Method for the simultaneous determination of free/protein malondialdehyde and lipid/protein hydroperoxides

Time-Related Evidence of Intestinal Oxidative Stress in Obstructive Jaundice-Induced Rats

INTRODUCTION

Obstructive jaundice is known to affect intestinal permeability and facilitate bacterial translocation through related mechanisms. This study was conducted to evaluate the alterations concerning blood biochemistry and levels of several markers of oxidative stress (OS) in blood and intestinal mucosa caused by obstructive jaundice and how these fluctuate over time, in order to further explore the possibility of intervening in the OS path in future experiments.

METHODS

A total of 54 albino Wistar rats were randomly divided into three groups (control, sham operated, and bile duct ligation) and sacrificed at specific time intervals (12 h and 2, 7, and 14 days). The intestinal barrier function was evaluated by measuring endotoxin levels in portal, aortic, and peripheral blood. Also, basic biochemical parameters were simultaneously measured in peripheral blood. Tissue samples collected from the terminal ileum were homogenized for determining the OS markers, lipid peroxidation, and protein-free radical-induced oxidation.

RESULTS

We designed this experiment to examine the alterations in enteric mucosa primarily in relation to OS in a period of 14 days. During this time period, we investigated in specific time intervals not only OS fluctuations but also other liver function parameters, as well as CRP and endotoxin levels. The alterations were monitored in relation to time after bile duct ligation.

CONCLUSION

Bile duct ligation in rats causes OS versus post-ligation time progression of the common bile duct. OS was increased by ∼50% compared to control/sham and peaked at 7 days and at least up to 14 days post-ligation. This phenomenon was accompanied with a deranging of liver function after ligation, as anticipated, but not in all measured parameters; biochemical and endotoxin levels followed the same pattern.

Methods on LDL particle isolation, characterization, and component fractionation for the development of novel specific oxidized LDL status markers for atherosclerotic disease risk assessment

The present study uses simple, innovative methods to isolate, characterize and fractionate LDL in its main components for the study of specific oxidations on them that characterize oxidized low-density lipoprotein (oxLDL) status, as it causatively relates to atherosclerosis-associated cardiovascular disease (CVD) risk assessment. These methods are: (a) A simple, relatively time-short, low cost protocol for LDL isolation, to avoid shortcomings of the currently employed ultracentrifugation and affinity chromatography methodologies. (b) LDL purity verification by apoB100 SDS-PAGE analysis and by LDL particle size determination; the latter and its serum concentration are determined in the present study by a simple method more clinically feasible as marker of CVD risk assessment than nuclear magnetic resonance. (c) A protocol for LDL fractionation, for the first time, into its main protein/lipid components (apoB100, phospholipids, triglycerides, free cholesterol, and cholesteryl esters), as well as into LDL carotenoid/tocopherol content. (d) Protocols for the measurement, for the first time, of indicative specific LDL component oxidative modifications (cholesteryl ester-OOH, triglyceride-OOH, free cholesterol-OOH, phospholipid-OOH, apoB100-MDA, and apoB100-DiTyr) out of the many (known/unknown/under development) that collectively define oxLDL status, which contrasts with the current non-specific oxLDL status evaluation methods. The indicative oxLDL status markers, selected in the present study on the basis of expressing early oxidative stress-induced oxidative effects on LDL, are studied for the first time on patients with end stage kidney disease on maintenance hemodialysis, selected as an indicative model for atherosclerosis associated diseases. Isolating LDL and fractionating its protein and main lipid components, as well as its antioxidant arsenal comprised of carotenoids and tocopherols, paves the way for future studies to investigate all possible oxidative modifications responsible for turning LDL to oxLDL in association to their possible escaping from LDL's internal antioxidant defense. This can lead to studies to identify those oxidative modifications of oxLDL (after their artificial generation on LDL), which are recognized by macrophages and convert them to foam cells, known to be responsible for the formation of atherosclerotic plaques that lead to the various CVDs.

Time progression and regional expression of brain oxidative stress induced by obstructive jaundice in rats

BACKGROUND

Obstructive jaundice induces oxidative changes in the brain parenchyma and plays significant role in clinical manifestations of hepatic encephalopathy. We aim to study the progression of the brain oxidative status over time and the differences of its pattern over the hemispheres, the brainstem and the cerebellum. We use an experimental model in rats and measuring the oxidative stress (OS) specific biomarkers protein malondialdehyde (PrMDA) and protein carbonyls (PrC = O).

RESULTS

Hyperbilirubinemia has been confirmed in all study groups as the result of common bile duct obstruction. We confirmed increase in both PrMDA and PrC = O biomarkers levels with different type of changes over time. We also confirmed that the oxidative process develops differently in each of the brain areas in study.

CONCLUSIONS

The present study confirms the progressive increase in OS in all brain areas studied using markers indicative of cumulative protein modification.

Maternal Calorie Restriction Induces a Transcriptional Cytoprotective Response in Embryonic Liver Partially Dependent on Nrf2

BACKGROUND

Calorie restriction is known to enhance Nrf2 signaling and longevity in adult mice, partially by reducing reactive oxygen species, but calorie restriction during pregnancy leads to intrauterine growth retardation. The latter is associated with fetal reprogramming leading to increased incidence of obesity, metabolic syndrome and diabetes in adult life. Transcription factor Nrf2 is a central regulator of the antioxidant response and its crosstalk with metabolic pathways is emerging. We hypothesized that the Nrf2 pathway is induced in embryos during calorie restriction in pregnant mothers.

METHODS

From gestational day 10 up to day 16, 50% of the necessary mouse diet was provided to Nrf2 heterozygous pregnant females with fathers being of the same genotype. Embryos were harvested at the end of gestational day 16 and fetal liver was used for qRT-PCR and assessment of oxidative stress (OS).

RESULTS

Intrauterine calorie restriction led to upregulation of mRNA expression of antioxidant genes (Nqo1, Gsta1, Gsta4) and of genes related to integrated stress response (Chac1, Ddit3) in WT embryos. The expression of a key gluconeogenic (G6pase) and two lipogenic genes (Acacb, Fasn) was repressed in calorie-restricted embryos. In Nrf2 knockout embryos, the induction of Nqo1 and Gsta1 genes was abrogated while that of Gsta4 was preserved, indicating an at least partially Nrf2-dependent induction of antioxidant genes after in utero calorie restriction. Measures of OS showed no difference (superoxide radical and malondialdehyde) or a small decrease (thiobarbituric reactive substances) in calorie-restricted WT embryos.

CONCLUSIONS

Calorie restriction during pregnancy elicits the transcriptional induction of cytoprotective/antioxidant genes in the fetal liver, which is at least partially Nrf2-dependent, with a physiological significance that warrants further investigation.

Redox Status Response of Physical Exercise Training in Women with Breast Cancer during Trastuzumab Therapy

Trastuzumab is indicated in the adjuvant setting for the early and intermediate stages of breast cancer (BC) positive for epidermal growth factor receptor 2 (HER2). Although HER2 in BC patients tends to disrupt pro-oxidant and inflammatory signaling, the influence of trastuzumab in modulating this process remains unknown. Due to the absence of any chemotherapeutic or chemoprophylactic agents for trastuzumab-induced side effects, this study investigated the potential role of regular physical exercise in modulating the antioxidant defenses, oxidative stress, and nitrosative damage in BC patients during trastuzumab treatment.

AIM

The study aimed to analyze the relationship between regular physical activity and the redox status in women with BC during trastuzumab therapy.

MATERIALS AND METHODS

We observed 50 BC patients during trastuzumab therapy in two groups: one that undertook moderately intensive supervised physical exercises, and a second that performed physical activity according to the recommendations for cancer patients, along with a third (control) group of healthy women.

RESULTS

The antioxidant enzyme and non-enzymatic antioxidant activities were significantly higher in the exercised group compared with the other participants. The concentrations of lipid and protein oxidative damage and nitrosative stress products were significantly higher in both BC groups than in the healthy controls.

CONCLUSIONS

Trastuzumab treatment stimulates a redox response in BC patients. The results highlight the oxidative imbalance in parallel with regular physical training in women with BC during trastuzumab therapy. Further studies are needed to analyze different intensities and levels of physical training in women with BC during trastuzumab treatment.

Predictive value of oxidative stress biomarkers in drug-free patients with bipolar disorder

OBJECTIVE

Oxidative stress is one of the primary etiological mechanisms of bipolar disorder (BD).

METHODS

The present study was conducted over a period of 24 months on Tunisian on 34 drug‑free male patients with BD (mean age: 34.5 years) and 101 age and gender matched controls (mean age: 34.20 years) were enrolled in the study.

RESULTS

Plasma reduced glutathione (GSH) and total thiols levels were significantly decreased in patients compared to controls (respectively p < .001; p = .009). In addition, malondialdehyde (MDA), advanced oxidation protein products (AOPP), protein carbonyls (PC) and homocysteine (Hcys) concentrations and glutathione peroxidase (GSH-Px) activity were significantly increased in patients compared to controls (p = .002; p < .001; p = .001; p < .001 and p = .016, respectively). The binary logistic regression analysis revealed that MDA, AOPP and Hcys could be considered as independent risk factors for BD. When using CombiROC analysis, a remarkable increase in the area under the curve (AUC) with higher sensitivity (Se) and specificity (Sp) for MDA, AOPP, PC, GSH-Px and Hcys combined markers was observed.

CONCLUSIONS

Overall, the identification of the predictive value of these five selected biomarkers related to oxidative stress in drug free patients should lead to a better identification of the etiological mechanism of BD.

Exploration of anti-chromium mechanism of marine Penicillium janthinellum P1 through combinatorial transcriptomic analysis and WGCNA

Fungi have a promising application prospect in the remediation of heavy-metal wastewater pollution which is a sticky global problem. New marine-derived strain Penicillium janthinellum P1 is of high chromium resistance. However, a comprehensive study of the transcriptomics in Penicillium janthinellum P1 strains is lacking. Firstly, the changing trends of a series of physiological and biochemical indices of P1 strain at 0 M and 1 M Cr concentration were investigated to track the ROS variation. Secondly, transcriptome sequencing of P1 was performed by RNA-Seq sequencing technology. The transcriptome data indicated that 12,352 coding protein regions were predicted, and 6655 differentially expressed genes were identified by DESeq2, of which 4234 genes were up-regulated, and 2421 genes down-regulated. Through further co-expression network of WGCNA analysis, the filtered unigenes were clustered into 19 modules. Combined with the physiological and biochemical findings, the three modules with the highest correlation with the six traits were selected to construct the network, and 52 hub genes were obtained. Furthermore, 10 speculative hub genes related to chromium resistance were selected and verified by real-time PCR. The results were in line with the expected experimental assumption. These results improve our understanding of the transcriptomic dimensions of the high chromium resistance of Penicillium janthinellum P1 strains.

Therapeutic Interventions to Mitigate Mitochondrial Dysfunction and Oxidative Stress–Induced Damage in Patients with Bipolar Disorder

Bipolar disorder (BD) is characterized by mood changes, including recurrent manic, hypomanic, and depressive episodes, which may involve mixed symptoms. Despite the progress in neurobiological research, the pathophysiology of BD has not been extensively described to date. Progress in the understanding of the neurobiology driving BD could help facilitate the discovery of therapeutic targets and biomarkers for its early detection. Oxidative stress (OS), which damages biomolecules and causes mitochondrial and dopamine system dysfunctions, is a persistent finding in patients with BD. Inflammation and immune dysfunction might also play a role in BD pathophysiology. Specific nutrient supplements (nutraceuticals) may target neurobiological pathways suggested to be perturbed in BD, such as inflammation, mitochondrial dysfunction, and OS. Consequently, nutraceuticals may be used in the adjunctive treatment of BD. This paper summarizes the possible roles of OS, mitochondrial dysfunction, and immune system dysregulation in the onset of BD. It then discusses OS-mitigating strategies that may serve as therapeutic interventions for BD. It also analyzes the relationship between diet and BD as well as the use of nutritional interventions in the treatment of BD. In addition, it addresses the use of lithium therapy; novel antipsychotic agents, including clozapine, olanzapine, risperidone, cariprazine, and quetiapine; and anti-inflammatory agents to treat BD. Furthermore, it reviews the efficacy of the most used therapies for BD, such as cognitive–behavioral therapy, bright light therapy, imagery-focused cognitive therapy, and electroconvulsive therapy. A better understanding of the roles of OS, mitochondrial dysfunction, and inflammation in the pathogenesis of bipolar disorder, along with a stronger elucidation of the therapeutic functions of antioxidants, antipsychotics, anti-inflammatory agents, lithium therapy, and light therapies, may lead to improved strategies for the treatment and prevention of bipolar disorder.

Oxidized lipid-associated protein damage in children and adolescents with type 1 diabetes mellitus: New diagnostic/prognostic clinical markers

BACKGROUND

Type 1 diabetes mellitus (DM1), a chronic metabolic disorder of autoimmune origin, has been associated with oxidative stress (OS), which plays a central role in the onset, progression, and long-term complications of DM1. The markers of OS lipid peroxidation products, lipid hydroperoxides (LOOH), and also malondialdehyde (MDA) and thiobarbituric reactive substances (TBARS) that oxidatively modify proteins (Pr) (i.e., PrMDA and PrTBARS, respectively), have been associated with DM2, DM1, diabetic neuropathy, and microalbuminuria.

OBJECTIVE/SUBJECTS

Here, we investigated LOOH, PrMDA and PrTBARS in 50 children and adolescents with DM1 and 21 controls.

RESULTS

The novel OS marker PrTBARS was assessed for the first time in children and adolescents with DM1. LOOH and the pair PrMDA/PrTBARS, representing early and late peroxidation stages, respectively, are found to be significantly higher (130%, 50/90%, respectively, at p < 0.001) in patients with DM1 compared to controls. The studied OS parameters did not differ with age, age at diagnosis, sex, duration of DM1, presence of recent ketosis/ketoacidosis, or mode of treatment.

CONCLUSIONS

We propose that LOOH, PrMDA and the new marker PrTBARS could serve as potential diagnostic clinical markers for identifying OS in children and adolescents with DM1, and may, perhaps, hold promise as a prognostic tool for future complications associated with the disease.

Effects of Panthenol and N-Acetylcysteine on Changes in the Redox State of Brain Mitochondria under Oxidative Stress In Vitro

The glutathione system in the mitochondria of the brain plays an important role in maintaining the redox balance and thiol–disulfide homeostasis, whose violations are the important component of the biochemical shifts in neurodegenerative diseases. Mitochondrial dysfunction is known to be accompanied by the activation of free radical processes, changes in energy metabolism, and is involved in the induction of apoptotic signals. The formation of disulfide bonds is a leading factor in the folding and maintenance of the three-dimensional conformation of many specific proteins that selectively accumulate in brain structures during neurodegenerative pathology. In this study, we estimated brain mitochondria redox status and functioning during induction of oxidative damage in vitro. We have shown that the development of oxidative stress in vitro is accompanied by inhibition of energy metabolism in the brain mitochondria, a shift in the redox potential of the glutathione system to the oxidized side, and activation of S-glutathionylation of proteins. Moreover, we studied the effects of pantothenic acid derivatives—precursors of coenzyme A (CoA), primarily D-panthenol, that exhibit high neuroprotective activity in experimental models of neurodegeneration. Panthenol contributes to the significant restoration of the activity of enzymes of mitochondrial energy metabolism, normalization of the redox potential of the glutathione system, and a decrease in the level of S-glutathionylated proteins in brain mitochondria. The addition of succinate and glutathione precursor N-acetylcysteine enhances the protective effects of the drug.

Daytime Evaluation of Oxidative Stress and Behavioural Parameters of Donkeys (Equus asinus) During The Hot-Dry and Cold-Dry (Harmattan) Season in a Tropical Savannah

The aim of the study was to evaluate oxidative stress and behavioural responses of donkeys during the cold-dry and hot-dry seasons. Thirty donkeys divided into three groups of ten donkeys each according to their age served as experimental subjects. During each season, behavioural and blood parameters of the donkeys were evaluated three times with an interval of one week at 06:00 h, 12:00 h and 18:00 h (GMT+1). During the hot-dry season, the peak dry-bulb temperature (DBT) value of 36.00 ± 1.00°C was recorded at 12:00 h, indicating that the season induced heat stress. The time spent feeding demonstrated diurnal fluctuations in adult, yearling and foal donkeys, with the highest time occurring at 12:00 h in both seasons. The malondialdehyde (MDA) concentrations in adults (2.34 ± 0.14 nMol/L), yearlings (2.28 ± 0.19 nMol/L) and foals (3.48 ± 0.17 nMol/L) during the hot-dry season were significantly (P < 0.05) higher, when compared to the corresponding values (0.96 ± 0.09, 1.18 ± 0.10 and 1.82 ± 0.10 nMol/L, respectively) recorded during the cold-dry season. At 0.3% NaCl-concentration, the percentage haemolysis obtained during the hot-dry season in adult (90.33 ± 0.49%), yearling (91.24 ± 0.88%) and foal (97.44 ± 0.24%) donkeys were significantly (P < 0.05) higher than the corresponding values (78.53 ± 0.98, 78.67 ± 0.58 and 88.23 ± 0.47%, respectively), recorded during the cold-dry season. In conclusion, the hot-dry season induced heat stress in the donkeys, resulting in a decrease in time spent on feeding and oxidative stress, as evidenced by high erythrocyte MDA concentration and percentage haemolysis.

Sperm DNA damage and seminal antioxidant activity in subfertile men

Supraphysiological ROS levels can lead to apoptosis, lipid peroxidation, and DNA and protein damage. This pilot study aimed to investigate the sperm oxidative damage in subfertile men, to describe the relationship between the antioxidant system and ROS. Sixty-four semen samples were categorised according to the evaluated routine parameters (WHO, WHO laboratory manual for the examination and processing of human semen, 2010). Results were cross-referenced with the DNA damage [Comet (n = 53) and TUNEL (n = 49) assays], antioxidant enzyme activity [SOD (n = 51), CAT (n = 48) and GST (n = 48)], and content of total thiols (n = 36), lipid hydroperoxides (n = 35) and MDA (n = 31). Compared to pathospermic samples, normozoospermic presented 40%-45% fewer spermatozoa with fragmented DNA, 19% fewer hydroperoxides, and slightly higher total thiols and MDA levels. Asthenozoospermic/asthenoteratozoospermic samples had the lowest GST activity. SOD and CAT showed a similar trend. Our results evidenced significant positive correlations between DNA damage and immotile spermatozoa; SOD and CAT, GST and total thiols; CAT and GST; total thiols and sperm concentration; and MDA levels and head/midpiece abnormalities and hydroperoxides. This work contributes to the existing body of knowledge by showing that the oxidative status correlates with the classic sperm analysis parameters. Oxidative stress and DNA damage evaluation might be a valuable diagnostic and prognostic tool in cases of idiopathic male subfertility.

Phloroglucinol Strengthens the Antioxidant Barrier and Reduces Oxidative/Nitrosative Stress in Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is one of the most commonly occurring diseases within western dietary patterns. Usually untreated, it may lead to type 2 diabetes mellitus (T2DM), steatohepatitis (NASH), and hepatocellular carcinoma (HCC). Besides its severe aftermath, up to now, there is no known therapeutic approach to this disease in everyday clinical practice. Most NAFLD patients are encouraged to do physical activities or diet change and remain without pharmacological treatment. In this study, we present phloroglucinol (PHG) as a novel and promising compound in NAFLD treatment. PHG significantly increased the level of enzymatic and nonenzymatic antioxidants both in palmitate and hydrogen peroxide-induced oxidative stress models. Strengthened antioxidative defense reduced the oxidative/nitrosative damage to cell proteins, lipids, and carbohydrates. Furthermore, PHG treatment reduced hepatic steatosis; lowered inflammatory markers, such as NF-κB or HIF-1α; and inhibited cell apoptosis. Moreover, PHG had a more comprehensive effect than other commonly used antioxidants: N-acetylcysteine (NAC) and α-lipoic acid (ALA), suggesting its clinical usability. Therefore, our paper supports the benefits of natural compounds as a therapeutical approach to NAFLD.

Formation of α-tocopherol hydroperoxide and α-tocopheroxyl radical: relevance for photooxidative stress in Arabidopsis

Tocopherols, lipid-soluble antioxidants play a crucial role in the antioxidant defense system in higher plants. The antioxidant function of α-tocopherol has been widely studied; however, experimental data on the formation of its oxidation products is missing. In this study, we attempt to provide spectroscopic evidence on the detection of oxidation products of α-tocopherol formed by its interaction with singlet oxygen and lipid peroxyl radical. Singlet oxygen was formed using photosensitizer rose bengal and thylakoid membranes isolated from Arabidopsis thaliana. Singlet oxygen reacts with polyunsaturated fatty acid forming lipid hydroperoxide which is oxidized by ferric iron to lipid peroxyl radical. The addition of singlet oxygen to double bond carbon on the chromanol head of α-tocopherol forms α-tocopherol hydroperoxide detected using fluorescent probe swallow-tailed perylene derivative. The decomposition of α-tocopherol hydroperoxide forms α-tocopherol quinone. The hydrogen abstraction from α-tocopherol by lipid peroxyl radical forms α-tocopheroxyl radical detected by electron paramagnetic resonance. Quantification of lipid and protein hydroperoxide from the wild type and tocopherol deficient (vte1) mutant Arabidopsis leaves using a colorimetric ferrous oxidation-xylenol orange assay reveals that α-tocopherol prevents formation of both lipid and protein hydroperoxides at high light. Identification of oxidation products of α-tocopherol might contribute to a better understanding of the protective role of α-tocopherol in the prevention of oxidative damage in higher plants at high light.

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.

Comprehensive Evaluation of the Oral Health Status, Salivary Gland Function, and Oxidative Stress in the Saliva of Patients with Subacute Phase of Stroke: A Case-Control Study

This is the first study to assess, comprehensively, the oral health status; salivary glands’ function and enzymatic and non-enzymatic antioxidant defense; and oxidative damage to proteins and lipids in the non-stimulated (NWS) and stimulated (SWS) whole saliva of stroke patients. The study included 30 patients in the subacute phase of the stroke and an age and gender-matched control group. We showed that the activity of antioxidant enzymes (catalase and salivary peroxidase) was significantly higher in both NWS and SWS of stroke patients, similarly to uric acid concentration. However, in the study group, the reduced glutathione (GSH) concentration in SWS decreased. The contents of protein glycooxidation products (advanced glycation end products (AGE) and protein oxidation products (AOPP)) and lipid hydroperoxides were significantly higher in NWS and SWS of stroke patients. In the study group there was also a decrease in stimulated saliva secretion and total protein content. Interestingly, products of protein and lipid oxidation correlate negatively with SWS flow. The ROC analysis showed that salivary GSH with 100% specificity and 100% sensitivity differentiates the analyzed groups (AUC = 1.0). To sum up, in subacute stroke patients there are redox imbalances and oxidative damage to proteins and lipids in non-stimulated and stimulated saliva. Stroke patients also suffer from salivary gland dysfunction.

Enhanced Salivary and General Oxidative Stress in Hashimoto's Thyroiditis Women in Euthyreosis

Hashimoto’s thyroiditis (HT) is one of the most common autoimmune diseases. Although HT is inextricably linked to oxidative stress, there have been no studies assessing salivary redox homeostasis or salivary gland function in patients with HT. This study is the first to compare antioxidant defense and oxidative stress biomarkers in non-stimulated (NWS) and stimulated (SWS) whole saliva and plasma/erythrocytes of HT patients compared to controls. The study included 45 women with HT in the euthyreosis period as well as an age- and gender-matched control group. We showed that NWS secretion was significantly lower in HT patients compared to healthy controls, similar to salivary amylase activity in NWS and SWS. Catalase and peroxidase activities were considerably higher in NWS and SWS of HT patients, while the concentrations of reduced glutathione and uric acid were significantly lower in comparison with healthy subjects. Total antioxidant potential was significantly lower, while total oxidant status and the level of oxidation products of proteins (advanced glycation end products, advanced oxidation protein products) and lipids (malondialdehyde, lipid hydroperoxides) were significantly higher in NWS, SWS and plasma of HT patients. In conclusion, in both salivary glands of women with HT in euthyreosis, the ability to maintain redox homeostasis was hindered. In HT patients we observed oxidative damage to salivary proteins and lipids; thus, some biomarkers of oxidative stress may present a potential diagnostic value.

Role of 904 nm superpulsed laser-mediated photobiomodulation on nitroxidative stress and redox homeostasis in burn wound healing

BACKGROUND

Burn wound healing is delayed due to several critical factors such as sustained inflammation, vascular disorder, neuropathy, enhanced proteolysis, infection, and oxidative stress. Burn wounds have limited oxygen supply owing to compromised blood circulation. Hypoxic burn milieu leads to free radicals overproduction incurring oxidative injury, which impedes repair process causing damage to cell membranes, proteins, lipids, and DNA. Photobiomodulation (PBM) with 904 nm superpulsed laser had shown potent healing efficacy via attenuating inflammation while enhancing proliferation, angiogenesis, collagen accumulation, and bioenergetic activation in burn wounds.

METHODS

This study investigated the effects of 904 nm superpulsed laser at 0.4 mW/cm² average power density, 0.2 J/cm² total energy density, 100 Hz frequency, and 200 ns pulse width for 10 min daily for seven days postburn injury on nitroxidative stress, endogenous antioxidants status, and redox homeostasis.

RESULTS

Photobiomodulation treatment significantly decreased reactive oxygen species, nitric oxide, and lipid peroxidation levels as compared to non-irradiated control. Further, protective action of PBM against protein oxidative damage was evidenced by reduced protein carbonylation and advanced oxidation protein product levels along with significantly enhanced endogenous antioxidants levels of SOD, catalase, GPx, GST, reduced glutathione, and thiol (T-SH, Np-SH, P-SH). Biochemical changes aid in reduction of oxidative stress and maintenance of redox homeostasis, which further well corroborated by significantly up-regulated protein expression of Nrf 2, hemeoxygenase (HO-1), and thioredoxin reductase 2 (Txnrd2).

CONCLUSION

Photobiomodulation with 904 nm superpulsed laser led to reduction of nitroxidative stress, induction of endogenous antioxidants, and maintenance of redox homeostasis that could play a vital role in augmentation of burn wound healing.

Effects of Vitamin C on the Prevention of Ischemia-Reperfusion Brain Injury: Experimental Study in Rats

Background

Reperfusion syndrome after carotid endarterectomy is a complication associated with cerebrovascular self-regulation in a chronically hypoperfused cerebral hemisphere, leading to severe neurological damage. Vitamin C is an important antioxidant in brain metabolism that has shown some neuroprotective actions.

Objective

To investigate the potential effects of vitamin C on cerebral reperfusion in comparison with placebo (saline) in rats.

Methods

Male Wistar rats were divided into 3 groups: (i) Sham (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (

Results

Rats treated with vitamin C presented with a similar behavior as compared to the Sham group in all the three tests (p > 0.05), but it was significantly different from controls (p > 0.05), but it was significantly different from controls (p > 0.05), but it was significantly different from controls (

Conclusion

In the present study, vitamin C was associated with behavioral and motor preservation as well as decreased cerebral MDA levels after induced cerebral ischemia in rats.

Ageing differently: Sex-dependent ageing rates in Daphnia magna

Ageing is defined as the gradual decline of normal physiological functions in a time-dependent manner. Significant progress has been made in characterising the regulatory processes involved in the mechanisms of ageing which would have been hindered without the use of model organisms. Use of alternative model organisms greatly diversifies our understanding of different factors underpinning the ageing process and the potential translation for human application. Unique characteristics make Daphnia an attractive model organism for research into mechanisms underlying ageing, such as transparent body, short generation time, well-characterised methylome, regenerative capabilities and available naturally occurring ecotypes. Most interestingly, genetically identical female and male Daphnia have evolved different average lifespans, providing a unique opportunity for understanding the underlying mechanisms of ageing and regulation of lifespan. Investigating sex differences in longevity could provide insight into principal mechanisms of ageing and lifespan regulation. In this study we provide evidence in support of establishing genetically identical female and male Daphnia as unique and valuable resources for research into mechanisms of ageing and begin to delineate the mechanisms involved in sex differences in lifespan. We identify significant differences between genders in physiological markers such as lifespan, growth rate, heart rate and swimming speed in addition to molecular markers such as lipid peroxidation product accumulation, thiol content decline and age-dependent decline in DNA damage repair efficiency. Overall, our data indicates that investigating sex differences in longevity in the clonal organism Daphnia under controlled laboratory conditions can provide insight into principal mechanisms of ageing and lifespan regulation.

NaCl stress on physio-biochemical metabolism and antioxidant capacity in germinated hulless barley (Hordeum vulgare L.)

BACKGROUND

Hulless barley generally grows in barren fields, where soil salinization is serious. However, only a few studies have been carried out investigating germinated hulless barley under salt stress. In the present study, the effect of NaCl stress on the physio-biochemical metabolism and antioxidant capacity of germinated hulless barley was investigated.

RESULTS

NaCl stress inhibited seedling growth and caused oxidative damage, although it enhanced the accumulation of phenolic compounds and antioxidant capacity. The highest contents of total phenolic and main phenolic acids (vanillic acid, p-coumaric acid, ferulic acid and sinapic acid) were found with 60 mmol L^-1 NaCl treatment, whereas 120 mmol L^-1 NaCl inhibited the synthesis of phenolic components. Gene expression of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate coenzyme A ligase (4CL), p-coumaric acid 3-hdroxylase (C3H) and caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT), which participated in the synthesis of phenolic compounds, was up-regulated by NaCl stress, as were the enzyme activities of PAL, C4H and 4CL. NaCl treatment also enhanced the antioxidant enzyme activities of germinated hulless barley.

CONCLUSION

NaCl stress inhibited seedlings growth and caused oxidative damage. Simultaneously, the antioxidant system of germinated hulless barley was enhanced. The results of the present study provide a theoretical basis with respect to the growth of hulless barley under salt stress. © 2018 Society of Chemical Industry.

Protein carbonyl determination by a rhodamine B hydrazide-based fluorometric assay

A new fluorometric assay is presented for the ultrasensitive quantification of total protein carbonyls, and is based on their specific reaction with rhodamine B hydrazide (RBH), and the production of a protein carbonyl-RBH hydrazone the fluorescence of which (at ex/em 560/585 nm) is greatly enhanced by guanidine-HCl. Compared to the fluorescein-5-thiosemicarbazide (FTC)-based fluorometric assay, the RBH assay uses a 24-fold shorter reaction incubation time (1 h) and at least 1000-fold lower protein quantity (2.5 µg), and produces very reliable data that were verified by extensive standardization experiments. The protein carbonyl group detection sensitivity limit of the RBH assay, based on its standard curve, can be as low as 0.4 pmol, and even lower. Counting the very low protein limit of the RBH assay, its cumulative and functional sensitivity is 8500- and 800-fold higher than the corresponding ones for the FTC assay. Neither heme proteins hemoglobin and cytochrome c nor DNA interfere with the RBH assay.

Propranolol reduces systemic oxidative stress and endotoxemia in cirrhotic patients with esophageal varices

BACKGROUND

The aim of the study was to investigate the effect of propranolol on systemic oxidative stress and endotoxemia in patients with liver cirrhosis and clinically significant portal hypertension evidenced by the presence of esophageal varices.

METHODS

Fourteen patients with liver cirrhosis and esophageal varices, not previously been treated with non-selective beta-blockers (NSBB), were prospectively started on propranolol and followed up for three months. Serum early and late lipid peroxidation products (lipid hydroperoxides [LOOH] and malondialdehyde [MDA], respectively), and endotoxin concentrations in peripheral blood were measured. Fourteen age- and sex-matched healthy individuals were used as controls.

RESULTS

Patients with liver cirrhosis presented significantly higher systemic oxidative stress and endotoxin concentrations compared to healthy controls (P<0.001). Propranolol treatment for one month significantly reduced serum MDA (P<0.05), LOOH (P<0.01), and endotoxin levels (P<0.01) compared to pre-treatment values, whilst LOOH reached control levels. At three months of propranolol treatment, serum LOOH did not differ significantly from the one-month values, whilst serum endotoxin and MDA levels were further reduced between 3- and 1-month period (P<0.05 and P<0.01, respectively), with the latter reaching control levels. Amelioration of systemic endotoxemia at the one- and three-month follow-up intervals (compared to pre-treatment values) was not correlated with the respective reductions in serum MDA and LOOH.

CONCLUSIONS

This is the first study to show that NSBB treatment in liver cirrhosis exerts a significant systemic antioxidant action. This effect seems to be, at least partly, independent of their beneficial effects on intestinal barrier function and endotoxemia.

Detection and scavenging of hydroxyl radical via D-phenylalanine hydroxylation in human fluids

Hydroxyl radical (.OH) is highly reactive, and therefore very short-lived. Finding new means to accurately detect .OH, and testing the ability of known .OH scavengers to neutralize them in human biological fluids would leverage our ability to more effectively counter oxidative (.OH) stress-mediated damage in human diseases. To achieve this, we pursued the evaluation of secondary products resulting from .OH attack, using a detection system based on Fenton reaction-mediated D-phenylalanine (D-Phe) hydroxylation. This reaction in turn generates o-tyrosine (o-tyr), m-tyrosine (m-tyr) and p-tyrosine (p-tyr). Here, these isomers were separated by HPLC, equipped with fluorescence detectors due to the natural fluorescence of these hydrotyrosines. By extension, we found that, adding radical scavengers competed with D-Phe on .OH attack, thus allowing to determine the .OH quenching capacity of a given compound expressed as inhibition ratio percent (IR%). Using a kinetic approach, we then tested the .OH scavenging capacity (OHSC) of well-known antioxidant molecules. In a test tube, N,N'-dimethylthiourea (DMTU) was the most efficient scavenger as compared to Trolox and N-Acethyl-L-cysteine, with NAC being the less effective. OHSC assay was then applied to biological fluid samples as seminal plasma, human serum from normal subjects and patients undergoing hemodialysis (HD), colostrum and human breast milk from mothers that received daily doses of 30g of chocolate (70% cocoa) during pregnancy. We found that a daily administration of dark chocolate during pregnancy almost doubled OHSC levels in breast milk (1.88 ± 0.12 times, p < 0.01). Furthermore, HD treatment determined a significant reduction of serum OHSC concentration (54.63 ± 2.82%, p < 0.001). Our results provide evidence that Fenton reaction-mediated D-Phe hydroxylation is a suitable method for routine and non-invasive evaluation of .OH detection and its scavenging in human biological fluids.

Oxidative protein modification alters proteostasis under acute hypobaric hypoxia in skeletal muscles: a comprehensive in vivo study

While numerous maladies are associated with hypobaric hypoxia, muscle protein loss is an important under studied topic. Hence, the present study was designed to investigate the mechanism of muscle protein loss at HH. SD rats were divided into normoxic rats, while remaining rats were exposed to simulated hypoxia equivalent to 282-torr pressure (equal to an altitude of 7620 m, 8% oxygen), at 25 °C for 6, 12, and 24 h. Post-exposure rats were sacrificed and analysis was performed. Ergo, muscle loss-related changes were observed at 12 and 24 h post-HH exposure. An increased reactive oxygen species production and decreased thiol content was observed in HH-exposed rats. This disturbance caused substantial protein oxidative modification in the form of protein carbonyl content and advanced oxidation protein products. The analysis showed increase levels of bityrosine, oxidized tryptophan, lysine conjugate, lysine conjugate with MDA, protein hydroperoxide, and protein-MDA product. These changes were also in agreement with increase in lipid hydroperoxides and MDA content. HSP-70 and HSP-60 were upregulated significantly, and this finding is corroborated with increase in ER stress biomarker, GRP-78. Overloading of cells with misfolded proteins further activated degradative machinery. Consequently, pro-apoptotic signaling cascade, caspase-3, and C/EBP homologous protein were also activated in 24-h HH exposure. Release of tryptophan and tyrosine was also increased with 24-h HH exposure, indicated protein degradation. Elevation in resting intracellular calcium ion, [Ca2+]i, was also observed at 12- and 24-h HH exposure. The present study provides a detailed mechanistic representation of muscle protein loss during HH exposure.

BNN-20, a synthetic microneurotrophin, strongly protects dopaminergic neurons in the "weaver" mouse, a genetic model of dopamine-denervation, acting through the TrkB neurotrophin receptor

Neurotrophic factors are among the most promising treatments aiming at slowing or stopping and even reversing Parkinson's disease (PD). However, in most cases, they cannot readily cross the human blood-brain-barrier (BBB). Herein, we propose as a therapeutic for PD the small molecule 17-beta-spiro-[5-androsten-17,2'-oxiran]-3beta-ol (BNN-20), a synthetic analogue of DHEA, which crosses the BBB and is deprived of endocrine side-effects. Using the "weaver" mouse, a genetic model of PD, which exhibits progressive dopaminergic neurodegeneration in the Substantia Nigra (SN), we have shown that long-term administration (P1-P21) of BNN-20 almost fully protected the dopaminergic neurons and their terminals, via i) a strong anti-apoptotic effect, probably mediated through the Tropomyosin receptor kinase B (TrkB) neurotrophin receptor's PI3K-Akt-NF-κB signaling pathway, ii) by exerting an efficient antioxidant effect, iii) by inducing significant anti-inflammatory activity and iv) by restoring Brain-Derived Neurotrophic Factor (BDNF) levels. By intercrossing "weaver" with NGL mice (dual GFP/luciferase-NF-κΒ reporter mice, NF-κΒ.GFP.Luc), we obtained Weaver/NGL mice that express the NF-κB reporter in all somatic cells. Acute BNN-20 administration to Weaver/NGL mice induced a strong NF-κB-dependent transcriptional response in the brain as detected by bioluminescence imaging, which was abolished by co-administration of the TrkB inhibitor ANA-12. This indicates that BNN-20 exerts its beneficial action (at least in part) through the TrkB-PI3K-Akt-NF-κB signaling pathway. These results could be of clinical relevance, as they suggest BNN-20 as an important neuroprotective agent acting through the TrkB neurotrophin receptor pathway, mimicking the action of the endogenous neurotrophin BDNF. Thus BNN-20 could be proposed for treatment of PD.

Radiation-Driven Formation of Reactive Oxygen Species in Oxychlorine-Containing Mars Surface Analogues

The present study demonstrates that γ-radiolyzed perchlorate-containing Mars soil salt analogues (in a CO₂ atmosphere) generate upon H₂O wetting the reactive oxygen species (ROS) superoxide radical (O₂^•-), hydrogen peroxide (H₂O₂), and hydroxyl radicals (^•OH). This study also validates that analogue radiolysis forms oxychlorine species that, in turn, can UV-photolyze to ^•OH upon UV photolysis. This investigation was made possible by the development of a new assay for inorganic-origin O₂^•- and H₂O₂ determination and by the modification of a previous assay for soil ^•OH. Results show that radiolyzed Mg(ClO₄)₂ generates H₂O₂ and ^•OH; and when included as part of a mixture analogous to the salt composition of samples analyzed at the Mars Phoenix site, the analogue generated O₂^•-, H₂O₂, and ^•OH, with ^•OH levels 150-fold higher than in the radiolyzed Mg(ClO₄)₂ samples. Radiolyzed Mars Phoenix site salt analogue that did not contain Mg(ClO₄)₂ generated only ^•OH also at 150-fold higher concentration than Mg(ClO₄)₂ alone. Additionally, UV photolysis of the perchlorate γ radiolysis product chlorite (ClO₂^-) generated the oxychlorine products trihalide (Cl₃^-), chlorine dioxide (ClO₂^•), and hypochlorite (ClO^-), with the formation of ^•OH by UV photolysis of ClO^-. While the generation of ROS may have contributed in part to ¹⁴CO₂ production in the Viking Labeled Release (LR) experiment and O₂ (g) release in the Viking Gas Exchange (GEx) experiment, our results indicate that they are not likely to be the major contributor to the LR and GEx results. However, due to their highly reactive nature, they are expected to play a significant role in the alteration of organics on Mars. Additionally, experiments with hypochlorite show that the thermal stability of NaClO is in the range of the thermal stability observed for thermally liable oxidant responsible for the Viking LR results. Key Words: Mars-Oxygen-Salts-Radiation-Habitability. Astrobiology 17, 319-336.

Determination of Lipid Hydroperoxides in Marine Diatoms by the FOX2 Assay

Ecologically-relevant marine diatoms produce a plethora of bioactive oxylipins deriving from fatty acid oxidation, including aldehydes, hydroxy-fatty acids, epoxy-hydroxy-fatty acids, and oxo-acids. These secondary metabolites have been related to the negative effect of diatoms on copepod reproduction, causing low hatching success and teratogenesis in the offspring during periods of intense diatom blooms. The common intermediates in the formation of oxylipins are fatty acid hydroperoxides. The quantitative measurement of these intermediates can fundamentally contribute to understanding the function and role of lipoxygenase metabolites in diatom-copepod interactions. Here, we describe the successful adaptation of the ferrous oxidation-xylenol orange 2 (FOX2) assay to diatom samples, which showed several advantages over other spectrophotometric and polarographic methods tested in the present work. Using this method we assessed fatty acid hydroperoxide levels in three diatom species: Skeletonema marinoi, Thalassiosira rotula, and Chaetoceros affinis, and discuss results in light of the literature data on their detrimental effects on copepod reproduction.

Evidence for photochemical production of reactive oxygen species in desert soils

The combination of intense solar radiation and soil desiccation creates a short circuit in the biogeochemical carbon cycle, where soils release significant amounts of CO2 and reactive nitrogen oxides by abiotic oxidation. Here we show that desert soils accumulate metal superoxides and peroxides at higher levels than non-desert soils. We also show the photogeneration of equimolar superoxide and hydroxyl radical in desiccated and aqueous soils, respectively, by a photo-induced electron transfer mechanism supported by their mineralogical composition. Reactivity of desert soils is further supported by the generation of hydroxyl radical via aqueous extracts in the dark. Our findings extend to desert soils the photogeneration of reactive oxygen species by certain mineral oxides and also explain previous studies on desert soil organic oxidant chemistry and microbiology. Similar processes driven by ultraviolet radiation may be operating in the surface soils on Mars.

Oxidative status in different settings and with different methodological approaches compared by Receiver Operating Characteristic curve analysis

OBJECTIVES

To test the performance of different analytical approaches in highlighting the occurrence of deregulated redox status in various physio-pathological situations.

DESIGN AND METHODS

35 light and 61 heavy smokers, 19 chronic renal failure, 59 kidney transplanted patients, and 87 healthy controls were retrospectively considered for the study. Serum oxidative stress and antioxidant status, assessed by spectrophotometric Reactive Oxygen Metabolites (d-ROMs) and Total Antioxidant Capacity (TAC) tests, respectively, were compared with plasma free (F-MDA) and total (T-MDA) malondialdehyde, both quantified by isotope-dilution-gas chromatography-mass spectrometry (ID-GC-MS). Sensitivity, specificity and cut-off points of T-MDA, F-MDA, d-ROMs and TAC were evaluated by both Receiver Operating Characteristic (ROC) analyses and area under the ROC curve (AUC).

RESULTS

Only T-MDA assay showed a clear absence of oxidative stress in controls and significant increase in all patients (AUC 1.00, sensitivity and specificity 100%). Accuracy was good for d-ROMs (AUC 0.87, sensitivity 72.8%, specificity 100%) and F-MDA (AUC 0.82, sensitivity 74.7%, specificity 83.9%), but not high enough for TAC to show in patients impaired antioxidant defense (AUC 0.66, sensitivity 52.0%, specificity 92.9%).

CONCLUSIONS

This study reveals T-MDA as the best marker to detect oxidative stress, shows the ability of d-ROMs to identify modified oxidative status particularly in the presence of high damages, and evidences the poor TAC performance. d-ROMs and TAC assays could be useful for routine purposes; however, for an accurate clinical data evaluation, their comparison versus a "gold standard method" is required.

Targeting mitochondrially mediated plasticity to develop improved therapeutics for bipolar disorder

INTRODUCTION

Bipolar disorder (BPD) is a severe illness with few treatments available. Understanding BPD pathophysiology and identifying potential relevant targets could prove useful for developing new treatments. Remarkably, subtle impairments of mitochondrial function may play an important role in BPD pathophysiology.

AREAS COVERED

This article focuses on human studies and reviews evidence of mitochondrial dysfunction in BPD as a promising target for the development of new, improved treatments. Mitochondria are crucial for energy production, generated mainly through the electron transport chain (ETC) and play an important role in regulating apoptosis and calcium (Ca²⁺) signaling as well as synaptic plasticity. Mitochondria move throughout the neurons to provide energy for intracellular signaling. Studies showed polymorphisms of mitochondria-related genes as risk factors for BPD. Postmortem studies in BPD also show decreased ETC activity/expression and increased nitrosative and oxidative stress (OxS) in patient brains. BPD has been also associated with increased OxS, Ca²⁺ dysregulation and increased proapoptotic signaling in peripheral blood. Neuroimaging studies consistently show decreased energy levels and pH in brains of BPD patients.

EXPERT OPINION

Targeting mitochondrial function, and their role in energy metabolism, synaptic plasticity and cell survival, may be an important avenue for development of new mood-stabilizing agents.

Role of oxidative stress in Sclerotial differentiation and aflatoxin B1 biosynthesis in Aspergillus flavus

We show here that oxidative stress is involved in both sclerotial differentiation (SD) and aflatoxin B1 biosynthesis in Aspergillus flavus. Specifically, we observed that (i) oxidative stress regulates SD, as implied by its inhibition by antioxidant modulators of reactive oxygen species and thiol redox state, and that (ii) aflatoxin B1 biosynthesis and SD are comodulated by oxidative stress. However, aflatoxin B1 biosynthesis is inhibited by lower stress levels compared to SD, as shown by comparison to undifferentiated A. flavus. These same oxidative stress levels also characterize a mutant A. flavus strain, lacking the global regulatory gene veA. This mutant is unable to produce sclerotia and aflatoxin B1. (iii) Further, we show that hydrogen peroxide is the main modulator of A. flavus SD, as shown by its inhibition by both an irreversible inhibitor of catalase activity and a mimetic of superoxide dismutase activity. On the other hand, aflatoxin B1 biosynthesis is controlled by a wider array of oxidative stress factors, such as lipid hydroperoxide, superoxide, and hydroxyl and thiyl radicals.

Oxidative stress in early stage Bipolar Disorder and the association with response to lithium

BACKGROUND

Several studies have described increased oxidative stress (OxS) parameters and imbalance of antioxidant enzymes in Bipolar Disorder (BD) but few is know about the impact of treatment at these targets. However, no study has evaluated OxS parameters in unmedicated early stage BD and their association with lithium treatment in bipolar depression.

METHODS

Patients with BD I or II (n = 29) in a depressive episode were treated for 6 weeks with lithium. Plasma samples were collected at baseline and endpoint, and were also compared to age-matched controls (n = 28). The thiobarbituric acid reactive substances (TBARS), and the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were measured.

RESULTS

Subjects with BD depression at baseline presented a significant increase in CAT (p = 0.005) and GPx (p < 0.001) levels, with lower SOD/CAT ratio (p = 0.001) and no changes on SOD or TBARS compared to healthy controls. Regarding therapeutics, lithium only induced a decrease in TBARS (p = 0.023) and SOD (p = 0.029) levels, especially in BDII. Finally, TBARS levels were significantly lower at endpoint in lithium responders compared to non-responders (p = 0.018) with no difference in any biomarker regarding remission.

CONCLUSION

The present findings suggest a reactive increase in antioxidant enzymes levels during depressive episodes in early stage BD with minimal prior treatment. Also, decreased lipid peroxidation (TBARS) levels were observed, associated with lithium's clinical efficacy. Overall, these results reinforce the role for altered oxidative stress in the pathophysiology of BD and the presence of antioxidant effects of lithium in the prevention of illness progression and clinical efficacy.