Search results for "oxidation"
showing 10 items of 1913 documents
Betanin inhibits the myeloperoxidase/nitrite-induced oxidation of human low-density lipoproteins
2007
Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scaven…
Cytoprotective effect of resveratrol diastereomers in CHO-K1 cells exposed to beauvericin
2015
Beauvericin (BEA) causes cytotoxicity, lipid peroxidation and reactive oxygen species in CHO-K1 cells. Resveratrol (RSV) is a polyphenol with multiple biological properties, including antioxidant effects. RSV has two forms: trans and cis. The aims of this study were to determine the cytoprotective effect of trans-RSV and diastereomers mixtures (50:50 trans/cis-RSV and 70:30 trans/cis-RSV) incubated alone and in combination with BEA in ovarian (CHO-K1) cells. The results demonstrated that cell viability increases (from 9% to 77%) when they were exposed to low concentration of RSV. Moreover, when the cells were pre-treated with RSV and then exposed to BEA, a cytoprotective effect (from 25% to…
Antioxidant capacity of trans -resveratrol dietary supplements alone or combined with the mycotoxin beauvericin
2017
Trans-resveratrol (trans-RSV) is a polyphenol with multiples biological properties, such as anti-inflammatory, antioxidant, anti-aging, anti-diabetic, and antiplatelet. It occurs naturally in grapes and derivate, peanuts and berries. Beauvericin (BEA) is a mycotoxin present in cereals that produces cytotoxicity, intracellular reactive oxygen species and lipid peroxidation. The general objective of this research was to evaluate whether trans-RSV could be used as a good polyphenol against damages produced by BEA. Because trans-RSV can be ingested through dietary supplements, to reach this goal, the following specific objectives were proposed: to determine a) the trans-RSV content in different…
ETC-1002: A future option for lipid disorders?
2014
ETC-1002 is a new investigational low density lipoprotein cholesterol (LDL-C)-lowering agent (Esperion Therapeutics, Inc.). ETC-1002 is a dicarboxylic acid derivative with a novel mechanism of action targeting two hepatic enzymes - adenosine triphosphate-citrate lyase (ACL) and adenosine monophosphate-activated protein kinase (AMPK), inhibiting sterol and fatty acid synthesis and promoting mitochondrial long-chain fatty acid oxidation. This agent is currently in phase II clinical research. Available data report that ETC-1002 significantly decreased LDL-C levels (up to 32%) in both patients with normal and elevated baseline levels of triglycerides. Such beneficial effect is superior to curre…
Reductive stress in young healthy individuals at risk of Alzheimer disease.
2013
Oxidative stress is a hallmark of Alzheimer disease (AD) but this has not been studied in young healthy persons at risk of the disease. Carrying an Apo e4 allele is the major genetic risk factor for AD. We have observed that lymphocytes from young, healthy persons carrying at least one Apo e4 allele suffer from reductive rather than oxidative stress, i.e., lower oxidized glutathione and P-p38 levels and higher expression of enzymes involved in antioxidant defense, such as glutamylcysteinyl ligase and glutathione peroxidase. In contrast, in the full-blown disease, the situation is reversed and oxidative stress occurs, probably because of the exhaustion of the antioxidant mechanisms just ment…
Low and very low density lipoprotein composition and resistance to copper-induced oxidation are not notably modified in smokers.
1997
To study whether tobacco use was associated with oxidative phenomena affecting lipoproteins, we estimated susceptibility of LDL and VLDL to an in vitro copper-mediated oxidation, and measured serum autoantibody titers against oxidized LDL in 45 middle-age healthy nonsmokers, 35 smokers and 37 ex-smokers of both sexes, taking into account the detailed lipid composition of the lipoproteins. VLDL from female smokers had higher triglyceride, phospholipid, apolipoprotein E and alpha-tocopherol content and showed a higher rate of copper-induced oxidation in comparison with those from nonsmokers (P < or = 0.05) whereas the relative composition of these particles in saturated, mono- or poly-unsatur…
Increased Atherosclerotic Lesions in ApoE Mice With Plasma Phospholipid Transfer Protein Overexpression
2003
Objective— Plasma phospholipid transfer protein (PLTP) is involved in the metabolism of HDL and apolipoprotein B (apoB)-containing lipoproteins. Atherosclerosis susceptibility is decreased in mice with PLTP deficiency that is associated with decreased liver production of apoB-containing lipoproteins and increase in their antioxidant. To investigate additionally the effect of PLTP on the development of atherosclerosis, we overexpressed PLTP in mice. Methods and Results— PLTP was overexpressed in apoE knockout mice using an adenovirus-associated virus (AAV)-mediated system. Plasma PLTP activity was 1.3- to 2-fold higher in mice injected with AAV-PLTP than in mice injected with control AAV-GF…
Deficiency of glutathione peroxidase-1 accelerates the progression of atherosclerosis in apolipoprotein E-deficient mice.
2007
Background— We have recently demonstrated that activity of red blood cell glutathione peroxidase-1 is inversely associated with the risk of cardiovascular events in patients with coronary artery disease. The present study analyzed the effect of glutathione peroxidase-1 deficiency on atherogenesis in the apolipoprotein E-deficient mouse. Methods and Results— Female apolipoprotein E-deficient mice with and without glutathione peroxidase-1 deficiency were placed on a Western-type diet for another 6, 12, or 24 weeks. After 24 weeks on Western-type diet, double-knockout mice (GPx-1 −/− ApoE −/− ) developed significantly more atherosclerosis than control apolipoprotein E-deficient mice. Moreover…
Opposite vascular activity of (R)-apomorphine and its oxidised derivatives. Endothelium-dependent vasoconstriction induced by the auto-oxidation meta…
2003
We have synthetised a series of oxidised apomorphine derivatives (orto and para quinones 2-5), in order to analyse their vascular activity. We have performed radioligand binding assays on rat cortical membranes and functional studies on rat aortic rings. Instead the relaxant activity exhibited by (R)-apomorphine, o-quinones 2, 4, show contractile activity dependent on endothelium in rat aortic rings. Compound 2, the main metabolite of (R)-apomorphine auto-oxidation, was the product which showed enhanced contractile activity by a complex mechanism related to activation of Ca(2+) channels through release and/or inhibition of endothelial factors. Moreover, this compound disrupts the endothelia…
Superoxide Flux in Endothelial Cells via the Chloride Channel-3 Mediates Intracellular Signaling
2007
Reactive oxygen species (ROS) have been implicated in both cell signaling and pathology. A major source of ROS in endothelial cells is NADPH oxidase, which generates superoxide (O2.−) on the extracellular side of the plasma membrane but can result in intracellular signaling. To study possible transmembrane flux of O2.−, pulmonary microvascular endothelial cells were preloaded with the O2.−-sensitive fluorophore hydroethidine (HE). Application of an extracellular bolus of O2.−resulted in rapid and concentration-dependent transient HE oxidation that was followed by a progressive and nonreversible increase in nuclear HE fluorescence. These fluorescence changes were inhibited by superoxide dism…