Fig. 2.

Increase in extracellular adenosine has differential effects on VEGF and sFlt-1. Placental explants were cultured in 6% or 1% oxygen in the presence or absence of Ado (20 μM). Exogenous Ado had no effect on VEGF secretion under either oxygen tension (A) but significantly increased sFlt-1 release in 6% oxygen (B). Placental explants were cultured under normoxic (6% oxygen) or hypoxic (1% oxygen) conditions in the presence or absence of dipyridamole (DP). C and D: under hypoxic conditions, there was no statistically significant effect of DP on either sFlt-1 or VEGF, indicating the possibility that adenosine signaling pathways are already saturated under these conditions. Under normoxic conditions, however, there were differential effects, as sFlt-1 secretion was increased significantly, while VEGF secretion was unaffected. Error bars represent means ± SD, and relevant P values are displayed.