Comparative in vitro evaluation of apheresis platelets stored with 100% plasma or 65% platelet additive solution III/35% plasma and including periods without agitation under simulated shipping conditions

Influence of apheresis collection device and container on the storage properties of platelets in 90% PAS-5/10% plasma

BACKGROUND

The storage properties of apheresis platelets suspended in the experimental additive solution PAS-5 and 10% plasma may be affected by the collection instrument or storage container.

METHODS AND EXPERIMENTAL DESIGN

The same consenting 12 donors provided A or T platelets with concurrent plasma on four occasions in 100% plasma. Following collection and resting, the platelets were centrifuged, and plasma was expressed and resuspended in PAS-5 to yield units with 10% plasma. Platelets were either maintained in the original storage container or transferred to another of the manufacturer's storage containers. On days 1, 5 and 7, units were assayed for an array of in vitro tests.

RESULTS

Average unit volume, yield and percent plasma was 291±11 mL, 3.7±0.4×10¹¹, and 10.3±0.7%, respectively, and were comparable between collections with either of the apheresis instruments and stored with either of the manufacturer's containers. Day 1 platelet activation (CD62P+) was 40±22% and was similar in either of the collection instruments or containers. Except for pH (days 1, 5), CO₂ (days 1, 5, 7), and extent of shape change (day 5), every other in vitro parameter was similar between apheresis platforms or the manufacturer's container. pH values of all units on all days of storage were ≥6.8, except one unit that was collected on T and stored in an A container, which had pH values of 6.8 and 5.7 on days 5 and 7, respectively.

DISCUSSION

Storage of platelets suspended in PAS-5 with 10% plasma is feasible in the original manufacturer's container for seven days. Based on CO₂ levels, T containers have greater gas exchange than A containers.

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.

Platelets: handle with care

Platelets are delicate cells that require careful handling between collection, preparation and transfusion. This review addresses practical questions relating to platelet concentration, resting time after collection, total time and number of periods without agitation and temperature. The bags in which platelets are stored are made from gas-permeable plastic to allow sufficient oxygen for the platelets to maintain aerobic respiration. Manufacturers have assigned limits for platelet content and concentration, and these must not be exceeded. There is no strong evidence for or against the resting of platelets post-collection and pre-agitation, but platelets should not be over-wrapped during this period as this compromises gas exchange; a short rest period of up to 1 h may allow the separation of minor aggregates. It is necessary to transport platelet concentrates (e.g. from manufacturing site to hospital), but these periods without gas exchange must be limited to avoid excessive damage to the platelets. Current data support a total of 24 h of transportation per component but with no individual period lasting more than 8 h. Platelets need to be stored at 20-24 °C based on evidence that colder storage leads to irreversible changes on the platelet membrane, resulting in phagocytosis of the platelets following transfusion. Storage at warmer temperatures may lead to an increase in bacterial risk. On the basis of this review, the UK Guidelines for Blood Transfusion Services have been updated to ensure that platelets are handled in the most appropriate way to ensure that efficacious components are provided for patients.

Evaluation of in vitro storage properties of apheresis platelets suspended in a bicarbonate-containing additive solution with low levels of plasma and stored with a 24-hour interruption of agitation

BACKGROUND AND OBJECTIVES

PLT additive solutions (PAS) are useful for reducing the frequency and/or severity of plasma-associated transfusion reactions. A new PAS solution, PAS-5, containing 5% plasma, maintains in vitro PLT properties during 7-day storage. Periods with interruption of agitation (IA) ≤24 h routinely occur during PLT shipment and do not usually compromise platelet quality. The aim of the study was to evaluate the properties of PLTs stored for 7 days in 95% PAS-5/5% plasma subjected to a 24-h IA.

MATERIALS AND METHODS

Double apheresis Amicus units (n = 12) were collected using a manual PAS-5 addition to hyperconcentrated PLTs. PLT units were equally divided in two containers. Control and test PLTs were stored with continuous agitation at 20-24°C except for 24-h IA period for test units between days 2-3.

RESULTS

During storage, levels of glucose, lactate, mitochondrial membrane potential and aggregation significantly differed in test units compared to those of control. The pH levels of test PLTs were less than those of control units with 7/12 test units having pHs <6·2 on Day 7 compared to 1/12 control units. Morphology score, GP1bα expression, ESC values, superoxide production were also less, and activation was greater in test PLTs than those of control. All other parameters were similar between test and control units.

CONCLUSION

PLTs stored in PAS-5 solution containing 5% plasma with a 24-h IA results in marked decrements in many in vitro PLT quality parameters during 7-day storage.