Alterations of red blood cell metabolome during cold liquid storage of erythrocyte concentrates in CPD-SAGM

Blood storage effect of G6PD on RBC quality

BACKGROUND

The most prevalent metabolic condition of red blood cells, glucose-6-phosphate dehydrogenase (G6PD) deficiency, affects around 35 million people globally. The highest prevalence is seen in tropical and subtropical areas of the eastern hemisphere, where it can affect up to 35 % of the population. G6PD deficiency, the most prevalent enzyme deficit, is not currently tested for in blood products. G6PD deficiency is a genetic factor that influences the quality of stored red blood cells impacting their ability to respond to oxidative stress. This hospital-based cross-sectional study aimed at assessing the prevalence of G6PD deficiency in donor blood and the impact of the enzyme deficiency on red cell indices during storage.

METHOD

A total of 57 blood bags were screened for G6PD deficiency. Red cell indices and blood film comments were investigated on Day 0, Day 7 and Day 14 of storage.

RESULTS

Eight out of 57 (14 %) had the G6PD full defect and 86 % (49/57) had no defect. Over the course of 14 days storage, the hemoglobin and red blood cell count significantly decreased in G6PD-deficient blood units with a corresponding significant increase in mean corpuscular volume and red cell distribution width-standard deviation compared to baseline and normal G6PD activity. The blood film comment showed 85.7 % normocytic normochromic, 2.0 % microcytic hypochromic and 12.2 % macrocytic hyperchromic from G6PD-non-deficient donors whereas G6PD-deficient donors had 75 % normocytic normochromic with 12.5 % microcytic hypochromic and 12.5 % macrocytic hypochromic after 2 wk in storage.

CONCLUSION

Red blood cell count and hemoglobin reduce significantly in G6PD-deficient donor units during storage with an associated increased mean corpuscular volume indicating progressive loss of the cellular membrane homeostatic mechanism that could potentially result in further hemolysis during long term storage.

Red blood cell metabolism: a window on systems health towards clinical metabolomics

PURPOSE OF REVIEW

This review focuses on recent advances in the understanding of red blood cell (RBC) metabolism as a function of hypoxia and oxidant stress. In particular, we will focus on RBC metabolic alterations during storage in the blood bank, a medically relevant model of erythrocyte responses to energy and redox stress.

RECENT FINDINGS

Recent studies on over 13 000 healthy blood donors, as part of the Recipient Epidemiology and Donor Evaluation Study (REDS) III and IV-P RBC omics, and 525 diversity outbred mice have highlighted the impact on RBC metabolism of biological factors (age, BMI), genetics (sex, polymorphisms) and exposure (dietary, professional or recreational habits, drugs that are not grounds for blood donor deferral).

SUMMARY

We review RBC metabolism from basic biochemistry to storage biology, briefly discussing the impact of inborn errors of metabolism and genetic factors on RBC metabolism, as a window on systems metabolic health. Expanding on the concept of clinical chemistry towards clinical metabolomics, monitoring metabolism at scale in large populations (e.g., millions of blood donors) may thus provide insights into population health as a complementary tool to genetic screening and standard clinical measurements.

Cold storage surpasses the impact of biological age and donor characteristics on red blood cell morphology classified by deep machine learning

Assessment of the morphology of red blood cells (RBCs) can improve clinical benefits following blood transfusion. Deep machine learning surpasses traditional microscopy-based classification methods, offering more accurate and consistent results while reducing time and labor intensity. RBCs from teenage males, teenage females, senior males, and senior females were biologically age-profiled or density-separated into dense/old RBCs (O-RBCs) and less-dense/young (Y-RBCs) throughout hypothermic storage and assessed using image flow cytometry with deep machine learning analysis. Regardless of biological age, morphology index decreased with hypothermic storage. Significant differences in RBC morphology index were not seen when comparing unseparated RBCs (U-RBCs), O-RBCs, and Y-RBCs, although the proportions of morphology subclasses revealed differences between RBCs groups from different donor groups and in samples with different biological age. Cold storage remains the most significant influence on morphology, although teenage male donors demonstrated slightly more susceptibility to storage lesions compared with senior males and females. Our work highlights that hypothermic storage most significantly impacts RBC morphology over biological age and donor characteristics, emphasizing the importance of storage effects on transfusion quality and safety.

Development of an easy non-destructive particle isolation protocol for quality control of red blood cell concentrates

The extracellular vesicle release in red blood cell concentrates reflects progressive accumulation of storage lesions and could represent a new measure to be implemented routinely in blood centres in addition to haemolysis. Nevertheless, there is currently no standardized isolation protocol. In a previous publication, we developed a reproducible ultracentrifugation-based protocol (20,000 × g protocol) that allows to classify red blood cell concentrates into three cohorts according to their vesiculation level. Since this protocol was not adapted to meet routine requirements, the goal of this study was to develop an easier method based on low-speed centrifugation (2,000 × g protocol) and limited red blood cell concentrate volumes to match with a non-destructive sampling from the quality control sampling tubing. Despite the presence of contaminants, mainly in the form of albumin and lipoproteins, the material isolated with the 2,000 × g protocol contained red blood cell-derived vesicular structures. It was reproducible, could predict the number of extracellular vesicles obtained with the 20,000 × g protocol and better discriminated between the three vesiculation cohorts than haemolysis at the legal expiry date of 6 weeks. However, by decreasing red blood cell concentrate volumes to fit with the volume in the quality control tubing, particle yield was highly reduced. Therefore, centrifugation time and relative centrifugal force were adapted (1,000 × g protocol), allowing for the recovery of a similar particle number and composition between small and large volumes sampled from the main unit, in different vesiculation cohorts over time. A similar observation was made with the 1,000 × g protocol between small volumes sampled from the quality control tubing and the mother-bag. In conclusion, our study paves the way for the use of the 2,000 × g protocol (adapted to a 1,000 × g protocol with the quality control sampling tubing) for particle measurement in blood centres.

It's in your blood: The impact of age, sex, genetic factors and exposures on stored red blood cell metabolism

Transfusion of packed red blood cell (RBCs) saves millions of lives yearly worldwide, making packed RBCs the most commonly administered drug in hospitals after vaccines. However, not all blood units are created equal. By examining blood products as they age in blood banks, transfusion scientists are gaining insights into the intricacies of human chemical individuality as regulated by biological factors (such as sex, age, and body mass index), genetic and non-genetic factors like environmental, dietary, and other exposures. Here, we review recent literature on this topic, with an emphasis on studies linking genetic traits to the metabolic heterogeneity of blood products, the hemolytic propensity of stored RBCs, and transfusion outcomes in both healthy autologous and non-autologous patients requiring transfusion. Given the role of RBCs as a simplified model of eukaryotic cells, and RBC storage as a medically relevant application modeling erythrocyte responses to oxidant stress, these insights have the potential not only to guide the development of precision transfusion strategies, but also to identify novel mechanisms of RBC metabolic regulation relevant to responses to hypoxia and oxidant stress in human (patho)physiology.

Attenuation of Oxidative Stress in Erythrocytes Stored with Vitamin C and l-Carnitine in Additive Solution-7

Background: Blood transfusion has advanced toward component therapy for specific requirements during trauma and surgery. Oxidative stress is induced in erythrocytes during storage. Hence, antioxidants as additives can be employed to counteract oxidative stress and enhance antioxidant defenses. Therefore, this study investigates the combinatorial effects of vitamin C and l-carnitine on erythrocytes during storage. Methodology: Erythrocyte samples were categorized into control and experimental groups-vitamin C (10 mM) and l-carnitine (10 mM) and stored under blood bank conditions (at 4°C) for 35 days. Hemoglobin (Hb), antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GPX]), lipid peroxidation products (conjugate dienes and thiobarbituric acid reactive substances [TBARSs]), protein oxidation products, metabolic markers (glucose, lactate dehydrogenase), glutathione (GSH), superoxides, and hemolysis were assessed at weekly intervals. Results: SOD activity increased on day 7 in the controls, whereas it increased on days 7 and 14 in the experimental groups. CAT activity increased on day 35 in both the groups. GPX activity increased on day 7 in the controls. Hb levels decreased on days 14 and 35 in the controls and on day 35 in the experimental groups. Hemolysis increased from day 7 onward in both the groups. Protein oxidation products were maintained throughout the storage. GSH levels increased on day 21 in the controls and on days 14 and 21 in the experimental groups. Superoxides and conjugate dienes decreased from day 14 in both the groups. TBARSs decreased on day 7 in the experimental groups. Conclusion: Vitamin C and l-carnitine have synergistically enhanced the efficacy of stored erythrocytes in terms of Hb, antioxidant enzymes, and lipid peroxidation.

Proteostasis and metabolic dysfunction in a distinct subset of storage-induced senescent erythrocytes targeted for clearance

Although refrigerated storage slows the metabolism of volunteer donor RBCs, cellular aging still occurs throughout this in vitro process, which is essential in transfusion medicine. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and which are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSE high ) and morphologically-normal RBCs (CFSE low ), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSE high RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSE high RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSE high RBC membranes. CFSE high RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen ex vivo perfusion. Conversely, molecular, cellular, and circulatory properties of long-stored CFSE low RBCs resembled those of short-stored RBCs. CFSE high RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in SMEs, targeting these senescent cells for clearance.

Impact of Different Red Blood Cell Storage Solutions and Conditions on Cell Function and Viability: A Systematic Review

Red blood cell (RBC) storage solutions have evolved significantly over the past decades to optimize the preservation of cell viability and functionality during hypothermic storage. This comprehensive review provides an in-depth analysis of the effects of various storage solutions and conditions on critical RBC parameters during refrigerated preservation. A wide range of solutions, from basic formulations such as phosphate-buffered saline (PBS), to advanced additive solutions (ASs), like AS-7 and phosphate, adenine, glucose, guanosine, saline, and mannitol (PAGGSM), are systematically compared in terms of their ability to maintain key indicators of RBC integrity, including adenosine triphosphate (ATP) levels, morphology, and hemolysis. Optimal RBC storage requires a delicate balance of pH buffering, metabolic support, oxidative damage prevention, and osmotic regulation. While the latest alkaline solutions enable up to 8 weeks of storage, some degree of metabolic and morphological deterioration remains inevitable. The impacts of critical storage conditions, such as the holding temperature, oxygenation, anticoagulants, irradiation, and processing methods, on the accumulation of storage lesions are also thoroughly investigated. Personalized RBC storage solutions, tailored to individual donor characteristics, represent a promising avenue for minimizing storage lesions and enhancing transfusion outcomes. Further research integrating omics profiling with customized preservation media is necessary to maximize post-transfusion RBC survival and functions. The continued optimization of RBC storage practices will not only enhance transfusion efficacy but also enable blood banking to better meet evolving clinical needs.

Effect of leukoreduction on the omics phenotypes of canine packed red blood cells during refrigerated storage

BACKGROUND

Red blood cell (RBC) storage promotes biochemical and morphological alterations, collectively referred to as storage lesions (SLs). Studies in humans have identified leukoreduction (LR) as a critical processing step that mitigates SLs. To date no study has evaluated the impact of LR on metabolic SLs in canine blood units using omics technologies.

OBJECTIVE

Compare the lipid and metabolic profiles of canine packed RBC (pRBC) units as a function of LR in fresh and stored refrigerated (up to 42 days) units.

ANIMALS

Packed RBC units were obtained from 8 donor dogs enrolled at 2 different Italian veterinary blood banks.

STUDY DESIGN AND METHODS

Observational study. A volume of 450 mL of whole blood was collected using Citrate-Phosphate-Dextrose-Saline-Adenine-Glucose-Mannitol (CPD-SAGM) transfusion bags with a LR filter to produce 2 pRBC units for each donor, without (nLR-pRBC) and with (LR-pRBC) LR. Units were stored in the blood bank at 4 ± 2°C. Sterile weekly samples were obtained from each unit for omics analyses.

RESULTS

A significant effect of LR on fresh and stored RBC metabolic phenotypes was observed. The nLR-pRBC were characterized by higher concentrations of free short and medium-chain fatty acids, carboxylic acids (pyruvate, lactate), and amino acids (arginine, cystine). The LR-pRBC had higher concentrations of glycolytic metabolites, high energy phosphate compounds (adenosine triphosphate [ATP]), and antioxidant metabolites (pentose phosphate, total glutathione).

CONCLUSION AND CLINICAL IMPORTANCE

Leukoreduction decreases the metabolic SLs of canine pRBC by preserving energy metabolism and preventing oxidative lesions.

Erythrocyte metabolism

Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.

Age-Markers on the Red Blood Cell Surface and Erythrocyte Microparticles may Constitute a Multi-parametric Strategy for Detection of Autologous Blood Transfusion

BACKGROUND

Autologous blood transfusion is one of the illicit strategies, banned by the World Anti-Doping Agency, to increase the levels of hemoglobin, with a consequent improvement in the delivery of oxygen to tissues. At present, this practice is detectable exclusively by the individual, longitudinal monitoring of hematological biomarkers, as in the hematological module of the Athlete Biological Passport; but this indirect approach may suffer from different confounding factors. We are presenting a multi-parametric, analytical strategy to detect autologous blood transfusions by targeting the modification of the red blood cells during storage. We focused on the assessment of "storage lesions", targeting (i) membrane proteins: Glycophorin-A and Band 3 complex, (ii) biomarkers of oxidative stress: Peroxiredoxin-2, (iii) biomarkers of senescence: CD47 and Phosphatidylserine, (iv) erythrocytes microparticles.

RESULTS

All of the above markers were monitored, by immunological and flow cytofluorimetric methods, on samples of stored whole blood collected at different time intervals, and on fresh blood samples, collected for official doping control tests, mixed "ex vivo" to simulate an autotransfusion. Although anonymized before the delivery to the laboratory, it was possible to mix samples belonging to the same subject based on the "athlete biological passport" code. Our results showed that the irreversible alteration of RBCs morphology, the loss of membrane integrity, the occurrence of hemolysis phenomena, and, more in general, the "aging" of the erythrocytes during storage are closely related to: (i) the reduced concentration, on the erythrocyte membrane, of Band 3 protein (decrease of 19% and of 39% after 20 and 40 days of storage respectively) and of glycophorin A (- 47% and - 63% respectively); (ii) the externalization of phosphatidyl serine (with a five-fold increase after 20 days and a further 2× increase after 40 days); (iii) the reduced concentration of CD47; and (iv) increased levels of erythrocyte microparticles.

CONCLUSIONS

The most promising method to detect the presence of transfused blood in whole blood samples can be based on a multi-parametric strategy, considering jointly both protein expression on RBCs membranes and micro-vesiculation phenomena.

Mitapivat reprograms the RBC metabolome and improves anemia in a mouse model of hereditary spherocytosis

Hereditary spherocytosis (HS) is the most common, nonimmune, hereditary, chronic hemolytic anemia after hemoglobinopathies. The genetic defects in membrane function causing HS lead to perturbation of the RBC metabolome, with altered glycolysis. In mice genetically lacking protein 4.2 (4.2-/-; Epb42), a murine model of HS, we showed increased expression of pyruvate kinase (PK) isoforms in whole and fractioned RBCs in conjunction with abnormalities in the glycolytic pathway and in the glutathione (GSH) system. Mitapivat, a PK activator, metabolically reprogrammed 4.2-/- mouse RBCs with amelioration of glycolysis and the GSH cycle. This resulted in improved osmotic fragility, reduced phosphatidylserine positivity, amelioration of RBC cation content, reduction of Na/K/Cl cotransport and Na/H-exchange overactivation, and decrease in erythroid vesicles release in vitro. Mitapivat treatment significantly decreased erythrophagocytosis and beneficially affected iron homeostasis. In mild-to-moderate HS, the beneficial effect of splenectomy is still controversial. Here, we showed that splenectomy improves anemia in 4.2-/- mice and that mitapivat is noninferior to splenectomy. An additional benefit of mitapivat treatment was lower expression of markers of inflammatory vasculopathy in 4.2-/- mice with or without splenectomy, indicating a multisystemic action of mitapivat. These findings support the notion that mitapivat treatment should be considered for symptomatic HS.

Tyrosine phosphorylation of band 3 impairs the storage quality of suspended red blood cells in the Tibetan high-altitude polycythemia population

Due to environmental hypoxia on the Tibetan Plateau, local residents often exhibit a compensative increase in hemoglobin concentration to maintain the body's oxygen supply. However, increases in hemoglobin and hematocrit (Hct) pose a serious challenge to the quality of stored suspended red blood cells (SRBCs) prepared from the blood of high-hemoglobin populations, especially populations at high altitude with polycythemia in Tibet. To explore the difference in storage quality of SRBCs prepared from plateau residents with a high hemoglobin concentration, blood donors were recruited from Tibet (> 3600 m) and Chengdu (≈ 500 m) and divided into a high-altitude control (HAC) group, high-altitude polycythemia (HAPC) group and lowland control (LLC) group according to their hemoglobin concentration and altitude of residence. The extracellular acidification rate (ECAR), pyruvate kinase (PK) activity and band 3 tyrosine phosphorylation were analyzed on the day of blood collection. Then, whole-blood samples were processed into SRBCs, and storage quality parameters were analyzed aseptically on days 1, 14, 21 and 35 of storage. Overall, we found that tyrosine 21 phosphorylation activated glycolysis by releasing glycolytic enzymes from the cytosolic domain of band 3, thus increasing glucose consumption and lactate accumulation during storage, in the HAPC group. In addition, band 3 tyrosine phosphorylation impaired erythrocyte deformability, accompanied by the highest hemolysis rate in the HAPC group, during storage. We believe that these results will stimulate new ideas to further optimize current additive solutions for the high-hemoglobin population in Tibet and reveal new therapeutic targets for the treatment of HAPC populations.

Early Perturbations in Red Blood Cells in Response to Murine Malarial Parasite Infection: Proof-of-Concept 1H NMR Metabolomic Study

BACKGROUND

The major focus of metabolomics research has been confined to the readily available biofluids-urine and blood serum. However, red blood cells (RBCs) are also readily available, and may be a source of a wealth of information on vertebrates. However, the comprehensive metabolomic characterization of RBCs is minimal although they exhibit perturbations in various physiological states. RBCs act as the host of malarial parasites during the symptomatic stage. Thus, understanding the changes in RBC metabolism during infection is crucial for a better understanding of disease progression.

METHODS

The metabolome of normal RBCs obtained from Swiss mice was investigated using 1H NMR spectroscopy. Several 1 and 2-dimensional 1H NMR experiments were employed for this purpose. The information from this study was used to investigate the changes in the RBC metabolome during the early stage of infection (~1% infected RBCs) by Plasmodium bergheii ANKA.

RESULTS

We identified over 40 metabolites in RBCs. Several of these metabolites were quantitated using 1H NMR spectroscopy. The results indicate changes in the choline/membrane components and other metabolites during the early stage of malaria.

CONCLUSIONS

The paper reports the comprehensive characterization of the metabolome of mouse RBCs. Changes during the early stage of malarial infection suggest significant metabolic alteration, even at low parasite content (~1%).

GENERAL SIGNIFICANCE

This study should be of use in maximizing the amount of information available from metabolomic experiments on the cellular components of blood. The technique can be directly applied to real-time investigation of infectious diseases that target RBCs.

Red Blood Cell Metabolism In Vivo and In Vitro

Red blood cells (RBC) are the most abundant cell in the human body, with a central role in oxygen transport and its delivery to tissues. However, omics technologies recently revealed the unanticipated complexity of the RBC proteome and metabolome, paving the way for a reinterpretation of the mechanisms by which RBC metabolism regulates systems biology beyond oxygen transport. The new data and analytical tools also informed the dissection of the changes that RBCs undergo during refrigerated storage under blood bank conditions, a logistic necessity that makes >100 million units available for life-saving transfusions every year worldwide. In this narrative review, we summarize the last decade of advances in the field of RBC metabolism in vivo and in the blood bank in vitro, a narrative largely influenced by the authors' own journeys in this field. We hope that this review will stimulate further research in this interesting and medically important area or, at least, serve as a testament to our fascination with this simple, yet complex, cell.

Variability of extracellular vesicle release during storage of red blood cell concentrates is associated with differential membrane alterations, including loss of cholesterol-enriched domains

Transfusion of red blood cell concentrates is the most common medical procedure to treat anaemia. However, their storage is associated with development of storage lesions, including the release of extracellular vesicles. These vesicles affect in vivo viability and functionality of transfused red blood cells and appear responsible for adverse post-transfusional complications. However, the biogenesis and release mechanisms are not fully understood. We here addressed this issue by comparing the kinetics and extents of extracellular vesicle release as well as red blood cell metabolic, oxidative and membrane alterations upon storage in 38 concentrates. We showed that extracellular vesicle abundance increased exponentially during storage. The 38 concentrates contained on average 7 × 1012 extracellular vesicles at 6 weeks (w) but displayed a ∼40-fold variability. These concentrates were subsequently classified into 3 cohorts based on their vesiculation rate. The variability in extracellular vesicle release was not associated with a differential red blood cell ATP content or with increased oxidative stress (in the form of reactive oxygen species, methaemoglobin and band3 integrity) but rather with red blood cell membrane modifications, i.e., cytoskeleton membrane occupancy, lateral heterogeneity in lipid domains and transversal asymmetry. Indeed, no changes were noticed in the low vesiculation group until 6w while the medium and the high vesiculation groups exhibited a decrease in spectrin membrane occupancy between 3 and 6w and an increase of sphingomyelin-enriched domain abundance from 5w and of phosphatidylserine surface exposure from 8w. Moreover, each vesiculation group showed a decrease of cholesterol-enriched domains associated with a cholesterol content increase in extracellular vesicles but at different storage time points. This observation suggested that cholesterol-enriched domains could represent a starting point for vesiculation. Altogether, our data reveal for the first time that the differential extent of extracellular vesicle release in red blood cell concentrates did not simply result from preparation method, storage conditions or technical issues but was linked to membrane alterations.

Oxidants and Antioxidants in the Redox Biochemistry of Human Red Blood Cells

Red blood cells (RBCs) are exposed to both external and internal sources of oxidants that challenge their integrity and compromise their physiological function and supply of oxygen to tissues. Autoxidation of oxyhemoglobin is the main source of endogenous RBC oxidant production, yielding superoxide radical and then hydrogen peroxide. In addition, potent oxidants from other blood cells and the surrounding endothelium can reach the RBCs. Abundant and efficient enzymatic systems and low molecular weight antioxidants prevent most of the damage to the RBCs and also position the RBCs as a sink of vascular oxidants that allow the body to maintain a healthy circulatory system. Among the antioxidant enzymes, the thiol-dependent peroxidase peroxiredoxin 2, highly abundant in RBCs, is essential to keep the redox balance. A great part of the RBC antioxidant activity is supported by an active glucose metabolism that provides reducing power in the form of NADPH via the pentose phosphate pathway. There are several RBC defects and situations that generate oxidative stress conditions where the defense mechanisms are overwhelmed, and these include glucose-6-phosphate dehydrogenase deficiencies (favism), hemoglobinopathies like sickle cell disease and thalassemia, as well as packed RBCs for transfusion that suffer from storage lesions. These oxidative stress-associated pathologies of the RBCs underline the relevance of redox balance in these anucleated cells that lack a mechanism of DNA-inducible antioxidant response and rely on a complex and robust network of antioxidant systems.

The relationship between glycosylated hemoglobin level and red blood cell storage lesion in blood donors

BACKGROUND

Glycosylated hemoglobin (HbA1c), not routinely screened in blood donors, is associated with morphological, biochemical, and functional abnormalities of red blood cells (RBCs) and with enhanced oxidative stress. We aimed to explore HbA1c levels in blood donors and their effect on RBC storage.

STUDY DESIGN AND METHODS

An analytical cross-sectional study was conducted on 875 eligible blood donors aged 18-60 years from May 1, 2021, to August 30, 2021. Two selected groups of donors (HbA1c <6.5%, n = 10; HbA1c ≥ 6.5%, n = 10) exhibiting as similar as possible baseline values (such as age, sex, and living habits, etc.) were recruited for blood donation in leukoreduced CPDA-1 units. RBC morphological, biochemical, structural, and oxidative stress states were measured during 5-35 days of storage.

RESULTS

Elevated HbA1c prevalence was 37%, including 31.7% (277/875) in the prediabetes range (HbA1c 5.7%-6.4%) and 5.4% (47/875) in the diabetes range (HbA1c ≥ 6.5%). Age, body mass index (BMI), smoking, and alcohol consumption were the main factors influencing the HbA1c levels. During storage, high-HbA1c group had abnormal RBC morphology, impaired membrane function, and ion imbalance (higher mean corpuscular volume, distribution width, hemolysis rate, potassium ion efflux, and phosphatidylserine exposure) as compared with low HbA1c group. Additionally, RBC oxidative stress was significantly increased in donors with high HbA1c levels during 21-35 days.

DISCUSSION

Blood donors proportion with abnormal HbA1c levels was relatively high, and donor HbA1c levels may be associated with stored RBCs capacity. Our study provides new insights into the different effects of donor HbA1c levels on RBC storage lesions.

Red Blood Cell Extracellular Vesicle-Based Drug Delivery: Challenges and Opportunities

Recently, red blood cell-derived extracellular vesicles (RBCEVs) have attracted attention for clinical applications because of their safety and biocompatibility. RBCEVs can escape macrophages through the binding of CD47 to inhibitory receptor signal regulatory protein α. Furthermore, genetic materials such as siRNA, miRNA, mRNA, or single-stranded RNA can be encapsulated within RBCEVs and then released into target cells for precise treatment. However, their side effects, half-lives, target cell specificity, and limited large-scale production under good manufacturing practice remain challenging. In this review, we summarized the biogenesis and composition of RBCEVs, discussed the advantages and disadvantages of RBCEVs for drug delivery compared with synthetic nanovesicles and non-red blood cell-derived EVs, and provided perspectives for overcoming current limitations to the use of RBCEVs for clinical applications.

Storage Duration and Red Blood Cell-Derived Microparticles in Packed Red Blood Cells Obtained from Donors with Thalassemia

OBJECTIVE

To address the effects of storage duration on red blood cell (RBC)-derived microparticles (RMPs) in packed RBCs from donors who have thalassemia.

MATERIALS AND METHODS

Packed RBCs were prepared according to laboratory routine. The quantity of RMPs was determined using FACSCalibur and counting beads.

RESULTS

Across durations of storage, the packed RBCs from donors with thalassemia (n = 28) and healthy volunteers (n = 104) showed average RMPs to be 47,426 (10,139‒127,785) particles/μL vs 49,021 (13,033‒126,749) particles/μL, respectively (P = .63). The peak RMP levels in donors with thalassemia and healthy volunteers, respectively, were shown in products from storage days 34 and 38. Both groups showed a trend toward a positive association between RMP concentration and the duration of storage in packed RBC bags stored under blood bank conditions.

CONCLUSION

Our results suggest that storage-induced RMP release has similar effects in stored packed RBCs obtained from both donors with thalassemia and healthy volunteers.

Ionotropic receptors mediate nitrogenous waste avoidance in Drosophila melanogaster

Ammonia and its amine-containing derivatives are widely found in natural decomposition byproducts. Here, we conducted biased chemoreceptor screening to investigate the mechanisms by which different concentrations of ammonium salt, urea, and putrescine in rotten fruits affect feeding and oviposition behavior. We identified three ionotropic receptors, including the two broadly required IR25a and IR76b receptors, as well as the narrowly tuned IR51b receptor. These three IRs were fundamental in eliciting avoidance against nitrogenous waste products, which is mediated by bitter-sensing gustatory receptor neurons (GRNs). The aversion of nitrogenous wastes was evaluated by the cellular requirement by expressing Kir2.1 and behavioral recoveries of the mutants in bitter-sensing GRNs. Furthermore, by conducting electrophysiology assays, we confirmed that ammonia compounds are aversive in taste as they directly activated bitter-sensing GRNs. Therefore, our findings provide insights into the ecological roles of IRs as a means to detect and avoid toxic nitrogenous waste products in nature.

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.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Fatty acid desaturase activity in mature red blood cells and implications for blood storage quality

BACKGROUND

Increases in the red blood cell (RBC) degree of fatty acid desaturation are reported in response to exercise, aging, or diseases associated with systemic oxidant stress. However, no studies have focused on the presence and activity of fatty acid desaturases (FADS) in the mature RBC.

STUDY DESIGN AND METHODS

Steady state metabolomics and isotope-labeled tracing experiments, immunofluorescence approaches, and pharmacological interventions were used to determine the degree of fatty acid unsaturation, FADS activity as a function of storage, oxidant stress, and G6PD deficiency in human and mouse RBCs.

RESULTS

In 250 blood units from the REDS III RBC Omics recalled donor population, we report a storage-dependent accumulation of free mono-, poly-(PUFAs), and highly unsaturated fatty acids (HUFAs), which occur at a faster rate than saturated fatty acid accumulation. Through a combination of immunofluorescence, pharmacological inhibition, tracing experiments with stable isotope-labeled fatty acids, and oxidant challenge with hydrogen peroxide, we demonstrate the presence and redox-sensitive activity of FADS2, FADS1, and FADS5 in the mature RBC. Increases in PUFAs and HUFAs in human and mouse RBCs correlate negatively with storage hemolysis and positively with posttransfusion recovery. Inhibition of these enzymes decreases accumulation of free PUFAs and HUFAs in stored RBCs, concomitant to increases in pyruvate/lactate ratios. Alterations of this ratio in G6PD deficient patients or units supplemented with pyruvate-rich rejuvenation solutions corresponded to decreased PUFA and HUFA accumulation.

CONCLUSION

Fatty acid desaturases are present and active in mature RBCs. Their activity is sensitive to oxidant stress, storage duration, and alterations of the pyruvate/lactate ratio.

Quantifying dynamic range in red blood cell energetics: Evidence of progressive energy failure during storage

BACKGROUND

During storage, red blood cells (RBCs) undergo significant biochemical and morphologic changes, referred to collectively as the "storage lesion". It was hypothesized that these defects may arise from disrupted oxygen-based regulation of RBC energy metabolism, with resultant depowering of intrinsic antioxidant systems.

STUDY DESIGN AND METHODS

As a function of storage duration, the dynamic range in RBC metabolic response to three models of biochemical oxidant stress (methylene blue, hypoxanthine/xanthine oxidase, and diamide) was assessed, comparing glycolytic flux by NMR and UHPLC-MS methodologies. Blood was processed/stored under standard conditions (AS-1 additive solution) with leukoreduction. Over a 6-week period, RBC metabolic and antioxidant status were assessed at baseline and following exposure to the three biochemical oxidant models. Comparison was made of glycolytic flux (¹ H-NMR tracking of [2-¹³ C]-glucose and metabolomic phenotyping with [1,2,3-¹³ C₃ ] glucose), reducing equivalent (NADPH/NADP⁺ ) recycling, and thiol-based (GSH/GSSG) antioxidant status.

RESULTS

As a function of storage duration, we observed the following: (1) a reduction in baseline hexose monophosphate pathway (HMP) flux, the sole pathway responsible for the regeneration of the essential reducing equivalent NADPH; with (2) diminished stress-based dynamic range in both overall glycolytic as well as proportional HMP flux. In addition, progressive with storage duration, RBCs showed (3) constraint in reducing equivalent (NADPH) recycling capacity, (4) loss of thiol based (GSH) recycling capacity, and (5) dysregulation of metabolon assembly at the cytoplasmic domain of Band 3 membrane protein (cdB3).

CONCLUSION

Blood storage disturbs normal RBC metabolic control, depowering antioxidant capacity and enhancing vulnerability to oxidative injury.

Assessment of transient changes in oxygen diffusion of single red blood cells using a microfluidic analytical platform

Red blood cells (RBCs) capability to deliver oxygen (O₂) has been routinely measured by P50. Although this defines the ability of RBCs to carry O₂ under equilibrium states, it cannot determine the efficacy of O₂ delivery in dynamic blood flow. Here, we developed a microfluidic analytical platform (MAP) that isolates single RBCs for assessing transient changes in their O₂ release rate. We found that in vivo (biological) and in vitro (blood storage) aging of RBC could lead to an increase in the O₂ release rate, despite a decrease in P50. Rejuvenation of stored RBCs (Day 42), though increased the P50, failed to restore the O₂ release rate to basal level (Day 0). The temporal dimension provided at the single-cell level by MAP could shed new insights into the dynamics of O₂ delivery in both physiological and pathological conditions.

Donor-dependent aging of young and old red blood cell subpopulations: Metabolic and functional heterogeneity

BACKGROUND

Characteristics of red blood cells (RBCs) are influenced by donor variability. This study assessed quality and metabolomic variables of RBC subpopulations of varied biologic age in red blood cell concentrates (RCCs) from male and female donors to evaluate their contribution to the storage lesion.

STUDY DESIGN AND METHODS

Red blood cell concentrates from healthy male (n = 6) and female (n = 4) donors were Percoll separated into less dense ("young", Y-RCCs) and dense ("old", O-RCCs) subpopulations, which were assessed weekly for 28 days for changes in hemolysis, mean cell volume (MCV), hemoglobin concentration (MCHC), hemoglobin autofluorescence (HGB), morphology index (MI), oxygen affinity (p50), rigidity, intracellular reactive oxygen species (ROS), calcium ([Ca²⁺ ]), and mass spectrometry-based metabolomics.

RESULTS

Young RCCs having disc-to-discoid morphology showed higher MCV and MI, but lower MCHC, HGB, and rigidity than O-RCCs, having discoid-to-spheroid shape. By Day 14, Y-RCCs retained lower hemolysis and rigidity and higher p50 compared to O-RCCs. Donor sex analyses indicated that females had higher MCV, HGB, ROS, and [Ca²⁺ ] and lower hemolysis than male RBCs, in addition to having a decreased rate of change in hemolysis by Day 28. Metabolic profiling indicated a significant sex-related signature across all groups with increased markers of high membrane lipid remodeling and antioxidant capacity in Y-RCCs, whereas O-RCCs had increased markers of oxidative stress and decreased coping capability.

CONCLUSION

The structural, functional, and metabolic dissimilarities of Y-RCCs and O-RCCs from female and male donors demonstrate RCC heterogeneity, where RBCs from females contribute less to the storage lesion and age slower than males.

Restoration of Physiological Levels of Uric Acid and Ascorbic Acid Reroutes the Metabolism of Stored Red Blood Cells

After blood donation, the red blood cells (RBCs) for transfusion are generally isolated by centrifugation and then filtrated and supplemented with additive solution. The consecutive changes of the extracellular environment participate to the occurrence of storage lesions. In this study, the hypothesis is that restoring physiological levels of uric and ascorbic acids (major plasmatic antioxidants) might correct metabolism defects and protect RBCs from the very beginning of the storage period, to maintain their quality. Leukoreduced CPD-SAGM RBC concentrates were supplemented with 416 µM uric acid and 114 µM ascorbic acid and stored during six weeks at 4 °C. Different markers, i.e., haematological parameters, metabolism, sensitivity to oxidative stress, morphology and haemolysis were analyzed. Quantitative metabolomic analysis of targeted intracellular metabolites demonstrated a direct modification of several metabolite levels following antioxidant supplementation. No significant differences were observed for the other markers. In conclusion, the results obtained show that uric and ascorbic acids supplementation partially prevented the metabolic shift triggered by plasma depletion that occurs during the RBC concentrate preparation. The treatment directly and indirectly sustains the antioxidant protective system of the stored RBCs.

Nicotine exposure increases markers of oxidant stress in stored red blood cells from healthy donor volunteers

BACKGROUND

Cigarette smoking is a frequent habit across blood donors (approx. 13% of the donor population), that could compound biologic factors and exacerbate oxidant stress to stored red blood cells (RBCs).

STUDY DESIGN AND METHODS

As part of the REDS-III RBC-Omics (Recipient Epidemiology Donor Evaluation Study III Red Blood Cell-Omics) study, a total of 599 samples were sterilely drawn from RBC units stored under blood bank conditions at Storage Days 10, 23, and 42 days, before testing for hemolysis parameters and metabolomics. Quantitative measurements of nicotine and its metabolites cotinine and cotinine oxide were performed against deuterium-labeled internal standards.

RESULTS

Donors whose blood cotinine levels exceeded 10 ng/mL (14% of the tested donors) were characterized by higher levels of early glycolytic intermediates, pentose phosphate pathway metabolites, and pyruvate-to-lactate ratios, all markers of increased basal oxidant stress. Consistently, increased glutathionylation of oxidized triose sugars and lipid aldehydes was observed in RBCs donated by nicotine-exposed donors, which were also characterized by increased fatty acid desaturation, purine salvage, and methionine oxidation and consumption via pathways involved in oxidative stress-triggered protein damage-repair mechanisms.

CONCLUSION

RBCs from donors with high levels of nicotine exposure are characterized by increases in basal oxidant stress and decreases in osmotic hemolysis. These findings indicate the need for future clinical studies aimed at addressing the impact of smoking and other sources of nicotine (e.g., nicotine patches, snuff, vaping, secondhand tobacco smoke) on RBC storage quality and transfusion efficacy.

Ethyl glucuronide, a marker of alcohol consumption, correlates with metabolic markers of oxidant stress but not with hemolysis in stored red blood cells from healthy blood donors

BACKGROUND

Red blood cell (RBC) storage in the blood bank is associated with the progressive accumulation of oxidant stress. While the mature erythrocyte is well equipped to cope with such stress, recreative habits like alcohol consumption may further exacerbate the basal level of oxidant stress and contribute to the progress of the storage lesion.

STUDY DESIGN AND METHODS

RBC levels of ethyl glucuronide, a marker of alcohol consumption, were measured via ultra-high-pressure liquid chromatography coupled with high-resolution mass spectrometry. Analyses were performed on 599 samples from the recalled donor population at Storage Days 10, 23, and 42 (n = 250), as part of the REDS-III RBC-Omics (Recipient Epidemiology Donor Evaluation Study III Red Blood Cell-Omics) study. This cohort consisted of the 5th and 95th percentile of donors with extreme hemolytic propensity out of the original cohort of 13,403 subjects enrolled in the REDS-III RBC Omics study. Ehtyl glucuronide levels were thus correlated to global metabolomics and lipidomics analyses and RBC hemolytic propensity.

RESULTS

Ethyl glucuronide levels were positively associated with oxidant stress markers, including glutathione consumption and turnover, methionine oxidation, S-adenosylhomocysteine accumulation, purine oxidation, and transamination markers. Decreases in glycolysis and energy metabolism, the pentose phosphate pathway and ascorbate system were observed in those subjects with the highest levels of ethyl glucuronide, though hemolysis values were comparable between groups.

CONCLUSION

Though preliminary, this study is suggestive that markers of alcohol consumption are associated with increases in oxidant stress and decreases in energy metabolism with no significant impact on hemolytic parameters in stored RBCs from healthy donor volunteers.

Donor glucose-6-phosphate dehydrogenase deficiency decreases blood quality for transfusion

BACKGROUNDGlucose-6-phosphate dehydrogenase (G6PD) deficiency decreases the ability of red blood cells (RBCs) to withstand oxidative stress. Refrigerated storage of RBCs induces oxidative stress. We hypothesized that G6PD-deficient donor RBCs would have inferior storage quality for transfusion as compared with G6PD-normal RBCs.METHODSMale volunteers were screened for G6PD deficiency; 27 control and 10 G6PD-deficient volunteers each donated 1 RBC unit. After 42 days of refrigerated storage, autologous 51-chromium 24-hour posttransfusion RBC recovery (PTR) studies were performed. Metabolomics analyses of these RBC units were also performed.RESULTSThe mean 24-hour PTR for G6PD-deficient subjects was 78.5% ± 8.4% (mean ± SD), which was significantly lower than that for G6PD-normal RBCs (85.3% ± 3.2%; P = 0.0009). None of the G6PD-normal volunteers (0/27) and 3 G6PD-deficient volunteers (3/10) had PTR results below 75%, a key FDA acceptability criterion for stored donor RBCs. As expected, fresh G6PD-deficient RBCs demonstrated defects in the oxidative phase of the pentose phosphate pathway. During refrigerated storage, G6PD-deficient RBCs demonstrated increased glycolysis, impaired glutathione homeostasis, and increased purine oxidation, as compared with G6PD-normal RBCs. In addition, there were significant correlations between PTR and specific metabolites in these pathways.CONCLUSIONBased on current FDA criteria, RBCs from G6PD-deficient donors would not meet the requirements for storage quality. Metabolomics assessment identified markers of PTR and G6PD deficiency (e.g., pyruvate/lactate ratios), along with potential compensatory pathways that could be leveraged to ameliorate the metabolic needs of G6PD-deficient RBCs.TRIAL REGISTRATIONClinicalTrials.gov NCT04081272.FUNDINGThe Harold Amos Medical Faculty Development Program, Robert Wood Johnson Foundation grant 71590, the National Blood Foundation, NIH grant UL1 TR000040, the Webb-Waring Early Career Award 2017 by the Boettcher Foundation, and National Heart, Lung, and Blood Institute grants R01HL14644 and R01HL148151.

Vesiculation of Red Blood Cells in the Blood Bank: A Multi-Omics Approach towards Identification of Causes and Consequences

Microvesicle generation is an integral part of the aging process of red blood cells in vivo and in vitro. Extensive vesiculation impairs function and survival of red blood cells after transfusion, and microvesicles contribute to transfusion reactions. The triggers and mechanisms of microvesicle generation are largely unknown. In this study, we combined morphological, immunochemical, proteomic, lipidomic, and metabolomic analyses to obtain an integrated understanding of the mechanisms underlying microvesicle generation during the storage of red blood cell concentrates. Our data indicate that changes in membrane organization, triggered by altered protein conformation, constitute the main mechanism of vesiculation, and precede changes in lipid organization. The resulting selective accumulation of membrane components in microvesicles is accompanied by the recruitment of plasma proteins involved in inflammation and coagulation. Our data may serve as a basis for further dissection of the fundamental mechanisms of red blood cell aging and vesiculation, for identifying the cause-effect relationship between blood bank storage and transfusion complications, and for assessing the role of microvesicles in pathologies affecting red blood cells.

Effects of aged stored autologous red blood cells on human plasma metabolome

Cold storage of blood for 5 to 6 weeks has been shown to impair endothelial function after transfusion and has been associated with measures of end-organ dysfunction. Although the products of hemolysis, such as cell-free plasma hemoglobin, arginase, heme, and iron, in part mediate these effects, a complete analysis of transfused metabolites that may affect organ function has not been evaluated to date. Blood stored for either 5 or 42 days was collected from 18 healthy autologous volunteers, prior to and after autologous transfusion into the forearm circulation, followed by metabolomics analyses. Significant metabolic changes were observed in the plasma levels of hemolytic markers, oxidized purines, plasticizers, and oxidized lipids in recipients of blood stored for 42 days, compared with 5 days. Notably, transfusion of day 42 red blood cells (RBCs) increased circulating levels of plasticizers (diethylhexyl phthalate and derivatives) by up to 18-fold. Similarly, transfusion of day 42 blood significantly increased circulating levels of proinflammatory oxylipins, including prostaglandins, hydroxyeicosatrienoic acids (HETEs), and dihydroxyoctadecenoic acids. Oxylipins were the most significantly increasing metabolites (for 9-HETE: up to ∼41-fold, P = 3.7e-06) in day 42 supernatants. Measurements of arginine metabolism confirmed an increase in arginase activity at the expense of nitric oxide synthesis capacity in the bloodstream of recipients of day 42 blood, which correlated with measurements of hemodynamics. Metabolic changes in stored RBC supernatants impact the plasma metabolome of healthy transfusion recipients, with observed increases in plasticizers, as well as vasoactive, pro-oxidative, proinflammatory, and immunomodulatory metabolites after 42 days of storage.

Rejuvenation solution as an adjunct cold storage solution maintains physiological haemoglobin oxygen affinity during early-storage period of red blood cells

BACKGROUND

Red blood cell (RBC) units accumulate morphologic and metabolic lesions during storage before transfusion. Pyruvate-inosine-phosphate-adenine (PIPA) solutions (Rejuvesol, Biomet, Warsaw, IN) can be incubated with RBC units to mitigate storage lesions. This study proposes a PIPA treatment process, termed cold 'rejuvenation', using Rejuvesol as an adjunct additive solution, to prevent biomechanical storage lesions while avoiding the 1 h PIPA incubation required with standard PIPA treatment. We compared the efficacy of cold to standard 'rejuvenation' in improving metabolic lesions that occur during cold storage of RBCs, without altering function.

METHODS

Twelve leucoreduced, A-positive RBC units were obtained. Each unit was aliquoted into either control (standard storage), washed (W), standard rejuvenation (SR) or cold rejuvenation (CR) groups, the latter two requiring washing. A volume-adjusted dose of Rejuvesol was instilled into the CR group upon receipt (Day 3). After 15 days of storage, p50, RBC deformability, in-bag haemolysis and mechanical fragility were analysed. 'Any treatment' is defined as W, SR and CR, with comparisons in reference to control.

RESULTS

Higher p50s were seen in rejuvenated groups (>30 mmHg vs. <19 mmHg; P < 0·0001). Any treatment significantly increased elongation index (P = 0·034) but did not significantly increase in-bag haemolysis (P = 0·062). Mechanical fragility was not significantly different between groups (P = 0·055) at baseline, but the control (CTL) group was more fragile after 2 h in a cardiac bypass simulation than any treatment (P < 0·0001).

CONCLUSIONS

This study demonstrates that rejuvenation (standard or cold) prevents the leftward p50 shift of storage lesions without detrimental effect on RBC deformity, in-bag haemolysis or mechanical fragility.

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.

Decoding the metabolic landscape of pathophysiological stress-induced cell death in anucleate red blood cells

BACKGROUND

In response to stress, anucleate red blood cells (RBCs) can undergo a process of atypical cell death characterised by intracellular Ca²⁺ accumulation and phosphatidylserine (PS) externalisation. Here we studied alterations in RBC metabolism, a critical contributor to their capacity to survive environmental challenges, during this process.

MATERIALS AND METHODS

Metabolomics analyses of RBCs and supernatants, using ultra-high-pressure liquid chromatography coupled to mass spectrometry, were performed after in vitro exposure of RBCs to different pathophysiological cell stressors, including starvation, extracellular hypertonicity, hyperthermia, and supraphysiological ionic stress. Cell death was examined by flow cytometry.

RESULTS

Our data show that artificially enhancing RBC cytosolic Ca²⁺ influx significantly enhanced purine oxidation and strongly affected cellular bioenergetics by reducing glycolysis. Depleting extracellular Ca²⁺ curtailed starvation-induced cell death, an effect paralleled by the activation of compensatory pathways such as the pentose phosphate pathway, carboxylic acid metabolism, increased pyruvate to lactate ratios (methemoglobin reductase activation), one-carbon metabolism (protein-damage repair) and glutathione synthesis; RBCs exposed to hypertonic shock displayed a similar metabolic profile. Furthermore, cell stress promoted lipid remodelling as reflected by the levels of free fatty acids, acyl-carnitines and CoA precursors. Notably, RBC PS exposure, independently of the stressor, showed significant correlation with the levels of free fatty acids, glutamate, cystine, spermidine, tryptophan, 5-oxoproline, lactate, and hypoxanthine.

DISCUSSION

In conclusion, different cell death-inducing pathophysiological stressors, encountered in various clinical conditions, result in differential RBC metabolic phenotypes, only partly explained by intracellular Ca²⁺ levels and ATP availability.

Metabolic impact of red blood cell exchange with rejuvenated red blood cells in sickle cell patients

BACKGROUND

Red blood cell exchange (RCE) transfusions are a mainstay in the treatment of sickle cell anemia (SCA), and allow a temporary restoration of physiological parameters with respect to erythrocyte oxygen carrying capacity and systems metabolism. Recently, we noted that 1) RCE significantly impacts recipients' metabolism in SCA; 2) fresh and end-of-storage red blood cell (RBC) units differently impact systems of metabolism in healthy autologous recipients; and 3) phosphate/inosine/pyruvate/adenine (PIPA) solution reverses the metabolic age of stored RBCs. Therefore, we hypothesized that RCE with PIPA-treated RBC units could further increase the metabolic benefits of RCE in SCA patients.

STUDY DESIGN AND METHODS

Circulating plasma and erythrocytes were collected from patients with SCA before and after RCE, with either conventional or PIPA-treated RBC units, prior to metabolomics analyses.

RESULTS

Consistent with prior work, RCE significantly decreased circulating levels of markers of systemic hypoxemia (lactate, succinate) and decreased plasma levels of acyl-carnitines and amino acids. However, PIPA-treated exchanges were superior to untreated RCEs, with a higher energy state and an increased capacity to activate the pentose phosphate pathway and glutamine metabolism. In addition, RBCs and plasma from recipients of PIPA-treated RBC units resulted in significantly decreased levels of post-transfusion plasticizers, though at the expense of higher circulating levels of oxidized purines (hypoxanthine, xanthine, and the antioxidant urate).

CONCLUSION

Transfusion of PIPA-treated RBCs further increases the metabolic benefits of RCE to patients with SCA, significantly reducing the levels of post-transfusion plasticizers.

From omics technologies to personalized transfusion medicine

INTRODUCTION

Blood transfusion is the single most frequent in-hospital medical procedure, a life-saving intervention for millions of recipients worldwide every year. Storage in the blood bank is an enabling strategy for this critical procedure, as it logistically solves the issue of making ~110 million units available for transfusion every year. Unfortunately, storage in the blood bank promotes a series of biochemical and morphological changes to the red blood cell that compromise the integrity and functionality of the erythrocyte in vitro and in animal models, and could negatively impact transfusion outcomes in the recipient. Areas covered: While commenting on the clinical relevance of the storage lesion is beyond the scope of this manuscript, here we will review recent advancements in our understanding of the storage lesion as gleaned through omics technologies. We will focus on how the omics-scale appreciation of the biological variability at the donor and recipient level is impacting our understanding of red blood cell storage biology. Expert commentary: Omics technologies are paving the way for personalized transfusion medicine, a discipline that promises to revolutionize a critical field in medical practice. The era of recipient-tailored additives, processing, and storage strategies may not be too far distant in the future.

Extracellular Vesicles in Red Blood Cell Concentrates: An Overview

Red blood cell (RBC) concentrates may be stored for up to 42 days before transfusion to a patient. During storage extracellular vesicles (EVs) develop and can be detected in significant amounts in RBC concentrates. The concentration of EVs is affected by component preparation methods, storage solutions, and inter-donor variation. Laboratory investigations have focused on the effect of EVs on in vitro assays of thrombin generation and immune responses. Assays for EVs in RBC concentrates are not standardized. The aims of this review are to describe the factors that determine the presence of erythrocyte-EVs in RBC concentrates, the current techniques used to characterize them, and the potential role of EV analysis as a quality control maker for RBC storage.

Altered Expression Levels of CD59, but Not CD55, on Red Blood Cells in Stored Blood

OBJECTIVE

Red blood cells (RBCs) in storage undergo structural and biochemical changes that may cause functional effects. Studies exploring structural changes affecting the expression levels of CD55 and CD59 on RBCs are limited. The aim of this study was to investigate the pattern of CD55 and CD59 expression on RBCs in stored blood from Arab donors.

MATERIALS AND METHODS

Flow-cytometric analysis was performed on RBCs from 92 packed RBC (PRBC) units, stored for varying times, and from 56 nonstored RBC from healthy controls using the commercial REDQUANT kit.

RESULTS

The proportions of CD55- and CD59-deficient RBCs from stored PRBC units did not significantly differ when compared with those from healthy controls; however, the mean fluorescent intensity (MFI) of CD59 expression, but not MFI of CD55 expression, on RBCs from stored PRBC units was significantly reduced when compared to the expression of RBCs from healthy controls (p = 0.02). MFI of CD55 expression on RBCs from PRBC units did not significantly differ among the 3 groups of stored RBC; however, there was a statistically significant time-dependent preferential decline in MFI of CD59 expression on RBCs from stored PRBC units (p < 0.01).

CONCLUSION

There is a preferential time-dependent decline in the expression of CD59, but not of CD55, on stored RBCs, the in vivo significance of which in relation to the response to PRBC transfusion needs further investigation.

Cryopreservation of Red Blood Cells

Glycerol and trehalose are widely used protective agents in the cryopreservation of red blood cells (RBCs). This chapter presents a protocol for use of these agents as cryoprotectants of RBCs, with post-thaw assessment of cell survival and cellular oxidative-reductive status. The main aim is to provide a framework for further studies aimed at improving RBC survival and function and to supply improved biomaterials for studies on RBC biochemistry, major operations, as well as those for urgent use in emergency room situations.

Heterogeneity of blood processing and storage additives in different centers impacts stored red blood cell metabolism as much as storage time: lessons from REDS-III-Omics

BACKGROUND

Biological and technical variability has been increasingly appreciated as a key factor impacting red blood cell (RBC) storability and, potentially, transfusion outcomes. Here, we performed metabolomics analyses to investigate the impact of factors other than storage duration on the metabolic phenotypes of stored RBC in a multicenter study.

STUDY DESIGN AND METHODS

Within the framework of the REDS-III (Recipient Epidemiology and Donor Evaluation Study-III) RBC-Omics study, 13,403 donors were enrolled from four blood centers across the United States and tested for the propensity of their RBCs to hemolyze after 42 days of storage. Extreme hemolyzers were recalled and donated a second unit of blood. Units were stored for 10, 23, and 42 days prior to sample acquisition for metabolomics analyses.

RESULTS

Unsupervised analyses of metabolomics data from 599 selected samples revealed a strong impact (14.2% of variance) of storage duration on metabolic phenotypes of RBCs. The blood center collecting and processing the units explained an additional 12.2% of the total variance, a difference primarily attributable to the storage additive (additive solution 1 vs. additive solution 3) used in the different hubs. Samples stored in mannitol-free/citrate-loaded AS-3 were characterized by elevated levels of high-energy compounds, improved glycolysis, and glutathione homeostasis. Increased methionine metabolism and activation of the transsulfuration pathway was noted in samples processed in the center using additive solution 1.

CONCLUSION

Blood processing impacts the metabolic heterogeneity of stored RBCs from the largest multicenter metabolomics study in transfusion medicine to date. Studies are needed to understand if these metabolic differences influenced by processing/storage strategies impact the effectiveness of transfusions clinically.

Effects of red blood cell (RBC) transfusion on sickle cell disease recipient plasma and RBC metabolism

BACKGROUND

Exchange transfusion is a mainstay in the treatment of sickle cell anemia. Transfusion recipients with sickle cell disease (SCD) can be transfused over 10 units per therapy, an intervention that replaces circulating sickle red blood cells (RBCs) with donor RBCs. Storage of RBCs makes the intervention logistically feasible. The average storage duration for units transfused at the Duke University Medical Center is approximately 2 weeks, a time window that should anticipate the accumulation of irreversible storage lesion to the RBCs. However, no metabolomics study has been performed to date to investigate the impact of exchange transfusion on recipients' plasma and RBC phenotypes.

STUDY DESIGN AND METHODS

Plasma and RBCs were collected from patients with sickle cell anemia before transfusion and within 5 hours after exchange transfusion with up to 11 units, prior to metabolomics analyses.

RESULTS

Exchange transfusion significantly decreased plasma levels of markers of systemic hypoxemia like lactate, succinate, sphingosine 1-phosphate, and 2-hydroxyglutarate. These metabolites accumulated in transfused RBCs, suggesting that RBCs may act as scavenger/reservoirs. Transfused RBCs displayed higher glycolysis, total adenylate pools, and 2,3-diphosphoglycerate, consistent with increased capacity to deliver oxygen. Plasma levels of acyl-carnitines and amino acids decreased, while fatty acids and potentially harmful phthalates increased upon exchange transfusion.

CONCLUSION

Metabolic phenotypes confirm the benefits of the transfusion therapy in transfusion recipients with SCD and the reversibility of some of the metabolic storage lesion upon transfusion in vivo in 2-week-old RBCs. However, results also suggest that potentially harmful plasticizers are transfused.

Metabolomics evaluation of early-storage red blood cell rejuvenation at 4°C and 37°C

BACKGROUND

Refrigerated red blood cell (RBC) storage results in the progressive accumulation of biochemical and morphological alterations collectively referred to as the storage lesion. Storage-induced metabolic alterations can be in part reversed by rejuvenation practices. However, rejuvenation requires an incubation step of RBCs for 1 hour at 37°C, limiting the practicality of providing "on-demand," rejuvenated RBCs. We tested the hypothesis that the addition of rejuvenation solution early in storage as an adjunct additive solution would prevent-in a time window consistent with the average age of units transfused to sickle cell recipients at Duke (15 days)-many of the adverse biochemical changes that can be reversed via standard rejuvenation, while obviating the incubation step.

STUDY DESIGN AND METHODS

Metabolomics analyses were performed on cells and supernatants from AS-1 RBC units (n = 4), stored for 15 days. Units were split into pediatric bag aliquots and stored at 4°C. These were untreated controls, washed with or without rejuvenation, performed under either standard (37°C) or cold (4°C) conditions.

RESULTS

All three treatments removed most metabolic storage by-products from RBC supernatants. However, only standard and cold rejuvenation provided significant metabolic benefits as judged by the reactivation of glycolysis and regeneration of adenosine triphosphate and 2,3-diphosphoglycerate. Improvements in energy metabolism also translated into increased capacity to restore the total glutathione pool and regenerate oxidized vitamin C in its reduced (ascorbate) form.

CONCLUSION

Cold and standard rejuvenation of 15-day-old RBCs primes energy and redox metabolism of stored RBCs, while providing a logistic advantage for routine blood bank processing workflows.

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.

Effect of Liposome Treatment on Hemorheology and Metabolic Profile of Human Red Blood Cells During Hypothermic Storage

BACKGROUND

Ex vivo cold storage of red blood cells (RBCs) for transfusion has long been associated with hypothermic storage lesions. It has been proposed that liposomes can be used to mitigate hemorheological elements of RBC membrane storage lesions. This study aimed to determine the appropriate liposome treatment time and assess the effects of liposome treatment on RBC's hemorheological and metabolic profiles.

MATERIALS AND METHODS

Unilamellar liposomes were synthesized to contain a bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):cholesterol (7:3 mol%). Packed human RBCs (n = 4) were divided into untreated control (HEPES-NaCl solution) and liposome-treated samples (2 mM DOPC liposomes) and treated at days 2, 21, and 42 of hypothermic storage. RBC quality assessment included percent hemolysis, deformability, aggregation, hematological indices, microvesiculation, supernatant potassium, adenosine triphosphate (ATP), and 2,3-diphosphoglycerate (2,3-DPG).

RESULTS

Among the parameters affected by liposome treatment time were deformability, aggregation amplitude (Amp), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and microparticle mean fluorescence intensity. After 6 weeks of storage, aggregation index (AI) and Amp were significantly increased in liposome-treated RBCs (AI: 45.38 ± 1.92% vs. 41.54 ± 4.10%, p = 0.020; Amp: 16.38 ± 2.17 arbitrary units [au] vs. 12.22 ± 3.29 au, p = 0.019). Despite comparable hemolysis levels at 3 and 6 weeks, DOPC-treated RBCs showed significantly increased potassium levels for the same time points (3 weeks: 31.2 ± 2.7 mmol/L vs. 30.8 ± 2.7 mmol/L, p = 0.007; 6 weeks: 45.0 ± 3.0 mmol/L vs. 43.8 ± 3.4 mmol/L, p = 0.013). ATP and 2,3-DPG levels were comparable throughout storage.

CONCLUSIONS

Liposome treatment seemed to be more beneficial when performed at the beginning of storage up to day 21. DOPC liposome treatment resulted in an improvement in human RBC hemorheology upon storage, with no significant impact on metabolic profile.

Time-Course Investigation of Small Molecule Metabolites in MAP-Stored Red Blood Cells Using UPLC-QTOF-MS

Red blood cells (RBCs) are routinely stored for 35 to 42 days in most countries. During storage, RBCs undergo biochemical and biophysical changes known as RBC storage lesion, which is influenced by alternative storage additive solutions (ASs). Metabolomic studies have been completed on RBCs stored in a number of ASs, including SAGM, AS-1, AS-3, AS-5, AS-7, PAGGGM, and MAP. However, the reported metabolome analysis of laboratory-made MAP-stored RBCs was mainly focused on the time-dependent alterations in glycolytic intermediates during storage. In this study, we investigated the time-course of alterations in various small molecule metabolites in RBCs stored in commercially used MAP for 49 days using ultra-high performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-QTOF-MS). These alterations indicated that RBC storage lesion is related to multiple pathways including glycolysis, pentose phosphate pathway, glutathione homeostasis, and purine metabolism. Thus, our findings might be useful for understanding the complexity of metabolic mechanisms of RBCs in vitro aging and encourage the deployment of systems biology methods to blood products in transfusion medicine.