Influence of heparin on the chemotactic activity of human thrombin.

Chemoattractant properties of human thrombin have been studied, by polymorphonuclear leucocyte migration under agarose gel, in the presence of various sulphated macromolecules such as standard heparins, low molecular weight heparins, CY216, K2165, PK10169 and pentosane polysulphate. These compounds did not attract polymorphonuclear leucocytes within the range of concentrations used, whilst thrombin alone is a cytotaxin for these cells. Addition of heparins to thrombin led to an increase in the chemoattractant activity of this enzyme for at least one of the doses studied. Augmentation of the chemoattractant activity of thrombin by heparins was shown at concentrations equivalent to those found in-vivo after administration of therapeutic doses of heparin. Pentosane polysulphate, at the studied concentrations, did not lead to a significant rise in the chemoattractant activity of thrombin.