| Although endothelium lines blood vessels throughout the circulation, it exhibits highly specialized functions in different vascular sites. Developmental studies indicate that the lung's macro- and microvasculature arises from distinct embryological origins. These findings suggest that endothelial cell phenotypes may be partly established through a genetic pre-program. We sought to identify a means to discriminate between these cell types that would allow for their selective isolation. Screening for reactivity with nine different lectins revealed that Glycine max and Griffonia simplicifolia lectins preferentially bind microvascular endothelia (RPMVEC) whereas Helix pomatia lectin preferentially binds macrovascular endothelia (RPAEC). This unique lectin-binding pattern provided a mechanism by which cells could be isolated, and is retained even when the two cell types are co-cultured. Previous studies revealed that RPMVECs proliferate faster than RPAECs. Microarray analysis confirmed that RPMVECs have more VEGF than RPAECs, however, when VEGF was withdrawn, growth was similarly inhibited in RPAECs and RPMVECs. |
