Platelet glycolytic flux increases stimulated by ultraviolet-induced stress is not the direct cause of platelet morphology and activation changes: possible implications for the role of glucose in platelet storage.

BACKGROUND: Stress-enhanced platelet (PLT) storage lesions include increased glycolysis, discoid-to-sphere morphology change, and spontaneous PLT activation. It is not clear if reduction in glycolysis can alleviate storage lesion development. STUDY DESIGN AND METHODS: Apheresis PLT concentrates were exposed to 17.2 J/mL UV light and 50 microM riboflavin, followed by storage with various concentrations of 2-deoxyglucose (2-DOG) for 5 days. The control had no UV or 2-DOG exposure. RESULTS: Lactate production and glucose consumption were increased significantly to 0.1371 +/- 0.0281 and 0.0724 +/- 0.0151 mmol per 10(12) cells per hour for UV-treated PLTs, respectively, when compared to control samples. UV treatment induced a decline in pH to 6.55 +/- 0.26 for treated PLTs on Day 5, hypotonic shock response (HSR) 33 +/- 25 percent, extent of shape change (ESC) to 3.8 +/- 3.6 percent, swirl 1.0 +/- 1.0 and increased P-selectin expression 85.2 +/- 9.4 percent. Addition of 2-DOG up to 20 mmol per L significantly reduced lactate production to 0.0515 +/- 0.0045 mmol per 10(12) cells per hour (p < 0.05) and glucose consumption to 0.0293 +/- 0.0060 mmol per 10(12) cells per hour and increased pH to 7.35 +/- 0.09 in a dose-dependent manner. 2-DOG, however, had no effects on HSR, ESC, swirl, and P-selectin expression. Furthermore, an exaggeration of UV-stressed PLT aggregation by addition of 2-DOG was also observed. CONCLUSIONS: Increased glycolytic flux is not a direct cause for PLT morphology change and spontaneous activation during storage lesion development. Reduction of glucose utilization may increase PLT loss during storage.

Efficacy of apheresis platelets treated with riboflavin and ultraviolet light for pathogen reduction.

BACKGROUND: Pathogen reduction technologies for platelet (PLT) components offer a means to address continued viral transmission risks and imperfect bacterial detection systems. The efficacy of apheresis PLTs treated with riboflavin (vitamin B2) plus ultraviolet (UV) light (Mirasol, Navigant Biotechnologies) was investigated in a single-blind, crossover study in comparison to untreated PLTs. STUDY DESIGN AND METHODS: Normal subjects (n = 24) donated PLTs by apheresis on two occasions at least 2 weeks apart. Units were randomized to control or test arms, the latter receiving the addition of 28 mL of 500 micromol per L B2 and exposure to 6.2 J per mL UV light. PLTs were stored for 5 days with biochemical and hematologic analyses performed before and after illumination on Day 0 and at the end of storage. An aliquot of each unit was radiolabeled and returned to determine recovery and survival. RESULTS: The PLT content of treated units was maintained from Day 0 (4.1 x 10(11) +/- 0.4 x 10(11)) to Day 5 (4.0 x 10(11) +/- 0.4 x 10(11)). Treatment with B2 plus UV light was associated with an increase in lactate production with concomitant increases in glucose consumption. pH (control, 7.38 +/- 0.07; test, 7.02 +/- 0.10) was well maintained throughout storage. Recovery of treated PLTs (50.0 +/- 18.9%) was reduced from that of control PLTs (66.5 +/- 13.4%); survival was similarly shortened (104 +/- 26 hr vs. 142 +/- 26 h; p < 0.001). CONCLUSIONS: PLTs treated with B2 plus UV light demonstrate some alterations in in vitro measures but retain in vitro and in vivo capabilities similar to pathogen-reduced and licensed PLT components that have been shown to have useful clinical applicability. The recovery, survival, and metabolic properties of Mirasol PLTs should provide sufficient hemostatic support in thrombocytopenia to justify patient clinical trials.