Omega-3 fatty acids do not improve endothelial function in virologically suppressed HIV-infected men: a randomized placebo-controlled trial.

Omega-3 fatty acids decrease cardiovascular disease (CVD) mortality possibly due to antiinflammatory effect. Inflammation and endothelial dysfunction likely play a role in the heightened CVD risk in HIV. Our goal was to evaluate the effect of omega-3 fatty acids primarily on endothelial function and inflammation in HIV-infected adults with moderate CVD risk on stable antiretroviral therapy. We conducted a 24-week, randomized, double-blind, placebo-controlled study to evaluate the effect of omega-3-acid ethyl esters 1 g twice a day. Flow-mediated dilation (FMD) of the brachial artery, lipoproteins and markers of inflammation, endothelial activation, coagulation, and insulin resistance were measured at entry and week 24. There were no within- or between-group differences in change in FMD over 24 weeks (mean change in FMD -0.13% vs. 1.5% for treatment vs. placebo; p=0.21). There were no between-group differences in changes in lipoprotein levels or biomarkers tested, except soluble tumor necrosis factor receptor-I, which favored omega-3-acid ethyl esters. Omega-3 fatty acids did not improve endothelial function or activation, coagulation, or insulin resistance in virologically suppressed, HIV-infected men with moderate CVD risk; however, inflammation tended to improve. This suggests that omega-3 fatty acids may not be potent enough to counteract the enhanced inflammation and endothelial dysfunction due to HIV and antiretrovirals.

Plasma fibrinogen concentration in pediatric patients treated with an elimination diet based on soy proteins and casein hydrolyzate.

PURPOSE: Fibrinogen is one of the most discussed new risk factors of atherosclerosis. The aim of the study was to assess the relationship between fibrinogen concentration and classic risk markers of atherosclerosis in a group of children aged from 2 to 6 with or without a family history of circulatory system diseases (FHCAD) (American Academy of Pediatrics--AAP criteria). The study also considered the impact of allergies/food intolerance treatment with elimination diets on the concentration of atherosclerosis markers specially fibrinogen. INCLUSION CRITERIA: a) family history of early occurrence of circulatory system diseases (FHCAD+) according to AAP standards; b) the type and duration of elimination diet continued in infancy and early childhood. 134 of 388 children were included in the investigation. RESULTS: The analysis of data relating to the so-called classic biochemical risk factors of atherosclerosis (total cholesterol--TC, HDL, LDL, triglycerides, glucose) did not reveal any differences between the tested groups. It was found that in the FHCAD+ group the concentration of fibrinogen was statistically higher than in the group with a negative family history. It was discovered that the type of elimination diet had no effect on fibrinogen level in the FHCAD+ group. In the group of children with negative family history the concentration of fibrinogen was statistically lower in the group on casein hydrolysate than in children treated with soy formula. CONCLUSIONS: The initial interview in pediatrics should include information on the patient's family history of atherosclerosis. In case of a positive family history, fibrinogen, as one of atherosclerosis risk factors, should be monitored.

Weight loss associated with reduced intake of carbohydrate reduces the atherogenicity of LDL in premenopausal women.

The effect of a 3-tier intervention including dietary modifications (ie, moderate energy restriction, decreased carbohydrate, increased protein), increased physical activity, and the use of carnitine as a dietary supplement was evaluated on plasma lipids and the atherogenicity of low-density lipoprotein (LDL) particles in a population of overweight and obese premenopausal (aged 20-45 years) women. Carnitine or a placebo (cellulose) was randomly assigned to the participants using a double-blind design. Carnitine supplementation was postulated to enhance fat oxidation resulting in lower concentrations of plasma triglycerides. Seventy women completed the 10-week protocol, which followed a reduction in their energy intake by 15% and a macronutrient energy distribution of 30% protein, 30% fat, and 40% carbohydrate. In addition, subjects increased the number of steps taken per day by 4500. As no differences were observed between the carnitine and placebo groups in all the measured parameters, all subjects were pooled together for statistical analysis. Participants decreased (P<.01) their caloric intake (between 4132.8 and 7770 kJ) and followed prescribed dietary modifications as assessed by dietary records. The average number of steps increased from 8950+/-3432 to 12764+/-4642 (P<.001). Body weight, plasma total cholesterol, LDL cholesterol, and triglyceride were decreased by 4.5%, 8.0%, 12.3%, and 19.2% (P<.0001), respectively, after the intervention. Likewise, apolipoproteins B and E decreased by 4.5% and 15% (P<.05) after 10 weeks. The LDL mean particle size was increased from 26.74 to 26.86 nm (P<.01), and the percent of the smaller LDL subfraction (P<.05) was decreased by 26.5% (P<.05) after 10 weeks. In addition, LDL lag time increased by 9.3% (P<.01), and LDL conjugated diene formation decreased by 23% (P<.01), indicating that the susceptibility of LDL to oxidation was decreased after the intervention. This study suggests that moderate weight loss (<5% of body weight) associated with reduced caloric intake, lower dietary carbohydrate, and increased physical activity impacts the atherogenicity of LDL.

Dietary copper supplements modulate aortic superoxide dismutase, nitric oxide and atherosclerosis.

The objective was to test the hypothesis that dietary copper inhibits atherosclerosis by inducing superoxide dismutase (SOD) and potentiating nitric oxide (NO). New Zealand White rabbits were fed either a cholesterol diet (n = 8) or a cholesterol diet containing 0.02% copper acetate (n = 8) for 13 weeks. We found that the intimal area was significantly smaller in the animals supplemented with copper (P < 0.005), although integrated plasma cholesterol levels were not significantly different. This was associated with a significant increase in aortic copper content (P < 0.05), SOD activity (P < 0.05) and Cu/Zn SOD mRNA (P < 0.05) and a significant decrease in nitrotyrosine content (P < 0.05). Furthermore, there was a positive correlation between aortic copper content and SOD activity (P < 0.005, R(2) = 0.83) and a negative correlation between aortic superoxide dimutase activity and nitrotyrosine content (P < 0.005, R(2) = 0.93). In organ bath experiments, the relaxation of precontracted carotid artery rings to calcium ionophore was greater in animals supplemented with copper. No difference in response to sodium nitroprusside was observed. These data suggest that in the cholesterol-fed rabbit, copper supplements inhibit the progression of atherosclerosis by increasing SOD expression, thereby reducing the interaction of NO with superoxide, and hence potentiating NO-mediated pathways that may protect against atherosclerosis.

The case for dietary calcium restriction in patients with atherosclerosis.

An increasingly vast set of data is linking the process of vascular calcification to the metabolism of calcium and phosphorus. This phenomenon is already relatively well understood in renal failure patients. A similar phenomenon, however, could be taking place in the general population. This may indicate a need for a reassessment of calcium supplementation, including the ingestion of milk, not only in dialysis patients, but also in patients with preserved renal function. Given the fact that no clear prospective randomized evidence exists to show what may be the impact on prognosis of patients with atherosclerosis, caused by the ingestion of milk and milk derivatives, containing calcium and lactose, as is currently recommended to prevent bone disease in the general population, a case could be made to recommend restriction of such dietary products in atherosclerosis patients, until precise data have been obtained, in controlled, prospective studies, and especially so in patients with no evidence of osteoporosis. Such a case would not be a strong one at the present stage, but neither would be the opposite view. The recommendation that could be made at this stage would be that patients with significant atherosclerotic disease should be informed that the ingestion of milk, and calcium supplementation in general, has neither been conclusively proven to be safe, nor the opposite.

Effect of low dose atorvastatin versus diet-induced cholesterol lowering on atherosclerotic lesion progression and inflammation in apolipoprotein E*3-Leiden transgenic mice.

OBJECTIVE: To evaluate whether low-dose atorvastatin suppresses atherosclerotic lesion progression and inflammation in apolipoprotein E*3 (apoE*3)-Leiden mice beyond its cholesterol-lowering effect. METHODS AND RESULTS: ApoE*3-Leiden mice were fed a high-cholesterol (HC) diet until mild atherosclerotic lesions had formed. Subsequently, HC diet feeding was continued or mice received HC supplemented with 0.002% (w/w) atorvastatin (HC+A), resulting in 19% plasma cholesterol lowering, or mice received a low-cholesterol (LC) diet to establish a plasma cholesterol level similar to that achieved in the HC+A group. HC+A and LC diet reduced, significantly and to the same extent, lesion progression and complication in the aortic root, as assessed by measuring total atherosclerotic lesion area, lesion severity, and macrophage and smooth muscle cell area. In the aortic arch, HC+A but not LC blocked lesion progression. HC+A and LC reduced vascular inflammation (ie, expression of macrophage migration inhibitory factor , plasminogen activator inhibitor- 1, matrix metalloproteinase-9), but HC+A additionally suppressed vascular cell adhesion molecule-1 expression and, in parallel, monocyte adhesion. In contrast, low-dose atorvastatin showed no antiinflammatory action toward hepatic inflammation markers (serum amyloid A, C-reactive protein [CRP]) in apoE*3-Leiden mice and human CRP transgenic mice. CONCLUSIONS: Low-dose atorvastatin cholesterol-dependently reduces lesion progression in the aortic root but shows antiinflammatory vascular activity and tends to retard atherogenesis in the aortic arch beyond its cholesterol-lowering effect.

Vitamins in human arteriosclerosis with emphasis on vitamin C and vitamin E.

INTRODUCTION: This review focuses on the process of arteriosclerosis arising from oxidative stress on lipoproteins and the general failure of randomized human trials using vitamins to retard this process. REVIEW: As well as clinical trials, the paper reviews the mechanisms by which a variety of oxidants act. Antioxidants are discussed, emphasizing interactions of vitamins C and E with transition metals that can lead to prooxidation. There is a focus on interactions between supplemental or co-antioxidants that counterbalance prooxidant effects of one another. CONCLUSIONS: It is concluded that normal cellular supplementation mechanisms are poorly accessible in the arteriosclerotic plaque leading to a prooxidant environment in which the haphazard introduction of vitamins could potentially be hazardous. Continued investigations into basic and clinical redox interactions of the kind discussed in this review using new measuring techniques may lead to approaches whereby antioxidants can be introduced into tissue in controlled ways for reducing arteriosclerosis.

Soy protein with isoflavones, but not an isoflavone-rich supplement, improves arterial low-density lipoprotein metabolism and atherogenesis.

OBJECTIVE: We sought to determine if arterial LDL metabolism contributes to the decreased atherosclerosis seen with soy and if isolated isoflavones would have similar effects. METHODS AND RESULTS: Ovariectomized monkeys were fed an atherogenic diet for 20 weeks with a protein source of (1) casein/lactalbumin (CAS, n=20), (2) soy protein isolate (SOY, n=20), or (3) casein/lactalbumin with isolated soy isoflavones (ISO, n=17). Plasma lipoprotein concentrations were improved with SOY but not ISO. Arterial LDL metabolism was characterized with one subset (n=12/group) injected with dual-labeled tyramine-cellobiose (TC)-LDL (125I-TC-131I-LDL) 24 hours before necropsy to determine LDL degradation and accumulation, while another subset (n=8/group) was injected with 125I-TC-LDL 1 hour before necropsy to determine LDL permeability and delivery. CONCLUSIONS: Coronary artery LDL degradation was reduced by 50% (P=0.02) with SOY but not with ISO compared with CAS. Neither treatment altered arterial permeability. Reduced LDL degradation with SOY was due to decreased arterial LDL delivery (P=0.02). Carotid artery cholesterol ester was also decreased with SOY, but not with ISO. Plasma isoprostanes or plasma markers of inflammation did not differ among treatment groups. Thus, the decreased arterial LDL delivery and subsequent LDL degradation may explain, in part, the atheroprotective effects of soy.

Alpha-tocopherol protects against diet induced atherosclerosis in New Zealand white rabbits.

In this study, we asked the question "does alpha-tocopherol supplementation prevent an increase in total plasma cholesterol (TPC) concentration and reduce the deposition of cholesterol in arterial plaques of rabbits fed atherogenic diets?" Isocaloric diets containing 0.1% cholesterol to induce atherosclerosis were enriched in one of three fats: saturated fats (SAT), monounsaturated fats (MONO), or n-6 polyunsaturated fats (POLY). Half of each of the three diets were supplemented with 2,500 IU alpha-tocopherol/kg-diet. Unsupplemented diets contained 25 IU alpha-tocopherol/kg-diet. Rabbits supplemented with alpha-tocopherol had plasma alpha-tocopherol concentrations 10-fold higher and an average TPC concentration 31% lower, P = 0.017, than rabbits fed unsupplemented diets. Among the three fat-fed groups, the difference was greatest for the POLY fat fed group (54%, P = 0.041). POLY fat-fed rabbits without alpha-tocopherol supplementation had plasma HDL cholesterol concentrations that were less than half that of rabbits fed other fats, P < or = 0.0001. In general, differences in mean esterified artery cholesterol concentrations among the three fat-fed groups, with and without alpha-tocopherol supplementation, paralleled differences in TPC concentration among the groups. This study suggests that for rabbits fed high pharmacological doses of alpha-tocopherol, atherosclerosis can be diminished in situations where the plasma cholesterol concentrations are also significantly lower.

Oral L-arginine does not improve endothelial dysfunction in children with chronic renal failure.

BACKGROUND: Cardiovascular disease is a major cause of mortality amongst patients with chronic renal failure (CRF). L-arginine has been used to improve endothelial function by increasing nitric oxide (NO) bioavailability and in animal models this in turn has attenuated the progression of atherosclerosis. We examined whether dietary L-arginine supplementation improved endothelial function in children with CRF. METHODS: A randomized, double-blind, placebo-controlled, crossover trial of L-arginine was conducted in 21 normotensive children aged 11.5 +/- 3 (7 to 17) years with CRF (GFR 27.4 +/- 13.2 mL/min/1.73 m(2)) in whom endothelial dysfunction had previously been demonstrated. We examined the effect of L-arginineon the endothelial response to shear stress (NO-dependent) using a non-invasive technique of high-resolution ultrasound. Each subject was studied before and after 4 weeks of L-arginine (2.5 g/m(2) or 5 g/m(2) x 3/day) or placebo, separated by a rest period of 4 weeks. Brachial artery diameter was measured at rest, during increased flow (endothelial-dependent dilation) and after 25 microg of glyceryl trinitrate (endothelial-independent dilation) at each visit. RESULTS: After oral L-arginine, plasma L-arginine levels rose from 82 +/- 20 to 179 +/- 110 micromol/L (P < 0.001). No significant change in endothelial-dependent dilation during L-arginine (7.96 +/- 2.35 to 7.71 +/- 3.22%; P> 0.05) or placebo (8.2 +/- 2.89 to 8.3 +/- 3.14%; P> 0.05) was noted. There was no change in endothelial-independent dilation. CONCLUSION: Endothelial function was not improved with L-arginine, suggesting that dietary supplementation is not a useful clinical approach in children with CRF.

Antioxidative and hypolipidemic effects of barley leaf essence in a rabbit model of atherosclerosis.

The antioxidative and hypolipidemic effects of barley leaf essence (BL) were investigated in a rabbit model of atherosclerosis. Twenty-four New Zealand White male rabbits were assigned randomly into four dietary groups. The normal group was fed regular rabbit chow and the control group was fed a chow containing 0.5% cholesterol and 10% corn oil. The BL group and the probucol group were fed the same diet as the control group plus 1% (w/w) BL or 1% (w/w) probucol, respectively. The plasma levels of total cholesterol, triacylglycerol, lucigenin-chemiluminescence (CL) and luminol-CL were increased in the control group compared to the normal group; and they were decreased in the BL group and the probucol group compared to the control group. The value of T50 of red blood cell hemolysis and the lag phase of low-density lipoprotein oxidation increased in the BL group and in the probucol group compared to the controls. Ninety percent of the intimal surface of the thoracic aorta was covered with atherosclerotic lesions in the control group, but only 60% of the surface was covered in the BL group. This 30% inhibition of hyperlipidemic atherosclerosis by BL was associated with a decrease in plasma lipids and an increase in antioxidative abilities (as measured by T50, lag phase and CL). These results suggest that the antioxidant and hypolipidemic effects of BL could be useful in the prevention of cardiovascular disease in which atherosclerosis is important.

Supplementation of plant sterols and minerals benefits obese Zucker rats fed an atherogenic diet.

In most hypertensive rat models, serum total cholesterol is typically low and the cholesterol is primarily in the HDL rather than the LDL fraction. This difference from humans usually makes these animals unsuitable for experimental atherosclerosis studies. In the present study, we induced severe hypercholesterolemia including a 10-fold increase in serum LDL cholesterol, endothelial dysfunction and hypertension as well as vascular and renal damage in obese Zucker rats by feeding a human-type high fat, high cholesterol and high salt diet (butter 18, cholesterol 1 and NaCl 6 g/100 g dry weight). Supplementation of this atherogenic diet with plant sterols (1 g/100 g) and replacing the NaCl partially by calcium, magnesium and potassium effectively prevented the diet-induced increases in total and LDL cholesterols and 24-h systolic and mean blood pressures, and markedly improved endothelial function. Plant sterols and the minerals also protected against vascular and renal damage and extended the life span of the obese Zucker rats by 60% compared with the rats fed the atherogenic diet. Our findings suggest that human-type cardiovascular disorders can be induced in obese Zucker rats by feeding a human-type atherogenic diet. This seems to be a suitable animal model for experimental studies on atherosclerosis and hypertension as well as for evaluating new dietary approaches to reducing cardiovascular risk.

Dietary cosupplementation with vitamin E and coenzyme Q(10) inhibits atherosclerosis in apolipoprotein E gene knockout mice.

Intimal oxidation of LDL is considered an important early event in atherogenesis, and certain antioxidants are antiatherogenic. Dietary coenrichment with vitamin E (VitE) plus ubiquinone-10 (CoQ(10), which is reduced during intestinal uptake to the antioxidant ubiquinol-10, CoQ(10)H(2)) protects, whereas enrichment with VitE alone can increase oxidizability of LDL lipid against ex vivo oxidation. In the present study, we tested whether VitE plus CoQ(10) cosupplementation is more antiatherogenic than either antioxidant alone, by use of apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet without (control) or with 0.2% (wt/wt) VitE, 0.5% CoQ(10), or 0.2% VitE plus 0.5% CoQ(10) (VitE+CoQ(10)) for 24 weeks. None of the supplements affected plasma cholesterol concentrations, whereas in the VitE and CoQ(10) groups, plasma level of the respective supplement increased. Compared with control, plasma from CoQ(10) or VitE+CoQ(10) but not VitE-supplemented animals was more resistant to ex vivo lipid peroxidation induced by peroxyl radicals. VitE supplementation increased VitE levels in aorta, heart, brain, and skeletal muscle, whereas CoQ(10) supplementation increased CoQ(10) only in plasma and aorta and lowered tissue VITE: All treatments significantly lowered aortic cholesterol compared with control, but only VitE+CoQ(10) supplementation significantly decreased tissue lipid hydroperoxides when expressed per parent lipid. In contrast, none of the treatments affected aortic ratios of 7-ketocholesterol to cholesterol. Compared with controls, VitE+CoQ(10) supplementation decreased atherosclerosis at the aortic root and arch and descending thoracic aorta to an extent that increased with increasing distance from the aortic root. CoQ(10) significantly inhibited atherosclerosis at aortic root and arch, whereas VitE decreased disease at aortic root only. Thus, in apoE-/- mice, VitE+CoQ(10) supplements are more antiatherogenic than CoQ(10) or VitE supplements alone and disease inhibition is associated with a decrease in aortic lipid hydroperoxides but not 7-ketocholesterol.

Antithrombotic potential of olive oil administration in rabbits with elevated cholesterol.

Olive oil is the main source of dietary fatty acids in the Mediterranean region. The objective of this study was to evaluate the effect of dietary supplementation with virgin olive oil in an experimental model with rabbits fed an atherogenic diet (saturated fat 48% of total fat). Four different groups of 10 animals each were studied: (1) normolipemic diet (NLD), (2) atherogenic diet or saturated fatty acid-enriched diet (SFAED), (3) NLD with 15% olive oil (NLD+OLIV), and (4) SFAED with 15% virgin olive oil (SFAED+OLIV). The animals were fed the experimental diets for 6 weeks, after which we determined serum lipid profile (total cholesterol, HDL-cholesterol, and triglycerides), platelet aggregation, platelet thromboxane B(2), aortic prostacyclin, and platelet and vascular lipid peroxidation. Scanning electron microscopic images of the vascular endothelium were studied, as were morphometric parameters in the arterial wall and thrombogenicity of the subendothelium (annular perfusion chamber). Animals fed the SFAED showed platelet hyperactivity and increased subendothelial thrombogenicity. Animals fed the SFAED+OLIV showed, compared with the SFAED group, an improved lipid profile with decreased platelet hyperactivity and subendothelial thrombogenicity and less severe morphological lesions of the endothelium and vascular wall. We conclude that supplementation of the SFAED with 15% olive oil reduced vascular thrombogenicity and platelet activation in rabbits. Although the percentage of olive oil in the diet was higher than the amount in the human diet, these results may be helpful in determining the effect of olive oil in the human thrombogenic system.

Isoflavone aglycone-rich extract without soy protein attenuates atherosclerosis development in cholesterol-fed rabbits.

The antiatherogenic effect of soy protein with intact isoflavones is well established, but the effects of isoflavones without soy protein have not been determined. We investigated the antiatherogenic effect of an isoflavone aglycone-rich extract (containing 429.4 mg/g isoflavone aglycones) without soy protein from fermented soy in cholesterol-fed rabbits. We fed 12-wk-old New Zealand white male rabbits diets containing 1 g/100 g cholesterol with 0, 0.33 or 1 g/100 g isoflavone aglycones for 8 wk. We also fed the rabbits a diet containing 1 g/100 g cholesterol with 1.09 g/100 g soy saponin-rich extract, a component other than isoflavone aglycones in the isoflavone aglycone-rich extract. Controls did not consume cholesterol, isoflavone aglycones or saponins. The isoflavone aglycone- and saponin-rich extracts did not affect the serum lipid profile of cholesterol-fed rabbits. The serum concentration of daidzein in its conjugated form was significantly higher in the high isoflavone group than in the low isoflavone group. The level of cholesteryl ester hydroperoxide (ChE-OOH) induced by CuSO(4) in plasma in the high isoflavone group was significantly less than that in the cholesterol group, and the ChE-OOH levels of LDL in the low and high isoflavone groups were significantly less than those in the cholesterol group. The ChE-OOH levels in plasma and LDL in the saponin group did not differ from the cholesterol group. In the aortic arch, the cholesterol concentration was significantly lower in the high isoflavone group, and malondialdehyde concentration was significantly lower in the low and high isoflavone groups compared with the cholesterol group; however these concentrations in the saponin group did not differ from those in the cholesterol group. The atherosclerotic lesion area of the aortic arch was significantly lower in the isoflavone groups (26.3% lower in the low isoflavone group and 36.9% lower in the high isoflavone group) than in the cholesterol group. The lesion areas were not different in the soy saponin and cholesterol groups. Immunohistochemical analysis revealed fewer oxidized LDL-positive macrophage-derived foam cells in atherosclerotic lesions in the aortic arch of isoflavone groups compared with that of the cholesterol group. These results suggest that the antioxidative action of isoflavones and their antioxidative metabolites inhibit the oxidation of LDL, thereby exerting an antiatherosclerotic effect.