"In vitro" fibrinolytic activity of a new low molecular weight heparan sulfate.
The fibrinolytic activity, effect on the fibrinolytic activity of plasmin, anticoagulant activity and anti platelet aggregation activity of a low molecular weight heparan sulfate (LMW HS Bal) were investigated "in vitro" on blood plasma obtained from rats and rabbits. LMW HS Bal at concentrations as low as 0.25-2 micrograms/ml prevented thrombin-induced platelet aggregation. At concentrations 25 to 50 times larger it showed no significant anticoagulant activity but a marked fibrinolytic effect. At still larger concentrations LMW HS Bal also potentiated the fibrinolytic activity of plasmin. Conversely, unfractionated heparan sulfate (UHS) at concentrations of 25 to 50 micrograms/ml, only showed anticoagulant activity with no fibrinolytic activity.