SDF1 gene variation is associated with circulating SDF1alpha level and endothelial progenitor cell number: the Bruneck Study

Abstract

Background: Stromal cell-derived factor-1 (SDF1) and its receptor CXC chemokine receptor 4 (CXCR4) play a critical role in progenitor cell homing, mobilization and differentiation. It would be interesting to assess the predictive value of SDF-1alpha level for EPC number, and to ascertain whether there is a relationship between SDF1 gene variation, plasma SDF-1alpha level, and the number and function of circulating EPCs. We also tested whether EPC number and function was related to CXCR4 gene variation.

Methodology and principal findings: We genotyped a cohort of individuals who participated in the Bruneck Study for single nucleotide polymorphisms (SNPs) in the SDF1 and CXCR4 genes, and measured blood SDF1alpha level as well as EPC number and function. SDF1alpha levels were correlated with age, gender, alcohol consumption, circulating reticulocyte numbers, and concentrations of matrix metalloproteinase-9, C-reactive protein, cystatin C, fibrinogen and homocytein. In blood samples taken in 2005, EPC number was inversely associated with SDF1alpha level (p<0.001). EPC number in 2005 was also inversely associated with SDF1alpha level in 2000 (p = 0.009), suggesting a predictive value of plasma SDF1alpha level for EPC number. There was an association between the SDF1 gene rs2297630 SNP A/A genotype, increased SDF1alpha level (p = 0.002) and lower EPC number (p = 0.006).

Conclusions: Our data indicate that a SDF1 gene variation (rs2297630) has an influence on SDF1alpha level and circulating EPC number, and that plasma SDF1alpha level is a predictor of EPC number.

Figure 1

Panel A shows near normal distribution of SDF1α in the Bruncek study population. Panel B displays the association between SDF-1α measured in 2000 and in 2005 and age (r = 0.270, p<0.001). Panel C illustrates the correlation between SDF1α levels and EPC number in 2005. The regression line demonstrates clearly that SDF1α levels are inverse association with EPC number. Panel D illustrates the association between EPC numbers in 2005 and SDF1α level in 2000 (tertile groups). SDF-1 tertile groups are defined as follows: T1<2409, T2 2409–2753 and T3>2753. The box plots indicating EPC number median and IQRs. Notably, EPC numbers are significant associated inversely with SDF-1α levels, especially much low EPC number were likely observed in the top tertile group of SDF-1 levels.

Figure 2. Associations of the SDF1 rs2297630 SNP (2000) with EPC number (median and IQR, A) and blood SDF1α level (arithmetic means and SD, B) assessed in the 2005 evaluation of the Bruneck Study.