Effect of dextran on factor VIII (antihemophilic factor) and platelet function

Area of Science:

• Hematology
• Pharmacology
• Coagulation Science

Background:

• Factor VIII (antihemophilic globulin) is crucial for blood coagulation.
• Dextran 70 is a plasma volume expander with potential antithrombotic effects.
• Understanding Dextran's impact on hemostasis is vital for clinical application.

Purpose of the Study:

• To investigate the effects of Dextran 70 infusion on factor VIII properties.
• To analyze changes in factor VIII coagulant activity, factor VIII related antigen, and platelet aggregation.
• To elucidate the mechanism behind Dextran's influence on hemostasis.

Main Methods:

• Healthy volunteers received 500 ml of six percent Dextran 70.
• Factor VIII coagulant activity and factor VIII related antigen levels were measured.
• Ristocetin-induced platelet aggregation was assessed using native and formalin-fixed platelets.
• In vitro experiments were conducted to compare with in vivo effects.

Main Results:

• No significant change in factor VIII coagulant activity was observed.
• A significant, temporary decrease in factor VIII related antigen occurred post-infusion.
• Ristocetin-induced platelet aggregation significantly decreased, peaking a few hours after infusion.
• The observed effects were specific to in vivo Dextran administration.

Conclusions:

• Dextran 70 infusion transiently impairs factor VIII related antigen and platelet function.
• The in vivo effect of Dextran 70 on factor VIII resembles certain variants of von Willebrand's disease.
• These findings suggest a mechanism for Dextran's platelet function-inhibiting and potential antithrombotic properties.