Effects of unfractionated and fractionated heparin on platelet function.
Heparin-induced alterations of platelet function have repeatedly been reported over the last 30 years. The development of low-molecular-weight (LMW) heparin fractions prompted us to compare the effect of unfractionated (UF) heparin and LMW heparin on platelet function. Heparin was applied intravenously to healthy volunteers in a dose of 100 U (antifactor Xa)/kg body weight. Sequential evaluation of platelet function ex vivo confirmed that UF heparin may activate platelets in vivo. Studying the ADP-induced fibrinogen binding to platelets in vivo, we were able to show that the effect of heparin on platelets is antibody- and antithrombin-III-independent. LMW heparin fractions in general exhibit a reduced platelet activating activity although there are differences between the LMW heparin fractions available. The stimulating effect of LMW heparin on platelets disappears below a mean molecular weight of 3,000 daltons.
Heinrich
D
D
Department of Internal Medicine, University Hospital, Justus Liebig University, Giessen, FRG.
Görg
T
T
Schulz
M
M
D001792:Blood Platelets / Q000187:drug effects*; D005591:Chemical Fractionation; D015951:Factor Xa; D006493:Heparin / Q000494:pharmacology*; D006495:Heparin, Low-Molecular-Weight / Q000494:pharmacology*; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count / Q000187:drug effects; D015842:Serine Proteinase Inhibitors
D006495:Heparin, Low-Molecular-Weight; D015842:Serine Proteinase Inhibitors; D006493:Heparin; D015951:Factor Xa