Biomedical subjects

M A Lasunción

Publications and source records attributed to M A Lasunción.

At least 19 recordsLinked to original sources

PubMed2006

Saturated fat in the diet of Spanish children: relationship with anthropometric, alimentary, nutritional and lipid profiles.

OBJECTIVE: To compare the anthropometric, alimentary, nutritional and lipid profiles and global diet quality of Spanish children according to saturated fat intake. DESIGN: This was a cross-sectional study. Food data were collected using a food-frequency questionnaire. SUBJECTS AND METHODS: The sample included 1112 children of both sexes, aged between 6 and 7 years, selected by means of random cluster sampling in schools. The plasma lipid profile included measurements of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, apolipoprotein A1 (apoA1) and apolipoprotein B (apoB). Global diet quality was evaluated by the Dietary Variety Index (DVI) and the Healthy Eating Index (HEI). RESULTS: Energy intake, DVI and HEI of children from the lower quartile of saturated fat intake (LL) were higher (P<001) than in the remaining children (UL). However, there were no significant differences in average height or weight between groups. The UL children had lower intakes of meat, fish, vegetables, fruits and olive oil and a higher intake of dairy products (P<0.001). The intakes of fibre, vitamins C, D, B6, E and folic acid were higher in the LL children, who had lower intakes of vitamin A and calcium. The ratios LDL-C/HDL-C and apoB/apoA1 were lower (P=0.04) in the LL children (1.87 and 0.52, respectively) than in the UL children (2.02 and 0.54, respectively). CONCLUSIONS: The growth rate of children does not seem to be affected by the level of saturated fat intake. Furthermore, at the levels of intake observed in this study, diets with less saturated fat are associated with better alimentary, nutritional and plasma lipid profiles.

Anthropometry↗

PubMed2003

Greater dietary variety is associated with better biochemical nutritional status in Spanish children: the Four Provinces Study.

BACKGROUND AND AIM: Although dietary variety has been associated with a better nutritional profile, its possible role in obesity raises doubts about its overall health benefits. In this study, we examined the association between dietary variety and anthropometric variables, food intake and various food intake biomarkers in Spanish children. METHODS AND RESULTS: This was a cross-sectional study of 1112 children aged 6-7 years from Cadiz, Murcia, Orense and Madrid, who were selected by means of the random cluster-sampling of schools. Information concerning food and nutrient intake was obtained using a food frequency questionnaire, and a dietary variety index (DVI) was calculated on the basis of the number of different foods consumed more than once a month. The anthropometric variables (weight and height), and plasma lipid and vitamin levels were determined using standardised methods. Our results show that the body mass index (BMI) did not vary substantially as a function of DVI: it was 16.9 in the lowest DVI tertile and 17.2 in the highest (p=0.20). Unlike BMI, the DVI positively correlated (p<0.05) with the plasma levels of alpha and beta-carotene, lycopene, retinol, alpha-tocopherol and vitamin E, with energy intake, and with most of the foods, particularly vegetables, fruit and sausages (respective correlation coefficients of 0.43, 0.26 and 0.23). CONCLUSIONS: Dietary variety is associated with a better food and nutritional profile in Spanish children. Nevertheless, the presence of a positive association between the DVI and energy intake, and the consumption of sausages and pre-cooked products calls for the recommendation of a varied diet of healthy foods, such as cereals (especially whole grains), fruits and vegetables.

Biomarkers↗

PubMed2002

Influence of apolipoprotein E polymorphism on plasma vitamin A and vitamin E levels.

BACKGROUND: Plasma concentrations of vitamins A and E are positively correlated with those of concurrent lipids and, on the other hand, lipid levels are influenced by apolipoprotein E polymorphism. Therefore, the effect of this polymorphism on both vitamins was analysed in an adult population. MATERIALS AND METHODS: Subjects were recruited from a working population. Their anthropometric, lifestyle and dietary intake variables and menopausal status were recorded. Their apolipoprotein E phenotype and their plasma vitamins A and E (by high-performance liquid chromatography) and lipid (enzymatically) concentrations were determined after an overnight fast. The associations of the phenotype with vitamins and lipids were studied in men and women separately and controlling for significant covariates. RESULTS: The apolipoprotein E phenotype was associated with the concentrations of total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol in women, whereas no associations with lipids were found in men. Vitamin A and vitamin E levels were higher in men than in women, but only the difference in the former persisted after lipid adjustment. Apolipoprotein E2 slightly increased vitamin A levels in women, an effect which was still evident with lipid adjustment. Actually, both the apolipoprotein E phenotype and triglyceride were selected as significant predictors of this vitamin by multiple regression. This phenotype did not affect vitamin E levels in either sex. CONCLUSIONS: Lipids do not mediate the effect of gender on vitamin A levels. Apolipoprotein E polymorphism is an independent determinant of vitamin A levels in women. Pending confirmation by others, we propose that enhancement of this vitamin may contribute to the beneficial impact of the epsilon2 allele on human ageing and health.

Adult↗

PubMed2002

Gender-specific effects of apolipoprotein E genotype on plasma lipid levels in a population-based sample of 6-7-year-old children in Spain.

AIM: The effects of gender on the association between apolipoprotein E genotype and plasma lipid levels remain unclear in children. The aim of the present work was to evaluate these gender differences in a large population-based sample of 6-7-y-old children, free of the effects of sex hormones. METHODS: Lipid levels and apo E genotypes were studied in a sample of 1255 (631 M, 624 F) Caucasian schoolchildren, aged 6-7 (mean age, 6.7) y in Spain. RESULTS: A significant effect of the apo E genotype on plasma total cholesterol, LDL-C (low-density lipoprotein cholesterol) and apo B levels was observed. Taking the homozygous epsilon3epsilon3 genotype as reference, the presence of the epsilon2 and epsilon4 alleles is associated with substantially lower and higher plasma levels, respectively, of these variables. It was found that the effect of the apo E polymorphism on total cholesterol, LDL-C and particularly on apo B levels was greater in girls than in boys. CONCLUSION: At this prepubertal age, the influence of the apo E genotype on total cholesterol, LDL-C and apo B levels is more evident in girls than in boys. This difference in effect is not due to sex hormones. In our opinion, the earlier increase in adrenal androgens in girls than in boys at this age related to pubertal maturation could be responsible for these differences.

Apolipoproteins B↗

PubMed2001

Dose-dependent effects of lovastatin on cell cycle progression. Distinct requirement of cholesterol and non-sterol mevalonate derivatives.

The mevalonate pathway is tightly linked to cell proliferation. The aim of the present study is to determine the relationship between the inhibition of this pathway by lovastatin and the cell cycle. HL-60 and MOLT-4 human cell lines were cultured in a cholesterol-free medium and treated with increasing concentrations of lovastatin, and their effects on cell proliferation and the cell cycle were analyzed. Lovastatin was much more efficient in inhibiting cholesterol biosynthesis than protein prenylation. As a result of this, lovastatin blocked cell proliferation at any concentration used, but its effects on cell cycle distribution varied. At relatively low lovastatin concentrations (less than 10 microM), cells accumulated preferentially in G(2) phase, an effect which was both prevented and reversed by low-density lipoprotein cholesterol. At higher concentrations (50 microM), the cell cycle was also arrested at G(1) phase. In cells treated with lovastatin, those arrested at G(1) progressed through S upon mevalonate provision, whereas cholesterol supply allowed cells arrested at G(2) to traverse M phase. These results demonstrate the distinct roles of mevalonate, or its non-sterol derivatives, and cholesterol in cell cycle progression, both being required for normal cell cycling.

Apoptosis↗

PubMed2000

Treatment of hirsutism with ethinyl estradiol-desogestrel contraceptive pills has beneficial effects on the lipid profile and improves insulin sensitivity.

OBJECTIVE: To evaluate the effects on the lipid pattern and insulin sensitivity of hirsute women of an oral contraceptive pill containing 30 microg of ethinyl estradiol and 150 microg of desogestrel. DESIGN: Prospective clinical study. SETTING: Tertiary care institutional hospital. PATIENT(S): 16 hirsute women. INTERVENTION(S): Women were evaluated at baseline and after receiving six cycles of oral contraceptive therapy. MAIN OUTCOME MEASURE(S): Body mass index (BMI); hirsutism score (nine body areas); serum levels of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein B, lipoprotein(a), and serum adrenal and ovarian androgens; and fasting glucose and insulin concentrations. RESULT(S): The mean serum total, HDL, and LDL cholesterol levels increased after six cycles of oral contraceptive therapy. Levels of HDL cholesterol were < 50 mg/dL in 7 of the 16 patients at baseline; these levels normalized in 4 patients after treatment. Serum total and LDL cholesterol remained within the normal range in all patients before and after therapy. No significant changes were observed in serum triglyceride, apolipoprotein B and lipoprotein(a) concentrations. Fasting insulin levels and insulin resistance as analyzed by homeostasis model assessment were reduced significantly after therapy. No changes in BMI were observed. Administration of oral contraceptive pills signifiCantly reduced the hirsutism score and hyperandrogenemia. CONCLUSION(S): Oral contraceptive pills containing low-dose ethinyl estradiol and desogestrel are effective in controlling hyperandrogenism and hirsutism and ameliorate the abnormal metabolic profile of women with hirsutism.

Adult↗

PubMed2000

Hydroxymethylglutaryl-coenzyme A reductase inhibition stimulates caspase-1 activity and Th1-cytokine release in peripheral blood mononuclear cells.

T cells are prominent components of both early and late atherosclerotic lesions and the role of Th1/Th2 cells subsets in the evolution and rupture of the plaque is currently under investigation. Statins, which are inhibitors of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase, exert actions beyond that of simply lowering cholesterol levels, and some effects on immune function have been reported. We studied in vitro the effects of fluvastatin on Th1/Th2 cytokine release in relation to caspase-1 activation, in human peripheral-blood mononuclear cells (PBMC) stimulated or not with Mycobacterium tuberculosis. Fluvastatin treatment resulted in the activation of caspase-1 and in a small secretion of interleukin (IL)-1beta, IL-18, and IFNgamma (Th1). In the presence of bacteria, the release of these cytokines was highly increased by the statin in a synergistic way. By contrast, production of IL-12, IL-10 and IL-4 were unaffected by the statin. Not only did mevalonate abolish the effects of the statin but it also prevented the caspase-1 activation induced by the bacteria, suggesting the involvement of isoprenoids in the response to M. tuberculosis. It is proposed that inhibition of HMG-CoA reductase may be immunoprotective by enhancing the Th1 response, which has therapeutical potential not only in atherosclerosis but also in infectious diseases.

Caspase 1↗

PubMed2000

Effects of normalization of GH hypersecretion on lipoprotein(a) and other lipoprotein serum levels in acromegaly.

BACKGROUND & AIMS: Lipoprotein(a) has been recognized as an important risk factor for cardiovascular disease. Lipoprotein(a) has been found to be elevated in sera of acromegalic patients, possibly contributing to the increased incidence of coronary heart disease found in these patients. In the present study we sought to determine the effects of GH hormonal status on lipoprotein(a) and other lipid parameters, including lipoprotein lipase (LPL) activity. DESIGN: Cross-sectional study. PATIENTS: Twenty acromegalic patients, with either active (n = 12) or controlled (n = 8) acromegaly, were studied. Twenty-nine healthy subjects served as control group for serum lipid measurements. MEASUREMENTS: Serum GH, IGF-1, IGF binding protein-3 (IGFBP-3) and insulin levels were measured in patients. Insulin resistance was measured by the homeostatic model assessment (HOMA). Plasma total cholesterol, triglycerides, HDL-lipids, apolipoproteins A-I and B, lipoprotein(a) and lipoprotein lipase activity were also measured. RESULTS: The highest lipoprotein(a) levels were observed in patients with active acromegaly, followed by patients with controlled acromegaly, whose lipoprotein(a) concentrations were still significantly higher than those of the control group (means +/- SEM: active acromegaly, 0.67+/-0.13 g/l; controlled acromegaly, 0.41+/-0.12 g/l; controls 0.17+/-0.02 g/l; P<0.05). There were no differences in other lipid and lipoprotein values among the groups. In patients, significant correlations were observed between lipoprotein(a) and basal GH levels (r = 0.56, P<0.02), mean GH levels (r = 0.48, P<0.05) and with insulin resistance estimated by HOMA (r = 0.62, P<0.01). No correlations were found between lipoprotein(a) and IGF-1 or IGFBP-3 levels. CONCLUSIONS: Our present results demonstrate that both active acromegalic patients and those with controlled disease have elevated serum lipoprotein(a) concentrations. The findings might suggest that the present biochemical criteria for cure of acromegaly are not strict enough to result in the normalization of all the undesirable metabolic changes found in this disease, and also that significant cardiovascular risk may persist despite successful treatment of acromegaly.

Acromegaly↗

PubMed2000

Plasma leptin levels in rat mother and offspring during pregnancy and lactation.

The profiles of plasma leptin levels in pregnant and lactating rats and their offspring were determined. The plasma leptin levels increased on days 12 and 20 of gestation and declined on day 21 of gestation, remaining at this level during lactation. These changes were similar for lumbar adipose tissue weight, and a significant correlation was found when both variables were plotted with individual values. During the last 2 days of intrauterine life, the plasma leptin levels in the fetuses were in the same range as in their mothers, declining from day 20 to day 21. On the 1st day of life, the leptin levels increased to decline in suckling newborns after 4 days, remaining stable until day 20 of life. The enhancement in maternal white adipose tissue mass that takes place during pregnancy and its decline around parturition and lactation are proposed to contribute actively to the changes in the plasma leptin profile detected at these stages. Besides the contribution of placental leptin for the fetus and milk leptin for the suckling newborn, it is proposed that brown adipose tissue, which is the first form of adipose tissue that appears during development in the rat, is responsible for most of the changes in plasma leptin levels seen around birth, whereas its later decline could be mediated by the hormonal changes occurring after birth.

Adipose Tissue↗

PubMed1999

Apolipoprotein E polymorphism in men and women from a Spanish population: allele frequencies and influence on plasma lipids and apolipoproteins.

UNLABELLED: The apolipoprotein (apo) E phenotype and its influence on plasma lipid and apolipoprotein levels were determined in men and women from a working population of Madrid, Spain. The relative frequencies of alleles epsilon(2), epsilon(3) and epsilon(4) for the study population (n=614) were 0.080, 0.842 and 0.078, respectively. In men, apo E polymorphism was associated with variations in plasma triglyceride and very low-density lipoprotein (VLDL) lipid levels. It was associated with the proportion of apo C-II in VLDL, and explained 5.5% of the variability in the latter parameter. In women apo E polymorphism was associated with the concentrations of plasma cholesterol and low-density lipoprotein (LDL) and high-density lipoprotein (HDL) related variables. The allelic effects were examined taking allele epsilon(3) homozygosity as reference. In men, allele epsilon(2) significantly increased VLDL triglyceride and VLDL cholesterol concentrations, and this was accompanied by an increase of the apo C-II content in these particles. Allele epsilon(4) did not show any significant influence on men's lipoproteins. In women, allele epsilon(2) lowered LDL cholesterol and apo B levels, while allele epsilon(4) increased LDL cholesterol and decreased the concentrations of HDL cholesterol, HDL phospholipid and apo A-I. These effects were essentially maintained after excluding postmenopausal women and oral contraceptive users from the analysis. IN CONCLUSION: (1) the population of Madrid, similar to other Mediterranean populations, exhibits an underexpression of apo E4 compared to the average prevalence in Caucasians, (2) gender interacts with the effects of apo E polymorphism: in women, it influenced LDL and HDL levels, whereas in men it preferentially affected VLDL, and (3) allele epsilon(2) decreased LDL levels in women, while it increased both VLDL lipid levels and apo C-II content in men, but, in contrast to allele epsilon(4), it did not show an impact on HDL in either sex.

Adult↗

PubMed1999

Impact of different low-density lipoprotein (LDL) receptor mutations on the ability of LDL to support lymphocyte proliferation.

Based on the demand for cholesterol for membrane formation, we determined the ability of low-density lipoprotein (LDL) to support proliferation in lymphocytes bearing different LDL receptor mutations, which were treated "in vitro" with lovastatin to inhibit endogenous cholesterol synthesis. Peripheral lymphocytes were isolated from two patients with homozygous familial hypercholesterolemia (FH), one homozygote for the mutation N804K (FH(Colmenar)) in exon 17, herein described for the first time, and a compound heterozygote carrying the mutations D280G and G528V, which determine a transport-defective biochemical phenotype. Flow cytometric analysis with 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanineperchlorate (Dil)-LDL showed normal LDL binding but defective internalization in lymphocytes from case 1, whereas in lymphocytes from case 2 both LDL binding and internalization were affected. Studies with mitogen-stimulated lymphocytes demonstrated that despite the different phenotype, the ability of LDL to support proliferation was impaired in both cases to a similar extent. These results indicate that internalization of the LDL particle is required for expression of the mitogenic effect of LDL.

Adolescent↗

PubMed1999

[The 4 Provinces Study: its principal objectives and design. The Researchers of the 4 Provinces Study].

INTRODUCTION AND OBJECTIVES: Spain shows an important variation in the geographical distribution of ischaemic heart disease and cerebrovascular disease mortality. In this article, the primary objectives and design of the Four Provinces study are described. In this study we analyzed the contribution of environmental factors (diet, lipid profile and plasma antioxidants), acting in childhood, to explain differences in cardiovascular mortality rates between different provinces in Spain. METHODS: An ecological design was projected in which the units to study were four Spanish provinces with a wide variation in cardiovascular mortality in adulthood. The design compares diet, anthropometric variables and biological markers (particularly plasma lipids and antioxidant levels) in 6-7-year-old children, between the two provinces with the highest cardiovascular mortality rates and the two provinces with the lowest. The information for each province is collected in a cross-sectional manner in a representative sample of children from each province. DISCUSSION: Evidence from the literature concerning Northern European countries suggest the contribution of environmental factors during early age in the development of cardiovascular disease in adulthood. The "Four Provinces" study will provide, for the first time, information about the influence of factors in early childhood of cardiovascular risk in a Mediterranean country. The study will also offer interesting data about food intake during school age in four provinces and it will allow us to estimate values of population of the variables of interest in those provinces.

Antioxidants↗

PubMed1998

Flavonoid-induced ability of minimally modified low-density lipoproteins to support lymphocyte proliferation.

Low-density lipoprotein (LDL) peroxidation appears to be involved in atherogenesis. We studied the ability of minimally modified LDL (MM-LDL) to be used by proliferating lymphocytes and the effects of antioxidant flavonoids on this lipoprotein. MM-LDL were obtained by storing LDL at 4 degrees for 1 month, which resulted in a decrease in lipophilic antioxidants and an increased susceptibility to oxidation when incubated with cells. MM-LDL were not cytotoxic; however, in cells treated with lovastatin that require cholesterol for cell growth, they were much less efficient than fresh LDL in sustaining proliferation as determined by [3H]thymidine incorporation into DNA. Pure quercetin and grape-derived beverages restored proliferation in the presence of MM-LDL and prevented the apoptosis otherwise induced by lovastatin. These effects of flavonoids correlated with their activity in inhibiting LDL peroxidation. The results demonstrate that potent antioxidants, such as flavonoids, protect MM-LDL from lipoperoxidation and preserve their ability to efficiently deliver cholesterol to cells.

Antioxidants↗

PubMed1998

[Familial hypercholesterolemia: molecular identification and characterization of the first compound homozygote in Spain].

Homozygous familial hypercholestrolemia (FH) is a rare genetic disorder (one in 1 million persons) due to two different mutations in the LDL receptor gene (compound homozygous) or, rarely, to the presence of the same mutation in the two aleles. In these patients the absence of a functional LDL receptor produces extreme elevations of plasma cholesterol levels that need an aggressive and expensive treatment with LDL apheresis or hepatic transplantation. The clinical evolution is poor with early coronary heart disease. Molecular biology techniques allow a genetic diagnosis and a genetic counseling in the affected subjects. We have identified and characterized the first compound homozygous of FH in Spain using the single strand conformational polymorphism (SSCP) analysis. The patient is a 30 years old female, who carried two different mutations in the LDL receptor gene: the G528V and the D280G (a new mutation). These mutations produce significant changes in the aminoacid sequence and could be classified as class 2.

Adult↗

PubMed1998

Induction of apoptosis in p53-null HL-60 cells by inhibition of lanosterol 14-alpha demethylase.

To determine the role of cholesterol deprivation in cell proliferation and, eventually, in apoptosis, HL-60 promyelocytic cells were incubated in a cholesterol-depleted medium in the presence of SKF 104976, a specific inhibitor of lanosterol 14-alpha demethylase. As expected, SKF 104976 efficiently blocked the [14C]-acetate incorporation into cholesterol, whereas it induced the accumulation of both lanosterol and, especially, dihydrolanosterol. As a consequence, cell proliferation was greatly depressed at 24 h of treatment with the drug, and clear signs of apoptosis--annexin V binding, condensed and fragmented nuclei and DNA ladder--were observed thereafter. Provided that the HL-60 cell line does not express p53, it may be concluded that apoptosis induced by cholesterol deprivation is not dependent on this tumor suppressor protein. Supplementing the incubation medium with LDL-cholesterol or pure free cholesterol, fully prevented cell growth inhibition and apoptosis induction, whereas mevalonate was ineffective. These results indicate that cholesterol plays a specific role in cell proliferation, a function that is not shared by its precursors lanosterol and dihydrolanosterol.

Apoptosis↗

PubMed1998

Human CD36 is a high affinity receptor for the native lipoproteins HDL, LDL, and VLDL.

Mouse and hamster SR-BI glycoproteins and their putative human counterpart CLA-I are so far the only scavenger receptors known to bind both native and modified lipoproteins. CD36, a multigland glycoprotein structurally related to SR-BI and CLA-1, has been reported to bind oxidized low density lipoprotein (OxLDL) and acetylated LDL (AcLDL). In this report, we have studied the ability of CD36 to bind native lipoproteins. By transient expression of human CD36 in mammalian and insect cells, we demonstrate that CD36 is a high affinity receptor for the native lipoproteins HDL, LDL, VLDL, and, as previously reported, for OxLDL and AcLDL. The specificity of these interactions is supported by the dose-dependent inhibiton, effect of a monoclonal antibody against CD36. Furthermore, at least for HDL, binding to CD36 does not require the presence of apoE. These findings, together with preferential expression of CD36 in tissues performing very active fatty acid metabolism (skeletal muscle, heart, mammary epithelium, and adipose tissue) and its involvement in foam cell formation (macrophages), suggest that binding of lipoproteins to CD36 might contribute to the regulation of lipid metabolism, and to the pathogenesis of atherosclerosis.

Animals↗

PubMed1998

Relationship between serum parathyroid hormone levels and lipid profile in hemodialysis patients. Evolution of lipid parameters after parathyroidectomy.

To determine the influence of parathyroid hormone (PTH) on lipid disturbances of uremia, the lipid profile was determined in 34 hemodialysis (HD) patients, comparing lipid parameters among subjects classified according to their intact PTH level. Furthermore, the effect of correction of severe secondary hyperparathyroidism on serum lipids was evaluated in 7 patients after parathyroidectomy. Total cholesterol, high-density lipoproteins (HDL), triglycerides, apolipoproteins A-I and B-100 (Apo B and Apo B), lipoprotein(a) and the ratios of cholesterol/HDL and Apo A/Apo B were analyzed. There was no correlation between serum lipids and PTH levels in the total group. Lipid profile was similar among patients classified according to their PTH level. No correlations were observed in either group between lipids and PTH. Lipid profile did not change in the seven patients with severe secondary hyperparathyroidism after parathyroidectomy. In conclusion, there was no relationship between PTH and lipids and risk ratios in HD patients. Lipid profile did not change in patients with severe secondary hyperparathyroidism after parathyroidectomy. These findings suggest that PTH does not play a significant role in the dyslipidemia of renal failure.

Adult↗

PubMed1997

LDL from aerobically-trained subjects shows higher resistance to oxidative modification than LDL from sedentary subjects.

We studied the effect of regular intense aerobic exercise on the LDL susceptibility to oxidation and the electronegative LDL-proportion (LDL(-)). A group of 38 well-trained athletes was compared to a group of 38 age-BMI-matched sedentary individuals. Athletes showed higher concentration of total cholesterol (athletes 5.08 +/- 0.70 versus controls 4.65 +/- 0.75 mmol/l, P = 0.0229) and HDL cholesterol (athletes 1.72 +/- 0.47 versus controls 1.46 +/- 0.39 mmol/l, P = 0.0068); total plasma triglyceride, LDL cholesterol and VLDL cholesterol did not differ between trained and untrained subjects. The susceptibility of LDL to oxidation, determined by conjugated dienes formation and expressed as lag phase, was lower in athletes than in sedentaries (trained subjects 47.0 +/- 5.6 versus sedentary subjects 41.9 +/- 5.0 min, P = 0.0002). LDL(-) was similar in both groups (athletes 10.32 +/- 4.70 versus controls 10.26 +/- 3.71%). The antioxidant content in total plasma and isolated LDL (alpha-tocopherol, retinol, lycopene, alpha-carotene and beta-carotene) was quantitated by HPLC in a subgroup of 32 athletes and 32 control subjects. Athletes showed higher amounts of alpha-tocopherol and retinol in plasma, but not in LDL. However, none of these antioxidants correlated with the lag phase time. Trained subjects showed lower prevalence of smoking. However, no differences were observed between smokers and non-smokers concerning lag phase. No significant difference between athletes and sedentaries concerning LDL density, or composition was observed. We conclude that LDL from trained subjects is more resistant to oxidative modification than LDL from sedentary subjects. This observation could not be attributed to conventional antioxidants as alpha-tocopherol and carotene content of LDL was unchanged in trained subjects. Thus, although none of the variables studied appear as a single predictor of the LDL susceptibility to oxidation, an additive effect of the antioxidant content, the presence of some undetermined co-antioxidant, HDL and/or smoking habits cannot be discarded as responsible for the increased resistance to oxidation of LDL in trained subjects.

Adult↗