DIFFERENTIAL LECTIN-BINDING TO MICROVASCULAR ENDOTHELIAL GLYCOCONJUGATES DURING NORMAL ANGIOGENESIS IN THE CHICK CHORIOALLANTOIC MEMBRANE

The ontogenesis of endothelial glycoconjugate expression during normal angiogenesis and microvascular development remains unknown. Using int ravital fluorescent microscopy, we studied temporal and spatial lectin binding to carbohydrate moieties of luminal microvascular endothelia of the chick embryo chorioallantoic membrane (CAM) during Days 4.5 to 6.0 of the 21-day incubation. We used a battery of eight FITC-lectins (100-200 mu g/ml). Fluorescent images from precapillary, capillary, an d postcapillary segments of the lectin-perfused microvascular units we re analyzed by image analysis software to quantitate differences in le ctin binding. Results served to indicate a significant decrease in lec tin binding to terminal N-acetyl glucosamine, N-acetyl galactosamine, and the N-acetyl galactosamine disaccharide in the glycocalyx of pre- and postcapillary vessels from Day 4.5 to Day 5.0. Lectin binding to N -acetyl glucosamine and N-acetyl galactosamine subsequently increased at Days 5.0 and 6.0. In the capillaries, lectin binding to endothelial galactose, fucose, and sialic acid increased significantly from Day 5 .5 to Day 6.0. That these temporal changes in Lectin binding to endoth elial luminal glycoconjugates coincide with concomitant changes in CAM microvascular permeability (Rizzo er al., in press) serves to suggest a possible association between expression of endothelial glycoconjuga tes and the ontogeny of microvascular permselectivity during normal an giogenesis. (C) 1995 Academic Press, Inc.