Showing papers on "High-density lipoprotein published in 2008"
TL;DR: Using genome-wide association data from three studies and targeted replication association analyses in up to 18,554 independent participants, it is shown that common SNPs at 18 loci are reproducibly associated with concentrations of low-density cholesterol, high-density lipoprotein (HDL) cholesterol, and/or triglycerides.
Abstract: Blood concentrations of lipoproteins and lipids are heritable risk factors for cardiovascular disease. Using genome-wide association data from three studies (n = 8,816 that included 2,758 individuals from the Diabetes Genetics Initiative specific to the current paper as well as 1,874 individuals from the FUSION study of type 2 diabetes and 4,184 individuals from the SardiNIA study of aging-associated variables reported in a companion paper in this issue) and targeted replication association analyses in up to 18,554 independent participants, we show that common SNPs at 18 loci are reproducibly associated with concentrations of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and/or triglycerides. Six of these loci are new (P < 5 x 10(-8) for each new locus). Of the six newly identified chromosomal regions, two were associated with LDL cholesterol (1p13 near CELSR2, PSRC1 and SORT1 and 19p13 near CILP2 and PBX4), one with HDL cholesterol (1q42 in GALNT2) and five with triglycerides (7q11 near TBL2 and MLXIPL, 8q24 near TRIB1, 1q42 in GALNT2, 19p13 near CILP2 and PBX4 and 1p31 near ANGPTL3). At 1p13, the LDL-associated SNP was also strongly correlated with CELSR2, PSRC1, and SORT1 transcript levels in human liver, and a proxy for this SNP was recently shown to affect risk for coronary artery disease. Understanding the molecular, cellular and clinical consequences of the newly identified loci may inform therapy and clinical care.
1,380 citations
TL;DR: Lower plasma levels of HDL cholesterol due to heterozygosity for loss-of-function mutations in ABCA1 were not associated with an increased risk of ischemic heart disease, and the association between IHD and HDL cholesterol and genotype was unclear.
Abstract: Context Low levels of high-density lipoprotein (HDL) cholesterol are inversely related to cardiovascular risk. Whether this is a causal effect is unclear. Objective To determine whether genetically reduced HDL cholesterol due to heterozygosity for 4 loss-of-function mutations in ABCA1 cause increased risk of ischemic heart disease (IHD). Design, Setting, and Participants Three studies of white individuals from Copenhagen, Denmark, were used: the Copenhagen City Heart Study (CCHS), a 31-year prospective general population study (n = 9022; 28 heterozygotes); the Copenhagen General Population Study (CGPS), a cross-sectional general population study (n = 31 241; 76 heterozygotes); and the Copenhagen Ischemic Heart Disease Study (CIHDS), a case-control study (n = 16 623; 44 heterozygotes). End points in all 3 studies were recorded during the period of January 1, 1976, through July 9, 2007. Main Outcome Measures Levels of HDL cholesterol in the general population, cellular cholesterol efflux, and the association between IHD and HDL cholesterol and genotype. Results Heterozygotes vs noncarriers for 4 ABCA1 mutations (P1065S, G1216V, N1800H, R2144X) had HDL cholesterol levels of 41 mg/dL (interquartile range, 31-50 mg/dL) vs 58 mg/dL (interquartile range, 46-73 mg/dL), corresponding to a reduction in HDL cholesterol of 17 mg/dL (P Conclusion Lower plasma levels of HDL cholesterol due to heterozygosity for loss-of-function mutations in ABCA1 were not associated with an increased risk of IHD.
456 citations
TL;DR: There is still intense interest in therapeutically targeting HDL and macrophage cholesterol efflux pathways, via treatments with niacin, cholesterol ester transfer protein inhibitors, LXR activators and infusions of apoA‐1, phospholipids and peptides.
Abstract: Plasma high density lipoprotein (HDL) levels bear a strong independent inverse relationship with atherosclerotic cardiovascular disease. Although HDL has anti-oxidant, anti-inflammatory, vasodilating and anti-thrombotic properties, the central anti-atherogenic activity of HDL is likely to be its ability to remove cholesterol and oxysterols from macrophage foam cells, smooth muscle cells and endothelial cells in the arterial wall. To some extent, the pleotropic athero-protective properties of HDL may be related to its ability to promote sterol and oxysterol efflux from arterial wall cells, as well as to detoxify oxidized phospholipids. In cholesterol-loaded macrophages, activation of liver X receptors (LXRs) leads to increased expression of adenosine triphosphate (ATP) binding cassetter transporter (ABCA1), ATP binding cassetter transporter gene (ABCG1) and apoE and promotes cholesterol efflux. ABCA1 stimulates cholesterol efflux to lipid-poor apolipoproteins, whilst ABCG1 promotes efflux of cholesterol and oxysterols to HDL. Despite some recent setbacks in the clinical arena, there is still intense interest in therapeutically targeting HDL and macrophage cholesterol efflux pathways, via treatments with niacin, cholesterol ester transfer protein inhibitors, LXR activators and infusions of apoA-1, phospholipids and peptides.
402 citations
TL;DR: HDL and apoA-I exhibit an antiinflammatory effect on human monocytes by inhibiting activation of CD11b by acting through ABCA1, whereas HDL may act through several receptors.
Abstract: Objective— Whereas the anti–inflammatory effects of high-density lipoprotein (HDL) on endothelial cells are well described, such effects on monocytes are less studied. Methods and Results— Human mo...
394 citations
TL;DR: When apoA-I and apoB are kept constant, HDL-C and HDL particle size may confer risk at very high values, but this does not hold true for very high levels of apo A-I at fixed levels of HDL- C and apOB.
390 citations
TL;DR: The hypothesis that PsA may be associated with obesity, hypertension, dyslipidaemia and insulin resistance because of the shared inflammatory pathway is supported.
Abstract: Objective. To examine the distribution of traditional and novel risk factors of cardiovascular disease (CVD) in patients with PsA compared with healthy controls. Methods. We compared risk factors for CVD between 102 consecutive PsA patients and 82 controls, adjusting for BMI. We also assessed the role of inflammation on the CVD risk factor by using a BMI and high-sensitivity CRP (hsCRP)-adjusted model. Results. The BMI of PsA patients were significantly higher than healthy controls. After adjusting for the BMI, PsA patients still have a higher prevalence of diabetes mellitus (DM) [odds ratio (OR) 9.27, 95% CI 2.09, 41.09) and hypertension (OR 3.37, 95% CI 1.68, 6.72), but a lower prevalence of low high density lipoprotein (HDL) cholesterol (OR 0.16, 95% CI 0.07, 0.41). PsA patients have significantly increased systolic and diastolic blood pressures, insulin resistance and inflammatory markers (hsCRP and white cell count) compared to controls. PsA patients have higher HDL cholesterol and apolipoprotein (Apo) A1 levels; and lower total cholesterol (TC) and low density lipoprotein cholesterol levels; and a lower TC/HDL ratio. However, the Apo B level (P < 0.05), and the Apo B/Apo A1 ratio (P ¼ 0.07) were higher in PsA patients. Further adjustment for hsCRP level rendered the differences in the prevalence of hypertension and DM; the TC, and sugar levels; and white cell count non-significant between the two groups; while the differences in other parameters remained significant. Conclusion. These data support the hypothesis that PsA may be associated with obesity, hypertension, dyslipidaemia and insulin resistance because of the shared inflammatory pathway.
232 citations
TL;DR: In this paper, the authors investigated the relationship between lipid changes and progression of coronary atherosclerosis and found no effect of torcetrapib/atorvastatin on percent atheroma volume.
Abstract: Background—Despite favorable effects on high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol, the cholesteryl ester transfer protein inhibitor torcetrapib failed to slow atherosclerosis progression and increased mortality. We investigated the relationship between lipid changes and progression of coronary atherosclerosis. Methods and Results—Intravascular ultrasound was performed at baseline and follow-up in 910 participants randomized to torcetrapib/atorvastatin or atorvastatin monotherapy. The relationship between changes in lipoprotein levels and the primary intravascular ultrasound end point, change in percent atheroma volume, was investigated. Compared with atorvastatin monotherapy, torcetrapib raised HDL-C by 61%, lowered low-density lipoprotein cholesterol by 20%, raised serum sodium (0.44±0.14 mmol/L, P=0.02), and lowered serum potassium (0.11±0.02 mmol/L, P<0.0001). Despite substantial increases in HDL-C, no effect was found of torcetrapib on percent atheroma volume...
214 citations
TL;DR: Current data suggest that high-density lipoprotein possesses various properties beyond reverse cholesterol transport, however, many issues on the exact role of high- density lipop protein remain unknown.
Abstract: Purpose of review The most accepted property of high-density lipoprotein is reverse cholesterol transport. However, other beneficial actions may contribute to the antiatherogenic role of high-density lipoprotein. This review addresses the action of high-density lipoprotein beyond reverse cholesterol transport. Recent findings High-density lipoprotein cholesterol levels are inversely associated with coronary heart disease and other forms of vascular disease. Apart from transferring excess cholesterol to the liver, high-density lipoprotein exhibits favorable effects on oxidation, inflammation, thrombosis and endothelial function. Some of these actions are at least in part attributed to high-density lipoprotein-associated enzymes, such as paraoxonase and platelet-activating factor acetylhydrolase. However, high-density lipoprotein can become dysfunctional and proatherogenic under certain circumstances. Summary Current data suggest that high-density lipoprotein possesses various properties beyond reverse cholesterol transport. However, many issues on the exact role of high-density lipoprotein remain unknown. Future research is needed.
189 citations
TL;DR: It is concluded that the associations observed are likely to reflect true biological phenomena and the effect of CETP genes appeared to be limited to non‐smokers.
Abstract: Cholesteryl ester transfer protein (CETP) is a protein involved in "reverse cholesterol transport" and it could play an important role in facilitating the removal of cholesteryl esters from peripheral tissues for transport to the liver or for transfer of cholesterol between plasma lipoprotein particles. Both functions may be relevant to susceptibility or resistance to atherosclerotic disease. We have studied 149 and 146 unrelated persons, respectively, for the A and B polymorphism at the CETP locus detectable with the restriction enzyme TaqI. The B system is by far the more polymorphic. A search for association with risk or "anti-risk" factor levels was conducted with the following quantitative parameters: total cholesterol, HDL cholesterol, triglycerides, apolipoprotein AI (apoA-I), apolipoprotein B (apoB) and Lp(a) lipoprotein levels. Highly significant differences in apoA-I concentration were found between the two categories of homozygotes in the B polymorphism. The association observed remained significant after multiplying the p value by the number of quantitative parameters used for the association tests. There was a dosage effect on the apoA-I level of genes in the B polymorphism. We conclude that the associations observed are likely to reflect true biological phenomena. The effect of CETP genes appeared to be limited to non-smokers.
187 citations
TL;DR: The effect of apoM on atherosclerosis may be facilitated by enzymatic modulation of plasma HDL particles, increased cholesterol efflux from foam cells, and an antioxidative effect of ApoM-containing HDL.
176 citations
TL;DR: It is concluded that CD36 variants may impact MetS pathophysiology and HDL metabolism, both predictors of the risk of heart disease and type 2 diabetes.
Abstract: A region along chromosome 7q was recently linked to components of the metabolic syndrome (MetS) in several genome-wide linkage studies. Within this region, the CD36 gene, which encodes a membrane receptor for long-chain fatty acids and lipoproteins, is a potentially important candidate. CD36 has been documented to play an important role in fatty acid metabolism in vivo and subsequently may be involved in the etiology of the MetS. The protein also impacts survival to malaria and the influence of natural selection has resulted in high CD36 genetic variability in populations of African descent. We evaluated 36 tag SNPs across CD36 in the HyperGen population sample of 2020 African-Americans for impact on the MetS and its quantitative traits. Five SNPs associated with increased odds for the MetS [P = 0.0027-0.03, odds ratio (OR) = 1.3-1.4]. Coding SNP, rs3211938, previously shown to influence malaria susceptibility, is documented to result in CD36 deficiency in a homozygous subject. This SNP conferred protection against the MetS (P = 0.0012, OR = 0.61, 95%CI: 0.46-0.82), increased high-density lipoprotein cholesterol, HDL-C (P = 0.00018) and decreased triglycerides (P = 0.0059). Fifteen additional SNPs associated with HDL-C (P = 0.0028-0.044). We conclude that CD36 variants may impact MetS pathophysiology and HDL metabolism, both predictors of the risk of heart disease and type 2 diabetes.
TL;DR: Niacin markedly increases HDL-cholesterol in APOE*3Leiden.CETP mice by reducing CETP activity, as related to lower hepatic CETP expression and a reduced plasma (V)LDL pool, and increases LDL-apoAI by decreasing the clearance of apoAI from plasma.
Abstract: Objective - Niacin potently decreases plasma triglycerides and LDL-cholesterol. In addition, niacin is the most potent HDL-cholesterol- increasing drug used in the clinic. In the present study, we aimed at elucidation of the mechanism underlying its HDL-raising effect. Methods and Results - InAPOE*3Leiden transgenic mice expressing the human CETP transgene, niacin dose-dependently decreased plasma triglycerides (up to -77%, P<0.001) and total cholesterol (up to -66%, P<0.001). Concomitantly, niacin dose-dependently increased HDL-cholesterol (up to +87%, P<0.001), plasma apoAI (up to +72%, P<0.001), as well as the HDL particle size. In contrast, in APOE*3Leiden mice, not expressing CETP, niacin also decreased total cholesterol and triglycerides but did not increase HDL-cholesterol. In fact, in APOE*3Leiden.CETP mice, niacin dose-dependently decreased the hepatic expression of CETP (up to -88%; P<0.01) as well as plasma CETP mass (up to -45%, P<0.001) and CETP activity (up to -52%, P<0.001). Additionally, niacin dose-dependently decreased the clearance of apoAI from plasma and reduced the uptake of apoAI by the kidneys (up to -90%, P<0.01). Conclusion - Niacin markedly increases HDL-cholesterol in APOE*3Leiden. CETP mice by reducing CETP activity, as related to lower hepatic CETP expression and a reduced plasma (V)LDL pool, and increases HDL-apoAI by decreasing the clearance of apoAI from plasma. © 2008 American Heart Association, Inc.
TL;DR: Statins cause modest increases in HDL-C and apo A-I probably mediated by reductions in CETP activity, plausible that such changes independently contribute to the cardiovascular benefits of the statin class but more studies are needed to further explore this possibility.
Abstract: Purpose
The objective was to systematically review clinical trial data on the effects of statins on high-density lipoproteins (HDL) and to examine the possibility that this provides cardiovascular benefits in addition to those derived from reductions in low-density lipoproteins (LDL).
TL;DR: Raising HDL-C in patients with aggressively lowered LDL-C provides an additional strategy for addressing the residual cardiovascular risk present in these patients groups, and should lead to further improvements in clinical outcomes in these patient groups.
Abstract: The last 20 years have witnessed dramatic reductions in cardiovascular risk using 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins") to lower levels of low-density lipoprotein cholesterol (LDL-C). Using this approach one can achieve a reduction in the risk of major cardiovascular events of 21% for every 1 mmol/l (39 mg/dl) decrease in LDL-C. However, despite intensive therapy with high dose "statins" to lower LDL-C levels below 2.6 mmol/l (100 mg/dl), the risk of a major cardiovascular event in patients with established coronary artery disease remains significant at a level approaching an annual risk of 9%, paving the way for new strategies for reducing the residual cardiovascular risk in this patient group. Early epidemiological studies have identified low levels of high-density lipoprotein cholesterol (HDL-C) (<1.0 mmol/l or 40 mg/dl), a common feature of type 2 diabetes mellitus and the metabolic syndrome, to be an independent determinant of increased cardiovascular risk. The beneficial effects of HDL-C on the cardiovascular system have been attributed to its ability to remove cellular cholesterol, as well as its anti-inflammatory, antioxidant and antithrombotic properties, which act in concert to improve endothelial function and inhibit atherosclerosis, thereby reducing cardiovascular risk. As such, raising HDL-C in patients with aggressively lowered LDL-C provides an additional strategy for addressing the residual cardiovascular risk present in these patients groups. Studies suggest that for every 0.03 mmol/l (1.0 mg/dl) increase in HDL-C, cardiovascular risk is reduced by 2-3%. Raising HDL-C can be achieved by both lifestyle changes and pharmacological means, the former of which include smoking cessation, aerobic exercise, weight loss and dietary manipulation. Therapeutic strategies have included niacin, fibrates, thiazolidinediones and bile acid sequestrants. Newly developed pharmacological agents include apolipoprotein A-I mimetics and the cholesteryl ester transfer protein (CETP) inhibitors, JTT-705 and torcetrapib, the latter of which has been recently withdrawn from clinical testing because of serious adverse effects. Emerging experimental studies investigating the complex pathways of HDL metabolism have identified several new targets for raising HDL-C with new pharmaceutical agents currently in development. For the time being, the long-acting formulations of nicotinic acid remain the most effective and best tolerated pharmacological strategy for raising HDL-C in patients already on statin therapy to control LDL-C. Therefore, raising HDL-C represents an important strategy for reducing residual cardiovascular risk in patients already optimally treated with statins, and should lead to further improvements in clinical outcomes in these patient groups.
TL;DR: Results suggest that HIV infection is associated with modified HDL metabolism re-directing cholesterol to the apoB-containing lipoproteins and likely reducing the functionality of reverse cholesterol transport.
TL;DR: Genome-wide associations at the GCKR gene and near the SORT1 gene, as well as confirmatory associations at 5 additional novel loci, suggest emerging biological pathways for lipid metabolism among white women.
Abstract: Background— Genome-wide genetic association analysis represents an opportunity for a comprehensive survey of the genes governing lipid metabolism, potentially revealing new insights or even therape...
TL;DR: It is suggested that the TG/HDL cholesterol ratio was an imperfect surrogate for IR and its associated CHD risk, and it was only slightly better than the total/HDl cholesterol ratio for this purpose.
Abstract: Increased triglycerides (TG) and decreased high-density lipoprotein (HDL) cholesterol are key metabolic abnormalities in patients with insulin resistance (IR) states, including diabetes mellitus. The TG/HDL cholesterol ratio was advocated as a simple clinical indicator of IR, but studies yielded inconsistent results. The total cholesterol/HDL cholesterol ratio was widely used to assess lipid atherogenesis, but its utility for assessing IR or its associated coronary heart disease (CHD) risk was unknown. TG/HDL cholesterol and total cholesterol/HDL cholesterol ratios were related to IR (top quartile of the homeostasis model assessment-IR) in 3,014 patients (mean age 54 years; 55% women). Logistic regression was used to construct receiver-operator characteristic curves for predicting IR, with lipid ratios as predictors. Multivariable Cox regression was used to evaluate whether adjusting for lipid ratios attenuated the association of IR with CHD. Cross sectionally, age- and gender-adjusted correlations of IR were 0.46 with TG/HDL cholesterol ratio and 0.38 with total/HDL cholesterol ratio. IR prevalence increased across tertiles of lipid ratios (p
TL;DR: In this paper, the effects of extended-release niacin (2 g/d) plus lovastatin (40 mg/d), relative to placebo, on the kinetics of apolipoprotein (apo) A-I and apoA-II in HDL, apoB-100 in TG-rich lipoproteins (TRL), intermediate-density lipoproteinins (IDL) and low-density Lipoprotein (LDL) in TRL in 5 men with combined hyperlipidemia.
Abstract: Objectives— Extended-release niacin effectively lowers plasma TG levels and raises plasma high-density lipoprotein (HDL) cholesterol levels, but the mechanisms responsible for these effects are unclear. Methods and Results— We examined the effects of extended-release niacin (2 g/d) and extended-release niacin (2 g/d) plus lovastatin (40 mg/d), relative to placebo, on the kinetics of apolipoprotein (apo) A-I and apoA-II in HDL, apoB-100 in TG-rich lipoproteins (TRL), intermediate-density lipoproteins (IDL) and low-density lipoproteins (LDL), and apoB-48 in TRL in 5 men with combined hyperlipidemia. Niacin significantly increased HDL cholesterol and apoA-I concentrations, associated with a significant increase in apoA-I production rate (PR) and no change in fractional catabolic rate (FCR). Plasma TRL apoB-100 levels were significantly lowered by niacin, accompanied by a trend toward an increase in FCR and no change in PR. Niacin treatment significantly increased TRL apoB-48 FCR but had no effect on apoB-48 PR. No effects of niacin on concentrations or kinetic parameters of IDL and LDL apoB-100 and HDL apoA-II were noted. The addition of lovastatin to niacin promoted a lowering in LDL apoB-100 attributable to increased LDL apoB-100 FCR. Conclusion— Niacin treatment was associated with significant increases in HDL apoA-I concentrations and production, as well as enhanced clearance of TRL apoB-100 and apoB-48.
TL;DR: To find whether pretreatment of Ulva lactuca polysaccharide (ULP) extract could be effective against D-Galactosamine induced anomaly in rat, U.lactuca exhibit anti-peroxidative and anti-hyperlipidemic property.
TL;DR: The studies suggest that caveolin-1 plays an important role in the regulation of lipoprotein metabolism by controlling their plasma levels as well as their lipid composition, and may also play an importantrole in the development of atherosclerosis.
Abstract: Lipoprotein metabolism plays an important role in the development of several human diseases, including coronary artery disease and the metabolic syndrome. A good comprehension of the factors that regulate the metabolism of the various lipoproteins is therefore key to better understanding the variables associated with the development of these diseases. Among the players identified are regulators such as caveolins and caveolae. Caveolae are small plasma membrane invaginations that are observed in terminally differentiated cells. Their most important protein marker, caveolin-1, has been shown to play a key role in the regulation of several cellular signaling pathways and in the regulation of plasma lipoprotein metabolism. In the present paper, we have examined the role of caveolin-1 in lipoprotein metabolism using caveolin-1-deficient (Cav-1(-/-)) mice. Our data show that, while Cav-1(-/-) mice show increased plasma triglyceride levels, they also display reduced hepatic very low-density lipoprotein (VLDL) secretion. Additionally, we also found that a caveolin-1 deficiency is associated with an increase in high-density lipoprotein (HDL), and these HDL particles are enriched in cholesteryl ester in Cav-1(-/-) mice when compared with HDL obtained from wild-type mice. Finally, our data suggest that a caveolin-1 deficiency prevents the transcytosis of LDL across endothelial cells, and therefore, that caveolin-1 may be implicated in the regulation of plasma LDL levels. Taken together, our studies suggest that caveolin-1 plays an important role in the regulation of lipoprotein metabolism by controlling their plasma levels as well as their lipid composition. Thus caveolin-1 may also play an important role in the development of atherosclerosis.
TL;DR: The study of LPL genotypes confirms the existence of close interrelations between high density lipoprotein cholesterol and triglyceride pathways and the influence of these genotypes on CHD risk warrants further investigation.
Abstract: Lipoprotein lipase (LPL) is a key enzyme in lipoprotein metabolism and a major candidate gene for coronary heart disease (CHD). The authors assessed associations between 7 LPL polymorphisms and lipid fractions and CHD risk in population-based cohort, case-control, and cross-sectional studies published by January 2007. Meta-analyses of 22,734 CHD cases and 50,177 controls in 89 association studies focused on the relations of the T-93G (rs1800590), D9N (rs1801177), G188E, N291S (rs268), PvuII (rs285), HindIII (rs320), and S447X (rs328) polymorphisms to high density lipoprotein cholesterol, triglycerides, myocardial infarction, or coronary stenosis. Carriers of 9N or 291S had modestly adverse lipid profiles. Carriers of the less common allele of HindIII or of 447X had modestly advantageous profiles. The combined odds ratio for CHD among carriers was 1.33 (95% confidence interval (CI): 1.14, 1.56) for 9N, 1.07 (95% CI: 0.96, 1.20) for 291S, 0.89 (95% CI: 0.81, 0.98) for the less common HindIII allele, and 0.84 (95% CI: 0.75, 0.94) for 447X. For T-93G (odds ratio (OR) = 1.22, 95% CI: 0.98, 1.52) and PvuII (OR = 0.96, 95% CI: 0.89, 1.04), there were null associations with lipid levels or CHD risk; information on G188E was limited (OR = 2.80, 95% CI: 0.88, 8.87). The study of LPL genotypes confirms the existence of close interrelations between high density lipoprotein cholesterol and triglyceride pathways. The influence of these genotypes on CHD risk warrants further investigation.
TL;DR: There is a considerable heterogeneity of plasma lipid profile in overweight and obese people, and the emergence of glucose intolerance or a genetic predisposition to familial combined hyperlipidemia will further modify the plasma lipid phenotype in obese people.
Abstract: Obesity is associated with a 3-or-more-fold increase in the risk of fatal and nonfatal myocardial infarction (1,2,3,4,5,6). The American Heart Association has reclassified obesity as a major, modifiable risk factor for coronary heart disease (7). The increased prevalence of premature coronary heart disease in obesity is attributed to multiple factors (8,9,10). A principal contributor to this serious morbidity is the alterations in plasma lipid and lipoprotein levels. The dyslipidemia of obesity is commonly manifested as high plasma triglyceride levels, low high-density lipoprotein cholesterol (HDLc), and normal low-density lipoprotein cholesterol (LDLc) with preponderance of small dense LDL particles (7,8,9,10). However, there is a considerable heterogeneity of plasma lipid profile in overweight and obese people. The precise cause of this heterogeneity is not entirely clear but has been partly attributed to the degree of visceral adiposity and insulin resistance. The emergence of glucose intolerance or a genetic predisposition to familial combined hyperlipidemia will further modify the plasma lipid phenotype in obese people (11,12,13,14,15).
TL;DR: Combined statin and niacin therapy partially reverses the changes in the protein composition seen in HDL3 in coronary artery disease subjects, raising the possibility that quantifying the HDL proteome could provide insights into the therapeutic efficacy of antiatherosclerotic interventions.
Abstract: Background— Boosting low high-density lipoprotein (HDL) levels is a current strategy for preventing clinical events that result from cardiovascular disease. We previously showed that HDL3 of subjects with coronary artery disease is enriched in apolipoprotein E and that the lipoprotein carries a distinct protein cargo. This observation suggests that altered protein composition might affect the antiatherogenic and antiinflammatory properties of HDL. We hypothesized that an intervention that increases HDL levels—combined statin and niacin therapy—might reverse these changes. Methods and Results— HDL3 isolated from 6 coronary artery disease subjects before and 1 year after combination therapy was analyzed by liquid chromatography–Fourier transform–mass spectrometry. Alterations in protein composition were detected by spectral counting and confirmed with extracted ion chromatograms. We found that combination therapy decreased the abundance of apolipoprotein E in HDL3 while increasing the abundance of other mac...
TL;DR: The results suggest that suppression of atherosclerosis with pioglitazone therapy is linked to its ability to raise HDL cholesterol.
Abstract: Background— Measurement of carotid intima-media thickness (CIMT) has been validated as a measure of atherosclerosis and as a predictor of future cardiovascular events. Compared with glimepiride, pioglitazone has been shown to slow the progression of atherosclerosis measured by CIMT in patients with type 2 diabetes mellitus. Methods and Results— We evaluated individual cardiovascular risk factors as predictors of the change in CIMT produced by pioglitazone treatment by determining whether their addition to a baseline model resulted in loss of significance for the treatment effect on CIMT. Pioglitazone treatment led to improvement in levels of multiple cardiovascular risk markers, including high-sensitivity C-reactive protein, apolipoprotein B, apolipoprotein A1, high-density lipoprotein (HDL) cholesterol, triglyceride, insulin, and free fatty acid. At 24 weeks, there were significant differences in HDL cholesterol, triglyceride, total cholesterol, low-density lipoprotein cholesterol, insulin, body mass ind...
TL;DR: CETP activity in plasma from 30 alcoholics without severe liver damage and 16 control subjects was compared to test the hypothesis that a defect in cholesteryl ester transfer could be responsible for the alcohol‐induced alteration in cholesterol distribution between lipoproteins.
Abstract: Cholesteryl ester transfer protein (CETP) facilitates the transfer of cholesteryl esters from HDL to apoB-containing lipoproteins. Since alcoholics have high HDL cholesterol and low LDL cholesterol levels, a defect in cholesteryl ester transfer could be responsible for the alcohol-induced alteration in cholesterol distribution between lipoproteins. To test this hypothesis, we compared CETP activity in plasma from 30 alcoholics without severe liver damage and 16 control subjects. Plasma CETP activity was 28% lower in the alcoholics compared with the controls (P less than 0.001), while the teetotallers among the latter had slightly higher CETP activity than those who consumed alcohol in moderation. CETP activity increased slowly after ethanol withdrawal, but did not reach the control level within the 7-day observation period. A positive correlation was observed between plasma CETP activity and the LDL cholesterol HDL cholesterol ratio (r = 0.480, P less than 0.002), whereas CETP activity showed a negative correlation with HDL cholesterol level (r = -0.467, P less than 0.001). The results indicate that defective transfer of cholesteryl esters from HDL to LDL contributes to the high HDL cholesterol levels in alcoholics.
TL;DR: It is indicated that the ε2 and ε4 alleles have the reciprocal effects on plasma lipid, lipoprotein and apo E levels.
Abstract: A significantly lower frequency of the epsilon 2 allele and a significantly higher frequency of the epsilon 3 allele were found in the normolipidemic Japanese population than those in the normolipidemic Caucasian populations. We have compared plasma lipid variables among the apolipoprotein (apo) E phenotype groups and estimated the average effects of the three common alleles (epsilon 2, epsilon 3 and epsilon 4) on plasma lipid levels in normolipidemic subjects. Plasma triglyceride (TG), very low density lipoprotein (VLDL)-TG, VLDL-cholesterol (C) and apo E levels were high in the apo E3/2 group, intermediate in the apo E3/3 group and low in the apo E4/3 group, whereas plasma total cholesterol (TC), low density lipoprotein (LDL)-C and high density lipoprotein (HDL)-C levels were low in the apo E3/2 group, intermediate in the apo E3/3 group and high in the apo E4/3 group. Furthermore, the epsilon 2 allele had an effect to increase the TG, VLDL-TG, VLDL-C and apo E levels and decrease the TC, LDL-C and HDL-C levels, whereas the epsilon 4 allele had an effect opposite to the epsilon 2 allele. These results indicate that the epsilon 2 and epsilon 4 alleles have the reciprocal effects on plasma lipid, lipoprotein and apo E levels.
TL;DR: HDL modulates low‐density lipoprotein and cell membrane oxidation through the action of paraoxonase‐1 (PON1), which is one of the major mechanisms by which HDL is anti‐atherogenic.
Abstract: Aims High-density lipoprotein (HDL) protects against atherosclerosis development. Defective functioning of HDL in Type 2 diabetes may be one cause of increased cardiovascular disease associated with Type 2 diabetes. HDL modulates low-density lipoprotein and cell membrane oxidation through the action of paraoxonase-1 (PON1), which is one of the major mechanisms by which HDL is anti-atherogenic.
Methods We have compared the ability of HDL from Type 2 diabetic patients without coronary heart disease (CHD) (n = 36) to metabolize membrane lipid hydroperoxides with HDL from healthy control subjects (n = 19) and people with CHD but no diabetes (n = 37).
Results HDL from subjects with Type 2 diabetes and CHD metabolized 20% less membrane hydroperoxides than HDL from control subjects (P < 0.05). The PON1-192RR was least efficient in all the study groups. PON1 was glycated in vivo: (7.5% control, 12% CHD, 17% Type 2 diabetes P < 0.01) with QQ isoforms most glycated. In vitro glycation of PON1 reduced its ability to metabolize membrane hydroperoxides by 50% (P < 0.001); however, glyoxidation reduced it by 80% (P < 0.001). In the control group only there was a significant negative correlation between PON1 activity and the ability of HDL to metabolize membrane hydroperoxides (r = −0.911, P < 0.001).
Conclusions HDL from Type 2 diabetic patients without CHD has decreased ability to metabolize membrane lipid hydroperoxides, which could lead to increased susceptibility to cardiovascular disease.
TL;DR: Adiponectin might protect against atherosclerosis by increasing apoA-I-mediated cholesterol efflux from macrophages through ABCA1-dependent pathway by the activation of LXRalpha and PPARgamma.
TL;DR: A plasma protein that catalyzes the heteroexchange of cholesteryl esters from high‐density lipoprotein (HDL) and triglycerides to apolipoprotein B–containing lipoproteins, especially very low–density lipOProteins (LDL‐C).
Abstract: Cholesteryl ester transfer protein (CETP) is a plasma protein that catalyzes the heteroexchange of cholesteryl esters from high-density lipoprotein (HDL) and triglycerides to apolipoprotein B–containing lipoproteins, especially very low–density lipoproteins (LDL-C).1,2
Clinical Pharmacology & Therapeutics (2008); 84, 6, 679–683 doi:10.1038/clpt.2008.109