Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0242339 (dyslipidemia)
 13,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyperglycemia increases oxidative stress in various tissues and leads to diabetic cardiovascular complication. Dyslipidemia, such as an increase in oxidized low-density lipoprotein (LDL), is well recognized in diabetic patients with hyperglycemia. However, the mechanism by which hyperglycemia causes the increased LDL oxidation remains unclear. Albumin is the most abundant protein in the circulation, and can function as an antioxidant. Therefore, we examined whether glycoxidative modification inhibits the antioxidant activity of albumin to LDL oxidation and clarified the mechanism by which this modification may suppress its antioxidant activity. Human serum albumin (HSA) was incubated in phosphate-buffered saline with and without glucose at 37 degrees C for up to 8 weeks under aerobic conditions (referred to as glycoxidation (goHSA) and oxidation (oHSA), respectively). Metal chelator-treated, nonoxidative HSA (chHSA) and freshly prepared HSA (fHSA) were used as controls. N(epsilon)-(carboxymethyl)lysine (CML), a glycoxidative product, was determined by enzyme-linked immunosorbent assay. Oxidation was estimated by measuring the thiols of the HSA molecule. Copper-mediated oxidation of LDL was conducted in the presence or absence of modified HSAs at 37 degrees C for 6 days. Malondialdehyde and negative charge of LDL were measured. To clarify the mechanism of reduced antioxidant activity of HSA, we examined firstly the binding activity of modified HSAs to copper, and secondly the effects of free radical scavengers on the formation of malondialdehyde. CML was formed in goHSA in a time- and concentration-dependent manner. Both goHSA and oHSA significantly decreased the contents of free thiol groups compared to ch- and fHSAs. The antioxidant activity of goHSA to LDL oxidation was the lowest among various modified HSAs. The oHSA showed a moderate decrease in antioxidant activity. The binding activity of go- and oHSAs to copper was lower than that of ch- and fHSAs. The formation of MDA from LDL oxidation in the presence of goHSA was completely inhibited by Tiron (1,2-dihydroxy-3,5-benzenedisulfonic acid) and superoxide dismutase. In contrast, catalase and mannitol had no effect. Our results indicate that in vitro glycoxidation of HSA induced a marked loss of antioxidant activity of this molecule to copper-mediated oxidation of LDL, which may be caused by the generation of superoxide.
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PMID:Contribution of superoxide to reduced antioxidant activity of glycoxidative serum albumin. 1243 98

Free oxygen radicals and insufficient antioxidant enzymes have been implicated in the pathogenesis of hypercholesterolemia (HC). Trace elements function as cofactors in antioxidant enzymes. Antioxidant system and trace elements were investigated in many different studies including HC, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in hypercholesterolemic patients given fluvastatin therapy. We examined malondialdehyde (MDA), copper zinc-superoxide dismutase (CuZn-SOD), and glutathione peroxidase (GSH-Px) activities together with copper (Cu), iron (Fe), and zinc (Zn) levels in erythrocytes of 35 patients with HC and 27 healthy control subjects. It was found that in patients with HC, erythrocyte MDA was significantly higher than those of controls and erythrocyte CuZn-SOD and GSH-Px activities were significantly lower in patients with HC. Erythrocyte iron levels were significantly higher than those of controls, and erythrocyte copper and zinc levels were significantly lower in patients with HC. Plasma lipid levels and the oxidative state were analyzed in statin-treatment groups given fluvastatin therapy before and after a 3-mo treatment period. In conclusion, we found that fluvastatin has significant antioxidant properties and these effects might be very important in managing dyslipidemia by improving endothelial function.
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PMID:Effects of statins on oxidative stress. 1507 10

A mutation of the CD36 gene that encodes a fatty acid transporter has been reported to play a role in insulin resistance in spontaneously hypertensive rat (SHR). Statins reduce circulating cholesterol and triglyceride concentrations. The objective of this study was to determine the role of CD36 and the significance of statin therapy in insulin-resistance syndromes. We determined the isometric relaxation induced by acetylcholine or lecithinized superoxide dismutase (SOD) in aortas obtained from Otsuka Long Evans Tokushima Fatty (OLETF) rats, a model of insulin resistance and dyslipidemia, and normal control (Long Evans Tokushima Otsuka; LETO) rats with or without cerivastatin treatment. We also determined the effect of cerivastatin on aortic expression of CD36 and PPARgamma. The CD36 genotype and microsatellite markers on chromosome 4 were also determined. The relaxation induced by acetylcholine and lecithinized SOD were attenuated in OLETF rats but restored by a low dose of cerivastatin without significant changes in serum cholesterol. These relaxations were also restored by a high dose of cerivastatin with significant reductions in serum cholesterol and triglyceride. Cerivastatin increased the aortic expression of CD36 and PPARgamma mRNA in both LETO and OLETF rats. However, the basal level of CD36 mRNA and the increase in CD36 mRNA in response to cerivastatin were significantly lower in OLETF rats than in LETO rats. Although the abnormal CD36 genotype reported in SHR was not found in OLETF rats, the microsatellite markers of D4Rat151 and D4Rat115 differed between OLETF and LETO rats. In conclusion, insulin resistance in OLETF rats may be partially due to an altered expression of CD36. Increased aortic expression of CD36 in response to cerivastatin could explain the reduction in serum triglyceride concentrations with statin therapy and may have pronounced beneficial effects in insulin-resistance syndromes.
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PMID:Effect of cerivastatin on endothelial dysfunction and aortic CD36 expression in diabetic hyperlipidemic rats. 1549 79

Insulin resistance and the consequent metabolic disorders are associated with a state of platelet hyperactivity. Oxidative stress is responsible for the persistent platelet activation. We sought to study the inhibitory effect of cardiotonic pills, an oral herbal component, on platelet function in a dog model with insulin resistance induced by high-fat feeding. We fed 18 dogs with a high-fat diet and six dogs with normal chow as control for 6 months. Then, six dogs were fed with a high-fat diet and received additional aspirin (250 mg/day), and another six dogs received additional cardiotonic pills (1,000 mg/day) for 4 months. Time-course changes in metabolic parameters and platelet function were detected. After high-fat feeding for 6 months, 18 dogs developed a series of metabolic disorders including obesity, dyslipidemia, oxidative stress and insulin resistance. In addition, a platelet hyperactivity state, characterized by increased agonist (arachidonic acid, ADP and collagen) induced platelet aggregation, platelet expression of adhesion molecules (P-selectin and GP IIb/IIIa), and platelet intracellular calcium concentration, was indicated. Cardiotonic pills showed a significant antioxidative activity by presenting an increase in plasma superoxide dismutase and decrease in erythrocyte glutathione, as well as a lipid-lowering effect (decrease in both plasma cholesterol and triglyceride). Either aspirin or cardiotonic pills could significantly reverse the platelet hypersensitivity and hyperfunction. Compared with aspirin, cardiotonic pills showed a more exaggerated inhibitory effect on platelet function (a significantly decreased collagen-stimulated platelet aggregation, and expression of adhesion molecules). In conclusion, cardiotonic pills inhibited platelet hyperfunction in dogs with insulin resistance. This inhibitory effect may mainly be explained by antioxidative activity and metabolic control.
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PMID:Inhibitory effects of cardiotonic pills on platelet function in dogs fed a high-fat diet. 1665 67

This study examined whether sucrose-rich diet (SRD)-induced hyperglycaemia, dyslipidemia and oxidative stress may be inhibited by N-acetylcysteine (C(5)H(9)-NO(3)S), an organosulfur from Allium plants. Male Wistar 40 rats were divided into four groups (n=10): (C) given standard chow and water; (N) receiving standard chow and 2 mg/l N-acetylcysteine in its drinking water; (SRD) given standard chow and 30% sucrose in its drinking water; and (SRD-N) receiving standard chow, 30% sucrose and N-acetylcysteine in its drinking water. After 30 days of treatment, SRD rats had obesity with increased abdominal circumference, hyperglycaemia, dyslipidemia and hepatic triacylglycerol accumulation. These adverse effects were associated with oxidative stress and depressed lipid degradation in hepatic tissue. The SRD adverse effects were not observed in SDR-N rats. N-Acetylcysteine reduced the oxidative stress, enhancing glutathione-peroxidase activity, and normalizing lipid hydroperoxyde, reduced glutathione and superoxide dismutase in hepatic tissue of SRD-N rats. The beta-hydroxyacyl coenzyme-A dehydrogenase and citrate-synthase activities were increased in SRD-N rats, indicating enhanced lipid degradation in hepatic tissue as compared to SRD. SRD-N rats had reduced serum oxidative stress and diminished glucose, triacylglycerol, very-low-density lipoprotein (VLDL), oxidized low-density lipoprotein (ox-LDL) and cholesterol/high-density lipoprotein (HDL) ratio in relation to SRD. In conclusion, NAC offers promising therapeutic values in prevention of dyslipidemic profile and alleviation of hyperglycaemia in high-sucrose intake condition by improving antioxidant defences. N-Acetylcysteine had also effects preventing metabolic shifting in hepatic tissue, thus enhancing fat degradation and reducing body weight gain in conditions of excess sucrose intake. The application of this agent in food system via exogenous addition may be feasible and beneficial for antioxidant protection.
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PMID:Effects of N-acetylcysteine on sucrose-rich diet-induced hyperglycaemia, dyslipidemia and oxidative stress in rats. 1681 77

Dyslipidemia increases the risks for atherosclerosis in part by impairing endothelial integrity; endothelial progenitor cells (EPCs) play a pivotal role in reendothelialization. In this study, we investigated the mechanism whereby oxidized low-density lipoprotein (oxLDL) affects the function of differentiated EPCs (EDCs). In EDCs expanded in vitro from EPCs isolated from human cord blood, we measured EDC responses to both copper-oxidized LDL and L5, an electronegative LDL minimally oxidized in vivo in patients with hypercholesterolemia. OxLDL induced apoptosis of EDCs and impaired their response to nitric oxide. We found that the key to oxLDL-induced apoptosis in both EDCs and endothelial cells is the induction of a conformational change of Bax, leading to Bax activation without altering its expression. The conformationally changed Bax translocated to the mitochondria and stimulated apoptosis, as Bax knockdown prevented oxLDL-induced apoptosis in EDCs. The activation of Bax is mediated by an increase in p53 and knockdown of p53 abolished oxLDL-induced activation of Bax and apoptosis. OxLDL activated p53 through production of mitochondria-derived reactive oxygen species. In EDCs treated with a recombinant adenovirus expressing superoxide dismutase or N-acetyl-cysteine (but not catalase), the p53-Bax pathway activated by oxLDL was blocked, and apoptosis was prevented. Of importance, treatment of EDC with low-concentration L5 stimulated superoxide dismutase expression, which significantly attenuated apoptosis in EDCs exposed to high-concentration L5. These findings suggest that exposure of EDCs and endothelial cells to either experimentally prepared or naturally occurring modified LDL results in an increased transfer of mitochondria-derived superoxide anion to p53, which stimulates a conformational change in Bax favoring its translocation to the mitochondria with resultant apoptosis of these cells.
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PMID:Oxidized low-density lipoprotein stimulates p53-dependent activation of proapoptotic Bax leading to apoptosis of differentiated endothelial progenitor cells. 1728 42

Diabetes mellitus has assumed epidemic proportions in most parts of the world, and it is a major source of morbidity in developed countries. In addition, in several instances, diabetes is associated with a variety of metabolic abnormalities, including abdominal obesity, insulin resistance, hypertension, dyslipidemia, and hyperglycemia. There is considerable evidence that hyperglycemia causes the generation of reactive oxygen species (ROS), ultimately leading to increased oxidative stress in a variety of tissues. In the absence of an appropriate compensatory response by the endogenous antioxidants, such as vitamins C and E, catalase, glutathione, and superoxide dismutase, oxidative stress dominates, resulting in the activation of stress-sensitive intracellular signaling pathways. One of the major consequences is the generation of gene products that cause cellular damage and are ultimately responsible for the late complications of diabetes. The ability of antioxidants to protect against the effects of hyperglycemia in vitro, along with the clinical benefits often reported following antioxidant therapy, supports a causative role of oxidative stress in mediating and/or worsening these abnormalities. This review will focus on the critical assessment of the literature as it relates to the association between oxidative stress and diabetes, followed by the role of oxidative stress in the complications of type 2 diabetes mellitus. Finally, a review of the use of the antioxidant vitamin E will be provided in diabetic patients by assessing and evaluating some of the clinical trials in the literature.
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PMID:The use of vitamin E in type 2 diabetes mellitus. 1749 41

Oxidative stress has been proposed as the pathogenic mechanism linking insulin resistance with endothelial dysfunction during diabetes. The present study investigated the attenuation of plasma dyslipidemia and oxidative damage by caloric restriction in experimental diabetes. Forty male Wistar rats were divided into ad libitum and calorie-restricted groups. The calorie-restricted group was subjected to 30% caloric restriction for 63 days before induction of diabetes to 50% of both groups. Caloric restriction significantly (p<0.01) reduced the body weights, reactive oxygen species (ROS), catalase, total cholesterol levels and non-significantly reduced SOD activities in non-diabetic and diabetic rats. Caloric restriction was also found to improve blood glucose levels, glycated hemoglobin, malondialdehyde, triglyceride, oxidized glutathione and reduced glutathione levels and significantly (p<0.05) increased GPx and GR activities in the experimental animals. The non-diabetic rats fed ad libitum had the most significant increases in body weight which could be due to dyslipidemia. These results indicate that dietary caloric restriction attenuates the oxidative damage and dyslipidemia exacerbated during diabetes as evidenced by the significant reduction in their body weights, ROS, total cholesterol levels and the increases in GPx activity and redox status.
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PMID:Attenuation of plasma dyslipidemia and oxidative damage by dietary caloric restriction in streptozotocin-induced diabetic rats. 1758 83

The aim of present study--comparative characteristic of captopril and of losartan action on the oxidative metabolism in experimental hyperlipidemia. Experiments carried out on rabbits,which were divided into three groups(ten animal in each group) and orally receiving during 45 days: I control group (cholesterol 500mg/kg + methylthiouracil 100mg/kg, II group-captopril 5 mg/kg + cholesterol 500mg/kg + methylthiouracil 100mg/kg, III group-losartan 8mg/kg + cholesterol-500mg/kg + methylthiouracil 100mg/kg. Activity of superoxide dismutase, catalase, level of malonic dialdehyde, osmotic resistance of erythrocytes and resistanse of LDL to oxidation and concentration of nitric oxide in the blood have been evaluated . The administration of captopril and losartan in experimental hyperlipidemia eqivalently increased activity of SOD and catalase, osmotic resistance of erythrocytes and resistanse of LDL to oxidation, whereas decreased content of malonic dialdehyde compared to the control group . Captopril was more effective than losartan in preserving of nitric oxide. We conclude that captopril and losartan inhibited oxidative stress, which are probably associated with the inhibition of angiotensin 11. Captopril and losartan are safely used in patients during cardio-vascular disease with dyslipidemia.
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PMID:[Comparative characteristic of angiotensin-converting enzyme inhibitor--captopril and the angiotensin II receptor blokers--losartan action on the oxidative metabolism in experimental hyperlipidemia in rabbits]. 1798 66

To study the effects of diclofenac, a nonselective nonsteroidal anti-inflammatory drug (NSAID), on lipid profile, oxidized low-density-lipoprotein (Ox-LDL), serum antioxidant defenses and markers of oxidative stress, male Wistar rats were divided into two groups (n=10): (C) receiving intramuscularly a single daily dose of saline (NaCl 0.9%), and (AI) receiving intramuscularly a single daily dose of 10 mg/kg diclofenac sodium (C14H10Cl2NNaO2). After 28 days diclofenac-treated rats had lower Ox-LDL, apoprotein B (apo-B), apo-B/LDL-cholesterol and lipid hydroperoxide than C. Total antioxidant substances and superoxide dismutase were increased in diclofenac-treated rats, while no significant changes were observed in catalase, glutathione peroxidase and nitric oxide. A perincubation test done to examine the possibility of mechanism-based activation showed that diclofenac had no effect on maximal superoxide dismutase velocity, but significantly reduced the Michaelis-Menten (KM) constant, indicating that diclofenac induced SOD activation increasing substrate linkage affinity to the enzyme-catalytic site. In conclusion, diclofenac had beneficial effects decreasing Ox-LDL and improving antioxidant defense. It appears that the application of this agent may be feasible and beneficial for serum antioxidant protection, which certainly would bring new insights on dyslipidemia control.
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PMID:Beneficial effects of diclofenac therapy on serum lipids, oxidized low-density lipoprotein and antioxidant defenses in rats. 1834 92


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