Storage of platelets in additive solutions: Effects of phosphate

Background and Objectives: In a previous study, low adenine nucleotide leve ls and a reduced rate of glycolysis were found in platelet concentrates (PC s) prepared by apheresis and stored in a platelet additive solution (PAS). Our objective was to investigate whether the use of PAS with or without pho sphate can influence platelet metabolism in a similar way. Materials and Me thods: The in vitro effects of storage in either plasma or a PAS (T-Sol or PAS-III, both containing citrate, acetate and sodium chloride, PAS-Ill cont aining also phosphate) of buffy-coat-derived pooled platelet concentrates ( BC-PCs) and apheresis platelets were investigated. The use of PAS implies i nclusion of some plasma (20 or 35%). Paired studies over 7 days included in vestigation of cell counts, pH, PO2, PCO2, bicarbonate, glucose, lactate, a denine nucleotides, and extracellular adenylate kinase activity as a marker for disintegration of platelets. The expected concentration of phosphate i n T-Sol is 0.6-1.8 mmol/l (with CPD plasma) and 0.2-0.6 mmol/l (with ACD pl asma), and in PAS-III, 15-25 mmol/l (calculated values). Results: BC-PCs we re compared during storage in 35% CPD plasma and 65% PAS (T-Sol or PAS-III) (experiment 1), or alternatively 20% CPD plasma and 80% PAS (T-Sol or PAS- III) (experiment 3). In both studies, PAS-III shows similar and significant ly higher rates of glycolysis in terms of consumption of glucose (0.06 vs. 0.04 mmol/day/10(11) platelets) and production of lactate (0.11 vs. 0.07 mm ol/day/10(11) platelets) compared with T-Sol. Levels of pH and adenine nucl eotides were similar when 35% plasma was used. With only 20% plasma, signif icantly higher levels of adenine nucleotides were found with PAS-III compar ed to T-Sol. The storage of apheresis platelets in 35% ACD plasma and 65% P AS (either T-Sol or PAS-III) (experiment 5) gave significantly higher value s for PAS-III compared to T-Sol with regard to consumption of glucose (0.08 vs. 0.06 mmol/day/10(11) platelets), production of lactate (0.14 vs. 0.11 mmol/day/10(11) platelets) and adenine nucleotide levels. Conclusion: With respect to apheresis PCs stored in media containing ACD plasma, our results suggest that the differences found are related to the concentration of pho sphate. The results for BC-PCs stored in media containing CPD plasma sugges t that PAS-III is preferable to T-Sol as the PAS at plasma concentrations b elow 35%. The mechanism behind the phenomena observed with BC-PCs is not kn own. Copyright (C) 2000 S, Karger AG, Basel.