Anticoagulant activity of heparin is not a property of all heparin chains because low molecular weight chains exert their role as inhibitors of factor Xa without anticoagulant activity but with anti-thrombotic effect. This belongs with the peculiar aspect of intravascular metabolism of heparin which entails the clearance of circulating heparin by endothelial cells. These latter release heparin metabolites with potential antithrombotic role (GAGs). We studied 6 healthy subjects (3F 3M aged 28-33 y) who underwent aerosol administration of an initial dose of 4.500 UI/Kg unfractionated heparin followed by a second administration of the same dose after 7 days. We measured aPTT, PT, anti Xa plasma activity, ATIII, Heptest, heparin-like compounds and GAGs. The measure-ments were carried out each day for 14 days. The intrapulmonary administration of heparin was safe and none of the subjects suffered from any side effect. We found that the treatment did not cause any significant anticoagulant activity as demonstrated by the normal values of aPTT, PT and ATTII. On the other hand, we found that anti Xa plasma activity was increased immediately after the aerosol with a slow decrease along the 7 days after. Beside this finding we demonstrated the presence in plasma of GAGs and heparinlike substances which support the hypothesis of intracellular metabolism of heparin. All these substances may exert a long-lasting antithrombotic effect which can be of great interest in clinical practice.
|Number of pages||1|
|Issue number||SUPPL. 1|
|Publication status||Published - 1996|
ASJC Scopus subject areas