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

The biological effects of reactive oxygen species and other radicals controlled by antioxidant mechanisms are modified by various enzymes and other substrates. Antioxidant substrates are divided into those with lipophilic and hydrophilic groups. Retinol and tocopherol are the main representations of lipophilic antioxidants. The aim of the present study was to describe the changes of retinol and alpha-tocopherol which occurred in hemodialysis (HD) patients in respect to the influence of antioxidant systems. The experimental group consisted of 14 patients on regular HD treatment. The control group consisted of 14 healthy blood donors. HPLC was used to measure retinol and alpha-tocopherol in serum. We found that the retinol concentration was significantly higher in HD patients compared to controls (2.35 +/- 0.95 versus 0.90 +/- 0.23 mg/L, p < 0.0001). The concentration of alpha-tocopherol in serum was not different in both study groups (7.32 +/- 3.01 versus. 8.94 +/- 3.57 mg/L). A review of the MEDLINE database since 1985 found a few references concerning these important antioxidant vitamins in HD patients and these contained contrasting results. It has been suggested that some of the complications related to HD including cardiovascular complications, anemia and atherosclerosis may be due to ineffective antioxidant systems and/or to increased free oxygen radical production. The question about supplementation of antioxidants in HD patients is open although there are some positive data regarding the use of moderate and safe selenium supplementation in HD patients. HD patients treated by erythropoietin had increased plasma concentration of retinol and normal level of alpha-tocopherol compared to healthy group. However, this positive finding did not affect lipid peroxidation, which is increased in HD patients and leads to some complications during HD treatment.
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PMID:Retinol and alpha-tocopherol in hemodialysis patients. 960 38

To investigate how cigarette smoking increases the risk of cardiovascular disease, risk factors were compared between 166 cigarette smokers and 312 non-smokers, in a random sample of males (Chinese, Malays and Asian Indians) aged 30-69 years from the general population of Singapore. There was adjusted for age and ethnic group. The prevalence of hypertension was lower in cigarette smokers (15.2%) than non-smokers (21.9%), with the difference reduced by adjustment for body mass index (BMI). Smokers had: lower mean serum HDL-cholesterol (0.76 versus 0.81 mmol/l) and higher mean serum fasting triglyceride (1.92 versus 1.71 mmol/l), which will increase atherosclerosis; higher mean plasma fibrinogen (2.75 versus 2.67 g/l) and plasminogen activator inhibitor 1 [PAI-1] (24.9 versus 22.2 ng/ml), which will increase thrombosis; and lower mean plasma vitamin C (4.4 versus 6.4 mg/l) and serum selenium (118 versus 123 microg/l), which may increase atherosclerosis. Adjustment for BMI slightly increased the differences for HDL-cholesterol, fasting triglyceride, fibrinogen and PAI-1, indicating that less generalised obesity among smokers reduces their increased cardiovascular disease risk. Smoking was not found to be related to: diabetes mellitus; serum total cholesterol, LDL-cholesterol, apolipoproteins A1 and B and lipoprotein(a); plasma factor VIIc and prothrombin fragment 1 + 2; and plasma vitamins A and E and serum ferritin. There was no evidence of increased insulin resistance in smokers, as measured by mean fasting serum insulin.
Atherosclerosis 1998 Apr
PMID:Cardiovascular risk factors in relation to cigarette smoking: a population-based survey among Asians in Singapore. 962 68

Male Sprague Dawley rats were divided into three groups, viz (I) Controls, (II) High fat diet (HFD) fed, (III) HFD fed+selenium supplemented. After three months of treatment, there were significant increases in serum cholesterol and triglycerides in HFD fed group as compared to control. However, in Se supplemented group, the levels of serum cholesterol and triglycerides were significantly less as compared to group II. Selenium-dependent glutathione peroxidase (GSH-Px) activity in the liver and the aorta increased significantly in HFD fed animals and also showed additional significant increase on selenium supplementation. Malonyldialdehyde (MDA) concentrations in serum, liver and aorta and the activity of nitric oxide synthase (NOS; evident from reactive nitrogen intermediates and citrulline levels) in plasma showed significant increases in HFD fed group. However, supplementation of selenium led to a significant reduction in the levels of these parameters vis-a-vis HFD fed animals except in MDA levels in the serum and the liver where this decrease was non-significant. The important finding of this study is that selenium supplementation modulates the sequences favoring pathogenesis of atherosclerosis.
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PMID:Selenium supplementation and diet induced hypercholesterolemia in the rat: changes in lipid levels, malonyldialdehyde production and the nitric oxide synthase activity. 967 57

Several antioxidants inhibit atherosclerosis. This study investigated the hypothesis that combining vitamin E, a lipophilic antioxidant, with vitamin C, a hydrophilic antioxidant, and/or selenium, a cofactor of peroxidases that detoxify lipid peroxides, would inhibit atherosclerosis more effectively than vitamin E alone. We also considered whether regional variation in inhibition of atherosclerosis by antioxidants would be associated with regional variation in aortic lipophilic antioxidants. Rabbits were fed an atherogenic diet (control) or an atherogenic diet supplemented with vitamin E, vitamins E and C, vitamin E+selenium, vitamins E and C+selenium, or probucol (positive control). Supplements were as follows: vitamin E, 146 IU/d; vitamin C, 791 mg/d; selenium, 22 microg/d; or probucol, 406 mg/d. Vitamin C did not influence atherosclerosis. After 22 weeks of treatment, rank order of aortic atherosclerosis was control>vitamin E (with or without vitamin C)>vitamin E+selenium (with or without vitamin C)>probucol. Antioxidant treatment reduced aortic cholesterol concentrations 21% to 56%, 29% to 86%, and 19% to 75% for the aortic arch, descending thoracic aorta, and abdominal aorta, respectively (P<0.025 to P<0.0003 by ANOVA), with slightly greatly reductions for areas of atherosclerotic lesions. Some treatments reduced plasma cholesterol concentrations, but none altered the distribution of cholesterol among lipoproteins. Corrected for differences in plasma cholesterol concentrations, aortic cholesterol concentrations were reduced up to 72% (P<0.02) by the antioxidant treatments, with equal reductions by vitamin E+selenium and by probucol. Aortic alpha-tocopherol standardized by aortic cholesterol as a measure of aortic lipids was lower in the abdominal aorta than in the aortic arch of rabbits not given alpha-tocopherol and increased relatively more in the abdominal aorta than in the aortic arch with alpha-tocopherol supplementation. The results of this study suggest that vitamin E+ selenium inhibited atherosclerosis as effectively as an equally hypocholesterolemic dose of probucol by a mechanism(s) that is in part independent of effects on plasma and lipoprotein cholesterol concentrations. The tendency for greater efficacy of antioxidant treatments in the abdominal aorta than aortic arch may relate to the lower concentrations of alpha-tocopherol in the abdominal aorta of unsupplemented rabbits.
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PMID:Vitamin E combined with selenium inhibits atherosclerosis in hypercholesterolemic rabbits independently of effects on plasma cholesterol concentrations. 972 93

Oxidation of low density lipoprotein is involved in the pathogenesis of atherosclerosis. Epidemiological studies suggest a negative correlation between the occurrence of cardiovascular diseases and blood concentrations of lipophilic antioxidants such as vitamin A and E and beta-carotene. Trace elements such as selenium, zinc and copper are involved in the activity of antioxidant enzymes: glutathione peroxidase and superoxide dismutase. The aim of this work was to determine the antioxidant and trace elements status of patients with very severe hypercholesterolemia and who were treated by dextran sulphate low density lipoprotein apheresis, in comparison with two control populations: one constituted by normocholesterolemic subjects and the other by hypercholesterolemic patients before treatment. Our results showed that, as compared with normocholesterolemic subjects, patients treated by LDL-apheresis were not deficient in vitamin E, beta-carotene and copper but had low plasma levels of selenium, zinc and vitamin A. The low selenium and vitamin A levels were due to the treatment by LDL-apheresis by itself, while the hypercholesterolemia of these patients might have provoked the low plasma levels of zinc. This study pointed out the interest of a supplement of selenium, zinc and vitamin A in patients treated by LDL-apheresis.
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PMID:[The plasma antioxidant status and trace elements in patients with familial hypercholesterolemia treated with LDL-apheresis]. 977 31

Patients infected with HIV are at increased risk of atherosclerosis, and have evidence of endothelium dysfunction. The hypothesis was tested that HIV-related endothelium dysfunction is related to loss of antioxidants. This was done by the supplementation of the antioxidants selenium and beta-carotene. We supplemented the diet of 10 HIV-seropositive subjects with 100 microg selenium daily, 11 subjects with 30 mg beta-carotene twice daily while 15 subjects were not supplemented. Plasma was obtained at outset and after a year, and tested by ELISA for endothelial cell, platelet and inflammatory markers. The non-supplemented patients experienced increases in von Willebrand factor and soluble thrombomodulin (both p <0.01). There were no changes in any of the indices in the patients taking selenium or beta-carotene. Increased von Willebrand factor and soluble thrombomodulin in the non-supplemented patients imply increased damage to the endothelium over the year of the study. Therefore we interpret the lack of increase in the patients taking antioxidants as evidence of the protection of the endothelium by these agents.
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PMID:Effect of the antioxidants selenium and beta-carotene on HIV-related endothelium dysfunction. 986 76

Greenlanders (Eskimos) have low prevalence of ischaemic heart disease, partly explained by a lower extent of atherosclerosis and a low n-6/n-3 ratio of polyunsaturated fatty acids. As atherosclerosis is also a result of oxidative stress, the total antioxidative readiness could have a substantial impact. From a health survey we chose the subpopulation from the most remote area, where the traditional Greenlandic diet with high intake of sea mammals and fish predominates. The mean (SD) of S-CoQ10 in males was 1.495 (0.529) nmol/ml and 1.421 (0.629) nmol/ml in females, significantly higher (p < 0.001) compared to a Danish population. In a linear multiple regression model the S-CoQ10 level is significantly positively associated with age and S-selenium in males, and S-total cholesterol in females. The high level of CoQ10 in Greenlanders probably reflects diet, since no bioaccumulation takes place, and it could probably be a substantial part of the antioxidative defense.
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PMID:High serum coenzyme Q10, positively correlated with age, selenium and cholesterol, in Inuit of Greenland. A pilot study. 1041 47

Thanks to progress in zinc research, it is now possible to describe in more detail how zinc ions (Zn++) and nitrogen monoxide (NO), together with glutathione (GSH) and its oxidized form, GSSG, help to regulate immune responses to antigens. NO appears to be able to liberate Zn++ from metallothionein (MT), an intracellular storage molecule for metal ions such as zinc (Zn++) and copper (Cu++). Both Zn++ and Cu++ show a concentration-dependent inactivation of a protease essential for the proliferation of the AIDS virus HIV-1, while zinc can help prevent diabetes complications through its intracellular activation of the enzyme sorbitol dehydrogenase (SDH). A Zn++ deficiency can lead to a premature transition from efficient Th1-dependent cellular antiviral immune functions to Th2-dependent humoral immune functions. Deficiencies of Zn++, NO and/or GSH shift the Th1/Th2 balance towards Th2, as do deficiencies of any of the essential nutrients (ENs) - a group that includes methionine, cysteine, arginine, vitamins A, B, C and E, zinc and selenium (Se) - because these are necessary for the synthesis and maintenance of sufficient amounts of GSH, MT and NO. Via the Th1/Th2 balance, Zn++, NO, MT and GSH collectively determine the progress and outcome of many diseases. Disregulation of the Th1/Th2 balance is responsible for autoimmune disorders such as diabetes mellitus. Under Th2, levels of interleukin-4 (II-4), II-6, II-10, leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) are raised, while levels of II-2, Zn++, NO and other substances are lowered. This makes things easier for viruses like HIV-1 which multiply in Th2 cells but rarely, if ever, in Th1 cells. AIDS viruses (HIVs) enter immune cells with the aid of the CD4 cell surface receptor in combination with a number of co-receptors which include CCR3, CCR5 and CXCR4. Remarkably, the cell surface receptor for LTB4 (BLTR) also seems to act as a co-receptor for CD4, which helps HIVs to infect immune cells. The Th2 cytokine II-4 increases the number of CXCR4 and BLTR co-receptors, as a result of which, under Th2, the HIV strains that infect immune cells are precisely those that are best able to accelerate the AIDS disease process. The II-4 released under Th2 therefore not only promotes the production of more HIVs and the rate at which they infect immune cells, it also stimulates selection for the more virulent strains. Zn++ inhibit LTB4 production and numbers of LTB4 receptors (BLTRs) in a concentration-dependent way. Zn++ help cells to keep their LTB4 'doors' shut against the more virulent strains of HIV. Moreover, a sufficiency of Zn++ and NO prevents a shift of the Th1/Th2 balance towards Th2 and thereby slows the proliferation of HIV, which it also does by inactivating the HIV protease. Research makes it look likely that deficiencies of ENs such as zinc promote the proliferation of Th2 cells at the expense of Th1 cells. Zinc deficiency also promotes cancer. Under the influence of Th1 cells, zinc inhibits the growth of tumours by activating the endogenous tumour-suppressor endostatin, which inhibits angiogenesis. The modern Western diet, with its excess of refined products such as sugar, alcohol and fats, often contains, per calorie, a deficiency of ENs such as zinc, selenium and vitamins A, B, C and E, which results in disturbed immune functions, a shifted Th1/Th2 balance, chronic (viral) infections, obesity, atherosclerosis, autoimmunity, allergies and cancer. In view of this, an optimization of dietary composition would seem to give the best chance of beating (viral) epidemics and common (chronic) diseases at a realistic price.
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PMID:Modern diets and diseases: NO-zinc balance. Under Th1, zinc and nitrogen monoxide (NO) collectively protect against viruses, AIDS, autoimmunity, diabetes, allergies, asthma, infectious diseases, atherosclerosis and cancer. 1049 17

Elevated plasma free radical concentration (expression of enhanced oxidative stress) is related to different pathophysiological conditions such as ageing, cancer and diabetes. Nevertheless, even in healthy subjects a rise in plasma free radicals is due to hyperglycaemia, elevated free fatty acids and hyperinsulinaemia. Once elevated oxidative stress occurs, accelerated atherosclerosis may be present. Thus, antioxidants might potentially be useful in preventing or delaying the development of atherosclerosis. Several epidemiological studies have provided conflicting results, whereas interventional studies have demonstrated that antioxidant administration at pharmacological doses is useful for secondary prevention of atherosclerosis. The role of antioxidants in diabetic patients is still debatable, and it is too early to suggest this means for the prevention of atherosclerosis. Concerning trace elements, several studies have indicated that iron, copper, zinc and selenium may play a role in the pathogenesis of atherosclerosis. Nevertheless, only future longitudinal studies can provide a final response. In conclusion, the whole body of studies to date clearly demonstrates that antioxidants may be useful for secondary prevention of coronary heart disease.
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PMID:Primary and secondary prevention of atherosclerosis: is there a role for antioxidants? 1056 18

After a short review of the data on the free radicals occurring in the human body (hydroxyl radical, superoxide, nitric acid, peroxynitrite), the possible effects of these radical upon the cardiovascular system are presented. The preservation of the oxidants-antioxidants balance is highly important for preventing the cardiovascular diseases. Endogenous antioxidants are not 100 per cent effective, reason why for the individuals with atherosclerosis and ischemic heart disease antioxidant supplements (tocopherols, carotenes, vitamin C, selenium) are essential especially during the seasons when diets are deficient in fruits and vegetables.
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PMID:[Oxidative stress and antioxidants in the diet in pathological processes at the level of the cardiovascular system]. 1075 83


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