Prospective study of coronary heart disease vs. HDL2, HDL3, and other lipoproteins in Gofman's Livermore Cohort

Laparoscopic gastric banding resolves the metabolic syndrome and improves lipid profile over five years in obese patients with body mass index 30-40 kg/m(2.)

BACKGROUND

Obesity, metabolic syndrome (MS) and dyslipidemia are independent risk factors for cardiovascular disease. Bariatric surgery is increasingly recognized as an effective intervention for improving each of these risk factors. There are sparse data on the long-term durability of metabolic changes associated with bariatric surgery, in particular with laparoscopic gastric banding (LGB). Our objective was to evaluate the durability of metabolic changes associated with LGB in nonmorbid obesity.

METHODS

Fifty obese patients (BMI 30-40) with ≥1 obesity-related comorbidity were prospectively followed for five years. At follow-up, subjects underwent fasting blood measures, including lipid NMR spectroscopy and standard lipid profile.

RESULTS

Forty-seven patients (45 female, mean age 43.8 years) completed four years follow-up (46 completed five years). Baseline BMI was 35.1 ± 2.6. Subjects exhibited mean weight loss of 22.3 ± 7.9 kg (22.9 ± 7.4%) at year one and maintained this (19.8 ± 10.2%) over five years. At baseline, 43% (20/47) of subjects met criteria for MS. This was reduced to 15% (7/47) at year one and remained reduced over five years (13%, 6/46) (p < 0.001). There were reductions in triglycerides (p < 0.001) and increases in HDL cholesterol (HDL-C, p < 0.001) and HDL particle concentration (p = 0.02), with a trend toward increased HDL particle size (p = 0.06) at year five. Changes in triglycerides and HDL-C were more prominent in patients with MS at baseline, but unassociated with weight loss or waist circumference. Changes in HDL particle size and concentration were not associated with MS status, weight loss, waist circumference, or statin use.

CONCLUSIONS

LGB produces significant weight loss, resolution of MS and changes in lipid profile suggestive of beneficial HDL remodeling. These changes persist five years following LGB.

Inflammation, lipid metabolism and cardiovascular risk in rheumatoid arthritis: A qualitative relationship?

Life expectancy in patients with rheumatoid arthritis (RA) is reduced compared to the general population owing to an increase in cardiovascular diseases (CVD) not fully explained by traditional cardiovascular risk factors. In recent years, interest has been focused on the alterations in lipid metabolism in relation to chronic inflammation as one of the possible mechanisms involved in the pathogenesis of atherosclerosis of RA patients. Research regarding this issue has revealed quantitative alterations in lipoproteins during the acute-phase reaction, and has also demonstrated structural alterations in these lipoproteins which affect their functional abilities. Although many alterations in lipid metabolism have been described in this regard, these structural changes associated with inflammation are particularly important in high-density lipoproteins as they affect their cardioprotective functions. In this respect, excessive oxidation in low-density lipoprotein (LDL) and increased lipoprotein(a) with a predominance of smaller apolipoprotein(a) isoforms has also been reported. This article will discuss proinflammatory high-density lipoproteins (piHDL), oxidized LDL and lipoprotein(a). Elevated concentrations of these lipoproteins with marked pro-atherogenic properties have been observed in RA patients, which could help to explain the increased cardiovascular risk of these patients.

Associations of the Baltic Sea diet with cardiometabolic risk factors – a meta-analysis of three Finnish studies

Dyslipidaemia, hypertension and low-grade inflammation increase the risk of CVD. In the present meta-analysis, we examined whether adherence to a healthy Nordic diet, also called the Baltic Sea diet, may associate with a lower risk of these cardiometabolic risk factors. In 2001–2007, three cross-sectional Finnish studies were conducted: the Dietary, Lifestyle and Genetic Determinants of Obesity and Metabolic Syndrome study (n4776); Health 2000 Survey (n5180); Helsinki Birth Cohort Study (n1972). The following parameters were assessed in these three studies: blood pressure, total, HDL- and LDL-cholesterol, TAG and high-sensitivity C-reactive protein (hs-CRP); a validated FFQ was used to assess the participants' dietary intakes. The Baltic Sea Diet Score (BSDS) was developed based on the healthy Nordic diet. All studies assessed confounding variables, such as physical activity and BMI, based on standardised questionnaires and measurements. The random-effects meta-analysis provided summary estimates for OR and 95 % CI by the BSDS quintiles. In the meta-analysis, the risk of elevated hs-CRP concentration was lower among men (OR 0·58, 95 % CI 0·43, 0·78) and women (OR 0·73, 95 % CI 0·58, 0·91) in the highest BSDS quintile than among those in the lowest BSDS quintile. In contrast, the risk of lowered HDL-cholesterol concentration was higher among women (OR 1·67, 95 % CI 1·12, 2·48) in the highest BSDS quintile than among those in the lowest BSDS quintile. However, no other associations were found. In conclusion, the associations between the adherence to the healthy Nordic diet and cardiometabolic risk factors are equivocal. Longitudinal studies are needed to further examine this hypothesis.

Dusty punch cards and an eternal enigma: high-density lipoproteins and atherosclerosis

Epidemiological, clinical, and experimental evidence has accumulated during the last decades suggesting that high-density lipoproteins (HDLs) may protect from atherosclerosis and its clinical consequences. However, more than 55 years after the first description of the link between HDL and heart attacks, many facets of the biochemistry, function, and clinical significance of HDL remain enigmatic. This applies particularly to the completely unexpected results that became available from some recent clinical trials of nicotinic acid and of inhibitors of cholesteryl ester transfer protein (CETP). The concept that raising HDL cholesterol by pharmacological means would decrease the risk of vascular disease has therefore been challenged.

Association between high-normal levels of alanine aminotransferase and risk factors for atherogenesis

BACKGROUND & AIMS

Liver disease has been associated with cardiovascular disorders, but little is known about the relationship between serum levels of alanine aminotransferase (ALT) and markers of atherogenesis. We investigated the relationship between low-normal and high-normal levels of ALT and an extended panel of cardiovascular risk factors among individuals with no known diseases in a primary care setting.

METHODS

We performed a retrospective analysis of data collected from 6442 asymptomatic patients at wellness visits to a primary care setting in central Virginia from 2010 through 2011. Serum levels of ALT were compared with levels of lipids and lipoproteins, as well as metabolic, inflammatory, and coagulation-related factors associated with risk for cardiovascular disease.

RESULTS

Serum levels of ALT were higher than 40 IU/L in 12% of subjects, and in the high-normal range (19-40 IU/L in women and 31-40 IU/L in men) in 25% of subjects. ALT level was associated with the apolipoprotein B level, concentration and particle size of very-low-density lipoproteins, concentration of low-density lipoprotein (LDL) particles (LDL-P), and percentages of small dense LDL (sdLDL) and sdLDL-cholesterol (sdLDL-C) (P < .0001 for all). A high-normal level of ALT was associated with higher levels of LDL-C, LDL-P, sdLDL-C, and sdLDL particles (P < .001 for all). These effects were independent of age, body mass index, and hyperinsulinemia. Increasing levels of ALT and fasting hyperinsulinemia (>12 μU/mL) synergized with increasing levels of triglycerides, very-low-density lipoprotein particles, LDL-P, sdLDL-C, and percentage of sdLDL-C. Levels of APOA1, high-density lipoprotein-cholesterol, and high-density lipoprotein-class 2 were associated inversely with serum level of ALT (P < .0001 for all).

CONCLUSIONS

In an analysis of asymptomatic individuals, increased serum levels of ALT (even high-normal levels) are associated with markers of cardiovascular disease.

Paraoxonases: ancient substrate hunters and their evolving role in ischemic heart disease

Interest in the role of paraoxonases (PON) in cardiovascular research has increased substantially over the past two decades. These multifaceted and pleiotropic enzymes are encoded by three highly conserved genes (PON1, PON2, and PON3) located on chromosome 7q21.3-22.1. Phylogenetic analysis suggests that PON2 is the ancient gene from which PON1 and PON3 arose via gene duplication. Although PON are primarily lactonases with overlapping, but distinct specificities, their physiologic substrates remain poorly characterized. The most interesting characteristic of PON, however, is their multifunctional roles in various biochemical pathways. These include protection against oxidative damage and lipid peroxidation, contribution to innate immunity, detoxification of reactive molecules, bioactivation of drugs, modulation of endoplasmic reticulum stress, and regulation of cell proliferation/apoptosis. In general, PON appear as "hunters" of old and new substrates often involved in athero- and thrombogenesis. Although reduced PON activity appears associated with increased cardiovascular risk, the correlation between PON genotype and ischemic heart disease remains controversial. In this review, we examine the biochemical pathways impacted by these unique enzymes and investigate the potential use of PON as diagnostic tools and their impact on development of future therapeutic strategies.

Lipoprotein subfractions by ion mobility in lean and obese children

OBJECTIVE

To establish normative data for lipoprotein subfractions using a novel ion mobility assay in healthy lean children and to compare their data with those of obese children preselected with normal glucose, blood pressure, and relatively normal lipids.

STUDY DESIGN

Fasting blood samples in 162 children aged 7.0-18.9 years (75 lean [body mass index: 18.6 ± 6.6 kg/m(2)] and 87 obese [body mass index: 31.7 ± 5.4 kg/m(2)]) were analyzed. Correlation of lipoprotein subfractions with anthropometric and laboratory markers was performed. Principal component analysis was used to avoid using correlated variables.

RESULTS

Normative data for lipid subfractions were obtained in healthy children. Lean children had higher high-density lipoprotein (HDL)-large (76%), HDL-small (13%), and HDL-total (27%) compared with obese (P < .01), and lower low-density lipoprotein (LDL)-medium (-30%, P < .01) and medium + small (-21%, P = .02) as well as LDL-total (-13%, P = .035). In both groups, the LDL component was higher in males and pubertal children (P < .01). Prepubertal children had a higher HDL component than pubertal ones (P < .004). Adjusting for sex and pubertal status LDL component was positively, and HDL component negatively, correlated with obesity (P < .004).

CONCLUSIONS

Despite relatively normal triglycerides and cholesterol measured with standard assays at screening, ion mobility analysis showed significant differences in lipid and apolipoprotein subfractions between lean and obese children, even those prepubertal. Long-term, prospective follow-up may better characterize the predictability of lipid subfractions for future cardiovascular disease risk in children.

Changes of metabolic and inflammatory markers in HIV infection: glucose, lipids, serum Hs-CRP and myeloperoxidase

OBJECTIVE

HIV infection is exacerbated through additional pro-atherogenic mechanisms related to the processes of immune activation, inflammation, coagulation, and the modification of lipoproteins (e.g., particles of high density lipoprotein), contributing to increased cardiovascular risk. The aim of this study was to analyze the serum concentrations of myeloperoxidase (MPO) and other laboratory parameters in HIV-infected patients treated or not with antiretroviral drugs compared to non-infected individuals.

MATERIALS/METHODS

The study included 154 volunteers: 47 non-infected individuals (control group - CON), 27 infected and untreated individuals (NTARV group) and 80 treated individuals (TARV group). We analyzed the counts of CD4+ lymphocytes and the viral load of the infected patients, along with the blood count, fasting glucose, total serum cholesterol (CHOL), HDL cholesterol, LDL cholesterol, triglycerides, MPO and high-sensitivity C-reactive protein (CRP) of all study participants.

RESULTS

There were significant increases in glucose, CHOL, LDL cholesterol, and triglycerides in the TARV group and significant reductions in the levels of HDL cholesterol for the TARV and NTARV groups. Significantly elevated levels of Hs-CRP were observed only in the TARV group, while levels of MPO were significantly higher in the TARV and NTARV groups compared to the control group. A correlation of MPO with Hs-CRP (r=0.21, p=0.032) was observed for HIV-infected patients, but MPO did not correlate significantly with the other analyzed parameters.

CONCLUSIONS

The investigation of early biomarkers for cardiovascular risk evaluation, such as MPO, contributes to the clinical monitoring of HIV-infected individuals. The serum levels of MPO correlated with Hs-CRP and were high in HIV-infected individuals, indicating a possible predictor of cardiovascular events in these patients.

High-density lipoprotein and atherosclerosis: the role of antioxidant activity

Levels of high-density lipoprotein (HDL) cholesterol are generally inversely associated with the risk for the development of atherosclerosis. The mechanism by which HDL imparts protection from the initiation and progression of occlusive vascular disease is complex and multifactorial. The major anti-atherosclerotic effect of HDL is felt to be reverse cholesterol transport. HDL has been demonstrated to scavenge cholesterol from the peripheral vasculature with transport to the liver, where is it excreted in the biliary system. However, HDL exhibits multiple other physiologic effects that may play a role in the reduced risk for atherosclerosis. HDL has been demonstrated to exhibit beneficial effects on platelet function, endothelial function, coagulation parameters, inflammation, and interactions with triglyceride-rich lipoproteins. Increasing amounts of clinical and experimental data have shown that HDL cholesterol has significant antioxidant effect that may significantly contribute to protection from atherosclerosis.

High-density lipoprotein cholesterol subfractions HDL2 and HDL3 are reduced in women with rheumatoid arthritis and may augment the cardiovascular risk of women with RA: a cross-sectional study

INTRODUCTION

Higher levels of high density lipoprotein (HDL) subfractions HDL3-chol and particularly HDL2-chol protect against cardiovascular disease (CVD), but inflammation reduces the HDL level and may impair its anti-atherogenic effect. Changed HDL composition through the impact of inflammation on HDL subfractions may contribute to the excess risk of CVD in rheumatoid arthritis (RA). In this study, we investigated whether HDL2-chol and HDL3-chol concentrations differ between RA patients and healthy controls, and whether these levels are related to the level of RA disease activity.

METHODS

Non-fasting blood samples were collected from 45 RA patients and 45 healthy controls. None of the participants had a history of CVD, diabetes, or used lipid-lowering drugs. HDL2-chol and HDL3-chol concentrations were obtained by ultracentrifugation. Regression modeling was used to compare HDL subfraction levels between RA patients and healthy controls, and to analyze the effect of disease activity on HDL2-chol and HDL3-chol.

RESULTS

HDL2-chol and HDL3-chol were significantly lower in RA patients compared to healthy controls (P = 0.01, P = 0.005, respectively). The HDL2:HDL3 ratio was significantly lower in patients compared to controls (P = 0.04). Reduced HDL2-chol and HDL3-chol levels were primarily present in female RA patients and not in male RA patients. A modest effect of the disease activity score in 28 joins ( DAS28) on HDL2-chol concentrations was found, after correction for disease duration, glucocorticosteroid use and body mass index (BMI), with a 0.06 mmol/L decrease with every point increase in DAS28 (P = 0.05). DAS28 did not significantly affect HDL3-chol concentrations (P = 0.186).

CONCLUSIONS

Both HDL subfractions but particularly HDL2-chol concentrations were decreased in RA, primarily in women. This seems to be associated with disease activity and is of clinical relevance. The reduction of the HDL subfraction concentrations, particularly the supposedly beneficial HDL2-chol, may negatively impact the cardiovascular risk profile of women with RA.

High-density lipoprotein subclasses and their relationship to cardiovascular disease

OBJECTIVE

To assess the clinical utility of measuring high-density lipoprotein (HDL) subfractions to assess coronary heart disease (CHD) risk.

METHODS

Literature review of 80 published investigations.

RESULTS

Measurements of HDL2b by gradient gel electrophoresis provided more consistent evidence of CHD risk than measurement of HDL2 cholesterol. Five of the seven studies that compared the extent or progression of atherosclerosis with gradient gel electrophoresis estimates of HDL subclasses (71%) assigned statistical significance to HDL2b. Ten of the 11 case-control comparisons (91%) reported lower HDL2b in cases. In contrast, of the 16 association studies relating HDL2 cholesterol and HDL3 cholesterol to extent of disease, five reported no significant relationships with either subfraction, two reported significant relationships with both HDL2 and HDL3 cholesterol, four reported significant relationships with HDL2 but not HDL3 cholesterol, and five reported relationships with HDL3 but not HDL2 cholesterol. Forty-five percent of the case-control comparisons reported that both HDL2 cholesterol and HDL3 cholesterol were significantly lower in cases than controls, 17% failed to find significance for either subfraction, and the remainder reported significantly lower values in cases for HDL2 cholesterol only (26%) or HDL3 cholesterol only (11%). On average, the case-control differences were similar for HDL2 (-0.12 ± 0.01 mmol/L) and HDL3 cholesterol (-0.10 ± 0.02 mmol/L), although relative to controls, the percent reduction was twice as great for HDL2 (-25.7 ± 2.9%) than HDL3 cholesterol (-12.1 ± 1.5%). Eight prospective studies were identified and four reported that both HDL2 and HDL3 predicted lower risk for CHD, one reported reductions in risk for HDL2 but not HDL3 cholesterol, and three reported reductions in risk for HDL3 but not HDL2 cholesterol. None of the prospective studies show that measurements of HDL cholesterol subfractions improve the identification of persons at risk.

CONCLUSIONS

HDL2 and HDL3 cholesterol do not distinguish cardioprotective differences between HDL subclasses. More extensive characterization of HDL particles by one or two dimensional gel electrophoresis, ion mobility, or ultracentrifugation may provide more specific information about CHD risk than the measurement of HDL cholesterol, HDL3 cholesterol, or HDL2 cholesterol.

Low high-density lipoprotein 3 reduces the odds of men surviving to age 85 during 53-year follow-up

OBJECTIVES

To identify high-density lipoprotein (HDL) subfractions associated with longevity in men.

DESIGN

Fifty-three-year prospective follow-up of Gofman's Livermore Cohort between 1954 and 2008.

SETTING

Lawrence Livermore National Laboratory.

PARTICIPANTS

One thousand one hundred forty-four men who consented to the study, had analytic ultracentrifuge measurements of lipoprotein subfractions at baseline, and were old enough at baseline to have survived to age 85 during follow-up.

MEASUREMENTS

Survival was determined according to participant contact, Social Security Death Index, and National Death Index.

RESULTS

Three hundred ninety men survived to 85 years old (34.1%). Survivors were less likely than nonsurvivors to be in the lowest HDL3 (% (standard error) 18.5% (2.0%) vs 27.3% (1.6%), P < .001) and HDL2 (22.1% (2.1%) vs 27.7% (1.6%), P = .04) quartiles. Logistic regression analyses showed that the lowest HDL3 quartile significantly predicted shorter longevity (P = .002), whereas the linear increases per mg/dL of HDL3 did not (P = .38), suggesting a risk threshold proximal to the 25th percentile. Men who were above the 25th HDL3 percentile had 70% greater odds of surviving until age 85 than those below this level, which persisted when adjusted for HDL2, very low-density lipoprotein (LDL), and standard risk factors. Proportional hazard analyses of survival before age 85 showed that being in the lowest HDL3 quartile increased age-adjusted cancer risk by 39% (P = .05) and noncancer risk by 23% (P = .04) when adjusted for other risk factors. Survivors also smoked less (mean ± SD 0.31 ± 0.48 vs 0.57 ± 0.56 packs/d, P < .001), had lower systolic (118.36 ± 11.08 vs 122.81 ± 13.55 mmHg, P < .001) and diastolic (70.61 ± 8.59 vs 73.14 ± 9.22 mmHg, P < .001) blood pressures and lower LDL mass (359.55 ± 80.42 vs 374.37 ± 86.10 mg/dL, P = .009) and total cholesterol concentrations (229.51 ± 43.21 vs 235.89 ± 45.40 mg/dL, P = .04) than nonsurvivors.

CONCLUSION

Low HDL3 reduces the odds of extended survival in men, independent of HDL2, other lipoproteins, and standard risk factors.

Clinical utility of inflammatory markers and advanced lipoprotein testing: advice from an expert panel of lipid specialists

The National Cholesterol Education Program Adult Treatment Panel guidelines have established low-density lipoprotein cholesterol (LDL-C) treatment goals, and secondary non-high-density lipoprotein (HDL)-C treatment goals for persons with hypertriglyceridemia. The use of lipid-lowering therapies, particularly statins, to achieve these goals has reduced cardiovascular disease (CVD) morbidity and mortality; however, significant residual risk for events remains. This, combined with the rising prevalence of obesity, which has shifted the risk profile of the population toward patients in whom LDL-C is less predictive of CVD events (metabolic syndrome, low HDL-C, elevated triglycerides), has increased interest in the clinical use of inflammatory and lipid biomarker assessments. Furthermore, the cost effectiveness of pharmacological intervention for both the initiation of therapy and the intensification of therapy has been enhanced by the availability of a variety of generic statins. This report describes the consensus view of an expert panel convened by the National Lipid Association to evaluate the use of selected biomarkers [C-reactive protein, lipoprotein-associated phospholipase A(2), apolipoprotein B, LDL particle concentration, lipoprotein(a), and LDL and HDL subfractions] to improve risk assessment, or to adjust therapy. These panel recommendations are intended to provide practical advice to clinicians who wrestle with the challenges of identifying the patients who are most likely to benefit from therapy, or intensification of therapy, to provide the optimum protection from CV risk.

Biological activities of HDL subpopulations and their relevance to cardiovascular disease

The concept of raising high-density lipoprotein (HDL) has been the focus of increasing attention as a strategy to reduce cardiovascular disease. HDL particles are, however, highly heterogeneous in structure, intravascular metabolism and biological activity. In this review, we describe major HDL subpopulations and discuss new findings on the antiatherogenic properties of HDL particles. Across the HDL subpopulation spectrum, small, dense, protein-rich HDLs display potent atheroprotective properties, which can be attributed to specific clusters of proteins and lipids; such activities can be compromised under conditions of atherogenic dyslipidemia. Comprehensive structural and compositional analyses of HDL may provide key information to identify subpopulations displaying specific biological functions and acquiring deficient functionality, with the potential to reveal novel biomarkers of cardiovascular risk and new pharmacological targets.

HDL Measures, Particle Heterogeneity, Proposed Nomenclature, and Relation to Atherosclerotic Cardiovascular Events

BACKGROUND

A growing body of evidence from epidemiological data, animal studies, and clinical trials supports HDL as the next target to reduce residual cardiovascular risk in statin-treated, high-risk patients. For more than 3 decades, HDL cholesterol has been employed as the principal clinical measure of HDL and cardiovascular risk associated with low HDL-cholesterol concentrations. The physicochemical and functional heterogeneity of HDL present important challenges to investigators in the cardiovascular field who are seeking to identify more effective laboratory and clinical methods to develop a measurement method to quantify HDL that has predictive value in assessing cardiovascular risk.

CONTENT

In this report, we critically evaluate the diverse physical and chemical methods that have been employed to characterize plasma HDL. To facilitate future characterization of HDL subfractions, we propose the development of a new nomenclature based on physical properties for the subfractions of HDL that includes very large HDL particles (VL-HDL), large HDL particles (L-HDL), medium HDL particles (M-HDL), small HDL particles (S-HDL), and very-small HDL particles (VS-HDL). This nomenclature also includes an entry for the pre-β-1 HDL subclass that participates in macrophage cholesterol efflux.

SUMMARY

We anticipate that adoption of a uniform nomenclature system for HDL subfractions that integrates terminology from several methods will enhance our ability not only to compare findings with different approaches for HDL fractionation, but also to assess the clinical effects of different agents that modulate HDL particle structure, metabolism, and function, and in turn, cardiovascular risk prediction within these HDL subfractions.