Can we extrapolate the outcomes of in vitro studies on murine endothelium to studies of human platelet-endothelium interactions? A technical note

Interactions between vascular endothelium and blood platelets play a crucial role in cardiovascular diseases. Ex vitro models which use endothelial cells and platelets were the essential tools to investigate these interactions and their impact on haemostasis. The impaired interplay between vascular endothelium, blood platelets and leukocytes is believed to contribute to the development of cardiovascular disease. In this study we compared the ability of human (HUVECs) and murine (HECa10) endothelial cells to inhibit human platelet function and reactivity under in vitro conditions. The aliquots of platelet-rich plasma obtained from 20 healthy donors were incubated with murine endothelial cell line HECa10 or human umbilical vein endothelial cells (HUVECs) (10 min, 37°C) prior to agonizing platelets with 5 µM ADP and monitoring platelet reactivity for 10 min using optical aggregation. Significant reduction in ADP-induced platelet aggregation in the presence of endothelial cell cultures remained independent of cell count. HUVECs appeared much more effective in the inhibition of platelet aggregation compared to HECa10 (35.2 ±2.3 AU vs. 43.7 ±2.0 AU, p= 0.025). HECa10 cells have much lower potential to inhibit platelet aggregation than HUVECs. This implies that these two cell lines may not be freely used interchangeably in in vitro experiments. These findings clearly indicate that the outcomes of in vitro studies performed with murine EC lines cannot be unreservedly extrapolated to human platelet-endothelium interactions.