Balance of antiangiogenic and angiogenic factors in the context of the etiology of preeclampsia.

The "two-stage disorder" theory that is assumed for the etiology of preeclampsia hypothesizes that antiangiogenic and angiogenic factors and/or placental debris play an important role in this disorder. The physiological actions of placental debris occur via the balance between antiangiogenic and angiogenic factors. Accordingly, this balance between antiangiogenic and angiogenic factors should be investigated to elucidate the various pathological features of preeclampsia. Their accurate evaluation is needed to investigate not only antiangiogenic factors (such as sFlt-1 and sEng) and angiogenic factors (such as vascular endothelial growth factor, placental growth factor and transforming growth factor-β) but also the expression level of their receptors such as Flt-1 and Eng. However, it is ethically and technically difficult to investigate the above-mentioned factors at antepartum in human patients. The examination of the ratios of sFlt-1/vascular endothelial growth factor receptor ligands and sEng/transforming vascular endothelial growth factor-β and the use of experimental animal models may help in elucidating various unresolved issues in preeclampsia.