Effects of Mirasol PRT treatment on storage lesion development in plasma-stored apheresis-derived platelets compared to untreated and irradiated units

BACKGROUND: The aim of this study was to examine the effects of a new riboflavin-based pathogen reduction technology (PRT), the Mirasol PRT process (Navigant Biotechnologies) on platelet (PLT) storage lesion development. STUDY DESIGN AND METHODS: A three-arm in vitro study was conducted comparing cell quality of apheresis PLTs (n = 12 each) treated with Mirasol PRT (M) to untreated (C) and gamma-irradiated units (X) collected from the same donors and stored for up to 7 days under equal conditions. RESULTS: PLT count, lactate dehydrogenase, and K(+) release of M units were not significantly different from C units, indicating retention of cell integrity during storage. The immediate effect (Day 1) of PRT treatment was a significant decrease in hypotonic shock response (M, 80.6 +/- 7.8% vs. 89.2 +/- 8.3%) and aggregation (M, 85.7 +/- 15.2%/min vs. 111.8 +/- 31.5%/min) as well as a significant acceleration of mitochondrial membrane depolarization (M, 1.43 +/- 0.44% vs. 0.91 +/- 0.27%) and P-selectin expression (M, 38.4 +/- 13.8% vs. 15.8 +/- 7.7%) resulting in lower swirl scores on Day 5 (1.5 +/- 0.7 vs. 2.7 +/- 0.4). Significantly higher glucose consumption (60 +/- 13 nmol/10(12) cells/hr vs. 31 +/- 9 nmol/10(12) cells/hr) and lactate production rates (82 +/- 17 nmol/10(12) cells/hr vs. 40 +/- 8 nmol/10(12) cells/hr) caused higher acidity in treated units (pH on Day 5, 6.97 +/- 0.15 vs. 7.42 +/- 0.10). After PRT treatment, oxidative metabolism was still active and, from calculation of oxygen consumption (1.09 +/- 0.23 nmol/min/10(9) PLTs), appeared to be up regulated relative to controls (0.76 +/- 0.27 nmol/min/10(9) PLTs). CONCLUSION: Although storage variables clearly showed the effects of PRT treatment, apheresis PLTs treated with Mirasol PRT retained cell quality during 5 days of storage without loss of mitochondria-based oxidative respiration.