Gene expression patterns of vascular endothelial growth factor (VEGF-A) in human placenta from pregnancies with intrauterine growth restriction

Objective: In this study, we describe changes in gene expression pattern of vascular endothelial growth factor (VEGF)-A in human placenta obtained from pregnancies with intrauterine growth restriction using placenta from normal pregnancies as control. Methods: We compared gene expression of VEGF-A in placental samples from Intrauterine growth restriction (IUGR) pregnancies versus placenta obtained from normal pregnancies. Among potential confounders, important clinical informations were also analyzed. Results: In the IUGR group, the VEGF-A gene was overexpressed compared to the normal pregnancy group (Ln 2(beta-actin)(alpha): 1.32; Ln 2(GADPH)(alpha): 1.56). There was no correlation between the degree of growth restriction and VEGF-A gene expression (Ln 2(0-5 percentile)(alpha): 0.58; Ln 2(5-10 percentile)(alpha): 0.64). Within the IUGR group, there was a trend toward a positive correlation between placental VEGF-A gene activity and gestational age at delivery (Ln 2(< 33 weeks)(alpha): 1.09; Ln 2(33-37 weeks)(alpha): 1.27; Ln 2(> 37 weeks)(alpha): 1.35). Conclusions: Our findings suggest that the increase in placental expression of the VEGF-A gene and the resultant stimulation of angiogenesis are a response to hypoxic environment developing in the placental tissue in IUGR. Thus, it appears to be a secondary event rather than a primary factor in the development of IUGR There is a trend toward a positive correlation between gestational age and placental VEGF-A gene activity.