Glycoprotein Ia C807T gene polymorphism and increased risk of recurrent acute coronary syndromes: a five year follow up

Common Variant in Glycoprotein Ia Increases Long-Term Adverse Events Risk After Coronary Artery Bypass Graft Surgery

BACKGROUND

This study was aimed to investigate the clinical relevance between glycoprotein Ia (GPIA) rs1126643C/T polymorphism and the outcome of coronary artery disease after coronary artery bypass graft (CABG) surgery and explore the involved potential mechanisms.

METHODS AND RESULTS

We genotyped GPIA rs1126643 polymorphism of 1592 patients who underwent CABG and followed up for a median period of 72.8 months. Patients who are GPIA rs1126643 T-allele carriers have a higher major adverse cardiac or cerebrovascular events risk post-CABG than those who are CC homozygotes (hazard ratio [HR]=1.29; P=0.022). The clinical association between the risk allele (T) carriage and major adverse cardiac or cerebrovascular events was confirmed in another cohort study, which included 646 CABG patients from various health centers across China. Meanwhile, rs1126643 T allele was also linked with increased risk of major adverse cardiac or cerebrovascular events (HR=1.73; P=0.019). To explore the underlying mechanisms, we prospectively recruited 131 coronary artery disease patients, assessed their platelet aggregation function, and focused on detecting their GPIA mRNA level and protein expression. Results showed that patients with rs1126643 T allele have elevated platelet aggregation activity (P=0.029) when protein expression is increased (P<0.001) and not affected by glycoprotein Ia mRNA level.

CONCLUSIONS

The synonymous common variant, GPIA rs1126643, increases the long-term adverse events risk of CABG by augmenting GPIa protein expression and enhancing platelet aggregation function. This finding can serve as the implication of improving secondary prevention of CABG patients.

Functional Effect of Platelet Membrane Glycoprotein Ia Gene Polymorphism in the Pathogenesis of Unstable Angina Pectoris

The functional effect of platelet membrane glycoprotein Ia ( GPIa) gene 807C/T polymorphism in unstable angina pectoris (UAP) pathogenesis was investigated in Chinese Han individuals. Collagen type I-induced platelet aggregation was measured in 33 healthy subjects. Plasma levels of α-granule membrane protein (GMP-140) were measured in 33 healthy subjects and in 35 patients with recentonset angina at rest within 24 h of hospitalization. Platelet membrane GPIa gene 807C/T polymorphism was determined in all subjects. Lag-time before 30% platelet aggregation was significantly longer in CC genotype than in TC genotype healthy subjects, although there was no significant difference in maximal platelet aggregation between healthy subjects with either genotype. Plasma GMP-140 levels were significantly higher in TC genotype patients compared with CC genotype patients or healthy subjects; a significant difference was also observed between the latter two groups. It was concluded that rapid initiation of collagen-induced platelet aggregation may be associated with the platelet membrane GPIa T807 allele, which may be important in UAP pathogenesis.

Angiotensin-converting enzyme 2 A1075G polymorphism is associated with survival in an acute coronary syndromes cohort

BACKGROUND

Polymorphisms of the angiotensin-converting enzyme 2 (ACE2) gene, which is located on the X chromosome, have been associated with hypertension and left ventricular hypertrophy in previous studies. We tested the hypothesis that the rare allele of an ACE2 gene polymorphism was associated with risk factors for and adverse outcome after acute coronary syndrome (ACS) events.

METHODS

Patients (n = 1,042) were recruited after admission for an ACS event and were genotyped for the A1075G polymorphism of the angiotensin-converting enzyme 2 gene. This genetic marker was tested for association with baseline measurements, echocardiographic measurements, and clinical outcome, over a median 2.19 years follow-up. As the ACE2 gene is X-linked, analyses were performed separately for males and females. Patients were predominantly of European ethnicity (90.1%).

RESULTS

The A1075 allele was significantly associated with covariate-adjusted mortality in male patients (hazard ratio 1.95, 95% CI 1.10-3.46, P = .047) but not unadjusted (hazard ratio 1.14, 95% CI 0.736-1.76, P = .56). The G1075 (P < .035) allele was more frequent in patients of Maori compared to European ancestry. E/E', an echocardiographic index of left ventricular diastolic function and filling pressure, was higher in males in the A1075 group (G allele group 10.5 [95% CI 10.0-11.0], A allele group 11.4 [95% CI 10.8-12.1], P = .024). A1075 genotype was significantly associated with male survival in the absence of (mortality: A 12.8%, n = 39; G 29.2%, n = 48; P = .037) but not in the presence of beta-blocker treatment (mortality: A 13.5% n = 273; G 8.2% n = 304, P = nonsignificant).

CONCLUSIONS

The A1075 allele was associated with covariate-adjusted mortality in male patients.

Association of polymorphisms in platelet and hemostasis system genes with acute myocardial infarction

BACKGROUND

Genetic polymorphisms may affect the balance between coagulation and fibrinolysis and thereby affect individual vulnerability to acute myocardial infarction (MI) among patients with underlying coronary atherosclerosis.

METHODS

We enrolled 1375 patients with an initial clinical presentation of coronary disease. We genotyped 49 single nucleotide polymorphisms (SNPs) in 9 coagulation system genes and compared patients who had an initial acute MI with patients who presented with stable exertional angina.

RESULTS

An SNP in CD36 (rs3211956) was significantly (P = .04) more common among patients who presented with acute MI (minor allele frequency 10.5%) than patients with stable exertional angina (minor allele frequency 8.0%). This association became marginally significant, however, after adjustment for conventional cardiac risk factors in an additive genetic model (odds ratio 1.34, CI 1.00-1.88, P = .053). An SNP in ITGB3 (Leu59Pro, rs5918) was slightly, but not significantly (P = .083), more common among patients with acute MI (minor allele frequency 14.5%) than among patients with stable exertional angina (minor allele frequency 12.0%). Two linked SNPs in THBD (Ala473Val, rs1042579; and rs3176123) were slightly, but not significantly (P = .079 and 0.052, respectively), less common among patients with acute MI (minor allele frequency 16.1%) than among patients with stable exertional angina (18.7% and 19.0%, respectively).

CONCLUSIONS

Four SNPs in platelet glycoprotein and hemostatic genes were nominally associated with acute MI rather than stable exertional angina as the initial clinical presentation of coronary artery disease. These findings are suggestive but require independent confirmation in larger studies.

Genetic Polymorphisms of Platelet Glycoprotein Ia and the Risk for Premature Myocardial Infarction

OBJECTIVES

The aim of this research was to evaluate the effect of genetic polymorphisms C807T and G1648A of platelet glycoprotein Ia (GPIa), on the risk for myocardial infarction (MI) and on the release of soluble CD40 ligand (sCD40L) during the acute phase of MI and one year after the event.

BACKGROUND

C807T and G1648A polymorphisms affect the density of GPIa on platelet surface, but their effect on the risk for MI and the release of sCD40L is unknown.

METHODS

The study population consisted of 219 patients with premature MI and 389 controls. One year after the event, 67 patients and 232 controls were recalled for the follow-up study.

RESULTS

The risk for MI in 807TT was 2.296 (95% confidence interval [CI]: 1.187 to 4.440) p < 0.05 versus CC + CT, 2.269 (95% CI: 1.085 to 4.745) p < 0.05 versus CC, and 2.135 (95% CI: 1.080 to 4.219) p < 0.05 versus CT. During the acute phase of MI, sCD40L was higher in 807CT + TT compared with 807CC (p < 0.01), an effect persisting after one year (p < 0.01). The carriage of 807T allele was an independent predictor for sCD40L during the acute phase of MI (beta = 9.442 [standard error (SE): 2.526], p = 0.001) and in the same patients one year later (beta = 8.282 [SE: 2.044], p = 0.001). In healthy individuals, 807T allele was associated with higher sCD40L levels compared with 807CC (p < 0.05), only among those with von Willebrand factor greater than or equal to median.

CONCLUSIONS

Genetic polymorphism C807T increases the risk for premature MI. 807T allele is an independent predictor for sCD40L levels during the acute phase of premature MI as well as one year after the event, while it is associated with elevated sCD40L levels in healthy subjects, only in the presence of high von Willebrand levels.