Thrombin generation and coagulation factor content of thawed plasma and platelet concentrates

Effect of bedside filtration on aggregates from cold-stored whole blood-derived platelet-rich plasma and apheresis platelet concentrates

BACKGROUND

The current approach to manufacture cold-stored platelets (CSP) replicates that of room temperature-stored platelets (RSP). However, this production method is associated with aggregate formation in CSP, a major pitfall that leads to significant wastage. We hypothesized that isolating platelets from whole blood as platelet-rich plasma (PRP) and storing them at a lower concentration reduces aggregates and that conventional bedside transfusion filtration removes CSP aggregates.

METHODS

We collected platelets from healthy humans by apheresis (AP) and by phlebotomy, from which we generated platelet-rich plasma (PRP). We split each AP and PRP platelets into two equal aliquots, storing one at 22°C (RT-PRP and RT-AP) and the other at 4°C (4C-PRP and 4C-AP). We evaluated platelets on day 0 and day 7 of storage. After storage, we measured platelet counts, aggregates, and other key characteristics before and after filtration by a bedside filter.

RESULTS

After storage, the 4C-AP platelet counts decreased significantly. 4C-PRP preserved glucose better and prevented a significant increase in lactate contrary to 4C-AP. Filtration led to significantly lower platelet counts in both 4C-PRP and 4C-AP but not in their RT counterparts. Post filtration, we observed 50% fewer aggregates only in 4C-AP, whereas 4C-PRP showed an unexpected but significant increase in aggregates. Testing confirmed activation during storage but filtration did not further activate platelets.

CONCLUSION

We provide evidence that 4C-PRP is an alternative to 4C-AP and that bedside filters reduce aggregates from 4C-AP. Further studies are needed to evaluate the hemostatic potential of 4C-PRP and the management of aggregates.

A Comparison of Growth Factors and Cytokines in Fresh Frozen Plasma and Never Frozen Plasma

BACKGROUND

Fresh frozen plasma (FFP) contains proinflammatory mediators released from cellular debris during frozen storage. In addition, recent studies have shown that transfusion of never-frozen plasma (NFP), instead of FFP, may be superior in trauma patients. We hypothesized that FFP would have higher levels of inflammatory mediators when compared to NFP.

MATERIALS AND METHODS

FFP (n = 8) and NFP (n = 8) samples were obtained from an urban, level 1 trauma center blood bank. The cytokines in these samples were compared using a Milliplex (Milliplex Sigma) human cytokine magnetic bead panel multiplex assay for 41 different biomarkers.

RESULTS

Growth factors that were higher in NFP included platelet-derived growth factor-AA (PDGF-AA; 8.09 versus 108.00 pg/mL, P < 0.001) and PDGF-AB (0.00 versus 215.20, P= 0.004). Soluble CD40-ligand (sCD40L), a platelet activator and pro-coagulant, was higher in NFP (31.81 versus 80.45 pg/mL, P< 0.001). RANTES, a leukocyte chemotactic cytokine was higher in NFP (26.19 versus 1418.00 pg/mL, P< 0.001). Interleukin-4 (5.70 versus 0.00 pg/mL, P= 0.03) and IL-8 (2.20 versus 0.52 pg/ml, P= 0.03) levels were higher in were higher in FFP.

CONCLUSIONS

Frozen storage of plasma may result in decrease of several growth factors and/or pro-coagulants found in NFP. In addition, the freezing and thawing process may induce release of pro-inflammatory chemokines. Further studies are needed to determine if these cytokines result in improved outcomes with NFP over FFP in transfusion of trauma patients.

Effect of storage of plasma in the presence of red blood cells and platelets: re-evaluating the shelf life of whole blood

BACKGROUND

There is renewed interest in administering whole blood (WB) for the resuscitation of patients with bleeding trauma. The shelf life of WB was established decades ago based on the viability of red blood cells. However, plasma quality during WB storage is not established.

STUDY DESIGN AND METHODS

White blood cell- and platelet-reduced WB (WB-PLT) was prepared using standard processes and compared to WB processed using a platelet-sparing WBC reduction (WB + PLT) filter. WB (± PLT) was held at 2 to 6°C for 35 days alongside control units of red blood cells (RBCs) in saline, adenine, glucose, and mannitol and liquid plasma. A series of assays explored the coagulation potential and RBC quality.

RESULTS

While fibrinogen and α2-antiplasmin remained unaffected by storage, other factors varied between components or over time at 2 to 6°C. At 14 days factor V, factor VII, α₂ -antiplasmin and free protein S antigen remained on average greater than 0.50 IU/mL or 50%, as appropriate, in WB ± PLT. Factor VIII was on average 0.49 IU/mL in WB+PLT, and 0.56 IU/mL for WB-PLT. Free protein S activity decreased significantly in all arms but remained on average greater than 40% at Day 14. Contact activation was not demonstrated before Day 14. Thrombin generation in plasma remained relatively stable to Day 35 in all arms.

CONCLUSIONS

Clotting factor activity remained at or above a mean of 0.5 IU/mL, or 50%, at Day 14 for factor V, factor VII, factor VIII, free protein S, fibrinogen, and α2-antiplasmin in all arms. Further data on platelet function in WB+PLT is needed to inform its shelf life.

Thrombin generation potential and clot-forming capacity of thawed fresh-frozen plasma, plasma frozen within 24 h and solvent/detergent-treated plasma (octaplasLG® ), during 5-day storage at 1-6°C

To enable rapid availability of plasma in emergency situations, the shelf-life of thawed fresh-frozen plasma (FFP) has been extended from 24 h to 5 days. The aim of this study was to evaluate the thrombin generation (TG) potential and clot-forming ability during 5 days of refrigerated storage of thawed FFP, plasma frozen within 24 h and solvent/detergent-treated plasma octaplasLG® . During storage for 5 days, TG capacity decreased significantly over time, and rotational thromboelastometry showed significantly prolonged clotting times. However, the stability studies confirmed comparable in vitro haemostatic potentials of all three thawed plasma products at day 5.

Characterization of biologic response modifiers in the supernatant of conventional, refrigerated, and cryopreserved platelets

BACKGROUND

Alternatives to room temperature storage of platelets (PLTs) are of interest to support blood banking logistics. The aim of this study was to compare the presence of biologic response modifiers (BRMs) in PLT concentrates stored under conventional room temperature conditions with refrigerated or cryopreserved PLTs.

STUDY DESIGN AND METHODS

A three-arm pool-and-split study was carried out using buffy coat-derived PLTs stored in 30% plasma/70% SSP+. The three matched treatment arms were as follows: room temperature (20-24°C), cold (2-6°C), and cryopreserved (-80°C with DMSO). Liquid-stored PLTs were tested over a 21-day period, while cryopreserved PLTs were tested immediately after thawing and reconstitution in 30% plasma/70% SSP+ and after storage at room temperature.

RESULTS

Coagulation factor activity was comparable between room temperature and cold PLTs, with the exception of protein S, while cryopreserved PLTs had reduced Factor (F)V and FVIII activity. Cold-stored PLTs retained α-granule proteins better than room temperature or cryopreserved PLTs. Cryopreservation resulted in 10-fold higher microparticle generation than cold-stored PLTs, but both groups contained significantly more microparticles than those stored at room temperature. The supernatant from both cold and cryopreserved PLTs initiated faster clot formation and thrombin generation than room temperature PLTs.

CONCLUSION

Cold storage and cryopreservation alter the composition of the soluble fraction of stored PLTs. These differences in coagulation proteins, cytokines, and microparticles likely influence both the hemostatic capacity of the components and the auxiliary functions.

Quality Assessment of Established and Emerging Blood Components for Transfusion

Blood is donated either as whole blood, with subsequent component processing, or through the use of apheresis devices that extract one or more components and return the rest of the donation to the donor. Blood component therapy supplanted whole blood transfusion in industrialized countries in the middle of the twentieth century and remains the standard of care for the majority of patients receiving a transfusion. Traditionally, blood has been processed into three main blood products: red blood cell concentrates; platelet concentrates; and transfusable plasma. Ensuring that these products are of high quality and that they deliver their intended benefits to patients throughout their shelf-life is a complex task. Further complexity has been added with the development of products stored under nonstandard conditions or subjected to additional manufacturing steps (e.g., cryopreserved platelets, irradiated red cells, and lyophilized plasma). Here we review established and emerging methodologies for assessing blood product quality and address controversies and uncertainties in this thriving and active field of investigation.

Thrombin generation, ProC(®)Global, prothrombin time and activated partial thromboplastin time in thawed plasma stored for seven days and after methylene blue/light pathogen inactivation

BACKGROUND

Methylene blue pathogen inactivation and storage of thawed plasma both lead to changes in the activity of several clotting factors. We investigated how this translates into a global loss of thrombin generation potential and alterations in the protein C pathway.

MATERIALS AND METHODS

Fifty apheresis plasma samples were thawed and each divided into three subunits. One subunit was stored for 7 days at 4 °C, one was stored for 7 days at 22 °C and one was stored at 4 °C after methylene blue/light treatment. Thrombin generation parameters, ProC(®)Global-NR, prothrombin time and activated partial thromboplastin time were assessed on days 0 and 7.

RESULTS

The velocity of thrombin generation increased significantly after methylene blue treatment (increased thrombin generation rate; time to peak decreased) and decreased after storage (decreased thrombin generation rate and peak thrombin; increased lag time and time to peak). The endogenous thrombin generation potential remained stable after methylene blue treatment and storage at 4 °C. Methylene blue treatment and 7 days of storage at 4 °C activated the protein C pathway, whereas storage at room temperature and storage after methylene blue treatment decreased the functional capacity of the protein C pathway. Prothrombin time and activated partial thromboplastin time showed only modest alterations.

DISCUSSION

The global clotting capacity of thawed plasma is maintained at 4 °C for 7 days and directly after methylene blue treatment of thawed plasma. Thrombin generation and ProC(®)Global are useful tools for investigating the impact of pathogen inactivation and storage on the clotting capacity of therapeutic plasma preparations.

Thawed and liquid plasma--what do we know?

There is increasing interest in the use of liquid or frozen plasma thawed and stored for extended periods (>24 h) to reduce wastage and to improve rapid availability of plasma in massive transfusion protocols advocating the early use of plasma in trauma by some centres. There is now a body of studies that have assessed individual coagulation factors during storage of thawed plasma. These show that factor VIII (FVIII) is the worst affected factor and that its activity is mainly lost during the first 24 h following thawing. However, for most factors studied, there is a continual decline during further storage. The few studies that have assessed thrombin generation in thawed plasma have shown variable results. Extended storage of plasma is associated with an increase in levels of DEHP in the component and could theoretically increase the risk of bacterial contamination, although the latter does not appear to have been an issue in countries that have adopted the use of thawed plasma. There are no clinical studies relating to the efficacy of extended-thawed plasma, and therefore, the potential reduction in its efficacy must be balanced with the clinical need for the component.