Lipoprotein-associated Phospholipase A2 Activity Research Articles

ApoB, small-dense LDL-C, Lp(a), LpPLA2 activity, and cognitive change.

To examine the association of specific lipoproteins/inflammatory enzyme with cognitive change. We examined the association of apolipoprotein B (ApoB), small-dense low-density lipoprotein cholesterol (sdLDL-C), lipoprotein (a) (Lp[a]), and lipoprotein-associated phospholipase A2 (LpPLA2) activity with 15-year change in Delayed Word Recall Test, Digit Symbol Substitution Test (DSST), Word Fluency Test (WFT), and overall summary score in 9,350 participants in the Atherosclerosis Risk in Communities study. We assessed interaction by race, sex, education, APOE ε4 status, and statin use. We also addressed questions of informative missingness, the role of stroke, and the influence of fasting status. The mean (SD) age was 63.4 (5.7) years; 56.4% were women and 17.4% were black. We observed faster cognitive decline on DSST and global z scores with every 10-mg/dL higher sdLDL-C level (Δ DSST z score, -0.010; 95% confidence interval [CI] -0.017, -0.002 and Δ global z score, -0.011; -0.021, -0.001) and the highest vs the lowest ApoB quintiles (Δ DSST z score, -0.092; -0.0164, -0.019 and Δ global z score, -0.101; -0.200, -0.002). Association for the ApoB quintiles with Δ global z score (-0.10) was comparable with that of having 1 APOE ε4 allele (-0.11). Higher Lp(a) was associated with slower decline in DSST, WFT, and global z scores. LpPLA2 activity was not associated with cognitive change. Results were similar in sensitivity analyses. The associations of sdLDL-C or Lp(a) on cognitive change were more pronounced in statin users. Optimal control of atherogenic lipoproteins such as ApoB and sdLDL-C in midlife for cardiovascular health may also benefit late-life cognitive health.

Metabolically unhealthy overweight individuals have high lysophosphatide levels, phospholipase activity, and oxidative stress

Metabolically unhealthy overweight (MUO) individuals and metabolically healthy overweight (MHO) individuals differ in biomarkers of atherogenesis. Metabolomic approaches enable studies of the metabolic variables underlying these differences. We determined the metabolomes in plasma samples from 34 MUO and 34 MHO individuals matched for sex, age, and body mass index (BMI) to identify potential metabolic markers or pathways associated with atherogenic traits. This analysis revealed that the MUO group had significantly higher levels of glycolic acid, 6 lysophosphatidylethanolamines (lysoPEs), and 12 lysophosphatidylcholines (lysoPCs). Although the two groups had similar total body fat percentages and lean body masses, MUO individuals had larger visceral fat areas (VFAs). They also had greater circulating lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and higher levels of oxidized low-density lipoprotein (ox-LDL) and urinary 8-epi-prostaglandin F2α (8-epi-PGF2α), reflecting higher risks for oxidative and lipid-related tissue damage. The following measures were positively correlated: VFA and ox-LDL; ox-LDL and Lp-PLA2 activity; and lysoPC, lysoPE, and 8-epi-PGF2α levels. Chronic plasma lysoPC increases were associated with atherogenic traits, higher levels of mean ox-LDL, 8-epi-PGF2α, Lp-PLA2, and visceral fat accumulation in MUO compared to MHO individuals. This panel of plasma metabolites distinguishes MUO from MHO individuals and will enable future research on fat dysregulation and obesity.

Lp-PLA2 activity and mass and CRP are associated with incident symptomatic peripheral arterial disease

Long follow up is needed in prospective cohort study evaluation of plasma biomarkers for incident peripheral arterial disease (PAD) Middle-aged PAD-free individuals from the cardiovascular cohort of the Malmö Diet and Cancer study (n = 5550; 1991–94) were followed prospectively for a median time of 23.4 years. The plasma biomarkers lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and mass, proneurotensin, and CRP, were studied in relation to incidence of PAD until December 31st, 2016. The diagnosis of PAD could be validated and confirmed in 98%. Cox regression was used to calculate hazard ratios (HR) per 1 standard deviation increment of each respective log transformed plasma biomarker. Cumulative incidence of PAD was 4.4% (men 5.9%, women 3.3%). Adjusting for age, gender, smoking, body mass index, hypertension, diabetes mellitus, Lp-PLA2 activity (HR 1.33; 95% CI 1.17–1.52), Lp-PLA2 mass (HR 1.20; 95% CI 1.05–1.37) and CRP (HR 1.55; 95% CI 1.36–1.76) remained independently associated with incident PAD. The plasma biomarkers Lp-PLA2 activity and mass, and CRP were markers of PAD risk, implying that they might be useful biomarkers for subclinical atherosclerosis and atherosclerotic disease.

Interleukin-6 and lipoprotein-associated phospholipase A2 are associated with functional trajectories.

Background/ObjectivesInflammatory biomarkers have been associated with stroke and mortality, but inflammation may also have detrimental effects beyond acute events. We hypothesized that serum concentrations of interleukin-6 (IL6) and lipoprotein-associated phospholipase A2 (LpPLA2) were inversely associated with long-term functional decline independently of vascular risk factors, stroke and myocardial infarction (MI) occurring during follow-up.DesignProspective population based cohort studySettingThe Northern Manhattan StudyParticipants (including the sample size)Race/ethnically diverse stroke-free individuals in northern Manhattan aged ≥40 years (n = 3298).InterventionNoneMeasurementsAnnual functional assessments with the Barthel index (BI), for a median of 13 years. BI was analyzed as a continuous variable (range 0–100). Baseline demographics, risk factors, and laboratory studies were collected, including IL6 (n = 1679), LpPLA2 mass (n = 1912) and activity (n = 1937). Separate mixed models estimated standardized associations between each biomarker and baseline functional status and change over time, adjusting for demographics, vascular risk factors, social variables, cognition, and depression measured at baseline, and stroke and MI occurring during follow-up.ResultsMean age was 69 (SD 10) years, 35% were male, 53% Hispanic, 74% hypertensive, and 16–24% diabetic. LogIL6 was associated with decline in BI over time (-0.13 points per year, 95% CI -0.24, -0.02) and marginally with baseline BI (-0.20, 95% CI -0.40, 0.01). LpPLA2 activity levels were associated with baseline BI (-0.36, 95% CI -0.68, -0.04) but not change over time, and LpPLA2 mass levels were not associated with either.ConclusionIn this large population-based study, higher serum inflammatory biomarker levels were associated with disability, even when adjusting for baseline covariates and stroke and MI occurring during follow-up.

No effect of vitamin D administration plus dietary intervention on emerging cardiovascular risk factors in patients with metabolic syndrome

BackgroundPatients with metabolic syndrome (MetS) have low serum 25-hydroxyvitamin D (25(OH)VitD) levels. Low 25(OH)VitD has been associated with several emerging cardiovascular disease (CVD) risk factors, while VitD administration may ameliorate them. AimTo study the effect of 25(OH)VitD supplementation plus dietary instructions on novel CVD risk factors in MetS patients. MethodsThis is a pre-specified analysis of a previously published study. Patients with MetS (n = 50, 52 ± 10 years) were given dietary instructions and were randomized to receive either 25(OH)VitD, 2.000 IU/day p.o. (Suppl group) or nothing (No-Suppl group). Serum 25(OH)VitD, small dense low-density lipoprotein cholesterol (sdLDL), as well as lipoprotein-associated phospholipase A2 (LpPLA2) activity, leptin and adiponectin levels were measured at baseline and 3 months later. ResultsIn the Suppl group 25(OH)VitD levels increased by 90% [from 16.1 (3.3–35.1) to 30.6 (8.4–67.6) ng/mL, p = 0.001] and by 33.3% [from 9.9 (4.0–39.6) to 13.2 (3.5–36.8) ng/mL, p = NS] in the No-Suppl group. sdLDL serum levels, mean LDL size, LpPLA2 activity, leptin, adiponectin concentration and leptin to adiponectin ratio did not change significantly in both groups. ConclusionIn this small study the administration of 25(OH)VitD plus dietary intervention in patients with MetS were not associated with any significant change in various emerging CVD risk factors. (NCT01237769 ClinicalTrials.gov).

Performance Characteristics and Clinical Value of the Lipoprotein-Associated Phospholipase A2 by an Enzymatic Kinetic Method.

To analyze the performance characteristics, stability, and clinical value of lipoprotein-associated phospholipase A2 (Lp-PLA2) using an enzymatic kinetic method. The performance characteristics included reference intervals, precision, and accuracy. We assessed Lp-PLA2 stability by comparing Lp-PLA2 changes under different conditions. Lp-PLA2 was determined in the following groups: control individuals, patients with coronary heart disease (CHD), patients of different lipid subgroups within CHD, and patients with high total cholesterol (TC). Also, correlations between Lp-PLA2 and traditional cardiovascular risk factors were assessed. The mean (SD) reference interval of serum Lp-PLA2 activity was 451 (113) U per L with sex differences. Inter- and intra-assay precision revealed coefficients of variance (CVs) of 1.81% to 2.63% and 1.43% to 1.77%. The average bias was 0.33%. Lp-PLA2 activity was stable. In the CHD group, high-lipid subgroups, and high-TC group, Lp-PLA2 was elevated, and correlation was observed between Lp-PLA2 and traditional risk factors. Lp-PLA2 activity has important clinical value in CHD.

Iron Homeostasis Determines Fate of Human Pluripotent Stem Cells Via Glycerophospholipids-Epigenetic Circuit.

Iron homeostasis is crucial for a variety of biological processes, but the biological role of iron homeostasis in pluripotent stem cells (PSCs) remains largely unknown. The present study aimed to determine whether iron homeostasis is involved in maintaining the pluripotency of human PSCs (hPSCs). We found that the intracellular depletion of iron leads to a rapid downregulation of NANOG and a dramatic decrease in the self-renewal of hPSCs as well as spontaneous and nonspecific differentiation. Moreover, long-term depletion of iron can result in the remarkable cell death of hPSCs via apoptosis and necrosis pathways. Additionally, we found that the depletion of iron increased the activity of lipoprotein-associated phospholipase A2 (LP-PLA2) and the production of lysophosphatidylcholine, thereby suppressing NANOG expression by enhancer of zeste homolog 2-mediated trimethylation of histone H3 lysine 27. Consistently, LP-PLA2 inhibition abrogated iron depletion-induced loss of pluripotency and differentiation. Altogether, the findings of our study demonstrates that iron homeostasis, acting through glycerophospholipid metabolic pathway, is essential for the pluripotency and survival of hPSCs. Stem Cells 2019;37:489-503.

Short-term exposure to ambient air pollution and circulating biomarkers of endothelial cell activation: The Framingham Heart Study

BackgroundShort-term exposure to air pollution has been associated with cardiovascular events, potentially by promoting endothelial cell activation and inflammation. A few large-scale studies have examined the associations and have had mixed results. MethodsWe included 3820 non-current smoking participants (mean age 56 years, 54% women) from the Framingham Offspring cohort examinations 7 (1998–2001) and 8 (2005–2008), and Third Generation cohort examination 1 (2002–2005), who lived within 50 km of a central monitoring station. We calculated the 1- to 7-day moving averages of fine particulate matter (PM2.5), black carbon (BC), sulfate (SO42-), nitrogen oxides (NOx), and ozone before examination visits. We used linear mixed effect models for P-selectin, monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1, lipoprotein-associated phospholipase A2 activity and mass, and osteoprotegerin that were measured up to twice, and linear regression models for CD40 ligand and interleukin-18 that were measured once, adjusting for demographics, life style and clinical factors, socioeconomic position, time, and meteorology. ResultsWe found negative associations of PM2.5 and BC with P-selectin, of ozone with MCP-1, and of SO42- and NOx with osteoprotegerin. At the 5-day moving average, a 5 µg/m3 higher PM2.5 was associated with 1.6% (95% CI: − 2.8, − 0.3) lower levels of P-selectin; a 10 ppb higher ozone was associated with 1.7% (95% CI: − 3.2, − 0.1) lower levels of MCP-1; and a 20 ppb higher NOx was associated with 2.0% (95% CI: − 3.6, − 0.4) lower levels of osteoprotegerin. ConclusionsWe did not find evidence of positive associations between short-term air pollution exposure and endothelial cell activation. On the contrary, short-term exposure to higher levels of ambient pollutants were associated with lower levels of P-selectin, MCP-1, and osteoprotegerin in the Framingham Heart Study.

Lipoprotein-associated phospholipase A2 predicts cardiovascular events in dialyzed patients.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a serine lipase that enhances the instability of the atherosclerotic plaques. While in the general and cardiac population Lp-PLA2 is recognized as an important determinant of cardiovascular (CV) accidents, no data are available for the renal population. The aim of this study was to evaluate the relationship between Lp-PLA2 and acute CV events in hemodialyzed patients. We enrolled 102 dialyzed patients, 63% male, age 71years (59-78), 35% with diabetes, 54% hypertension, 40% coronary artery disease and 31% peripheral vascular disease. They were investigated for Lp-PLA2 (cut-off < 194nmol/min/ml), lipoprotein profile and the occurrence of acute CV events and death in the subsequent 3years of follow-up. The median (interquartile ranges) levels of Lp-PLA2, total-, HDL-, LDL-cholesterol and ApoB/ApoA lipoprotein ratio were 184.5 (156.5-214.5) nmol/min/ml, 158 (127-191) mg/dl, 41 (33-51) mg/dl, 79 (63-102) mg/dl and 0.72 (0.58-0.89), respectively. In 42% of patients, Lp-PLA2 was > 194nmol/min/ml and total- and LDL-cholesterol were higher, as well as CV morbidity and mortality. During follow-up, 51% of patients developed at least one CV event; the median survival time was 36 months, with a total and CV mortality of 42 and 29%, respectively. At multivariate Cox regression, Lp-PLA2 > 194nmol/min/ml (HR = 2.98, p = 0.005), age (HR = 1.03, p = 0.029), diabetes (HR = 2.86, p = 0.002) and hypertension (HR = 2.93, p = 0.002) were independently associated with time to CV events. Lp-PLA2 activity is elevated among dialyzed patients and is an independent risk factor for acute CV events in a mean follow-up of 3years.

Hemodynamic Deterioration of Surgically Implanted Bioprosthetic Aortic Valves

BackgroundDysmetabolic profile has been associated with native aortic valve stenosis. However, there are limited data on the effects of an atherogenic milieu and its potential implications on the structural and hemodynamic deterioration of aortic bioprosthetic valves. ObjectivesThis prospective longitudinal study sought to determine the predictors and impact on outcomes of hemodynamic valve deterioration (HVD) of surgically implanted aortic bioprostheses. MethodsA total of 137 patients with an aortic bioprosthesis implanted for a median time of 6.7 (interquartile range: 5.1 to 9.1) years prospectively underwent a first (baseline) assessment with complete Doppler echocardiography, quantitation of bioprosthesis leaflet calcification by multidetector computed tomography (CT), and a fasting blood sample to assess cardiometabolic risk profile. All patients underwent a second (follow-up) Doppler echocardiography examination at 3 (interquartile range: 2.9 to 3.3) years post-baseline visit. HVD was defined by an annualized change in mean transprosthetic gradient ≥3 mm Hg/year and/or worsening or transprosthetic regurgitation by ≥1/3 class. The primary endpoint was a nonhierarchical composite of death from any cause or aortic reintervention procedure (redo surgical valve replacement or transcatheter valve-in-valve implantation) for bioprosthesis failure. ResultsThirty-four patients (25.6%) had leaflet calcification on baseline CT, and 18 patients (13.1%) developed an HVD between baseline and follow-up echocardiography. Fifty-two patients (38.0%) met the primary endpoint during subsequent follow-up after the second echocardiographic examination. Leaflet calcification (hazard ratio [HR]: 2.58; 95% confidence interval [CI]: 1.35 to 4.82; p = 0.005) and HVD (HR: 5.12; 95% CI: 2.57 to 9.71; p < 0.001) were independent predictors of the primary endpoint. Leaflet calcification, insulin resistance (homeostatic model assessment index ≥2.7), lipoprotein-associated phospholipase A2 activity (Lp-PLA2 per 0.1 nmol/min/ml increase), and high level of proprotein convertase subtilisin/kexin 9 (PCSK9) (≥305 ng/ml) were associated with the development of HVD after adjusting for age, sex, and time interval since aortic valve replacement. ConclusionsHVD identified by Doppler echocardiography is independently associated with a marked increase in the risk of valve reintervention or mortality in patients with a surgical aortic bioprosthesis. A dysmetabolic profile characterized by elevated plasma Lp-PLA2, PCSK9, and homeostatic model assessment index was associated with increased risk of HVD. The presence of leaflet calcification as detected by CT was a strong predictor of HVD, providing incremental risk-predictive capacity.

Integrated Human Evaluation of the Lysophosphatidic Acid Pathway as a Novel Therapeutic Target in Atherosclerosis

Variants in the PLPP3 gene encoding for lipid phosphate phosphohydrolase 3 have been associated with susceptibility to atherosclerosis independently of classical risk factors. PLPP3 inactivates lysophosphatidic acid (LPA), a pro-inflammatory, pro-thrombotic product of phospholipase activity. Here we performed the first exploratory analysis of PLPP3, LPA, and LPA receptors (LPARs 1–6) in human atherosclerosis. PLPP3 transcript and protein were repressed when comparing plaques versus normal arteries and plaques from symptomatic versus asymptomatic patients, and they were negatively associated with risk of adverse cardiovascular events. PLPP3 localized to macrophages, smooth muscle, and endothelial cells (ECs) in plaques. LPAR 2, 5, and especially 6 showed increased expression in plaques, with LPAR6 localized in ECs and positively correlated to PLPP3. Utilizing in situ mass spectrometry imaging, LPA and its precursors were found in the plaque fibrous cap, co-localizing with PLPP3 and LPAR6. In vitro, PLPP3 silencing in ECs under LPA stimulation resulted in increased expression of adhesion molecules and cytokines. LPAR6 silencing inhibited LPA-induced cell activation, but not when PLPP3 was silenced simultaneously. Our results show that repression of PLPP3 plays a key role in atherosclerosis by promoting EC activation. Altogether, the PLPP3 pathway represents a suitable target for investigations into novel therapeutic approaches to ameliorate atherosclerosis.

The correlation between lipoprotein-associated phospholipase A2 and severity of coronary artery diseases

Objective To investigate the relationship between lipoprotein-associated phospholipase A2(Lp-PLA2) activity and the severity of coronary artery diseases. Methods A case-control study was conducted to select 231 patients with positive coronary angiography results in Beijing Huaxin Hospital. They were divided into two groups (untreated goup: 147 cases; the medication group: 84 cases) according to whether taking statins. 99 cases were included in the healthy control group. In the untreated group, all male patients were grouped according to the number of diseased coronary branches (43 cases were in single vessel lesion group and 52 cases were in multi vessel disease group) or to the Gensini score (32 cases were in low score group, 36 cases were in middle score group and 27 cases were in high score group). The clinical data were collected by detecting serum atherosclerotic markers such as Lp-PLA2, total cholesterol (CHOL), low-density lipoprotein (LDL). The number of vessels involved in coronary artery disease, the position of the lesion and the degree of stenosis were confirmed by percutaneous coronary intervention (PCI). Statistical evaluations were performed using t-test, variance analysis, Mann-Whitney U test and Spearman correlation analysis. Results The differences among untreated group, the medication group and the control group were statistically significant, of which the Lp-PLA2 level was (561.9±158.5) U/L, (373.2±124.7) U/L and (467.4± 130.4) U/L respectively. Compared with single branch disease group, the Lp-PLA2 level in the multiple branches disease group was increased dramatically. Additionally, the level of Lp-PLA2 in high Gensini score group was (618.7 ±165.4) U/L, significantly higher than the low score group (517.3± 191.7) U/L. Conclusion Lp-PLA2 activity was associated with the severity of Coronary Artery Diseases, which can provide the evidence for the follow-up treatment programs. (Chin J Lab Med, 2018, 41: 425-429) Key words: Lipoprotein-associated phospholipase A2; Atherosclerosis Coronary angiography

Lp-PLA2 activity is associated with increased risk of diabetic retinopathy: a longitudinal disease progression study

Aims/hypothesisThe aim of the study was to examine the association between lipoprotein-associated phospholipase A2 (Lp-PLA2) activity levels and incident diabetic retinopathy and change in retinopathy grade.MethodsThis was a cohort study of diabetic participants with serum collected at baseline and routinely collected diabetic retinal screening data. Participants with type 2 diabetes from the GoDARTS (Genetics of Diabetes Audit and Research in Tayside Scotland) cohort were used. This cohort is composed of individuals of white Scottish ancestry from the Tayside region of Scotland. Survival analysis accounting for informative censoring by modelling death as a competing risk was performed for the development of incident diabetic retinopathy from a disease-free state in a 3 year follow-up period (n = 1364) by stratified Lp-PLA2 activity levels (in quartiles). The same analysis was performed for transitions to more severe grades.ResultsThe hazard of developing incident diabetic retinopathy was 2.08 times higher (95% CI 1.64, 2.63) for the highest quartile of Lp-PLA2 activity compared with the lowest. Higher Lp-PLA2 activity levels were associated with a significantly increased risk for transitions to all grades. The hazards of developing observable (or more severe) and referable (or more severe) retinopathy were 2.82 (95% CI 1.71, 4.65) and 1.87 (95% CI 1.26, 2.77) times higher for the highest quartile of Lp-PLA2 activity compared with the lowest, respectively.Conclusions/interpretationHigher Lp-PLA2 levels are associated with increased risk of death and the development of incident diabetic retinopathy, as well as transitions to more severe grades of diabetic retinopathy. These associations are independent of calculated LDL-cholesterol and other traditional risk factors. Further, this biomarker study shows that the association is temporally sensitive to the proximity of the event to measurement of Lp-PLA2.

Inflammatory markers and the risk of dementia and Alzheimer's disease: A meta-analysis

IntroductionInflammatory markers are often elevated in patients with dementia, including Alzheimer's disease (AD). However, it remains unclear whether inflammatory markers are associated with the risk of developing dementia. MethodsWe searched PubMed, Embase, and Cochrane library for prospective population-based studies reporting associations between inflammatory markers and all-cause dementia or AD. We used random effects meta-analyses to obtain pooled hazard ratios (HRs) and 95% confidence intervals of inflammatory markers (highest vs. lowest quantile) for all-cause dementia and AD. ResultsFifteen articles from 13 studies in six countries reported data that could be meta-analyzed. C-reactive protein (HR = 1.37 [1.05; 1.78]), interleukin-6 (HR = 1.40 [1.13; 1.73]), α1-antichymotrypsin (HR = 1.54 [1.14; 2.80]), lipoprotein-associated phospholipase A2 activity (HR = 1.40 [1.03; 1.90]), and fibrinogen were each associated with all-cause dementia, but neither was significantly associated with AD. DiscussionSeveral inflammatory markers are associated with an increased risk of all-cause dementia; however, these markers are not specific for AD. Whether inflammatory markers closely involved in AD pathology are associated with the risk of AD remains to be elucidated.

Novel enzymatic method for assaying Lp-PLA2 in serum

BackgroundMeasurement of lipoprotein-associated phospholipase A2 (Lp-PLA2) can be used as an adjunct to traditional cardiovascular risk factors for identifying individuals at higher risk of cardiovascular events. This can be performed by quantification of the protein concentration using an ELISA platform or by measuring Lp-PLA2 activity using platelet-activating factor (PAF) analog as substrate. Here, an enzymatic Lp-PLA2 activity assay method using 1-O-Hexadecyl-2-acetyl-rac-glycero-3-phosphocholine (rac C16 PAF) was developed. MethodsThe newly revealed substrate specificity of lysoplasmalogen-specific phospholipase D (lysophospholipase D (LysoPLD)) was exploited. Lp-PLA2 hydrolyzes 1-O-Hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16 PAF) to 1-O-Hexadecyl-2-hydroxy-sn-glycero-3-phosphocholine (LysoPAF). LysoPLD acted on LysoPAF, and the hydrolytically released choline was detected by choline oxidase. ResultsRegression analysis of Lp-PLA2 activity measured by the enzymatic Lp-PLA2 activity assay vs. two chemical Lp-PLA2 activity assays, i.e. LpPLA2 FS and PLAC® test, and ELISA, gave the following correlation coefficients: 0.990, 0.893 and 0.785, respectively (n = 30). ConclusionAdvantages of this enzymatic Lp-PLA2 activity assay compared with chemical Lp-PLA2 methods include the following; (i) only requires two reagents enabling a simple two-point linear calibration method with one calibrator (ii) no need for inhibitors of esterase-like activity in serum.

Met117 oxidation leads to enhanced flexibility of cardiovascular biomarker- lipoprotein- associated phospholipase A2 and reduced substrate binding affinity with platelet-activating factor

Human Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an important biomarker for cardiovascular diseases and a therapeutically important drug target against Atherosclerosis. It has the ability to hydrolyze various oxidized low density lipoproteins (LDL) and generates potent pro-inflammatory signaling molecules. Both physiological and non-physiological oxidants have been reported to inhibit Lp-PLA2 activity. The mechanism of the enzyme inhibition due to oxidation of surface exposed Met117 at the structural level is not clearly understood. In the present work, molecular dynamics (MD) simulation and Essential dynamics (ED) has been used in tandem with molecular docking approach to understand the structural alteration in Lp-PLA2 upon Met117 oxidation. Further, the binding of substrate, Platelet-activating factor (PAF) with the wild type and oxidized form have also been investigated. Our results showed that Met117 oxidation caused enhanced flexibility and decreased compactness in oxidized state. PAF binding interaction with oxidized protein was mediated only through hydrophobic interactions. MD simulation studies revealed that the oxidized protein failed to firmly bind PAF. Our present findings will help understand the mechanism of Lp-PLA2 inhibition under oxidative stress.

Usefulness of Lipoprotein-Associated Phospholipase A2 Activity and C-Reactive Protein in Identifying High-Risk Smokers for Atherosclerotic Cardiovascular Disease (from the Atherosclerosis Risk in Communities Study)

Despite the causal role of cigarette smoking in atherosclerotic cardiovascular disease (ASCVD), the underlying mechanisms are not fully understood. We evaluated the joint relation between smoking and inflammatory markers with ASCVD risk. We tested cross-sectional associations of self-reported smoking status (never, former, current) and intensity (packs/day) with lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and high-sensitivity C-reactive protein (hsCRP) in 10,506 Atherosclerosis Risk in Communities participants at Visit 4 (1996 to 1998). Using Cox hazard models adjusted for demographic and traditional ASCVD risk factors, we examined the associations of smoking status and intensity with incident adjudicated ASCVD events (n = 1,745 cases) over an average of 17 years, stratified by Lp-PLA2 and hsCRP categories. Greater packs/day smoked was linearly associated with higher levels of both Lp-PLA2 and hsCRP among current smokers. Compared with never smokers, the hazard ratio for incident ASCVD in current smokers was 2.04 (95% CI 1.76 to 2.35). Among current smokers, the risk for ASCVD per 1 pack/day greater was 1.39 (1.10 to 1.76). Both Lp-PLA2 activity ≥253 nmol/min/ml and hsCRP >3 mg/L identified current smokers at the highest risk for incident ASCVD, with similar hazard ratios. hsCRP risk-stratified current smokers better based on intensity. Among current smokers, hsCRP improved ASCVD prediction beyond traditional risk factors better than Lp-PLA2 (C-statistic 0.675 for hsCRP vs 0.668 for Lp-PLA2, p = 0.001). In this large cohort with long follow-up, we found a dose-response relation between smoking intensity with Lp-PLA2 activity, hsCRP, and ASCVD events. Although both Lp-PLA2 activity and hsCRP categories identified high risk among current smokers, hsCRP may better stratify risk of future ASCVD.

Lipoprotein-associated phospholipase A₂ activity is increased in patients with definite familial hypercholesterolemia compared with other forms of hypercholesterolemia

Background and AimLipoprotein-associated phospholipase A2 (Lp-PLA2) plays a key role in atherosclerosis development. It is considered a marker of increased risk of cardiovascular disease (CVD) and plaque vulnerability. Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated plasma levels of low-density lipoprotein cholesterol and a higher prevalence of early CVD.Our aim was to evaluate the differences in Lp-PLA2 activity in a population of hypercholesterolemic patients with and without definite FH. Methods and ResultsHypercholesterolemic patients were consecutively recruited. Definite FH was defined according to Dutch Lipid Clinic Network criteria ≥8. All patients underwent routine clinical examination and biological assessments and Lp-PLA2 activity was measured in blood samples.Among 469 patients, 118 had a definite diagnosis of FH. Lp-PLA2 activity was significantly higher in definite FH patients compared to non-definite FH patients (206.5 ± 54.5 vs. 180.8 ± 48.4 nmol/min/mL, p < 0.0001). Lp-PLA2 positively correlated with total cholesterol, LDL-C and apolipoprotein B and negatively with HDL-C and apolipoprotein A-1. In multivariate analysis, definite FH diagnosis, LDL-C, HDL-C and statin treatment remained correlates of Lp-PLA2 independently of systolic blood pressure. ConclusionsLp-PLA2 activity was higher in definite FH than in non-definite FH patients independently of LDL-C levels and statin treatment. These results highlight the particular phenotype of FH subjects among hypercholesterolemic patients. As increased Lp-PLA2 activity suggests, FH patients exhibit higher arterial inflammation that may contribute to their high cardiovascular risk. Our results reinforce the potential beneficial role of statins pleiotropic effects and the need for proper identification and treatment of FH patients.

HDL functionality and cardiovascular outcome among nondialysis chronic kidney disease patients [S

CVD remains the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). CKD profoundly affects HDL composition and functionality, but whether abnormal HDL independently contributes to cardiovascular events in CKD patients remains elusive. In the present study, we assessed whether compositional and functional properties of HDL predict cardiovascular outcome among 526 nondialysis CKD patients who participate in the CARE FOR HOMe study. We measured HDL cholesterol, the content of HDL-associated proinflammatory serum amyloid A (SAA), and activities of the HDL enzymes paraoxonase and lipoprotein-associated phospholipase A2 (Lp-PLA2). In addition, we assessed the antioxidative activity of apoB-depleted serum. During a mean follow-up of 5.1 ± 2.1 years, 153 patients reached the predefined primary endpoint, a composite of atherosclerotic cardiovascular events including cardiovascular mortality and death of any cause. In univariate Cox regression analyses, lower HDL-cholesterol levels, higher HDL-associated SAA content, and lower paraoxonase activity predicted cardiovascular outcome, while Lp-PLA2 activity and antioxidative capacity did not. HDL-cholesterol and HDL-paraoxonase activity lost their association with cardiovascular outcome after adjustment for traditional cardiovascular and renal risk factors, while SAA lost its association after further adjustment for C-reactive protein. In conclusion, our data suggest that neither HDL quantity nor HDL composition or function independently predict cardiovascular outcome among nondialysis CKD patients.

Lipoprotein-Associated Phospholipase A2 Activity Level may be complementary to Cardiactroponin I as a Biomarker for Acute Myocardial Infarction in Chinese Patients with Chest Pain

Lipoprotein-Associated Phospholipase A2 Activity Level may be complementary to Cardiactroponin I as a Biomarker for Acute Myocardial Infarction in Chinese Patients with Chest Pain