The effect of 24 h resting of old PCs at 22-24°С in permeable bags on in vitro platelet parameters

Background: During transporting periods, platelet (PLT) concentrates (PCs) usually undergo a long period without agitation. Whether this interruption, improves quality and viability, or has deleterious effect at 72 h stored PCs, is here investigated. The aim of our study is to investigate effect of metabolic resting (24 h interruption of agitation) versus continue agitation of 72 h-stored PCs (old), prior to transfusion in the blood bank of Tehran.

Study design and methods: PCs were prepared using the platelet-rich plasma (PRP) method and stored in the permeable bags in the shaker/incubator, for 72 h at 20-24°C. Then by simply stopping the agitator, PCs remained at stationary condition without agitation for 24 h (WA24h) before sampling. In vitro measurements of PLT quality were carried out just after the termination of interruption period, and the results were compared with continuously agitated platelet within the same day (designated as control group, CA). In vitro variables which are measured were pH, Platelet count, swirling, Ristocetin-induced aggregation (GPIb-related function), LDH, PF4 release and P-selectin expression (activation marker).

Results: Compared with control group, the mean platelets PF4 release and P-selectin expression showed no significant differences (p=0.101, p=0.739 respectively). The mean level of pH was not significant (p=0.156); WA24h (7.12±0.14) and CA (7.17±0.11). Also Ristocetin-induced aggregation study showed significant differences (p=0.0281) between CA (76.6±3.2) and WA24h (62.69±21.43). Other in vitro variables between CA and WA groups including swirling, Platelet count and LDH showed no significant differences after 72 h of storage.

Conclusions: We observed that 24 h resting of old PCs (WA24h) at 22-24°С in permeable bags preserved pH, swirling, LDH, Ristocetin-induced aggregation and platelet's activation as good as control group after 72 h of storage.