PLTs stored under automated TC conditions have improved in vivo recovery and improved results for a number of in vitro measures compared to CT-PLTs.

Background and ObjectivesPlatelets during storage undergo diverse alterations collectively known as the platelet storage lesion, including metabolic, morphological, functional and structural changes. Some changes correlate with activation of p38 mitogen activated protein kinase (p38 MAPK). Another MAPK, extracellular signal-related kinase (ERK), is involved in PLT activation. The aim of this study was to compare the properties of platelets stored in plasma in the presence or absence of p38 and ERK MAPK inhibitors.Materials and MethodsA single Trima apheresis platelet unit (n = 12) was aliquoted into five CLX storage bags. Two aliquots were continuously agitated with or without MAPK inhibitors. Two aliquots were subjected to 48 hours of interruption of agitation with or without MAPK inhibitors. One aliquot contained the same amount of solvent vehicle used to deliver the inhibitor. Platelets were stored at 20–24°C for 7 days and sampled on Days 1, 4, and 7 for 18 in vitro parameters.ResultsInhibition of p38 MAPK by VX-702 leads to better maintenance of all platelet in vitro storage parameters including platelet mitochondrial function. Accelerated by interruption of agitation, the platelet storage lesion of units stored with VX-702 was diminished to that of platelets stored with continuous agitation. Inhibition of ERK MAPK did not ameliorate decrements in any in vitro platelet properties.ConclusionSignaling through p38 MAPK, but not ERK, is associated with platelet deterioration during storage.

Background and Objectives Blood Centre logistics, staffing and donor scheduling may be optimized if pathogen inactivation (PI) of platelets can be delayed until Day 1, but bacteria may rapidly grow during this time. This study evaluates bacterial PI performed 24 and 30 h after collection.Materials and Methods PAS-3 platelet units were collected on the Amicus and subsequently inoculated (3-53 CFU/unit) with 1of 5 transfusion relevant bacterial species (n = 3/organism). Units were then stored for either 24 -0Á3 or 30 -0Á3 h at 20-24°C with agitation, subsequently treated with amotosalen and UVA, and stored for 7 days. Samples were taken before and after inactivation, on Days 2, 5 and 7 for BacT/ALERT testing, and on Days 5 and 7 for plate counts.Results All samples from units taken prior to inactivation either demonstrated positive plate culture counts, or, in untreated positive controls, were culture-positive during storage. All contaminated units treated with amotosalen and UVA 24 after inoculation were culture-negative on all days tested. With inactivation performed 30 h following inoculation, one of 15 units (1-of-3 replicates) was culture-positive with Klebsiella pneumonia (1 9 10 9 CFU/ml) by Day 5.Conclusion Photochemical treatment did not inactivate 1 of 15 units to sterility in apheresis platelets stored in PAS with a 30-h delay between contamination and treatment, but did inactivate 15 of 15 units with a 24-h delay.

BACKGROUND: Sodium citrate has become the preferred anticoagulant used for apheresis collection and has been included in commercial platelet additive solutions (PASs) since PAS-II. It was suggested that citrate be included in PASs to prevent spontaneous aggregation. Reports in cell lines and cord blood have demonstrated that concentrations of citrate present in PAS formulations (10 mM) cause apoptosis. We evaluated whether the removal of citrate from PAS-III could improve platelet storage. STUDY DESIGN AND METHODS: Study 1 evaluatedthe effects of a citrate dose response on the storage of platelets in 65% PAS containing sodium chloride, sodium acetate, and phosphate. Study 2 compared the cell quality and function of platelets stored in 65% citrate-free PAS-III or PAS-III containing 10 mM of citrate. Measurements included cell count, blood gases, flow cytometry analysis of surface activation markers, and aggregation. RESULTS: Study 1 identified that inclusion of citrate in PAS resulted in a dose-dependent increase in glucose utilization, lactate formation, P-selectin expression, phosphatidylserine (PS) exposure, and reactive oxygen species (ROS) formation. Study 2 showed similar results in which platelets stored in citrate-free PAS-III benefited through better maintenance of glucose utilization with less lactate production, P-selectin expression, PS exposure, and ROS formation compared to citratecontaining PAS-III. Platelets stored in citrate-free PAS-III had aggregation responses that were at least 10% greater than those platelets stored in PAS-III. CONCLUSION: Storage of apheresis platelets incitrate-free PAS-III improved multiple storage parameters including glucose utilization, lactate production, Pselection expression, PS exposure, and ROS formation and resulted in a modest increase in aggregation.ABBREVIATIONS: ACD = anticoagulant citrate dextrose solution; ADP = adenosine diphosphate; CPD = citrate-phosphate-dextrose; PASs = platelet additive solutions; PS = phosphatidylserine; ROS = reactive oxygen species; TRAP6 = thrombin receptor activator peptide 6.* Significantly different than Day 5, 0 mM citrate bicarbonate levels; one-way analysis of variance, p = 0.029. † Significantly different than Day 5, 0 mM citrate bicarbonate levels; one-way analysis of variance, p = 0.003.

Addition of either sialidase or p38 MAPK inhibitors do not improve any in vitro parameters of PLTs stored at 4 °C in 100% plasma.