Search results for "GPX"
showing 10 items of 54 documents
Moderate weight loss attenuates chronic endoplasmic reticulum stress and mitochondrial dysfunction in human obesity
2018
Abstract Objective In obese patients undergoing caloric restriction, there are several potential mechanisms involved in the improvement of metabolic outcomes. The present study further explores whether caloric restriction can modulate endoplasmic reticulum (ER) stress and mitochondrial function, as both are known to be mechanisms underlying inflammation and insulin resistance (IR) during obesity. Methods A total of 64 obese patients with BMI ≥35 kg/m2 underwent a dietary program consisting of 6 weeks of a very-low-calorie diet followed by 18 weeks of low-calorie diet. We evaluated changes in the metabolic and inflammatory markers -TNFα, hsCRP, complement component 3 (C3c), and retinol bindi…
Roles of sedentary aging and lifelong physical activity in exchange of glutathione across exercising human skeletal muscle.
2014
Reactive oxygen species (ROS) are important signaling molecules with regulatory functions, and in young and adult organisms, the formation of ROS is increased during skeletal muscle contractions. However, ROS can be deleterious to cells when not sufficiently counterbalanced by the antioxidant system. Aging is associated with accumulation of oxidative damage to lipids, DNA, and proteins. Given the pro-oxidant effect of skeletal muscle contractions, this effect of age could be a result of excessive ROS formation. We evaluated the effect of acute exercise on changes in blood redox state across the leg of young (23±1 years) and older (66±2 years) sedentary humans by measuring the whole blood co…
Glutathione Peroxidase-1 Deficiency Potentiates Dysregulatory Modifications of Endothelial Nitric Oxide Synthase and Vascular Dysfunction in Aging
2014
Recently, we demonstrated that gene ablation of mitochondrial manganese superoxide dismutase and aldehyde dehydrogenase-2 markedly contributed to age-related vascular dysfunction and mitochondrial oxidative stress. The present study has sought to investigate the extent of vascular dysfunction and oxidant formation in glutathione peroxidase-1–deficient ( GPx-1 −/− ) mice during the aging process with special emphasis on dysregulation (uncoupling) of the endothelial NO synthase. GPx-1 −/− mice on a C57 black 6 (C57BL/6) background at 2, 6, and 12 months of age were used. Vascular function was significantly impaired in 12-month-old GPx-1 −/− -mice as compared with age-matched controls. Oxidan…
Expression of NO synthases and redox enzymes in umbilical arteries from newborns born small, appropriate, and large for gestational age.
2012
Modified expression of nitric oxide synthases (NOSs) and an imbalance between the pro-oxidative and the antioxidative system accompany endothelial dysfunction, the first stage of atherosclerosis. Humans born small (SGA) or large (LGA) for gestational age are at higher risk of developing atherosclerosis later in life than humans born appropriate for gestational age (AGA). We hypothesized that indicators of endothelial dysfunction could be detectable at birth. The purpose of this study was to find out whether the expression patterns of NO synthases (endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS)), pro-oxidative enzymes (components of nicotinamide adenine dinucleotide ph…
The distribution, induction and isoenzyme profile of glutathione S-transferase and glutathione peroxidase in isolated rat liver parenchymal, Kupffer …
1989
The distribution and inducibility of cytosolic glutathione S-transferase (EC 2.5.1.18) and glutathione peroxidase (EC 1.11.1.19) activities in rat liver parenchymal, Kupffer and endothelial cells were studied. In untreated rats glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and 4-hydroxynon-2-trans-enal as substrates was 1.7-2.2-fold higher in parenchymal cells than in Kupffer and endothelial cells, whereas total, selenium-dependent and non-selenium-dependent glutathione peroxidase activities were similar in all three cell types. Glutathione S-transferase isoenzymes in parenchymal and non-parenchymal cells isolated from untreated rats were separated by chromatofocusing …
Calcium overload increases oxidative stress in old rat gastrocnemius muscle
2005
International audience; In order to challenge in vivo muscle Ca2+ homeostasis and analyze consequences on mitochondrial H2O2 release (MHR) and sarcopenia, we injected Ca2+ ionophore A23187 (200 µg/kg, ip) in adult and old rats and measured gastrocnemius mass and mitochondrial Ca2+ content (MCC) using radioactive Ca2+ 48 h after injection. In a second experiment performed in old rats, we measured isocitrate dehydrogenase (ICDH) activity as an index of MCC, MHR, mitochondrial respiration, citrate synthase, COX and antioxydant enzyme activities 24 h after a 150 µg/kg injection. In adult rats, muscle mass and MCC were unchanged by A23187. In old rats, MCC increased 24 h after injection as refle…
Different impacts of cardiovascular risk factors on oxidative stress.
2011
The objective of the study was to evaluate oxidative stress (OS) status in subjects with different cardiovascular risk factors. With this in mind, we have studied three models of high cardiovascular risk: hypertension (HT) with and without metabolic syndrome, familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH) with and without insulin resistance. Oxidative stress markers (oxidized/reduced glutathione ratio, 8-oxo-deoxyguanosine and malondialdehide) together with the activity of antioxidant enzyme triad (superoxide dismutase, catalase, glutathione peroxidase) and activation of both pro-oxidant enzyme (NAPDH oxidase components) and AGTR1 genes, as well as antioxidant…
Regulation of glutathione metabolism in Ehrlich ascites tumour cells.
1992
Glutathione metabolism was studied in cancer cells during the growth of an Ehrlich ascites tumour. GSH, but not GSSG, content decreases when cell proliferation and the rate of protein synthesis in the tumour decrease. This change correlates with a decrease in the rate of GSH synthesis and an increase in glutathione peroxidase and glutathione S-transferase activities. Glutathione efflux from tumour cells seems to co-ordinate with the rate of GSH synthesis. Cysteine, and not methionine, promotes GSH synthesis in tumour cells. However, changes in the rate of GSH synthesis are not due to limitations in the supply of blood cysteine or to changes in the intracellular amino acid pool of the cancer…
Part of the Series: From Dietary Antioxidants to Regulators in Cellular Signalling and Gene ExpressionRole of reactive oxygen species and (phyto)oest…
2006
There is increasing evidence that reactive oxygen species (ROS) are not only toxic but play an important role in cellular signalling and in the regulation of gene expression. We, here, discuss two examples of improved adaptive response to an altered cellular redox state. First, differences in longevity between males and females may be explained by a higher expression of antioxidant enzymes in females resulting in a lower yield of mitochondrial ROS. Oestrogens are made responsible for these phenomena. Oestradiol induces glutathione peroxidase-1 and MnSOD by processes requiring the cell surface oestrogen receptor (ER) and the activation of pathways usually involved in oxidative stress respons…
Glutathione Peroxidase 1 Activity and Cardiovascular Events in Patients With Coronary Artery Disease
2003
Along with superoxide dismutase, glutathione peroxidase 1 is one of the cellular antioxidant enzymes that have a key role in controlling reactive oxygen species. It uses glutathione to reduce hydrogen peroxide to water and lipid peroxides to their respective alcohols. There are suggestions from in vitro and animal studies that these enzymes could protect against atherosclerosis. This prospective study examined the possibility that relatively high activity of antioxidant enzymes protects against cardiovascular events. The study population included 636 patients suspected of having coronary artery disease who were followed for a median period of 4.7 years. Stable angina was present in 510 pati…