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BACKGROUND/OBJECTIVES: Vitamin D, L-cysteine (LC) and glutathione (GSH) levels are lower in the blood of diabetic patients. This study examined the hypothesis that the levels of vitamin D and LC correlate with those of GSH in the blood of type 2 diabetic patients (T2D), and that vitamin D and LC upregulate glutamate-cysteine ligase (GCLC), which catalyzes GSH biosynthesis, in cultured monocytes. SUBJECTS/METHODS: Fasting blood was obtained after written informed consent from T2D (n = 79) and healthy controls (n = 22). U937 monocytes were pretreated with 1,25 [(OH).sub.2] vitamin D (0-25 nM) or LC (0-500 µM) for 24 h and then exposed to control or high glucose (25 mM) for 4 h. RESULTS: Plasma levels of vitamin D, LC, GSH and GCLC protein were significantly lower in T2D versus those in age-matched healthy controls. Multiple linear regression analyses and adjustment for body weight showed a significant positive correlation between plasma levels of vitamin D (r = 0.26, P = 0.05) and LC (r = 0.81, P = 0.001) and that of GSH, and between LC and vitamin D (r = 0.27, P = 0.045) levels. Plasma levels of GSH (r = -0.34, P = 0.01) and LC (r = -0.33, r = 0.01) showed a negative correlation with triglyceride levels. Vitamin D correlated inversely with [HbA.sub.1C] (-0.30, P = 0.01) and homeostatic model assessment insulin resistance (r = -0.31, P = 0.03), which showed a significant positive correlation with triglycerides (r = 0.44, P = 0.001) in T2D. Cell culture studies demonstrate that supplementation with vitamin D and LC significantly increased GCLC expression and GSH formation in control and high-glucose-treated monocytes. CONCLUSIONS: This study suggests a positive relationship between the concentrations of the micronutrients vitamin D and LC and that of GSH. Some of the beneficial effects of vitamin D and LC supplementation may be mediated by an increase in the levels of GSH and a decrease in triglyceride levels in T2D patients. European Journal of Clinical Nutrition (2014) 68, 1148-1153; doi: 10.1038/ejcn.2014.114; published online 25 June 2014, INTRODUCTION Reduced glutathione (GSH) is the most prevalent non-protein thiol found in mammalian cells. (1,2) GSH has a major role in the detoxification of a variety of electrophilic compounds, including [...]

Clinicians often report that their tried-and-true therapies do not seem to be working as well as they have in the past. In my own nutritional practice, there-was always a handful [...]

Individuals with type 2 diabetes are at increased risk of acquiring melioidosis, a disease caused by Burkholderia pseudomallei infection. Although up to half of melioidosis patients have underlying diabetes, the mechanisms involved in this increased susceptibility are unknown. We found that B. pseudomallei-infected PBMCs from dia-betic patients were impaired in IL-12p70 production, which resulted in decreased IFN-γ induction and poor bac-terial killing. The defect was specific to the IL-12-IFN- γ axis. Defective IL-12 production was also observed during Mycobacterium tuberculosis infection, in which diabetes is likewise known to be a strong risk factor. In contrast, IL-12 production in diabetic cells was not affected upon Salmonella enterica infection or in response to TLR2, -3, -4, and -5 ligands. Poor IL-12 production correlated with a deficiency in intracellular reduced glutathione (GSH) concentrations in diabetic patients. Addition of GSH or N-acetylcysteine to PBMCs selectively restored IL-12 and IFN- γ production and improved bacterial killing. Furthermore, the depletion of GSH in mice led to increased susceptibility to melioidosis, reduced production of IL-12p70, and poorer disease outcome. Our data thus establish a link between GSH deficiency in diabetes and increased susceptibility to melioidosis that may open up new therapeutic avenues to protect diabetic patients against some intracellular bacterial pathogens., Introduction Type 2 diabetes mellitus has been described as a global epidemic fueled by population growth, aging, urbanization, and increasing obesity. It is estimated that the number of people diagnosed [...]

The balance between GSH-levels and oxidative stress is critical for cell survival. The GSH-levels of erythrocytes are dramatically decreased during infection with Plasmodium spp. We therefore investigated the consequences of targeting GSH for erythrocyte and Plasmodium survival in vitro and in vivo using dimethylfumarate (DMF) at therapeutically established dosage. We first show that noninfected red blood cells (RBC) exposed to DMF undergo changes typical of apoptosis or eryptosis, such as cell shrinkage and cell membrane scrambling with subsequent phosphatidylserine (PS) exposure. DMF did not induce appreciable hemolysis. DMF-triggered PS exposure was mediated by intracellular GSH depletion and reversed by the antioxidative N-acetyl-L-cysteine. DMF treatment controlled intraerythrocyte DNA amplification and in vitro parasitemia of Plasmodium falciparum-infected RBC. In vivo, DMF treatment had no effect on RBC count or GSH levels in noninfected mice. Consistent with its effects on infected RBC, DMF treatment abrogated parasitemia and enhanced the survival of mice infected with Plasmodium berghei from 0% to 60%. In conclusion, DMF sensitizes the erythrocytes to the effect of Plasmodium infection on PS exposure, thus accelerating the clearance of infected erythrocytes. Accordingly, DMF treatment favorably influences the clinical course of malaria. As DMF targets mechanisms within the host cell, it is not likely to generate resistance of the pathogen. infection; erythrocytes; Plasmodium; phosphatidylserine doi: 10.1152/ajpcell.00014.2010.

Reactive oxygen species (ROS) produced from cigarette smoke cause oxidative lung damage including protein denaturation, lipid peroxidation, and DNA damage. Glutathione peroxidase-1 (gpx-1) is a detoxifying enzyme that may protect lungs from such damage. The aim of this study was to determine whether gpx-1 protects the lung against oxidative stress-induced lung inflammation in vivo. Male wild-type (WT) or [gpx-1.sup.-/-] mice were exposed to cigarette smoke generated from nine cigarettes per day for 4 days to induce oxidative stress and lung inflammation. The effect of the gpx mimetic ebselen on cigarette smoke-induced lung inflammation was evaluated when given prophylactically and therapeutically, i.e., during established inflammation. Mice were killed, and the lungs were lavaged with PBS and then harvested for genomic and proteomic analysis. [Gpx-l.sup.-/-] mice exposed to cigarette smoke had enhanced BALF neutrophils, macrophages, proteolytic burden, whole lung IL-17A, and MIPI[alpha] mRNA compared with WT mice. The gpx mimetic ebselen (10 and 100 [micro]M) inhibited cigarette smoke extract-induced oxidation of MH-S cells in vitro and inhibited cigarette smoke-induced increases in BALF macrophages, neutrophils, proteolytic burden, and macrophage and neutrophil chemotactic factor gene expression when administered prophylactically. In addition, ebselen inhibited established BALF inflammation when administered therapeutically. These data show that gpx-1 protects against cigarette smoke-induced lung inflammation, and agents that mimic the actions of gpx-1 may have therapeutic utility in inflammatory lung diseases where cigarette smoke plays a role. oxidative stress; reactive oxygen species; leukocyte; proteases; macrophage growth factors doi: 10.1152/ajplung.00038.2010.

Chronic kidney disease (CKD) is associated with accelerated atherosclerosis and cardiovascular disease, which is largely mediated by oxidative stress. We investigated the effect of three glutathione (GSH) precursors: N-acetyl-cysteine (NAC), cystine as the physiological carrier of cysteine in GSH with added selenomethionine (F1), and NAC fortified with selenomethionine (F2) on oxidative stress induced by spermine (a uremic toxin) in cultured human aortic vascular smooth muscle cells (VSMC). VSMC were exposed to spermine (15 [micro]M) with or without the given antioxidants (dose 50, 100, 200, and 500 [micro]g/ml) or vehicle (control) and assessed for intracellular GSH levels, 4-hydroxy-trans-2-nonenal (4-HNE), and incorporation of [sup.13]C from glucose into alanine and protein. Spermine exposure reduced intracellular GSH levels, increased 4-HNE, and impaired glucose metabolism through reduction in pyruvate generation and/or transamination. Treatment with NAC had no effect on intracellular glutathione level. In contrast, F1 maintained intracellular GSH at control levels at all four doses. Subsequent studies performed with 200 [micro]g/ml of F1, F2, or NAC (optimal dose) revealed normalization of 4-HNE, whereas restoration of [sup.13]C from glucose to alanine or protein to control values was only noted in the F1 group. Spermine-induced alterations in VSMC ultrastructure were prevented in ~90% of cells treated with F1 but only ~50% of cells treated with either NAC or F2. In conclusion, F1 was more effective than NAC or F2 in ameliorating spermine-induced reduction in intracellular GSH levels and cellular alterations in VSMC. The cystine-based GSH precursor (F1) is a promising antioxidant, and further studies are needed to examine the effect of this compound in preventing CKD-associated vascular disease. spermine; antioxidants; chronic kidney disease doi: 10.1152/ajpcell.00434.2009.

Glutaredoxin 1 (Glrx1) is a small dithiol protein that regulates the cellular redox state and redox-dependent signaling pathways via modulation of protein glutathionylation. I[kappa]B kinase (IKK), an essential enzyme for NF-[kappa]B activation, can be subjected to S-glutathionylation leading to alteration of its activity. However, the role of Glrx1 in cigarette smoke (CS)-induced lung inflammation and chromatin modifications are not known. We hypothesized that Glrx1 regulates the CS-induced lung inflammation and chromatin modifications via differential regulation of IKKs by S-glutathionylation in mouse lung. Glrxl knockout (KO) and wild-type (WT) mice were exposed to CS for 3 days and determined the role of Glrxl in regulation of proinflammatory response in the lung. Neutrophil influx in bronchoalveolar lavage fluid and proinflammatory cytokine release in lung were increased in Glrx1 KO mice compared with WT mice exposed to CS, which was associated with augmented nuclear translocation of RelA/ p65 and its phospho-acetylation. Interestingly, phosphorylated and total levels of IKK[alpha], but not total and phosphorylated IKK[beta] levels, were increased in lungs of Glrx1 KO mice compared with WT mice exposed to CS. Ablation of Glrx1 leads to increased CS-induced IKK[beta] glutathionylation rendering it inactive, whereas IKK[alpha] was activated resulting in increased phospho-acetylation of histone H3 in mouse lung. Thus, targeted disruption of Glrx1 regulates the lung proinflammatory response via histone acetylation specifically by activation of IKK[alpha] in response to CS exposure. Overall, our study suggests that S-glutathionylation and phosphorylation of IKK[alpha] plays an important role in histone acetylation on proinflammatory gene promoters and NF-[alpha]B-mediated abnormal and sustained lung inflammation in pathogenesis of chronic inflammatory lung diseases. NF-[kappa]B; glutathionylation; chronic obstructive pulmonary disease; oxidants: chromatin; glutathione doi: 10.1152/ajplung.00426.2009.

Oxidative stress plays an important role in the pathogenesis of pulmonary fibrosis. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme, and overexpression of HO-1 significantly decreases lung inflammation and fibrosis in animal models. Peroxisome proliferator-activated receptor-[gamma] (PPAR[gamma]) is a transcription factor that regulates adipogenesis, insulin sensitization, and inflammation. We report here that the PPAR[gamma] ligands 15d-[PGJ.sub.2] and 2-cyano-3,12-dioxoolean-l,9-dien-28-oic acid (CDDO), which have potent antifibrotic effects in vitro, also strongly induce HO-1 expression in primary human lung fibroblasts. Pharmacological and genetic approaches are used to demonstrate that induction of HO-1 is PPAR[gamma] independent. Upregulation of HO-1 coincides with decreased intracellular glutathione (GSH) levels and can be inhibited by N-acetyl cysteine (NAC), a thiol antioxidant and GSH precursor. Upregulation of HO-1 is not inhibited by Trolox, a non-thiol antioxidant, and does not involve the transcription factors AP-1 or Nrf2. CDDO and 15d-[PGJ.sub.2] contain an [alpha]/[beta] unsaturated ketone that acts as an electrophilic center that can form covalent bonds with free reduced thiols. Rosiglitazone, a PPAR[gamma], ligand that lacks an electrophilic center, does not induce HO-1. These data suggest that in human lung fibroblasts, 15d-[PGJ.sub.2] and CDDO induce HO-1 via a GSH-dependent mechanism involving the formation of covalent bonds between 15d-[PGJ.sub.2] or CDDO and GSH. Inhibiting HO-1 upregulation with NAC has only a small effect on the antifibrotic properties of 15d-[PGJ.sub.2] and CDDO in vitro. These results suggest that CDDO and similar electrophilic PPAR[gamma] ligands may have great clinical potential as antifibrotic agents, not only through direct effects on fibroblast differentiation and function, but indirectly by bolstering antioxidant defenses. 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid; myofibroblast; N-acetyl cysteine doi: 10.1152/ajplung.00148.2009.

The purpose of this study was to compare the antioxidant capacity of physically active middle-aged martial artists to age-matched sedentary controls. Nine sedentary subjects (mean age 52.9 yr) and 9 martial artists (mean age 51.8 yr) who practice Sod Bahk Do, a Korean martial art and were age- and sex-matched performed a graded exercise test (GXT) using a modified Bruce protocol. Ages ranged from 41 to 58 years. A GXT has been shown to be an effective technique for inducing oxidative stress. Glutathione (GSH) is the body's most highly concentrated antioxidant, is the central component of the antioxidant system, and plays an essential role in protecting tissues against oxidative stress. Free radical oxidation leads to the transformation of GSH to glutathione disulfide (GSSG). Venous blood samples for GSH and GSSG were collected before and immediately after the GXT. Repeated measures analysis of variance were performed on the resting baseline values and immediate post-GXT values of GSH, GSSG, and GSH:GSSG to compare groups. The blood GSH, GSSG, and GSH:GSSG levels were significantly different (p < 0.001) between the 2 groups at rest and after the GXT. The Sod Bahk Do practitioners had higher resting levels of GSH and lower levels of GSSG and responded more effectively to acute oxidative stress than the age-matched sedentary controls. Sod Bahk Do appears to enhance the antioxidant defense system and may be an effective intervention for improving overall health by protecting against the adverse effects of oxidative stress that is associated with the free radical theory of aging. Health professionals should be aware of alternative methods of training, conditioning, and exercise that can improve the general adaptation response to oxidative stress. KEY WORDS oxidative stress, free radicals, graded exercise testing, karate

Cigarette smoke (CS) induces a rapid, sustained upregulation of ceramide production in human bronchial epithelial cells, leading to increased apoptosis. Using loss-of-function and overexpression analyses, we show that neutral sphingo-myelinase 2 (nSMase2) is required for CS-mediated ceramide generation and apoptosis. Glutathione (GSH), a crucial antioxidant in lung defense, blocks nSMase2 activity and thus inhibits apoptosis triggered by CS. We found that the exposure to CS, as with exposure to [H.sub.2][O.sub.2], results in increased nSMase2 activation leading to ceramide generation and therefore increased apoptosis. Interestingly, exposure of cells to GSH abolishes nSMase2 activation caused by CS and leads to a decrease in CS-induced apoptosis. This suggests that the effects of CS oxidants on nSMase2 are counteracted by GSH. Our data support a model where CS induces nSMase2 activation thereby increasing membrane-sphingomyelin hydrolysis to ceramide. In turn, elevated ceramide enhances airway epithelial cell death, which causes bronchial and alveolar destruction and lung injury in pulmonary diseases. oxidative stress; airway epithelial cells; lung injury

Background: There has been an increasing interest in the role of oxidative stress in the pathophysiology of bipolar disorder. To explore this further, we evaluated the activity of glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST), as well as 3-nitrotyrosine levels and carbonyl content in patients in the early (within 3 years of illness onset) and late (a minimum of 10 years of illness) stages of bipolar disorder. Methods: We matched 30 patients in the early stage and 30 patients in the late stage of bipolar disorder, diagnosed according to DSM-IV criteria, with 60 healthy controls (30 matched for each group of patients). We measured symptomatic status using the Hamilton Rating Scale for Depression and the Young Mania Rating Scale. Results: We found a significant increase in 3-nitrotyrosine levels among patients in the early (p < 0.010) and late (p < 0.010) stages of bipolar disorder. The activity of GR and GST was increased only among patients in the late stage of illness. Glutathione peroxidase activity and carbonyl content did not differ among the groups. Limitations: Limitations of our study include its cross-sectional design, which did not allow us to examine direct causative mechanisms or the effects of progression of illness, and the potential environmental bias introduced by comparing patient groups recruited from different regions of the world. Conclusion: Our data indicate a possible tyrosine nitration-induced damage in patients with bipolar disorder that is present from the early stage of illness. Our data also indicate that patients in the late stage of illness demonstrate enhanced activity of GR and GST, which could suggest the involvement of a compensatory system in bipolar disorder., Introduction Bipolar disorder is a chronic psychiatric illness characterized by recurrent episodes of mania, hypomania, mixed states and depression. It is a highly disabling condition that is estimated to affect [...]

The reactions of glutathione (GSH) with polychlorinated biphenyl (PCB) quinones having different degrees of chlorination on the quinone ring were examined. EPR spectroscopy and MS revealed 2 types of reactions yielding different products: (i) a nonenzymatic, nucleophilic displacement of chlorine on the quinone ring yielding a glutathiylated conjugated quinone and (ii) Michael addition of GSH to the quinone, a 2-electron reduction, yielding a glutathiylated conjugated hydroquinone. The [pK.sub.a] of parent hydroquinone decreased by 1 unit as the degree of chlorination increased. This resulted in a corresponding increase in the oxidizability of these chlorinated hydroquinones. The reaction with oxygen appears to be first-order each in ionized hydroquinone and dioxygen, yielding hydrogen peroxide stoichiometrically. The generation of semiquinone radicals, superoxide, and hydroxyl radicals was observed by EPR; however, the mechanisms and yields vary depending on the degree of the chlorination of hydroquinone/quinone and the presence or absence of GSH. Our discovery that chlorinated quinones undergo a rapid, nonenzymatic dechlorination upon reaction with GSH opens a different view on mechanisms of metabolism and the toxicity of this class of compounds. dechlorination | EPR | superoxide | semiquinone | hydrogen peroxide

Cotton (Gossypium hirsutum L.) seedlings are considered to be sensitive to temperature stress. The exposure of plants to high and low temperatures can result in the production of reactive oxygen species that contribute to diminished plant performance. Plants have mechanisms that metabolize oxidants into less harmful chemicals, and enhancement of antioxidant metabolism has been shown to be beneficial to plants exposed to acute oxidative stresses. Transgenic overexpression of glutathione reductase (GR) in cotton could result in faster seedling emergence at nonoptimal temperatures. Transgenic GR and 5 nontransgenic cotton lines were planted at four dates in the field in Lubbock, TX, and in constant temperature growth boxes. The temperatures in the field were typical for the cotton planting period in the region, and in growth boxes ranged from 15 to 45[degrees]C. Emergence rates were determined for all lines, and the activity of GR and the levels of malondialdehyde in the cotyledons were monitored to verify altered enzyme activity and to detect differences in oxidative damage, respectively. Enhancement of GR activity did not improve emergence or reduce oxidative damage. It is concluded that GR activity did not limit emergence.

The effects of a 7.3-y supplementation with garlic and micronutrients and of anti-Helicobacter pylori treatment with amoxicillin (1 g twice daily) and omeprazole (20 mg twice daily) on serum folate, vitamin B-12, homocysteine, and glutathione concentrations were assessed in a rural Chinese population. A randomized, double-blind, placebo-controlled, factorial trial was conducted to compare the ability of 3 treatments to retard the development of precancerous gastric lesions in 3411 subjects. The treatments were: 1) anti-H, pylori treatment with amoxicillin and omeprazole; 2) 7.3-y supplementation with aged garlic and steam-distilled garlic oil; and 3) 7.3-y supplementation with vitamin C, vitamin E, and selenium. All 3 treatments were given in a [2.sup.3] factorial design to subjects seropositive for H. pylori infection; only the garlic supplement and vitamin and selenium supplement were given in a [2.sup.2] factorial design to the other subjects. Thirty-four subjects were randomly selected from each of the 12 treatment strata. Sera were analyzed after 7.3 y to measure effects on folate, vitamin B-12, homocysteine, and glutathione concentrations. Regression analyses adjusted for age, gender, and smoking indicated an increase of 10.2% (95%CI:2.9-18.1%) in serum folate after garlic supplementation and an increase of 13.4% (95%CI: 5.3-22.2%) in serum glutathione after vitamin and selenium supplementation. The vitamin and selenium supplement did not affect other analytes and the amoxicillin and omeprazole therapy did not affect any of the variables tested. In this rural Chinese population, 7.3 y of garlic supplementation increased the serum folate concentration and the vitamin and selenium supplement increased that of glutathione, but neither affected serum concentrations of vitamin B-12 or homocysteine.

Organometallic complexes offer chemistry that is not accessible to purely organic molecules and, hence, potentially new mechanisms of drug action. We show here that the presence of both an iodido ligand and a [sigma]-donor/[pi]-acceptor phenylazopyridine ligand confers remarkable inertness toward ligand substitution on the half-sandwich 'piano-stool' ruthenium arene complexes [[([[eta].sup.6]-arene)Ru(azpy)l].sup.+] (where arene = p-cymene or biphenyl, and azpy = N,N-dimethylphenylor hydroxyphenyl-azopyridine) in aqueous solution. Surprisingly, despite this inertness, these complexes are highly cytotoxic to human ovarian A2780 and human lung A549 cancer cells. Fluorescence-trapping experiments in A549 cells suggest that the cytotoxicity arises from an increase in reactive oxygen species. Redox activity of these azopyridine [Ru.sup.11] complexes was confirmed by electrochemical measurements. The first one-electron reduction step (half-wave potential -0.2 to -0.4 V) is assignable to reduction of the azo group of the ligand. In contrast, the unbound azopyridine ligands are not readily reduced. Intriguingly the ruthenium complex acted as a catalyst in reactions with the tripeptide glutathione ([gamma]-L-Glu-L-Cys-Gly), a strong reducing agent present in cells at millimolar concentrations; millimolar amounts of glutathione were oxidized to glutathione disulfide in the presence of micromolar ruthenium concentrations. A redox cycle involving glutathione attack on the azo bond of coordinated azopyridine is proposed. Such ligand-based redox reactions provide new concepts for the design of catalytic drugs. arenes | cytotoxicity | glutathione | redox reactions | ruthenium complexes

Pancreatic 13-cells are susceptible to oxidative stress, which is related closely to the islet dysfunction. In the present study, using the pancreatic cell lines HIT-T15 and RINm5F as known in vitro models of impaired [beta]-cell function as well as primary rat islet [beta]-cells, we observed a relationship between intracellular glutathione levels and oxidative stress-mediated cell dysfunction. Hydrogen peroxide and 4-hydroxy2-nonenal caused cell death in HIT-T15 and RINm5F cells at lower concentrations compared with non-[beta]-cells, such as HepG2 and NRK49F cells. The extent of the cytotoxicity caused by the model oxidants was inversely correlated well with intracellular glutathione levels in the cell lines used. Treatment of HIT-T15 and RINm5F cells with L-cysteine or L-cystine significantly augmented the glutathione contents, surpassing the effect of N-acetylcysteine, and abrogated 4-hydroxy-2-nonenal-mediated cytotoxicity almost completely. L-Cysteine increased intracellular glutathione levels in primary [beta]-cells as well. Supplementation of L-cysteine to the RINm5F cell culture inhibited 4-hydroxy-2-nonenal-mediated cytosolic translocation of PDX-1, a key transcription factor for [beta]-cell function. Intrinsic transport activities ([V.sub.max]/[K.sub.m]) of the L-cystine/L-glutamate exchanger in HIT-T15 and RINm5F cells were considerably lower than that in NRK-49F cells, although gene expressions of the exchanger were similar in these cells. Results obtained from the present study suggest that the restricted activity of the L-cystine/L-glutamate exchanger controls the levels of intracellular glutathione, thereby making [beta]-cells become susceptible to oxidative stress. system [x.sup.-.sub.c]; glutathione; hydrogen peroxide; reactive oxygen species; PDX-1

There is accumulating evidence for oxidative stress mechanisms as common pathophysiological pathways in diverse psychiatric disorders, which offers novel treatment targets in oxidation biology systems. Of these the glutathione system has the most favourable theoretical foundation, given its dominance as the most generic of cellular antioxidants. Clinically, this hypothesis has been supported by several recently published studies that have reported on the efficacy of N-acetylcysteine, a glutathione precursor, in the treatment of various psychiatric disorders. This article outlines the multidimensional evidence that currently exists for oxidative stress mechanisms in psychiatric disorders and specifically discusses glutathione as a promising novel therapeutic target.

BACKGROUND: Exposure to toxic methylmercury (MeHg) through fish consumption is a large problem worldwide, and it has led to governmental recommendations of reduced fish consumption and blacklisting of mercury-contaminated fish. [...]

Glutathione peroxidase 4 (Gpx4) is an antioxidant defense enzyme that plays an important role in detoxification of oxidative damage to membrane lipids. Because oxidative stress is proposed to play a causal role in aging, we compared the life spans of Gpx4 heterozygous knockout mice ([Gpx4.sup.+/-] mice) and wild-type mice (WT mice). To our surprise, the median life span of [Gpx4.sup.+/-] mice (1029 days) was significantly longer than that of WT mice (963 days) even though the expression of Gpx4 was reduced approximately 50% in all tissues of [Gpx4.sup.+/-] mice. Pathological analysis revealed that [Gpx4.sup.+/-] mice showed a delayed occurrence of fatal tumor lymphoma and a reduced severity of glomerulonephritis. Compared to WT mice, [Gpx4.sup.+/-] mice showed significantly increased sensitivity to oxidative stress-induced apoptosis. Our data indicate that lifelong reduction in Gpx4 increased life span and reduced/retarded age-related pathology most likely through alterations in sensitivity of tissues to apoptosis.

The generation of reactive oxygen species (ROS) and resultant oxidative stress has been implicated in the mechanism of brain dysfunction due to age-related neurodegenerative diseases. We have evaluated the efficacy of glutathione monoester (GME) when administered intraperitoneally (12 mg/kg body weight) for 20 days on glutathione, ROS, superoxide anion production, lipid peroxidation (LPO), protein carbonyls, thiol status, oxidative DNA damage products such as 8-hydroxy deoxy guanosine and DNA protein cross-links in discrete brain regions of young and aged rats. An age associated increase in ROS, superoxide anion production, LPO, protein oxidation, and DNA damage products in cortex, striatum, and hippocampus was observed which was reversed by GME. Contradictorily, a decline in the levels of glutathione, total thiol, and nonprotein and protein thiols was observed which was also reversed upon GME administration. These findings suggest that GME administration inhibits free radical-induced oxidative macromolecular damage in aged rats and thereby protects the brain from ROS.

Reactive iron is an important prooxidant factor, whereas GSH is a crucial component of a long-term adaptive system that allows cells to function during extended periods of high oxidative stress. In this work, the adaptive response of the GSH system to prolonged iron loads was characterized in human dopaminergic SH-SY5Y neuroblastoma cells. After the initial death of a substantial portion of the cell population, the surviving cells increased their GSH content by up to fivefold. This increase was traced to increased expression of the catalytic and modulatory subunits of [gamma]-glutamate-cysteine ligase. Under conditions of high iron load, cells maintained a low GSSG content through two mechanisms: 1) GSSG reductase-mediated recycling of GSSG to GSH and 2) multidrug resistant protein 1-mediated extrusion of GSSG. Increased GSH synthesis and low GSSG levels contributed to recover the cell reduction potential from -290 mV at the time of cell death to about -320 mV. These results highlight the fundamental role of GSH homeostasis in the antioxidant response to cellular iron accumulation and provide novel insights into the adaptive mechanisms of neurons subjected to increased iron loads, such as those observed in Parkinson's disease. oxidative stress; glutathione; multidrug resistance protein 1; oxidixed glutathione reductase; neurodegenerative diseases doi:10.1152/ajpcell.00620.2006

The acid-sensing ion channels (ASICs) are voltage-independent ion channels activated by acidic extracellular pH. ASICs play a role in sensory transduction, behavior, and acidotoxic neuronal death, which occurs during stroke and ischemia. During these conditions, the extracellular concentration of sulfhydryl reducing agents increases. We used perforated patch-clamp technique to analyze the impact of sulfhydryls on [H.sup.+]-gated currents from Chinese hamster ovary (CHO) cells expressing human ASIC1a (hASIC1a). We found that hASIC1a currents activated by pH 6.5 were increased almost twofold by the sulfhydryl-containing reducing agents dithiothreitol (DTT) and glutathione. DTT shifted the pH-dose response of hASIC1a toward a more neutral pH ([pH.sub.0.5] from 6.54 to 6.69) and slowed channel desensitization. The effect of reducing agents on native mouse hippocampal neurons and transfected mouse ASIC1a was similar. We found that the effect of DTT on hASIC1a was mimicked by the metal chelator TPEN, and mutant hASIC1a channels with reduced TPEN potentiation showed reduced DTT potentiation. Furthermore, the addition of DTT in the presence of TPEN did not result in further increases in current amplitude. These results suggest that the effect of DTT on hASIC1a is due to relief of tonic inhibition by transition metal ions. We found that all ASICs examined remained potentiated following the removal of DTT. This effect was reversed by the oxidizing agent DTNB in hASIC1a, supporting the hypothesis that DTT also impacts ASICs via a redox-sensitive site. Thus sulfhydryl compounds potentiate [H.sup.+]-gated currents via two mechanisms, metal chelation and redox modulation of target amino acids. glutathione; DTT; redox; zinc doi:10.1152/ajpcell.00598.2006

Limited data in animal models suggest that colonic mucosa undergoes adaptive growth following massive small bowel resection (SBR). In vitro data suggest that intestinal cell growth is regulated by reactive oxygen species and redox couples [e.g., glutathione (GSH)/glutathione disulfide (GSSG) and cysteine (Cys)/cystine (CySS) redox]. We investigated the effects of SBR and alterations in redox on colonic growth indexes in rats after either small bowel transection (TX) or 80% midjejunoileal resection (RX). Rats were pair fed [+ or -] blockade of endogenous GSH synthesis with buthionine sulfoximine (BSO). Indexes of colonic growth, proliferation, and apoptosis and GSH/GSSG and Cys/CySS redox potentials ([E.sub.h]) were determined. RX significantly increased colonic crypt depth, number of cells per crypt, and epithelial cell proliferation [crypt cell bromodeoxyuridine (BrdU) incorporation]. Administration of BSO markedly decreased colonic mucosal GSH, GSSG, and Cys concentrations in both TX and RX groups, with a resultant oxidation of GSH/GSSG and Cys/CySS [E.sub.h]. BSO did not alter colonic crypt cell apoptosis but significantly increased all colonic mucosal growth indexes (crypt depth, cells/crypt, and BrdU incorporation) in both TX and RX groups in a time- and dose-dependent manner. BSO significantly decreased plasma GSH and GSSG, oxidized GSH/GSSG [E.sub.h], and increased plasma Cys and CySS concentrations. Collectively, these data provide in vivo evidence indicating that oxidized colonic mucosal redox status stimulates colonic mucosal growth in rats. The data also suggest that GSH is required to maintain normal colonic and plasma Cys/CySS homeostasis in these animal models. cysteine; colon; glutathione; intestine; short bowel syndrome

Reactive oxygen species (ROS) and the cellular thiol redox state are crucial mediators of multiple cell processes like growth, differentiation, and apoptosis. Excessive ROS production or oxidative stress is associated with several diseases, including cardiovascular disorders like ischemia-reperfusion. To prevent ROS-induced disorders, the heart is equipped with effective antioxidant systems. Key players in defense against oxidative stress are members of the thioredoxin-fold family of proteins. Of these, thioredoxins and glutaredoxins maintain a reduced intracellular redox state in mammalian cells by the reduction of protein thiols. The reversible oxidation of Cys-Gly-Pro-Cys or Cys-Pro(Ser)-Tyr-Cys active site cysteine residues is used in reversible electron transport. Thioredoxins and glutaredoxins belong to corresponding systems consisting of NADPH, thioredoxin reductase, and thioredoxin or NADPH, glutathione reductase, glutathione, and glutaredoxin, respectively. Thioredoxin as well as glutaredoxin activities appear to be very important for the progression and severity of several cardiovascular disorders. These proteins function not only as antioxidants, they inhibit or activate apoptotic signaling molecules like apoptosis signal-regulating kinase 1 and Ras or transcription factors like NF-[kappa]B. Thioredoxin activity is regulated by the endogenous inhibitor thioredoxin-binding protein 2 (TBP-2), indicating an important role of the balance between thioredoxin and TBP-2 levels in cardiovascular diseases. In this review, we will summarize cardioprotective effects of endogenous thioredoxin and glutaredoxin systems as well as the high potential in clinical applications of exogenously applied thioredoxin or glutaredoxin or the induction of endogenous thioredoxin and glutaredoxin systems. oxidative stress; thiol-disulfide oxidoreductases; apoptotic signaling; myocardial remodeling; glutathione

Glutathione (GSH)-conjugated xenobiotics and GSH-conjugated metabolites (e.g. the cysteinyl leukotriene [C.sub.4]) must be exported from the cells in which they are formed before they can be eliminated from the body or act on their cellular targets. This efflux is often mediated by the multidrug resistance protein 1 (MRP1) transporter, which also confers drug resistance to tumour cells and can protect normal cells from toxic insults. In addition to drugs and GSH conjugates, MRP1 exports GSH and GSH disulfide, and might thus have a role in cellular responses to oxidative stress. The transport of several drugs and conjugated organic anions by MRP1 requires the presence of GSH, but it is not well understood how GSH (and its analogues) enhances transport. Site-directed mutagenesis studies and biophysical analyses have provided important insights into the structural determinants of MRP1 that influence GSH and GSH conjugate binding and transport.

Background Levels of glutathione (GSH) in antigen-presenting cells promote a T-helper type 2 (Th2) cytokine response in mice. We have previously demonstrated that we can increase intracellular GSH levels in healthy young adults using a whey-based oral supplement (HMS90[TM]). We hypothesized that such supplementation in children with atopic asthma, a Th2 cytokine disease, would improve lung function and decrease atopy. Methods Eleven children (six females, five males; mean[+ or -]standard deviation age, 12.6[+ or -]3.6 years; baseline forced expired volume in 1 sec ([FEV.sub.1]), 82.4[+ or -]15.4%predicted), underwent spirometry, methacholine provocation testing, and blood analysis for serum IgE and lymphocyte GSH before and after 1 month of supplementation (10 g twice daily). Results Initially the IgE was 1689 [+ or -] 1596 [micro]g/l (normal range [less than or equal to] 240 [micro]g/l) and lymphocyte GSH was 1.75[+ or -]0.48 [micro]M (normal range 1.55[+ or -]0.33 [micro]M). IgE significantly decreased to 1379[+ or -] 1329 [micro]g/1 (P < 0.05) following supplementation. Although no significant changes in lymphocyte GSH or [FEV.sub.1] were found for the group as a whole, the two patients with significant increases in lymphocyte GSH concentrations were the only two to demonstrate reductions in methacholine provocation doses (provocative concentration causing a 20% fall in [FEV.sub.1]). Conclusions These results suggest a modest impact of whey protein supplementation on the cytokine response in atopic asthma. Supplementation for longer periods, or with more potent whey-based supplements, currently under development, may prove more beneficial. Keywords: IgE, glutathione, whey protein, nutritional supplementation

Cysteine synthesis from homocysteine is catalyzed by two pyridoxal 5'-phosphate (PLP)-dependent enzymes. This suggests that vitamin B-6 status might affect cysteine and glutathione homeostasis, but it is unclear whether this occurs in humans. We assessed the effects of vitamin B-6 status on static and kinetic parameters of cysteine and glutathione metabolism in healthy female (n = 5) and male (n = 4) volunteers (20-30 y) before and after 4 wk of dietary vitamin B-6 restriction ( KEY WORDS: * cysteine * glutathione * human * transsulfuration * vitamin B-6

Abstract The aim of this study was to investigate the effects of aqueous extract of Anoectochilus formosanus (AFE) on liver fibrogenesis in carbon tetrachloride (C[Cl.sub.4])-induced cirrhosis. Fibrosis was induced in [...]

Byline: U. B. Flaring (1), O. E. Rooyackers (2), J. Wernerman (2), F. Hammarqvist (3,4) Keywords: Glutathione; Glutamate; Amino acids; Skeletal muscle; Critical illness; Multiple organ failure Abstract: Objective This study investigated the changes over time in glutathione and its constituent amino acids in skeletal muscle of ICU patients with multiple organ failure. Design and setting Prospective and descriptive pilot study in two medium-sized ICUs with ten beds. Patients Critically ill patients (n=10) with multiple organ failure and with an expected ICU stay longer than 6 days were included during their initial 3 days after admission to the ICU. Measurements and results Muscle biopsy and blood samples were taken on days 0, 3, and 6 after inclusion and total, reduced, and oxidized glutathione and the related amino acids were determined. During the study period both total and reduced glutathione increased and was in the normal range on day 6. The constituent amino acids normalized during the study period as well. Conclusions This pilot study demonstrates a recovery of muscle glutathione concentrations in critically ill patients with ongoing multiple organ failure within 1 week. Restoration of muscle glutathione seems to be a biological process of high priority in this group of patients. Author Affiliation: (1) Department of Anaesthesia and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska Hospital, 17176, Stockholm, Sweden (2) Department of Anaesthesia and Intensive Care, Huddinge University Hospital, Sweden (3) Gastrocentrum at the Department of Surgery, Huddinge University Hospital, Sweden (4) Clinical Research Laboratory, St Gorans Hospital, Stockholm, Sweden Article History: Received Date: 11/05/2003 Accepted Date: 08/09/2003 Online Date: 18/10/2003