Cell viability during platelet storage in correlation to cellular metabolism after different pathogen reduction technologies

BACKGROUND: The objective of this study was to evaluate if pathogen reduction technologies (PRTs) affect platelet (PLT) viability by alteration of PLT metabolism during storage. STUDY DESIGN AND METHODS: Twenty-seven split triple-dose apheresis PLTs were PRT treated using ultraviolet light with either riboflavin-UVB (M) or psoralen-UVA (I) or remained untreated (C). Samples were taken on Days 0, 1, 5, 7, and 8 and analyzed for annexin V release (enzyme-linked immunosorbent assay), mitochondrial enzymatic activity (MTS assay), transmembrane mitochondrial potential (Deltapsi; JC-1 assay), and metabolism based on pH, pO(2), glucose, lactate, and ATP content. RESULTS: During storage, Deltapsi and MTS reduction activity decreased, while annexin V release and acidity increased in all units, more pronounced, however, after PRT treatment, which led to higher lactate accumulation due to acceleration in glycolytic flux. No significant differences were found between C and M, whereas I was significantly different by Day 1 (pH value), Day 5 (annexin V release), and Day 7 (Deltapsi) of storage. Intracellular ATP content remained similar between C and M but was significantly lower in end-stored I units. Cell viability markers of I units were highly correlated with the oxidative pathway, which appeared impaired in I but up regulated in M units. CONCLUSION: PRT treatment using M increased both anoxidative glycolytic flux and oxidative phosphorylation. The I-based technique was associated with an impaired mitochondria-based respiration. During terminal storage, this resulted in significantly lower maintenance of ATP and cell viability. The impact of these findings for storage prolongation or clinical use must await further evaluation.