Cold-stored platelets for acute bleeding in cardiac surgical patients: a narrative review

PURPOSE

Cold-stored platelets (CSP) are an increasingly active topic of international research. They are maintained at 1-6 °C, in contrast to standard room-temperature platelets (RTP) kept at 20-24 °C. Recent evidence suggests that CSP have superior hemostatic properties compared with RTP. This narrative review explores the application of CSP in adult cardiac surgery, summarizes the preclinical and clinical evidence for their use, and highlights recent research.

SOURCE

A targeted search of MEDLINE and other databases up to 24 February 2022 was conducted. Search terms combined concepts such as cardiac surgery, blood, platelet, and cold-stored. Searches of trial registries ClinicalTrials.gov and WHO International Clinical Trials Registry Platform were included. Articles were included if they described adult surgical patients as their population of interest and an association between CSP and clinical outcomes. References of included articles were hand searched.

PRINCIPAL FINDINGS

When platelets are stored at 1-6 °C, their metabolic rate is slowed, preserving hemostatic function for increased storage duration. Cold-stored platelets have superior adhesion characteristics under physiologic shear conditions, and similar or superior aggregation responses to physiologic agonists. Cold-stored platelets undergo structural, metabolic, and molecular changes which appear to "prime" them for hemostatic activity. While preliminary, clinical evidence supports the conduct of trials comparing CSP with RTP for patients with platelet-related bleeding, such as those undergoing cardiac surgery.

CONCLUSION

Cold-stored platelets may have several advantages over RTP, including increased hemostatic capacity, extended shelf-life, and reduced risk of bacterial contamination. Large clinical trials are needed to establish their potential role in the treatment of acutely bleeding patients.

Irradiating stored blood and storing irradiated blood: Is it different? - A study of serial changes in biochemical parameters of red blood cell units

INTRODUCTION

Gamma Irradiation of blood products accentuates biochemical changes in the blood stored at 4°C. This study tried to compare the changes in potassium, sodium, glucose, lactate, and lactate dehydrogenase (LDH) levels in packed red blood cell (PRBC) units irradiated at various time points and then stored versus those stored for a particular period then irradiated.

METHODOLOGY

One hundred and eighty units of RBCs were randomly assigned equally to be irradiated or not. Eighteen units each were irradiated by gamma irradiator using cobalt 60 (BI 2000) on day 1, 7, 14, 21, and 28 of their storage, respectively, in the irradiation group. All the units were assessed for their plasma levels of potassium, sodium, glucose, LDH, and lactate by clinical chemistry auto analyzer Beckman coulter AU680 weekly. The values were documented and analyzed by SPSS.

RESULTS

Baseline values on day 1 for studied biochemical parameters were comparable between irradiated and nonirradiated groups. Mean values of potassium, lactate and LDH were higher in irradiated than nonirradiated PRBC bags. In contrast, Sodium and Glucose mean values were lower than baseline values. Maximum cumulative mean values were noted in day-21 irradiated bags when the parameters were measured on day-28 for potassium and lactate levels. This was followed by day 14 irradiated bags, followed by day 7 irradiated bags.

CONCLUSION

The study indicates that irradiation of red cells later in their storage period had comparatively more detrimental changes in relation to potassium and lactate than irradiation in earlier days. Consideration of irradiation to be performed as close to the issue as possible to reduce a lesser number of days of storage postirradiation is to be explored.

The platelet proteasome and immunoproteasome are stable in buffy-coat derived platelet concentrates for up to 7 days

OBJECTIVES

Characterization of the proteasome and its stability in buffy-coat derived platelet concentrates (PCs) during storage.

BACKGROUND

The proteasome plays a key role in cell homeostasis by processing misfolded or abnormal proteins and regulating the levels and activities of a high number of proteins contributing to cell cycle, survival, and proliferation. Controversial data exist, whether inhibition of the proteasome affects platelet function. Little is known about function, expression, and stability of the proteasome in PCs during storage, and the potential role of the platelet proteasome in storage lesions.

STUDY DESIGN AND METHODS

PCs were produced by the buffy-coat method in additive solution and stored at room temperature under agitation. Platelet aggregation was monitored by light transmission aggregometry. Proteasome complexes were assessed by immunoprecipitation and immunoblotting, and proteasome activity was measured using fluorogenic substrates specific for the three different proteolytic activities over 7 days of storage.

RESULTS

Proteasome inhibition led to a decreased platelet aggregation response after activation with collagen, ADP, TRAP-6, and thrombin. There were no changes in the expression of the catalytic active subunits as well as the proteasome activity during storage of PCs, comparing baseline and day 7.

DISCUSSION

Platelet proteasome function is relevant for platelet aggregation in response to various agonists. The constitutive and stable expression of the active standard- and immunoproteasome in platelets makes it unlikely that loss of proteasome function is a relevant cause of storage lesions.

GSTP1 rs1695 and rs1871042, and SOD2 rs4880 as molecular markers of lipid peroxidation in blood storage

BACKGROUND

Red blood cells (RBC) are subject to oxidative stress by reactive oxygen species (ROS) during storage. Molecular characterisation of oxidative stress in stored RBC, which may also occur in other blood components during long periods of storage, is rare.

MATERIALS AND METHODS

Our study included 45 healthy RBC donors recruited in Brazil. Blood was collected into standard Grifols® Triple Bags containing CPD SAG-M. Haematological values, biochemical data, and oxidative stress markers were assessed weekly during storage until 42 days after collection. GSTM1 and GSTT1 were determined by multiplex-polymerase chain reaction (PCR), while GSTP1 rs1695 and rs1871042, CAT rs1001179, and SOD2 rs4880 were evaluated by real-time PCR.

RESULTS

A direct proportional relationship was found between storage time and levels of ROS and thiobarbituric acid reactive substances (TBARS, indicators of lipid peroxidation) (p<0.001). These parameters were indirectly proportional to ABTS values (p<0.001). The plasma concentration of TBARS was associated with GSTP1 303AG/GG, GSTP1 -16CT/TT, and SOD2 47CT/TT genotypes. Single-nucleotide polymorphisms at the CAT C-262T gene were not associated with TBARS, nor were oxidative markers of ROS.

DISCUSSION

Prolonged storage may result in the onset of erythrocyte deterioration. Our results clearly indicate that erythrocytes are capable of attenuating ROS for 2 weeks of storage. We observed an association between elevated TBARS levels and the presence of GSTP1 and SOD2 variants in stored RBC. Although notable for heterozygous variants, this association was even stronger for the homozygous variants GSTP1 rs1695 (303GG), GSTP1 rs1871042 (-16TT), and SOD2 rs4880 (47TT). These findings accentuate the importance of genetic factors in storage lesions and will expand our understanding and consideration of endogenous and exogenous causes in improving clinical treatment with blood transfusions.

Effect of Leukoreduction on Hematobiochemical Parameters and Storage Hemolysis in Canine Whole Blood Units

Simple Summary

During the storage of blood units, cells undergo many changes, defined as storage lesions; these are biochemical, morphological and immunological modifications and seem to be responsible for adverse post-transfusion effects in recipients. The pre-storage leukoreduction seems to reduce them. The aims of this study are both to evaluate the human filter effectiveness and the effect of pre-storage leukoreduction in stored canine whole blood units. We tested whole blood units, leukoreduced and not, obtained from seven enrolled subjects, until the 42nd day. The white blood cell (WBC) and platelet (PLT) counts are reported to express the leukoreduction effectiveness. As indicators of storage-induced hemolysis, the lactate dehydrogenase activity (LDH) and sodium, potassium, and chlorine electrolytes were measured in plasma, and the red blood cell (RBC) count, hemoglobin concentration (Hgb), and hematocrit (Hct) were obtained with the complete blood count (CBC). The mean corpuscular volume (MCV) values and morphological index obtained from blood smear evaluation were used as indices of morphological changes. We observed that the leukoreduction filter for human use is equally effective on canine whole blood and that leukoreduction has a partially protective role to prevent some storage lesions.

Abstract

Storage lesions (SLs) occur when the red blood cell quality is altered during the preservation of blood units. Pre-storage leukoreduction would limit the number of SLs. The aims of this study were to evaluate the effectiveness of a leukoreduction filter for human use and the effect of pre-storage leukoreduction on some ematobiochemical parameters in stored canine whole blood. Seven canine blood units were tested. Each one was divided into two units—one leukoreduced (LRWB) and one non-leukoreduced (nLRWB). On each unit, we determined the complete blood count (CBC), lactate-dehydrogenase (LDH), electrolytes (Na⁺, K⁺, Cl⁻), morphological index (MI) and hemolysis, on storage days 0, 7, 14, 21, 28, 35, and 42. Leukoreduction allowed a 98.30% recovery of the RBC count, retaining 99.69% and 94.91% of WBCs and PLTs, respectively. We detected a significant increase of LDH and MI with strongly higher values in nLRWB compared to LRWB. A progressive increase in electrolytes and LDH concentrations was observed as indices of stored hemolysis. LDH showed significantly lower values in LRWB units compared to nLRWB, suggesting its release from leukocytes. In the majority of units, hemolysis reached 1% on the 42nd day of storage. We assert the human leukoreduction filter effectiveness on canine whole blood, and we recommend using nLRWB before day 14, especially for critically ill patients. The difference of the basal hemolysis (day 0) percentages observed between subjects suggests that more studies should be performed to confirm a possible inter-individual donor biological variability of RBC membrane resistance, as happens in humans.

Effects of leukoreduction on storage lesions in whole blood and blood components of dogs

Background

Leukoreduction is a routine procedure in human transfusion medicine but is uncommon in veterinary.

Objectives

To evaluate the effect of leukoreduction on the quality of canine whole blood (WB) and blood products during storage.

Animals

Ten canine blood donors.

Methods

This is a case series study. An amount of 450 mL of blood was collected from each dog. Five WB and 5 packed red blood cells (pRBC) bags were divided into 2 units each: leukoreduced (LR) and non‐leukoreduced (nLR). RBC count, erythrocytes' mean osmotic fragility (MOF), 2,3‐diphosphoglycerate (2,3‐DPG), adenosine triphosphate (ATP), percentage of hemolysis, potassium (K), lactate, glucose, and cytokines were measured weekly from day of donation (T0) to day 35 (T35); pH, coagulation times, and clotting factors were evaluated at T0 and T35 from WB and in fresh frozen plasma after 1 year of storage.

Results

Leukoreduction showed positive effects on lactate (T35: LR WB 14.42 mmol/L SD 2.71, nLR WB 22.42 mmol/L SD 1.86, LR pRBC 20.88 mmol/L SD 2.65, nLR pRBC 36.81 mmol/L SD 2.34; P < .0001), pH (T35: LR WB 6.88 SD 0.16, nLR WB 6.69 SD 0.20, P = .02; LR pRBC 6.57 SD 0.23, nLR pRBC 6.22 SD 0.11; P < .001), and K (LR pRBC 4.08 mmol/L SD 0.88, nLR pRBC 5.48 mmol/L SD 0.90; P < .001). Increasing values of IL8 were observed in nLR units during storage (T0: 4167 ± 11 888 pg/mL; T35: 6367 ± 11 612 pg/mL).

Conclusion and Clinical Importance

LR blood units are recommended to critically ill dogs with marked inflammatory conditions.

Hemoglobin Oxidation in Stored Blood Accelerates Hemolysis and Oxidative Injury to Red Blood Cells

Introduction  Maintaining blood supply is a challenge in blood banks. Red blood cells (RBCs) stored at 4°C experience issues of biochemical changes due to metabolism of cells, leading to changes collectively referred to as “storage lesions.” Oxidation of the red cell membrane, leading to lysis, contributes to these storage lesions.

Methods  Blood bags with CPD-SAGM stored at 4°C for 28 days were withdrawn aseptically on days 1, 14, and 28. Hematology analyzer was used to investigate RBC indices. Hemoglobin oxidation was studied through spectrophotometric scan of spectral change. RBC lysis was studied with the help of Drabkin's assay, and morphological changes were observed by light and scan electron microscopy.

Results  RBCs show progressive changes in morphology echinocytes and spherocytes on day 28. There was 0.85% RBC lysis, an approximately 20% decrease in percentage oxyhemoglobin, and a 14% increase in methemoglobin formation, which shows hemoglobin oxidation on day 28.

Conclusions  Oxidative damage to RBC, with an increase in storage time was observed in the present study. The observed morphological changes to RBC during the course of increased time shows that there is progressive damage to RBC membrane and a decrease in hemoglobin concentration; percentage RBC lysis is probably due to free hemoglobin and iron.

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

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

Hypoxic storage of erythrocytes slows down storage lesions and prolongs shelf-life

Conventional storage conditions of erythrocytes cause storage lesions. We propose that hypoxic storage conditions, involving removal of oxygen and replacement with helium, the changes in stored erythrocytes under hypoxic condition were observed and assessed. Erythrocytes were divided into two equal parts, then stored in conventional and hypoxic conditions, separately. Blood gas analysis, hemorheology, and hemolysis were performed once a week. Energy metabolism and membrane damage were monitored by enzyme-linked immunosorbent assay. Phosphatidylserine exposure was measured by flow cytometry. P₅₀ was measured and the oxygen dissociation curve (ODC) plotted accordingly. Erythrocyte morphology was observed microscopically. In the 9th week of storage, the hemolysis of the hypoxia group was 0.7%; lower (p < .05) than that of the control group and still below the threshold of quality requirements. The dissolved oxygen and pO₂ were only 1/4 of that in the control group (p < .01); the adenosine triphosphate, glucose, and lactic acid levels were decreased (p < .05), while the 2,3-diphosphoglycerate levels were increased relative to that in the control group (p < .01). There were no statistically significant differences in membrane damage, deformability, and aggregation between the two groups. In addition, the ODC of the two groups was shifted to the left but this difference was not statistically different. Basically similar to the effect of completely anaerobic conditions. Erythrocytes stored under hypoxic conditions could maintain a relatively stable state with a significant decrease in hemolysis, reduction of storage lesions, and an increase in shelf-life.

Estimation of free hemoglobin concentrations in blood bags by diffuse reflectance spectroscopy

Free hemoglobin (FHB) concentration is considered a prospect quality indicator for erythrocyte suspensions (ES) under storage. Storage lesions alter the optical properties of ES and can be monitored by diffuse reflectance spectroscopy. Due to storage lesions, erythrocytes lyse and release hemoglobin into the extracellular medium. The purpose of the study is to model and assess the quality of ES units in a blood bank with diffuse reflectance measurements together with hematological variables reflecting absorption and scattering characteristics of ES. FHB concentrations were modeled based on the increased scattering in the extracellular medium. A semiempirical model was used for relating optical properties of ES to the diffuse reflectance measurements. The attenuation in the blood bag was computed and its influence was discarded via normalization, in accordance with Monte Carlo simulations. In the experiments, 40 ES units were measured multiple times during prolonged storage of 70 days. A generalized linear model was used for modeling the training set, and, in the validation, the highest correlation coefficient between predicted and actual FHB concentrations was 0.89. Predicting the actual value was accurate at a maximum level of R2  =  0.80. The error rate of the model in diagnosing the true quality was about 10%.

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

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

Rat red blood cell storage lesions in various additive solutions

BACKGROUND

Small rodent models are routinely used to evaluate the safety and efficacy of blood transfusions. Limited comprehensive literature exists about effect of different storage solutions in rat red blood cells (RBCs) characteristics. RBCs undergo time dependent biochemical and biophysical changes during storage known as hypothermic storage lesions (HSLs).

OBJECTIVE

This study evaluates the effects of RBC additive solutions (AS) during storage of rat RBCs.

METHODS

Blood was leukoreduced and stored as per manufacturer instructions at 4°C up to 42-days. Three solutions, CPDA-1; AS-1; and AS-7 (SOLX), were evaluated. Biochemical parameters measured included extracellular K+, pH, hemolysis, 2,3-diphosphoglycerate (2,3-DPG), oxygen affinity, ATP, and lactate. Mechanical properties measured included RBC deformability, elongation index (EI), RBC membrane shear elastic modulus (SEM), mean corpuscular volume (MCV), viscosity, and aggregability.

RESULTS

There were no differences in biochemical or mechanical parameters at baseline or after one week of storage. However, after two weeks, AS-7 preserved biochemical and mechanical properties as compared to CPDA-1 and AS-1. Changes were observed to be significant after 14-days of storage. AS-7 prevented extracellular K+ increase, reduced acidosis, showed lower hemolysis, preserved ATP and 2,3-DPG levels (consequently oxygen affinity), and reduced lactate. AS-7, when compared to CPDA-1 and AS-1, prevented the reduction in RBC deformability and was found to preserve the EI at multiple shear stresses, the membrane SEM, the aggregability and viscosity.

DISCUSSION

Rat RBCs stored with AS-7 presented reduced changes in biochemical and mechanical parameters, when compared with rat RBCs stored in CPDA-1 and AS-1, after as early as two weeks of storage.

Blood Quality Diagnostic Device Detects Storage Differences Between Donors

In 2013, nearly 15 million units of banked blood were transfused in the United States of America alone. Blood shortages are expected to increase globally. Donated blood is not equal due to differences in quality and deterioration rate. There are no methods to detect time-dependent biochemical and biophysical changes of red blood cells (RBCs) or the deterioration rate of donated RBCs. Nine randomly selected RBC units collected by the San Diego Blood Bank were examined for interdonor variability over six weeks of storage. In vitro RBC quality was assessed weekly by conventional biochemical tests including free Hb, K+, ATP, P50, 2,3 DPG, lactate, and pH. Deformability was measured via cell filtration. Briefly, the RBC suspension (10% Hct), was forced through a 5.0-μm pore membrane (106 mm²) at various flow rates. No interdonor variability in biochemical or mechanical parameters was observed at baseline. Interdonor variability in biochemical properties (free Hb, K+, ATP, P50, 2,3 DPG, lactate, and pH) was observed after 14 days of storage. However, significant differences from baseline in RBC mechanical properties (i.e., filterability) were observed as early as 7 days into storage at the lowest flow rates and after 28 days of storage at all flow rates. There was a net decrease in filterability over time for all donors, but the rate at which filterability decreased (i.e., deterioration rates) was different when comparing individual donors. Changes in all biochemical parameters were significant different between donors. These data suggest that filterability is more sensitive to changes in blood quality than conventional biochemical parameters.

Characteristics of resveratrol and serotonin on antioxidant capacity and susceptibility to oxidation of red blood cells in stored human blood in a time-dependent manner

Objective

In stored red blood cells (RBCs), which are used in diseases (e.g., acute blood loss and leukaemia), storage lesions arise by oxidative stress and other factors over time. This study investigated the protective effects of resveratrol and serotonin on stored RBCs.

Methods

Blood from each donor (n = 10) was placed in different bags containing 70 mL of citrate phosphate dextrose (total volume: 500 mL) and divided into three groups (n = 30): control, 60 µg/mL resveratrol, and 60 µg/mL serotonin. Malondialdehyde (MDA) and glutathione (GSH) levels, activity of glutathione peroxidase (GSH-Px), catalase, and carbonic anhydrase (CA), and susceptibility to oxidation in RBCs, and pH in whole blood were measured at baseline and on days 7, 14, 21, and 28.

Results

MDA levels and susceptibility to oxidation were increased in all three groups time-dependently, but this increase was greater in the serotonin group than in the other groups. Activity of GSH-Px, CAT, and CA, as well as GSH levels, were decreased in the control and serotonin groups time-dependently, but were significantly preserved in the resveratrol group. The pH was decreased in all groups time-dependently.

Conclusion

Our study shows that resveratrol attenuates susceptibility to oxidation of RBCs and protects their antioxidant capacity, and partially preserves CA activity time-dependently.

Effect of blood bank storage on the rheological properties of male and female donor red blood cells

It was previously demonstrated that red blood cell (RBC) deformability progressively decreases during storage along with other changes in RBC mechanical properties. Recently, we reported that the magnitude of changes in RBC mechanical fragility associated with blood bank storage in a variety of additive solutions was strongly dependent on the donor gender [15]. Yet, the potential dependence of changes in the deformability and relaxation time of stored blood bank RBCs on donor gender is not known. The objective of this study was to determine the effects of donor gender and blood bank storage on RBC deformability and relaxation time through the measurement of RBC suspension viscoelasticity. Packed RBC units preserved in AS-5 solution from 12 male and 12 female donors (three from each ABO group) were obtained from the local blood center and tested at 1, 4 and 7 weeks of storage at 1-6°C. At each time point, samples were aseptically removed from RBC units and hematocrit was adjusted to 40% before assessment of cell suspension viscoelasticity. RBC suspensions from both genders demonstrated progressive increases (p < 0.05) in viscosity, elasticity and relaxation time at equivalent shear rates over seven weeks of storage indicating a decrease in RBC deformability. No statistically significant differences in RBC deformability or relaxation time were observed between male and female RBCs at any storage time. The decrease in RBC deformability during blood bank storage may reduce tissue perfusion and RBC lifespan in patients receiving blood bank RBCs.

Quality and safety of red blood cells stored in two additive solutions subjected to multiple room temperature exposures

BACKGROUND AND OBJECTIVES

Many international standards state that red blood cell (RBC) products should be discarded if left out of controlled temperature storage for longer than 30 min to reduce the risk of bacterial growth and RBC loss of viability. This study aimed to verify whether repeated short-time exposures to room temperature (RT) influence RBCs quality and bacterial proliferation.

MATERIALS AND METHODS

Saline-adenine-glucose-mannitol (SAGM) and AS-3 RBC units were split and exposed to RT for 30 or 60 min on day 2, 7, 14, 21, and 42 of storage while reference units remained stored at 1-6°C. Red blood cell in vitro quality parameters were evaluated after each exposure. In a second experiment, SAGM and AS-3 RBC units were split and inoculated with Staphylococcus epidermidis (5 CFU/ml), Serratia marcescens (1 CFU/ml), and Serratia liquefaciens (1 CFU/ml). Reference units remained in storage while test units were exposed as described previously. Bacterial concentrations were investigated after each exposure.

RESULTS

No differences were noticed between reference and test units in any of the in vitro parameters investigated. S. epidermidis did not grow in either reference or exposed RBCs. While S. marcescens did not grow in AS-3, bacterial growth was observed in RT-exposed SAGM RBCs on day 42. Similar growth was obtained for S. liquefaciens in the two additive solutions for both reference and test units.

CONCLUSION

Short-time exposures to RT do not affect RBC quality and do not significantly influence bacterial growth. An expansion of the '30-minute' rule to 60 min should be considered by regulatory agencies.

Oxidative injury as contributory factor for red cells storage lesion during twenty eight days of storage

BACKGROUND

Storage of red blood cells at 4 °C is associated with deleterious metabolic and biochemical changes, collectively referred to as "storage lesions". Lipid peroxidation of the red cell membrane leading to lysis contributes to these storage lesions. The aim of the present study was to investigate oxidative injury to red cells during storage for 28 days and its correlation with markers of red cell membrane damage.

MATERIALS AND METHODS

Samples from 30 units of red blood cells stored at 4 °C for 28 days were withdrawn aseptically on day 0, day 14 and day 28 of storage. Markers of membrane damage including plasma haemoglobin, plasma potassium and lactate dehydrogenase (LDH) concentrations and markers of oxidative injury such as malondialdehyde (MDA) levels, haemoglobin oxidation and osmotic fragility were studied in all samples.

RESULTS

Statistically significant (p<0.001) increases in the mean values of plasma haemoglobin, plasma potassium, LDH and markers of oxidative injury such as MDA and haemoglobin oxidation were observed over the storage period of 28 days. Direct correlations of MDA and haemoglobin oxidation with membrane damage, as reflected by plasma haemoglobin concentration, were observed.

CONCLUSION

Oxidative injury to red blood cells during storage leads to membrane damage and lysis. The role of antioxidants in the prevention of this deleterious effect of storage warrants investigation.