Lp-PLA2 Activity Research Articles

Effect of Statin Treatment on Lipoprotein-Associated Phospholipase A2 Mass and Activity: A Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials.

The goal of this meta-analysis was to establish whether statin treatment reduces Lp-PLA2 mass concentration and/or activity. PubMed, Scopus, Web of Science, ClinicalTrials.gov, and Google Scholar databases were searched using MESH terms and keywords. Randomized controlled trials (RCT) with either parallel or cross-over design examining the effect of statins on Lp-PLA2 mass and/or activity were included in meta-analysis. Out of 256 articles, 10 RCT were selected for meta-analysis. Statin therapy significantly reduced both Lp-PLA2 mass (WMD -44.46 ng/mL; 95%CI -59.01, -29.90; p < 0.001; I2 = 93%) and activity (WMD -39.37 nmol/min/mL; 95%CI -69.99, -8.75; p = 0.01; I2 = 100%). The sensitivity analysis was robust for Lp-PLA2 mass and was also positive for two studies concerning Lp-PLA2 activity. Statin therapy significantly reduced both Lp-PLA2 mass and activity.

Associations of phase angle with platelet-activating factor metabolism and related dietary factors in healthy volunteers.

Phase angle (PA) is derived from bioelectrical impedance analysis (BIA). It reflects cell membrane function and decreases in disease. It is affected by inflammation, oxidative stress, and diet. Platelet-activating factor (PAF) is a potent inflammatory lipid mediator. Its levels, along with the activity of its metabolic enzymes, including CDP-choline:1-alkyl-2-acetyl-sn-glycerol-cholinephosphotransferase, acetyl-CoA:lyso-PAF-acetyltransferases, and PAF-AH/Lp-PLA2 are also related to dietary factors, such as the dietary antioxidant capacity (DAC). The aim of the study was to estimate whether the PAF metabolic circuit and related dietary factors are associated with PA in healthy volunteers. In healthy subjects, PAF, its metabolic enzyme activity, and erythrocyte fatty acids were measured, while desaturases were estimated. Food-frequency questionnaires and recalls were used, and food groups, macronutrient intake, MedDietScore, and DAC were assessed. Lifestyle and biochemical variables were collected. DXA and BIA measurements were performed. Lp-PLA2 activity was positively associated with PA (rho = 0.651, p < 0.001, total population; rho = 0.780, p < 0.001, women), while PAF levels were negatively associated with PA only in men (partial rho = -0.627, p = 0.012) and inversely related to DAC. Estimated desaturase 6 was inversely associated with PA (rho = -0.404, p = 0.01, total sample). Moreover, the DAC correlated positively with PA (rho = 0.513, p = 0.03, women). All correlations were adjusted for age, body mass index, and sex (if applicable). PA is associated with PAF levels and Lp-PLA2 activity in a gender-dependent fashion, indicating the involvement of PAF in cell membrane impairment. The relationship of PA with DAC suggests a protective effect of antioxidants on cellular health, considering that antioxidants may inhibit PAF generation.

Lipoprotein associated- phospholipase A2 in STEMI vs. NSTE-ACS patients: a marker of cardiovascular atherosclerotic risk rather than thrombosis.

A consecutive cohort of patients undergoing coronary angiography for acute coronary syndrome (ACS) were included and divided according to presentation for non ST-segment elevation-ACS or ST-segment elevation Myocardial Infarction (STEMI). Lp-PLA2 activity was assessed in blood samples drawn at admission using the Diazyme Lp-PlA2 Activity Assay. We included in our study 117 patients, of whom 31 (26.5%) presented with STEMI. STEMI patients were significantly younger (p = 0.05), displayed a lower rate of hypertension (p = 0.002), previous MI (p = 0.001) and PCI (p = 0.01) and used less frequently statins (p = 0.01) and clopidogrel (p = 0.02). White blood cells and admission glycemia were increased in STEMI (p = 0.001, respectively). The prevalence and severity of CAD was not different according to ACS types, but for a higher prevalence of thrombus (p < 0.001) and lower TIMI flow (p = 0.002) in STEMI. The levels of Lp-PlA2 were significantly lower in STEMI as compared to NSTE-ACS patients, (132 ± 41.1 vs. 154.6 ± 40.9 nmol/min/mL, p = 0.01). In fact, the rate of patients with Lp-PlA2 above the median (148 nmol/min/mL) was significantly lower in STEMI patients as compared to NSTE-ACS (32.3% vs. 57%, p = 0.02, adjusted OR[95% CI] = 0.20[0.06-0.68], p = 0.010). Moreover, a direct linear relationship was observed between Lp-PlA2 and LDL-C (r = 0.47, p < 0.001), but not with inflammatory biomarkers. The present study shows that among ACS patients, the levels of Lp-PlA2 are inversely associated with STEMI presentation and thrombotic coronary occlusion, being instead increased in NSTE-ACS patients, therefore potentially representing a marker of more aggressive chronic cardiovascular disease with an increased risk of recurrent cardiovascular events.

101 LIPOPROTEIN ASSOCIATED PHOSPHOLIPASE A2 IN STEMI VS NSTE-ACS PATIENTS: A MARKER OF CARDIOVASCULAR ATHEROSCLEROTIC RISK RATHER THAN THROMBOSIS

Abstract Background The precise role of Lipoprotein associated phospholipase A2 (Lp-PlA2) in the pathogenesis of acute coronary syndromes (ACS) and in the prediction of future cardiovascular events is still debated. So far, few data exist on the variations of Lp-PlA2 activity in ACS and especially in NSTE-ACS vs STEMI patients, where thrombotic and atherosclerotic mechanisms could play a differential role. The aim of the present study was, then, to compare Lp-PlA2 activity according to the type of ACS presentation. Methods A consecutive cohort of patients undergoing coronary angiography for acute coronary syndrome (ACS) were included and divided according to presentation for non ST-segment elevation-ACS or ST-segment elevation Myocardial Infarction (STEMI). Lp-PLA2 activity was assessed on blood samples drawn at admission using the Diazyme Lp-PlA2 Activity Assay. Results We included in our study 117 patients, of whom 31 (26.5%) presented with STEMI. STEMI patients were significantly younger (p=0.05), displayed a lower rate of hypertension (p=0.002), previous MI (p=0.001) and PCI (p=0.01) and used less frequently statins (p=0.01) and clopidogrel (p=0.02). White blood cells and admission glycemia were increased in STEMI (p=0.001, respectively). The prevalence and severity of CAD was not different according to ACS types, but for a higher prevalence of thrombus (p&amp;lt;0.001) and lower TIMI flow (p=0.002) in STEMI. The levels of Lp-PlA2 were significantly lower in STEMI as compared to NSTE-ACS patients, (132±41.1 vs 154.6 ±40.9 nmol/min/mL, p=0.01). In fact, the rate of patients with Lp-PlA2 above the median (148 nmol/min/mL) was significantly lower in STEMI patients as compared to NSTE-ACS (32.3% vs 57%, p=0.02, adjusted OR[95% CI]=0.20[0.06-0.68], p=0.010). Moreover, a direct linear relationship was observed between Lp-PlA2 and LDL-C (r=0.47, p&amp;lt;0.001), but not with inflammatory biomarkers. Conclusion The present study shows that among ACS patients, the levels of Lp-PlA2 are inversely associated with STEMI presentation and thrombotic coronary occlusion, being instead increased in NSTE-ACS patients, and with recurrent cardiovascular events, therefore potentially representing a marker of a more aggressive atherosclerotic disease and higher cardiovascular burden and risk.

Causal effect of Lipoprotein-associated phospholipase A2 activity on coronary artery disease and myocardial Infarction: A Two-Sample Mendelian Randomization study

BackgroundLipoprotein-associated phospholipase A2 (Lp-PLA2) activity has been reported to be associated with coronary artery disease (CAD) and myocardial infarction (MI). However, whether Lp-PLA2 is a causal risk factor for CAD and MI remains unclear. Herein, we performed a two-sample mendelian randomization (MR) study to assess the causal effect of Lp-PLA2 activity on CAD and MI. MethodsWe selected 7 single-nucleotide polymorphisms (SNPs) associated with Lp-PLA2 activity as instrumental variables based on the data from Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium with 13,664 European individuals. Summary data about CAD and MI were obtained from Coronary Artery Disease Genome-wide Replication and Meta-analysis plus the Coronary Artery Disease Genetics (CARDIOGRAMPLUSC4D) consortium with 60,801 CAD cases and 43,676 MI cases (mostly European). The inverse-variance weighted method was applied to assess the causal associations of Lp-PLA2 activity with CAD and MI in the main analysis. ResultsThe main inverse-variance weighted (IVW) MR analysis showed that 1-SD increment in genetically determined LP-PLA2 activity was associated with increased risks of CAD (odds ratio, 5.93; 95% CI, 2.91–12.07; p value = 9.43 × 10-7) and MI (odds ratio, 4.71; 95% CI, 2.49–8.90; p value = 1.86 × 10-6). MR-Egger regression showed no evidence of pleiotropic bias. The causal associations were consistent in sensitivity analyses with multiple MR methods, in which showed Lp-PLA2 activity was causally associated with an increased risk of CAD and MI. ConclusionsIn this two-sample MR study, high Lp-PLA2 activity was a causal risk factor for CAD and MI, indicating that Lp-PLA2 activity may be a promising intervention target in reducing the risk of CAD and MI.

Diabetes status modifies the long-term effect of lipoprotein-associated phospholipase A2 on major coronary events

Aims/hypothesisLipoprotein-associated phospholipase A2 (Lp-PLA2) activity has an independent prognostic association with major coronary events (MCE). However, no study has investigated whether type 2 diabetes status modifies the effect of Lp-PLA2 activity or inhibition on the risk of MCE. We investigate the interaction between diabetes status and Lp-PLA2 activity with risk of MCE. Subsequently, we test the resulting hypothesis that diabetes status will play a role in modifying the efficacy of an Lp-PLA2 inhibitor.MethodsA retrospective cohort study design was utilised in two study populations. Discovery analyses were performed in the Genetics of Diabetes Audit and Research in Tayside Scotland (GoDARTS) cohort based in Scotland, UK. Participants were categorised by type 2 diabetes control status: poorly controlled (HbA1c ≥ 48 mmol/mol or ≥6.5%) and well-controlled (HbA1c < 48 mmol/mol or <6.5%) diabetes (n = 7420). In a secondary analysis of the Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy (STABILITY) trial of Lp-PLA2 inhibitor (darapladib) efficacy, 15,828 participants were stratified post hoc by type 2 diabetes diagnosis status (diabetes or no diabetes) at time of recruitment. Lp-PLA2 activity was then divided into population-specific quartiles. MCE were determined from linked medical records in GoDARTS and trial records in STABILITY. First, the interaction between diabetes control status and Lp-PLA2 activity on the outcome of MCE was explored in GoDARTS. The effect was replicated in the placebo arm of STABILITY. The effect of Lp-PLA2 on MCE was then examined in models stratified by diabetes status. This helped determine participants at higher risk. Finally, the effect of Lp-PLA2 inhibition was assessed in STABILITY in the higher risk group. Cox proportional hazards models adjusted for confounders were used to assess associations.ResultsIn GoDARTS, a significant interaction between increased Lp-PLA2 activity (continuous and quartile divided) and diabetes control status was observed in the prediction of MCE (p < 0.0001). These effects were replicated in the placebo arm of STABILITY (p < 0.0001). In GoDARTS, stratified analyses showed that, among individuals with poorly controlled diabetes, the hazards of MCE for those with high (Q4) Lp-PLA2 activity was 1.19 compared with individuals with lower (Q1–3) Lp-PLA2 activity (95% CI 1.11, 1.38; p < 0.0001) and 1.35 (95% CI 1.16, 1.57; p < 0.0001) when compared with those with the lowest activity (Q1). Those in the higher risk group were identified as individuals with the highest Lp-PLA2 activity (Q4) and poorly controlled diabetes or diabetes. Based on these observations in untreated populations, we hypothesised that the Lp-PLA2 inhibitor would have more benefit in this higher risk group. In this risk group, Lp-PLA2 inhibitor use was associated with a 33% reduction in MCE compared with placebo (HR 0.67 [95% CI 0.50, 0.90]; p = 0.008). In contrast, Lp-PLA2 inhibitor showed no efficacy in individuals with low activity, regardless of diabetes status, or among those with no baseline diabetes and high Lp-PLA2 activity.Conclusions/interpretationThese results support the hypothesis that diabetes status modifies the association between Lp-PLA2 activity and MCE. These results suggest that cardiovascular morbidity and mortality associated with Lp-PLA2 activity is especially important in patients with type 2 diabetes, particularly those with worse glycaemic control. Further investigation of the effects of Lp-PLA2 inhibition in diabetes appears warranted.Data availabilitySTABILITY trial data are available from clinicaltrials.gov repository through the GlaxoSmithKline clinical study register https://clinicaltrials.gov/ct2/show/NCT00799903. GoDARTS datasets generated during and/or analysed during the current study are available following request to the GoDARTS Access Managements Group https://godarts.org/scientific-community/.Graphical abstract

Consumption of Enriched Yogurt with PAF Inhibitors from Olive Pomace Affects the Major Enzymes of PAF Metabolism: A Randomized, Double Blind, Three Arm Trial

Platelet-activating factor (PAF), a proinflammatory lipid mediator, plays a crucial role in the formation of the atherosclerotic plaque. Therefore, the inhibition of endothelium inflammation by nutraceuticals, such as PAF inhibitors, is a promising alternative for preventing cardiovascular diseases. The aim of the present study was to evaluate the impact of a new functional yogurt enriched with PAF inhibitors of natural origin from olive oil by-products on PAF metabolism. Ninety-two apparently healthy, but mainly overweight volunteers (35–65 years) were randomly allocated into three groups by block-randomization. The activities of PAF’s biosynthetic and catabolic enzymes were measured, specifically two isoforms of acetyl-CoA:lyso-PAF acetyltransferase (LPCATs), cytidine 5′-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT) and two isoforms of platelet activating factor acetylhydrolase in leucocytes (PAF-AH) and plasma (lipoprotein associated phospholipase-A2, LpPLA2). The intake of the enriched yogurt resulted in reduced PAF-CPT and LpPLA2 activities. No difference was observed in the activities of the two isoforms of lyso PAF-AT. In conclusion, intake of yogurt enriched in PAF inhibitors could favorably modulate PAF biosynthetic and catabolic pathways.

Circulating biomarkers of immunity and inflammation, risk of Alzheimer\u2019s disease, and hippocampal volume: a Mendelian randomization study

The aim of this study was to explore the association between genetically predicted circulating levels of immunity and inflammation, and the risk of Alzheimer’s disease (AD) and hippocampal volume, by conducting a two-sample Mendelian Randomization Study. We identified 12 markers of immune cells and derived ratios (platelet count, eosinophil count, neutrophil count, basophil count, monocyte count, lymphocyte count, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, CD4 count, CD8 count, CD4-to-CD8 ratio, and CD56) and 5 signaling molecules (IL-6, fibrinogen, CRP, and Lp-PLA2 activity and mass) as primary exposures of interest. Other genetically available immune biomarkers with a weaker a priori link to AD were considered secondary exposures. Associations with AD were evaluated in The International Genomics of Alzheimer’s Project (IGAP) GWAS dataset (21,982 cases; 41,944 controls of European ancestry). For hippocampal volume, we extracted data from a GWAS meta-analysis on 33,536 participants of European ancestry. None of the primary or secondary exposures showed statistically significant associations with AD or with hippocampal volume following P-value correction for multiple comparisons using false discovery rate < 5% (Q-value < 0.05). CD4 count showed the strongest suggestive association with AD (odds ratio 1.32, P < 0.01, Q > 0.05). There was evidence for heterogeneity in the MR inverse variance-weighted meta-analyses as measured by Cochran Q, and weighted median and weighted mode for multiple exposures. Further cluster analyses did not reveal clusters of variants that could influence the risk factor in distinct ways. This study suggests that genetically predicted circulating biomarkers of immunity and inflammation are not associated with AD risk or hippocampal volume. Future studies should assess competing risk, explore in more depth the role of adaptive immunity in AD, in particular T cells and the CD4 subtype, and confirm these findings in other ethnicities.

Application Value of Lipoprotein-Associated Phospholipase A2 Expression Level in Evaluating the Risk of Major Bleeding in Gestational Diabetes

Studies have shown that obesity and lipid metabolism disorders can lead to increased Lp-PLA2 ac-tivity in the body. However, few studies have reported the correlation between Lp-PLA2 and postpartum hemorrhage in pregnant women with GMD. Clinical data was collected from 43 pregnant women with gestational diabetes combined with postpartum hemorrhage and 50 pregnant women with postpartum diabetes without postpartum bleeding during the same period. Lp-PLA2 expression levels in the serum of pregnant women in both groups were detected. The predictive value of Lp-PLA2 expression level for postpartum hemorrhage was clarified. (1) From 20w to 32w pregnancy, the serum Lp-PLA2 levels of pregnant women in both groups showed a gradual increasing trend. (2) The serum Lp-PLA2 level of the pregnant women in the research group was significantly higher (p < 0.001). (3) Binary logistic regression analysis shows that Lp-PLA2 level has a good correlation with postpartum major bleeding. (4) Comparing of Lp-PLA2 levels in different gestational weeks with respect to its efficacy for predicting postpartum hemorrhage found that the sensitivity and specificity of 24w Lp-PLA2 levels are higher than other gestational weeks, and the area under the 24w parameter curve (0.955) > 32w area under the parameter curve (0.952) > area under the 20w parameter curve (0.940) > area under the 28w parameter curve (0.887). (5) The birth weight of the newborn in the research group was significantly heavier (p < 0.001). Dynamic monitoring of the expression level of Lp-PLA2 in the serum of pregnant women can predict the risk of postpartum hemorrhage in pregnant women at an early stage and help optimize the rescue plan for postpartum hemorrhage.

Lipoprotein-associated phospholipase A2 activity, genetics and calcific aortic valve stenosis in humans

BackgroundLipoprotein-associated phospholipase A2 (Lp-PLA2) activity has been shown to predict calcific aortic valve stenosis (CAVS) outcomes. Our objective was to test the association between plasma Lp-PLA2 activity and genetically elevated...

Elevated Lipoprotein-Associated Phospholipase A2 Independently Affects Age-Related Increases in Systolic Blood Pressure: A Nested Case-Control Study in a Prospective Korean Cohort.

Inflammatory markers are susceptible to changes over time. Thus, we observed changes in inflammatory markers correlating with age-related increases in blood pressure (BP) through a prospective study. The aim of this study was to investigate changes in inflammatory markers that correlate with age-related increases in BP. The study included 1,500 nondiabetic and normotensive healthy subjects at baseline. Of these, 121 individuals who developed hypertension (defined as systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) after 2 years formed the hypertension group. For each incident hypertension case, 2 age- and sex-matched control subjects were selected among those who did not develop hypertension (control group, n = 242). After baseline adjustment, the hypertension group exhibited greater increases in body mass index (BMI), systolic and diastolic BP, triglyceride, total cholesterol, glucose, Lp-PLA2 activity, and urinary 8-epi-prostaglandin F2α (8-epi-PGF2α) levels compared to the control group. In the hypertension group, changes in (Δ) systolic BP correlated positively with Δ Lp-PLA2 activity, which correlated positively with Δ low-density lipoprotein (LDL−) cholesterol and Δ urinary 8-epi-PGF2α levels. Moreover, multiple linear regression revealed baseline systolic BP and Δ Lp-PLA2 activity to be independent predictors of Δ systolic BP in the hypertension group. Our results suggest that age-related increases in systolic BP may correlate strongly with elevated Lp-PLA2 activity and that Lp-PLA2 can be considered a biomarker for systolic BP elevation.

Effects of Extended-Release Niacin on Quartile Lp-PLA2 Levels and Clinical Outcomes in Statin-treated Patients with Established Cardiovascular Disease and Low Baseline Levels of HDL-Cholesterol: Post Hoc Analysis of the AIM HIGH Trial.

Lipoprotein-associated phospholipase A2 (LpPLA2) is an inflammatory marker that has been associated with the presence of vulnerable plaque and increased risk of cardiovascular (CV) events. To assess the effect of extended-release niacin (ERN) on Lp-PLA2 activity and clinical outcomes. We performed a post hoc analysis in 3196 AIM-HIGH patients with established CV disease and low baseline levels of high-density lipoprotein cholesterol (HDL-C) who were randomized to ERN versus placebo on a background of simvastatin therapy (with or without ezetimibe) to assess the association between baseline Lp-PLA2 activity and the rate of the composite primary end point (CV death, myocardial infarction, stroke, hospitalization for unstable angina, and symptom-driven revascularization). Participants randomized to ERN, but not those randomized to placebo, experienced a significant 8.9% decrease in LpPLA2. In univariate analysis, the highest quartile of LpPLA2 activity (>208 nmol/min/mL, Q4) was associated with higher event rates compared to the lower quartiles in the placebo group (log rank P = .032), but not in the ERN treated participants (log rank P = .718). However, in multivariate analysis, adjusting for sex, diabetes, baseline LDL-C, HDL-C, and triglycerides, there was no significant difference in outcomes between the highest Lp-PLA2 activity quartile versus the lower quartiles in both the placebo and the ERN groups. Among participants with stable CV disease on optimal medical therapy, elevated Lp-PLA2 was associated with higher CV events; however, addition of ERN mitigates this effect. This association in the placebo group was attenuated after multivariable adjustment, which suggests that Lp-PLA2 does not improve risk assessment beyond traditional risk factors.

Harmonization protocols for Lp-PLA2 activity reagents: An initial attempt in China

The autoantibody profile, which varies between races, has rarely been reported in Chinese Han systemic sclerosis (SSc) patients. The present study aims to investigate the autoantibody profile of Chinese Han SSc patients using a commercial line immunoassay.The prevalence of autoantibodies to Ro-52, PDGFR, Ku, PM75, PM100, Th/To, NOR90, Fib, RP155, RP11, CENP-B, CENP-A and Scl-70 were analyzed in serum samples obtained from healthy controls (n = 30), SSc patients (n = 320) and non-SSc connective-tissue disease patients (n = 100) using an Euroline Systemic Sclerosis Profile kit.SSc patients had increased prevalence of anti-RP11 (P = 0.032), anti-CENPB (P < 0.001), anti-CENPA (P = 0.001) and anti-Scl-70 (P < 0.001), but had decreased prevalence of anti-Ro-52 (P = 0.004), when compared to non-SSc CTDs. Furthermore, SSc patients had increased prevalence of anti-Ro-52 (P = 0.003), anti-CENPB (P = 0.034), anti-CENPA (P = 0.034) and anti-Scl-70 (P < 0.001), when compared to HCs. In addition, SSc patients with interstitial lung disease (ILD) had increased prevalence of anti-Ro-52 (P = 0.046) and anti-Scl-70 (P = 0.035), but had decreased prevalence of anti-CENPB (P < 0.001) and anti-CENPA (P < 0.001). Moreover, SSc patients with pulmonary arterial hypertension (PAH) had increased prevalence of anti-Ro-52 (P = 0.013) and decreased prevalence of anti-Scl-70 (P = 0.001). Anti-Ro-52 and anti-Scl-70 had increased values for predicting ILD in SSc patients, while anti-Ro-52 had increased values for predicting PAH in SSc patients.A commercial line immunoassay was used to evaluate the diagnostic value of autoantibodies in Chinese Han SSc patients. The results clearly indicate that the immunoblot assay has good diagnostic utility for SSc. Anti-Ro-52, anti-RP11, anti-CENPB, anti-CENPA and anti-Scl-70 are useful for diagnosing SSc in the Chinese Han population. Anti-Ro-52, anti-CENPB, anti-CENPA and anti-Scl-70 have a potential value for diagnosing ILD in SSc patients. Furthermore, anti-Ro-52 and anti-Scl-70 may be used to diagnose PAH in SSc patients.

Diabetes and dyslipidaemia are associated with oxidative stress independently of inflammation in long-term antiretroviral-treated HIV-infected patients

AimAgeing HIV-infected patients controlled by antiretroviral therapy (ART) frequently present age-related comorbidities, such as cardiovascular (CV) events, diabetes, dyslipidaemia, hypertension and chronic kidney disease (CKD). The prevalence of these comorbidities was evaluated in a cohort of long-term-monitored ART-controlled HIV-infected patients, then followed by a search into whether oxidative stress, like inflammation, might be associated with metabolic parameters and/or comorbidities. MethodsIncluded were 352 long-term ART patients who started with protease inhibitors (PIs) in 1997–1999. They were evaluated at their final visit, 11 years later, for previous CV events, prevalence of diabetes, LDL-related and atherogenic (high TG/HDL) dyslipidaemias, hypertension and CKD. Also measured were circulating biomarkers to explore oxidative stress (Lp-PLA2, oxLDL, oxLDL/LDL ratio, paraoxonase and arylesterase activities), inflammation/immune activation (hsCRP, hsIL-6, D dimer, soluble CD14, β2 microglobulin, cystatin C), adipokines and insulin resistance. Levels were compared in patients with and without each comorbidity or condition using non-parametric correlation tests and multivariate adjusted analyses. ResultsAt the final visit, 81.5% of patients were male and were aged (median, IQR) 49 years (45–56); BMI was 23.0 kg/m2 (21.1–25.4), CD4+ lymphocytes were 620 cells/mm3 (453–790) and 91.5% had undetectable HIV-1 viral loads. The prevalence of diabetes was 11%, and LDL-related dyslipidaemia 28%, atherogenic dyslipidaemia 9%, hypertension 28%, CKD 9% and previous CV events 9%. Diabetes and atherogenic dyslipidaemia were associated with increased oxidative stress and independently with inflammation. LDL-related dyslipidaemia and impaired fasting glucose were associated with increased oxidative stress. No association of these biomarkers was detected with hypertension, CKD and previous CV events. ConclusionIn long-term-treated HIV-infected patients with frequent comorbid conditions, oxidative stress could be contributing to diabetes and LDL-related and atherogenic dyslipidaemias independently of inflammation.

Lp-PLA2 Activity During Iron Depletion Treatment in Primary IO Patients

Lp-PLA2 Activity During Iron Depletion Treatment in Primary IO Patients

The role of phospholipase A2 in multiple Sclerosis: A systematic review and meta-analysis

Phospholipases A2 (PLA2) are a diverse group of enzymes that cleave the fatty acids of membrane phospholipids. They play critical roles in pathogenesis of neurodegenerative diseases such as multiple sclerosis by enhancing oxidative stress and initiating inflammation. The levels of PLA2 activity in MS patients compared to controls and role of inhibiting PLA2 activity on severity scores in different experimental models are not comprehensively assessed in the light of varying evidence from published studies. The objective of this systematic review is to determine the association between PLA2 activity and multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). We performed a systematic review of six studies that assessed PLA2 activity in MS patients compared to controls and nine studies that assessed PLA2 activity in EAE. sPLA2 nor Lp-PLA2 activity were not increased in MS compared to controls in five of those six studies. A difference in sPLA2 activity was only found in a study that measured the enzyme activity in urine. However, inhibiting cPLA2 or sPLA2 led to lower clinical severity or no signs of EAE in mice, and a lower incidence of EAE lesions compared to animals without cPLA2 inhibition. These findings indicate that PLA2 appears to play a role in the pathogenesis of EAE.

Lp-PLA2, scavenger receptor class B type I gene (SCARB1) rs10846744 variant, and cardiovascular disease.

BackgroundWe previously reported association of SCARB1 SNP rs10846744 with common carotid IMT (cIMT) and cardiovascular disease (CVD) events. Since rs10846744 has been reported in association with Lp-PLA2 mass and activity, we hypothesized that inflammatory pathways might mediate the association of rs10846744 with atherosclerosis.MethodsWe first examined association of rs10846744 in CVD in multiple large-scale consortium-based genome-wide association studies. We further examined 27 parameters of interest, including Lp-PLA2 mass and activity, inflammatory markers, and plasma phospholipid fatty acids, and fatty acid ratios in participants from the Multi-Ethnic Study of Atherosclerosis (MESA), as potential mediators in the pathway linking rs10846744 with cIMT and incident CVD. Finally, we examined the association of rs10846744 with Lp-PLA2 activity, cardiovascular outcomes, and interaction with the Lp-PLA2 inhibitor, darapladib, in the Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy (STABILITY) and Stabilization of Plaque using Darapladib-Thrombolysis in Myocardial Infarction 52 (SOLID-TIMI 52) studies.ResultsSCARB1 rs10846744 was associated with coronary artery disease events in CARDIoGRAMplusC4D (odds ratio 1.05; 95% CI [1.02, 1.07]; P = 1.4x10-4). In combined analysis across race/ethnic groups in MESA, rs10846744 was associated with Lp-PLA2 mass (P = 0.04) and activity (P = 0.001), homocysteine (P = 0.03), LDL particle number (P = 0.01), docosahexaenoic acid [DHA] (P = 0.01), docosapentaenoic acid [DPA] (P = 0.04), DPA/ eicosapentaenoic acid [EPA] ratio (P = 0.002), and DHA/EPA ratio (P = 0.008). Lp-PLA2 activity was identified as a mediator of rs10846744 with cIMT in a basic model (P = 8x10-5), but not after adjustment for CVD risk factors. There was no interaction or modifier effect of the Lp-PLA2 inhibitor darapladib assignment on the relationship between rs10846744 and major CVD events in either STABILITY or SOLID-TIMI 52.SummarySCARB1 rs10846744 is significantly associated with Lp-PLA2 activity, atherosclerosis, and CVD events, but Lp-PLA2 activity is not a mediator in the association of rs10846744 with cIMT in MESA.

Measuring lipoprotein‐associated phospholipase A2 activity in China: Protocol comparison and recalibration

Lp-PLA2 is a novel inflammation marker in cardiovascular disease. While several manufactures have registered Lp-PLA2 activity reagents, few studies have investigated the consistency among these assays. In this study, we compared and recalibrated Lp-PLA2 activity assays. Serum samples from 110 patients and 140 healthy individuals were collected for method comparison and reference interval validation, respectively. Fresh human serum pools (847 and 442U/L) were used for recalibration. Lp-PLA2 activity was analyzed using all five assays with a Beckman AU 5800 analyzer. Passing-Bablok regression equations and Bland-Altman plots were used to estimate the relationship and bias among the results. A 2.5% confidence interval (CI) and 97.5% CI were used to establish a laboratory reference interval. Assay imprecision varied from 0.8%-2.9%, while the overall coincidence rates ranged from 75.5%-98.2%. Passing-Bablok regression shows excellent linear correlation between Evermed and Diasys (R2 =0.999), while that between Diazyme and Evermed was poor (R2 =0.846). The R2 and correlation coefficient r among assays were 0.846-0.999 and 0.8947-0.9993, respectively. The mean bias percentages ranged from -71.5%-1.6% and -2.0%-11.6% before and after recalibration. As Diazyme and Diasys were not comparable, the Diazyme assay was not recalibrated. The reference intervals determined for Diasys, Evermed, Hengxiao, and Zybio were 184-605, 208-704, 81-328, and 273-696U/L, respectively. Our results indicate that recalibration increased assay agreement and also highlight the need for each laboratory to establish its own reference interval for Lp-PLA2 activity.

Lipoprotein-associated Phospholipase A2 and Coronary Heart Disease.

In the last decades, the role of inflammation in the pathogenesis of atherosclerosis has been the topic of intense research. Several markers of inflammation have shown predictive value for first and recurrent coronary events in patients without and with established Coronary Heart Disease (CHD). Among these markers, lipoprotein- associated phospholipase A2 (Lp-PLA2) has recently received considerable attention. In the present review, the potential role of Lp-PLA2 as a marker of CHD risk and as a therapeutic target is discussed. Elevated Lp- PLA2 mass and activity appears to be associated with increased risk for CHD, both in the general population and in patients with established CHD. However, it is unclear whether the measurement of Lp-PLA2 improves risk discrimination when incorporated in models that include traditional cardiovascular risk factors. Moreover, the lack of effect on CHD events of darapladib, a potent, selective Lp-PLA2 inhibitor, in two large, randomized, placebo-controlled trials and the mostly negative findings of genetic association studies suggest that Lp-PLA2 is unlikely to represent a causal factor in atherogenesis. Therefore, it is doubtful whether Lp-PLA2 will constitute a therapeutic target for the prevention of CHD.

Measurement of Lipoprotein-Associated Phospholipase A2 by Use of 3 Different Methods: Exploration of Discordance between ELISA and Activity Assays.

Lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme associated with inflammation, is used as a biomarker for cardiovascular disease risk. Both the concentration and activity of Lp-PLA2 have been shown to be clinically relevant. However, there is a discordance between the serum concentration of Lp-PLA2 measured by the standard ELISA-based immunoassays and the activity of this enzyme, leading to substantial discordance in risk categorization depending on assay format. We developed 2 LC-MS/MS-based assays to quantify serum Lp-PLA2 activity (multiple reaction monitoring detection of product) and concentration [stable isotope standards and capture by antipeptide antibody (SISCAPA) immunoaffinity], and we investigated their correlation to commercially offered colorimetric activity and immunometric concentrations assays. Associations between Lp-PLA2 and lipoproteins and the effect of selected detergents in liberating Lp-PLA2 were evaluated by use of immunoprecipitation and Western blot analyses. Serum Lp-PLA2 concentrations measured by quantitative SISCAPA-mass spectrometry were substantially higher than concentrations typically measured by immunoassay and showed an improved agreement with Lp-PLA2 activity. With detergents, liberation of Lp-PLA2 from lipoprotein complexes dramatically increased the amount of protein detected by immunoassay and improved the agreement with activity measurements. Quantitative analysis of Lp-PLA2 concentration and activity by LC-MS/MS assays provided key insight into resolving the well-documented discordance between Lp-PLA2 concentration (determined by immunoassay) and activity. Quantitative detection of Lp-PLA2 by immunoassay appears to be strongly inhibited by interaction of Lp-PLA2 with lipoprotein. Together, the results illustrate the advantages of quantitative LC-MS/MS for measurement of Lp-PLA2 concentration (by SISCAPA) and activity (by direct product detection).