Search

This article reviews 3 products: pathogen-inactivated platelets, cold-stored platelets, and cryoplatelets. These are all coming to a transfusion service near you in the next few years. The article reviews the limitations of these new products and highlights the gaps in our understanding of their place in patient treatment., (Copyright © 2022 by The American Society of Hematology.)

Background: There is increasing interest in leukoreduced whole blood (WB) as a transfusion product for trauma patients. In some jurisdictions, few leukoreduced filters are approved or appropriate for WB leukoreduction and quality information is therefore limited. This study assessed the impact of filtration timing of WB collected in CPDA-1 versus CPD on in vitro quality., Study Design and Methods: WB was collected in CPDA-1 or CPD and leukoreduction filtered either after 3-8 h (early) or 18-24 h (late) from stop bleed time. In vitro quality was assessed after filtration and throughout 5 weeks of storage at 4°C. Cell count and hemoglobin levels were determined by hematology analyzer, platelet activation and responsiveness to ADP by surface expression of P-selectin by flow cytometry, hemolysis by HemoCue, and metabolic parameters by blood gas analyzer. Hemostatic properties were assessed by rotational thromboelastometry. Plasma protein activities and clotting times were determined by automated coagulation., Results: Although there were some data points which showed statistically significant differences associated with anticoagulant choices or the filtration timing, no general trend in inferiority/performance could be discerned. After 35 days' storage, only clotting time, alpha angle and factor II in the early filtration arm comparing anticoagulants and prothrombin time and factor II in the CPDA-1 study arm comparing filtration timing showed a significant difference., Conclusion: In vitro WB quality seems to be independent on the choice of anticoagulant and filtration timing supporting WB hold-times to up to 24 h, increasing operational flexibility for transfusion services., (© 2022 AABB.)

Cold-stored platelets are making a comeback. They were abandoned in the late 1960s in favor of room-temperature stored platelets due to the need for longer post-transfusion platelet recoverability and survivability in patients with chronic thrombocytopenia. However, the current needs for platelet transfusions are rapidly changing. Today, more platelets are given to patients who are actively bleeding, such as ones receiving cardiac surgeries. It has been established that cold-stored platelets are more hemostatically effective, have reduced bacterial growth, and have longer potential shelf lives. These compelling characteristics led to the recent interest in bringing back cold-stored platelets to the blood systems. However, before reinstating cold-stored platelets in the clinics again, a thorough investigation of in vitro storage characteristics and in vivo transfusion effects is required. This review aims to provide an update on the recent research efforts into the storage characteristics and functions of cold-stored platelets using modern investigative tools. We will also discuss efforts made to improve cold-stored platelets to be a better and safer product. Finally, we will finish off with discussing the relevance of in vitro data to in vivo transfusion results and provide insights and directions for future investigations of cold-stored platelets.

Background: Cryopreservation of platelets (PLTs) could allow extension of their shelf-life to years, compared to days for liquid stored platelets. Due to their greater hemostatic effect, reconstituted cryopreserved platelets (cryo-PLTs) would be able to support bleeding emergencies. Since protein synthesis has been linked to PLT functions, such as clot formation and immune responses, the translational capacity of reconstituted cryo-PLTs was assessed upon thawing and short-term storage., Methods/materials: Platelets were frozen at -80°C with 5-6% DMSO. Upon thawing, they were reconstituted in plasma and then aliquoted (12 ml) into mini-bags and assessed over 24 h of storage at RT. One series served as control; the second and third series were spiked with either 300 μM puromycin (Pm) or 227 nM biotin-labeled Pm. Samples were tested for in vitro quality and PLT microvesicle enumeration by flow cytometry. Protein synthesis in cryo-PLTs was assessed using a modified method based on puromycin-associated nascent chain proteomics., Results: In vitro parameters of reconstituted and subsequently stored platelets were consistent with previously published results. Mass-spectrometry analyses identified that 22 proteins were synthesized in PLTs and 13 of those were observed in platelet microvesicles (PMVs)., Conclusion: Cryo-PLTs can synthesize proteins upon reconstitution and storage. Discovery of a subset of these proteins in the PMV suggests a role in vesicle encapsulation, possibly in a selective manner. This observation provides novel insights into the capacity for protein synthesis in cryo-PLTs and the potential regulation of protein packaging into PMV., (© 2021 AABB.)

Background: The current best practices allow for the red blood cells (RBCs) to be stored for prolonged periods in blood banks worldwide. However, due to the individual-related variability in donated blood and RBCs continual degradation within transfusion bags, the quality of stored blood varies considerably. There is currently no method for assessing the blood product quality without compromising the sterility of the unit. This study demonstrates the feasibility of monitoring storage lesion of RBCs in situ while maintaining sterility using an optical approach., Study Design and Methods: A handheld spatially offset Raman spectroscopy (RS) device was employed to non-invasively monitor hemolysis and metabolic changes in 12 red cell concentrate (RCC) units within standard sealed transfusion bags over 7 weeks of cold storage. The donated blood was analyzed in parallel by biochemical (chemical analysis, spectrophotometry, hematology analysis) and RS measurements, which were then correlated through multisource correlation analysis., Results: Raman bands of lactate (857 cm -1 ), glucose (787 cm -1 ), and hemolysis (1003 cm -1 ) were found to correlate strongly with bioanalytical data over the length of storage, with correlation values 0.98 (95% confidence interval [CI]: 0.86-1.00; p = .0001), 0.95 (95% CI: 0.71-0.99; p = .0008) and 0.97 (95% CI: 0.79-1.00; p = .0004) respectively., Discussion: This study demonstrates the potential of collecting information on the clinical quality of blood units without breaching the sterility using Raman technology. This could significantly benefit quality control of RCC units, patient safety and inventory management in blood banks and hospitals., (© 2021 AABB.)

Background: Leukoreduced whole blood (LR-WB) has received renewed attention as alternative to component-based transfusion in trauma. According to the manufacturer's instructions, leukoreduction should be carried out within 8 h after collection. This study assessed impact of (1) WB collection bag, (2) LR filtration, and (3) timing of filtration on in vitro quality., Study Design and Methods: WB collected into different vendor bags was held at room temperature for <8 h or >16 h but <24 h prior to LR. In vitro quality was assessed before and after filtration, and throughout 3 weeks of storage at 4°C. Cell count and hemoglobin levels were determined by hematology analyzer, platelet activation, and responsiveness to ADP by surface expression of P-selectin by flow cytometry, hemolysis by HemoCue, and metabolic parameters by blood gas analyzer. Hemostatic properties were assessed by rotational thromboelastometry. Plasma protein activities and clotting times were determined by automated coagulation analyzer or quantitative immunoblotting., Results: Bag type had no impact on WB in vitro quality. LR by filtration had some impact, but is aligned with data in the literature. The time between donation and filtration resulted in some statistically significant differences in metabolic activity, platelet yield, platelet activation, and factor protein activity initially; however, these differences in in vitro quality attributes decreased throughout 21-day cold storage., Conclusion: WB hold time showed only a minor impact on WB in vitro quality, so it may be possible for blood processing facilities to explore extended hold times prior to filtration in order to provide greater operational flexibility., (© 2021 AABB.)

Platelet concentrates are currently stored at room temperature (RP) under constant agitation for up to 5-7 days depending on national regulations. However, platelet quality deteriorates during storage and room-temperature storage also increases the risk of bacterial growth. Previous studies have shown that cold-stored platelets (CPs) have higher hemostatic functions and can be stored for up to 3 weeks. While these studies have compared the metabolic phenotypes of CPs and RPs, they have neither compared the impact of storage temperature and cold agitation (CPAs) on platelet function nor identified metabolic correlates to such parameters. In vitro analysis showed that CPAs and CPs had reduced count, faster CD62P expression, and increased lactadherin binding. Furthermore, CPAs and CPs had higher maximal aggregation and a reduced aggregation lag phase compared to RPs. Metabolomic analysis revealed that CPAs and CPs exhibited lower oxidative stress shown by preserved glutathione and pentose phosphate pools. CPAs and CPs also had reduced markers of beta-oxidation and amino acid catabolism, demonstrating reduced needs for energy. Agitation did not significantly impact in vitro function or metabolomic parameters of cold-stored platelets. Correlation of in vitro and metabolomic results highlighted important metabolites that may contribute to stored platelet functions. Raw data are publicly available through Metabolomics Workbench with the study identifier ST001644.

While differences among donors has long challenged meeting quality standards for the production of blood components for transfusion, only recently has the molecular basis for many of these differences become understood. This review article will examine our current understanding of the molecular differences that impact the quality of red blood cells (RBC), platelets, and plasma components. Factors affecting RBC quality include cytoskeletal elements and membrane proteins associated with the oxidative response as well as known enzyme polymorphisms and hemoglobin variants. Donor age and health status may also be important. Platelet quality is impacted by variables that are less well understood, but that include platelet storage sensitive metabolic parameters, responsiveness to agonists accumulating in storage containers and factors affecting the maintenance of pH. An increased understanding of these variables can be used to improve the quality of blood components for transfusion by using donor management algorithms based on a donors individual molecular and genetic profile.

Background: The application of riboflavin/UV-based pathogen inactivation (PI) to whole blood (WB) is currently limited by its negative impact on red blood cell (RBC) quality. The generation of reactive oxidative species in RBC products contributes to increased hemolysis. This study evaluated the impact of deoxygenation of WB prior to riboflavin/UV light treatment versus deoxygenation of RBC concentrates after PI treatment by monitoring RBC in vitro quality parameters., Study Design and Methods: Six ABO-matched WB units were pooled and split. Within three pairs, one unit was treated with riboflavin/UV light while the other was kept as an untreated control prior to manufacture into red cell concentrates (RCCs). The first pair (Cntr; Cntr-PI) served as the normoxic controls. Deoxygenation was performed at the RCC level for the second pair (RCCdeox; PI-RCCdeox), and at the WB level of the third pair (WBdeox; WBdeox-PI). In vitro qualities of the respective RBC units were assessed throughout storage., Results: The data for the Cntr and Cntr-PI units were comparable to previous reports. The PI-RCCdeox units exhibited worse in vitro quality for most parameters tested compared to Cntr-PI and WBdeox-PI units throughout storage. Hemolysis and microvesicle release was significantly (p < 0.05) higher on Days 21 and 42 in Cntr-PI units compared to WBdeox-PI units., Conclusion: WB deoxygenation may help to decrease the accelerated deterioration in RCC in vitro quality caused by treatment with riboflavin/UV light. Treatment of WB under reduced oxygen levels needs to be assessed for PI effectiveness., (© 2019 AABB.)

Background: In neonate transfusion, the use of a dedicated red blood cell (RBC) unit decreases donor exposure. A separate safety measure involves gamma irradiation of the RBCs to abrogate the possibility of transfusion-associated graft-versus-host disease. However, in combination, storage of gamma-irradiated RBCs leads to accumulation of potentially harmful substances in the supernatant., Study Design and Methods: For this study, RBCs were pooled and split into three study arms. Centrifugation or gravity was used to pack RBCs of matched units thereby reducing the amount of supernatant that would be present in neonate transfusion aliquots; these were compared to matched control units. Supernatant measurements of potassium, hemoglobin (Hb), RBC microvesicle (RMV) content, and mannitol were made in aliquots prepared weekly up to 21 days after gamma irradiation. RBC morphology and osmotic fragility were also assessed to determine if supernatant reduction methods affected the storage lesion., Results: Potassium and mannitol were significantly decreased in transfusion aliquots prepared with either of the supernatant reduction methods. On Day 21, potassium levels from supernatant-reduced aliquots were below those of Day 7 control aliquots. A decrease in free Hb was only detected on Day 21 in centrifuged aliquots. RMVs were significantly reduced in centrifuged aliquots and significantly increased in gravity-settled aliquots. The only measurable effect on storage lesion was a small increase in osmotic fragility of the RBCs subjected to supernatant reduction., Conclusion: Supernatant reduction by centrifugation effectively reduces potassium, mannitol, and RMVs in aliquots from gamma-irradiated RBCs stored up to 21 days., (© 2017 AABB.)

Background: Pathogen reduction treatment using riboflavin and ultraviolet light illumination (Mirasol) effectively reduces the risk of transfusion-transmitted infections. This treatment is currently licensed for only platelets and plasma products, while its application to whole blood (WB) to generate pathogen-inactivated red blood cells (RBCs) is under development. RBC storage lesion, constituting numerous morphologic and biochemical changes, influences RBC quality and limits shelf life. Stored RBCs further show enhanced susceptibility to RBC programmed cell death (eryptosis) characterized by increased cytosolic Ca 2+ -provoked membrane phosphatidylserine (PS) externalization., Study Design and Methods: Using a "pool-and-split" approach, we examined multiple variables of RBC storage lesion and eryptosis in RBC units, derived from Mirasol-treated or untreated WB, after 4 to 42 days of storage, under blood bank conditions., Results: In comparison to untreated RBC units, Mirasol treatment significantly altered membrane microvesiculation, supernatant hemoglobin, osmotic fragility, and intracellular adenosine triphosphate levels but did not influence membrane CD47 expression and 2,3-diphosphoglycerate levels. Mirasol-treated RBCs showed significantly higher PS exposure after 42, but not after not more than 21, days of storage, which was accompanied by enhanced cytosolic Ca 2+ activity, ceramide abundance, and oxidative stress, but not p38 kinase activation. Mirasol treatment significantly augmented PS exposure, Ca 2+ entry, and protein kinase C activation after energy depletion, a pathophysiologic cell stressor. Mirasol-treated RBCs were, however, more resistant to cell shrinkage., Conclusions: Prolonged storage of Mirasol-treated RBCs significantly increases the proportion of eryptotic RBCs, while even short-term storage enhances the susceptibility of RBCs to stress-induced eryptosis, which could reduce posttransfusion RBC recovery in patients., (© 2016 AABB.)

Individual units of donated red blood cells (RBCs) do not ordinarily undergo analytical testing prior to transfusion. This study establishes the utility of Raman spectroscopy for analyzing the biochemistry of stored RBC supernatant and reveals interesting storage-related changes about the accumulation of lactate, a chemical species that may be harmful to certain patients. The data show measurable variations in supernatant composition and demonstrate that some units of donated RBCs accumulate lactate much more readily than others. The spectra also indicate a higher relative concentration of lactate in units collected from male donors than female donors (p = 0.004) and imply that there is a greater degree of variability at later stages of storage in units from older male donors (>45 years). The study proves that Raman analysis has promise for elucidating the relationship between the metabolism of stored RBCs and donor characteristics. It also suggests that there may be benefit in developing a Raman instrument for the rapid non-invasive assessment of blood-bag biochemistry by measuring through plastic over-layers.

Background: The storage of platelets (PLTs) in additive solution (AS) may facilitate improved PLT quality and possibly extension of the PLT shelf life. A minimum amount of plasma is required when PLTs are stored in AS, as a source of glucose. The aim of this study was to assess the effect of reducing the plasma carryover to 20% on PLT quality when stored in SSP+ for an extended period., Study Design and Methods: Using a pool-and-split design, buffy coat-derived PLTs were stored in either 30% plasma/SSP+ or 20% plasma/SSP+. In vitro analyses were carried out to Day 10. Metabolites and markers of PLT activation and apoptosis were measured using a blood gas analyzer and flow cytometry. PLT apoptotic protein expression was investigated by Western blotting., Results: Glucose exhaustion occurred in the 20% plasma group between Day 7 and Day 10. The surface expression of P-selectin and PAC-1 was comparable on Day 10 in both groups, suggesting that the PLTs were not activated. However, the exposure of phosphatidylserine and the number of phosphatidylserine-positive microparticles were significantly higher in the 20% group on Day 10. The expression of the proapoptotic proteins Bak, Bax, and cleaved caspase-3 were higher in the 20% plasma group by Day 7 of storage, compared to the 30% plasma group., Conclusion: Exhaustion of glucose was associated with a proapoptotic phenotype. Results such as these should be considered before extending the PLT shelf life beyond 7 days, particularly when stored in ASs lacking glucose with low plasma carryover., (© 2015 AABB.)

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., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Whole blood (WB) can be held at room temperature (18-25°C) up to 8 hours after collection; thereafter the unit must be refrigerated, rendering it unsuitable for platelet (PLT) production. Overnight hold at room temperature before processing has logistic advantages, and we evaluated this process in an international multicenter study for both buffy coat (BC)- and PLT-rich plasma (PRP)-based blood components and compared three red blood cell (RBC) additive solutions (ASs) for their ability to offset effects of overnight hold., Study Design and Methods: Nine centers participated; seven used the BC method, and two used the PRP method. Four WB units were pooled and split; 1 unit was processed less than 8 hours from collection (Group A), and the other three (Groups B, C, and D) were held at room temperature and processed after 24 to 26 hours. RBCs in Groups A and B were resuspended in saline-adenine-glucose-mannitol, Group C in phosphate-adenine-guanosine-glucose-saline-mannitol, and Group D in ErythroSol-4 RBCs were stored at 2 to 6°C for 49 days., Results: RBCs from overnight-held WB had lower 2,3-diphosphoglycerate (2,3-DPG) and higher adenosine triphosphate (ATP). At the end of storage there were no differences between groups, apart from a slightly higher hemolysis in Group B. ErythroSol-4 showed a slightly higher initial ATP and 2,3-DPG content, but at the end of storage no differences were found., Conclusion: Overnight hold of WB before processing has no lasting deleterious effects on in vitro quality of subsequently prepared components. The use of different RBC ASs did not appear to offer significant advantages in terms of RBC quality at the end, regardless of the processing method., (© 2010 American Association of Blood Banks.)

The gradual loss of quality in stored platelets as measured collectively with various metabolic, functional, and morphologic in vitro assays is known as the platelet storage lesion. With the advent of pathogen reduction technologies and improved testing that can greatly reduce the risk for bacterial contamination, the platelet storage lesion is emerging as the main challenge to increasing the shelf life of platelet concentrates. This article discusses the contribution of platelet production methods to the storage lesion, long-established and newly developed methods used to determine platelet quality, and the significance for clinical transfusion outcome. Highlighted are the novel technologies applied to platelet storage including platelet additive solutions and pathogen inactivation., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Background: Canada converted from the platelet-rich plasma (PRP) method to the buffy coat (BC) method of processing whole blood donations between 2006 and 2008. We measured coagulation variables in plasma units during this transition, in 2006 (PRP only), 2007 (BC and PRP), and 2008 (BC only) to test the hypothesis that this conversion would not affect frozen plasma (FP) quality., Study Design and Methods: Fresh-frozen plasma (FFP; frozen within 8 hr of collection) or FP (frozen within 24 hr of collection) units were shipped on dry ice from 12 plasma manufacturing sites, thawed, and characterized using an automated coagulation analyzer, at a single testing site., Results: FP made by the BC method (FP-BC) exhibited fibrinogen, Factor (F)V, ABO-matched FVIII, and antithrombin levels at least as high as FP made by the PRP method (FP-PRP) and supported global clotting, as measured by prothrombin time or activated partial thromboplastin time, to an indistinguishable extent as FP-PRP. FP-BC and FP-PRP did not differ in ABO-matched FVIII levels, but both contained 30% to 35% less FVIII than FFP. There was no discernible effect of the site of manufacturing on plasma quality. FP-BC units leukoreduced by centrifugation contained more FV activity than those leukoreduced by filtration, but the difference was unlikely to be of clinical significance., Conclusion: Our data suggest that no reduction in FP quality, at least in the characteristics we tested, accompanied the switch from the PRP to the BC method processing of whole blood donations in Canada.

Background: With buffy coat (BC) processing of whole blood (WB) donations, the preparation of plasma occurs within 24 hours rather than 8 hours of collection. The effect of this change on coagulation factor function in plasma and cryoprecipitate was evaluated during the validation of this production method and with routine production., Study Design and Methods: Plasma frozen after an overnight hold of WB was prepared via BC or whole blood filtration (WBF) methods and quality control (QC) variables were measured. Additionally, plasma prepared with the BC method was compared to plasma produced using the platelet-rich plasma (PRP) method with an extended plasma factor analysis. Selected plasma factor levels were also measured in both cryoprecipitate and cryosupernatant plasma prepared using the WBF method from plasma frozen on the day of collection or after an overnight hold of WB., Results: When comparing BC plasma to PRP plasma, coagulation factors (F)II, VII, VIII, IX, X, and XI had somewhat lower levels, and fibrinogen and antithrombin levels were elevated. As expected the most sensitive to the prolongation of production time was FVIII with 72 and 78% of the activity of PRP plasma and cryoprecipitate, respectively. However, both still met QC standards. Similarly, products made in routine production show acceptable levels of FVIII., Conclusion: Plasma and cryoprecipitate products, prepared using methods in which the plasma is frozen close to 24 hours after collection, meet current quality standards. The longer WB storage time has been implemented into general use in Canada.

Background: Hemolysis of red blood cells (RBCs) during blood bank storage is the most obvious manifestation of RBC storage system failure. However, its analysis is made difficult because the largest source of interunit difference is donor specific. Availability of data from national blood systems on large numbers of RBC units used for internal quality control (QC) purposes and stored and processed in uniform ways permits statistical analysis., Study Design and Methods: Measures of hemolysis during and at the end of storage on randomly selected donor units observed for QC purposes were obtained from four national blood systems. Groups of these measures from units that had undergone similar processing and storage were sorted to create histograms and the histograms were compared statistically., Results: A total of 14,087 measures were obtained under seven storage conditions, including more than 12,000 measures made in a single country under four closely related conditions. Distributions of percent hemolysis are skewed normal and outliers are random. Additive solutions appear to be equivalent, except that the 42 mmol/L mannitol in AS-1 reduces hemolysis compared to conventional 30 mmol/L mannitol in saline, adenine, glucose, and mannitol. Increasing storage from 35 to 42 days increased measured hemolysis by 30% and leukoreduction decreased it by 53%., Conclusions: Large national data sets provide useful information about the distribution of hemolysis at the end of RBC storage. This information can aid blood storage system development and regulatory science.

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.

Background: Buffy coat (BC) production of platelets (PLTs) has been successfully used in Europe for more than two decades. Currently, Canadian Blood Services is implementing the BC method. This article summarizes results of the validation testing performed to qualify the process of PLT production from whole blood and compares the quality of PLTs produced in routine production by either the PLT-rich plasma method (PRP-PCs) or the BC method (BC-PCs)., Study Design and Methods: Validation data included variables used for routine quality control (QC; pH, PLT count, volume, sterility, residual white blood cell count) as well as nonroutine testing of PLTs for PLT activation, metabolic changes during storage, and PLT responsiveness to hypotonic shock and the extent of shape change induced by adenosine 5'-diphosphate. BC-PCs were tested on Days 1 and 6. QC of production runs included the same routine tests performed on Day 6., Results: PLTs produced by the BC method during validation and pilot implementation met all Canadian Standards Association standards with respect to yield, volume, pH, and leukoreduction. Additional validation testing indicated a moderate level of PLT storage lesion development. In comparison to PRP-PCs, in vitro variables of BC-PCs, either pH in this study, or other markers compared to the literature were better, suggesting that BC-PCs have less evidence of production-related damage and improved PLT quality during storage., Conclusions: PLT concentrates produced from whole blood by the BC method after an overnight hold have laboratory variables suggestive of a higher quality than those concentrates produced by the PRP method.

Platelet storage and availability for the purposes of transfusion are currently restricted by a markedly short shelf life of 5 to 7 days owing to an increased risk of bacterial growth and storage-related deterioration called the platelet storage lesion. Because most bacteria grow to confluence within 5 days during storage at room temperature, there is little increased risk of bacterial overgrowth with testing in place, and the only remaining issue is the quality of platelets during the extended storage. Although the manifestations of the storage lesion have been well studied using a variety of in vitro measures, the precise biochemical pathways involved in the initiation and progression of this process have yet to be identified. Proteomics has emerged as a powerful tool to identify and monitor changes during platelet storage and, in combination with biochemical and physiologic studies, facilitates the development of a sophisticated mechanistic view. In this review, we summarize recent experimental work that has led to a detailed overview of protein changes linked to platelet functions and signaling pathways, providing potential targets for inhibitors to ameliorate the storage lesion.

Background: Buffy-coat processing allows for the use of platelet additive solutions (PASs). PASs reduce plasma-associated transfusion reactions and conserve plasma for transfusion or fractionation. Platelet (PLT) storage in plasma was compared to storage in three commercially available PASs compared to assess their influence on in vitro laboratory variables., Study Design and Methods: Platelet concentrates (PCs) were prepared from leukoreduced pools of four buffy coats (BCPs) suspended in autologous plasma or one of PASs (Composol, Fresenius-Kabi; T-Sol, Baxter Corp.; or SSP+, MacoPharma). On Days 1, 2, 3, 5, and 7 of storage, samples were tested for PLT concentration, mean PLT volume (MPV), CD62P, morphology, pO2, pCO2, glucose, lactate and total protein concentration, pH, extent of shape change (ESC), and hypotonic shock response (HSR). Data were analyzed by analysis of variance (ANOVA) with repeated measures and t tests., Results: PLT recoveries from BCPs were higher (p < 0.05) with plasma than any PAS. Storage medium and duration did not affect PLT concentration or MPV over time. CD62P expression and morphology were significantly different among PCs pooled with different media. ANOVA showed (p < 0.05) differences among the rates of change of pCO2, pH, glucose consumption, lactate production, and ESC; PASs such as Composol and SSP+ offered excellent maintenance of pH and low rates of glucose consumption. PAS performed poorly in ESC and HSR compared to plasma. Correlation studies reveal far more significant correlations between variables of PLTs in PAS than in plasma., Conclusion: Newer PASs, for example, SSP+ and Composol, can maintain PLT integrity and moderate metabolism similarly to plasma but offer consistently lower PLT recoveries and limited osmotic balance.

Background: Suppression of the platelet (PLT) storage lesion would maintain PLT quality over longer storage times. An increased storage period would greatly improve the ability of blood agencies and hospitals to manage PLT inventories and minimize product wastage. Activation of the complement system has been proposed to play a role in initiating or potentiating the PLT storage lesion. This study examines the effect of complement inhibition on the development of the PLT storage lesion., Study Design and Methods: Leukofiltered PLT concentrates (PCs) were split into miniunits containing the complement inhibitors N-acetylaspartylglutamic acid (NAAGA) or compstatin, a control peptide, or saline. Samples were collected up to Day 11 of storage. Complement activation was monitored as C3a generation. PLT quality was assessed by morphology, CD62 and CD63 expression, fibrinogen binding, pH, mean PLT volume, annexin V binding, and PLT viability. Caspase-3 activity served as a measure of PLT apoptosis., Results: At concentrations of NAAGA required to achieve approximately 50 percent complement inhibition, PLT activation, and caspase-3 activity were increased. Complement inhibition by compstatin was highly variable. Compstatin addition consistently resulted in a 37 to 55 percent inhibition of PLT caspase-3 activity, but PLT quality and viability were no different between compstatin PCs and control PCs over the storage time., Conclusions: Neither NAAGA nor compstatin provided complete inhibition of complement over the storage period. Addition of these small-peptide inhibitors to PCs did not slow PLT storage lesion development, in spite of the partial inhibition of caspase-3 activity in the compstatin-treated PCs.

Background: Proteomics methods may be used to analyze changes occurring in stored blood products. These data sets can identify processes leading to storage-associated losses of blood component quality such as the platelet (PLT) storage lesion (PSL). The optimal strategy to perform such analyses to obtain the most informative data sets, including which proteomics methods, is undefined. This study addresses relative differences among proteomics approaches to the analysis of the PLT storage lesion., Study Design and Methods: Changes to the PLT proteome between Days 1 and 7 of storage were analyzed with three complementary proteomic approaches with final mass spectrometry analysis: two-dimensional (2D) gel electrophoresis/differential gel electrophoresis (DIGE), isotope tagging for relative and absolute quantitation (iTRAQ), and isotope-coded affinity tagging (ICAT). Observed changes in concentration during storage of selected proteins were confirmed by immunoblotting., Results: In total, 503 individual proteins changed concentration over a 7-day storage period. By method, a total of 93 proteins were identified by 2D gel/DIGE, 355 by iTRAQ, and 139 by ICAT. Less than 16 percent of the 503 proteins, however, were identified by not more than at least two proteomic approaches. Only 5 proteins were identified by all approaches. Membrane protein changes were not reliably detected with 2D gel/DIGE methods., Conclusion: Although proteomics analyses identified many storage-associated protein changes, these varied significantly by method suggesting that a combination of protein-centric (2D gel or DIGE) and peptide-centric (iTRAQ or ICAT) approaches are essential to acquire adequate data. The use of one proteomics method to study changes in stored blood products may give insufficient information.