression and analyze these data by means of systems biology methods to define the dynamic interactions between the different cell signaling networks and O&NS pathways that cause depression.

Anxiety- and depression-like behaviors are accompanied by an increase in oxidative stress in a rat model of fetal alcohol spectrum disorders: Protective effects of voluntary physical exercise

Prenatal ethanol exposure can damage the developing nervous system, producing long-lasting impairments in both brain structure and function. In this study we analyzed how exposure to this teratogen during the period of brain development affects the intracellular redox state in the brain as well as the development of anxiety- and depressive-like phenotypes. Furthermore, we also tested whether aerobic exercise might have therapeutic potential for fetal alcohol spectrum disorders (FASD) by increasing neuronal antioxidant capacity and/or by alleviating ethanol-induced behavioral deficits. Sprague-Dawley rats were administered ethanol across all three-trimester equivalents (i.e., throughout gestation and during the first 10 days of postnatal life). Ethanol-exposed and control animals were assigned to either sedentary or running groups at postnatal day (PND) 48. Runners had free access to a running wheel for 12 days and at PND 60 anxiety- and depressive-like behaviors were assessed. Perinatal ethanol exposure resulted in the occurrence of depressive and anxiety-like behaviors in adult rats without affecting their locomotor activity. Voluntary wheel running reversed the depressive-like behaviors in ethanol-exposed males, but not in ethanol-exposed females. Levels of lipid peroxidation and protein oxidation were significantly increased in the hippocampus and cerebellum of ethanol-exposed rats, and there was a concomitant reduction in the levels of the endogenous antioxidant glutathione. Voluntary exercise was able to reverse the deficits in glutathione both in ethanol-exposed males and females. Thus, while voluntary physical exercise increased glutathione levels in both sexes, its effects at the behavioral level were sex dependent, with only ethanol-exposed male runners showing a decrease in depressive-like behaviors.

Decreased glutathione levels and impaired antioxidant enzyme activities in drug-naive first-episode schizophrenic patients

BACKGROUND

The aim of this study was to determine glutathione levels and antioxidant enzyme activities in the drug-naive first-episode patients with schizophrenia in comparison with healthy control subjects.

METHODS

It was a case-controlled study carried on twenty-three patients (20 men and 3 women, mean age = 29.3 ± 7.5 years) recruited in their first-episode of schizophrenia and 40 healthy control subjects (36 men and 9 women, mean age = 29.6 ± 6.2 years). In patients, the blood samples were obtained prior to the initiation of neuroleptic treatments. Glutathione levels: total glutathione (GSHt), reduced glutathione (GSHr) and oxidized glutathione (GSSG) and antioxidant enzyme activities: superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) were determined by spectrophotometry.

RESULTS

GSHt and reduced GSHr were significantly lower in patients than in controls, whereas GSSG was significantly higher in patients. GPx activity was significantly higher in patients compared to control subjects. CAT activity was significantly lower in patients, whereas the SOD activity was comparable to that of controls.

CONCLUSION

This is a report of decreased plasma levels of GSHt and GSHr, and impaired antioxidant enzyme activities in drug-naive first-episode patients with schizophrenia. The GSH deficit seems to be implicated in psychosis, and may be an important indirect biomarker of oxidative stress in schizophrenia early in the course of illness. Finally, our results provide support for further studies of the possible role of antioxidants as neuroprotective therapeutic strategies for schizophrenia from early stages.

Restorative biological processes and health

Research on psychological influences on physiology primarily focuses on biological responses during stressful challenges, and how those responses can become dysregulated with prolonged or repeated exposure to stressful circumstances. At the same time, humans spend considerable time recovering from those challenges, and a host of biological processes involved in restoration and repair take place during normal, non-stressed activities. We review restorative biological processes and evidence for links between psychosocial factors and several restorative processes including sleep, wound healing, antioxidant production, DNA repair, and telomerase function. Across these biological processes, a growing body of evidence suggests that experiencing negative emotional states, including acute and chronic stress, depressive symptoms, and individual differences in negative affectivity and hostility, can influence these restorative processes. This review calls attention to restorative processes as fruitful mechanisms and outcomes for future biobehavioral research.

Venlafaxine protects against stress-induced oxidative DNA damage in hippocampus during antidepressant testing in mice

Venlafaxine (VLF) is an approved antidepressant that is claimed to have superior clinical efficacy to comparable drugs. Recently, many studies showed the relationship between depression and increased oxidative stress. This study investigated the relationship between the antidepressant effect of VLF and its ability to protect animals against stress-induced oxidative lipid peroxidation and DNA damage induced during antidepressant testing.

METHODS

The antidepressant effect of long-term treatment (21 days) of VLF in doses 5, 10 and 20mg/kg/day, i.p. was tested using forced swimming test (FST) and tail suspension test (TST). The effects of VLF on hippocampal lipid peroxidation (MDA), nitric oxide (NO), glutathione (GSH), total antioxidant (TAC) levels and glutathione-S-transferase (GST) activity were tested. Furthermore, the corresponding changes in serum and hippocampal 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured.

RESULTS

Long-term VLF treatment showed a significant, antidepressant effect in both FST and TST. VLF could decrease the hippocampal MDA and NO and to increase hippocampal GSH and TAC levels and GST activity in the tested animals. Only GSH and TAC levels were increased by VLF in the non-tested animals. In addition, both serum and hippocampal 8-OHdG levels were significantly reduced by VLF in animals exposed to antidepressant tests.

CONCLUSION

Long-term VLF treatment in the effective antidepressant doses can protect against stress-induced oxidative cellular and DNA damage. This action may be through antagonizing the oxidative stress and enhancing the antioxidant defense mechanisms. Consequently, pharmacological modulation of stress-induced oxidative DNA damage as a possible stress-management approach should be an important avenue of further research.

Therapeutic effects of propolis essential oil on anxiety of restraint-stressed mice

Propolis has a broad spectrum of biological activities; however, whether its essential oils have neuroprotective effects is unknown. In this study, we found that propolis essential oil (PEO) could significantly reverse the anxiety-like behavior of restraint-stressed mice, and has no effect on locomotor activity. Furthermore, PEO significantly decreased the plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH) and malondialdehyde (MDA), whereas it increased the activity of superoxide dismutase (SOD) in restraint-stressed mice. These results strongly suggest that PEO has therapeutic effects on anxiety through antagonizing the hyperfunction of hypothalamic-pituitary-adrenal (HPA) axis and improving the ability of antioxidation in brain tissue.

Glutamate cysteine ligase (GCL) and self reported depression: an association study from the HUNT

BACKGROUND

There is increasing evidence suggesting oxidative stress may play a role in the aetiology of depression. Glutathione is the brain's predominant free radical scavenger, and associated polymorphisms of the glutamate cysteine ligase (GCL) gene have been reported for related psychiatric disorders. The aim of the study was to investigate candidate polymorphisms of GCL validated in schizophrenia and their association with current state depression, as measured by the Hospital Anxiety and Depression Scale (HADS).

METHODS

Polymorphisms were genotyped on 983 cases and 967 controls selected from a population sample of adults participating in the Nord-Trøndelag Health Study. Cases were the top scoring individuals (98.5th percentile) on the HADS depression subscale while the controls were randomly selected from below this cut-off. The polymorphisms comprised three SNPs from GCLM, the gene encoding the GCL modifier and 9 SNPs plus a trinucleotide repeat (TNTR) from intron 1 and the 5'UTR of GCLC, the gene encoding the GCL catalytic subunit. Using the linkage disequilibrium between the GCLC markers we also tested whether SNPs could represent the variation of the TNTR.

RESULTS

The candidate polymorphisms showed no evidence for association with depression. The C allele of SNP rs9474592 is coupled with the 9 GAG repeats allele of the TNTR, r²=0.81. None of the other SNPs either individually or as two or three-SNP haplotypes was associated with the TNTR alleles.

LIMITATIONS

Depression was self-reported and measured at one time point.

CONCLUSIONS

This study provides no evidence to suggest that polymorphisms of GCL are associated with self-reported depression.

A review on the oxidative and nitrosative stress (O&NS) pathways in major depression and their possible contribution to the (neuro)degenerative processes in that illness

This paper reviews the body of evidence that major depression is accompanied by a decreased antioxidant status and by induction of oxidative and nitrosative (IO&NS) pathways. Major depression is characterized by significantly lower plasma concentrations of a number of key antioxidants, such as vitamin E, zinc and coenzyme Q10, and a lowered total antioxidant status. Lowered antioxidant enzyme activity, e.g. glutathione peroxidase (GPX), is another hallmark of depression. The abovementioned lowered antioxidant capacity may impair protection against reactive oxygen species (ROS), causing damage to fatty acids, proteins and DNA by oxidative and nitrosative stress (O&NS). Increased ROS in depression is demonstrated by increased levels of plasma peroxides and xanthine oxidase. Damage caused by O&NS is shown by increased levels of malondialdehyde (MDA), a by-product of polyunsaturated fatty acid peroxidation and arachidonic acid; and increased 8-hydroxy-2-deoxyguanosine, indicating oxidative DNA damage. There is also evidence in major depression, that O&NS may have changed inactive autoepitopes to neoantigens, which have acquired immunogenicity and serve as triggers to bypass immunological tolerance, causing (auto)immune responses. Thus, depression is accompanied by increased levels of plasma IgG antibodies against oxidized LDL; and increased IgM-mediated immune responses against membrane fatty acids, like phosphatidyl inositol (Pi); oleic, palmitic, and myristic acid; and NO modified amino-acids, e.g. NO-tyrosine, NO-tryptophan and NO-arginine; and NO-albumin. There is a significant association between depression and polymorphisms in O&NS genes, like manganese superoxide dismutase, catalase, and myeloperoxidase. Animal models of depression very consistently show lowered antioxidant defences and activated O&NS pathways in the peripheral blood and the brain. In animal models of depression, antidepressants consistently increase lowered antioxidant levels and normalize the damage caused by O&NS processes. Antioxidants, such as N-acetyl-cysteine, compounds that mimic GPX activity, and zinc exhibit antidepressive effects. This paper reviews the pathways by which lowered antioxidants and O&NS may contribute to depression, and the (neuro)degenerative processes that accompany that illness. It is concluded that aberrations in O&NS pathways are--together with the inflammatory processes--key components of depression. All in all, the results suggest that depression belongs to the spectrum of (neuro)degenerative disorders.

An intriguing and hitherto unexplained co-occurrence: Depression and chronic fatigue syndrome are manifestations of shared inflammatory, oxidative and nitrosative (IO&NS) pathways

There is a significant 'comorbidity' between depression and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Depressive symptoms frequently occur during the course of ME/CFS. Fatigue and somatic symptoms (F&S), like pain, muscle tension, and a flu-like malaise, are key components of depression. At the same time, depression and ME/CFS show major clinical differences, which allow to discriminate them with a 100% accuracy. This paper aims to review the shared pathways that underpin both disorders and the pathways that discriminate them. Numerous studies have shown that depression and ME/CFS are characterized by shared aberrations in inflammatory, oxidative and nitrosative (IO&NS) pathways, like systemic inflammation and its long-term sequels, including O&NS-induced damage to fatty acids, proteins and DNA; dysfunctional mitochondria; lowered antioxidant levels, like zinc and coenzyme Q10; autoimmune responses to neoepitopes formed by O&NS; lowered omega-3 polyunsaturated fatty acid levels; and increased translocation of gram-negative bacteria. Some IO&NS-related pathways, like the induction of indoleamine 2-3-dioxygenase, neurodegeneration and decreased neurogenesis, are more specific to depression, whereas other pathways, like the 2'-5' oligoadenylate synthetase/RNase L pathway, are specific to ME/CFS. Most current animal models of depression, e.g. those induced by cytokines, are not reminiscent of human depression but reflect a mixture of depressive and F&S symptoms. The latter symptoms, sometimes called sickness behavior, differ from depression and ME/CFS because the former is a (sub)acute response to infection-induced pro-inflammatory cytokines that aims to enhance recovery, whereas the latter are characterized by long-term sequels in multiple IO&NS pathways. Depression and ME/CFS are not 'comorbid' disorders, but should be regarded as 'co-associated disorders' that are clinical manifestations of shared pathways.

Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients

There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders.

The NMDA receptor/nitric oxide pathway: a target for the therapeutic and toxic effects of lithium

Although lithium has largely met its initial promise as the first drug discovered in the modern era of psychopharmacology, to date no definitive mechanism for its effects has been established. It has been proposed that lithium exerts its therapeutic effects by interfering with signal transduction through G-protein-coupled receptor (GPCR) pathways or direct inhibition of specific targets in signaling systems, including inositol monophosphatase and glycogen synthase kinase-3 (GSK-3). Recently, increasing evidence has suggested that N-methyl-D-aspartate receptor (NMDAR)/nitric oxide (NO) signaling could mediate some lithium-induced responses in the brain and peripheral tissues. However, the probable role of the NMDAR/NO system in the action of lithium has not been fully elucidated. In this review, we discuss biochemical, preclinical/behavioral and physiological evidence that implicates NMDAR/NO signaling in the therapeutic effect of lithium. NMDAR/NO signaling could also explain some of side effects of lithium.