Impact of cold storage on platelets treated with Intercept pathogen inactivation

Abstract

BACKGROUND: Pathogen inactivation and cold or cryopreservation of platelets (PLTs) both significantly affect PLT function. It is not known how PLTs function when both are combined. STUDY DESIGN AND METHODS: Standard PLTconcentrates (PCs) were compared to pathogeninactivated PCs treated with amotosalen photochemical treatment (AS-PCT) when stored at room (RT, 22 C), cold (4 C, n = 6), or cryopreservation (−80 C, n = 8) temperatures. The impact of alternative storage methods on both arms was studied in flow cytometry, light transmittance aggregometry, and hemostasis in collagen-coated microfluidic flow chambers. RESULTS: Platelet aggregation of cold-stored AS-PCTPLTs was 44% AE 11% compared to 57% AE 14% for coldstored standard PLTs and 58% AE 21% for RT-stored AS-PCT PLTs. Integrin activation of cold-stored AS-PCT PLTs was 53% AE 9% compared to 77% AE 6% for cold-stored standard PLTs and 69% AE 13% for RT-stored AS-PCT PLTs. Coagulation of cold-stored AS-PCT PLTs started faster under flow (836 AE 140 sec) compared to cold-stored standard PLTs (960 AE 192 sec) and RT-stored AS-PCT PLTs (1134 AE 220 sec). Fibrin formation rate under flow was also highest for cold-stored AS-PCT PLTs. This was in line with thrombin generation in static conditions because cold-stored AS-PCT PLTs generated 297 AE 47 nmol/L thrombin compared to 159 AE 33 nmol/L for cold-stored standard PLTs and 83 AE 25 nmol/L for RTstored AS-PCT PLTs. So despite decreased PLT activation and aggregation, cold storage of AS-PCT PLTs promoted coagulation. PLT aggregation of cryopreserved AS-PCT PLTs (23% AE 10%) was not significantly different from cryopreserved standard PLTs (25% AE 8%). CONCLUSION:This study shows that cold storage of AS-PCT PLTs further affects PLT activation and aggregation but promotes (pro)coagulation. Increased procoagulation was not observed after cryopreservation. ABBREVIATIONS: AS-PCT = amotosalen photochemical treatment; ETP = endogenous thrombin potential; MP = microparticle; PC(s) = platelet concentrate(s); PS = phosphatidylserine; RT = room temperature; TF = tissue factor. From the

Effects of Intercept pathogen reduction treatment on extended cold storage of apheresis platelets

“…In our study, Intercept treatment did not lead to an increase in P‐selectin expression compared to normal cold PLT storage. While previous groups have reported increased PLT PS expression and cell death due to Intercept treatment, 37,41 our work observed significantly increased PS expression (compared to same‐day control) in Amicus/plasma samples only at Day 21 of storage, whereas increased plasma membrane breakdown was observed at Day 14 and 21 of storage for Trima/plasma and Amicus/plasma samples, respectively. Instead, the increased PS expression was reflective of cold storage than Intercept treatment.…”

“…While Intercept treatment did not dramatically alter ETP, it did result in shortened lag times and increased peak thrombin levels after 7 days of storage. A similar finding was observed in whole blood–derived PLT concentrates that were Intercept‐treated and cold stored for 5 days 37 …”

Platelet Biochemistry and Morphology after Cryopreservation

“…However, aggregation is detected with strong agonists like thrombin or collagen added at high concentrations [22]. Furthermore, when several agonists are combined like thrombin receptor agonist peptide 6 (TRAP-6) with ADP and epinephrine substantial aggregation is detected in cryopreserved platelets albeit two-to three-fold lower than in RT stored platelets [17,37]. Ristocetin induced agglutination requires less outside-in signaling to crosslink platelets via GPIbα and VWF compared to agonist induced aggregation which crosslinks platelets via fibrinogen and integrin α IIb β 3 .…”

“…Foremost, the platelet concentrate itself varies between studies because platelet separation methods are different throughout the globe. Resulting variables are platelet concentration, platelet additive solution, type of storage bag and pathogen inactivation [37].…”

“…Comparison was with paired samples before cryopreservation. The methods used have been described in detail before[17,37,40]. (A) The percentage of GPIbα normal platelets was determined by CD42b measurements in flow cytometry.…”