ERYTHROCYTE AGGREGATION AND ERYTHROCYTE DEFORMABILITY MODIFY THE PERMEABILITY OF ERYTHROCYTE ENRICHED FIBRIN NETWORK

Intravascular thrombus formed under low shear conditions consists of r ed cells enmeshed within a fibrin network. Since red cells reduce the permeability of fibrin network by surface drag and by volume occupancy the significance of red cell aggregability and deformability in netwo rk permeability needs examination. In this study networks were develop ed by the addition of thrombin to washed red cells suspended in platel et free plasma. The effects of the polymers polyvinylpyrrolidone (PVP) and poloxamer 188 on network permeability were compared to gauge the influence of red cell aggregation. Both polymers increase network perm eability by an action on fibrin polymerisation but PVP alone enhances red cell aggregation. PVP was found to increase network permeability s ignificantly both by increasing the permeability of the fibrin compone nt of the network and by increasing red cell aggregation and thus redu cing red cell surface drag. In separate experiments red cells were pre -treated with heat, glutaraldehyde, or diamide to reduce cell deformab ility. Decreased cell deformability caused significant reductions in n etwork permeability. This was ascribed to the reduced aggregability of hardened red cells. Red cell aggregation during coagulation enhances molecular transport through modifying the network. This may have impli cations for the penetration of fibrinolytic agents.