Placental growth factor


Placental growth factor is a protein that in humans is encoded by the PGF gene.
Placental growth factor is a member of the VEGF sub-family - a key molecule in angiogenesis and vasculogenesis, in particular during embryogenesis. The main source of PGF during pregnancy is the placental trophoblast. PGF is also expressed in many other tissues, including the villous trophoblast.
Placental growth factor is a protein-coding gene and a member of the vascular endothelial growth factor family. PGF is ultimately associated with angiogenesis. Specifically, PGF plays a role in trophoblast growth and differentiation. Trophoblast cells, specifically extravillous trophoblast cells, are responsible for invading maternal arteries. Proper development of blood vessels in the placenta is crucial for proper embryonic development.
Under normal physiologic conditions, PGF is also expressed at a low level in other organs including the heart, lung, thyroid, and skeletal muscle.

Clinical significance

Placental growth factor-expression within human atherosclerotic lesions is associated with plaque inflammation and neovascular growth.
Serum levels of PGF and sFlt-1 are altered in women with preeclampsia. Studies show that in both early and late onset preeclampsia, maternal serum levels of sFlt-1 are higher and PGF lower in women presenting with preeclampsia. In addition, placental sFlt-1 levels were significantly increased and PGF decreased in women with preeclampsia as compared to those with uncomplicated pregnancies. This suggests that placental concentrations of sFlt-1 and PGF mirror the maternal serum changes. This is consistent with the view that the placenta is the main source of sFlt-1 and PGF during pregnancy.1
PGF is a potential biomarker for preeclampsia, a condition in which blood vessels in the placenta are too narrow, resulting in high blood pressure. As mentioned before, extravillous trophoblast cells invade maternal arteries. Improper differentiation may result in hypo-invasion of these arteries and thus failure to widen enough. Studies have found low levels of PGF in women who were diagnosed with preeclampsia later in their pregnancy.