Selective protection of RBCs against photodynamic damage by the band 3 ligand dipyridamole.
BACKGROUND
All studied photosensitizers for virus inactivation impair RBCs. To reduce damage to the RBCs without affecting virucidal activity, selective protection of the RBCs is necessary. The ability of the band 3 ligand, dipyridamole, to react with singlet oxygen and to increase the selectivity of photosterilization was investigated.


METHODS
Solutions of dipyridamole were illuminated in the presence of tetrasulfonated aluminum phthalocyanine (AlPcS(4)) and dimethylmethylene blue (DMMB). Solutions of amino acids, RBCs, and vesicular stomatitis virus (VSV) in RBC suspensions were photodynamically treated in the presence or absence of dipyridamole.


RESULTS
Illumination of a solution of dipyridamole in the presence of AlPcS(4) or DMMB resulted in changes in the optical spectrum of dipyridamole. The photooxidation of dipyridamole was inhibited by azide and augmented by D(2)O, which suggests the involvement of singlet oxygen. Photooxidation of amino acids and photodamage to RBCs was strongly reduced in the presence of dipyridamole. In contrast, photoinactivation of VSV in RBC suspensions was only slightly affected by dipyridamole.


CONCLUSIONS
Dipyridamole can improve the specificity of photodynamic sterilization of RBC concentrates, thereby increasing the practical applicability of this photodecontamination method.
vanSteveninck
J
J
Departments of Molecular Cell Biology and of Immunohematology & Bloodbank, Leiden University Medical Center, The Netherlands.
Trannoy
L L
LL
Besselink
G A
GA
Dubbelman
T M
TM
Brand
A
A
de Korte
D
D
Verhoeven
A J
AJ
Lagerberg
J W
JW
D000998:Antiviral Agents / Q000097:blood* / Q000494:pharmacology; D001790:Blood Physiological Phenomena; D004176:Dipyridamole / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects / Q000528:radiation effects / Q000821:virology*; D006639:Histidine / Q000378:metabolism; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013481:Superoxides / Q000494:pharmacology
D000998:Antiviral Agents; D017319:Photosensitizing Agents; D013481:Superoxides; D006639:Histidine; D004176:Dipyridamole