BACKGROUND: Adherence of platelets to endothelial cells may be a significant event in the development of vascular thrombosis. Existing models, which examine platelet-endothelial cell interactions, compromise endothelial cell integrity or use radioactivity to identify platelets that adhere to endothelial cells. We report a novel method for in vitro detection of platelet-endothelial cell adhesion that allows endothelial cells to remain as an intact monolayer and for visualization of individual platelets.

METHODS: Fluorescently labeled platelets were incubated with a confluent monolayer of endothelial cells. Laser scanning cytometry (LSC) identified platelets bound to endothelial cells based on their fluorescent signals.

RESULTS: LSC detection of platelets reliably reproduced well-described findings of thrombin-induced platelet-endothelial cell adhesion. Results demonstrating reduced adhesion with a glycoprotein IIb-IIIa-specific blocking monoclonal antibody confirmed the specificity of the LSC detection of platelet-endothelial cell adhesion.

CONCLUSIONS: LSC is a novel method for detecting platelet--endothelial cell adhesion. Its advantages over other methods are: (a) endothelial cells remain undisturbed and adherent throughout; (b) the ability to detect individual bound platelets and subpopulations; (c) the ability to store images and slides and then relocate, revisualize, and reanalyze individual cells or cell populations of interest; and (d) no radioactivity.