VEGF-A cis-located SNPs on human chromosome 6 associated with VEGF-A plasma levels and survival in a coronary disease cohort

Abstract

Background: Cardiovascular disease (CVD) is the leading cause of death worldwide. Risk stratification of CVD patients may be improved by predictive biomarkers, including genetic markers. Elevated circulating vascular endothelial growth factor A (VEGF-A) levels have been linked to CVD development. We explored whether single nucleotide polymorphisms (SNPs) at the VEGFA locus on human chromosome 6 were associated with VEGF-A levels and clinical outcomes in established CVD. VEGF-A levels were compared between coronary heart disease patients and heart healthy controls.

Methods: Imputed genotypes of 30 SNPs from the VEGFA region for 1935 patients from the Coronary Disease Cohort Study (CDCS) and 1183 individuals from the Canterbury Healthy Volunteers Study (HVOL) were analysed for associations with cardiometabolic parameters. Association with clinical endpoints was assessed using Kaplan-Meier analysis and multivariate regression models. To validate the findings from imputed data, DNA samples of 2027 CDCS patients and 227 HVOL participants were manually genotyped for variants rs6921438 and rs7767396. Baseline plasma VEGF-A assayed by ELISA in 227 HVOL participants was compared with levels in 549 CDCS patients.

Results: Manual genotyping showed rs6921438 AA and rs7767396 GG genotype groups had lower VEGF-A levels at baseline (CDCS: rs6921438 AA (27.7 pg/mL), AG (43.3 pg/mL), GG (63.2 pg/mL), p = 4.49 × 10^{- 22}; rs7767396: GG (27.4 pg/mL), AG (42.8 pg/mL), AA (61.5 pg/mL) p = 3.47 × 10^{- 21}; HVOL rs6921438 AA (12.8 pg/mL), GA (19.9 pg/mL), GG (26.4 pg/mL) p = 0.021; rs7767396 GG (12.6 pg/mL), AG (19.6 pg/mL), AA (25.9 pg/mL) p = 0.029). In the CDCS cohort rs6921438 AA was associated with increased risk of all-cause death (p = 0.03); non ST-elevated myocardial infarction (NSTEMI, p = 0.0003), heart failure (HF, p = 0.035) and major adverse cardiovascular events (p = 0.032); rs7767396 GG was associated with increased NSTEMI (p = 0.001) and HF (p = 0.023) risk; rs6921438 AA (Hazard Ratio (HR) = 6.55 p = 0.017), rs7767396 GG (HR = 0.149, p = 0.017) and VEGF-A (HR = 2.55, p = 0.018) were independent HF admission risk predictors.

Conclusions: Variants rs6921438 and rs7767396 are associated with plasma VEGF-A levels. Both SNPs and VEGF-A may be useful in prognosis for HF after acute coronary events.

Keywords: Outcome; Prognosis; Single nucleotide polymorphism; Vascular endothelial growth factor; rs6921438; rs7767396.

Fig. 1

VEGF-A levels of CDCS and HVOL cohorts for manual genotypes of (A) rs6921438 and (B) rs7767396. Bars represent geometric means with 95% CI error bars. *Indicates genotype groups compared to the reference genotype group (blue bar) of the respective cohort (p < 0.05)

Fig. 2

All-cause death survival plot for CDCS cohort stratified by imputed genotypes of A) rs6921438 and B) rs7767396. Genotypes are colour coded blue for homozygous reference, green for heterozygous and red for homozygous for the minor allele. Patients are risk reported for every 2-year interval

Fig. 3

Survival plots of CDCS rs6921438 manual genotypes for A) all-cause death, B) NSTEMI C) heart failure and D) MACE. Genotypes are colour coded blue for GG, green for GA and red for AA

Fig. 4

Survival plots of CDCS rs7767396 manual genotypes for A) NSTEMI and B) heart failure. Genotypes are colour coded blue for AA, green for AG and red for GG

Fig. 5

Schematic representation of VEGFA region of human chromosome 6 (not to scale). SNPs analysed in the present study are shown in bold. Red boxes indicate lncRNAs. Blue box - coding gene for VEGF-A. Green arrows point to individual SNP locations. Transcription Factor binding sites overlapping analysed SNPs are named