A comparison of biochemical and functional alterations of rat and human erythrocytes stored in CPDA-1 for 29 days: implications for animal models of transfusion

NonFreezable Preservation of Human Red Blood Cells at -8 °C

Red blood cell (RBC) preservation is very important in human health. The RBCs are usually preserved at 4 ± 2 °C without freezing or at a very low temperature (-80 °C or liquid nitrogen) with deep freezing. Herein, non freezable preservation of RBCs at a subzero temperature is reported to prolong the preservation time compared with that at 4 ± 2 °C. By adding glycerol and poly(ethylene glycol) (PEG) (average number molecular weight 400, PEG-400) into the preservation solution, the freezing point is decreased and the hemolysis is kept low. The cell metabolism of stored RBCs at -8 °C is reduced, and the shelf life of RBCs extends up to at least 70 days. At the end of preservation, the pH decreases a little bit to demonstrate the low metabolic rate of RBCs stored at subzero temperatures. After quick washing, the RBC survival rate is ca. 95%. The adenosine triphosphate, 2,3-diphosphoglycerate, and cell deformation ability of the washed RBCs are maintained at a high level, while the malondialdehyde is relatively low, which verifies the high quality of RBCs stored at this condition.

Cellular and Biochemical Effects of Combined X-Ray Radiation and Storage on Whole Blood

Background

Evaluating the impact of ionizing radiation on stored blood is relevant since blood banks are major assets in emergency conditions such as radiation incident/attack. This study aimed to fill our knowledge gap of combined radiation and storage effects on blood.

Methods

Blood collected from 16 anesthetized rats was anticoagulated, aliquoted into storage bags, and assigned to 8 groups using protocols combining storage (1-day vs 3-day 4^oC) plus irradiation (75 Gy vs 0 Gy - control). Bags were positioned inside an X-ray irradiator (MultiRad-350). Complete blood count, differential white blood cell count, biochemistry, and hemostasis were analyzed (≥7 bags/group).

Results

Na⁺, bicarbonate, glucose, and pH significantly reduced, while K⁺, Cl⁻, and lactate increased by storage. Coagulation measures were not significantly altered after radiation. White blood cell count and most cell types were numerically reduced after radiation, but changes were statistically significant only for monocytes. No significant alterations were noted in aggregation or rotational thromboelastometry parameters between irradiated and control.

Conclusions

Evaluating cellular/biochemical parameters aids in assessing stored blood adequacy after radiation. Data suggest that fresh or cold-stored blood can sustain up to 75 Gy without major critical parameter changes and may remain suitable for use in critically ill patients in military/civilian settings.

Deformability of Stored Red Blood Cells

Red blood cells (RBCs) deformability refers to the cells’ ability to adapt their shape to the dynamically changing flow conditions so as to minimize their resistance to flow. The high red cell deformability enables it to pass through small blood vessels and significantly determines erythrocyte survival. Under normal physiological states, the RBCs are attuned to allow for adequate blood flow. However, rigid erythrocytes can disrupt the perfusion of peripheral tissues and directly block microvessels. Therefore, RBC deformability has been recognized as a sensitive indicator of RBC functionality. The loss of deformability, which a change in the cell shape can cause, modification of cell membrane or a shift in cytosol composition, can occur due to various pathological conditions or as a part of normal RBC aging (in vitro or in vivo). However, despite extensive research, we still do not fully understand the processes leading to increased cell rigidity under cold storage conditions in a blood bank (in vitro aging), In the present review, we discuss publications that examined the effect of RBCs’ cold storage on their deformability and the biological mechanisms governing this change. We first discuss the change in the deformability of cells during their cold storage. After that, we consider storage-related alterations in RBCs features, which can lead to impaired cell deformation. Finally, we attempt to trace a causal relationship between the observed phenomena and offer recommendations for improving the functionality of stored cells.

Metabolic rejuvenation upgrades circulatory functions of red blood cells stored under blood bank conditions

BACKGROUND

Red blood cells (RBC) change upon hypothermic conservation, and storage for 6 weeks is associated with the short-term clearance of 15% to 20% of transfused RBCs. Metabolic rejuvenation applied to RBCs before transfusion replenishes energetic sources and reverses most storage-related alterations, but how it impacts RBC circulatory functions has not been fully elucidated.

STUDY DESIGN AND METHODS

Six RBC units stored under blood bank conditions were analyzed weekly for 6 weeks and rejuvenated on Day 42 with an adenine-inosine-rich solution. Impact of storage and rejuvenation on adenosine triphosphate (ATP) levels, morphology, accumulation of storage-induced microerythrocytes (SMEs), elongation under an osmotic gradient (by LORRCA), hemolysis, and phosphatidylserine (PS) exposure was evaluated. The impact of rejuvenation on filterability and adhesive properties of stored RBCs was also assessed.

RESULTS

Rejuvenation of RBCs restored intracellular ATP to almost normal levels and decreased the PS exposure from 2.78% to 0.41%. Upon rejuvenation, the proportion of SME dropped from 28.2% to 9.5%, while the proportion of normal-shaped RBCs (discocytes and echinocytes 1) increased from 47.7% to 67.1%. In LORCCA experiments, rejuvenation did not modify the capacity of RBCs to elongate and induced a reduction in cell volume. In functional tests, rejuvenation increased RBC filterability in a biomimetic splenic filter (+16%) and prevented their adhesion to endothelial cells (-87%).

CONCLUSION

Rejuvenation reduces the proportion of morphologically altered and adhesive RBCs that accumulate during storage. Along with the improvement in their filterability, these data show that rejuvenation improves RBC properties related to their capacity to persist in circulation after transfusion.

Ovine red cell concentrates for transfusion research - is the storage lesion comparable to human red cell concentrates?

BACKGROUND AND OBJECTIVES

Sheep are increasingly being used as a large in vivo animal model of blood transfusion because they provide several advantages over small animals. Understanding the effects of storage duration on ovine (ov) red cell concentrates (RCCs) and how these changes compare with stored human (hu) RCCs is necessary to facilitate clinical translation of research findings.

MATERIALS AND METHODS

OvRCCs (n = 5) collected and processed in standard human blood collection packs, and equivalent huRCCs provided by Australian Red Cross Lifeblood (n = 5), were stored at 2-6°C for 42 days, with samples collected weekly. Haemolysis index was determined by measuring supernatant haemoglobin concentration. Biochemical parameters were evaluated using a blood gas analyser. Energy metabolites and biologically active lipids were measured using commercial assays. Osmotic fragility was determined by lysis in various saline concentrations. Extracellular vesicles were characterized by nanoparticle tracking analysis.

RESULTS

Ovine red blood cells (RBCs) are double in number, smaller in size and more fragile than human RBCs. Haematological values were unchanged throughout storage. In contrast, biochemical and metabolic values, and haemolysis index in three of the five ovRCCs exceeded huRCCs licensing criteria by day 42. Accumulation of extracellular vesicles and biologically active lipids was comparable between huRCCs and ovRCCs.

CONCLUSION

This study documents similarities and differences in the storage lesion of ovRCCs and huRCCs. This new information will guide the design of ovine transfusion models to enhance translation of findings to human transfusion settings.

Hepatic Cytochrome P450 Profiles in Hemorrhagic Shock Model Rats After Transfusion With Stored Red Blood Cells

Red cell transfusions, which deteriorate in quality during storage, triggers several negative biological responses. However, little is known regarding the effects of stored red cell transfusion on cytochrome P450 (P450) profiles. To clarify this issue, we investigated hepatic P450 profiles in hemorrhagic shock model rats after resuscitation with stored packed red cells (PRC). The pharmacokinetics data for P450-metabolizing substrates showed that the clearance of substrates for Cyp1A2 and Cyp3A2 in the stored PRC resuscitation group were decreased compared to sham group. The protein expression, metabolic activity and mRNA expression of the P450 isoforms in the stored PRC resuscitation group were lower than the corresponding values for the sham group. However, these changes would be expected to have weak effects on the in vivo pharmacokinetics of the concomitant drugs based on the criteria stated in the guideline on drug interactions. In contrast, the results of these P450 profiles in the stored PRC and fresh PRC resuscitation group exhibited a similar trend. These results suggest that the stored PRC transfusion has an influence on the hepatic P450 profiles, but is of little clinical significance, not by the deterioration of the quality of red cells but pathophysiological alterations following the hemorrhage and transfusion.

The Effect of Washing of Stored Red Blood Cell Transfusion Units on Post Transfusion Recovery and Outcome in a Pneumosepsis Animal Model

BACKGROUND

Septic patients are often anemic, requiring red blood cell (RBC) transfusions. However, RBC transfusions are associated with organ injury. The mechanisms of RBC-induced organ injury are unknown, but increased clearance of donor RBCs from the circulation with trapping in the organs could play a role. We hypothesized that washing of RBCs prior to transfusion may reduce clearance and trapping of donor cells and thereby reduce organ injury.

METHODS

Sprague-Dawley rats were inoculated intratracheally with 10 colony-forming units (CFU) of Streptococcus pneumoniae or vehicle as a control and transfused with either a washed or standard (non-washed) biotinylated RBC transfusion from syngeneic rats. Controls received saline. Blood samples were taken directly after transfusion and at 24 h to calculate the 24 h post transfusion recovery (PTR). After sacrifice, flow cytometry was used to detect donor RBCs in organs and blood. The organs were histologically scored by a pathologist and CFUs in the lung and blood were counted.

RESULTS

The 24h-PTR was similar between healthy and pneumoseptic rats after a standard transfusion. In healthy rats, a washed transfusion resulted in a higher PTR and less accumulation of donor RBCs in the organs compared with a standard transfusion. However, during pneumonia, this effect of washing was not seen. Transfusion did not further augment lung injury induced by pneumonia, but washing decreased bacterial outgrowth in the lungs associated with reduced lung injury.

CONCLUSION

In healthy recipients, washing increased 24h-PTR of donor RBCs and decreased trapping in organs. In pneumoseptic rats, washing reduced bacterial outgrowth and lung injury, but did not improve PTR.

The Contribution of Storage Medium and Membranes in the Microwave Dielectric Response of Packed Red Blood Cells Suspension

During cold storage, packed red blood cells (PRBCs) undergo slow detrimental changes that are collectively termed storage lesion. The aging of the cells causes alterations in the composition of the storage-medium in the PRBC unit. In this paper, we present the comparison of the dielectric response of water in the primary (fresh) storage medium (citrate phosphate dextrose adenine solution, CPDA-1) versus the storage medium from three expired units of PRBCs. Dielectric response of the water molecules has been characterized by dielectric spectroscopy technique in the microwave frequency band (0.5–40 GHz). The dominant phenomenon is the significant increase of the dielectric strength and decrease the relaxation time τ for the samples of the stored medium in comparison with the fresh medium CPDA-1. Furthermore, we demonstrated that removing the ghosts from PRBC hemolysate did not cause the alteration of the dielectric spectrum of water. Thus, the contribution associated with water located near the cell membrane can be neglected in microwave dielectric measurements.

Ferroportin inhibition attenuates plasma iron, oxidant stress, and renal injury following red blood cell transfusion in guinea pigs

BACKGROUND

Red blood cell (RBC) transfusions result in the sequestration and metabolism of storage-damaged RBCs within the spleen and liver. These events are followed by increased plasma iron concentrations that can contribute to oxidant stress and cellular injury. We hypothesized that administration of a ferroportin inhibitor (FPN-INH) immediately after acute RBC exchange transfusion could attenuate posttransfusion circulatory compartment iron exposure, by retaining iron in spleen and hepatic macrophages.

STUDY DESIGN AND METHODS

Donor guinea pig blood was leukoreduced, and RBCs were preserved at 4°C. Recipient guinea pigs (n = 5/group) were exchange transfused with donor RBCs after refrigerator preservation and dosed intravenously with a small-molecule FPN-INH. Groups included transfusion with vehicle (saline), 5 mg/kg or 25 mg/kg FPN-INH. A time course of RBC morphology, plasma non-transferrin-bound iron (NTBI) and plasma hemoglobin (Hb) were evaluated. End-study spleen, liver, and kidney organ iron levels, as well as renal tissue oxidation and injury, were measured acutely (24-hr after transfusion).

RESULTS

RBC transfusion increased plasma NTBI, with maximal concentrations occurring 8 hours after transfusion. Posttransfusion iron accumulation resulted in tubule oxidation and acute kidney injury. FPN inhibition increased spleen and liver parenchymal/macrophage iron accumulation, but attenuated plasma NTBI, and subsequent renal tissue oxidation/injury.

CONCLUSION

In situations of acute RBC transfusion, minimizing circulatory NTBI exposure by FPN inhibition may attenuate organ-specific adverse consequences of iron exposure.

An animal model of transfusion-related acute lung injury and the role of soluble CD40 ligand

BACKGROUND AND OBJECTIVES

Transfusion-related acute lung injury (TRALI) is a life-threatening complication of transfusion and is one of leading causes of transfusion-associated fatalities. However, the pathogenesis of TRALI is still unclear. Soluble CD40 ligand (sCD40L) is a proinflammatory cytokine that accumulates during blood component storage and is involved in transfusion reactions. The objective of this study was to establish a clinically relevant TRALI animal model and to evaluate the role of sCD40L in TRALI.

MATERIALS AND METHODS

Rats' red-blood-cell (RBC) suspensions were prepared, and the quality of RBC was evaluated. A trauma-haemorrhage-transfusion strategy was applied to build the animal model. Lung oedema was evaluated by histopathology examination, total bronchoalveolar lavage fluid (BALF) protein concentration, Evans blue dye (EBD) leakage and inflammatory cytokines. The sCD40L concentrations were measured.

RESULTS

Storage lesions of RBCs gradually increased over time. Obvious histological evidence of lung injury of rats transfused with a 35-day RBC was observed. The total BALF protein concentration, EBD leakage, inflammatory cytokines concentration were increased significantly in the Day 35 group. The sCD40L concentration increased significantly in the storage RBC suspension over time but was slightly elevated in rat plasma.

CONCLUSIONS

These findings indicated successful establishment of a TRALI animal model with trauma-haemorrhage-transfusion, in which sCD40L may play a minor role in the development of TRALI.

Effects of L-carnitine on the erythrocytes of stored human blood

OBJECTIVES

This study aimed to assess the effects of L-carnitine on oxidative stress in human erythrocytes during storage.

BACKGROUND

Using antioxidants as components of blood storage solutions may combat the effects of storage-induced oxidative stress on erythrocytes.

METHODS

Blood from male adults was stored at 4 °C for 55 days in citrate phosphate dextrose adenine solution, without L-carnitine (Control) and with L-carnitine as an additive (at concentrations of 10, 30 and 60 mM - Experiments). Every fifth day, erythrocyte markers (morphology, count, haemoglobin, haemolysis and osmotic fragility), antioxidant defences (antioxidant enzymes and total antioxidant capacity) and oxidative stress markers (superoxides, lipid peroxidation and protein oxidation products) were analysed.

RESULTS

Oxidative damage was observed in controls (day 25 onwards) and in experiments (day 35 onwards). L-carnitine (10 and 30 mM) protected erythrocytes from damage up to day 35 by maintaining haemoglobin and lipid peroxidation, assisting antioxidant enzymes and increasing antioxidant capacity by elevating sulfhydryls and ascorbic acid. L-carnitine was beneficial in prolonging storage up to 55 days but could not prevent oxidative damage completely in terms of haemolysis and osmotic fragility.

CONCLUSIONS

L-carnitine ameliorated oxidative stress, but combinations with other antioxidants may provide comprehensive protection to erythrocytes during storage.

Extracellular Ubiquitin is the Causal Link between Stored Blood Transfusion Therapy and Tumor Progression in a Melanoma Mouse Model

Background: The transfusion of blood that has been stored for some time was found to be associated with transfusion-related immune modulation (TRIM) responses in cancer patients, which could result in poor clinical outcomes, such as tumor recurrence, metastasis and reduced survival rate. Given the prior observation of the positive correlation between ubiquitin content in whole blood and storage duration by the investigators of the present study, it was hypothesized that this could be the causal link behind the association between the transfusion of stored blood and poor cancer prognosis.

Methods: In the present study, a melanoma mouse model was used to study the potential clinical impact of ubiquitin present in stored blood on cancer prognosis through a variety of cell biology methods, such as flow cytometry and immunohistochemistry.

Results: Both extracellular ubiquitin and the infusion of stored mice blood that comprised of ubiquitin reduced the apoptotic rate of melanoma cells, promoted lung tumor metastasis and tumor progression, and reduced the long-term survival rate of melanoma mice. In addition, the upregulation of tumor markers and tumorigenic TH2 cytokine generation, as well as reduced immune cell numbers, were observed in the presence of ubiquitin.

Conclusions: The present findings provide novel insights into the role of ubiquitin in immune regulation in a melanoma mouse model, and suggest ubiquitin as the causal link between allogeneic blood transfusion therapy and poor cancer prognosis.

Washing or filtering of blood products does not improve outcome in a rat model of trauma and multiple transfusion

BACKGROUND

Transfusion is associated with organ failure and nosocomial infection in trauma patients, which may be mediated by soluble bioactive substances in blood products, including extracellular vesicles (EVs). We hypothesize that removing EVs, by washing or filtering of blood products, reduces organ failure and improves host immune response.

MATERIALS AND METHODS

Blood products were prepared from syngeneic rat blood. EVs were removed from RBCs and platelets by washing. Plasma was filtered through a 0.22‐μm filter. Rats were traumatized by crush injury to the intestines and liver, and a femur was fractured. Rats were hemorrhaged until a mean arterial pressure of 40 mm Hg and randomized to receive resuscitation with standard or washed/filtered blood products, in a 1:1:1 ratio. Sham controls were not resuscitated. Ex vivo whole blood stimulation tests were performed and histopathology was done.

RESULTS

Washing of blood products improved quality metrics compared to standard products. Also, EV levels reduced by 12% to 77%. The coagulation status, as assessed by thromboelastometry, was deranged in both groups and normalized during transfusion, without significant differences. Use of washed/filtered products did not reduce organ failure, as assessed by histopathologic score and biochemical measurements. Immune response ex vivo was decreased following transfusion compared to sham but did not differ between transfusion groups.

CONCLUSION

Filtering or washing of blood products improved biochemical properties and reduced EV counts, while maintaining coagulation abilities. However, in this trauma and transfusion model, the use of optimized blood components did not attenuate organ injury or immune suppression.

Is It Possible to Reverse the Storage-Induced Lesion of Red Blood Cells?

Cold-storage of packed red blood cells (PRBCs) in the blood bank is reportedly associated with alteration in a wide range of RBC features, which change cell storage each on its own timescale. Thus, some of the changes take place at an early stage of storage (during the first 7 days), while others occur later. We still do not have a clear understanding what happens to the damaged PRBC following their transfusion. We know that some portion (from a few to 10%) of transfused cells with a high degree of damage are removed from the bloodstream immediately or in the first hour(s) after the transfusion. The remaining cells partially restore their functionality and remain in the recipient’s blood for a longer time. Thus, the ability of transfused cells to recover is a significant factor in PRBC transfusion effectiveness. In the present review, we discuss publications that examined RBC lesions induced by the cold storage, aiming to offer a better understanding of the time frame in which these lesions occur, with particular emphasis on the question of their reversibility. We argue that transfused RBCs are capable (in a matter of a few hours) of restoring their pre-storage levels of ATP and 2,3-DPG, with subsequent restoration of cell functionality, especially of those properties having a more pronounced ATP-dependence. The extent of reversal is inversely proportional to the extent of damage, and some of the changes cannot be reversed.

The Age of BLood Evaluation (ABLE) randomised controlled trial: description of the UK-funded arm of the international trial, the UK cost-utility analysis and secondary analyses exploring factors associated with health-related quality of life and health-care costs during the 12-month follow-up

BACKGROUND

At present, red blood cells (RBCs) are stored for up to 42 days prior to transfusion. The relative effectiveness and safety of different RBC storage times prior to transfusion is uncertain.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of transfusing fresher RBCs (stored for ≤ 7 days) compared with current standard-aged RBCs in critically ill patients requiring blood transfusions.

DESIGN

The international Age of BLood Evaluation (ABLE) trial was a multicentre, randomised, blinded trial undertaken in Canada, the UK, the Netherlands and France. The UK trial was funded to contribute patients to the international trial and undertake a UK-specific health economic evaluation.

SETTING

Twenty intensive care units (ICUs) in the UK, as part of 64 international centres.

PARTICIPANTS

Critically ill patients aged ≥ 18 years (≥ 16 years in Scotland) expected to require mechanical ventilation for ≥ 48 hours and requiring a first RBC transfusion during the first 7 days in the ICU.

INTERVENTIONS

All decisions to transfuse RBCs were made by clinicians. One patient group received exclusively fresh RBCs stored for ≤ 7 days whenever transfusion was required from randomisation until hospital discharge. The other group received standard-issue RBCs throughout their hospital stay.

MAIN OUTCOME MEASURES

The primary outcome was 90-day mortality. Secondary outcomes included development of organ dysfunction, new thrombosis, infections and transfusion reactions. The primary economic evaluation was a cost-utility analysis.

RESULTS

The international trial took place between March 2009 and October 2014 (UK recruitment took place between January 2012 and October 2014). In total, 1211 patients were assigned to receive fresh blood and 1219 patients to receive standard-aged blood. RBCs were stored for a mean of 6.1 days [standard deviation (SD) ± 4.9 days] in the group allocated to receive fresh blood and 22.0 days (SD ± 8.4 days) in the group allocated to receive standard-aged blood. Patients received a mean of 4.3 RBC units (SD ± 5.2 RBC units) and 4.3 RBC units (SD ± 5.5 RBC units) in the groups receiving fresh blood and standard-aged blood, respectively. At 90 days, 37.0% of patients in the group allocated to receive fresh blood and 35.3% of patients in the group allocated to receive standard-aged blood had died {absolute risk difference 1.7% [95% confidence interval (CI) -2.1% to 5.5%]}. There were no between-group differences in any secondary outcomes. The UK cohort comprised 359 patients randomised and followed up for 12 months for the cost-utility analysis. UK patients had similar characteristics and outcomes to the international cohort. Mean total costs per patient were £32,346 (95% CI £29,306 to £35,385) in the group allocated to receive fresh blood and £33,353 (95% CI £29,729 to £36,978) in the group allocated to receive standard-aged blood. Approximately 85% of the total costs were incurred during the index hospital admission. There were no significant cost differences between the two groups [mean incremental costs for those receiving fresh vs. standard-aged blood: -£231 (95% CI -£4876 to £4415)], nor were there significant differences in outcomes (mean difference in quality-adjusted life-years -0.010, 95% CI -0.078 to 0.057).

LIMITATIONS

Adverse effects from the exclusive use of older RBCs compared with standard or fresh RBCs cannot be excluded.

CONCLUSIONS

The use of RBCs aged ≤ 7 days confers no clinical or economic benefit in critically ill patients compared with standard-aged RBCs.

FUTURE WORK

Future studies should address the safety of RBCs near the end of the current permitted storage age.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN44878718.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 62. See the NIHR Journals Library website for further project information. The international ABLE trial was also supported by peer-reviewed grants from the Canadian Institutes of Health Research (177453), Fonds de Recherche du Québec - Santé (24460), the French Ministry of Health Programme Hospitalier de Recherche Clinique (12.07, 2011) and by funding from Établissement Français du Sang and Sanquin Blood Supply.

Rejuvenation of allogenic red cells: benefits and risks

BACKGROUND AND OBJECTIVES

To review preclinical and clinical studies that have evaluated the effects of red cell rejuvenation in vivo and in vitro and to assess the potential risks and benefits from their clinical use.

MATERIALS AND METHODS

A systematic review and narrative synthesis of the intervention of red cell rejuvenation using a red cell processing solution containing inosine, pyruvate, phosphate and adenine. Outcomes of interest in vitro were changes in red cell characteristics including adenosine triphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG), deformability and the accumulation of oxidized lipids and other reactive species in the red cell supernatant. Outcomes in vivo were 24-h post-transfusion survival and the effects on oxygen delivery, organ function and inflammation in transfused recipients.

RESULTS

The literature search identified 49 studies evaluating rejuvenated red cells. In vitro rejuvenation restored cellular properties including 2,3-DPG and ATP to levels similar to freshly donated red cells. In experimental models, in vivo transfusion of rejuvenated red cells improved oxygen delivery and myocardial, renal and pulmonary function when compared to stored red cells. In humans, in vivo 24-h survival of rejuvenated red cells exceeded 75%. In clinical studies, rejuvenated red cells were found to be safe, with no reported adverse effects. In one adult cardiac surgery trial, transfusion of rejuvenated red cells resulted in improved myocardial performance.

CONCLUSION

Transfusion of rejuvenated red cells reduces organ injury attributable to the red cell storage lesion without adverse effects in experimental studies in vivo. The clinical benefits of this intervention remain uncertain.

Endotoxemia Results in Trapping of Transfused Red Blood Cells in Lungs with Associated Lung Injury

BACKGROUND

Red blood cell (RBC) transfusion is associated with organ failure, in particular in the critically ill. We hypothesized that endotoxemia contributes to increased trapping of RBCs in organs. Furthermore, we hypothesized that this effect is more pronounced following transfusion of stored RBCs compared with fresh RBCs.

METHODS

Adult male Sprague-Dawley rats were randomized to receive injection with lipopolysaccharide from E coli or vehicle and transfusion with fresh or stored biotinylated RBCs. After 24 h, the amount of biotinylated RBCs in organs was measured by flow cytometry, as well as the 24-h post-transfusion recovery. Markers of organ injury and histopathology of organs were assessed.

RESULTS

Endotoxemia resulted in systemic inflammation and organ injury. Following RBC transfusion, donor RBCs were recovered from the lung and kidney of endotoxemic recipients (1.2 [0.8-1.6]% and 2.2 [0.4-4.4]% of donor RBCs respectively), but not from organs of healthy recipients. Trapping of donor RBCs in the lung was associated with increased lung injury, but not with kidney injury. Stored RBCs induced organ injury in the spleen and yielded a lower 24-h post-transfusion recovery, but other effects of storage time were limited.

CONCLUSION

Endotoxemia results in an increased percentage of donor RBCs recovered from the lung and kidney, which is associated with lung injury following transfusion.

In vitro assessment of quality of citrate-phosphate-dextrose-adenine-1 preserved feline blood collected by a commercial closed system

BACKGROUND

Optimal procedure for storage of feline blood is needed. Open-collection systems have been employed in feline medicine, thus limiting the possibility for storage.

OBJECTIVES

To evaluate indicators of quality of feline blood stored for 35 days at +4°C in a closed-collection system specifically designed for cats.

ANIMALS

Eight healthy adult European domestic shorthair cats with a weight of 5-6.8 kg.

METHODS

This is a case series study. A bacteriological test, CBC, blood smear, pH, osmotic fragility, 2,3-diphosphoglycerate (2,3-DPG), and adenosine triphosphate (ATP) measurement were performed weekly on whole blood (WB) units from day 1 to day 35 after donation. The hemolysis index, lactate and potassium concentrations, prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen were measured on plasma aliquots.

RESULTS

One out of eight blood units (BUs) had bacterial growth (Serratia marcescens) at day 35. No significant differences were found regarding CBC, morphology, pH, and osmotic fragility. Despite high inter-individual variability and low starting levels, significant decreases in the mean concentrations of 2,3-DPG (T0 1.99 mmol/g Hb, SD 0.52, T35 1.25 mmol/g Hb, SD 1.43; P = .003) and ATP (T0 1.45 mmol/g Hb, SD 0.71, T35 0.62 mmol/g Hb, SD 0.51; P < .001) were detected during the study, as opposed to an increase in hemolysis (T0 0.11 mmol/L, SD 0.07, T35 0.84 mmol/L, SD 0.19; P < .001), lactate (T0 3.30 mmol/L, SD 0.86, T35 13.36 mmol/L, SD 2.90; P < .001), and potassium (T0 3.10 mmol/L, SD 0.21, T35 4.12 mmol/L, SD 0.35; P < .001) concentrations.

CONCLUSIONS AND CLINICAL IMPORTANCE

The commercial BU kit is appropriate for blood collection and conservation of WB in cats. The maintenance of WB quality indicators during storage is essential for future improvements of feline transfusion medicine.

Blood storage alters mechanical stress responses of erythrocytes

BACKGROUND: Erythrocytes undergo irreversible morphological and biochemical changes during storage. Reduced levels of deformability have been reported for stored erythrocytes. Erythrocyte deformability is essential for healthy microcirculation.

OBJECTIVE: The aim of this study is to evaluate shear stress (SS) induced improvements of erythrocyte deformability in stored blood.

METHODS: Deformability changes were evaluated by applying physiological levels of SS (5 and 10 Pa) in metabolically depleted blood for 48 hours and stored blood for 35 days with citrate phosphate dextrose adenine-1 (CPDA-1). Laser diffractometry was used to measure erythrocyte deformability before and after application of SS.

RESULTS: Erythrocyte deformability, as a response to continuous SS, was significantly improved in metabolically depleted blood, whereas it was significantly impaired in the blood stored for 35 days with CPDA-1 (p≤0.05). The SS-induced improvements of deformability were deteriorated due to storage and relatively impaired according to the storage time. However, deformability of stored blood after exposure to mechanical stress tends to increase at low levels of shear while decreasing at high SS levels.

CONCLUSION: Impairment of erythrocyte deformability after storage may contribute to impairments in the recipient’s microcirculation after blood transfusion. The period of the storage should be considered to prevent microcirculatory problems and insufficient oxygen delivery to the tissues.

Influence of L-Carnitine on Stored Rat Blood: A Study on Plasma

Objective:

Plasma acts as a good indicator of oxidative stress in blood. L-Carnitine is an antioxidant that reduces metabolic stress in cells, thereby providing a protective effect against oxidative stress (OS). L-Carnitine as an additive in storage has not been explored. Thus, this study attempts to analyze the role of L-carnitine in blood storage solution, citrate phosphate dextrose adenine (CPDA)-1, through OS markers including antioxidant enzymes, lipid peroxidation, and protein oxidation.

Materials and Methods:

Blood was collected from male Wistar rats and stored in CPDA-1 solution with L-carnitine (10 mM, 30 mM, and 60 mM: groups LC 10, LC 30, and LC 60, respectively) and without L-carnitine (control group). Plasma was isolated every 5th day and the OS markers were analyzed.

Results:

Superoxide dismutase (SOD) and sulfhydryl (SH) increased over storage in controls, LC 30, and LC 60. Catalase increased in LC 30 and LC 60 during storage. Thiobarbituric acid reactive substances (TBARS) and protein carbonyl (PrC) levels in all groups increased initially and reduced towards the end of storage. SOD and SH levels were maintained while TBARS and PrC levels increased in LC 10.

Conclusion:

L-Carnitine was beneficial in terms of increased antioxidant capacity and SH and decreased lipid peroxidation. This forms the basis for further studies on L-carnitine as a constituent in storage solutions.

A Study of Preoperative Autologous Blood Donation Timing

This study aims to determine the safe and effective autologous blood drawing time for preoperative autologous blood donation (PABDs) by comparing the outcome of two different schedules of PABDs. A total of 144 patients who underwent elective surgery (radical resection of digestive tract tumor, lumbarspinesurgery and Intracranial tumor resection) were retrospectively reviewed. 88 patients had donated autologous blood 2 days before the operation (group 1); 56 patients had donated autologous blood more than 3 days before the operation (group 2). Hb and Hct before the operation and on postoperative days one and three, allogeneic blood transfusions, total bleeding, postoperative length of stay, and length of stay were measured and compared. Hb at postoperative day one was lower in group 2 than in group 1 (P < 0.05). Furthermore, Hb in group 1 was higher at postoperative day one than at postoperative day three (P < 0.05). Differences in postoperative Hct, allogeneic blood transfusions, total bleeding and postoperative length of stay between these two groups were not statistically significant (P > 0.05)., The difference in the average number of postoperative hospitalization days between these two groups was not statistically significant (P > 0.05). The 2 days of PABD did not lead to any adverse recovery effect. It would be helpful to conduct preoperative autologous blood transfusions.

Red Cell Storage Duration Does Not Affect Outcome after Massive Blood Transfusion in Trauma and Nontrauma Patients: A Retrospective Analysis of 305 Patients

Background

Prolonged storage of packed red blood cells (PRBCs) may increase morbidity and mortality, and patients having massive transfusion might be especially susceptible. We therefore tested the hypothesis that prolonged storage increases mortality in patients receiving massive transfusion after trauma or nontrauma surgery. Secondarily, we considered the extent to which storage effects differ for trauma and nontrauma surgery.

Methods

We considered surgical patients given more than 10 units of PRBC within 24 hours and evaluated the relationship between mean PRBC storage duration and in-hospital mortality using multivariable logistic regression. Potential nonlinearities in the relationship were assessed via restricted cubic splines. The secondary hypothesis was evaluated by considering whether there was an interaction between the type of surgery (trauma versus nontrauma) and the effect of storage duration on outcomes.

Results

305 patients were given a total of 8,046 units of PRBCs, with duration ranging from 8 to 36 days (mean ± SD: 22 ± 6 days). The odds ratio [95% confidence interval (CI)] for in-hospital mortality corresponding to a one-day in mean PRBC storage duration was 0.99 (0.95, 1.03, P = 0.77). The relationship did not differ for trauma and nontrauma patients (P = 0.75). Results were similar after adjusting for multiple potential confounders.

Conclusions

Mortality after massive blood transfusion was no worse in patients transfused with PRBC stored for long periods. Trauma and nontrauma patients did not differ in their susceptibility to prolonged PRBC storage.

Biochemical evaluation of the effects of storage on feline erythrocytes

OBJECTIVE

To describe the biochemical changes that occur during storage of feline packed red blood cells.

METHODS

Feline packed red blood cells were obtained from the manufacturer via overnight delivery immediately following collection. Bag spikes were placed using aseptic technique and samples were drawn on days 1, 4, 7, 14, 21, 28 and 35. Sodium, potassium, chloride, glucose, lactate, pH and ammonia were measured at each time point. Aerobic and anaerobic bacterial cultures were submitted following collection on day 35.

RESULTS

There were statistically significant increases in the median concentrations of lactate and ammonia within the first 2 weeks of storage to a concentration of 12·38 mmol/L and 447·96 µmol/L, respectively. Glucose concentrations decreased significantly by day 28 to a mean of 1·86 mmol/L. Median sodium and chloride concentrations increased throughout the course of storage to a concentration of 158·20 and 131·00 mmol/L, respectively. Mean potassium concentrations decreased to a concentration of 2·40 mmol/L.

CLINICAL SIGNIFICANCE

These results show that biochemical derangements within feline packed red blood cells are progressive, with some alterations, such as lactate and ammonia, occurring early within the storage periods, while others, including glucose and electrolytes, are slower to develop. Additional prospective research evaluating the clinical effects of these biochemical alterations is required.

Addition of Sodium Pyruvate to Stored Red Blood Cells Attenuates Liver Injury in a Murine Transfusion Model

RBCs undergo numerous changes during storage and stored RBCs may induce adverse effects, ultimately resulting in organ injury in transfusion recipients. We tested the hypothesis that the addition of SP to stored RBCs would improve the quality of the stored RBCs and mitigate liver injury after transfusion in a murine model. RBCs were harvested from C57BL/6J mice and stored for 14 days in CPDA-1 containing either a solution of SP in saline or saline alone. Haemolysis, the 24-hour posttransfusion recovery, the oxygen-carrying capacity, and the SOD activity of stored RBCs were evaluated. The plasma biochemistry, hepatic MDA level, MPO activity, IL-6, TNF-α concentrations, and histopathology were measured two hours after the transfusion of stored RBCs. Compared with RBCs stored in CPDA-1 and saline, the addition of SP to stored RBCs restored their oxygen-carrying capacity and SOD activity, reduced the AST activity, BUN concentrations, and LDH activity in the plasma, and decreased the MDA level, MPO activity, and concentrations of IL-6 and TNF-α in the liver. These data indicate that the addition of SP to RBCs during storage has a beneficial effect on storage lesions in vitro and subsequently alleviates liver injury after the transfusion of stored RBCs in vivo.

Protocols for massive blood transfusion: when and why, and potential complications

PURPOSE

An update paper on massive bleeding after major trauma. A review of protocols to address massive bleeding, and its possible complications, including coagulation abnormalities, complications related to blood storage, immunosuppression and infection, lung injury associated with transfusion, and hypothermia is carried out.

METHODS

Literature review and discussion with authors' experience.

RESULTS

Massive bleeding is an acute life-threatening complication of major trauma, and consequently its prompt diagnosis and treatment is of overwhelming importance. Treatment requires rapid surgical management together with the massive infusion of colloid and blood.

CONCLUSIONS

Since massive transfusion provokes further problems in patients who are already severely traumatized and anaemic, once this course of action has been decided upon, a profound knowledge of its potential complications, careful monitoring and proper follow-up are all essential. To diagnose this bleeding, most authors favour, as the main first choice tool, a full-body CT scan (head to pelvis), in non-critical severe trauma cases. In addition, focused abdominal sonography for trauma (FAST, an acronym that highlights the necessity of rapid performance) is a very important diagnostic test for abdominal and thoracic bleeding. Furthermore, urgent surgical intervention should be undertaken for patients with significant free intraabdominal fluid and haemodynamic instability. Although the clinical situation and the blood haemoglobin concentration are the key factors considered in this rapid decision-making context, laboratory markers should not be based on a single haematocrit value, as its sensitivity to significant bleeding may be very low. Serum lactate and base deficit are very sensitive markers for detecting and monitoring the extent of bleeding and shock, in conjunction with repeated combined measurements of prothrombin time, activated partial thromboplastin time, fibrinogen and platelets.

Transfusion of Old RBCs Induces Neuroinflammation and Cognitive Impairment

OBJECTIVES

Transfusing RBCs stored for longer than 14 days (old RBC) in humans is common. This transfusion can injure organs, such as lungs and kidneys. We determined whether transfusion with old RBC injured brain.

DESIGN

Prospective, controlled animal study.

SETTING

University research laboratory.

SUBJECTS

Adult male Sprague-Dawley rats.

INTERVENTIONS

Six-month-old Sprague-Dawley rats lost 20% total blood volume and then received RBC prepared from equal volume of the lost blood. RBC was stored for 1 day (fresh RBC) or 7 days (old RBC, storage lesions similar to those of human RBC stored for 28 d). Some rats received IV cell-free hemoglobin. These rats were not subjected to hemorrhage and RBC transfusion.

MEASUREMENTS AND MAIN RESULTS

Rats were subjected to Barnes maze and fear conditioning tests from 1 week after blood transfusion. Rats transfused with old RBC but not fresh RBC took a longer time to identify the target hole in the Barnes maze and had less context-related fear conditioning behavior than control rats. Old RBC significantly increased interleukin 6 and ionized calcium-binding adapter molecule 1 in the hippocampus at 24 hours after the transfusion. These effects were attenuated by sulforaphane and minocycline, an antibiotic with anti-inflammatory property. Old RBC solution had a higher concentration of cell-free hemoglobin. Sulforaphane increased haptoglobin, a chelator of cell-free hemoglobin. Rats that received cell-free hemoglobin had a pattern of neuroinflammation and impairment of learning and memory similar to that of rats that received old RBC.

CONCLUSIONS

These results provide initial evidence to suggest that transfusion of old RBC induces neuroinflammation and impairment of learning and memory. These effects may be mediated by cell-free hemoglobin.

Accelerated clearance of human red blood cells in a rat transfusion model

Background

Animal models are valuable in transfusion research. Use of human red blood cells (RBCs) in animal models facilitates extrapolation of the impact of storage conditions to the human condition but may be hampered by the use of cross species.

Methods

Investigation of clearance and posttransfusion recovery in a rat model using fresh and stored human RBCs.

Results

Directly following transfusion, human RBCs could be detected in the circulation of all recipients, with higher recovery rates for stored RBCs than for fresh RBCs. After 24 h following transfusion, no donor RBCs could be detected in the circulation, but donor RBCs could be detected in all organs of all recipients.

Conclusion

The use of human donor RBCs in a rat transfusion model resulted in clearance from cells from the circulation. Donor cells were found in different organs of the recipients. Rat transfusion models are thus not appropriate to study the efficacy of human RBC transfusion.

Prospects of Vitamin C as an Additive in Plasma of Stored Blood

There is a dire necessity to improve blood storage and prolong shelf-life of blood. Very few studies have focused on oxidative stress (OS) in blood and its influence on plasma with storage. This study attempts to (i) elucidate the continuous changes occurring in plasma during storage through oxidant levels and antioxidant status and (ii) evaluate the influence of vitamin C (VC) as an additive during blood storage. Blood was drawn from male Wistar rats and stored for 25 days at 4°C. Blood samples were divided into control and experimental groups. Plasma was isolated every 5 days and the OS markers, antioxidant enzymes, lipid peroxidation, and protein oxidation products, were studied. Catalase activity increased in all groups with storage. Lipid peroxidation decreased in VC (10) but was maintained in VC (30) and VC (60). Although there were variations in all groups, carbonyls were maintained towards the end of storage. Advanced oxidation protein products (AOPP) increased in VC (30) and were maintained in VC (10) and VC (60). Sulfhydryls were maintained in all groups. Vitamin C could not sufficiently attenuate OS and hence, this opens the possibilities for further studies on vitamin C in combination with other antioxidants, in storage solutions.

Irradiation Can Selectively Kill Tumor Cells while Preserving Erythrocyte Viability in a Co-Culture System

An understanding of how to safely apply intraoperative blood salvage (IBS) in cancer surgery has not yet been obtained. Here, we investigated the optimal dose of ¹³⁷Cs gamma-ray irradiation for killing human hepatocarcinoma (HepG2), gastrocarcinoma (SGC7901), and colonic carcinoma (SW620) tumor cells while preserving co-cultured erythrocytes obtained from 14 healthy adult volunteers. HepG2, SGC7901, or SW620 cells were mixed into the aliquots of erythrocytes. After the mixed cells were treated with ¹³⁷Cs gamma-ray irradiation (30, 50, and 100 Gy), tumor cells and erythrocytes were separated by density gradient centrifugation in Percoll with a density of 1.063 g/ml. The viability, clonogenicity, DNA synthesis, tumorigenicity, and apoptosis of the tumor cells were determined by MTT assay, plate colony formation, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, subcutaneous xenograft implantation into immunocompromised mice, and annexin V/7-AAD staining, respectively. The ATP concentration, 2,3-DPG level, free Hb concentration, osmotic fragility, membrane phosphatidylserine externalization, blood gas variables, reactive oxygen species levels, and superoxide dismutase levels in erythrocytes were analyzed. We found that ¹³⁷Cs gamma-ray irradiation at 50 Gy effectively inhibited the viability, proliferation, and tumorigenicity of HepG2, SGC7901, and SW620 cells without markedly damaging the oxygen-carrying ability or membrane integrity or increasing the oxidative stress of erythrocytes in vitro. These results demonstrated that 50 Gy irradiation in a standard ¹³⁷Cs blood irradiator might be a safe and effective method of inactivating HepG2, SGC7901, and SW620 cells mixed with erythrocytes, which might help to safely allow IBS in cancer surgery.

Transfusion of fresh vs. older red blood cells in the context of infection

The red blood cell (RBC) storage interval has been extended from less than a week to the current storage interval of 6-8 weeks. Regulatory criteria for extending storage rely upon a minimal degree of hemolysis and acceptable in vivo 24-h post transfusion recovery. Clinical studies of safety and efficacy have never been required. Concerns have arisen that RBC toward the end of storage develop a 'storage lesion' with previously unrecognized toxicity. Of the several mechanisms proposed, the bolus of iron delivered to macrophages as a result of hemolysis of stored RBC might pose a particular risk to patients with existing infections. We developed a canine model of pneumonia to compare the toxicity of stored RBC transfusion. We described increased mortality after transfusion of old RBC. We found that transfused older RBC increased mortality, in vivo hemolysis, circulating cell-free hemoglobin that scavenges nitric oxide, and elevations of non-transferrin bound and plasma labile iron. Disappearance of circulating iron correlated with increased mortality, worsening pulmonary function, and bacterial proliferation. Washing decreased the mortality associated with transfusing older RBC, but had the opposite effect on fresher blood. With low doses of bacteria, survival was unaffected by the age of blood, whereas high bacteria doses masked any effect of RBC age on mortality. Older RBC may have adverse effects, but the patient's clinical status, the age, volume and method of preparation of the RBC may be critical variables. Several mechanisms may account for this toxicity, but in the presence of bacterial infection, availability of iron likely plays a major role.

Which is the best schedule of autologous blood storage for preoperative adolescent idiopathic scoliosis patients?

Background

It is critically important for AIS patients to avoid perioperative allogeneic blood transfusions. Toward this aim, many institutes use autologous blood storage to perform perioperative transfusions. However, there is no standard timeline for collecting blood for storage. Therefore, the objective of this prospective cohort study was to compare the outcome of two different schedules for collecting autologous blood before operation in adolescent idiopathic scoliosis (AIS) patients.

Methods

Inclusion criteria are AIS patients, younger than 20 years old, female, operated between 2009 and 2013 with posterior spinal fusion and instrumentation who had 1600 mL autologous blood collected before operation. A total of 61 patients were participated in this study. They were randomly divided into 2 groups based on the storage interval. Weekly group (1W-G) consisted of 30 patients with a total of 1600mL blood collected weekly beginning 4 weeks before the operation. Biweekly group (2W-G) consisted of 31 patients with a total of 1600 mL blood collected biweekly beginning 8 weeks before the operation. The instrumented levels, total bleeding, complications during blood transfusion, and hematological examinations (RBC, Hb, Hct, MCH, MCV, MCHC) were evaluated. A hematological examination was performed before blood collection, before the operation, and on postoperative days 1, 3, and 7. Vasovagal reflex (VVR) was evaluated as complications during blood drawing.

Result

Mean age, height, and weight did not differ significantly between the 2 groups. There were no significant differences in instrumented levels, bleeding during operation, after operation, and collected blood during operation. With the autologous blood, allogeneic blood transfusion was completely avoided. VVR was more frequent in the biweekly group significantly (1W-G 4.2% vs 2W-G 15.3%). In terms of hematological examination, all values showed no significant differences between two groups in the pre-drawing and the pre-operation stage. However, the postoperative Hb and Hct values were higher in the weekly group. Also, MCV and MCHC showed the same behavior with higher values in the weekly group.

Conclusion

A weekly schedule of autologous blood storage is better than a biweekly storage schedule.

Red blood cell storage time and the outcome after coronary surgery

BACKGROUND

The impact of transfusion of aged red blood cells (RBCs) on the outcome after coronary artery bypass grafting (CABG) is controversial. This issue has been investigated in the present study.

MATERIALS AND METHODS

Data on perioperative blood transfusion, storage time of RBCs, and adverse events were available for 819 consecutive patients who underwent isolated CABG and received two to four units of RBCs. The maximum RBC storage time was 35 d.

RESULTS

Repeated-measure test showed that transfusion of all RBC units >14 d and at least one RBC unit >14 d was associated with similar postoperative C-reactive protein (P = 0.245 and P = 0.103, respectively) or creatinine levels (P = 0.414 and P = 0.259, respectively) compared with newer RBC units. Propensity score-adjusted analysis showed similar immediate and late outcome in patients receiving only newer RBCs compared with those who received only older RBCs. Similar findings were observed in patients receiving only newer RBCs compared with patients who received at least one unit of older RBCs. Logistic and proportional hazards analyses adjusted for the number of RBC units showed that the median storage duration of RBCs was not associated with either any of the immediate outcome end points or late mortality.

CONCLUSIONS

These findings suggest that, when the maximum RBC storage time is 35 d, the duration of storage of transfused RBCs does not affect the immediate and late outcome of patients with moderate bleeding after CABG.

Differences in Rat and Human Erythrocytes Following Blood Component Manufacturing: The Effect of Additive Solutions

BACKGROUND

Small animal models have been previously used in transfusion medicine studies to evaluate the safety of blood transfusion products. Although there are multiple studies on the effects of blood banking practices on human red blood cells (RBCs), little is known about the effect of blood component manufacturing on the quality of rat RBCs.

METHODS

Blood from Sprague-Dawley rats and human volunteers (n = 6) was collected in CPD anticoagulant, resuspended in SAGM or AS3, and leukoreduced. In vitro quality was analyzed, including deformability, aggregation, microvesiculation, phosphatidylserine (PS) expression, percent hemolysis, ATP, 2,3-DPG, osmotic fragility, and potassium concentrations.

RESULTS

Compared to human RBCs, rat RBCs had decreased deformability, membrane rigidity, aggregability, and microvesiculation after component manufacturing process. Rat RBCs in SAGM showed higher hemolysis compared to human RBCs in SAGM (rat 4.70 ± 0.83% vs. human 0.34 ± 0.07%; p = 0.002). Rat RBCs in AS3 had greater deformability and rigidity than in SAGM. The number of microparticles/µl and the percentage PS expression were lower in rat RBCs in AS3 than in rat RBCs in SAGM. Hemolysis was also significantly lower in AS3 compared to SAGM (2.21 ± 0.68% vs. 0.87 ± 0.39%; p = 0.028).

CONCLUSION

Rat RBCs significantly differ from human RBCs in metabolic and membrane-related aspects. SAGM, which is commonly used for human RBC banking, causes high hemolysis and is not compatible with rat RBCs.

Construction of d-α-tocopheryl polyethylene glycol succinate/PEO core–shell nanofibers on a blood-contacting surface to reduce the hemolysis of preserved erythrocytes

The TPGS released from the electrospun SEBS protected the preserved red blood cells from oxidative damage, resulting in low hemolysis and mechanical fragility.

Red blood cell storage lesion

OBJECTIVE

To summarize current understanding of the mechanisms responsible for changes occurring during red blood cell (RBC) storage, collectively known as the storage lesion, and to review the biological and clinical consequences of increasing storage time of RBCs.

DATA SOURCES

Human and veterinary clinical studies, experimental animal model studies, and reviews of the RBC storage lesion with no date restrictions.

HUMAN DATA SYNTHESIS

Experimental studies have characterized the evolution of human RBC and supernatant changes that occur during storage and form the basis for concern about the potential for harm from long-term storage of RBCs. Although 4 randomized controlled trials of varying sizes failed to find an association between RBC storage time and negative clinical outcomes, a recent meta-analysis and numerous observational clinical studies have demonstrated that transfusion of old versus fresh stored RBCs is associated with an increased risk of morbidity and mortality, particularly among trauma victims and cardiac surgery patients. Potential clinical consequences of RBC transfusion following development of the storage lesion include risk of organ dysfunction, organ failure, infections, and death.

VETERINARY DATA SYNTHESIS

Experimental animal models have contributed to the evidence supporting adverse consequences of the RBC storage lesion. Studies on relevant RBC storage issues such as the effect of different preservative solutions and leukoreduction have been completed. Transfusion with RBCs stored for 42 days increases mortality in dogs with experimental sepsis.

CONCLUSION

Storage of RBCs induces progressive biochemical, biomechanical, and immunologic changes that affect red cell viability, deformability, oxygen carrying capacity, microcirculatory flow, and recipient response. Most reports in the human and veterinary literature support the concept that there are deleterious effects of the RBC storage lesion, but additional studies with improved experimental design are needed to identify compelling reasons to modify current blood banking and transfusion practices.

Transcutaneous oxygen tension monitoring in critically ill patients receiving packed red blood cells

PURPOSE

Whether transfusions of packed red blood cells (PRBCs) affect tissue oxygenation in stable critically ill patients is still matter of discussion. The microvascular capacity for tissue oxygenation can be determined noninvasively by measuring transcutaneous oxygen tension (tcpO2). The aim of this study was to assess tissue oxygenation by measuring tcpO2 in stable critically ill patients receiving PRBC transfusions.

METHODS

Nineteen stable critically ill patients, who received 2 units of PRBC, were prospectively included into this pilot study. Transcutaneous oxygen tension was measured continuously during PRBC transfusions using Clark's electrodes. In addition, whole blood viscosity and global hemodynamics were determined.

RESULTS

Reliable measurement signals during continuous tcpO2 monitoring were observed in 17 of 19 included patients. Transcutaneous oxygen tension was related to the global oxygen consumption (r=-0.78; P=.003), the arterio-venous oxygen content difference (r=-0.65; P=.005), and the extraction rate (r=-0.71; P=.02). The transfusion-induced increase of the hemoglobin concentration was paralleled by an increase of the whole blood viscosity (P<.001). Microvascular tissue oxygenation by means of tcpO2 was not affected by PRBC transfusions (P=.46). Packed red blood cell transfusions resulted in an increase of global oxygen delivery (P=.02) and central venous oxygen saturation (P=.01), whereas oxygen consumption remained unchanged (P=.72).

CONCLUSIONS

In stable critically ill patients, microvascular tissue oxygenation can be continuously monitored by Clark's tcpO2 electrodes. According to continuous tcpO2 measurements, the microvascular tissue oxygenation is not affected by PRBC transfusions.

Factors Affecting Tissue Oxygenation in Erythrocyte Transfusions

Red blood cell transfusions are used to increase the oxygen-carrying capacity of blood in anemic states. But, because of the changes during storage of blood components and the specifics of preparation, erythrocytes may have controversial effects on tissue oxygenation and microcirculation. Also, the patient situation may play a role in the differing responses in oxygenation and microcirculation. In this review, the studies concerning the effects of banked blood and patient characteristics on microcirculation and tissue oxygenation are summarized.

Storage-induced damage to red blood cell mechanical properties can be only partially reversed by rejuvenation

BACKGROUND

The storage of red blood cells (RBC) is associated with impairment of their properties that can induce a circulatory risk to recipients. In a preceding study (2009), we reported that post-storage rejuvenation (RJ) of stored RBC (St-RBC) efficiently reduced the storage-induced RBC/endothelial cell interaction, while only partially reversing the level of intracellular Ca(2+), reactive oxygen species, and surface phosphatidylserine. In the present study, we examined the RJ effectiveness in repairing St-RBC mechanical properties.

METHODS

RBC, stored in CPDA-1 without pre-storage leukoreduction, were subjected to post-storage RJ, and the deformability, osmotic fragility (OF), and mechanical fragility (MF) of the rejuvenated St-RBC (St-RBCRj) were compared to those of untreated St-RBC and of freshly-collected RBC (F-RBC).

RESULTS

5-week storage considerably increased OF and MF, and reduced the deformability of St-RBC. All alterations were only partially (40-70%) reversed by RJ, depending on the extent of the damage: the greater the damage, the lesser the relative effect of RJ.

CONCLUSION

The findings of the present and preceding studies suggest that different St-RBC properties are differentially reversed by RJ, implying that some of the changes occur during storage and are irreversible.

Does prolonged storage of red blood cells cause harm?

Red blood cells (RBCs) degrade progressively during the weeks of refrigerated storage. No universally accepted definition of 'fresh' or 'old' RBCs exists. While practices vary from country to country, preservative solutions permitting shelf life as long as 7 weeks have been licenced. Transfusion of stored RBCs, particularly those at the end of the approved shelf life, has been implicated in adverse clinical outcomes. The results of observational analyses, animal models and studies in volunteers have proved provocative, controversial and contradictory. A recently completed randomized controlled trial (RCT) in premature infants exemplifies the difficulties with moderately sized clinical studies. Several other RCTs are in progress. The effect of RBC storage may well vary according to the clinical setting. Resolution of the importance of the storage lesion may require large pragmatic clinical trials. In the meantime, institutions involved in blood collection and transfusion should explore strategies that assure blood availability, while limiting the use of the oldest RBCs currently approved by regulation.