Potentials for prolonging shelf-life of platelets by near infrared low-level light

Platelets are uniquely stored at room temperature, during which they gradually loss their quality owing to deteriorating functions of mitochondria over time. Given the well-documented beneficial effect of near infrared low-level light (LLL) on mitochondrial functions, we explored a potential for LLL to protect mitochondrial function and extend the shelf-life of platelets beyond the current 5 days. We found that exposure of a platelet-containing storage bag to 830 nm light-emitting diode (LED) light at 0.5 J/cm² prior to storage could significantly retain a pH value and viability of the platelets stored for 8 days with improved quality compared to those stored similarly for 5 days in controls. The LLL inhibited reactive oxygen species (ROS) and lactate production, while sustaining ATP synthesis and mitochondrial membrane potential and morphology in the stored platelets. It also sustained aggregation capacity and in vivo survival of stored platelets, concomitant with no significant activation, as suggested by similar CD62p expression and enhanced agonist-induced aggregation and recovery following infusion in the presence compared to absence of LLL treatment. This simple, additive-free, cost-effective, noninvasive approach can be readily incorporated into the current platelet storage system to potentially improve quality of stored platelets.