Phänotypische Veränderungen beeinflussen nicht die Fähigkeit zur Wiederherstellung der Hämostase in kalt gelagerten Thrombozyten
Nina Wolska (Tübingen / DE), Brigitte Weidenthaler (Tübingen / DE), Julian Dürr (Tübingen / DE), Karoline Weich (Tübingen / DE), Irene Marini (Tübingen / DE), Tamam Bakchoul (Tübingen / DE)
Platelet concentrates (PCs) are used to treat or prevent bleeding. The current standard room temperature (RT) storage is allowed only for 4-5 days due to high risk of bacterial contamination. We investigate the molecular changes in platelet concentrates stored at RT and 4°C and asses their performance in in vitro functional tests.
Apheresis platelet concentrates were separated into 2 equivalent, GMP conforming bags kept at RT and the other at 4°C, under agitation. PCs were quality controlled according to clinical standard. The tests
were performed using the PCs or PCs in a model of thrombocytopenia. Multicolour flow cytometry was used to assess platelet activation and metabolic status. Aggregometry was performed, as well as thromboelastography. A flow system mimicking the physiological flow conditions linked with real-time imaging was used to assess the clot forming ability, morphology and composition of the clots.
All PCs were valid at both temperatures according to the quality control measures. Cold storage maintains higher platelet counts. The cold stored platelets show upregulated PS exposure, spontaneous degranulation, and slight increase of spontaneously aggregatory phenotype, but do not display lower viability. The platelet ability to degranulate upon stimulation is unaffected, the activation of integrins mediated through P2Y12 receptor is lowered, but increased upon PAR1 stimulation. Spontaneous aggregation is lowered, but below 15% for both temperatures. PC aggregation shows no significant difference when stimulated with collagen or ristocetin, but improved at arachidonic acid (AA), ADP, and TRAP-6 stimulation. The potential to restore haemostasis is improved in case of AA, collagen, ADP, and
TRAP-6. Thromboelastography shows no change. Experiments performed in conditions of physiological flow show no comparable ability to form thrombi. In all tests the reactivity of PC or PC applied in a model of thrombocytopenia remained within the physiological values, with no indication of thrombotic phenotype.
Cold-induced effects on platelet functions during storage time are significant on the molecular level, but do not impair the haemostatic functionality of cold stored platelet concentrates. Cold storage of platelet concentrates is a promising strategy to prolong the storage time, improve the platelet survival and reduce the risk of bacterial infection post transfusion, without incising the thrombotic risk.
No conflict of interest to declare.