Oxidative mechanisms in schizophrenia and their relationship with illness subtype and symptom profile

Schizophrenia and Glutathione: A Challenging Story

Schizophrenia (SZ) is a devastating mental illness with a complex and heterogeneous clinical state. Several conditions like symptoms, stage and severity of the disease are only some of the variables that have to be considered to define the disorder and its phenotypes. SZ pathophysiology is still unclear, and the diagnosis is currently relegated to the analysis of clinical symptoms; therefore, the search for biomarkers with diagnostic relevance is a major challenge in the field, especially in the era of personalized medicine. Though the mechanisms implicated in SZ are not fully understood, some processes are beginning to be elucidated. Oxidative stress, and in particular glutathione (GSH) dysregulation, has been demonstrated to play a crucial role in SZ pathophysiology. In fact, glutathione is a leading actor of oxidative-stress-mediated damage in SZ and appears to reflect the heterogeneity of the disease. The literature reports differing results regarding the levels of glutathione in SZ patients. However, each GSH state may be a sign of specific symptoms or groups of symptoms, candidating glutathione as a biomarker useful for discriminating SZ phenotypes. Here, we summarize the literature about the levels of glutathione in SZ and analyze the role of this molecule and its potential use as a biomarker.

Oxidative Stress Biomarkers among Schizophrenia Inpatients

Background. Finding the associations between schizophrenia symptoms and the biomarkers of inflammation, oxidative stress and the kynurenine pathway may lead to the individualization of treatment and increase its effectiveness. Methods. The study group included 82 schizophrenia inpatients. The Positive and Negative Symptoms Scale (PANSS), the Brief Assessment of Cognition in Schizophrenia (BACS) and the Calgary Depression in Schizophrenia Scale were used for symptom evaluation. Biochemical analyses included oxidative stress parameters and brain-derived neurotrophic factor (BDNF). Results. Linear models revealed the following: (1) malondiadehyde (MDA), N-formylkynurenine (N-formKYN), advanced oxidation protein products (AOPP), advanced glycation end-products of proteins (AGE) and total oxidative status (TOS) levels are related to the PANSS-total score; (2) MDA, reduced glutathione (GSH) and BDNF levels are related to the PANSS-negative score; (3) TOS and kynurenine (KYN) levels are related to the PANSS-positive score; (4) levels of total antioxidant status (TAS) and AOPP along with the CDSS score are related to the BACS-total score; (5) TAS and N-formKYN levels are related to the BACS-working memory score. Conclusions. Oxidative stress biomarkers may be associated with the severity of schizophrenia symptoms in positive, negative and cognitive dimensions. The identification of biochemical markers associated with the specific symptom clusters may increase the understanding of biochemical profiles in schizophrenia patients.

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.

Advanced glycation end-products and advanced oxidation protein products in schizophrenia

Schizophrenia pathophysiology is still not well understood. Genetic factors involving biochemical systems are key players and oxidative stress takes part to the development and worsening of SZ. Oxidative stress led to the permanent production of oxidation products such as advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs). These proteins interact with their receptor amplifying ROS production and pro-inflammatory cytokines sustaining a permanent loop. We tested plasma levels of AGEs and AOPPs in 30 SZ patients. Their levels were statistically higher than controls confirming their involvement in mental disorders. Antioxidant nutraceuticals and a healthy lifestyle could diminish oxidative stress and ameliorate SZ symptoms.

Effects of antipsychotics on antioxidant defence system in patients with schizophrenia: A meta-analysis

Theory of oxidative stress is suggested in the pathophysiology of schizophrenia. To determine the cause of impaired antioxidant defense system in schizophrenia, a meta-analysis was performed by selecting studies published from 1964 to 2021 from Pubmed and Scopus databases. Data were analysed using Comprehensive Meta-Analysis version 2 and calculated effect sizes were compared between unmedicated and medicated patients with schizophrenia and healthy controls. Heterogeneity, publication bias assessments and subgroup analyses of drug-free and drug-naïve patients, and patients treated with atypical and typical antipsychotics were conducted. Subgroup analysis of confounding factors including age, gender, illness duration and patient status was also conducted. We found that glutathione peroxidase (GPx) was significantly decreased in all patients. Significantly lower catalase (CAT), glutathione (GSH) and albumin (ALB) were found in unmedicated patients only. Both groups showed significantly weakened non-enzymatic antioxidant capacity. Subgroup analyses indicated that weakened non-enzymatic antioxidant capacity may be associated with schizophrenia. Antioxidant status was more impaired in drug-free patients compared with other subgroups. This indicated that antipsychotics may improve antioxidant defense system. Although effect sizes were smaller, future studies may focus on the effect of antipsychotic discontinuation. In overall, schizophrenia was associated with impaired antioxidant defense system especially the non-enzymatic antioxidant system.

Blood-based oxidation markers in medicated and unmedicated schizophrenia patients: A meta-analysis

Increased reactive species due to the effect of antipsychotics on oxidative stress may be involved in the development of schizophrenia. However, antipsychotics may have different direct antioxidant effects due to their chemical structures. The present meta-analysis aimed to investigate whether the cause increased oxidant status in schizophrenia patients is due to the illness or induction by antipsychotics. Studies published from 1964 to 2021 were selected from Pubmed and Scopus databases. Data were analysed using Comprehensive Meta-Analysis version 2. Effect sizes were calculated and compared between unmedicated and medicated patients and healthy controls. Heterogeneity and publication bias were assessed. Subgroup analyses were conducted on drug-free and drug-naïve patients, and patients treated with atypical and typical antipsychotics. We found that medicated patients had significantly higher malondialdehyde (MDA), thiobarbituric acid reactive substances (TBARS) and total oxidant status (TOS). Meanwhile, significantly increased plasma/serum MDA and nitric oxide (NO) were observed in unmedicated patients only. Higher lipid peroxidation in the drug-naïve group may be associated schizophrenia. However, both atypical and typical antipsychotics may worsen lipid peroxidation. Antipsychotic discontinuation in the drug-free group led to significantly increased plasma/serum NO, with larger effect size than the atypical antipsychotic group. In conclusion, medicated schizophrenia patients were more suffered from increased oxidative stress. Therefore, future study may focus on the mechanism of action of specific antipsychotic on oxidative stress.

Pro/Antioxidant State as a Potential Biomarker of Schizophrenia

To allow better diagnosis and management of psychiatric illnesses, the use of easily accessible biomarkers are proposed. Therefore, recognition of some diseases by a set of related pathogenesis biomarkers is a promising approach. The study aims to assess the usefulness of examining oxidative stress (OS) in schizophrenia as a potential biomarker of illness using the commonly used data mining decision tree method. The study group was comprised of 147 participants: 98 patients with schizophrenia (SZ group), and the control group (n = 49; HC). The patients with schizophrenia were divided into two groups: first-episode schizophrenia (n = 49; FS) and chronic schizophrenia (n = 49; CS). The assessment included the following biomarkers in sera of patients: catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase-1 (SOD-1), glutathione reductase (GR), reduced glutathione (GSH), total antioxidant capacity (TAC), ferric reducing ability of plasma (FRAP), advanced glycation end products (AGEs), advanced oxidation protein products (AOPP), dityrosine (DITYR), kynurenine (KYN), N-formylkynurenine (NFK), tryptophan (TRY), total oxidant status (TOS), nitric oxide (NO) and total protein. Maximum accuracy (89.36%) for distinguishing SZ from HC was attained with TOS and GPx (cut-off points: 392.70 and 15.33). For differentiating between FS and CS, the most promising were KYN, AOPP, TAC and NO (100%; cut-off points: 721.20, 0.55, 64.76 and 2.59). To distinguish FS from HC, maximum accuracy was found for GSH and TOS (100%; cut-off points: 859.96 and 0.31), and in order to distinguish CS from HC, the most promising were GSH and TOS (100%; cut-off points: 0.26 and 343.28). Using redox biomarkers would be the most promising approach for discriminating patients with schizophrenia from healthy individuals and, in the future, could be used as an add-on marker to diagnose and/or respond to treatment.

Oxidative Stress in the Early Stage of Psychosis

BACKGROUND

In the past few decades, increasing evidence in the literature has appeared describing the role of the antioxidant defense system and redox signaling in the multifactorial pathophysiology of psychosis. It is of interest to clinicians and researchers alike that abnormalities of the antioxidant defense system are associated with alterations of cellular membranes, immune functions and neurotransmission, all of which have some clinical implications.

METHODS

This narrative review summarizes the evidence regarding oxidative stress in the early stages of psychosis. We included 136 peer-reviewed articles published from 2007 to 2020 on PubMed EMBASE, The Cochrane Library and Google Scholar.

RESULTS

Patients affected by psychotic disorders show a decreased level of non-enzymatic antioxidants, an increased level of lipid peroxides, nitric oxides, and a homeostatic imbalance of purine catabolism. In particular, a significantly reduced antioxidant defense has been described in the early onset first episode of psychosis, including reduced levels of glutathione. Also, it has been shown that a decreased basal low -antioxidant capacity correlates with cognitive deficits and negative symptoms, mostly related to glutamate-receptor hypofunction. In addition, atypical antipsychotic drugs seem to show significant antioxidant activity. These factors are critical in order to treat cases of first-onset psychosis effectively.

CONCLUSION

This systematic review indicates the importance that must be given to anti-oxidant defense systems.

The Augmentation Effect of N-Acetyl Cysteine Antioxidant on Superoxide Dismutase Levels in Schizophrenic Patients Treated with Risperidone

Background: Schizophrenia affects approximately 1% of the population and in Indonesia the prevalence is about 400.000 people or as many as 1.7 per 10000 individuals of the population. Schizophrenia is characterized by positive symptoms, negative symptoms and also cognitive, aggressive, and affective symptoms, where negative symptoms reflect loss of function. One important factor that plays a role in the pathophysiology of schizophrenia is the excessive production of free radical substances and the failure of the anti-oxidant defense process. The aim of this study is to see how levels of superoxide dismutase change after N-acetylcystein augmentation in schizophrenic patients treated with risperidone. This study is a pre-post experimental test design, where schizophrenic patients meet inclusion and exclusion criteria. At baseline, and after 8 weeks of N-acetyl cysteine administration, patients were assessed at each of the time points using PANSS, and SOD was measured in blood at both time points.       The average negative PANSS score in the Risperidone + NAC baseline group was 29.93 (±1.83); in the Risperidone group was 29.83 (±1.19)  (p = 0.87). The average negative PANSS score at the end of week 8 was statistically significantly different (p = 0.001) in the Risperidone + NAC group (17.40 ±1.84) and in the Riseridone group (21.00±0.74). The average baseline SOD levels in the Risperidone + NAC group were 63.57 (±22.44), and in the Risperidone group was 85.79 (±101.05). SOD levels at week 8 in the Risperidone + NAC group were 71.72 (±31.20) and in the Risperidone group 128.27 (±117.67). ∆ SOD in the Risperidone + NAC group was 8.15 (19.54) and ∆ SOD in the Risperidone group was 42.48± (54.30).  p value of 0.028Research data shows that NAC augmentation can improve the negative symptoms of schizophrenia through reducing SOD levels in the blood.

Efficacof Cinnamon Extract (Cinnamomum burmannii) as Supplementation in Lir-psychotic-induced Rats through Oxidative Stress Regulation in Neuronal Cells

BACKGROUND: Cinnamon is a plant that is often found in Indonesia and is rich in secondary metabolites such as flavonoids, phenols, tannins, and alkaloids. Flavonoids and phenols are very potential as natural antioxidants to suppress various oxidant activities, including oxidant activity that occurs in the hippocampus, which is the underlying psychotic disorder. AIM: This study was aimed to explore the potential of cinnamon extract (CE) on psychotic symptoms. METHODS: Cinnamon simplicia was obtained from the Research and Testing Center for Traditional Medicine, Tawangmangu, Central Java, Indonesia. The extraction of cinnamon was carried out using the maceration method. The animals were subjected to lir-psychotic induction by intraperitoneal injection with ketamine (30 mg/kg BW) for 5 days. The rats were grouped into six groups; each group contained five animals; normal control group, a lir-psychotic group without treatment, lir-psychotic group with haloperidol, lir-psychotic with CE (25 mg/kg BW, 50 mg/kg BW, and 100 mg/kg BW). Oxidative stress in experimental animals was measured by evaluating malondialdehyde (MDA) expression in the brain tissue using immunohistochemical tests. RESULTS: There were differences in clinical symptoms of psychotic disorder in the animal model between before intervention with CE supplementation and after the intervention. The higher the CE dose administered, the better the improvement in psychotic symptoms seen in the psychotic-induced rats. CE supplementation could reduce MDA expression in the hippocampus. This suggests that there was an optimal significance of cinnamon supplementation in reducing oxidative stress from the hippocampus. CONCLUSION: CE was effective in improving psychotic symptoms in lir-psychotic rats through regulation of oxidative stress in neuronal cells.

Predictive value of oxidative stress biomarkers in drug‑free patients with schizophrenia and schizo-affective disorder

Several studies have suggested that oxidative stress may represent one of the primary etiological mechanisms of schizophrenia (SZ) and schizoaffective disorder (SAD) which can be targeted by therapeutic intervention. The present study was conducted over a period of 24 months, between June 2016 and June 2018. All enrolled subjects were Tunisian, forty five drug‑free male patients with SZ (mean age: 37.6 years), twenty one drug‑free male patients with SAD (mean age: 28.8 years) and hundred and one age and gender matched controls (mean age: 34.2 years) were enrolled in the study. Plasma reduced glutathione (GSH) and Total thiols levels were significantly decreased in patients compared to controls (respectively p<0.001; p=0.050). In addition, malondialdehyde (MDA), advanced oxidation protein products (AOPP) and protein carbonyls (PC) concentrations and glutathione peroxidase (GSH-Px) activity were significantly increased in patients compared to controls (p<0.001; p<0.001; p<0.001 and p=0.003 respectively). The binary logistic regression analysis revealed that MDA, AOPP, PC and GSH-Px could be considered as independent risk factors for SZ and SAD. When using ROC analysis, a remarkable increase in the area under the curve (AUC) with higher sensitivity (Se) and specificity (Sp) for MDA, AOPP, PC and GSH-Px combined markers was observed. The present study indicated that the identification of the predictive value of this four-selected biomarkers related to oxidative stress in drug free patients should lead to a better identification of the etiological mechanism of SZ or SAD.

Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

While neurotransmitter dysfunction represents a key component in mental illnesses, there is now a wide agreement for a central pathophysiological hub that includes hormones, neuroinflammation, redox mechanisms as well as oxidative stress. With respect to oxidation-reduction (redox) mechanisms, preclinical and clinical evidence suggests that an imbalance in the pro/anti-oxidative homeostasis toward the increased production of substances with oxidizing potential may contribute to the etiology and manifestation of different psychiatric disorders. The substantial and continous demand for energy renders the brain highly susceptible to disturbances in its energy supply, especially following exposure to stressful events, which may lead to overproduction of reactive oxygen and nitrogen species under conditions of perturbed antioxidant defenses. This will eventually induce different molecular alterations, including extensive protein and lipid peroxidation, increased blood-brain barrier permeability and neuroinflammation, which may contribute to the changes in brain function and morphology observed in mental illnesses. This view may also reconcile different key concepts for psychiatric disorders, such as the neurodevelopmental origin of these diseases, as well as the vulnerability of selective cellular populations that are critical for specific functional abnormalities. The possibility to pharmacologically modulate the redox system is receiving increasing interest as a novel therapeutic strategy to counteract the detrimental effects of the unbalance in brain oxidative mechanisms. This review will describe the main mechanisms and mediators of the redox system and will examine the alterations of oxidative stress found in animal models of psychiatric disorders as well as in patients suffering from mental illnesses, such as schizophrenia and major depressive disorder. In addition, it will discuss studies that examined the effects of psychotropic drugs, including antipsychotics and antidepressants, on the oxidative balance as well as studies that investigated the effectiveness of a direct modulation of oxidative mechanisms in counteracting the behavioral and functional alterations associated with psychiatric disorders, which supports the promising role of the redox system as a novel therapeutic target for the improved treatment of brain disorders.

l-Arginine metabolism before and after 10 weeks of antipsychotic treatment in first-episode psychotic patients

Agmatine is an endogenous NMDA (N-methyl-d-aspartate) antagonist which is synthesized from l-Arginine and described as a novel neurotransmitter. Agmatine is considered to play an important role for the development of schizophrenia. The aim of the present study is to explore the role of agmatine and l-arginine metabolism in medication-naive first-episode psychosis (FEP). We conducted a case control study in medication-naive patients with FEP (n = 40). The healthy volunteers with no family history of schizophrenia (n = 35) matched for age, gender and education level were selected as a control group. The patients were recruited to the study and followed up for 10 weeks. The plasma l-arginine, l-citrulline, l-ornithine and agmatine levels were measured using modified liquid chromatography/mass spectrometry. The plasma levels of l-arginine, l-citrulline and agmatine (p < 0.0001), but not l-ornithine and agmatinase (p > 0.05), were significantly increased during baseline analysis. After 10 weeks of treatment, plasma l-arginine and l-citrulline levels were still significantly increased (p < 0.05) while l-ornithine and agmatinase levels remained unchanged (p > 0.05). Conversely, plasma agmatine levels were significantly decreased after the treatment (p < 0.0001). Positive and negative predictive values of agmatine used for evaluating the diagnostic accuracy were 95.1% and 97.1%, respectively (p < 000.1). This is the first study of arginine metabolism and agmatine in medication-naive first-episode patients and provides evidence of increased levels of an endogenous NMDA antagonist which decreases following antipsychotic treatment.

Day/Night and Summer/Winter Changes in Serum Total Antioxidant Capacity

BACKGROUND

Seasonal and circadian changes are two factors described to affect blood levels of some biological molecules. The Total Antioxidant Capacity (TAC) is one global measure of the antioxidant capacity of a system. There is no agreement about the existence of day/night changes in TAC levels as well as there is no information about seasonal changes in TAC levels.

OBJECTIVE

The aims of this research are studying if there are summer/winter changes in TAC concentrations or if TAC concentrations have day/night changes.

METHOD

Ninety-eight healthy subjects took part in the summer study of whom 64 participated in the winter one. Blood was sampled at 09:00, 12:00 and 00:00 h. TAC was measured by the ABTS radical cation technique. Results are expressed in mmol/L of trolox equivalents.

RESULTS

The subjects had significantly higher TAC levels in summer than winter at the three-time point studied. Summer 09:00 TAC concentration was significantly higher than the 12:00 and 00:00 h concentrations (1.34±0.26 vs 0.83±0.19, 0.75±0.18). Summer TAC 12:00 h concentrations were significantly higher than the 00:00 h concentrations (0.83±0.19 vs. 0.75±0.18). Winter 09:00 TAC concentrations were significantly higher than the 12:00 and 00:00 h concentrations (1.24±0.16 vs. 0.73±0.10, 0.67±0.13). There were no significant differences between the 12:00 and 00:00 h TAC concentrations.

CONCLUSION

Strong methodological biases may be made if the seasonal and circadian changes in serum TAC concentration are not taken into account when researching in this area.

Morin Attenuates Neurochemical Changes and Increased Oxidative/Nitrergic Stress in Brains of Mice Exposed to Ketamine: Prevention and Reversal of Schizophrenia-Like Symptoms

Previous studies have revealed that morin (MOR), a neuroactive bioflavonoid, with proven psychotropic and neuroprotective properties reduced schizophrenic-like behaviors in mice. This study further evaluated the ability of MOR to prevent and reverse ketamine-induced schizophrenic-like behaviors and the underlying neurochemical changes and increased oxidative/nitrergic stress in mice. In the preventive protocol, mice received intraperitoneal injection of MOR (100 mg/kg), reference antipsychotic drugs [haloperidol (1 mg/kg), risperidone (0.5 mg/kg)], or saline daily for 14 consecutive days prior to i.p. injection of ketamine (KET) (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days prior to MOR, haloperidol, risperidone, or saline treatments. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction test) and cognitive (Y-maze test) symptoms were evaluated. Thereafter, the brain levels of dopamine, glutamate, 5-hydroxytryptamine and acetyl-cholinesterase, as well as biomarkers of oxidative/nitrergic stress were measured in the striatum, prefrontal-cortex (PFC) and hippocampus (HC). Morin prevented and reversed KET-induced hyperlocomotion, social and cognitive deficits. Also, MOR or risperidone attenuated altered dopaminergic, glutamatergic, 5-hydroxytryptaminergic and cholinergic neurotransmissions in brain region-dependent manner. The increased malondialdehyde and nitrite levels accompanied by decreased glutathione concentrations in the striatum, PFC and HC in KET-treated mice were significantly attenuated by MOR or risperidone. Taken together, these findings suggest that the anti-schizophrenic-like activity of MOR may be mediated via mechanisms related to attenuation of neurochemical changes and oxidative/nitrergic alterations in mice.

Probable mechanisms involved in the antipsychotic-like activity of morin in mice

Evidence derived from preliminary studies suggests that morin, a neuroactive flavonoid with proven antioxidant and antiinflammatory properties possess antipsychotic-like activity. The present study was designed to evaluate the probable mechanisms involve in the antipsychotic-like activity of morin in ketamine model of schizophrenia. The effects of morin, haloperidol and risperidone on neurobehavioral and anti-schizophrenia-like effects were evaluated in mice (n = 7) following intraperitoneal (i.p.) administration of morin (25-100 mg/kg), haloperidol (1 mg/kg) and risperidone (0.5 mg/kg) alone or in combination with ketamine (20 mg/kg, i.p.) for 10 days. Neurobehavioral and schizophrenia-like activities consisting of open-field (positive symptoms), Y-maze, novel-object recognition (cognitive symptoms), social interaction (negative symptoms) tests were assessed. Also, wood-block catalepsy and rota-rod tests were employed to evaluate extrapyramidal side effects of morin. Thereafter, brain levels of biomarkers of oxidative, nitrergic and acetylcholinesterase alterations as well as histomorphological changes in the striatum and prefrontal-cortex were determined. Administration of morin and risperidone alone but not haloperidol significantly (p > 0.05) prevented ketamine-induced hyperlocomotion, social withdrawal and cognitive impairments relative to controls, and were devoid of extrapyramidal side effects. Morin alone or in combination with ketamine significantly increased glutathione concentration, superoxide dismutase and catalase activities compared with saline- or ketamine-treated mice. Moreover, morin alone or in combination with ketamine also significantly decreased malondialdehyde, nitrite and acetylcholinesterase alterations in mice brains. Furthermore, morin prevented ketamine-induced brain neuronal alterations in the striatum and prefrontal-cortex. Together, our findings suggest that morin may demonstrate antipsychotic-like therapeutic effect via modulation of oxidative/nitrergic, cholinergic actions and neuroprotection.

Thiol Disulfide Homeostasis in Schizophrenic Patients Using Atypical Antipsychotic Drugs

Objective

Schizophrenia is a severe, debilitating mental disorder characterized by behavioral abnormalities. Although several studies have investigated the role of oxidative stress and the effects of antipsychotic drugs on oxidative markers in schizophrenia, adequate information is not available on these issues. The aim of this study is to determine the changes in oxidative status and thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs.

Methods

Thirteen schizophrenic patients using atypical antipsychotic drugs and 30 healthy controls were included this study. The concentrations of total oxidant status (TOS), total antioxidant status (TAS), native thiol, total thiol, and disulfide levels were determined in the study population.

Results

The TAS (p=0.001), total thiol, and native thiol levels (p<0.001) were higher in the patients compared to the controls, whereas the TOS and disulfide levels were lower in the patients than in the controls (p<0.001).

Conclusion

These results may suggest that atypical antipsychotic drugs have a useful therapeutic effect by reducing oxidative stress via the inhibition of the formation of disulfide bonds. The study population number was one of the limitations of this study. Therefore, further studies are needed to establish the association between thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs.

A three-month longitudinal study of changes in day/night serum total antioxidant capacity in paranoid schizophrenia

Free radicals and an oxidant/antioxidant imbalance have been involved in the schizophrenia pathophysiology. The total antioxidant capacity (TAC) is a measure of the antioxidant capacity of a system. Day/night changes are a biological characteristic of hormones such as melatonin or cortisol. There is little information about TAC day/night changes in schizophrenia patients. The aim of this research is to study if there are day/night changes in serum TAC levels of schizophrenia patients. Thirty-two DSM-IV schizophrenia paranoid patients were studied. Blood was sampled at 12:00 and 00:00 h at admission, discharge and three months after hospital discharge (TMAHD). TAC results are expressed as mmol of Trolox/L. Patients did not have day/night TAC differences at admission (12:00: 0.67±0.12 vs. 00:00: 0.61±0.14, p>0.14) or discharge (12:00: 0.65±0.15 vs. 00:00: 0.65±0.12, p>0.99). At TMHD, patients had significantly higher TAC levels at midday than midnight (12:00: 0.83±0.10 vs. 00:00: 0.74±0.12, p<0.006) as it has been reported in healthy subjects. There were no significant TAC differences at 12.00 and 00:00 between admission and discharge. At TMAHD, patients had significantly higher TAC levels than at admission and discharge, both at 12:00 and 00:00 h. In conclusion, the absence of day/night serum TAC changes when clinically relapsed and the normalization of day/night serum TAC changes at TMHD can be considered as a biological marker of schizophrenia evolution.

GSTM1/GSTT1 double-null genotype increases risk of treatment-resistant schizophrenia: A genetic association study in Brazilian patients

BACKGROUND

The role of oxidative stress in schizophrenia has been demonstrated, particularly in subjects with treatment-resistant schizophrenia (TRS). In such patients, the decreased levels of antioxidants in conjunction with the increased generation of reactive oxygen species in the brain exposes the neurons to a higher risk of damage.

METHODS AND FINDINGS

We evaluated the association of deletion polymorphisms of two genes of the antioxidant Glutathione S-Transferase family, GSTT1 and GSTM1, with susceptibility to TRS. A total of 54 TRS patients (mean age 38.7 years) and 78 healthy control subjects (mean age 39.0 years) were enrolled in this study. The subjects were matched by sex, age, and smoking and alcohol consumption habits. In the case group, the frequencies of GSTT1-null and GSTM1-null genotypes were 24.1 and 51.9%, respectively, whereas for the control group, the frequencies were 12.8 and 46.2%, respectively. Analysis performed with respect to the risk of developing TRS associated with the GSTT1 and GSTM1 deletion polymorphisms, resulted in odds ratio (OR) values of 2.1 and 1.2, respectively. However, the association was not found to be significant (p = 0.1229 and p = 0.5916, respectively). The analysis performed with respect to the combined genotypes of GSTT1 and GSTM1 revealed that the double-null genotype confers a 4.6-fold increased risk of developing TRS (p = 0.0412).

CONCLUSION

The results of the present study indicate that a combination of GST deficiencies may play a role in enhanced susceptibility to TRS, and the present genotype of one of these genes may buffer the deficiency caused by the lack (null genotype) of the other. The results suggest that combined deletion polymorphisms of GSTT1 and GSTM1 can have implications in the prediction of the clinical course of the disease.

Thiol/disulfide homeostasis in untreated schizophrenia patients

BACKROUND

The aim of the study was to investigate dynamic thiol/disulfide (SH/SS) homeostasis in untreated schizophrenia.

METHODS

Blood thiol/disulfide homeostasis status, which reflects native thiol-disulfide exchanges, was investigated in 87 untreated patients (52 males, 35 females), and the obtained results were compared with 86 healthy controls. Blood serum native thiol and total thiol (ToSH) concentrations were measured in a paired test. The half value of the difference between native thiol and ToSH concentrations was calculated as the disulfide bond amount.

RESULTS

SH and ToSH concentrations were found to be significantly lower (p<0.001 for both) in patients with untreated schizophrenia compared with the control group, whereas disulfide levels were significantly higher (p<0.001). Schizophrenia patients had significantly higher SS/ToSH and SS/SH ratios and a significantly lower SH/ToSH ratio compared to those of healthy individuals.

CONCLUSIONS

SH and ToSH amounts were found to be insufficient in untreated schizophrenia patients. Additionally, according to the results of the study, thiol/disulfide homeostasis was also disturbed by a shift to the disulfide bond formation side. This might affect the neurotransmission processes, which are known to be related with many symptoms observed in schizophrenia. The replacement of the thiol gap and the reduction of excess SS amounts might have a positive effect in supporting therapy for schizophrenia patients.

Low levels of serum total antioxidant capacity and presence at admission and absence at discharge of a day/night change as a marker of acute paranoid schizophrenia relapse

BACKGROUND

An oxidant-antioxidant system dysregulation has been described as a schizophrenia pathophysiological base. The total antioxidant capacity (TAC) is one measure of the antioxidant capacity of a system. Day/night concentration changes is a biological characteristic of hormones such as melatonin or cortisol. There is no information about TAC day/night changes in schizophrenia.

AIMS

Studying the existence of a day/night TAC change in schizophrenia.

METHOD

Forty-three DSM-IV paranoid schizophrenia inpatients participated in the study. Thirty healthy subjects matched by age and gender acted as control group. Blood was sampled at 12:00 and 00:00h the day after admission and the day before discharge. Serum TAC was measured by the ABTS radical cation technique and expressed in Trolox mmol/L.

RESULTS

Patients had significantly lower TAC levels at admission and discharge (12:00 and 00:00) than controls. At admission patients had a TAC day/night change, with higher day-time than night-time levels (0.66±0.14 vs 0.60±0.15) as well as healthy subjects (0.83±0.07 vs 0.77±0.11). At discharge patients had a similar TAC level at 12:00 and 00:00 (0.64±0.15 vs 0.63±0.14).

CONCLUSION

Schizophrenic patients present a deficit of the antioxidant system. The initial presence and the later absence of a day/night change deserves future studies.

Evaluation of Oxidative Status in Patients Treated with Electroconvulsive Therapy

Objective

Electroconvulsive therapy (ECT) is used in the treatment of many psychiatric diseases and this therapy may be effective on antioxidant defence system. In this study, we aimed to evaluate the effects of ECT on oxidative stress.

Methods

Fourteen major depression, 11 schizophrenia and 8 bipolar affective disorder patients diagnosed and received ECT treatment, and 37 healthy volunteers enrolled in the study. ECT was applied to all patients. Before ECT, after the first and last ECTs, serum samples were obtained. Serum total antioxidant status (TAS), total oxidant status (TOS), and calculated oxidative stress index (OSI) were measured in patients before and after ECTs.

Results

TOS values before ECT were higher in major depression (p=0.005) and schizophrenia (p=0.001) groups compared to the control group. TAS values were lower in major depression (p=0.0001), schizophrenia (p=0.004), bipolar affective disorder (p=0.004) groups compared to the controls. Also OSI values were higher in major depression (p=0.0001), schizophrenia (p=0.001), bipolar affective disorder (p=0.009) groups compared to healthy group. After the last ECT, TOS values were significantly lower compared to TOS values before ECT in major depression (p=0.004) and schizophrenia patients (p=0.004). TAS values after the first ECT were higher compared to values before ECT in major depression patients (p=0.004). After last ECT, OSI values were significantly lower compared to before ECT in schizophrenia patients (p=0.006).

Conclusion

As a result, it can be said that ECT did not increase oxidative stress. However, further studies with more patients are needed.

Neuroprotective effects of the ethanol stem bark extracts of Terminalia ivorensis in ketamine-induced schizophrenia-like behaviors and oxidative damage in mice

CONTEXT

Schizophrenia is a heterogenous neurological disorder, which has been hypothetically linked to oxidative imbalance and associated behavioral perturbations. Preliminary evidence from animal models predictive of human psychosis suggests that Terminalia ivorensis A. Chev. (Combretaceae) has antipsychotic-like activity in mice.

OBJECTIVE

This study investigates the neuroprotective property of the ethanol stem bark extracts of T. ivorensis (EETI) in reversal treatment of ketamine-induced schizophrenia-like behaviors and oxidative alteration in adult male Swiss albino mice.

MATERIALS AND METHODS

Animals were divided into six treatment groups (n = 5). Animals received distilled water or ketamine (20 mg/kg) once daily intraperitoneally (i.p.) for 14 days, and from the 8th to the 14th day, they were treated with EETI (125, 250 or 500 mg/kg), risperidone (RIS) or vehicle orally once daily. Behaviors related to positive (locomotor activity) and cognitive (Y maze) symptoms of schizophrenia were assessed. Glutathione (GSH) levels, superoxide dismutase (SOD) and catalase (CAT) activities, including malondialdehyde (MDA) concentration were measured in mice whole brains.

RESULT

The LD₅₀ of EETI was 2236.06 mg/kg, p.o. body weight. EETI (125, 250 or 500 mg/kg, p.o.) demonstrated significant (p < 0.05) inhibition of ketamine-induced hyperlocomotion and cognitive dysfunction. The extract decreased MDA concentration (39.0, 62.6 and 67.5%) in a dose-dependent manner. Moreover, EETI significantly (p < 0.05) reversed the depletion of GSH, and increased activities of SOD and CAT in brain tissues.

DISCUSSION AND CONCLUSION

These findings suggest that EETI probably exert its antipsychotic-like activity, via a neuroprotective compensatory mechanism of action, and as such, could be relevant in the management of schizophrenia.

N-acetylcysteine in the treatment of psychiatric disorders: current status and future prospects

INTRODUCTION

N-acetylcysteine (NAC) is widely known for its role as a mucolytic and as an antidote to paracetamol overdose. There is increasing interest in the use of NAC in the treatment of several psychiatric disorders. The rationale for the administration of NAC in psychiatric conditions is based on its role as a precursor to the antioxidant glutathione, and its action as a modulating agent of glutamatergic, dopaminergic, neurotropic and inflammatory pathways. Areas covered: This study reviews the available data regarding the use of NAC in different psychiatric disorders including substance use disorders, autism, obsessive-compulsive spectrum disorders, schizophrenia, depression, bipolar disorder. Promising results were found in trials testing the use of NAC, mainly as an add-on treatment, in cannabis use disorder in young people, depression in bipolar disorder, negative symptoms in schizophrenia, and excoriation (skin-picking) disorder. Despite initial optimism, recent findings regarding NAC efficacy in autism have been disappointing. Expert opinion: These preliminary positive results require further confirmation in larger samples and with longer follow-ups. Given its high tolerability and wide availability, NAC represents an important target to investigate in the field of new adjunctive treatments for psychiatric conditions.

Elevated plasma F2-isoprostane levels in schizophrenia

BACKGROUND

Schizophrenia is one of the most disabling psychiatric disorders with increased morbidity and mortality. Both schizophrenia and oxidative stress have been associated with accelerated aging. Previous studies found increased oxidative stress in individuals with schizophrenia, though only one study measured F2-isoprostanes and did so in urine. To our knowledge, the present study is the first to assess plasma F2-isoprostane levels, the putative gold standard measure of systemic oxidative stress in vivo, in schizophrenia.

METHODS

We compared plasma F2-isoprostane levels in 134 stable outpatients with schizophrenia and 120 age- and gender-matched healthy comparison (HC) subjects. Sociodemographic and clinical data were collected in both groups.

RESULTS

Plasma F2-isoprostane levels were significantly higher in the schizophrenia group than in the HC group. Women had higher F2-isoprostane levels compared to men, and those with higher body mass index (BMI) had higher levels, within each group. F2-isoprostane levels correlated with BMI, physical functioning, and medical comorbidity but not with severity of psychopathology or executive function. Linear models showed significant effects of diagnosis, gender, and BMI on F2-isoprostane levels, but no interactions.

DISCUSSION

Our finding of increased oxidative stress in schizophrenia is consistent with reports of increased morbidity and mortality as well as accelerated aging in schizophrenia. The significant associations between F2-isoprostane levels and both gender and BMI warrant further study.

Implications for reactive oxygen species in schizophrenia pathogenesis

Oxidative stress is a well-recognized participant in the pathophysiology of multiple brain disorders, particularly neurodegenerative conditions such as Alzheimer's and Parkinson's diseases. While not a dementia, a wide body of evidence has also been accumulating for aberrant reactive oxygen species and inflammation in schizophrenia. Here we highlight roles for oxidative stress as a common mechanism by which varied genetic and epidemiologic risk factors impact upon neurodevelopmental processes that underlie the schizophrenia syndrome. While there is longstanding evidence that schizophrenia may not have a single causative lesion, a common pathway involving oxidative stress opens the possibility for intervention at susceptible phases.

Relationship between neutrophil/lymphocyte ratio with oxidative stress and psychopathology in patients with schizophrenia

INTRODUCTION

The aim of our study was to evaluate the relationship between neutrophil/lymphocyte ratio (NLR) and total antioxidant status (TAS), total oxidative status (TOS), oxidative stress index (OSI), paraoxonase, and total thiol (T.thl) in schizophrenic patients compared to healthy control group and investigate the relationship between these parameters and psychopathological symptoms.

METHODS

The study population consisted of 61 healthy control subjects and 64 volunteer patients monitored in the outpatient clinics of psychiatry of Antalya Education and Research Hospital. Hemograms were determined by using a fully automated hematology analyzer (Beckman Coulter LH780). Serum TOS, TAS, paraoxonase, and T.thl were measured using a novel automated colorimetric measurement method developed by Erel. Sociodemographic data forms were completed by the participants. The Positive and Negative Syndrome Scale (PANSS) was used to assess the patients.

RESULTS

Neutrophils, NLR, TAS, and TOS significantly increased, whereas lymphocytes, T.thl, and T.thl/OSI ratio were significantly lower in the schizophrenia patient group compared to the control group. A statistically significant positive relationship was found between PANSS positive subscale with leukocytes and significantly negative relationships were found between PANSS positive subscale with lymphocytes and T.thl/OSI ratio. Significant positive relationships were found between PANSS total subscale with leukocytes and NLR. Statistically significant negative relationships were found between PANSS total subscale with lymphocytes and T.thl/OSI ratio. In the group of patients with schizophrenia, a significant negative correlation was found between NLR with T.thl/OSI. In the group of patients with schizophrenia, a significant positive correlation was found between NLR with TOS and OSI.

CONCLUSION

By measuring NLR, which is simple, inexpensive, and suitable for routine use, we can obtain information about oxidative stress and psychopathological symptoms in patients with schizophrenia. Inflammation and oxidative stress are important in the pathogenesis of schizophrenia and are closely related with the patients' clinical symptoms.

Increased oxidative stress and oxidative DNA damage in non-remission schizophrenia patients

Increasing evidence shows that oxidative stress plays a role in the pathophysiology of schizophrenia. But there is not any study which examines the effects of oxidative stress on DNA in schizophrenia patients. Therefore we aimed to assess the oxidative stress levels and oxidative DNA damage in schizophrenia patients with and without symptomatic remission. A total of 64 schizophrenia patients (38 with symptomatic remission and 26 without symptomatic remission) and 80 healthy volunteers were included in the study. 8-hydroxydeoxyguanosine (8-OHdG), total oxidant status (TOS) and total antioxidant status (TAS) were measured in plasma. TOS, oxidative stress index (OSI) and 8-OHdG levels were significantly higher in non-remission schizophrenic (Non-R-Sch) patients than in the controls. TOS and OSI levels were significantly higher in remission schizophrenic (R-Sch) patients than in the controls. TAS level were significantly lower and TOS and OSI levels were significantly higher in R-Sch patients than in Non-R-Sch patients. Despite the ongoing oxidative stress in patients with both R-Sch and Non-R-Sch, oxidative DNA damage was higher in only Non-R-Sch patients compared to controls. It is suggested that oxidative stress can cause the disease via DNA damage, and oxidative stress plays a role in schizophrenia through oxidative DNA damage.

Association of status redox with demographic, clinical and imaging parameters in patients with Huntington's disease

Huntington's disease (HD) is an autosomal dominant, progressive neurodegenerative disorder, caused by an expanded trinucleotide CAG sequence of the huntingtin (Htt) gene, which encodes a stretch of glutamines in the Htt protein. The mechanisms of neurodegeneration associated with the accumulation of Htt aggregates still remains unclear.

OBJECTIVES

To determine oxidative stress biomarkers in HD patients and their relationship with clinical, demographic and neuroimaging parameters.

DESIGN AND METHODS

Fourteen patients and 39 controls paired by age and sex participated in this study. Oxidative damage was assayed in blood by measuring malondialdehyde (MDA) and advanced oxidative protein products (AOPPs). Antioxidant status was determined by activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced glutathione (GSH), protein thiols and total antioxidant capacity (FRAP). The Unified Huntington Disease Rating Scale (UHDRS) and neuroimaging studies were also employed.

RESULTS

MDA, AOPP and GPx were significantly increased in HD patients with respect to the control group, while GR activity was decreased. FRAP correlated with age of disease onset, AOPP with motor severity (UHDRS score), age of patients and age of disease onset. Caudate atrophy was associated with lower plasma concentrations of GSH.

CONCLUSIONS

These findings point to a redox imbalance in HD patients. GR activity could be a potential biomarker for symptom onset in asymptomatic gene carriers, while plasmatic GSH could be useful in monitoring the progression of neurodegeneration - as an expression of caudate atrophy - during the course of the disease.

Psychiatric Disorders and Polyphenols: Can They Be Helpful in Therapy?

The prevalence of psychiatric disorders permanently increases. Polyphenolic compounds can be involved in modulation of mental health including brain plasticity, behaviour, mood, depression, and cognition. In addition to their antioxidant ability other biomodulating properties have been observed. In the pathogenesis of depression disturbance in neurotransmitters, increased inflammatory processes, defects in neurogenesis and synaptic plasticity, mitochondrial dysfunction, and redox imbalance are observed. Ginkgo biloba, green tea, and Quercus robur extracts and curcumin can affect neuronal system in depressive patients. ADHD patients treated with antipsychotic drugs, especially stimulants, report significant adverse effects; therefore, an alternative treatment is searched for. An extract from Ginkgo biloba and from Pinus pinaster bark, Pycnogenol, could become promising complementary supplements in ADHD treatment. Schizophrenia is a devastating mental disorder, with oxidative stress involved in its pathophysiology. The direct interference of polyphenols with schizophrenia pathophysiology has not been reported yet. However, increased oxidative stress caused by haloperidol was inhibited ex vivo by different polyphenols. Curcumin, extract from green tea and from Ginkgo biloba, may have benefits on serious side effects associated with administration of neuroleptics to patients suffering from schizophrenia. Polyphenols in the diet have the potential to become medicaments in the field of mental health after a thorough study of their mechanism of action.

Role of nitric oxide and related molecules in schizophrenia pathogenesis: biochemical, genetic and clinical aspects

Currently, schizophrenia is considered a multifactorial disease. Over the past 50 years, many investigators have considered the role of toxic free radicals in the etiology of schizophrenia. This is an area of active research which is still evolving. Here, we review the recent data and current concepts on the roles of nitric oxide (NO) and related molecules in the pathogenesis of schizophrenia. NO is involved in storage, uptake and release of mediators and neurotransmitters, including glutamate, acetylcholine, noradrenaline, GABA, taurine and glycine. In addition, NO diffuses across cell membranes and activates its own extrasynaptic receptors. Further, NO is involved in peroxidation and reactive oxidative stress. Investigations reveal significant disturbances in NO levels in the brain structures (cerebellum, hypothalamus, hippocampus, striatum) and fluids of subjects with schizophrenia. Given the roles of NO in central nervous system development, these changes may result in neurodevelopmental changes associated with schizophrenia. We describe here the recent literature on NOS gene polymorphisms on schizophrenia, which all point to consistent results. We also discuss how NO may be a new target for the therapy of mental disorders. Currently there have been 2 randomized double-blind placebo-controlled trials of L-lysine as an NOS inhibitor in the CNS.

Antipsychotic-like effect of trimetazidine in a rodent model

Trimetazidine (TMZ) has been used as an anti-ischemic agent for angina pectoris, chorioretinal disturbances, and vertigo. Also, it can induce extrapyramidal type adverse reaction such as parkinsonism, gait disorder, and tremor via blockade of D2 receptors. In the present study, we evaluated the effect of TMZ on novelty-induced rearing behavior and apomorphine-induced stereotypy behavior in male rats. Four groups of rat (n = 7) were administrated with TMZ (10 and 20 mg/kg, i.p.), chlorpromazine (1 mg/kg, i.p.), or isotonic saline. One hour later, apomorphine (2 mg/kg, s.c.) was administrated to each rat. Our results showed that both doses of TMZ significantly decreased the rearing behavior in rats, whereas the decrease with chlorpromazine was higher. TMZ also decreased the stereotypy scores in a dose-dependent manner. We concluded that TMZ has beneficial effects on rearing behavior and stereotypy, which are accepted to be indicators of antipsychotic effect. Taken together, with its antioxidative and cytoprotective properties, TMZ is worthy of being investigated for its anti-psychotic effects as a primary or an adjunctive drug.

Meta-analysis of oxidative stress in schizophrenia

BACKGROUND

Schizophrenia is associated with impaired antioxidant defense, including abnormal serum, plasma, and red blood cell (RBC) oxidative stress parameters. We performed a meta-analysis of these associations, considering the effect of clinical status and antipsychotic treatment after an acute exacerbation of psychosis.

METHODS

We identified articles by searching PubMed, PsychInfo, and Institute for Scientific Information, and the reference lists of identified studies.

RESULTS

Forty-four studies met the inclusion criteria. Total antioxidant status seemed to be a state marker, because levels were significantly decreased in cross-sectional studies of serum and plasma in first-episode psychosis (FEP) and significantly increased in longitudinal studies of antipsychotic treatment for acute exacerbations of psychosis (p < .01 for each). The RBC catalase and plasma nitrite seemed to be state-related markers, because levels in cross-sectional studies were significantly decreased in FEP (p < .01) and significantly increased in stable outpatients (p = .01). In contrast, RBC superoxide dismutase seemed to be a trait marker for schizophrenia, because levels in cross-sectional studies were significantly decreased in acutely relapsed inpatients, FEP, and stable outpatients (p < .01 for each).

CONCLUSIONS

Oxidative stress abnormalities in FEP suggest an effect that might be independent of antipsychotic medications. Although some parameters (total antioxidant status, RBC catalase, and plasma nitrite) might be state markers for acute exacerbations of psychosis, others (RBC superoxide dismutase) might be trait markers; however, more longitudinal studies are needed. Our findings suggest that oxidative stress might serve as a potential biomarker in the etiopathophysiology and clinical course of schizophrenia.

Reduced total antioxidant level and increased oxidative stress in patients with deficit schizophrenia: a preliminary study

INTRODUCTION

Deficit schizophrenia (DS) is defined for identifying a relatively homogeneous subgroup of patients with diagnosis of schizophrenia, characterized by the presence of primary and enduring negative symptoms. There have been several studies which investigated the status of oxidative stress and total antioxidant level in patients with schizophrenia. However, there is not any study which researched differences between DS and nondeficit schizophrenia (NDS) in terms of status of oxidative stress and antioxidant level. We hypothesized that patients with DS would have different status of oxidative stress and antioxidant levels compared with patients with NDS.

METHODS

Twenty-three patients with DS, 42 patients with NDS and 31 age, sex and smoking status matched healthy controls (HC) were included to study. Five milliliters of blood was drawn from control subjects and patients for assessing total antioxidant potential (TAOP) and total peroxide levels (TPEROX). The ratio of TPEROX to TAOP is referred as oxidative stress index (OSI).

RESULTS

We noticed that serum TAOP level was significantly lower in DS group compared with NDS and HC groups. The OSI was also found to be higher in DS group compared with NDS and HC groups. Furthermore, serum TAOP level and status of OSI were similar between NDS and HC groups.

CONCLUSION

Our study is the first to demonstrate differences between DS and NDS in terms of status of oxidative stress and serum total antioxidant level. We suggest that our study represents novel and important results in terms of supporting provides and hypothesis which considered DS as a different disease entity with respect to NDS. Further studies are needed for investigating the status of antioxidants and oxidative stress and their clinical implications in deficit schizophrenia.

Sex differences in lipid peroxidation and fatty acid levels in recent onset schizophrenia

Sex differences in the symptomatology and course of illness have been reported among schizophrenic patients. Hence, the principal objective of the present study was to investigate sex differences in the concentrations of the lipid peroxidation metabolites MDA and 4-HNE, and in the membrane phospholipid levels of ARA, EPA and DHA in patients with schizophrenia. A total of 46 paranoid schizophrenics (25 women) with short-term evolution who were in an acute psychotic stage and 40 healthy controls (23 women) participated in the study. Psychopathology was evaluated by BPRS and PANSS. Lipid peroxidation sub-products (MDA, 4-HNE) and fatty acid levels (ARA, EPA, DHA) were determined in erythrocyte membranes. The men in both groups showed higher lipid peroxidation levels and those values were higher in schizophrenic patients than controls, with only EPA fatty acid concentrations found to be lower in the former than the latter. These results suggest that men may suffer greater oxidative neuronal damage than women, and that this could worsen the course of illness and result in greater disease severity.

Plasma total antioxidant status and cognitive impairments in schizophrenia

Oxidative stress-induced damage to neurons may contribute to cognitive deficits during aging and in neurodegenerative disorders. Schizophrenia has a range of cognitive deficits that may evolve from oxidative stress, and this study examines this association of oxidative stress with cognitive deficits in schizophrenia. We recruited 296 chronic schizophrenia patients and 181 healthy control subjects and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and plasma total antioxidant status (TAS) in both groups. Schizophrenia symptoms were assessed using the positive and negative syndrome scale (PANSS). Our results showed that TAS levels were significantly lower in patients than controls (179.6 ± 81.0 U/ml vs. 194.8 ± 46.0 U/ml, p<0.05). Cognitive scores on the RBANS and nearly all of its five subscales (all p<0.001) except for the Visuospatial/Constructional index (p>0.05) were significantly lower in schizophrenia patients than normal controls. For the patients, TAS was inversely associated with some domains of cognitive deficits in schizophrenia, such as Attention and Immediate Memory. Our findings suggest that oxidative stress may be involved in the pathophysiology of schizophrenia, and its associated cognitive impairment.

Plasma antioxidant capacity is reduced in Asperger syndrome

Recent evidence suggests that children with autism have impaired detoxification capacity and may suffer from chronic oxidative stress. To our knowledge, there has been no study focusing on oxidative metabolism specifically in Asperger syndrome (a milder form of autism) or comparing this metabolism with other psychiatric disorders. In this study, total antioxidant status (TAOS), non-enzymatic (glutathione and homocysteine) and enzymatic (catalase, superoxide dismutase, and glutathione peroxidase) antioxidants, and lipid peroxidation were measured in plasma or erythrocyte lysates in a group of adolescent patients with Asperger syndrome, a group of adolescents with a first episode of psychosis, and a group of healthy controls at baseline and at 8-12 weeks. TAOS was also analyzed at 1 year. TAOS was reduced in Asperger individuals compared with healthy controls and psychosis patients, after covarying by age and antipsychotic treatment. This reduced antioxidant capacity did not depend on any of the individual antioxidant variables measured. Psychosis patients had increased homocysteine levels in plasma and decreased copper and ceruloplasmin at baseline. In conclusion, Asperger patients seem to have chronic low detoxifying capacity. No impaired detoxifying capacity was found in the first-episode psychosis group in the first year of illness.

Reduced serum non-enzymatic antioxidant defense and increased lipid peroxidation in schizophrenic patients on a hypocaloric diet

INTRODUCTION

Growing evidence suggests that oxidative stress (OS) may be associated with the pathophysiology underlying schizophrenia (SZ). Some studies indicate that nutritional supplements offer protection from OS, but there is no data about the effect of a hypocaloric diet on OS in this population. Therefore, we aimed to study the effect of a hypocaloric dietary intervention on OS in subjects with SZ.

METHODS

A cross-sectional study of 96 participants in outpatient treatment for SZ comprised patients separated into two groups: one group of subjects followed a hypocaloric diet (HD) program (n=42), while the other group followed a regular diet (RD) with no nutritional restrictions (n=54). The serum total radical-trapping antioxidant parameter (TRAP), total antioxidant reactivity (TAR) and thiobarbituric acid reactive species (TBARS) levels were assessed.

RESULTS

TRAP levels were lower and TBARS levels were higher in the HD group than in the RD group (p=0.022 and p=0.023, respectively). There were no differences in TAR levels between the groups. Additionally, there was a positive correlation between TRAP and TBARS levels after adjusting for BMI and clozapine dose (partial correlation=0.42, p<0.001). There were no correlations among the length of illness or diet and the levels of TRAP, TBARS, and TAR.

CONCLUSIONS

Subjects with SZ on a hypocaloric diet displayed different OS parameters than those not following a HD. Serum TRAP levels were lower and TBARS levels were higher among SZ subjects with HD compared to SZ subjects without HD. Lower TRAP levels may reflect decreased oxidative stress, whereas higher TBARS levels most likely reflect a biochemical reaction to the decreased TRAP levels. Additionally, TAR levels were similar between groups, suggesting a similar quality of antioxidant defenses, despite quantitative differences between the two dietary protocols in SZ patients under outpatient care.

Evidence of aberrant DNA damage response signalling but normal rates of DNA repair in dividing lymphoblasts from patients with schizophrenia

OBJECTIVES

Cancer incidence in schizophrenia is not increased commensurate with higher rates of risk exposures. Here we report an investigation of the DNA damage response, an anti-tumorigenic defence, in immortalised lymphoblasts from patients with schizophrenia.

METHODS

Unirradiated and irradiated (5Gy) lymphoblasts from schizophrenia patients (n = 28) and healthy controls (n = 28) were immunostained for the phosphorylated histone variant H2AX (γH2AX), an index of DNA double-strand breaks. Flow cytometry was used to assess cell cycle distribution and γH2AX immunofluorescence. Rate of DNA repair was quantified by determining the temporal change in γH2AX values following irradiation.

RESULTS

In unirradiated lymphoblasts, γH2AX levels were significantly increased in the schizophrenia group compared with controls (effect size = 0.86). This increase was most evident in patients with cognitive deficits. In irradiated lymphoblasts, peak radiation-induced γH2AX levels were significantly reduced in patients. No differences between patients and controls were found in the rate of DNA repair or in cell cycle distribution.

CONCLUSIONS

The significant differences in DNA damage response signalling observed involve modification of histone variant H2AX and thereby implicate regulatory processes determining chromatin structure in dividing lymphoblasts from patients with schizophrenia. The role that aberrant DNA damage response signalling plays in protecting patients from cancer is unclear.

Elevated plasma superoxide dismutase in first-episode and drug naive patients with schizophrenia: inverse association with positive symptoms

Excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased superoxide dismutase (SOD) activities, a critical enzyme in the detoxification of superoxide radicals. This study compared plasma SOD activities in 78 never-medicated first-episode and 100 medicated chronic schizophrenia patients to 100 healthy control subjects and correlated these SOD activities with the Positive and Negative Syndrome Scale (PANSS) among the schizophrenic patients. We found that both first-episode and chronic patients had significantly increased plasma SOD activities compared to controls, and that chronic schizophrenic patients on antipsychotic medication had significantly higher SOD activities than first episode schizophrenic patients. Plasma SOD activities were also negatively correlated with positive symptoms of schizophrenia, but only in first-episode patients. Thus, oxidative stress appears to be greater in first episode schizophrenic patients with fewer positive symptoms and may become greater as schizophrenia becomes more chronic, although we cannot exclude the possibility that chronic antipsychotic treatment may increase SOD activities and presumed oxidative stress in schizophrenia.