Modulation of Endothelium by Heparin and Related Polyelectrolytes

Abstract

The vascular endothelium is an important me diator of the hemostatic balance. In addition to shielding subendothelial tissue factor from flowing blood, endothe lial cells produce a number of substances which favor an antithrombotic state including TFPI and tPA. The ability of polyelectrolytes such as heparin and defibrotide to modulate endothelial function is examined using animal models and human studies. Like heparin, defibrotide is observed to increase plasma TFPI antigen levels. Addi tionally, defibrotide administration is observed to in crease plasma tPa antigen levels and to decrease PAI, TF and endothelin levels. Modulation of endothelial function by defibrotide may account for its beneficial effect in PAOD.