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

The antioxidant activities of 17-beta-estradiol (E2) and other steroid hormones were studied by determining their effect on copper-catalyzed (cell-free) and mononuclear cell-mediated oxidation of low-density lipoproteins (LDL), as measured by the production of thiobarbituric acid-reactive substances (TBARS). The oxidation of LDL increased linearly with copper concentrations ranging from 0 to 10 mumol/L. E2 at a concentration of 1 mumol/L inhibited LDL oxidation by 37% to 62% at the various concentrations of copper. In a time-course study, E2 at 1 mumol/L delayed the onset of LDL oxidation in the presence of 5 mumol/L copper. E2 (1 mumol/L) inhibited TBARS production catalyzed by 5 mumol/L copper by 54%, compared with 60% inhibition by 1 mumol/L butylated hydroxytoluene (BHT), a known inhibitor of lipid peroxidation. Estriol at 5 mumol/L decreased LDL oxidation by 49%. Dehydroepiandrosterone (DHEA), testosterone, and estrone had no significant effects. E2 was also an effective inhibitor of mononuclear cell (MNC)-mediated oxidation of LDL, but had no effect on superoxide production by these cells. The onset of TBARS formation from cell-mediated LDL oxidation was also delayed by incubation with 1 mumol/L E2. The results indicate that estrogen may protect against atherosclerosis by inhibiting lipoprotein oxidation.
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PMID:The inhibition of low-density lipoprotein oxidation by 17-beta estradiol. 132 22

The purpose of this study was to compare the relative effect of n-3 fatty acids on plasma lipids and platelet function in normolipemic subjects (n = 8) with plasma Lp(a) levels greater than 30 mg/dl and normolipemic subjects (n = 7) without detectable plasma Lp(a) concentrations. Six weeks of dietary supplementation (3.8 g EPA and 2.9 g DHA/d) significantly reduced (P less than 0.005) plasma TGs in both groups whereas no changes of plasma TC, LDL-C, HDL-C, and Lp(a), respectively, were found. Collagen- or thrombin-stimulated platelet aggregation and collagen- or thrombin-induced TXB2 generation from platelets decreased by approx. 45% in Lp(a)-negative and Lp(a)-positive platelet donors after a 6 week dietary intake. Four more weeks without n-3 supplementation restored the pretreatment values of TGs, platelet aggregability and TXB2 release. The biophysical properties of platelets from normolipemics with and without high plasma Lp(a) concentrations revealed a similar structural order of platelets at 37 degrees C using DPH, TMA-DPH, or 6-AS as fluorescent probes. Also similar temperature-dependent changes in platelet fluidity from 37 degrees C to 17 degrees C were observed in platelet preparations from Lp(a)-positive and Lp(a)-negative subjects. However, no subtle changes in the structural order of platelets due to nutrient intakes were found in all subjects (n = 15, 19-28 yrs) using fluorescence polarization technique. The present data suggest a similar in vitro platelet behaviour from normolipemic subjects with and without high plasma levels of Lp(a) (which is considered a risk for premature atherosclerosis) in contrast to platelet aggregability and platelet fluidity in certain hyperlipidemic stages.
Atherosclerosis 1991 Jun
PMID:Effects of dietary fish oil supplementation on platelet aggregability and platelet membrane fluidity in normolipemic subjects with and without high plasma Lp(a) concentrations. 183 37

There is clinical and epidemiologic evidence that long chain polyunsaturated fatty acids of the n-3 series, (AGPI n-3): eicosapentaenoic acid (EPA 20:5 n-3) and docosahexaenoic acid (22:6 n-3) decrease the incidence of heart attack, coronary restenosis and also platelet aggregation, leukotriene synthesis and arterial pressure. They also decrease significantly the severity of atherosclerosis in hyperlipidemic models. Some of these results are obtained after daily intake of 3g or more of AGPI n-3. Marine oils are very rich in AGPI n-3 but rarely the amount is larger than 20%. Due to this fact there is great interest in the possibility of obtaining concentrates of AGPI n-3 with a high coefficient of intestinal absorption. EPA and DHA ethyl esters are able to be concentrated over 90% but their absorption is incomplete. For the moment AGPI n-3 can be concentrated as free fatty acids (AGL). Squid oil (Illex argentinus) is one of the natural oils with the highest concentration of AGPI n-3 (31 to 34%). In this paper, we have studied the incorporation of AGPI n-3 to plasmatic lipoproteins of rats fed during 28 days with diets supplemented with squid oil (Ac) or AGL obtained from the same oil. Both groups were compared with a control group (C, n = 5) fed on a standard diet. The composition of oil fatty acids and of AGL is almost identical: EPA 13.6% and DHA 17.7% (Table 1). Daily intake of AGPI n-3 was very similar: in the Ac group (n = 7) 80 mg/day and in the AGL group (n = 7) 90 mg/day.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Incorporation of squid oil fatty acids to plasma lipoproteins in rats]. 184 Mar 6

Intraindividual comparisons of diets supplemented with sunflowerseed oil (rich in linoleic acid, LA, C18:2n-6), linseed oil (enriched with alpha-linolenic acid, LNA, C18:3n-3) and canned mackerel (rich in eicosapentaenoic acid, EPA, C20:5n-3 and docosahexaenoic acid, DHA, C22:6n-3) were made in 30 patients with primary hyperlipoproteinemia (HLP) of phenotypes IIa (n = 9), IIb (n = 7), IV (n = 7) and V (n = 7). The lipid- and blood pressure-lowering effects of polyunsaturated fatty acids (PUFA), particularly those of the EPA- and DHA-rich diet, were confirmed irrespective of the type of HLP. Apolipoproteins A-I and B remained unchanged. The most remarkable finding was a substantial depression of free fatty acids (FFA) within a standardized glucose tolerance test (GTT) associated with the fall of serum triglycerides after diets enriched with n-6 and especially after those supplemented with n-3 PUFA. It was suggested that the decrease of FFA indicates reduced peripheral lipolysis, which might be a hitherto ignored factor involved in the triglyceride-lowering action of n-6 and, more pronounced, of n-3 PUFA.
Atherosclerosis 1990 Aug
PMID:A possible contribution of decrease in free fatty acids to low serum triglyceride levels after diets supplemented with n-6 and n-3 polyunsaturated fatty acids. 214 66

The concentration of dehydroepiandrosterone sulfate (DHEA-S) in human plasma is higher than any other steroid. Recent evidence has suggested an inverse relationship between plasma DHEA levels and the development of coronary atherosclerosis in humans. We used the cholesterol-fed rabbit model to investigate whether DHEA feeding would diminish aortic fatty streak formation in this model. Fifteen New Zealand White rabbits were fed rabbit chow supplemented with 0.5% cholesterol (wt/wt). Seven animals were, in addition, fed DHEA, 0.5% of diet (wt/wt). Animals were sacrificed after 2 months, and the aortic involvement with fatty streaks was evaluated by computerized planimetry of Sudan IV-stained aortas and by chemical analysis of aortic wall lipids. Compared to controls, DHEA-fed animals had similar plasma levels of total, very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol, corticoids, and estrogens. DHEA-fed animals had higher plasma levels of total, VLDL, and LDL triglycerides and lower HDL triglycerides than did controls. DHEA feeding resulted in 30% and 40%, respectively, inhibition of fatty streak formation by chemical analysis and planimetry. We conclude that DHEA feeding inhibits the development of aortic fatty streaks in cholesterol-fed rabbits, independent of changes in plasma total and LDL cholesterol levels of DHEA conversion to estrogens or corticoids.
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PMID:Dehydroepiandrosterone feeding prevents aortic fatty streak formation and cholesterol accumulation in cholesterol-fed rabbit. 252 96

Plasma levels of dehydroepiandrosterone sulfate (DHEA-S), testosterone, dihydrotestosterone (DHT) androstenedione, sex hormone-binding globulin (SHBG), lipoproteins, apolipoproteins and high density lipoprotein (HDL) subfraction were measured in 32 men aged 26-40 years after myocardial infarction (MI) suffered at least 3-4 months prior to the study, who were normocholesterolemic and had angiographically demonstrated coronary occlusion. The control group consisted of 76 healthy men aged 25-40 years. Blood samples were obtained in the morning from fasting subjects. A significant decrease in plasma DHEA-S and DHT levels were found in MI patients. Also, a significant decrease in HDL-cholesterol, HDL2-cholesterol (HDL2-C) and apolipoprotein A-I, an increase in apolipoprotein B and LDL-cholesterol (LDL-C) levels were observed in those patients as compared with healthy men. However, there were no differences in testosterone, androstenedione and SHBG concentrations between the groups. Significant correlations between testosterone and HDL2-C (r = 0.46, P less than 0.01), as well as between DHEA-S and HDL3-C (r = 0.39, P less than 0.05) levels in MI patients were observed. These results suggest that decreased levels of plasma DHEA-S and DHT may promote the development of coronary atherosclerosis in men.
Atherosclerosis 1989 Oct
PMID:Decreased plasma dehydroepiandrosterone sulfate and dihydrotestosterone concentrations in young men after myocardial infarction. 253 16

The effect of long-term manipulation of dietary lipid intake on platelet and vessel wall lipid composition and eicosanoid synthesis was investigated. Rats were fed a standard diet (REF diet) supplemented (12% w/w) with either sheep fat (SF), sunflower seed oil (SSO) or tuna fish oil (TFO) for a period of 15 months. Significant compositional changes both in the aorta and platelets were observed following dietary lipid treatment and differences between these tissues were particularly apparent with regard to the incorporation and conversion of n-3 fatty acids. For example, platelets displayed a selective accumulation of eicosapentaenoic acid (EPA, 20:5 n-3) over docosahexaenoic acid (DHA, 22:6, n-3), but in the aorta the proportion of DHA was considerably higher than that of EPA. In both tissues, compared to REF diet, n-3 dietary fatty acids replaced the n-6 unsaturates 20:4 and 22:4, but did not affect the proportion of linoleic acid. In contrast to aorta, the unsaturation index for platelet membrane varied significantly between dietary groups. The capacity of aorta and platelets to generate PGI2-like activity and thromboxane was unaltered by the SSO diet. However, changes were seen following SF and TFO supplementation. Rats fed the SF diet displayed a greater synthetic capacity whilst in animals maintained on TFO diet the synthesis of these two eicosanoids was considerably suppressed. The SF group displayed the highest value for PGI2/TXB2 ratio whereas TFO diet fed rats showed the lowest which may partly be due to synthesis of TXA3. The reduction in eicosanoids following the tuna fish oil supplementation can be explained on the basis of concurrent compositional changes.(ABSTRACT TRUNCATED AT 250 WORDS)
Atherosclerosis 1987 Aug
PMID:Long-term saturated fat supplementation in the rat causes an increase in PGI2/TXB2 ratio of platelet and vessel wall compared to n-3 and n-6 dietary fatty acids. 282 Apr 32

In this study we investigated the effects of a daily supplementation of 6 g Super-EPA containing 3 g of the marine fatty acids eicosapentaenoic acid (EPA, C 20:5 omega-3) and docosahexaenoic acid (DHA, C 22:6 omega-3) for a period of 8 weeks in nine patients on continuous ambulatory peritoneal dialysis. The concentrations of both HDL2 cholesterol and total HDL cholesterol increased (P less than 0.05) and there was a marked reduction in triglycerides (P less than 0.05). The viscosity of erythrocyte suspensions at a haematocrit of 0.80 decreased at most shear rates, suggesting an increased erythrocyte deformability. Mean corpuscular volume decreased (P less than 0.05) and total cholesterol and phospholipids in the erythrocyte membrane increased. We conclude that the daily use of 3 g of omega-3 polyunsaturated fatty acids by CAPD patients produces favourable effects on lipid profile and viscosity of erythrocyte suspensions, which may be of importance in protecting these patients against a further progression of atherosclerosis.
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PMID:The effect of fish oil on lipid profile and viscosity of erythrocyte suspensions in CAPD patients. 283 74

Dehydroepiandrosterone (DHEA) is an endogenous steroid that blocks carcinogenesis, retards aging, and exerts antiproliferative properties. In vitro, it is a potent inhibitor of glucose-6-phosphate dehydrogenase, the first committed step of the pentose phosphate pathway. In man, serum levels of DHEA and its sulfate peak in early adulthood and drop markedly with age. Epidemiologic evidence indicates that low levels of DHEA or its sulfate conjugate are linked to an increased risk of developing cancer or of death from cardiovascular disease. Like cancer, atherosclerosis is a proliferative process characterized by both initiation and promotion phases. This similarity provided a framework in which to study the antiatherogenic effects of DHEA. Rabbits were randomly assigned to four groups. Two groups of rabbits received aortic endothelial injury by balloon catheter and were fed a 2% cholesterol diet for 12 wk. DHEA, 0.5%, was incorporated into the diet of one group receiving the 2% cholesterol diet and endothelial injury and also into the diet of one of the control groups. Animals were killed after 12 wk and aortas, hearts, and livers were studied. Plasma samples were analyzed for total cholesterol, VLDL, LDL, HDL, triglycerides, DHEA, and DHEA-sulfate levels. The atherogenic insult resulted in severe atherosclerosis in animals not treated with DHEA. In those receiving DHEA there was an almost 50% reduction in plaque size (P = 0.006), inversely related to the serum level of DHEA attained. Fatty infiltration of the heart and liver were also markedly reduced. These beneficial actions were not attributable to differences in body weight gain, food intake, total plasma cholesterol or distribution of cholesterol among the VLDL, LDL, or HDL fractions. The results show that high levels of plasma DHEA inhibit the development of atherosclerosis and they provide an important experimental link to the epidemiologic studies correlating low DHEA-sulfate plasma levels with an enhanced risk of cardiovascular mortality.
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PMID:Reduction of atherosclerosis by administration of dehydroepiandrosterone. A study in the hypercholesterolemic New Zealand white rabbit with aortic intimal injury. 296 22

Eight patients with type IV and V hyperlipoproteinemia were put on a mackerel and herring diet of an isocaloric regimen for 2 weeks, in a cross-over design. At the end of the dietary periods a predominant increase of eicosapentaenoic acid (EPA - C20:5, n-3) in cholesterol esters and of docosahexaenoic acid (DHA - C22:6, n-3) in serum triglycerides, being more pronounced after mackerel as compared to herring diet, could be confirmed. After mackerel diet serum triglycerides and total cholesterol were significantly lower, returning to basal levels 3 months later. High density lipoprotein (HDL) cholesterol appeared slightly increased after mackerel diet and decreased to initial values thereafter. After herring diet, which contained half as much EPA as compared to mackerel diet, the differences were minor. The decline of free fatty acids (FFA) and insulin at the end of the mackerel period reached the level of significance 60 min and 120 min, respectively, after glucose load. A significantly lower systolic blood pressure in recumbent and upright position after the mackerel period could be found, whereas diastolic pressure and blood pressure after herring diet remained unchanged.
Atherosclerosis 1985 Jul
PMID:Influence on serum lipids, lipoproteins and blood pressure of mackerel and herring diet in patients with type IV and V hyperlipoproteinemia. 299 34


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