Units Of Platelet Concentrates Research Articles

Proliferation of psychrotrophic bacteria in cold-stored platelet concentrates.

Platelet concentrates (PC) are stored at 20-24°C to maintain platelet functionality, which may promote growth of contaminant bacteria. Alternatively, cold storage of PC limits bacterial growth; however, data related to proliferation of psychotrophic species in cold-stored PC (CSP) are scarce, which is addressed in this study. Eight laboratories participated in this study with a pool/split approach. Two split PC units were spiked with ~25 colony forming units (CFU)/PC of Staphylococcus aureus, Klebsiella pneumoniae, Serratia liquefaciens, Pseudomonas fluorescens and Listeria monocytogenes. One unit was stored under agitation at 20-24°C/7 days while the second was stored at 1-6°C/no agitation for 21 days. PC were sampled periodically to determine bacterial loads. Five laboratories repeated the study with PC inoculated with lyophilized inocula (~30 CFU/mL) of S. aureus and K. pneumoniae. All species proliferated in PC stored at 20-24°C, reaching concentrations of ≤109 CFU/mL by day 7. Psychrotrophic P. fluorescens and S. liquefaciens proliferated in CSP to ~106 CFU/mL and ~105 CFU/mL on days 10 and 17 of storage, respectively, followed by L. monocytogenes, which reached ~102 CFU/mL on day 21. S. aureus and K. pneumoniae did not grow in CSP. Psychrotrophic bacteria, which are relatively rare contaminants in PC, proliferated in CSP, with P. fluorescens reaching clinically significant levels (≥105 CFU/mL) before day 14 of storage. Cold storage reduces bacterial risk of PC to levels comparable with RBC units. Safety of CSP could be further improved by implementing bacterial detection systems or pathogen reduction technologies if storage is beyond 10 days.

Impact of Shelf-Life Extension on Platelet Availability: Results from an Inventory Management Modeling Study

<b><i>Introduction:</i></b> In Germany, demand for platelet transfusion is maintained or even increasing, despite a decrease in whole blood donations observed in the last decade. The shelf-life of platelet concentrates (PCs) in Germany is 4 days, which can be extended to 5 days if appropriate safety measures are used. This short shelf-life leads to decreased PC availability. <b><i>Methods:</i></b> We investigated the impact of PC shelf-life extension on PC shortage, using a mathematical simulation model based on the PC production and delivery statistics of the Frankfurt Institute of the German Red Cross Transfusion Service of Baden-Württemberg-Hessen. We used a 2.2-year dataset for PC production and delivery as input data for a Monte Carlo inventory management simulation, focusing on PC shortage. The model generated the daily stock (expressed as mean number of PC units ± standard deviation), mean PC age at release, mean number of expired PC units, and shortage rates (i.e., requiring the release of more PCs than available), overall and by PC blood group. <b><i>Results:</i></b> Over 2.2 years, a total of 74,322 PC units were produced and 62,178 units were released at the Frankfurt Institute; the overall overproduction rate was 19.5%. Shortage rates decrease with an increase in PC shelf-life and/or increase in overproduction rates. At an overproduction rate of 20%, shortage rates would be reduced from 2.8% for a 4-day shelf-life to 0.7%, 0.3%, and 0.2%, for shelf-life lengths of 5, 6, and 7 days, respectively. Extending the PC shelf-life to 6 or 7 days would eliminate shortages almost entirely, including for rare bloods. <b><i>Conclusion:</i></b> These results can inform blood services and regulatory authorities on the potential medical and economic impact of extending PC shelf-life to 6 or 7 days.

Modulation of Staphylococcus aureus gene expression during proliferation in platelet concentrates with focus on virulence and platelet functionality.

Staphylococcus aureus is a well-documented bacterial contaminant in platelet concentrates (PCs), a blood component used to treat patients with platelet deficiencies. This bacterium can evade routine PC culture screening and cause septic transfusion reactions. Here, we investigated the gene expression modulation within the PC niche versus trypticase soy media (TSB) of S. aureus CBS2016-05, a strain isolated from a septic reaction, in comparison to PS/BAC/317/16/W, a strain identified during PC screening. RNA-seq analysis revealed upregulation of the capsule biosynthesis operon (capA-H), surface adhesion factors (sasADF), clumping factor A (clfA), protein A (spa), and anaerobic metabolism genes (pflAB, nrdDG) in CBS2016-05 when grown in PCs versus TSB, implying its enhanced pathogenicity in this milieu, in contrast to the PS/BAC/317/16/W strain. Furthermore, we investigated the impact of S. aureus CBS2016-05 on platelet functionality in spiked PCs versus non-spiked PC units. Flow cytometry analyses revealed a significant decrease in glycoprotein (GP) IIb (CD41) and GPIbα (CD42b) expression, alongside increased P-selectin (CD62P) and phosphatidylserine (annexin V) expression in spiked PCs compared to non-spiked PCs (p = 0.01). Moreover, spiked PCs exhibited a drastic reduction in MitoTrack Red FM and Calcein AM positive platelets (87.3% vs. 29.4%, p = 0.0001 and 95.4% vs. 24.7%, p = 0.0001) in a bacterial cell density manner. These results indicated that S. aureus CBS2016-05 triggers platelet activation and apoptosis, and compromises mitochondrial functionality and platelet viability, in contaminated PCs. Furthermore, this study enhanced our understanding of the effects of platelet-bacteria interactions in the unique PC niche, highlighting S. aureus increased pathogenicity and deleterious effect on platelet functionality in a strain specific manner. Our novel insights serve as a platform to improve PC transfusion safety.

Expired Platelet Concentrate Up-Cycling: Growth Factor-Rich Bioproduct Preparation for FBS Substitute

Due to the short storage period, large quantities of platelet concentrate (PC) are expiring. The expired PC cannot be injected into a blood vessel, but the activity of bioactive molecules, especially growth factors, is still preserved. In this paper, we organized a process to obtain a growth factor-rich bioproduct for use as a supplement in human cell culture by optimizing freezing, thawing, and sterilization conditions. Each unit of PC displayed visual differences, diverse biochemical values, and growth factor concentrations. To minimize lot-to-lot variation, we pooled a minimum of 10 PC units. The concentrations of growth factors were maximized through five freeze–thaw cycles for 12 h at −80 °C for freezing and for 5 min at 36 °C for thawing. We used a cell strainer with 40 µm pores, followed by a 0.45 μm filter and a 0.22 μm filter sequentially to sterilize the bioproduct with minimizing loss. The obtained growth factors remained stable for 4–6 h at room temperature (23 °C), 24 h at 4 °C, and 12 months at −80 °C. Cellular responses to the growth factor-rich bioproduct were tested with primary human renal proximal tubule epithelial cells. The cells exhibited a significantly increased growth rate, compared to the fetal bovine serum (FBS)-treated control group. The cells maintained their characteristic cuboidal shape, and stem cells and renal progenitor cells also preserved their genetic characteristics during culture. Therefore, the growth factor-rich bioproduct isolated from expired PC through our process can be used as a medium supplement to replace FBS in human cell culture for clinical application.

Evaluation of platelet additive solution for prolonging storage of functional canine platelet concentrate.

To assess storage lesion development, platelet function, and bacterial growth in canine platelet concentrates (PCs) stored in a platelet additive solution (PAS) or a plasma control at 4°C for 21days. Prospective, ex vivo, experimental controlled study. University veterinary teaching hospital. Ten units of canine PCs collected from blood bank donations. The PCs were separated into 2 bags, 1 containing 100% plasma and the other containing 35% plasma and 65% of a PAS (Plasma-Lyte A), and stored at 4°C for 21days. At days 0, 7, 14, and 21, PCs were analyzed for the presence of swirling, aggregate formation, platelet counts, platelet indices, glucose, lactate, lactate dehydrogenase, Pvco2 , Pvo2 , aggregation via light aggregometry, activation percentages using flow cytometry, and bacterial growth. Cold-stored PCs in both PAS and plasma control maintained mean pH >6.8 and mean lactate <9.0mmol/L over 21days, with no difference in glucose utilization. Swirl was maintained in both solutions for most days (76/80 combined total samples), with no difference in aggregate formation between solutions. The Pvco2 was higher in plasma on all days (P<0.001), with no difference in Pvo2 . Platelet indices did not reflect significant storage lesion development in either solution. Lactate dehydrogenase did not differ between solutions but did increase from day 7 to day 21. Mean maximal aggregation percentage was reduced overall but with no significant difference between solutions. The only observed difference in mean activation percentage between solutions was in PAS on day 7, which was significantly higher than plasma (P<0.05). No bacterial growth occurred during storage. Cold storage in PAS and plasma allowed PCs to be stored for up to 21days with minimal storage lesion development, maintenance of platelet function, limited platelet activation, and no bacterial growth within stored bags.

Quantitative increases of extracellular vesicles in prolonged cold storage of platelets increases the potential to enhance fibrin clot formation.

Platelet derived extracellular vesicles (EVs) display a pro-coagulant phenotype and are generated throughout platelet concentrate (PC) storage. Cold storage (CS) of PCs is thought to provide a superior haemostatic advantage over room temperature (RT) storage and could prolong the storage time. However, the effect of storage conditions on EV generation and PC function is unknown. We investigated EV production under CS and RT conditions and assessed whether these EVs exhibited a more pro-coagulant phenotype in model experiments. Buffy-coat-derived PCs in a platelet additive solution (PAS) to plasma ratio of approximately 65:35 were stored at RT (22 ± 2°C) or CS (4 ± 2°C) for a prolonged storage duration of 20 days. Impedance aggregometry assessed platelet function. EVs were isolated throughout storage and quantified using nanoparticle tracking analysis. EVs were applied to a coagulation assay to assess the impact on fibrin clot formation and lysis. CS produced significantly larger EVs from day 4 onwards. EV concentration was significantly increased in CS compared to RT from day 15. EVs, regardless of storage, significantly reduced time to clot formation and maximum optical density measured compared to the no EV control. Clot formation was proportionate to the number of EV applied but was not statistically different across storage conditions when corrected for EV number. EVs in CS and RT units showed similar clot formation capacity. However, the higher number of larger EVs generated in CS compared to RT suggests PC units derived from CS conditions may overall exhibit a haemostatically superior capacity compared to RT storage.

Comparison of Platelet Quality and Function Across Apheresis Collection Platforms.

Platelet concentrates (PLT) can be manufactured using a combination of apheresis collection devices and suspension media (plasma or platelet additive solution (PAS)). It is unclear how platelet quality and hemostatic function differ across the current in-use manufacturing methods in the United States. The objective of this study was therefore to compare baseline function of PLT collected using different apheresis collection platforms and storage media. PLT were collected at two sites with identical protocols(N=5 per site, N=10 total per group) on the MCS®+ 9000 (Haemonetics; "MCS"), the Trima Accel® 7 (Terumo; "Trima"), and the Amicus Cell Separator (Fresenius Kabi, "Amicus"). MCS PLT were collected into plasma while Trima and Amicus PLT were collected into plasma or PAS (Trima into Isoplate and Amicus into InterSol; yielding groups "TP", "TI" and "AP", "AI", respectively). PLT units were sampled 1 hour after collection and assayed to compare cellular counts, biochemistry, and hemostatic function. Differences in biochemistry were most evident between plasma and PAS groups, as anticipated. MCS and TP had the highest clot strength as assessed by viscoelastometry. AI had the lowest thrombin generation capacity. Both TP and TI had the highest responses on platelet aggregometry. AI had the greatest number of microparticles. Platelet quality and function differs among collection platforms at baseline. MCS and Trima platelets overall appear to trend towards higher hemostatic function. Future investigations will assess how these differences change throughout storage, and if these in vitro measures are clinically relevant. This article is protected by copyright. All rights reserved.

Sterility Testing of Platelets Concentrate Within Quality Control: Experiences and Opportunities to Extend the Application

Abstract Despite numerous measures, bacterial sepsis associated with the transfusion remains a major threat. The incidence of septic events induced by platelets transfusion is approximately 10 times higher than with transfused red blood cells due to their storage temperature. This caused new Standard that implements the methods for the detection and reduction of bacteria in the platelet concentrates (PC). The aim is to consider the possibility of wider application of this tests in order to extend the shelf-life of PC. Sterility testing of PC is done once or twice per month using BacT/Alert BPA and BacT/Alert BPN bottles. If positive, all products from the initial unit were tested to confirm or deny the status. During six years period, 67236 PC units were made and 872 of them were tested. Only two were found initially positive. After testing the other products from the same initial unit, results were negative so, final results proclaimed false positive. Pretransfusion bacterial detection is an important potential method for reducing the risk of bacteriemia and transfusion-associated septic reactions. In addition to routine measures, Mirasol PRT pathogen inactivation system, could be included. This allows certain amount of PC to be inactivated during the first 32 hours. Untreated PC units would be stored in standard conditions and for given time (three days) potentially present bacteria would reach a detectable level. This way the quantity of samples for sterility testing could be reduced, taking only 2 ml of each of four units of PC. Samples would be planted at the same vial-aerobic bottle, which would also, double the capacity in BacT/Alert 3D automated system.

Validation of blood components transport through a pneumatic tube system

IntroductionUrgent blood component transfusions may be life-saving for patients in hemorrhagic shock. Measures to reduce the time taken to provide these transfusions, such as uncrossmatched transfusion or abbreviated testing, are available. However, transport time is still an additional delay and the use of a pneumatic tube system (PTS) may be an alternative to shorten the transport time of blood components. ObjectivesTo assess pneumatic tube system transportation of blood components based on a validation protocol. Methods: Pre- and post-transport quality control laboratory parameters, visual appearance, transport time and temperature of the packed red blood cells (RBCs), thawed fresh plasma (TFP), cryoprecipitate (CR), and platelet concentrate (PC) were evaluated. Parameters were compared between transport via pneumatic tube and courier. ResultsA total of 23 units of RBCs, 50 units of TFP, 30 units of CR and ten units of PC were evaluated. No statistically significant differences were found between pre- and post-transport laboratory results. There was also no difference in laboratory parameters between transport modalities (PTS versus courier). All blood components transported matched regulatory requirements for quality criteria. The temperature during transport remained stable and the transport time via PTS was significantly shorter than the courier's transport time (p < 0.05). ConclusionThe PTS was considered a fast, safe and reliable means of transportation for blood components, also securing quality prerequisites.

Qualitative Evaluation of Platelet Concentrates Prepared with Different Methods

Introduction: One of the most important responsibility of Blood Bank is to ensure uninterrupted supply of quality blood products, namely Platelet Concentrate (PC), which are in high demand particularly during pandemic. In India, PCs are of three types prepared by different methods like Platelet Rich Plasma-Platelet Concentrate (PRP-PC), Buffy Coat Platelet Concentrates (BC- PC), and Single Donor Platelets (SDP) units. Hence, establishing optimum quality standards across all the three types of PC remains a challenge in order to maximum benefit to recipients. Aim: To assess and compare the quality parameters of platelet concentrate prepared by PRP-PC, BC-PC and apheresis methods (SDP). Materials and Methods: This laboratory based observational study was conducted at rural, tertiary care, postgraduate, teaching hospital located at South India from December 2018 to November 2019. A total of 156 PCs were studied with 52 units belonging to PRP method, 52 units BC-PC method and the remaining were 52 units of SDP prepared by apheresis method. Quality parameters include volume, pH, swirling, White Blood Cell (WBC) count/bag, platelet count/bag and platelet indices. Platelet indices include Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), and Platelet Large Cell Ratio (PLCR). Arterial Blood Gas (ABG) analysis was also done to assess (pH, partial pressure of Carbon Dioxide (pCO2), plasma bicarbonate (pHCO3-)). The p-value less than 0.05 were considered statistically significant. Statistical Package for the Social Sciences (SPSS) software version 23.0 used for statistical analysis. Results: All the 156 PC units were analysed as per the Director General of Health Services (DGHS) India, criteria. Among the 156 platelet concentrates scored as per DGHS criteria, a score of 5 was obtained for 34.61% [18/52], 30.76 [16/52] and 11.5% [6/52] SDP, BC-PC and PRP-PC units, respectively. All the PC units were sterile and Red Blood Cell (RBC) contamination was within acceptable limits. Conclusion: In this study, quality parameters of SDP was better than BC-PC and PRP-PC but with improvement and more standardisation of procedures and storage, BC-PC units can give a yield similar to that of SDP units.

Blood transfusion service in Poland in 2019

Background: In this study we evaluated the basic aspects of the activity of the Polish Blood Transfusion Service (hereinafter referred to as Centers) in 2019. Materials and methods: Retrospective analysis of the 2019-data supplied by the Centers. Results: In 2019, blood and blood components were collected in 21 Polish Centers and 129 local collection sites as well as during 13 048 mobile collections. The overall number of blood donors was estimated at 590 893, the majority of which were non-remunerated donors (590 280 — including 40 738 responders to donation appeals), as well as 57 remunerated donors and 556 autologous donors. Most frequent were whole blood collections (1 202 079) and least frequent — granulocyte concentrate collections (94) and RBCs collections by apheresis (48 donations). Whole blood was collected mostly in local collection sites (45.25%), in Centers (28.75%) and mobile collection sites (26%). Most frequently prepared blood components were RBCs — 1 180 333 units) and fresh frozen plasma (FFP — 1 344 092 units, 21.42% dedicated for clinical use). Platelet concentrates (PCs) collected by apheresis amounted to 53 379 units and 81 905 were whole blood-derived. Additional processing methods (leukocyte depletion, irradiation) were more frequently applied to PCs (43.34% leukocyte-depleted, 0.04% irradiated, 54.63% both leukocyte-depleted and irradiated) than to RBCs (18.71% leukocyte-depleted, 0.06% irradiated, 9.17% both leukocytedepleted and irradiated). Pathogen reduction technologies were applied to 20.76% of FFP units issued for clinical use (transfusion) and 11.87% of PCs. In 2019 — for a variety of reasons — 14 013 units of whole blood, 32 798 units of RBCs, 49 285 units of FFP, 1334 units of cryoprecipitate, 4778 units of pooled PCs and 1279 of apheresis PCs were wasted. Conclusions: Our study data may be considered as starting point for assessment of the tendencies observed in the Polish blood transfusion service and may serve practical-benchmarking with benefit to the transfusion community as a whole.

Computational Identification and Characterization of New microRNAs in Human Platelets Stored in a Blood Bank.

Platelet concentrate (PC) transfusions are widely used to save the lives of patients who experience acute blood loss. MicroRNAs (miRNAs) comprise a class of molecules with a biological role which is relevant to the understanding of storage lesions in blood banks. We used a new approach to identify miRNAs in normal human platelet sRNA-Seq data from the GSE61856 repository. We identified a comprehensive miRNA expression profile, where we detected 20 of these transcripts potentially expressed in PCs stored for seven days, which had their expression levels analyzed with simulations of computational biology. Our results identified a new collection of miRNAs (miR-486-5p, miR-92a-3p, miR-103a-3p, miR-151a-3p, miR-181a-5p, and miR-221-3p) that showed a sensitivity expression pattern due to biological platelet changes during storage, confirmed by additional quantitative real-time polymerase chain reaction (qPCR) validation on 100 PC units from 500 healthy donors. We also identified that these miRNAs could transfer regulatory information on platelets, such as members of the let-7 family, by regulating the YOD1 gene, which is a deubiquitinating enzyme highly expressed in platelet hyperactivity. Our results also showed that the target genes of these miRNAs play important roles in signaling pathways, cell cycle, stress response, platelet activation and cancer. In summary, the miRNAs described in this study, have a promising application in transfusion medicine as potential biomarkers to also measure the quality and viability of the PC during storage in blood banks.

Platelet safety strategies in Japan: impact of short shelf life on the incidence of septic reactions

Transfusion-transmitted bacterial infections (TTBIs) often have serious consequences for patients. The Japanese Red Cross (JRC) has not implemented culture screening for platelet concentrate (PC), but it has maintained a shelf life of 85 hours for PC. The JRC collected reports of suspected TTBI and investigated causal relationships using PC samples and patient blood samples. PCs showing apparent abnormalities were retrieved and cultured and analyzed for bacterial growth. The JRC analyzed 86 samples available from 135 transfused PCs with suspected TTBIs that were collected over the past 12 years; 17 (19.8%) were culture-positive. One, 6, and 10 TTBIs developed in patients on Days 1, 2, and 3 after PC collection, respectively. Assuming that PC is transfused on the day of issue, the TTBI risk was fourfold higher on Day 3 than on Day 2, after adjusting the TTBI incidence for the number of PCs issued per day. Compared with the model of issuing all PCs on Day 3, issuing PCs with the current distribution of storage time could have decreased the TTBI incidence by 56%. During the past 8 years, the JRC retrieved 960 PC units because of apparent abnormalities, 2.8% of which were culture-positive. The short shelf life of PC is associated with a low incidence of reported TTBIs, more than half of which occurred on Day 3 relative to earlier time points. Visual inspection of PC before transfusion is crucial in detecting bacterially contaminated PC despite its low positive predictive value.

Blood transfusion service in Poland in 2018

Background: Assessment of the basic aspects of the activity of the Polish Regional Blood Transfusion Centers (hereinafter referred to as Centers) in 2018. Materials and methods: Retrospective analysis of the 2018-data supplied by the Centers. Results: In 2018, blood and blood components were collected in 21 Centers and 132 local collection sites as well as during 13 189 mobile collections. The overall number of blood donors was estimated at 590 470; the majority were non-remunerated donors (589 897 — including 37 824 responders to donation appeals), 73 remunerated donors and 500 autologous donors. Most frequent were whole blood collections (1 184 311), least frequent — granulocyte concentrate collections (116) and red blood cell (RBC) collection by apheresis (31 donations). Whole blood was collected mostly in local collection sites (44.85%), less frequently in Centers (28.47%) and at mobile collection sites (26.67%). Most frequently prepared blood components were RBC — 1 161 600 units) and fresh frozen plasma (FFP — 1 298 216 units; 20.93% dedicated for clinical use). Platelet concentrates (PCs) collected by apheresis amounted to 50 255 units and 83 598 were whole blood-derived. Additional processing methods such as leukocyte depletion and irradiation were more frequently applied to PCs (32.56% leukocyte depleted, 1.37% irradiated, 58.07% both leukocyte depleted and irradiated) than to RBCs (17.29% leukocyte depleted, 0.31% irradiated, 8.94% both leukocyte depleted and irradiated). Pathogen reduction technologies were applied to 11.74% of PCs and 10.23% units of FFP issued for transfusion. In 2018 — for various reasons — 14 067 units of whole blood, 30 521 units of RBC, 49 979 units of FFP, 1376 units of cryoprecipitate, 5186 units of pooled PCs and 1625 of apheresis PCs were wasted. Conclusions: The study data may contribute to evaluation of the tendencies observed in Centers and may serve practical-benchmarking which in turn may prove beneficial to the transfusion community as a whole.

Metabolomics study of platelet concentrates photochemically treated with amotosalen and UVA light for pathogen inactivation

The risk of bacterial contamination and the deterioration of platelet (PLT) quality limit the shelf-life of platelet concentrates (PCs). The INTERCEPT pathogen inactivation system reduces the risk of pathogen transmission by inhibiting nucleic acid replication using a combination of a photo-reactive compound and UVA illumination. The goal of this study was to investigate the effects the INTERCEPT system has on the PLT metabolome and metabolic activity. Paired units of buffy coat-derived PCs were generated using a pool and split strategy (n = 8). The paired PCs were either treated with the INTERCEPT system or left untreated. Samples were collected on Days 1, 2, 4, and 7 of storage. Ultra-performance chromatography coupled with time-of-flight mass spectrometry was used to analyze the extra- and intracellular metabolomes. Constraint-based metabolic modeling was then used to predict the metabolic activity of the stored PLTs. A relatively large number of metabolites in the extracellular environment were depleted during the processing steps of the INTERCEPT system, in particular, metabolites with hydrophobic functional groups, including acylcarnitines and lysophosphatidylcholines. In the intracellular environment, alterations in glucose and glycerophospholipid metabolism and decreased levels of 2-hydroxyglutarate were observed following the INTERCEPT treatment. Untargeted metabolomics analysis revealed residual amotosalen dimers present in the treated PCs. Systems-level analysis of PLT metabolism indicated that the INTERCEPT system does not have a significant impact on the PLT energy metabolism and nutrient utilization. The INTERCEPT system significantly alters the metabolome of the stored PCs without significantly influencing PLT energy metabolism.

Differential Expression Profile of MicroRNAs During Prolonged Storage of Platelet Concentrates As a Quality Measurement Tool in Blood Banks.

Platelet concentrate (PC) is a key blood component, which even in good storage conditions, susceptible to cellular damage over time. Hence, blood banks discard unused PC bags after 5 days of storage. Biomarkers of PC quality are therefore highly sought after in blood bank governance. We used the data (Gene Expression Omnibus: GSE61856) generated with next-generation sequencing to examine the expression profiles of microRNAs (miRNAs) from PCs that were stored for 6 days in a blood bank, that is, 1 day longer than is normally stored PC. We identified the 14 most differentially expressed miRNAs by comparing a control PC on the first day of storage with the PCs on each of the subsequent 5 days of storage from day 1 to 6. In all, we identified nine miRNAs with the downregulated profile (miR-145-5p, miR-150-5p, miR-183-5p, miR-26a-5p, miR-331-3p, miR-338-5p, miR-451a, miR-501-3p, and miR-99b-5p) and five upregulated miRNAs (miR-1304-3p, miR-411-5p, miR-432-5p, miR-668-3p, and miR-939-5p). These miRNAs were validated by real-time quantitative PCR in 100 PC units. As each PC unit is composed of platelets of five individuals, the validation was thus performed in 500 individuals (250 men and 250 women, comprised 18-40 years old adults). The data were analyzed with hierarchical clustering and principal component analysis, which revealed the variation of mean relative expression and the instability of miRNAs half-life on the fourth day of PC storage, which coincides with time of onset of platelet storage lesions. These new observations can usefully inform future decision-making and governance in blood banks concerning PC quality.

Effect of Clopidogrel on Thrombus Formation in an Ex Vivo Parallel Plate Flow Chamber Model Cannot Be Reversed by Addition of Platelet Concentrates or vWF Concentrate.

Hemorrhage is the most important complication of antithrombotic therapy with P2Y12 receptor blockers. The administration of platelet concentrates (PCs) and von Willebrand factor (vWF) concentrates are common procedures to normalize impaired primary hemostasis in bleeding patients. We tested whether this strategy reverses the effect of clopidogrel using a parallel plate flow chamber model. Whole blood from patients, who received a loading dose of clopidogrel with 600 mg and an ongoing dual antiplatelet therapy with 75 mg/d clopidogrel and 100 mg/d acetyl salicylic acid, compared with blood from healthy volunteers was examined in a collagen-coated parallel plate flow chamber. Blood was perfused by suction at a shear rate of 300/s, which is equivalent to 14 dynes/cm to resemble shear stress in conduit arteries. Platelet-covered area, individual thrombus size, and the average thrombus size were assessed morphometrically. The equivalent of 2 or 5 units of PC and/or 2 U/mL of vWF concentrate were used in an attempt to restore coagulation capacity in blood samples of clopidogrel-treated patients. In this model, clopidogrel reduced the increase of thrombus size. The equivalent of 2 U of PC or 2 U/mL of vWF alone did not show any significant changes in thrombus size. 5 U of PC increased thrombus size in clopidogrel-treated patients (P < .05). Thrombus size in clopidogrel blood was increased by combined PC and vWF treatment (by 50%, P < .05), but this increase did not reach control levels (P < .05). This flow chamber model is suitable for detection of the antiplatelet effect of clopidogrel. Ex vivo addition of PC or vWF does not overcome the effects of clopidogrel in this model, but the combination of both shows a mild and significant improvement in thrombus size.

ASSESSMENT OF PLATELET CONCENTRATE PREPARED FROM FRESH AND OVERNIGHT HELD WHOLE BLOOD

Separation of platelet rich plasma (PRP) within 8 hours after holding whole blood at ambient temperature is the current practice in the preparation of platelet concentrate (PC). However, the ability to hold whole blood for up to 24 hours prior to PC preparation would allow every unit of whole blood to be used regardless of the distance from the collection site to the processing centre. Therefore the aim of this study is to assess and compare the platelet quality and activation of the platelet concentrate prepared from fresh whole blood (within 8 hours from collection) and overnight hold of whole blood at room temperature. In this study, 23 units of PC were prepared freshly from whole blood (i.e., within 8 hours of collection) and another 23 units were prepared after 24 hours of storage at 20–24 ºC. The following parameters of each unit of PC were assessed: pH, total white blood cell (TWBC) count, platelet count, presence of swirling, and platelet activation. When the parameters were compared between groups, no significant difference in platelet activation rate was found on sampling days 1, 3, and 5. pH and TWBC count for both groups were within the quality requirements of the National Blood Centre (&gt; 75% units tested fall within the standard), but not all of the samples complied with the standard requirement for platelet count. All units of PC prepared after 24 hours showed the presence of swirling, whereas one unit of PC in the fresh group did not show swirling activity after 3 days of storage. Delaying whole blood processing for up to 24 hours does not significantly affect certain in vitro quality or activation parameters as compared with freshly prepared PC.

Optimization of the management of platelet concentrate stocks in the Basque Country using mathematical simulation.

The management of platelet concentrate (PC) stocks is not simple given their short shelf life and variable demand. In general, managers decide on PC production based on personal experience. The objective of this study was to provide a tool to help decide how many PC units to produce each day in a more rational and objective way. From the historical data on PCs produced, transfused and discarded in the Basque Country in 2012, a mathematical model was built, based on the normality of the time series of the transfusions performed on each day of the week throughout the year. This model was implemented in an easy-to-use Excel spreadsheet and validated using real production data from 2013. Comparing with real 2013 data, in the best scenario, the number of PC units that expired was 87·7% lower, PC production, 14·3% lower and the age of the PCs transfused nearly 1-day younger in the simulation. If we want to ensure a minimum stock at the end of each day, the outdating rate and average age of the transfused PCs progressively increase. The practical application of the designed tool can facilitate decision-making about how many PC units to produce each day, resulting in very significant reductions in PC production and wastage and corresponding cost savings, together with an almost 1 day decrease in the mean age of PCs transfused.

Evaluation of Risk Minimisation Measures for Blood Components - Based on Reporting Rates of Transfusion-Transmitted Reactions (1997-2013)

Background: To assess the impact of safety measures, we compared reporting rates of transfusion-related reactions before and after the implementation of six measures in 1999, 2004, 2006, 2008 and 2009. Methods: Reporting rates of transfusion-transmitted bacterial infection (TTBI), viral infection (TTVI) and immune-mediated transfusion-related acute lung injury (TRALI) were calculated on the basis of confirmed annual reports and distributed blood components. Results: The introduction of HCV NAT testing caused a significant reduction of HCV reporting rate from 1:0.6 to 1:83.16 million administered blood components (p < 0.0001), donor screening for antibodies to hepatitis B core antigen caused a reduction of HBV reporting rate from 1:2.90 to 1:10.70 million units (p = 0.0168). A significant reduction from 1:0.094 to 1:2.42 million fresh frozen plasma (FFP) units could also be achieved by risk minimisation TRALI measures (p < 0.0001). Implementation of pre-donation sampling did not result in a significant decrease in TTBI, whereas limitation of shelf life for platelet concentrate (PC) minimised the TTBI reporting rate from 1:0.088 to 1:0.19 million PC units (p = 0.041). For HIV NAT pool testing, no significant reduction in HIV transmission was found due to very low reporting rates (1:10 million versus 1:27 million blood components, p = 0.422). Conclusion: On the basis of haemovigilance data, a significant benefit could be demonstrated for four of six implemented safety measures.