The relationship between potency of oxidative stress and severity of depression

Associations of serum uric acid and SLC2A9 variant with depressive and anxiety disorders: a population-based study

BACKGROUND

Limited information exists regarding the association between serum uric acid (SUA) and psychiatric disorders. We explored the relationship between SUA and subtypes of major depressive disorder (MDD) and specific anxiety disorders. Additionally, we examined the association of SLC2A9 rs6855911 variant with anxiety disorders.

METHODS

We conducted a cross-sectional analysis on 3,716 individuals aged 35-66 years previously selected for the population-based CoLaus survey and who agreed to undergo further psychiatric evaluation. SUA was measured using uricase-PAP method. The French translation of the semi-structured Diagnostic Interview for Genetic Studies was used to establish lifetime and current diagnoses of depression and anxiety disorders according to the DSM-IV criteria.

RESULTS

Men reported significantly higher levels of SUA compared to women (357±74 µmol/L vs. 263±64 µmol/L). The prevalence of lifetime and current MDD was 44% and 18% respectively while the corresponding estimates for any anxiety disorders were 18% and 10% respectively. A quadratic hockey-stick shaped curve explained the relationship between SUA and social phobia better than a linear trend. However, with regards to the other specific anxiety disorders and other subtypes of MDD, there was no consistent pattern of association. Further analyses using SLC2A9 rs6855911 variant, known to be strongly associated with SUA, supported the quadratic relationship observed between SUA phenotype and social phobia.

CONCLUSIONS

A quadratic relationship between SUA and social phobia was observed consistent with a protective effect of moderately elevated SUA on social phobia, which disappears at higher concentrations. Further studies are needed to confirm our observations.

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

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

Aspirin: a review of its neurobiological properties and therapeutic potential for mental illness

There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory 'braking signals', including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor-α and interleukin (IL)--6, but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.

Oxidative stress and glutathione response in tissue cultures from persons with major depression

There is evidence that major depressive disorder (MDD) is associated with increased peripheral markers of oxidative stress. To explore oxidation and antioxidant response in MDD, we assayed human dermal fibroblast cultures derived from skin biopsies of age-, race-, and sex-matched individuals in depressed and normal control groups (n = 16 each group), cultured in glucose and galactose conditions, for relative protein carbonylation (a measure of oxidative stress), glutathione reductase (GR) expression, and total glutathione concentration. In control-group fibroblasts, galactose induced a significant increase from the glucose condition in both protein carbonylation and GR. The cells from the MDD group showed total protein carbonylation and GR expression in the glucose condition that was significantly higher than control cells in glucose and equivalent to controls in galactose. There was a small decrease in protein carbonylation in MDD cells from glucose to galactose and no significant change in GR. There was no difference in total glutathione among any of the groups. Increased protein carbonylation and GR expression, cellular responses to oxidative stress induced by galactose in control fibroblasts, are present in fibroblasts derived from MDD patients and are not explainable by reduced GR or total glutathione in the depressed patients. These studies support the role of oxidative stress in the pathophysiology of MDD. Further confirmation of these findings could lead to the development of novel antioxidant approaches for the treatment of depression.

Taurine and glutathione levels in plasma before and after ECT treatment

Taurine has been shown to be elevated in plasma and lymphocytes of depressed patients, but the level normalises after successful drug therapy. During depression, levels of glutathione (GSH) are decreased in the plasma and blood. This study was performed to examine taurine and GSH levels in depressed patients before and after electroconvulsive therapy (ECT). Fasting blood samples were collected from 23 patients before the first and after the third ECT treatment. The severity of depression was estimated with the Montgomery-Åsberg Depression Rating Scale (MADRS). We analysed GSH in blood and the levels of taurine and total GSH in plasma. After three ECTs, a significant decrease in MADRS scores was found for the entire group. Simultaneously, the decrease in the plasma taurine levels was significant for the seven responders but not for the sixteen non-responders. We observed no differences in blood or plasma GSH levels after three ECT treatments when compared to values before the therapy. Plasma taurine levels decrease significantly after three ECT treatments in patients who respond to treatment. GSH levels were not affected by ECT treatment. The results indicate that taurine may play a role in the pathophysiology of depression.

Curcumin ameliorates reserpine-induced pain-depression dyad: behavioural, biochemical, neurochemical and molecular evidences

An apparent clinical relationship between pain and depression has long been recognized. Depression and pain are often diagnosed in the same patients. The emerging concept for pain-depression pathogenesis is the dysfunction of biogenic amine-mediated pain-depression control and the possible involvement of nitrodative stress-induced neurogenic inflammation. The present study was designed to investigate the effect of curcumin on reserpine-induced pain-depression dyad in rats. Administration of reserpine (1mg/kg subcutaneous daily for three consecutive days) led to a significant decrease in nociceptive threshold as evident from reduced paw withdrawal threshold in Randall Sellitto and von-Frey hair test as well as significant increase in immobility time in forced swim test. This behavioural deficit was integrated with decrease in the biogenic amine (dopamine, norepinephrine and serotonin) levels along with increased substance P concentration, nitrodative stress, inflammatory cytokines, NF-κβ and caspase-3 levels in different brain regions (cortex and hippocampus) of the reserpinised rats. Curcumin (100, 200, 300mg/kg; ip) dose dependently ameliorated the behavioural deficits associated with pain and depression by restoring behavioural, biochemical, neurochemical and molecular alterations against reserpine-induced pain-depression dyad in rats.

Expression of oxidative stress-response genes is not activated in the prefrontal cortex of patients with depressive disorder

To test the hypothesis that the oxidative stress consistently detected in the peripheral blood of patients with depressive disorder impacts on the functionally relevant brain region, the expression level of nine major genes of the stress response and repair systems has been quantified in the prefrontal cortex of 24 depressive and 12 control subjects. These genes were: superoxide dismutase (SOD1), SOD2, catalase (CAT), gluthatione peroxidase 1 (GPx1), 8-oxoguanine DNA glycosylase (OGG1), nei-like 1 (NEIL1), methionine sulphoxide reductase A (MSRA), telomere repeat-binding factor 2 (TERF2) and C-FOS. Telomere length (a maker of chronic exposure to oxidative stress) has been measured in the DNA of the occipital cortex. No significant difference has been found between the compared groups. It must be concluded that the pathogenic role of the oxidative stress in the cerebral mechanism of depression cannot be inferred from the alteration of peripheral parameters.

Analysis of plasma zinc and copper concentration, and perceived symptoms, in individuals with depression, post zinc and anti-oxidant therapy

AIM

To assess plasma Zn and Cu levels in individuals with depression.

SUBJECTS AND METHODS

Plasma from 73 clinically depressed individuals, 38 individuals with anxiety and 16 controls were tested for plasma Zn and Cu concentration using inductively-coupled plasma-mass spectrometry.

RESULTS

Depressed individuals, with and without secondary anxiety, had decreased plasma Zn and elevated plasma Cu compared to controls. Zn normalized (increased to the level of normal controls) but Cu increased in individuals with depression (with and without secondary anxiety), after Zn therapy, whereas both plasma Zn increased and Cu levels decreased in anxiety, with and without secondary depression, after Zn therapy. Individuals with depression,with and without secondary anxiety, had significantly higher symptom severity when compared to neurotypical controls. Symptom severity in individuals with anxiety (both with and without secondary depression) significantly decreased after Zn therapy, whereas symptoms remained the same in individuals with primary depression.

DISCUSSION

These data show an association between Zn and Cu plasma levels and clinically depressed individuals, and suggest that high Cu levels are associated with high symptom severity.

Decreased levels of glutathione, the major brain antioxidant, in post-mortem prefrontal cortex from patients with psychiatric disorders

Accruing data suggest that oxidative stress may be a factor underlying the pathophysiology of bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SCZ). Glutathione (GSH) is the major free radical scavenger in the brain. Diminished GSH levels elevate cellular vulnerability towards oxidative stress; characterized by accumulating reactive oxygen species. The aim of this study was to determine if mood disorders and SCZ are associated with abnormal GSH and its functionally related enzymes. Post-mortem prefrontal cortex from patients with BD, MDD, SCZ, and from non-psychiatric comparison controls were provided by the Stanley Foundation Neuropathology Consortium. Spectrophotometric analysis was utilized for the quantitative determination of GSH, while immunoblotting analyses were used to examine expression of glutamyl-cysteine ligase (GCL), GSH reductase (GR), and GSH peroxidase (GPx). We found that the levels of reduced, oxidized, and total GSH were significantly decreased in all psychiatric conditions compared to the control group. Although GCL and GR levels did not differ between groups, the levels of GPx were reduced in MDD and SCZ compared to control subjects. Since oxidative damage has been demonstrated in MDD, BD, and SCZ, our finding that GSH levels are reduced in post-mortem prefrontal cortex suggests that these patient groups may be more susceptible to oxidative stress.

Tobacco smoking as a risk factor for depression. A 26-year population-based follow-up study

BACKGROUND

A key question regarding the documented association between smoking and depression is whether it reflects a causal influence of smoking on depression; however, only a limited number of longitudinal studies exist in the literature, all of which have relatively short time frames. The purpose was to prospectively assess the risk of depression according to daily tobacco consumption in a Danish longitudinal study.

METHODS

A prospective cohort study, the Copenhagen City Heart Study (n = 18,146), was analyzed with up to 26 years of follow-up. It contains three updated data sets on tobacco consumption and potential confounding factors. The study population was linked to Danish hospital registers to detect registrations with depression. Individuals with depression before baseline were excluded.

RESULTS

Women smoking more than 10 g of tobacco per day were at significantly increased risk of depression compared to women who did not smoke. The adjusted risk of depression among women smoking 11-20 g per day was 1.74 (CI:1.33-2.27) and 2.17 (CI:1.45-3.26) among women smoking more than 20 g per day. For men, there was an increased risk of depression for those smoking more than 20 g per day (HR = 1.90; CI:1.05-3.44). All tests for linear trend were significant (all p < 0.01). The estimates remained significant in sensitivity analyses aiming to eliminate reverse causation, and in analyses based on a reduced sample without individuals with chronic diseases or psychiatric disorders other than depression.

CONCLUSION

The study suggests that smoking is associated with increased risk of developing depression. This underlines the potentially harmful consequences of smoking for mental health and supports efforts to prevent and stop smoking.

Functional polymorphism of the myeloperoxidase gene (G-463A) in depressive patients

Gałecki P, Florkowski A, Bobińska K, Śmigielski J, Bieńkiewicz M, Szemraj J. Functional polymorphism of the myeloperoxidase gene (G-463A) in depressive patients.

OBJECTIVE

Myeloperoxidase (MPO) is an enzyme involved in the production of hypochloric acid as well as other reactive oxygen species. This enzyme plays a significant role in inflammatory processes. In view of the observed associations between depression and such inflammatory processes, as well as of the reports that confirm the presence of oxidative stress in depression, this study was designed to assess the correlation, if any, between the single nucleotide polymorphism G-463A of the MPO gene and the risk of recurrent depressive disorders (DD).

METHODS

The study was carried out in a group of 149 patients with recurrent DD and 149 healthy control subjects. Genotyping was performed by PCR/restriction fragment length polymorphism.

RESULTS

A comparison between healthy controls and depressive patients showed a statistically significant difference in genotype distribution and allele frequency in the studied groups. Genotype distribution and allele frequency did not correlate with clinical variables of the patients.

CONCLUSION

The obtained results of the study allow us to draw a cautious conclusion about the role of the analysed G-463A MPO polymorphism in recurrent DD development, which, however, requires eventual confirmation in further studies.

Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Depression Correlates with Severity of Disease

AIM

To assess serum Hepatocyte Growth Factor (HGF) levels in individuals with depression and to test the hypothesis that there is a relationship between severity of depression and HGF concentration.

SUBJECTS AND METHODS

Serum from 26 clinically depressed individuals and 19 controls were tested for serum HGF using ELISAs. Correlation was established between HGF concentration and disease severity.

RESULTS

Depressed individuals had significantly lower serum levels of HGF compared to controls (P < 0.0001). HGF concentration correlated with overall depressive behavior (P = 0.03) and specifically depression (P = 0.02), but not anxiety (P = 0.36).

DISCUSSION

These results suggest an association between HGF serum levels and clinically depressed individuals and demonstrate a correlation between severity of depression and HGF levels. Further studies of the predictive strength of HGF as a biomarker for depression may be warranted.

Clinical correlation of alteration of endogenous antioxidant-uric acid level in major depressive disorder

Derangement of antioxidant levels in major depressive disorder had been correlated with oxidative damage. The effect of Selective Serotonin Re-Uptake Inhibitors on endogenous antioxidant uric acid levels in major depressive disorder has never been examined. This was a prospective; open labeled, parallel, 12 weeks study, in which serum uric acid levels and Hamilton Rating Scale for Depression score were estimated in age and sex matched thirty-six healthy and forty major depressive disorder subjects before and after fluoxetine and citalopram treatment. Significant decrease in serum uric acid (P<0.0001) was observed in newly diagnosed major depressive disorder subjects when compared to healthy subjects. The trend was reversed after 6 weeks more significantly after 12 weeks of treatment with improvement in Hamilton Rating Scale for Depression score. Also, Significant and negative correlation was found between Hamilton Rating Scale for Depression score and serum uric acid level (r= -0.864, P<0.001) after 12 weeks of treatment. Treatment with fluoxetine or citalopram reverses endogenous antioxidants like uric acid and improves Hamilton Rating Scale for Depression score in major depressive disorder.

alpha-Tocopherol administration produces an antidepressant-like effect in predictive animal models of depression

This study investigated the antidepressant potential of alpha-tocopherol, the most active and abundant form of vitamin E, in the forced swim test (FST) and tail suspension test (TST). The acute oral treatment with alpha-tocopherol at the doses of 30 and 100mg/kg reduced the immobility time in the FST and in the TST. A single i.c.v. administration of alpha-tocopheryl phosphate, a water-soluble analogue of alpha-tocopherol, also reduced the immobility time in the FST (0.1 and 1 nmol/site) and in the TST (0.1 nmol/site). In addition, the long-term treatment (28 days) with alpha-tocopherol (10mg/kg, p.o.) significantly reduced the immobility time in the FST. Moreover, a subeffective dose of alpha-T (10mg/kg, p.o.) potentiated the effect of fluoxetine (10mg/kg, p.o.) in the FST. The long-term treatment with alpha-T was able to increase the glutathione (GSH) antioxidant defense system, while the acute treatment was not. The long-term treatment with alpha-tocopherol (10mg/kg) increased the GSH levels in the hippocampus and in the prefrontal cortex and increased the glutathione peroxidase and glutathione reductase activity in the hippocampus (10mg/kg) and in the prefrontal cortex (10-100mg/kg). The long-term treatment with fluoxetine (10mg/kg, p.o.), a positive control, was also able to increase the GSH levels in the hippocampus, but failed to alter the activity of both enzymes. Besides the specific antidepressant-like effect, long-term, but not the acute treatment with alpha-T, especially in the doses that produced an antidepressant-like effect (10mg/kg), improved the antioxidant defenses in the mouse hippocampus and prefrontal cortex, two structures closely implicated in the pathophysiology of depression.

Oxidative imbalance in bipolar disorder subtypes: a comparative study

OBJECTIVE

The oxidants are related with the membrane-associated pathologies in the central nervous system and may have an important role in neuropsychiatric disorders. Several studies were performed on the effects of free radicals in bipolar disorder. However, there are no studies investigating the effects of free radicals both in the subtypes of BD (Bipolar disorders I and II) and in antidepressant induced mania (AIM). In this study, we aimed to investigate the status of oxidative metabolism in BD and its subtypes.

METHODS

94 bipolar patients (BD I-II and AIM) diagnosed according to DSM IV and as control group 41 healthy subjects were included to the study. The total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) were examined in the properly obtained plasma samples of subjects and healthy controls included in the study.

RESULTS

The patients' TAS, TOS and OSI were significantly higher than the controls. TAS is negatively correlated with the number of previous total episodes in BD I. The BD I group appeared to have higher TOS compared to BD II group.

CONCLUSIONS

Oxidative balance is impaired in bipolar disorder. Antioxidant levels may be increased compensatorily in response to increased oxidant levels. Another important result of our study was that in the comparison of the three disease subtypes BD I group was found to have higher TOS compared to the BD II group. This finding is compatible with the literature on BD I and may be associated with the more severe course of BD I.

The association between dietary patterns and mental health in early adolescence

OBJECTIVE

To investigate the associations between dietary patterns and mental health in early adolescence.

METHOD

The Western Australian Pregnancy Cohort (Raine) Study is a prospective study of 2900 pregnancies recruited from 1989-1992. At 14 years of age (2003-2006; n=1324), the Child Behaviour Checklist (CBCL) was used to assess behaviour (characterising mental health status), with higher scores representing poorer behaviour. Two dietary patterns (Western and Healthy) were identified using factor analysis and food group intakes estimated by a 212-item food frequency questionnaire. Relationships between dietary patterns, food group intakes and behaviour were examined using general linear modelling following adjustment for potential confounding factors at age 14: total energy intake, body mass index, physical activity, screen use, family structure, income and functioning, gender and maternal education at pregnancy.

RESULTS

Higher total (b=2.20, 95% CI=1.06, 3.35), internalizing (withdrawn/depressed) (b=1.25, 95% CI=0.15, 2.35) and externalizing (delinquent/aggressive) (b=2.60, 95% CI=1.51, 3.68) CBCL scores were significantly associated with the Western dietary pattern, with increased intakes of takeaway foods, confectionary and red meat. Improved behavioural scores were significantly associated with higher intakes of leafy green vegetables and fresh fruit (components of the Healthy pattern).

CONCLUSION

These findings implicate a Western dietary pattern in poorer behavioural outcomes for adolescents. Better behavioural outcomes were associated with a higher intake of fresh fruit and leafy green vegetables.

Comparison of oxidative stress among migraineurs, tension-type headache subjects, and a control group

BACKGROUND

A primary headache, particularly migraine, is associated with oxidative stress during the attack. However, data regarding the interictal state in migraineurs and in those with tension-type headache (TTH) is limited.

OBJECTIVES

(1) To assess the oxidative stress in migraineurs and TTH subjects in between the episodes and (2) to see if there is a difference in the degree of oxidative stress in the different subtypes of migraine and TTH.

MATERIALS AND METHODS

Fifty migraineurs, 50 patients with TTH, and 50 control subjects were included in this study after screening for the exclusion criteria. Diagnosis of headache was made according to the International Classification of Headache Disorders (ICHD)-2 criteria. A venous blood sample was collected from the antecubital vein at least 3 days after the last attack of headache. The sample was centrifuged immediately and the plasma was stored at -70 degrees C. The ferric reducing activity of plasma (FRAP) and the malondialdehyde (MDA) levels were assessed using colorimetric methods. Statistical analysis was done with the help of SPSS for Windows, v 11.0. One way ANOVA with post hoc Tukey test, independent sample t test, univariate regression, and multivariate regression analysis were done as indicated.

RESULTS

Migraineurs had higher values of MDA and FRAP than the subjects in the other two groups (P<0.001). No difference was observed between the TTH group and the control group. FRAP levels were significantly higher in subjects who had mixed migraine (migraine with aura and without aura) as compared to those with only migraine without aura (mean difference 196.1; 95% CI = 27.3 to 364.9; P = 0.01). Similarly, oxidative stress was significantly higher in patients with episodic TTH as compared to those with chronic TTH (FRAP t = 3.16; P = 0.003 and MDA t = 2.75; P = 0.008).

CONCLUSIONS

This study suggests that oxidative stress continues even between headache episodes in migraineurs but not in those with TTH. This could probably be consequent to the different pathophysiological mechanisms of TTH and migraine.

Monoamine oxidase inactivation: from pathophysiology to therapeutics

Monoamine oxidases (MAOs) A and B are mitochondrial bound isoenzymes which catalyze the oxidative deamination of dietary amines and monoamine neurotransmitters, such as serotonin, norepinephrine, dopamine, beta-phenylethylamine and other trace amines. The rapid degradation of these molecules ensures the proper functioning of synaptic neurotransmission and is critically important for the regulation of emotional behaviors and other brain functions. The byproducts of MAO-mediated reactions include several chemical species with neurotoxic potential, such as hydrogen peroxide, ammonia and aldehydes. As a consequence, it is widely speculated that prolonged excessive activity of these enzymes may be conducive to mitochondrial damages and neurodegenerative disturbances. In keeping with these premises, the development of MAO inhibitors has led to important breakthroughs in the therapy of several neuropsychiatric disorders, ranging from mood disorders to Parkinson's disease. Furthermore, the characterization of MAO knockout (KO) mice has revealed that the inactivation of this enzyme produces a number of functional and behavioral alterations, some of which may be harnessed for therapeutic aims. In this article, we discuss the intriguing hypothesis that the attenuation of the oxidative stress induced by the inactivation of either MAO isoform may contribute to both antidepressant and antiparkinsonian actions of MAO inhibitors. This possibility further highlights MAO inactivation as a rich source of novel avenues in the treatment of mental disorders.

Tobacco smoking as a risk factor for major depressive disorder: population-based study

BACKGROUND

Smoking is disproportionately prevalent among people with psychiatric illness.

AIMS

To investigate smoking as a risk factor for major depressive disorder.

METHOD

A population-based sample of women was studied using case-control and retrospective cohort study designs. Exposure to smoking was self-reported, and major depressive disorder diagnosed using the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP).

RESULTS

Among 165 people with major depressive disorder and 806 controls, smoking was associated with increased odds for major depressive disorder (age-adjusted odds ratio (OR)=1.46, 95% CI 1.03-2.07). Compared with non-smokers, odds for major depressive disorder more than doubled for heavy smokers (>20 cigarettes/day). Among 671 women with no history of major depressive disorder at baseline, 13 of 87 smokers and 38 of 584 non-smokers developed de novo major depressive disorder during a decade of follow-up. Smoking increased major depressive disorder risk by 93% (hazard ratio (HR)=1.93, 95% CI 1.02-3.69); this was not explained by physical activity or alcohol consumption.

CONCLUSIONS

Evidence from cross-sectional and longitudinal data suggests that smoking increases the risk of major depressive disorder in women.

Oxidative stress in psychiatric disorders: evidence base and therapeutic implications

Oxidative stress has been implicated in the pathogenesis of diverse disease states, and may be a common pathogenic mechanism underlying many major psychiatric disorders, as the brain has comparatively greater vulnerability to oxidative damage. This review aims to examine the current evidence for the role of oxidative stress in psychiatric disorders, and its academic and clinical implications. A literature search was conducted using the Medline, Pubmed, PsycINFO, CINAHL PLUS, BIOSIS Preview, and Cochrane databases, with a time-frame extending to September 2007. The broadest data for oxidative stress mechanisms have been derived from studies conducted in schizophrenia, where evidence is available from different areas of oxidative research, including oxidative marker assays, psychopharmacology studies, and clinical trials of antioxidants. For bipolar disorder and depression, a solid foundation for oxidative stress hypotheses has been provided by biochemical, genetic, pharmacological, preclinical therapeutic studies and one clinical trial. Oxidative pathophysiology in anxiety disorders is strongly supported by animal models, and also by human biochemical data. Pilot studies have suggested efficacy of N-acetylcysteine in cocaine dependence, while early evidence is accumulating for oxidative mechanisms in autism and attention deficit hyperactivity disorder. In conclusion, multi-dimensional data support the role of oxidative stress in diverse psychiatric disorders. These data not only suggest that oxidative mechanisms may form unifying common pathogenic pathways in psychiatric disorders, but also introduce new targets for the development of therapeutic interventions.

Increased oxidative stress and its relation with collagen metabolism in knee osteoarthritis

The purpose of this study was to determine serum oxidative/antioxidative status in patients with knee osteoarthritis and its relation with prolidase activity, which plays an important role in collagen metabolism. Serum antioxidative status was evaluated by measuring total antioxidant capacity (TAC), thiol level and catalase enzyme activity in patients with osteoarthritis and in healthy controls. Serum oxidative status was evaluated by measuring total peroxide (TP) and lipid hydroperoxide. Oxidative stress index (OSI) was calculated. Prolidase enzyme activity was measured to investigate the collagen metabolism. Serum TAC, thiol level, catalase activity and prolidase activity were significantly lower in patients than in controls (P < 0.001, for all). In contrast, TP, lipid hydroperoxide and OSI values were significantly higher in patients than in controls (P < 0.001 for all). Further, prolidase activity was negatively correlated with TP and OSI, and positively correlated with TAC. The present results indicate that the oxidant parameters increased and antioxidant parameters decreased in patients with osteoarthritis; therefore, these patients may be exposed to a potent oxidative stress. Decreased collagen metabolism may be related with oxidative stress, which has a role in the ethiopathogenesis and/or in the progression of the disease.

Total antioxidant capacity and the severity of the pain in patients with fibromyalgia

The purpose of the study was to determine the oxidative and antioxidative status of plasma in patients with fibromyalgia. Total antioxidant capacity (TAC) of plasma was significantly lower in patients with fibromyalgia (n = 20) than in healthy controls (n = 20) [1.5 (SD 0.3) and 1.9 (SD 0.3) mmol Trolox equiv./l, P = 0.001]. In contrast, the total peroxide level of plasma was significantly higher in patients than in healthy controls [37.4 (SD 6.7) and 33.0 (SD 2.7) micromol H2O2/l; P = 0.01]. The oxidative stress index (OSI) level was significantly higher in patients with fibromyalgia than in healthy controls [2.5 (SD 1.0) and 1.8 (SD 0.4); P = 0.007]. A significant negative correlation between visual analogue scale (VAS) and TAC level was determined (r = -0.79, P < 0.001). The present results indicate that patients with fibromyalgia are exposed to oxidative stress and this increased oxidative stress may play a role in the etiopathogenesis of the disease. Supplementation of antioxidant vitamins such as vitamins C and E to the therapy may be indicated.

Paraoxonase, anti-oxidant response and oxidative stress in children with chronic renal failure

Increased oxidative stress is believed to contribute to an increased risk of cardiovascular disease in uraemia. In children with chronic renal failure (CRF), an anti-oxidant enzyme, paraoxonase (PON), that inhibits oxidation of LDL-cholesterol, has not been previously investigated. In this study we aimed to investigate PON activity, total anti-oxidant response (TAR), total peroxide (TPX), oxidative stress index (OSI) and some pro-oxidant cytokines in 29 children with CRF [mean age 10.2+/-3.5 years; 19 pre-dialysis, ten on continuous ambulatory peritoneal dialysis (CAPD)] and in 25 control subjects. Children with CRF had lower PON and TAR and higher TPX and OSI values than did controls (P<0.05). Except for lower TAR and serum albumin levels of the CAPD subgroup (P<0.05), other parameters were similar in non-dialysis and CAPD patients (P>0.05). Patients had significant positive correlation between TAR and serum albumin (P<0.05). Serum urea had significant positive correlation with TPX and OSI (P<0.05). Increased oxidative stress and decreased anti-oxidants measured by serum PON activity and TAR were found in children with CRF. We can hypothesize, on the basis of statistical correlations, that low levels of serum albumin and high levels of uraemic metabolites might be responsible for increased oxidative stress in children with CRF. Further studies with larger sample sizes are needed to verify these results.

Increased oxidative stress in infants exposed to passive smoking

The purpose of this study was to assess the effect of passive cigarette smoking on the oxidative and anti-oxidative status of plasma in infants. Eighty-four infants aged 6-28 weeks were divided into two groups: the study group included infants who had been exposed to passive smoking via at least five cigarettes per day for at least the past 6 weeks at home, while the control group included infants who had never been exposed to passive smoking. The antioxidative status of plasma was assessed by the measurement of individual antioxidant components: vitamin C, albumin, bilirubin, uric acid, thiol contents and total antioxidant capacity (TAC 1 and TAC 2). Oxidative status was assessed by the determination of total peroxide levels and the oxidative stress index (OSI 1 and OSI 2). Plasma vitamin C, thiol concentration and TAC 1 and TAC 2 levels were significantly lower, whereas plasma total peroxide levels and OSI 1 and OSI 2 were significantly higher, in passive smoking infants than in the controls (P<0.01). We conclude that passive smoking has a negative impact on numerous parts of the antioxidant defence system in infants, and exposes them to potent oxidative stress.

A new automated colorimetric method for measuring total oxidant status

OBJECTIVES

To develop a new, colorimetric and automated method for measuring total oxidation status (TOS).

DESIGN AND METHODS

The assay is based on the oxidation of ferrous ion to ferric ion in the presence of various oxidant species in acidic medium and the measurement of the ferric ion by xylenol orange. The oxidation reaction of the assay was enhanced and precipitation of proteins was prevented. In addition, autoxidation of ferrous ion present in the reagent was prevented during storage. The method was applied to an automated analyzer, which was calibrated with hydrogen peroxide and the analytical performance characteristics of the assay were determined.

RESULTS

There were important correlations with hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide solutions (r=0.99, P<0.001 for all). In addition, the new assay presented a typical sigmoidal reaction pattern in copper-induced lipoprotein autoxidation. The novel assay is linear up to 200 micromol H2O2 Equiv./L and its precision value is lower than 3%. The lower detection limit is 1.13 micromol H2O2 Equiv./L. The reagents are stable for at least 6 months on the automated analyzer. Serum TOS level was significantly higher in patients with osteoarthritis (21.23+/-3.11 micromol H2O2 Equiv./L) than in healthy subjects (14.19+/-3.16 micromol H2O2 Equiv./L, P<0.001) and the results showed a significant negative correlation with total antioxidant capacity (TAC) (r=-0.66 P<0.01).

CONCLUSIONS

This easy, stable, reliable, sensitive, inexpensive and fully automated method that is described can be used to measure total oxidant status.