The impact of refrigerated storage of UVC pathogen inactivated platelet concentrates on in vitro platelet quality parameters

Abstract

Background and Objectives Refrigeration (cold‐storage) of pathogen inactivated (PI) platelet components may increase the shelf‐life and safety profile of platelet components, compared to conventional room‐temperature (RT) storage. Whilst there is substantial knowledge regarding the impact of these individual treatments on platelets, the combined effect has not been assessed. Materials and methods Using a pool‐and‐split study design, paired buffy‐coat derived platelets in 70% platelet additive solution (SSP+; MacoPharma) were left untreated or PI‐treated using the THERAFLEX UV‐Platelets System (UVC; MacoPharma). Units from each pair were split and stored at room temperature (20–24°C) or cold‐stored (2–6°C) to yield RT, cold, RT‐UVC and cold‐UVC study groups (n = 8 in each group). In vitro quality and function was tested over 9 days. Results Cold‐storage of UVC‐treated platelets reduced glycolytic metabolism (glucose consumption and lactate production) compared to RT‐UVC units. Cold‐UVC platelets demonstrated complete abrogation of HSR by day 5, increased externalisation of phosphatidylserine (annexin‐V binding) and activation of the GPIIb/IIIa receptor (PAC‐1 binding) above the levels observed with the individual treatments. Aggregation responses (ADP and collagen) were enhanced in the cold‐UVC platelets compared to both RT groups, but this was primarily mediated by cold‐storage. Haemostatic function, as measured using TEG, was similar between the groups. Conclusion Cold‐storage of UVC‐treated platelets reduced PI‐induced acceleration of glycolytic metabolism. However, combining cold‐storage and UVC‐treatment resulted in additional phenotypic changes compared to each treatment individually. Further work is required to understand the impact of these changes in clinical efficacy.

Extended storage of thawed platelets: Refrigeration supports postthaw quality for 10 days

“…The supernatants were collected and stored at −80°C until analysis. The concentration of glucose and lactate was measured from the platelet supernatant with commercially available kits, as previously described 12 …”

“…The concentration of glucose and lactate was measured from the platelet supernatant with commercially available kits, as previously described. 12 The platelet phenotype was characterized by flow cytometry (FACSCanto II, Becton Dickinson, Franklin Lakes, New Jersey), with a total of 10 000 events collected. The platelet population was established based on forward scatter (FSC) and side scatter (SSC) properties.…”

Cryopreservation of UVC pathogen‐inactivated platelets

“…The pH of PLT components was measured using a pH meter at room temperature (20–24°C) immediately after sampling (Seven Excellence Multiparameter, Mettler). The glucose and lactate concentration were measured from the PLT supernatant, as previously described …”

The immune potential of ex vivo stored platelets: a review

“…Platelet refrigeration results in significant morphological change and more pronounced expression of activation markers in comparison to room temperature stored components [58–61]. However, alterations to the immune characteristics of platelets induced by refrigeration are largely uncharacterized (Tables 1 & 2).…”