Use of a flexible thiopyrylium photosensitizer and competitive inhibitor for pathogen reduction of viruses and bacteria with retention of red cell storage properties.
BACKGROUND
Progress in developing photochemical methods for pathogen reduction of red blood cells (RBCs) has been hampered by hemolysis. A flexible, nucleic acid-intercalating thiopyrylium (TP) dye that is only photochemically active in the bound state and a competitive inhibitor of RBC membrane binding, dipyridamole (DP), was used to reduce photoinduced hemolysis stemming from free- and membrane-bound dye.


METHODS
Oxygenated leukodepleted 20% hct RBC suspensions were deliberately inoculated with virus or bacteria, incubated with 200 micromol per L DP and less than or equal to 100 micromol per L TP, illuminated with 1.1 J/cm(2) of red light, and titered. RBC suspensions containing 200 micromol per L DP and 160 micromol per L TP were identically phototreated, concentrated to 45% hct, and assayed for RBC storage properties.


RESULTS
In RBC suspensions containing DP, TP photoinactivated vesicular stomatitis virus, pseudorabies virus, duck hepatitis B virus, bovine virus diarrhea virus, extracellular human immunodeficiency virus (HIV) to the limit of detection and 6.2 log intracellular HIV. More than 5 log inactivation of 6 bacterial species was demonstrated. DP prevented approximately 30% of TP binding to RBCs. Phototreated RBCs that were subsequently stored for 42 days exhibited acceptable levels of hemolysis, morphology scores, extracellular pH, ATP, glucose utilization rates, and lactate production. Treated samples exhibited substantially increased potassium efflux compared to controls.


CONCLUSIONS
Use of TP photosensitizer and DP enables significant levels of pathogen reduction while retaining most, but not all RBC properties during 42 day storage.
Wagner
Stephen J
SJ
American Red Cross Biomedical Services, Holland Laboratory, Blood and Cell Therapy Development, Rockville, Maryland, USA. wagners@usa.redcross.org
Skripchenko
Andrey
A
Cincotta
Louis
L
Thompson-Montgomery
Dedeene
D
Awatefe
Helen
H
D000814:Aniline Compounds; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001424:Bacterial Infections / Q000517:prevention & control*; D001793:Blood Preservation / Q000379:methods*; D004910:Erythrocyte Membrane / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects* / Q000382:microbiology / Q000821:virology; D006461:Hemolysis; D006801:Humans; D017319:Photosensitizing Agents; D011714:Pyrans; D014777:Virus Diseases / Q000517:prevention & control*; D014780:Viruses / Q000187:drug effects / Q000254:growth & development
D000814:Aniline Compounds; D017319:Photosensitizing Agents; D011714:Pyrans; C084408:2-methyl-4,6-bis(N,N-dimethylaminophenyl)pyrylium