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Plasma PIVKA proteins in rabbits given warfarin
A Zivelin1, L V Rao, S I Rapaport
1Department of Medicine, University of California, San Diego, USA.
Thrombosis Research
|June 1, 1996
Summary
Warfarin treatment in rabbits revealed partially carboxylated vitamin K dependent coagulation factors (PIVKA) for factors VII, IX, and X. Notably, factor IX showed a significant antigen excess, indicating impaired carboxylation.
Area of Science:
- Biochemistry
- Hematology
- Pharmacology
Background:
- Vitamin K is essential for the proper function of specific blood coagulation factors.
- Warfarin is an anticoagulant that inhibits vitamin K metabolism.
- Partially carboxylated forms of vitamin K dependent coagulation factors (PIVKA) can indicate impaired vitamin K activity.
Purpose of the Study:
- To investigate the presence and characteristics of PIVKA in rabbits treated with warfarin.
- To quantify PIVKA for specific vitamin K dependent coagulation factors.
Main Methods:
- Rabbits were treated with warfarin.
- Plasma levels of coagulation factors were measured using specific assays.
- Antigen levels were compared to functional activity to detect PIVKA.
- Barium citrate adsorption was used to assess factor IX properties.
Main Results:
- Prothrombin (factor II) PIVKA was absent, confirming previous findings.
- PIVKA for factors VII, IX, and X were detected in warfarin-treated rabbits.
- A significant excess of factor IX antigen over its activity was observed.
- A substantial portion of factor IX antigen remained after barium citrate adsorption.
Conclusions:
- Warfarin treatment in rabbits leads to the accumulation of PIVKA for factors VII, IX, and X.
- Factor IX appears particularly susceptible to impaired carboxylation under warfarin therapy.
- These findings highlight the differential impact of warfarin on vitamin K dependent coagulation factors.