Annexin V Release and Transmembrane Mitochondrial Potential during Storage of Apheresis-Derived Platelets Treated for Pathogen Reduction

Abstract

Background: In vitro function of stored platelet (PLT) con-centrates was analyzed after applying two different techniques of pathogen reduction technology (PRT) treatment, which could increase cellular injury during processing and storage. Methods: Nine triple-dose PLT apheresis donations were split into 27 single units designated to riboflavin-UVB (M) or psoralen-UVA (I) treatment or remained untreated (C). Throughout 8 days of storage, samples were analyzed for annexin V release, the mitochondrial transmembrane potential (ΔΨ) and some classical markers of PLT quality (pH, LDH release, hypotonic shock response (HSR)). Results: PLT count and LDH release of all units maintained initial ranges. All units exhibited a decrease in pH and HSR and an increase in annexin V release and ΔΨ disruption. Notably, throughout the entire storage period, annexin V release re-mained lowest in M units. Throughout 7 days of storage, M units remained comparable to C units (p > 0.05), whereas inferior values were observed with I units. Here, differences to C units reached significance by day 1 (pH: p < 0.0001), day 5 (annexin V release: p < 0.014), and day 7 (HSR, ΔΨ: p ≤ 0.003). After PRT treatment, annexin V release and ΔΨ disruption were significantly (p < 0.001) correlated with pH and HSR. Conclusion: During storage, all units showed a de-crease in HSR and an increase in acidity, annexin V release and ΔΨ disruption. While M units remained comparable to C units, I units demonstrated significantly inferior values dur-ing terminal storage. This could have resulted from differences in PRT treatment or simply be due to differences in storage media and should be analyzed for clinical relevance in future investigations.