Biomedical subjects

Isabel Núñez

Publications and source records attributed to Isabel Núñez.

5 recordsLinked to original sources

PubMed2006

Acute effects of high-fat meals enriched with walnuts or olive oil on postprandial endothelial function.

OBJECTIVES: We sought to investigate whether the addition of walnuts or olive oil to a fatty meal have differential effects on postprandial vasoactivity, lipoproteins, markers of oxidation and endothelial activation, and plasma asymmetric dimethylarginine (ADMA). BACKGROUND: Compared with a Mediterranean diet, a walnut diet has been shown to improve endothelial function in hypercholesterolemic patients. We hypothesized that walnuts would reverse postprandial endothelial dysfunction associated with consumption of a fatty meal. METHODS: We randomized in a crossover design 12 healthy subjects and 12 patients with hypercholesterolemia to 2 high-fat meal sequences to which 25 g olive oil or 40 g walnuts had been added. Both test meals contained 80 g fat and 35% saturated fatty acids, and consumption of each meal was separated by 1 week. Venipunctures and ultrasound measurements of brachial artery endothelial function were performed after fasting and 4 h after test meals. RESULTS: In both study groups, flow-mediated dilation (FMD) was worse after the olive oil meal than after the walnut meal (p = 0.006, time-period interaction). Fasting, but not postprandial, triglyceride concentrations correlated inversely with FMD (r = -0.324; p = 0.024). Flow-independent dilation and plasma ADMA concentrations were unchanged, and the concentration of oxidized low-density lipoproteins decreased (p = 0.051) after either meal. The plasma concentrations of soluble inflammatory cytokines and adhesion molecules decreased (p < 0.01) independently of meal type, except for E-selectin, which decreased more (p = 0.033) after the walnut meal. CONCLUSIONS: Adding walnuts to a high-fat meal acutely improves FMD independently of changes in oxidation, inflammation, or ADMA. Both walnuts and olive oil preserve the protective phenotype of endothelial cells.

Brachial Artery↗

PubMed2006

Influence of HDL cholesterol on preclinical carotid atherosclerosis in familial hypercholesterolemia.

OBJECTIVE: The effect of risk factors on carotid atherosclerosis in heterozygous familial hypercholesterolemia (FH) is unclear. We evaluated carotid intima-media thickness (IMT) by sonography in relation to classical and emergent risk factors in a large FH cohort. METHODS AND RESULTS: Risk factors and carotid IMT were assessed in 196 asymptomatic subjects aged > or =25 years fulfilling strict diagnostic criteria for clinical FH who were either undertreated or treatment-naive. Conventional risk factors, but not lipoprotein(a), homocysteine, or apolipoprotein E (apoE) genotypes were univariately related to IMT. Age-adjusted and gender-adjusted IMT increased with increasing low-density lipoprotein (LDL) cholesterol and decreased with increasing high-density lipoprotein (HDL) cholesterol. Compared with a total cholesterol/HDL ratio >5.0, a ratio < or =5.0 was associated with a lower adjusted IMT, with a mean difference of -0. 09 mm (95% confidence interval, -0.13 to -0.04). By multivariate analysis, age, HDL cholesterol (negatively), physical exercise, family history of early-onset coronary heart disease, LDL cholesterol, and leukocyte count, in this order, were independent associations of IMT (r2=0.429, P<0.001). CONCLUSIONS: Traditional risk factors account for a sizeable proportion of variation in carotid IMT in FH. Because the HDL cholesterol level and the total cholesterol/HDL ratio are strong predictors of preclinical carotid atherosclerosis, HDL cholesterol-raising strategies should have an important therapeutic role in FH.

Adult↗

PubMed2005

[Carotid ultrasound in the assessment of preclinical atherosclerosis. Distribution of intima-media thickness values and plaque frequency in a Spanish community cohort].

BACKGROUND AND OBJECTIVE: High-resolution B-mode ultrasound measurements of carotid intima-media thickness (IMT) and determination of plaque presence are useful to assess preclinical atherosclerosis. Normal IMT values have not been reported in Spanish subjects. Our aim was to define normality data of carotid ultrasound by sex and age. SUBJECTS AND METHODS: We studied 250 healthy, normolipidemic subjects, 125 men and 125 women, with mean age 49 years (range, 20-81). We assessed cardiovascular risk factors and performed ultrasound determination of mean and maximum IMT in the far wall of the common carotid artery, plaque occurrence, and maximum plaque height. RESULTS: Reference values for carotid IMT, expressed as 25th, 50th, and 75th percentiles by sex and 5 age groups, have been obtained. The 50th percentiles of mean IMT ranged from 0.50 to 0.74 mm in men in the age groups 35 years or younger and 65 years or older, respectively. For women, corresponding IMT values ranged from 0.40 to 0.65 mm. IMT was strongly related (p < 0.001) to age, both in men (r = 0.57) and women (r = 0.61). From the regression equations, the estimated yearly increase in IMT was 0.005 mm in men and 0.007 mm in women. More than 50% of men aged 55 years and older, and of women aged 65 years and older, had carotid plaques. CONCLUSIONS: Both IMT and plaque frequency were associated with age in men and women. Carotid IMT values in a Spanish community cohort were lower than those reported for countries with higher cardiovascular risk, such as Northern European countries and the US.

Adult↗

PubMed2005

The use of Achilles tendon sonography to distinguish familial hypercholesterolemia from other genetic dyslipidemias.

OBJECTIVE: Achilles tendon (AT) xanthomas, specific for familial hypercholesterolemia (FH), may be clinically undetectable. We assessed the usefulness of AT sonography in the diagnosis of FH. METHODS AND RESULTS: Sonographic AT characteristics were evaluated in 127 subjects with FH (81 genetically ascertained), 84 familial combined hyperlipidemia, 79 polygenic hypercholesterolemia, and 88 normolipidemic controls. Abnormal echostructure (sonographic xanthoma) was noted only in FH. AT thickness was higher (P<0.001) in FH men and women compared with all of the other groups and, in FH mutation carriers but not in others, correlated positively with low-density lipoprotein cholesterol (r=0.345; P<0.001) and negatively with high-density lipoprotein cholesterol (r=-0.265, P=0.015). Thickness thresholds for the diagnosis of FH with specificity >80%, as were derived from receiver operating curves, were 5.3 and 5.7 mm in men < and >45 years, and 4.8 and 4.9 mm in women < and >50 years, respectively. In FH mutation carriers, sonographic findings increased the clinical diagnosis of xanthomas from 35 (43%) to 55 (68%). Using thresholds in validation sets of 70 genetically identified FH and 54 dyslipidemic non-FH correctly classified 80% and 88%, respectively. CONCLUSIONS: Sonographic AT characteristics are normal in non-FH dyslipidemias. Identification of suspected FH by ultrasound using sex- and age-specific AT thickness thresholds is recommended.

Achilles Tendon↗

PubMed2004

A walnut diet improves endothelial function in hypercholesterolemic subjects: a randomized crossover trial.

BACKGROUND: Epidemiological studies suggest that nut intake decreases coronary artery disease (CAD) risk. Nuts have a cholesterol-lowering effect that partly explains this benefit. Endothelial dysfunction is associated with CAD and its risk factors and is reversed by antioxidants and marine n-3 fatty acids. Walnuts are a rich source of both antioxidants and alpha-linolenic acid, a plant n-3 fatty acid. METHODS AND RESULTS: To test the hypothesis that walnut intake will reverse endothelial dysfunction, we randomized in a crossover design 21 hypercholesterolemic men and women to a cholesterol-lowering Mediterranean diet and a diet of similar energy and fat content in which walnuts replaced approximately 32% of the energy from monounsaturated fat. Participants followed each diet for 4 weeks. After each intervention, we obtained fasting blood and performed ultrasound measurements of brachial artery vasomotor function. Eighteen subjects completing the protocol had suitable ultrasound studies. Compared with the Mediterranean diet, the walnut diet improved endothelium-dependent vasodilation and reduced levels of vascular cell adhesion molecule-1 (P<0.05 for both). Endothelium-independent vasodilation and levels of intercellular adhesion molecule-1, C-reactive protein, homocysteine, and oxidation biomarkers were similar after each diet. The walnut diet significantly reduced total cholesterol (-4.4+/-7.4%) and LDL cholesterol (-6.4+/-10.0%) (P<0.05 for both). Cholesterol reductions correlated with increases of both dietary alpha-linolenic acid and LDL gamma-tocopherol content, and changes of endothelium-dependent vasodilation correlated with those of cholesterol-to-HDL ratios (P<0.05 for all). CONCLUSIONS: Substituting walnuts for monounsaturated fat in a Mediterranean diet improves endothelium-dependent vasodilation in hypercholesterolemic subjects. This finding might explain the cardioprotective effect of nut intake beyond cholesterol lowering.

Adult↗