Beneficial changes on plasma apolipoproteins A and B, high density lipoproteins and oxidized low density lipoproteins in obese women after bariatric surgery: comparison between gastric bypass and sleeve gastrectomy.

BACKGROUND: The beneficial effects in lipid profiles after obesity surgery might be associated with the decrease in cardiovascular risk. However, direct comparison between different surgical techniques has not been extensively performed. METHODS: In the present study we compare 20 obese women submitted to laparoscopic Roux en Y gastric bypass (RYGB) with 20 women submitted to sleeve gastrectomy (SG). Twenty control women matched for age and baseline cardiovascular risk were also included. Both patients and controls were followed up for 1 year after surgery or conventional treatment with diet and exercise, respectively. Lipid profiles were measured at baseline, 6 and 12 months later. Carotid intima-media thickness was measured by ultrasonography at baseline and at the end of the study. RESULTS: Women submitted to bariatric surgery showed a decrease in total cholesterol, triglycerides, oxidized-LDL and ApoB, and an increase in HDL and ApoA concentrations that occurred regardless of the surgical procedure. LDL concentrations, however, decreased only after RYGB whereas Lp(a) showed no changes. We did not observe any correlation between the changes in serum lipid concentrations and those in carotid intima-media thickness. CONCLUSIONS: Sleeve gastrectomy and gastric bypass induce a similar beneficial effect on serum lipids in women with high cardiovascular risk 1 year after surgery.

Liver growth factor induces testicular regeneration in EDS-treated rats and increases protein levels of class B scavenger receptors.

The aim of the present work was to determine the effects of liver growth factor (LGF) on the regeneration process of rat testes after chemical castration induced by ethane dimethanesulfonate (EDS) by analyzing some of the most relevant proteins involved in cholesterol metabolism, such as hormone sensitive lipase (HSL), 3ß-hydroxysteroid dehydrogenase (3ß-HSD), scavenger receptor SR-BI, and other components of the SR family that could contribute to the recovery of steroidogenesis and spermatogenesis in the testis. Sixty male rats were randomized to nontreated (controls) and LGF-treated, EDS-treated, and EDS + LGF-treated groups. Testes were obtained on days 10 (T1), 21 (T2), and 35 (T3) after EDS treatment, embedded in paraffin, and analyzed by immunohistochemistry and Western blot. LGF improved the recovery of the seminiferous epithelia, the appearance of the mature pattern of Leydig cell interstitial distribution, and the expression of mature SR-BI. Moreover, LGF treatment resulted in partial recovery of HSL expression in Leydig cells and spermatogonia. No changes in serum testosterone were observed in control or LGF-treated rats, but in EDS-castrated animals LGF treatment induced a progressive increase in serum testosterone levels and 3ß-HSD expression. Based on the pivotal role of SR-BI in the uptake of cholesteryl esters from HDL, it is suggested that the observed effects of LGF would facilitate the provision of cholesterol for sperm cell growth and Leydig cell recovery.

Clinically used selective oestrogen receptor modulators increase LDL receptor activity in primary human lymphocytes.

BACKGROUND AND PURPOSE: Treatment with selective oestrogen receptor modulators (SERMs) reduces low-density lipoprotein (LDL) cholesterol levels. We assessed the effect of tamoxifen, raloxifene and toremifene and their combinations with lovastatin on LDL receptor activity in lymphocytes from normolipidaemic and familial hypercholesterolaemic (FH) subjects, and human HepG2 hepatocytes and MOLT-4 lymphoblasts. EXPERIMENTAL APPROACH: Lymphocytes were isolated from peripheral blood, treated with different compounds, and 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanine perchlorate (DiI)-labelled LDL uptake was analysed by flow cytometry. KEY RESULTS: Tamoxifen, toremifene and raloxifene, in this order, stimulated DiI-LDL uptake by lymphocytes by inhibiting LDL-derived cholesterol trafficking and subsequent down-regulation of LDL receptor expression. Differently to what occurred in HepG2 and MOLT-4 cells, only tamoxifen consistently displayed a potentiating effect with lovastatin in primary lymphocytes. The SERM-mediated increase in LDL receptor activity was not altered by the anti-oestrogen ICI 182,780 nor was it reproduced by 17ß-oestradiol. However, the tamoxifen-active metabolite endoxifen was equally effective as tamoxifen. The SERMs produced similar effects on LDL receptor activity in heterozygous FH lymphocytes as in normal lymphocytes, although none of them had a potentiating effect with lovastatin in heterozygous FH lymphocytes. The SERMs had no effect in homozygous FH lymphocytes. CONCLUSIONS AND IMPLICATIONS: Clinically used SERMs up-regulate LDL receptors in primary human lymphocytes. There is a mild enhancement between SERMs and lovastatin of lymphocyte LDLR activity, the potentiation being greater in HepG2 and MOLT-4 cells. The effect of SERMs is independent of oestrogen receptors but is preserved in the tamoxifen-active metabolite endoxifen. This mechanism may contribute to the cholesterol-lowering action of SERMs.

Hormone-sensitive lipase deficiency disturbs the fatty acid composition of mouse testis.

Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from intracellular stores. In mice, HSL deficiency results in male sterility caused by a major defect in spermatogenesis. The testes contain high concentrations of PUFA and specific PUFA are essential for spermatogenesis. We investigated the fatty acid composition and the mRNA levels of key enzymes involved in fatty acid metabolism in testis of HSL-knockout mice. HSL deficiency altered fatty acid composition in the testis but not in plasma. The most important changes were decreases in the essential n-6 PUFA LNA and the n-3 PUFA ALA, and an increase in the corresponding synthesis intermediates C22:4n-6 and C22:5n-3 without changes in DPAn-6 or DHA acids. Mead acid, which has been associated with an essential fatty acid deficit leading to male infertility, was increased in the testis from HSL-knockout mice. Moreover, the expression of SCD-1, FADS1, and FADS2 was increased while expression of ELOVL2, an essential enzyme for the formation of very-long PUFA in testis, was decreased. Given the indispensability of these fatty acids for spermatogenesis, the changes in fatty acid metabolism observed in testes from HSL-knockout male mice may underlie the infertility of these animals.

Haloperidol disrupts lipid rafts and impairs insulin signaling in SH-SY5Y cells.

Haloperidol exerts its therapeutic effects basically by acting on dopamine receptors. We previously reported that haloperidol inhibits cholesterol biosynthesis in cultured cells. In the present work we investigated its effects on lipid-raft composition and functionality. In both neuroblastoma SH-SY5Y and promyelocytic HL-60 human cell lines, haloperidol inhibited cholesterol biosynthesis resulting in a decrease of the cell cholesterol content and the accumulation of different sterol intermediates (7-dehydrocholesterol, zymostenol and cholesta-8,14-dien-3beta-ol) depending on the dose of the drug. As a consequence, the cholesterol content in lipid rafts was greatly reduced, and several pre-cholesterol sterols, particularly cholesta-8,14-dien-3beta-ol, were incorporated into the cell membrane. This was accompanied by the disruption of lipid rafts, with redistribution of flotillin-1 and Fyn and the impairment of insulin-Akt signaling. Supplementing the medium with free cholesterol abrogated the effects of haloperidol on lipid-raft composition and functionality. LDL (low-density lipoprotein), a physiological vehicle of cholesterol in plasma, was much less effective in preventing the effects of haloperidol, which is attributed to the drug's inhibition of intracellular vesicular trafficking. These effects on cellular cholesterol homeostasis that ultimately result in the alteration of lipid-raft-dependent insulin signaling action may underlie some of the metabolic effects of this widely used antipsychotic.

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.

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.

A double mutant [N543H+2393del9] allele in the LDL receptor gene in familial hypercholesterolemia: effect on plasma cholesterol levels and cardiovascular disease.

Familial hypercholesterolemia is a genetic disorder caused by mutations in the LDL receptor gene. During a survey of mutations of LDL receptor gene in Spanish FH patients we found two mutations in the same allele: a missense N543H mutation in exon 11 and a 9bp inframe deletion (2393del9) located in exon 17. This double mutant allele was founded in 10 out of 458 unrelated patients: one homozygous FH [N543H+2393del9] + [N543H+2393del9], one compound heterozygote [N543H+2393del9] + [W-18X+E256K] and 8 heterozygotes. Flow cytometric analysis showed a defective LDL binding (20% of normal value) and internalization (23%) in lymphocytes from the homozygous patient; furthermore, studies of mitogen-stimulated lymphocytes demonstrated that the ability of LDL to support cell proliferation was impaired. Unexpectedly, not all carriers of the double mutant allele develop hypercholesterolemia and, furthermore, cholesterol-lowering treatment of the homozygous patient resulted in a 58% LDL cholesterol reduction. In conclusion, the phenotypic expression in the homozygous and heterozygous patients presented here, as well as the LDL-receptor residual activity, allowed the classification of this mutation as mild extending the group of mild mutations found at homozygosity.

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.

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.

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.

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.

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.

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.

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.

Improvement in lipid and haemostasis patterns after Helicobacter pylori infection eradication in type 1 diabetic patients.

Helicobacter pylori has been implicated in the cardiovascular risk of diabetic patients. The aim of our study was to investigate whether the Helicobacter pylori infection plays a role in the lipid and haemostasis patterns of type 1 diabetic patients. Twenty nine patients with type 1 diabetes mellitus and H. pylori infection were enrolled (Chlamydia pneumoniae negative). The H. pylori infection status was assessed by serology and urease breath test. In all patients levels of total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol, lipoprotein (a) (Lpa) C reactive protein (CRP), fibrinogen, thrombin/antithrombin III complex (TAT), plasminogen activator inhibitor type 1(PAI-1), tissue plasminogen activator (t-PA) and von Willebrand antigen were measured. All patients were evaluated before and after H. pylori eradicating treatment with amoxicillin, clarithromycin and omeprazole. Twenty two patients were eradicated and seven remained infected. In H. pylori eradicated patients, HDL cholesterol increased (59.7+/-18.9 mg/dl vs 65.2+/-15. 9 mg/dl, P << 0.05), after treatment. After H. pylori eradication, the levels of CRP and TAT decreased (48+/-0.7 ng/l vs 3.3+/-0.4 ng/l;P << 0.05), (27.7+/-44.7 microg/ml vs 2.1+/-1.4 microg/ml, P << 0.05), respectively. The decrease in TAT was higher in the group of H. pylori (+) patients with higher levels of TAT (TAT >> 20 ng/ml, 92.8+/-41.6 ng/ml vs 1.9+/-2.0 ng/ml, P << 0.005; TAT 4Eth 20 ng/ml; 10.1+/-5.2 ng/ml vs 2.2+/-0.6 ng/ml, P << 0.05). These changes did not occur in patients without H. pylori eradication. Eradication of H. pylori infection in type 1 diabetic patients modifies some parameters of lipid and haemostasis patterns, (increase of HDL-cholesterol, reduction of Lpa and decrease of CRP and TAT) and so contributes to improvement of cardiovascular risk factors in these patients.

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.

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.

Cholesterol starvation decreases p34(cdc2) kinase activity and arrests the cell cycle at G2.

As a major component of mammalian cell plasma membranes, cholesterol is essential for cell growth. Accordingly, the restriction of cholesterol provision has been shown to result in cell proliferation inhibition. We explored the potential regulatory role of cholesterol on cell cycle progression. MOLT-4 and HL-60 cell lines were cultured in a cholesterol-deficient medium and simultaneously exposed to SKF 104976, which is a specific inhibitor of lanosterol 14-alpha demethylase. Through HPLC analyses with on-line radioactivity detection, we found that SKF 104976 efficiently blocked the [(14)C]-acetate incorporation into cholesterol, resulting in an accumulation of lanosterol and dihydrolanosterol, without affecting the synthesis of mevalonic acid. The inhibitor also produced a rapid and intense inhibition of cell proliferation (IC(50) = 0.1 microM), as assessed by both [(3)H]-thymidine incorporation into DNA and cell counting. Flow cytometry and morphological examination showed that treatment with SKF 104976 for 48 h or longer resulted in the accumulation of cells specifically at G2 phase, whereas both the G1 traversal and the transition through S were unaffected. The G2 arrest was accompanied by an increase in the hyperphosphorylated form of p34(cdc2) and a reduction of its activity, as determined by assaying the H1 histone phosphorylating activity of p34(cdc2) immunoprecipitates. The persistent deficiency of cholesterol induced apoptosis. However, supplementing the medium with cholesterol, either in the form of LDL or free cholesterol dissolved in ethanol, completely abolished these effects, whereas mevalonate was ineffective. Caffeine, which abrogates the G2 checkpoint by preventing p34(cdc2) phosphorylation, reduced the accumulation in G2 when added to cultures containing cells on transit to G2, but was ineffective in cells arrested at G2 by sustained cholesterol starvation. Cells arrested in G2, however, were still viable and responded to cholesterol provision by activating p34(cdc2) and resuming the cell cycle. We conclude that in both lymphoblastoid and promyelocytic cells, cholesterol availability governs the G2 traversal, probably by affecting p34(cdc2) activity.

[The 4 Provinces Study: its principal objectives and design. The Researchers of the 4 Provinces Study]. / Estudio Cuatro Provincias: principales objectivos y diseño. Investigadores del Estudio Cuatro Provincias.

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.