The NLRP3 Genetic Variant (rs10754555) Reduces the Risk of Adverse Outcome in Middle-Aged Patients with Chronic Coronary Syndrome.

Background: Inflammation is central in development of cardiovascular disease (CVD). Aberrant function of the Nod-Like Receptor Protein 3 (NLRP3) inflammasome, a central mediator in the proinflammatory response, has been associated with atherosclerosis. The influence of genetic determinants on this inflammatory pathway and its downstream effects is less known. We aimed to investigate the frequency of a single NLRP3 gene variant according to clinical outcome in CVD and its influence on NLRP3-related markers. Methods: In this observational study, we included 1001 patients with chronic coronary syndrome. Blood samples were drawn at inclusion, including whole-blood and PAXgene tubes for DNA and RNA isolation, respectively. Allelic discrimination of the NLRP3 single nucleotide polymorphism rs10754555 was performed; and gene expression of NLRP3, Toll-Like Receptor 4, Interleukin- (IL-) 1ß, and IL-18 was relatively quantified, both methods by RT-PCR. Circulating IL-6, high-sensitivity (hs) C-reactive protein, IL-18, and IL-12 were measured by enzyme-like immunosorbent assays. Clinical endpoints during 2 years (n = 106) were a composite of unstable angina pectoris, myocardial infarction, nonhemorrhagic stroke, and death. Results: Minor allele frequency of the NLRP3 variant was 0.36. In all, no association of the NLRP3 variant with clinical subgroups or outcome was found, neither any significant influence on the genes' mRNA expression or circulating protein. However, in subjects < 56 years (25 percentile), the variant G-allele is associated with significant lower risk of suffering a composite event (OR = 0.43 (95% CI 0.19, 0.97), p = 0.043, adjusted). In the same age group, the NLRP3 gene was accordingly downregulated in G-allele carriers vs. noncarriers, and circulating IL12 was significantly reduced (p < 0.05, both). In subjects > 56 years, no significant effect of the variant was observed. Conclusion: The age-related reduced risk of composite endpoint in rs10754555 G-allele carriers accompanied by diminished NLRP3 mRNA expression is hypothesis generating and needs to be further explored. The study is registered at http://www.clinicaltrials.gov, with identification number NCT00222261.

Genetic variation, gene-expression and circulating levels of matrix metalloproteinase-9 in patients with stable coronary artery disease.

BACKGROUND: Mediators involved in atherosclerosis and plaque rupture may have importance as risk markers for coronary artery disease (CAD). We have investigated the influence of matrix metalloproteinase (MMP)-9 genetic variations on gene- and protein expression in stable CAD patients. METHODS: The promoter -1562C/T and exon 6 R279Q A/G polymorphisms were determined in 1001 patients with angiographically verified stable CAD and in 204 healthy controls. Genotype and gene-expression were determined by real-time PCR. Serum levels of MMP-9 and its inhibitor TIMP-1were measured immunologically and by zymography (MMP-9 activity). RESULTS: None of the polymorphisms associated with the presence of CAD, myocardial infarction or type 2 diabetes, whereas the variant allele of the R279Q polymorphism associated with hypertension (adjusted p=0.015). The T- and G alleles associated with lower and higher mRNA levels, respectively (p<0.005 both), also shown in an experimental ex-vivo LPS stimulated model. T-allele carriers had higher concentrations of MMP-9 (adjusted p=0.032) and the GG genotype induced lower MMP-9 gelatinolytic activity (p=0.01). Higher MMP-9 gene-expression and TIMP-1 levels were observed in patients with previous myocardial infarction, the latter also was elevated in diabetics (<0.05, all). CONCLUSION: The investigated MMP-9 polymorphisms influenced gene- and protein expression differently and the R279Q polymorphism associated significantly with hypertension.

The influence of CYP 2C19*2 polymorphism on platelet function testing during single antiplatelet treatment with clopidogrel.

BACKGROUND: Different platelet function tests can be used to evaluate the degree of achieved platelet inhibition in patients treated with clopidogrel. The presence of CYP 2C19*2 polymorphism can reduce the formation of the active metabolite of clopidogrel, resulting in less platelet inhibition. PATIENTS AND METHODS: Patients with symptomatic coronary artery disease, all on chronic single aspirin treatment were randomized to continue on aspirin or change to clopidogrel. In 219 randomly selected clopidogrel treated patients, platelet reactivity was evaluated by VASP-PRI determination and by use of VerifyNow P2Y12-PRU. The CYP 2C19*2 G/A polymorphism was further determined. RESULTS: The total frequency of clopidogrel resistance was 29.0% by VASP-PRI and 31.6% by VerifyNow-PRU. The number of patients being hetero- and homozygous combined for the CYP 2C19*2 polymorphism (GA/AA) was 64 (29%). Platelet reactivity was significantly higher in patients with the polymorphism compared to wild-type patients (GG). VASP-PRI was 50.9% (SD19) in patients having the polymorphism compared to 38.3% (SD21) in patients with the GG genotype (p = 0.001). Correspondingly, the mean PRU was 165 (SD67) compared to 124 (SD69) (p < 0.001). The frequency of clopidogrel resistance in patients with the polymorphism was 32% compared to 16% in wild-type patients when defined by VASP-PRI (p = 0.006). When defined by PRU (VerifyNow), the corresponding frequencies were 53% and 22% (p < 0.001). CONCLUSIONS: Clopidogrel treated patients with the CYP 2C19*2 polymorphism have significantly increased platelet reactivity compared to patients with the wild-type, evaluated with the VASP determination, and even more pronounced with the VerifyNow P2Y12 method. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00222261.

The influence of tissue factor and tissue factor pathway inhibitor polymorphisms on thrombin generation in stable coronary artery disease.

In patients with stable coronary heart disease (n = 1,001) we investigated the influence of tissue factor (TF) and TF pathway inhibitor (TFPI) polymorphisms on thrombin generation in vivo, measured by prothrombin fragment (F) 1 and 2, and the potential to generate thrombin ex vivo, measured by the calibrated automated thrombogram assay. Additionally, circulating levels of TF and TFPI were correlated to the different parameters of thrombin generation. The TF 5466 and TFPI -399 polymorphisms associated with higher thrombin generation in vivo, the latter also with a prolonged lag time of the thrombin generation ex vivo(p < 0.05 for all).The TF -1812 TT and the TF -603 GG genotypes were associated with lower peak thrombin and a decreased average net rate of thrombin activation during the propagation phases (p ≤ 0.05), and the TFPI -33 TC genotype with prolonged lag time (p < 0.05) and additionally time to peak (p = 0.06). Strong correlations between TFPI levels, prothrombin fragment 1 and 2 as well as calibrated automated thrombogram parameters were observed.