Summary
It has been suggested that proteins, unlike lipids, are not protected against oxidative
damage by antioxidants in plasma. We have studied the effect of photodynamic virus
inactivation treatment of fresh human plasma on coagulation factor activities. Photodynamic
treatment generates singlet oxygen which causes inactivation of fibrinogen and factor
VIII. Other coagulation factors or anticoagulant proteins are clearly less affected.
We found that there is an inverse correlation between the extent of coagulation factor
inactivation during the treatment and the plasma ascorbate concentration. The inactivation
of coagulation factors was prevented in a dose-dependent manner by adding ascorbate
to the plasma before the treatment. Ascorbate was consumed during the treatment at
an apparently linear rate. Oxidation of urate and coagulation factors was enhanced
when ascorbate had disappeared from plasma. These results indicate that ascorbate
is a primary antioxidant against photooxidation in plasma and that it effectively
prevents oxidative damage to coagulation factors and other proteins.
