Plasma lipoprotein-associated phospholipase A2 levels in heart failure: association with mortality in the community

Lipoprotein-Associated Phospholipase A2 Correlates with Reduced Left Ventricle Ejection Fraction in Hemodialysis Patients

OBJECTIVE

Reduced left ventricular ejection fraction (LVEF) is common in hemodialysis (HD) patients. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is considered an important determinant of cardiovascular events. The aim of the study was to evaluate the relationship between Lp-PLA2 and LVEF in HD patients.

METHODS

Fifty-seven HD patients with coronary heart disease were enrolled. Predialysis and postdialysis venous whole blood samples were collected. The patients were divided into preserved and reduced LVEF groups. The relationship between Lp-PLA2 and LVEF was assessed.

RESULTS

A significant difference in C-reactive protein (CRP) and Lp-PLA2 was observed, with higher levels noted in patients with reduced LVEF (P ≤ .001). Both Lp-PLA2 and CRP were negatively correlated with LVEF in the HD patients. Only Lp-PLA2 remained associated with LVEF in multiple regression analysis.

CONCLUSION

Lipoprotein-associated phospholipase A2 levels are associated with LVEF and could potentially be used to evaluate chronic heart failure with reduced LVEF in HD patients for risk stratification management.

Lp-PLA2 as a biomarker and its possible associations with SARS-CoV-2 infection

Lp-PLA2 is an enzyme encoded by the PLA2G7 gene located at chromosome 6p12-21, which is included in different signal transduction pathways. The potential of serum levels of Lp-PLA2 as a marker of inflammation quantifying cardio-metabolic risk, renal impairment and oxidative stress has been explored in earlier studies. It has also been used in chronic obstructive pulmonary disease, hepatic disease, metabolic conditions and exercise tolerance. Additionally, it shows promising evidence for the assessment of risk for certain cardiovascular conditions in otherwise seemingly healthy individuals. COVID-19 has affected life and the economy globally. The identification of biomarkers to assess the sickness and treatment plan is the need of the hour. This review summarizes the pathophysiological inter-relationship between serum levels of Lp-PLA2 and COVID-19. The authors hypothesize that the estimation of Lp-PLA2 levels may help in the early identification of risk and thus may play a beneficial role in the proactive management of COVID-19.

Longitudinal cohorts for harnessing the electronic health record for disease prediction in a US population

PURPOSE

The depth and breadth of clinical data within electronic health record (EHR) systems paired with innovative machine learning methods can be leveraged to identify novel risk factors for complex diseases. However, analysing the EHR is challenging due to complexity and quality of the data. Therefore, we developed large electronic population-based cohorts with comprehensive harmonised and processed EHR data.

PARTICIPANTS

All individuals 30 years of age or older who resided in Olmsted County, Minnesota on 1 January 2006 were identified for the discovery cohort. Algorithms to define a variety of patient characteristics were developed and validated, thus building a comprehensive risk profile for each patient. Patients are followed for incident diseases and ageing-related outcomes. Using the same methods, an independent validation cohort was assembled by identifying all individuals 30 years of age or older who resided in the largely rural 26-county area of southern Minnesota and western Wisconsin on 1 January 2013.

FINDINGS TO DATE

For the discovery cohort, 76 255 individuals (median age 49; 53% women) were identified from which a total of 9 644 221 laboratory results; 9 513 840 diagnosis codes; 10 924 291 procedure codes; 1 277 231 outpatient drug prescriptions; 966 136 heart rate measurements and 1 159 836 blood pressure (BP) measurements were retrieved during the baseline time period. The most prevalent conditions in this cohort were hyperlipidaemia, hypertension and arthritis. For the validation cohort, 333 460 individuals (median age 54; 52% women) were identified and to date, a total of 19 926 750 diagnosis codes, 10 527 444 heart rate measurements and 7 356 344 BP measurements were retrieved during baseline.

FUTURE PLANS

Using advanced machine learning approaches, these electronic cohorts will be used to identify novel sex-specific risk factors for complex diseases. These approaches will allow us to address several challenges with the use of EHR.

Integrative serum metabolomics and network analysis on mechanisms exploration of Ling-Gui-Zhu-Gan Decoction on doxorubicin-induced heart failure mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ling-Gui-Zhu-Gan Decoction (LGZGD) formula, derived from traditional Chinese medicine (TCM), has definitive clinical efficacy in the treatment of heart failure (HF) in China. However, little is known of the underlying mechanism of LGZGD.

AIM OF THE STUDY

The aim of this work was to investigate the therapeutic mechanism of LGZGD on HF treatment based on an integration of the serum metabolomics and network analysis.

MATERIALS AND METHODS

HF model mice were established by intraperitoneal injecting of doxorubicin. Body weight, echocardiography, biochemical assay and hematoxylin and eosin staining experiments were used to evaluate the efficacy of LGZGD. A metabolomics approach based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was performed to analyze the serum biomarkers from model group, control group and LGZGD-treatment group. Principle component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA) were utilized to identify differences of metabolic profiles in mice among the three groups. The network of "gene-enzyme-metabolite" was built to investigate the possible mechanism of LGZGD from the systematic perspective.

RESULTS

54 metabolites, which showed a significantly restoring trend from HF to normal condition, were regarded as potential biomarkers of LGZGD treatment. The most critical pathway was glycerophospholipid metabolism and arachidonic acid metabolism. According to the results of network analysis, 8 biomarkers were regarded as hub metabolites, which meant these metabolites may have a major relationship with the LGZGD therapeutic effects for the HF. 8 enzymes and 29 genes in the network were considered as potential targets of LGZGD treatment.

CONCLUSIONS

By integrated serum metabolomic and network analysis, we found that LGZGD might retard the pathological process of HF by regulating the disturbed metabolic pathways and the relative enzymes, which may be potential mechanism for LGZGD in the treatment of HF.

LC-MS-based serum fingerprinting reveals significant dysregulation of phospholipids in chronic heart failure

Cardiac and extracardiac lipid metabolism is known to be significantly altered in the course of the heart failure with reduced ejection fraction (HF-REF), however the precise mechanisms are not fully elucidated. The aim of the study was to use of untargeted metabolomics to identify and validate changes in the blood metabolites profile, occurring as a result of HF-REF development. The analyses were performed first in the derivation set (36 chronic HF-REF patients and 19 controls without the disease) and repeated in validation cohort (31 chronic HF-REF patients and 20 controls). Independent analyses of both sets revealed statistically significant decline in intensities of phosphatidylcholine (PC): 34:4 and 36:5, lysophosphatidylcholine (lyso-PC): 14:0, 15:0, 18:0, 18:2, 20:3, lysophosphatidylethanolamine (lyso-PE): 18:1 and 18:2 in chronic HF-REF patients. More symptomatic patients and those with ischaemic etiology of HF-REF presented greater deficit in phospholipids (PLs) intensities. The decrease of identified PLs intensities (as compared to controls) correlated with decreased serum cholesterol level, impaired renal function, reduced exercise capacity, enhanced ventilatory response and metabolic parameters associated with altered fatty acids oxidation. In multiple regression analysis PLs deficit was significantly associated with age, carnitines serum intensity, renal function, uric acid, cholesterol level. In conclusion, HF-REF is associated with significant disturbances in phospholipids metabolism. Greater reduction in serum intensities of particular identified PLs is associated with older age, worse clinical condition, impaired oxidative muscle metabolism and enhanced catabolic status.

Lipoprotein-associated phospholipase A2, and subsequent cardiovascular events and mortality among patients with coronary heart disease

OBJECTIVE

The objective of this study is to evaluate the relevance of Lp-PLA₂ to risk prediction among coronary heart disease (CHD) patients.

METHODS

Lp-PLA₂ activity was measured in 2538 CHD patients included in the Bezafibrate Infarction Prevention (BIP) study.

RESULTS

Adjusting for patient characteristics and traditional risk factors, 1 standard deviation of Lp-PLA₂ was associated with a hazard ratio (HR) of 1.12 (95% confidence interval (CI): 1.00-1.25) for mortality and 1.03 (0.93-1.14) for cardiovascular events. Lp-PLA₂ did not significantly improve model discrimination, or calibration nor result in noteworthy reclassification.

CONCLUSIONS

Our results do not support added value of Lp-PLA₂ for predicting cardiovascular events or mortality among CHD patients beyond traditional risk factor.

Platelet activating factor in heart failure: potential role in disease progression and novel target for therapy

Heart failure (HF) is a complex syndrome with cardiac, renal, neurohormonal and sympathetic nervous system's manifestations, the pathogenesis of which among others is connected to inflammation. PAF has local and systemic effects pertaining to HF progression since it causes a negative inotropic effect, it induces arrhythmias, it induces apoptosis and it is involved in inflammation and atherosclerosis. In the present review the role of PAF in HF will be thoroughly presented along with the relevant data on PAF enzymes and the potential role of PAF metabolic circuit as a novel pharmacological target.

Clinical adoption of prognostic biomarkers: the case for heart failure

The recent explosion of scientific knowledge and technological progress has led to the discovery of a large array of circulating molecules commonly referred to as biomarkers. Biomarkers in heart failure (HF) research have been used to provide pathophysiologic insights, aid in establishing the diagnosis, refine prognosis, guide management, and target treatment. However, beyond diagnostic applications of natriuretic peptides, there are currently few widely recognized applications for biomarkers in HF. This represents a remarkable discordance considering the number of molecules that have been shown to correlate with outcomes, refine risk prediction, or track disease severity in HF in the past decade. In this article, we use a broad framework proposed for cardiovascular risk markers to summarize the current state of biomarker development for patients with HF. We use this framework to identify the challenges of biomarker adoption for risk prediction, disease management, and treatment selection for HF and suggest considerations for future research.

Baseline and 6-Week follow-up levels of PAF and activity of its metabolic enzymes in patients with heart failure and healthy volunteers--a pilot study

This study aimed at evaluating the changes in platelet-activating factor (PAF) and its metabolic enzymes over a 6-week follow-up period in patients with newly diagnosed heart failure ([HF] n = 12) compared with age-, sex-, and BMI-matched apparently healthy volunteers (n = 10). The PAF, its key biosynthetic enzymes (lyso-PAF acetyltransferase [lyso-PAF-AT] and dithiothreitol [DTT]-insensitive CDP choline: 1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase [PAF-CPT]), and its catabolic isoenzymes (PAF-acetylhydrolase [PAF-AH] and lipoprotein-associated phospholipase A2 [Lp-PLA2]) were measured in serum and leukocytes of participants. At baseline, patients with HF had lower median activities of lyso-PAF-AT (P < .001) and PAF-CPT (P = .07) in parallel with PAF levels (P = .05) and higher activities of PAF-AH (P = .02) and Lp-PLA2 (P < .001) than controls. At follow-up, PAF-CPT and PAF levels marginally increased (P = .1), lyso-PAF-AT (P < .001) remained downregulated, while PAF-AH (P = .004) and Lp-PLA2 (P < .001) remained elevated compared with the controls. Newly diagnosed patients with HF under drug treatment have an affected profile of PAF biosynthetic enzymes and especially lyso-PAF-AT.

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.

Lipoprotein-associated phospholipase A₂ activity and mass in relation to vascular disease and nonvascular mortality

OBJECTIVES

To assess whether associations of circulating lipoprotein-associated phospholipase A₂ (Lp-PLA₂) with vascular disease are independent of other risk factors.

METHODS

Lp-PLA₂ activity and mass, lipids and other characteristics were measured at baseline in 19,037 individuals at high risk of vascular disease in a randomized trial of simvastatin with 5-year average follow-up.

RESULTS

Lp-PLA₂ activity and mass were correlated with each other (r = 0.56), lipids and other vascular risk factors. The moderate association of Lp-PLA₂ activity with occlusive coronary events (n = 2531) in analyses adjusted for nonlipid factors (hazard ratio per 1 SD [HR] 1.11, 95% CI 1.06-1.15) became nonsignificant after further adjustment for apolipoproteins (HR 1.02, 0.97-1.06). Such adjustment also attenuated HRs with Lp-PLA₂ mass from 1.08 (1.03-1.12) to 1.05 (1.01-1.09). By contrast, the HR with apolipoprotein-B100 of 1.15 (1.10-1.19) was only slightly attenuated to 1.14 (1.09-1.19) after further adjustment for apolipoprotein A₁ and Lp-PLA₂. Age- and sex-adjusted HRs for other cardiac events (n = 1007) with either Lp-PLA₂ activity or mass were about 1.20, but HRs reduced after adjustment for nonlipid factors (activity: 1.11, 1.04-1.18; mass: 1.08, 1.02-1.15). Adjusted HRs for ischaemic stroke (n = 900) were weak and nonsignificant and for nonvascular mortality (n = 1040) were 1.01 (0.94-1.09) with activity and 1.12 (1.05-1.19) with mass. Simvastatin reduced Lp-PLA₂ levels by about one-quarter, but simvastatin's vascular protection did not vary with baseline Lp-PLA₂ concentration.

CONCLUSIONS

Associations of Lp-PLA₂ with occlusive coronary events depend considerably on lipid levels, whereas those with other cardiac events appear to reflect confounding from cardiovascular medication and prior vascular disease.

Lipoprotein-associated phospholipase A2 as a biomarker of coronary heart disease and a therapeutic target

PURPOSE OF REVIEW

Lipoprotein-associated phospholipase A2 (Lp PLA2) is postulated to occupy a key position in the pathogenic sequence leading to formation of complex atherosclerotic lesions. This study reviews evidence supporting its role as a biomarker of vascular disease and as a possible therapeutic target.

RECENT FINDINGS

Evidence continues to build supporting the usefulness of Lp PLA2 as a predictor of coronary events in the general population and in those with established coronary heart disease. Elevated Lp PLA2 is also associated with stroke and heart failure. The crystal structure of Lp PLA2 is now available and offers insight into the links between structure, function and atherogenic properties. Recently completed studies on the efficacy of darapladib, a specific Lp PLA2 inhibitor, show beneficial changes in plaque morphology in animal models and in humans.

SUMMARY

Lp PLA2 is gaining acceptance as a useful biomarker of chronic inflammation and as a predictor of vascular disease. Early results with darapladib offer promise, but not definitive proof, of a potential role for Lp PLA2 inhibition in coronary heart disease prevention.

Lipoprotein-associated phospholipase A(2) and risk of congestive heart failure in older adults: the Cardiovascular Health Study

BACKGROUND

Inflammation may be a causative factor in congestive heart failure (CHF). Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an inflammation marker associated with vascular risk. One previous study showed an association of Lp-PLA(2) activity with CHF risk, but there were only 94 CHF cases and Lp-PLA(2) antigen, which is available clinically in the United States, was not measured.

METHODS AND RESULTS

We measured baseline Lp-PLA(2) antigen and activity in 3991 men and women without baseline CHF or cardiovascular disease who were participating in the Cardiovascular Health Study, a prospective observational study of adults 65 years or older. Cox proportional hazards models adjusted for age, sex, clinic site, race, low-density and high-density lipoprotein cholesterol, body mass index, systolic and diastolic blood pressure, hypertension, smoking status, pack-years, and diabetes were used to calculate hazard ratios and 95% CIs for incident CHF. Further models adjusted for coronary disease events during follow-up and C-reactive protein. Eight hundred twenty-nine participants developed CHF during 12.1 years. Adjusted hazard ratios for CHF with Lp-PLA(2) in the fourth compared with the first quartile were 1.44 (95% CI, 1.16 to 1.79) for Lp-PLA(2) antigen and 1.06 (95% CI, 0.84 to 1.32) for activity. Adjustment for incident coronary disease attenuated the hazard ratio for Lp-PLA(2) antigen to 1.26 (95% CI, 1.02 to 1.57), adjustment for C-reactive protein had minimal impact.

CONCLUSIONS

Lp-PLA(2) antigen was associated with risk of future CHF in older people, independent of CHF and coronary risk factors, and partly mediated by coronary disease events. Further clinical and basic research is needed to better understand the role of Lp-PLA(2) in CHF.