Red blood cells as oxygen carrier during normothermic machine perfusion of kidney grafts: Friend or foe?

Renal ex vivo normothermic machine perfusion (NMP) is under development as an assessment tool for high-risk kidney grafts and as a means of achieving more physiologically accurate organ preservation. On-going hemolysis has been reported during NMP, as this technique relies on red blood cells for oxygen delivery. In this study, we confirm the occurrence of progressive hemolysis during 6-hour kidney NMP. NMP-associated erythrostasis in the glomeruli and in peri-glomerular vascular networks points to an interaction between the red blood cells and the graft. Continuous hemolysis resulted in prooxidative changes in the perfusate, which could be quenched by addition of fresh frozen plasma. In a cell-based system, this hemolysis induced redox stress and exhibited toxic effects at high concentrations. These findings highlight the need for a more refined oxygen carrier in the context of renal NMP.

Donor pregnancies and transfusion recipient mortality: A role for red blood cell storage?

BACKGROUND AND OBJECTIVES

Donor characteristics have been implicated in transfusion-related adverse events. Uncertainty remains about whether sex, and specifically pregnancy history of the blood donor, could affect patient outcomes. Whether storage duration of the blood product could be important for patient outcomes has also been investigated, and a small detrimental effect of fresh products remains a possibility. Here, we hypothesize that fresh red blood cell products donated by ever-pregnant donors are associated with mortality in male patients.

MATERIALS AND METHODS

We used data from a cohort study of adult patients receiving a first transfusion between 2005 and 2015 in the Netherlands. The risk of death after receiving a transfusion from one of five exposure categories (female never-pregnant stored ≤10 days, female never-pregnant stored >10 days, female ever-pregnant stored ≤10 days, female ever-pregnant stored >10 days and male stored for ≤10 days), compared to receiving a unit donated by a male donor, which was stored for >10 days (reference), was calculated using a Cox proportional hazards model.

RESULTS

The study included 42,456 patients who contributed 88,538 person-years in total, of whom 13,948 died during the follow-up of the study (33%). Fresh units (stored for ≤10 days) from ever-pregnant donors were associated with mortality in male patients, but the association was not statistically significant (hazard ratio 1.39, 95% confidence interval 0.97-1.99). Sensitivity analyses did not corroborate this finding.

CONCLUSION

These findings do not consistently support the notion that the observed association between ever-pregnant donor units and mortality is mediated by blood product storage.

Allogeneic Serum Eye Drops: A Randomized Clinical Trial to Evaluate the Clinical Effectiveness of Two Drop Sizes

INTRODUCTION

Allogeneic serum from blood donors is starting to be used to treat patients with dry eye disease (DED). However, the optimal dose is not known. We therefore aimed to evaluate the clinical efficaciousness and user-friendliness of micro-sized versus conventional-sized allogeneic serum eye drops (SEDs).

METHODS

In a randomized trial, patients with DED first receive micro-sized SEDs (7 µl/unit) for 1 month, followed by a 1-month washout, before receiving conventional-sized SEDs (50 µl/unit) for 1 month; or vice versa. The primary endpoint was the Ocular Surface Disease Index (OSDI) score. Secondary endpoints were tear break-up time (TBT), tear production (TP), and presence of corneal punctate lesions (CP). The user-friendliness of both application systems was also compared. A linear mixed model for cross-over design was applied to compare both treatments.

RESULTS

Forty-nine patients completed the trial. The mean OSDI score significantly improved from 52 ± 3 to 41 ± 3 for micro-sized SEDs, and from 54 ± 3 to 45 ± 3 for conventional-sized SEDs. Non-inferiority (margin = 6) of micro-sized SEDs was established. We demonstrate a significant improvement for TBT in case of conventional-sized SEDs and for CP in both treatment groups. TP trended towards an improvement in both treatment groups. The user-friendliness of the conventional drop system was significantly higher.

CONCLUSIONS

For the first time, non-inferiority of micro-sized allogeneic SEDs was established. The beneficial effect of both SED volumes was similar as measured by the OSDI score. Although user-friendliness of the micro drop system was significantly lower, it is an attractive alternative as it saves valuable donor serum.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03539159).

Current transfusion practice and need for new blood products to ensure blood supply for patients with major hemorrhage in Europe

BACKGROUND

New blood products are considered for treatment of patients with major hemorrhage. The aim of this report is to describe the current transfusion practices in Europe for patients with major hemorrhage and explore the need for new or modified blood products to ensure prehospital and in-hospital blood supply.

STUDY DESIGN AND METHOD

The European Blood Alliance (EBA) Working Group on Innovation and New Blood Products' subgroup on major hemorrhage performed a survey among the EBA member states.

RESULTS

The response rate was 58% (17 responses from 15 of the 26 EBA member states). Of these, sixteen (94%) provide massive transfusion packages (MTPs) with balanced ratio of red blood cells and plasma. Seven of the respondents included platelets from the start of treatment. Eleven (65%) provide prehospital blood products, mainly red cell concentrates or dried and/or thawed plasma with 5 days of extended storage. Two countries provide prehospital whole blood. Twelve respondents (71%) saw a need for implementation of new or modified blood components in their institution. The top three priorities were whole blood (12 of 12, 100%), dried plasma (8 of 12, 67%), and cold-stored platelets (7 of 12, 58%).

DISCUSSION

Current national guidelines for use of blood products in patients with major hemorrhage in Europe agree on the use of balanced transfusion, however the timing and source of platelets differ. Blood products for prehospital transfusion are available in several European countries. An interest in new or modified blood products for patients with major hemorrhage was observed, especially for whole blood.

Mass spectrometry-based analysis on the impact of whole blood donation on the global plasma proteome

BACKGROUND

Biomonitoring may provide important insights into the impact of a whole blood donation for individual blood donors.

STUDY DESIGN AND METHODS

Here, we used unbiased mass spectrometry (MS)-based proteomics to assess longitudinal changes in the global plasma proteome, after a single blood donation for new and regular donors. Subsequently, we compared plasma proteomes of 76 male and female whole blood donors, that were grouped based on their ferritin and hemoglobin (Hb) levels.

RESULTS

The longitudinal analysis showed limited changes in the plasma proteomes of new and regular donors after a whole blood donation during a 180-day follow-up period, apart from a significant short-term decrease in fibronectin. No differences were observed in the plasma proteomes of donors with high versus low Hb and/or ferritin levels. Plasma proteins with the highest variation between and within donors included pregnancy zone protein, which was associated with sex, Alfa 1-antitrypsin which was associated with the allelic variation, and Immunoglobulin D. Coexpression analysis revealed clustering of proteins that are associated with platelet, red cell, and neutrophil signatures as well as with the complement system and immune responses, including a prominent correlating cluster of immunoglobulin M (IgM), immunoglobulin J chain (JCHAIN), and CD5 antigen-like (CD5L).

DISCUSSION

Overall, our proteomic approach shows that whole blood donation has a limited impact on the plasma proteins measured. Our findings suggest that plasma profiling can be successfully employed to consistently detect proteins and protein complexes that reflect the functionality and integrity of platelets, red blood cells, and immune cells in blood donors and thus highlights its potential use for donor health monitoring.

Recommendations for in vitro evaluation of blood components collected, prepared and stored in non-DEHP medical devices

BACKGROUND AND OBJECTIVES

DEHP, di(2-ethylhexyl) phthalate, is the most common member of the class of ortho-phthalates, which are used as plasticizers. The Medical Device Regulation has restricted the use of phthalates in medical devices. Also DEHP has been added to the Annex XIV of REACH, "Registration, Evaluation, Authorisation and Restriction of Chemicals" due to its endocrine disrupting properties to the environment. As such, the sunset date for commercialisation of DEHP-containing blood bags is May 27^th 2025. There are major concerns in meeting this deadline as these systems have not yet been fully validated and/or CE-marked. Also, since DEHP is known to affect red cell quality during storage, it is imperative to transit to non-DEHP without affecting blood product quality. Here, EBA members aim to establish common grounds on the evaluation and assessment of blood components collected, prepared and stored in non-DEHP devices.

MATERIALS AND METHODS

Based on data as well as the input of relevant stakeholders a rationale for the validation of each component was composed.

RESULTS

The red cell components will require the most extensive validation as their quality is directly affected by the absence of DEHP, as opposed to platelet and plasma components.

CONCLUSION

Studies in the scope of evaluating the quality of blood products obtained with non-DEHP devices, under the condition that they are carried out according to these recommendations, could be used by all members of the EBA to serve as scientific support in the authorization process specific to their jurisdiction or for their internal validation use.

Biotinylated Platelets: A Promising Labeling Technique?

Labeling of platelets (PLTs) is essential for research purposes, in order to measure the recovery and survival of transfused PLTs in vivo. Biotinylation is a promising new alternative to the gold standard of radioactive labeling. This review highlights 4 key publications that provide significant insights into biotin-labeled PLTs (bioPLTs). Stohlawetz et al. established that transfusion of bioPLTs in human recipients is possible. De Bruin et al. developed a standardized, reproducible protocol for biotinylation of PLTs as a promising method to trace and isolate transfused PLTs in vivo, with reduced levels of PLT activation markers. Muret et al. developed a nonwashing biotin labeling method to implement in a blood bank environment. Finally, in a preclinical study, Ravanat et al. showed that different densities of biotin can be used to concurrently monitor multiple populations of human PLTs in the circulation of the same subject. These studies have made major contributions to the development of bioPLTs as a viable option for use in human research, and indicate that bioPLTs can be safely administered, preferably at a low density of biotin.

Assessment of the soluble proteins HMGB1, CD40L and CD62P during various platelet preparation processes and the storage of platelet concentrates: The BEST collaborative study

BACKGROUND

Structural and biochemical changes in stored platelets are influenced by collection and processing methods. This international study investigates the effects of platelet (PLT) processing and storage conditions on HMGB1, sCD40L, and sCD62P protein levels in platelet concentrate supernatants (PCs).

STUDY DESIGN/METHODS

PC supernatants (n = 3748) were collected by each international centre using identical centrifugation methods (n = 9) and tested centrally using the ELISA/Luminex platform. Apheresis versus the buffy coat (BC-PC) method, plasma storage versus PAS and RT storage versus cold (4°C) were investigated. We focused on PC preparation collecting samples during early (RT: day 1-3; cold: day 1-5) and late (RT: day 4-7; cold: day 7-10) storage time points.

RESULTS

HMGB1, sCD40L, and sCD62P concentrations were similar during early storage periods, regardless of storage solution (BC-PC plasma and BC-PC PAS-E) or temperature. During storage and without PAS, sCD40L and CD62P in BC-PC supernatants increased significantly (+33% and +41%, respectively) depending on storage temperature (22 vs. 4°C). However, without PAS-E, levels decreased significantly (-31% and -20%, respectively), depending on storage temperature (22 vs. 4°C). Contrastingly, the processing method appeared to have greater impact on HMGB1 release versus storage duration. These data highlight increases in these parameters during storage and differences between preparation methods and storage temperatures.

CONCLUSIONS

The HMGB1 release mechanism/intracellular pathways appear to differ from sCD62P and sCD40L. The extent to which these differences affect patient outcomes, particularly post-transfusion platelet increment and adverse events, warrants further investigation in clinical trials with various therapeutic indications.

Aged versus fresh autologous platelet transfusion in a two-hit healthy volunteer model of transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a severe complication of blood transfusion that is thought of as a two-hit event: first the underlying patient condition (e.g., sepsis), and then the transfusion. Transfusion factors include human leukocyte antigen antibodies or biologic response modifiers (BRMs) accumulating during storage. Preclinical studies show an increased TRALI risk with longer stored platelets, clinical studies are conflicting. We aim to discover whether longer platelet concentrate (PC) storage time increases TRALI risk in a controlled human experiment.

STUDY DESIGN AND METHODS

In a randomized controlled trial, 18 healthy male volunteers received a first hit of experimental endotoxemia (2 ng/kg lipopolysaccharide), and a second hit of fresh (2-day old) or aged (7-day old) autologous PC, or physiological saline. After 6 h, changes in TRALI pathways were determined using spirometry, chest X-ray, and bronchoalveolar lavage (BAL).

RESULTS

All subjects reacted adequately to lipopolysaccharide infusion and satisfied SIRS criteria (increased pulse [>90/min] and temperature [>38°C]). There were no differences between the saline, fresh, and aged PC groups in BAL-fluid protein (95 ± 33 μg/ml; 83 ± 21 μg/ml and 104 ± 29 μg/ml, respectively) and relative neutrophil count (1.5 ± 0.5%; 1.9 ± 0.8% and 1.3 ± 0.8%, respectively), nor in inflammatory BAL-fluid BRMs (Interleukin-6, CXCL8, TNFα , and myeloperoxidase), clinical respiratory parameters, and spirometry results. All chest X-rays were normal.

CONCLUSIONS

In a human endotoxemia model of autologous platelet transfusion, with an adequate first hit and platelet storage lesion, transfusion of 7-day-old PC does not increase pulmonary inflammation compared with 2-day-old PC.

Donor variation in stored platelets: Higher metabolic rates of platelets are associated with mean platelet volume, activation and donor health

BACKGROUND

Platelets (PLTs) differ in glycolytic activity, resulting in rapid acidification of 'poor' storing PLT concentrates (PCs) in plasma, or depletion of glucose when stored in PLT additive solution (PAS). We aimed to understand why PLT glycolysis rates vary between donors and how this affects storage performance.

STUDY DESIGN AND METHODS

Buffy coats from donors <45, 45-70 and >70 years were selected and single-donor PCs in plasma or PAS-E were prepared. PCs were stored for 8 days at 22 ± 2°C and sampled regularly for analysis. Mitochondrial activity was analyzed with an Oroboros oxygraph. Age groups, or subgroups divided into quartiles based on glucose consumption, were analyzed with ANOVA.

RESULTS

In each comparison, PCs of the different groups were not different in volume and cellular composition. PLTs with the highest glucose consumption had a higher initial mean platelet volume (MPV) and developed higher CD62P expression and Annexin A5 binding during storage. Higher glycolytic activity in these PLTs was not a compensation for lower mitochondrial ATP production, because mitochondrial ATP-linked respiration of fresh PLTs correlated positively with MPV (R²  = 0.71). Donors of high glucose-consuming PLTs had more health-related issues. Storage properties of PCs from donors over 70 were not significantly different compared to PCs from donors younger than 45 years.

CONCLUSIONS

High glucose-consuming PCs developing higher activation levels, not only displayed enhanced mitochondrial activity but were also found to contain larger PLTs, as determined by MPV. Storage performance of PLTs was found to be associated with donor health, but not with donor age.

Prophylactic furosemide to prevent transfusion-associated circulatory overload: a randomized controlled study in rats

Transfusion-associated circulatory overload (TACO) is the leading cause of transfusion related morbidity and mortality. The only treatment is empirical use of furosemide. Our aim was to investigate if furosemide can prevent TACO. A randomized controlled trial was performed using a previously validated two-hit rat model for TACO. Volume incompliance was induced (first hit) in anemic, anesthetized Lewis rats. Rats were randomized to placebo, low-dose (5 mg kg-1) or high-dose (15 mg kg-1) furosemide-administered prior to transfusion (second-hit) and divided over two doses. Primary outcome was change in left-ventricular end-diastolic pressure (∆LVEDP) pre- compared to post-transfusion. Secondary outcomes included changes in preload, afterload, contractility and systemic vascular resistance, as well as pulmonary outcomes. Furosemide treated animals had a significantly lower ∆LVEDP compared to placebo (p = 0.041), a dose-response effect was observed. ∆LVEDP in placebo was median + 8.7 mmHg (IQR 5.9-11), + 3.9 (2.8-5.6) in the low-dose and 1.9 (- 0.6 to 5.6) in the high-dose group. The effect of furosemide became apparent after 15 min. While urine output was significantly higher in furosemide treated animals (p = 0.03), there were no significant changes in preload, afterload, contractility or systemic vascular resistance. Furosemide rapidly and dose-dependently decreases the rise in hydrostatic pulmonary pressure following transfusion, essential for preventing TACO.

Differential effects of speed and volume on transfusion-associated circulatory overload: A randomized study in rats

BACKGROUND AND OBJECTIVES

Transfusion-associated circulatory overload (TACO) is the primary cause of transfusion-related mortality. Speed and volume of transfusion are major risk factors. The aim of this study was to investigate the interaction of red blood cell (RBC) transfusion speed and volume on the development of TACO.

MATERIALS AND METHODS

A validated model for TACO in anaemic Lewis rats with an acute myocardial infarction was used. The effect on pulmonary hydrostatic pressure of one, two or four units of packed RBCs transfused in either 30 or 60 min was evaluated (3.3-26.6 ml·kg-1 ·hr-1 ). Pulmonary capillary pressure was measured as left ventricular end-diastolic pressure (LVEDP). Cardiac stress biomarkers atrial natriuretic-peptide (ANP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured 1-h post-transfusion.

RESULTS

Thirty animals were included (n = 5 per group). Transfusion of RBCs increased LVEDP in a volume-dependent manner (ΔLVEDP [mmHg]: -0.95, +0.50, +6.26, p < 0.001). Fast transfusion increased overall ΔLVEDP by +3.5 mmHg and up to +11.8 mmHg in the four units' group (p = 0.016). Doubling transfusion speed increased ΔLVEDP more than doubling volume in the larger volume groups. No difference in ANP or NT-proBNP were seen in high transfusion volume or groups.

CONCLUSION

Transfusion volume dose-dependently increased LVEDP, with speed of transfusion rapidly elevating LVEDP at higher transfusion volumes. ANP and NT-proBNP were not impacted by transfusion volume or speed in this model. TACO is seen as purely volume overload, however, this study emphasizes that limiting transfusion speed, as a modifiable risk factor, might aid in preventing TACO.

Evaluation of platelet concentrates prepared from whole blood donations with collection times between 12 and 15 min: The BEST Collaborative study

BACKGROUND AND OBJECTIVES

In many countries, whole blood (WB) donations with collection times between 12 and 15 min are not allowed to be used for platelet concentrates (PC). Since the development of guidelines, many process-related changes have been introduced. We aimed to determine the effect of WB with long collection times on PC quality.

MATERIALS AND METHODS

Five participating centres tested buffy coat (BC)-derived PC in platelet additive solution type E prepared from only WB collections lasting <12 min (control) versus similar PC including one BC from a collection lasting >12 min (study group, n = 8). One centre produced platelet-rich plasma (PRP)-derived PC from single donations (<10 or >12 min). All PC were stored at 22 ± 2°C and sampled on Days 1, 6 and 8 post-collection for in vitro quality determination.

RESULTS

Average collection time was significantly longer in the study group compared to controls (8.9 ± 2.6 vs. 7.3 ± 1.3 min, p < 0.001). There were no differences in volume, platelet concentration, basal CD62P expression, soluble-CD62P and CCL5 levels, or nucleotide content between the groups. Stimulation with TRAP-6 resulted in comparable levels of cell surface CD62P. On Day 8, all PC fulfilled requirements for pH. The findings from single PRP-derived PC centre were similar.

CONCLUSION

PC with one BC and single PRP derived from collections lasting >12 min had equivalent in vitro quality to controls during storage. This study provides evidence that 12-15 min donations should not be excluded for PC preparation and justifies to readdress the guidelines to <15 min instead of <12 min of collection in line with current practice in some countries.

Transfusion practice in the bleeding critically ill: An international online survey-The TRACE-2 survey

BACKGROUND

Transfusion is very common in the intensive care unit (ICU), but practice is highly variable, as has recently been shown in non-bleeding critically ill patients practices survey. Bleeding patients in ICU require different blood products across a range of specific patient categories. We hypothesize that a large variety in transfusion practice exists in bleeding patients.

STUDY DESIGN AND METHODS

An international online survey was performed among physicians working in the ICU. Transfusion practice in massively and non-massively bleeding patients was examined, including transfusion ratios, thresholds, and the presence of transfusion guidelines.

RESULTS

Six hundred eleven respondents filled in the survey of which 401 could be analyzed, representing 64 countries. Among the respondents, 52% had a massive transfusion protocol (MTP) available at their ICU. In massively bleeding patients, 46% of the respondents used fixed transfusion component ratios. Of those who used fixed blood ratios, the 1:1:1 ratio (red blood cell [RBC] concentrates: plasma: platelet concentrates) was most commonly used (33%). The presence of an MTP was associated with a more frequent use of fixed ratios (p < .001). For RBC transfusion in the general non-massively bleeding ICU population, a hemoglobin (Hb) threshold of 7.0[7.0-7.3] g/dl was reported. In the general ICU population, a platelet count threshold of 50[26-50] × 10⁹ /L was applied.

DISCUSSION

Half of the centers had no massive transfusion protocol available. Transfusion practice in massively bleeding critically ill patients is highly variable and driven by the presence of an MTP. In the general non-massively bleeding ICU population restrictive transfusion triggers were chosen.

Allogeneic and autologous serum eye drops: a pilot double-blind randomized crossover trial

Purpose

Serum eye drops (SEDs) are used to treat a variety of ocular surface defects. Serum eye drops (SEDs) are normally produced from the patient’s blood. However, not all patients can donate sufficient or suitable blood, and logistics can be challenging. Allogeneic blood from voluntary blood donors does not have these disadvantages. Our aim was to evaluate whether autologous and allogeneic SEDs have comparable efficacy and tolerability.

Methods

In a prospective, double‐blind crossover trial, patients with severe dry eyes were randomized to first receive autologous SEDs for one month, followed by one‐month washout, before receiving allogeneic SEDs for 1 month; or receive the SED preparations in reverse order. The Ocular Surface Disease Index (OSDI) was the primary endpoint, and various secondary endpoints were determined. A linear mixed model with random intercept for each patient was applied per treatment group to compare the pre‐ and postoutcome measurements.

Results

Nineteen patients were enrolled, of whom 15 completed the trial. When autologous SEDs were used, the mean ± SD OSDI improved from 62 ± 19 to 57 ± 18. For allogeneic SEDs, the OSDI changed from 59 ± 20 to 56 ± 23. The estimated mean difference (95% confidence interval) was −4.2 (−9.5 to 1.2) for autologous and −4.5 (−9.8 to 0.9) for allogeneic SEDs (both, not significant). Adverse events were mild and resolved completely.

Conclusion

Autologous and allogeneic SEDs have comparable efficacy and tolerability for use in patients with severe dry eyes. Allogeneic SEDs are therefore an attractive alternative for patients who need SEDs but are clinically or logistically unable to donate blood.

Recovery of platelet-rich red blood cells and acquisition of convalescent plasma with a novel gravity-driven blood separation device

Objectives

Our objectives were to determine the separation characteristics and blood product quality of a gravity‐driven microfiltration blood separation system (HemoClear, The Netherlands).

Background

A range of centrifugal blood separation devices, including intraoperative cell salvage devices (cell savers) and apheresis machines, are available to assist in preparing both allogenic and autologous blood products. These devices are expensive to operate and require extensive training.

Methods and Materials

Nine whole blood units were collected under standard conditions and analysed for haematological parameters, thromboelastographic properties, platelet morphology and activation, and red blood cell (RBC) deformability and morphology. Three whole blood units were separated by means of the HemoClear device, into a liquid and cellular component. The cellular component was diluted with SAGM and cold stored for 14 days. To simulate cell salvage six whole blood units were diluted with isotonic saline, followed by multiple HemoClear separation rounds.

Results

The recovery of both RBCs (100 ± 1.6%) and white blood cells (99 ± 4.5%) after undiluted filtration were very high, while platelet recovery was high (83 ± 3.0%). During the filtration, and cold storage after filtration storage both the non‐deformable RBC fraction and the RBC maximum elongation remained stable. Parameters of thromboelastography indicated that platelets remain functional after filtration and after 7 days of cold storage. In the cell salvage simulation the total protein load in the cellular fraction was reduced by 65 ± 4.1% after one washing round and 84 ± 1.9% after two consecutive washing rounds.

Conclusion

The novel blood filter studied effectively separates whole blood into diluted plasma and platelet‐rich RBCs. Moreover, the device effectively washed diluted whole blood, driving over 80% of proteins to the liquid component.

The endosomal RIN2/Rab5C machinery prevents VEGFR2 degradation to control gene expression and tip cell identity during angiogenesis

Sprouting angiogenesis is key to many pathophysiological conditions, and is strongly regulated by vascular endothelial growth factor (VEGF) signaling through VEGF receptor 2 (VEGFR2). Here we report that the early endosomal GTPase Rab5C and its activator RIN2 prevent lysosomal routing and degradation of VEGF-bound, internalized VEGFR2 in human endothelial cells. Stabilization of endosomal VEGFR2 levels by RIN2/Rab5C is crucial for VEGF signaling through the ERK and PI3-K pathways, the expression of immediate VEGF target genes, as well as specification of angiogenic 'tip' and 'stalk' cell phenotypes and cell sprouting. Using overexpression of Rab mutants, knockdown and CRISPR/Cas9-mediated gene editing, and live-cell imaging in zebrafish, we further show that endosomal stabilization of VEGFR2 levels is required for developmental angiogenesis in vivo. In contrast, the premature degradation of internalized VEGFR2 disrupts VEGF signaling, gene expression, and tip cell formation and migration. Thus, an endosomal feedforward mechanism maintains receptor signaling by preventing lysosomal degradation, which is directly linked to the induction of target genes and cell fate in collectively migrating cells during morphogenesis.

Variation in platelet-rich plasma compositions used for wound healing indications

At present, the role of platelet-rich plasma (PRP) in burn and wound management is undefined. We present some of the evidence for PRP in wound healing and other medical fields. Currently, the high variation in product composition, mode and timing of application prevent a clear definition of the position of PRP in wound healing. Perspectives on solving these issues are described.

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer

Background

Manufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two‐site appraisal of the system.

Study Design and Methods

Performance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration.

Results

Linearity studies up to 19 000 RBCs/μL demonstrated good correlation between expected and observed results (R² ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R² = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/μL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/μL) than those produced with the buffy coat method either manually (median, 681 RBCs/μL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/μL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/μL were also detected by the BB mode.

Conclusion

The BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Using fibrin sealant for skin graft fixation to avoid sedation in children with burns: a prospective study

OBJECTIVE

To investigate whether a fibrin sealant, Fitrix (Sanquin Blood Supply Foundation, The Netherlands), for fixation of skin grafts in children with burn wounds is less invasive and equally effective in comparison with skin staples.

METHOD

A single-centre prospective observational cohort study was conducted. Children requiring skin grafting after burns were included and received the fibrin sealant. This group was compared with a retrospective control group of children whose skin grafts were fixed with skin staples. Study outcomes were graft take, graft dislocation, other wound complications, healing and need for sedation.

RESULTS

In the fibrin sealant and the control groups, 17 and 27 patients were included, respectively. The percentage of total body surface area (%TBSA) grafted was smaller (p=0.028) in the fibrin sealant group (median 1.0, interquartile range (IQR) 1.5 versus 2.0, IQR 2.5). There was no significant difference in graft take or wound healing. There were two graft dislocations in the fibrin sealant group and none in the control group. Other complications included a patient with graft failure in the fibrin sealant group, and another patient with a vanishing graft and wound infection in the control group. There were fewer sedations in the fibrin sealant group compared with the control group (one versus 20, p<0.0001).

CONCLUSION

The fibrin sealant used in this study was non-inferior for the fixation of skin grafts in comparison with skin staples, and avoided sedation procedures.

Colloid osmotic pressure of contemporary and novel transfusion products

Background and Objectives

Colloid osmotic pressure (COP) is a principal determinant of intravascular fluid homeostasis and a pillar of fluid therapy and transfusion. Transfusion‐associated circulatory overload (TACO) is a leading complication of transfusion, and COP could be responsible for recruiting additional fluid. Study objective was to measure COP of blood products as well as investigate the effects of product concentration and storage lesion on COP.

Materials and Methods

Three units of each product were sampled longitudinally. COP was measured directly as well as the determinants thereof albumin and total protein. Conventional blood products, that is red blood cell (RBC), fresh‐frozen plasma (FFP) and platelet concentrates (PLTs), were compared with their concentrated counterparts: volume‐reduced RBCs, hyperconcentrated PLTs, and fully and partially reconstituted lyophilized plasma (prLP). Fresh and maximally stored products were measured to determine changes in protein and COP. We calculated potential volume load (PVL) to estimate volume recruited using albumin's water binding per product.

Results

Colloid osmotic pressure varies widely between conventional products (RBCs, 1·9; PLTs, 7·5; and FFP, 20·1 mmHg); however, all are hypooncotic compared with human plasma COP (25·4 mmHg). Storage lesion did not increase COP. Concentrating RBCs and PLTs did not increase COP; only prLP showed a supraphysiological COP of 47·3 mm Hg. The PVL of concentrated products was lower than conventional products.

Conclusion

Colloid osmotic pressure of conventional products was low. Therefore, third‐space fluid recruitment is an unlikely mechanism in TACO. Concentrated products had a lower calculated fluid load and may prevent TACO. Finally, storage did not significantly increase oncotic pressure of blood products.

Trends in platelet distributions from 2008 to 2017: a survey of twelve national and regional blood collectors

BACKGROUND

This multi-national study evaluated changes in platelet (PLT) unit distributions at 12 national or regional blood collectors over a 10-year period.

METHODS

Data on the total number of PLT distributions, the collection method, that is apheresis vs whole blood-derived (WBD), the PLT unit characteristics and post-collection modifications were obtained from 12 national or regional blood collectors from 2008 through 2017. Individual WBD PLT units were converted to apheresis equivalent units (i.e. a dose of PLTs) by dividing by 4, the typical pool size; WBD units that were pooled before distribution were counted as a single dose.

RESULTS

Overall at these 12 blood collectors, the total number of PLTs distributed in 2008 was 1 373 200, which rose by 10·2% to 1 513 803 in 2017. The Japanese Red Cross, which distributes only apheresis PLTs, had a 13·4% increase in the number of distributions between the years 2008 and 2017, while the other 11 blood collectors combined demonstrated a 6·8% increase in distributions between these two years. Between the years 2008 and 2017, the changes in the proportion of apheresis, platelet-rich plasma and buffy coat PLT distributions were -29·9%, -70·7% and 80·0%, respectively.

CONCLUSION

The number of PLT distributions increased during the 10-year study period despite prophylactic PLT transfusion thresholds having remained fairly consistent over the last decade. Perhaps this increase is in part driven by increased administration of platelets to patients with massive haemorrhage or an increase in stem cell transplantation. The use of buffy coat PLTs is increasing at these collectors.

Volume incompliance and transfusion are essential for transfusion-associated circulatory overload: a novel animal model

BACKGROUND

Transfusion‐associated circulatory overload (TACO) is the predominant complication of transfusion resulting in death. The pathophysiology is poorly understood, but inability to manage volume is associated with TACO, and observational data suggest it is different from simple cardiac overload due to fluids. We developed a two‐hit TACO animal model to assess the role of volume incompliance (“first‐hit”) and studied whether volume overload (“second‐hit”) by red blood cell (RBC) transfusion is different compared to fluids (Ringer's lactate [RL]).

MATERIALS AND METHODS

Male adult Lewis rats were stratified into a control group (no intervention) or a first hit: either myocardial infarction (MI) or acute kidney injury (AKI). Animals were randomized to a second hit of either RBC transfusion or an equal volume of RL. A clinically relevant difference was defined as an increase in left ventricular end‐diastolic pressure (ΔLVEDP) of +4.0 mm Hg between the RBC and RL groups.

RESULTS

In control animals (without first hit) LVEDP was not different between infusion groups (Δ + 1.6 mm Hg). LVEDP increased significantly more after RBCs compared to RL in animals with MI (Δ7.4 mm Hg) and AKI (Δ + 5.4 mm Hg), respectively. Volume‐incompliant rats matched clinical TACO criteria in 92% of transfused versus 25% of RL‐infused animals, with a greater increase in heart rate and significantly higher blood pressure.

CONCLUSION

To our knowledge, this is the first animal model for TACO, showing that a combination of volume incompliance and transfusion is essential for development of circulatory overload. This model allows for further testing of mechanistic factors as well as therapeutic approaches.

Not all red cell concentrate units are equivalent: international survey of processing and in vitro quality data

INTRODUCTION

In vitro qualitative differences exist in red cell concentrates (RCCs) units processed from whole blood (WB) depending on the method of processing. Minimal literature exists on differences in processing and variability in quality data. Therefore, we collected information from blood manufacturers worldwide regarding (1) details of WB collection and processing used to produce RCCs and (2) quality parameters and testing as part of routine quality programmes.

METHODS

A secure web-based survey was developed, refined after pilot data collection and distributed to blood centres. Descriptive analyses were performed.

RESULTS

Data from ten blood centres in nine countries were collected. Six blood centres (60%) processed RCCs using the top-and-top (TAT) method which produces RCCs and plasma, and eight centres (80%) used the bottom-and-top (BAT) which additionally produces buffy coat platelets. Five of the centres used both processing methods; however, four favoured BAT processing. One centre utilized the Reveos automated system exclusively. All centres performed pre-storage leucoreduction. Other parameters demonstrated variability, including active cooling at collection, length of hold before processing, donor haemoglobin limits, acceptable collection weights, collection sets, time to leucoreduction, centrifugation speeds, extraction devices and maximum RCC shelf life. Quality marker testing also differed amongst blood centres. Trends towards higher RCC unit volume, haemolysis and residual leucoctyes were seen in the TAT compared with BAT processing across centres.

CONCLUSION

Methods and parameters of WB processing and quality testing of RCCs differ amongst surveyed blood manufacturers. Further studies are needed to assess variations and to potentially improve methods and product quality.

The effect of red blood cell transfusion on platelet function in critically ill patients

INTRODUCTION

Red blood cell (RBC) transfusion is associated with an increased risk of pro-thrombotic events, but the underlying mechanism is poorly understood. We hypothesized that RBC transfusion modulates platelet activity in critically ill patients with and without sepsis.

METHODS

In a prospective cohort study, 37 critically ill patients receiving a single RBC unit to correct for anemia were sampled prior to and 1 h after transfusion. Platelet exposure of P-selectin, CD63 and binding of PAC-1 as well as formation of platelet-leukocyte complexes were measured by flow cytometry. The ability of plasma from critically ill patients to induce ex vivo platelet aggregation was assessed by flow cytometry after incubation with platelets from a healthy donor.

RESULTS

RBC transfusion neither triggered the expression of platelet activation markers nor the formation of platelet-leukocyte complexes. Plasma from critically ill patients induced more spontaneous platelet aggregation prior to RBC transfusion compared to healthy controls, which was further augmented following RBC transfusion. Also collagen-induced platelet aggregation was already increased prior to RBC transfusion compared to healthy controls, and this response was unaffected by RBC transfusion. In contrast, ristocetin-induced platelet agglutination was decreased when compared to controls, suggesting impaired vWF-dependent platelet agglutination, even in the presence of high vWF levels. Following RBC transfusion, ristocetin-induced platelet agglutination further decreased. There were no differences between septic and non-septic recipients in all assays.

CONCLUSION

Ex vivo platelet aggregation is disturbed in the critically ill. Transfusion of a RBC unit may further increase the spontaneous platelet aggregatory response.

Biotinylation of platelets for transfusion purposes a novel method to label platelets in a closed system

BACKGROUND

Labeling of platelets (PLTs) is required to measure the recovery and survival of transfused PLTs in vivo. Currently a radioactive method is used to label PLTs. However, application of those radiolabeling methods is limited by both safety issues and the inability to isolate transfused PLTs from the circulation. Biotin‐labeled PLTs are an attractive nonradioactive option. However, no validated protocol to biotinylate PLTs is currently available for human studies.

STUDY DESIGN AND METHODS

Six PLT concentrates (PCs) were subaliquoted and biotinylated on Days 1 and 7 of storage. To distinguish the effect of the processing steps from the effects of biotin incubation, two control groups were used: 1) “sham” samples were processed without the biotinylation reagent and 2) control samples were assessed without any processing other than the PC isolation. For the biotinylation procedure, 50 mL of PCs was washed twice and incubated with 5 mg/L biotin for 30 minutes in a closed system. As measures of PLT activation, phosphatidylserine exposure and CD62p expression were assessed.

RESULTS

After biotinylation, 98.4% ± 0.9% of PLTs were labeled. PLT counts, pH, and “swirling” were within the range accepted by the Dutch blood bank for standard PLT products. Biotinylated PLTs were more activated compared than controles but not more than sham samples, but were more activated than the controls.

CONCLUSION

We developed a standardized and reproducible protocol according to Good Practice Guidelines standards, for biotin labeling of PLTs for clinical purposes. This method can be applied as nonradioactive alternative assess survival and recovery of transfused PLTs in vivo.

Apheresis causes complement deposition on red blood cells (RBCs) and RBC antigen alterations, possibly inducing enhanced clearance

BACKGROUND

Apheresis is increasingly being applied to collect cells or plasma, even allowing the collection of multiple blood components during one procedure. Although the quality of the cellular and plasma products that are obtained by apheresis have been extensively studied and shown to be of high quality, the impact of apheresis on the red blood cells (RBCs) that are returned to the donor has not been investigated.

STUDY DESIGN AND METHODS

The effect of the plasma- or plateletpheresis procedures by four different devices-MCS+ (Haemonetics), PCS2 (Haemonetics), Trima Accel (Terumo BCT), and Autopheresis-C (Auto-C, Fresenius Kabi)-on the RBCs that are returned to the donor was tested in a blinded, prospective trial in a cohort of 25 donors.

RESULTS

A rheologic analysis of donor RBCs before and after plasma- or plateletpheresis showed no differences in outcome. However, a strong increase in hemolysis was found in samples from the Trima Accel devices after plateletpheresis, compared to all other machines tested. Furthermore, an increase in complement deposition on RBCs was seen after all plasmapheresis procedures (MCS+, PCS2, and Auto-C). Finally, a significant decrease in the expression of the complement-regulating protein CD59 was seen in all postapheresis samples as well as a significant decrease of the adhesion molecule CD147.

CONCLUSION

The increase in complement deposition and the decrease in the expression of CD59 suggests that RBC clearance might be enhanced after return to the donor. Possible side effects due to an increase in hemolysis after Trima Accel plateletpheresis should be further investigated.

Loss of Thrombin-Induced Ca2+ Mobilization in a Subpopulation of Platelets during Storage

Thrombin-induced changes in cytosolic free Ca2+ ([Ca2+]i) were studied in human platelets that had been stored for up to 6 days. Changes in [Ca2+]i were measured with Indo-1-loaded platelets and quantitated with two different methods: (i) measurement of the changes in total fluorescence; (ii) measurement of the [Ca2+]i changes in individual platelets in a flow cytometer, allowing the detection of non-responding platelets. The maximal concentration of [Ca2+]i after stimulation with 0.5 U of thrombin/ml decreased from 544 ± 58 nM (mean ± SEM, n = 6) on day 0, to 276 ± 9 nM on day 3 and to 203 ± 23 nM on day 6. The percentage of platelets responding to 0.5 U of thrombin/ml declined from 90 ± 2% on day 0 to 72 ± 4% on day 3, and to 47 ± 8% on day 6. Nevertheless, also the responding platelets showed a decreased rise in [Ca2+]i.

The study shows that during platelet storage a decrease in the rise in [Ca2+]i upon thrombin stimulation occurs. This decrease is partly due to the formation of a subpopulation of platelets that is completely unresponsive and partly due to a decreased responsiveness in the remainder of the platelets; it is not due to a gradual decline in [Ca2+]i rise in all platelets. This phenomenon provides new insight in the functional defect of stored platelets.

Stored Platelets Release Nucleotides as Inhibitors of Platelet Function

It is well known that the function of platelets decreases progressively during storage of platelet concentrates at room temperature. To investigate this phenomenon in more detail, we have resuspended platelets that had been stored for 24 h or 72 h in fresh plasma, and we have measured the aggregation response and the ATP secretion. Conversely, the effect of plasma in which platelet concentrates (PC) had been stored for 24 h or 72 h, was tested on fresh platelets. Both the aggregation response to collagen and ADP and the collagen-induced ATP secretion of stored platelets partially recovered after incubation with fresh plasma (p <0.05). The same parameters measured with fresh platelets incubated in stored PC-plasma were found to be significantly reduced in comparison with the response of fresh platelets in fresh plasma (p <0.05). Finally, platelets were stored in a plasma-free medium, suitable for platelet storage and the supernatant was tested. This supernatant inhibited the function of fresh platelets in a storage time-dependent fashion. Boiling of these supernatants did not change the inhibiting capacities, whereas filtration over active charcoal did. Analysis of this supernatant revealed AMP and diadenosine tetraphosphate, which both inhibit platelet function.

These data show that stored platelets release nucleotides that inhibit platelet function in a reversible manner. This phenomenon may contribute to the decrease of platelet function during storage and the recovery of platelet function after transfusion.

Development, validation, and potential applications of biotinylated red blood cells for posttransfusion kinetics and other physiological studies: evidenced-based analysis and recommendations

The current reference method in the United States for measuring in vivo population red blood cell (RBC) kinetics utilizes chromium-51 (⁵¹ Cr) RBC labeling for determining RBC volume, 24-hour posttransfusion RBC recovery, and long-term RBC survival. Here we provide evidence supporting adoption of a method for kinetics that uses the biotin-labeled RBCs (BioRBCs) as a superior, versatile method for both regulatory and investigational purposes. RBC kinetic analysis using BioRBCs has important methodologic, analytical, and safety advantages over ⁵¹ Cr-labeled RBCs. We critically review recent advances in labeling human RBCs at multiple and progressively lower biotin label densities for concurrent, accurate, and sensitive determination of both autologous and allogeneic RBC population kinetics. BioRBC methods valid for RBC kinetic studies, including successful variations used by the authors, are presented along with pharmacokinetic modeling approaches for the accurate determination of RBC pharmacokinetic variables in health and disease. The advantages and limitations of the BioRBC method-including its capability of determining multiple BioRBC densities simultaneously in the same individual throughout the entire RBC life span-are presented and compared with the ⁵¹ Cr method. Finally, potential applications and limitations of kinetic BioRBC determinations are discussed.

Metabolic effect of alkaline additives and guanosine/gluconate in storage solutions for red blood cells

BACKGROUND

Over a century of advancements in the field of additive solutions for red blood cell (RBC) storage has made transfusion therapy a safe and effective practice for millions of recipients worldwide. Still, storage in the blood bank results in the progressive accumulation of metabolic alterations, a phenomenon that is mitigated by storage in novel storage additives, such as alkaline additive solutions. While novel alkaline additive formulations have been proposed, no metabolomics characterization has been performed to date.

STUDY DESIGN AND METHODS

We performed UHPLC-MS metabolomics analyses of red blood cells stored in SAGM (standard additive in Europe), (PAGGSM), or alkaline additives SOLX, E-SOL 5 and PAG3M for either 1, 21, 35 (end of shelf-life in the Netherlands), or 56 days.

RESULTS

Alkaline additives (especially PAG3M) better preserved 2,3-diphosphoglycerate and adenosine triphosphate (ATP). Deaminated purines such as hypoxanthine were predictive of hemolysis and morphological alterations. Guanosine supplementation in PAGGSM and PAG3M fueled ATP generation by feeding into the nonoxidative pentose phosphate pathway via phosphoribolysis. Decreased urate to hypoxanthine ratios were observed in alkaline additives, suggestive of decreased generation of urate and hydrogen peroxide. Despite the many benefits observed in purine and redox metabolism, alkaline additives did not prevent accumulation of free fatty acids and oxidized byproducts, opening a window for future alkaline formulations including (lipophilic) antioxidants.

CONCLUSION

Alkalinization via different strategies (replacement of chloride anions with either high bicarbonate, high citrate/phosphate, or membrane impermeant gluconate) results in different metabolic outcomes, which are superior to current canonical additives in all cases.

Transfusion of autologous extracellular vesicles from stored red blood cells does not affect coagulation in a model of human endotoxemia

BACKGROUND

Red blood cell (RBC) transfusion has been related to thromboembolic events. Microvesicles in the RBC product may support coagulation because they have procoagulant effects in vitro. We investigated whether transfusion of RBCs containing extracellular vesicles promotes coagulation in human recipients. As transfusion is mostly administered to ill patients, we used a model of endotoxemia.

STUDY DESIGN AND METHODS

Eighteen healthy volunteers were randomized to receive either saline or fresh (2 days stored) or stored autologous (35 days stored) RBC transfusion (Dutch Trial Register: NTR4455). Two hours after infusion of lipopolysaccharide (LPS, from Escherichia coli, 2 ng/kg body weight), subjects received either saline or fresh or stored RBCs. Blood was sampled every 2 hours up to 8 hours after LPS infusion. Vesicles were measured with a flow cytometer (A50-Micro, Apogee Flow Systems).

RESULTS

LPS resulted in increased thrombin generation compared to baseline. During storage, the total number of extracellular vesicles increased from 1.4 × 10⁸ /mL (interquartile range [IQR], 8.3 × 10⁷ -1.9 × 10⁸ /mL) in the fresh product to 1.7 × 10¹⁰ /mL (IQR, 7.9 × 10⁹ -2.3 × 10¹⁰ /mL; p < 0.01) in the stored product (p < 0.001). Vesicles appeared to be mostly RBC derived.

CONCLUSION

After transfusion, extracellular vesicles from stored RBC products, but not from fresh products, could be detected in the circulation of healthy volunteers. However, infusion of stored RBC extracellular vesicles did not augment thrombin generation compared to endotoxemic controls. Also, levels of d-dimer and thrombin-antithrombin complex were unaffected. In conclusion, transfusion of autologous RBCs containing high levels of extracellular vesicles does not enhance coagulation in human volunteers with endotoxemia.

A comprehensive proteomics study on platelet concentrates: Platelet proteome, storage time and Mirasol pathogen reduction technology

Platelet concentrates (PCs) represent a blood transfusion product with a major concern for safety as their storage temperature (20-24°C) allows bacterial growth, and their maximum storage time period (less than a week) precludes complete microbiological testing. Pathogen inactivation technologies (PITs) provide an additional layer of safety to the blood transfusion products from known and unknown pathogens such as bacteria, viruses, and parasites. In this context, PITs, such as Mirasol Pathogen Reduction Technology (PRT), have been developed and are implemented in many countries. However, several studies have shown in vitro that Mirasol PRT induces a certain level of platelet shape change, hyperactivation, basal degranulation, and increased oxidative damage during storage. It has been suggested that Mirasol PRT might accelerate what has been described as the platelet storage lesion (PSL), but supportive molecular signatures have not been obtained. We aimed at dissecting the influence of both variables, that is, Mirasol PRT and storage time, at the proteome level. We present comprehensive proteomics data analysis of Control PCs and PCs treated with Mirasol PRT at storage days 1, 2, 6, and 8. Our workflow was set to perform proteomics analysis using a gel-free and label-free quantification (LFQ) approach. Semi-quantification was based on LFQ signal intensities of identified proteins using MaxQuant/Perseus software platform. Data are available via ProteomeXchange with identifier PXD008119. We identified marginal differences between Mirasol PRT and Control PCs during storage. However, those significant changes at the proteome level were specifically related to the functional aspects previously described to affect platelets upon Mirasol PRT. In addition, the effect of Mirasol PRT on the platelet proteome appeared not to be exclusively due to an accelerated or enhanced PSL. In summary, semi-quantitative proteomics allows to discern between proteome changes due to Mirasol PRT or PSL, and proves to be a methodology suitable to phenotype platelets in an unbiased manner, in various physiological contexts.

Platelet Additive Solutions: A Review of the Latest Developments and Their Clinical Implications

Summary Platelet additive solutions (PASs) have undergone many reformulations in order to further improve platelet storage. Studies of platelets stored in PAS-F (containing acetate, magnesium and potassium as key constituents) showed that platelets may be stored for 13 days with recovery and survival outcomes that are equal or even superior to 7-day stored platelets in plasma. Clinically, patients transfused with platelets in PAS have fewer allergic reactions, while for febrile reactions data are conflicting. Transfusion-related acute lung injury (TRALI) occurs less frequently if PAS is used for buffy coat-derived platelets, but for apheresis platelets there is no difference. For PAS-B and PAS-C, corrected count increments (CCIs) are lower than for platelets stored in plasma, but for PAS-E (like PAS-F also with acetate, magnesium and potassium but with additional phosphate), though limited data is available in the literature, the CCIs seem to be comparable to those observed for platelets in plasma. With platelets in PAS, there is an accumulated dilution effect of anticoagulant and PAS as well as a loss of number and function (due to storage and/or pathogen inactivation treatment) of platelets, of which it is not clear how this impacts clinical outcomes of patients undergoing massive transfusion. Worst-case in vitro studies, where the entire plasma fraction is replaced by supernatant of platelets in PAS, do show an effect on the ability of reconstituted whole blood to clot, but in a more realistic scenario, functional clotting parameters are not different. In this review, recent laboratory and clinical data are discussed, focusing on studies published after 2010.

A method for red blood cell biotinylation in a closed system

BACKGROUND

Several circumstances require the accurate measurement of red blood cell (RBC) survival and clearance, such as determination of posttransfusion recovery of stored RBCs to investigate the effect of new additive solutions. To this end, biotin as a marker of RBCs to track donor RBCs in the blood of the recipient has been used in many studies. However, so far only experimental, nonvalidated, biotin-labeled red cell concentrates (RCCs) are transfused. The goal of this study was to produce a standardized biotin-labeled RCC product in a fast, simple, and sterile manner that can be used for clinical research and for the evaluation of new blood products according to Good Practice Guidelines (GPG) for blood establishments.

STUDY DESIGN AND METHODS

RCC fractions were labeled with two different concentrations of biotinylation reagent in a closed system, to prevent bacterial contamination of the end product. Using flow cytometry, the reproducibility and robustness of the biotin labeling was assessed, as well as the stability of the biotin label on the (un-)irradiated RCC fraction. Additionally, parameters such as phosphatidylserine (PS) exposure, sodium (Na), potassium (K), free hemoglobin, adenosine triphosphate (ATP), pH, and morphology were determined prior to and after biotin labeling to rule out detrimental effects of the labeling procedure on the RCC.

RESULTS

Our data show that RCCs can be labeled under sterile conditions in a closed system with two different biotinylation reagent concentrations, without affecting the biological activity.

CONCLUSION

An easy, rapid (<2 hr), and robust method was developed to manufacture biotin-labeled RCCs for clinical research compliant to GPG.

Comparison of Spectrophotometry, Chromate Inhibition, and Cytofluorometry Versus Gene Sequencing for Detection of Heterozygously Glucose-6-Phosphate Dehydrogenase-Deficient Females

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide. Detection of heterozygously deficient females can be difficult as residual activity in G6PD-sufficient red blood cells (RBCs) can mask deficiency. In this study, we compared accuracy of 4 methods for detection of G6PD deficiency in females. Blood samples from females more than 3 months of age were used for spectrophotometric measurement of G6PD activity and for determination of the percentage G6PD-negative RBCs by cytofluorometry. An additional sample from females suspected to have G6PD deficiency based on the spectrophotometric G6PD activity was used for measuring chromate inhibition and sequencing of the G6PD gene. Of 165 included females, 114 were suspected to have heterozygous deficiency. From 75 females, an extra sample was obtained. In this group, mutation analysis detected 27 heterozygously deficient females. The sensitivity of spectrophotometry, cytofluorometry, and chromate inhibition was calculated to be 0.52 (confidence interval [CI]: 0.32-0.71), 0.85 (CI: 0.66-0.96), and 0.96 (CI: 0.71-1.00, respectively, and the specificity was 1.00 (CI: 0.93-1.00), 0.88 (CI: 0.75-0.95), and 0.98 (CI: 0.89-1.00), respectively. Heterozygously G6PD-deficient females with a larger percentage of G6PD-sufficient RBCs are missed by routine methods measuring total G6PD activity. However, the majority of these females can be detected with both chromate inhibition and cytofluorometry.

Platelet storage performance is consistent by donor: a pilot study comparing "good" and "poor" storing platelets

BACKGROUND

In retrospective studies, it has been shown that differences in storage variables of platelet (PLT) concentrates (PCs) are partially donor dependent. It was our aim to prospectively determine the donor effect on PLT quality.

STUDY DESIGN AND METHODS

Based on quality control data of outdated apheresis PCs, male donors were selected with at least one PC with a pH value of more than 7.0 ("good," n = 6) or one PC with a pH value of less than 6.7 ("poor," n = 6) on Day 8. These donors donated a PC (Trima Accel, Terumo) and completed a short questionnaire about their health and lifestyle. PCs were stored for 12 days and analyzed at regular intervals for in vitro quality.

RESULTS

Donor characteristics were comparable, except that zero of six good and four of six poor donors reported high blood pressure and/or high cholesterol/fat and/or use of medicines. Lactate production in good PCs was lower than that in poor PCs (0.09 ± 0.03 mmol/day/10¹¹ PLTs vs. 0.13 ± 0.04 mmol/day/10¹¹ PLTs, p < 0.05) resulting in a higher pH from Day 5 onward. At the end of storage, the good PCs showed lower CD62P expression, lower phosphatidylserine exposure, and higher mitochondrial membrane potential. PLT functional properties were only slightly different. Despite having lower pH, the poor PCs also fulfilled European Guidelines during 7-day storage.

CONCLUSION

Platelet storage performance is consistent when donors are dichotomized as having good or poor storing PLTs. Metabolic differences are perhaps due to different functionality of the mitochondria. More research is needed to establish the underlying causes and the implications for donors and blood products.

Transfusion of 35-day-stored red blood cells does not alter lipopolysaccharide tolerance during human endotoxemia

BACKGROUND

Transfusion-related immunomodulation (TRIM) encompasses immunosuppressive and proinflammatory effects induced by red blood cell (RBC) transfusion. Changes that occur during storage in the RBC product have been hypothesized to underlie TRIM, mediated by tolerance of toll-like receptors (TLR). We investigated whether transfusion of 35-day-stored autologous RBCs alters cytokine production in response to stimulation with lipopolysaccharide (LPS) or lipotheic acid (LTA), in a clinically relevant model of endotoxemia.

STUDY DESIGN AND METHODS

Eighteen volunteers received 2 ng/kg LPS intravenously, followed by normal saline or 2- or 35-day-stored autologous RBC transfusion. Before LPS, before transfusion, and 6 hours after transfusion blood was collected to measure cytokine gene expression. Whole blood was used for ex vivo stimulation with LPS and LTA, after which cytokine levels were measured with enzyme-linked immunosorbent assay.

RESULTS

In vivo LPS induced a biphasic response in cytokine mRNA with peak values 2 hours after LPS infusion. Storage time of RBC transfusion did not influence cytokine mRNA levels. In vivo infusion of LPS resulted in tolerance for ex vivo stimulation with LPS and LTA. However, transfusion of either fresh or stored RBCs did not further affect the capacity to produce cytokines after ex vivo stimulation.

CONCLUSION

In a clinically relevant model of human endotoxemia, autologous transfusion of 35-day-stored RBCs does not influence cytokine mRNA levels nor does it change the capacity of white blood cells in whole blood to produce cytokines after ex vivo stimulation with LPS or LTA.

The effect of prefreeze rejuvenation on postthaw storage of red blood cells in AS-3 and SAGM

BACKGROUND

We investigated whether improving the metabolic status of red blood cell concentrates before freezing could extend the postthaw shelf life beyond 14 days while still meeting the requirements for hemolysis (0.8%) and total adenylate (>82% of original values).

STUDY DESIGN AND METHODS

At Day 8 after collection, four leukoreduced red blood cell concentrates in saline-adenine-glucose-mannitol (SAGM) were pooled, mixed, and split (n = 4). Of these concentrates, two were rejuvenated in Rejuvesol. In addition, two leukoreduced red blood cell concentrates in phosphate-adenine-glucose-guanosine-gluconate-mannitol (PAGGGM) were pooled, mixed, and split at Day 8 after collection (n = 4). All concentrates were glycerolized, frozen, and stored for at least 2 weeks at -80°C. After thawing and deglycerolization, from each pair, one red blood cell concentrate was resuspended in SAGM, and one was suspended in AS-3. During postthaw storage at 2 to 6°C for 35 days, all concentrates were sampled weekly and analyzed for hematologic, metabolic, and morphologic parameters.

RESULTS

Both Rejuvesol and PAGGGM treatment produced increased adenosine triphosphate and total adenylate and 2,3-diphosphoglycerate levels compared with untreated red blood cell concentrates. Regardless of prefreeze Rejuvesol or PAGGGM treatment, postthaw hemolysis remained below 0.8% during 7 days in SAGM and during 35 days in AS-3. At Day 35 of postthaw storage in AS-3, total adenylate in nonrejuvenated red blood cell concentrates had decreased to 72% of the original values; whereas, in prefreeze Rejuvesol-treated and PAGGGM-treated concentrates, adenylate values were still were at 101% and 98%, respectively.

CONCLUSION

Based on maximum allowable hemolysis of 0.8% and total adenylate content greater than 82% of the original value, thawed, prefreeze Rejuvesol-treated or PAGGGM-treated red blood cell concentrates can be stored for 35 days at 2 to 6ºC in AS-3.

Transfusion of 35-day stored red blood cells does not result in increase of plasma non-transferrin bound iron in human endotoxemia

BACKGROUND

Transfusion of a single unit of stored red blood cells (RBCs) has been hypothesized to induce supra-physiological levels of non-transferrin bound iron (NTBI), which may enhance inflammation and act as a nutrient for bacteria. We investigated the relation between RBC storage time and iron levels in a clinically relevant "two-hit" human transfusion model.

STUDY DESIGN AND METHODS

Eighteen healthy male volunteers (ages 18-35 years) were infused with 2 ng lipopolysaccharide (LPS)/kg to induce systemic inflammatory response syndrome. Two hours later, each participant received either 1 unit of 2-day stored (2D) autologous RBCs, 35-day stored (35D) autologous RBCs, or an equal volume of saline. Every 2 hours up to 8 hours after LPS infusion, hemoglobin, hemolysis parameters, and iron parameters, including NTBI, were measured.

RESULTS

Transfusion of both 2D and 35D RBCs caused increases in hemoglobin, plasma iron, and transferrin saturation; whereas levels remained stable in the saline group. Transfusion of 35D RBCs did not result in hemolysis nor did it lead to increased levels of NTBI compared with 2D RBCs or saline. LPS induced increases in ferritin, haptoglobin, bilirubin, and lactate dehydrogenase that were similar in all three groups.

CONCLUSION

We conclude that 35D autologous RBCs do not cause hemolysis or increased levels of NTBI during human endotoxemia.

Clearance of stored red blood cells is not increased compared with fresh red blood cells in a human endotoxemia model

BACKGROUND

It is thought that the clearance of transfused red blood cells (RBCs) is related both to the storage time of the transfusion product and to the inflammatory status of the recipient. We investigated these effects in a randomized, "two-hit," healthy volunteer transfusion model, comparing autologous RBCs that were stored for 35 days with those that were stored for 2 days.

STUDY DESIGN AND METHODS

Healthy male volunteers donated 1 unit of autologous RBCs either 2 days (2D) or 35 days (35D) before the study date. The experiment was started by infusion of 2 ng/kg lipopolysaccharide ("first hit"). Two hours later, the stored RBCs ("second hit") were reinfused, followed by the labeling of RBCs with biotin. Clearance of biotin-labeled RBCs (BioRBCs) was measured during the 5-hour posttransfusion endotoxemia period along with measurements of phosphatidylserine (PS) exposure, lactadherin binding, and expression of CD47 (cluster of differentiation 47; a transmembrane protein encoded by the CD47 gene).

RESULTS

In the 2D stored RBCs group, 1.5% ± 3.4% of infused BioRBCs were cleared from the circulation 5 hours posttransfusion versus 4.8% ± 4.0% in the 35D stored RBCs group (p = 0.1). There were no differences in PS exposure, lactadherin binding, or CD47 expression between fresh and stored RBCs or between pretransfusion and posttransfusion measurements.

CONCLUSION

Our study shows a low clearance of RBCs even during endotoxemia. Furthermore, short-term clearance of BioRBCs during endotoxemia was not related to storage duration. Consistent with these observations, PS exposure, lactadherin binding, and CD47 expression did not differ between 2D and 35D stored cells before or after transfusion. We conclude that, in the presence of endotoxemia, clearance of 35D stored autologous RBCs is not increased compared with 2D stored fresh RBCs.