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Background: According to epidemiological studies, there is no clear relationship between the plasma cholesteryl ester transfer protein (CETP) concentration and the development of atherosclerosis in human populations. Although some studies suggest that increased CETP activity relates to undesirable profiles of plasma lipoproteins, promoting an anti-atherogenic plasma lipoprotein profile by drugs that inhibit CETP has not succeeded in preventing atherosclerosis in humans., Materials and Methods: This review describes 28 investigations in human populations dealing with plasma CETP, 11 in mice that express human CETP and seven in animals (six in rabbits and one in mice) in which plasma CETP activity was inhibited by drugs., Results: Present review shows that models in mice expressing human CETP are not illuminating because they report increase as well reduction of atherosclerosis. However, investigations in rabbits and mice that develop severe hypercholesterolaemia clearly indicate that impairment of the plasma CETP activity elicits protection against the development of atherosclerosis; in all of these experiments are attained substantial reductions of the atherogenic lipoproteins, namely, plasma apoB containing lipoproteins., Conclusion: These models are strong indicators that the benefit in preventing atherosclerosis should be earned in cases of hyperlipidemia by CETP inhibitors., (© 2016 Stichting European Society for Clinical Investigation Journal Foundation.)

Considering the growing knowledge and perspectives on microRNAs (miRNAs) that control high-density lipoprotein cholesterol (HDL-C) levels and metabolism, this study aimed at evaluating whether hsa-miR-33a and hsa-miR-128a are differentially expressed in peripheral blood mononuclear cells from asymptomatic individuals with low and high HDL-C, as well as at investigating the potential relationships with ATP binding cassete transporter A1 (ABCA1) expression, cholesterol efflux capacity and other parameters related with reverse cholesterol transport. In addition, the associations with cardiovascular risk were investigated by carotid-intima media thickness (cIMT). Asymptomatic volunteers of both genders (n=51) were classified according to HDL-C (mg/dL) in hypoalphalipoproteinemics (hypo, HDL-C ≤3 9), hyperalphalipoproteinemics (hyper, HDL-C ≥ 68) and controls (CTL, HDL-C ≥ 40<68). cIMT, lipids, lipoproteins, HDL size and volume, C reactive protein and insulin were determined, as well as the activities of several proteins and enzymes related to HDL metabolism. In a subgroup of 19 volunteers the cellular cholesterol efflux and HDL composition were determined. Total RNA was extracted from peripheral blood mononuclear cells for relative quantification experiments. Hypo volunteers presented significantly higher levels of triglycerides, VLDL-C and insulin; in addition, HDL size and volume decreased when compared with CTL and hyper. Regarding gene expression analysis, the hyper group presented a decrease of 72% in hsa-miR-33a and higher mRNA expression of ABCA1 and ABCG1 when compared with CTL. No significant differences in hsa-miR-128a expression, cholesterol efflux, cIMT or plaques were found. Further studies are necessary to elucidate the mechanisms underlying the complex miRNA network, regulating cellular cholesterol homeostasis in humans and its clinical repercussions., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Evidences suggest that paraoxonase 1 (PON1) confers important antioxidant and anti-inflammatory properties when associated with high-density lipoprotein (HDL)., Objective: To investigate the relationships between p.Q192R SNP of PON1, biochemical parameters and carotid atherosclerosis in an asymptomatic, normolipidemic Brazilian population sample., Methods: We studied 584 volunteers (females n = 326, males n = 258; 19-75 years of age). Total genomic DNA was extracted and SNP was detected in the TaqMan® SNP OpenArray® genotyping platform (Applied Biosystems, Foster City, CA). Plasma lipoproteins and apolipoproteins were determined and PON1 activity was measured using paraoxon as a substrate. High-resolution β-mode ultrasonography was used to measure cIMT and the presence of carotid atherosclerotic plaques in a subgroup of individuals (n = 317)., Results: The presence of p.192Q was associated with a significant increase in PON1 activity (RR = 12.30 (11.38); RQ = 46.96 (22.35); QQ = 85.35 (24.83) μmol/min; p < 0.0001), HDL-C (RR= 45 (37); RQ = 62 (39); QQ = 69 (29) mg/dL; p < 0.001) and apo A-I (RR = 140.76 ± 36.39; RQ = 147.62 ± 36.92; QQ = 147.49 ± 36.65 mg/dL; p = 0.019). Stepwise regression analysis revealed that heterozygous and p.192Q carriers influenced by 58% PON1 activity towards paraoxon. The univariate linear regression analysis demonstrated that p.Q192R SNP was not associated with mean cIMT; as a result, in the multiple regression analysis, no variables were selected with 5% significance. In logistic regression analysis, the studied parameters were not associated with the presence of carotid plaques., Conclusion: In low-risk individuals, the presence of the p.192Q variant of PON1 is associated with a beneficial plasma lipid profile but not with carotid atherosclerosis.

Background: Current data indicate that the size of high-density lipoprotein (HDL) may be considered an important marker for cardiovascular disease risk. We established reference values of mean HDL size and volume in an asymptomatic representative Brazilian population sample (n=590) and their associations with metabolic parameters by gender., Methods: Size and volume were determined in HDL isolated from plasma by polyethyleneglycol precipitation of apoB-containing lipoproteins and measured using the dynamic light scattering (DLS) technique., Results: Although the gender and age distributions agreed with other studies, the mean HDL size reference value was slightly lower than in some other populations. Both HDL size and volume were influenced by gender and varied according to age. HDL size was associated with age and HDL-C (total population); non- white ethnicity and CETP inversely (females); HDL-C and PLTP mass (males). On the other hand, HDL volume was determined only by HDL-C (total population and in both genders) and by PLTP mass (males)., Conclusions: The reference values for mean HDL size and volume using the DLS technique were established in an asymptomatic and representative Brazilian population sample, as well as their related metabolic factors. HDL-C was a major determinant of HDL size and volume, which were differently modulated in females and in males., (Copyright © 2015 Elsevier B.V. All rights reserved.)

ATP binding cassette transporter G1 (ABCG1) promotes lipidation of nascent high-density lipoprotein (HDL) particles, acting as an intracellular transporter. SNP rs1893590 (c.-204A > C) of ABCG1 gene has been previously studied and reported as functional over plasma HDL-C and lipoprotein lipase activity. This study aimed to investigate the relationships of SNP rs1893590 with plasma lipids and lipoproteins in a large Brazilian population. Were selected 654 asymptomatic and normolipidemic volunteers from both genders. Clinical and anthropometrical data were taken and blood samples were drawn after 12 h fasting. Plasma lipids and lipoproteins, as well as HDL particle size and volume were determined. Genomic DNA was isolated for SNP rs1893590 detection by TaqMan(®) OpenArray(®) Real-Time PCR Plataform (Applied Biosystems). Mann-Whitney U, Chi square and two-way ANOVA were the used statistical tests. No significant differences were found in the comparison analyses between the allele groups for all studied parameters. Conversely, significant interactions were observed between SNP and age over plasma HDL-C, were volunteers under 60 years with AA genotype had increased HDL-C (p = 0.048). Similar results were observed in the group with body mass index (BMI) < 25 kg/m(2), where volunteers with AA genotype had higher HDL-C levels (p = 0.0034), plus an increased HDL particle size (p = 0.01). These findings indicate that SNP rs1893590 of ABCG1 has a significant impact over HDL-C under asymptomatic clinical conditions in an age and BMI dependent way.

Introduction: Cholesterol undergoes oxidation via both enzymatic stress- and free radical-mediated mechanisms, generating a wide range of oxysterols. In contrast to oxidative stress-driven metabolites, enzymatic stress-derived oxysterols are scarcely studied in their association with atherosclerotic disease in humans., Methods: 24S-hydroxycholesterol (24S-HC), 25-hydroxycholesterol (25-HC), and 27-hydroxycholesterol (27-HC) were assessed in plasma and arteries with atherosclerotic plaques from 10 patients (54-84 years) with severe peripheral artery disease (PAD) as well as arteries free of atherosclerotic plaques from 13 individuals (45-78 years, controls)., Results: Plasma 25-HC was higher in PAD individuals than in controls (6.3[2] vs. 3.9[1.9] ng/mgCol; p = 0.004). 24S-HC and 27-HC levels were, respectively, five- and 20-fold higher in the arterial tissue of PAD individuals than in those of the controls (p = 0.016 and p = 0.001). Plasma C-reactive protein correlated with plasma 24-HC (r = 0.51; p = 0.010), 25-HC (r = 0.75; p < 0.001), 27-HC (r = 0.48; p = 0.015), and with tissue 24S-HC (r = 0.4; p = 0.041) and 27-HC (r = 0.46; p = 0.023)., Conclusion: Arterial intima accumulation of 27-HC and 24S-HC is associated with advanced atherosclerotic disease and systemic inflammatory activity in individuals with severe PAD.

Background: Misclassification of patients as low cardiovascular risk (LCR) remains a major concern and challenges the efficacy of traditional risk markers. Due to its strong association with cholesterol acceptor capacity, high-density lipoprotein (HDL) size has been appointed as a potential risk marker. Hence, we investigate whether HDL size improves the predictive value of HDL-cholesterol in the identification of carotid atherosclerotic burden in individuals stratified to be at LCR., Methods and Findings: 284 individuals (40-75 years) classified as LCR by the current US guidelines were selected in a three-step procedure from primary care centers of the cities of Campinas and Americana, SP, Brazil. Apolipoprotein B-containing lipoproteins were precipitated by polyethylene glycol and HDL size was measured by dynamic light scattering (DLS) technique. Participants were classified in tertiles of HDL size (<7.57; 7.57-8.22; >8.22 nm). Carotid intima-media thickness (cIMT) <0.90 mm (80th percentile) was determined by high resolution ultrasonography and multivariate ordinal regression models were used to assess the association between cIMT across HDL size and levels of lipid parameters. HDL-cholesterol was not associated with cIMT. In contrast, HDL size >8.22 nm was independently associated with low cIMT in either unadjusted and adjusted models for age, gender and Homeostasis Model Assessment 2 index for insulin sensitivity, ethnicity and body mass index (Odds ratio 0.23; 95% confidence interval 0.07-0.74, p = 0.013)., Conclusion: The mean HDL size estimated with DLS constitutes a better predictor for subclinical carotid atherosclerosis than the conventional measurements of plasma HDL-cholesterol in individuals classified as LCR.

Background: HDL is considered the most important mechanism for the excretion of intracellular cholesterol. The liver is the only organ capable to metabolize cholesterol into bile acid. The enzymatic conversion of cholesterol to bile acid is dependent on the cytochrome P450 microsomal system which is also responsible for the generation of oxysterols. The latter's plasma concentrations may reflect the metabolic processes of specific tissues where they are generated. The objective of this study was to investigate in healthy individuals who differ according to their HDL levels the concentration of oxysterols and relate it to the HDL-dependent cell cholesterol efflux rate., Methods: 24-Hydroxycholesterol, 25-hydroxycholesterol, 27-hydroxycholesterol were determined in plasma by GLC/mass spectrometry in 107 healthy subjects with low HDL (HDL-C<1.03mmol/l) and high HDL cholesterol (HDL-C>1.55mmol/l). HDL-dependent in vitro cell cholesterol efflux rate was measured in 29 cases., Results: No differences were found in plasma oxysterol concentrations between the Low HDL and High HDL groups. There was a significant negative correlation between HDL-C and 27-hydroxycholesterol. Plasma oxysterol concentrations were significantly lower in female than in male subjects. The Low HDL male group had higher 27-hydroxycholesterol than the High HDL male group. Cell cholesterol efflux rate was lower in Low HDL than in High HDL and related inversely with 27-hydroxycholesterol., Conclusion: As compared to High HDL, Low HDL men have increased 27-hydroxycholesterol plasma level that may circumvent their reduced cell cholesterol efflux rate., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Regardless of its effect on the concentrations of serum cholesterol, statins exert pleiotropic effects, including the regulation of endothelial function, reduced oxidative stress and inflammation, as well as a slight improvement in the concentrations of high density lipoprotein (HDL). However, its role on the composition of HDL is not yet established. The aim of this study was to evaluate the composition of HDL subfractions, HDLsub>2 and HDL3, after 14 days of placebo and atorvastatin (10 mg/day) use in 30 asymptomatic volunteers. The serum parameters and the HDL subfractions compositions were determined using radiometric, nephelometric and biochemical enzymatic methods. We observed significant reductions of total cholesterol, low density lipoprotein (LDL) and apolipoprotein B-100 by 28%, 40% and 38%, respectively. The analyses of chemical composition of the subfractions revealed a lower lipid protein ratio in HDL2, suggesting enrichment in proteins, and also lower in HDL3, probably by an increase in the number of particles. Several mechanisms can be suggested for the effects observed after the use of atorvastatin, such as a possible action on the reverse cholesterol transport (decreased activity of hepatic lipase and increased phospholipid transfer protein, PLTP), which would explain the enrichment of HDL. The results suggest that statin use may be relevant in the primary prevention of atherosclerosis not only by its lowering effect on LDLcholesterol and its anti-inflammatory effect but also by beneficial changes in HDL subfractions.

Background: We have searched if plasma high density lipoprotein-cholesterol (HDL-C) concentration interferes simultaneously with whole-body cholesterol metabolism and insulin sensitivity in normal weight healthy adult subjects., Methods: We have measured the activities of several plasma components that are critically influenced by insulin and that control lipoprotein metabolism in subjects with low and high HDL-C concentrations. These parameters included cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), lecithin cholesterol acyl transferase (LCAT), post-heparin lipoprotein lipase (LPL), hepatic lipase (HL), pre-beta-₁HDL, and plasma sterol markers of cholesterol synthesis and intestinal absorption., Results: In the high-HDL-C group, we found lower plasma concentrations of triglycerides, alanine aminotransferase, insulin, HOMA-IR index, activities of LCAT and HL compared with the low HDL-C group; additionally, we found higher activity of LPL and pre-beta-₁HDL concentration in the high-HDL-C group. There were no differences in the plasma CETP and PLTP activities., Conclusions: These findings indicate that in healthy hyperalphalipoproteinemia subjects, several parameters that control the metabolism of plasma cholesterol and lipoproteins are related to a higher degree of insulin sensitivity.

Assessment of lipid profile parameters has been considered a cornerstone in classifying individuals and populations at risk for cardiovascular disease. Recently, however, preliminary data have raised the possibility of seasonal variations in these parameters, which may cause under- or overestimation. Biological rhythms and seasonal variation of lipid profile was investigated in 227 359 consecutive individuals who underwent health checkups in primary care centers between 2008 and 2010. Plasma low-density lipoprotein cholesterol (LDL-C) >130 mg/dL was 8% more prevalent during winter than summer, with a larger difference among women and middle-aged adults (p < 0.001). High-density lipoprotein cholesterol (HDL-C) <40 mg/dL and triglycerides (TG) >150 mg/dL were respectively 9% and 5% more prevalent during the summer (p < 0.001). Variation amplitude was 3.4 ± 0.3 mg/dL for HDL-C (p = 0.005), 7 ± 2 mg/dL for LDL-C (p = 0.047), and 12 ± 9 mg/dL for TG (p = 0.058). Based on a large population sample, this study confirms the existence of biological rhythms and seasonal variation in lipid profile. This finding must be particularly accounted for in cross-sectional analyses of relative risk, prevalence, or the rate of goal achievement for lipid parameters.

Unlabelled: Sterol 27-hydroxylase converts cholesterol to 27-hydroxycholesterol (27-OHC) which is widely distributed among tissues and is expressed at high levels in the vascular endothelium and macrophages. There is a continuous flow of this oxysterol from the tissues into the liver, where it is converted to bile acids., Objective: Measure plasma concentrations of 27-OHC in subjects that differ according to their plasma HDL-C concentration., Methods: Healthy men presenting low HDL-C (<1.03 mmol/L), n=18 or high HDL-C (>1.55 mmol/L), n=18, BMI<30 kg/m² were recruited after excluding secondary causes that might interfere with their plasma lipid concentrations such as smoking, heavy drinking and diabetes. Blood samples were drawn after a 12h fasting period for the measurement of 27-OHC by the combined GC/MS analysis utilizing deuterium-label internal standards., Results: The plasma ratio 27-OHC/total cholesterol (median and range nmoL/mmoL) was 50.41 (27.47-116.00) in the High HDL-C subjects and 63.34 (36.46-91.18) in the Low HDL-C subjects (p=0.0258)., Conclusion: Our data indicate that the production of 27-OHC by extrahepatic tissues and its transport to the liver may represent an alternative pathway for a deficient reverse cholesterol transport system when plasma HDL-C is low., (© 2013.)

Background: Endothelial nitric oxide synthase (eNOS) activity may be modulated by high-density lipoprotein cholesterol (HDL-C), statins or polymorphisms, such as the T-786C of eNOS., Objective: This study aimed at evaluating if the T-786C polymorphism is associated with changes of atorvastatin effects on the lipid profile, on the concentrations of metabolites of nitric oxide (NO) and of high sensitivity C-reactive protein (hsCRP)., Methods: Thirty male volunteers, asymptomatic, aged between 18 and 56 years were genotyped and classified according to absence (TT, n = 15) or presence (CC, n = 15) of the polymorphism. They were randomly selected for the use of placebo or atorvastatin (10 mg/day/14 days). After each treatment lipids, lipoproteins, HDL2 and HDL3 composition, cholesteryl ester transfer protein (CETP) activity, metabolites of NO and hsCRP were evaluated., Results: The comparisons between genotypes after placebo showed an increase in CETP activity in a polymorphism-dependent way (TT, 12±7; CC, 22±12; p < 0.05). The interaction analyses between treatments indicated that atorvastatin has an effect on cholesterol, LDL, nitrite and lipid-protein ratios (HDL2 and HDL3) (p < 0.001) in both genotypes. Interestingly, we observed genotype/drug interactions on CETP (p < 0.07) and lipoprotein (a) (Lp(a)) (p < 0.056), leading to a borderline decrease in CETP, but with no effect on Lp(a). HsCRP showed no alteration., Conclusion: These results suggest that statin treatment may be relevant for primary prevention of atherosclerosis in patients with the T-786C polymorphism of eNOS, considering the effects on lipid metabolism.

The scope of this paper was to evaluate the provision of building maintenance services in health units, by means of a descriptive, quantitative and cross-sectional study, considering the five types of facilities (Primary Health, Emergency, Specialty, Hospital and Mental Health Units). The research was approved by the Research Ethics Comittee of FHEMIG with the Terms of Agreement signed with the Unified Health System of Betim. Comparative analysis was conducted by checking the requirements of "Physical-Functional Structure Management" of the "Brazilian Hospital Accreditation Manual" of the National Accreditation Organization. Nonconformities were noted in the physical-functional management of the health centers, especially the primary health units. The assessment was important, considering that compliance with formal, technical and structural requirements, welfare activities, according to the service organization and appropriate to the profile and complexity, can collaborate to minimize the risks of users. To improve the quality of health care establishments, it is essential that managers, backed by "top management," prioritize financial, human and material resources in planning to ensure compliance with security requirements of users in buildings.

Background: Metabolic predictors and the atherogenicity of oxidized LDL (oxLDL) and the specific antibodies against oxLDL (oxLDL Ab) are unclear and controversial., Methods: In 107 adults without atherosclerotic manifestations, we measured oxLDL and oxLDL Ab, and also the activities of CETP, PLTP, lipases and the carotid intima-media thickness (cIMT). Comparisons were performed for the studied parameters between the lowest and the highest tertile of oxLDL and oxLDL Ab, and the relationships between studied variables were evaluated., Results: Subjects with higher oxLDL Ab present reduced hepatic lipase activity and borderline increased cIMT. In the highest oxLDL tertile, besides the higher levels of total cholesterol, LDL-C and apoB100, we found reduced CETP activity and higher cIMT. A significant correlation between oxLDL Ab and cIMT, independent of oxLDL, and a borderline correlation between oxLDL and cIMT independent of oxLDL Ab were found. In the multivariate analysis, apoAI was a significant predictor of oxLDL Ab, in contrast to regulation of oxLDL by apoB100, PLTP and inverse of CETP., Conclusions: In adults without atherosclerotic disease, the metabolic regulation and carotid atherosclerosis of oxLDL Ab and oxLDL groups, characterized a dual trait in oxLDL Ab, as a contributor to carotid atherosclerosis, much less so than oxidized LDL, and with a modest atheroprotective role., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Cholesteryl ester transfer protein (CETP) plays a major role in lipid metabolism, but studies on the association of CETP polymorphisms with risks of cardiovascular disease are inconsistent. This study investigated whether the CETP gene I405V and Taq1B polymorphisms modified subclinical atherosclerosis in an asymptomatic Brazilian population sample., Methods: The polymorphisms were analyzed using polymerase chain reaction in 207 adult volunteers. Serum lipid profiles, oxLDL Ab titers, C-reactive protein and tumor necrosis factor-α concentrations and CETP and phospholipid transfer protein (PLTP) activities were determined, and common carotid artery intima-media thickness (cIMT) was measured using ultrasonography., Results: No differences in cIMT were observed between the presence or absence of the minor B2 and V alleles in either polymorphism. However, inverse correlations between mean cIMT and CETP activity in the presence of these polymorphisms were observed, and positive correlations of these polymorphisms with PLTP activity and oxLDL Ab titers were identified. Moreover, logistic multivariate analysis revealed that the presence of the B2 allele was associated with a 5.1-fold (CI 95%, OR: 1.26 - 21.06) increased risk for cIMT, which was equal and above the 66th percentile and positively interacted with age. However, no associations with the V allele or CETP and PLTP activities were observed., Conclusions: None of the studied parameters, including CETP activity, explained the different relationships between these polymorphisms and cIMT, suggesting that other non-determined factors were affected by the genotypes and related to carotid atherosclerotic disease.

The plasma cholesterol-reducing effect of phytosterols (PS) has been recognized in several studies, but the usefulness of PS in preventing coronary heart disease remains controversial, as some investigations claim that the high PS concentrations found in plasma and specific tissues are related to an increased risk of cardiovascular events. It has also been demonstrated that PS may induce inflammation and reduce cholesterol efflux from macrophages, conditions that are directly implicated in the development of atherosclerosis. As to arterial dysfunction and atherosclerosis, some studies have concluded that plasma PS concentrations are unrelated or only weakly related or that PS intake or plasma PS concentrations are harmful. Thus, in light of the National Cholesterol Education Program-ATPIII report, it is necessary to evaluate the relevance of their findings. To this end, we have evaluated the studies conducted on cells, animal models, and humans regarding the influence of PS on the development of atherosclerosis., (Copyright © 2012 Wiley Periodicals, Inc.)

We analyzed the effect of a 6-week aerobic exercise training program on the in vivo macrophage reverse cholesterol transport (RCT) in human cholesteryl ester transfer protein (CETP) transgenic (CETP-tg) mice. Male CETP-tg mice were randomly assigned to a sedentary group or a carefully supervised exercise training group (treadmill 15 m/min, 30 min sessions, five sessions per week). The levels of plasma lipids were determined by enzymatic methods, and the lipoprotein profile was determined by fast protein liquid chromatography (FPLC). CETP activity was determined by measuring the transfer rate of ¹⁴C-cholesterol from HDL to apo-B containing lipoproteins, using plasma from CETP-tg mice as a source of CETP. The reverse cholesterol transport was determined in vivo by measuring the [³H]-cholesterol recovery in plasma and feces (24 and 48 h) and in the liver (48 h) following a peritoneal injection of [³H]-cholesterol labeled J774-macrophages into both sedentary and exercise trained mice. The protein levels of liver receptors were determined by immunoblot, and the mRNA levels for liver enzymes were measured using RT-PCR. Exercise training did not significantly affect the levels of plasma lipids or CETP activity. The HDL fraction assessed by FPLC was higher in exercise-trained compared to sedentary mice. In comparison to the sedentary group, a greater recovery of [³H]-cholesterol from the injected macrophages was found in the plasma, liver and feces of exercise-trained animals. The latter occurred even with a reduction in the liver CYP7A1 mRNA level in exercised trained animals. Exercise training increased the liver LDL receptor and ABCA-1 protein levels, although the SR-BI protein content was unchanged. The RCT benefit in CETP-tg mice elicited by exercise training helps to elucidate the role of exercise in the prevention of atherosclerosis in humans.

Background: The antiatherogenic functions of high density lipoprotein (HDL-C) include its role in reverse cholesterol transport, but to what extent the concentration of HDL-C interferes with the whole-body cholesterol metabolism is unknown. Therefore, we measured markers of body cholesterol synthesis (desmosterol and lathosterol) and of intestinal cholesterol absorption (campesterol and β-sitosterol) in healthy subjects that differ according to their plasma HDL-C concentrations., Methods: Healthy participants presented either low HDL-C (< 40 mg/dl, n=33, 17 male and 16 female) or high HDL-C (> 60 mg/dl, n=33, 17 male and 16 female), BMI< 30 kg/m², were paired according to age and gender, without secondary factors that might interfere with their plasma lipid concentrations. Plasma concentrations of non-cholesterol sterols were measured by the combined GC-MS analysis., Results: Plasma desmosterol did not differ between the two groups; however, as compared with the high HDL-C participants, the low HDL-C participants presented higher concentration of lathosterol and lower concentration of the intestinal cholesterol absorption markers campesterol and β-sitosterol., Conclusion: Plasma concentrations of HDL, and not the activities of LCAT and CETP that regulate the reverse cholesterol transport system, correlate with plasma sterol markers of intestinal cholesterol absorption directly, and of cholesterol synthesis reciprocally., (Copyright © 2010 Elsevier B.V. All rights reserved.)

We determined the influence of fasting (FAST) and feeding (FED) on cholesteryl ester (CE) flow between high-density lipoproteins (HDL) and plasma apoB-lipoprotein and triacylglycerol (TG)-rich emulsions (EM) prepared with TG-fatty acids (FAs). TG-FAs of varying chain lengths and degrees of unsaturation were tested in the presence of a plasma fraction at d > 1.21 g/mL as the source of CE transfer protein. The transfer of CE from HDL to FED was greater than to FAST TG-rich acceptor lipoproteins, 18% and 14%, respectively. However, percent CE transfer from HDL to apoB-containing lipoproteins was similar for FED and FAST HDL. The CE transfer from HDL to EM depended on the EM TG-FA chain length. Furthermore, the chain length of the monounsaturated TG-containing EM showed a significant positive correlation of the CE transfer from HDL to EM (r = 0.81, P < 0.0001) and a negative correlation from EM to HDL (r = -041, P = 0.0088). Regarding the degree of EM TG-FAs unsaturation, among EMs containing C18, the CE transfer was lower from HDL to C18:2 compared to C18:1 and C18:3, 17.7%, 20.7%, and 20%, respectively. However, the CE transfer from EMs to HDL was higher to C18:2 than to C18:1 and C18:3, 83.7%, 51.2%, and 46.3%, respectively. Thus, the EM FA composition was found to be the rate-limiting factor regulating the transfer of CE from HDL. Consequently, the net transfer of CE between HDL and TG-rich particles depends on the specific arrangement of the TG acyl chains in the lipoprotein particle core.

Epidemiological studies demonstrate an inverse correlation between plasma HDL-cholesterol (HDL-C) concentration and incidence of cardiovascular disease (CVD). The antiatherogenic role of HDL has been attributed to its anti-inflammatory, antithrombotic and antioxidant properties, besides its participation in the reverse cholesterol transport (RCT), whereby cholesterol from peripheral tissues (including macrophages of the arterial intima) is delivered to the liver for excretion in bile. Due to these actions, HDL-C has evolved as an attractive target for prevention of CVD. However, the failure of torcetrapib, drug that substantially increases HDL-C levels, in preventing CVD and data from studies with animal models and with carriers of monogenic disorders affecting HDL-C levels in humans provide conflicting data about HDL being antiatherogenic. This review addresses the current state of knowledge regarding HDL based on these recent controversies.

We investigated the effects of dietary trans fatty acids, PUFA, and SFA on body and liver fat content, liver histology, and mRNA of enzymes involved in fatty acid metabolism. LDL receptor knockout weaning male mice were fed for 16 wk with diets containing 40% energy as either trans fatty acids (TRANS), PUFA, or SFA. Afterwards, subcutaneous and epididymal fat were weighed and histological markers of nonalcoholic fatty liver disease (NAFLD) were assessed according to the Histological Scoring System for NAFLD. PPARalpha, PPARgamma, microsomal triglyceride transfer protein (MTP), carnitine palmitoyl transferase 1 (CPT-1), and sterol regulatory element binding protein-1c (SREBP-1c) mRNA were measured by quantitative RT-PCR. Food intake was similar in the 3 groups, although mice fed the TRANS diet gained less weight than those receiving the PUFA diet. Compared with the PUFA- and SFA-fed mice, TRANS-fed mice had greater plasma total cholesterol (TC) and triglyceride (TG) concentrations, less epididymal and subcutaneous fat, larger livers with nonalcoholic steatohepatitis (NASH)-like lesions, and greater liver TC and TG concentrations. Macrosteatosis in TRANS-fed mice was associated with a higher homeostasis model assessment of insulin resistance (HOMA(IR)) index and upregulated mRNA related to hepatic fatty acid synthesis (SREBP-1c and PPARgamma) and to downregulated MTP mRNA. Diet consumption did not alter hepatic mRNA related to fatty acid oxidation (PPARalpha and CPT-1). In conclusion, compared with PUFA- and SFA-fed mice, TRANS-fed mice had less adiposity, impaired glucose tolerance characterized by greater HOMA(IR) index, and NASH-like lesions due to greater hepatic lipogenesis. These results demonstrate the role of trans fatty acid intake on the development of key features of metabolic syndrome.

Lipid transfer proteins (PLTP and CETP) play roles in atherogenesis by modifying the arterial intima cholesterol content via altering the concentration and function of plasma lipoproteins and influencing inflammation. In this regard, endotoxins impair the reverse cholesterol transport (RCT) system in an endotoxemic rodent model, supporting a pro-inflammatory role of HDL reported in chronic diseases where atherosclerosis is premature. High PLTP activity related to atherosclerosis in some clinical studies, but the mechanisms involved could not be ascertained. In experimental animals the relation of elevated plasma PLTP concentration with atherosclerosis was confounded by HDL-C lowering and by unfavorable effects on several inflammatory markers. Coincidently, PLTP also increases in human experimental endotoxemia and in clinical sepsis. Human population investigations seem to favor low CETP as atheroprotective; this is supported by animal models where overexpression of huCETP is atherogenic, most likely due to increased concentration of apoB-lipoprotein-cholesterol. Thus, in spite of CETP facilitating the HDL-C-mediated RCT, the reduction of apoB-LP-cholesterol concentration is the probable antiatherogenic mechanism of CETP inhibition. On the other hand, experimental huCETP expression protects mice from the harmful effects of a bacterial polysaccharide infusion and the mortality rate of severely ill patients correlates with reduction of the plasma CETP concentration. Thus, the roles played by PLTP and CETP on atherosclerosis and acute inflammation seem contradictory. Therefore, the biological roles of PLTP and CETP must be carefully monitored when investigating drugs that inhibit their activity in the prevention of atherosclerosis.

This review provides examples of the fact that different procedures for the measurement of atherosclerosis in mice may lead to interpretation of the extent of atherosclerosis having markedly different biological and clinical significance for humans: 1) aortic cholesterol measurement is highly sensitive for the detection of early and advanced atherosclerosis lesions, but misses the identification of the location and complexity of these lesions that are so critical for humans; 2) the histological analysis of the aortic root lesions in simvastatin-treated and control mice reveals similar lesion morphology in spite of the remarkable simvastatin-induced reduction of the aortic cholesteryl ester content; 3) in histological analyses, chemical fixation and inclusion may extract the tissue fat and also shrink and distort tissue structures. Thus, the method may be less sensitive for the detection of slight differences among the experimental groups, unless a more suitable procedure employing physical fixation with histological sample freezing using optimal cutting temperature and liquid nitrogen is employed. Thus, when measuring experimental atherosclerosis in mice, investigators should be aware of several previously unreported pitfalls regarding the extent, location and complexity of the arterial lesion that may not be suitable for extrapolation to human pathology.

Mice expressing human cholesteryl ester transfer protein (huCETP) are more resistant to Escherichia coli bacterial wall LPS because death rates 5 days after intraperitoneal inoculation of LPS were higher in wild-type than in huCETP+/+ mice, whereas all huCETP+/+ mice remained alive. After LPS inoculation, plasma concentrations of TNF-alpha and IL-6 increased less in huCETP+/+ than in wild-type mice. LPS in vitro elicited lower TNF-alpha production by CETP expressing than by wild-type macrophages. In addition, TNF-alpha production by RAW 264.7 murine macrophages increased on incubation with LPS but decreased in a dose-dependent manner when human CETP was added to the medium. Human CETP in vitro enhanced the LPS binding to plasma high-density lipoprotein/low-density lipoprotein. The liver uptake of intravenous infused 14C-LPS from Salmonella typhimurium was greater in huCETP+/+ than in wild-type mice. Present data indicate for the first time that CETP is an endogenous component involved in the first line of defense against an exacerbated production of proinflammatory mediators.

Background: Dietary salt restriction has been reported to adversely modify the plasma lipoprotein profile in hypertensive and in normotensive subjects. We investigated the effects of the low sodium intake (LSI) on the plasma lipoprotein profile and on inflammation and thrombosis biomarkers during the fasting and postprandial periods., Methods: Non-obese, non-treated hypertensive adults (n=41) were fed strictly controlled diets. An initial week on a control diet (CD, Na=160 mmol/day) was followed by 3 weeks on LSI (Na=60 mmol/day). At admission and on the last day of each period, the 24-h ambulatory blood pressure was monitored and blood was drawn after an overnight fasting period and after a fat-rich test meal., Results: The dietary adherence was confirmed by 24-h urinary sodium excretion. Fasting triglyceride (TG), chylomicron-cholesterol, hsC-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) concentrations, renin activity, aldosterone, insulin, and homeostasis model assessment insulin resistance (HOMA-IR) values were higher, but non-esterified fatty acids (NEFA) were lower on LSI than on CD. For LSI, areas under the curve (AUC) of TG, chylomicron-cholesterol, apoB and the cholesterol/apoB ratio were increased, whereas AUC-NEFA was lowered. LSI did not modify body weight, hematocrit, fasting plasma cholesterol, glucose, adiponectin, leptin, fibrinogen and factor VII (FVII), and AUC of lipoprotein lipase and of lipoprotein remnants., Conclusion: LSI induced alterations in the plasma lipoproteins and in inflammatory markers that are common features of the metabolic syndrome.

Purpose: In this study we analyzed the role played by aerobic exercise training in the plasma lipoprotein profile, prebeta 1-HDL concentration, and in the in vitro HDL3 ability to remove cholesterol from macrophages and inhibit LDL oxidation in type 2 diabetes mellitus (DM) patients and control subjects, in the fasting and postprandial states., Methods: Healthy controls (HTC, N = 11; 1 M/10 F) and subjects with type 2 diabetes mellitus (DMT, N = 11; 3M/8F) were engaged in a 4-month aerobic training program, and compared with a group of sedentary subjects with type 2 diabetes mellitus (DMS, N = 10; 4 M/6 F). All groups were submitted to an oral fat load test to analyze all parameters, both at the beginning of the investigation protocol (basal) and at the end of the study period (final)., Results: Exercising did not modify body weight, BMI, plasma concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides (TG), glucose, insulin, or HOMA-IR, but it reduced the waist circumference. The HDL3 composition did not change, and its ability to remove cell cholesterol was unaltered by aerobic training. In DMT but not in HTC, aerobic training improved 15% the HDL3 protective effect against LDL maximal oxidation rate in the fasting state, and reduced 24% the plasma prebeta 1-HDL concentration in the postprandial state, suggesting an enhanced prebeta 1-HDL conversion into larger, more mature HDL particles. In this regard, regular aerobic exercise enriched HDL2 with TG in the fasting and postprandial states in HTC and in the fasting phase in DMT., Conclusion: Our results show that aerobic exercise training in diabetes mellitus improves the HDL efficiency against LDL oxidation and favors HDL maturation. These findings were independent of changes in insulin resistance and of the rise of plasma HDL cholesterol concentration.

Background: Plasma HDL concentrations and composition, important predictors of coronary heart disease, are modified by fatty acids (FAs) in high-fat diets., Objective: Following the National Cholesterol Education Program Adult Treatment Panel III recommendation that 25%-30% of total calorie intake be in the form of fat, we compared the results of the intake of 30% of energy as fat in diets enriched with trans, polyunsaturated, or saturated FAs. These dietary effects on the composition and ability of HDL(2), HDL(3), and total plasma to efflux cholesterol from mouse peritoneal macrophages that previously were loaded with LDL-acetylated 14C-cholesteryl ester were evaluated by using ultracentrifugally isolated lipoproteins., Design: After a 2-wk run-in period, 30 healthy persons (9 M, 21 F), were randomly distributed among 3 groups (n = 10/group) and fed for 4 wk with either an 8.3% trans FA, a 14.6% polyunsaturated FA, or a 13.2% saturated FA diet. The 3 diets had similar proportions of monounsaturated FAs., Results: The percentage of radioactive cell cholesterol removal did not vary among these diets, possibly because of the small difference in the composition of the HDL fraction elicited by the different diets. However, the percentage was consistently higher for HDL(3) than for HDL(2)., Conclusion: Differences in the cell cholesterol efflux with these diets were not observed, probably because the changes in the HDL composition were quite modest as a result of the limitation of the fat intake to 30% of total calories and because of the rigorous control of the proportions of FAs in the experimental diets used in this investigation.

The aim of this work was to study how CETP expression affects whole body cholesterol homeostasis. Thus, tissue uptake and plasma removal rates of labeled HDL-cholesteryl ester (CE), VLDL secretion rates, and biliary lipid secretion and fecal bile acid content were compared between human CETP transgenic (Tg) and non-transgenic (nTg) mice fed with a standard diet. CETP Tg mice exhibited increased HDL-CE plasma fractional catabolic rate and uptake by the liver, adrenals, adipose tissue and spleen. HDL fractions from both CETP Tg and from nTg mice were removed faster from the plasma of CETP expressing than from nTg mice, suggesting a direct role of CETP in accelerating tissue CE uptake. However, neither hepatic output of VLDL cholesterol and triglycerides nor biliary lipid and fecal bile acid excretion were changed in CETP Tg compared to nTg mice. CETP Tg mice also showed enhanced hepatic cholesterol content. Steady state cholesterol homeostasis was probably preserved through the downregulation of hepatic HMG-CoA reductase and LDL receptor expression. In conclusion, although CETP expression facilitates cholesteryl ester tissue uptake, it does not alter biliary lipid and fecal bile acid excretion, the mandatory final step of the reverse cholesterol transport.

1. The hepatic mechanisms involved in the simultaneous regulation of plasma cholesterol concentration and cholesteryl ester transfer protein (CETP) activity were investigated by sharply modifying the hepatic rates of cholesterol synthesis. This was accomplished by cholestyramine, lovastatin and cholesterol feeding in human CETP transgenic mice cross-bred with low-density lipoprotein receptor (LDLr)-knockout mice, generating CETP(+/-)/LDLr(+/-) mice, which present a plasma lipoprotein profile resembling that of humans. 2. Analyses of pooled data showed that the plasma CETP activity correlated positively with plasma total cholesterol concentration, hepatic CETP mRNA and the liver microsomal cholesterol content; a negative correlation was found between plasma CETP activity and the liver 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and LDLr mRNA levels. These coordinated events represent an efficient control system that stabilizes the cell cholesterol content. 3. Nonetheless, not all cholesterol metabolism regulatory systems seem to fit into a coherent pattern of responses, suggesting that other unknown cellular mechanisms play roles depending on the type of pharmacological intervention. 4. For example, microsomal cholesterol content was not affected by cholestyramine, but was increased on cholesterol feeding (as predicted), and, surprisingly, on lovastatin treatment. Furthermore, although both plasma cholesterol-lowering drugs increased CYP7A1 mRNA and had no effect on CYP27 mRNA, other metabolic components were differentially modified. Cholestyramine and lovastatin, respectively, did not modify and increased both HMG-CoA and sterol responsive element binding protein 1c mRNA, did not modify and lowered liver X receptor alpha mRNA, lowered and increased ATP binding cassette A1 mRNA and lowered and did not modify scavenger receptor B1 mRNA. 5. That is, different to unabsorbed cholestyramine, lovastatin, as an absorbed plasma cholesterol-lowering drug, may have modified the activity of other unknown genes that play roles in the interaction of CETP with the metabolism of hepatic cholesterol.

Dietary salt restriction is associated with evidence of low insulin sensitivity. The current study was undertaken to investigate whether sympathetic nervous system and l-arginine-nitric oxide pathway activities are linked to insulin resistance in rats under chronic low salt intake. Male Wistar rats were fed a low (LSD) or normal (NSD) salt diet from weaning to adulthood. A euglycemic hyperinsulinemic clamp was performed in 4 sub-groups on each diet: (1) sympathetic nervous system blockade (propranolol and prazosin), (2) vehicle, (3) L-arginine, and (4) D-arginine. Blood pressure, heart rate and metabolic measurements were done before and 45 min after drug infusion and at the end of the clamp. At baseline conditions, body weight, hematocrit, blood glucose, plasma insulin, cholesterol, and triacylglycerols were higher in LSD than in NSD rats. Systolic blood pressure was lower and heart rate was higher in rats on LSD than on NSD. Glucose uptake was lower on LSD compared to NSD. Sympathetic nervous system blockade and L-arginine did, and vehicle and D-arginine did not improve glucose uptake in LSD rats. On NSD there was no effect of any of the infused drugs. A positive correlation between plasma nitrate and nitrite at the end of clamp and glucose uptake was observed in L-arginine--but not in D-arginine-infused LSD rats. These results provide evidence that the sympathetic nervous system and the L-arginine-nitric oxide pathway are involved in the glucose uptake impairment induced by chronic dietary salt restriction.

The possibility that soy protein containing isoflavones influences the development of experimental atherosclerosis has been investigated in ovariectomized mice heterozygous for the human CETP transgene and for the LDL-receptor null allele (LDLr(+/-) CETP(+/-)). After ovariectomy at 8 wk of age they were fed a fat/cholesterol-rich diet for 19 wk and divided into three experimental groups: dietary unmodified soy protein containing isoflavones (mg/g of diet), either at low-dose (Iso Low, 0.272, n = 25), or at high-dose (Iso High, 0.535, n = 28); and the atherogenic diet containing an isoflavone-depleted alcohol-washed soy protein as a control group (n = 28). Aortic root lipid-stained lesion area (mean microm2 x 10(3) +/- SD) did not differ among Iso Low (12.3 +/- 9.9), Iso High (7.4 +/- 6.4), and controls (10.7 +/- 12.8). Autoantibody titers against plasma oxidized LDL did not differ among the experimental groups. Using the control mice as the reference value (100%), in vitro mouse peritoneal macrophage uptake of labeled acetylated LDL-cholesterol was lower in the Iso High (68%) than in the Iso Low (85%) group. The in vitro percent removal by exogenous HDL of labeled unesterified cholesterol from macrophages previously enriched with human [4- 14C]-cholesteryl oleate acetylated LDL was enhanced in the Iso High group (50%). In spite of these in vitro potentially antiatherogenic actions, soy protein containing isoflavones did not modify the average size of lipid-stained area in the aortic root.

Dyslipoproteinemia of the Nagase analbuminemic rat (NAR) is characterized by elevated concentrations of VLDL and LDL attributed to increased rates of liver lipoprotein synthesis. Increased lysophosphatidylcholine (LPC) in NAR HDL has been attributed to high plasma LCAT activity. We show here that, as compared with Sprague-Dawley rats (SDR), NAR plasma triacylglycerol (TAG), total cholesterol (TC), HDL TAG, protein, total phospholipids (PL), LPC, and PS are increased. These alterations rendered the NAR HDL particle more susceptible to the activity of the enzyme hepatic lipoprotein lipase (HL), which otherwise was unaltered in our study. Fractional catabolic rates in blood of the autologous 125I-apoHDL (median and lower quartile values), were, respectively, 0.231 and 1.645 (n = 10) in NAR as compared with 0.140 and 0.109 (n = 10) in SDR (P = 0.012), corresponding to synthesis rates of HDL protein of 89.8 +/- 33.7 mg/d in NAR and 17.4 +/- 6.5 mg/d in SDR (P = 0.0122). Furthermore, Swiss mouse macrophage free-cholesterol (FC) efflux rates, measured as the percent [14C]-cholesterol efflux/6 h, were 8.2 +/- 2.3 (n = 9) in NAR HDL and 11.2 +/- 3.2 (n = 10) in SDR HDL (P = 0.03). Therefore, in NAR the modification of the HDL composition slows down the cell FC efflux rate, and together with the increased rate of plasma HDL metabolism influences the reverse cholesterol transport system.

Objective: The mechanisms whereby advanced glycation end products (AGE) contribute to atherogenesis in diabetes mellitus are not fully understood. In this study we analyzed in vitro the influence of advanced glycated albumin (AGE-albumin) as well as the role of the AGE inhibitors--aminoguanidine (AMG) and metformin (MF)--on the cell cholesterol efflux., Methods: HDL3 and albumin-mediated cholesterol efflux was measured in mouse peritoneal macrophages and in SR-BI transfected cells that had been treated along time with dicarbonyl sugars or AGE-albumin, both in the presence or in the absence of AMG and MF. 125I-HDL3 cell binding and 125I-AGE-albumin cell degradation were measured. Carboxymethyllysine (CML) formation and SR-BI expressions were determined by immunoblot., Results: AGE-albumin efficiently trapped cell cholesterol but impaired the HDL-mediated cell cholesterol efflux by decreasing HDL binding to the cell surface and inducing intracellular glycoxidation, without interfering with the SR-BI expression. Cell treatment with dicarbonyl sugars also disrupted the HDL-mediated cell cholesterol efflux, but this was prevented by AMG and MF that reduced CML formation., Conclusions: By adversely impairing the HDL-mediated cell cholesterol removal rate, AGE-albumin and cell glycoxidation could facilitate the development of premature atherosclerosis in diabetes mellitus (DM) and in other diseases associated with carbonyl and oxidative stress like in chronic uremia. Thus, drugs that prevent AGE formation may be useful to correct disturbances in cell cholesterol transport.

Modifications in chylomicron metabolism caused by antihypertensive drugs were investigated in hypertensive subjects because previous studies had indicated that diuretics and beta-blockers modify the plasma lipid concentrations through mechanisms that were not fully understood. A triglyceride-rich emulsion resembling lymph chylomicrons, labeled with (3H) triolein and (14C) cholesteryl oleate, was infused intravenously into mildly hypertensive patients after 8 weeks on placebo and subsequently on hydrochlorothiazide (n = 10) or propranolol (n = 8). The residence time of both radioactivities in plasma was utilized for the simultaneous calculation of the particle remnant removal rate and of the lipoprotein lipase activity expressed as a delipidation index = 1 - [(3H) triolein residence time/(14C) cholesteryl oleate residence time]. Treatment with hydrochlorothiazide diminished the delipidation rate value whereas propranolol mildly increased the removal rate of the remnant particle. These alterations of the chylomicron kinetics were not accompanied by changes in plasma triglycerides, glucose, and insulin concentration as measured in the fasting state. The impairment of the lipoprotein lipase activity by thiazides and the faster removal rate of the whole particle by propranolol could explain the reason why in previous clinical studies the simultaneous use of these drugs does not aggravate the hyperlipidemia known to be induced by thiazides alone.

Several studies support the hypothesis that chronic diseases in adulthood might be triggered by events that occur during fetal development. This study examined the consequences of perinatal salt intake on blood pressure (BP) and carbohydrate and lipid metabolism in adult offspring of dams on high-salt [HSD; 8% (HSD2) or 4% (HSD1)], normal-salt (NSD; 1.3%), or low-salt (LSD; 0.15% NaCl) diet during pregnancy and lactation. At 12 wk of age, female Wistar rats were matched with adult male rats that were fed NSD. Weekly tail-cuff BP measurements were performed before, during, and after pregnancy. After weaning, the offspring received only NSD and were housed in metabolic cages for 24-h urine collection for sodium and potassium and nitrate and nitrite excretion measurements. At 12 wk of age, intra-arterial mean BP was measured, a euglycemic-hyperinsulinemic clamp was performed, and plasma lipids and nitrate and nitrite concentrations were determined. Tail-cuff BP was higher during pregnancy in HSD2 and HSD1 than in NSD and LSD dams. Mean BP (mm Hg) was also higher in the offspring of HSD2 (110 +/- 5) and HSD1 (107 +/- 5) compared with NSD (100 +/- 2) and LSD (92 +/- 2). Lower glucose uptake and higher plasma cholesterol and triacylglycerols were observed in male offspring from LSD dams (glucose uptake: HSD2 17 +/- 4, HSD1 15 +/- 3, NSD 11 +/- 3, LSD 4 +/- 1 mg . kg(-1) . min(-1); cholesterol: HSD2 62 +/- 6, HSD1 82 +/- 11, NSD 68 +/- 10, LSD 98 +/- 17 mg/dL; triacylglycerols: HSD2 47 +/- 15, HSD1 49 +/- 12, NSD 56 +/- 19, LSD 83 +/- 11 mg/dL). In conclusion, maternal salt intake during pregnancy and lactation has long-term influences on arterial pressure, insulin sensitivity, and plasma lipids of the adult offspring.

Smoking is a leading cause of atherosclerosis acting trough a wide spectrum of mechanisms, notably the increase of the proatherogenic effect of dyslipidemia. However, a severe atherosclerotic disease is frequently observed in smokers who do not present an overt dyslipidemia. In the present study, we sought to determine if abnormalities in lipid metabolism occur in normolipidemic smokers, focusing especially on the components of intravascular remodeling of high-density lipoprotein (HDL) For this purpose, we measured lipid transfer proteins and enzymes involved in the reverse cholesterol transport (RCT) system in 29 adults: 15 smokers and 14 controls. The blood samples were drawn in the fasting state, immediately after the smokers smoked 1 cigarette. The composition of HDL particles was analyzed after isolation of HDL fractions by microultracentrifugation. We observed that normolipidemic smokers present higher total plasma and HDL phospholipids (PL) (P < .05), 30% lower postheparin hepatic lipase (HL) activity (P < .01), and 40% lower phospholipid transfer protein (PLTP) activity (P < .01), as compared with nonsmokers. The plasma cholesteryl ester transfer protein (CETP) mass was 17% higher in smokers as compared with controls (P < .05), but the endogenous CETP activity corrected for plasma triglycerides (TG) was in fact 57% lower in smokers than in controls (P < .01). Lipid transfer inhibitor protein activity was also similar in both groups. In conclusion, the habit of smoking induces a severe impairment of many steps of the RCT system even in the absence of overt dyslipidemia. Such an adverse effect might favor the atherogenicity of smoking.

We investigated 95 Brazilian adults, aged 21-79 years, who were divided into two groups defined as having high-density lipoprotein (HDL)-cholesterol concentrations above [hyperalphalipoproteinaemia (HALP); n=48] or below (controls; n=47) the 90th percentile of a local population. The activities of lipid transfer proteins and enzymes involved in the plasma reverse cholesterol transport and the prevalence of factors that modulate HDL metabolism (alcohol consumption, ponderosity, physical exercise, menopause and use of hormone replacement treatment in women and smoking) were measured, as well as the prevalence of cardiovascular disease and of its various risk factors. The two groups showed no differences in their frequencies of cardiovascular disease. The HDL2/HDL3-cholesterol and triacylglycerol (triglyceride) ratios and the activities of the phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein (CETP) were similar in both groups. Lipoprotein lipase (LPL) and hepatic lipase (HL) activities were 35% higher (P=0.0002) and 40% lower (P=0.0006) respectively, in HALP compared with control subjects. In a multivariate analysis, HDL-cholesterol and its subfractions were influenced by LPL, apolipoprotein A-I, age (negative relationship) and body mass index (negative relationship). Use of alcohol and ponderosity, as well as the interaction of these factors, explained the LPL activity. HL activity was modulated by smoking, and hormone-replacement therapy influenced the apolipoprotein A-I concentration. CETP activity was influenced by race and PLTP by age. The unique phenotype found in this Brazilian HALP population, namely low HL and high LPL activities, could be determined mostly by genetic components, on which future work will focus.

This study aimed at measuring the influence of a low salt diet on the development of experimental atherosclerosis in moderately hyperlipidemic mice. Experiments were carried out on LDL receptor (LDLR) knockout (KO) mice, or apolipoprotein E (apoE) KO mice on a low sodium chloride diet (LSD) as compared with a normal salt diet (NSD). On LSD, the rise of the plasma concentrations of TG and nonesterified fatty acid (NEFA) was, respectively, 19% and 34% in LDLR KO mice, and 21% and 35% in apoE KO mice, and that of plasma cholesterol was limited to the LDLR KO group alone (15%). Probably due to the apoE KO severe hypercholesterolemia, the arterial inner-wall fat storage was not influenced by the diet salt content and was far more abundant in the apoE KO than in the LDLR KO mice. However, in the less severe hypercholesterolemia of the LDLR KO mice, lipid deposits on the LSD were greater than on the NSD. Arterial fat storage correlated with NEFA concentrations in the LDLR KO mice alone (n = 14, P = 0.0065). Thus, dietary sodium chloride restriction enhances aortic wall lipid storage in moderately hyperlipidemic mice.

Reduced estrogen levels result in loss of protection from coronary heart disease in postmenopausal women. Enhanced and diminished atherosclerosis have been associated with plasma levels of cholesteryl ester transfer protein (CETP); however, little is known about the role of CETP-ovarian hormone interactions in atherogenesis. We assessed the severity of diet-induced atherosclerosis in ovariectomized (OV) CETP transgenic mice crossbred with LDL receptor knockout mice. Compared with OV CETP expressing ((+)), OV CETP non-expressing ((-)) mice had higher plasma levels of total, VLDL-, LDL-, and HDL-cholesterol, as well as higher antibodies titers against oxidized LDL. The mean aortic lesion area was 2-fold larger in OV CETP(-) than in OV CETP(+) mice (147 +/- 90 vs. 73 +/- 42 x 10(3) micro m(2), respectively). Estrogen therapy in OV mice blunted the CETP dependent differences in plasma lipoproteins, oxLDL antibodies, and atherosclerosis severity. Macrophages from OV CETP(+) mice took up less labeled cholesteryl ether (CEt) from acetyl-LDL than macrophages from OV CETP(-) mice. Estrogen replacement induced a further reduction in CEt uptake and an elevation in HDL mediated cholesterol efflux from pre-loaded OV CETP(+) as compared with OV CETP(-) macrophages. These findings support the proposed anti-atherogenic role of CETP in specific metabolic settings.

Chylomicrons play a role in atherosclerosis, however, because the mechanisms involved in the cell uptake of these particles are not fully understood, investigations were carried out using a radioactively labeled protein-free triacylglycerol-rich emulsion incubated with peritoneal macrophages obtained from normal and apoE-knockout mice. Experiments were done in the presence of substances that inhibit several endocytic processes: EDTA for low density lipoprotein receptor, fucoidan for scavenger receptor, cytochalasin B for phagocytosis, and a lipopolysaccharide for lipoprotein lipase. In addition, triacylglycerol-rich emulsions were also prepared in the presence of native or modified radioactively labeled low density lipoprotein particles that are known to accumulate in the arterial intima. Probucol was also used to prevent the possible role played by an antioxidant in triacylglycerol-rich emulsion uptake. We have shown that triacylglycerol-rich emulsion alone is taken up by a coated-pit-dependent mechanism, mediated by macrophage secretion of apolipoprotein E. Furthermore, native, aggregated, acetylated, and moderately macrophage-oxidized low density lipoprotein stimulate the uptake of a triacylglycerol-rich emulsion through several mechanisms such as an actin-dependent pathway, scavenger receptors, and lipolysis mediated by lipoprotein lipase. On the other hand, in spite of the interaction of low density lipoprotein forms with a triacylglycerol-rich emulsion, the cellular triacylglycerol-rich emulsion uptake is impaired by copper-oxidized low density lipoprotein, possibly due to its diminished affinity towards lipoprotein lipase. We have also shown that macrophages take up aggregated low density lipoprotein better than the acetylated or oxidized forms of low density lipoprotein., (Copyright 2001 Wiley-Liss, Inc.)

Studies in humans have indicated that dietary salt restriction raises plasma levels of total cholesterol (TC) and triacylglycerols (TAG). In order to explain the mechanisms involved, a rat experimental model was developed consisting of chronic feeding ad libitum isocaloric diets with variable sodium chloride contents. Rates of synthesis of plasma TAG were measured either as the increase of plasma TAG after blocking its removal from plasma by the intra-arterial pulse infusion of Triton-WR 1339, or as the plasma rate of incorporation of [(14)C]-oleic acid [(14)C]-TAG. Plasma TAG removal rate was determined by the intra-arterial pulse infusion of a lipid emulsion. Severe salt restriction increased the plasma concentrations of TAG (71%) and of TC (10%). This result was not due to modification of the rate of synthesis of plasma TAG but was attributed to a 55% slower rate of removal of the TAG-containing lipoproteins. An increased plasma non-esterified fatty acid concentration, probably due to a salt restriction-related insulin resistance, may have impaired the activity of the enzyme lipoprotein lipase.

The incidence of atherosclerosis is increased in growth hormone (GH) deficient-individuals. Nonetheless, the antiatherogenic benefits of GH replacement therapy remain uncertain. In this study the effect of human recombinant growth hormone (hrGH) replacement therapy administered to GH-deficient adults on the plasma cholesteryl ester transfer protein (CETP) concentration and activity was analyzed. These findings were related to changes in the concentrations of the plasma lipoproteins. The hrGH was administered for 12 mon to human GH-deficient patients (n = 13; 8 men, 5 women). During the study plasma lipoproteins were separated by ultracentrifugation, and plasma cholesterol esterification rate (CER), endogenous CETP activity, and CETP concentration were measured. GH replacement therapy transiently (at 3 mon) lowered plasma concentration of CETP and low density lipoprotein-cholesterol (LDL-C) and raised total triglycerides. Furthermore, hrGH permanently increased both the plasma lipoprotein(a) [Lp(a)] concentration, which is known as atherogenic, and the proportion of cholesteryl ester in the high density lipoprotein2 (HDL2) particles, which is potentially atheroprotective. The simultaneous decrease of the plasma CETP and LDL-C concentrations elicited by hrGH indicated a close relationship between LDL metabolism and the regulation of the CETP gene expression. Endogenous CETP activity and the CER were not modified because these parameters are regulated in opposite ways by plasma levels of triglycerides; that is, CER increased and CETP decreased.

Increased postprandial lipemia has been stated as one of the mechanisms responsible for atherogenesis in smokers. We measured the postalimentary lipid response and the in vivo intravascular delipidation index of an artificial chylomicron emulsion in healthy adult smokers and controls. The blood was collected in the fasting state immediately after the smokers smoked one cigarette. The lipemia was measured 2, 4, 6 and 8 h postalimentarily in smokers (S, n = 8) and in non-smoking controls (C, n = 8) and the chylomicron metabolism rate was measured 2, 4, 6, 8, 12, 16, 20, 24 and 30 min after the injection of an artificial emulsion to S (n = 10) and to C (n = 10). The lipoproteins were isolated in the fasting period and 4 h after the fatty meal and their chemical composition in cholesterol, triglycerides, phospholipids and protein was determined. Smokers showed an increased lipolysis percentage value (mean +/- S.E.M.) of the artificial chylomicron (39.1 +/- 3.1) compared to controls (26.5 +/- 3.3) and higher levels of HDL(2)-PL: 28.4 +/- 4.3 (S) versus 16.2 +/- 2.0 (C) mg/dl (mean +/- S.E.M.). In conclusion, the oral fat tolerance was not altered in smokers but an upregulation of the rate of metabolism of the TG-rich lipoproteins was elicited immediately after smoking one cigarette.

Cholesteryl ester transfer protein (CETP) plays a controversial role in atherogenesis by contributing to the net transfer of high density lipoprotein (HDL) cholesteryl ester (CE) to the liver via apolipoprotein-B-containing lipoproteins (apoB-LP). We evaluated in vitro the CETP-mediated bidirectional transfer of CE from HDL to the chemically modified pro-atherogenic low density lipoprotein (LDL) particles. Acetylated or oxidized (ox) LDL, either unlabeled or [3H]-CE labeled, were incubated with [14C]-CE-HDL in the presence of the lipoprotein-deficient plasma fraction (d>1.21 g/ml) as the source of CETP. The amount of radioactive CE transferred was determined after dextran sulfate/MgCl(2) precipitation of LDL. The results showed a 1.4-2.8-fold lower HDL-CE transfer to acetylated LDL while no effect was observed on the CE transfer to oxidized LDL. However, the reverse transfer rate of [3H]CE-LDL to HDL was 1.4-3.6 times greater when LDL was oxidized than when it was intact. Overall, HDL(2) was better than HDL(3) as donor of CE to native LDL, probably reflecting the relatively greater CE content of HDL(2). Oxidation of LDL enhanced the CETP-mediated cholesteryl ester transfer rate to HDL, bringing on a reduced net transfer rate of cholesteryl ester from HDL to ox LDL. This may diminish the oxLDL particle's atherogenic effect.

Background: Plasma lipases and lipid transfer proteins are involved in the generation and speciation of high density lipoproteins. In this study we have examined the influence of plasma lipases and lipid transfer protein activities on the transfer of free cholesterol (FC) and phospholipids (PL) from lipid emulsion to human, rat and mouse lipoproteins. The effect of the lipases was verified by incubation of labeled (3H-FC,14C-PL) triglyceride rich emulsion with human plasma (control, post-heparin and post-heparin plus lipase inhibitor), rat plasma (control and post-heparin) and by the injection of the labeled lipid emulsion into control and heparinized functionally hepatectomized rats., Results: In vitro, the lipase enriched plasma stimulated significantly the transfer of 14C-PL from emulsion to high density lipoprotein (p<0.001) but did not modify the transfer of 3H-FC. In hepatectomized rats, heparin stimulation of intravascular lipolysis increased the plasma removal of 14C-PL and the amount of 14C-PL found in the low density lipoprotein density fraction but not in the high density lipoprotein density fraction. The in vitro and in vivo experiments showed that free cholesterol and phospholipids were transferred from lipid emulsion to plasma lipoproteins independently from each other. The incubation of human plasma, control and control plus monoclonal antibody anti-cholesteryl ester transfer protein (CETP), with 14C-PL emulsion showed that CETP increases 14C-PL transfer to human HDL, since its partial inhibition by the anti-CETP antibody reduced significantly the 14C-PL transfer (p<0.05). However, comparing the nontransgenic (no CETP activity) with the CETP transgenic mouse plasma, no effect of CETP on the 14C-PL distribution in mice lipoproteins was observed., Conclusions: It is concluded that: 1-intravascular lipases stimulate phospholipid transfer protein mediated phospholipid transfer, but not free cholesterol, from triglyceride rich particles to human high density lipoproteins and rat low density lipoproteins and high density lipoproteins; 2-free cholesterol and phospholipids are transferred from triglyceride rich particles to plasma lipoproteins by distinct mechanisms, and 3 - CETP also contributes to phospholipid transfer activity in human plasma but not in transgenic mice plasma, a species which has high levels of the specific phospholipid transfer protein activity.