Prevention of oxidative stress-mediated neuropathology and improved clinical outcome by adjunctive use of a combination of antioxidants and omega-3 fatty acids in schizophrenia

Insights into the schizophrenia and dental care: focusing on interaction between implant treatments and oxidative stress

Schizophrenia is a complex mental condition characterized by the deterioration of thought processes and inappropriate emotional responses. Compared to the general population, individuals diagnosed with schizophrenia have an increased risk of developing various dental diseases, including dental caries, periodontal disease, oral mucosal diseases, and conditions associated with oral resonance. In this context, we propose to establish links between schizophrenia and dental illness, emphasizing the importance of oxidative stress (OS) markers in schizophrenia, and also the role of dental treatments, particularly dental implants. This highlights the urgent need for an intervention program to improve oral health in patients with schizophrenia, including aspects such as prevention and prosthetic treatment. Dental implants can be a favorable option, offering good aesthetic and functional results for treated patients with schizophrenia. Additionally, a carefully developed surgical plan is essential, requiring collaboration between psychiatry, oral and maxillofacial surgery, anesthesiology, and prosthodontics departments.

The importance of oxidative biomarkers in diagnosis, treatment, and monitoring schizophrenia patients

INTRODUCTION

The etiology of schizophrenia (SCZ), an incredibly complex disorder, remains multifaceted. Literature suggests the involvement of oxidative stress (OS) in the pathophysiology of SCZ.

OBJECTIVES

Determination of selected OS markers and brain-derived neurotrophic factor (BDNF) in patients with chronic SCZ and those in states predisposing to SCZ-first episode psychosis (FP) and ultra-high risk (UHR).

MATERIALS AND METHODS

Determination of OS markers and BDNF levels by spectrophotometric methods and ELISA in 150 individuals (116 patients diagnosed with SCZ or in a predisposed state, divided into four subgroups according to the type of disorder: deficit schizophrenia, non-deficit schizophrenia, FP, UHR). The control group included 34 healthy volunteers.

RESULTS

Lower activities of analyzed antioxidant enzymes and GSH and TAC concentrations were found in all individuals in the study group compared to controls (p < 0.001). BDNF concentration was also lower in all groups compared to controls except in the UHR subgroup (p = 0.01). Correlations were observed between BDNF, R-GSSG, GST, GPx activity, and disease duration (p < 0.02). A small effect of smoking on selected OS markers was also noted (rho<0.06, p < 0.03).

CONCLUSIONS

OS may play an important role in the pathophysiology of SCZ before developing the complete clinical pattern of the disorder. The redox imbalance manifests itself with such severity in individuals with SCZ and in a state predisposing to the development of this psychiatric disease that natural antioxidant systems become insufficient to compensate against it completely. The discussed OS biomarkers may support the SCZ diagnosis and predict its progression.

Mitigating Traumatic Brain Injury: A Narrative Review of Supplementation and Dietary Protocols

Traumatic brain injuries (TBIs) constitute a significant public health issue and a major source of disability and death in the United States and worldwide. TBIs are strongly associated with high morbidity and mortality rates, resulting in a host of negative health outcomes and long-term complications and placing a heavy financial burden on healthcare systems. One promising avenue for the prevention and treatment of brain injuries is the design of TBI-specific supplementation and dietary protocols centred around nutraceuticals and biochemical compounds whose mechanisms of action have been shown to interfere with, and potentially alleviate, some of the neurophysiological processes triggered by TBI. For example, evidence suggests that creatine monohydrate and omega-3 fatty acids (DHA and EPA) help decrease inflammation, reduce neural damage and maintain adequate energy supply to the brain following injury. Similarly, melatonin supplementation may improve some of the sleep disturbances often experienced post-TBI. The scope of this narrative review is to summarise the available literature on the neuroprotective effects of selected nutrients in the context of TBI-related outcomes and provide an evidence-based overview of supplementation and dietary protocols that may be considered in individuals affected by-or at high risk for-concussion and more severe head traumas. Prophylactic and/or therapeutic compounds under investigation include creatine monohydrate, omega-3 fatty acids, BCAAs, riboflavin, choline, magnesium, berry anthocyanins, Boswellia serrata, enzogenol, N-Acetylcysteine and melatonin. Results from this analysis are also placed in the context of assessing and addressing important health-related and physiological parameters in the peri-impact period such as premorbid nutrient and metabolic health status, blood glucose regulation and thermoregulation following injury, caffeine consumption and sleep behaviours. As clinical evidence in this research field is rapidly emerging, a comprehensive approach including appropriate nutritional interventions has the potential to mitigate some of the physical, neurological, and emotional damage inflicted by TBIs, promote timely and effective recovery, and inform policymakers in the development of prevention strategies.

Association of impulsive behavior and cerebrospinal fluid/plasma oxidation and antioxidation ratio in Chinese men

OBJECTIVES

Impulsive behavior is the precursor of many psychiatric and neurological conditions. High levels of impulsive behavior will increase health risk behavior and related injuries. Impulsive behavior is produced and regulated by central and peripheral biological factors, and oxidative stress (OS) can aggravate it. However, previous studies only showed that impulsive behavior was related to the level of the peripheral OS. Therefore, this study aims to clarify the relationship between OS and impulsive behavior in the brain and peripheral blood.

METHODS

We recruited 64 Chinese men. We measured superoxide dismutase (SOD) (including copper, zinc and manganese) and nitric oxide synthase (NOS) (including total, inducible and constitutive) in cerebrospinal fluid (CSF) and plasma. The Barratt Impulsiveness Scale version 11 (BIS-11) was used to evaluate impulsive behavior. The relationship between OS and impulsive behavior was evaluated by partial correlation analysis and stepwise multiple regression analysis.

RESULTS

Partial correlation analysis showed that the ratio of total NOS-to-MnSOD and iNOS-to-MnSOD in CSF were negatively correlated with the BIS-11 motor scores (r = -0.431, p = -0.001; r = -0.434, p = -0.001). Stepwise multiple regression analysis showed that the ratio of CSF iNOS-to-MnSOD was the most influential variable on the BIS-11 motor scores(β = -0.434, t = -3.433, 95 %CI(-0.374, -0.098), p = 0.001).

CONCLUSIONS AND RELEVANCE

The imbalance of central oxidation and antioxidation is related to impulsive behavior, which broadens our understanding of the correlation between impulsive behavior and OS.

Sunset Yellow induced biochemical and histopathological alterations in rat brain sub-regions

Sunset Yellow, a synthetic orange azo food dye was examined in this study for its impact on the Wistar rat brain sub-regions. The dye was administered orally to weanling rats at the Acceptable Daily Intake level (4 mg/kg/bw) for 40 days, and brain sub-regions viz., frontal cortex, cerebellum and hippocampus were examined for biochemical and histopathological changes. The results showed a significant decrease in tissue protein levels, superoxide dismutase, and catalase activity, as well as a significant increase in lipid peroxide levels in all brain sub-regions. Glutathione-S-transferase and Glutathione Reductase activities decreased, while Glutathione peroxidase activity increased. The biogenic amine levels and Acetylcholinesterase activity were also altered, with the frontal cortex and hippocampus being the most affected. Additionally, the dye caused histopathological damage in all brain sub-regions examined. This study indicates that the ADI level of Sunset Yellow may adversely affect brain tissue by causing oxidative damage.

Total antioxidant capacity, obesity and clinical correlates in first-episode and drug-naïve patients with schizophrenia

BACKGROUND

Overweight/obesity is a growing concern in schizophrenia (SZ). A few studies have shown that excessive oxidative stress and abnormal antioxidants were associated with pathogenesis and psychiatric symptoms in first episode antipsychotics naïve (FEAN) patients with SZ. However, there is no study has explored the interrelationships between total antioxidant status (TAS) and the severity of psychiatric symptoms in the early stage of SZ. This study aimed to evaluate the impact of overweight/obesity on psychiatric symptoms in FEAN patients with SZ.

METHODS

A total of 241 patients with FEAN SZ and 119 healthy controls were recruited and symptoms were evaluated by the Positive and Negative Syndrome Scale (PANSS). TAS levels were also measured in patients and healthy controls.

RESULTS

We found a significant negative association between body mass index (BMI) and TAS in FEAN patients, but not in controls. In addition, BMI and TAS were negatively associated with psychiatric symptoms. Interestingly, further regression analysis revealed that the interaction between BMI and TAS was associated with the negative symptoms in the early stage of SZ.

CONCLUSIONS

Our study indicates that abnormal TAS levels interacting with overweight/obesity may be involved in the pathophysiology of SZ, in particular negative symptoms.

Comparative Analysis of the Pre- and Post-Medication Effects of Antipsychotic Agents on the Blood-Based Oxidative Stress Biomarkers in Patients with Schizophrenia: A Meta-Analysis

OBJECTIVE

Studies have shown that oxidative stress (OS) is related to the pathophysiology of schizophrenia (SCZ), but whether antipsychotics can induce OS has not been investigated well. Moreover, antipsychotics have differential effects on the OS level modulation, i.e., different types of antipsychotics have different effects on the cellular antioxidants or pro-oxidants.

METHODS

We followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and investigated the OS indicators including both enzymatic and nonenzymatic markers, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA), glutathione (GSH), vitamin C, etc., of SCZ patients at baseline and follow-up of mono-medication.

RESULTS

Twenty studies met the inclusion criteria, with a total of 1162 patients enrolled at baseline, and 1105 patients completed the follow-up. OS markers were changed after a period of antipsychotic treatment in SCZ patients. The GPx activity and MDA level decreased in the whole blood (P<0.05), also the serum MDA level decreased (P<0.05). For the first-episode SCZ patients, the activity of GPx and the level of MDA decreased, while the level of vitamin C increased (all P<0.05). The levels of MDA in patients receiving atypical antipsychotics decreased (P<0.05), while the level of GSH in patients with typical antipsychotics decreased (P=0.05).

CONCLUSION

Antipsychotic medication may cause changes in the levels of OS markers in different blood samples of SCZ patients. However, the available studies might not be sufficient to reveal the underlying facts accurately due to the poor quality of experimental designs in the published literature.

Adenosine, Schizophrenia and Cancer: Does the Purinergic System Offer a Pathway to Treatment?

For over a century, a complex relationship between schizophrenia diagnosis and development of many cancers has been observed. Findings from epidemiological studies are mixed, with reports of increased, reduced, or no difference in cancer incidence in schizophrenia patients. However, as risk factors for cancer, including elevated smoking rates and substance abuse, are commonly associated with this patient population, it is surprising that cancer incidence is not higher. Various factors may account for the proposed reduction in cancer incidence rates including pathophysiological changes associated with disease. Perturbations of the adenosine system are hypothesized to contribute to the neurobiology of schizophrenia. Conversely, hyperfunction of the adenosine system is found in the tumor microenvironment in cancer and targeting the adenosine system therapeutically is a promising area of research in this disease. We outline the current biochemical and pharmacological evidence for hypofunction of the adenosine system in schizophrenia, and the role of increased adenosine metabolism in the tumor microenvironment. In the context of the relatively limited literature on this patient population, we discuss whether hypofunction of this system in schizophrenia, may counteract the immunosuppressive role of adenosine in the tumor microenvironment. We also highlight the importance of studies examining the adenosine system in this subset of patients for the potential insight they may offer into these complex disorders.

Increased Markers of Oxidative Stress and Positive Correlation Low-Grade Inflammation with Positive Symptoms in the First Episode of Schizophrenia in Drug-Naïve Patients

Schizophrenia is a severe and chronic mental illness usually diagnosed in adolescents and young adults. Many studies indicate that oxidative stress causes membrane dysfunction and cell damage, which is implicated in the pathophysiology of schizophrenia. The purpose of our study was to evaluate oxidative stress markers (the main primary products of lipid peroxidation, lipid hydroperoxides (LOOH), and end products of lipid peroxidation, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and Ferric Reducing Ability of Plasma (FRAP)) in the plasma of patients with the first episode of schizophrenia in drug-naïve patients (22 men and 12 women aged 17-29). The control group (Ctrl) comprised 26 healthy subjects (19 men and 7 women, aged 18-30 years). The Positive and Negative Syndrome Scale (PANSS) was applied to evaluate psychotic symptoms. Analyses of the oxidative stress variables revealed an increased level of SOD (U/mL) in subjects with schizophrenia versus control group. In addition, lipid damage measured as LOOHs µ (mol/L) and MDA was significantly higher in patients with schizophrenia in comparison to control subjects. There was a positive correlation between MDA µmol/L and PANSS P and a positive correlation between C-reactive protein (CRP) and the PANSS P scale. The elevated level of superoxide dismutase in patients with the first episode of schizophrenia can be explained by compensatory mechanisms to counteract oxidative stress. Malondialdehyde can be used as a simple biomarker of low-grade systemic inflammation associated with oxidative stress. A positive correlation between CRP and PANSS P scale and MDA and PANSS P scale may indicate a significant relationship between the development of low-grade inflammation and damage associated with oxidative stress in the development of the first symptoms of schizophrenia.

Urinary biopyrrins and free immunoglobin light chains are biomarker candidates for screening at-risk mental state in adolescents

BACKGROUND

Early diagnosis of individuals' at-risk mental state (ARMS) is important for preventing their pathogenesis or, at least, delaying onset of overt psychosis. Traditional diagnosis of ARMS subjects is mainly based on structured interviews, but future diagnosis would be carried out together with biomarkers.

AIM

In this study, we report urinary biopyrrins and free immunoglobin light chains κ and λ (κFLC and λFLC) as novel diagnostic biomarker candidates for screening ARMS subjects.

METHODS

Nineteen ARMS subjects and 21 age- and sex-matched healthy controls were enrolled in this study. Inclusion criteria of the ARMS subjects were based on a comprehensive assessment of Structured Interview for Prodromal Syndromes. We compared oxidative stress and immunological markers in the urine of ARMS subjects with those of healthy controls by ELISA protocol.

RESULTS

Augmentation of biopyrrins and reduction of κFLC and λFLC were found in the ARMS samples, and their diagnostic performance was evaluated by receiver operating characteristic analysis, of which area under the curve was as large as 0.915 in combination.

CONCLUSION

Our findings suggest that the ARMS subjects were under higher oxidative stress but lower in B cell activation, and that the combined assay of urinary biopyrrins and free immunoglobulin light chains would be useful for the early detection and screening of ARMS subjects among adolescents.

Elevated activity of superoxide dismutase in male late-life schizophrenia and its correlation with clinical symptoms and cognitive deficits

BACKGROUND

Despite inconsistent findings, accumulative evidence has shown abnormalities of the key antioxidant enzyme, superoxide dismutase (SOD), in patients with schizophrenia. However, few studies explored SOD in late-life schizophrenia (LLS). Our work aimed to investigate changes in SOD activity and the relationship between SOD activity and psychotic symptoms or cognitive deficits in LLS.

METHODS

32 geriatric male patients with schizophrenia (age ≥ 60) and 28 age-matched male normal controls were recruited in the study. We assessed cognitive functions with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), evaluated the severity of clinical symptoms with the Positive and Negative Syndrome Scale (PANSS), and measured the plasma levels of SOD.

RESULTS

Patients with LLS presented with higher total levels of SOD compared to the controls (81.70 vs. 65.26 U/ml, p < .001). Except for the visuospatial index, the cognitive performance was significantly worse on RBANS total and other domain scores in the schizophrenia group than the control group. In the schizophrenia group, SOD levels were positively correlated with subscores of general psychopathology and negative symptoms and total scores of the PANSS (all p < .05), and inversely associated with performance in immediate memory, language, and RBANS total scores (all p < .05).

CONCLUSIONS

Our findings suggest that patients with LLS display disturbances in the antioxidant system, which may underlie the pathological process of cognitive impairments and negative symptoms in the late stage of schizophrenia. Supplementing with antioxidants could be a potential treatment.

The Impact of the Combined Administration of 1MeTIQ and MK-801 on Cell Viability, Oxidative Stress Markers, and Glutamate Release in the Rat Hippocampus

MK-801, as an N-methyl-D-aspartate (NMDA) receptor inhibitor, causes elevation in glutamate release, which may lead to an increase in excitotoxicity, oxidative stress and, consequently, cell death. 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) shows antioxidant activity. The aim of the present study was to evaluate the effect of combined treatment with 1MeTIQ and MK-801 on cell viability, antioxidant enzyme activity, and glutamate release in the rat hippocampus. Cytotoxicity was measured using lactate dehydrogenase leakage assay (LDH) and the methyl tetrazolium (MTT) assay; antioxidant enzyme activity (glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT)) were measured by ELISA kits. The release of glutamate in the rat hippocampus was measured using in vivo microdialysis methodology. An in vitro study showed that MK-801 induced cell death in a concentration-dependent manner and that 1MeTIQ partially reduced this adverse effect of MK-801. An ex vivo study indicated that MK-801 produced an increase in antioxidant enzyme activity (GPx, GR, and SOD), whereas coadministration of MK-801 and 1MeTIQ restored the activity of these enzymes to the control level. An in vivo microdialysis study demonstrated that combined treatment with both drugs decreased the release of glutamate in the rat hippocampus. The above results revealed that 1MeTIQ shows limited neuroprotective activity under conditions of glutamate-induced neurotoxicity.

Oxidative Stress and the Pathophysiology and Symptom Profile of Schizophrenia Spectrum Disorders

Schizophrenia is associated with increased levels of oxidative stress, as reflected by an increase in the concentrations of damaging reactive species and a reduction in anti-oxidant defences to combat them. Evidence has suggested that whilst not the likely primary cause of schizophrenia, increased oxidative stress may contribute to declining course and poor outcomes associated with schizophrenia. Here we discuss how oxidative stress may be implicated in the aetiology of schizophrenia and examine how current understanding relates associations with symptoms, potentially via lipid peroxidation induced neuronal damage. We argue that oxidative stress may be a good target for future pharmacotherapy in schizophrenia and suggest a multi-step model of illness progression with oxidative stress involved at each stage.

Plasma bilirubin levels are reduced in first-episode psychosis patients and associates to working memory and duration of untreated psychosis

Schizophrenia is a severe mental disorder and one of its characteristics is cognitive impairments. Findings regarding levels of the heme metabolite and plasma antioxidant bilirubin in schizophrenia are inconclusive. However, a recently published study indicate that low levels of bilirubin may be implicated in the memory impairments seen in the disorder. The aim of this cross-sectional study was to investigate the levels of bilirubin in individuals with a first-episode psychosis (FEP) and to examine if bilirubin levels were associated to cognitive impairments, symptoms and duration of untreated psychosis (DUP). Bilirubin levels were reduced in 39 individuals with FEP compared with 20 HC (median [IQR]: 11.0 [9.0-13.0] µM vs. 15.0 [11.5-18.5] µM). In individuals with FEP, bilirubin levels were also positively correlated to two working memory tests (r = 0.40 and r = 0.32) and inversely correlated to DUP (r = - 0.36). Findings were not influenced by confounding factors. The results confirm the antioxidant deficit previously seen in schizophrenia, but also indicate that these changes may be related to DUP. The study also confirms that bilirubin may be implicated in the cognitive deficits that accompanies the disorder, here for the first time presented in individuals with FEP.

Tetrahydrocannabinol-Rich Extracts From Cannabis Sativa L. Improve Glucose Consumption and Modulate Metabolic Complications Linked to Neurodegenerative Diseases in Isolated Rat Brains

Reduced brain glucose consumption arising from impaired glucose uptake and utilization has been linked to the pathogenesis and complications of neurodegenerative diseases. The ability of Cannabis sativa L. tetrahydrocannabinol (THC)-rich extracts to stimulate brain glucose uptake and utilization as well as its modulatory effect on gluconeogenesis, antioxidative, purinergic and cholinergic activities were investigated in isolated rats’ brains. C. sativa leaves were sequentially extracted to yield the hexane and dichloromethane extracts. The extracts were incubated at 37°C with freshly harvested brains in the presence of glucose for 2 h. The control consisted of incubation without the extracts, while brains without the extracts and glucose served as the normal control. Metformin was used as the standard drug. C. sativa extracts caused a significant (p < 0.05) increase in brain glucose uptake, with concomitant elevation of glutathione level, superoxide dismutase, catalase, and ecto-nucleoside triphosphate diphosphohydrolase activities compared to the controls. Incubation with C. sativa extracts also led to depletion in malondialdehyde and nitric oxide levels, acetylcholinesterase, butyrylcholinesterase, glucose 6-phosphatase and fructose-1,6-biphosphatase activities. GC-MS analysis of the extracts revealed the presence of THC. In silico analysis predicted THC to be permeable across the blood-brain-barrier. THC was also predicted to have an oral LD₅₀ and toxicity class values of 482 mg/kg and 4 respectively. These results indicate that C. sativa improves glucose consumption with concomitant suppression of oxidative stress and cholinergic dysfunction, and modulation of purinergic and gluconeogenic activities in brain tissues

Regulation of Reactive Oxygen Species-Mediated Damage in the Pathogenesis of Schizophrenia

The biochemical integrity of the brain is paramount to the function of the central nervous system, and oxidative stress is a key contributor to cerebral biochemical impairment. Oxidative stress, which occurs when an imbalance arises between the production of reactive oxygen species (ROS) and the efficacy of the antioxidant defense mechanism, is believed to play a role in the pathophysiology of various brain disorders. One such disorder, schizophrenia, not only causes lifelong disability but also induces severe emotional distress; however, because of its onset in early adolescence or adulthood and its progressive development, consuming natural antioxidant products may help regulate the pathogenesis of schizophrenia. Therefore, elucidating the functions of ROS and dietary antioxidants in the pathogenesis of schizophrenia could help formulate improved therapeutic strategies for its prevention and treatment. This review focuses specifically on the roles of ROS and oxidative damage in the pathophysiology of schizophrenia, as well as the effects of nutrition, antipsychotic use, cognitive therapies, and quality of life on patients with schizophrenia. By improving our understanding of the effects of various nutrients on schizophrenia, it may become possible to develop nutritional strategies and supplements to treat the disorder, alleviate its symptoms, and facilitate long-term recovery.

Activity of Lysosomal Enzymes During Protein Malnutrition and Progesterone Supplementation in the Mouse

This study investigated the effects of protein malnutrition and progesterone supplementation on the activities of a spectrum of lysosomal enzymes in tissue fragments of mouse liver and kidney. The working hypothesis was that the known anti-stress action of progesterone could have to do with the inhibition of lysosomes which are engaged in apoptotic and oxidative stress-induced responses. The study investigated the effects of exogenous progesterone in chronically (3 weeks) protein-malnourished (10% protein) mice on the activities of lysosomal hydrolases in liver and kidney tissues. Progesterone was injected intraperitoneally in a dose of 2 μg/g body mass dissolved in a vehicle volume of 10 μL/g body mass during the final 3 days of exposure to either low 10% or standard 16% protein content in the chow. After euthanizing the animals, tissue fragments of liver and kidney assayed for the content of lysosomal enzymes. The results demonstrated the stimulating effect of protein malnutrition on lysosomal activities. We further found, contrary to our hypothesis, that progesterone supplementation during both standard and low-protein conditions enhanced lysosomal activities, particularly acting in concert with protein malnutrition in kidney tissue. The effects were selective concerning both lysosomal enzymes and tissues and of highly variable magnitude. Nonetheless, we believe we have shown that progesterone assists protein malnutrition in stimulation of lysosomal enzymes, which suggests the possibility of the hormone's engagement in cleansing the cellular milieu in disorders consisting of accumulation of toxic molecules.

Mitochondrial electron transport chain, ROS generation and uncoupling (Review)

The mammalian mitochondrial electron transport chain (ETC) includes complexes I-IV, as well as the electron transporters ubiquinone and cytochrome c. There are two electron transport pathways in the ETC: Complex I/III/IV, with NADH as the substrate and complex II/III/IV, with succinic acid as the substrate. The electron flow is coupled with the generation of a proton gradient across the inner membrane and the energy accumulated in the proton gradient is used by complex V (ATP synthase) to produce ATP. The first part of this review briefly introduces the structure and function of complexes I-IV and ATP synthase, including the specific electron transfer process in each complex. Some electrons are directly transferred to O₂ to generate reactive oxygen species (ROS) in the ETC. The second part of this review discusses the sites of ROS generation in each ETC complex, including sites I_F and I_Q in complex I, site II_F in complex II and site III_Qo in complex III, and the physiological and pathological regulation of ROS. As signaling molecules, ROS play an important role in cell proliferation, hypoxia adaptation and cell fate determination, but excessive ROS can cause irreversible cell damage and even cell death. The occurrence and development of a number of diseases are closely related to ROS overproduction. Finally, proton leak and uncoupling proteins (UCP_S) are discussed. Proton leak consists of basal proton leak and induced proton leak. Induced proton leak is precisely regulated and induced by UCPs. A total of five UCPs (UCP1-5) have been identified in mammalian cells. UCP1 mainly plays a role in the maintenance of body temperature in a cold environment through non-shivering thermogenesis. The core role of UCP2-5 is to reduce oxidative stress under certain conditions, therefore exerting cytoprotective effects. All diseases involving oxidative stress are associated with UCPs.

Serum Oxidative Stress Marker Levels in Unmedicated and Medicated Patients with Schizophrenia

Oxidative stress has been suggested to be involved in schizophrenia, but studies have demonstrated inconsistent results on oxidative stress marker level/activity in patients with schizophrenia. In order to clarify the circulating oxidative stress marker level/activity in patients with schizophrenia, this study recruited 80 schizophrenia patients (40 first-episode, drug-free and 40 chronically medicated patients) and 80 controls to analyze serum activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), and levels of lipid peroxidation marker malondialdehyde (MDA) in schizophrenia patients, and whether they associate with the severity of the disease. We showed that only serum GSH-Px activity was significantly reduced in unmedicated patients with schizophrenia when compared with control subjects, whereas the other three analyzed oxidative stress markers did not show significant differences between cases and controls. Moreover, our results demonstrated that chronic medication increased GSH-Px activity and MDA levels in patients with schizophrenia, but reduced SOD activity in the patients. We also found that short-term antipsychotic treatments on the patients with schizophrenia reduced the SOD activity. Correlation analyses indicated that the oxidative stress marker activity/level is not significantly associated with the severity of schizophrenia, except that SOD level correlated with PANSS positive score significantly. Taken together, the data from the present study suggested that the dysfunctions of oxidative stress markers in patients with schizophrenia were mainly caused by antipsychotics, emphasizing increased oxidative stress as a potential side effect of antipsychotics on the patients.

Disturbed glutathione antioxidative defense is associated with structural brain changes in neuroleptic-naïve first-episode psychosis patients

BACKGROUND

Oxidative stress and impaired antioxidant defense are reported in schizophrenia and are thought to be associated with disturbed neurodevelopment, brain structural alterations, glutamatergic imbalance, negative symptomatology, and cognitive impairment. To test some of these assumptions we investigated the glutathione (GSH) antioxidant defense system (AODS) and brain structural abnormalities in drug-naïve individuals with first acute episode of psychosis (FEP).

METHOD

The study involved 27 drug-naïve FEP patients and 31 healthy controls (HC). GSH AODS markers and TBARS (thiobarbituric acid reactive substances) were measured in blood plasma and erythrocytes. High-resolution T₁-weighted 3T MRI were acquired from all subjects. To investigate brain structural abnormalities and effects of illness on interactions between GSH metabolites or enzyme activities and local grey matter density, voxel-based morphometry (VBM) with the computational anatomy toolbox (CAT12) was used. Symptomatology was assessed using the Positive and Negative Syndrome Scale (PANSS) and the Symptom Checklist 1990 revised (SCL-90-R).

RESULTS

(i) In FEP patients, glutathione reductase activity (GSR) was lower than in the HC group. GSR activity in plasma was inversely correlated with SCL-90-R scores of depression and PANSS scores of the negative symptom subscale. (ii) A reduction of GM was observed in left inferior frontal, bilateral temporal, as well as parietal cortices of FEP patients. (iii) Interaction analyses revealed an influence of illness on GSR/GM associations in the left orbitofrontal cortex (BA 47).

CONCLUSION

Our findings support the notion of altered GSH antioxidative defense in untreated acute psychosis as a potential pathomechanism for localized brain structural abnormalities. This pathology relates to a key brain region of social cognition, affective motivation control and decision making, and is clinically accompanied by depressive and negative symptoms.

Dietary glucoraphanin prevents the onset of psychosis in the adult offspring after maternal immune activation

Maternal immune activation (MIA) contributes to behavioral abnormalities relevant to schizophrenia in adult offspring, although the molecular mechanisms underlying MIA-induced behavioral changes remain unclear. Here we demonstrated that dietary intake of glucoraphanin (GF), the precursor of a natural antioxidant sulforaphane, during juvenile and adolescent stages prevented cognitive deficits and loss of parvalbumin (PV) immunoreactivity in the medial prefrontal cortex (mPFC) of adult offspring after MIA. Gene set enrichment analysis by RNA sequencing showed that MIA caused abnormal expression of centrosome-related genes in the PFC and hippocampus of adult offspring, and that dietary intake of GF improved these abnormal gene expressions. Particularly, MIA increased the expression of suppressor of fermentation-induced loss of stress resistance protein 1 (Sfi1) mRNA in the PFC and hippocampus of adult offspring, and dietary intake of GF prevented the expression of Sfi1 mRNA in these regions. Interestingly, we found altered expression of SFI1 in the postmortem brains and SFI1 mRNA in hair follicle cells from patients with schizophrenia compared with controls. Overall, these data suggest that centrosome-related genes may play a role in the onset of psychosis in offspring after MIA. Therefore, dietary intake of GF-rich vegetables in high-risk psychosis subjects may prevent the transition to psychosis in young adulthood.

Antioxidant and anti-inflammatory nutrient status, supplementation, and mechanisms in patients with schizophrenia

Over 50 million people around the world suffer from schizophrenia, a severe mental illness characterized by misinterpretation of reality. Although the exact causes of schizophrenia are still unknown, studies have indicated that inflammation and oxidative stress may play an important role in the etiology of the disease. Pro-inflammatory cytokines are crucial for normal central nervous development and proper functioning of neural networks and neurotransmitters. Patients with schizophrenia tend to have abnormal immune activation resulting in elevated pro-inflammatory cytokine levels, ultimately leading to functional brain impairments. Patients with schizophrenia have also been found to suffer from oxidative stress, a result of an imbalance between the production of free radicals and the ability to detoxify their harmful effects. Furthermore, inflammation and oxidative stress are implicated to be related to the severity of psychotic symptoms. Several nutrients are known to have anti-inflammatory and antioxidant functions through various mechanisms in our body. The present review evaluates studies and literature that address the status and supplementation of omega-3 polyunsaturated fatty acids, vitamin D, B vitamins (B6, folate, B12), vitamin E, and carotenoids in different stages of schizophrenia. The possible anti-inflammatory and antioxidant mechanisms of action of each nutrient are discussed.

The Antipsychotic Effects of Omega-3 Fatty Acids in Rats

BACKGROUND

In humans, omega-3 fatty acids are necessary for cell membranes, brain function and nerve transmission continuation. When animals are exposed to a new environment-or as a result of an apomorphine application that creates an agonistic effect on D1 and D2 receptors-they display behavioral reactions like rearing and stereotypy. This study aims to reveal the possible antipsychotic and oxidative effects of omega-3 fatty acids by comparing with chlorpromazine, a conventional antipsychotic drug, through evaluating the novelty-induced rearing and apomorphine-induced stereotypic behaviors, as well as malondialdehyde and glutathione levels in rats.

METHODS

Twenty-eight, adult, male, Wistar rats were used in the study. Briefly, 4 groups of rats (n = 7) were administered docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA) (300 mg/kg; DHA: 120 mg/kg + EPA: 180 mg/kg intraperitoneally [IP]), DHA + EPA (150 mg/kg; DHA: 60 mg/kg + EPA: 90 mg/kg IP), chlorpromazine (1 mg/kg, IP) and isotonic saline (1 mL/kg, IP). One hour later, apomorphine (2 mg/kg, subcutaneously) was administered to each rat. After the apomorphine administration, rats were observed for stereotypic behavior.

RESULTS

This study shows that omega-3 fatty acids, "similar to antipsychotics," reversed the psychotic like effects, increase of oxidants and decrease of antioxidants that are composed experimentally in rats.

CONCLUSIONS

The application of omega-3 fatty acids has antipsychotic effects and causes an oxidative imbalance. This study adds new evidence to the current literature regarding the possible antipsychotic effects of omega-3 fatty acids.

First-episode psychosis is associated with oxidative stress: Effects of short-term antipsychotic treatment

AIMS

In the present study, our aim was to investigate the oxidative-antioxidative systems in unmedicated first-episode psychosis (FEP) patients at the beginning and after short-term treatment.

METHODS

This study consisted of 29 patients who experienced an FEP and 25 control subjects. In order to investigate the oxidative status, we determined plasma malondialdehyde (MDA) levels, oxidizability of red blood cells, oxidation and oxidizability of apolipoprotein B-containing lipoproteins (apo B-basal MDA and apo B-ΔMDA). In order to evaluate the antioxidative defense, we measured serum total antioxidative capacity, uric acid, albumin, total bilirubin and vitamin E levels and serum paraoxonase/arylesterase, whole blood glutathione peroxidase (GPx) and red blood cell superoxide dismutase activities before and after 6 weeks of treatment in patients with FEP.

RESULTS

Plasma MDA and apo B-basal MDA levels and red blood cell superoxide dismutase activity were significantly higher and serum arylesterase and whole blood-GPx activities were lower in the FEP group than those of the healthy control group. There were not any significant changes in the oxidative and antioxidative system parameters (except increased vitamin E levels) after treatment.

CONCLUSIONS

The results of this study suggest that FEP is accompanied by oxidative stress. However, further studies are needed to clarify the role of oxidative stress in the physiopathologic mechanisms of FEP, so that oxidative and antioxidative system parameters can be used in the management of these patients. In accordance with psychiatric evaluation, for a better management, patients with FEP may require a multidisciplinary approach, including oxidative and antioxidative system parameters.

Effects of omega-3 PUFA on the vitamin E and glutathione antioxidant defense system in individuals at ultra-high risk of psychosis

BACKGROUND

Oxidative stress and impaired antioxidant defenses are reported in schizophrenia and are associated with disturbed neurodevelopment, brain structural alterations, glutamatergic imbalance, increased negative symptoms, and cognitive impairment. There is evidence that oxidative stress predates the onset of acute psychotic illness. Here, we investigate the effects of omega-3 PUFA on the vitamin E and glutathione antioxidant defense system (AODS).

METHOD

In 64 help-seeking UHR-individuals (13-25 years of age), vitamin E levels and glutathione were investigated before and after 12 weeks of treatment with either 1.2g/d omega-3 (PUFA-E) or saturated fatty acids (SFA-E), with each condition also containing 30.4mg/d alpha-tocopherol to ensure absorption without additional oxidative risk.

RESULTS

In multivariate tests, the effects on the AODS (alpha-tocopherol, total glutathione) were not significantly different (p=0.13, p=0.11, respectively) between treatment conditions. According to univariate findings, only PUFA-E caused a significant alpha-tocopherol increase, while PUFA-E and SFA-E caused a significant gamma- and delta-tocopherol decrease. Total glutathione (GSHt) was decreased by PUFA-E supplementation.

CONCLUSION

Effects of the PUFA-E condition on the vitamin E and glutathione AODS could be mechanisms underlying its clinical effectiveness. In terms of the vitamin E protection system, PUFA-E seems to directly support the antioxidative defense at membrane level. The effect of PUFA-E on GSHt is not yet fully understood, but could reflect antioxidative effects, resulting in decreased demand for glutathione. It is still necessary to further clarify which type of PUFA/antioxidant combination, and in which dose, is effective at each stage of psychotic illness.

Neurodevelopmental Animal Models Reveal the Convergent Role of Neurotransmitter Systems, Inflammation, and Oxidative Stress as Biomarkers of Schizophrenia: Implications for Novel Drug Development

Schizophrenia is a life altering disease with a complex etiology and pathophysiology, and although antipsychotics are valuable in treating the disorder, certain symptoms and/or sufferers remain resistant to treatment. Our poor understanding of the underlying neuropathological mechanisms of schizophrenia hinders the discovery and development of improved pharmacological treatment, so that filling these gaps is of utmost importance for an improved outcome. A vast amount of clinical data has strongly implicated the role of inflammation and oxidative insults in the pathophysiology of schizophrenia. Preclinical studies using animal models are fundamental in our understanding of disease development and pathology as well as the discovery and development of novel treatment options. In particular, social isolation rearing (SIR) and pre- or postnatal inflammation (PPNI) have shown great promise in mimicking the biobehavioral manifestations of schizophrenia. Furthermore, the "dual-hit" hypothesis of schizophrenia states that a first adverse event such as genetic predisposition or a prenatal insult renders an individual susceptible to develop the disease, while a second insult (e.g., postnatal inflammation, environmental adversity, or drug abuse) may be necessary to precipitate the full-blown syndrome. Animal models that emphasize the "dual-hit" hypothesis therefore provide valuable insight into understanding disease progression. In this Review, we will discuss SIR, PPNI, as well as possible "dual-hit" animal models within the context of the redox-immune-inflammatory hypothesis of schizophrenia, correlating such changes with the recognized monoamine and behavioral alterations of schizophrenia. Finally, based on these models, we will review new therapeutic options, especially those targeting immune-inflammatory and redox pathways.

A randomized, controlled trial of omega-3 fatty acids plus an antioxidant for relapse prevention after antipsychotic discontinuation in first-episode schizophrenia

BACKGROUND

While antipsychotics are effective in the maintenance treatment of schizophrenia they have safety and tolerability risks. We investigated whether a combination of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and a metabolic antioxidant, alpha-lipoic acid (α-LA), is effective in preventing relapse after antipsychotic discontinuation in subjects who were successfully treated for 2-3 years after a first-episode of schizophrenia, schizo-affective or schizophreniform disorder.

METHODS

In this randomized, double-blind, placebo controlled study antipsychotic treatment was tapered and discontinued and participants received either ω-3 PUFAs (eicosapentaenoic acid 2g/day and docosahexaenoic acid 1g/day)+α-LA 300 mg/day or placebo. Subjects were followed up for two years, or until relapse.

RESULTS

Recruitment was terminated prematurely due to the high relapse rates in both treatment groups as well as the severity of some of the relapse episodes. Of the 33 participants, 19/21(90%) randomized to ω-3 PUFAs+α-LA relapsed and one (5%) completed two years without relapse (p=0.6); and 9/12 (75%) randomized to placebo relapsed and none completed two years without relapse. Mean times to relapse were 39.8 ± 25.4 and 38.3 ± 26.6 weeks for the ω-3 PUFAs+α-LA and placebo groups, respectively (p=0.9). There were no significant differences between the groups in relapse symptom severity.

CONCLUSIONS

We found no evidence that ω-3 PUFAs+α-LA could be a suitable alternative to maintenance antipsychotic treatment in relapse prevention, in this small study. Antipsychotic discontinuation after a single episode of schizophrenia carries a very high risk of relapse, and treatment guidelines endorsing this practice should be revised.

Basal low antioxidant capacity correlates with cognitive deficits in early onset psychosis. A 2-year follow-up study

The objective of the study is to examine the association of baseline total antioxidant status (TAS) and glutathione (GSH) levels with short- and long-term cognitive functioning in patients with early onset first-episode psychosis, comparing affective and non-affective psychoses. We analysed 105 patients with an early onset-first episode psychosis (age 9-17 years) and 97 healthy controls. Blood samples were taken at admission for measurement of TAS and GSH, and cognitive performance was assessed at baseline and at 2years of follow-up. Regression analysis was used to assess the relationship between TAS/GSH levels at baseline and cognitive performance at both time points, controlling for confounders. Baseline TAS and GSH levels were significantly lower in patients than healthy controls. In patients, baseline TAS was positively associated with the global cognition score at baseline (p=0.048) and two years later (p=0.005), while TAS was not associated with cognitive functioning in healthy controls. Further, baseline TAS in patients was specifically associated with the memory domain at baseline and with the memory and attention domains two years later. Stratifying by affective and non-affective psychoses, significant associations were only found between TAS and cognition in the non-affective psychosis group. Baseline GSH levels were not associated with cognitive functioning at either time point in either group. The antioxidant defence capacity in early onset first-episode psychotic patients is directly correlated with global cognition at baseline and at 2years of follow-up, especially in non-affective psychosis.

Oxidative status and the severity of clinical symptoms in patients with post-traumatic stress disorder

BACKGROUND

The aim of this study was to measure the parameters of oxidative stress in the blood of patients with post-traumatic stress disorder.

METHODS

The study included 80 male war veterans who participated actively in the Homeland war in Croatia. Volunteers were divided into two groups: 50 veterans diagnosed with post-traumatic stress disorder and 30 without diagnosis. The self-assessment Hospital Anxiety and Depression Scale and the Beck Depression Inventory were used to detect the severity of depression and anxiety in the post-traumatic stress disorder patients. Catalytic concentrations of superoxide dismutase and glutathione peroxidase in erythrocytes and the concentration of malondialdehyde in serum were measured spectrophotometrically.

RESULTS

Although the catalytic concentrations of erythrocyte superoxide dismutase and erythrocyte glutathione peroxidase were within the reference range for both groups, the values obtained for the post-traumatic stress disorder group were significantly lower (P<0.001). For serum malondialdehyde concentrations, no statistically significant differences between the groups were found.

CONCLUSIONS

Lower catalytic concentrations of erythrocyte superoxide dismutase and erythrocyte glutathione peroxidase in patients with post-traumatic stress disorder may indicate a weaker response to oxidative stress due to impaired enzyme activity and/or decreased synthesis. Conversely, no significant changes in serum malondialdehyde concentrations suggest a compensated balance and adaptive response to (oxidative) stress.

Neuroprotective efficacy of a combination of fish oil and ferulic acid against 3-nitropropionic acid-induced oxidative stress and neurotoxicity in rats: behavioural and biochemical evidence

The beneficial effects of fish oil (FO) supplements on the central nervous system have been adequately demonstrated. However, FO supplementation at higher doses for longer duration is likely to cause oxidative stress in vivo. To overcome this, attempts have been made to enrich FO with known antioxidants/phytochemicals. In the present study, we examined the hypothesis that a combination of FO with ferulic acid (FA), a naturally occurring phenolic compound, is likely to provide higher degree of neuroprotection. This was examined by employing 3-nitropropionic acid (NPA), a well-known neurotoxin used to mimic behavioural and neurochemical features of Huntington’s disease. Growing male rats administered with NPA (25 mg/kg of body weight (bw) for 4 days) were provided with either FO (2 mL/kg bw), FA (50 mg/kg bw) or FO+FA for 2 weeks. Interestingly, FO+FA not only offered significant protection against NPA-induced behavioural impairments, but also markedly attenuated oxidative stress in brain regions (striatum/cerebellum) as evidenced by the reduction in reactive species, malondialdehyde, hydroperoxides and nitric oxide (NO) levels. Further, FO+FA combination restored the activities of various antioxidant enzymes and the levels of cytosolic calcium. In striatum, activity levels of acetylcholinesterase enzyme and dopamine levels were markedly restored among FO+FA rats. Interestingly, NPA-induced mitochondrial dysfunctions were also attenuated among FO+FA rats. Collectively, our findings suggest the advantage of co-treatment of FO with known antioxidants to achieve a higher therapeutic benefit in the treatment of oxidative stress-mediated neurodegenerative conditions.

Seafood types and age-related cognitive decline in the Women's Health Study

BACKGROUND

Seafood consumption may prevent age-related cognitive decline. However, benefits may vary by nutrient contents in different seafood types. We examined associations between total seafood consumption and cognitive decline and whether these associations differ by seafood types.

METHODS

We conducted a prospective cohort study of 5,988 women (mean age, 72 years) from the Women's Health Study who self-reported seafood intake at Women's Health Study baseline and also participated in telephone assessments of general cognition, verbal memory, and category fluency administered 5.6 years after Women's Health Study baseline and 2 and 4 years thereafter. Primary outcomes were standardized composite scores of global cognition and verbal memory.

RESULTS

After adjusting for potential confounders, different amounts of total seafood consumption were not associated with changes in global cognition (p = .56) or verbal memory (p = .29). Considering seafood types, however, compared with women consuming less than once-weekly tuna or dark-meat finfish, those with once-weekly or higher consumption had significantly better verbal memory (0.079 standard units; p < .01) after 4 years-a difference comparable to that for women 2.1 years apart in age. There was also a statistically nonsignificant suggestion of better global cognition (p = .13) with once-weekly or higher tuna or dark-meat fish consumption. No significant associations were observed for light-meat finfish or shellfish.

CONCLUSIONS

The relation of seafood to cognition may depend on the types consumed. Total consumption levels of seafood were unrelated to cognitive change. However, consumption of tuna and dark-meat fish once weekly or higher was associated with lower decline in verbal memory for a period of 4 years.

Adaptive response in the antioxidant defence system in the course and outcome in first-episode schizophrenia patients: a 12-months follow-up study

Correlation of plasma antioxidant enzyme activity with the course and outcome in first-episode schizophrenia patients (n=49) was analyzed in order to assess the possible utility of peripheral markers of oxidative stress as prognostic factors. These markers were measured shortly after the onset of schizophrenia, and again 1, 6 and 12 months later. A decrease in catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and glutathione (GSH) levels and total antioxidant status (TAS), as well as an increase in thiobarbituric acid reactive substances (TBARS), were observed 1 month after (p<0.05). 6-Months later, there was a reduction in TAS, GSH, SOD and GPx, and a increase in TBARS (p<0.05), with a normalization of CAT levels, indicating a persistent alteration of the antioxidant system and the maintenance of oxidative stress. At 12-months, a considerable decrease was observed in TBARS. Additionally, while the level of GPx decreased (p<0.05) further, SOD and GSH levels and TAS were normalizing, indicating a partial regeneration of the antioxidant defence system. These results indicate the possible contribution of oxidative stress to the onset and pathophysiology of schizophrenia, suggesting the involvement of an adaptive response in the antioxidant defence system in the course and outcome in first-episode schizophrenia patients.

Differential effects of linoleic and alpha-linolenic fatty acids on spatial and temporal mitochondrial distribution and activity in bovine oocytes

Using specific stains and confocal microscope imaging, the patterns of mitochondrial distribution, mitochondrial inner membrane potential and reactive oxygen species (ROS) levels during bovine oocyte maturation were determined in the presence or absence of physiological concentrations of linoleic acid (LA; 100µM) or α-linolenic acid (ALA; 50µM). Mitochondrial distribution in control oocytes at 0h was mainly peripheral and changed to a diffused pattern after 1h of culture; this was maintained up to 24h. Mitochondrial clusters were observed during the early hours of maturation (1-4h); the majority of these were arranged in perinuclear fashion. LA supplementation resulted in: (1) delayed redistribution of the mitochondria from a peripheral to a diffuse pattern and a decreased percentages of oocytes showing perinuclear mitochondrial clusters, (2) decreased mitochondrial inner membrane potential at 1 and 24h compared with the control and (3) higher ROS levels, associated with a lower nuclear maturation rate. In contrast, ALA supplementation had no effect on mitochondrial distribution and activity and decreased ROS levels compared with the control; this was associated with an increased nuclear maturation rate. In conclusion, LA induced alterations in mitochondrial distribution and activity as well as increasing ROS levels, which mediate, at least in part, the inhibitory effect on oocyte maturation.

Effects of omega-3 dietary supplement in prevention of positive, negative and cognitive symptoms: a study in adolescent rats with ketamine-induced model of schizophrenia

Omega-3 has shown efficacy to prevent schizophrenia conversion in ultra-high risk population. We evaluated the efficacy of omega-3 in preventing ketamine-induced effects in an animal model of schizophrenia and its effect on brain-derived neurotrophic factor (BDNF). Omega-3 or vehicle was administered in Wistar male rats, both groups at the 30th day of life for 15days. Each group was split in two to receive along the following 7days ketamine or saline. Locomotor and exploratory activities, memory test and social interaction between pairs were evaluated at the 52nd day of life. Prefrontal-cortex, hippocampus and striatum tissues were extracted right after behavioral tasks for mRNA BDNF expression analysis. Bloods for serum BDNF were withdrawn 24h after the end of behavioral tasks. Locomotive was increased in ketamine-treated group compared to control, omega-3 and ketamine plus omega-3 groups. Ketamine group had fewer contacts and interaction compared to other groups. Working memory and short and long-term memories were significantly impaired in ketamine group compared to others. Serum BDNF levels were significantly higher in ketamine plus omega-3 group. There was no difference between groups in prefrontal-cortex, hippocampus and striatum for mRNA BDNF expression. Administration of omega-3 in adolescent rats prevents positive, negative and cognitive symptoms in a ketamine animal model of schizophrenia. Whether these findings are consequence of BDNF increase it is unclear. However, this study gives compelling evidence for larger clinical trials to confirm the use of omega-3 to prevent schizophrenia and for studies to reinforce the beneficial role of omega-3 in brain protection.

The relationship between serum uric acid concentration and metabolic syndrome in patients with schizophrenia or schizoaffective disorder

Higher prevalence rates of metabolic syndrome (MetS) in patients with schizophrenia are getting more and more attention. Uric acid (UA) has been frequently reported to be associated with MetS in the general population. Sex difference in this relationship is inconsistent. As a selective antioxidant, UA has also been found to be reduced in patients with schizophrenia, and this effect may be prominent in men. With the inconsistent presentations, higher rate of MetS but possible lower UA concentrations, the aim of this study was to investigate the relationship by sexes between serum UA concentrations and prevalence of MetS in patients with schizophrenia or schizoaffective disorder. A total of 637 patients, 342 male and 295 female, were enrolled from 36 psychiatric rehabilitation institutions. Cross-sectional anthropometrical data, biochemical analysis, and serum UA were measured. Serum UA concentrations were divided into quartiles by sexes. Modified National Cholesterol Education Program Adult Treatment Panel III criteria for Asians were used as diagnosis of MetS. After adjustment, higher UA concentrations are associated with hypertriglyceridemia, low high-density lipoprotein cholesterol level, and high blood pressure in men and with hypertriglyceridemia in women. Significantly higher odds ratios for MetS in the UA third (4.02; 95% confidence interval, 1.33-12.1) and fourth quartiles (9.28; 95% confidence interval, 2.90-29.8) compared with the lowest quartile were found in men but not in women after adjustment. These results suggest that lower UA concentrations in male patients with schizophrenia or schizoaffective disorder are associated with lower risk of MetS.

The reduction of superoxide dismutase activity is associated with the severity of neurological soft signs in patients with schizophrenia

This study aimed to explore the relationship between antioxidant enzyme activities and neurological soft signs (NSS) in a sample of patients with schizophrenia. Sixty clinically stable patients with schizophrenia treated mostly by first-generation antipsychotics and 30 matched healthy controls were recruited. NSS were assessed in two groups by a standardized neurological examination (Krebs et al., 2000). The red blood cell (RBC) antioxidant activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were measured by spectrophotometry. RBC activities of all enzymes studied: SOD, GSH-Px and CAT, were significantly lower in the patients compared to control group. All NSS scores were significantly higher in the patients compared to healthy controls' scores. In the patients, a negative correlation was found between RBC SOD activity and NSS total score and motor coordination and motor integration sub-scores. The association between low SOD activity as a marker of oxidative stress and NSS in schizophrenic patients suggests a common pathological process of these abnormalities.

Decreased glutathione levels predict loss of brain volume in children and adolescents with first-episode psychosis in a two-year longitudinal study

Progressive loss of cortical gray matter (GM), as measured by magnetic resonance imaging, has been described early in the course of first-episode psychosis. This study aims to assess the relationship between oxidative balance and progression of cortical GM changes in a multicenter sample of first-episode early-onset psychosis (EOP) patients from baseline to two-year follow-up. A total of 48 patients (13 females, mean age 15.9±1.5 years) and 56 age- and gender-matched healthy controls (19 females, 15.3±1.5 years) were assessed. Magnetic resonance imaging (MRI) scans performed both at the time of the first psychotic episode and 2 years later were used for volumetric measurements of left and right gray matter regions (frontal, parietal, and temporal lobes) and total sulcal cerebrospinal fluid (CSF). Total glutathione (GSH) blood levels were determined at baseline. In patients, after controlling for possible confounding variables, lower baseline GSH levels were significantly associated with greater volume decrease in left frontal (B=0.034, 95% confidence interval (CI): 0.011 to 0.056, r=0.620, p=0.006), parietal (B=0.039, 95% CI: 0.020 to 0.059, r=0.739, p=0.001), temporal (B=0.026, 95% CI: 0.016 to 0.036, r=0.779, p<0.001), and total (B=0.022, 95% CI: 0.014 to 0.031, r=0.803, p<0.001) gray matter, and with greater increase in total CSF (B=-0.560, 95% CI: -0.270 to -0.850, r=-0.722, p=0.001). Controls did not show significant associations between brain volume changes and GSH levels. GSH deficit during the first psychotic episode was related to greater loss of cortical GM two years later in patients with first-episode EOP, suggesting that oxidative damage may contribute to the progressive loss of cortical GM found in patients with first-episode psychosis.

Effects of dietary fish oil on the depletion of carcinogenic PAH-DNA adduct levels in the liver of B6C3F1 mouse

Many carcinogenic polycyclic aromatic hydrocarbons (PAHs) and their metabolites can bind covalently to DNA. Carcinogen-DNA adducts may lead to mutations in critical genes, eventually leading to cancer. In this study we report that fish oil (FO) blocks the formation of DNA adducts by detoxification of PAHs. B6C3F1 male mice were fed a FO or corn oil (CO) diet for 30 days. The animals were then treated with seven carcinogenic PAHs including benzo(a)pyrene (BaP) with one of two doses via a single intraperitoneal injection. Animals were terminated at 1, 3, or 7 d after treatment. The levels of DNA adducts were analyzed by the ³²P-postlabeling assay. Our results showed that the levels of total hepatic DNA adducts were significantly decreased in FO groups compared to CO groups with an exception of low PAH dose at 3 d (P = 0.067). Total adduct levels in the high dose PAH groups were 41.36±6.48 (Mean±SEM) and 78.72±8.03 in 10⁹ nucleotides (P = 0.011), respectively, for the FO and CO groups at 7 d. Animals treated with the low dose (2.5 fold lower) PAHs displayed similar trends. Total adduct levels were 12.21±2.33 in the FO group and 24.07±1.99 in the CO group, P = 0.008. BPDE-dG adduct values at 7 d after treatment of high dose PAHs were 32.34±1.94 (CO group) and 21.82±3.37 (FO group) in 10⁹ nucleotides with P value being 0.035. Low dose groups showed similar trends for BPDE-dG adduct in the two diet groups. FO significantly enhanced gene expression of Cyp1a1 in both the high and low dose PAH groups. Gstt1 at low dose of PAHs showed high levels in FO compared to CO groups with P values being 0.014. Histological observations indicated that FO played a hepatoprotective role during the early stages. Our results suggest that FO has a potential to be developed as a cancer chemopreventive agent.

Antioxidants, redox signaling, and pathophysiology in schizophrenia: an integrative view

Schizophrenia (SZ) is a brain disorder that has been intensively studied for over a century; yet, its etiology and multifactorial pathophysiology remain a puzzle. However, significant advances have been made in identifying numerous abnormalities in key biochemical systems. One among these is the antioxidant defense system (AODS) and redox signaling. This review summarizes the findings to date in human studies. The evidence can be broadly clustered into three major themes: perturbations in AODS, relationships between AODS alterations and other systems (i.e., membrane structure, immune function, and neurotransmission), and clinical implications. These domains of AODS have been examined in samples from both the central nervous system and peripheral tissues. Findings in patients with SZ include decreased nonenzymatic antioxidants, increased lipid peroxides and nitric oxides, and homeostatic imbalance of purine catabolism. Reductions of plasma antioxidant capacity are seen in patients with chronic illness as well as early in the course of SZ. Notably, these data indicate that many AODS alterations are independent of treatment effects. Moreover, there is burgeoning evidence indicating a link among oxidative stress, membrane defects, immune dysfunction, and multineurotransmitter pathologies in SZ. Finally, the body of evidence reviewed herein provides a theoretical rationale for the development of novel treatment approaches.

Antioxidant therapeutics for schizophrenia

Pharmaceutical treatment for millions worldwide who have schizophrenia is limited to a handful of antipsychotics. Despite the proven efficacy of these drugs, the overall outcome for schizophrenia remains suboptimal. Thus, alternative treatment options are urgently needed. One possible approach may be antioxidant therapy. The extant evidence for the role of oxidative stress in the pathophysiology of schizophrenia offers a hypothesis-derived therapeutic approach in the form of antioxidants. Vitamins C and E, for example, are suitable for human clinical trials because they are readily available, inexpensive, and relatively safe. Research into the therapeutic use of antioxidants in schizophrenia can be grouped into two main clusters: for psychopathology and for side effects. Of these studies, some have been carefully conducted, but majority are open label. Use of antioxidants for treatment-related side effects has been more extensively investigated. The totality of the evidence to date suggests that specific antioxidants, such as N-acetyl cysteine, may offer tangible benefits for the clinical syndrome of schizophrenia, and vitamin E may offer salutary effects on glycemic effects of antipsychotics. However, a great deal of fundamental clinical research remains to be done before antioxidants can be routinely used therapeutically for schizophrenia and treatment-related complications.

Neuroprotection of paliperidone on SH-SY5Y cells against β-amyloid peptide(25-35), N-methyl-4-phenylpyridinium ion, and hydrogen peroxide-induced cell death

RATIONALE

Antipsychotic drugs (APDs) were widely used in treating schizophrenia. Some APDs were reported to have neuroprotective effects against neurotoxicants in the cell level.

OBJECTIVES

Thus, one typical APD (haloperidol) and three atypical APDs (paliperidone, olanzapine, and risperidone) were tested whether they provide neuroprotection against stressor-induced cell death of SH-SY5Y.

METHODS

Hydrogen peroxide, N-methyl-4-phenylpyridinium ion, and β-amyloid peptide were used to treat cells with or without preconditioning by APDs; cell survival and indicators of oxidative stress were measured, respectively.

RESULTS

Paliperidone has the lowest baseline cytotoxicity compared with other APDs at 24 h; in addition, the paliperidone group showed a better survival than the other APD groups (P < 0.05). In stressor challenging, with a fixed concentration of stressors, olanzapine provided the best neuroprotection at 100 μM against Aβ(25-35) and MPP(+) (P < 0.05). In contrast, paliperidone works finely at low concentrations (10 and 50 μM) against Aβ(25-35) and MPP(+) and solely protected SH-SY5Y from hydrogen peroxide. At 100 μM, paliperidone completely diminished cell reduction induced by different stressors, regardless of their dosages. Paliperidone was demonstrated with a higher oxidative stress-scavenging properties than other APDs in several aspects, such as generated bulk glutathione, low HNE, and protein carbonyl productions. Contradictorily, olanzapine, at 24 h, also enhanced HNE and protein carbonyl productions, which may underlie its induced cytotoxicity.

CONCLUSIONS

Different APDs exhibit variations against different stressors. Paliperidone might be useful not only in alleviating oxidative stress induced by Aβ(25-35) and MPP(+) but also in providing neuroprotection against hydrogen peroxide.

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.

Oxidative stress in schizophrenia

Increasing evidence indicates that oxidative damage exists in schizophrenia. Available literature about possible mechanisms of oxidative stress induction was reviewed. Furthermore, possibilities of measuring biomarkers of schizophrenia outside the central nervous system compartment, their specificity for different types of schizophrenia and potential therapeutic strategies to prevent oxidative injuries in schizophrenia were discussed. Data were extracted from published literature found in Medline, Embase, Biosis, Cochrane and Web of Science, together with hand search of references. Search terms were: schizophrenia, oxidative stress, antipsychotics, antioxidants and fatty acids. Finding a sensitive, specific and non invasive biomarker of schizophrenia, which could be measured in peripheral tissue, still stays an important task. Antioxidant enzymes, markers of lipid peroxidation, oxidatively modified proteins and DNA are most commonly used. As it considers the supplemental therapy, according to our meta-analysis vitamin E could potentially improve tardive dyskinesia, while for the effect of therapy with polyunsaturated fatty acids there is no clear evidence. Oxidative stress is a part of the pathology in schizophrenia and appears as a promising field to develop new therapeutic strategies. There is a need for well designed, placebo controlled trials with supplementation therapy in schizophrenia.

Reduced plasma total antioxidant status in first-episode drug-naive patients with schizophrenia

Excessive free radical production leading to oxidative stress may be involved in the pathophysiology of schizophrenia. Determination of total antioxidant status (TAS) provides an index of the sum of activities of all antioxidants. However, there have been few systematic studies to examine the relationship between TAS levels and psychopathology in first-episode and drug-naive patients with schizophrenia. TAS levels were determined in the plasma of 60 never-medicated first-episode patients with schizophrenia and 68 healthy control subjects. The schizophrenia symptomatology and the depressive symptoms were assessed by the positive and negative syndrome scale (PANSS) and the Hamilton rating scale for depression (HAMD). The results showed that TAS levels were significantly lower in first-episode patients with schizophrenia than in healthy control subjects (159.8 ± 45.8 U/ml vs 211.4 ± 46.8 U/ml, F=39.5, df=1, 126, p < 0.001). A trend toward significant inverse correlation between TAS levels and PANSS negative subscore was observed (r = 0.25, df=60, p = 0.06). Our results suggest that oxidative stress occurs in an early course of schizophrenia and may have an important role in pathogenesis and perhaps, negative symptomatology of schizophrenia.