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Background: Small non-coding microRNAs (miR) have important regulatory roles and are used as biomarkers of disease. We investigated the relationship between lipoproteins and circulating miR-30c, evaluated how they are transported in circulation and determined whether statins altered the circulating concentration of miR-30c., Methods: To determine the relationship between lipoproteins and circulating miR-30c, serum samples from 79 subjects recruited from a lipid clinic were evaluated. Ultracentrifugation and nanoparticle tracking analysis was used to evaluate the transportation of miR-30c in the circulation by lipoproteins and extracellular vesicles in three healthy volunteers. Using archived samples from previous studies, the effects of 40mg rosuvastatin (n=22) and 40mg pravastatin (n=24) on miR-30c expression was also examined. RNA extraction, reverse transcription-quantitative real-time polymerase chain reaction was carried out using standard procedures., Results: When stratified according to total cholesterol concentration, there was increased miR-30c expression in the highest compared to the lowest tertile (p=0.035). There was significant positive correlation between miR-30c and total- (r=0.367; p=0.002) and LDL-cholesterol (r=0.391; p=0.001). We found that miR-30c was transported in both exosomes and on HDL3. There was a 3.8-fold increased expression of circulating miR-30c after pravastatin treatment for 1year (p=0.005) but no significant change with atorvastatin after 8weeks (p=0.145)., Conclusions: This study shows for the first-time in humans that circulating miR-30c is significantly, positively correlated with total- and LDL-cholesterol implicating regulatory functions in lipid homeostasis. We show miR-30c is transported in both exosomes and on HDL3 and pravastatin therapy significantly increased circulating miR-30c expression adding to the pleiotropic dimensions of statins., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Circulating miR-30c has been linked to various aspects of cholesterol homeostasis. The aim of this study was to determine the association of circulating miR-30c with the atherogenic lipoprotein subfractions. Samples from subjects who were given placebo (n=22) in a randomised, double-blind crossover study were used. Subjects were divided into non-atherogenic lipoprotein phenotype (Non-ALP; n=12; triglycerides <2.0mmol/L) and atherogenic lipoprotein phenotype (ALP; n=10; triglycerides ≥2.0mmol/L) groups. All lipid and lipoprotein measurements, RNA extraction and reverse transcription-quantitative real-time polymerase chain reaction were undertaken using standard procedures. Subjects with ALP weighed significantly more than their non-ALP counterparts (p=0.023). In the non-ALP group there was significant correlation between miR-30c and components within VLDL1, namely triglyceride which showed a negative association (p=0.035) whereas phospholipids and cholesterol-ester were both positively correlated (p=0.025 and 0.014, respectively). In contrast, in the ALP group there was a significant correlation between the expression of miR-30c and components within VLDL2, namely triglyceride, which was positively associated (p=0.013). This study reveals specificity with regards to the effect of miR-30c on VLDL subfractions based on the individual's lipoprotein phenotype and implicates roles for microsomal-triglyceride transfer-protein and cholesteryl-ester-transfer-protein in LDL and VLDL metabolism, respectively., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Although many randomized controlled trials (RCTs) have examined the effects of the n-3 (ω-3) fatty acids eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) on blood pressure (BP) and vascular function, the majority have used doses of EPA+DHA of >3 g/d, which are unlikely to be achieved by dietary manipulation., Objective: The objective was to examine, by using a retrospective analysis from a multicenter RCT, the impact of recommended EPA+DHA intakes achievable through diet on systolic and diastolic BPs and microvascular function in adults in the United Kingdom., Methods: In a double-blind, placebo-controlled RCT, healthy men and women (n = 312) consumed a control oil or fish oil (FO) providing 0.7 or 1.8 g EPA+DHA/d, in random order, each for 8 wk. Fasting BP and microvascular function (using laser Doppler iontophoresis) were assessed and plasma collected for the quantification of markers of vascular function. Participants were retrospectively genotyped for the endothelial nitric oxide synthase (eNOS) rs1799983 variant., Results: No effects of n-3 fatty acid treatment or any treatment × eNOS genotype interactions were evident in the group as a whole for any of the clinical or biochemical outcomes. Assessment of response according to hypertension status at baseline indicated a significant (P = 0.046) FO-induced reduction (mean: 5 mm Hg) in systolic BP, specifically in those with isolated systolic hypertension (n = 31). No dose response was observed., Conclusions: These findings indicate that in adults with isolated systolic hypertension, daily doses of EPA+DHA as low as 0.7 g show clinically meaningful BP reductions, which, at a population level, could be associated with lower cardiovascular disease risk. Confirmation of findings in an RCT in which participants are prospectively recruited on the basis of BP status is required to draw definite conclusions., (© 2016 American Society for Nutrition.)

Objective: Amniotic membrane (AM) is used to manage various debilitated ocular surface conditions. The impact of oxidative stress and free radicals on the ocular surface is increasingly being recognized. Hyaluronic acid (HA) has anti-inflammatory properties and is abundantly present in AM. In this in vitro pilot study, we investigated the potential of AM for intrinsic free radical scavenging properties., Methods: Strips of AM were incubated in sealed tubes with hydrogen peroxide (H2O2). After being sonicated, uptake of reactive oxygen species (ROS) was measured by the Amplex Red Hydrogen Peroxide/Peroxidase assay. For comparison, 1630 kDA HA was used., Results: There was uptake of ROS by all AM samples, which decreased with increasing concentrations of H2O2. Mean ROS uptake for 5 different AMs at 1 hour was significantly greater for 50 μM (83%; SD 11.7, SEM 5.23) compared with 100 μM (67%; SD 20.48, SEM 9.16; p = 0.028; 95% CI 2.8-29.2). The HA comparison group showed similar uptake and trend., Conclusion: This pilot study demonstrates that AM is able to remove ROS from its environment. Demonstrating total antioxidant capacity in AM provides evidence for use as a free radical scavenger. The antioxidant properties of AM and the contribution from HA require more research., (Copyright © 2014 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.)

Scavenger receptor class B type I (SR-BI) and cluster determinant 36 (CD36) have been involved in cellular uptake of some provitamin A carotenoids. However, data are incomplete (e.g., there are no data on α-carotene), and it is not known whether genetic variants in their encoding genes can affect provitamin A carotenoid status. The objectives were 1) to assess the involvement of these scavenger receptors in cellular uptake of the main provitamin A carotenoids (i.e., β-carotene, α-carotene, and β-cryptoxanthin) as well as that of preformed vitamin A (i.e., retinol) and 2) to investigate the contribution of genetic variations in genes encoding these proteins to interindividual variations in plasma concentrations of provitamin A carotenoids. The involvement of SR-BI and CD36 in carotenoids and retinol cellular uptake was investigated in Caco-2 and human embryonic kidney (HEK) cell lines. The involvement of scavenger receptor class B type I (SCARB1) and CD36 genetic variants on plasma concentrations of provitamin A carotenoids was assessed by association studies in 3 independent populations. Cell experiments suggested the involvement of both proteins in cellular uptake of provitamin A carotenoids but not in that of retinol. Association studies showed that several plasma provitamin A carotenoid concentrations were significantly different (P < 0.0083) between participants who bore different genotypes at single nucleotide polymorphisms and haplotypes in CD36 and SCARB1. In conclusion, SR-BI and CD36 are involved in cellular uptake of provitamin A carotenoids, and genetic variations in their encoding genes may modulate plasma concentrations of provitamin A carotenoids at a population level.

Here the impact of APOE genotype on CHD risk in UK adults is reported, along with an analysis of APOE genotype × BMI/age/sex interactions. APOE genotype had a significant impact on fasting total:LDL-cholesterol (TC:LDL-C) ratio, triglycerides, % HDL3, and the Framingham 10-year CVD risk score (P<0.05), with an overall trend towards lower and higher risk in E2- and E4-carriers, respectively, relative to the wild-type E3/E3 genotype. A greater impact of genotype on TC:HDL-C was observed in females, which explained 16% of the variability in this outcome versus 6% in males. APOE genotype was also associated with plasma C-reactive protein and adhesion molecule concentrations (P<0.05), with significant genotype × BMI interactions observed. Our observations indicate that the association between the APOE genotype and CHD risk is unlikely to be homogenous and highlights the risk of inaccurate estimations of genotype-phenotype associations in population subgroups without appropriate stratification for sex and adiposity., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Objective: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an inflammatory biomarker that circulates mainly bound to LDL. We evaluated the association of Lp-PLA(2) with vascular events in the elderly where the importance of LDL is diminished as a risk factor for coronary disease., Methods: Mass and activity of Lp-PLA(2) were related to risk over 3.2 years for vascular events (definite or suspected death from CHD, non-fatal MI, fatal or non-fatal stroke) in the 2804 men and 3000 women age 70-82 years in the Prospective Study of Pravastatin in the Elderly (PROSPER)., Results: Lp-PLA(2) showed a moderate, positive association with risk of a vascular event with hazard ratios of 1.25 (confidence interval (CI) 1.02-1.54) for mass and 1.39 (CI 1.14-1.70) for activity for top versus bottom quartile. Risk associations were attenuated when classical risk factors, lipids and inflammatory markers - C-reactive protein and white cell count - were included in the models. Lp-PLA(2) was unrelated to stroke risk. Inclusion of all three inflammatory markers in multivariate models negated the association of HDL cholesterol with risk (hazard ratio 0.98; CI 0.88-1.10) and increased prediction of coronary events; the C statistic rose from 63.2% to 64.4% (P<0.001)., Conclusion: In elderly people Lp-PLA(2), alongside other inflammatory indices, is a potential biomarker for vascular events, particularly CHD., (Copyright 2009 Elsevier Ireland Ltd. All rights reserved.)

Objectives: To investigate the impact of apolipoprotein E (apoE) genotype on the response of the plasma lipoprotein profile to eicosapentaenoic acid (EPA) versus docosahexaenoic acid (DHA) intervention in humans., Methods and Results: 38 healthy normolipidaemic males, prospectively recruited on the basis of apoE genotype (n=20 E3/E3 and n=18 E3/E4), completed a double-blind placebo-controlled cross-over trial, consisting of 3 x 4 week intervention arms of either control oil, EPA-rich oil (ERO, 3.3g EPA/day) or DHA-rich oil (DRO, 3.7g DHA/day) in random order, separated by 10 week wash-out periods. A significant genotype-independent 28% and 19% reduction in plasma triglycerides in response to ERO and DRO was observed. For total cholesterol (TC), no significant treatment effects were evident; however a significant genotype by treatment interaction emerged (P=0.045), with a differential response to ERO and DRO in E4 carriers. Although the genotype x treatment interaction for LDL-cholesterol (P=0.089) did not reach significance, within DRO treatment analysis indicated a 10% increase in LDL (P=0.029) in E4 carriers with a non-significant 4% reduction in E3/E3 individuals. A genotype-independent increase in LDL mass was observed following DRO intervention (P=0.018). Competitive uptake studies in HepG2 cells using plasma very low density lipoproteins (VLDL) from the human trial, indicated that following DRO treatment, VLDL(2) fractions obtained from E3/E4 individuals resulted in a significant 32% (P=0.002) reduction in LDL uptake relative to the control., Conclusions: High dose DHA supplementation is associated with increases in total cholesterol in E4 carriers, which appears to be due to an increase in LDL-C and may in part negate the cardioprotective action of DHA in this population subgroup.

Background: Patients with nephrotic range proteinuria have a marked increase in the risk of cardiovascular disease. Qualitative and quantitative changes in lipids and lipoproteins contribute to this increased risk with an abundance of atherogenic triglyceride (TG) rich apolipoprotein B containing lipoproteins. TG rich lipoproteins predominate postprandially and are associated with increased risk of coronary heart disease (CHD). Omega-3 fatty acids derived from fish oils have been shown to have beneficial effects on lipids and lipoproteins in patients without proteinuria., Methods: 17 patients with nephrotic range proteinuria and 17 age and sex matched controls were studied. Postprandial lipaemia was assessed in patients and controls, before and after 8 weeks treatment with 4 g daily of omega-3 fatty acids (Omacor). A standard fat load (90 g) was administered and blood sampling was performed in the fasting state and at 2, 4, 6 and 8h after the fat load. Chylomicrons and VLDL(1) density fraction was isolated from plasma by density ultracentrifugation. Postprandial chylomicron and VLDL(1) triglyceride concentrations were measured and quantified using the incremental area under the curve (AUC) method., Results: Baseline postprandial chylomicron TG AUC was greater in patients compared with controls: median 18.5 mmol/lh (interquartile range 8.9-32.6) vs 9.3 mmol/lh (4.8-14.4) p=0.05. Following treatment patient chylomicron AUC fell [mean reduction 6.8 mmol/lh (95% CI 0.1-13.6) p=0.05]. No significant reduction in chylomicron AUC was observed in the controls [mean reduction 3.9 mmol/lh (95% CI -3.6 to 11.5)]. As a result, following 8 weeks treatment with omega-3 fatty acids, patient and control chylomicron AUC were no longer significantly different [patients 13.5 mmol/lh (7.4-22.9), controls 7.2 mmol/lh (4.6-14.5) both median and IQR, p=nsd]. VLDL(1) TG AUC did not differ at baseline between patients and controls. Furthermore, there was no significant effect on VLDL(1) AUC following treatment in either group., Conclusions: We have shown that there is an excess of postprandial chylomicron density fraction in patients with nephrotic range proteinuria, which is reduced by treatment with omega-3 fatty acids. We suggest that this would be an ideal therapy in combination with statins for this high risk group of patients.

Background: Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder associated with low circulating levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B100 (ApoB). A proband was identified in whom the condition was due to an E110X mutation of APOB, creating a particularly early truncation of ApoB in the region of the molecule necessary for very-low-density lipoprotein (VLDL) assembly. The mutation was also associated with nonalcoholic fatty liver disease., Objective: To assess the effect of the mutation on metabolism and the formation of VLDL and LDL subfractions., Results: Both the proband and his son, who had the same mutation, had low LDL cholesterol and decreased ApoB, but an increased small-dense LDL level. Lipoprotein profiles were normal in the proband's sister and grandson, in whom the mutation was absent. In the proband. there was a profoundly diminished rate of production of VLDL-2. VLDL-1 production, however, was relatively preserved and, because of its decreased catabolism, its pool size was increased. Direct formation of intermediate-density lipoprotein (IDL) and LDL was undetectable. Intermediate-density lipoprotein catabolism was greatly increased and its conversion to LDL was increased. The LDL produced was entirely small-dense LDL. High-density lipoprotein cholesterol levels were low, perhaps also related to the relative increase in VLDL-1, which is an avid acceptor of cholesteryl ester., Conclusions: This novel mutation provides evidence to support the hypothesis that hepatic production of large VLDL-1 leads to the creation of small-dense LDL.

Background: The lipid-modulatory effects of high intakes of the fish-oil fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are well established and likely to contribute to cardioprotective benefits., Objectives: We aimed to determine the effect of moderate EPA and DHA intakes (<2 g EPA+DHA/d) on the plasma fatty acid profile, lipid and apolipoprotein concentrations, lipoprotein subclass distribution, and markers of oxidative status. We also aimed to examine the effect of age, sex, and apolipoprotein E (APOE) genotype on the observed responses., Design: Three hundred twelve adults aged 20-70 y, who were prospectively recruited according to age, sex, and APOE genotype, completed a double-blind placebo-controlled crossover study. Participants consumed control oil, 0.7 g EPA+DHA/d (0.7FO), and 1.8 g EPA+DHA/d (1.8FO) capsules in random order, each for an 8-wk intervention period, separated by 12-wk washout periods., Results: In the group as a whole, 8% and 11% lower plasma triacylglycerol concentrations were evident after 0.7FO and 1.8FO, respectively (P < 0.001): significant sex x treatment (P = 0.038) and sex x genotype x treatment (P = 0.032) interactions were observed, and the greatest triacylglycerol-lowering responses (reductions of 15% and 23% after 0.7FO and 1.8FO, respectively) were evident in APOE4 men. Furthermore, lower VLDL-cholesterol (P = 0.026) and higher LDL-cholesterol (P = 0.010), HDL-cholesterol (P < 0.001), and HDL2 (P < 0.001) concentrations were evident after fish-oil intervention., Conclusions: Supplements providing EPA+DHA at doses as low as 0.7 g/d have a significant effect on the plasma lipid profile. The results of the current trial, which used a prospective recruitment approach to examine the responses in population subgroups, are indicative of a greater triacylglycerol-lowering action of long-chain n-3 polyunsaturated fatty acids in males than in females.

In the West of Scotland Coronary Prevention Study (WOSCOPS), treatment of hypercholesterolemic men with pravastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, reduced their likelihood to progress to diabetes mellitus by 30%. However, the mechanism of this effect of pravastatin has not been investigated. In the current study, we examined the effect of pravastatin on the development of diabetes in obese diabetic mice, and on the insulin-induced glucose uptake and adiponectin production. Pravastatin treatment attenuated the development of diabetes in db/db and high fat/high sucrose diet-fed C57BL/6J mice. An in vivo glucose transport assay showed that pravastatin upregulated glucose uptake in adipose tissue. Insulin-stimulated glucose uptake was enhanced in primary adipocytes isolated from pravastatin-treated mice. Pravastatin treatment increased adiponectin production in 3T3-L1 adipocytes. Plasma adiponectin levels were significantly increased in pravastatin-treated mice. Analyses of plasma samples from the WOSCOPS biobank indicated a significant increase of plasma adiponectin levels with pravastatin treatment (placebo -0.28+/-0.34 microg/ml versus pravastatin +1.47+/-0.33 microg/ml, p=0.0003). Taken together, our findings suggest that pravastatin may have beneficial effects on adipose tissue, which may partly explain the reduction of the development of diabetes by pravastatin treatment.

IDL is considered an atherogenic lipoprotein but little progress has been made on methods to subfractionate this density class. Furthermore, previous work suggests that lipoproteins retained by the arterial wall, of which chondoitin sulphate is the major arterial wall proteoglycan, are potentially atherogenic. The aim of this study was to assess the subfractionation of IDL particles using chondroitin sulphate (CS). Forty healthy subjects were recruited from laboratory staff and/or their partners. Fasted plasma samples were obtained and IDL (1.006 g/ml

Unlabelled: Prior moderate exercise has been shown consistently to reduce postprandial triglyceride (TG) concentrations in non-diabetic adults, but its effects in men with type 2 diabetes are not known. This study aimed to determine the effect of moderate exercise on postprandial metabolism in men with type 2 diabetes. Ten middle-aged men with type 2 diabetes underwent two oral fat tolerance tests (blood taken fasting and for 8 h after a meal containing 80 g fat, 70 g carbohydrate) in random order. On the afternoon before one test, participants performed a 90-min treadmill walk (Exercise); no exercise was performed before the CONTROL test. Exercise significantly reduced fasting glucose (, Control: 9.08+/-0.75 mmol l(-1), Exercise: 8.40+/-0.72 mmol l(-1), p=0.033) and insulin (, Control: 8.01+/-0.98 microU ml(-1), Exercise: 6.81+/-0.93 microU ml(-1), p=0.046) and increased fasting 3-hydroxybutyrate (, Control: 87.1+/-19.2 micromol l(-1), Exercise: 134.3+/-28.4 micromol l(-1), p=0.011); reduced postprandial insulin by 11.0% (p=0.04) and increased postprandial 3-hydroxybutyrate by 31.8% (p=0.03); but did not significantly change fasting or postprandial triglyceride or NEFA concentrations. However, the exercise-induced change in postprandial triglyceride concentration ranged from -32.3 to +28.3% and the exercise-induced change in fasting 3-hydroxybutyrate concentration (a marker of hepatic fatty acid oxidation) was highly correlated with the exercise-induced changes in fasting and postprandial triglyceride (r=0.68, p=0.03 for both). Thus, inter-individual variation in propensity to increase hepatic fatty acid oxidation following exercise may account for the considerable heterogeneity in triglyceride responses to moderate exercise observed in men with type 2 diabetes.

Isotopic tracer methods of determining triglyceride-rich lipoprotein (TRL) kinetics are costly, time-consuming, and labor-intensive. This study aimed to develop a simpler and cost-effective method of obtaining TRL kinetic data, based on the fact that chylomicrons compete with large VLDL (VLDL(1); S(f) = 60-400) for the same catalytic pathway. Ten healthy subjects [seven men; fasting triglyceride (TG), 44.3-407.6 mg/dl; body mass index, 21-35 kg/m(2)] were given an intravenous infusion of a chylomicron-like TG emulsion (Intralipid; 0.1 g/kg bolus followed by 0.1 g/kg/h infusion) for 75-120 min to prevent the clearance of VLDL(1) by lipoprotein lipase. Multiple blood samples were taken during and after infusion for separation of Intralipid, VLDL(1), and VLDL(2) by ultracentrifugation. VLDL(1)-apolipoprotein B (apoB) and TG production rates were calculated from their linear increases in the VLDL(1) fraction during the infusion. Intralipid-TG clearance rate was determined from its exponential decay after infusion. The production rates of VLDL(1)-apoB and VLDL(1)-TG were (mean +/- SEM) 25.4 +/- 3.9 and 1,076.7 +/- 224.7 mg/h, respectively, and the Intralipid-TG clearance rate was 66.9 +/- 11.7 pools/day. Kinetic data obtained from this method agree with values obtained from stable isotope methods and show the expected relationships with indices of body fatness and insulin resistance (all P < 0.05). The protocol is relatively quick, inexpensive, and transferable to nonspecialist laboratories.

Aim: The present clinical study tested the hypothesis that oil-rich fish consumption improves CHD risk factors., Methods: Forty-eight (16 men) non-obese, healthy adults aged 20-55, consumed 125 g/day of salmon for a 4-week period followed by a 4-week period with no-fish (41 completers). Subjects were instructed to maintain dietary and physical activity patterns during the period of study. Blood pressure, anthropometric, body composition and dietary information with fasting blood samples to determine traditional and novel CHD risk markers and plasma fatty acids were obtained before and after each period., Results: Compared to no-fish, eating salmon significantly decreased systolic, diastolic and mean arterial blood pressure by 4%, triglycerides by 15%, and LDL-cholesterol by 7%, and significantly increased HDL-cholesterol by 5% (P<0.05). The changes in blood pressure and lipids alone with salmon intake predict around a 25% reduction in CHD risk based on the PROCAM risk calculator. Plasma adiponectin demonstrated a trend towards improvement (8.39 micromol/L with salmon and 7.52 with no-fish; P=0.086) but no significant changes were found either in plasma leptin, glucose or insulin after salmon consumption., Conclusions: Daily consumption of salmon improves traditional risk predictors of CHD in non-obese subjects. Adiponectin may be involved but the impact on novel risk factors needs study in high-risk subjects.

Background: New dietary strategies to reduce cardiovascular disease (CVD) risk include the addition of fiber to the diet. The effect of soluble-fiber consumption derived from Plantago ovata husk on lipid risk factors in patients with CVD is unknown., Objective: We compared the effects of soluble fiber (P. ovata husk) with those of insoluble fiber (P. ovata seeds) on plasma lipid, lipoprotein, and apolipoprotein (apo) concentrations within a CVD secondary prevention program., Design: In a randomized, crossover, controlled, single-blind design, 28 men with CVD (myocardial infarction or stable angina) and an LDL-cholesterol concentration

Prior moderate exercise reduces postprandial triglyceride concentrations. Its effects on the concentrations, compositions and potential atherogenicity of lipoprotein subfractions were investigated in the present study. Twenty normoglycaemic middle-aged men each underwent two fat tolerance tests (blood taken fasting and for 8 h after a meal containing 80 g fat and 70 g carbohydrate). On the afternoon before one test, subjects performed a 90-min treadmill walk (exercise); no exercise was performed before the control test. Prior exercise significantly reduced postprandial concentrations of chylomicrons (Sf >400) by 28.6% (absolute reduction 14.6 mg dl(-1)), of large VLDL1 (Sf 60-400) by 34.4% (39.7 mg dl(-1)) and of small VLDL2 (Sf 20-60) by 23.0% (9.6 mg dl(-1)). Over 95% of VLDL1 and VLDL2 comprised apolipoprotein (apo) B100-containing particles. Exercise also reduced postprandial remnant-like lipoprotein cholesterol (by 35%) and triglyceride concentrations (by 29%). Postprandial apo CIII/apo B and apo E/apo B ratios in VLDL1 were lower following exercise. Postprandial cholesteryl ester/triglyceride ratios were lower in VLDL1 and VLDL2 and higher in HDL2 following exercise. These data suggest that the effect of prior moderate exercise on VLDL1 is quantitatively greater than its effect on chylomicrons and that, in addition to reducing lipoprotein concentrations, exercise induces compositional changes to lipoprotein species which are likely to influence their metabolism and atherogenicity.

Introduction: Glutathione S transferases (GST) are enzymes responsible for the metabolism of numerous xenobiotics and play a major cellular antioxidant role. Our aim was firstly, to examine the association between the GST M1/GST mu-1 (GSTM1) and GST T1/GST theta-1 (GSTT1) gene variants with markers of oxidative stress and inflammation in diabetic patients, and secondly to examine the association and potential interaction between these variants and cigarette smoking., Methods: Seven hundred and seventy-three Caucasian subjects with diabetes and 2592 Caucasian non-diabetic subjects were successfully genotyped. Plasma total antioxidant status, C-reactive protein (CRP), oxidized-LDL (Ox-LDL) and LDL-mean/peak particle diameter were recorded in the diabetes sample., Results: No association was seen between genotype and cardiovascular disease (CVD) risk. In the diabetic subjects, GSTT1-1 compared to GSTT1-0 subjects had significantly higher CRP (p=0.001), Ox-LDL (p=0.004) and smaller LDL particles (p=0.01). In subjects without CVD, there was a significant interaction between the GSTT1-1 variant and smoking in determining Ox-LDL (p=0.04). Furthermore, CVD risk was higher in smokers compared to non-smokers with GSTT1-1. No significant associations were observed by GSTM1. Within the non-diabetic sample, no association was observed between genotype and prospective coronary heart disease (CHD) risk. Of note, the frequency of the GSTT1-1 variant was significantly lower in the diabetes subjects compared to the non-diabetic sample (p=0.01)., Conclusions: This study demonstrates an association between the GSTT1-1 variant and markers of inflammation and lipid peroxidation. Furthermore this variant interacts with smoking to increase lipid peroxidation.

Familial combined hyperlipidaemia (FCHL) is a complex genetic disorder of unknown aetiology. Study of this human condition over many decades has been hampered by likely genetic heterogeneity. In order to find better phenotypic markers, we have characterised the structures of VLDL, IDL and LDL in the St. Thomas' Mixed Hyperlipidaemic (SMHL) rabbit--an animal model of FCHL in which the hyperlipidaemia is caused primarily by an increased production rate of apolipoprotein B (apoB)--containing lipoproteins-and compared them with those in the Watanabe Heritable Hyperlipidaemic (WHHL) rabbit, in which hyperlipidaemia is caused mainly by a defect in lipoprotein clearance, and those in the normolipidaemic New Zealand White (NZW) animal. All three rabbit strains were fed a cholesterol-enriched (0.08%, w/w) diet for at least 3 months prior to blood sampling. Both SMHL and WHHL rabbits showed combined hyperlipidaemia as evidenced by significantly increased levels of plasma cholesterol and triglycerides. Raised plasma lipids in the SMHL rabbit were attributable mainly to an overabundance of lipoprotein particles with the same lipid composition as those in NZW rabbits. VLDL and IDL in the SMHL rabbit showed a significantly increased sphingomyelin to phosphatidyl choline ratio. In the WHHL rabbit there was a high concentration of particles that were significantly enriched in cholesteryl esters and depleted in triglycerides. Phospholipids in all lipoprotein fractions from WHHL rabbits contained significantly more sphingomyelin and less phosphatidyl choline resulting in a significantly increased sphingomyelin to phosphatidyl choline ratio. We found that the VLDL of SMHL rabbits could be distinguished from that of NZW rabbits on the basis of the cholesterol:apoB and the sphingomyelin:phosphatidylcholine ratios, and from that of WHHL rabbits by the sphingomyelin:triglyceride ratio. Extrapolating these findings to the human condition, an assessment of particle core composition, together with the proportion of sphingomyelin in phospholipids especially in VLDL might help in the differentiation of the combined hyperlipidaemia of FCHL into disorders of lipoprotein overproduction versus decreased clearance.

The use of stable isotopes in conjunction with compartmental modeling analysis has greatly facilitated studies of the metabolism of the apolipoprotein B (apoB)-containing lipoproteins in humans. The aim of this study was to develop a multicompartment model that allows us to simultaneously determine the kinetics of apoB and triglyceride (TG) in VLDL(1) and VLDL(2) after a bolus injection of [(2)H(3)]leucine and [(2)H(5)]glycerol and to follow the catabolism and transfer of the lipoprotein particles. Here, we describe the model and present the results of its application in a fasting steady-state situation in 17 subjects with lipid values representative of a Western population. Analysis of the correlations showed that plasma TG was determined by the VLDL(1) and VLDL(2) apoB and TG fractional catabolic rate. Furthermore, the model showed a linear correlation between VLDL(1) TG and apoB production. A novel observation was that VLDL TG entered the circulation within 21 min after its synthesis, whereas VLDL apoB entered the circulation after 33 min. These observations are consistent with a sequential assembly model of VLDL and suggest that the TG is added to a primordial apoB-containing particle in the liver.

The aim of our work was to evaluate changes in levels of oxidised low-density lipoprotein (Ox-LDL) during pregnancy and how they correlate with changes in LDL size and serum total antioxidant status (TAS). LDL peak and mean particle diameter (LDL-PPD and LDL-MPD, respectively) and the relative proportion of 3 LDL subfractions were quantified. We evaluated plasma levels of Ox-LDL and serum levels of TAS, total cholesterol (Chol), triglycerides (TG), apolipoprotein A-I (apo A-I), apolipoprotein B (apo B), HDL-cholesterol (HDLc) and LDL-cholesterol (LDLc). A longitudinal study was performed in the three trimesters (T1-T3) of pregnancy in normal pregnant women (n = 23) and a non-pregnant group (n = 18) was used as control. TG levels were significantly elevated whereas LDL-MPD and LDL-PPD were significantly reduced in T1 compared to controls. Ox-LDL, TG, Chol, apo B and LDLc rose markedly throughout pregnancy with significant changes between each trimester; LDL-PPD, LDL-MPD and TAS levels decreased significantly from T1 to T3. Changes in LDL size and in Ox-LDL and TAS levels were more pronounced between T1 and T2 than between T2 and T3. HDLc and apo A-I reached peak concentration in T2 but decreased in T3. TG concentrations correlated inversely with LDL size and positively with Ox-LDL; Ox-LDL was positively and strongly correlated with LDLc. Moreover, relative changes in the levels of Ox-LDL correlated inversely with relative changes in LDL size and TAS between trimesters. In conclusion, during human gestation the change in LDL profile towards smaller species and the decrease in serum TAS are closely associated with increased levels of Ox-LDL. The exact physiological role of the increments in Ox-LDL during pregnancy remains to be clarified.

Insulin resistance is probably the defining feature of the metabolic syndrome and is an important determinant of plasma triglyceride (TG) concentrations. We sought to investigate whether insulin resistance influenced the metabolism of VLDL1 (Sf 60-400) and VLDL2 (Sf 20-60). Sixteen (eight men, eight women) middle-aged, normoglycaemic subjects participated. VLDL1and VLDL2 apolipoprotein (apo) B metabolism was followed using a deuterated leucine tracer and insulin resistance was estimated using homeostasis model assessment (HOMA). HOMA-estimated insulin resistance (HOMAIR) significantly and strongly correlated with the VLDL1 production rate (r = 0.69, P < 0.01) and VLDL1 apo B pool size (r = 0.59, P = 0.02), but these relationships were not evident for VLDL2. Conversely, HOMAIR was not significantly related to the fractional rate of transfer of VLDL1 to VLDL2 but was significantly related to the fractional rate of transfer from VLDL2 to IDL (r = 0.61, P = 0.01). HOMAIR was not significantly related to the fractional rate of direct catabolism for either VLDL1 or VLDL2. These results suggest a role for insulin resistance in the determination of hepatic VLDL1 production and highlight the independent regulation of VLDL1 and VLDL2 metabolism.

This randomised, double-blind, placebo-controlled crossover study evaluated the effects of rosuvastatin (40 mg/day for 8 weeks) on atherogenic apolipoprotein B-containing lipoprotein subfractions. Subjects, recruited based on raised plasma triglyceride (TG) or low-density lipoprotein cholesterol (LDL-C), were divided into normotriglyceridaemic (NTG, n = 13; TG < 2.0 mmol/l) and hypertriglyceridaemic (HTG, n = 16; TG > or = 2.0 mmol/l) groups. Similar reductions on rosuvastatin were observed for both groups in LDL-C (NTG -60%; HTG -56%), apoB (both -49%), intermediate-density lipoprotein (NTG -57%; HTG -54%) and LDL circulating mass (NTG -52%, HTG -58%) (all P < 0.001 versus placebo), i.e., these changes were phenotype independent. Phenotype dependency in response was observed in HTG relative to NTG in concentration of small dense LDL (LDL-III) (NTG -44%, P = NS; HTG -69%, P < 0.001), very-low-density lipoprotein1 (NTG -18%, P = NS; HTG 46%, P < 0.01), and remnant-like particle cholesterol (NTG -31%, P = NS; HTG -48%, P < 0.05). Rosuvastatin reduced cholesteryl ester transfer protein (CETP) by 33% in NTG and 37% in HTG (both P < 0.001); a reduction in cholesteryl ester transfer activity (-59%, P < 0.001) was observed in HTG only. Rosuvastatin therefore, in addition to lowering LDL and apoB-concentrations, largely corrected the TG and LDL abnormalities in subjects who had the propensity to develop the atherogenic lipoprotein phenotype., (Copyright 2003 Elsevier Ireland Ltd.)

Background: Existing methods for detecting small-dense low-density lipoprotein (SD-LDL) are either semiquantitative (e.g., gradient gel electrophoresis) or require specialised laboratory methods (e.g., density-gradient ultracentrifugation, DGU)., Methods: We report a method in which plasma was adjusted to a density (D) of 1.044 and 1.060 g/ml, respectively, in two tubes, both of which underwent ultracentrifugation (UC). A measure of SD-LDL apolipoprotein B (apo B) was obtained by subtraction of the apo B concentration in D>1.060 g/ml lipoproteins from that in D>1.044 g/ml lipoproteins to correct for apo B associated with lipoprotein (a) [Lp(a)]. This procedure was evaluated in paired plasma samples in healthy men (n=62) and in age-matched healthy women (n=74) and in age-matched primary dyslipidaemic men (n=72) and women (n=29) and compared with an established density-gradient ultracentrifugation (DGU) method., Results: The dyslipidaemic patients had either decreased high-density lipoprotein cholesterol (HDL-C) and/or increased triglycerides. In dyslipidaemic men, SD-LDL apo B level (23 [5-77] mg/dl) was significantly higher than in healthy men (P<0.001). In dyslipidaemic women, the SD-LDL apo B levels (11 [4-71] mg/dl) were significantly higher than in healthy women (7 [1-45] mg/dl; P<0.005). The concentration of SD-LDL apo B correlated inversely with HDL-C in both women (r=-0.280: P<0.005) and men (r=-0.464; P<0.0001) and positively with triglyceride concentration in both women (r=0.213; P<0.05) and men (r=0.592: P<0.0001). Correction for apo B in Lp(a) increased the analytical variation, which was 12% for apo B at D=1.044-1.060 g/ml and 9% for apo B measured at D>1.044 g/ml. Although the correlation between the new method and DGU results was high (r=0.830; P<0.0001, n=43), the concentration of apo B at D>1.044 g/ml correlated strongly with both corrected results (r=0.978; P<0.0001; n=237) and also with SD-LDL isolated using the DGU method (r=0.832; P<0.0001). Results at D>1.044 g/ml showed the expected correlations both with HDL-C (r=-0.465: P<0.0001) and triglycerides (r=0.526; P<0.0001)., Conclusions: The new method gave results consistent with earlier published findings using other techniques. Further simplification of the method using a single-density spin at D>1.044 g/ml appears feasible and may provide an easier quantitative method for clinical use.

Background: Replacing dietary saturated fatty acids (SFAs) with monounsaturated fatty acids (MUFAs) lowers LDL cholesterol, but the underlying mechanisms remain unclear., Objective: We assessed the effects of replacing dietary SFAs with MUFAs on concentrations and subclass distributions of VLDL, intermediate-density lipoprotein, LDL, and HDL and on VLDL apolipoprotein B kinetics., Design: Thirty-five moderately hypercholesterolemic, middle-aged volunteers consumed for 6 wk, in random order, diets containing low (L-MUFA; 7.8% of energy from MUFAs), moderate (M-MUFA; 10.3% from MUFAs), or high (H-MUFA; 13.7% from MUFAs) amounts of MUFAs. Fasting blood samples were taken from all subjects after each intervention. VLDL apolipoprotein B kinetic studies were performed in a subgroup after the L-MUFA and H-MUFA diets., Results: Plasma cholesterol concentrations decreased in a dose-dependent manner with increasing intakes of dietary MUFAs. This change was entirely accounted for by reduced LDL cholesterol (-0.20 and -0.49 mmol/L after the M-MUFA and H-MUFA diets, respectively, compared with the concentration after the L-MUFA diet; P for trend < 0.01). Plasma triacylglycerol and HDL cholesterol were not significantly affected by the dietary intervention, nor were the concentrations of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), or intermediate-density lipoprotein (S(f) 12-20). Production and catabolic rates for VLDL(1) and VLDL(2) were also unaffected. HDL and LDL subclass distributions were not significantly altered, but as a consequence of the overall LDL lowering, concentrations of atherogenic LDL-III were 25% lower after the H-MUFA diet than after the L-MUFA diet (P = 0.02)., Conclusion: The effects of replacing dietary SFAs with MUFAs on lipoprotein metabolism appear to be almost exclusively limited to the LDL density class.

Subjects with moderate combined hyperlipidemia (n=11) were assessed in an investigation of the effects of atorvastatin and simvastatin (both 40 mg per day) on apolipoprotein B (apoB) metabolism. The objective of the study was to examine the mechanism by which statins lower plasma triglyceride levels. Patients were studied on three occasions, in the basal state, after 8 weeks on atorvastatin or simvastatin and then again on the alternate treatment. Atorvastatin produced significantly greater reductions than simvastatin in low density lipoprotein (LDL) cholesterol (49.7 vs. 44.1% decrease on simvastatin) and plasma triglyceride (46.4 vs. 39.4% decrease on simvastatin). ApoB metabolism was followed using a tracer of deuterated leucine. Both drugs stimulated direct catabolism of large very low density lipoprotein (VLDL(1)) apoB (4.52+/-3.06 pools per day on atorvastatin; 5.48+/-4.76 pools per day on simvastatin versus 2.26+/-1.65 pools per day at baseline (both P<0.05)) and this was the basis of the 50% reduction in plasma VLDL(1) concentration; apoB production in this fraction was not significantly altered. On atorvastatin and simvastatin the fractional transfer rates (FTR) of VLDL(1) to VLDL(2) and of VLDL(2) to intermediate density lipoprotein (IDL) were increased significantly, in the latter instance nearly twofold. IDL apoB direct catabolism rose from 0.54+/-0.30 pools per day at baseline to 1.17+/-0.87 pools per day on atorvastatin and to 0.95+/-0.43 pools per day on simvastatin (both P<0.05). Similarly the fractional transfer rate for IDL to LDL conversion was enhanced 58-84% by statin treatment (P<0.01) LDL apoB fractional catabolic rate (FCR) which was low at baseline in these subjects (0.22+/-0.04 pools per day) increased to 0.44+/-0.11 pools per day on atorvastatin and 0.38+/-0.11 pools per day on simvastatin (both P<0.01). ApoB-containing lipoproteins were more triglyceride-rich and contained less free cholesterol and cholesteryl ester on statin therapy. Further, patients on both treatments showed marked decreases in all LDL subfractions. In particular the concentration of small dense LDL (LDL-III) fell 64% on atorvastatin and 45% on simvastatin. We conclude that in patients with moderate combined hyperlipidemia who initially have a low FCR for VLDL and LDL apoB, the principal action of atorvastatin and simvastatin is to stimulate receptor-mediated catabolism across the spectrum of apoB-containing lipoproteins. This leads to a substantial, and approximately equivalent, percentage reduction in plasma triglyceride and LDL cholesterol.

Small dense LDL is now emerging as an important risk factor for coronary artery disease. The amount of the LDL III has been reported to differ between ethnic groups. To investigate differences in the distribution of LDL subfractions between Korean and Scottish populations, we measured the plasma concentration and percent distribution of three major LDL subfractions in age-and sex-matched, middle aged, healthy 124 Korean and Scottish subjects (32 Korean men vs. 32 Scottish men; 30 Korean women vs. 30 Scottish women). Body mass index and waist circumference did not differ between the two ethnic groups. Total cholesterol and LDL cholesterol concentrations were higher in Scottish men compared with Korean men (P<0.01), while plasma triglyceride concentration was higher in Korean men and women (P<0.01 in men, P<0.05 in women). HDL cholesterol concentrations in both Korean men and women were lower than that of their Scottish counterparts (P<0.05 in men; P<0.001 in women). Korean men had lower concentrations of total LDL (242+/-65 vs. 325+/-122 mg/dl, P<0.01), LDL I (24+/-18 vs. 60+/-36 mg/dl, P<0.001) and LDL II (110+/-56 vs. 196+/-78 mg/dl, P<0.001). In contrast, LDL III concentration was markedly higher in Korean men (108+/-75 vs. 70+/-65 mg/dl, P<0.05). Likewise, the percent of LDL I (10.0+/-7.3 vs. 19.1+/-10.1%, P<0.001) and LDL II (47.2+/-20.7 vs. 60.1+/-10.9%, P<0.01) were lower in Korean men, while that of LDL III was higher (42.8+/-24.9 vs. 20.8+/-15.0%, P<0.001). In the female population, there were no differences in total LDL and LDL I concentrations between Korean and Scottish. LDL II concentration was lower in Korean women (106+/-53 vs. 151+/-57 mg/dl, P<0.01). Korean women showed a higher percent of LDL III (24.8+/-24.7 vs. 14.2+/-5.9%, P<0.05) and a lower LDL II (47.8+/-19.1 vs. 61.0+/-10.0%, P<0.01). Multiple linear regression revealed that plasma triglyceride concentration was the most important determinant of the LDL III subfraction concentration in Korean men and women and in Scottish men. In Korean men, the LDL III concentration rose linearly through the whole range of plasma triglyceride concentration, whereas in Scottish men, there was a threshold at 108 mg/dl triglyceride above which there was a positive association. Korean women showed the same pattern as Scottish men. We suggest that LDL concentrations and LDL subfraction distributions are regulated differently in these two ethnic groups. The different relationships between triglyceride and LDL III subfraction in Koreans versus Scots suggest that other factors, such as hepatic lipase or cholesteryl ester transfer protein may additionally play a role determining the LDL subfraction profile.

The aim of this study was to evaluate changes in lipids, apolipoproteins and lipoproteins in Portuguese pregnant women and their potential involvement in the pathophysiology of preeclampsia. A cross-sectional study was performed by collecting blood samples in the first (n=64), second (n=48) and third (n=67) trimesters and puerperium (n=32) of normal pregnancies. Samples from preeclamptic women were obtained in the third trimester (n=51) and in puerperium (n=26). As normal pregnancy progressed and triglyceride (TG) levels rose there was a decrease in low density lipoprotein (LDL) size, as measured by peak and mean particle diameter (MPD), with an increased proportion of atherogenic small dense LDL. Preeclamptic women exhibited, in the third trimester and puerperium, higher mean serum TG concentration and lower high density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apo A-I) levels compared with healthy pregnant women. In the third trimester, LDL-mean particle diameter (LDL-MPD) and LDL cholesterol-apolipoprotein B (LDLc-apo B) ratio were also significantly reduced in the pathologic group. We conclude that human gestation is associated with an 'atherogenic' lipid profile that is further enhanced in preeclampsia and that this profile may be a potential contributor to endothelial cell dysfunction.

Both defective LDL receptors (familial hypercholesterolaemia, FH) and mutations in apolipoprotein B (apoB) on LDL (familial defective apoB, FDB) give rise to a phenotype of elevated LDL cholesterol. We sought to compare the metabolic basis of the two conditions by examining apoB turnover in FDB and FH subjects. A group comprising three heterozygous and one homozygous FDB subjects were compared with five FH heterozygotes and 17 control subjects using a deuterated leucine tracer. Kinetic parameters were derived by multicompartmental modelling. FH heterozygotes had a reduced delipidation rate for VLDL, which led to a moderate increase in plasma triglyceride. Compared with controls and FH, the FDB subjects converted 44% less IDL to LDL. The LDL FCR was reduced to a similar extent in FDB and FH. In all subjects LDL plasma levels appeared to be regulated by the LDL FCR and the rate of production of small VLDL. We conclude that disturbances in IDL metabolism provide the basis for understanding why FDB is less severe than FH. Our findings suggest that an apoB-LDL receptor interaction is important in the IDL to LDL conversion.