Summary
The vascular subendothelium contains macromolecular structures called microfibrils.
Type VI collagen is one protein found in microfibrils that supports platelet adhesion
and aggregation and we have previously evaluated the roles of platelet receptors and
vWf involved in these processes under physiological shear conditions. Here we investigate
the ability of fibrillin containing elastic microfibrils to support mural thrombus
formation. Our results show that elastic microfibril surfaces support platelet adhesion
under low shear conditions at a level similar to collagen VI tetramers. However, the
degree of aggregation on the elastic microfibril surface is much higher. Both adhesion
and aggregation were shown to be mediated by the GPIIb-IIIa platelet receptor. Elastic
microfibrils do not support the formation of mural thrombi under high shear conditions.
These results suggest roles for both collagen VI and fibrillin containing elastic
microfibrils in modulating the platelet response to blood vessel injury.