The potency of heparin-like activity of glycosaminoglycans released by human endothelial cells in culture.

Glycosaminoglycans isolated from culture medium conditioned by human endothelial cells showed heparin-like anti-thrombin III cofactor activity measured by Xa inhibition. Their activity was relatively weak, 0.1% of the potency of heparin, but was approximately 5-fold more potent than that of glycosaminoglycans derived from vascular smooth muscle cells.