The effect of nine common polymorphisms in coagulation factor genes (F2, F5, F7, F12 and F13) on the effectiveness of statins: the GenHAT study

Gene networks and pathways for plasma lipid traits via multitissue multiomics systems analysis

Genome-wide association studies (GWASs) have implicated ∼380 genetic loci for plasma lipid regulation. However, these loci only explain 17-27% of the trait variance, and a comprehensive understanding of the molecular mechanisms has not been achieved. In this study, we utilized an integrative genomics approach leveraging diverse genomic data from human populations to investigate whether genetic variants associated with various plasma lipid traits, namely, total cholesterol, high and low density lipoprotein cholesterol (HDL and LDL), and triglycerides, from GWASs were concentrated on specific parts of tissue-specific gene regulatory networks. In addition to the expected lipid metabolism pathways, gene subnetworks involved in "interferon signaling," "autoimmune/immune activation," "visual transduction," and "protein catabolism" were significantly associated with all lipid traits. In addition, we detected trait-specific subnetworks, including cadherin-associated subnetworks for LDL; glutathione metabolism for HDL; valine, leucine, and isoleucine biosynthesis for total cholesterol; and insulin signaling and complement pathways for triglyceride. Finally, by using gene-gene relations revealed by tissue-specific gene regulatory networks, we detected both known (e.g., APOH, APOA4, and ABCA1) and novel (e.g., F2 in adipose tissue) key regulator genes in these lipid-associated subnetworks. Knockdown of the F2 gene (coagulation factor II, thrombin) in 3T3-L1 and C3H10T1/2 adipocytes altered gene expression of Abcb11, Apoa5, Apof, Fabp1, Lipc, and Cd36; reduced intracellular adipocyte lipid content; and increased extracellular lipid content, supporting a link between adipose thrombin and lipid regulation. Our results shed light on the complex mechanisms underlying lipid metabolism and highlight potential novel targets for lipid regulation and lipid-associated diseases.

Seventeen years of statin pharmacogenetics: a systematic review

AIM

We evaluated the evidence of pharmacogenetic associations with statins in a systematic review.

METHODS

Two separate outcomes were considered of interest: modification of low-density lipoprotein cholesterol (LDL-C) response and modification of risk for cardiovascular events.

RESULTS

In candidate gene studies, 141 loci were claimed to be associated with LDL-C response. Only 5% of these associations were positively replicated. In addition, six genome-wide association studies of LDL-C response identified common SNPs in APOE, LPA, SLCO1B1, SORT1 and ABCG2 at genome-wide significance. None of the investigated SNPs consistently affected the risk reduction for cardiovascular events.

CONCLUSION

Only five genetic loci were consistently associated with LDL-C response. However, as effect sizes are modest, there is no evidence for the value of genetic testing in clinical practice.

Genetic risk, coronary heart disease events, and the clinical benefit of statin therapy: an analysis of primary and secondary prevention trials

BACKGROUND

Genetic variants have been associated with the risk of coronary heart disease. In this study, we tested whether or not a composite of these variants could ascertain the risk of both incident and recurrent coronary heart disease events and identify those individuals who derive greater clinical benefit from statin therapy.

METHODS

A community-based cohort study (the Malmo Diet and Cancer Study) and four randomised controlled trials of both primary prevention (JUPITER and ASCOT) and secondary prevention (CARE and PROVE IT-TIMI 22) with statin therapy, comprising a total of 48,421 individuals and 3477 events, were included in these analyses. We studied the association of a genetic risk score based on 27 genetic variants with incident or recurrent coronary heart disease, adjusting for traditional clinical risk factors. We then investigated the relative and absolute risk reductions in coronary heart disease events with statin therapy stratified by genetic risk. We combined data from the different studies using a meta-analysis.

FINDINGS

When individuals were divided into low (quintile 1), intermediate (quintiles 2-4), and high (quintile 5) genetic risk categories, a significant gradient in risk for incident or recurrent coronary heart disease was shown. Compared with the low genetic risk category, the multivariable-adjusted hazard ratio for coronary heart disease for the intermediate genetic risk category was 1·34 (95% CI 1·22-1·47, p<0·0001) and that for the high genetic risk category was 1·72 (1·55-1·92, p<0·0001). In terms of the benefit of statin therapy in the four randomised trials, we noted a significant gradient (p=0·0277) of increasing relative risk reductions across the low (13%), intermediate (29%), and high (48%) genetic risk categories. Similarly, we noted greater absolute risk reductions in those individuals in higher genetic risk categories (p=0·0101), resulting in a roughly threefold decrease in the number needed to treat to prevent one coronary heart disease event in the primary prevention trials. Specifically, in the primary prevention trials, the number needed to treat to prevent one such event in 10 years was 66 in people at low genetic risk, 42 in those at intermediate genetic risk, and 25 in those at high genetic risk in JUPITER, and 57, 47, and 20, respectively, in ASCOT.

INTERPRETATION

A genetic risk score identified individuals at increased risk for both incident and recurrent coronary heart disease events. People with the highest burden of genetic risk derived the largest relative and absolute clinical benefit from statin therapy.

FUNDING

National Institutes of Health.

Effect of CETP polymorphism on atorvastatin lipid-regulating effect and clinical prognosis of patients with coronary heart disease

Background

The aim of this study was to investigate the influence of genetic polymorphism of cholesteryl ester transfer protein (CETP) gene polymorphism −629C/A on the therapeutic effect of atorvastatin and clinical outcome in Han Chinese patients with coronary heart disease (CHD).

Material/Methods

From October 2011 to December 2012, 348 patients with angiographically confirmed CHD were recruited. CETP gene polymorphism was determined by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) method. Serum level of CETP was determined with enzyme-1inked immunosorbent assay (ELISA). Lipid 1evel in all patients was determined at baseline and after 12 months of treatment with 20 mg/d of atorvastatin. All the patients were followed-up at least 12 months. Major adverse cardiac events, including death, non-fatal infarction, revascularization, and stroke (MACE), were recorded.

Results

The frequency of the −629A allele was 0.412. Compared with CC or CA genotypes, individuals with AA genotype had lower CETP levels (P=0.026) and higher high-density lipoprotein cholesterol (HDL-C) levels (P=0.035). After 12 months of atorvastatin therapy, carriers with CC genotype had greater reduction of low-density lipoprotein cholesterol (LDL-C) (P<0.001), reduced LP (a) (P=0.005), and elevated HDL-C (P=0.045) compared with CA or AA genotypes. The incidence of MACE after a mean follow-up of 17.3±5.2 months was 8.8%. The cumulative MACE-free survival rates were 90.1%, 85.2%, and 71.1% for CC, CA, and AA genotypes, respectively.

Conclusions

Our results suggest that the AA variant of the −629A allele of CETP gene had higher HDL-C levels and reduced CETP levels, but patients with CC genotype appeared to have benefited more from statin therapy with reduction in LDL-C and LP (a) levels. Long-term clinical prognosis was, however, not affected by the 3 genotypes.

Haemostaseome-associated SNPs: has the thrombotic phenotype a greater influence than ethnicity? GMT study from Aquitaine including Basque individuals

The Genetic Markers for Thrombosis (GMT) study compared the relative influence of ethnicity and thrombotic phenotype regarding the distribution of SNPs implicated in haemostasis pathophysiology ("haemostaseome"). We assessed 384 SNPs in three groups, each of 480 subjects: 1) general population of Aquitaine region (Southwestern France) used as control; 2) patients with venous thromboembolism from the same area; and 3) autochthonous Basques, a genetic isolate, who demonstrate unusual characteristics regarding the coagulation system. This study sought to evaluate i) the value of looking for a large number of genes in order to identify new genetic markers of thrombosis, ii) the value of investigating low risk factors and potential preferential associations, iii) the impact of ethnicity on the characterisation of markers for thrombosis. We did not detect any previously unrecognised SNP significantly associated with thrombosis risk or any preferential associations of low-risk factors in patients with thrombosis. The sum of ϰ² values for our 110 significant SNPs demonstrated a smaller genetic distance between patients and controls (321 cumulated ϰ² value) than between Basques and controls (1,570 cumulated ϰ² value). Hence, our study confirms the genetic particularity of Basques especially regarding a significantly lower expression of the non-O blood group (p< 0.0004). This is mitigated by a higher prevalence of factor II Leiden (p< 0.02) while factor V Leiden prevalence does not differ. Numerous other differences covering a wide range of proteins of the haemostaseome may result in an overall different genetic risk for venous thromboembolism.

Application of routine electronic health record databases for pharmacogenetic research

Inter-individual variability in drug responses is a common problem in pharmacotherapy. Several factors (non-genetic and genetic) influence drug responses in patients. When aiming to obtain an optimal benefit-risk ratio of medicines and with the emergence of genotyping technology, pharmacogenetic studies are important for providing recommendations on drug treatments. Advances in electronic healthcare information systems can contribute to increasing the quality and efficiency of such studies. This review describes the definition of pharmacogenetics, gene selection and study design for pharmacogenetic research. It also summarizes the potential of linking pharmacoepidemiology and pharmacogenetics (along with its strengths and limitations) and provides examples of pharmacogenetic studies utilizing electronic health record databases.

Pharmacogenomic association of nonsynonymous SNPs in SIGLEC12, A1BG, and the selectin region and cardiovascular outcomes

We sought to identify novel pharmacogenetic markers associated with cardiovascular outcomes in patients with hypertension on antihypertensive therapy. We genotyped a 1:4 case:control cohort (n=1345) on the Illumina HumanCVD Beadchip from the INternational VErapamil SR-Trandolapril STudy (INVEST), where participants were randomized to a β-blocker strategy or a calcium channel blocker strategy. Genome-spanning single nucleotide polymorphism (SNP)×treatment interaction analyses of nonsynonymous SNPs were conducted in white and Hispanic race/ethnic groups. Top hits from whites were tested in Hispanics for consistency. A genetic risk score was constructed from the top 3 signals and tested in the Nordic Diltiazem study. SIGLEC12 rs16982743 and A1BG rs893184 had a significant interaction with treatment strategy for adverse cardiovascular outcomes (INVEST whites and Hispanics combined interaction P=0.0038 and 0.0036, respectively). A genetic risk score, including rs16982743, rs893184, and rs4525 in F5, was significantly associated with treatment-related adverse cardiovascular outcomes in whites and Hispanics from the INVEST study and in the Nordic Diltiazem study (meta-analysis interaction P=2.39×10(-5)). In patients with a genetic risk score of 0 or 1, calcium channel blocker treatment was associated with lower risk (odds ratio [95% confidence interval]=0.60 [0.42-0.86]), and in those with a genetic risk score of 2 to 3, calcium channel blocker treatment was associated with higher risk (odds ratio [95% confidence interval]=1.31 [1.08-1.59]). These results suggest that cardiovascular outcomes may differ based on SIGLEC12, A1BG, F5 genotypes, and antihypertensive treatment strategy. These specific genetic associations and our risk score provide insight into a potential approach to personalized antihypertensive treatment selection.

Statins personalized

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitor medications, commonly referred to as statins, are among the most widely prescribed medications. Variation in individual response to statins concerning low-density lipoprotein cholesterol reduction, clinical event benefit, and side effects has been observed. Some of this variability is attributed to demographic and environmental issues, chief of which is compliance. A large portion of the individual response to statin therapy is attributed to single nucleotide polymorphisms that have recently been elucidated, several of which seem to have clinical utility.

Coagulation factor XIII-A Val34Leu polymorphism and the risk of coronary artery disease and myocardial infarction in a Chinese Han population

There are controversial data regarding the impact of coagulation factor XIII A subunit (FXIII-A) Val34Leu polymorphism in the pathogeneric of coronary artery disease (CAD) and myocardial infarction (MI). Assuming this genetic factor is associated with the thrombotic process, we explored the role of FXIII-A Val34Leu in CAD and MI in a Chinese Han population. We recruited 195 consecutive patients with CAD confirmed by coronary angiography as well as a group of 203 controls. Factor XIII A Val34Leu polymorphism was determined through polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis. We did not find the Leu/Leu genotype in patients with CAD or controls. No significant difference in Val34Leu gene polymorphism distribution was found between patients with CAD and the controls (P = .923). Subgroup analysis according to the history of MI showed the heterozygote Val/Leu genotype was associated with a significantly decreased risk of MI (P = .005; adjusted odds ratio [OR] = 1.75; 95% confidence interval [CI] = 1.28-2.25). Furthermore, our study displayed that the frequency of the Leu34 allele in a Chinese Han population was lower than that in Caucasian populations (2.5 vs 20.4%-28.3%). Our preliminary data indicate that the FXIII-A Leu34 allele may contribute to a protective effect against the development of MI. There is a low prevalence of the Leu34 allele in Han Chinese compared to Caucasians.

Genetic determinants of response to statins

In developed countries, cardiovascular disease is one of the leading causes of death. Statins are abundantly prescribed to reduce the risk of coronary artery disease by lowering cholesterol. Genetic factors are thought to be partly responsible for the interindividual variation in the response to statins. This article reviews the most important studies conducted on pharmacogenetics of statins. Currently, there is no evidence to advocate pharmacogenetic testing before initiating therapy.