Dietary, lifestyle, and clinical predictors of lipoprotein-associated phospholipase A2 activity in individuals without coronary artery disease

The association between dietary patterns and the novel inflammatory markers platelet-activating factor and lipoprotein-associated phospholipase A2: a systematic review

CONTEXT

Atherosclerosis is a disease of chronic inflammation. Recent research has identified 2 novel inflammatory biomarkers: platelet-activating factor (PAF) and lipoprotein-associated phospholipase A2 (Lp-PLA2). Diet has been proposed as a mediator of inflammation, but to date, the focus for these novel biomarkers has been on individual foods and nutrients rather than overall dietary patterns.

OBJECTIVE

To systematically review the literature on the association between dietary patterns and PAF and Lp-PLA2.

DATA SOURCES

The PubMed, Embase, CINAHL, and Cochrane CENTRAL literature databases were searched.

DATA ANALYSIS

Study quality was evaluated using the Quality Criteria Checklist. Sixteen studies (n = 4 observational and n = 12 interventional) were included and assessed for associations between dietary patterns and PAF and Lp-PLA2.

CONCLUSION

Study quality varied from neutral (n = 10) to positive (n = 6). Mediterranean, heart healthy, and vegetarian dietary patterns were associated with improved levels of PAF and Lp-PLA2. Conversely, Western dietary patterns were less favorable. A range of well-established, healthier dietary patterns may lower inflammation and the risk of atherosclerosis. More well-designed studies are needed to confirm these findings and identify other dietary patterns that improve inflammation.

Moderate alcohol consumption and lipoprotein subfractions: a systematic review of intervention and observational studies

CONTEXT

Moderate alcohol consumption is associated with decreased risk of cardiovascular disease (CVD) and improvement in cardiovascular risk markers, including lipoproteins and lipoprotein subfractions.

OBJECTIVE

To systematically review the relationship between moderate alcohol intake, lipoprotein subfractions, and related mechanisms.

DATA SOURCES

Following PRISMA, all human and ex vivo studies with an alcohol intake up to 60 g/d were included from 8 databases.

DATA EXTRACTION

A total of 17 478 studies were screened, and data were extracted from 37 intervention and 77 observational studies.

RESULTS

Alcohol intake was positively associated with all HDL subfractions. A few studies found lower levels of small LDLs, increased average LDL particle size, and nonlinear relationships to apolipoprotein B-containing lipoproteins. Cholesterol efflux capacity and paraoxonase activity were consistently increased. Several studies had unclear or high risk of bias, and heterogeneous laboratory methods restricted comparability between studies.

CONCLUSIONS

Up to 60 g/d alcohol can cause changes in lipoprotein subfractions and related mechanisms that could influence cardiovascular health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 98955.

Atherosclerosis and Inflammatory Bowel Disease-Shared Pathogenesis and Implications for Treatment

Atherosclerosis and inflammatory bowel disease (IBD) are often regarded as 2 distinct entities. The commonest manifestation of atherosclerosis is ischemic heart disease (IHD), and an association between IHD and IBD has been reported. Atherosclerosis and IBD share common pathophysiological mechanisms in terms of their genetics, immunology, and contributing environmental factors. Factors associated with atherosclerosis are implicated in the development of IBD and vice versa. Therefore, treatments targeting the common pathophysiology pathways may be effective in both conditions. The current review considers the pathophysiological pathways that are shared between the 2 conditions and discusses the implications for treatment and research.

The relationship between dietary patterns and lipoprotein-associated phospholipase A2 levels in adults with cardiovascular risk factors: Tehran Lipid and Glucose Study

Background:

Pathogenesis of cardiovascular diseases (CVDs) may be indicated by lipoprotein-associated phospholipase A2 (Lp-PLA2), serving as an inflammatory biomarker. However, the general dietary predictors of Lp-PLA2 have not been investigated so far. The aim of the present study is to investigate the relationship between the serum levels of Lp-PLA2 and dietary patterns in adults with cardiovascular risk factors.

Materials and Methods:

Dietary patterns extracted using factor analysis and serum levels of Lp-PAL2 in 470 adults aged 40–70 years who participated in the 5^th phase of the Tehran Lipid and Glucose Study (2011–2014) were determined. Associations between the dietary patterns and serum levels of Lp-PAL2 considering some confounder factors were evaluated.

Results:

The results showed that Western and semi-Mediterranean dietary patterns had significant effects on changes in Lp-PLA2 levels in univariate analyses. In multivariate analyses, after adjusting for age, sex, total cholesterol, low-density lipoprotein cholesterol, body mass index and physical activity, energy intake, hormone therapy for women, and taking blood lipid-lowering drugs as potential confounders, the Western dietary pattern remained a significant factor influencing the Lp-PLA2 level (β value: 1.65, 95% confidence interval: 1.12, 1.89; P < 0.05). Moreover, after adjustment for the mentioned confounder factors, the effect of the semi-Mediterranean dietary pattern on Lp-PLA2 disappeared.

Conclusion:

It can be concluded that the Western dietary pattern is associated with higher Lp-PLA2 levels. We recommend that adults eat less carbonated drinks, fast foods, salty snacks, mayonnaise, and organ meat to counteract increased serum Lp-PLA2 levels, which are directly associated with vascular inflammation and CVDs.

Energy Intake and Plasma Adiponectin as Potential Determinants of Lipoprotein-Associated Phospholipase A2 Activity: A Cross-Sectional Study

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂ ) is associated with increased risk of cardiovascular diseases (CVD) and type 2 diabetes mellitus. Lp-PLA₂ activity is positively associated with male sex, Caucasian race, the presence of metabolic syndrome (MetS) and low-density lipoprotein (LDL)-cholesterol, but it is negatively associated with high-density lipoprotein (HDL)-cholesterol. Associations with other cardiometabolic risk factors, inflammation markers, and lifestyle factors are few or inconsistent. We investigated potential determinants of Lp-PLA₂ activity among both nonmodifiable and modifiable CVD risk factors in a middle-aged Greek cohort without overt CVD. Two hundred eighty four subjects (159 men, 53 ± 9 years and 125 women 52 ± 9 years) participated in a cross-sectional study carried out during 2011-2012 in Athens, Attica. Cardiometabolic risk factors, inflammation markers, lifestyle factors, and Lp-PLA₂ activity were evaluated with established methods. The American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) criteria were used to define MetS. Lp-PLA₂ activity was not associated with MetS, but was associated with MetS components, markers of liver function, and macronutrient intake. Increased total energy intake was associated with increased Lp-PLA₂ activity (odds ratio, 95% confidence interval: 1.07, 1.01-1.14 and 1.10, 1.03-1.16 for the 4th and 3rd quartiles, respectively, compared to the 1st quartile) after adjustments for sex, pack-years of smoking, LDL-cholesterol, and statin treatment. Adiponectin tended to be inversely associated with Lp-PLA₂ activity (0.91, 0.82-1.00, and 4th versus 1st quartile). Our results suggested that total energy intake and adiponectin levels are potential determinants of Lp-PLA₂ activity.

Tracking of secretory phospholipase A2 enzyme activity levels from childhood to adulthood: a 21-year cohort

OBJECTIVE

Secretory phospholipase A2 (sPLA2) enzyme activity is a potential inflammatory biomarker for cardiovascular disease. We examined the tracking, or persistence, of sPLA2 enzyme activity levels from childhood to adulthood, and identify potentially modifiable factors affecting tracking.

METHOD

Prospective cohort of 1735 children (45% females) who had serum sPLA2 enzyme activity levels and other cardiovascular disease risk factors measured in 1980 that were followed-up in 2001.

RESULTS

sPLA2 activity tracked from childhood to adulthood for males (r=0.39) and females (r=0.45). Those who decreased body mass index relative to their peers were more likely to resolve elevated childhood sPLA2 levels than have persistent elevated sPLA2 levels in childhood and adulthood. Those who consumed less fruit, and gained more body mass index relative to their peers, began smoking or were a persistent smoker between childhood and adulthood were more likely to develop incident elevated sPLA2 levels than those with persistent not elevated sPLA2 levels.

CONCLUSIONS

Childhood sPLA2 enzyme activity levels associate with adult sPLA2 levels 21 years later. Healthful changes in modifiable risk factors that occur between childhood and adulthood might prevent children from developing elevated sPLA2 levels in adulthood.

Mediterranean diet and platelet-activating factor; a systematic review

Platelet-activating factor (PAF) is a glycerylether lipid and one of the most potent endogenous mediators of inflammation. Through its binding to a well-characterized receptor it initiates a plethora of cellular pro-inflammatory actions participating by this way to the pathology of most chronic diseases, including cardiovascular and renal diseases, CNS decline and cancer. Among the variety of prudent dietary patterns, Mediterranean Diet (MD) is the dietary pattern with the strongest evidence for its ability to prevent the same chronic diseases. In addition, micronutrients and extracts from several components and characteristic food of the MD can favorably modulate PAF's actions and metabolism either directly or indirectly. However, the role of this traditional diet on PAF metabolism and actions has rarely been studied before. This systematic review summarizes, presents and discusses the outcomes of epidemiologic and intervention studies in humans, investigating the relationships between PAF status and MD. Seventeen full-text articles trying to interlink the components of MD and PAF are found and presented. The results are inconsistent due to the variability of the measured indices and methodology followed. However, preliminary results indicate that the characteristic "healthy" components of the MD, especially, cereals, legumes, vegetables, fish and wine can favorably modulate the pro-inflammatory actions of PAF and regulate its metabolism. Larger, well-controlled studies are necessary to elucidate whether the attenuation of PAF actions can mediate the preventive properties of MD against chronic diseases.

Atypical Antipsychotic Administration in Schizophrenic Patients Leads to Elevated Lipoprotein-Associated Phospholipase A2 Levels and Increased Cardiovascular Risk: A Retrospective Cohort Study

The prevalence of cardiovascular disease (CVD) is higher in patients with schizophrenia than in the general population. We aimed to investigate whether atypical antipsychotics (AAP) increase the levels of lipoprotein-associated phospholipase A2 (Lp-PLA2), thereby increasing the risk of CVD. The data were from inpatients aged 18-60 years with a diagnosis of schizophrenia according to ICD-10 at the Affiliated Brain Hospital of Nanjing Medical University who underwent physical examination between 1 October 2014 and 30 September 2016. A retrospective cohort study was used to analyse the correlation between AAP, Lp-PLA2 levels and the CVD risk (it was determined that Lp-PLA2 values >200 ng/mL were defined as high CVD risk) in patients treated with monotherapy, olanzapine, clozapine or quetiapine. Data were collected for 452 patients with eligible schizophrenia: 163 treated with clozapine, 186 treated with olanzapine, 47 treated with quetiapine and 56 receiving no medication. Compared with the no-medication patients, AAP administration in patients with olanzapine, clozapine or quetiapine had higher serum Lp-PLA2 levels when age, sex, BMI and fasting glucose level were matched. AAP were significantly associated with serum Lp-PLA2 level by Spearman's correlation coefficients. The results of logistic regression analysis showed that AAP administration was an independent factor of CVD risk when adjusted by potential confounding factors. This study is the first to confirm that AAP administration, especially clozapine and olanzapine, could increase Lp-PLA2 levels and CVD risk, independent of drug-induced weight gain in schizophrenia. The extent and the factors of increasing Lp-PLA2 level and CVD risk in olanzapine, clozapine and quetiapine are discrepant. The possible effects of AAP on Lp-PLA2 in schizophrenia patients are involved in pro-inflammatory cytokines and hormones.

Replacing carbohydrate with protein and fat in prediabetes or type-2 diabetes: greater effect on metabolites in PBMC than plasma

BACKGROUND

Active metabolism of peripheral blood mononuclear cells (PBMC) could suggest their suitability for metabolomics studies. This study examined whether reductions in PBMCs and plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) activities induced by dietary intervention affected the overall metabolic profiles of PBMC and plasma.

METHODS

Eighty nonobese subjects aged 40-70 years (18.5 ≤ BMI < 30 kg/m(2)) with prediabetes or newly-diagnosed type-2 diabetes were assigned to consume either the usual refined-rice diet (control group, n = 40) or to replace refined rice with whole grains and legumes as carbohydrates (whole-grain group, n = 40) for three meals per day during the 12-week intervention. Fasting PBMC and plasma metabolomes were profiled using UPLC-LTQ-Orbitrap mass spectrometry.

RESULTS

After 12 weeks, changes in fasting glucose, HbA1c, HOMA-IR, MDA, ox-LDL, LDL particle size, plasma Lp-PLA2 activity, and PBMC enzyme activity in the whole-grain group were significantly different from those in the control group before and after adjusting for baseline levels. The PBMC levels of L-leucine, oleamide, lysoPC (16:0), and lysoPC (18:0) in the whole-grain group showed greater reductions compared with those of the control group. Changes in plasma metabolites were not significantly different between the two groups. Changes in PBMC Lp-PLA2 activity positively correlated with changes in L-leucine, oleamide, lysoPC (16:0), lysoPC (18:0), glucose, and ox-LDL, and negatively correlated with changes in LDL particle size.

CONCLUSIONS

This study showed that dietary intervention in prediabetic or type-2 diabetic patients had a greater effect on PBMC Lp-PLA2 activity and metabolites compared with those of plasma metabolites.

TRIAL REGISTRATION

NCT02191644.

Expression of Lipoprotein associated phospholipase A2 enzyme in medical undergraduate students with metabolic syndrome

AIMS

Metabolic syndrome (MS) and atherosclerosis are chronic inflammatory conditions. Lipoprotein-associated phospholipase A2 (LpPLA2) is a circulatory marker of systemic inflammation and a risk predictor for cardiovascular diseases. This study aims to evaluate the expression of this enzyme in an effort to understand the underlying mechanism of atherosclerosis in MS.

METHODS

This study included twenty patients of MS and same number of healthy controls. Anthropometry and clinical examination were carried out in both groups. Real time PCR was performed for LpPLA2 mRNA and relative expression was calculated using ΔΔCT method keeping β2 microglobin and β-actin as internal controls.

RESULTS

LpPLA2 mRNA expression was higher in patients of MS. Fold change was 5.7 when β2 microglobin was used as normaliser and 4.97 when β-actin was used. mRNA levels of LpPLA2 correlated significantly with waist circumference (r=0.462, p=0.003) and systolic blood pressure (r=0.392, p=0.015) as well as high density lipoprotein cholesterol (r=-0.453, p=0.003).

CONCLUSIONS

High expression of LpPLA2 mRNA indicates that systemic inflammation has role in pathogenesis of atherosclerosis in patients of MS. This is evident from its direct correlation with blood pressure. The study also suggests that expression of LpPLA2 may be associated with obesity. Therefore, LpPLA2 mRNA expression levels may develop as an important risk predictor for vascular complications in MS.

Circulating Lp-PLA₂ activity correlates with oxidative stress and cytokines in overweight/obese postmenopausal women not using hormone replacement therapy

Controversy remains regarding whether there is an association between circulating lipoprotein-associated phospholipase A2 (Lp-PLA2), cytokines, and oxidative stress in healthy postmenopausal women. We investigated the influence of age on Lp-PLA2 activity in postmenopausal women not using hormone therapy and the relationship of Lp-PLA2 enzyme activity to serum cytokine levels and oxidative stress indices. Normal weight (n = 1284) and overweight/obese (n = 707) postmenopausal women not using hormone therapy were categorized into five age groups: 50-54, 55-59, 60-64, 65-69, and 70-89 years. Overweight-obese women showed higher plasma Lp-PLA2 activity, urinary 8-epi-prostaglandin F2α (8-epi-PGF2α), serum interleukin (IL)-6, and smaller LDL particles than normal-weight women after adjusting for age, years postmenopause, smoking, drinking, blood pressure, glucose, insulin, lipid profiles, BMI, and waist circumference. Overweight/obese women 70-89 years old showed higher Lp-PLA2 activity than those aged 50-54 years, whereas no significant difference in Lp-PLA2 activity existed across normal-weight female age groups. Overweight/obese women aged ≥ 65 years showed higher Lp-PLA2, oxidized LDL (ox-LDL), IL-6, and 8-epi-PGF2α than age-matched normal-weight controls. Overweight/obese women aged ≥ 70 years had higher ox-LDL levels than those aged 50-59, and overweight/obese women aged 65-89 showed higher IL-6 and 8-epi-PGF2α. There were strong positive correlations between Lp-PLA2 and ox-LDL (r = 0.385, P < 0.001), Lp-PLA2 and IL-6 (r = 0.293, P < 0.001), and ox-LDL and IL-6 (r = 0.303, P < 0.001) in overweight/obese women; however, these relationships were weak in normal-weight women. These results suggest that aging and obesity-related oxidative and inflammatory mediators are associated with Lp-PLA2 activity in overweight/obese postmenopausal women not using hormone therapy.

Unexpected inverse relationship between impaired glucose metabolism and lipoprotein-associated phospholipase A2 activity in patients with stable vascular disease

BACKGROUND

Elevated lipoprotein-associated phospholipase A2 activity (aLp-PLA2) is associated with increased risk of cardiovascular events. In patients with stable atherovascular disease, we aimed to investigate whether impaired glucose metabolism might be associated with higher risk of elevated aLp-PLA2.

METHODS

We conducted a cross-sectional study in 825 stable patients after acute coronary syndrome, coronary revascularization or after first ischemic stroke (Czech part of EUROASPIRE III surveys). We measured aLp-PLA2 using diaDexus commercial kit.

RESULTS

In multiple step-wise regression analysis, the aLp-PLA2 was significantly positively associated with male gender, current smoking, LDL cholesterol and metabolic syndrome and negatively with statin treatment, body mass index and LDL/apoB ratio. After adjustment for these confounders, we observed an inverse relationship between aLp-PLA2 and fasting glycemia [β coefficient -2.18 (p<0.0001)] or glycated hemoglobin A1c (HbA1c) [β coefficient -5.89 (p<0.0001)]. Moreover, we found a positive association between aLp-PLA2 and pancreatic β cell function [β coefficient +0.10 (p<0.0001)], but not with an insulin sensitivity.

CONCLUSION

In present study, we cannot confirm any additive risk of impaired glucose metabolism in terms of increased activity of Lp-PLA2. On the contrary, presence of inadequately controlled diabetes mellitus was independently associated with lower risk of elevated aLp-PLA2 .

Replacing with whole grains and legumes reduces Lp-PLA2 activities in plasma and PBMCs in patients with prediabetes or T2D

To determine dietary effects on circulating lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and enzyme activity in peripheral blood mononuclear cells (PBMCs), 99 patients with impaired fasting glucose, impaired glucose tolerance, or newly-diagnosed T2D were randomly assigned to either a control group (usual diet with refined rice) or the whole grain and legume group. Substitution of whole grains and legumes for refined rice was associated with the replacement of 7% of energy from carbohydrates with energy from protein (about 4%) and fat. After 12 weeks, the whole grain and legume group showed a significant decrease in fasting glucose, insulin, homeostasis model assessment-insulin resistance, hemoglobin A1c, malondialdehyde, plasma Lp-PLA2 activity, and oxidized LDL (ox-LDL), and an increase in LDL particle size. The changes (Δs) in these variables in the whole grain and legume group were significantly different from those in controls after adjustment for the baseline levels. When all subjects were considered, Δ plasma Lp-PLA2 positively correlated with Δ glucose, Δ PBMC Lp-PLA2, Δ ox-LDL, and Δ urinary 8-epi-prostaglandin F2α after being adjusted for confounding factors. The Δ PBMC Lp-PLA2 correlated positively with Δ glucose and Δ ox-LDL, and negatively with Δ LDL particle size and baseline PBMC Lp-PLA2 The substitution of whole grains and legumes for refined rice resulted in a reduction in Lp-PLA2 activities in plasma and PBMCs partly through improved glycemic control, increased consumption of protein relative to carbohydrate, and reduced lipid peroxides.

Effect of tobacco smoking and smoking cessation on plasma lipoproteins and associated major cardiovascular risk factors: a narrative review

Cigarette smoking, active or passive, kills about 6 million people each year worldwide. Cardiovascular disease (CVD) is responsible for 40% of all smoking-related deaths, lung cancer accounts for 20% of all smoking-related deaths, and chronic obstructive pulmonary disease is related to another 20% of deaths. In this narrative review we consider the relationship between cigarette smoking and CVD. We discuss disease states and/or CVD risk factors related to smoking, such as dyslipidaemia, vascular inflammation, endothelial dysfunction, arterial stiffness, insulin resistance, type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and non-alcoholic fatty liver disease (NAFLD) as well as their complex interrelations. Smoking cessation can correct abnormalities related to smoking; however, success rates are relatively low. In cases of inability to quit, measures to minimize the adverse effects of smoking specifically related to CVD should be taken. Smokers should receive best practice treatment, according to guidelines, as for non-smokers.

n-3 and n-6 Fatty acids are independently associated with lipoprotein-associated phospholipase A2 in the Multi-Ethnic Study of Atherosclerosis

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an independent risk factor for CVD and has been proposed as a marker of vascular inflammation. Polyunsaturated n-3 fatty acids (FA) and several n-6 FA are known to suppress inflammation and may influence Lp-PLA2 mass and activity. The associations of n-3 and n-6 plasma FA with Lp-PLA2 mass and activity were analysed using linear regression analysis in 2246 participants of the Multi-Ethnic Study of Atherosclerosis; statistical adjustments were made to control for body mass, inflammation, lipids, diabetes, and additional clinical and demographic factors. Lp-PLA2 mass and activity were significantly lower in participants with the higher n-3 FA EPA (β = - 4·72, P< 0·001; β = - 1·53; P= 0·023) and DHA levels (β = - 4·47, β = - 1·87; both P< 0·001). Those in the highest quintiles of plasma EPA and DHA showed 12·71 and 19·15 ng/ml lower Lp-PLA2 mass and 5·7 and 8·90 nmol/min per ml lower Lp-PLA2 activity than those in the first quintiles, respectively. In addition, lower Lp-PLA2 mass and activity were associated with higher levels of n-6 arachidonic acid (β = - 1·63, β = - 1·30; both P< 0·001), while γ-linolenic acid was negatively associated with activity (β = - 27·7, P= 0·027). Lp-PLA2 mass was significantly higher in participants with greater plasma levels of n-6 linoleic (β = 0·828, P= 0·011) and dihomo-γ-linolenic acids (β = 4·17, P= 0·002). Based on their independent associations with Lp-PLA2 mass and activity, certain n-3 and n-6 FA may have additional influences on CVD risk. Intervention studies are warranted to assess whether these macronutrients may directly influence Lp-PLA2 expression or activity.

Influence of obesity and cardiometabolic makers on lipoprotein-associated phospholipase A2 (Lp-PLA2) activity in adolescents: the healthy young cross-sectional study

BACKGROUND

Lipoprotein-associated phospholipase A2 activity (Lp-PLA2) is a good marker of cardiovascular risk in adults. It is strongly associated with stroke and many others cardiovascular events. Despite this, the impact of obesity on this enzyme activity and its relation to biomarkers of cardiovascular disease in adolescents is not very well investigated. The purpose of this article is to evaluate the influence of obesity and cardiometabolic markers on Lp-PLA2 activity in adolescents.

RESULTS

This cross-sectional study included 242 adolescents (10-19 years) of both gender. These subjects were classified in Healthy Weight (n = 77), Overweight (n = 82) and Obese (n = 83) groups. Lipid profile, glucose, insulin, HDL size, LDL(-) and anti-LDL(-) antibodies were analyzed. The Lp-PLA2 activity was determined by a colorimetric commercial kit. Body mass index (BMI), waist circumference and body composition were monitored. Food intake was evaluated using three 24-hour diet recalls. The Lp-PLA2 activity changed in function to high BMI, waist circumference and fat mass percentage. It was also positively associated with HOMA-IR, glucose, insulin and almost all variables of lipid profile. Furthermore, it was negatively related to Apo AI (β = -0.137; P = 0.038) and strongly positively associated with Apo B (β = 0.293; P < 0.001) and with Apo B/Apo AI ratio (β = 0.343; P < 0.001). The better predictor model for enzyme activity, on multivariate analysis, included Apo B/Apo AI (β = 0.327; P < 0.001), HDL size (β = -0.326; P < 0.001), WC (β = 0.171; P = 0.006) and glucose (β = 0.119; P = 0.038). Logistic regression analysis demonstrated that changes in Apo B/Apo AI ratio were associated with a 73.5 times higher risk to elevated Lp-PLA2 activity.

CONCLUSIONS

Lp-PLA2 changes in function of obesity, and that it shows important associations with markers of cardiovascular risk, in particular with waist circumference, glucose, HDL size and Apo B/Apo AI ratio. These results suggest that Lp-PLA2 activity can be a cardiovascular biomarker in adolescence.

Plasma Lp-PLA(2) mass and apoB-lipoproteins that carry Lp-PLA(2) decrease after sodium

BACKGROUND

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2) ) is a novel cardiovascular risk marker, which is predominantly complexed to apolipoprotein (apo) B-containing lipoproteins in human plasma. As increasing dietary sodium intake may decrease plasma apoB-containing lipoproteins, we tested whether a sodium challenge lowers plasma Lp-PLA(2) mass, as well as the levels of apoB-containing lipoprotein particles carrying Lp-PLA(2) (apoB-Lp-PLA(2) ), employing a newly developed enzyme-linked immunosorbent assay.

MATERIALS AND METHODS

In 45 women and 31 men (mean age 44 ± 14 years), plasma Lp-PLA(2) mass (turbidimetric immunoassay), the level of apoB-Lp-PLA(2) , expressed in apoB concentration and lipoproteins were measured in response to a 3-day challenge with 9 g sodium chloride tablets daily.

RESULTS

Urinary sodium excretion increased from 165 ± 60 to 321 ± 70 mmol/24 h (P<0.001) after salt loading. Plasma Lp-PLA(2) mass decreased from 618 (493-719) to 588 (465-698) μg/L (P<0.001), and apoB-Lp-PLA(2) decreased from 0.276 (0.200-0.351) to 0.256 (0.189-0.328) g LDL protein/L (P=0.004) in response to the sodium challenge together with decreases in plasma total cholesterol, nonhigh-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein B and the total cholesterol/HDL cholesterol ratio (P<0.01 for all). Changes in plasma Lp-PLA(2) mass were correlated positively with changes in total cholesterol, LDL cholesterol and non-HDL cholesterol (r=0.260-0.276, P<0.05 to P<0.02), whereas changes in apoB-Lp-PLA(2) were correlated positively with changes in non-HDL cholesterol and in the total cholesterol/HDL cholesterol ratio (r=0.232-0.385, P<0.05-0.01).

CONCLUSION

Both plasma Lp-PLA(2) mass levels and apoB-Lp-PLA(2) decrease in response to a short-term oral sodium challenge.

LDL subclasses and lipoprotein-phospholipase A2 activity in suppressed HIV-infected patients switching to raltegravir: Spiral substudy

OBJECTIVE

To analyze the effect of switching the ritonavir-boosted protease inhibitor (PI/r) in a stable combined antiretroviral therapy (cART) regimen to raltegravir on low-density lipoprotein (LDL) particles, and lipoprotein-associated phospholipase A2 (Lp-PLA2).

DESIGN

Substudy of a multicenter randomized trial that compared the efficacy of switching a PI/r to raltegravir-based cART in stable HIV-infected patients.

METHODS

LDL size and phenotype (by gel-gradient electrophoresis), Lp-PLA2 (by 2-thio-PAF [Cayman]), proprotein convertase subtilisin/kexin type 9 (PCSK9) (by ELISA), and standard lipid parameters were measured at baseline and week 48.

RESULTS

Eighty-one (PI/r n = 41 and raltegravir n = 40) patients were evaluated. No differences in baseline demographic and metabolic variables between arms were found except in apolipoprotein (Apo) B (p = 0.042). At week 48, total cholesterol (TC) (p < 0.001), LDL-c (p = 0.023), non-high density lipoprotein cholesterol non-high-density lipoprotein cholesterol (non-HDL-c) (p < 0.001), TC/HDL (p = 0.026), triglyceride (p < 0.001), Apo B (p < 0.001), Apo A-I (p = 0.004) and Lp (a) (p = 0.005) decreased in raltegravir arm compared to PI/r arm. At week 48, a shift from LDL phenotype B to the less atherogenic phenotype A was observed only in raltegravir arm (p < 0.001). LDL size increased (PI/r 2.1 nm, p = 0.019; raltegravir 3.8 nm, p = 0.001) and cholesterol content in small and dense LDL subfractions (LDL 4,5,6) decreased (PI/r p = 0.007, raltegravir p = 0.006) at week 48 in both arms. Total Lp-PLA2 activity (PI/r p = 0.037 and raltegravir p = 0.051) and PCSK9 plasma concentration decreased in both arms (PI/r p = 0.034 and raltegravir p < 0.001).

CONCLUSIONS

Switching a PI/r to a raltegravir-based cART in virologically suppressed HIV-infected patients was associated with an overall improvement in lipid profile, including a shift to a less atherogenic LDL phenotype.

Effects of ethanol intake on lipoproteins

These review discusses the effects of ethanol on lipoprotein levels and function as related to atherosclerosis and cardiovascular disease (CVD), with special emphasis on recent publications. Ethanol's effects on high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and other CVD risk factors recently have been explored. Other new data address genetic and demographic predictors and mechanisms of these responses. Not surprisingly, the results of some recent studies corroborate, whereas others differ from, earlier seemingly well-established findings. Prior and recent evidence shows favorable changes in HDL, other CVD risk factors, and CVD event rates with moderate, regular ethanol intake, and recent publications have explored the mechanisms of this relationship. Application of these findings in clinical practice remains problematic, however, due to the lack of randomized, controlled clinical trials of ethanol and due to the potential hazards of ethanol consumption.

Normal levels of inflammatory markers in treated patients with familial hypercholesterolaemia: a cross-sectional study

OBJECTIVE

To assess the relationship of levels of inflammatory risk markers to presence of clinical coronary artery disease (CAD) in patients with treated heterozygous familial hypercholesterolaemia.

DESIGN

A cross-sectional study of patients on the Simon Broome Familial Hyperlipidaemia Register.

SETTING

Six hospital outpatient clinics in the UK.

PARTICIPANTS

A total of 211 men and 199 women with heterozygous familial hypercholesterolaemia.

MAIN OUTCOME MEASURES

Analysis of conventional risk factors and concentrations of high-sensitivity C-reactive protein (hsCRP), lipoprotein(a), serum intercellular adhesion molecule (sICAM), interleukin-6 (IL-6) and lipoprotein-associated phospholipase A2 (LpPLA2) mass.

RESULTS

CAD was present in 104 men and in 55 women; the mean ages of onset were 43.1 and 46.5 years, respectively. On univariate analysis there was a positive relationship of CAD with age, male sex, smoking, IL-6 and sICAM, and an inverse relationship with low-density lipoprotein (LDL) and LpPLA2. On multivariate analysis, age, smoking, low LDL and low LpPLA2 were associated with CAD. When LpPLA2 values were adjusted for apoB and aspirin usage, there was no significant difference between those with and without CAD. Only age and smoking were independently associated with CAD in men, and IL-6 and lipoprotein(a) in women.

CONCLUSIONS

Although on univariate analysis inflammatory marker levels were associated with CAD in these patients, the majority of the associations, including that for hsCRP, disappeared when corrected for smoking and apoB. This may be because atherosclerotic plaques in these statin-treated patients were quiescent or an effect of aspirin usage. In this observational study newer risk markers were not usefully associated with the presence or absence of symptomatic CAD.

Variation of lipoprotein associated phospholipase A2 across demographic characteristics and cardiovascular risk factors: a systematic review of the literature

BACKGROUND

Lipoprotein association phospholipase A2 (Lp-PLA(2)), an enzyme which has been found in atherosclerotic plaque is currently under investigation in large Phase III clinical trials of vascular disease prevention. We assessed in a variety of different population settings variation of Lp-PLA(2) mass and activity across gender, ethnicity, diabetes, kidney disease and metabolic syndrome. We also assessed correlations with measures of circulating lipids, systemic inflammation and adiposity.

METHODS

Systematic review of studies measuring Lp-PLA(2) and at least one of the relevant characteristics in >50 participants.

RESULTS

We identified a total of 77 studies involving 102,499 participants meeting the inclusion criteria. Lp-PLA(2) mass and activity were consistently approximately 10% higher in males than females and 15% higher in Caucasians than African Americans or Hispanics. There were no clear associations of Lp-PLA(2) mass or activity with type II diabetes, markers of systemic inflammation (C-reactive protein, fibrinogen) or with body mass index. Correlations of Lp-PLA(2) mass or activity with low density lipoprotein cholesterol and apolipoprotein B were moderate and positive, whilst correlations with high density lipoprotein cholesterol were negative and moderate to weak. There was no clear differences in associations with any of the above characteristics in groups defined based upon prevalent cardiovascular disease or its risk factors.

CONCLUSIONS

Despite considerable variability in absolute levels of Lp-PLA(2) across studies, the variability of Lp-PLA(2) across gender, ethnicity, and levels of circulating lipids and markers of systemic inflammation are more consistent and appear not to vary importantly across categories defined by CVD or its risk factors.

Lipoprotein-associated phospholipase A2 (Lp-PLA2): a review of its role and significance as a cardiovascular biomarker

OBJECTIVE

To conduct a comprehensive, systematic review of studies assessing the significance of lipoprotein-associated phospholipase A2 in cardiovascular diseases (CVDs).

MATERIAL AND METHODS

A review of the literature was performed using the search term "Lipoprotein-associated phospholipase A2 (Lp-PLA2)" and each of the following terms: "cardiovascular risk," "cardiovascular death," "atherosclerotic disease," "coronary events," "transient ischemic attack (TIA)," "stroke," and "heart failure." The searches were performed on Medline, Google Scholar and ClinicalTrials.gov.

RESULTS

The majority of published studies showed a significant association between Lp-PLA2 levels and cardiovascular events after multivariate adjustment. The association was consistent across a wide variety of subjects of both sexes and different ethnic backgrounds.

CONCLUSIONS

The role of Lp-PLA2 as a significant biomarker of vascular inflammation was confirmed, and Lp-PLA2 seems to be closely correlated to cardiovascular events. It may be an important therapeutic target and may have an important role in prevention, risk stratification and personalised medicine.

Circulating and PBMC Lp-PLA2 associate differently with oxidative stress and subclinical inflammation in nonobese women (menopausal status)

BACKGROUND

This study aimed to determine the association of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activity in circulation and peripheral blood mononuclear cells (PBMCs) with inflammatory and oxidative stress markers in nonobese women and according to menopausal status. Lp-PLA(2) activity, a marker for cardiovascular risk is associated with inflammation and oxidative stress.

METHODOLOGY/PRINCIPAL FINDINGS

Eighty postmenopausal women (53.0±4.05 yr) and 96 premenopausal women (39.7±9.25 yr) participated in this study. Lp-PLA(2) activities, interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β in plasma as well as in PBMCs were measured. Plasma ox-LDL was also measured. Postmenopausal women demonstrated higher circulating levels of ox-LDL and IL-6, as well as IL-6, TNF-α, and IL-1β in PBMCs, than premenopausal women. In both groups, plasma Lp-PLA(2) activity positively correlated with Lp-PLA(2) activity in PBMCs and plasma ox-LDL. In premenopausal women, Lp-PLA(2) activities in plasma and PBMCs positively correlated with IL-6, TNF-α, and IL-1β in PBMCs. In postmenopausal women, plasma ox-LDL positively correlated with PBMC cytokine production. In subgroup analysis of postmenopausal women according to plasma ox-LDL level (median level: 48.715 U/L), a significant increase in Lp-PLA(2) activity in the plasma but not the PBMCs was found in the high ox-LDL subgroup. Plasma Lp-PLA(2) activity positively correlated with unstimulated PBMC Lp-PLA(2) activity in the low ox-LDL subgroup (r = 0.627, P<0.001), whereas in the high ox-LDL circulating Lp-PLA(2) activity positively correlated with plasma ox-LDL (r = 0.390, P = 0.014) but not with Lp-PLA(2) activity in PBMCs.

CONCLUSIONS/SIGNIFICANCE

The lack of relation between circulating Lp-PLA(2) activity and Lp-PLA(2) activity in PBMCs was found in postmenopausal women with high ox-LDL. This may indicate other sources of circulating Lp-PLA(2) activity except PBMC in postmenopausal women with high ox-LDL. We also demonstrated that circulating Lp-PLA(2) and PBMC secreted Lp-PLA(2) associate differently with markers of oxidative stress and sub clinical inflammation in nonobese women, particularly according to the menopausal states.

Food patterns, inflammation markers and incidence of cardiovascular disease: the Malmö Diet and Cancer study

OBJECTIVES

To examine the associations between food patterns constructed using cluster analysis and markers of systemic and vascular inflammation, and incident cardiovascular disease (CVD) after 13 years of follow-up.

DESIGN

Population-based, prospective cohort study.

SETTING AND SUBJECTS

Cluster analysis identified six food patterns from 43 food group variables among 4999 subjects, aged 45-68 years, who participated in the Malmö Diet and Cancer cardiovascular programme between 1991 and 1994. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2) ), C-reactive protein concentration and white blood cell (WBC) count were measured using blood samples at baseline. Incidence of CVD (coronary events and ischaemic stroke) was monitored over 13 years of follow-up.

RESULTS

The fibre-rich bread pattern was associated with favourable effects on WBC count in women, and the low-fat and high-fibre pattern with favourable effects on Lp-PLA(2) mass in women, and on Lp-PLA(2) activity in men. However, the milk fat and sweets and cakes patterns were both associated with adverse effects; the former on WBC count in women and on Lp-PLA(2) mass in men, and the latter on WBC count and Lp-PLA(2) mass in women. The milk fat and sweets and cakes patterns were associated with increased CVD risk in women.

CONCLUSIONS

The results of this study support the present Nordic dietary recommendations indicating that diets rich in high-fibre, low-fat and low-sugar foods are favourably associated with markers of inflammation and, potentially, with CVD risk.

Antioxidant and inflammatory aspects of lipoprotein-associated phospholipase A₂ (Lp-PLA₂): a review

The association of cardiovascular events with Lp-PLA₂ has been studied continuously today. The enzyme has been strongly associated with several cardiovascular risk markers and events. Its discovery was directly related to the hydrolysis of the platelet-activating factor and oxidized phospholipids, which are considered protective functions. However, the hydrolysis of bioactive lipids generates lysophospholipids, compounds that have a pro-inflammatory function. Therefore, the evaluation of the distribution of Lp-PLA₂ in the lipid fractions emphasized the dual role of the enzyme in the inflammatory process, since the HDL-Lp-PLA₂ enzyme contributes to the reduction of atherosclerosis, while LDL-Lp-PLA₂ stimulates this process. Recently, it has been verified that diet components and drugs can influence the enzyme activity and concentration. Thus, the effects of these treatments on Lp-PLA₂ may represent a new kind of prevention of cardiovascular disease. Therefore, the association of the enzyme with the traditional assessment of cardiovascular risk may help to predict more accurately these diseases.

Lipoprotein associated phospholipase A(2): role in atherosclerosis and utility as a biomarker for cardiovascular risk

Atherosclerosis and its clinical manifestations are widely prevalent throughout the world. Atherogenesis is highly complex and modulated by numerous genetic and environmental risk factors. A large body of basic scientific and clinical research supports the conclusion that inflammation plays a significant role in atherogenesis along the entire continuum of its progression. Inflammation adversely impacts intravascular lipid handling and metabolism, resulting in the development of macrophage foam cell, fatty streak, and atheromatous plaque formation. Given the enormous human and economic cost of myocardial infarction, ischemic stroke, peripheral arterial disease and amputation, and premature death and disability, considerable effort is being committed to refining our ability to correctly identify patients at heightened risk for atherosclerotic vascular disease and acute cardiovascular events so that they can be treated earlier and more aggressively. Serum markers of inflammation have emerged as an important component of risk factor burden. Lipoprotein-associated phospholipase A2 (Lp-PLA(2)) potentiates intravascular inflammation and atherosclerosis. A variety of epidemiologic studies support the utility of Lp-PLA(2) measurements for estimating and further refining cardiovascular disease risk. Drug therapies to inhibit Lp-PLA(2) are in development and show considerable promise, including darapladib, a specific molecular inhibitor of the enzyme. In addition to substantially inhibiting Lp-PLA(2) activity, darapladib reduces progression of the necrotic core volume of human coronary artery atheromatous plaque. The growing body of evidence points to an important role and utility for Lp-PLA(2) testing in preventive and personalized clinical medicine.

Effects of ethanol intake on lipoproteins and atherosclerosis

PURPOSE OF REVIEW

This article reviews published studies regarding effects of ethanol intake on lipoprotein levels and function as they relate to atherosclerosis, with special emphasis on recent publications in the past 2 years.

RECENT FINDINGS

Some recent studies have explored novel mechanisms of ethanol on atherogenesis via effects on HDL composition and function. Other studies have focused on changes in levels of LDL cholesterol (LDL-C), triglyceride, and other factors such as inflammatory markers C-reactive protein (CRP) and lipoprotein-associated phospholipase A2 (LpPLA2). Other areas of emphasis have been the effects within specific populations and between genders, as well as contributions of genetic polymorphisms in prediction of response to ethanol. Surprisingly, results of recent studies are often at odds with prior, seemingly well established findings.

SUMMARY

The association between moderate ethanol consumption and favorable changes in lipoproteins and lipoprotein-related factors in atherosclerosis continues to become better established with the publication of new studies in this field. Continued progress is being achieved in understanding the well established link between moderate intake and reduced risk of cardiovascular disease (CVD). Nevertheless, it remains difficult to implement these findings in clinical practice due to the ongoing lack of randomized, blinded clinical trial data, and the well known hazards of excess ethanol consumption.