LOCALIZATION OF VASCULAR ENDOTHELIAL GROWTH-FACTOR AND ITS RECEPTOR, FIT, IN HUMAN PLACENTA AND DECIDUA BY IMMUNOHISTOCHEMISTRY

Vascular endothelial growth factor is a secreted angiogenic growth fac tor the mRNA of which is present in the placenta. The mRNA encoding th e vascular endothelial growth factor receptor, fit, has also been demo nstrated in placenta, with trophoblast appearing to be a novel site of fit expression. We investigated the expression of both vascular endot helial growth factor and fit-like immunoreactivity in first trimester and term placentae. In the first trimester, vascular endothelial growt h factor immunoreactivity was localized to placental macrophages (Hofb auer cells), and in decidua, to glandular epithelium and maternal macr ophages. In the term placenta, vascular endothelial growth factor immu noreactivity was present in extravillous trophoblast and in extracellu lar material. Fit immunoreactivity was demonstrated on extravillous tr ophoblast in first trimester and term, and on Hofbauer cells within pl acental villi. This complex pattern of both vascular endothelial growt h factor and fit-like immunoreactivity suggests that vascular endothel ial growth factor may be involved not only in the regulation of placen tal angiogenesis, but also in trophoblast invasion.