Summary
It is well known that the function of platelets decreases progressively during storage
of platelet concentrates at room temperature. To investigate this phenomenon in more
detail, we have resuspended platelets that had been stored for 24 h or 72 h in fresh
plasma, and we have measured the aggregation response and the ATP secretion. Conversely,
the effect of plasma in which platelet concentrates (PC) had been stored for 24 h
or 72 h, was tested on fresh platelets. Both the aggregation response to collagen
and ADP and the collagen-induced ATP secretion of stored platelets partially recovered
after incubation with fresh plasma (p <0.05). The same parameters measured with fresh platelets incubated in stored PC-plasma
were found to be significantly reduced in comparison with the response of fresh platelets
in fresh plasma (p <0.05). Finally, platelets were stored in a plasma-free medium, suitable for platelet
storage and the supernatant was tested. This supernatant inhibited the function of
fresh platelets in a storage time-dependent fashion. Boiling of these supernatants
did not change the inhibiting capacities, whereas filtration over active charcoal
did. Analysis of this supernatant revealed AMP and diadenosine tetraphosphate, which
both inhibit platelet function.
These data show that stored platelets release nucleotides that inhibit platelet function
in a reversible manner. This phenomenon may contribute to the decrease of platelet
function during storage and the recovery of platelet function after transfusion.
