Vascular endothelial growth factor and placental growth factor release in cultured trophoblast cells under different oxygen tensions

The oxygen status of the placenta during pregnancy is unclear although it has been hypothesised that in pre-eclampsia large regions of the placenta are hypoxic. Circulating levels of vascular endothelial growth factor (VEGF) are increased in women with pre-eclampsia, while circulating placental growth factor (PIGF) levels are decreased. We hypothesise that secreted levels of VEGF are increased in cultures of trophoblast cells under lowered oxygen conditions while secreted levels of PIGF are alternatively regulated. Primary isolates of first trimester and term cytotrophoblasts cells were cultured in 20 and 5% oxygen for 24 h. There was a significant increase in the levels of VEGF secreted from first trimester and term cytotrophoblast cells cultured under lowered oxygen conditions compared to the controls while there was a significant decrease in the secreted levels of PIGF in the same cell populations (as measured by ELISA). In first trimester and term trophoblast cells the presence of VEGF (121, 165 and 189) and PIGF (132 and 152) mRNA were demonstrated in both groups by reverse transcription-polymerase chain reaction (RT-PCR). These altered levels of secreted VEGF and PIGF may be released as compensatory molecules in the pathogenesis of diseases such as pre-eclampsia and intrauterine growth restriction.