Platelet storage solution effects on the accuracy of laboratory tests for platelet function: a multi-laboratory study

In vitro quality parameters of whole blood-derived platelets pooled using two different platelet pooling sets and stored up to 7 days are similar

BACKGROUND

Increasing the number of collections of whole blood-derived platelets (WBDP) and lengthening the allowable storage time may alleviate platelet (PLT) shortages. There is a need for new PLT pooling sets that can provide acceptable quality on Day 7 of storage.

STUDY DESIGN AND METHODS

This pool-and-split study compared WBDP prepared using the platelet-rich plasma method with the novel IMUGARD WB PLT pooling set and a control pooling set. After pooling and filtration, PLT products were tested on Days 1, 5, and 7. Large volume delayed sampling (LVDS) cultures were taken on Day 2.

RESULTS

The median postfiltration residual white blood cell (rWBC) content was 0.18 million per product (maximum 1.26 million; n = 69) with mean PLT recovery of 88.5 ± 2.8% for the new set and median 0.23 million (maximum 1.83 million) rWBC with 87.5 ± 2.5% recovery for the control. Day 5 mean pH22°C were 7.18 ± 0.12 and 7.13 ± 0.10 for the new and control set, respectively. Day 5 in vitro quality parameters were within 20% between the two pooling sets. The new set Day 7 pH22°C was acceptable (7.07 ± 0.17, 100% ≥ 6.3), and most parameters were within 20% of Day 5 values.

CONCLUSION

WBDP quality for the new pooling set is acceptable across a battery of in vitro tests when stored up to 7 days and meets FDA regulatory criteria. The quality parameters were similar between the new pooling set and the control set on Day 5. This new set is compatible with LVDS.

The Role of Glutamine in the Prevention of Ultraviolet-C-Induced Platelet Activation

Background and Objectives. The primary function of platelets is to prevent bleeding. The use of UV-C light in the treatment of platelets has become a valuable method for preserving the efficacy of platelet concentrates in blood banks. However, its deleterious effect remains, such as the activation of platelets, thus causing the platelets to lose their physiological function. In this study, we intended to demonstrate the impact of UV-C on platelets and how the use of glutamine could mitigate the loss of physiological function of the platelets caused by UV-C. Materials and Methods. This study was conducted using mouse platelets. We assessed calcium signaling using Fura-2 AM incubation and dense granule secretion of the platelets using luminescence assay by measuring ATP. At the molecular level, the activation of integrin using PAC-1 antibody was analyzed. Phosphorylation of immune-precipitated cPLA2 was assessed using a specific antibody. All the experiments were carried out with or without glutamine in the presence of UV-C. Positive and negative controls were used in all experiments to validate the findings. Results. We have demonstrated that physiological and biochemical damage arises as a result of the exposure of platelet concentrate to UV-C and that the use of glutamine could alleviate this damage. Various experiments, thrombus formation, integrin activation, and phosphorylation of cPLA2 were preserved using 50 mM of glutamine in the presence of UV-C, which reduces 50% of platelet viability. Conclusions. Our study demonstrates that the storage of platelet concentrates under the UV-C activates their physiological process and renders them to the thrombus formation, hence decreasing their viability. The presence of a moderate amount of glutamine can alleviate the toxic effect of UV-C, and platelet concentrates could be kept viable for a long time.

Platelet storage in more than 90% additive solution containing glucose and bicarbonate has the potential to increase shelf life

BACKGROUND

Platelet concentrates (PCs) suspended in more than 90% additive solution (AS) are recommended for patients with reactions to platelets stored in plasma. Next-generation AS containing glucose and bicarbonate might enable storage of these PCs for longer than those in current-generation AS, which was therefore evaluated in this study.

STUDY DESIGN AND METHODS

Five buffy coat or apheresis-derived PCs were pooled and split into identical units. All units except the control were centrifuged, the plasma removed and replaced with AS (SSP+, PAS-5, or PAS-G), or resuspended in the same plasma and sampled 96 hours after resuspension for analysis.

RESULTS

Plasma carryover was less than 10%, total protein less than 1 g/unit, and immunoglobulin A levels lower than 0.1 mg/mL for all PCs in AS. The pH of all the platelets during storage was higher than 6.4. PAS containing glucose maintained superior in vitro platelet function during storage compared with those resuspended in SSP+. Compared with storage in SSP+, storage in PAS-5 or PAS-G resulted in better preservation of platelet adenosine triphosphate and hypotonic shock response, lower annexin V binding, and improved mitochondrial membrane potential.

CONCLUSION

Platelets resuspended in PAS-5 and PAS-G maintained in vitro function and metabolism during storage compared with SSP+ platelets. Elevated platelet metabolic activity was noticed in PAS-G, and higher platelet activation was detected with PAS-5. Platelets resuspended in PAS containing glucose has the potential to increase the shelf life of PC in more than 90% AS.

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.

The effect of centrifugation at various g force levels on rheological properties of rat, dog, pig and human red blood cells

Laboratory investigations often require centrifugation of blood samples for various erythrocyte tests. Although there is a lack of data about the effect of centrifugation at various g force levels on erythrocyte rheological properties. We aimed to investigate the effect of a 10-minute centrifugation at 500, 1000 or 1500 g at 15°C of rat, dog, pig and human venous (K3-EDTA, 1.5 mg/ml) blood samples. Hematological parameters, erythrocyte deformability, cell membrane stability, osmotic gradient ektacytometry (osmoscan) and erythrocyte aggregation were determined. Hematological and erythrocyte deformability parameters showed interspecies differences, centrifugation caused no significant alterations. Cell membrane stability for human erythrocytes centrifuged at higher g level showed less decrease in deformability. Osmoscan O min parameter showed slight elevation in dog centrifuged aliquots. Erythrocyte aggregation parameters changed unexpectedly. Rat and dog erythrocyte aggregation indices significantly dropped in centrifuged aliquots. Pig erythrocyte aggregation indices increased significantly after centrifugation. Human erythrocyte aggregation was the most stable one among the investigated species. The used centrifugation protocols caused the largest alterations in erythrocyte aggregation in a controversial way among the investigated species. On the other hand, erythrocyte deformability parameters were stable, cell membrane stability and osmoscan data show minor shifts.

Evaluation of the role of the GPIb-IX-V receptor complex in development of the platelet storage lesion

BACKGROUND AND OBJECTIVES

In mice, loss of sialic acid resulting in shedding of glycoprotein (GP) Ibα and GPV has been linked to platelet survival. The aim of this study was to determine whether loss of sialic acid and the GPIb-IX-V complex contributes to development of the platelet storage lesion (PSL) in human platelet concentrates (PCs).

MATERIALS AND METHODS

PCs (stored in plasma (with or without Mirasol treatment); PAS-C or PAS-E) were stored at room temperature. Flow cytometry was used to monitor membrane expression of the GPIb-IX-V complex, CD62P, surface glycans and PS exposure. The functionality of stored platelets was determined employing aggregometry and ristocetin-induced VWF binding.

RESULTS

Storage time of PCs in blood banks is limited to 7 days. During this time period, a minor but gradually increasing subpopulation of GPIbα-negative platelets was observed. Also, ristocetin-induced VWF binding was impaired in a small population of platelets. Mean surface expression of GPIbα and GPV remained stable until day 9, whereas CD62P expression increased; also a rapid decrease in ADP-induced aggregation was observed for PAS-C, PAS-E and Mirasol-treated PCs. Upon prolonged storage (>9 days), a slow decline in surface expression of GPIbα and GPV was observed; no major changes were observed in surface sialylation with the exception of Mirasol-treated platelets.

CONCLUSION

In a small population of stored platelets, changes in GPIbα occur from day 2 onwards. Loss of sialic acid and subsequent shedding of GPIbα and GPV is not an early event during the development of the PSL.

Aging of platelets stored for transfusion

A goal of platelet storage is to maintain the quality of platelets from the point of donation to the point of transfusion - to suspend the aging process. This effort is judged by clinical and laboratory measures with varying degrees of success. Recent work gives encouragement that platelets can be maintained ex vivo beyond the current 5 -7 day shelf life whilst maintaining their quality, as measured by posttransfusion recovery and survival. However, additional measures are needed to validate the development of technologies that may further reduce the aging of stored platelets, or enhance their hemostatic properties.

Riboflavin and UV light treatment of platelets: a protective effect of platelet additive solution?

BACKGROUND

Pathogen reduction technologies (PRTs) increase the safety of the blood supply, but are also associated with cell damage. Our aim was to investigate the effect of Mirasol PRT on platelet (PLT) concentrates stored in plasma and whether the use of a PLT additive solution (PAS) is able to improve in vitro quality.

STUDY DESIGN AND METHODS

Twenty-two buffy coats (BCs) were pooled and split into two equal parts. To one half, 2 units of plasma were added, and to the other, 2 units of SSP+ PAS were added. Each part was equally split in half again (to resemble pooling five BCs) and PLT concentrates were prepared. One plasma PLT concentrate was Mirasol treated, and the other served as control; similarly, one SSP+ PLT concentrate was Mirasol treated, and the other not. PLT concentrates were stored for 8 days (n = 12).

RESULTS

Mirasol PRT led to elevated lactate production in PLT concentrates in plasma, giving lower pH values throughout storage. The use of SSP+ mostly abrogated this effect, and Mirasol-treated PLT concentrates in SSP+ had only slightly higher lactate production rates and annexin A5 binding as control PLT concentrates in plasma. However, irrespective whether plasma or SSP+ was used, Mirasol PRT led to higher CD62P expression and lower hypotonic shock response (HSR) scores.

CONCLUSION

Mirasol treatment leads to higher PLT activation and lower HSR scores both when stored in plasma or SSP+. However, if Mirasol-treated PLTs are stored in SSP+, lactate metabolism and annexin A5 binding are lower, showing that PAS can partly mitigate the effect of PRT. The clinical relevance of this finding needs to be demonstrated.

Extended storage of buffy coat platelet concentrates in plasma or a platelet additive solution

BACKGROUND

Platelet (PLT) concentrates (PCs) prepared from whole blood in the United States are made using the PLT-rich plasma method. The PCs must be made within 8 hours of blood collection and stored for only 5 days. In Europe and Canada, PCs are made using the buffy coat (BC) method from whole blood held overnight at 22 °C and storage times may be up to 7 days. Our studies were designed to determine how long BC PLTs can be stored in plasma or Plasmalyte while meeting the FDA's poststorage viability criteria.

STUDY DESIGN AND METHODS

Normal subjects donated whole blood that was stored at 22 °C for 22 ± 2 hours before preparation of BC PLTs. PLTs were stored for 5 to 8 days in either plasma or Plasmalyte concentrations of 65 or 80%. Radiolabeled autologous stored versus fresh PLT recoveries and survivals were assessed as well as poststorage in vitro assays.

RESULTS

BC PLTs stored in either plasma or 65% Plasmalyte met FDA poststorage PLT recovery criteria for 7 days but survivals for only 6 days, while storage in 80% Plasmalyte gave very poor results. Both stored PLT recoveries and survivals correlated with the same donor's fresh results, but the correlation was much stronger between recoveries than survivals. In vitro measures of extent of shape change, morphology score, and pH best predicted poststorage PLT recoveries, while annexin V binding best predicted PLT survivals.

CONCLUSION

BC PLTs stored in either plasma or 65% Plasmalyte meet FDA's poststorage viability criteria for 6 days.

The effects of pneumatic tube transport on fresh and stored platelets in additive solution

BACKGROUND

Limited scientific work has been conducted on potential in vitro effects of transport on pneumatic tube systems on blood components, in particular platelets.

MATERIALS AND METHODS

To evaluate the possible effects of the Swisslog TranspoNet system on the cellular, metabolic, phenotypic and secreting properties of fresh and stored platelets, we set up a four-arm paired study comparing transported and non-transported platelets. Platelets were aliquoted, prepared with the OrbiSac system and suspended in 70% SSP+ (n=8). All in vitro parameters were monitored over a 7-day storage period.

RESULTS

Throughout storage, no differences were observed in glucose consumption, lactate production, pH, pCO2, ATP, hypotonic shock response reactivity, CD62P, PAC-1, platelet endothelial cell adhesion molecule-1 or CD42b. The release of sCD40L increased (p<0.01) in all units but without any significant differences between groups.

CONCLUSION

The storage stability of all platelets conveyed by the Swisslog TranspoNet system was not impaired throughout 7 days of storage. The Swisslog TranspoNet system does not, therefore, seem to be a risk for increased metabolic activity, activation or release reactions from the platelets. This lack of effect of the pneumatic tube transport system did not seem to be affected by the age of the platelets or repeated transport.

Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS)

To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either (51)chromium or (111)indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics' bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage.

Impact of glucose and acetate on the characteristics of the platelet storage lesion in platelets suspended in additive solutions with minimal plasma

BACKGROUND AND OBJECTIVES

Glucose and acetate have been proposed to be required elements in platelet storage media. This study investigated the role of these compounds on the varied elements that comprise the platelet storage lesion.

MATERIALS AND METHODS

For each replicate, four pooled and split ABO group-specific buffy coat-derived platelet concentrates were suspended in an in-house additive solution with minimal plasma and varying final concentrations of acetate or glucose. Units were sampled on days 2, 3, 6, 8 and 10 and tested for markers of platelet morphology, activation, function, metabolism and indicators of cell death.

RESULTS

The absence of glucose was associated with a decrease in ATP, falling to a mean of 1·1 ± 0·1 μmol/10(11) plts in units with no added glucose compared with 4·2 ± 0·6 μmol/10(11) plts (P < 0·001) in units with 30 mm glucose. As glucose became depleted, the decrease in ATP to levels below 3 μmol/10(11) plts was associated with an increase in both annexin V binding and intracellular free calcium. In units lacking exogenous acetate, ATP levels on day 10 were 5·2 ± 1·5 μmol/10(11) plts compared with 2·7 ± 0·9 μmol/10(11) plts in units with 56 mm acetate (P = 0·006). Higher concentrations of exogenous acetate were associated with a lower hypotonic shock response and higher surface expression of CD62P suggestive of a dose dependency.

CONCLUSION

Under current physical storage conditions, glucose appears necessary for the maintenance of platelets stored as concentrates in minimal volumes of plasma. The addition of acetate was associated with increased platelet activation and reduced ATP levels.

Comparison of cytokine levels and metabolic parameters of stored platelet concentrates of the Fundação Hemominas, Belo Horizonte, Brazil

Background

Prolonged storage of platelets could improve availability and logistical management and decrease wastage. Immunobiochemical methods can be used to guarantee the quality of platelets after prolonged storage.

Objective

The aim of this study was to compare storage-related changes in buffy coat-derived platelet concentrations versus platelet-rich plasmal.

Methods

Units of whole blood were drawn using a quadruple-bag blood container system. Platelet-rich plasma and buffy coat prepared from whole blood following standard methods were stored for 9 days. During this period test samples were aseptically collected for analysis on Days 1, 2, 3, 5, 7 and 9.

Results

The highest CD42b expression was greater than 95%. The percentage of CD62p was significantly lower than the CD42b expression. The pH remained fairly stable during storage. Measurement of pO₂ and pCO₂ showed that oxygen levels were significantly higher than carbon dioxide levels. There were no significant differences in bicarbonate levels, glucose consumption and lactate production between the groups. The swirling effect with platelet-rich plasma samples decreased after 5 days of storage and after 7 days of storage for buffy coat samples. There was a significant twenty-fold increase in the mean IL-1β after 5 days of storage for both groups. Slight increases in IL-6 and IL-8 levels were seen at 5 days.

Conclusion

The quality of platelet concentrates remained acceptable during 7 days of storage in respect to the swirling effect, pH and platelet activation. There were no significant differences between buffy coat-derived platelets and platelet-rich plasma in this study.

Pathogen inactivation of platelets using ultraviolet C light: effect on in vitro function and recovery and survival of platelets

BACKGROUND

We evaluated the effect of treating platelets (PLTs) using ultraviolet (UV)C light without the addition of any photosensitizing chemicals on PLT function in vitro and PLT recovery and survival in an autologous radiolabeled volunteer study.

STUDY DESIGN AND METHODS

For in vitro studies, pooled or single buffy coat-derived PLT concentrates (PCs) were pooled and split to obtain identical PCs that were either treated with UVC or untreated (n = 6 each) and stored for 7 days. PLT recovery and survival were determined in a two-arm parallel autologous study in healthy volunteers performed according to BEST guidelines. UVC-treated or untreated PCs (n = 6 each) were stored for 5 days and were compared to fresh PLTs from the same donor.

RESULTS

There were no significant differences on Day 7 of storage between paired UVC-treated and control PC units for pH, adenosine triphosphate, lactate dehydrogenase, CD62P, CD63, PLT microparticles, and JC-1 binding, but annexin V binding, lactate accumulation, and expression of CD41/61 were significantly higher in treated units (p < 0.05). Compared with control units, the recovery and survival of UVC-treated PC were reduced after 5 days of storage (p < 0.05) and when expressed as a percentage of fresh values, survival was reduced by 20% (p = 0.005) and recovery by 17% (p = 0.088).

CONCLUSION

UVC-treated PLTs stored for 5 days showed marginal changes in PLT metabolism and activation in vitro and were associated with a degree of reduction in recovery and survival similar to other pathogen inactivation systems that are licensed and in use.

Optimization of platelet concentrate quality: application of proteomic technologies to donor management

Quality management of blood products is essential for blood banking. It is influenced by both processing and donor characteristics and assured by monitoring routine in vitro parameters to defined product specifications. However, these measures correlate poorly with the in vivo behavior of transfused platelets and cannot be used to select optimal donors. Since radiolabeled platelet recovery and survival studies are expensive and time consuming, there is an ongoing search for simpler measures that predict platelet transfusion outcomes. We performed a pilot study using semi-qualitative proteomics to assess changes in the platelet protein profile of donors with either acceptable or unacceptable in vivo radiolabeled autologous platelet recovery and survival measurements. Proteins changing during a 9-day storage period included cytoskeletal elements talin, vinculin and moesin as well as signal transduction proteins 14-3-3, RhoGDI and Rap1. Two of nine donations exhibited a decrease in these proteins and poor in vivo platelet recovery and survival whereas the remaining donors showed acceptable platelet recovery and survival and expected protein profiles. Analyses revealed a significant correlation between protein levels of Rap1 and RhoGDI during storage and platelet recovery and survival. This study provides for the first time preliminary data showing evidence of the utility of protein profiling to predict platelet transfusion quality. This article is part of a Special Issue entitled: Integrated omics.

Storage of platelets: effects associated with high platelet content in platelet storage containers

BACKGROUND

A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage.

MATERIALS AND METHODS

Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450-520×10(9) platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8).

RESULTS

Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration.

CONCLUSION

Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.

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

BACKGROUND

A comparative study evaluated the retention of apheresis platelet (A-PLT) in vitro properties prepared with PLT additive solution (PAS)-III or 100% plasma and stored with continuous agitation (CA) and without continuous agitation (WCA).

STUDY DESIGN AND METHODS

PLTs collected with the Amicus cell separator (Fenwal, Inc.) were utilized to prepare two matched components, each with approximately 4 × 10(11) PLTs. In the primary study, one component contained 65% PAS-III/35% plasma and the other 100% plasma. Four storage scenarios were used, one with CA and three with periods without agitation under simulated shipping conditions. In vitro assays were used early and after 5 days of storage.

RESULTS

pH levels after 5 days with CA were less with PAS-III components than 100% plasma components, with levels always above 6.6 in any component. With CA, a number of other variables were reduced even early during storage with PAS-III including morphology, extent of shape change, hypotonic stress response, adhesion, and aggregation. Storage WCA resulted in only a limited increase in the magnitude of the assay differences between PAS-III and 100% plasma components. Periods WCA did not reduce the pH below 6.6. The thromboelastograph variable associated with the strengthening of clots by PLTs was essentially comparable with PAS-III and plasma components throughout storage with CA or WCA.

CONCLUSION

The data indicate that a 100% plasma medium provides for better retention of specific in vitro PLT properties, with CA and WCA, although the clinical significance of these in vitro decrements due to PAS-III is unknown.

In vitro quality of single-donor platelets treated with riboflavin and ultraviolet light and stored in platelet storage medium for up to 8 days

BACKGROUND

The Mirasol pathogen reduction technology system is known to increase the activation and metabolic rate of platelets (PLTs). Storage of Mirasol PLTs in PLT storage medium (PSM) has the potential to slow this accelerated PLT storage lesion. We investigated the quality of Mirasol-treated PLTs stored in either 50% SSP+ or 50% Composol for 8 days.

STUDY DESIGN AND METHODS

Single-donor double hyperconcentrates were divided between control and Mirasol-treated arms and after treatment were suspended in approximately 50% (vol/vol) SSP+ (n = 8) or Composol (n = 7). In vitro markers of PLT activation and/or apoptosis were measured over an 8-day storage period.

RESULTS

Mirasol treatment resulted in increased spontaneous PLT activation and glycolysis and these effects were worsened when PLTs were treated below a certain volume (150 mL). At higher treatment volumes there were no significant differences between treated units stored in either Composol or SSP+. When low-volume units were stored in Composol the median pH fell below 6.4 on Day 5 and bicarbonate was undetectable, whereas in SSP+ the median pH value was greater than 6.9 and bicarbonate remained at detectable levels, despite other markers of in vitro function being similar to those of Composol.

CONCLUSION

Mirasol treatment of PLTs followed by storage in PSM results in increased PLT activation and metabolism to a level similar to that reported for PLTs treated and stored in plasma. Units treated at a low volume (<150 mL) showed poor in vitro quality.

Manufacture of pooled platelets in additive solution and storage in an ELX container after an overnight warm temperature hold of platelet-rich plasma

The processing of whole blood-derived platelet-rich plasma (PRP) to a platelet concentrate and platelet-poor plasma is currently performed within 8 hours to comply with the requirements to manufacture fresh frozen plasma. Maintaining PRP at room temperature for a longer period can have the advantage of shifting the completion of component manufacture onto day shifts. Pairs of ABO-identical prepooled platelets were manufactured by the PRP method, using the current approach with platelet storage in a CLX HP container (Pall Medical, Covina, CA) and plasma, or a novel approach with an 18- to a 24-hour room temperature hold of the PRP and the manufacture of pooled platelets in a glucose-containing additive solution (AS) and storage in a new ELX container (Pall Medical). Standard in vitro assays were performed on days 2, 5, and 7. The results showed that the AS platelets in ELX have in vitro characteristics that are equivalent or superior to those of the standard product.

Storage of Buffy-coat-derived platelets in additive solutions: in vitro effects on platelets prepared by the novel TACSI system and stored in plastic containers with different gas permeability

BACKGROUND

The novel TACSI system is designed for automated preparation of platelets (PLTs) from pooled buffy coats (BCs). One TACSI device will handle 6 units at the same time. The aim of our in vitro study is to investigate the effects of using this automated equipment with subsequent storage in two different plastic containers and to compare these results with PLTs prepared by the OrbiSac system.

STUDY DESIGN AND METHODS

Buffy-coat-derived PLTs (n=8) were prepared by using the TACSI system, including storage in polyvinyl chloride (PVC)-based plastic containers with di, n-decyl phthalate (DnDP) (TACSI R) and BTHC (TACSI T)-based plasticizers. As a reference, the OrbiSac System was used to prepare PLTs (n=8) with subsequent storage in a PVC plastic container with a citrate-based plasticizer (BTHC). In total, 16 TACSI and eight reference units, supplied by approximately 30% plasma and 70% SSP+, were analysed for various in vitro variables during the 7-day storage period.

RESULTS

No significant difference in PLT counts, LDH, mean platelet volume (MPV) and adenosine triphosphate between the groups was detected. Glucose was lower (P<0·05) and lactate was higher (P<0·05) in TACSI R vs. OrbiSac. With exception of day 7 (P<0·05 TACSI R vs. OrbiSac), HSR reactivity were not different between groups. Extent of shape change was lower and CD62P higher in TACSI T when compared with TACSI R and OrbiSac units (P<0·05). pH was maintained at >6·8 (day 7) and swirling remained at the highest level (score=2) for all units throughout storage.

CONCLUSION

Platelets prepared by the TACSI system with subsequent storage in two different PVC-based plastic containers were equivalent to reference PLTs with regard to in vitro characteristics during 7 days of storage.

In vitro and in vivo evaluation of apheresis platelets stored for 5 days in 65% platelet additive solution/35% plasma

BACKGROUND

In the United States, apheresis platelets (PLTs) are suspended in autologous plasma. PLT additive solutions, long used in Europe, decrease recipient allergic reactions and may reduce the risk of transfusion-related acute lung injury. We evaluated Amicus-collected PLTs stored in platelet additive solution (PAS) III (InterSol) for 5 days.

STUDY DESIGN AND METHODS

In Study 1, 71 subjects donated two products on a single day-one each stored in 100% plasma or 65% PAS III/35% plasma. Products underwent standard in vitro testing on Days 1 and 5. In Study 2, 43 additional subjects provided Amicus products stored for 5 days in 65% PAS III/35% plasma for in vivo radiolabeled recovery and survival determinations. The effect of approximately 2500cGy Day 1 gamma irradiation was evaluated in a subset of products.

RESULTS

PAS III PLTs (n=70) had a median Day 5 pH(22°C) of 7.2 (lower 95%, 95% tolerance limit, 6.9). Mean Day 5 recovery and survival of radiolabeled PAS III PLTs (n=33) were, respectively, 80.5 and 72.1%, of fresh autologous PLTs. With 95% confidence, these values were at least 66% of fresh PLT recovery and 58% of survival. All in vitro variables remained within ranges seen in licensed products for irradiated and nonirradiated PAS III PLTs.

CONCLUSION

Leukoreduced Amicus PLTs stored in 65% PAS III/35% plasma in PL-2410 containers maintained pH ≥6.9 throughout 5 days' storage. Radiolabeled PLT recovery and survival values met US Food and Drug Administration statistical criteria. Gamma-irradiated PAS III PLTs demonstrated no significant adverse effects due to irradiation in in vitro testing.

In vitro effects on platelets irradiated with short-wave ultraviolet light without any additional photoactive reagent using the THERAFLEX UV-Platelets method

BACKGROUND

A novel short-wave ultraviolet light (UVC) pathogen reduction technology (THERAFLEX UV-Platelets; MacoPharma, Mouvaux, France) without the need of any additional photoactive reagent has recently been evaluated for various bacteria and virus infectivity assays. The use of UVC alone has on the one hand been shown to reduce pathogens but may, on the other hand, have some impact on the platelet (PLT) quality. The purpose of this study was to determine the potential effects on PLT quality of pathogen inactivation treatment using the novel UVC method for PLT concentrates.

STUDY DESIGN AND METHODS

Buffy-coat-derived PLTs suspended in SSP+ were irradiated with UVC light in plastic bags (MacoPharma) made of ethyl vinyl acetate, considered to be highly permeable to UVC light. The UVC-treated (test, n=8) as well as the untreated (reference, n=8) PLT units were stored in PLT storage bags composed of n-butyryl, tri n-hexyl citrate-plasticized polyvinyl chloride (MacoPharma) on a flat bed agitator for in vitro testing during 7 days of storage.

RESULTS

No significant difference in PLT counts and lactate dehydrogenase between the groups was detected. During storage, glucose decreased more and lactate increased more in the test units. Statistically significant differences were found for glucose (P<0·01) and lactate (P<0·05) on day 7. ATP levels were higher (P<0·01 from day 5) in the reference units. With exception of day 7 (P<0·01 reference vs. test), hypotonic shock response reactivity was not different between groups. Extent of shape change was lower (P<0·01), and CD62P (P<0·05 day 5) was higher in the test units. CD42b and CD41/61 showed similar trends throughout storage, without any significant difference between the units. pH was maintained at >6·8 (day 7) and swirling remained at the highest level (score = 2) for all units throughout storage.

CONCLUSION

Our results suggest that irradiation with UVC light has a slight impact on PLT in vitro quality and appears to be insignificant with regard to current in vitro standards.

Storage of buffy-coat-derived platelets in additive solution: in vitro effects on platelets of the air bubbles and foam included in the final unit

BACKGROUND

The air bubbles and foam that develop during the preparation of platelet units have traditionally been considered to interact with the platelets, causing activation and release reactions. However, there actually seems to be no data available concerning the platelet damage that may occur as a result of air bubbles and foam present in the final unit. In this in vitro study we, therefore, investigated the effects of not removing air bubbles/foam from final platelet units, by measuring in vitro parameters during a 7-day storage period.

DESIGN AND METHODS

Platelet samples (n=8) from eight pools of 12 buffy-coats were aliquoted and prepared with the OrbiSac system for storage with (test) or without (reference) air bubbles/foam included in the final units. The metabolic, cellular and activation parameters of all units, comprising approximately 30% plasma and 70% SSP+ platelet additive solution, were analysed during the 7-day storage period.

RESULTS

Differences in platelet counts and contents between the test and reference units were detected throughout storage (p<0.05 at day 5 and p<0.01 at day 7). Lactate dehydrogenase increased during storage in the test units and was significantly higher than in the reference units (p<0.01 from day 5). The hypotonic shock response was greater in the reference units (p<0.05 on day 2 and p<0.01 from day 5). The extent of shape changes was less in the test units (p<0.05 until day 5 and p<0.01 on day 7). CD62P was higher in the test units (p<0.05 on day 7). CD42b decreased in all units but was lower in the test units (p<0.01 on day 5). CD41, CD61 and PAC-1 showed no difference throughout storage between the units (p=NS). Aggregates were visible (day 7) and occurred in three of the test units. pH was maintained at >6.8 (day 7) and swirling remained at the highest level (score =2) for all units throughout storage.

CONCLUSIONS

This study shows that storage with air bubbles/foam causes considerable enhancement of disintegration of platelets. In addition, various in vitro parameters of the platelets remaining seem to be negatively affected. The results of this study suggest that platelets should be stored without air bubbles/foam, given that these cause increased disintegration of platelets.

Extended storage of platelet-rich plasma-prepared platelet concentrates in plasma or Plasmalyte

BACKGROUND

Using bacterial detection or pathogen reduction, extended platelet (PLT) storage may be licensed if PLT viability is maintained. The Food and Drug Administration (FDA)'s poststorage PLT acceptance guidelines are that autologous stored PLT recoveries and survivals should be 66 and 58% or greater, respectively, of each donor's fresh PLT data.

STUDY DESIGN AND METHODS

Nonleukoreduced PLT concentrates were prepared from whole blood donations. Autologous PLT concentrates from 62 subjects were stored in 100% plasma (n=44) or 20% plasma/80% Plasmalyte (n=18), an acetate-based, non-glucose-containing crystalloid solution previously used for PLT storage. Fresh PLTs were obtained on the day the donor's stored PLTs were to be transfused. The fresh and stored PLTs were alternately radiolabeled with either (51) chromium or (111) indium, and in vitro measurements were performed on the stored PLTs.

RESULTS

The FDA's PLT recovery criteria were met for 7 days of plasma storage, but PLT survivals maintained viability for only 6 days. Plasmalyte-stored PLTs did not meet either acceptance criteria after 6 days of storage. After 7 days of storage, PLT recoveries averaged 43±4 and 30±4% and survivals 4.1±0.4 and 2.0±0.2 days for plasma- and Plasmalyte-stored PLTs, respectively (p=0.03 for recoveries and p<0.001 for survivals). Poststorage PLT recoveries correlated with the commonly used in vitro PLT quality measurements of hypotonic shock response and annexin V binding, while survivals correlated with extent of shape change, morphology score, and pH.

CONCLUSION

There is a progressive decrease in recoveries and survivals of plasma-stored PLTs over time. PLT viability is better maintained in plasma than Plasmalyte.

A signaling pathway contributing to platelet storage lesion development: targeting PI3-kinase-dependent Rap1 activation slows storage-induced platelet deterioration

BACKGROUND

The term platelet storage lesion (PSL) describes the structural and biochemical changes in platelets (PLTs) during storage. These are typified by alterations of morphologic features and PLT metabolism leading to reduced functionality and hence reduced viability for transfusion. While the manifestations of the storage lesion are well characterized, the biochemical pathways involved in the initiation of this process are unknown.

STUDY DESIGN AND METHODS

A complementary proteomic approach has recently been applied to analyze changes in the PLT proteome during storage. By employing stringent proteomic criteria, 12 proteins were identified as significantly and consistently changing in relative concentration over a 7-day storage period. Microscopy, Western blot analysis, flow cytometry, and PLT functionality analyses were used to unravel the involvement of a subset of these 12 proteins, which are connected through integrin signaling in one potential signaling pathway underlying storage lesion development.

RESULTS

Microscopic analysis revealed changes in localization of glycoprotein IIIa, Rap1, and talin during storage. Rap1 activation was observed to correlate with expression of the PLT activation marker CD62P. PLTs incubated for 7 days with the PI3-kinase inhibitor LY294002 showed diminished Rap1 activation as well as a moderate reduction in integrin alphaIIbbeta3 activation and release of alpha-granules. Furthermore, this inhibitor seemed to improve PLT integrity and quality during storage as several in vitro probes showed a deceleration of PLT activation.

CONCLUSION

These results provide the first evidence for a signaling pathway mediating PSL in which PI3-kinase-dependent Rap1 activation leads to integrin alphaIIbbeta3 activation and PLT degranulation.