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Vitally essential red fluids like packed cells and red wine are seriously influenced in quality when stored over prolonged periods. In the case of red cell concentrates, the resulting storage lesion has particular significance in perioperative medicine. We hypothesized that, in contrast, aging rather improves the properties of red wine in several ways. A translational approach, including (I) in vitro experiments, (II) a randomized, blinded crossover trial of acute clinical effects, and (III) a standardized red wine blind tasting was used. Three monovarietal wines (Cabernet Sauvignon, Chianti, Shiraz) in three different vintages (range 2004–2016), each 5 years different, were assessed. Assessments were performed at a German university hospital (I, II) and on a garden terrace during a mild summer evening (III). Young wines induced cell stress and damage while significantly reducing cytoprotective proteins in HepG2 hepatoma cells. Sympathetic activity and multitasking skills were altered depending on wines’ ages. Hangovers tended to be aggravated by young red wine. Aged variants performed better in terms of aroma and overall quality but worse in optical appearance. We found no evidence for a red wine storage lesion. However, we plead for consensus-based guidelines for proper storage, as it is common in clinical medicine.

Objectives The aim of this study was to compare the characteristics of fresh and stored feline red blood cells (RBCs) after passage through an 18 μm microaggregate filter. Methods Nine cats were recruited for a single blood donation using an open collection system. A simulated transfusion using a syringe driver and microaggregate filter was performed over 2 h with half the blood on the day of donation and the other half after 35 days of storage. Differences in haematological parameters, haemolysis percentage and osmotic fragility (OF) were compared on the day of donation pre-filter passage (D0–) vs day of donation post-filter (D0+) or day 35 storage pre-filter (D35–) and post-filter (D35+). Blood was cultured at D0+ and D35+. Results There were no statistically significant differences in the D0– vs D0+ comparisons. There were statistically significant ( P Conclusions and relevance Fresh RBCs exhibited no in vitro evidence of injury following passage through an 18 μm microaggregate filter. Increased MCH was observed in the stored blood and may represent haemolysis induced by the filter. All other changes can be explained by storage lesion rather than filter passage. The findings highlight the importance of blood banking quality controls and the need for further research to assess the effects of transfusion technique, specifically filter passage, on storage lesion-affected feline blood.

RBC transfusions are a life-saving procedure, aiding both chronic and acute patients in restoring tissue oxygenation. The ability to store collected RBC units for prolonged periods has been one of the most transformative advances in medicine, significantly improving the reliability and the speed of access to blood. However, RBCs undergo a number of metabolic, structural, and biochemical changes during storage, collectively known as the storage lesion, that is detrimental to the quality of the RBC. A major challenge is the ability to evaluate the extent of the storage lesion, and thus the quality of the stored RBC unit directly prior to transfusion. The storage lesion can directly or indirectly reduce the ability of the RBC to deform through the small openings in the microvasculature. Rigid RBCs pose a risk of sequestration in capillaries, impeding blood flow and reducing tissue oxygenation, and are more likely to be cleared out by endothelial macrophages. Studies have shown that there is a loss in RBC deformability during storage and that the rate of RBC deformability loss is donor-dependent. Thus, RBC deformability can be a valuable and reliable biophysical marker of RBC unit quality. Currently, there is a need for a reliable measurement technique that is repeatable and sensitive enough to observe individual differences in RBC deformability in healthy donors, to enable quality control testing of RBC units. We have developed the microfluidic ratchet device, which sorts RBCs based on their deformability, allowing the measurement of both rigid and deformable sup-populations of RBCs within the sample, and generating a unique deformability curve. Here, we use this assay to predict the quality of stored RBC units. We assessed the deformability of 14 healthy donor RBC units through 8 weeks of cold storage at 4°C, which is 2 weeks beyond the Canadian Blood Services approved 6-week standard in Canada. We measured RBC deformability, standard hematological parameters (MCV, MCHC, MCH, and RDW), and hemolysis levels at the time of RBC unit manufacture (week 0), followed by weeks 2, 4, 6, and 8. The microfluidic ratchet device operates by forcing RBCs to deform and travel through rows of tapered constrictions. Constriction size changes from 7.5 to 1.5 µm and is reflective of the microvasculature and vessel opening sizes encountered by RBCs in circulation. RBCs are sorted into 12 distinct outlets based on their deformability. Distribution of RBCs in outlets 1-12 can be quantified and used to calculate the cumulative distribution curve. The cumulative distribution curve provides a distinct deformability signature of each individual RBC sample, which can be defined as rigidity score (RS). RS provides an easy metric to compare the changes in RBC deformability throughout storage (ΔRS) in a single donor as well as across multiple donors. We show that there are both donor- and sex-specific differences in the RBC deformability signatures of stored RBC units. We observed significant inter-donor variability in RBC deformability measured on the day of the RBC unit manufacture, where male donors showed a more stable RBC deformability range (n=8, RS=3.00±0.18) compared to female donors (n=6, RS= 3.29±0.48). The average RS scores were stable between weeks 0-2 (ΔRS 0.07) and showed a reduction in deformability between weeks 1-6 (ΔRS 0.35), with the greatest loss seen between weeks 6-8 (ΔRS 0.42) of cold storage. Interestingly, the response to cold storage is variable, with ΔRS 0.22 to 0.90, suggesting that some donors are more susceptible to storage related changes in RBC deformability than others. Notably, the change in RS over time was donor-specific and did not correlate with RBC deformability at week 0. The majority of RBCs from male donors (ΔRS 0.485, p The ability to profile RBC deformability at the individual blood bag level may help identify more stable RBCs for use in chronic and sensitive patients, or RBC units that can be safely stored beyond the 6-week storage window. Disclosures No relevant conflicts of interest to declare.

Storage lesions in red blood cells (RBCs) hinder efficient circulation and tissue oxygenation. The absence of flow mechanics and gas exchange may contribute to this problem. To test if in vitro compensation of flow mechanics and gas exchange helps RBC recovery, three-dimensional polydimethylsiloxane (PDMS) porous structures were fabricated with a sugar mould, simulating lung alveoli. RBC suspensions were passed through the porous structure cyclically, simulating in vivo blood circulation. Acid-base indices, partial gas pressures, ions, glucose and RBC indices were analyzed. An atomic force microscope was used to investigate local mechanical properties of intact RBCs. RBCs suspensions that passed through the porous structures had a higher pH and oxygen partial pressure, and a lower potassium concentration and carbon dioxide partial pressure. Meantime they had better biochemical properties relative to static samples, namely, they exhibited a more homogenous distribution of Young's Modulus. RBCs that passed through a PDMS porous structure were healthier than static ones, giving hints to prevent RBC storage lesions.

The thrombocyte concentrate (TC) preparation process through its storage affects the platelets contained inside. The contaminating leukocytes in TC is an important factor implicated in storage lesion on TC during storage. Leukodepletion is a method to reduce contaminant leukocytes. Myeloperoxidase (MPO) is an enzyme produced by polymorphonuclear cells that have the potential to change structure and function of platelets when there is interaction between them during storage. The aim of this study is assessing the difference in myeloperoxidase level of TC based on its preparation method (leukodepleted and non-leukodepleted) and time storage. A cross-sectional observational study was conducted at the Blood Transfusion Services Unit, Dr. Sardjito hospital, Yogyakarta from April to December 2014. Thrombocyte Concentrate products was grouped based on storage time (≤ and >72 hours) and preparation method (leukodepleted and non-leukodepleted), their MPO was then measured. Mean difference in each group was analyzed using ANOVA test and post hoc test with statistical significance level of p < 0.05. There were 64 eligible subjects, consisted of 29 leukodepleted TCs and 35 non-leukodepleted TCs, based on their storage time, 31 TCs had ≤72 hours storage time and the other 33 TCs > 72 hours. There were significantly lower median MPO level in ≤72 hours TCs than > 72 hours in non-leukodepleted TC group (13.23 ± 6.47 ng/mL vs 15.58 ± 7.82 ng/mL; p = 0.017). In TC group with more than 72 hours storage time, median MPO level in non-leukodepleted was significantly higher than leukodepleted TC (15.58 ± 7.82 ng/mL vs. 11.11 ± 3.97 ng/mL; p = 0,001). Myeloperoxidase level was lower in non-leukodepleted TC group with ≤ 72 hours than > 72 hours storage time. Furthermore, the MPO level was higher in leukodepleted TC than non-leukodepleted TC in > 72 hours storage time.

Stored red blood cells undergo morphological and biochemical changes with increased storage time, commonly refferred as the storage lesion, reduced integrity of erythrocyte membrane, causing hemolysis and increased free plasma hemoglobin level. Nitric Oxide (NO) is an endogenous vasodilator with the major role in vascular and blood flow regulation. Accumulation of free hemoglobin (fHb) during storage RBC hemolysis is thought to be correlated with elevated NO consuming causes low NO level that significantly impair endothelial function. This study aim to was to analyze the correlation of free Hb and plasma nitric oxide level during PRC storage period in the blood bank. This research was an analytic study with a cross-sectional design to 14 unit PRC those were stored in Dr. M. Djamil Padang Hospital Blood Bank. The study was conducted from May 2016 to August 2017. The assay was performed for 28 days of storage with one week intervals. Free plasma hemoglobin and NO level were analyzed by cyanmethemoglobin and colorimetry method respectively. Spearman test was used to access the correlation between free Hb level and nitric oxide plasma with p

Red blood cell (RBC) storage in the blood bank is characterized by the progressive loss of metabolic regulation, a phenomenon that targets energy and antioxidant metabolism; While the progression of the storage lesion is inevitable, the rate at which this phenomenon occurs varies from donor to donor; Red blood cells from some donors at the end of storage are metabolically superior to RBCs from other donors at the beginning of storage, suggesting that the age of blood alone may not be a sufficiently accurate predictor of stored blood quality; and Animal studies and large-scale omics screening in blood donors have helped identify mechanistic contributors to the metabolic heterogeneity of stored blood units.

Background: The use and benefit of fresh blood and leuco-reduced blood for critically ill patients has been inconclusive. In this study we have tried to observe the same, in patients admitted to intensive care unit. Study Design and Methods: Prospective study was done to observe the effect of transfusion in critically ill patients in a tertiary care hospital. Clinical condition in cases and controls was assessed with the help of Simplified Acute Physiology Score II scoring tool. Clinical outcome among patients who received blood was compared using two cutoffs, 14 and 21 days of shelf life to delineate fresh from old blood. Length of hospital stay, length of stay in ICU, number of days on ventilator and number of hospital acquired infections were used as the surrogate markers for morbidity. Results: Of the 558 critically ill patients admitted during the study period, 427 received (cases) while 131 did not receive the transfusion (controls). Mean SAPS II scores of cases and controls were comparable. We observed a significantly higher rate of mortality among patients who received RBC units over 21 days. However morbidity parameters were affected even when the cutoff of 14 days is considered. Buffy-coat reduced blood did not influence the outcome in the study group. Conclusion: Critically ill patients may be prioritized for receiving fresher units of packed red cells preferably less than 21 days old. Transfusion is an independent risk factor for morbidity. Hence the risk to benefit ratio should be carefully assessed for every red cell transfusion in critically ill patients.

Background Parachute airdrop offers a rapid transfusion supply option for humanitarian aid and military support. However, its impact on longer-term RBC survival is undocumented. This study aimed to determine post-drop quality of RBCs in concentrates (RCC), and both RBCs and plasma in whole blood (WB) during subsequent storage. Study design and methods Twenty-two units of leucodepleted RCC in saline, adenine, glucose, mannitol (SAGM) and 22 units of nonclinical issue WB were randomly allocated for air transportation, parachute drop, and subsequent storage (parachute), or simply storage under identical conventional conditions (4 ± 2°C) (control). All blood products were 6-8 days post-donation. Parachute units were packed into Credo Cubes, (Series 4, 16 L) inside a PeliCase (Peli 0350) and rigged as parachute delivery packs. Packs underwent a 4-h tactical flight (C130 aircraft), then parachuted from 250 to 400 ft before ground recovery. The units were sampled aseptically before and after airdrop at weekly intervals. A range of assays quantified the RBC storage lesion and coagulation parameters. Results Blood units were maintained at 2-6°C and recovered intact after recorded ground impacts of 341-1038 m s-2 . All units showed a classical RBC storage lesion and increased RBC microparticles during 42 days of storage. Fibrinogen and clotting factors decreased in WB during storage. Nevertheless, no significant difference was observed between Control and Parachute groups. Air transportation and parachute delivery onto land did not adversely affect, or shorten, the shelf life of fresh RBCs or WB. Discussion Appropriately packaged aerial delivery by parachute can be successfully used for blood supply.

Randomized controlled trials (RCTs) are reporting no difference in mortality when older v. fresher blood is transfused, yet the biology of red cell aging (storage lesions) in the blood bank shows multiple effects. The contrast of cellular biologic changes of cells removed from circulation, then stored versus outcome research is important. The difference in conclusions from these research avenues drives practice. Many physicians may be confused in light of a Cleveland Clinic retrospective study that created controversy over outcomes, after older blood was transfused. That paper sparked public hearings held by the U.S. Food and Drug Administration (FDA). Widely disparate results exist regarding the biology of aged stored blood, retrospective outcome data, and RCTs. This review poses the question of whether the RCTs to date have been designed with hypotheses based upon the findings of the biology. The RCTs have not utilized non-inferiority design- what is required for proving a negative. Therefore, it remains unclear, if claims, being made today, that age of stored blood does not make a difference are scientifically valid. In the end, much work is yet to be done. Furthermore, no RCTs have been conducted comparing the use of stored blood (any age) to the use of best practices in patient blood management to avoid transfusion altogether, but that is a different question.

The red blood cell (RBC) storage lesion is a series of morphological, functional and metabolic changes that RBCs undergo following collection, processing and refrigerated storage for clinical use. Since the biochemical attributes of the RBC unit shifts with time, transfusion of older blood products may contribute to cardiac complications, including hyperkalemia and cardiac arrest. We measured the direct effect of storage age on cardiac electrophysiology and compared with hyperkalemia, a prominent biomarker of storage lesion severity. Donor RBCs were processed using standard blood banking techniques. The supernatant was collected from RBC units (sRBC), 7-50 days post-donor collection, for evaluation using Langendorff-heart preparations (rat) or human stem-cell derived cardiomyocytes. Cardiac parameters remained stable following exposure to ‘fresh’ sRBC (day 7: 5.9+0.2 mM K+), but older blood products (day 40: 9.7+0.4 mM K+) caused bradycardia (baseline: 279±5 vs day 40: 216±18 BPM), delayed sinus node recovery (baseline: 243±8 vs day 40: 354±23 msec), and increased the effective refractory period of the atrioventricular node (baseline: 77+2 vs day 40: 93+7 msec) and ventricle (baseline: 50+3 vs day 40: 98+10 msec) in perfused hearts. Beating rate was also slowed in human cardiomyocytes after exposure to older sRBC (−75+9%, day 40 vs control). Similar effects on automaticity and electrical conduction were observed with hyperkalemia (10-12 mM K+). This is the first study to demonstrate that ‘older’ blood products directly impact cardiac electrophysiology, using experimental models. These effects are likely due to biochemical alterations in the sRBC that occur over time, including, but not limited to hyperkalemia. Patients receiving large volume and/or rapid transfusions may be sensitive to these effects.New & noteworthyWe demonstrate that red blood cell storage duration time can have downstream effects on cardiac electrophysiology, likely due to biochemical alterations in the blood product. Hyperkalemia and cardiac arrest have been reported following blood transfusions, but this is the first experimental study to show a direct correlation between storage duration and cardiac function. Infant and pediatric patients, and those receiving large volume and/or rapid transfusions may be sensitive to these effects.

Storage lesion is a critical issue facing transfusion treatments, and it adversely affects the quality and viability of stored red blood cells (RBCs). RBC deformability is a key indicator of cell health. Deformability measurements of each RBC unit are a key challenge in transfusion medicine research and clinical haematology. In this paper, a numerical study, inspired from the previous research for RBC deformability and morphology predictions, is conducted for the first time, to investigate the deformability and morphology characteristics of RBCs undergoing storage lesion. This study investigates the evolution of the cell shape factor, elongation index and membrane spicule details, where applicable, of discocyte, echinocyte I, echinocyte II, echinocyte III and sphero-echinocyte morphologies during 42 days of in-vitro storage at 4 &deg, C in saline-adenine-glucose-mannitol (SAGM). Computer simulations were performed to investigate the influence of storage lesion-induced membrane structural defects on cell deformability and its recoverability during optical tweezers stretching deformations. The predicted morphology and deformability indicate decreasing quality and viability of stored RBCs undergoing storage lesion. The loss of membrane structural integrity due to the storage lesion further degrades the cell deformability and recoverability during mechanical deformations. This numerical approach provides a potential framework to study the RBC deformation characteristics under varying pathophysiological conditions for better diagnostics and treatments.

Author(s): Williams, Alexander T; Jani, Vivek P; Nemkov, Travis; Lucas, Alfredo; Yoshida, Tatsuro; Dunham, Andrew; D'Alessandro, Angelo; Cabrales, Pedro | Abstract: BackgroundResuscitation from hemorrhagic shock (HS) by blood transfusion restores oxygen (O2) delivery and provides hemodynamic stability. Current regulations allow red blood cells (RBCs) to be stored and used for up to 42 days. During storage, RBCs undergo many structural and functional changes. These storage lesions have been associated with adverse events and increased mortality after transfusion, increasing the need for improved RBC storage protocols. This study evaluates the efficacy of anaerobically stored RBCs to resuscitate rats from severe HS compared with conventionally stored RBCs.Methods and resultsRat RBCs were stored under anaerobic, anaerobic/hypercapnic, or conventional conditions for a period of 3 weeks. Hemorrhage was induced by controlled bleeding, shock was maintained for 30 min, and RBCs were transfused to restore and maintain blood pressure near the prhemorrhage level. All storage conditions met current regulatory 24-h posttransfusion recovery requirements. Transfusion of anaerobically stored RBCs required significantly less RBC volume to restore and maintain hemodynamics. Anaerobic or anaerobic/hypercapnic RBCs restored hemodynamics better than conventionally stored RBCs. Resuscitation with conventionally stored RBCs impaired indices of left ventricular cardiac function, increased hypoxic tissue staining and inflammatory markers, and affected organ function compared with anaerobically stored RBCs.ConclusionsResuscitation from HS via transfusion of anaerobically stored RBCs recovered cardiac function, restored hemodynamic stability, and improved outcomes.

Background Red blood cell (RBC), which is the most commonly transfused blood component, due to its ability to save a life in absence of any other blood components, can be stored up to maximum 6 weeks by following standard preservation procedure. During storage, RBC undergoes various biophysical and biochemical changes (commonly known as storage lesion) for which blood transfusion with “old RBC” shows a lot of clinical problems especially relevant to critically ill patients. Recent research on S-nitrosylation of haemoglobin to improve oxygen delivery of banked blood revealed the important role of nitric oxide (NO) in protecting storage lesion. Materials and methods In the present study, we used various “NO donating” chemicals with different NO release dynamics and chemistries in RBC storage cocktails to test the effects of NO on storage lesion. Changes in different storage markers were evaluated after 7 days storage of pre-treated RBC. Results All the NO donors have shown protection against hemolysis. However, S-nitroso glutathione (GSNO) ranks first in shielding RBCs from storage lesion and additionally, it helps in elevating the value of 2, 3-di phosphoglycerate (2, 3-DPG), improving the RBC membrane fluidity and decreasing the adhesion towards endothelial monolayer. Discussion Present study reveals that NO released from NO donors confers protection against storage lesions of the RBC. Further, the study confirms that pre-treatment with GSNO, a NO donor and a nitrosylating agent, ensures the best protection to RBC during low temperature storage, when compared to other NO donor treatments.

BACKGROUND Gamma irradiation of red blood cells (RBCs) is well recognized to exacerbate storage lesion formation, but the effect of storage after irradiation on in vivo oxygen delivery capacity of transfused RBCs is currently not known. STUDY DESIGN AND METHODS In 24 preterm infants with anemia receiving nonurgent transfusion of irradiated RBCs, we examined cerebral regional tissue oxygenation (crSO2 ) and time spent with peripheral arterial saturation (SpO2 ) less than 88%. Physiologic data were obtained immediately before, immediately after, and 5 days after transfusion. RESULTS We observed linear negative moderate correlations between time since irradiation and the magnitude of change in crSO2 (r = -0.60; 95% CI, -0.81 to -0.27; p = 0.0018) and time spent with SpO2 of less than 88% (r = -0.42; 95% CI, -0.71 to 0.003; p = 0.04) immediately after transfusion. In infants (n = 9) who received fresher RBCs (irradiated

Caesar Oyet, Benson Okongo, Richard Apecu Onyuthi, Enoch Muwanguzi Department of Medical Laboratory Sciences, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda Background: Blood transfusion with allogeneic blood products is a common medical intervention to treat anemia or prepare patients for surgical procedures. Generally, the blood units are secured and stored prior to expected transfusion. During storage, a number of biochemical changes occur (generally known as storage lesion), which can affect the efficacy of blood transfusion. The aim of the study was to evaluate the biochemical changes that occur in blood units during storage and to project the impact of these changes on transfusion.Methods: The study protocol was approved by the Faculty of Medicine Research Ethics committee of Mbarara University of Science and Technology. A total of 200 blood recipients were categorized into two study arms: group I received fresh blood (n=100) and group II received old blood (n=100), who were formally consented and recruited consecutively. A total of 2mL of venous blood was collected from each participant in EDTA tubes before transfusion (for pre-transfusion hemoglobin [Hb] estimation) and after transfusion (for post-transfusion Hb estimation). Each crossmatched unit was sampled to collect plasma for pH, lactate and potassium assays. Data were analyzed with STATA version 12.0.Results: A total of 200 blood transfusion recipients aged 1–60years were enrolled in the study. Up to 60% of the participants were females. The pH of the stored blood dropped from 7.4 to 7.2 in the first 3days to ~7.0 by day 11 and to 14days has reduced efficacy with increased markers of red cell storage lesion such as increased potassium level, lactate and fall in pH. These lesions increase the length of hospital stay. Keywords: blood transfusion, storage lesion, biochemical changes, anemia, Uganda

Background: Extracellular vesicles (EVs) in blood products are potential effectors of inflammation and coagulation after transfusion. The aim of this study was to assess the impact of different blood manufacturing methods and duration of hypothermic storage on the EV subpopulations in relation to other in vitro quality parameters of red blood cell concentrate (RCC) products. Methods: RCCs were produced using whole blood filtration (WBF) or red cell filtration (RCF) (n = 12/method), refrigerated for 43 days, and evaluated for EV size profile and concentration, red cell deformability, ATP and 2,3-DPG, hemolysis, and hematological indices. Results: The total number of EVs increased significantly with storage in both methods, and WBF-RCCs contained the higher numbers of EVs compared to RCF-RCCs. The concentration of small EVs was greater in WBF-RCCs versus RCF-RCCs, with difference between the two methods observed on day 43 of storage (p = 0.001). Throughout storage, significant decreases were identified in ATP, 2,3-DPG, and EImax, while an increase in hemolysis was observed in both RCC products. Conclusion: The dynamic shift in the size and concentration of the EV subpopulations is dependent on the blood manufacturing method and length of storage. Better understanding of the potential clinical implications of these heterogeneous populations of EVs are needed.

With the development of several 'vein-to-vein' databases, which capture data on the entire donor-recipient continuum and link this data to health outcomes, there has been an increasing number of studies investigating the health effects of all aspects of the practice of transfusion medicine. The Scandinavian Donations and Transfusions (SCANDAT) database is one of several such databases, which includes all electronically available data on blood donors, donations and transfusions since the late 1960s in Sweden and the early 1980s in Denmark. The SCANDAT database has been used to characterise disease occurrence among blood donors and transfused patients, as well as to investigate possible health effects of blood donations, aspects of transfusion care and possible transfusion transmission of disease. Recent publications include studies on recipient mortality associated with the storage lesion, studies on the effects of donor demographics on patient mortality and health effects of frequent blood donation. Although this research approach is clearly very powerful, the appropriate analysis of such real-world data is complex and requires close methodological attention. The purpose of this review is to present some of the research conducted within the SCANDAT collaboration. We hope more international collaboration may help improve our understanding of the important remaining questions about donor and recipient health.

Objectives This study describes the biochemical changes – also known as the storage lesion – that occur in canine packed red blood cells during ex vivo storage. Materials and Methods Ten 125-mL units of non-leuco-reduced packed red blood cells in citrate phosphate dextrose adenine were obtained from a commercial blood bank within 24 hours of donation. Samples were aseptically collected on days 1, 4, 7, 14, 28, 35 and 42 for measurement of sodium, potassium, chloride, lactate, glucose, pH and ammonia concentrations. All units were cultured on day 42. Friedman's repeated measures test with Dunn's multiple comparison test was used for non-parametric data. A repeated-measures analysis of variance with Tukey's multiple comparison test was used for parametric data. Alpha was set to 0·05. Results All analytes changed significantly during storage. The mean ammonia on day 1 (58·14 g/dL) was significantly lower (P

We present a novel automated system for morphology analysis of red blood cells (RBC) under flow. RBC concentrates collected by blood banks for transfusions are stored for periods of up to several weeks, during which time a number of changes occur, collectively termed the storage lesion. Typically the extent of hemolysis is the defining criterion to determine the acceptability of the RBCs for transfusions. Morphological changes are related with biochemical alteration during the storage of RBCs. The typical blood smear procedure for determining such changes is a labor-intensive and potentially biased manual process. The advantage of the flow morphometry system presented here is that it provides fully automated morphological classification of RBCs with large sample numbers in a short time. Our system uses a commercially available flow cell and flow conditions that prevent adhesion of RBCs, thus eliminating the need for blocking agents such as albumin that affect the distribution of cell shapes. Our morphometry results are validated by comparison with standard biochemical assays (hemolysis, ATP) for blood from 17 donors stored under blood bank conditions for 13 weeks. We show that the percentage of spherocytes present can be used to estimate the status of RBC concentrates. © 2017 International Society for Advancement of Cytometry.

Background Prolonged storage of packed red blood cells (pRBCs) induces a series of harmful biochemical and metabolic changes known as the RBC storage lesion. RBCs are currently stored in an acidic storage solution, but the effect of pH on the RBC storage lesion is unknown. We investigated the effect of modulation of storage pH on the RBC storage lesion and on erythrocyte survival after transfusion. Methods Murine pRBCs were stored in Additive Solution-3 (AS3) under standard conditions (pH, 5.8), acidic AS3 (pH, 4.5), or alkalinized AS3 (pH, 8.5). pRBC units were analyzed at the end of the storage period. Several components of the storage lesion were measured, including cell-free hemoglobin, microparticle production, phosphatidylserine externalization, lactate accumulation, and byproducts of lipid peroxidation. Carboxyfluorescein-labeled erythrocytes were transfused into healthy mice to determine cell survival. Results Compared with pRBCs stored in standard AS3, those stored in alkaline solution exhibited decreased hemolysis, phosphatidylserine externalization, microparticle production, and lipid peroxidation. Lactate levels were greater after storage in alkaline conditions, suggesting that these pRBCs remained more metabolically viable. Storage in acidic AS3 accelerated erythrocyte deterioration. Compared with standard AS3 storage, circulating half-life of cells was increased by alkaline storage but decreased in acidic conditions. Conclusions Storage pH significantly affects the quality of stored RBCs and cell survival after transfusion. Current erythrocyte storage solutions may benefit from refinements in pH levels.

Background Storage lesion may explain the rapid clearance of up to 25% of transfused red blood cells (RBCs) in recipients. Several alterations affect stored RBC but a quantitative, whole cell-based predictor of transfusion yield is lacking. Because RBCs with reduced surface area are retained by the spleen, we quantified changes in RBC dimensions during storage. Study design and methods Using imaging flow cytometry we observed the dimension and morphology of RBCs upon storage, along with that of conventional biochemical and mechanical markers of storage lesion. We then validated these findings using differential interference contrast (DIC) microscopy and quantified the accumulation of microparticles (MPs). Results Mean projected surface area of the whole RBC population decreased from 72.4 to 68.4 µm2 , a change resulting from the appearance of a well-demarcated subpopulation of RBCs with reduced mean projected surface (58 µm2 , 15.2%-19.9% reduction). These "small RBCs" accounted for 4.9 and 23.6% of all RBCs on Days 3 and 42 of storage, respectively. DIC microscopy confirmed that small RBCs had shifted upon storage from discocytes to echinocytes III, spheroechinocytes, and spherocytes. Glycophorin A-positive MPs and small RBCs appeared after similar kinetics. Conclusion The reduction in surface area of small RBCs is expected to induce their retention by the spleen. We propose that small RBCs generated by MP-induced membrane loss are preferentially cleared from the circulation shortly after transfusion of long-stored blood. Their operator-independent quantification using imaging flow cytometry may provide a marker of storage lesion potentially predictive of transfusion yield.

Blood banking is an essential aspect of modern medical care. When red blood cells (RBCs) are stored, they become damaged by various chemical processes, such as accumulation of their own waste products and oxidative injury, among others. These processes lead to the development of the RBC storage lesion, a complex condition where the severity is reflected through the morphology of the stored cells. It was hypothesized that Raman spectroscopy could be used to monitor certain structural and compositional changes associated with such ageing effects and that a relationship between these features and traditional morphology (as measured using a morphology index) could be observed. The hypothesis was tested by measuring spectral features associated with hemoglobin oxygenation from dry-fixed smears and liquid RBCs for twenty-nine different donors (combined), and comparing the trends with morphological scoring from seven of these donors. After appropriately fitting the two data sets to either power or linear curves, the oxygenation state was shown to change in a manner that was donor-dependent and that closely tracked morphological changes. This study suggests Raman analysis has promise for providing a rapid and objective measure of the cell quality of stored RBCs through measurements of hemoglobin oxygenation that is comparable to traditional morphological assessment.

Objectives: This study’s aim was to find out that how various biochemical parameters of donor blood are affected during storage. Methods: This cross-sectional study was conducted in hematology Unit of Rehman Medical Institute, Peshawar and Fatimid Foundation, Peshawar Khyber Pakhtunkhwa, over a period of six months from June 2018 to November 2018. This study includes 300 healthy volunteer donors. Analysis of stored blood was done at 0, 3, 7, 14- and 21-days interval. Data were recorded and analyzed in SPSS v 20. A p value of less than 0.05 was taken as significant. Results: Three hundred healthy volunteer donors were included in the study in which 63% were male and 37% were females. Mean age was 26.54±7.3 years with age range from 23-46 years. Out of 300 donors 15.33% were O+, 35.33%, 9.66% B+, 8.33% A+, 7.66% AB+, 7.66% O-, 7% A- and 9% B-. Significant. Changes were observed in serum potassium, LDH, pH, serum chloride, serum sodium and AST levels. (p

Pathogen reduction technologies (PRTs) have been developed to further reduce the current very low risks of acquiring transfusion-transmitted infections and promptly respond to emerging infectious threats. An entire portfolio of PRTs suitable for all blood components is not available, but the field is steadily progressing. While PRTs for plasma have been used for many years, PRTs for platelets, red blood cells (RBC) and whole blood (WB) were developed more slowly, due to difficulties in preserving cell functions during storage. Two commercial platelet PRTs use ultra violet (UV) A and UVB light in the presence of amotosalen or riboflavin to inactivate pathogens' nucleic acids, while a third experimental PRT uses UVC light only. Two PRTs for WB and RBC have been tested in experimental clinical trials with storage limited to 21 or 35 days, due to unacceptably high RBC storage lesion beyond these time limits. This review summarizes pre-clinical investigations and selected outcomes from clinical trials using the above PRTs. Further studies are warranted to decrease cell storage lesions after PRT treatment and to test PRTs in different medical and surgical conditions. Affordability remains a major administrative obstacle to PRT use, particularly so in geographical regions with higher risks of transfusion-transmissible infections.

Background and objectives There is a growing concern for shortage in future blood supply, caused by a predicted decrease in eligible blood donors and simultaneous increase in recipients. Cryopreservation of split red blood cell units could increase stock supply by reducing waste of rare blood. This would be particularly useful in paediatric care where very small volumes often are transfused. The aim of this study was to develop a cryopreservation protocol for split units using the closed-system automated cell processor ACP215, as such protocols are currently missing. Materials and methods Using a pool-and-split design, red blood cell units (N = 8) were glycerolized and frozen, either as standard volume reference units, or further divided into three smaller split units each. After thawing/deglycerolization, the supernatant of the smaller splits was reduced by additional centrifugation, and new SAGM was added to 60% haematocrit. The units were analysed for storage lesion effects up to ten days post-thawing. Results Haemolysis and extracellular potassium ion levels were lower in the split units than in the whole units from day three onwards. The metabolic parameters pH, ATP, glucose and lactate were also lower, though likely caused by lower additive solution pH rather than storage. Conclusion Split units of red blood cells can be successfully cryopreserved using the ACP215. In addition to favourably low haemolysis and potassium, they also have higher haematocrit than corresponding whole units and enable involvement of fewer donors at repeated transfusions. These characteristics are all desirable features in paediatric care.

Red blood cell (RBC) products are produced primarily from whole blood units but may also be collected by apheresis. RBC transfusions are indicated for the treatment of decreased oxygen-carrying capacity in the setting of anemia and decreased RBC mass. RBC products can be modified, such as by leukoreduction, irradiation, and washing, to meet the needs of patients. They are stored for up to 42 days at 1–6°C. During storage the cells undergo changes, termed the storage lesion, the clinical consequences of which are debatable.

The introduction of omics technologies, in particular proteomics and metabolomics in the field of transfusion medicine, has unveiled the complexity of the storage lesion. Even though it is now universally accepted that the storage lesion affects red cell survival upon transfusion and thus, theoretically, the safety and effectiveness of the transfusion therapy, no significant association between storage duration and transfusion outcomes has been observed in any of the large-scale randomized clinical trials performed so far. This disconnection between laboratory and clinical evidence may be in part reconciled by the appreciation of the underlying biological variability among donors and recipients, utterly affecting the severity of the storage lesion and the clinical effects of the transfusion therapy. While in the last few years the transfusion community has been split between those seeing the glass half full or half empty, considerations on the influence of biological variability and prestorage variables (e.g. handling and processing) on the final quality of packed red blood cells have prompted a re-assessment of whether we do really know what is in the glass (the final blood product). Controversy persists between the supporters of the clinical irrelevance of the storage lesion and those questioning the design and statistical power of the evidence-based studies looking for a correlation between storage duration and untoward consequences of transfusion. In the meantime, alternative storage strategies and solutions have been designed that promise to deliver better quality blood products for both factions.

Background Stored red blood cells (RBCs) accumulate biochemical and biophysical changes, known as storage lesion. The aim of this study was to re-challenge current data that anaemia in chronically anaemic haematology patients is not associated with low skeletal muscle tissue oxygen (StO2), and that RBC storage age does not influence the tissue response after ischaemic provocation, using near-infrared spectroscopy. Patients and methods Twenty-four chronic anaemic haematology patients were included. Thenar skeletal muscle StO2 was measured at rest (basal StO2), with vascular occlusion testing (upslope StO2, maximum StO2) before and after transfusion. Results Basal StO2 was low (53% ± 7%). Average RBC storage time was 10.5 ± 3.9 days. Effects of RBC transfusions were as follows: basal StO2 and upslope StO2 did not change significantly; maximum StO2 increased compared to baseline (64 ± 14% vs. 59 ± 10%, p = 0.049). Change of basal StO2, upslope StO2 and maximum StO2 was negatively related to age of RBCs. The decrease of maximum StO2 was predicted (sensitivity 70%, specificity 100%), after receiving RBCs ≥ 10days old. Discussion Resting skeletal muscle StO2 in chronic anaemic patients is low. RBC storage time affects skeletal muscle StO2 in the resting period and after ischaemic provocation.

BACKGROUND Transfusion of platelets (PLTs) is a common therapy in a number of clinical settings. However, it is well understood that there is substantial donor-to-donor variation in how well PLTs store and thus the quality of the products that are transfused. The basis of such variation is poorly understood, and there are limited metrics by which units of PLTs can be assessed for their posttransfusion performance. It has repeatedly been demonstrated that myriad biologic changes take place during PLT storage; however, which of the changes correlate with quality of the stored PLTs and/or are mechanistically involved in PLT function remains undetermined. STUDY DESIGN AND METHODS The current study tested stored PLTs from 21 normal subjects, combining high-resolution metabolomics of stored PLTs with in vivo PLT recoveries and survivals. Both individual analytes and metabolic pathways that correlate with posttransfusion PLT viability were identified. RESULTS Caffeine metabolites were associated with poor PLT recovery; caffeine metabolism was not ongoing in the PLT bag and remained at prestorage levels. Acylcarnitines, particular fatty acid metabolites, and oxidized fatty acids were associated with poor PLT survivals. Of the myriad metabolic changes during PLT storage, these are the first reported metabolic findings to begin distinguishing which changes are of functional importance regarding posttransfusion PLT performance. CONCLUSIONS Together, these findings provide novel mechanistic insights into the functional biology of the PLT storage lesion as well as identifying potential targets for modifying donor environment (e.g., caffeine consumption) and also metrics of quality assessment for stored human PLTs.

BACKGROUND Previous studies have shown that baseline hematologic characteristics concerning or influencing red blood cell (RBC) properties might affect storage lesion development in individual donors. This study was conducted to evaluate whether variation in hemolysis, microparticle accumulation, phosphatidylserine (PS) exposure, and other storage lesion–associated variables might be a function of the prestorage hematologic and biologic profiles of the donor. STUDY DESIGN AND METHODS Ten eligible, regular blood donors were paired and studied before donation (fresh blood) and during storage of RBCs in standard blood banking conditions. Plasma and cellular characteristics and modifications were evaluated by standard laboratory and biochemical or biologic analyses as well as by statistical and network analysis tools. RESULTS Nitrate/nitrite and other bioactive factors exhibited high interdonor variability, which further increased during storage in a donor-specific manner. Storage lesion evaluators, including RBC fragility and PS exposure, fluctuated throughout the storage period in proportion to their values in fresh blood. Donors’ levels of phosphatidylserine exposure and hemoglobin F correlated with stored cells’ mean cell (RBC) Hb concentration, oxidative stress markers, and cellular fragility. DISCUSSION Storage lesion indicators change in an orderly fashion, namely, by following donor-related prestorage attributes. These correlations are illustrated for the first time in “prestorage versus storage” biologic networks, which might help determine the best candidates for in vivo biomarkers of storage quality and provide deeper insight into the apparently complex donor variation effect on the RBC storage lesion.

The storage of red blood cells under standard blood-banking conditions leads to a decline in red cell quality and function known as the red cell storage lesion. These changes are linked to alterations in cellular biochemical processes, biomechanical effects and damage from oxidation. Although storage-related alterations in red cells can be readily measured in the laboratory, the clinical impact of the storage lesion is not as easy to demonstrate. While some immediate differences between fresh and stored cells can be measured, red cells recover in the circulation to some degree upon transfusion with a concomitant reduction in the effect of the storage lesion. The clinical literature is inconsistent with studies arguing that long-term stored red cells have a clinical impact and other studies including recent randomized controlled trials have failed to show any effect of the storage lesion on patient outcomes. Amelioration of the storage lesion will require further development of novel storage processes as well as an increased understanding of the role that donor-specific factors play in product quality.

Platelet units for transfusion purposes are obtained manually from whole blood or by apheresis, in an automated process. In both methods, platelets during storage present a characteristics grouped under the name "storage lesion" that are associated with adverse effects on platelet units. Oxidative stress has been claimed to be one of major causes, leading to activation and apoptosis processes affecting their post transfusion functionality. In this work, we observed an association between apheresis and a reduced presence of oxidative stress and better results in functional markers in stored platelets, compared to manually obtained platelets. Then, apheresis which would ensure a greater number of functional platelets during the 5 days of storage, compared to concentrates obtained from whole blood.

Extracellular vesicles (EVs) have been shown to be involved in various physiological and pathophysiological processes. With respect to Transfusion Medicine, the accumulation of EVs in blood products during hypothermic storage is an indicator of the storage lesion and reportedly correlates with adverse effects after transfusion, including but not limited to immunomodulation, activation of coagulation, endothelial activation, and others. To optimally reduce such an impact on blood product quality degradation and improve post-transfusion outcomes, better methods for detection, enumeration, characterisation by size and phenotype, and functional involvement of EVs in different pathophysiological and physiological processes are required. Currently, Imaging Flow Cytometry (IFC) technology provides the most comprehensive assessment of EV subsets in different body fluids. The unique ability of IFC to detect EVs of 20 nm size by registration of a single pixel of fluorescence signal makes this approach highly promising for comprehensive studies of EVs. In this review, we will focus on the recent breakthrough and advantages of using the ImageStreamX MKII IFC platform for the detection and characterisation of EVs and its future prospects for routine application of IFC in Transfusion Medicine.

The standard practice in blood banks worldwide involves storage of red blood cells (RBCs) in plastic bags until they are needed for transfusion. During storage, the cells gradually degrade in functionality, a condition described as RBC storage lesion. Standard analytical techniques cannot assess the blood quality without breaching the sterility of the transfusion bag. In this study, we employed a commercially available spatially offset Raman spectroscopy (SORS) system using a custom designed protocol to non-invasively explore the biochemical changes in RBC concentrate of healthy donors over a storage period of approximately 42 days in standard transfusion bags, under standard storage conditions. The results reveal an increase in the oxygenation state of haemoglobin over the storage period for all donors, but different profiles for each donor. This study demonstrates the feasibility of acquiring consistent biochemical information relevant to the quality of stored blood, in situ through sealed blood transfusion bags using a commercially available instrument.

Introduction: Stored red blood cells (RBCs) undergo storage lesions involving morphological, physiological and biochemical changes. MicroRNAs (miRNAs) have important functions in cell apoptosis and life processes. Therefore, the aim of this study was to explore potential roles of miRNAs in the damage of stored RBCs. Methods: Blood samples were collected from 13 healthy male O-type donors, and leuko-reduced RBCs were divided into fresh RBC group and 20-day storage RBC group. Results: Eight predicted miRNAs with modified expressions with an intersection ≥ 3 were found dysregulated in the 20-day storage RBC group and involved in apoptosis and senescence signaling pathway: miR-31-5p, miR-196a-5p, miR-203a, miR-654-3p and miR-769-3p were increased, while miR-96-5P, miR-150-5P and miR-197-3p were decreased. Evidence associating miR-31-5p, miR-203a, miR-654 and miR-769 to RBCs or blood in general are not available. Conclusions: Dysregulated miRNAs might represent potential biomarkers to identify storage lesions, and their detection might help to evaluate the quality of stored RBCs.

The proportion of transfused red blood cells (RBCs) that remain in circulation is an important surrogate marker of transfusion efficacy and contributes to predict the potential benefit of a transfusion process. Over the last 50 years, most of the transfusion recovery data were generated by chromium-51 (51Cr)-labeling studies and were predominantly performed to validate new storage systems and new processes to prepare RBC concentrates. As a consequence, our understanding of transfusion efficacy is strongly dependent on the strengths and weaknesses of 51Cr labeling in particular. Other methods such as antigen mismatch or biotin-based labeling can bring relevant information, for example, on the long-term survival of transfused RBC. These radioactivity-free methods can be used in patients including from vulnerable groups. We provide an overview of the methods used to measure transfusion recovery in humans, compare their strengths and weaknesses, and discuss their potential limitations. Also, based on our understanding of the spleen-specific filtration of damaged RBC and historical transfusion recovery data, we propose that RBC deformability and morphology are storage lesion markers that could become useful predictors of transfusion recovery. Transfusion recovery can and should be accurately explored by more than one method. Technical optimization and clarification of concepts is still needed in this important field of transfusion and physiology.

Background During the storage of packed red blood cells (pRBC), packed cell volume (PCV), bacterial contamination and percentage of haemolysis [percentage of free haemoglobin (HGB) in relation to the total HGB] are important quality parameters. Both PCV and haemolysis are indicators of the cellular integrity of stored units. There are no published experimental studies that evaluated these parameters during storage of feline pRBC using SAGM (adenine, dextrose, mannitol and sodium chloride) as the additive solution. The present study aims to (1) evaluate the quality of feline pRBCs stored in SAGM; (2) test for the semi-closed system’s suitability for use and risk of bacterial contamination; (3) establish the maximum storage time that may be appropriate to meet the criteria established by the United States Food and Drug Administration (US-FDA) guidelines for human blood banking; and (4) evaluate the need to calculate the percentage of haemolysis prior to the administration of units stored for more than 4 weeks. Four hundred eighty nine feline pRBC units were analyzed. Bacterial culture, PCV and percentage of haemolysis were determined within 6 h after processing (t0). One hundred and eighty units were re-tested for haemolysis and PCV after 29–35 days of storage (t1) and 118 units after 36–42 days (t2). Results Bacterial contamination was not detected in any pRBC unit. Mean PCV at t0 was 52.25% (SD: ±5.27) and decreased significantly (p

Background During cold storage, some red blood cell (RBC) units age more rapidly than others. Yet, the Food and Drug Administration has set a uniform storage limit of 42 days. Objectives of this review are to present evidence for an RBC storage lesion and suggest that functional measures of stored RBC quality—which we call real age—may be more appropriate than calendar age. Methods During RBC storage, biochemical substances and byproducts accumulate and RBC shape alters. Factors that influence the rate of degradation include donor characteristics, bio-preservation conditions, and vesiculation. Better understanding of markers of RBC quality may lead to standardized, quantifiable, and operationally practical measures to improve donor selection, assess quality of an RBC unit, improve storage conditions, and test efficacy of the transfused product. Results The conundrum is that clinical trials of younger versus older RBC units have not aligned with in vitro aging data; that is, the units transfused were not old enough. In vitro changes are considerable beyond 28 to 35 days, and average storage age for older transfused units was 14 to 21 days. Conclusions RBC product real age varies by donor characteristics, storage conditions, and biological changes during storage. Metrics to measure temporal changes in quality of the stored RBC product may be more appropriate than the 42-day expiration date. Randomized trials and observational studies are focused on average effect, but, in the evolving age of precision medicine, we must acknowledge that vulnerable populations and individuals may be harmed by aging blood.

Red blood cells (RBCs) are stored up to 35-42 days at 2-6 degrees C in blood banks. During storage, the RBC membrane is challenged by energy depletion, decreasing pH, altered cation homeostasis, and oxidative stress, leading to several biochemical and morphological changes in RBCs and to shedding of extracellular vesicles (EVs) into the storage medium. These changes are collectively known as RBC storage lesions. EVs accumulate in stored RBC concentrates and are, thus, transfused into patients. The potency of EVs as bioactive effectors is largely acknowledged, and EVs in RBC concentrates are suspected to mediate some adverse effects of transfusion. Several studies have shown accumulation of lipid raft associated proteins in RBC EVs during storage, whereas a comprehensive phospholipidomic study on RBCs and corresponding EVs during the clinical storage period is lacking. Our mass spectrometric and chromatographic study shows that RBCs maintain their major phospholipid (PL) content well during storage despite abundant vesiculation. The phospholipidomes were largely similar between RBCs and EVs. No accumulation of raft lipids in EVs was seen, suggesting that the primary mechanism of RBC vesiculation during storage might not be raft-based. Nonetheless, a slight tendency of EV PLs for shorter acyl chains was observed.

Transfusions remain a cornerstone of medical therapy in the critically ill patient, with at least 30% of patients in the ICU receiving one or more red blood cell transfusions (Shehata et al. Transfusion 54:2631-9, 2014; Vincent, JAMA 288:1499-507, 2002; Corwin, Crit Care Med 32:39-52, 2004). Our understanding of the biochemical, structural, and functional changes that occurs to red blood cells with storage – also known as the storage lesion – has fueled concerns around transfusion of stored blood. To date, 16 randomized controlled trials across various clinical settings in both the pediatric and adult literature have established that transfusion of red blood cells stored for shorter durations does not reduce the risk of recipient mortality. These studies have also shown that transfusion of long-term stored blood (stored for 36–42 days) is not harmful, and thus, current practice remains appropriate. Interestingly, randomized trials may have raised questions around the safety of “fresh” blood. Building on this body of work, an emerging area of research explores the potential clinical impacts of blood donor age and sex as well as the method of whole blood processing on recipient outcomes.

Background: Recent evidence shows a selective destruction of the youngest circulating red blood cells (neocytolysis) trigged by a drop in erythropoietin levels. Objective: The aim of this study was to evaluate the effect of recombinant human erythropoietin beta on the red blood cell storage lesion and apoptosis indices under blood bank conditions. Methods: Each one of ten red blood cell units preserved in additive solution 5 was divided in two volumes of 100 mL and assigned to one of two groups: erythropoietin (addition of 665 IU of recombinant human erythropoietin) and control (isotonic buffer solution was added). The pharmacokinetic parameters of erythropoietin were estimated and the following parameters were measured weekly, for six weeks: Immunoreactive erythropoietin, hemolysis, percentage of non-discocytes, adenosine triphosphate, glucose, lactate, lactate dehydrogenase, and annexin-V/esterase activity. The t-test or Wilcoxon's test was used for statistical analysis with significance being set for a p-value 6 weeks under blood bank conditions, with persistent supernatant concentrations of erythropoietin during the entire storage period. Adenosine triphosphate was higher in the Erythropoietin Group in Week 6 (4.19 ± 0.05 µmol/L vs. 3.53 ± 0.02 µmol/L; p-value = 0.009). The number of viable cells in the Erythropoietin Group was higher than in the Control Group (77% ± 3.8% vs. 71% ± 2.3%; p-value

During storage, red blood cells (RBC) become more susceptible to hemolysis and it has also been shown that RBC deformability, which is influenced by RBC nitric oxide synthase (RBC-NOS) activity, decreases during blood storage while a correlation between these two parameters under storage conditions has not been investigated so far. Therefore, blood from 15 male volunteers was anticoagulated, leuko-reduced and stored as either concentrated RBC or RBC diluted in saline-adenine-glucose-mannitol (SAGM) for eight weeks at 4°C and results were compared to data obtained from freshly drawn blood. During storage, decrease of RBC deformability was related to increased mean cellular volume and increased cell lysis but also to a decrease in RBC-NOS activation. The changes were more pronounced in concentrated RBC than in RBC diluted in SAGM suggesting that the storage method affects the quality of blood. These data shed new light on mechanisms underlying the phenomenon of storage lesion and reveal that RBC-NOS activation and possibly nitric oxide production in RBC are key elements that are influenced by storage and in turn alter deformability. Further studies should therefore also focus on improving these parameters during storage to improve the quality of stored blood with respect to blood transfusion.