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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidative damage due to free radical production is increased in uraemic patients and has been suggested as a possible factor contributing to the anaemia of chronic renal failure (CRF) and the pathogenesis of atherosclerosis. Oxidative stress was assessed in 40 patients with CRF maintained by either haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD) and in 18 healthy controls. Lipid peroxidation (assessed as malondialdehyde, MDA), total glutathione (TG), antioxidant enzyme (glutathione reductase (GSHRx), glutathione peroxidase (GSHPx) and superoxide dismutase (SOD)) activity and antioxidant associated trace metal (selenium, copper, zinc) levels were studied. Erythrocyte membrane fluidity was examined using the fluorescent probe 1,6 diphenyl-1,3,5-hexatriene (DPH). The results indicate increased levels of oxidative stress and altered erythrocyte membrane fluidity in patients treated with CAPD compared with controls and patients treated with HD. Only minor changes were observed in patients treated with HD. Altered free radical activity, oxidative stress and altered erythrocyte membrane fluidity observed in patients with CRF may contribute to the increase in vascular disease in such patients and to the anaemia of CRF.
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PMID:Oxidative stress and erythrocyte membrane fluidity in patients undergoing regular dialysis. 755 72

The relationship between antioxidants and endothelial cell injury was examined in 119 patients with (n = 48) or without (n = 71) vascular disease who were attending a hyperlipidaemia clinic. Serum levels of total antioxidant capacity, glutathione peroxidase (a protein antioxidant), von Willebrand factor (vWf, a specific endothelial cell product and marker of injury) and routine lipids were measured in the patients and from 58 healthy controls. Compared to controls, total antioxidant capacity (P < 0.01) and glutathione peroxidase (P < 0.0001) were lower whilst vWf was higher (P < 0.0001) amongst the patients. Comparing patients with and without vascular disease, glutathione peroxidase was lower (P < 0.03) and vWf was higher (P < 0.05) in the presence of vascular disease but there was no difference in levels of serum lipids or total antioxidant capacity. vWf and glutathione peroxidase were inversely correlated (r = -0.26, P < 0.005). We conclude that patients with hypercholesterolaemia have reduced antioxidant capacity and this is most severe in patients with clinically apparent vascular disease. This, linked to the finding of increased vWf in hypercholesterolaemia with highest levels in those patients with vascular disease, suggests that loss of antioxidant capacity may expose the vascular endothelium to excess oxidative damage. These results suggest a link between hypercholesterolaemia, impaired ability to resist free radical attack, and the development of atherosclerosis.
Atherosclerosis 1995 Aug
PMID:Antioxidants, von Willebrand factor and endothelial cell injury in hypercholesterolaemia and vascular disease. 757 74

Methionine is converted by the transmethylation/transsulfuration pathway to homocysteine which may exert atherogenic effects by several mechanisms, including lipid peroxidation. Therefore, the excessive dietary methionine may induce the development of atherosclerosis. To test this hypothesis, plasma and aortic thiobarbituric acid reactive substances (TBARS), as well as activities of aortic and erythrocyte superoxide dismutase (SOD), catalase and selenium-dependent glutathione peroxidase (GPX) were measured in rabbits fed a diet enriched with 0.3% methionine for 6 or 9 months. Histological examinations of aortas also were performed. Feeding rabbits a methionine-enriched diet for 6 or 9 months resulted in significant increases in plasma and aortic TBARS levels and aortic antioxidant enzyme activities. However, a decrease in plasma antioxidant activity (AOA) was observed. In erythrocytes, SOD activity increased, catalase remained normal and GPX decreased in the treated animals. Histological examination of aortas showed typical atherosclerotic changes, such as intimal thickening, deposition of cholesterol, and calcification in methionine-fed rabbits. These results confirm that high-methionine diet may induce atherosclerosis in rabbits and indicate disturbances in lipid peroxidation and antioxidant processes as possible mechanisms of its atherogenic influence.
Atherosclerosis 1995 Jun
PMID:Increased lipid peroxidation as a mechanism of methionine-induced atherosclerosis in rabbits. 766 80

This review briefly summarizes the scientific evidence for a possible role of antioxidants in the prevention of coronary heart disease (CHD). Antioxidants in our diet include vitamins E, C, and beta-carotene, whereas selenium is an integral part of the antioxidant enzyme glutathione peroxidase (GSHPx). Experimental evidence suggests that free-radical damage and antioxidant defence may play an important role in the development of coronary heart disease. Epidemiological studies have produced some intriguing results, but have not indicated unequivocally that a high intake of antioxidants leads to a decreased cardiovascular disease risk. We conclude that the antioxidant atherosclerosis hypothesis is promising, but that the results of long-term intervention studies are still to be awaited. Preventive action based on antioxidant supplementation is therefore not justifiable as yet. Nevertheless, the findings so far certainly do support the recommendations for a varied diet rich in vegetables and fruit.
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PMID:Antioxidants and coronary heart disease. 769 69

Selected parameters of lipid metabolism (cholesterol, HDL cholesterol, LDL cholesterol, atherogenic index, triacylglycerols, vitamin C, vitamin E, vitamin E/cholesterol, plasma fatty acid profile) and pro-oxidative/anti-oxidative parameters (conjugated dienes of fatty acids, activity of catalase and glutathione peroxidase) were estimated in blood of 59 healthy vegetarians aged 19-30 years. When compared to non-vegetarians, no incidence of obesity, low levels of cholesterol, LDL cholesterol, atherogenic index or triacylglycerols, HDL cholesterol levels on the margin of 1.4 mmol/l (boundary level between standard and reduced risk) as well as a higher plasma content of polyunsaturated fatty acids and a higher 18:2/18:1 ratio were all favourable consequences of vegetarianism with respect to atherosclerosis prevention. These factors are completed by higher levels of protective compounds with antisclerotic activity (vitamin C, vitamin E/cholesterol--protecting LDL from lipoperoxidation) as well as by beneficial pro-oxidative/anti-oxidative parameters (low values of conjugated dienes, significantly higher activity of catalase, higher level of vitamin C).
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PMID:Selected parameters of lipid metabolism in young vegetarians. 770 61

Patients with chronic renal failure, including those receiving regular long-term haemodialysis, have a high incidence of premature cardiovascular disease. Oxidative stress, which occurs when there is excessive free-radical production or low antioxidant levels, has recently been implicated as a causative factor in atherogenesis. The aim of this study was to determine if chronic renal failure and haemodialysis were associated with increased oxidative stress. Serum malondialdehyde was measured as a marker of lipid peroxidation in 15 patients with conservatively managed chronic renal failure (CRF), 15 patients with CRF undergoing regular haemodialysis and 15 healthy controls. Selenium, glutathione peroxidase and antioxidant vitamins were also measured. Malondialdehyde was elevated in dialysis patients in comparison to CRF and control groups (dialysis 1.16 +/- 0.08 mumol/l, CRF 0.94 +/- 0.07, controls 0.66 +/- 0.10). Antioxidants, including vitamin C, selenium and glutathione peroxidase, were decreased in dialysis patients and to a lesser extent in the CRF group (vitamin C-dialysis 16.43 +/- 3.76 mumol/l, CRF 34.5 +/- 8.6, controls 56.11 +/- 7.41; selenium-dialysis 0.77 +/- 0.07 mumol/l, CRF 0.69 +/- 0.06, controls 1.09 +/- 0.06: glutathione peroxidase-dialysis 101 +/- 5 U/l, CRF 160 +/- 11, controls 290 +/- 10). These findings indicate oxidative stress in patients with CRF which is further exacerbated by haemodialysis, as evidenced by increased lipid peroxidation and low antioxidant levels. This stress may play a role in the development of atherosclerosis in these groups.
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PMID:Oxidative stress in haemodialysis. 782 May 42

Selenium (Se) is an essential component of glutathione peroxidase (GSH-Px), an enzyme that protects cells by reducing intracellular peroxides. Impaired Se status and GSH-Px activity seem associated with increased risk of atherosclerotic vascular diseases. This study reports the effects of Se supplementation on GSH-Px activity, on prostacyclin (PGI2) production, on 12-hydroxy-eicosatetraenoic acid (12-HETE) levels, and on GSH-Px mRNA expression in cultured human umbilical vein endothelial cells (HUVEC). Se-enriched HUVEC showed significant increase of both GSH-Px activity and thrombin-stimulated production of PGI2 in the presence of stable concentrations of 12-HETE. On the other hand, an inverse correlation between Se concentrations in culture media and GSH-Px mRNA levels in Northern blot analysis was shown; this suggests that a major degree of regulation for GSH-Px expression by Se is most likely exerted at the posttranscriptional level. These observations may help to explain the increased incidence of atherosclerosis described in Se-deficient individuals.
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PMID:Selenium enhances glutathione peroxidase activity and prostacyclin release in cultured human endothelial cells. Concurrent effects on mRNA levels. 788 76

In the present study possible antiatherogenic effects of dietary garlic were investigated in an experimental model which consists in the deendothelialisation by ballooning of the a. carotis communis of rats. 3 experimental groups were established: group I received a standard diet; the diet of group II was supplemented with 2% cholesterol and group III received 2% cholesterol and 5% dried garlic powder. Four weeks after ballooning plasma cholesterol, the average thickness of the neointima as well as the DNA content and the expression of collagens type I, III and IV in the ballooned arterial segment were determined. Furthermore, the specific activities of the enzymes glutathione peroxidase, glutathione disulfide reductase, glutathione-S-transferase and glucose 6 phosphate dehydrogenase were measured in homogenates of liver, heart and aorta. Hypercholesterolemia induced by cholesterol-feeding (group II 92 +/- 18 mg/100 ml) was significantly reduced by garlic (group III 53 +/- 19 mg/100 ml). Only little effects of garlic were seen in inhibiting neointima after ballooning. However, significant effects were found in protecting the enzymes of the glutathione dependent peroxide detoxification system, which is strongly impaired under hypercholesterolemia. Generally a normalisation, in some cases even an improvement beyond that, of the enzyme activities occurred in the garlic treated group. This indicates that in the model of atherosclerosis used here garlic is effective in lowering plasma cholesterol and in improving peroxide detoxification, however, it has only little influence on the wound healing reaction and does not significantly inhibit the development of intimal thickenings after ballooning.
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PMID:Effects of dietary garlic supplementation in a rat model of atherosclerosis. 802 33

61 spa patients, predominantly with heart and vascular diseases, were divided into 2 therapeutic groups. In addition to the usual balneotherapeutic program, one group (J) received a course of "iodine brine concentrate" for drinking (2 x 100 ml, daily iodine uptake approximately 9 mg), and the control group (CI) received isotonic NaCl in the same way. The patients were mostly on a reduced-fat and -calorie diet. The following parameters were determined at the beginning and at the end of the 26-day treatment period: total cholesterol, HDL-cholesterol, triglycerides, lipoprotein (a) (in serum); selenium (Se), malondialdehyde (MDA), and activities of Se-dependent, Se-independent, and total glutathione peroxidase (GSH-PX) (in plasma). In the J group, a significant increase was found in Se-independent (+17%) and total GSH-PX (+5%) and a significant decrease in total cholesterol (-6.9%) and MDA (-13.2%). At the end of the cure, Se levels were higher in the J group than in the C1 group. The only significant change in the C1 group was a decrease in HDL-cholesterol. Positive correlations were found between selenium and Se-dependent GSH-PX (r = 0.253) and between total GSH-PX and Se-dependent GSH-PX (r = 0.665). A negative correlation was obtained between Se-dependent and Se-independent GSH-PX (r = -0.331). The results are discussed with regard to the importance of antioxidant defense mechanisms in several degenerative diseases (atherosclerosis, diabetes, cataract etc.), and also respecting interactions between iodine and selenium metabolism, as well as normalization effects conditioned by the balneotherapy itself.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Changes in selenium status, antioxidant enzyme activity and lipid peroxide level after drinking cures in Bad Hall health resort]. 814 96

Lipid parameters (cholesterol CH, HDL-, LDL-cholesterol, triacylglycerols TG, atherogenic index AI) were estimated in four age groups of vegetarians, 82 males and 80 females, aged 15 to 60 years. The period of consumption of vegetarian food was 1.4 to 1.9 years for adolescents (15-18 years old) or 2.4 to 5.4 years for adults (age groups 19-29 years, 30-39 years and 40-60 years). Lacto-vegetarians constituted one half of females and one third of males. Vitamin C content, lipid peroxidation levels (conjugated dienes, CD) and the activities of catalase (CAT) and glutathione peroxidase (GSH-Px) were estimated in the oldest age group of males and females. Low levels of TG and glutathione peroxidase (GSH-Px) were estimated in the oldest age group of males and females. Low levels of TG and CH (in the lower half of the reference range), low calculated values of LDL-CH and AI, as well as values of HDL-CH in the upper region of the standard risk zone or over 1.4 mmol/l (reduced risk level) in males and females of all age groups are the positive factors of vegetarian nutrition in prevention of atherosclerosis. High levels of vitamin C in blood, absence of obesity and low blood pressure should be mentioned here as additional positive factors as well. When considered as a single isolated factor, the nearly significantly elevated values of CD (linked to increased intake of unsaturated fatty acids) could be a negative factor of vegetarian nutrition.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipid parameters in blood of vegetarians. 814 53


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