Altered villus vessel fibronectin in preeclampsia.

Fibronectin is a high molecular-weight glycoprotein found in most tissues and body fluids. Maternal plasma fibronectin levels have been shown to be elevated in preeclampsia, but little is known about placental fibronectin in preeclampsia. Fibronectin tissue distribution in placental villi was "blindly" graded by two examiners using placentas from eight nonpreeclamptic and six preeclamptic pregnancies. Selected frozen sections of normal-appearing areas from each placenta were incubated with rabbit antihuman fibronectin antiserum and then stained with fluorescein isothiocyanate-conjugated goat antirabbit immunoglobulin G and examined by fluorescent microscopy. We found less intensity of fetal vessel fibronectin staining in villi from placentas from preeclamptic pregnancies than in those of normal pregnancies (p less than 0.02, Mann-Whitney U test). It is unclear why fetal villous vessels in preeclampsia have decreased tissue fibronectin, but this may reflect an additional vascular abnormality associated with the preeclampsia syndrome.