Non-Newtonian behavior of surface layers of human plasma protein systems and a new concept of the initiation of thrombosis

Abstract

Rheogoniometric measurements were made of the viscosity of human plasma and serum systems, and of solutions of fibrinogen and other plasma proteins with and without guard ring in combined Couette and cone and plate geometry at shear rates from 10³ to less than 10⁻¹ sec⁻¹. The exclusion of measurements of surface layers by the use of the guard ring always resulted in Newtonian flow characteristics, while the “overall viscosity”, measured without the guard ring, exhibited non-Newtonian behavior. The addition of 0.4% fibrinogen to 5% plasma or to 0.25% albumin concentration showed a marked increase of overall viscosity, but such addition to 90% plasma or to 5% albumin exhibited no change in non-Newtonian behavior. These and other findings support the introduction of a new concept for the initiation of thrombosis which is based on the formation of polymolecular layers of fibrinogen and other plasma proteins, leading to obstruction of the affected blood vessel and impairment of the circulation. The aggregation of the proteins is considered to occur in two steps, viz. a first adsorption process on the surface of the vessel wall, followed by a growth process in which additional protein molecules adsorb on the first or previously formed adsorption layers.