Lipoproteins, HDL – ABC CARDIOL

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Editorial

Antiinflammatory and Cardioprotective Effects of HDL-C: Association With Autoantibodies Against Oxidized LDL?

Estêvão Lanna Figueiredo et al. Ricardo Wang

The accumulation of lipoproteins containing apolipoprotein B (ApoB), mainly low-density lipoprotein (LDL), in the arterial intima has been attributed to one of the initial steps of atherogenesis. In other studies, oxidized LDL and macrophages are the main pathogenic factors for the development of atherosclerosis.^, In turn, there is increasing evidence of the protective role of autoantibodies against oxidized LDL (oxLDL-AboxLDL-Ab in atherogenesis, a fact that can be potentiated by high-density lipoprotein (HDL).^,

In this volume of Arquivos Brasileiros de Cardiologia, Nunez et al. evaluated the hypothesis that individuals with higher levels of HDL-C would have elevated levels of oxLDL-Ab. This is a cross-sectional study that included 193 consecutive healthy individuals aged ≥ 18 years and excluded patients with coronary artery disease (CAD), stroke, secondary causes of HDL elevation or reduction, use of lipid-lowering drugs, alcoholism, and smoking. The subjects underwent a detailed physical examination, blood pressure measurements and carotid ultrasound, in addition to biochemical analyzes of peripheral blood. Participants were divided into tertiles, according to HDL-C levels: low (80 mg/dL: n=63).

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Original Article

Discordance of Low-Density Lipoprotein Cholestrol and Non-High-Density Lipoprotein Cholestrol and Coronary Artery Disease Severity

Ozge Kurmus et al. Aycan Fahri Erkan Berkay Ekici Turgay Aslan Murat Eren

Abstract

Background:

A sizeable proportion of patients have discordant low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C).

Objectives:

We assessed the relationship between discordance of LDL-C and non-HDL-C and coronary artery disease (CAD) severity.

Methods:

We retrospectively evaluated the data of 574 consecutive patients who underwent coronary angiography. Fasting serum lipid profiles were recorded, SYNTAX and Gensini scores were calculated to establish CAD complexity and severity. We determined the medians for LDL-C and non-HDL-C to examine the discordance between LDL-C and non-HDL-C. Discordance was defined as LDL-C greater than or equal to the median and non-HDL-C less than median; or LDL-C less than median and non-HDL-C greater than or equal to median. A p value < 0.05 was accepted as statistically significant.

Results:

LDL-C levels were strongly and positively correlated with non-HDL-C levels (r = 0.865, p 22 were not different from group to group (p = 0.635, p = 0.733, p = 0.799, p = 0.891, respectively). Also, there was no statistically significant correlation between LDL-C and Gensini or SYNTAX scores in any of the discordant or concordant groups. Additionally, no correlation was found between non-HDL-C and Gensini or SYNTAX score.

Conclusions:

While there was discordance between LDL-C and non-HDL-C (15% of patients), there is no difference regarding CAD severity and complexity between discordant and concordant groups.

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Editorial

A New Marker of Myocardial Bridge?

Paolo Blanco Villela et al. Gláucia Maria Moraes de Oliveira

Myocardial bridges (MBs) have been associated with an increased incidence of cardiovascular events. Even though the pathophysiology of this association is still elusive, it seems to be related to the development of atherosclerosis. This hypothesis is based on changes in blood flow resulting from systolic compression of coronary arteries and leading to changes in arterial wall shear stress, which could act as a proatherogenic event affecting the endothelium of the arterial segment proximal to the MB.

Recently, Akishima-Fukasawa et al. assessed 150 autopsies of individuals without cardiovascular heart disease to verify the influence of MBs on the development of atherosclerosis. The authors found the occurrence of MBs in 93 hearts, and using computer-assisted histomorphometry, observed a higher frequency of luminal stenosis in segments proximal to the MB. Using a multiple comparison test, the authors showed a relation between the presence of risk factors like hypertension, diabetes, and dyslipidemia to a higher rate of stenosis affecting segments located 2.5 cm proximally to the MB. Despite the absence of MB flow evaluation, the authors documented an anatomical association between significant atherosclerotic lesions and the presence of MBs. We could speculate that this may be one of the explanations for the increased incidence of cardiovascular events in patients with MB.

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Original Article

Is Lipid Accumulation Product Associated with an Atherogenic Lipoprotein Profile in Brazilian Subjects?

Flavia De Conti Cartolano et al. Caroline Pappiani Maria Camila Prupper de Freitas Antonio M. Figueiredo Neto … Antônio Augusto Ferreira Carioca Nágila Raquel Teixeira Damasceno

Abstract

Background:

Lipid accumulation product (LAP), a simple and low-cost tool, is a novel biomarker of central lipid accumulation and represents a potential surrogate marker for atherogenic lipoprotein profile. However, its association with lipoprotein subfractions has not been described in the literature.

Objective:

To determine whether LAP index could be used as a marker of low- and high-density lipoprotein (LDL and HDL) size in Brazilian individuals.

Methods:

This cross-sectional study included patients (n = 351) of both sexes and age between 30-74 years. Clinical and sociodemographic data and family history of diseases were evaluated. Lipoprotein size, and levels of total cholesterol (TC), lipoproteins, apolipoprotein AI and B (APO AI/APO B), glucose, insulin, insulin resistance index (HOMA-IR) and non-esterified fatty acids (NEFA) were assessed in blood samples. LAP was calculated by the formulas [(waist circumference_[cm]-58) × (triglycerides_[mmol/L]) for women and (waist circumference _[cm]-65) × (triglycerides _[mmol/L]) for men]. The association between LAP and metabolic parameters were tested by linear trend (general linear model, GLM test) before and after multiple adjustments for potential confounders (sex, age, smoking, statin, fibrate, and hypoglycemic drugs) at significant level p < 0.05.

Results:

LAP was positively associated with TC, APO B, NEFA, glucose, insulin and HOMA-IR values, and negatively associated with HDL-C. Higher central lipid accumulation was corelated with higher percentage of intermediate HDL and of small LDL and HDL and less amount of large HDL. LDL size was also reduced in greater LAP index values. The negative impact of LAP was maintained after adjustment for multiple variables.

Conclusion:

LAP was robustly associated with atherogenic profile of lipoprotein subfractions, independently of multiple confounders.

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Original Article

p.Q192R SNP of PON1 seems not to be Associated with Carotid Atherosclerosis Risk Factors in an Asymptomatic and Normolipidemic Brazilian Population Sample

Daniel Zanetti Scherrer et al. Vanessa Helena de Souza Zago Isabela Calanca Vieira Eliane Soler Parra … Natália Baratella Panzoldo Fernanda Alexandre Rodrigo Secolin Jamal Baracat Eder Carlos Rocha Quintão Eliana Cotta de Faria

Background:

Evidences suggest that paraoxonase 1 (PON1) confers important antioxidant and anti-inflammatory properties when associated with high-density lipoprotein (HDL).

Objective:

To investigate the relationships between p.Q192R SNP ofPON1, biochemical parameters and carotid atherosclerosis in an asymptomatic, normolipidemic Brazilian population sample.

Methods:

We studied 584 volunteers (females n = 326, males n = 258; 19-75 years of age). Total genomic DNA was extracted and SNP was detected in the TaqMan^® SNP OpenArray^® genotyping platform (Applied Biosystems, Foster City, CA). Plasma lipoproteins and apolipoproteins were determined and PON1 activity was measured using paraoxon as a substrate. High-resolution β-mode ultrasonography was used to measure cIMT and the presence of carotid atherosclerotic plaques in a subgroup of individuals (n = 317).

Results:

The presence of p.192Q was associated with a significant increase in PON1 activity (RR = 12.30 (11.38); RQ = 46.96 (22.35); QQ = 85.35 (24.83) μmol/min; p < 0.0001), HDL-C (RR= 45 (37); RQ = 62 (39); QQ = 69 (29) mg/dL; p < 0.001) and apo A-I (RR = 140.76 ± 36.39; RQ = 147.62 ± 36.92; QQ = 147.49 ± 36.65 mg/dL; p = 0.019). Stepwise regression analysis revealed that heterozygous and p.192Q carriers influenced by 58% PON1 activity towards paraoxon. The univariate linear regression analysis demonstrated that p.Q192R SNP was not associated with mean cIMT; as a result, in the multiple regression analysis, no variables were selected with 5% significance. In logistic regression analysis, the studied parameters were not associated with the presence of carotid plaques.

Conclusion:

In low-risk individuals, the presence of the p.192Q variant ofPON1 is associated with a beneficial plasma lipid profile but not with carotid atherosclerosis.

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