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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin E in conventional therapeutic doses (400 mg/day) was given to 17 patients with hyperlipidemia on long-term treatment with diets enriched in polyunsaturated fatty acids and with clofibrate. The effect of this treatment on total serum cholesterol and on serum triglycerides was studied. To avoid influences of other factors (especially changes in dietary habits) the investigation was performed giving the patients tocopherol and placebo randomly, double blind and cross-over. No significant effect of vitamin E on total serum cholesterol or on serum triglycerides was seen.
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PMID:Effect of vitamin E on serum cholesterol and triglycerides in hyperlipidemic patients treated with diet and clofibrate. 20 60

Vitamin E deficiency in two species of monkeys (capuchins and cynamolgus) reduced the in vitro cholesterol esterification by plasma lecithin-cholesterol acyltransferase. The reduction was greates in the most deficient species and in animals fed a diet rich in polyunsaturated fat (safflower oil) stripped of vitamin E. The best correlate of total esterification was the plasma concentration of free cholesterol which reflected the degree of hyperlipidemia, found to be greatest in capuchins fed coconut oil. A logical explanation for the decreased LCAT activity in vitamin E deficiency would be peroxidative damage of substrate (the PUFA of lecithin) or of sulfhydryl sited on lecithin-cholesterol acyltransferase itself. However, neither case was fully supported by the data suggesting that additional information concerning the nature of the reaction and the role of vitamin E is required.
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PMID:Depression of lecithin-cholesterol acyltransferase esterification in vitamin E-deficient monkeys. 80 56

Experiments were designed to determine how varying levels of plasma lipids affect tissue deposition of alpha-tocopherol (vitamin E). Hypolipemia was induced by feeding orotic acid, and hyperlipemia was obtained using genetically obese rats. With equal dietary intakes of alpha-tocopherol, hypolipemic rats had lower plasma and tissue concentrations than rats with normal plasma lipids. An exception was liver, which due to fatty enlargement from orotic acid had more alpha-tocopherol. Hyperlipemic obese rats had plasma total lipids and alpha-tocopherol three times those of normal rats with the same intake of alpha-tocopherol. Tissue concentrations of the vitamin, however, were considerably lower in obese rats. Due to their large adipose mass, obese rats had considerably more total body alpha-tocopherol than normal rats. It was concluded that both plasma lipid levels and degree of adiposity are important factors in determining tissue deposition of alpha-tocopherol.
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PMID:Effect of plasma lipid levels and obesity on tissue stores of alpha-tocopherol. 115 26

1. Vitamin E content in the adipose tissue was examined in rats with and without vitamin E deficiency. With the progression of vitamin E depletion, the more rapid decrease in tocopherol concentration was observed in brown adipose tissue (BAT) than in white adipose tissue (WAT), and the rate of decrease of tocopherol was approximately three times faster in BAT than in WAT. After the intramuscular administration of 10 mg/kg of all-rac-tocopheryl acetate twice a week for two weeks to vitamin E-deficient rats, a similar pattern of increase was observed in the tocopherol concentrations of BAT and WAT, although the rate of increase was slower in WAT than in BAT. 2. Changes of tocopherol concentration in BAT and WAT were investigated in normo-nourished rats with hyperlipemia produced by the intramuscular injection of Triton WR-1339 for 7 days. A marked increase in tocopherol concentration was observed in both BAT and WAT in the late period of hyperlipemia, with the increase being greater in WAT. 3. The fatty acid composition of adipose tissue was compared between rats with and without vitamin E deficiency. No significant differences were observed in BAT and WAT between the two groups. 4. The glucose uptake of WAT was not altered in vitamin E-deficient rats when compared with control rats.
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PMID:Adipose tissues and vitamin E. 208 75

An increased lipid peroxides and a decreased production of prostacyclin have been shown in advanced atherosclerotic lesions and plasma. Our purpose was to determine whether the similar findings could be observed in cultured endothelial cells, and whether antioxidants could protect the cell against peroxide injury. In these experiments we have used bovine aortic endothelial cells in culture to address the issue of hyperlipidemia-induced arterial damage. Results of the present study showed that different concentration of hyperlipidemic sera from atherogenic rabbits induced a time- and dose-dependent alteration in the production of prostacyclin and levels of lipid peroxides in endothelial cells. Endothelial cells incubated with hyperlipidemic serum increased prostacyclin generation significantly during the initial stages and then continuously decreased. When endothelial cells were incubated for 36 h, TXA2 generation was also impaired and at the same time the cellular lipid peroxides content increased. There was a positive correlation between the concentration of hyperlipidemic serum and lipid peroxides and an inverse correlation with prostacyclin synthesis. The medium supplemented with antioxidant selenium or vitamin E showed a significant decrease in lipid peroxides and an increase in prostacyclin synthesis. These results suggest that both hyperlipidemic serum and lipid peroxides injury endothelial cells and inactivate prostacyclin synthetase, resulting in a decrease of prostacyclin production, while antioxidants have a protective effect. We conclude that the increase in lipid peroxides in association with hyperlipidemia results in alteration of prostacyclin synthesis that may play an important role in the pathogenesis of atherosclerosis.
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PMID:Effect of hyperlipidemic serum on lipid peroxidation, synthesis of prostacyclin and thromboxane by cultured endothelial cells: protective effect of antioxidants. 267 46

Restricted ovulator hens, which develop hyperlipidemia, were fed 1000 IU vitamin E per k of diet. These hens maintained their hyperlipidemia but plasma peroxide levels were reduced to those of laying hens. The intimal thickness of the aorta was measured by light microscopy. Hyperlipidemic hens which had high plasma peroxide levels had an increased intimal thickness as compared to laying hens. Hyperlipidemic hens which had their plasma peroxide levels reduced by dietary vitamin E had intimal thicknesses the same as laying hens. It is suggested that hyperlipidemia without lipid peroxidation either does not promote atherogenesis or does so at a reduced rate.
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PMID:Effect of dietary vitamin E on plasma lipids and atherogenesis in restricted ovulator chickens. 271 55

The effects of chronic ethanol feeding on hepatic lipid peroxidation, ascorbic acid, glutathione and vitamin E levels were investigated in rats fed low or adequate amounts of dietary vitamin E. Hepatic lipid peroxidation was significantly increased after chronic ethanol feeding in rats receiving a low-vitamin E diet, indicating that dietary vitamin E is an important determinant of hepatic lipid peroxidation induced by chronic ethanol feeding. No significant change was observed in hepatic non-heme iron content, but hepatic content of ascorbic acid and glutathione was increased by ethanol feeding. Both low dietary vitamin E and ethanol feeding significantly reduced hepatic alpha-tocopherol content, and the lowest hepatic alpha-tocopherol was found in rats receiving a combination of low vitamin E and ethanol. Plasma alpha-tocopherol was elevated after ethanol feeding, probably because of the associated hyperlipemia. Both the ratio of plasma alpha-tocopherol/plasma lipid and the red blood cell alpha-tocopherol were reduced by ethanol feeding. Furthermore, ethanol feeding caused a marked increase of hepatic alpha-tocopheryl quinone, a metabolite of alpha-tocopherol by free radical reactions. Ethanol feeding caused little changes of alpha-tocopherol and alpha-tocopheryl quinone content in mitochondria, whereas a striking increase in alpha-tocopheryl quinone was observed in microsomes. These data suggest that ethanol feeding causes a marked alteration of vitamin E metabolism in the liver and that the combination of ethanol with a low-vitamin E intake results in a decrease of hepatic alpha-tocopherol content which renders the liver more susceptible to free radical attack.
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PMID:Lipid peroxidation and antioxidant defense systems in rat liver after chronic ethanol feeding. 280 60

In contrast to deficiencies of vitamins A, D and K, little is known of the prevalence, clinical manifestations and mechanisms of vitamin E deficiency in adult patients with cholestasis. We measured serum vitamin E levels in 45 patients with primary biliary cirrhosis, 20 with primary sclerosing cholangitis, 9 with cryptogenic cirrhosis and 12 with alcoholic cirrhosis. To correct for the hyperlipidemia often found in patients with primary biliary cirrhosis and primary sclerosing cholangitis, total serum lipids were measured and vitamin E levels were expressed as the vitamin E/total serum lipid ratio. Serum vitamin A and D levels and prothrombin time were also determined. Six of 45 patients with primary biliary cirrhosis (13%) but none of the patients with sclerosing cholangitis, cryptogenic cirrhosis or alcoholic cirrhosis and subnormal vitamin E/total serum lipids ratios. Vitamin E deficiency was found in two of eight patients with asymptomatic primary biliary cirrhosis. There was no correlation between standard liver biochemical tests, fasting serum cholylglycine and vitamin E levels. Patients with primary biliary cirrhosis and primary sclerosing cholangitis had significantly lower vitamin E/total serum lipids ratios than patients with either cryptogenic or alcoholic cirrhosis. Twenty-three percent of patients with primary biliary cirrhosis were vitamin D deficient and 14% had low vitamin A levels. Two of the six patients with vitamin E deficiency were also deficient in vitamin D, only one was vitamin A deficient and none had prolonged prothrombin time. We also investigated the gastrointestinal absorption of vitamin E in nine patients with primary biliary cirrhosis and normal vitamin E levels as well as in six normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vitamin E deficiency in primary biliary cirrhosis: gastrointestinal malabsorption, frequency and relationship to other lipid-soluble vitamins. 292 55

Changes in RBC tocopherol level as an index for vitamin E status were studied in relation to plasma levels of tocopherol and lipids during pregnancy. Plasma tocopherol levels increased gradually and significantly during gestation. The changes depended on changes in total lipids in plasma, of which an increase in triglycerides was most predominant. A similar increase was shown in beta-lipoprotein levels, while HDL-cholesterol did not show any significant change. The ratio of plasma tocopherol to plasma total lipids, proposed as the best index for vitamin E status by Horwitt, remained unchanged during gestation, while RBC tocopherol levels somewhat decreased during the last trimester. The result indicates that tissue tocopherol available for biological function in the biomembrane may decrease due to hyperlipemia during gestation, as reflected in RBC tocopherol change.
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PMID:An evaluation of nutritional status of vitamin E in pregnant women with respect to red blood cell tocopherol level. 373 35

Vitamins are a group of organic compounds occurring naturally in food and are necessary for good health. Lack of a vitamin may lead to a specific deficiency syndrome, which may be primary (due to inadequate diet) or secondary (due to malabsorption or to increased metabolic need), and it is rational to use high-dose vitamin supplementation in situations where these clinical conditions exist. However, pharmacological doses of vitamins are claimed to be of value in a wide variety of conditions which have no, or only a superficial, resemblance to the classic vitamin deficiency syndromes. The enormous literature on which these claims are based consists mainly of uncontrolled clinical trials or anecdotal reports. Only a few studies have made use of the techniques of randomisation and double-blinding. Evidence from such studies reveals a beneficial therapeutic effect of vitamin E in intermittent claudication and fibrocystic breast disease and of vitamin C in pressure sores, but the use of vitamin A in acne vulgaris, vitamin E in angina pectoris, hyperlipidaemia and enhancement of athletic capacity, of vitamin C in advanced cancer, and niacin in schizophrenia has been rejected. Evidence is conflicting or inconclusive as to the use of vitamin C in the common cold, asthma and enhancement of athletic capacity, of pantothenic acid in osteoarthritis, and folic acid (folacin) in neural tube defects. Most of the vitamins have been reported to cause adverse effects when ingested in excessive doses. It is therefore worthwhile to consider the risk-benefit ratio before embarking upon the use of high-dose vitamin supplementation for disorders were proof of efficacy is lacking.
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PMID:Vitamin therapy in the absence of obvious deficiency. What is the evidence? 623 Feb 19


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