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

The behavior of native retinyl palmitate labeled intestinally derived lipoproteins and their remnants was studied in 8 NZW and 8 WHHL (5 homo- and 3 heterozygote) normal-fed rabbits and in 3 cholesterol-fed NZW, after 1 month of cholesterol feeding, and 3 and 5 months after resuming normal feeding. Palmitate labeled lipoproteins were produced by the intestine after administration of 50,000 IU of Vitamin A, together with olive oil via gastric intubation. Blood was drawn before and 3,6,9,12,24, and in some instances, 48 h later. Retinol (R) and retinyl palmitate (RP) were measured in whole serum and in the chylomicron, d less than 1006, d greater than 1006 less than 1019, d greater than 1019 less than 1063, d greater than 1063 less than 1210 g/ml lipoprotein fractions and in the infranatant. The R content of the serum was almost all concentrated in the infranatant, it did not change during the vitamin A test and was similar in WHHL, and normal- or cholesterol-fed NZW rabbits. In the normal-fed NZW the RP content of the serum increased within 6 h after giving the vitamin A fat meal (peak value less than 200 microgram/100 ml) and then decreased. In the WHHL homozygotes, the RP increased to a much greater degree (peak value 600-1820 micrograms) and for a much longer time, as it was still increased in the 5 cases studied after 24 h, and in 3 cases studied after 48 h. Similar RP curves were obtained in NZW rabbits, after 1 month of cholesterol feeding.(ABSTRACT TRUNCATED AT 250 WORDS)
Atherosclerosis 1990 Dec
PMID:Retinyl palmitate labeled intestinally derived lipoproteins accumulate in the circulation of WHHL rabbits. 210 74

A recent report based on data from the first National Health and Nutrition Examination Survey suggested that low intake of vitamin A may be associated with a greater risk of airway obstruction. We attempted to replicate these findings in a population-based sample of middle-aged adults (n = 15,743) who participated in the baseline examination of the Atherosclerosis Risk in Communities (ARIC) Study. Vitamin A intake was estimated from a 66-item food frequency questionnaire, and the presence of airway obstruction was determined by spirometry. Although airway obstruction was associated in ARIC with well-established risk factors such as age, sex, and smoking, there was little evidence for a role of vitamin A. With only one exception, vitamin A intake was unrelated to airway obstruction in all smoking categories using either categorical or continuous measures of lung function (FEV1, FVC, FEV1/FVC). Only among current smokers in the upper tertile of lifetime cigarette smoking (> 41 pack-years) was the odds ratio of having airway obstruction for the lowest quartile of vitamin A intake compared with the highest quartile elevated (1.7 [95% confidence interval 1.1 to 2.7]). Despite some biological plausibility that vitamin A intake may prevent obstructive lung disease, the inability to demonstrate association in a larger population study, with better estimation of usual dietary intake, casts doubt on the existence of causal relationship.
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PMID:Does dietary vitamin A protect against airway obstruction? The Atherosclerosis Risk in Communities (ARIC) Study Investigators. 792 73

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

We have shown earlier that sitostanol ester margarine lowers serum cholesterol by inhibiting cholesterol absorption so that, theoretically, there could be interference with the absorption of fat-soluble vitamins. Accordingly, we investigated whether sitostanol ester margarine affects the serum levels of vitamin D, retinol, alpha-tocopherol and alpha- and beta-carotenes during 1-year treatment in 102 subjects and 49 controls with moderate hypercholesterolemia. The vitamins were assayed at baseline on home diet, on margarine alone, after 1 year's consumption of sitostanol ester margarine and after an additional 2 months on home diet. In the sitostanol group, serum plant sterols, indicators of cholesterol absorption efficiency, were reduced up to -38% in relation to controls from home diet (P < 0.01) indicating that cholesterol absorption was markedly reduced. Vitamin D and retinol concentrations and the ratio of alpha-tocopherol to cholesterol were unchanged by sitostanol ester. Serum beta-carotenes and alpha-carotene concentration but not proportion were reduced in the sitostanol group from baseline and in relation to controls (P < 0.01). Retinol and vitamin D were unassociated with serum cholesterol, plant sterols or other vitamins, whereas alpha-tocopherol and carotenes were significantly associated with serum plant sterols suggesting that the higher cholesterol absorption efficiency, the higher the alpha-tocopherol and carotene levels in serum. We conclude that sitostanol ester did not affect vitamin D and retinol concentrations and alpha-tocopherol/cholesterol proportion, but reduced serum beta-carotene levels. Alpha-tocopherol and carotenes, but not vitamin D and retinol, were related to serum cholesterol and cholesterol absorption.
Atherosclerosis 1999 Aug
PMID:Retinol, vitamin D, carotenes and alpha-tocopherol in serum of a moderately hypercholesterolemic population consuming sitostanol ester margarine. 1048 54

In previous work we identified a transfer/diffusion process occurring in the postprandial state that more or less contributes to the accumulation of beta-VLDL in familial dysbetalipoproteinemia (FD). Here we present a new theoretical concept underlying chylomicron processing developed on the basis of extended quantitative analyses of fat loading experiments, with both vitamins A and E, performed in patients with familial combined hyperlipidemia (FCH) in comparison to patients with FD and control subjects. Recovery of triglycerides from the fat load in the plasma triglyceride pool was <4%, indicating a very effective lipolysis process with an active remnant generation. Vitamin A from the fat load was, over 48 h, quantitatively recovered in the plasma lipoprotein pool; vitamin E was recovered to 2241%. Nevertheless, transfer/diffusion of both vitamins showed similar patterns. At equilibrium, their contents correlated strongly with the lipoprotein concentrations, the slopes being similar for control subjects and both groups of patients. Only in those FD patients with the highest lipid values, did the vitamin A/lipoprotein mass ratio in the Sf>100 fraction deviate from the total group mean. In the Sf 15-100 fraction, most specific for 'remnants', vitamin A/cholesterol ratios for all subjects were uniform proving that beta-VLDL formation is a thermodynamic process regulated by concentration gradients and the lipophilicity of lipoprotein constituents, not a typical feature for patients with FD. In patients with FD, vitamin A in the plasma pool was recovered excessively (276%) in line with recognition in various pools as a result of the transfer/diffusion process in plasma.
Atherosclerosis 2000 Mar
PMID:Chylomicron processing in familial dysbetalipoproteinemia and familial combined hyperlipidemia studied with vitamin A and E as markers: a new physiological concept. 1070 29

Twenty eight men (age 34-77 years) who underwent an elective coronary angiography for coronary artery disease (CAD), were studied. They were divided into group A (luminal narrowing < 50%; n = 11) and group B (luminal narrowing > 50%; n = 17). Capillary gas chromatography was used for determination of fatty acids. Retinol and alpha-tocopherol were analyzed by reversed-phase high-performance liquid chromatography (HPLC), other parameters were determined spectrofluorometrically and spectrophotometrically. Severe coronary atherosclerosis in group B was associated with higher serum low density lipoprotein/high density lipoprotein (LDL/HDL) cholesterol ratio, triacylglycerols, and phospholipids (P < 0.05). Erythrocyte membrane fatty acids C14:0, C16:1 and C22:6n3 were significantly higher in group B (P < 0.05). We found significantly higher plasma polyunsaturated fatty acids (PUFA) C18:3n6 in group B, whereas plasma linoleic acid was not changed significantly. There was a significant increase of IDL-C18:0, LDL-C14:0 and HDL-C22:6n3 PUFA in group B. We conclude that disturbances in saturated fatty acids (SUFA) and PUFA metabolism are associated with coronary atherogenesis. Such abnormalities may include enhanced extrahepatic transport of C14:0 SUFA via LDL and its incorporation into cell membranes, and enhanced clearance of anti atherosclerotic C22:6n3 PUFA via serum HDL.
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PMID:Bioanalysis of PUFA metabolism and lipid peroxidation in coronary atherosclerosis. 1076 73

Oxidative stress is believed to be involved in the pathophysiology of a number of chronic diseases including atherosclerosis, diabetes, and cataracts and to accelerate the aging process. The aim of this study was to elucidate the role of various dietary fats in the in vivo modulation of CCl(4) induced oxidative stress using rat as a model. Rats were raised on diets enriched with saturated (Beef Tallow), n-9 (Sunola oil), n-6 (Safflower oil) or n-3 (Flaxseed oil) fatty acids and exposed to elevated oxidative stress by administration of CCl(4.) Plasma concentration of 8-iso-PGF(2alpha), antioxidant micronutrients and antioxidant enzymes were measured to examine changes to oxidative stress subsequent to the administration of CCl(4). The fatty acid profiles of plasma and RBC membranes reflected the fats fed in the different diets. CCl(4) administration had no significant effect on fatty acid composition of plasma or RBC lipids. Plasma 8-iso-PGF(2alpha) concentrations were elevated by CCl(4) administration regardless of the dietary fat fed. Within the induced oxidative groups the 8-iso-PGF(2alpha) concentrations were highest in Safflower oil followed by Sunola oil, Tallow and finally Flaxseed oil. Induction of oxidative stress by CCl(4) administration was associated with a significant reduction in Vitamin A content reaching a significantly lower concentration (P <0.05) in the Tallow and Flaxseed oil groups. Vitamin E concentrations were significantly lower (p = 0.01) in the Safflower oil and the Flaxseed oil than in the Tallow diet group following CCl(4) administration. Superoxide Dismutase (SOD) and Glutathione Peroxidase (GSHPx) activities were not affected by dietary fat manipulation. The results of this study indicate that dietary fat can modulate lipid peroxidation and antioxidant defenses when exposed to a pro-oxidant challenge.
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PMID:Modulation of carbon tetrachloride-induced oxidative stress by dietary fat in rats(open star). 1183 24

Oxidative stress is an important mechanism of cell death in Parkinson's disease (PD) and brain ischemia. Vitamins C, E and A are important antioxidants and deficiency of these agents has been implicated in the mechanisms of atherosclerosis. We measured the levels of the above antioxidant vitamins in 44 patients with PD, 12 patients with vascular parkinsonism (VP), 11 patients with other parkinsonism syndromes of various causes and 39 controls. Vitamin A levels did not differ between groups. Vitamins C and E were found decreased in VP, while they were normal in PD indicating low levels of antioxidant vitamins in VP and stressing the necessity of maintaining sufficient dietary intake of these agents in the elderly.
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PMID:Plasma levels of antioxidant vitamins C and E are decreased in vascular parkinsonism. 1554 5

We have investigated the effect of standard doses of two fibrates, gemfibrozil and fenofibrate, on fasting and postprandial remnant-like particles (RLP) in subjects with combined hyperlipidemia. Forty-eight subjects participated; of these, 14 underwent a Vitamin A-fat loading test before and after 6 months of treatment with gemfibrozil (n = 8) and fenofibrate (n = 6). Blood was drawn every 2h for 12h after the test meal. The postprandial response was calculated as the area under the curve (AUC). There was no difference in fasting levels and pre-treatment AUC for triglycerides (TG), RLP cholesterol (RLP-C), RLP triglycerides (RLP-TG) and retinyl palmitate (RetP) between the two treatment groups. There was also no difference in the treatment effect on all parameters between the two treatment groups. Combining the two treatment groups, treatment resulted in a significant reduction in fasting levels and AUC of all four parameters. Assigning the difference observed between pre-treatment AUC of the combined study group and AUC of a normolipidemic (NL) control group as 100%, fibrate treatment resulted in decreases in AUC for TG, RLP-C, RLP-TG and RetP of 68, 69, 69 and 94%, respectively. These results indicate that fibrates are effective agents in reducing the postprandial increase in remnant lipoprotein particles.
Atherosclerosis 2004 Feb
PMID:Effect of fibrates on postprandial remnant-like particles in patients with combined hyperlipidemia. 1501 49

The -514C/T polymorphism located in the promoter region of the hepatic lipase gene mediates changes in the plasma levels of the enzyme. The aim of this study was to determine whether the presence of this polymorphism modifies the postprandial clearance of lipoproteins of intestinal origin. 51 normolipemic volunteers, homozygotes for the allele E3 of the apo E were selected (26 homozygotes for the C allele and 25 carriers of the T allele in both homozygote and heterozygote form). The subjects underwent a Vitamin A fat-loading test. Blood was drawn every hour until the 6th hour and every 2 h and 30 min until the 11th hour to determine cholesterol and plasma triglycerides as well as cholesterol, triglycerides (TG) and retinyl palmitate in triacylglycerol-rich lipoproteins (chylomicrons and chylomicron remnants). Carriers of the T allele showed significantly lower postprandial levels of apolipoprotein B (P < 0.01), total TG in plasma (P < 0.05), small TRL-TG (P < 0.04), large TRL-TG (P < 0.04) and small TRL-cholesterol (P < 0.04) when compared to subjects homozygous for the C allele. Our data suggest that the T allele of the -514C/T polymorphism in the promoter region of the hepatic lipase gene is associated with a lower postprandial lipemic response.
Atherosclerosis 2004 May
PMID:Influence of the -514C/T polymorphism in the promoter of the hepatic lipase gene on postprandial lipoprotein metabolism. 1513 53


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