Ultraviolet C light pathogen inactivation treatment of platelet concentrates preserves integrin activation but affects thrombus formation kinetics on collagen in vitro.
BACKGROUND
Ultraviolet (UV) light illumination in the presence of exogenously added photosensitizers has been used to inactivate pathogens in platelet (PLT) concentrates for some time. The THERAFLEX UV-C system, however, illuminates PLT concentrates with UV-C light without additional photoactive compounds. In this study residual PLT function is measured in a comprehensive paired analysis of UV-C-treated, gamma-irradiated, and untreated control PLT concentrates.


METHODS
A pool-and-split design was used with buffy coat-derived PLT concentrates in 65% SSP+ additive solution. Thrombus formation kinetics in microfluidic flow chambers onto immobilized collagen was investigated with real-time video microscopy. PLT aggregation, membrane markers, and cellular metabolism were determined concurrently.


RESULTS
Compared to gamma-treated and untreated controls, UV-C treatment significantly affected thrombus formation rates on Days 5 and 7, not Day 2. PLT degranulation (P-selectin) and PLT apoptosis (annexin V binding) was slightly but significantly increased from Day 2 on. UV-C treatment moreover induced integrin αIIb β3 conformational changes reminiscent of activation. However, subsequent integrin activation by either PAR1-activating hexapeptide (PAR1AP) or convulxin was unaffected. This was confirmed by PLT aggregation studies induced with collagen, PAR1AP, and ristocetin at two different agonist concentrations. Finally, UV-C slightly increased lactic acid production rates, resulting in significantly decreased pH on Days 5 and 7, but never dropped below 7.2.


CONCLUSIONS
UV-C pathogen inactivation treatment slightly but significantly increases PLT activation markers but does not profoundly influence activatability nor aggregation. The treatment does, however, attenuate thrombus formation kinetics in vitro in microfluidic flow chambers, especially after storage.
Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium.
Britt
B
Van Aelst
Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium.
Rosalie
R
Devloo
Blood Service of the Belgian Red Cross-Flanders, Mechelen, Belgium.|Department of Public Health and Primary Care, Catholic University of Leuven, Leuven, Belgium.|Faculty of Medicine and Health Sciences, University of Ghent, Ghent, Belgium.
Philippe
P
Vandekerckhove
Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium.|Blood Service of the Belgian Red Cross-Flanders, Mechelen, Belgium.|Faculty of Medicine and Health Sciences, University of Ghent, Ghent, Belgium.
Veerle
V
Compernolle
Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium.
Hendrik B
HB
Feys
D017304:Annexin A5 / Q000378:metabolism; D001777:Blood Coagulation / Q000187:drug effects / Q000528:radiation effects*; D001792:Blood Platelets / Q000378:metabolism*; D058731:Blood Safety / Q000009:adverse effects; D003094:Collagen / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016023:Integrins / Q000378:metabolism*; D007700:Kinetics; D019007:P-Selectin / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
D017304:Annexin A5; D016023:Integrins; D019007:P-Selectin; D003094:Collagen