The distribution of fibronectin in the placental bed in normotensive and hypertensive human pregnancies

Summary Endovascular trophoblast invasion into the spiral arteries of the placental bed is restricted to the decidual segments in pregnancy-associated hypertension (pre-eclampsia). Little is known about mechanisms that control trophoblast invasion. Extracellular matrix proteins such as fibronectin could be involved, as they are in other invasive processes. The observation of increased plasma fibronectin levels in patients that will develop pre-eclampsia (Ballegeer et al., 1989) prompted us to study the distribution of this glycoprotein in the placental bed of normotensive and hypertensive pregnant patients. Paraffin embedded sections were stained for fibronectin using the indirect peroxidase labeled antibody technique. Spiral arteries undergoing physiological changes stained virtually negative. In vessels with subintimal thickening an occasional fibronectin positive lining of endothelium and positive areas in the fibrous subintimal cushions could be found. The most intensive staining for fibronectin however was found in the arteries with acute atherosis, i.e., the vascular lesion that is thought to be associated with pre-eclampsia.