Secretory phospholipase A(2)-IIA and cardiovascular disease: a mendelian randomization study

OBJECTIVES

This study sought to investigate the role of secretory phospholipase A2 (sPLA2)-IIA in cardiovascular disease.

BACKGROUND

Higher circulating levels of sPLA2-IIA mass or sPLA2 enzyme activity have been associated with increased risk of cardiovascular events. However, it is not clear if this association is causal. A recent phase III clinical trial of an sPLA2 inhibitor (varespladib) was stopped prematurely for lack of efficacy.

METHODS

We conducted a Mendelian randomization meta-analysis of 19 general population studies (8,021 incident, 7,513 prevalent major vascular events [MVE] in 74,683 individuals) and 10 acute coronary syndrome (ACS) cohorts (2,520 recurrent MVE in 18,355 individuals) using rs11573156, a variant in PLA2G2A encoding the sPLA2-IIA isoenzyme, as an instrumental variable.

RESULTS

PLA2G2A rs11573156 C allele associated with lower circulating sPLA2-IIA mass (38% to 44%) and sPLA2 enzyme activity (3% to 23%) per C allele. The odds ratio (OR) for MVE per rs11573156 C allele was 1.02 (95% confidence interval [CI]: 0.98 to 1.06) in general populations and 0.96 (95% CI: 0.90 to 1.03) in ACS cohorts. In the general population studies, the OR derived from the genetic instrumental variable analysis for MVE for a 1-log unit lower sPLA2-IIA mass was 1.04 (95% CI: 0.96 to 1.13), and differed from the non-genetic observational estimate (OR: 0.69; 95% CI: 0.61 to 0.79). In the ACS cohorts, both the genetic instrumental variable and observational ORs showed a null association with MVE. Instrumental variable analysis failed to show associations between sPLA2 enzyme activity and MVE.

CONCLUSIONS

Reducing sPLA2-IIA mass is unlikely to be a useful therapeutic goal for preventing cardiovascular events.

Pathway analysis using genome-wide association study data for coronary restenosis--a potential role for the PARVB gene

Background

Coronary restenosis after percutaneous coronary intervention (PCI) still remains a significant limitation of the procedure. The causative mechanisms of restenosis have not yet been fully identified. The goal of the current study was to perform gene-set analysis of biological pathways related to inflammation, proliferation, vascular function and transcriptional regulation on coronary restenosis to identify novel genes and pathways related to this condition.

Methods

The GENetic DEterminants of Restenosis (GENDER) databank contains genotypic data of 556,099SNPs of 295 cases with restenosis and 571 matched controls. Fifty-four pathways, related to known restenosis-related processes, were selected. Gene-set analysis was performed using PLINK, GRASS and ALIGATOR software. Pathways with a p<0.01 were fine-mapped and significantly associated SNPs were analyzed in an independent replication cohort.

Results

Six pathways (cell-extracellular matrix (ECM) interactions pathway, IL2 signaling pathway, IL6 signaling pathway, platelet derived growth factor pathway, vitamin D receptor pathway and the mitochondria pathway) were significantly associated in one or two of the software packages. Two SNPs in the cell-ECM interactions pathway were replicated in an independent restenosis cohort. No replication was obtained for the other pathways.

Conclusion

With these results we demonstrate a potential role of the cell-ECM interactions pathway in the development of coronary restenosis. These findings contribute to the increasing knowledge of the genetic etiology of restenosis formation and could serve as a hypothesis-generating effort for further functional studies.

Candidate gene analysis of arteriovenous fistula failure in hemodialysis patients

BACKGROUND AND OBJECTIVES

Arteriovenous fistula (AVF) failure remains an important cause of morbidity in hemodialysis patients. The exact underlying mechanisms responsible for AVF failure are unknown but processes like proliferation, inflammation, vascular remodeling, and thrombosis are thought to be involved. The current objective was to investigate the association between AVF failure and single nucleotide polymorphisms (SNPs) in genes related to these pathophysiologic processes in a large population of incident hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 479 incident hemodialysis patients were included between January 1997 and April 2004. Follow-up lasted 2 years or until AVF failure, defined as surgery, percutaneous endovascular intervention, or abandonment of the vascular access. Forty-three SNPs in 26 genes, related to proliferation, inflammation, endothelial function, vascular remodeling, coagulation, and calcium/phosphate metabolism, were genotyped. Relations were analyzed using Cox regression analysis.

RESULTS

In total, 207 (43.2%) patients developed AVF failure. After adjustment, two SNPs were significantly associated with an increased risk of AVF failure. The hazard ratio (95% confidence interval) of LRP1 rs1466535 was 1.75 (1.15 to 2.66) and patients with factor V Leiden had a hazard ratio of 2.54 (1.41 to 4.56) to develop AVF failure. The other SNPs were not associated with AVF failure.

CONCLUSIONS

In this large cohort of hemodialysis patients, only 2 of the 43 candidate SNPs were associated with an increased risk of AVF failure. Whether other factors, like local hemodynamic circumstances, are more important or other SNPs play a role in AVF failure remains to be elucidated.

Pharmacogenetics of statins: achievements, whole-genome analyses and future perspectives

Statins are the most commonly prescribed class of drug worldwide and therapy is highly effective in reducing low-density lipoprotein cholesterol levels and cardiovascular events. However, there is large variability in clinical response to statin treatment. Recent research provides evidence that genetic variation contributes to this variable response to statin treatment. Until recently, pharmacogenetic studies have used mainly candidate gene approaches to investigate these effects. Since candidate gene studies explain only a small part of the observed variation and results have often been inconsistent, genome-wide association (GWA) studies may be a better approach. In this paper the most important candidate gene studies and the first published GWA studies assessing statin response are discussed. Moreover, we describe the PHASE study, an EU-funded GWA study that will investigate the genetic variation responsible for the variation in response to pravastatin in a large randomized clinical trial.

Restenosis after PCI. Part 1: pathophysiology and risk factors

Restenosis is a complex disease for which the pathophysiological mechanisms have not yet been fully elucidated, but are thought to include inflammation, proliferation, and matrix remodeling. Over the years, many predictive clinical, biological, (epi)genetic, lesion-related, and procedural risk factors for restenosis have been identified. These factors are not only useful in risk stratification of patients, they also contribute to our understanding of this condition. Furthermore, these factors provide evidence on which to base treatment tailored to the individual and aid in the development of novel therapeutic modalities. In this Review, we will evaluate the available evidence on the pathophysiological mechanisms of restenosis and provide an overview of the various risk factors, together with the possible clinical application of this knowledge.

A genome-wide association study identifies a region at chromosome 12 as a potential susceptibility locus for restenosis after percutaneous coronary intervention

Percutaneous coronary intervention (PCI) has become an effective therapy to treat obstructive coronary artery diseases (CAD). However, one of the major drawbacks of PCI is the occurrence of restenosis in 5-25% of all initially treated patients. Restenosis is defined as the re-narrowing of the lumen of the blood vessel, resulting in renewed symptoms and the need for repeated intervention. To identify genetic variants that are associated with restenosis, a genome-wide association study (GWAS) was conducted in 295 patients who developed restenosis (cases) and 571 who did not (controls) from the GENetic Determinants of Restenosis (GENDER) study. Analysis of ~550 000 single nucleotide polymorphisms (SNPs) in GENDER was followed by a replication phase in three independent case-control populations (533 cases and 3067 controls). A potential susceptibility locus for restenosis at chromosome 12, including rs10861032 (P(combined) = 1.11 × 10(-7)) and rs9804922 (P(combined) = 1.45 × 10(-6)), was identified in the GWAS and replication phase. In addition, both SNPs were also associated with coronary events (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023) in a trial based cohort set of elderly patients with (enhanced risk of) CAD (PROSPER) and all-cause mortality in PROSPER (rs10861032, P(additive) = 0.007; rs9804922, P(additive) = 0.013) and GENDER (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023). Further analysis suggests that this locus could be involved in regulatory functions.

A systematic review on pharmacogenetics in cardiovascular disease: is it ready for clinical application?

Pharmacogenetics is the search for heritable genetic polymorphisms that influence responses to drug therapy. The most important application of pharmacogenetics is to guide choosing agents with the greatest potential of efficacy and smallest risk of adverse drug reactions. Many studies focusing on drug-gene interactions have been published in recent years, some of which led to adaptation of FDA recommendations, indicating that we are on the verge of the clinical application of genetic information in drug therapy. This systematic review provides a comprehensive overview of the current knowledge on pharmacogenetics of all major drug classes currently used in the treatment of cardiovascular diseases.

Factor VII Activating Protease Polymorphism (G534E) Is Associated with Increased Risk for Stroke and Mortality

Introduction. The FSAP-Marburg I polymorphism (1704G > A), which reduces FSAP activity, is associated with late complications of carotid stenosis in humans. Therefore, this study examines the influence of the Marburg I polymorphism and the closely linked Marburg II polymorphism (1280G > C) on various cardiovascular outcomes in two large independent study populations. Methods. The two Marburg polymorphisms in the HABP2 gene encoding FSAP were genotyped in a large population of elderly patients at risk for vascular disease (the PROSPER-study, n = 5804) and in a study population treated with a percutaneous coronary intervention (the GENDER-study, n = 3104). Results. In the PROSPER study, the Marburg I polymorphism was associated with an increased risk of clinical stroke (HR: 1.60, 95% CI: 1.13-2.28) and all-cause mortality (HR: 1.33, 95% CI: 1.04-1.71). In the GENDER study carriers of this variant seemed at lower risk of developing restenosis (HR: 0.59, 95% CI: 0.34-1.01). The Marburg II polymorphism showed similar but weaker results. Conclusion. The increase in stroke risk in Marburg I carriers could be due to differential effects on smooth muscle cells and on matrix metalloproteinases, thereby influencing plaque stability. The possible protective effect on restenosis could be the result of reduced activation of zymogens, which are involved in hemostasis and matrix remodeling.

Matrix metalloproteinases 2 and 3 gene polymorphisms and the risk of target vessel revascularization after percutaneous coronary intervention: Is there still room for determining genetic variation of MMPs for assessment of an increased risk of restenosis?

OBJECTIVE

Mixed results have been reported of matrix metalloproteinases (MMP) and their association with restenosis after percutaneous coronary intervention (PCI). The current study examines whether multiple single nucleotide polymorphisms (SNPs), covering the full genomic region of MMP2 and MMP3, were associated with restenosis in the GENDER study population.

METHODS AND RESULTS

The GENetic DEterminants of Restenosis (GENDER) study enrolled 3104 consecutive patients after successful PCI. The primary endpoint was clinical restenosis, defined as target vessel revascularization (TVR), occurring in 9.8% of the patients. From the Hapmap database, 19 polymorphisms of MMP2 and 11 of MMP3 were selected. Furthermore, in a subpopulation, a genome-wide association analysis (GWA) was performed. No significant association was found with any of the investigated SNPs, including the previously reported 5A/6A polymorphism (rs3025058), with regard to TVR using single SNP analysis or haplotype analysis.

CONCLUSION

We found no significant association of MMP2 or MMP3 with TVR with this SNP-broad gene approach. Although we did not test all the known polymorphisms of these genes, using tagging analyses we examined those SNPs covering all known haplotypes of MMP2 and MMP3 to conclude that these genes do not correlate with a genetic risk of coronary restenosis after successful PCI.