Rationale VEGF impacts angiogenesis, atherosclerosis and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings. Objective Our aim was to identify genetic variants associated with circulating VEGF levels using an unbiased genome-wide approach and explore their functional significance with gene expression and pathway analysis. Methods and results We undertook a genome-wide association study (GWAS) of serum VEGF levels in 3,527 participants of the Framingham Heart Study (FHS), with pre-planned replication in 1,727 participants from two independent samples, the STANISLAS Family Study (SFS) and the Prospective Investigation of the Vasculature in Uppsala Seniors study (PIVUS). One hundred and forty SNPs reached genome-wide significance (p<5×10−8). We found evidence of replication for the most significant associations in both replication datasets. In a conditional GWAS 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, p=6.11×10−506 and p=1.47×10−12), rs6993770 (8q23.1, p=2.50×10−16) and rs10738760 (9p24.2, p=1.96×10−34). A genetic score including these four SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the GWAS were significantly associated with VEGF mRNA levels in PBMCs. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR). Conclusions Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.

Background-Neuregulin-1 (NRG-1) is a paracrine factor released by microvascular endothelial cells that has cardioprotective effects in animal models of heart failure. However, circulating NRG-1 has not been studied in human heart disease. We used a novel immunoassay to test whether circulating NRG-1␤ is associated with disease severity and clinical outcomes in chronic heart failure. Methods and Results-Serum NRG-1␤ was quantified in 899 outpatients in the Penn Heart Failure Study, a referral cohort representing a broad spectrum of systolic heart failure. Circulating NRG-1␤ was significantly elevated in patients with worse disease severity (median, 6.2 ng/mL for New York Heart Association class IV versus 4.4 ng/mL for class I; Pϭ0.002). In adjusted models, NRG-1␤ was independently associated with an increased risk of death or cardiac transplantation over a median follow-up of 2.4 years (adjusted hazard ratio, 1.58; 95% confidence interval, 1.04 to 2.39; Pϭ0.03 comparing fourth versus first NRG-1␤ quartile). Associations with outcome differed by heart failure cause and symptom severity, with the strongest associations observed in patients with ischemic cardiomyopathy (interaction Pϭ0.008) and New York Heart Association class III/IV symptoms (interaction Pϭ0.01). These findings were all independent of brain natriuretic peptide, and assessment of NRG-1␤ and brain natriuretic peptide jointly provided better risk stratification than each biomarker individually in patients with ischemic or New York Heart Association class III/IV heart failure. Conclusions-Circulating NRG-1␤ is independently associated with heart failure severity and risk of death or cardiac transplantation. These findings support a role for NRG-1/ErbB signaling in human heart failure and identify serum NRG-1␤ as a novel biomarker that may have clinical applications. (Circulation. 2009;120:310-317.)