Behavior of protein S during long-term oral anticoagulant therapy.
It has recently been reported that a natural anticoagulant, protein S (PS), is depressed during oral anticoagulation. Since more detailed information is required from the clinical standpoint, we measured plasma levels of PS [both total and free (not complexed) PS antigen], C4b-binding protein (C4bp) and other vitamin K-dependent proteins (factors II, VII, IX, X and protein C) in 60 plasma samples from patients on long-term oral anticoagulant therapy with warfarin. Together with the reduction of other vitamin K-dependent plasma proteins, PS decreased during warfarin treatment, being dependent on the intensity of the therapy. A considerable variation in plasma PS levels was also observed among individuals with a similar intensity of anticoagulation. Plasma concentration of C4bp was closely correlated with total PS level, and free PS/total PS ratio was independent of thrombotest values. These findings indicate that long-term oral anticoagulant therapy results in the suppression of the synthesis of PS, and that its reduction is on the whole balanced with C4bp and vitamin K-dependent coagulation factors. It was suggested that the metabolism of C4bp might be regulated by the plasma PS level, although this hypothesis needs further exploration.
Takahashi
H
H
First Department of Internal Medicine, Niigata University School of Medicine, Japan.
Wada
K
K
Hayashi
S
S
Hanano
M
M
Tatewaki
W
W
Shibata
A
A
D000284:Administration, Oral; D001798:Blood Proteins / Q000032:analysis; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D017293:Protein S; D013997:Time Factors; D014859:Warfarin / Q000008:administration & dosage / Q000494:pharmacology*
D001798:Blood Proteins; D006023:Glycoproteins; D017293:Protein S; D014859:Warfarin