High doses of methylene blue/light treatment crosslink the A-alpha-subunit of fibrinogen: influence of this photooxidization on fibrinogen binding to platelets.
Irradiation in the presence of 1 microM methylene blue (MB) inactivates enveloped viruses in human plasma. This method is a useful tool to enhance the safety of human fresh-frozen plasma in blood donor banks. Via a photooxidative mechanism, viral structures as well as plasma proteins, especially fibrinogen, can be damaged. We investigated the effect of MB/light-induced photooxidative modification on the structure of fibrinogen and its function in the interaction with platelets in the concentration range of 150 microM MB. Densitometric scanning of reduced SDS-PAGE showed a decrease in the Aalpha-subunit of fibrinogen as well as an increase in high-molecular-weight (HMW) aggregates with increasing MB concentrations. The HMW aggregates may be due to covalent crosslinking of single Aalpha-subunits via photooxidation induced by MB/light treatment. Fibrinogen treated with high doses of MB (50 microM) showed a weaker binding to the fibrinogen receptor (GP IIb/IIIa) on the platelet surface and a decrease in platelet aggregation after stimulation with ADP and photooxidized fibrinogen. These effects were not detected in fibrinogen isolated from virus-inactivated plasma (1 microM MB). This was in agreement with normal binding of fibrinogen to GP IIb/IIIa on platelets.
Lorenz
M
M
Institute for Transfusion Medicine and Immunohematology, Red Cross Blood Transfusion Service Hessen, Germany.
Müller
M
M
Jablonka
B
B
Vigh
T
T
Kirchmaier
C M
CM
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005340:Fibrinogen / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D008027:Light; D008751:Methylene Blue / Q000032:analysis / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010777:Photochemistry; D010974:Platelet Aggregation / Q000187:drug effects; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D012967:Sodium Dodecyl Sulfate
D007457:Iodine Radioisotopes; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D012967:Sodium Dodecyl Sulfate; D000244:Adenosine Diphosphate; D005340:Fibrinogen; D008751:Methylene Blue